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Sample records for teeth position eruption

  1. Uncovering labially impacted teeth: apically positioned flap and closed-eruption techniques.

    PubMed

    Vermette, M E; Kokich, V G; Kennedy, D B

    1995-01-01

    The purpose of this study was to examine the esthetic and periodontal differences between two methods of uncovering labially impacted maxillary anterior teeth: the apically positioned flap and closed-eruption techniques. The sample consisted of 30 patients who were recalled a minimum of three months after orthodontic treatment of a unilateral labially impacted maxillary anterior tooth. Eighteen of the patients had undergone an apically positioned flap (APF) procedure, and the remaining twelve had undergone the closed-eruption (CE) technique. In the CE group, clinical examination showed less width of attached gingiva on the distal surface and increased probing bone level on the facial surface of the uncovered teeth relative to their contralateral controls. Uncovered teeth in the APF group showed more apical gingival margins on the mesial and facial surfaces; greater crown length on the midfacial surface; increased probing attachment level on the facial surface; increased width of attached gingiva on the facial surface; increased probing bone level on mesial, facial, and distal surfaces; and gingival scarring. Radiographic examination showed shorter roots on the uncovered teeth in both groups. Photographic examination revealed vertical relapse of the uncovered teeth in the APF group. We conclude that labially impacted maxillary anterior teeth uncovered with an apically positioned flap technique have more unesthetic sequalae than those uncovered with a closed-eruption technique.

  2. [Correlations between the presence of a mesiodens and position abnormalities, diastemas, and eruption disturbances of maxillary frontal teeth].

    PubMed

    Baart, J A; Groenewegen, B T; Verloop, M A

    2009-08-01

    A mesiodens is often diagnosed coincidentally during a radiological examination. However, a mesiodens may also be diagnosed in relation to a clinically identified central diastema and an eruption disturbance, or a rotation of a central incisor. In this study of a group of 162 children and adolescents varying in age from 4 to 18 years, with a mesiodens, the frequency of position abnormalities, diastemas, and eruption disturbances of the maxillary frontal teeth was registered retrospectively. One or more of these complications was diagnosed in 72% of the patients. Usually, removal of the mesiodens in children and adolescents results in spontaneous recovery of the complications. Early diagnosis and early treatment are therefore important.

  3. Eruption Time of Permanent Teeth in Pakistani Children

    PubMed Central

    Khan, N

    2011-01-01

    Background: To determine the mean eruption time of permanent teeth of Pakistani children and to evaluate the effects of gender, type of schools, height, weight and body mass index on it. Methods: This cross sectional study was conducted from September 2007 to April 2008. 4370 children of ‘just erupted’ teeth were obtained from 102 randomly selected schools from 18 towns of Karachi, using systematic random sampling procedure. The dental examination was carried out for the selected child. Height, weight and date of birth were also obtained. Two sample‘t’ test and paired ‘t’ test were employed to compare the mean time of eruption between gender and type of schools (private/ public), and upper and lower jaws. Pearson and partial correlations were used to determine the significant relationship between eruption time with height, weight and BMI. Results: The right first molars of upper and lower jaws showed the minimum eruption time. Second molars were the last tooth to emerge. Only 3 teeth showed significant difference of eruption time between the genders. None of contralateral teeth showed any statistical significant difference. All the mandible teeth, except the premolars, erupted earlier than maxillary teeth. Private schools children showed early eruption than the public schools children. The Pearson and partial correlation were significant positively correlated with height. Eruption time of all the teeth, except one, showed positive correlation with weight. Conclusion: The eruption time of Pakistani children are different in many aspects with to other nationalities. PMID:23113104

  4. [A cross-sectional survey on the patterns of primary teeth eruption in 2 581 children].

    PubMed

    Li, R X; Hu, Y

    2017-01-02

    Objective: To investigate the patterns of primary teeth eruption by a cross-sectional survey in 0-40 months old children in Chongqing and to provide normal timetables of tooth eruption that are practical in general physical growth assessment. Method: Data of 2 581 0-40 months old healthy children were collected from January 2014 to January 2016 at Children's Hospital of Chongqing Medical University. General information was recorded by primary child health care doctors, including age, gender, gestation age, birth weight, time and sequence of first primary tooth eruption, number of teeth and age of totally primary teeth emergence. Median and constituent ratio were used in describing the age of tooth eruption and eruption characteristics at different age. Moreover, independent-sample t test, variance analysis, Pearson product-moment correlation and Logistic regression were also involved in data analysis. Result: Totally 2 581 children were involved in this survey, including 506 infants of 0-6 months old, 600 infants of 7-12 months old, 730 toddlers of 13-24 months old and 745 children of 25-40 months old. There were 1 473 boys and 1 108 girls, 89 preterm babies and 2 492 full term babies, 1 829 children with tooth erupted and 626 children with all primary teeth erupted.The age of the first primary tooth eruption was between 2-15 months old ( median age: 8 months old, 95% CI: 2.7-12.7)and for the last primary tooth emergence was between 23-35 months of age (median age: 31 months, 95% CI : 24.7-36.7). The time of first tooth eruption was positively correlated with that of total teeth emergence ( r =0.879, P <0.05). Dental charts (number of tooth for age) of different gender were drawn according to teeth eruption information. The first primary tooth eruption was the incisor of mandible in 95.3% (1 743/1 829)infants and was the incisor of maxilla in 4.6% (84/1 829)infants. During the period of tooth emerging actively (number of teeth ≤16), the number of primary teeth

  5. Factors associated with number of erupted primary teeth in Brazilian children: a cross-sectional study.

    PubMed

    Corrêa-Faria, Patrícia; Leite-Faria, Letícia; Viana, Aline Neves; Marques, Leandro Silva; Ferreira, Fernanda Oliveira; Ramos-Jorge, Maria Letícia

    2013-01-01

    The purpose of this study was to determine whether nutritional status, gender, weight, and height affected the number of erupted primary teeth in six- to 30 month-old children. A cross-sectional study was carried out involving an oral clinical examination, and weight and height measurements of 232 children, as well as a questionnaire filled out by their parents. Statistical analysis involved descriptive data, Spearman's correlation coefficient, Kruskall-Wallis test, and multiple linear regression in two sets, using the enter method to control the confounding factor (age) and the stepwise method for gender, weight, and height ( P<.05). The calculation of effect size proposed by Cohen was used to test the clinical significance of the findings. The number of erupted teeth was not significantly influenced by nutritional status ( P<.58; Kruskal-Wallis test) or gender ( P=.95; Mann-Whitney test). Body weight had a statistically significant association with the number of erupted primary teeth ( P<.001), and height showed a positive correlation with this variable, both independently of the child's age. The number of erupted primary teeth was affected by weight in children of the same age.

  6. Weight, height and eruption times of permanent teeth of children aged 4–15 years in Kampala, Uganda

    PubMed Central

    2013-01-01

    Background Tooth eruption is a continuous biological process by which developing teeth emerge through the jaws and the overlying mucosa to enter into the oral cavity. Tooth eruption time and sequence are important factors in dental treatment planning, particularly in orthodontics, but also in forensic dentistry to estimate age of a child. Tooth eruption time is influenced by many factors. In this study we set out to determine the timing of eruption of permanent teeth and assess its association with the height and weight of school children aged 4–15 years in Kampala, Uganda. Methods This was a cross sectional study comprising of 1041 healthy Ugandan children: boys/girls (520/521) who were consecutively selected from two primary schools in Kampala. The children were clinically assessed for tooth emergency through the oral mucosa as well as measuring their weight and height. The mean and standard deviation of tooth eruption time was estimated for boys and girls. Bivariate analysis was used to assess any significant association between tooth eruption time and demographic variables. Pearson and partial correlation analyses were used to assess any significant association between the tooth eruption time and anthropometric measurements of the children. Results Generally, the mean eruption times for girls were lower compared to boys except for three teeth (#25, #32 and #42) which erupted earlier in boys. The average difference in mean eruption times of all teeth between boys and girls was found to be 0.8 (range, 0–1.5) years. In partial correlation analysis, mean tooth eruption times were positively, but not significantly associated with height while controlling for weight except for the mandibular left central incisor (#31). On the other hand, in partial correlation analysis, mean tooth eruption times were positively associated with weight while controlling for height except for tooth #11, #16, #26 and #41. The weight of the child was significantly correlated with

  7. Teething

    MedlinePlus

    Eruption of primary teeth; Well child care - teething ... 6 and 8 months old. All 20 baby teeth should be in place by the time a ... months old. Some children do not show any teeth until much later than 8 months, but this ...

  8. Implantation of octacalcium phosphate collagen composites (OCP/Col) after extraction of canine deciduous teeth achieved undisturbed permanent tooth eruption.

    PubMed

    Kanda, Naofumi; Matsui, Keiko; Kawai, Tadashi; Edamatsu, Hiroshi; Tanuma, Yuji; Suzuki, Osamu; Takahashi, Tetsu; Kamakura, Shinji

    2016-12-01

    Composite of synthetic octacalcium phosphate and collagen (OCP/Col) enhances bone regeneration if implanted into human, canine, or rodent bone defects. This study was designed to investigate the influence on eruption of the permanent successor tooth and alveolar height of OCP/Col implantation into extraction cavities of deciduous teeth. Disks of OCP/Col prepared from synthetic granules of octacalcium phosphate (OCP) and porcine atelocollagen, and commercially available sintered porous β-tricalcium phosphate (β-TCP) was implanted into the prepared defect of eleven male beagle dogs by extraction of two deciduous premolars. Untreated group had nothing implanted into the prepared defect, and physiological group (Physiol group) was observed without any treatment. Periodical macroscopic and radiographic examinations were performed until the period equivalent to the physiological eruption of permanent successor teeth (P3 and P4). Although no unerupted permanent successor teeth were observed among the OCP/Col, Untreated, and Physiol groups, two permanent successor teeth were unerupted in the β-TCP group. No significant difference of the alveolar heights or the eruptive position in P3 and P4 was observed between OCP/Col and Physiol groups. OCP/Col implantation in the alveolar region that included the unerupted permanent successor teeth would cause no disturbance of permanent tooth eruption and preserve the alveolar ridge. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Effects of different combinations of fused primary teeth on eruption of the permanent successors.

    PubMed

    Tsujino, Keiichiro; Yonezu, Takuro; Shintani, Seikou

    2013-01-01

    The fusion of primary teeth may be associated with the absence of 1 of the 2 permanent successors. Moreover, even if both successors erupt, developmental disturbances such as microdontia or delayed tooth formation may occur. The purpose of this study was to elucidate the effects of different combinations of fused primary teeth on the eruption of permanent successors. One hundred ninety-seven children with 247 fused primary teeth were examined. Combinations of primary teeth involved in the fusion were identified, and the effects of these different combinations on the presence, morphology, and eruption of the permanent successors were determined. Three types of fusion in the primary teeth were identified: (1) between the maxillary central and lateral incisors (UCI/LI); (2) between the mandibular central and lateral incisors (LCI/LI); and (3) between the mandibular lateral incisor and canine (LLI/C). The results revealed an absence of the successional lateral incisor in 65% of UCI/LI cases and 74% of LLI/C cases, whereas only 16% of LCI/LI cases resulted in a missing successor. Fused primary teeth are highly correlated with the absence of permanent teeth, and the prevalence depends on the combination of fused primary teeth.

  10. Timing of fluoride intake and dental fluorosis on late-erupting permanent teeth

    PubMed Central

    Bhagavatula, Pradeep; Levy, Steven M; Broffitt, Barbara; Weber-Gasparoni, Karin; Warren, John J

    2015-01-01

    Objective Very few studies have examined the relationship between timing of fluoride intake and development of dental fluorosis on late-erupting permanent teeth using period-specific fluoride intake information. This study examined this relationship using longitudinal fluoride intake information from the Iowa Fluoride Study. Methods Participants’ fluoride exposure and intake (birth to 10 years) from water, beverages, selected food products, dietary fluoride supplements and fluoride toothpaste was collected using questionnaires sent to parents at 3- and 4- month intervals from birth to age 48 months, and every six months thereafter. Three trained and calibrated examiners used the Fluorosis Risk Index (FRI) categories to assess 16 late-erupting teeth among 465 study participants. A tooth was defined as having definitive fluorosis if any of the zones on that tooth had an FRI score of 2 or 3. Participants with questionable fluorosis were excluded from analyses. Descriptive and logistic regression analyses were performed to assess the importance of fluoride intake during different time periods. Results Most dental fluorosis in the study population was mild, with only 4 subjects (1%) having severe fluorosis (FRI Score 3). The overall prevalence of dental fluorosis was 27.8%. Logistic regression analyses showed that fluoride intake from each of the individual years from age 2 to 8 years plays an important role in determining the risk of dental fluorosis for most late-erupting permanent teeth. The strongest association for fluorosis on the late-erupting permanent teeth was with fluoride intake during the sixth year of life. Conclusion Late-erupting teeth may be susceptible to fluorosis for an extended period from about age 2 to 8 years. Although not as visually prominent as the maxillary central incisors, some of the late-erupting teeth are esthetically important and this should be taken into consideration when making recommendations about dosing of fluoride intake. PMID

  11. Timing of fluoride intake and dental fluorosis on late-erupting permanent teeth.

    PubMed

    Bhagavatula, Pradeep; Levy, Steven M; Broffitt, Barbara; Weber-Gasparoni, Karin; Warren, John J

    2016-02-01

    Very few studies have examined the relationship between timing of fluoride intake and development of dental fluorosis on late-erupting permanent teeth using period-specific fluoride intake information. This study examined this relationship using longitudinal fluoride intake information from the Iowa Fluoride Study. Participants' fluoride exposure and intake (birth to 10 years of age) from water, beverages, selected food products, dietary fluoride supplements, and fluoride toothpaste was collected using questionnaires sent to parents at 3- and 4- month intervals from birth to 48 months of age and every 6 months thereafter. Three trained and calibrated examiners used the Fluorosis Risk Index (FRI) categories to assess 16 late-erupting teeth among 465 study participants. A tooth was defined as having definitive fluorosis if any of the zones on that tooth had an FRI score of 2 or 3. Participants with questionable fluorosis were excluded from analyses. Descriptive and logistic regression analyses were performed to assess the importance of fluoride intake during different time periods. Most dental fluorosis in the study population was mild, with only four subjects (1%) having severe fluorosis (FRI Score 3). The overall prevalence of dental fluorosis was 27.8%. Logistic regression analyses showed that fluoride intake from each of the individual years from age 2 to 8 plays an important role in determining the risk of dental fluorosis for most late-erupting permanent teeth. The strongest association for fluorosis on the late-erupting permanent teeth was with fluoride intake during the sixth year of life. Late-erupting teeth may be susceptible to fluorosis for an extended period from about age 2 to 8. Although not as visually prominent as the maxillary central incisors, some of the late-erupting teeth are esthetically important and this should be taken into consideration when making recommendations about dosing of fluoride intake. © 2015 John Wiley & Sons A/S. Published by

  12. Eruption chronology of the first deciduous teeth in children born prematurely with birth weight less than 1500g

    PubMed Central

    F., Pedro Garcia; Falcão, Mário Cícero

    2014-01-01

    Objective: To describe the eruption chronology of the first deciduous teeth in premature infants with birth weight less than 1500g and to compare it according to gender and nutritional status at birth. Methods: Longitudinal study including 40 low birth weight premature infants of both genders. The tooth was considered erupted when the crown went through the gum and became part of the oral environment. The comparison of the eruption chronology in relation to gender and among children appropriate or small for gestational age was done by Student's t-test, being significant p<0.05. Results: The eruption of the first tooth (teeth) occurred, on average, with 11.0±2.1 months of chronological age and with 9.6±1.9 months corrected for prematurity. The first erupted teeth were the lower central incisors. The average eruption for males was 9.7±1.9 and, for females, 9.5±1.9 months, both corrected for prematurity (p=0.98). The average eruption in children with birth weight appropriate for gestational age was 10.1±1.4 months; for small for gestational age, it was 9.4±2.2, also corrected for prematurity (p=0.07). Conclusions: The average eruption age of the first teeth, corrected for prematurity, was 9.6 months. Sex and nutritional status at birth did not change the eruption chronology. PMID:24676185

  13. Eruption chronology of the first deciduous teeth in children born prematurely with birth weight less than 1500 g.

    PubMed

    Neto, Pedro Garcia F; Falcão, Mário Cícero

    2014-03-01

    To describe the eruption chronology of the first deciduous teeth in premature infants with birth weight less than 1500 g and to compare it according to gender and nutritional status at birth. Longitudinal study including 40 low birth weight premature infants of both genders. The tooth was considered erupted when the crown went through the gum and became part of the oral environment. The comparison of the eruption chronology in relation to gender and among children appropriate or small for gestational age was done by Student's t-test, being significant p<0.05. The eruption of the first tooth (teeth) occurred, on average, with 11.0±2.1 months of chronological age and with 9.6±1.9 months corrected for prematurity. The first erupted teeth were the lower central incisors. The average eruption for males was 9.7±1.9 and, for females, 9.5±1.9 months, both corrected for prematurity (p=0.98). The average eruption in children with birth weight appropriate for gestational age was 10.1±1.4 months; for small for gestational age, it was 9.4±2.2, also corrected for prematurity (p=0.07). The average eruption age of the first teeth, corrected for prematurity, was 9.6 months. Sex and nutritional status at birth did not change the eruption chronology.

  14. Characteristics of the gubernaculum tracts in mesiodens and maxillary anterior teeth with delayed eruption on MDCT and CBCT.

    PubMed

    Oda, Masafumi; Nishida, Ikuko; Miyamoto, Ikuya; Habu, Manabu; Yoshiga, Daigo; Kodama, Masaaki; Osawa, Kenji; Tanaka, Tatsurou; Kito, Shinji; Matsumoto-Takeda, Shinobu; Wakasugi-Sato, Nao; Nishimura, Shun; Tominaga, Kazuhiro; Yoshioka, Izumi; Maki, Kenshi; Morimoto, Yasuhiro

    2016-10-01

    To elucidate the characteristics of the gubernaculum tracts (GTs) in maxillary anterior teeth with normal or delayed eruption and in mesiodens by using multidetector computed tomography and cone beam computed tomography. The characteristics of GTs in maxillary anterior teeth of 205 patients with impacted mesiodens were retrospectively analyzed by using multidetector computed tomography and cone beam computed tomography. The GTs of teeth with normal or delayed eruption and the GTs of mesiodens were examined. The detection ratio of GTs in impacted mesiodens and anterior teeth with delayed eruption was significantly lower than in teeth with normal eruption. A significant difference in the angulation was found between normal and delayed eruptions. Almost all detectable GTs in the inverted mesiodens were derived from the incisive canal, while the remaining were from the alveolar crest. The connecting area of major GTs to tooth in inverted mesiodens was the cervical or root area, but in all other anterior teeth, it was the crown area. GTs of inverted mesiodens may exhibit characteristics that are different from those of normal GTs when the teeth and/or the palate are developing. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Management of Delayed Eruption of Permanent Maxillary Incisor associated with the Presence of Supernumerary Teeth: A Case Report

    PubMed Central

    Nagpal, Rajni; Singh, Mousumi; Chaudhary, Seema

    2011-01-01

    A supernumerary tooth is one that is additional to the normal series and can be found in almost any region of the dental arch. Clinically, supernumerary teeth are able to cause different local disorders. It is important for the dentist to be aware of the clinical complications of supernumerary teeth, the most common being the delayed eruption of permanent teeth. Early diagnosis and management of supernumerary teeth is important to prevent the need for more complex surgical and orthodontic treatment. This case report highlights the problem of delayed eruption of permanent maxillary left central incisor in a 9-year-old boy due to two supernumerary teeth, one tuberculate type and other impacted inverted mesiodens. PMID:27678238

  16. Implant Site Development by Orthodontic Forced Eruption of Nontreatable Teeth: A Case Report

    PubMed Central

    Rokn, Amir Reza; Saffarpour, Anna; Sadrimanesh, Rouzbeh; Iranparvar, Kaveh; Saffarpour, Aida; Mahmoudzadeh, Majid; Soolari, Ahmad

    2012-01-01

    Background: Loss of bone and soft tissue attachment are common sequelae of periodontitis that may jeopardize the aesthetic outcome and compromise the functional and aesthetic outcomes of treatment. The following case report describes one of the most predictable techniques of vertical ridge augmentation, which is orthodontic extrusion or forced eruption of hopeless teeth. Method: A 34-year-old woman who presented with severe attachment loss and deep pockets was diagnosed with generalized aggressive periodontitis. The mobile maxillary incisors were consequently extracted and were replaced with dental implants. However, prior to extraction, orthodontic extrusion of the hopeless incisors was performed to correct vertical ridge defects. Following extrusion and extraction of the maxillary incisors, to prevent soft tissue collapse and to preserve the papillae during socket healing, the crowns of the extracted teeth were used as pontics on a removable partial provisional denture. After 8 weeks, the implants were placed, and an immediate functional restoration was delivered. After 4 months of healing, a fixed definitive partial prosthesis was fabricated and delivered. Result: After periodontal treatment, over a 2-year period, the progression of aggressive periodontitis was controlled. The mean vertical movement of marginal bone was 3.6 mm. The use of the crowns of extracted teeth appears to be an effective method to maintain papillae. Conclusions: Orthodontic extrusion is a predictable method for the correction of vertical ridge defects. Orthodontic treatment does not aggravate or hasten the progression of aggressive periodontitis. PMID:22715348

  17. AN ERUPTION PATTERN OF DECIDUOUS TEETH IN CHILDREN BORN WITH FETAL MACROSOMIA DURING THE FIRST YEAR OF LIFE.

    PubMed

    Garmash, O

    2017-02-01

    The paper aims at studying the effect of body overweight at birth on the dental health of 482 children in the Kharkiv City (Ukraine) during their first year of life over the 2001 and 2013 interval. The macrosomia set is comprised of the medical records of the children born with fetal macrosomia, and the normosimia set of the medical records of the children born with weight and height that correspond to the gestation age. The gestation age of all children is 37 to 42 weeks'. To determine the average time of first tooth eruption and deciduous teeth growth rate for each of the sets under study, we have used the hypothesis about a linear dependence between the number of erupted teeth and the age of the child. Processing statistical data is performed applying the multiple linear regression analysis. The reasons for macrosomia in the children are examined. The number of pregnancies and deliveries influence the likelihood of having a child with fetal macrosomia. A greater likelihood of having a child with fetal macrosomia in the older parents is not found. The correlation between the states of a child at birth (macrosomia/normosimia) and terms of deciduous tooth eruption (the delayed/timely/early eruption) expressed in a number of teeth at the age of one year is determined. The difference in the teeth growth rate between the boys and girls within the both sets are insignificant. The children born with macrosomia have a lower rate (approximately 0.1 tooth per month) of teeth growth and a greater spread in the number of teeth that erupt by a certain age.

  18. Inactivation of IL11 Signaling Causes Craniosynostosis, Delayed Tooth Eruption, and Supernumerary Teeth

    PubMed Central

    Nieminen, Pekka; Morgan, Neil V.; Fenwick, Aimée L.; Parmanen, Satu; Veistinen, Lotta; Mikkola, Marja L.; van der Spek, Peter J.; Giraud, Andrew; Judd, Louise; Arte, Sirpa; Brueton, Louise A.; Wall, Steven A.; Mathijssen, Irene M.J.; Maher, Eamonn R.; Wilkie, Andrew O.M.; Kreiborg, Sven; Thesleff, Irma

    2011-01-01

    Craniosynostosis and supernumerary teeth most often occur as isolated developmental anomalies, but they are also separately manifested in several malformation syndromes. Here, we describe a human syndrome featuring craniosynostosis, maxillary hypoplasia, delayed tooth eruption, and supernumerary teeth. We performed homozygosity mapping in three unrelated consanguineous Pakistani families and localized the syndrome to a region in chromosome 9. Mutational analysis of candidate genes in the region revealed that all affected children harbored homozygous missense mutations (c.662C>G [p.Pro221Arg], c.734C>G [p.Ser245Cys], or c.886C>T [p.Arg296Trp]) in IL11RA (encoding interleukin 11 receptor, alpha) on chromosome 9p13.3. In addition, a homozygous nonsense mutation, c.475C>T (p.Gln159X), and a homozygous duplication, c.916_924dup (p.Thr306_Ser308dup), were observed in two north European families. In cell-transfection experiments, the p.Arg296Trp mutation rendered the receptor unable to mediate the IL11 signal, indicating that the mutation causes loss of IL11RA function. We also observed disturbed cranial growth and suture activity in the Il11ra null mutant mice, in which reduced size and remodeling of limb bones has been previously described. We conclude that IL11 signaling is essential for the normal development of craniofacial bones and teeth and that its function is to restrict suture fusion and tooth number. The results open up the possibility of modulation of IL11 signaling for the treatment of craniosynostosis. PMID:21741611

  19. Inactivation of IL11 signaling causes craniosynostosis, delayed tooth eruption, and supernumerary teeth.

    PubMed

    Nieminen, Pekka; Morgan, Neil V; Fenwick, Aimée L; Parmanen, Satu; Veistinen, Lotta; Mikkola, Marja L; van der Spek, Peter J; Giraud, Andrew; Judd, Louise; Arte, Sirpa; Brueton, Louise A; Wall, Steven A; Mathijssen, Irene M J; Maher, Eamonn R; Wilkie, Andrew O M; Kreiborg, Sven; Thesleff, Irma

    2011-07-15

    Craniosynostosis and supernumerary teeth most often occur as isolated developmental anomalies, but they are also separately manifested in several malformation syndromes. Here, we describe a human syndrome featuring craniosynostosis, maxillary hypoplasia, delayed tooth eruption, and supernumerary teeth. We performed homozygosity mapping in three unrelated consanguineous Pakistani families and localized the syndrome to a region in chromosome 9. Mutational analysis of candidate genes in the region revealed that all affected children harbored homozygous missense mutations (c.662C>G [p.Pro221Arg], c.734C>G [p.Ser245Cys], or c.886C>T [p.Arg296Trp]) in IL11RA (encoding interleukin 11 receptor, alpha) on chromosome 9p13.3. In addition, a homozygous nonsense mutation, c.475C>T (p.Gln159X), and a homozygous duplication, c.916_924dup (p.Thr306_Ser308dup), were observed in two north European families. In cell-transfection experiments, the p.Arg296Trp mutation rendered the receptor unable to mediate the IL11 signal, indicating that the mutation causes loss of IL11RA function. We also observed disturbed cranial growth and suture activity in the Il11ra null mutant mice, in which reduced size and remodeling of limb bones has been previously described. We conclude that IL11 signaling is essential for the normal development of craniofacial bones and teeth and that its function is to restrict suture fusion and tooth number. The results open up the possibility of modulation of IL11 signaling for the treatment of craniosynostosis. Copyright © 2011 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  20. The Anti-Inflammatory Effects of Matrix Metalloproteinase-3 on Irreversible Pulpitis of Mature Erupted Teeth

    PubMed Central

    Eba, Hisanori; Murasawa, Yusuke; Iohara, Koichiro; Isogai, Zenzo; Nakamura, Hiroshi; Nakamura, Hiroyuki; Nakashima, Misako

    2012-01-01

    Matrix metalloproteinases (MMPs) are involved in extracellular matrix degradation and the modulation of cell behavior. These proteinases have also been implicated in tissue repair and regeneration. Our previous studies have demonstrated that MMP-3 elicits stimulatory effects on the proliferation and the migration of endothelial cells as well as anti-apoptotic effects on these cells in vitro. In addition, we found that MMP-3 enhanced the regeneration of lost pulp tissue in a rat incisor pulp injury model. However, continuously erupting rodent incisors exhibit significantly different pulp organization compared with mature erupted teeth. Therefore, we have further extended these studies using a canine irreversible pulpitis model to investigate the effects of MMP-3. In this study, the crowns of the canine mature premolars were removed and the pulp tissues were amputated. The amputated pulp tissues remained exposed for 24 or 72 hours to induce mild or severe irreversible pulpitis, respectively, followed by sealing of the cavities. In both models, the whole pulp tissues became necrotic by day 14. In this mild pulpitis model, the regeneration of pulp tissue with vasculature and nerves was observed until 14 days after sealing with MMP-3, followed by extracellular matrix formation in the regenerated pulp tissues until day 28. The treatment with MMP-3 resulted in a decrease in the number of macrophage and antigen-presenting cells and a significant inhibition of IL-6 expression on day 3. The inhibition of MMP-3 activity abolished these anti-inflammatory effects. Immunofluorescence staining demonstrated that MMP-3 was involved in the modification of serum-derived hyaluronan-associated proteins and hyaluronan (SHAP-HA) complexes possibly through the degradation of versican. These results demonstrate that MMP-3 can act as an anti-inflammatory agent and suggest that MMP-3 might represent a useful therapy for the treatment of mild irreversible pulpitis. PMID:23285075

  1. The anti-inflammatory effects of matrix metalloproteinase-3 on irreversible pulpitis of mature erupted teeth.

    PubMed

    Eba, Hisanori; Murasawa, Yusuke; Iohara, Koichiro; Isogai, Zenzo; Nakamura, Hiroshi; Nakamura, Hiroyuki; Nakashima, Misako

    2012-01-01

    Matrix metalloproteinases (MMPs) are involved in extracellular matrix degradation and the modulation of cell behavior. These proteinases have also been implicated in tissue repair and regeneration. Our previous studies have demonstrated that MMP-3 elicits stimulatory effects on the proliferation and the migration of endothelial cells as well as anti-apoptotic effects on these cells in vitro. In addition, we found that MMP-3 enhanced the regeneration of lost pulp tissue in a rat incisor pulp injury model. However, continuously erupting rodent incisors exhibit significantly different pulp organization compared with mature erupted teeth. Therefore, we have further extended these studies using a canine irreversible pulpitis model to investigate the effects of MMP-3. In this study, the crowns of the canine mature premolars were removed and the pulp tissues were amputated. The amputated pulp tissues remained exposed for 24 or 72 hours to induce mild or severe irreversible pulpitis, respectively, followed by sealing of the cavities. In both models, the whole pulp tissues became necrotic by day 14. In this mild pulpitis model, the regeneration of pulp tissue with vasculature and nerves was observed until 14 days after sealing with MMP-3, followed by extracellular matrix formation in the regenerated pulp tissues until day 28. The treatment with MMP-3 resulted in a decrease in the number of macrophage and antigen-presenting cells and a significant inhibition of IL-6 expression on day 3. The inhibition of MMP-3 activity abolished these anti-inflammatory effects. Immunofluorescence staining demonstrated that MMP-3 was involved in the modification of serum-derived hyaluronan-associated proteins and hyaluronan (SHAP-HA) complexes possibly through the degradation of versican. These results demonstrate that MMP-3 can act as an anti-inflammatory agent and suggest that MMP-3 might represent a useful therapy for the treatment of mild irreversible pulpitis.

  2. Anatomic (positional) variation of maxillary wisdom teeth with special regard to the maxillary sinus.

    PubMed

    Lanzer, Martin; Pejicic, Rada; Kruse, Astrid L; Schneider, Thomas; Grätz, Klaus W; Lübbers, Heinz-Theo

    2015-01-01

    The removal of wisdom teeth is one of the most common interventions in oral surgery. In order to avoid complications, a profound knowledge of the anatomy of teeth and adjacent tissues is crucial. In the case of maxillary wisdom teeth, their relationship to the maxillary sinus, to the pterygoid fossa, to the maxillary tuber and the adjacent venous plexus is particularly important. Three-dimensional (3D) imaging, for example by means of cone beam computed tomography (CBCT), is increasingly utilized in practice. However, the necessity of CBCT imaging is still a matter of intensive debate. The aim of this study was to describe the anatomic (positional) variation of maxillary wisdom teeth and, based on these findings, to elucidate the additional benefit of such imaging. A retrospective case study was performed using patients examined by means of CBCT imaging in the Department of Dento-Maxillofacial Radiology during the period from 2008 to 2013. Primary study variables comprised the spatial relationship of the teeth to the maxillary sinus, the degree of retention and root development, the covering of the root with bone and mucosa, the root configuration, and the developmental stage of the tooth. In addition, the association of the inclination of teeth in the transversal and sagittal plane with the above variables was evaluated. Descriptive statistical parameters were calculated for all results of the examination. In total, CBCT recordings of 713 maxillary wisdom teeth from 430 patients were evaluated. Their mean age was 29.8 years, and the proportion of male patients slightly prevailed (54.4%). Most teeth exhibited fully developed roots (64.1%). Overall 22.9% of third molars were impacted, 32.3% were retained, and 6.5% were erupting. In more than a third of the patients, wisdom teeth were in occlusion. The inclination of the third molars both in the transversal and sagittal plane was significantly associated with the distance of the root from the maxillary sinus as well

  3. Assisted eruption of impacted teeth into an alveolar bone graft in a patient with cleft lip and palate.

    PubMed

    Peamkaroonrath, Chonthicha; Manosudprasit, Montien; Godfrey, Keith

    2008-11-01

    To assist the eruption of impacted upper teeth into an alveolar bone graft in a patient with a unilateral cleft lip and palate. An 8-year-old Thai boy with left unilateral complete cleft lip and palate had the chief complaint of anterior crossbite. He presented with a mild skeletal 3, dental Class III subdivision malocclusion, anterior crossbite, left unilateral posterior crossbite, moderate crowding in the upper arch with impaction of upper the left lateral incisor (tooth 22) and canine (tooth 23). In the first phase of treatment the posterior crossbite was corrected with a removable appliance with a 3-way screw. In the second phase the impacted teeth were surgically exposed, moved into the alveolar bone graft and the teeth aligned with fixed appliances. The upper left lateral incisor was extracted because of its questionable longevity. The orthodontic treatment resulted in normal overjet, overbite and an acceptable facial profile. A prosthesis replaced tooth 22. Forced eruption of impacted teeth can be carried out successfully in the cleft patients after an appropriate treatment plan has been formulated and following preparation of alveolar bone graft in the cleft site.

  4. The gothic arch tracing and the upper canine teeth as guides in the positioning of upper posterior teeth.

    PubMed

    el-Gheriani, A S; Davies, A L; Winstanley, R B

    1989-09-01

    The relationship between the position of the buccal cusps of the natural upper posterior teeth and the distance between the lateral arms of the Gothic arch tracing or the distance between the upper canine teeth has been found to be constant to within +/- 2 mm. This may be of value when setting up artificial teeth for denture patients, enabling them to be positioned close to the natural predecessors.

  5. The association between orthodontic treatment and third molar position, inferior alveolar nerve involvement, and prediction of wisdom tooth eruption.

    PubMed

    Miclotte, Annelie; Franco, Ademir; Guerrero, Maria Eugenia; Willems, Guy; Jacobs, Reinhilde

    2015-05-01

    The present study aims to compare mandibular third molar position in relation to the mandibular ramus, mandibular third molar angulation, potential impaction and nerve involvement in orthodontic treated versus untreated subjects. The sample consisted of 300 panoramic radiographs 119 males (mean age 16.9 years); 181 females (mean age 16.8 years), contrasting an orthodontically treated (n = 150) to an untreated group (n = 150). Only patients with a full mandibular dentition were included. Pell and Gregory (Dent Digest 39: 330-338, 1933), Winter (Principles of exodontia as applied to the impacted third molars, 1926) and Félez-Gutierrez modified by Gomes (Study of nerve lesion following mandibular third molar surgery, 2011) classifications were used. Radiological information was used to predict eruption. Data was analyzed using frequency analysis and Chi-square testing. 220 lower wisdom teeth (73.3%) were impacted in the treated group, opposed to 236 impacted lower wisdom teeth (78.7%) in the untreated group. A close relation with the mandibular nerve was observed 125 times (41.7%) in the treated group, opposed to an incidence of 112 (37.3%) in the untreated group. The differences were not statistically significant. A partial eruption was predicted for 153 (51%) lower wisdom teeth in the treated group, opposed to 106 (35%) in the untreated group and an impossible eruption in 67 (22%) in the treated group, opposed to 130 (43%). These differences were statistically significant (p < 0.05). The significant outcomes indicate that orthodontically treated patients may develop a higher likeliness to partially erupted third molars, which potentially leads to local clinical morbidities, such as pericoronitis and caries on adjacent teeth. In this context, it may support third molar extractions at an earlier stage in particular cases.

  6. Uptake of fluoride into developing sheep teeth, following the 1995 volcanic eruption of Mt Ruapehu, New Zealand

    NASA Astrophysics Data System (ADS)

    Coote, G. E.; Cutress, T. W.; Suckling, G. W.

    1997-07-01

    In the southern Spring of 1995 (mid-October) the active volcano Mt Ruapehu in the central North Island of New Zealand erupted explosively, spreading up to 40 million m 3 of rhyolite tephra over thousands of km 2 of farmland during the lambing season. This ash contained a high concentration of soluble fluoride, and more than 2000 lactating ewes died of acute fluoride poisoning. To investigate the effects of this brief but acute dose on the teeth of grazing animals we examined the distributions of fluorine and calcium in the permanent incisor teeth of sheep which were one year old at the time. Where part of an incisor had been in the first (secretory) stage of calcification the erupted tooth disclosed surface pitting, a thin layer of enriched mineral across the enamel with as much as 1000 ppm F w/w, and a separate layer with ˜4000 ppm down the dentine. The part of an incisor which had attained the later (maturation) stage showed enriched layers only in the outer enamel and in the dentine. This study has demonstrated some important features of the calcification process, and the risk of fluoride toxicity to grazing animals.

  7. Impact of birth characteristics, breast feeding and vital statistics on the eruption of primary teeth among healthy infants in Saudi Arabia: an observational study

    PubMed Central

    Alnemer, Kholoud Abdullah; Althubaiti, Alaa M; Bawazeer, Manal

    2017-01-01

    Objectives This study aimed to explore the impact of gender, birth weight, maternal age, type of delivery, gestational age and feeding practices on the eruption of teeth in children with no underlying medical conditions or developmental defects in their first year of life. Design A cross-sectional observational study design was used. Setting A primary healthcare setting in Riyadh, Saudi Arabia. Participants All children in their first year of life attending a vaccination clinic (n=422) were included in the study. Infants with chronic childhood illnesses, those who were below the 5th percentile in height or weight, infants with congenital birth defects and chronic illnesses, infants who were born preterm and low birth weight infants were excluded from the study. Outcome measures The type of delivery, birth weight, age of mother, height and weight percentile for age (as plotted on the WHO growth chart for infants) and feeding practices were recorded by the examiner, and this was followed by a clinical examination to determine the presence or absence of each tooth. Regression models were developed to determine the effect of the different variables on the presence of primary teeth. Results There was a significant association between the weight percentile of the child (adjusted for age) and the number of erupted primary teeth, suggesting that heavier children have an earlier eruption of teeth. No association was observed between birth weight, height percentile for age or maternal age at the time of birth and the number of erupted primary teeth. Children who were exclusively breast fed were significantly more likely to have an erupted first primary tooth earlier than non-breastfed group. Conclusions Breast feeding and the weight of the child may have an influence on the eruption of primary teeth in the first year of life. PMID:29248886

  8. Root resorptions related to ectopic and normal eruption of maxillary canine teeth - A 3D study.

    PubMed

    Hadler-Olsen, Sigurd; Pirttiniemi, Pertti; Kerosuo, Heidi; Bolstad Limchaichana, Napat; Pesonen, Paula; Kallio-Pulkkinen, Soili; Lähdesmäki, Raija

    2015-01-01

    To assess the incidence and severity of root resorption of maxillary incisors caused by ectopically and normally erupting maxillary canines and to analyse factors influencing root resorption of incisors using cone beam computed tomography. The study sample comprised 59 patients with a total of 80 canines. Forty-six of the canines, in 37 patients, were defined as ectopic and 34 canines, in 22 patients, were defined as normal. The severity of root resorptions were analysed according to studies by Ericson and Kurol. Multiple logistics regression was used to evaluate the association between various factors and root resorptions. The prevalence of root resorptions was significantly higher in the ectopic canine group, 11.0% of the central incisors and 67.6% of the lateral incisors in comparison to 0% and 36.2% in the normal erupting group. Most resorptions were defined as 'slight' and were located in the middle third of the root. There was a statistically significant relationship between canines located mesial to the midline of the lateral incisor and root resorption on the maxillary incisors. The present results show that root resorption of maxillary lateral incisors was common in patients referred to CBCT imaging due to maxillary canine eruption disturbances. Although significantly more frequent in patients with ectopically erupting canines, lateral incisor resorption was also found in association with approximately every third of the normally erupting canines. The best predictor for root resorption seemed to be location of the canine mesial in relation to the midline of the lateral incisor root.

  9. Zebrafish sp7 mutants show tooth cycling independent of attachment, eruption and poor differentiation of teeth.

    PubMed

    Kague, E; Witten, P E; Soenens, M; Campos, C L; Lubiana, T; Fisher, S; Hammond, C; Brown, K Robson; Passos-Bueno, M R; Huysseune, A

    2018-02-02

    The capacity to fully replace teeth continuously makes zebrafish an attractive model to explore regeneration and tooth development. The requirement of attachment bone for the appearance of replacement teeth has been hypothesized but not yet investigated. The transcription factor sp7 (osterix) is known in mammals to play an important role during odontoblast differentiation and root formation. Here we study tooth replacement in the absence of attachment bone using sp7 zebrafish mutants. We analysed the pattern of tooth replacement at different stages of development and demonstrated that in zebrafish lacking sp7, attachment bone is never present, independent of the stage of tooth development or fish age, yet replacement is not interrupted. Without bone of attachment we observed abnormal orientation of teeth, and abnormal connection of pulp cavities of predecessor and replacement teeth. Mutants lacking sp7 show arrested dentinogenesis, with non-polarization of odontoblasts and only a thin layer of dentin deposited. Osteoclast activity was observed in sp7 mutants; due to the lack of bone of attachment, remodelling was diminished but nevertheless present along the pharyngeal bone. We conclude that tooth replacement is ongoing in the sp7 mutant despite poor differentiation and defective attachment. Without bone of attachment tooth orientation and pulp organization are compromised. Copyright © 2018 Elsevier Inc. All rights reserved.

  10. A Combined Periodontal – Prosthetic Treatment Approach to Manage Unusual Gingival Visibility in Resting Lip Position and Inversely Inclined Upper Anterior Teeth: A Case Report with Discussion

    PubMed Central

    Biniraj, K R; Janardhanan, Mahija; Sunil, M M; Sagir, Mohammed; Hariprasad, A; Paul, Tony P; Emmatty, Rishi

    2015-01-01

    Excessive gingival visibility during smile is a common esthetic complaint in dentistry, but excessive gingival visibility in resting lip position is relatively uncommon condition. Several exclusive radical to conservative surgical treatment or its combination with orthodontic therapy to treat this condition are within the reach of every patient nowadays. A case report of an excessive gingival visibility because of altered passive eruption along with inversely inclined maxillary anterior teeth is presented here. A relatively simple treatment approach combining periodontal and restorative therapy is used here to achieve the desirable aesthetic results. The gingival exposure resulting from altered passive eruption was completely managed by a gingivectomy, but the inclined appearance of teeth was still an aesthetic complaint. After complete healing of gingivectomy surgery, appropriately designed crowns were given to rectify the inversely inclined appearance. A complete rehabilitation of patient’s smile could be achieved, the case was followed up for 3 years and the condition was found satisfactory. PMID:25878482

  11. Application of age estimation methods based on teeth eruption: how easy is Olze method to use?

    PubMed

    De Angelis, D; Gibelli, D; Merelli, V; Botto, M; Ventura, F; Cattaneo, C

    2014-09-01

    The development of new methods for age estimation has become with time an urgent issue because of the increasing immigration, in order to estimate accurately the age of those subjects who lack valid identity documents. Methods of age estimation are divided in skeletal and dental ones, and among the latter, Olze's method is one of the most recent, since it was introduced in 2010 with the aim to identify the legal age of 18 and 21 years by evaluating the different stages of development of the periodontal ligament of the third molars with closed root apices. The present study aims at verifying the applicability of the method to the daily forensic practice, with special focus on the interobserver repeatability. Olze's method was applied by three different observers (two physicians and one dentist without a specific training in Olze's method) to 61 orthopantomograms from subjects of mixed ethnicity aged between 16 and 51 years. The analysis took into consideration the lower third molars. The results provided by the different observers were then compared in order to verify the interobserver error. Results showed that interobserver error varies between 43 and 57 % for the right lower third molar (M48) and between 23 and 49 % for the left lower third molar (M38). Chi-square test did not show significant differences according to the side of teeth and type of professional figure. The results prove that Olze's method is not easy to apply when used by not adequately trained personnel, because of an intrinsic interobserver error. Since it is however a crucial method in age determination, it should be used only by experienced observers after an intensive and specific training.

  12. [Relationship among the eruption of the first temporal teeths, the breast feeding duration and the anthropometric development in the first two years of life].

    PubMed

    Martín Moreno, V; Molina Cabrerizo, M R; Gómez Gómez, C

    2006-01-01

    The anthropometric development in the first two years of life can be influenced by diverse factors, being analyzed in this study the implication of the primary tooth eruption and the breast feeding duration in this development. Longitudinal study. 141 healthy children participated (67 boys and 74 girls), being analyzed the association among the duration of breast feeding, the number of teeth present at the 6, 7, 9 and 12 months, the anthropometrics parameters weight, height and body mass index (BMI) to the birth, 1-7, 9, 12, 15, 18 and 24 months and the growth rate. The weight and height at the birth or the duration of breast feeding didn't associate significantly with the weight and height at the 2 years or the number of teeth at 6,7,9 or 12 months, but the women with more weight (r = 0,366) and height (r = 0,377) at month of life have a bigger number of teeth at 9 months (p = 0,001). In both sexes, the number of teeth at the 9 months are associated significantly with the weight (boys r = 0,328, p = 0,01; girls r = 0,307, p = 0,011) and height (r = 0,352 boys and girls p = 0,005) at two years. In healthy children the duration of maternal nursing doesn't influence in the degree of anthropometric development reached at 2 years, but yes makes it the number of teeth present at 9 months, result that suggests that the eruption dental early could suppose an evolutive advantage.

  13. Method of control position of laser focus during surfacing teeth of cutters

    NASA Astrophysics Data System (ADS)

    Zvezdin, V. V.; Hisamutdinov, R. M.; Rakhimov, R. R.; Israfilov, I. H.; Akhtiamov, R. F.

    2017-09-01

    Providing the quality laser of surfacing the edges of teeth requires control not only the energy of the radiation parameters, but also the position of the focal spot. The control channel of position of laser focus during surfacing, which determines the parameters of quality of the deposited layer, was calculated in the work. The parameters of the active opto-electronic system for the subsystem adjust the focus position relative to the deposited layer with a laser illumination of the cutting edges the teeth cutters were calculated, the model of a control channel based on thermal phenomena occurring in the zone of surfacing was proposed.

  14. Supernumerary teeth: Report of four unusual cases

    PubMed Central

    Kumar, Arun; Namdev, Ritu; Bakshi, Lokesh; Dutta, Samir

    2012-01-01

    Supernumerary tooth denotes duplication of tooth in the normal series. It is a developmental anomaly and has been argued to arise from multiple etiologies. These teeth may remain embedded in the alveolar bone or can erupt into the oral cavity. The supernumerary tooth might cause esthetic and/or functional problems, especially if it is situated in the maxillary anterior region. Complications reported were delayed or prevented eruption of succedaneous teeth, displacement or rotation, crowding of the affected region, abnormal diastema, dilacerations, cystic formation, and sometime eruption into the nasal cavity. In this case report, four unusual cases of supernumerary teeth that resulted in varying degrees of disturbances in permanent dentition are presented. Conservative surgical intervention and light orthodontic forces were used to bring the teeth into normal position with minimal disturbance to the surrounding oral structures. PMID:22629072

  15. Variations in the anatomical positioning of impacted mandibular wisdom teeth and their practical implications.

    PubMed

    Schneider, Thomas; Filo, Katharina; Kruse, Astrid L; Locher, Michael; Grätz, Klaus W; Lübbers, Heinz-Theo

    2014-01-01

    Surgical removal of impacted third molars is one of the most frequent procedures in oral surgery. Here, three-dimensional (3D) imaging is often used, yet its necessity is still being heavily debated. The aim of the study was to describe the variation in the anatomical positioning of third mandibular molars, and, by doing so, examine the necessity of 3D imaging. A retrospective case study was performed with the patients from an oral surgery department from January 2009 to February 2013. The primary focus of the study was on the spatial relationship to the mandibular canal, as well as angulation, root configuration, and developmental stage of the wisdom tooth. Descriptive statistics were calculated for these variables. A total of 1197 wisdom teeth in 699 patients were evaluated. 46.7% exhibited direct contact to the mandibular canal, another 28.7% showed close proximity and 24.6% a measurable distance. In 29.0%, the mandibular canal was vestibular and in 23.8% lingual to the wisdom tooth. In 7.4%, it was interradicular and in 0.6% intraradicular. Most teeth had one (21.3%) or two (55.3%) roots. Others had three (17.6%), four (2.0%) or five (0.2%) roots. In 31.4% of the teeth, the root perforated the lingual compact bone, and in 4.3% the vestibular compact bone. 44.4% of the teeth had mesial angulation, 9.7% distal angulation, 35.3% lingual and 2.9% buccal angulation. Due to the anatomical variety, the use of 3D imaging is recommended before surgical removal of mandibular third molars if conventional imaging cannot exclude complicated conditions.

  16. Position of lower wisdom teeth and their relation to the alveolar nerve in orthodontic patients treated with and without extraction of premolars: a longitudinal study.

    PubMed

    Miclotte, Annelie; Van Hevele, Jeroen; Roels, Ann; Elaut, Jürgen; Willems, Guy; Politis, Constantinus; Jacobs, Reinhilde

    2014-09-01

    The present longitudinal study aimed to compare changes in the lower third molar position and nerve involvement in orthodontically treated patients with and without premolar extractions. The sample consisted of pretreatment and posttreatment panoramic radiographs of 349 orthodontically treated patients subdivided into a non-extraction group (n = 263) and an extraction group (n = 86). Patients did not present dental agenesis in the lower jaw. The mandibular third molar position was assessed by classifying the teeth according to Pell and Gregory, Winter, and two new classifications. The relation between third molars and the mandibular canal was assessed based on Whaites' classification. The development of third molars was evaluated based on Demirjian's classification. Data were analyzed using frequency analysis, Mann-Whitney U test, Fisher's exact test, and chi-square testing. There was a significant difference (p < 0.05) in eruption space between pretreatment and posttreatment panoramic radiographs for both groups. For pretreatment panoramic radiographs, chi-square tests revealed no significant differences between both groups. For posttreatment panoramic radiographs, significant differences appeared for extraction versus non-extraction patients for Pell and Gregory horizontal classification, Winter's classification, and a potential relationship between third molars and the alveolar nerve (p < 0.05). Orthodontic treatment without premolar extractions shows significantly more eruption problems of wisdom teeth than those with premolar extractions. Third molars in the non-extraction group were more frequently found in close relationship to the mandibular nerve compared to the extraction group. Orthodontists should be aware of the effect of orthodontic treatment on the development of the lower third molars.

  17. Impacted Wisdom Teeth

    MedlinePlus

    ... to appear (erupt) in the mouth. Sometimes a wisdom tooth becomes stuck below the surface of your gums ( ... t always cause symptoms. However, when an impacted wisdom tooth becomes infected, damages other teeth or causes other ...

  18. Surgical repositioning of a developing maxillary permanent central incisor in a horizontal position: spontaneous eruption and root formation.

    PubMed

    Kuroe, Kazuto; Tomonari, Hiroshi; Soejima, Kazuhisa; Maeda, Aya

    2006-06-01

    This report describes the surgical repositioning of a developing maxillary permanent central incisor in a horizontal position, followed by spontaneous eruption and root formation without orthodontic traction. Surgical exposure of the right central incisor was achieved. A 7-year-old boy referred for orthodontic consultation. Radiographic examination showed the crown of a maxillary right central incisor to be positioned horizontally with root formation at the initial stage. The surgically repositioned incisor (by a close-eruption surgical flap technique) spontaneously erupted into correct alignment after 2 years 3 months. The erupted incisor remained vital and responded normally to percussion, mobility and sensitivity testing. The soft tissue, periodontal attachment, gingival contour and probing depths were normal. Follow-up radiographs confirmed the continued development of the root, with revascularization of the pulp and a normal appearance of the periodontal space and lamina dura. There was, however, shorter root formation and a narrower root cavity compared with the contralateral incisor. As a result, no orthodontic traction and alignment were required. This method of surgical repositioning is a viable alternative to the traditional approach of extraction or surgical exposure followed by orthodontic traction for a developing maxillary permanent central incisor in a horizontal position.

  19. Effects of vertical positions of anterior teeth on smile esthetics in Japanese and korean orthodontists and orthodontic patients.

    PubMed

    Ioi, Hideki; Kang, Sangwook; Shimomura, Takahiro; Kim, Seong-Sik; Park, Soo-Byung; Son, Woo-Sung; Takahashi, Ichiro

    2013-08-01

    The perception of a pleasing smile may differ between the countries in Asia or may be converging on a more internationally pleasing one. The aim of this study was to evaluate the influence of vertical positions of anterior teeth on smile esthetics as assessed by Japanese and Korean orthodontists as well as by orthodontic patients. A standard composite smile was constructed from different females' intraoral and extraoral photographs. Vertical positions of anterior teeth were modified digitally in 1-mm increments, from 5 mm upper lip coverage of the incisors to 5 mm gingival exposure. Using a visual analog scale, 41 Japanese orthodontists and 96 Japanese orthodontic patients, 25 Korean orthodontists, and 72 Korean orthodontic patients rated the attractiveness of 11 smiles with altered gingival displays. Overall, the Japanese and Korean raters assigned similar esthetic scores between the corresponding groups. The male orthodontic patients assigned higher scores to the smiles with upper lip coverage of the teeth than the corresponding females did in both countries. The female patients assigned clinically significant higher scores to the smiles from 2 mm upper lip coverage of the teeth to 0 mm gingival exposure in both countries. In both countries, the orthodontists and the female patients shared the similar preference in the smile evaluation of vertical positions of anterior teeth, whereas the male orthodontic patients were more tolerant of upper lip coverage of the anterior teeth than the orthodontists and the female patients. This study proposes 0 mm to 2 mm of upper lip coverage of the teeth as a threshold of acceptability for esthetic smile evaluations in female orthodontic patients. For male orthodontic patients, the paper proposes negative gingival display as a threshold of acceptability for esthetic smile evaluations. © 2013 Wiley Periodicals, Inc.

  20. The value of the Gothic arch tracing in the positioning of denture teeth.

    PubMed

    el-Gheriani, A S; Winstanley, R B

    1988-07-01

    Twenty-five subjects of three nationalities carried out Gothic arch tracings. Measurements between the side arms were compared with the upper intercuspid distances measured in the same subjects. A relationship was found which may be of value in the setting up of anterior maxillary denture teeth.

  1. A preliminary study for determination of three-dimensional root apex position of the maxillary teeth using camera calibration technology.

    PubMed

    Oh, Hyun Jun; Yang, Il-Hyung; Baek, Seung-Hak

    2016-01-01

    To propose a novel method for determining the three-dimensional (3D) root apex position of maxillary teeth using a two-dimensional (2D) panoramic radiograph image and a 3D virtual maxillary cast model. The subjects were 10 adult orthodontic patients treated with non-extraction. The multiple camera matrices were used to define transformative relationships between tooth images of the 2D panoramic radiographs and the 3D virtual maxillary cast models. After construction of the root apex-specific projective (RASP) models, overdetermined equations were used to calculate the 3D root apex position with a direct linear transformation algorithm and the known 2D co-ordinates of the root apex in the panoramic radiograph. For verification of the estimated 3D root apex position, the RASP and 3D-CT models were superimposed using a best-fit method. Then, the values of estimation error (EE; mean, standard deviation, minimum error and maximum error) between the two models were calculated. The intraclass correlation coefficient values exhibited good reliability for the landmark identification. The mean EE of all root apices of maxillary teeth was 1.88 mm. The EE values, in descending order, were as follows: canine, 2.30 mm; first premolar, 1.93 mm; second premolar, 1.91 mm; first molar, 1.83 mm; second molar, 1.82 mm; lateral incisor, 1.80 mm; and central incisor, 1.53 mm. Camera calibration technology allows reliable determination of the 3D root apex position of maxillary teeth without the need for 3D-CT scan or tooth templates.

  2. Wisdom teeth: mankind's future third vice-teeth?

    PubMed

    Zou, DuoHong; Zhao, Jun; Ding, WangHui; Xia, LunGuo; Jang, XinQuan; Huang, YuanLiang

    2010-01-01

    The third molar teeth (wisdom teeth) represent the last eruption of the teeth in the human dentition. Throughout evolution, the mandible has had a tendency to decrease in size; the third molar teeth are often impacted, resulting in incomplete tooth eruption that often causes clinical pericoronitis, dental caries, and pericemental abscess. Therefore, the wisdom teeth are often extracted. Moreover, wisdom teeth are often removed for clinical orthodontic treatment. On the other hand, tooth loss due to periodontal disease, dental caries, trauma, or a variety of genetic disorders continues to affect people's lives. Autologous tissues for dental tissue regeneration that could replace lost teeth could provide a vital alternative to currently available clinical treatments. To pursue this goal, we hypothesize that human third molar tooth buds can be obtained during development. Human wisdom tooth germination tissue could then be placed into an embryonic stem cell bank for storage. When the donor's other teeth are missing, embryonic stem cell and tissue engineering technologies, will permit the restoration of the missing teeth. Therefore wisdom teeth will be mankind's future third vice-teeth.

  3. [Natal and neonatal teeth].

    PubMed

    Baumgart, Manuela; Lussi, Adrian

    2006-01-01

    Natal teeth have been defined as teeth which are present at birth, while neonatal teeth erupt during the first 30 days. Their occurrence is rare, the prevalence ranges from 1:2000 to 1:3000 with a higher frequency in the lip and palate clefts and syndroms. In about 85% natal or neonatal teeth are lower central incisors (60% in pairs), rare are upper teeth, molars and multiple teeth. In almost 90% they are part of the deciduous dentition. A lot of possible causes of early eruption are discussed, but only the relation to hereditary factors seems to be evident. An autosomal dominant trait is often described. The appearance of these teeth is dependent on the degree of maturity, but most of the time it is loose, small, discoloured and hypoplastic. Histologically, enamel hypoplasia with normal prism structure is apparent. No significant disturbances of the dentin structures are observed, only cervically dentin becomes atubular with spaces and enclosed cells. A large vascular pulp and failure of root formation are further investigations. Our microhardness measurements showed values from 24.3-32.4 KHN for enamel and 48.3-62.2 KHN for dentin, while normal deciduous teeth have an enamel hardness of 322.0 +/- 17.5 KHN. The thickness of enamel was never more than 280 microm compared to up to 1200 microm in normal teeth. This shows the retarded development of natal and neonatal teeth, because mineralization has not finished at the time of birth. In accordance with developmental age tooth structure and appearence are normal. In consideration of complications as Riga-Fede-disease, feeding problems, possibility of infection and hypermobility most of the time extraction is the treatment of choice, but in the interest of protecting the child this decision should be made carefully.

  4. Management of an infant having natal teeth

    PubMed Central

    Khandelwal, Vishal; Nayak, Ullal Anand; Nayak, Prathibha Anand; Bafna, Yash

    2013-01-01

    Eruption of teeth at or immediately after birth is a relatively rare phenomenon. These teeth are known as ‘natal’ teeth if present at birth and ‘neonatal’ teeth if they erupt during the first 30 days of life. Natal teeth might resemble normal primary dentition in size and shape; however, the teeth are often smaller, conical and yellowish and have hypoplastic enamel and dentin with poor or absent root formation. Complications include difficulty and discomfort during suckling, sublingual ulceration, laceration of the mother’s breasts and aspiration of the teeth. These situations would warrant extraction. If the tooth does not interfere with breast feeding and is otherwise asymptomatic, no treatment is necessary. Negative cultural attitudes towards natal teeth demand good parental counselling and vigilant management in relation to child protection. Both general practice dentists and paediatric dental specialists may be involved in the supervision or treatment of patients with natal and neonatal teeth. PMID:23737593

  5. Characteristics of premaxillary supernumerary teeth in primary and mixed dentitions: a retrospective analysis of 212 cases.

    PubMed

    Shekhar, Madiraju G

    2012-08-01

    To investigate the characteristics and distribution of premaxillary supernumerary teeth affecting primary and mixed dentitions in Indian children. This retrospective analysis included 11 200 children, aged 3-12 years, who attended a pediatric dental clinic for dental care during the period 2007-2010. The children were divided into group I (aged 3-6 years) and group II (aged 7-12 years), and data regarding maxillary anterior supernumerary teeth, diagnosed both as isolated and/or as unexpected findings during routine clinical and radiological examinations, were gathered. Pearson's χ(2) -test, with a 0.05 level of significance, was used for the analysis. The overall prevalence of premaxillary supernumerary teeth in primary and mixed dentitions was 1.9%. Single supernumerary teeth (84.9%) and conical morphology (68.7%) were commonly seen in both groups. The most common sagittal position was palatal (92.3%) among both erupted and impacted maxillary anterior supernumerary teeth. The prevalence of premaxillary supernumerary teeth in Indian children found in this study was 1.9%, with an overall male to female ratio of 1.7:1. Single supernumerary teeth, conical morphology, and erupted supernumerary teeth were the most commonly seen. Supernumerary teeth associated with clinical complications were relatively low (48%), and axial rotation or displacement of maxillary incisors was the most common sequelae. © 2012 Blackwell Publishing Asia Pty Ltd.

  6. Fast and Early Mandibular Osteodistraction: The Long-Term Follow-Up of Mandibular Distraction Osteogenesis on Teeth Position.

    PubMed

    Cascone, Piero; Basile, Emanuela; Saccucci, Matteo; Di Carlo, Gabriele; Angeletti, Diletta; Ramieri, Valerio; Polimeni, Antonella

    2015-11-01

    Pierre Robin Sequence is a congenital pathology defined by the triad micrognathia, glossoptosis and often a U-shaped cleft of soft palate. Newborns affected by airways obstruction may necessitate more invasive options: tongue-lip adhesion, tracheostomy and mandibular distraction osteogenesis. The authors analyzed the effect of fast and early mandibular osteodistraction on deciduous dental development in patients affected by Pierre Robin Sequence. Analysis of the patients treated for severe form was performed by a team composed by maxillofacial surgeons and dentists. Five patients were included for the analysis: before and long term clinical and radiological assessments were considered. All patients underwent fast and early mandibular osteodistraction; two years follow up computed tomography and panorex reconstructions showed bone consolidation, 33 of 35 teeth analyzed before ostedistraction are present after distraction protocol; no positional changes were detected at the follow up analysis either deciduous teeth and molar permanent buds. No deformities regarding molar buds were detected. In conclusion external mandibular distractor devices have been associated with dental injuries and facial scaring. Even though, the dental complications identified can not be unambiguously connected to the external distractor devices.

  7. The effects of alveolar bone loss and miniscrew position on initial tooth displacement during intrusion of the maxillary anterior teeth: Finite element analysis

    PubMed Central

    Cho, Sun-Mi; Choi, Sung-Hwan; Sung, Sang-Jin; Yu, Hyung-Seog

    2016-01-01

    Objective The aim of this study was to determine the optimal loading conditions for pure intrusion of the six maxillary anterior teeth with miniscrews according to alveolar bone loss. Methods A three-dimensional finite element model was created for a segment of the six anterior teeth, and the positions of the miniscrews and hooks were varied after setting the alveolar bone loss to 0, 2, or 4 mm. Under 100 g of intrusive force, initial displacement of the individual teeth in three directions and the degree of labial tilting were measured. Results The degree of labial tilting increased with reduced alveolar bone height under the same load. When a miniscrew was inserted between the two central incisors, the amounts of medial-lateral and anterior-posterior displacement of the central incisor were significantly greater than in the other conditions. When the miniscrews were inserted distally to the canines and an intrusion force was applied distal to the lateral incisors, the degree of labial tilting and the amounts of displacement of the six anterior teeth were the lowest, and the maximum von Mises stress was distributed evenly across all the teeth, regardless of the bone loss. Conclusions Initial tooth displacement similar to pure intrusion of the six maxillary anterior teeth was induced when miniscrews were inserted distal to the maxillary canines and an intrusion force was applied distal to the lateral incisors. In this condition, the maximum von Mises stresses were relatively evenly distributed across all the teeth, regardless of the bone loss. PMID:27668194

  8. Teeth in the line of mandibular fractures.

    PubMed

    Chrcanovic, Bruno Ramos

    2014-03-01

    This study aims to review the literature regarding the evolution of current thoughts on the management of teeth in the line of mandibular fractures (MFs). An electronic search in PubMed was undertaken in June 2012. The titles and abstracts from these results were read to identify studies within the selection criteria-studies reporting clinical series of MFs in which the management of teeth in the fracture line was analyzed. The search strategy initially yielded 731 references. Twenty-seven studies were identified without repetition within the selection criteria. Additional hand searching yielded 12 additional papers. It is suggested that rigid fixation systems and the use of antimicrobial agents have reduced the incidence of infection in cases of teeth in the line of MFs. Tooth buds in the line of MFs should not be removed or replaced in the (alleged) proper position despite the degree of displacement, since studies showed that even tooth buds in the early stage of calcification and those involved in widely displaced fracture sites continued development and erupted. Its removal should be considered in cases of infection, which is a predictive factor of abnormality and/or impaction. Intact teeth in the fracture line should be left in situ if they show no evidence of severe loosening or inflammatory change. Permanent teeth maintained in the line of fracture should be followed up clinically and radiographically for at least 1 year to ensure that any unnecessary endodontic treatment is avoided. Teeth in the line of fracture that prevents reduction of fractures, teeth with fractured roots, a partially impacted wisdom tooth with pericoronitis, and a tooth with extensive periapical lesion should be removed. Teeth in the line of MFs should also be removed when located in sites where there is extensive periodontal damage, with broken alveolar walls, resulting in the formation of a deep pocket (making optimal healing doubtful).

  9. Natal teeth in premature dizygotic twin girls

    PubMed Central

    Dahake, Prasanna T; Shelke, Anup U; Kale, Yogesh J; Iyer, Vidya Vijay

    2015-01-01

    Presence or eruption of teeth immediately at or after birth is a rarely reported phenomenon. This condition is referred to as natal teeth, neonatal teeth, congenital teeth, fetal teeth, predeciduous teeth and dentitia praecox. The most affected teeth are lower primary central incisors with the incidence of 1:2000 for natal and 1:3500 for neonatal teeth. The aetiology of this anomaly is still not clear, however, attributes have been reported in relation to congenital teeth, multiple factors and some syndromes. The management of such cases depends on clinical characteristics of natal or neonatal teeth, as well as complications that they might cause. The aim of this paper is to discuss a rare case of occurrence of two natal teeth in both premature dizygotic twin female babies with specific emphasis on the literature review related to concerns regarding prevalence, aetiology, clinical characteristics, differential diagnosis, complications and management. PMID:26682836

  10. Effect of retraction of anterior teeth on pharyngeal airway and hyoid bone position in Class I bimaxillary dentoalveolar protrusion.

    PubMed

    Bhatia, S; Jayan, B; Chopra, S S

    2016-12-01

    To test the hypothesis that the retraction of anterior teeth has no effect on the dimensions of pharyngeal airway and to evaluate the retraction of anterior teeth on each parameter of pharyngeal airway. Twenty-two adult patients of Class I bimaxillary protrusion requiring first premolar extractions with maximum anchorage requirements were selected. The pharyngeal airway and dentofacial parameters of the patients were compared using pre- and post-treatment lateral cephalograms with the help of Student's paired t -test ( P  < 0.05). The relationship between airway size and dentofacial parameters was also evaluated using Pearson correlation coefficient. The upper and lower lips were retracted by 2.25 and 5.4 mm after retraction of the incisors. The tips of upper and lower incisors were retracted by 7.75 and 7.15 mm, respectively. There was a statistically significant decrease in SPP-SPPW ( P  < 0.05), U-MPW ( P  < 0.001), TB-TPPW ( P  < 0.001), and change in HRGN ( P  < 0.01). A significant correlation was observed between the amount of retraction of lower incisor and decrease in the pharyngeal airway posterior to soft palate ( r  = 0.102), tongue ( r  = 0.322), and change in HRGN ( r  = 0.265). The size of the pharyngeal (velopharyngeal and glossopharyngeal) airway reduced and hyoid bone position changed after retraction of the incisors in extraction space in bimaxillary protrusive adult patients.

  11. Acute Skin Eruptions That Are Positive for Herpes Simplex Virus DNA Polymerase in Patients With Stem Cell Transplantation

    PubMed Central

    Burnett, Joseph W.; Laing, Jennifer M.; Aurelian, Laure

    2013-01-01

    Background Patients with stem cell transplantation (SCT) develop erythematous eruptions (SCTE) that are often misdiagnosed and poorly treated. Latent herpes simplex virus (HSV) is likely to be reactivated by SCT-associated immunosuppression. Therefore, one of the differential diagnostic possibilities for SCTE is HSV-associated erythema multiforme (HAEM) in which HSV genetic fragments localize in stem cells that deliver them to the skin on differentiation. Observations Lesional skin from patients with SCTE, HAEM, HSV, or drug-induced erythema (DIEM) was stained with antibodies to the HSV antigen DNA polymerase (Pol) and the major capsid protein, virion protein 5 (VP5). The HSV DNA polymerase Pol was expressed in 79% of patients with SCTE and 75% of those with HAEM. The protein VP5 was not expressed in these patients, indicative of the absence of virus replication. Findings in patients with DIEM were negative for both antigens, and those with HSV lesions were positive for both antigens. Conclusions There is a growing problem with SCTE, related to the increasing numbers of performed SCT. The greater frequency of SCT-generated circulating stem cells in patients with hematological malignant neoplasms (who have latent HSV infection) may result in a widespread SCTE characterized by skin deposition of HSV DNA fragments, notably those expressing Pol antigen. This HAEM-like presentation should be considered in the differential diagnosis of SCTE. Prolonged high-dosage antiviral chemotherapy during and after hospitalization may be warranted. PMID:18645142

  12. Laser fluorescence in monitoring the influence of targeted tooth brushing on remineralization of initial caries lesions on newly erupted molar teeth - RCT.

    PubMed

    Laitala, M-L; Jaanti, E; Vähänikkilä, H; Määttä, T; Heikka, H; Hausen, H; Anttonen, V

    2017-11-01

    This study aimed to monitor mineralization changes in initial caries lesions on newly erupted second molars using laser fluorescence (LF) scanning after a 1-month targeted tooth brushing intervention. Altogether, 124 13- to 14-year-old school children were invited to participate. Of those who fulfilled the clinical criteria (at least one initial lesion with LF value >10 in second molars), 51 gave their written consent to participate. Laser fluorescence values were registered at baseline and after 1-month follow-up period. All participants were individually taught targeted tooth brushing of their second molars and randomly provided tooth paste with 0 or 1500 ppm fluoride. Brushing frequency was investigated at baseline and after the follow-up. Change in LF values was compared considering the tooth, content of fluoride in the paste and brushing frequency. In lesions with LF values ≤30 at baseline, change in LF values demonstrated improvement. Improvement was detected especially in upper molars. In lesions with LF values >30 at baseline, improvement was least detected. Brushing frequency increased slightly during the intervention. Laser fluorescence is a simple method and useful in monitoring remineralization of incipient lesions even in weeks. Targeted tooth brushing seems to induce remineralization even in weeks. Laser fluorescence could be a valuable motivating tool in promoting patients' self-care. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  13. Dental eruption in afrotherian mammals

    PubMed Central

    Asher, Robert J; Lehmann, Thomas

    2008-01-01

    Background Afrotheria comprises a newly recognized clade of mammals with strong molecular evidence for its monophyly. In contrast, morphological data uniting its diverse constituents, including elephants, sea cows, hyraxes, aardvarks, sengis, tenrecs and golden moles, have been difficult to identify. Here, we suggest relatively late eruption of the permanent dentition as a shared characteristic of afrotherian mammals. This characteristic and other features (such as vertebral anomalies and testicondy) recall the phenotype of a human genetic pathology (cleidocranial dysplasia), correlations with which have not been explored previously in the context of character evolution within the recently established phylogeny of living mammalian clades. Results Although data on the absolute timing of eruption in sengis, golden moles and tenrecs are still unknown, craniometric comparisons for ontogenetic series of these taxa show that considerable skull growth takes place prior to the complete eruption of the permanent cheek teeth. Specimens showing less than half (sengis, golden moles) or two-thirds (tenrecs, hyraxes) of their permanent cheek teeth reach or exceed the median jaw length of conspecifics with a complete dentition. With few exceptions, afrotherians are closer to median adult jaw length with fewer erupted, permanent cheek teeth than comparable stages of non-afrotherians. Manatees (but not dugongs), elephants and hyraxes with known age data show eruption of permanent teeth late in ontogeny relative to other mammals. While the occurrence of delayed eruption, vertebral anomalies and other potential afrotherian synapomorphies resemble some symptoms of a human genetic pathology, these characteristics do not appear to covary significantly among mammalian clades. Conclusion Morphological characteristics shared by such physically disparate animals such as elephants and golden moles are not easy to recognize, but are now known to include late eruption of permanent teeth, in

  14. Size, ultrastructure, and microhardness of natal teeth with agenesis of permanent successors.

    PubMed

    Stamfelj, Iztok; Jan, Janja; Cvetko, Erika; Gaspersic, Dominik

    2010-08-20

    Natal and neonatal teeth may occur in conjunction with other oral anomalies, including anomalous development of succedaneous teeth. Our purpose was to examine the size, ultrastructure, and microhardness of two natal teeth without permanent successor germs, and compare them with the characteristics of normal primary teeth. The dimensions of two natal mandibular incisors extracted from a healthy 7-year-old child were measured with a digital sliding caliper. The crown dimensions of normal primary mandibular central incisors were established from dental casts of 102 children. Since the natal teeth were nearly completely devoid of enamel, the average enamel thickness determined on a sample of 19 normal primary mandibular incisors was added to the values measured. External surfaces and transverse sections of the natal teeth were examined under a scanning electron microscope. Vickers microhardness of radicular dentine was assessed for the natal teeth and for 11 normal primary mandibular incisors. Only remnants of enamel were present. All crown dimensions corrected for enamel loss were within the normal range. The ultrastructure of hard dental tissues was normal. The radicular dentine hardness of the natal teeth was similar to that of the normal primary mandibular incisors. The results indicate that the natal teeth were prematurely erupted regular primary mandibular central incisors. In our case, the occurrence of natal teeth associated with agenesis of their primary successors appears to be related to an accelerated or premature pattern of dental development, rather than to superficial positioning of the tooth germs. 2010 Elsevier GmbH. All rights reserved.

  15. Size of tooth crowns and position of teeth concerning the extension of facial plexiform neurofibroma in patients with neurofibromatosis type 1.

    PubMed

    Friedrich, Reinhard E; Giese, Manfred; Stelljes, Claudia; Froeder, Christine; Scheuer, Hanna A

    2012-05-01

    Neurofibromatosis type 1 (NF1) is an autosomal dominant inherited tumour syndrome. NF1 is also a disorder of bone in terms of altered bone metabolism and bone dysplasia. Facial plexiform neurofibroma (PNF) is frequently associated with osseous alterations and may cause severe disfigurement. These PNFs regularly affect the oral cavity and teeth. PNF pose many problems in reconstructive and oral surgery. This study was undertaken to describe oral findings related to PNFs and to investigate the size and position of teeth in these tumours. Forty-eight patients with NF1 were investigated. Tumour type was histologically proven in all patients with PNF following aesthetic/functional orofacial surgery. Twenty-four patients were affected with a PNF and 24 had disseminated cutaneous neurofibroma (DCNF). In the PNF group, the side of the PNF was registered; PNF was unilateral in all cases. DCNF patients were 15 females and 9 males (mean age: 23.92±10.48 years, minimum: 6, maximum 45 years). Patients with PNF were 17 males and 7 females (mean age: 23.92±13.76 years, minimum 6, maximum 61 years). The right side was affected in 16 and the left in 8 PNF patients. All patients were orally investigated and dental casts were obtained. Distances of the alveolar processes and of the teeth were measured in transverse and sagittal planes. In order to evaluate the possible impact of the tumour localisation inside the trigeminal nerve, the topography of the affected facial areas was assigned to the trigeminal nerve branches. Radiographs were taken to asses the formation of dental roots, to reveal retained teeth and to estimate dysplastic areas of the jaws. The size of tooth crowns did not differ from published standards on tooth parameters of Caucasian individuals. The dental arches were symmetrically arranged in all patients of the DCNF group. However, the position of teeth showed some relevant differences in the PNF group. We observed spacing between teeth, probably due to interdental

  16. A 12-month clinical evaluation of pit-and-fissure sealants placed with and without etch-and-rinse and self-etch adhesive systems in newly-erupted teeth

    PubMed Central

    NOGOURANI, Maryam Karami; JANGHORBANI, Mohsen; KHADEM, Parvin; JADIDI, Zahra; JALALI, Shahriar

    2012-01-01

    Objectives The objective of this one-year clinical study was to investigate the effect of two adhesive systems (Adper Single Bond, a two-step etch-and-rinse and Clearfil SE Bond, a two-step self-etch system) on pit-and-fissure sealant retention in newly-erupted teeth. This study compared the success of the sealants in mesial and distopalatal grooves with and without these two adhesive systems. Material and Methods In a clinical trial, 35 children aged 6-8 years undergoing sealant placement were recruited. This one-year clinical study scored 70 mesial and 70 distopalatal sealants of newly-erupted permanent maxillary first molar, with a split-mouth design. All children received sealant alone in one permanent maxillary molar tooth. Children were randomized into two groups. One group received Self-Etch (SE) bond plus sealant and the other group received Single Bond plus sealant in another permanent maxillary molar tooth. Clinical evaluation at 3, 6 and 12 months was performed and the retention was studied in terms of the success and failure. Results The success rate of sealant in the distopalatal groove, using SEB at 3, 6 and 12 months was 93.3% (95% CI: 68.0, 99.8), 73.3% (95% CI: 44.9, 92.2) and 66.7% (95% CI: 38.4, 88.2), respectively. It was greater than that of the distopalatal groove in SB group with a success rate of 62.5% (95% CI: 35.4, 84.8), 31.3% (95% CI: 11.8, 58.7) and 31.3% (95% CI: 11.8, 58.7), at the three evaluation periods. The success rate of sealant in the mesial groove using SEB was 86.6% (95% CI: 59.5, 98.3), 53.3% (95% CI: 26.6, 78.7) and 53.3% (95% CI: 26.6, 78.7), while this was 100% (95% CI: 79.4, 100.0), 81.3% (95% CI: 54.4, 96.0) and 81.3% (95% CI: 54.4, 96.0) using SB, at 3, 6 and 12-month evaluation periods. Conclusions These results support the use of these two bonding agents in pit-and-fissure sealants under both isolated and contaminated conditions. Further, SE bond seemed to be less sensitive to moisture contamination. PMID:22858703

  17. A 12-month clinical evaluation of pit-and-fissure sealants placed with and without etch-and-rinse and self-etch adhesive systems in newly-erupted teeth.

    PubMed

    Nogourani, Maryam Karami; Janghorbani, Mohsen; Khadem, Parvin; Jadidi, Zahra; Jalali, Shahriar

    2012-01-01

    The objective of this one-year clinical study was to investigate the effect of two adhesive systems (Adper Single Bond, a two-step etch-and-rinse and Clearfil SE Bond, a two-step self-etch system) on pit-and-fissure sealant retention in newly-erupted teeth. This study compared the success of the sealants in mesial and distopalatal grooves with and without these two adhesive systems. In a clinical trial, 35 children aged 6-8 years undergoing sealant placement were recruited. This one-year clinical study scored 70 mesial and 70 distopalatal sealants of newly-erupted permanent maxillary first molar, with a split-mouth design. All children received sealant alone in one permanent maxillary molar tooth. Children were randomized into two groups. One group received Self-etch (Se) bond plus sealant and the other group received Single Bond plus sealant in another permanent maxillary molar tooth. Clinical evaluation at 3, 6 and 12 months was performed and the retention was studied in terms of the success and failure. The success rate of sealant in the distopalatal groove, using SeB at 3, 6 and 12 months was 93.3% (95% CI: 68.0, 99.8), 73.3% (95% CI: 44.9, 92.2) and 66.7% (95% CI: 38.4, 88.2), respectively. It was greater than that of the distopalatal groove in SB group with a success rate of 62.5% (95% CI: 35.4, 84.8), 31.3% (95% CI: 11.8, 58.7) and 31.3% (95% CI: 11.8, 58.7), at the three evaluation periods. The success rate of sealant in the mesial groove using SeB was 86.6% (95% CI: 59.5, 98.3), 53.3% (95% CI: 26.6, 78.7) and 53.3% (95% CI: 26.6, 78.7), while this was 100% (95% CI: 79.4, 100.0), 81.3% (95% CI: 54.4, 96.0) and 81.3% (95% CI: 54.4, 96.0) using SB, at 3, 6 and 12-month evaluation periods. These results support the use of these two bonding agents in pit-and-fissure sealants under both isolated and contaminated conditions. Further, Se bond seemed to be less sensitive to moisture contamination.

  18. About Kids' Teeth

    MedlinePlus

    ... Kids’ Teeth Teeth Helpful Resources Links About Kids’ Teeth We have two sets of teeth during life: ... usually appeared. Learn about Nutrition Baby Teething Baby Teeth and Teething Baby teeth usually appear when your ...

  19. Investigation of impacted supernumerary teeth: a cone beam computed tomograph (cbct) study.

    PubMed

    Gurler, Gokhan; Delilbasi, Cagri; Delilbasi, Evren

    2017-01-01

    The purpose of this study was to investigate the impacted supernumerary teeth which were initially detected on panoramic radiographs by using cone beam computed tomography (CBCT). In this retrospective study, supernumerary teeth diagnosed on panoramic radiographs taken from patients who had admitted for routine dental treatment were evaluated using CBCT. Patients' age, gender, systemic conditions as well as number of supernumerary teeth, unilateral-bilateral presence, anatomical localization (maxilla, mandible, anterior-premolar-molar, mesiodens-lateral-canine, parapremolar-paramolar-distomolar) shape (rudimentary, supplemental, tuberculate, odontoma), position (palatal-lingual-buccal-labial-central), shortest distance between the tooth and adjacent cortical plate, complications and treatment were assessed. A total of 47 impacted supernumerary teeth in 34 patients were investigated in this study. Of these, 33 (70.2%) were unilateral and 14 (29.8%) were bilateral. Only 1 supernumerary tooth was found in 27 patients (79.4%) whereas 7 patients (20.6%) had 2 or more supernumerary teeth. Most of the teeth located in the anterior region (74.4%) of the jaws and maxilla (74.4%). Twenty teeth (42.5%) were mesiodens, 11 (23.4%) were lateral or canine, 14 (29.7%) were parapremolar and 2(4.4%) were distomolar. Twenty-seven teeth (57.4%) were rudimentary, 15 (31.9%) were supplemental and 5 (10.7%) were odontoma in shape. The shortest distance between the supernumerary tooth and adjacent cortical plate varied between 0 to 2.5 mm with a mean of 0.66 mm. The most common clinical complaint was the non-eruption of permanent teeth (42.5%). All supernumerary teeth were removed under local anesthesia. Orthodontic traction was performed for those impacted permanent teeth if necessary. Impacted supernumerary teeth are usually in close proximity to cortical bone. Although this may facilitate surgical access, there is a risk of damaging surrounding anatomical structures. Therefore, CBCT

  20. Your Teeth

    MedlinePlus

    ... Aid & Safety Doctors & Hospitals Videos Recipes for Kids Kids site Sitio para niños How the Body Works Puberty & Growing Up Staying Healthy Staying Safe ... Answers Q&A Movies & More for Teens Teens site Sitio para adolescentes ... Your Teeth KidsHealth / For Kids / Your Teeth What's in this article? Tiny Teeth ...

  1. Primary failure of eruption: further characterization of a rare eruption disorder.

    PubMed

    Frazier-Bowers, Sylvia A; Koehler, Karen E; Ackerman, James L; Proffit, William R

    2007-05-01

    Posterior open bite has several possible causes, including primary failure of eruption (PFE) that affects all teeth distal to the most mesial involved tooth, mechanical failure of eruption (MFE) (primarily ankylosis) that affects only the involved tooth or teeth, and soft-tissue interferences with eruption (other). Radiographs and other clinical records for 97 cases of failure of posterior eruption submitted for consultation were analyzed to further characterize PFE and distinguish it from MFE. Of the 97 cases, 38 were judged to be clear-cut PFE; 19 were diagnosed as MFE; 32 were classified as indeterminate failure because they were too young to be certain of the distinction between PFE and MFE; and 8 were placed in the "other" category. Two subtypes of PFE were observed. In type 1, eruption failure occurred at or near the same time for all teeth in an affected quadrant. In type 2, a gradient of the time of failure was present, so that some further development of the teeth posterior to the most mesial affected tooth was observed before eruption failure. A family history of eruption problems was noted in 10 of the 38 PFE subjects (26%), and a pedigree analysis was done for 4 families. This was consistent with autosomal dominant transmission. The distinction between PFE and MFE is clinically important because it determines whether all posterior teeth, or only individual affected teeth, will not respond to orthodontic force. Certain diagnosis often requires progress radiographs so that the pattern of eruption of teeth distal to the most mesial affected tooth can be observed.

  2. Jupiter Eruptions

    NASA Image and Video Library

    2008-01-25

    NASA Hubble Space Telescope shows detailed analysis of two continent-sized storms that erupted in Jupiter atmosphere in March 2007 shows that Jupiter internal heat plays a significant role in generating atmospheric disturbances .

  3. Creeping eruption

    MedlinePlus

    ... eruption is more common in countries with warm climates. In the United States, the Southeast has the ... MD, PhD, Assistant Professor in Medicine, Harvard Medical School; Assistant in Medicine, Division of Infectious Disease, Department ...

  4. Tooth eruption sequence and dental crowding: a case-control study

    PubMed Central

    Moshkelgosha, Vahid; Khosravifard, Negar; Golkari, Ali

    2014-01-01

    When cases of dental crowding are identified and diagnosed promptly, interceptive orthodontics is particularly successful. Aim: To assess the differences in the eruption sequence of the mandibular canine and first premolar teeth in children with and without dental crowding. Materials and Methods: Children who attended the Shiraz Dental School's orthodontic clinic (Iran) from September to December 2012 were enrolled in this case-control study. Tooth size arch length discrepancy (TSALD) of all 8-10 year olds was calculated from patients’ dental models. Thirty-six children were randomly selected from those with TSALD of equal or less than 4mm (those with crowding). Each selected case was matched for sex and age with another child (as control) with TSALD>−4mm attending the same clinic, in the same time period. The existing panoramic radiographs were traced and the eruption percentages were measured for mandibular canine and first premolar teeth. The mean difference between canine and first premolar eruption percentages was compared between the case and control groups using the SPSS (version PASW 18) software and a paired sample t-test. Results: Canine and first premolar eruption percentages in the case group were 65.82±13.00 and 78.92±10.15 percent, respectively. The mean eruption percentages for canines and first premolars of the control group were 74.12±14.55 and 75.47±11.60 percent, respectively. There was a significant difference in pre-eruptive positions of canine and first premolar teeth in those with moderate to severe crowding when compared to the control group (p<0.001). Conclusion: These findings may improve the early diagnosis of children with high risk of developing moderate to severe crowding during mixed dentition. PMID:25110582

  5. Tooth Eruption Results from Bone Remodelling Driven by Bite Forces Sensed by Soft Tissue Dental Follicles: A Finite Element Analysis

    PubMed Central

    Sarrafpour, Babak; Swain, Michael; Li, Qing; Zoellner, Hans

    2013-01-01

    Intermittent tongue, lip and cheek forces influence precise tooth position, so we here examine the possibility that tissue remodelling driven by functional bite-force-induced jaw-strain accounts for tooth eruption. Notably, although a separate true ‘eruptive force’ is widely assumed, there is little direct evidence for such a force. We constructed a three dimensional finite element model from axial computerized tomography of an 8 year old child mandible containing 12 erupted and 8 unerupted teeth. Tissues modelled included: cortical bone, cancellous bone, soft tissue dental follicle, periodontal ligament, enamel, dentine, pulp and articular cartilage. Strain and hydrostatic stress during incisive and unilateral molar bite force were modelled, with force applied via medial and lateral pterygoid, temporalis, masseter and digastric muscles. Strain was maximal in the soft tissue follicle as opposed to surrounding bone, consistent with follicle as an effective mechanosensor. Initial numerical analysis of dental follicle soft tissue overlying crowns and beneath the roots of unerupted teeth was of volume and hydrostatic stress. To numerically evaluate biological significance of differing hydrostatic stress levels normalized for variable finite element volume, ‘biological response units’ in Nmm were defined and calculated by multiplication of hydrostatic stress and volume for each finite element. Graphical representations revealed similar overall responses for individual teeth regardless if incisive or right molar bite force was studied. There was general compression in the soft tissues over crowns of most unerupted teeth, and general tension in the soft tissues beneath roots. Not conforming to this pattern were the unerupted second molars, which do not erupt at this developmental stage. Data support a new hypothesis for tooth eruption, in which the follicular soft tissues detect bite-force-induced bone-strain, and direct bone remodelling at the inner surface of

  6. Impacted wisdom teeth.

    PubMed

    Dodson, Thomas B; Susarla, Srinivas M

    2010-04-08

    The incidence of impacted wisdom teeth is high, with some 72% of Swedish people aged 20 to 30 years having at least one impacted third molar. Impacted wisdom teeth occur because of a lack of space, obstruction, or abnormal position, and can cause inflammatory dental disease manifested by pain and swelling of infected teeth and may destroy adjacent teeth and bone. We conducted a systematic review and aimed to answer the following clinical questions: Should asymptomatic and disease-free impacted wisdom teeth be removed prophylactically? What are the effects of different surgical methods of removing impacted wisdom teeth? We searched: Medline, Embase, The Cochrane Library, and other important databases up to July 2009 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). We performed a GRADE evaluation of the quality of evidence for interventions. We found 25 systematic reviews, RCTs, or observational studies that met our inclusion criteria. In this systematic review we present information relating to the effectiveness and safety of the following interventions: prophylactic extraction, active surveillance, and different surgical methods of removing impacted wisdom teeth.

  7. Impacted wisdom teeth

    PubMed Central

    2014-01-01

    Introduction The incidence of impacted wisdom teeth (third molars) is high, with some 72% of Swedish people aged 20 to 30 years having at least one impacted wisdom tooth. Impacted wisdom teeth occur because of a lack of space, obstruction, or abnormal position. They can cause inflammatory dental disease manifested by pain and swelling of infected teeth and may destroy adjacent teeth and bone. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical questions: Should asymptomatic, disease-free impacted wisdom teeth be removed prophylactically? What are the effects of different operative (surgical) techniques for removing impacted wisdom teeth? We searched: Medline, Embase, The Cochrane Library, and other important databases up to October 2013 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). We performed a GRADE evaluation of the quality of evidence for interventions. Results We found 11 studies that met our inclusion criteria. Conclusions In this systematic review, we present information relating to the effectiveness and safety of the following interventions: prophylactic extraction, active surveillance, and different operative (surgical) techniques for extracting impacted wisdom teeth. PMID:25170946

  8. Impacted wisdom teeth.

    PubMed

    Dodson, Thomas B; Susarla, Srinivas M

    2014-08-29

    The incidence of impacted wisdom teeth (third molars) is high, with some 72% of Swedish people aged 20 to 30 years having at least one impacted wisdom tooth. Impacted wisdom teeth occur because of a lack of space, obstruction, or abnormal position. They can cause inflammatory dental disease manifested by pain and swelling of infected teeth and may destroy adjacent teeth and bone. We conducted a systematic review and aimed to answer the following clinical questions: Should asymptomatic, disease-free impacted wisdom teeth be removed prophylactically? What are the effects of different operative (surgical) techniques for removing impacted wisdom teeth? We searched: Medline, Embase, The Cochrane Library, and other important databases up to October 2013 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). We performed a GRADE evaluation of the quality of evidence for interventions. We found 11 studies that met our inclusion criteria. In this systematic review, we present information relating to the effectiveness and safety of the following interventions: prophylactic extraction, active surveillance, and different operative (surgical) techniques for extracting impacted wisdom teeth.

  9. Impacted wisdom teeth

    PubMed Central

    2010-01-01

    Introduction The incidence of impacted wisdom teeth is high, with some 72% of Swedish people aged 20 to 30 years having at least one impacted third molar. Impacted wisdom teeth occur because of a lack of space, obstruction, or abnormal position, and can cause inflammatory dental disease manifested by pain and swelling of infected teeth and may destroy adjacent teeth and bone. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical questions: Should asymptomatic and disease-free impacted wisdom teeth be removed prophylactically? What are the effects of different surgical methods of removing impacted wisdom teeth? We searched: Medline, Embase, The Cochrane Library, and other important databases up to July 2009 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). We performed a GRADE evaluation of the quality of evidence for interventions. Results We found 25 systematic reviews, RCTs, or observational studies that met our inclusion criteria. Conclusions In this systematic review we present information relating to the effectiveness and safety of the following interventions: prophylactic extraction, active surveillance, and different surgical methods of removing impacted wisdom teeth. PMID:21729337

  10. Eruptive Prominence

    NASA Image and Video Library

    2017-12-08

    Large, eruptive prominence in He II at 304Å, with an image of the Earth added for size comparison. This prominence from 24 July 1999 is particularly large and looping, extending over 35 Earths out from the Sun. Erupting prominences (when Earthward directed) can affect communications, navigation systems, even power grids, while also producing auroras visible in the night skies. Credit: NASA/GSFC/SOHO/ESA To learn more go to the SOHO website: sohowww.nascom.nasa.gov/home.html To learn more about NASA's Sun Earth Day go here: sunearthday.nasa.gov/2010/index.php

  11. [Wisdom teeth: which way to go?].

    PubMed

    Yitschaky, O; Segev-Neuhof, M; Laviv, A

    2016-01-01

    The debate regarding prophylactic extraction of mandibular third molar (Wisdom teeth) is not new. There is wide agreement among clinicians and researchers that an extraction in young age is easier and safer, but it may result in overtreatment, which means an unnecessary extraction of teeth that might have been functional and healthy. In order to avoid such overtreatment the clinician is obliged to be able to predict accurately the chances of third molar eruption, years before they are due to erupt. Additionally, the clinician has to estimate the chances for future pathology or infection that will force the patient to extract the tooth in years to come. In order to do so the clinician has to meticulously examine the teeth both clinically (including caries assessment of neighboring teeth, periodontal pocket depth measurements etc.) and radiographically. The purpose of this literature review is to present a balanced approach towards the issue of early prophylactic extraction of mandibular third molar.

  12. Knowledge of Teething and Prevalence of Teething Myths in Mothers of Saudi Arabia.

    PubMed

    Kumar, Santhosh; Tadakamadla, Jyothi; Idris, Ali; Busaily, Idris Ali A; AlIbrahim, Ahmed Yaqoub Ibrahim

    2016-01-01

    To assess the knowledge about teething, to evaluate the experiences of the mothers' during the teething of their youngest child and practices undertaken by them to relieve teething symptoms. A stratified cluster sampling technique was used to collect representative sample of school children of Jazan province (Saudi Arabia), who were provided with a questionnaire kit to be filled by their mothers. A total of 159 mothers participated in this study. More than four-fifths and three-fourths of the study population knew that the first primary teeth erupt at 6-7 months of age and lower central incisors are the first teeth to erupt respectively. The most prevalent signs and symptoms associated with teething as reported by the mothers were desire to bite (97.5%), fever (93%), diarrhoea (91.1%), increased salivation (79.9%), loss of appetite (77.4%) and gum irritation (71.7%). A little more than half (55.7%) of the mothers' gave their child a chilled object to bite and 42.1% bottle fed their baby at night to relieve teething pain. Many mothers had poor knowledge and misbeliefs about teething. There is a need to educate the mothers of Jazan province on the facts related to teething, specifically those related to teething pain relieving practices.

  13. Pattern and pace of dental eruption in Tarsius.

    PubMed

    Guthrie, Emily H; Frost, Stephen R

    2011-07-01

    This article uses data on the dental eruption pattern and life history of Tarsius to test the utility of Schultz's rule. Schultz's rule claims a relationship between the relative pattern of eruption and the absolute pace of dental development and life history and may be useful in reconstructing life histories in extinct primates. Here, we document an unusual eruption pattern in Tarsius combining early eruption (relative to molars) of anterior replacement teeth (P2 and incisors) and relatively late eruption of the posterior replacement teeth (C, P3, and P4). This eruption pattern does not accurately predict the "slow" pace of life documented for Tarsius [Roberts: Int J Primatol 15 (1994) 1-28], nor aspects of life history directly associated with dental development as would be expected using Schultz's rule. In Tarsius, the anterior teeth and M1 erupt at an early age and therefore are not only fast in a relative sense but also fast in an absolute sense. This seems to be related to a developmental anomaly in the deciduous precursor teeth, which are essentially skipped. This decoupling among dental eruption pattern, dental eruption pace, and life history pace in Tarsius undermines the assumptions that life histories can accurately be described as "fast" or "slow" and that dental eruption pattern alone can be used to infer overall life history pace. The relatively and absolutely early eruption of the anterior dentition may be due to the utility of these front teeth in early food acquisition rather than with the pace of life history. Copyright © 2011 Wiley-Liss, Inc.

  14. Popocatepetl Erupts

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The Popocatepetl Volcano, almost 30 miles south of Mexico City, erupted yesterday (December 18, 2000) in what authorities are calling its most spectacular eruption since 800 A.D. This morning, Popocatepetl (pronounced poh-poh-kah-TEH-peh-til) continued spewing red-hot rocks as well as a column of smoke and ash about 2.5 miles high into the atmosphere. This true-color image of the volcano was acquired today by the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) flying aboard the OrbView-2 satellite. In this image, Popocatepetl's plume (greyish pixels) can be seen blowing southward, away from Mexico City. There is a large cloud bank (bright white pixels) just to the east of the volcanic plume. Although Popocatepetl has been active since 1994-when it awoke from a 70-year slumber-this most recent eruption is most concerning to the greater Mexico City region's 20 million residents. The volcano demonstrated what it can do in 800 A.D. when it belched forth enough lava to fill many of the valleys in the surrounding region. Earlier, scientists warned the citizens of Mexico that there is a dome of lava at the base of the volcano that is causing pressure to build inside. They are concerned that, if it continues to build unabated, this pressure could cause even larger eruptions in the future. Image provided by the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

  15. CHANGES IN ANATOMIC POSITION OF ROOT CANAL ORIFICES IN PLURIRADICULAR TEETH FOLLOWING RE-LOCATION DURING ENDODONTIC TREATMENT.

    PubMed

    Rusu, Darian; Surlin, Petra; Stefan-Ioan, Stratul; Boariu, Marius; Horia, Calniceanu; Kasaj, Adrian; Sinescu, Cosmin; Andreea, Didilescu

    2018-02-16

    Direct access to the root canals in posterior teeth for endodontic treatment is most frequently facilitated by the straightening of the coronal parts of the root canals, having as a consequence the relocation of the canal orifices on the map of the floor of the pulp chamber (Christie & Thompson, 1994). This procedure intentionally moves the coronal aspect of a canal away from the center of the chamber, while simultaneously removing internal dentin from the pulp chamber walls. The aim of this study was to evaluate the displacement resulting from the relocation of root canal orifices during the initial phase of rotary root canal treatment in molars using the dental operating microscope (DOM) and digital image processing. Forty-three molars (17 maxillary and 26 mandibular) belonging to 43 patients (aged 18 to 62 years) with indications for root canal treatment were endodontically treated. The differences between the initial perimeter and the perimeter of the root canal orifices polygon after relocation varied between 2.7 and 3.4 microns (mean 3.0 microns), while the differences between the initial area and the area after relocation varied between 2,448,456.8 and 3,249,306.6 square microns (mean 2,848,881.7). The increase in access to the cavities and the alterations of the pulp chambers can be satisfactorily approximated by the variations of the perimeters and areas of the pulp floor polygons during root canal treatment. From a clinical perspective, these results indicate that there is a significant decrease in tooth substance in molars (except MB2). Copyright © 2018 Elsevier GmbH. All rights reserved.

  16. Multidisciplinary approach on rehabilitation of primary teeth traumatism repercussion on the permanent successor: 6-year follow-up case report.

    PubMed

    Mello-Moura, A C V; Bonini, G A V C; Suga, S S; Navarro, R S; Wanderley, M T

    2009-01-01

    Traumatic lesions in primary teeth are frequent in pediatric patients and can cause problems both to the deciduous tooth and permanent successor. The impact strength on deciduous tooth can reach the growing permanent tooth, affecting its morphology, structure and position, or even hampering its proper development. This report describes an aesthetic-functional rehabilitation process in an 8 year 10 month old boy during a multidisciplinary treatment held at the Clinical Center of Dental Trauma in Primary Teeth of the Pediatric Dentistry of Dental College of University of São Paulo, Brazil. The patient presented bilateral posterior cross bite and the permanent left upper central incisor with ectopic eruption and enamel hypoplasy, preceded by avulsion of element 61, occurred when the patient was 1.6 years old. After diagnosis and treatment planning, a quick expansion of jaws was recommended with Hass-type rapid expander and orthodontic leveling with fixed braces. Due to the ectopic eruption, the gingival contour had been altered and hypertrophia was found, compromising aesthetics and avoiding local hygienic procedures. Gingivoplasty was carried out with high-intensity Diode Laser, followed by aesthetic restoration with compound resin. It was concluded that after deciduous teeth traumatism it is important that the patient undergoes clinic and radiographic assistance until the permanent teeth erupt so that an adequate multidisciplinary treatment can be offered to the patient.

  17. The Innervation of Teeth

    PubMed Central

    Bradlaw, Robert

    1936-01-01

    The author, using the staining methods of Bielschowski, Gross, Beckwith, Weigert-Pal and Cajal in frozen and serial paraffin and celloidin sections, has investigated the dental innervations of man, monkey, dog, cat, and guinea-pig in health and disease. He discusses the anatomy and physiology of the dental innervation and the effect of section of the inferior dental nerve on the trophic, vasomotor, protective, and sensory functions, with special reference to the relation between dental disease and neuropathies. He describes the innervation of the tooth germ and the nature of the growing fibrils seen before calcification in the dentinal papilla and draws attention to the innervation of the periodontal membrane. He has found that these nerves anastomose across the crest of the interdental septa with their fellows and demonstrates coiled sub-cemental nerve-endings. He has been unable to find any difference in the eruption and casting of teeth after section of the inferior dental nerve, and does not find degeneration of the nerves of deciduous teeth prior to casting to be inevitable. He discusses the effect of local anæsthesia on the dental pulp, some of the causes of odontalgia and neuralgia and the effect of old age and general disease on the dental innervation. He has failed with lethal or continued sublethal doses of ethyl and methyl alcohol, lead or tetanus and diphtheria toxins, using the oral, gastric, subcutaneous and intravenous route, to produce dental neuronic change. The effects of fracture of teeth and jaws, the introduction of arsenic into the pulp chamber and amputation and extirpation of the pulp are examined. The vital resistance of the pulp and the significance of granulomata as a protective mechanism are discussed. The author has found that after extraction although there is at first degeneration of the nerve-fibres concerned, there may subsequently be regeneration, sometimes in the form of plexiform neuroma. He has produced degenerative changes in

  18. Development of coronal cementum in hypsodont horse cheek teeth.

    PubMed

    Sahara, Noriyuki

    2014-04-01

    The horse is a grazing herbivore whose cheek teeth are hypsodon; that is, they possess long crowns that are completely covered by coronal cement at eruption. For elucidation of the sequential events in the formation of this coronal cementum in the mandibular horse cheek teeth, in the present study the lower 3rd permanent premolar teeth (PM4 ) from 3.5-, 4-, and 5-year-old horses were compared by using radiography, microcomputed tomography (Miro-CT), light microscopy (LM), and scanning electron microscopy (SEM). The present study clearly showed that prior to coronal cementogenesis tartrate-resistant acid phosphatase (TRAP)-positive odontoclasts resorbed on the enamel surface of the reserve crown in horse cheek tooth. Enamel resorption areas were relatively narrow, and started from the cuspal tips, and moved in the apical direction during tooth development. A primary cementum was initially deposited on the irregularly pitted enamel-cementum junction (ECJ) of the infolding and peripheral enamel. The infolding cementum filled grooves completely by the time of tooth eruption. On the other hand, in the peripheral cementum, the secondary and tertiary cementum layers were sequentially deposited on the primary cementum. These two cementum layers were sites for the insertion of the periodontal ligaments, and were continually laid down on the primary cementum coronally rather than apically throughout the life. The results of the present study suggest that the coronal cementum of horse cheek teeth is a multistructural and multifunctional tissue, meeting the requirements of its many different functions. Copyright © 2014 Wiley Periodicals, Inc.

  19. [Primary failure of eruption (PFE). Clinical and molecular genetics analysis].

    PubMed

    Stellzig-Eisenhauer, Angelika; Decker, Eva; Meyer-Marcotty, Philipp; Rau, Christiane; Fiebig, Britta S; Kress, Wolfram; Saar, Kathrin; Rüschendorf, Franz; Hubner, Norbert; Grimm, Tiemo; Witt, Emil; Weber, Bernhard H F

    2013-09-01

    The term "primary failure of eruption" (PFE) refers to the complete or partial failure of a primary non-ankylosed tooth to erupt due to a disturbance of the eruption mechanism. Up to now, the molecular basis for this failure was unknown. Four families were studied in whom at least two members were affected by non-syndromic PFE as part of a clinical and molecular genetics study. Radiological diagnostics (OPTs) were carried out in all patients and their unaffected relatives (control group). The genetic analysis included a genomewide linkage analysis followed by direct DNA sequencing of positional candidate genes. Starting from the index patients, we were able to reconstruct pedigrees over two and/or three generations in the families that indicated an autosomal-dominant mode of inheritance of non-syndromic PFE. Fifteen patients were diagnosed with PFE. Gender distribution was nearly equal (7 female, 8 male). Molecular genetic analysis of the PTHR1 gene revealed three distinct heterozygous mutations (c.1050-3C>G; c.543 + 1G>A; c.463G>T). Unaffected persons exhibited no mutations. Knowledge of the genetic causes of non-syndromic PFE can now be used for the differential diagnosis of eruption failure. It permits affected family members to be identified early and may lead to new treatment possibilities in the long term. The genetically-verified diagnosis of "primary failure of eruption" can protect patients and orthodontists from years of futile treatment, because orthodontic treatment alone does not lead to success. Moreover, it has a negative influence on unaffected teeth and areas of the jaw. © EDP Sciences, SFODF, 2013.

  20. Intra-pulp temperature increase of equine cheek teeth during treatment with motorized grinding systems: influence of grinding head position and rotational speed

    PubMed Central

    2014-01-01

    Background In equine practice, teeth corrections by means of motorized grinding systems are standard procedure. The heat resulting from that treatment may cause irreparable damage to the dental pulp. It has been shown that a 5.5°C temperature rise may cause severe destruction in pulp cells. Hence, the capability to continuously form secondary dentine is lost, and may lead, due to equine-typical occlusal tooth abrasion, to an opening of the pulp cavity. To obtain reliable data on the intra-pulp increase in temperature during corrective treatments, equine cheek teeth (CT) were modified in a way (occlusal surface smoothed, apical parts detached, pulp horns standardized) that had been qualified in own former published studies. All parameters influencing the grinding process were standardized (force applied, initial temperatures, dimensions of pulp horns, positioning of grinding disk, rotational speed). During grinding experiments, imitating real dental treatments, the time span for an intra-pulp temperature increase of 5.5°C was determined. Results The minimum time recorded for an intra-pulp temperature increase of 5.5°C was 38 s in mandibular CT (buccal grinding, 12,000 rpm) and 70 s in maxillary CT (flat occlusal grinding, 12,000 rpm). The data obtained showed that doubling the rotational speed of the disk results in halving the time span after which the critical intra-pulp temperature increase in maxillary CT is reached. For mandibular CT, the time span even drops by two thirds. Conclusion The use of standardized hypsodont CT enabled comparative studies of intra-pulp heating during the grinding of occlusal tooth surfaces using different tools and techniques. The anatomical structure of the natural vital hypsodont tooth must be kept in mind, so that the findings of this study do not create a deceptive sense of security with regard to the time-dependent heating of the native pulp. PMID:24559121

  1. A newer approach in positioning teeth for dental prosthetics using lateral cephalometric, trans-cranial radiographs, and the Denar-Witzig articulator: a case of hypodontia in an adolescent patient.

    PubMed

    Chapra, A; White, G E

    2001-01-01

    Traditionally in full denture prosthetics, anterior teeth are set on the models, independent of the effects on the face. More enlightened dentists, will then adjust the wax-up for speech, and some effects on the lips. Consideration is infrequently given to restoring the face by repositioning the teeth and mandible. Rarely is thought given to the effects of occlusion on the posture of the body. This report uses several techniques to restore facial esthetics and body posture. The techniques used include a cephalometric radiograph, transcranial radiographs, an articulator that has an adjustable "TMJ" (Denar-Witzig), and Symmetrigraf Posture Chart. This clinical report describes a newer approach in the positioning of maxillary anterior teeth for a patient with hypodontia and nail dysplasia syndrome, and the overall effect of this approach on the face and posture of the patient. Conventionally the precise form of the maxillary wax rim is fabricated with considerable variation from technician to another, based on the technicians training. This variation is evident on the position of the labial aspect of the rim horizontally and vertically. The wax rim is then further adjusted chair side based on subjective evaluation of the face. The maxillary anterior teeth position is established without considering that the lip position is not yet accustomed to the wax rim.

  2. Supernumerary teeth "mesiodens". Case report.

    PubMed

    Itro, A; Difalco, P

    2003-09-01

    The supernumerary tooth is an anomaly of dental eruption that is not rare to find in the clinical practice. Among the supernumerary teeth the "mesiodens" is most frequent. The mesiodens is found in the region of the superior central incisors and it can be the cause of many complications. The aim of this work is the description of a rare symptomatic case of mesiodens and the diagnostic and therapeutic strategies to adopt when this dental anomaly occurs. In particular the authors suggest making radiographic examinations only in the family of patients with dental anomalies of number, thinking that the incidence of such anomalies is too low to justify mass radiographic examinations.

  3. Three-dimensional analysis of mandibular growth and tooth eruption.

    PubMed

    Krarup, S; Darvann, T A; Larsen, P; Marsh, J L; Kreiborg, S

    2005-11-01

    Normal and abnormal jaw growth and tooth eruption are topics of great importance for several dental and medical disciplines. Thus far, clinical studies on these topics have used two-dimensional (2D) radiographic techniques. The purpose of the present study was to analyse normal mandibular growth and tooth eruption in three dimensions based on computer tomography (CT) scans, extending the principles of mandibular growth analysis proposed by Björk in 1969 from two to three dimensions. As longitudinal CT data from normal children are not available (for ethical reasons), CT data from children with Apert syndrome were employed, because it has been shown that the mandible in Apert syndrome is unaffected by the malformation, and these children often have several craniofacial CT scans performed during childhood for planning of cranial and midface surgery and for follow-up after surgery. A total of 49 datasets from ten children with Apert syndrome were available for study. The number of datasets from each individual ranged from three to seven. The first CT scan in each of the ten series was carried out before 1 year of age, and the ages for the 49 scans ranged from 1 week to 14.5 years. The mandible and the teeth were segmented and iso-surfaces generated. Landmarks were placed on the surface of the mandible, along the mandibular canals, the inner contour of the cortical plate at the lower border of the symphysis menti, and on the teeth. Superimposition of the mandibles in the longitudinal series was performed using the symphysis menti and the mandibular canals as suggested by Björk. The study supported the findings of stability of the symphysis menti and the mandibular canals as seen in profile view previously reported by Björk & Skieller in 1983. However, the mandibular canals were, actually, relocated laterally during growth. Furthermore, the position of tooth buds remained relatively stable inside the jaw until root formation started. Eruption paths of canines and

  4. Three-dimensional analysis of mandibular growth and tooth eruption

    PubMed Central

    Krarup, S; Darvann, TA; Larsen, P; Marsh, JL; Kreiborg, S

    2005-01-01

    Normal and abnormal jaw growth and tooth eruption are topics of great importance for several dental and medical disciplines. Thus far, clinical studies on these topics have used two-dimensional (2D) radiographic techniques. The purpose of the present study was to analyse normal mandibular growth and tooth eruption in three dimensions based on computer tomography (CT) scans, extending the principles of mandibular growth analysis proposed by Björk in 1969 from two to three dimensions. As longitudinal CT data from normal children are not available (for ethical reasons), CT data from children with Apert syndrome were employed, because it has been shown that the mandible in Apert syndrome is unaffected by the malformation, and these children often have several craniofacial CT scans performed during childhood for planning of cranial and midface surgery and for follow-up after surgery. A total of 49 datasets from ten children with Apert syndrome were available for study. The number of datasets from each individual ranged from three to seven. The first CT scan in each of the ten series was carried out before 1 year of age, and the ages for the 49 scans ranged from 1 week to 14.5 years. The mandible and the teeth were segmented and iso-surfaces generated. Landmarks were placed on the surface of the mandible, along the mandibular canals, the inner contour of the cortical plate at the lower border of the symphysis menti, and on the teeth. Superimposition of the mandibles in the longitudinal series was performed using the symphysis menti and the mandibular canals as suggested by Björk. The study supported the findings of stability of the symphysis menti and the mandibular canals as seen in profile view previously reported by Björk & Skieller in 1983. However, the mandibular canals were, actually, relocated laterally during growth. Furthermore, the position of tooth buds remained relatively stable inside the jaw until root formation started. Eruption paths of canines and

  5. Jupiter Eruptions

    NASA Technical Reports Server (NTRS)

    2008-01-01

    [figure removed for brevity, see original site] Click on the image for high resolution image of Nature Cover

    Detailed analysis of two continent-sized storms that erupted in Jupiter's atmosphere in March 2007 shows that Jupiter's internal heat plays a significant role in generating atmospheric disturbances. Understanding these outbreaks could be the key to unlock the mysteries buried in the deep Jovian atmosphere, say astronomers.

    This visible-light image is from NASA's Hubble Space Telescope taken on May 11, 2007. It shows the turbulent pattern generated by the two plumes on the upper left part of Jupiter.

    Understanding these phenomena is important for Earth's meteorology where storms are present everywhere and jet streams dominate the atmospheric circulation. Jupiter is a natural laboratory where atmospheric scientists study the nature and interplay of the intense jets and severe atmospheric phenomena.

    According to the analysis, the bright plumes were storm systems triggered in Jupiter's deep water clouds that moved upward in the atmosphere vi gorously and injected a fresh mixture of ammonia ice and water about 20 miles (30 kilometers) above the visible clouds. The storms moved in the peak of a jet stream in Jupiter's atmosphere at 375 miles per hour (600 kilometers per hour). Models of the disturbance indicate that the jet stream extends deep in the buried atmosphere of Jupiter, more than 60 miles (approximately100 kilometers) below the cloud tops where most sunlight is absorbed.

  6. Observation of Children's Teeth as a Diagnostic Aid: A Review

    PubMed Central

    Gibson, W. M.; Conchie, John M.

    1964-01-01

    The accuracy of information obtained from such a simple procedure as looking in the mouth as a measure of child development led to this review. The relationship between dental and physical development has been known for many years. Methods of assessing maturity by counting erupted teeth are described. Measurements taken on two boys illustrated this hypothesis, and from these the close correlation between height and weight, bone age and dental age is shown. It is suggested that physicians and dentists should record the number of erupted teeth on interval examinations, since the pattern of eruption and calcification of teeth may present the first indication of developmental retardation. ImagesFig. 1a PMID:14104154

  7. Teeth Injuries (For Parents)

    MedlinePlus

    ... Videos for Educators Search English Español First Aid: Teeth Injuries KidsHealth / For Parents / First Aid: Teeth Injuries ... or young child injures the gums or baby teeth: Apply pressure to the area (if it's bleeding) ...

  8. Does fluoride in drinking water delay tooth eruption?

    PubMed

    Jolaoso, Ismail Adeyemi; Kumar, Jayanth; Moss, Mark E

    2014-01-01

    The objectives of this study are to determine the effect of fluoride exposure on permanent tooth eruption patterns as well as to understand its effect on caries attack rate by accounting for the number of erupted tooth surfaces. We analyzed data from the 1986-1987 National Survey of Oral Health of US Schoolchildren to determine the mean number of erupted permanent teeth and permanent first molars according to fluoride level in drinking water. The analysis included 13,348 children aged 5-17 years with a history of single residence. We also estimated the attack rate (decayed, missing, and filled surfaces/surfaces at risk) for fluoride deficient, suboptimal, and optimally fluoridated areas adjusting for covariates. Multivariable statistical analyses were performed to control for potential confounders. By age 7, almost all permanent first molars had erupted. The adjusted mean number of erupted permanent first molars per child were 3.81, 3.67, and 3.92 in areas with <0.3, 0.3-<0.7, and 0.7-1.2 ppm of fluoride, respectively. The adjusted caries attack rate in the first permanent molars among 5- to 17-year-old children was 93, 81, and 78 per 1,000 surfaces in fluoride deficient, suboptimal, and optimally fluoridated areas, respectively (P < 0.0001). This pattern of higher first molar attack rate among children in the fluoride-deficient communities was also observed in all erupted teeth. Exposure to fluoride in drinking water did not delay the eruption of permanent teeth. The observed difference in dental caries experience among children exposed to different fluoride levels could not be explained by the timing of eruption of permanent teeth. © 2014 American Association of Public Health Dentistry.

  9. Volcanic Eruptions and Climate: Outstanding Research Issues

    NASA Astrophysics Data System (ADS)

    Robock, Alan

    2016-04-01

    Large volcanic eruptions inject sulfur gases into the stratosphere, which convert to sulfate aerosols with an e-folding residence time of about one year. The radiative and chemical effects of this aerosol cloud produce responses in the climate system. Based on observations after major eruptions of the past and experiments with numerical models of the climate system, we understand much about their climatic impact, but there are also a number of unanswered questions. Volcanic eruptions produce global cooling, and are an important natural cause of interannual, interdecadal, and even centennial-scale climate change. One of the most interesting volcanic effects is the "winter warming" of Northern Hemisphere continents following major tropical eruptions. During the winter in the Northern Hemisphere following every large tropical eruption of the past century, surface air temperatures over North America, Europe, and East Asia were warmer than normal, while they were colder over Greenland and the Middle East. This pattern and the coincident atmospheric circulation correspond to the positive phase of the Arctic Oscillation. While this response is observed after recent major eruptions, most state-of-the-art climate models have trouble simulating winter warming. Why? High latitude eruptions in the Northern Hemisphere, while also producing global cooling, do not have the same impact on atmospheric dynamics. Both tropical and high latitude eruptions can weaken the Indian and African summer monsoon, and the effects can be seen in past records of flow in the Nile and Niger Rivers. Since the Mt. Pinatubo eruption in the Philippines in 1991, there have been no large eruptions that affected climate, but the cumulative effects of small eruptions over the past decade have had a small effect on global temperature trends. Some important outstanding research questions include: How much seasonal, annual, and decadal predictability is possible following a large volcanic eruption? Do

  10. The primary and mixed dentition, post-eruptive enamel maturation and dental caries: a review.

    PubMed

    Lynch, Richard J M

    2013-12-01

    The mouth is in flux from the time the primary teeth begin to erupt, in the first year of life, through to the end of the 'mixed dentition' (i.e. the concurrent eruption of the permanent teeth and exfoliation of the primary teeth), at around 12 years of age. Primary teeth facilitate the development of the facial muscles and speech. They act as 'guides' for erupting permanent teeth. If lost prematurely, subsequent misalignment of permanent teeth can make them difficult to clean and possibly more caries-prone. During the mixed dentition phase, teeth are at relatively high risk of caries. Erupting teeth are difficult to clean and cleaning may be avoided because of tender gums and behavioural factors in children. Permanent enamel (and possibly primary enamel) undergoes post-eruptive maturation, accumulating fluoride, becoming harder, less porous and less caries-prone. Overall, primary teeth are more vulnerable to caries than permanent teeth. Widespread use of fluoride toothpaste has effected marked reductions in caries. Some evidence exists that fluoride delivered from toothpastes may be somewhat more effective in reducing caries in primary than in permanent teeth. However, caries remains a public health concern globally. New fluoride toothpaste formulations, optimised using in vivo fluoride delivery and efficacy studies, may improve the caries resistance of mineral deposited during post-eruptive maturation. Behaviour should not be ignored; new formulations will be more effective if used according to professionally endorsed recommendations based on sound science. Establishing good oral hygiene behaviour early in life can lead to lasting anti-caries benefits. © 2013 FDI World Dental Federation.

  11. Effects of mesiodens on adjacent permanent teeth: a retrospective study in Korean children based on cone-beam computed tomography.

    PubMed

    Kim, Yuhyun; Jeong, Taesung; Kim, Jiyeon; Shin, Jonghyun; Kim, Shin

    2018-03-01

    Mesiodens can be associated with several complications. The optimal age for treatment, however, remains controversial. To investigate the three-dimensional (3D) positions of mesiodens using cone-beam computed tomography (CBCT) and determine the association of eruption-related complications of mesiodens with these 3D positions and delayed development of the central incisors. In total, 293 Korean children (383 supernumerary teeth) aged 4-10 years with no history of orthodontic treatment were included. CBCT and panoramic radiography data for all patients were retrospectively investigated with regard to the 3D positions of mesiodens, apical maturity of the permanent first molars, delayed development of the central incisors relative to the apical maturity of the permanent first molars (Nolla's stage), and eruption-related complications of mesiodens. Eruption-related complications were not correlated with any 3D characteristic other than the 'within the arch' position of mesiodens, while they showed a significant correlation with delayed development of the central incisors (P < 0.05). Mesiodens caused eruption-related complications in 33.7% patients. Moreover, the risk of these complications was higher when mesiodens caused delayed development of the central incisors. These findings can aid clinicians in planning appropriate and timely treatment for mesiodens, with focus on minimising patient discomfort. © 2017 BSPD, IAPD and John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  12. Dapsone-associated fixed drug eruption.

    PubMed

    Garcia, Daniel; Cohen, Philip R

    2017-07-01

    Dapsone is a sulfone drug used to treat infectious conditions and also numerous dermatologic diseases. Fixed drug eruption is a distinctive adverse cutaneous reaction associated with the initial administration and subsequent delivery of a specific agent. Areas covered: The authors preformed a literature search using the following keywords: dapsone, fixed drug eruption, and adverse cutaneous drug reaction. Bibliographies were also reviewed for pertinent articles. The results were combed for relevant papers and reviewed. Articles pertaining to dapsone-associated fixed drug eruption were included. Expert commentary: The majority of cases of dapsone-associated fixed drug eruption in the literature come from Africa or India where there is a high prevalence of patients treated for leprosy. Characteristics of these cases are similar to fixed drug eruption described in the western literature, with differences in frequency of multiple versus solitary lesions. Dapsone-associated fixed drug eruption should be considered when reviewing the drug history of a patient with fixed drug eruption. In the case of darker pigmented individuals, multiple fixed drug eruption lesions may be more common. Multiple lesions may mimic Kaposi's sarcoma in human immunodeficiency virus positive patients. Dapsone-associated fixed drug eruption should be considered in the differential diagnosis of multiple hyperpigmented lesions.

  13. Mechanisms of Tooth Eruption and Orthodontic Tooth Movement

    PubMed Central

    Wise, G.E.; King, G.J.

    2008-01-01

    Teeth move through alveolar bone, whether through the normal process of tooth eruption or by strains generated by orthodontic appliances. Both eruption and orthodontics accomplish this feat through similar fundamental biological processes, osteoclastogenesis and osteogenesis, but there are differences that make their mechanisms unique. A better appreciation of the molecular and cellular events that regulate osteoclastogenesis and osteogenesis in eruption and orthodontics is not only central to our understanding of how these processes occur, but also is needed for ultimate development of the means to control them. Possible future studies in these areas are also discussed, with particular emphasis on translation of fundamental knowledge to improve dental treatments. PMID:18434571

  14. Wisdom tooth eruption secondary to localized lower molar mesialization in patients with aplastic lower second premolars.

    PubMed

    Zimmer, Bernd

    2006-01-01

    After localized space closure in the mandible it is desirable to preserve lower wisdom teeth as natural replacements for missing second premolars and as antagonists for upper second molars. The aim of this study was to determine whether this treatment method can obviate the need for prosthodontic restorations, implants, and third molar osteotomy. Furthermore the time point of possible third molar eruption was to be determined and whether further orthodontic interventions were required to achieve their alignment. The test group comprised 34 patients who exhibited agenesis of one or both lower second premolars (n = 45) in conjunction with a corresponding number of third molar tooth germs. Follow-up examinations were performed 2 to 8 years after conclusion of orthodontic treatment involving push-and-pull mechanics (PPM) without extraction of any contralateral teeth. The results of the clinical retrospective follow-up examination at consecutive post-treatment endpoints were compared with two orthodontic control groups (A: 4-premolar extraction group, B: non-extraction group). After an average of 4 years and 2 months, the percentage of fully-erupted third molars in the agenesis group with localized space closure was 82%, compared to 29% and 28%, respectively, in the controls. These differences were statistically significant (p < or = 0.01). The success rate in the agenesis group reached 94% when the 4- to 8-year results were considered in isolation. Compared with the contralateral (non-aplastic) side, teeth on the aplastic side erupted prematurely. In 9% of the cases, minor orthodontic interventions were required to exactly position the third molars. There is high probability that mandibular third molars can be preserved after localized space closure, obviating the need for prosthodontic restorations, dental implants, and third molar osteotomies.

  15. Extraction of primary (baby) teeth for unerupted palatally displaced permanent canine teeth in children.

    PubMed

    Parkin, Nicola; Furness, Susan; Shah, Anwar; Thind, Bikram; Marshman, Zoe; Glenroy, Gillian; Dyer, Fiona; Benson, Philip E

    2012-12-12

    The permanent canine tooth in the maxillary (upper) jaw sometimes does not erupt into the mouth correctly. In about 1% to 3% of the population these teeth will be diverted into the roof of the mouth (palatally). It has been suggested that if the primary canine is removed at the right time this palatal eruption might be avoided. This is an update of a Cochrane review first published in 2009. To evaluate the effect of extracting the primary maxillary canine on the eruption of the palatally ectopic maxillary permanent canine. We searched the following electronic databases: the Cochrane Oral Health Group's Trials Register (to 20 April 2012), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2012, Issue 1), MEDLINE via OVID (1946 to 20 April 2012) and EMBASE via OVID (1980 to 20 April 2012). There were no restrictions regarding language or date of publication. Trials were selected if they met the following criteria: a randomised or quasi-randomised controlled trial, involving the extraction of the deciduous maxillary canine and assessing eruption/non-eruption of the palatally displaced maxillary permanent canine. Data extraction was undertaken independently by two review authors. The primary outcome was the reported prevalence of eruption or non-eruption of the ectopic permanent canine into the mouth following observation or intervention. Results were to be expressed as risk ratios for dichotomous outcomes with 95% confidence intervals and mean differences for continuous outcomes. Heterogeneity was to be investigated, including both clinical and methodological factors. Authors of trials were contacted to request unpublished data. Reports of two randomised controlled trials previously excluded from an earlier version of the review due to "deficiencies in reporting, insufficient data" have now been included. These two trials included approximately 128 children, with more than 150 palatally displaced canine teeth, and both were conducted by

  16. The association between childhood obesity and tooth eruption.

    PubMed

    Must, Aviva; Phillips, Sarah M; Tybor, David J; Lividini, Keith; Hayes, Catherine

    2012-10-01

    Obesity is a growth-promoting process as evidenced by its effect on the timing of puberty. Although studies are limited, obesity has been shown to affect the timing of tooth eruption. Both the timing and sequence of tooth eruption are important to overall oral health. The purpose of this study was to examine the association between obesity and tooth eruption. Data were combined from three consecutive cycles (2001-2006) of the National Health and Nutrition Examination Survey (NHANES) and analyzed to examine associations between the number of teeth erupted (NET) and obesity status (BMI z-score >95th percentile BMI relative to the Centers for Disease Control and Prevention (CDC) growth reference) among children 5 up to 14 years of age, controlling for potential confounding by age, gender, race, and socioeconomic status (SES). Obesity is significantly associated with having a higher average NET during the mixed dentition period. On average, teeth of obese children erupted earlier than nonobese children with obese children having on average 1.44 more teeth erupted than nonobese children, after adjusting for age, gender, and race/ethnicity (P < 0.0001). SES was not a confounder of the observed associations. Obese children, on average, have significantly more teeth erupted than nonobese children after adjusting for gender, age, and race. These findings may have clinical importance in the area of dental and orthodontic medicine both in terms of risk for dental caries due to extended length of time exposed in the oral cavity and sequencing which may increase the likelihood of malocclusions.

  17. Forced eruption with miniscrews; inter-arch [corrected] method with vertical elastics versus intra-arch method using the Derton-Perini technique: two case reports.

    PubMed

    Derton, Nicola; Derton, Roberto; Perini, Alessandro

    2011-06-01

    Orthodontic preprosthetic treatment is an important feature of interdisciplinary dental therapy in the adult patient. Extrusion can be very useful to obtain successful prosthodontic results. The literature describes different ways to obtain forced dental eruption. Miniscrews represent a step towards resolving the problem of anchorage in orthodontics, including in forced eruption cases. The aim of this study is to report two cases of orthodontic preprosthetic extrusion by means of miniscrews and bone anchorage. We will describe and discuss the indications, orthodontic and surgical technique and the clinical advantages. In the first reported case, a decayed upper molar was extruded using miniscrews and an inter-arch technique (direct skeletal anchorage), which needs patient compliance to properly position the inter-arch elastics. In the second case, an upper premolar with an oblique corono-radicular fracture underwent forced eruption by means of intra-arch miniscrews (indirect bone anchorage with the "Derton-Perini" technique). Patient compliance was not required. Adequate extrusion of the treated teeth was obtained, with no undesired movement of the neighbouring teeth. Using the "Derton-Perini" technique, we reached our objectives without patient compliance. Miniscrews for skeletal anchorage proved to be an effective device to obtain extrusion for prosthetic purposes without undesired movements on other teeth and with no need for patient compliance when used in the same arch. Copyright © 2011. Published by Elsevier Masson SAS.

  18. Outcome of Endodontically Treated Cracked Teeth

    DTIC Science & Technology

    2016-06-01

    reported retrospective results from 49 patients who received root canal treatment for cracked teeth. The data included the presence of periodontal pocketing... periodontal pocketing, patients’ age and gender, location of cracked teeth, type of teeth and presence of terminal cracked tooth. The 2-year survival rate was...85.5%. Factors that decreased outcomes were the terminal tooth position in the arch, the presence of periodontal pocketing prior to endodontic

  19. Signs and symptoms associated with primary tooth eruption: a clinical trial of nonpharmacological remedies.

    PubMed

    Memarpour, Mahtab; Soltanimehr, Elham; Eskandarian, Taherh

    2015-07-28

    To evaluate disturbances in primary tooth eruption and their management with nonpharmacological remedies. In this nonrandomized clinical trial, 270 children aged between 8 and 36 months were selected and divided into 5 groups with 54 children initially enrolled in each group. The children were seen during an 8-day period during tooth eruption. At each appointment data were recorded from oral examination, tympanic temperature measurement and a questionnaire. The five methods used as remedies to reduce teething symptoms were: 1) cuddle therapy, 2) ice, 3) rubbing the gums, 4) teething rings and 5) food for chewing. Teething symptoms, the type of erupted tooth, symptoms of recovery and the mother's satisfaction with treatment were evaluated. Two hundred and fifty four children (mean age 16 ± 7.2 months) completed the study. The most frequent teething symptoms were drooling (92%), sleep disturbances (82.3%) and irritability (75.6%). These symptoms were more pronounced in low birth weight children (p > 0.05). Canine eruption led to more loss of appetite than incisor (p = 0.033) or molars eruption (p = 0.014). Low grade increases in body temperature were observed only on the day of eruption (36.70 ± 0.39 °C), when body temperature was significantly different compared to the day before and the day after eruption (both p < 0.001). There was no significant correlation between fever as reported by mothers and temperature readings obtained by the investigators. The most favorable results for time to recovery and the mother's satisfaction were seen when teething rings were used, followed by cuddle therapy and rubbing the gums. There was no association between teething and symptoms such as fever or diarrhea. Low birth weight children may have more teething symptoms. Teething rings, cuddle therapy and rubbing the gums were the most effective methods to reduce symptoms. Iranian Registry of Clinical Trials: code IRCT201211127402N3.

  20. Herculaneum: Clues to Vesuvius eruption

    NASA Astrophysics Data System (ADS)

    Richman, Barbara T.

    More than 80 skeletons have been unearthed in the ancient Mediterranean town of Herculaneum, west of Italy's Mount Vesuvius. This anthropological find corroborates a reinterpretation by three University of Rhode Island scientists of the sequence of the August A.D. 79 eruption of Vesuvius. In addition, the discovery is the first proof that large numbers of people perished as they tried to flee from the eruption, estimated to have been about 10 times more powerful than the May 1980 Mount St. Helens blast.‘Who says dead men don't talk? Their bones have something to say about them and their everyday lives,’ says Sara C. Bisel, a physical anthropologist who analyzed the skeletons. Among the remains are a cluster of skeletons from six adults, four children, and two infants trying to shield themselves from the volcanic onslaught; the skeleton of a sailor, still clutching an oar, lying on his back beside an 8-m-long capsized boat; a woman whose now bony hand was still graced with gem-encrusted gold rings; and a soldier (see Figure 1). From these and other finds the anthropological team was able to discern that the ancient Romans, on average, were shorter than modern citizens and, judging from the condition of some of the teeth, probably had a low-sugar diet.

  1. Varanoid Tooth Eruption and Implantation Modes in a Late Cretaceous Mosasaur.

    PubMed

    Liu, Min; Reed, David A; Cecchini, Giancarlo M; Lu, Xuanyu; Ganjawalla, Karan; Gonzales, Carol S; Monahan, Richard; Luan, Xianghong; Diekwisch, Thomas G H

    2016-01-01

    Erupting teeth are some of the oldest witnesses of developmental processes in the vertebrate fossil record and provide an important resource for vertebrate cladistics. Here, we have examined a mosasaur jaw fragment from central Texas using ultrathin ground section histology and 3D tomographic imaging to assess features critical for the cladistic placement of mosasaurs among varanoids vs. snakes: (i) the orientation of replacement teeth compared to the major tooth axis, (ii) the occurrence of resorption pits, and (iii) the mode of tooth implantation/attachment to the tooth bearing element (TBE). The replacement tooth studied here developed in an inclined position slightly distal of the deciduous parent tooth, similar to another varanoid squamate, the Gila monster Heloderma suspectum. Ground sections and tomographs also demonstrated that the replacement tooth attachment apparatus was entirely intact and that there was no evidence of mechanical deformation. Sections and tomographs further illustrated that the replacement tooth was located within a bony crypt and the inclination of the crypt matched the inclination of the replacement tooth. These preparations also revealed the presence of a resorption pit within the boundaries of the deciduous tooth that surrounded the developing replacement tooth. This finding suggests that developing mosasaur teeth developed within the walls of resorption pits similar to varanoid tooth germs and unlike developing snake teeth which are surrounded by fibrous connective tissue integuments. Finally, mosasaurs featured pseudo-thecodont tooth implantation with teeth anchored within a socket of mineralized tissue by means of a mineralized periodontal ligament. Together, these data indicate that the moderate inclination of the erupting mosasaur tooth studied here is neither a result of postmortem displacement nor a character representative of snakes, but rather a shared character between Mosasaurs and other varanoids such as Heloderma. In

  2. Varanoid Tooth Eruption and Implantation Modes in a Late Cretaceous Mosasaur

    PubMed Central

    Liu, Min; Reed, David A.; Cecchini, Giancarlo M.; Lu, Xuanyu; Ganjawalla, Karan; Gonzales, Carol S.; Monahan, Richard; Luan, Xianghong

    2016-01-01

    Erupting teeth are some of the oldest witnesses of developmental processes in the vertebrate fossil record and provide an important resource for vertebrate cladistics. Here, we have examined a mosasaur jaw fragment from central Texas using ultrathin ground section histology and 3D tomographic imaging to assess features critical for the cladistic placement of mosasaurs among varanoids vs. snakes: (i) the orientation of replacement teeth compared to the major tooth axis, (ii) the occurrence of resorption pits, and (iii) the mode of tooth implantation/attachment to the tooth bearing element (TBE). The replacement tooth studied here developed in an inclined position slightly distal of the deciduous parent tooth, similar to another varanoid squamate, the Gila monster Heloderma suspectum. Ground sections and tomographs also demonstrated that the replacement tooth attachment apparatus was entirely intact and that there was no evidence of mechanical deformation. Sections and tomographs further illustrated that the replacement tooth was located within a bony crypt and the inclination of the crypt matched the inclination of the replacement tooth. These preparations also revealed the presence of a resorption pit within the boundaries of the deciduous tooth that surrounded the developing replacement tooth. This finding suggests that developing mosasaur teeth developed within the walls of resorption pits similar to varanoid tooth germs and unlike developing snake teeth which are surrounded by fibrous connective tissue integuments. Finally, mosasaurs featured pseudo-thecodont tooth implantation with teeth anchored within a socket of mineralized tissue by means of a mineralized periodontal ligament. Together, these data indicate that the moderate inclination of the erupting mosasaur tooth studied here is neither a result of postmortem displacement nor a character representative of snakes, but rather a shared character between Mosasaurs and other varanoids such as Heloderma. In

  3. Supernumerary Teeth in Primary Dentition and Early Intervention: A Series of Case Reports

    PubMed Central

    Bahadure, Rakesh N.; Thosar, Nilima; Jain, Eesha S.; Kharabe, Vidhi; Gaikwad, Rahul

    2012-01-01

    Supernumerary teeth are considered as one of the most significant dental anomalies during the primary and early mixed dentition stages. They are of great concern to the dentists and parents because of the eruption, occlusal, and esthetic problems they can cause. Supernumerary teeth occur more frequently in the permanent dentition but rarely in primary dentition. Mesiodens is the most common type of supernumerary teeth but rarely seen in lower arch. Early recognition and diagnosis of supernumerary teeth is important to prevent further complications in permanent dentition. Four cases of supernumerary teeth with mesiodens in upper and lower arch in primary dentition and their management have been discussed. PMID:22888456

  4. Primary failure of eruption (PFE)--clinical and molecular genetics analysis.

    PubMed

    Stellzig-Eisenhauer, Angelika; Decker, Eva; Meyer-Marcotty, Philipp; Rau, Christiane; Fiebig, Britta S; Kress, Wolfram; Saar, Kathrin; Rüschendorf, Franz; Hubner, Norbert; Grimm, Tiemo; Witt, Emil; Weber, Bernhard H F

    2010-01-01

    The term "primary failure of eruption" (PFE) refers to the complete or partial failure of a primary non-ankylosed tooth to erupt due to a disturbance of the eruption mechanism. Up to now, the molecular basis for this failure was unknown. Four families were studied in whom at least two members were affected by non-syndromic PFE as part of a clinical and molecular genetics study. Radiological diagnostics (OPTs) were carried out in all patients and their unaffected relatives (control group). The genetic analysis included a genomewide linkage analysis followed by direct DNA sequencing of positional candidate genes. Starting from the index patients, we were able to reconstruct pedigrees over two and/or three generations in the families that indicated an autosomal-dominant mode of inheritance of non-syndromic PFE. Fifteen patients were diagnosed with PFE. Gender distribution was nearly equal (7 female, 8 male). Molecular genetic analysis of the PTHR1 gene revealed three distinct heterozygous mutations (c.1050-3C>G; c.543+1G>A; c.463G>T). Unaffected persons exhibited no mutations. Knowledge of the genetic causes of non-syndromic PFE can now be used for the differential diagnosis of eruption failure. It permits affected family members to be identified early and may lead to new treatment possibilities in the long term. The genetically-verified diagnosis of "primary failure of eruption" can protect patients and orthodontists from years of futile treatment, because orthodontic treatment alone does not lead to success. Moreover, it has a negative influence on unaffected teeth and areas of the jaw.

  5. Mt. Spurr's 1992 eruptions

    USGS Publications Warehouse

    1993-01-01

    On 27 June, 1992, the Crater Peak vent on the south side of Mt. Spurr awoke from 39 years of dormancy and burst into sub-plinian eruption after 10 months of elevated seismicity. Two more eruptions followed in August and September. The volcano lies 125 km west of Anchorage, Alaska's largest city and an important international hub for air travel. The Alaska Volcano Observatory (AVO) was able to warn communities and the aviation industry well in advance of these eruptions.

  6. The trouble with teething--misdiagnosis and misuse of a topical medicament.

    PubMed

    Wilson, P H R; Mason, C

    2002-05-01

    For many clinicians and parents "teething" remains a convenient diagnosis to explain all manner of local and systemic upset in the young child. Many therapies are on the market to help alleviate the symptoms of primary tooth eruption. In this article we highlight the problems of "teething" as a diagnosis by presenting a case where an initial misdiagnosis of teething compromised a patient's life. The same patient then suffered from topical analgesic misuse during the recovery period.

  7. Three volcanoes erupt in Alaska

    USGS Publications Warehouse

    Miller, T.P.

    1987-01-01

    This is a description, illustrated with photographs, of the 1986 eruptions of Augustine, Pavlof and Akutan volcanoes. Augustine erupted pyroclastic flows, a large eruptive column, ash, and eventually a dome. Pavlof had an important Strombolian eruption which was one of the biggest in the last 30 years. Akutan had a small eruption at the same time. -A.Scarth

  8. Wisdom Teeth Management

    MedlinePlus

    ... of ten people have at least one impacted wisdom tooth. c. Complications such as infection (fig. a), damage ... teeth. a. b. How Serious Is an Impacted Wisdom Tooth? If left in the mouth, impacted wisdom teeth ...

  9. Large Prominence Eruption [video

    NASA Image and Video Library

    2014-10-07

    The STEREO (Behind) spacecraft captured this large prominence and corona mass ejection as they erupted into space (Sept. 26, 2014). By combining images from three instruments, scientists can see the eruption itself (in extreme UV light) as well as follow its progression over the period of about 13 hours with its two coronagraphs. Credit: NASA/Goddard/STEREO The STEREO (Behind) spacecraft captured this large prominence and corona mass ejection as they erupted into space (Sept. 26, 2014). By combining images from three instruments, scientists can see the eruption itself (in extreme UV light) as well as follow its progression over the period of about 13 hours with its two coronagraphs.

  10. Preservation of Involved Teeth Associated with Large Dentigerous Cysts

    PubMed Central

    Guven, Yeliz; Kasimoglu, Yelda; Soluk Tekkesin, Merva; Ulug, Dicle; Cankaya, Abdulkadir Burak; Tuna, Elif Bahar; Gencay, Koray; Aktoren, Oya

    2014-01-01

    Dentigerous cysts (DCs) are benign odontogenic cysts that are associated with the crowns of permanent teeth. The purpose of this study is to describe the management of DCs in four children. Four boys aged between 7 and 9 years were referred to our clinics with the complaints of intraoral alveolar swelling or facial asymmetry on the affected area. The panoramic radiographies showed large, well-defined radiolucent lesions associated with the deciduous teeth and displaced tooth buds. The treatment consisted of the extraction of the involved deciduous tooth and marsupialization of the cyst to allow eruption of the permanent tooth. Permanent teeth displaced by the DCs in three cases erupted spontaneously within one-year period. The case with horizontally displaced permanent tooth was managed by replantation. This is the first time that underlying permanent tooth in a DC case was intentionally replanted. PMID:27355026

  11. Timing of deciduous teeth emergence in Egyptian children.

    PubMed

    Soliman, N L; El-Zainy, M A; Hassan, R M; Aly, R M

    2011-11-01

    The existing eruption schedules for permanent and deciduous dentition are based on studies in industrialized countries. This study determined the dates of emergence of deciduous teeth in a cross-sectional sample of 1132 Egyptian infants aged 4-36 months selected from different governorates of Egypt. The dates of emergence of individual teeth were calculated using Probit analysis. The mandibular left and right incisors were the earliest teeth to emerge at a mean of 8.0 months in boys and 7.9 months in girls. The sequence of eruption followed a typical pattern. The average time from emergence of the first tooth to the last tooth was 17.8 months in the mandible and 15.8 months in the maxilla for boys and 22.1 and 20.1 months respectively for girls. Four active phases of emergence were identified and compared with data from other countries.

  12. Spontaneous tooth eruption after alveolar cleft osteoplasty using tissue-engineered bone: a case report.

    PubMed

    Pradel, Winnie; Tausche, Eve; Gollogly, James; Lauer, Günter

    2008-04-01

    To bridge the cleft in the alveolar bone and to allow for physiologic eruption of the canine teeth, alveolar bone grafting is often necessary in patients with cleft lips and palates. Instead of autogenous bone, biomaterial seeded with autogenous osteogenic cells has found some clinical application. However, so far no real functional proof has been available to demonstrate that this technique also allows further physiologic features such as tooth eruption to occur. This report describes the results of grafting tissue-engineered bone into the alveolar cleft of a 10-year-old boy. Immediate postoperative healing was uneventful. Eight months after grafting, erupting teeth had moved into the newly formed bone. Eighteen months postoperatively at the site where the tissue-engineered graft had been inserted, the canine had erupted spontaneously in its proper place. The data suggest that tissue-engineered bone can lead to the ossification of the alveolar cleft and allow for physiologic spontaneous tooth eruption.

  13. Mesiodistal root angulation of permanent teeth in children with mixed dentition and normal occlusion

    PubMed Central

    JESUINO, Flávia A. S.; COSTA, Luciane R.; VALLADARES-NETO, José

    2010-01-01

    Objective There is little information regarding the mesiodistal angulation of permanent teeth in mixed dentition. The aim of this study was to evaluate mesiodistal root angulation of permanent incisors, canines and first molars of 100 Brazilian children, using a new horizontal reference plane based on the midpoint of the intercuspation of primary canines and permanent first molars in panoramic radiographs during the mixed-dentition phase. Material and methods Children were equally divided between the genders with a mean age of 8.9 years (SD=0.76), normal occlusion and no eruptive disturbances. Results The angulation of the permanent maxillary first molars was close to the vertical, whereas the mandibular molars presented approximately 25 degrees of distal root angulation. The maxillary canines were the most distally angulated teeth, whereas the permanent mandibular canines were vertically positioned. The evaluation of the anterior maxillary area showed vertical position of permanent lateral, and central incisors with a slight distal angulation, whereas the permanent mandibular incisors tended to a mesial radicular convergence. Conclusions The proposed reference line could be useful in mixed dentition root angulation evaluation; there was a slight asymmetry in the mesiodistal angulation among homologous teeth, and also a small variation between the male and the female groups, but no difference between 8-and 10-year-old children. PMID:21308295

  14. Volcanic Eruptions and Climate

    NASA Astrophysics Data System (ADS)

    Robock, A.

    2012-12-01

    Large volcanic eruptions inject sulfur gases into the stratosphere, which convert to sulfate aerosols with an e-folding residence time of about one year. The radiative and chemical effects of these aerosol clouds produce responses in the climate system. Observations and numerical models of the climate system show that volcanic eruptions produce global cooling and were the dominant natural cause of climate change for the past millennium, on timescales from annual to century. Major tropical eruptions produce winter warming of Northern Hemisphere continents for one or two years, while high latitude eruptions in the Northern Hemisphere weaken the Asian and African summer monsoon. The Toba supereruption 74,000 years ago caused very large climate changes, affecting human evolution. However, the effects did not last long enough to produce widespread glaciation. An episode of four large decadally-spaced eruptions at the end of the 13th century C.E. started the Little Ice Age. Since the Mt. Pinatubo eruption in the Philippines in 1991, there have been no large eruptions that affected climate, but the cumulative effects of small eruptions over the past decade had a small effect on global temperature trends. The June 13, 2011 Nabro eruption in Eritrea produced the largest stratospheric aerosol cloud since Pinatubo, and the most of the sulfur entered the stratosphere not by direct injection, but by slow lofting in the Asian summer monsoon circulation. Volcanic eruptions warn us that while stratospheric geoengineering could cool the surface, reducing ice melt and sea level rise, producing pretty sunsets, and increasing the CO2 sink, it could also reduce summer monsoon precipitation, destroy ozone, allowing more harmful UV at the surface, produce rapid warming when stopped, make the sky white, reduce solar power, perturb the ecology with more diffuse radiation, damage airplanes flying in the stratosphere, degrade astronomical observations, affect remote sensing, and affect

  15. Solar Prominence Eruption

    NASA Technical Reports Server (NTRS)

    Moore, Ronald L.

    1998-01-01

    The prominence that erupts in a prominence eruption is a magnetic structure in the chromosphere and corona. It is visible in chromospheric images by virtue of chromospheric-temperature plasma suspended in the magnetic field, and belongs to that large class of magnetic structures appropriately called filaments because of their characteristic sinewy sigmoidal form. Hence, the term "filament eruption" is used interchangeably with the term "prominence eruption". The magnetic field holding a filament is prone to undergo explosive changes in configuration. In these upheavals, because the filament material is compelled by its high conductivity to ride with the magnetic field that threads it, this material is a visible tracer of the field motion. The part of the magnetic explosion displayed by the entrained filament material is the phenomenon known as a filament eruption, the topic of this article. This article begins with a description of basic observed characteristics of filament eruptions, with attention to the magnetic fields, flares, and coronal mass ejections in which erupting filaments are embedded. The present understanding of these characteristics in terms of the form and action of the magnetic field is then laid out by means of a rudimentary three-dimensional model of the field. The article ends with basic questions that this picture leaves unresolved and with remarks on the observations needed to probe these questions.

  16. SYMPATHETIC SOLAR FILAMENT ERUPTIONS

    SciTech Connect

    Wang, Rui; Liu, Ying D.; Zimovets, Ivan; Hu, Huidong; Yang, Zhongwei; Dai, Xinghua

    2016-08-10

    The 2015 March 15 coronal mass ejection as one of the two that together drove the largest geomagnetic storm of solar cycle 24 so far was associated with sympathetic filament eruptions. We investigate the relations between the different filaments involved in the eruption. A surge-like small-scale filament motion is confirmed as the trigger that initiated the erupting filament with multi-wavelength observations and using a forced magnetic field extrapolation method. When the erupting filament moved to an open magnetic field region, it experienced an obvious acceleration process and was accompanied by a C-class flare and the rise of another larger filament that eventually failed to erupt. We measure the decay index of the background magnetic field, which presents a critical height of 118 Mm. Combining with a potential field source surface extrapolation method, we analyze the distributions of the large-scale magnetic field, which indicates that the open magnetic field region may provide a favorable condition for F2 rapid acceleration and have some relation with the largest solar storm. The comparison between the successful and failed filament eruptions suggests that the confining magnetic field plays an important role in the preconditions for an eruption.

  17. Timing and sequence of primary tooth eruption in children with cleft lip and palate

    PubMed Central

    KOBAYASHI, Tatiana Yuriko; GOMIDE, Márcia Ribeiro; CARRARA, Cleide Felício de Carvalho

    2010-01-01

    Objective To determine the timing and sequence of eruption of primary teeth in children with complete bilateral cleft lip and palate. Material and Methods This cross-sectional study was conducted at the Hospital for Rehabilitation of Craniofacial Anomalies of the University of São Paulo, Bauru, SP, Brazil, with a sample of 395 children (128 girls and 267 boys) aged 0 to 48 months, with complete bilateral cleft lip and palate Results Children with complete bilateral clefts presented a higher mean age of eruption of all primary teeth for both arches and both genders, compared to children without clefts. This difference was statistically significant for all teeth, except for the maxillary first molar. Mean age of eruption of most teeth was lower for girls compared to boys. The greatest delay was found for the maxillary lateral incisor, which was the eighth tooth of children with clefts of both genders. Analyzing by gender, the maxillary lateral incisor was the eighth tooth to erupt in girls and the last in boys. Conclusion The results suggest an interference of the cleft on the timing and sequence of eruption of primary teeth. PMID:20856997

  18. Forced eruption and implant site development: soft tissue response.

    PubMed

    Mantzikos, T; Shamus, I

    1997-12-01

    The increased use of implants in orthodontics has stimulated interest in augmenting bone in patients who have deficient alveolar ridges that preclude ideal implant placement. A nonsurgical technique for increasing the amount of available bone for implant site development and fixture placement is orthodontic extrusion, or forced eruption. The concept of a tooth moving coronally by orthodontic means and the clinical alterations in the soft tissue architecture of the periodontium demonstrated during orthodontic extrusive movement of periodontally compromised teeth have demonstrated a direct relationship of pocket depth reduction, accompanied with an immature appearing tissue, "the red patch." This article will describe the periodontium during eruptive tooth movement.

  19. Unusually large erupted complex odontoma: A rare case report

    PubMed Central

    Kukreja, Rahul; Suma, Gundareddy N.; Yadav, Bhawna; Sharma, Havi

    2015-01-01

    Odontomas are nonaggressive, hamartomatous developmental malformations composed of mature tooth substances and may be compound or complex depending on the extent of morphodifferentiation or on their resemblance to normal teeth. Among them, complex odontomas are relatively rare tumors. They are usually asymptomatic in nature. Occasionally, these tumors become large, causing bone expansion followed by facial asymmetry. Odontoma eruptions are uncommon, and thus far, very few cases of erupted complex odontomas have been reported in the literature. Here, we report the case of an unusually large, painless, complex odontoma located in the right posterior mandible. PMID:25793183

  20. Diagnosing Common Skin Eruptions

    PubMed Central

    Enta, Tom

    1972-01-01

    The skin reacts to various insults in a limited number of ways. For this reason the etiologic diagnosis of a simple eruption may require some scrutiny on the part of the examiner. Only when a true diagnosis is arrived at, will the treatment be effective or successful. The author provides several examples of commonly seen eruptions and discusses their differential features. ImagesFig. 1Fig. 2Fig. 3Fig. 4Fig. 5Fig. 6 PMID:20468760

  1. SOLAR MULTIPLE ERUPTIONS FROM A CONFINED MAGNETIC STRUCTURE

    SciTech Connect

    Lee, Jeongwoo; Chae, Jongchul; Liu, Chang; Jing, Ju

    2016-09-20

    How eruption can recur from a confined magnetic structure is discussed based on the Solar Dynamics Observatory observations of the NOAA active region 11444, which produced three eruptions within 1.5 hr on 2012 March 27. The active region (AR) had the positive-polarity magnetic fields in the center surrounded by the negative-polarity fields around. Since such a distribution of magnetic polarity tends to form a dome-like magnetic fan structure confined over the AR, the multiple eruptions were puzzling. Our investigation reveals that this event exhibits several properties distinct from other eruptions associated with magnetic fan structures: (i) a long filament encircling the AR was present before the eruptions; (ii) expansion of the open–closed boundary (OCB) of the field lines after each eruption was suggestive of the growing fan-dome structure, and (iii) the ribbons inside the closed magnetic polarity inversion line evolved in response to the expanding OCB. It thus appears that in spite of multiple eruptions the fan-dome structure remained undamaged, and the closing back field lines after each eruption rather reinforced the fan-dome structure. We argue that the multiple eruptions could occur in this AR in spite of its confined magnetic structure because the filament encircling the AR was adequate for slipping through the magnetic separatrix to minimize the damage to its overlying fan-dome structure. The result of this study provides a new insight into the productivity of eruptions from a confined magnetic structure.

  2. Solar Multiple Eruptions from a Confined Magnetic Structure

    NASA Astrophysics Data System (ADS)

    Lee, Jeongwoo; Liu, Chang; Jing, Ju; Chae, Jongchul

    2016-09-01

    How eruption can recur from a confined magnetic structure is discussed based on the Solar Dynamics Observatory observations of the NOAA active region 11444, which produced three eruptions within 1.5 hr on 2012 March 27. The active region (AR) had the positive-polarity magnetic fields in the center surrounded by the negative-polarity fields around. Since such a distribution of magnetic polarity tends to form a dome-like magnetic fan structure confined over the AR, the multiple eruptions were puzzling. Our investigation reveals that this event exhibits several properties distinct from other eruptions associated with magnetic fan structures: (I) a long filament encircling the AR was present before the eruptions; (II) expansion of the open-closed boundary (OCB) of the field lines after each eruption was suggestive of the growing fan-dome structure, and (III) the ribbons inside the closed magnetic polarity inversion line evolved in response to the expanding OCB. It thus appears that in spite of multiple eruptions the fan-dome structure remained undamaged, and the closing back field lines after each eruption rather reinforced the fan-dome structure. We argue that the multiple eruptions could occur in this AR in spite of its confined magnetic structure because the filament encircling the AR was adequate for slipping through the magnetic separatrix to minimize the damage to its overlying fan-dome structure. The result of this study provides a new insight into the productivity of eruptions from a confined magnetic structure.

  3. Uneven distribution of enamel, dentine and cementum in cheek teeth of domestic horses (Equus caballus): A micro computed tomography study

    PubMed Central

    Kostrzewa, Kathrin; Kopke, Susan; Failing, Klaus; Staszyk, Carsten

    2017-01-01

    Background Hypsodont equine cheek teeth possess large dental crowns, resting partly in the bony alveolus. Over a horse’s life cheek teeth erupt continuously to compensate for occlusal wear of 3–4 mm per year. Parts of the crown initially resting in the bony alveolus become progressively exposed at the occlusal surface with time. Hitherto, it is unclear whether the typical structure of the equine occlusal surface, composed of a complex arrangement of enamel, dentin and cementum, remains constant or undergoes structural changes with age. Therefore, we tested the hypothesis that the occlusal surface composition does not remain constant by a quantitative analysis of the dental substances at multiple levels along the dental crown of equine cheek teeth. Methods Micro-computed tomography scans of 20 upper cheek teeth and 16 lower cheek teeth from 19 domestic horses were morphologically analysed using imaging and measurement software. Area for individual dental substances was measured at different levels from the apex to the occlusal surface. The data was statistically analysed to detect changes in the area of individual substance along the dental crown. The area of peripheral cementum was measured separately for levels inside and outside the bony alveolus. Results In both, upper and lower cheek teeth, enamel area decreased in an apical direction, while dentine area increased. Peripheral Cementum increased dramatically in the occlusal/coronal extra-alveolar position. Conclusion With increasing age the occlusal surface content of dentine increases while the content of enamel decreases. These changes are considered relevant for the detailed explanation of forage disruption in horses as well as for the recommendation of concepts in equine dentistry. PMID:28813496

  4. Uneven distribution of enamel, dentine and cementum in cheek teeth of domestic horses (Equus caballus): A micro computed tomography study.

    PubMed

    Englisch, Lauritz Martin; Kostrzewa, Kathrin; Kopke, Susan; Failing, Klaus; Staszyk, Carsten

    2017-01-01

    Hypsodont equine cheek teeth possess large dental crowns, resting partly in the bony alveolus. Over a horse's life cheek teeth erupt continuously to compensate for occlusal wear of 3-4 mm per year. Parts of the crown initially resting in the bony alveolus become progressively exposed at the occlusal surface with time. Hitherto, it is unclear whether the typical structure of the equine occlusal surface, composed of a complex arrangement of enamel, dentin and cementum, remains constant or undergoes structural changes with age. Therefore, we tested the hypothesis that the occlusal surface composition does not remain constant by a quantitative analysis of the dental substances at multiple levels along the dental crown of equine cheek teeth. Micro-computed tomography scans of 20 upper cheek teeth and 16 lower cheek teeth from 19 domestic horses were morphologically analysed using imaging and measurement software. Area for individual dental substances was measured at different levels from the apex to the occlusal surface. The data was statistically analysed to detect changes in the area of individual substance along the dental crown. The area of peripheral cementum was measured separately for levels inside and outside the bony alveolus. In both, upper and lower cheek teeth, enamel area decreased in an apical direction, while dentine area increased. Peripheral Cementum increased dramatically in the occlusal/coronal extra-alveolar position. With increasing age the occlusal surface content of dentine increases while the content of enamel decreases. These changes are considered relevant for the detailed explanation of forage disruption in horses as well as for the recommendation of concepts in equine dentistry.

  5. Incremental enamel development in modern human deciduous anterior teeth.

    PubMed

    Mahoney, Patrick

    2012-04-01

    This study reconstructs incremental enamel development for a sample of modern human deciduous mandibular (n = 42) and maxillary (n = 42) anterior (incisors and canines) teeth. Results are compared between anterior teeth, and with previous research for deciduous molars (Mahoney: Am J Phys Anthropol 144 (2011) 204-214) to identify developmental differences along the tooth row. Two hypotheses are tested: Retzius line periodicity will remain constant in teeth from the same jaw and range from 6 to 12 days among individuals, as in human permanent teeth; daily enamel secretion rates (DSRs) will not vary between deciduous teeth, as in some human permanent tooth types. A further aim is to search for links between deciduous incremental enamel development and the previously reported eruptionsequence. Retzius line periodicity in anterior teeth ranged between 5 and 6 days, but did not differ between an incisor and molar of one individual. Intradian line periodicity was 12 h. Mean cuspal DSRs varied slightly between equivalent regions along the tooth row. Mandibular incisors initiated enamel formation first, had the fastest mean DSRs, the greatest prenatal formation time, and based upon prior studies are the first deciduous tooth to erupt. Relatively rapid development in mandibular incisors in advance of early eruption may explain some of the variation in DSRs along the tooth row that cannot be explained by birth. Links between DSRs, enamel initiation times, and the deciduous eruption sequence are proposed. Anterior crown formation times presented here can contribute toward human infant age-at-death estimates. Regression equations for reconstructing formation time in worn incisors are given. Copyright © 2012 Wiley Periodicals, Inc.

  6. Effects of traumatic dental injuries to primary teeth on permanent teeth--a clinical follow-up study.

    PubMed

    de Amorim, Lilian de Fátima Guedes; Estrela, Carlos; da Costa, Luciane Ribeiro Resende Sucasas

    2011-04-01

    This study evaluated the prevalence of developmental sequelae to permanent teeth (DSP) after traumatic dental injuries to primary teeth (TDI-1) and their association with age, gender, type of injury, recurrence of injury and post-traumatic damage to primary teeth. Dental records of 2725 children treated from February 1993 to December 2008 in a private pediatric dental clinic were examined. A total of 308 records had 412 primary teeth that sustained traumatic injuries. Age at the time of injury ranged from 4 months to 7 years. A chi-squared test and logistic regression were used for statistical analyses. One hundred forty-eight children (241 teeth) were followed up until the eruption of the permanent successor. The prevalence of DSP was 22.4%. Discoloration and hypoplasia were the most frequent abnormalities (74.1%), followed by eruption disorders (25.9%). Age at the time of TDI-1 was the only variable significantly associated with DSP. Sequelae were most prevalent among children who suffered an injury between 1 and 3 years of age. Children who sustain traumatic dental injuries should be followed up regularly for an early diagnosis and treatment of possible DSP. © 2010 John Wiley & Sons A/S.

  7. Eruptive cheilitis: a new adverse effect in reactive HIV-positive patients subjected to high activity antiretroviral therapy (HAART). Presentation of six clinical cases.

    PubMed

    Casariego, Z; Pombo, T; Pérez, H; Patterson, P

    2001-01-01

    A variety of exfoliative cheilitis has been observed in reactive HIV-1 patients subjected to high activity antiretroviral therapy (HAART). The lesions exhibit exfoliation, crater formation, fissuring, erosions and/or the formation of papules, vesicles and blisters associated to erythema and edema. The condition is not included in the 1993 EEC Clearinghouse classification (1) of oral lesions associated with HIV infection. In an earlier series of 1899 patients (2), we failed to observe this pathology and have only found one similar case described in the literature to date (3). We present a series of 6 patients with HIV infection and morpho-histological alterations of the labial semimucosa, subjected to HAART. The 6 patients were selected from among 20 HIV-positive individuals treated in our Infectious Diseases Unit with a combination of nucleoside and non-nucleoside reverse transcriptase inhibitors and protease inhibitors requiring stomatological care for painful lesions of the lips and oral cavity. The study was conducted over a 6-month period between May and October 1998. An analysis was made of the case histories, CD4-positive cell counts and viral load. The stomatological explorations were completed with biopsies, hematoxylin-eosin staining and immunohistochemical studies involving AE1 and AE3 monoclonal antibodies, vimentin, protein S-100, carcinoembryonic antigen (CEA), laminin, CD8, HLA-DR, BM-1 and CD31 markers. At the time of detection of the oral lesions, the patients had received different combinations of the following antiretroviral treatments: stavudine (D4T), zalcitabine (DDC), didanosine (DDI), zidovudine (AZT), lamivudine (3TC), nelfinavir (NFV), saquinavir (SQV), ritonavir (RTV), hydroxyurea (HU), indinavir (IDN) and efavirenz (EFV). There were four males and two females (age range 31-42 years). The CD4-positive and viral load ranges were 70-330 cells/mm3 and 200-500,200 copies, respectively. Stomatologic manifestations: The oral clinical

  8. Volcanic eruptions on Io

    NASA Astrophysics Data System (ADS)

    Strom, R. G.; Schneider, N. M.; Terrile, R. J.; Cook, A. F.; Hansen, C.

    1981-09-01

    Nine eruption plumes which were observed during the Voyager 1 encounter with Io are discussed. During the Voyager 2 encounter, four months later, eight of the eruptions were still active although the largest became inactive sometime between the two encounters. Plumes range in height from 60 to over 300 km with corresponding ejection velocities of 0.5 to 1.0 km/s and plume sources are located on several plains and consist of fissures or calderas. The shape and brightness distribution together with the pattern of the surface deposition on a plume 3 is simulated by a ballistic model with a constant ejection velocity of 0.5 km/s and ejection angles which vary from 0-55 deg. The distribution of active and recent eruptions is concentrated in the equatorial regions and indicates that volcanic activity is more frequent and intense in the equatorial regions than in the polar regions. Due to the geologic setting of certain plume sources and large reservoirs of volatiles required for the active eruptions, it is concluded that sulfur volcanism rather than silicate volcanism is the most likely driving mechanism for the eruption plumes.

  9. Eruption column physics

    SciTech Connect

    Valentine, G.A.

    1997-03-01

    In this paper the author focuses on the fluid dynamics of large-scale eruption columns. The dynamics of these columns are rooted in multiphase flow phenomena, so a major part of the paper sets up a foundation on that topic that allows one to quickly assess the inherent assumptions made in various theoretical and experimental approaches. The first part is centered on a set of complex differential equations that describe eruption columns, but the focus is on a general understanding of important physical processes rather than on the mathematics. The author discusses briefly the relative merits and weaknesses of different approaches, emphasizing that the largest advances in understanding are made by combining them. He then focuses on dynamics of steady eruption columns and then on transient phenomena. Finally he briefly reviews the effects of varying behavior of the ambient medium through which an eruption column moves. These final sections will emphasize concepts and a qualitative understanding of eruption dynamics. This paper relies on principles of continuum mechanics and transport processes but does not go into detail on the development of those principles. 36 refs., 36 figs., 3 tabs.

  10. Volcanic eruptions on Io

    NASA Technical Reports Server (NTRS)

    Strom, R. G.; Schneider, N. M.; Terrile, R. J.; Hansen, C.; Cook, A. F.

    1981-01-01

    Nine eruption plumes which were observed during the Voyager 1 encounter with Io are discussed. During the Voyager 2 encounter, four months later, eight of the eruptions were still active although the largest became inactive sometime between the two encounters. Plumes range in height from 60 to over 300 km with corresponding ejection velocities of 0.5 to 1.0 km/s and plume sources are located on several plains and consist of fissures or calderas. The shape and brightness distribution together with the pattern of the surface deposition on a plume 3 is simulated by a ballistic model with a constant ejection velocity of 0.5 km/s and ejection angles which vary from 0-55 deg. The distribution of active and recent eruptions is concentrated in the equatorial regions and indicates that volcanic activity is more frequent and intense in the equatorial regions than in the polar regions. Due to the geologic setting of certain plume sources and large reservoirs of volatiles required for the active eruptions, it is concluded that sulfur volcanism rather than silicate volcanism is the most likely driving mechanism for the eruption plumes.

  11. [Mean age of dental eruption in a school-age population analyzed by 2 methods].

    PubMed

    Valdez Penagos, Remedios Guadalupe; Sánchez Acuña, Gabriela; Romo Pinales, María Rebeca; Miranda Campos, Alhelí; Tovar Rodríguez, Alma Aurora; Yánez Valdivia, Daniel

    Because dental eruption is the result of a series of physiological events, it is important to acknowledge precisely the mean age of exfoliation and eruption of each dental organ. This is useful to establish diagnostic, preventive and treatment criteria. The aim of this study was to compare the cross-sectional and cohort methods toward estimating the average age of dental eruption. The study sample was comprised of 524 school-age children from the State of Mexico (273 females and 251 males). Only permanent teeth were surveyed: the first upper molar and central and lateral incisors and the first lower molar. The cohort was observed during a 3-year period until the tooth budded. Dental mirror, tongue depressor and day light were used. Cross-sectional method consisted of permanent teeth observed after the first year. In both methods, teeth budded first in females. The average ages of dental eruption according to both methods did not show statistical difference in 88% of the teeth. Measurement of the age of dental eruption through cross-sectional method provides reliable data in relation to the cohort method. Copyright © 2015 Hospital Infantil de México Federico Gómez. Publicado por Masson Doyma México S.A. All rights reserved.

  12. Acneiform facial eruptions

    PubMed Central

    Cheung, Melody J.; Taher, Muba; Lauzon, Gilles J.

    2005-01-01

    OBJECTIVE To summarize clinical recognition and current management strategies for four types of acneiform facial eruptions common in young women: acne vulgaris, rosacea, folliculitis, and perioral dermatitis. QUALITY OF EVIDENCE Many randomized controlled trials (level I evidence) have studied treatments for acne vulgaris over the years. Treatment recommendations for rosacea, folliculitis, and perioral dermatitis are based predominantly on comparison and open-label studies (level II evidence) as well as expert opinion and consensus statements (level III evidence). MAIN MESSAGE Young women with acneiform facial eruptions often present in primary care. Differentiating between morphologically similar conditions is often difficult. Accurate diagnosis is important because treatment approaches are different for each disease. CONCLUSION Careful visual assessment with an appreciation for subtle morphologic differences and associated clinical factors will help with diagnosis of these common acneiform facial eruptions and lead to appropriate management. PMID:15856972

  13. Eruptions from the Sun

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2015-11-01

    The Sun often exhibits outbursts, launching material from its surface in powerful releases of energy. Recent analysis of such an outburst captured on video by several Sun-monitoring spacecraft may help us understand the mechanisms that launch these eruptions.Many OutburstsSolar jets are elongated, transient structures that are thought to regularly release magnetic energy from the Sun, contributing to coronal heating and solar wind acceleration. Coronal mass ejections (CMEs), on the other hand, are enormous blob-like explosions, violently ejecting energy and mass from the Sun at incredible speeds.But could these two types of events actually be related? According to a team of scientists at the University of Science and Technology of China, they may well be. The team, led by Jiajia Liu, has analyzed observations of a coronal jet that they believe prompted the launch of a powerful CME.Observing an ExplosionGif of a movie of the CME, taken by the Solar Dynamics Observatorys Atmospheric Imaging Assembly at a wavelength of 304. The original movie can be found in the article. [Liu et al.]An army of spacecraft was on hand to witness the event on 15 Jan 2013 including the Solar Dynamics Observatory (SDO), the Solar and Heliospheric Observatory (SOHO), and the Solar Terrestrial Relations Observatory (STEREO). The instruments on board these observatories captured the drama on the northern limb of the Sun as, at 19:32 UT, a coronal jet formed. Just eight minutes later, a powerful CME was released from the same active region.The fact that the jet and CME occurred in the same place at roughly the same time suggests theyre related. But did the initial motions of the CME blob trigger the jet? Or did the jet trigger the CME?Tying It All TogetherIn a recently published study, Liu and collaborators analyzed the multi-wavelength observations of this event to find the heights and positions of the jet and CME. From this analysis, they determined that the coronal jet triggered the release

  14. Malocclusion of teeth

    MedlinePlus

    ... Treatments may include: Braces or other appliances: Metal bands are placed around some teeth, or metal, ceramic, ... www.urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. ...

  15. Malocclusion (Misaligned Teeth)

    MedlinePlus

    ... Drug Information, Search Drug Names, Generic and Brand Natural Products, Search Drug Interactions ... Teeth) By David F. Murchison, DDS, MMS, Clinical Professor, Department of Biological Sciences, The University of Texas at Dallas; Clinical Professor, ...

  16. ASTER Images Merapi Continuing Eruption

    NASA Image and Video Library

    2010-11-18

    This thermal infrared image from NASA Terra spacecraft of Merapi continuing eruption has been processed to reveal the dominant presence of volcanic ash in the eruption plume and clouds, displayed in dark red. The warm volcanic flow appears bright.

  17. RhBMP-7 improves survival and eruption in a growing tooth avulsion trauma model.

    PubMed

    Springer, Ingo N G; Açil, Yahya; Spies, Christian; Jepsen, Sören; Warnke, Patrick H; Bolte, Hendrik; Kuchenbecker, Solveig; Russo, Paul A J; Wiltfang, Jörg; Terheyden, Hendrik

    2005-10-01

    Long-term loss of avulsed and replanted teeth is a frequent clinical problem. Bone morphogenetic protein-7 (BMP 7) induces cementogenesis in periodontitis-associated periodontal ligament (PDL) defects. This study's aim was to assess the utility of rhBMP 7 in a tooth avulsion trauma model in growing individuals. Immature primary incisors of 12 minipigs were extracted. PDL and cementum were removed either partially (group 1: 4 mm2 [n=28 teeth]; group 2: 16 mm2 [n=26 teeth]) or totally (group 3 [n=26 teeth]). 500 microg rhBMP 7/g collagen matrix was applied to the teeth from one side while the corresponding teeth on the contralateral side served as controls (split mouth model). After an experimental period of 4 months, microradiography, fluorescence and light microscopy of nondecalcified sections were performed. All teeth of group 1 survived and all teeth of group 3 were lost, whether rhBMP-7 was applied or not. In group 2, nine out of ten teeth survived when rhBMP-7 was applied and four out of ten teeth were lost when rhBMP-7 was not applied. In the presence of rhBMP-7, eruption of teeth in group 2 was significantly improved (difference [median]: 5 mm, P<0.05, n=6). Even though there was a tendency towards increased deposition rates of cementum under rhBMP-7, this difference was not significant (Wilcoxon: P>0.05, ANOVA: P=0.002; n=6/group). In conclusion, rhBMP-7 improved survival rates and eruption of replanted teeth in growing individuals. No adverse effects were seen. Based on the present results, future clinical trials appear to be warranted.

  18. Extraction of primary (baby) teeth for unerupted palatally displaced permanent canine teeth in children.

    PubMed

    Parkin, Nicola; Benson, Philip E; Shah, Anwar; Thind, Bikram; Marshman, Zoe; Glenroy, Gillian; Dyer, Fiona

    2009-04-15

    The permanent canine tooth in the upper (maxillary) jaw sometimes does not erupt into the mouth correctly. In about 1% to 3% of the population these teeth will be diverted into the roof of the mouth (palatally). It has been suggested that if the deciduous canine is removed at the right time this palatal eruption might be avoided. To evaluate the effect of extracting the primary maxillary canine on the eruption of the palatally ectopic maxillary permanent canine. We searched the Cochrane Oral Health Group's Trials Register (to April 2008); CENTRAL (The Cochrane Library 2008, Issue 3); MEDLINE (1966 to April 2008); EMBASE (1980 to April 2008). There were no language restrictions. Authors of trials were contacted for further data. Trials were selected if they met the following criteria: a randomised or quasi-randomised controlled trial, involving the extraction of the primary maxillary canine and assessing eruption/non-eruption of the palatally displaced maxillary permanent canine. Seven review authors independently, in duplicate, examined the studies found in the search. The primary outcome was the reported prevalence of eruption or non-eruption of the ectopic permanent canine into the mouth following observation or intervention. Results were to be expressed as risk ratios for dichotomous outcomes with 95% confidence intervals and mean differences for continuous outcomes. Heterogeneity was to be investigated, including both clinical and methodological factors. The search identified 324 publications of which 295 were excluded after reviewing the abstract. Full articles were obtained for the remaining 31, of which 19 were non-English and required translation. Three reports of two randomised controlled trials were identified for possible inclusion in the review; however, the data in the publications were not presented in a form that could be usable and the authors have been contacted for further details. There is currently no evidence to support the extraction of the

  19. Volcanic Eruptions and Climate

    NASA Technical Reports Server (NTRS)

    LeGrande, Allegra N.; Anchukaitis, Kevin J.

    2015-01-01

    Volcanic eruptions represent some of the most climatically important and societally disruptive short-term events in human history. Large eruptions inject ash, dust, sulfurous gases (e.g. SO2, H2S), halogens (e.g. Hcl and Hbr), and water vapor into the Earth's atmosphere. Sulfurous emissions principally interact with the climate by converting into sulfate aerosols that reduce incoming solar radiation, warming the stratosphere and altering ozone creation, reducing global mean surface temperature, and suppressing the hydrological cycle. In this issue, we focus on the history, processes, and consequences of these large eruptions that inject enough material into the stratosphere to significantly affect the climate system. In terms of the changes wrought on the energy balance of the Earth System, these transient events can temporarily have a radiative forcing magnitude larger than the range of solar, greenhouse gas, and land use variability over the last millennium. In simulations as well as modern and paleoclimate observations, volcanic eruptions cause large inter-annual to decadal-scale changes in climate. Active debates persist concerning their role in longer-term (multi-decadal to centennial) modification of the Earth System, however.

  20. Volcanic Eruptions in Kamchatka

    NASA Image and Video Library

    2007-04-30

    One of the most volcanically active regions of the world is the Kamchatka Peninsula in eastern Siberia, Russia. It is not uncommon for several volcanoes to be erupting at the same time. NASA Terra satellite acquired this image on April 26, 2007

  1. Coevolutionary patterning of teeth and taste buds.

    PubMed

    Bloomquist, Ryan F; Parnell, Nicholas F; Phillips, Kristine A; Fowler, Teresa E; Yu, Tian Y; Sharpe, Paul T; Streelman, J Todd

    2015-11-03

    Teeth and taste buds are iteratively patterned structures that line the oro-pharynx of vertebrates. Biologists do not fully understand how teeth and taste buds develop from undifferentiated epithelium or how variation in organ density is regulated. These organs are typically studied independently because of their separate anatomical location in mammals: teeth on the jaw margin and taste buds on the tongue. However, in many aquatic animals like bony fishes, teeth and taste buds are colocalized one next to the other. Using genetic mapping in cichlid fishes, we identified shared loci controlling a positive correlation between tooth and taste bud densities. Genome intervals contained candidate genes expressed in tooth and taste bud fields. sfrp5 and bmper, notable for roles in Wingless (Wnt) and bone morphogenetic protein (BMP) signaling, were differentially expressed across cichlid species with divergent tooth and taste bud density, and were expressed in the development of both organs in mice. Synexpression analysis and chemical manipulation of Wnt, BMP, and Hedgehog (Hh) pathways suggest that a common cichlid oral lamina is competent to form teeth or taste buds. Wnt signaling couples tooth and taste bud density and BMP and Hh mediate distinct organ identity. Synthesizing data from fish and mouse, we suggest that the Wnt-BMP-Hh regulatory hierarchy that configures teeth and taste buds on mammalian jaws and tongues may be an evolutionary remnant inherited from ancestors wherein these organs were copatterned from common epithelium.

  2. Coevolutionary patterning of teeth and taste buds

    PubMed Central

    Bloomquist, Ryan F.; Parnell, Nicholas F.; Phillips, Kristine A.; Fowler, Teresa E.; Yu, Tian Y.; Sharpe, Paul T.; Streelman, J. Todd

    2015-01-01

    Teeth and taste buds are iteratively patterned structures that line the oro-pharynx of vertebrates. Biologists do not fully understand how teeth and taste buds develop from undifferentiated epithelium or how variation in organ density is regulated. These organs are typically studied independently because of their separate anatomical location in mammals: teeth on the jaw margin and taste buds on the tongue. However, in many aquatic animals like bony fishes, teeth and taste buds are colocalized one next to the other. Using genetic mapping in cichlid fishes, we identified shared loci controlling a positive correlation between tooth and taste bud densities. Genome intervals contained candidate genes expressed in tooth and taste bud fields. sfrp5 and bmper, notable for roles in Wingless (Wnt) and bone morphogenetic protein (BMP) signaling, were differentially expressed across cichlid species with divergent tooth and taste bud density, and were expressed in the development of both organs in mice. Synexpression analysis and chemical manipulation of Wnt, BMP, and Hedgehog (Hh) pathways suggest that a common cichlid oral lamina is competent to form teeth or taste buds. Wnt signaling couples tooth and taste bud density and BMP and Hh mediate distinct organ identity. Synthesizing data from fish and mouse, we suggest that the Wnt-BMP-Hh regulatory hierarchy that configures teeth and taste buds on mammalian jaws and tongues may be an evolutionary remnant inherited from ancestors wherein these organs were copatterned from common epithelium. PMID:26483492

  3. Spontaneous Eruption of Premolar Associated with a Dentigerous Cyst

    PubMed Central

    Luna, Anibal Henrique Barbosa

    2016-01-01

    Dentigerous cyst (DC) is the second most common odontogenic cyst with greater incidence in young patients. It presents as a unilocular, asymptomatic radiolucency involving the crown of an impacted tooth, commonly noticed in X-rays to investigate absence, wrong tooth position, or delay in the chronology of eruption. Decompression/marsupialization (D/M) is the most implemented treatment, especially when preserving the tooth involved is advised. The aim of this study is to discuss the DC characteristics that contribute to spontaneous eruption of premolars, by reporting the case of a conservative treatment of DC. This eruption depends on factors such as age, angulation of inclusion, rate of root formation, depth of inclusion, and eruption space. This paper reports the case of a 10-year-old patient with a radiolucent lesion diagnosed as DC involving element 35, which erupted as a result of treatment. The patient was observed during 1 year and 6 months. PMID:27313912

  4. Eruption of Kliuchevskoi volcano

    NASA Image and Video Library

    1994-10-05

    STS068-155-094 (30 September-11 October 1994) --- (Kliuchevskoi Volcano) The crewmembers used a Linhof large format Earth observation camera to photograph this nadir view of the Kamchatka peninsula's week-old volcano. The eruption and the follow-up environmental activity was photographed from 115 nautical miles above Earth. Six NASA astronauts spent a week and a half aboard the Space Shuttle Endeavour in support of the Space Radar Laboratory 2 (SRL-2) mission.

  5. Nyamuragira Volcano Erupts

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Nyamuragira volcano erupted on July 26, 2002, spewing lava high into the air along with a large plume of steam, ash, and sulfur dioxide. The 3,053-meter (10,013-foot) volcano is located in eastern Congo, very near that country's border with Rwanda. Nyamuragira is the smaller, more violent sibling of Nyiragongo volcano, which devastated the town of Goma with its massive eruption in January 2002. Nyamuragira is situated just 40 km (24 miles) northeast of Goma. This true-color image was acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS), flying aboard NASA's Terra satellite, on July 28, 2002. Nyamuragira is situated roughly in the center of this scene, roughly 100 km south of Lake Edward and just north of Lake Kivu (which is mostly obscured by the haze from the erupting volcano and the numerous fires burning in the surrounding countryside). Due south of Lake Kivu is the long, narrow Lake Tanganyika running south and off the bottom center of this scene.

  6. Geyser's Eruptive Activity in Broadband Seismic Records

    NASA Astrophysics Data System (ADS)

    Kugaenko, Yulia; Saltykov, Vadim

    2010-05-01

    River on June 3, 2007 and new dammed lake was formed in the Valley of the Geysers; a part of geysers has been destroyed and flooded). Some days the Big geyser was on the depth near 10 m. It got free from water in beginning of September, 2007 and reactivated. In September, 2009 eruptions were very active with the interval between them 55-60 min without quiet mode or pause in boiling. - The Pearl geyser eruptions are near 5 min., main cycle is 300-360 min. The height of fountain is 8-10 m. It is one of most picturesque geysers in the Valley. - The Gap geyser is the cone type geyser with stable rate and relatively shot cycle (33-34 min.). Eruptions are near 5 min. and not strong. The main feature of the Gap geyser is absence of boiling-effusion mode before eruption. For the large Big and Pearl geysers low-frequency seismic response on geyser's eruption was detected. Seismometer shows surface deformation caused by water-steam burst from the vent (or geyser eruption) with the period about 10-12 min. Slow vertical and radial displacements were recorded as travel of instrument's mass position. It was shown, that eruptions of the Big geyser are not constant. We can observe it in seismic records at different frequency bands. Some eruptions are weaker then other in low-frequency band (lesser then 0.01 Hz), but approximately similar for the range 20-50 Hz. It means possible deep variations of thermal supply. The weak short-period Gap geyser has high stability of eruptive activity in seismic records at frequency band 1-50 Hz. The correlation between envelops for different geyser's cycles exceeds 0.9. It demonstrates the invariability of thermal and water supply of this geyser. The seismic record of the eruption cycle starts with the activity increasing in intensity and amplitude, and than signal amplitude gradually decays until the final moment before an eruption. The amplitude decay was explained by (Kieffer, 1984) by an increased acoustic impedance mismatch between the two

  7. A survey of natal and neonatal teeth in newborn infants.

    PubMed

    Wang, Chun-Hsiang; Lin, Yai-Tin; Lin, Yng-Tzer J

    2017-03-01

    Since there is no comprehensive research of natal and neonatal teeth in Taiwan, careful investigation of natal or neonatal teeth is worthy of being studied. This retrospective study investigated the prevalence and clinical characteristics of natal or neonatal teeth in a hospital setting, and analyzed the possible relationships between investigated variables of the natal or neonatal teeth. All of the 12,019 infants born at an assigned hospital between January 1, 2008 and December 31, 2014 were investigated for natal or neonatal teeth. The identified individuals were reviewed for systemic diseases. Dental examinations included the location, clinical appearance, and degree of mobility. A positive family history of natal or neonatal teeth and mother's physical condition before delivery were also investigated. The collected data were analyzed using Fisher's exact test. Thirty infants were identified with a total of 43 natal or neonatal teeth (females, 19; males, 11). Most of the teeth were in the mandibular primary incisor position (97.6%). A radiographic examination confirmed that not all of the natal or neonatal teeth were supernumerary. No significant differences were observed between males and females in tooth morphology, positive family history, and treatment methods (p > 0.05) or between normal and conical shapes in positive family history, premature infant, mother's physical condition before delivery, and treatment methods (p > 0.05). Most of the natal or neonatal teeth were in the mandibular primary incisor position and not all of them were supernumerary. No gender differences were found in tooth morphology, positive family history, and treatment methods. The tooth morphology was not significantly related to a positive family history, premature delivery, or the mother's physical condition before delivery. Copyright © 2016. Published by Elsevier B.V.

  8. Eruption rates in explosive eruptions: Ground truth and models

    NASA Astrophysics Data System (ADS)

    Tumi Gudmundsson, Magnus; Durig, Tobias; Höskuldsson, Ármann; Thordarson, Thorvaldur; Larsen, Gudrún; Óladóttir, Bergrún A.; Högnadóttir, Thórdís; Oddsson, Björn; Björnsson, Halldór; Gudmundsdóttir, Esther R.

    2015-04-01

    Estimations of eruption rates in explosive eruptions are difficult and error margins are invariably high. In small to moderate sized eruptions effects of wind on plume height can be large and in larger eruptions observations are often difficult due to masking of source by low cloud, pyroclastic density currents and monitoring system saturation. Several medium-sized explosive eruptions in recent years have been an important in sparking off intense research on e.g. atmosphere-plume interaction and associated effects of wind on plume height. Other methods that do not rely on plume height are e.g. infrared satellite monitoring of atmospheric loading of fine tephra, infrasound, analysis of video recordings from vents, and it has been suggested that co-eruptive tilt-meter deformation data can predict eruption intensity. The eruptions of Eyjafjallajökull in 2010 and Grímsvötn in 2011 provided a wealth of data that potentially can be of use in developing constraints of eruption rates in explosive eruptions. A key parameter in all such comparisons between models and data is as detailed knowledge as possible on tephra fallout. For both Eyjafjallajökull and Grímsvötn intensive field efforts took place to map out the deposits during and immediately after the eruptions. The resulting maps cover both individual phases as well as total fallout. Comparison of these data with plume-based and other models of mass discharge rates is presently work in progress. A desirable future aim is near real time estimates of mass eruption rates based several of the parameters mentioned above. This type of work is currently ongoing within the framework of the EU-funded supersite project FUTUREVOLC.

  9. ClC-7 Deficiency Impairs Tooth Development and Eruption.

    PubMed

    Wang, He; Pan, Meng; Ni, Jinwen; Zhang, Yanli; Zhang, Yutao; Gao, Shan; Liu, Jin; Wang, Zhe; Zhang, Rong; He, Huiming; Wu, Buling; Duan, Xiaohong

    2016-02-01

    CLCN7 gene encodes the voltage gated chloride channel 7 (ClC-7) in humans. The mutations in CLCN7 have been associated with osteopetrosis in connection to the abnormal osteoclasts functions. Previously, we found that some osteopetrosis patients with CLCN7 mutations suffered from impacted teeth and root dysplasia. Here we set up two in vivo models under a normal or an osteoclast-poor environment to investigate how ClC-7 affects tooth development and tooth eruption. Firstly, chitosan-Clcn7-siRNA nanoparticles were injected around the first maxillary molar germ of newborn mice and caused the delay of tooth eruption and deformed tooth with root dysplasia. Secondly, E13.5 molar germs infected with Clcn7 shRNA lentivirus were transplanted under the kidney capsule and presented the abnormal changes in dentin structure, periodontal tissue and cementum. All these teeth changes have been reported in the patients with CLCN7 mutation. In vitro studies of ameloblasts, odontoblasts and dental follicle cells (DFCs) were conducted to explore the involved mechanism. We found that Clcn7 deficiency affect the differentiation of these cells, as well as the interaction between DFCs and osteoclasts through RANKL/OPG pathway. We conclude that ClC-7 may affect tooth development by directly targeting tooth cells, and regulate tooth eruption through DFC mediated osteoclast pathway.

  10. Continuous tooth eruption in Australian aboriginal skulls.

    PubMed

    Danenberg, P J; Hirsch, R S; Clarke, N G; Leppard, P I; Richards, L C

    1991-07-01

    Increases in the distance from the cemento-enamel junction to the alveolar crest (CEJ-AC) have often been attributed to senile atrophy of the bone or to the effects of periodontitis, without reference to the condition of the alveolar crest. This study investigated the relationship between CEJ-AC distance, tooth wear, gender, site of the CEJ-AC measurements, and age in 161 pre-white-contact Australian aboriginal skulls. Individual teeth were included in the study when there was no evidence of dehiscence, periodontitis, or abscess cavity formation in the supporting alveolar bone. The CEJ-AC distances increased as the severity of attrition increased; in male skulls, CEJ-AC distances were greater than in female skulls for all categories of tooth wear. In general, CEJ-AC distances measured on the mesial aspects of teeth were greater than those recorded distally; lingual distances generally exceeded buccal recordings. The best explanation of these findings and similar reports in the anthropological literature is that continuous tooth eruption occurred without the concomitant coronal movement of alveolar bone. This conclusion has significant ramifications for anthropological, epidemiological, and clinical studies which use the CEJ and AC as reference points when measuring periodontal attachment loss (periodontitis).

  11. SOLAR MULTIPLE ERUPTIONS FROM A CONFINED MAGNETIC STRUCTURE

    SciTech Connect

    Lee, Jeongwoo; Chae, Jongchul; Liu, Chang

    2016-09-20

    How eruption can recur from a confined magnetic structure is discussed based on the Solar Dynamics Observatory observations of the NOAA active region 11444, which produced three eruptions within 1.5 hr on 2012 March 27. The active region (AR) had the positive-polarity magnetic fields in the center surrounded by the negative-polarity fields around. Since such a distribution of magnetic polarity tends to form a dome-like magnetic fan structure confined over the AR, the multiple eruptions were puzzling. Our investigation reveals that this event exhibits several properties distinct from other eruptions associated with magnetic fan structures: (i) a long filament encirclingmore » the AR was present before the eruptions; (ii) expansion of the open–closed boundary (OCB) of the field lines after each eruption was suggestive of the growing fan-dome structure, and (iii) the ribbons inside the closed magnetic polarity inversion line evolved in response to the expanding OCB. It thus appears that in spite of multiple eruptions the fan-dome structure remained undamaged, and the closing back field lines after each eruption rather reinforced the fan-dome structure. We argue that the multiple eruptions could occur in this AR in spite of its confined magnetic structure because the filament encircling the AR was adequate for slipping through the magnetic separatrix to minimize the damage to its overlying fan-dome structure. The result of this study provides a new insight into the productivity of eruptions from a confined magnetic structure.« less

  12. Models of volcanic eruption hazards

    SciTech Connect

    Wohletz, K.H.

    1992-01-01

    Volcanic eruptions pose an ever present but poorly constrained hazard to life and property for geothermal installations in volcanic areas. Because eruptions occur sporadically and may limit field access, quantitative and systematic field studies of eruptions are difficult to complete. Circumventing this difficulty, laboratory models and numerical simulations are pivotal in building our understanding of eruptions. For example, the results of fuel-coolant interaction experiments show that magma-water interaction controls many eruption styles. Applying these results, increasing numbers of field studies now document and interpret the role of external water eruptions. Similarly, numerical simulations solve the fundamental physics of high-speed fluid flow and give quantitative predictions that elucidate the complexities of pyroclastic flows and surges. A primary goal of these models is to guide geologists in searching for critical field relationships and making their interpretations. Coupled with field work, modeling is beginning to allow more quantitative and predictive volcanic hazard assessments.

  13. Predicting Major Solar Eruptions

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-05-01

    Coronal mass ejections (CMEs) and solar flares are two examples of major explosions from the surface of the Sun but theyre not the same thing, and they dont have to happen at the same time. A recent study examines whether we can predict which solar flares will be closely followed by larger-scale CMEs.Image of a solar flare from May 2013, as captured by NASAs Solar Dynamics Observatory. [NASA/SDO]Flares as a Precursor?A solar flare is a localized burst of energy and X-rays, whereas a CME is an enormous cloud of magnetic flux and plasma released from the Sun. We know that some magnetic activity on the surface of the Sun triggers both a flare and a CME, whereas other activity only triggers a confined flare with no CME.But what makes the difference? Understanding this can help us learn about the underlying physical drivers of flares and CMEs. It also might help us to better predict when a CME which can pose a risk to astronauts, disrupt radio transmissions, and cause damage to satellites might occur.In a recent study, Monica Bobra and Stathis Ilonidis (Stanford University) attempt to improve our ability to make these predictions by using a machine-learning algorithm.Classification by ComputerUsing a combination of 6 or more features results in a much better predictive success (measured by the True Skill Statistic; higher positive value = better prediction) for whether a flare will be accompanied by a CME. [Bobra Ilonidis 2016]Bobra and Ilonidis used magnetic-field data from an instrument on the Solar Dynamics Observatory to build a catalog of solar flares, 56 of which were accompanied by a CME and 364 of which were not. The catalog includes information about 18 different features associated with the photospheric magnetic field of each flaring active region (for example, the mean gradient of the horizontal magnetic field).The authors apply a machine-learning algorithm known as a binary classifier to this catalog. This algorithm tries to predict, given a set of features

  14. Taking Care of Your Teeth

    MedlinePlus

    ... dental records), a dental examination, and a professional cleaning. The dentist will examine your teeth, gums, and ... by swollen tissue), or impacted wisdom teeth. Professional cleaning is usually performed by a dental hygienist, a ...

  15. Taking Care of Your Teeth

    MedlinePlus

    ... re choosing a toothpaste, make sure it contains fluoride . Fluoride makes your teeth strong and protects them from ... this topic for: Kids Movie: Teeth How Does Fluoride Work? Bad Breath Going to the Dentist Going ...

  16. The effects of local trauma to the enamel-related periodontal tissues in the eruption of the rat incisor.

    PubMed

    Merzel, J J; Novaes, P P; Furlan, S S

    2000-04-01

    The periodontal tissues related to enamel (PTE) of the rat incisor comprise a connective tissue derived from the dental follicle and the enamel organ with its successive stages of development. Localized damage to these tissues in rat lower incisors was done surgically in three ways: with an endodontic file introduced into the labial periodontal space through either (i) its basal or (ii) its incisal extremities, or (iii) by the partial removal of the mandibular lower border, at the level of the molar teeth, together with the introduction of an endodontic file into the incisal part of that space. The lesions in the molar region of the PTE produced first a variable period of retarded eruption, and, depending upon their extent or degree were followed by a cessation of the eruptive movement and, in the majority of the operated teeth, a recovery of the normal eruption rate before the end of the experiment (17 weeks after surgery). Access to the PTE through the basal portion of the socket was erratic, but when the tissues were damaged produced similar effects. Effects on eruption of lesions produced through the alveolar crest were minimal or even absent. Localized injury to the periodontal ligament of either lower or upper incisors did not produce similar effects on tooth eruption. The dental follicle and the enamel organ of teeth of limited growth when their crown is completed are similar to the PTE in the molar region of continuously growing rodent incisors. In teeth of limited growth these tissues play an essential part in the intraosseous stage of eruption. The results here suggest that the PTE may also have a role in the supraosseous stage of eruption, which is continuous in teeth such as rat incisors due to the presence of a continuously functioning odontogenic organ.

  17. Prophylaxis of impacted teeth using MRI and focal ultra-sound ablation?… a feasible hypothesis.

    PubMed

    Touyz, Louis Z G; Dent, M

    2012-09-01

    Teeth start as bi-layered epithelial soft tissue follicles within bony jaws. Follicles grow into teeth and erupt. Early third molar follicles are detectable 8-9 years (±9 months). Intra-oral dental arches of jaws have finite space accommodating formed crowns. The last teeth to erupt are third molars. When the space needed by all the teeth exceeds the total arch space available, wisdom teeth may become impacted in bone. Lower impactions are more prevalent due to the mandible shape, and impaction associated pathologies with erupting partially or totally impacted teeth are common. Impacted third molars are universally prevalent from 17 to 23 years. Third molar impactions are sources of infection, pain, cyst formation and contribute to malocclusions and other pathologies. Surgical removal of third molars is traumatic, invasive and painful and may produce complicating morbidities. Magnetic resonance imaging (MRI) is used to locate lesions with clear definition and accurate targeting, both in soft and hard tissue organs. Focused ultrasound (FUS) is used to ablate hard and soft tissue structures and stops growth of targeted pathologies. For example, FUS is used to ablate CNS brain tumours, cell causing Parkinson's disease, prostatic growths and thrombolysis in strokes. Modern imaging techniques, like MRI, can accurately locate third molar follicles at age 9, before wisdom teeth form and grow. MRI in combination with FUS could be used to ablate follicles of third molars, stop tooth growth (both crown and root) and so avoid later impactions. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. Relationship of deciduous teeth emergence with physical growth.

    PubMed

    Soliman, Nadia L; El-Zainy, Medhat A; Hassan, Rania Mossad; Aly, Riham Mohamed

    2012-01-01

    Tooth eruption, recognized as an aspect of human growth and development, could possibly be influenced by a number of factors. It may reflect the general body development. The aim of the present research is to investigate the relationship of deciduous teeth emergence with physical growth (weight/height indices). A study was conducted among a sample of 1132 Egyptian infants whose ages range from 4 to 36 months. The sample was collected from some randomly selected health centers affiliated to the ministry of health where various socioeconomic strata from different geographic localities were recruited. The children visit there regularly for vaccination at definite ages. Weight and height were evaluated as factors that might have influence on the time of deciduous teeth emergence. The results showed a certain degree of correlation between the number of deciduous teeth emerged and the studied anthropometric measurements which differed by sex and age. All anthropometric parameters showed relationship with the number of teeth at different levels. Although weight showed influence on the number of teeth emerged, it was less significant than height.

  19. Will Teide erupt again?

    NASA Astrophysics Data System (ADS)

    Marti, Joan; Geyer, Adelina

    2016-04-01

    The quantification of hazard in volcanic systems characterised by long repose period is difficult because the lack of knowledge of the past volcanic history and also because in many cases volcanism is not perceived as a potential problem, being only regarded as an attraction for tourism or a source of economic benefit, thus hiding the need to conduct hazard assessment. Teide, in the island of Tenerife (Canary Islands), is not an exception to this general rule and, despite being one of the largest composite volcanoes in the World, it is generally considered as a non-active volcano by population, visitors and even by some scientists. However, geological and geophysical evidence, including a large diversity of monitoring signals recorded during last decades, as well as a simple comparison with similar volcanoes that have erupted in recent times after hundreds or even thousands of years of quiescence, recommend to consider Teide as an active volcano and to take the necessary precaution in an island with nearly one million of permanent inhabitants and nearly 5 millions of visitors per year. What is the potential of Teide to erupt again? is the question that relies behind the fact of considering it as active, and that needs to be answered first. Based on the current volcanological, petrological and geophysical knowledge We propose a conceptual model on the magma recharge mechanisms, structure of the plumbing system, and eruption triggers and dynamics of Teide volcano that helps to understand its behaviour and to anticipate future activity. Ramón y Cajal contract (RYC-2012-11024)

  20. Conventional wisdom and the surgical exposure of impacted teeth.

    PubMed

    Becker, A; Casap, N; Chaushu, S

    2009-05-01

    To provide evidence against the notion that direct contact between the crown of an impacted tooth and alveolar bone is an impediment to orthodontically assisted eruption of teeth. The Department of Orthodontics at the Hebrew University-Hadassah School of Dental Medicine, in Jerusalem, Israel, and the private practices of the authors. Patients reported were those affected by impacted teeth, including individuals who were normal healthy patients, with and without resorption of the adjacent incisor roots, as well as individuals suffering from Cleidocranial dysplasia and increased bone density, and individuals with autogenous and synthetic bone grafts. A closed eruption surgical technique was used in which only a small window was opened into the dental follicle of the impacted tooth, leaving a maximum amount of bone covering much of the crown surface. Orthodontic extrusion forces were then applied. For all teeth, enamel-to-bone contact did not prevent a rapid response to the extrusive forces. Radical removal of bone during the exposure of an impacted tooth is unnecessary and potentially may be harmful in terms of the periodontal prognosis of an otherwise successfully treated outcome.

  1. Estimating the Likelihood of Volcanic Eruptions with Incomplete Eruption Records

    NASA Astrophysics Data System (ADS)

    Wang, T.; Bebbington, M. S.

    2015-12-01

    Despite ongoing efforts worldwide to compile different databases for volcanic eruptions, eruption records, particularly those of earlier time periods, are pervasively incomplete, a problem that is exacerbated when dealing with catalogs derived from geologic records. When using statistical models to analyze this type of records, missing data can strongly influence the parameter estimates, which are usually obtained by maximizing the log likelihood function, and hence affect the future hazard estimate. This work explores a hidden Markov model framework to handle missing data in volcanic eruption records. This framework will enable us to estimate the completeness level of the records, and offers a means of determining where in the record the missing observations are likely to be found. We apply these methods to different volcanic eruption records with the aim to estimate the completeness of the records over time and to obtain more robust estimates of the likelihood of future eruptions.

  2. Data-driven magnetohydrodynamic modelling of a flux-emerging active region leading to solar eruption

    PubMed Central

    Jiang, Chaowei; Wu, S. T.; Feng, Xuesheng; Hu, Qiang

    2016-01-01

    Solar eruptions are well-recognized as major drivers of space weather but what causes them remains an open question. Here we show how an eruption is initiated in a non-potential magnetic flux-emerging region using magnetohydrodynamic modelling driven directly by solar magnetograms. Our model simulates the coronal magnetic field following a long-duration quasi-static evolution to its fast eruption. The field morphology resembles a set of extreme ultraviolet images for the whole process. Study of the magnetic field suggests that in this event, the key transition from the pre-eruptive to eruptive state is due to the establishment of a positive feedback between the upward expansion of internal stressed magnetic arcades of new emergence and an external magnetic reconnection which triggers the eruption. Such a nearly realistic simulation of a solar eruption from origin to onset can provide important insight into its cause, and also has the potential for improving space weather modelling. PMID:27181846

  3. Data-driven magnetohydrodynamic modelling of a flux-emerging active region leading to solar eruption.

    PubMed

    Jiang, Chaowei; Wu, S T; Feng, Xuesheng; Hu, Qiang

    2016-05-16

    Solar eruptions are well-recognized as major drivers of space weather but what causes them remains an open question. Here we show how an eruption is initiated in a non-potential magnetic flux-emerging region using magnetohydrodynamic modelling driven directly by solar magnetograms. Our model simulates the coronal magnetic field following a long-duration quasi-static evolution to its fast eruption. The field morphology resembles a set of extreme ultraviolet images for the whole process. Study of the magnetic field suggests that in this event, the key transition from the pre-eruptive to eruptive state is due to the establishment of a positive feedback between the upward expansion of internal stressed magnetic arcades of new emergence and an external magnetic reconnection which triggers the eruption. Such a nearly realistic simulation of a solar eruption from origin to onset can provide important insight into its cause, and also has the potential for improving space weather modelling.

  4. Snaking Filament Eruption [video

    NASA Image and Video Library

    2014-11-14

    A filament (which at one point had an eerie similarity to a snake) broke away from the sun and out into space (Nov. 1, 2014). The video covers just over three hours of activity. This kind of eruptive event is called a Hyder flare. These are filaments (elongated clouds of gases above the sun's surface) that erupt and cause a brightening at the sun's surface, although no active regions are in that area. It did thrust out a cloud of particles but not towards Earth. The images were taken in the 304 Angstrom wavelength of extreme UV light. Credit: NASA/Solar Dynamics Observatory NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

  5. Snaking Filament Eruption

    NASA Image and Video Library

    2014-11-14

    A filament (which at one point had an eerie similarity to a snake) broke away from the sun and out into space (Nov. 1, 2014). The video covers just over three hours of activity. This kind of eruptive event is called a Hyder flare. These are filaments (elongated clouds of gases above the sun's surface) that erupt and cause a brightening at the sun's surface, although no active regions are in that area. It did thrust out a cloud of particles but not towards Earth. The images were taken in the 304 Angstrom wavelength of extreme UV light. Credit: NASA/Solar Dynamics Observatory NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

  6. Volcanic Eruptions on Io

    NASA Technical Reports Server (NTRS)

    1979-01-01

    This dramatic view of Jupiter's satellite Io shows two simultaneously occurring volcanic eruptions. One can be seen on the limb, (at lower right) in which ash clouds are rising more than 150 miles (260 kilometers) above the satellite's surface. The second can be seen on the terminator (shadow between day and night) where the volcanic cloud is catching the rays of the rising sun. The dark hemisphere of Io is made visible by light reflected from Jupiter. Seen in Io's night sky, Jupiter looms almost 40 times larger and 200 times brighter than our own full Moon. This photo was taken by Voyager 1 on March 8, 1979, looking back 2.6 million miles (4.5 million kilometers) at Io, three days after its historic encounter. This is the same image in which Linda A. Morabito, a JPL engineer, discovered the first extraterrestrial volcanic eruption (the bright curved volcanic cloud on the limb). Jet Propulsion Laboratory manages and controls the Voyager project for NASA's Office of Space Science.

  7. Nyamuragira Volcano Erupts

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Nyamuragira volcano erupted on July 26, 2002, spewing lava high into the air along with a large plume of steam, ash, and sulfur dioxide. The 3,053-meter (10,013-foot) volcano is located in eastern Congo, very near that country's border with Rwanda. Nyamuragira is the smaller, more violent sibling of Nyiragongo volcano, which devastated the town of Goma with its massive eruption in January 2002. Nyamuragira is situated just 40 km (24 miles) northeast of Goma. This pair of images was acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS), flying aboard NASA's Terra satellite, on July 26. The image on the left shows the scene in true color. The small purple box in the upper righthand corner marks the location of Nyamuragira's hot summit. The false-color image on the right shows the plume from the volcano streaming southwestward. This image was made using MODIS' channels sensitive at wavelengths from 8.5 to 11 microns. Red pixels indicate high concentrations of sulphur dioxide. Image courtesy Liam Gumley, Space Science and Engineering Center, University of Wisconsin-Madison

  8. The physics of large eruptions

    NASA Astrophysics Data System (ADS)

    Gudmundsson, Agust

    2015-04-01

    Based on eruptive volumes, eruptions can be classified as follows: small if the volumes are from less than 0.001 km3 to 0.1 km3, moderate if the volumes are from 0.1 to 10 km3, and large if the volumes are from 10 km3 to 1000 km3 or larger. The largest known explosive and effusive eruptions have eruptive volumes of 4000-5000 km3. The physics of small to moderate eruptions is reasonably well understood. For a typical mafic magma chamber in a crust that behaves as elastic, about 0.1% of the magma leaves the chamber (erupted and injected as a dyke) during rupture and eruption. Similarly, for a typical felsic magma chamber, the eruptive/injected volume during rupture and eruption is about 4%. To provide small to moderate eruptions, chamber volumes of the order of several tens to several hundred cubic kilometres would be needed. Shallow crustal chambers of these sizes are common, and deep-crustal and upper-mantle reservoirs of thousands of cubic kilometres exist. Thus, elastic and poro-elastic chambers of typical volumes can account for small to moderate eruptive volumes. When the eruptions become large, with volumes of tens or hundreds of cubic kilometres or more, an ordinary poro-elastic mechanism can no longer explain the eruptive volumes. The required sizes of the magma chambers and reservoirs to explain such volumes are simply too large to be plausible. Here I propose that the mechanics of large eruptions is fundamentally different from that of small to moderate eruptions. More specifically, I suggest that all large eruptions derive their magmas from chambers and reservoirs whose total cavity-volumes are mechanically reduced very much during the eruption. There are two mechanisms by which chamber/reservoir cavity-volumes can be reduced rapidly so as to squeeze out much of, or all, their magmas. One is piston-like caldera collapse. The other is graben subsidence. During large slip on the ring-faults/graben-faults the associated chamber/reservoir shrinks in volume

  9. [Application of a modified stage classification in evaluating wisdom tooth eruption in a German population].

    PubMed

    Olze, Andreas; Peschke, Corinna; Schulz, Ronald; Schmeling, Andreas

    2012-01-01

    The evaluation of the eruption status of the wisdom teeth constitutes a significant component of the spectrum of dental methods available for purposes of forensic age diagnostics. In the present study, the status of wisdom tooth eruption was identified in 606 conventionally created orthopantomograms of 515 female and 91 male Germans, divided by sex and tooth, using a modified classification comprising four stages. Instead of the original stage C (gingival eruption) which cannot always be reliably identified on X-ray images of suboptimal quality, stage C of the modified classification was considered reached when the erupting wisdom tooth had reached at least half the length of the crown of the adjacent second molar, without however having yet reached the occlusal plane. The new stage classification is especially recommended for age estimation based on X-ray images in which a conclusive delimitation of the gingiva is not possible.

  10. Case report: Unclassified syndrome involving dental enamel, dentine and lack of tooth eruption.

    PubMed

    Jensen, J L; Ambjornsen, E; Haanaes, H R; Storhaug, K

    2009-12-01

    Regional odontodysplasia, also described as ghost teeth, has been described on a number of occasions, in some cases generalized odontodysplasia affecting both the primary and the permanent dentition. However, generalised odontodysplasia is a very rare finding, involving large pulps and short roots of the whole dentition and in the cases previously reported the teeth finally erupt. In the case reported on herein this has not happened. A female patient, now aged 22-years-old, cared for in the TAKO-centre (Oslo) since she was 5 years old, presented with a continuing problem of absence of permanent teeth due to total lack of eruption. All her permanent teeth were either retained intra-alveolar or had been extracted following previous periods of pain and infections. There was no enamel on any of the permanent teeth and the dentine was softer than normal. In addition, there appeared to be very little potential for eruption. Hence, tooth development was affected in all aspects. Her skeletal height was much shorter than expected taking her tall parents into consideration. After all possible assessments, no specific diagnosis for the condition of this young woman has been determined. Before the present series of dental care the patient was wearing full dentures in both jaws. In the autumn of 2007, implants were placed in her maxilla and an implant supported fixed prosthesis in porcelain was installed the following spring. Similarly, implants were placed in her mandible, partly in retained teeth, in the autumn of 2008, and an implant supported fixed prosthesis was inserted during the spring of 2009. after prosthetic treatment a dental hygienist has seen the patient regularly. No problems or signs of infections have occurred to date. This case report concerns a rare and apparently un-named syndrome affecting both primary and permanent teeth. This paper has been written with an aim of gathering the views as to the aetiology of her problem, hopefully finally to provide a

  11. Predicting Solar Filament Eruptions with HEK Filament Metadata

    NASA Astrophysics Data System (ADS)

    Aggarwal, A.; Reeves, K.; Schanche, N.

    2015-12-01

    Solar filaments are cool, dark channels of partially-ionized plasma that lie above the chromosphere. Their structure follows the neutral line between local regions of opposite magnetic polarity. Previous research (e.g. Schmieder et al. 2013) has shown a positive correlation (80%) between the occurrence of filament eruptions and coronal mass ejections (CME's). If certain filament properties, such as length, chirality, and tilt, indicate a tendency towards filament eruptions, one may be able to further predict an oncoming CME. Towards this end, we present a novel algorithm based on spatiotemporal analysis that systematically correlates filament eruptions documented in the Heliophysics Event Knowledgebase (HEK) with HEK filaments that have been grouped together using a tracking algorithm developed at Georgia State University (e.g. Kempton et al. 2014). We also find filament tracks that are not correlated with eruptions to form a null data set in a similar fashion. Finally, we compare the metadata from erupting and non-erupting filament tracks to discover which filament properties may present signs of an eruption onset. Through statistical methods such as the two-sample Kolmogorov-Smirnov test and Random Forest Classifier, we find that a filament that is increasing in length or changing in tilt with respect to the equator may be a useful gauge to predict a filament eruption. However, the average values of length and tilt for both datasets follow similar distributions, leading us to conclude that these parameters do not indicate an eruption event. This work is supported by the NSF-REU solar physics program at SAO, grant number AGS-1263241, and NSF DIBBS grant number ACI-1443061.

  12. [Bullous drug eruption with Nigella sativa oil].

    PubMed

    Gelot, P; Bara-Passot, C; Gimenez-Arnau, E; Beneton, N; Maillard, H; Celerier, P

    2012-04-01

    Nigella sativa is classically used for its various therapeutic properties, particularly in the field of allergic diseases. We report a case of bullous eruption following application of Nigella sativa oil to the skin, possibly involving an associated systemic mechanism linked to ingestion of the oil. A 53-year-old woman was hospitalized for febrile rash consisting of erythematous plaques with vesicles and bullous lesions. She had Nigella sativa oil applied to her skin and ingested it for two weeks. Cutaneous histopathology revealed sub-epidermal detachment and necrosis of the epidermal surface consistent with toxic epidermal necrolysis. The lesions healed slowly, but depigmented macules persisted three months later. Patch tests for Nigella sativa oil were strongly positive. Erythema multiforme due to contact with Nigella sativa oil was initially diagnosed on the basis of lesions on skin where the oil was applied, as well as on cutaneous histopathology and positive patch tests. However, a systemic reaction such as toxic epidermal necrolysis could not be ruled out since the patient had also ingested the oil. The most likely diagnosis was thus systemic and contact bullous drug eruption. The discovery of new therapeutic properties of Nigella sativa in other clinical domains underscores the need for particular vigilance regarding future use of this substance on account of the risk of severe drug eruptions. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  13. Formation and dynamics of a solar eruptive flux tube.

    PubMed

    Inoue, Satoshi; Kusano, Kanya; Büchner, Jörg; Skála, Jan

    2018-01-12

    Solar eruptions are well-known drivers of extreme space weather, which can greatly disturb the Earth's magnetosphere and ionosphere. The triggering process and initial dynamics of these eruptions are still an area of intense study. Here we perform a magnetohydrodynamic simulation taking into account the observed photospheric magnetic field to reveal the dynamics of a solar eruption in a real magnetic environment. In our simulation, we confirmed that tether-cutting reconnection occurring locally above the polarity inversion line creates a twisted flux tube, which is lifted into a toroidal unstable area where it loses equilibrium, destroying the force-free state, and driving the eruption. Consequently, a more highly twisted flux tube is built up during this initial phase, which can be further accelerated even when it returns to a stable area. We suggest that a nonlinear positive feedback process between the flux tube evolution and reconnection is the key to ensure this extra acceleration.

  14. A comparison of the use of cone-beam computed tomography and panoramic radiography in the assessment of pre-eruptive intracoronal resorption.

    PubMed

    Demirtas, Omer; Dane, Asım; Yildirim, Eren

    2016-11-01

    This study aimed to investigate the prevalence of pre-eruptive intracoronal resorption (PIR) using cone beam computed tomography (CBCT) and panoramic radiography and to compare the findings of these imaging techniques. This retrospective study consisted of 733 patients who had at least one unerupted tooth and had undergoneimaging with both three-dimensional (3D) CBCT and two-dimensional (2D) panoramic radiography. In all the images, the number of teeth with intracoronal resorption, affected tooth type and number, and size and location of the PIR defects were recorded. The McNemar test was used to compare the prevalence of PIR in the CBCT and panoramic images. Fewer PIR defects were detected in the panoramic images (3.1% of the patients) than in the CBCT images (9.5% of the patients) (p< .001). According to the CBCT images, the distribution of PIR defects was as follows: third molars (59.5%), canine teeth (11.4%), second molars and premolars (7.6% for both), supernumerary teeth (5.1%), second molars (3.8%), central incisors (2.5%), and first premolar and primary second molar teeth (1.5% for both). According to the scoring classification system for PIR defects, PIR 1 defects were the most common (65.8%), followed by PIR 3 (24.1%) and PIR 2 (10.1%). Of these defects, 69.6% were located in the central aspect of the crown. Ectopically positioned teeth showing intracoronal resorption accounted for 51.9% of the cases of PIR. CBCT detected more cases of PIR than panoramic radiography. The mandibular third permanent molar was the most commonly affected tooth.

  15. Analysis of colored teeth from Precolumbian Tlatelolco: postmortem transformation or intravitam processes?

    PubMed

    Mansilla, J; Solis, C; Chávez-Lomeli, M E; Gama, J E

    2003-01-01

    The etiological basis of the abnormal coloration of archaeological teeth has been an unsolved question for a long time. Differences in the appearance of some archaeological teeth from Precolumbian adult and infant skeletons, detected by external optical inspection, led us to study this problem. A blue stain is visible in a few of the deciduous erupted teeth, and a brown color in various unerupted teeth in the collection, while brown spots appear on some permanent teeth. Several processes or factors that may occur during one's life, others around the time of death, and still others resulting from postmortem alterations have been reported as potential causes of abnormal tooth coloration.A sample of 35 colored teeth and two soil layers taken from Tlatelolco were analyzed by particle-induced X-ray emission (PIXE) as well as selective dissolution techniques. Concentrations of total and extractable elements in enamel and soil layers (Cg1-Cg2) were obtained. This paper describes the occurrence and implications of a substantial secondary concentration of Zinc (Zn), manganese (Mn), strontium (Sr), and iron (Fe) in the deciduous erupted and nonerupted teeth as compared to that in the adult teeth. Our interpretation is that, in this archaeological context, the brown spots and blue stains on the teeth are due to differences in tooth enamel porosity and to a postmortem biogeochemical process. The alterations involve cumulization and diagenesis of iron, manganese, and organic matter solutions that were eluviated from the soil and are not the result of antemortem or perimortem conditions such as trauma or disease. Copyright 2003 Wiley-Liss, Inc.

  16. Solar Eruptive Events

    NASA Technical Reports Server (NTRS)

    Holman, Gordon D.

    2012-01-01

    It s long been known that the Sun plays host to the most energetic explosions in the solar system. But key insights into the forms that energy takes have only recently become available. Solar flares have been phenomena of both academic and practical interest since their discovery in 1859. From the academic point of view, they are the nearest events for studying the explosive release of energy in astrophysical magnetized plasmas. From the practical point of view, they disrupt communication channels on Earth, from telegraph communications in 1859 to radio and television signals today. Flares also wreak havoc on the electrical power grid, satellite operations, and GPS signals, and energetic charged particles and radiation are dangerous to passengers on high-altitude polar flights and to astronauts. Flares are not the only explosive phenomena on the Sun. More difficult to observe but equally energetic are the large coronal mass ejections (CMEs), the ejection of up to ten billion tons of magnetized plasma into the solar wind at speeds that can exceed 1000 km/s. CMEs are primarily observed from the side, with coronagraphs that block out the bright disk of the Sun and lower solar atmosphere so that light scattered from the ejected mass can be seen. Major geomagnetic storms are now known to arise from the interaction of CMEs with Earth's magnetosphere. Solar flares are observed without CMEs, and CMEs are observed without flares. The two phenomena often occur together, however, and almost always do in the case of large flares and fast CMEs. The term solar eruptive event refers to the combination of a flare and a CME. Solar eruptive events generate a lot of heat: They can heat plasma to temperatures as high at 50 million Kelvin, producing radiation across the electromagnetic spectrum. But that s not all. A fascinating aspect of solar eruptive events is the acceleration of electrons and ions to suprathermal often relativistic energies. The accelerated particles are primarily

  17. Eruption at Bardarbunga, Iceland

    NASA Image and Video Library

    2015-01-27

    The main caldera of Bardarbunga volcano is tucked beneath Iceland’s largest glacier, Vatnajökull. Beginning in August, 2014, red-hot basaltic lava originating from Bardarbunga has been pouring from fissures just north of Vatnajökull, creating the massive Holuhraun lava field. As of January 6, 2015, the Holuhraun lava field had spread across more than 84 square kilometers (32 square miles), making it larger than the island of Manhattan. Holuhraun is Iceland’s largest basaltic lava flow since the Laki eruption in 1783–84, an event that killed 20 percent of the island’s population. Scientists from the University of Iceland’s Institute of Earth Sciences have estimated the thickness of the lava field based on data from surveillance flights. On average, the eastern part was about 10 meters (33 feet) thick, the center was 12 meters, and the western part was 14 meters. Their preliminary analysis put the volume of lava at 1.1 cubic kilometers, enough for the eruption to be considered a flood basalt. While Holuhraun continues to spew copious amounts of lava and sulfur dioxide, some observations suggest the eruption may be slowing down. As Edinburgh University volcanologist John Stevenson noted on his blog, Icelandic scientists have shown that the sinking (subsidence) of the caldera has declined from 80 centimeters (31 inches) to 25 centimeters per day—a sign that less magma is moving toward the surface. In addition, magnitude 5 or higher earthquakes that used to occur daily are now happening about once a week. Meanwhile, satellite observations of heat flux show a decline from more than 20 gigawatts in early September to fewer than 5 gigawatts by the end of November. As reported by Volcano Discovery, one bold scientist has even suggested that it is reasonable to forecast that the eruption may be over by March, 2015. The Moderate Resolution Imaging Spectrometer (MODIS) aboard NASA’s Aqua satellite flew over Iceland on January 18, 2015 and captured a false

  18. Supernumerary teeth and dental management in Sotos syndrome.

    PubMed

    Raitz, R; Laragnoit, A

    2009-01-01

    Sotos syndrome is a genetic disorder characterized by early and excessive growth, acromegalic features, mental retardation, advanced bone age, and a distinctive facial appearance. The oral findings commonly seen with Sotos syndrome include: premature eruption of teeth; high, arched palate; pointed chin; and, more rarely, prognathism. The purpose of this case report was to review the diagnostic characteristics of Sotos syndrome, highlighting an interesting case involving six supernumerary teeth, and emphasize the importance of a multiprofessional dental intervention in combination with active family participation. Due to its rarity, many of the particularities of Sotos syndrome remain unknown. Close family and professional supervision are required to ensure that Sotos syndrome patients receive appropriate dental treatment.

  19. The ability of orthodontists and oral/maxillofacial surgeons to predict eruption of lower third molar.

    PubMed

    Bastos, Aline do Carmo; de Oliveira, Joelma Bezerra; Mello, Karina Flexa Ribeiro; Leão, Patrícia Botelho; Artese, Flavia; Normando, David

    2016-12-01

    The aim of this study was to evaluate the ability of oral/maxillofacial surgeons (OMFSs) and orthodontists to predict third molar eruption by examining a simple panoramic radiograph in cases where full spontaneous eruption occurred. Panoramic radiographs of 17 patients, 13-16 years of age, were obtained just after orthodontic treatment (T1), when the third molars were intraosseous. The radiographs at T1 were presented to 28 OMFSs and 28 orthodontists-who were asked to give a prognosis for the lower third molars on both sides (n = 34). The full spontaneous eruption of all third molars was clinically observed when patients were older than 18 years (T2). These teeth were clinically asymptomatic at T1 and T2. OMFSs decided by extractions in 49.6 % of cases while orthodontists in 37.8 % (p < 0.001), when the radiographs were examined at T1. Agreement between OMFSs and orthodontists was excellent (Kappa = 0.76, p < 0.0001), as well as intragroup agreement for both OMFSs (Kappa = 0.83) and orthodontists (Kappa = 0.96). Despite a remarkable agreement for third molar prognosis, orthodontists and OMFSs were unable to predict lower third molar eruption by examining a simple panoramic radiograph. Both indicated extractions of a considerable number of spontaneously erupted asymptomatic teeth.

  20. Intrusion triggering of the 2010 Eyjafjallajökull explosive eruption.

    PubMed

    Sigmundsson, Freysteinn; Hreinsdóttir, Sigrún; Hooper, Andrew; Arnadóttir, Thóra; Pedersen, Rikke; Roberts, Matthew J; Oskarsson, Níels; Auriac, Amandine; Decriem, Judicael; Einarsson, Páll; Geirsson, Halldór; Hensch, Martin; Ofeigsson, Benedikt G; Sturkell, Erik; Sveinbjörnsson, Hjörleifur; Feigl, Kurt L

    2010-11-18

    Gradual inflation of magma chambers often precedes eruptions at highly active volcanoes. During such eruptions, rapid deflation occurs as magma flows out and pressure is reduced. Less is known about the deformation style at moderately active volcanoes, such as Eyjafjallajökull, Iceland, where an explosive summit eruption of trachyandesite beginning on 14 April 2010 caused exceptional disruption to air traffic, closing airspace over much of Europe for days. This eruption was preceded by an effusive flank eruption of basalt from 20 March to 12 April 2010. The 2010 eruptions are the culmination of 18 years of intermittent volcanic unrest. Here we show that deformation associated with the eruptions was unusual because it did not relate to pressure changes within a single magma chamber. Deformation was rapid before the first eruption (>5 mm per day after 4 March), but negligible during it. Lack of distinct co-eruptive deflation indicates that the net volume of magma drained from shallow depth during this eruption was small; rather, magma flowed from considerable depth. Before the eruption, a ∼0.05 km(3) magmatic intrusion grew over a period of three months, in a temporally and spatially complex manner, as revealed by GPS (Global Positioning System) geodetic measurements and interferometric analysis of satellite radar images. The second eruption occurred within the ice-capped caldera of the volcano, with explosivity amplified by magma-ice interaction. Gradual contraction of a source, distinct from the pre-eruptive inflation sources, is evident from geodetic data. Eyjafjallajökull's behaviour can be attributed to its off-rift setting with a 'cold' subsurface structure and limited magma at shallow depth, as may be typical for moderately active volcanoes. Clear signs of volcanic unrest signals over years to weeks may indicate reawakening of such volcanoes, whereas immediate short-term eruption precursors may be subtle and difficult to detect.

  1. Aurorae and Volcanic Eruptions

    NASA Astrophysics Data System (ADS)

    2001-06-01

    1 month, and a very high temperature, more than 1000 K (700 °C). However, the Tvashtar outburst is quite anomalous and has lasted more than one year. The temperature has been estimated at about 1000-1300 K (700-1000 °C); this range is typical for silicate-based volcanism observed on the Earth. The Galileo spacecraft observed the onset of this eruption, and twice again this year. Monitoring of this event by means of ground-based telescopes, as here with ISAAC at the VLT or by the ADONIS Adaptive Optics system on the ESO 3.6-m telescope at La Silla, gives the astronomers a most welcome opportunity to follow more closely the temperature evolution of the eruption and hence provides excellent support to the space observations. The forthcoming arrival on Paranal of NAOS (the adaptive optics system for the VLT) and CONICA (the connected IR camera equipped with an Aladdin detector) will lead to a significant improvement of the achievable image quality. It will be employed for a large variety of astronomical programmes and will, among others, allow the detection and frequent monitoring of a large number of hot spots on the surface of Io . Note [1]: ISAAC registers (infrared) electromagnetic radiation at wavelengths between approx. 1.0 and 5.0 µm which we sense as heat. The human eye registers electromagnetic radiation (light) at shorter wavelengths, from about 0.4 to 0.7 µm. Technical information about the photos PR Photos 21a-d/01 are based on on-target exposures lasting a total of 30 sec (L-band), 44 sec (4.07 µm), 58 sec (3.28 µm) and 58 sec (3.21 µm), respectively. The real observing time is twice as much, with half of the time spent in the off-target chop position. The fields shown measure 72 x 72 arcsec 2 ; 1 pixel = 0.07 arcsec. PR Photo 21e/01 is a colour-coded combination of these four exposures. North is up and East is left. Addendum: About the Jovian aurorae and polar haze Aurorae Borealis and Aurorae Australis ('Northern and Southern Lights') are observed

  2. Numerical and clinical study of the biomechanical behaviour of teeth under orthodontic loading using a headgear appliance.

    PubMed

    Reimann, S; Keilig, L; Jäger, A; Brosh, T; Shpinko, Y; Vardimon, A D; Bourauel, C

    2009-06-01

    It was the purpose of this study to analyse the biomechanical behaviour of posterior teeth under headgear traction with neighbouring teeth in different eruption stages. For doing so a finite element (FE) model of the right part of a human maxilla was developed, based on an almost anatomically correct commercial surface data set of a human maxilla. The FE model included the first molar (M1) with surrounding tooth supporting structures as well as the second (M2) and third molars (M3) in different eruption stages. Calculations were performed, simulating the initial tooth mobility of the M1 under application of headgear forces. The numerical results were compared to a clinical transverse study of orthodontic patients undergoing headgear treatment. From 85 included patients, 41 patients had erupted M2 and/or M3, in the remaining 44 patients these teeth were not yet erupted. The interapproximal gap was measured between M1 and the second premolar (P2) with varying headgear loading and as a function of eruption stage of M2 and M3. Headgear forces on the M1 in the clinical and numerical studies ranged from 1.5 to 7.5 N. After adjustment of the material parameters of the PDL, simulated results deviated less than 5% from the clinical data. A larger deflection of the M1 was registered in treatment situations prior to the eruption of M2 and M3. In absence of M3, about 30% of the applied force was transferred from M1 to M2. The displacements of M1 were twice as large as those of M2. Concluding, the simulated biomechanical behaviour of teeth under headgear loading was in satisfactory congruence with the clinical measurements. Thus the clinical recommendation that the headgear treatment should start in an early stage, prior to eruption of the second and third molars (M2 and M3), is supported by the results of this biomechanical study.

  3. Classical music and the teeth.

    PubMed

    Eramo, Stefano; Di Biase, Mary Jo; De Carolis, Carlo

    2013-01-01

    Teeth and their pathologies are frequent themes in classical music. The teeth have inspired popular songwriters such as Thomas Crecquillon, Carl Loewe, Amilcare Ponchielli & Christian Sinding; as well as composers whose works are still played all over the world, such as Robert Schumann and Jacques Offenbach. This paper examines several selections in which the inspiring theme is the teeth and the pain they can cause, from the suffering of toothache, to the happier occasion of a baby's first tooth.

  4. Microflora around teeth and dental implants

    PubMed Central

    Shahabouee, Mohammad; Rismanchian, Mansour; Yaghini, Jaber; Babashahi, Akram; Badrian, Hamid; Goroohi, Hossein

    2012-01-01

    Background: When an implant is exposed to oral cavity, its surface gets colonized by micro-organisms. The aim of this study is to comparatively assess the microbiological parameters in sulci around the teeth and the crowns supported by dental implants. Materials and Methods: In this prospective, cross-sectional study, 34 partially edentulous patients aged between 40 and 50 years with total 50 anterior maxillary single implants with cemented crowns (depth of sulci <4 mm) and 34 similar teeth in the same jaw of the same patients were included. Excluded were the patients with compromised systemic and periodontal health and smoking habits. None of the patients had used any antimicrobial mouthwashes during at least two weeks before the study. All of the implants (ITI) were at least 6 months in place covered by definitive prostheses. Samples of gingival sulci were taken around teeth with paper cone and transported to Stuart transport medium. Samples were cultured and examined by a dark field microscope and eight laboratory tests were performed to determine the micro-organisms The data were evaluated statistically using Chi-square test (α=0.05). Results: Six anerobic bacteria found in teeth and implants sulci were Gram-positive cocci, Gram-negative cocci, Prevotella, Porphyromonas gingivalis, Bacteroid Fragilis and Fusobacterium. Gram-positive cocci and Gram-negative cocci had maximum and minimum percentage frequency in the two groups, respectively. There were no significant differences between the two groups (P value >0.05). Conclusion: The present study indicated that microflora in implant sulci is similar to the tooth sulci, when the depth of sulci is normal (<4 mm). As a result, implants’ susceptibility to inflammation is the same as teeth. PMID:22623941

  5. Microflora around teeth and dental implants.

    PubMed

    Shahabouee, Mohammad; Rismanchian, Mansour; Yaghini, Jaber; Babashahi, Akram; Badrian, Hamid; Goroohi, Hossein

    2012-03-01

    When an implant is exposed to oral cavity, its surface gets colonized by micro-organisms. The aim of this study is to comparatively assess the microbiological parameters in sulci around the teeth and the crowns supported by dental implants. In this prospective, cross-sectional study, 34 partially edentulous patients aged between 40 and 50 years with total 50 anterior maxillary single implants with cemented crowns (depth of sulci <4 mm) and 34 similar teeth in the same jaw of the same patients were included. Excluded were the patients with compromised systemic and periodontal health and smoking habits. None of the patients had used any antimicrobial mouthwashes during at least two weeks before the study. All of the implants (ITI) were at least 6 months in place covered by definitive prostheses. Samples of gingival sulci were taken around teeth with paper cone and transported to Stuart transport medium. Samples were cultured and examined by a dark field microscope and eight laboratory tests were performed to determine the micro-organisms The data were evaluated statistically using Chi-square test (α=0.05). Six anerobic bacteria found in teeth and implants sulci were Gram-positive cocci, Gram-negative cocci, Prevotella, Porphyromonas gingivalis, Bacteroid Fragilis and Fusobacterium. Gram-positive cocci and Gram-negative cocci had maximum and minimum percentage frequency in the two groups, respectively. There were no significant differences between the two groups (P value >0.05). The present study indicated that microflora in implant sulci is similar to the tooth sulci, when the depth of sulci is normal (<4 mm). As a result, implants' susceptibility to inflammation is the same as teeth.

  6. A Universal Model for Solar Eruptions

    NASA Technical Reports Server (NTRS)

    Wyper, Peter F.; Antiochos, Spiro K.; Devore, C. Richard

    2017-01-01

    Magnetically driven eruptions on the Sun, from stellar-scale coronal mass ejections1 to small-scale coronal X-ray and extreme-ultraviolet jets, have frequently been observed to involve the ejection of the highly stressed magnetic flux of a filament. Theoretically, these two phenomena have been thought to arise through very different mechanisms: coronal mass ejections from an ideal (non-dissipative) process, whereby the energy release does not require a change in the magnetic topology, as in the kink or torus instability; and coronal jets from a resistive process, involving magnetic reconnection. However, it was recently concluded from new observations that all coronal jets are driven by filament ejection, just like large mass ejections. This suggests that the two phenomena have physically identical origin and hence that a single mechanism may be responsible, that is, either mass ejections arise from reconnection, or jets arise from an ideal instability. Here we report simulations of a coronal jet driven by filament ejection, whereby a region of highly sheared magnetic field near the solar surface becomes unstable and erupts. The results show that magnetic reconnection causes the energy release via 'magnetic breakout', a positive feedback mechanism between filament ejection and reconnection. We conclude that if coronal mass ejections and jets are indeed of physically identical origin (although on different spatial scales) then magnetic reconnection (rather than an ideal process) must also underlie mass ejections, and that magnetic breakout is a universal model for solar eruptions.

  7. A universal model for solar eruptions

    NASA Astrophysics Data System (ADS)

    Wyper, Peter F.; Antiochos, Spiro K.; DeVore, C. Richard

    2017-04-01

    Magnetically driven eruptions on the Sun, from stellar-scale coronal mass ejections to small-scale coronal X-ray and extreme-ultraviolet jets, have frequently been observed to involve the ejection of the highly stressed magnetic flux of a filament. Theoretically, these two phenomena have been thought to arise through very different mechanisms: coronal mass ejections from an ideal (non-dissipative) process, whereby the energy release does not require a change in the magnetic topology, as in the kink or torus instability; and coronal jets from a resistive process involving magnetic reconnection. However, it was recently concluded from new observations that all coronal jets are driven by filament ejection, just like large mass ejections. This suggests that the two phenomena have physically identical origin and hence that a single mechanism may be responsible, that is, either mass ejections arise from reconnection, or jets arise from an ideal instability. Here we report simulations of a coronal jet driven by filament ejection, whereby a region of highly sheared magnetic field near the solar surface becomes unstable and erupts. The results show that magnetic reconnection causes the energy release via ‘magnetic breakout’—a positive-feedback mechanism between filament ejection and reconnection. We conclude that if coronal mass ejections and jets are indeed of physically identical origin (although on different spatial scales) then magnetic reconnection (rather than an ideal process) must also underlie mass ejections, and that magnetic breakout is a universal model for solar eruptions.

  8. Nonpigmented fixed drug eruption induced by esomeprazole.

    PubMed

    Morais, Paulo; Baudrier, Teresa; Mota, Alberto; Cunha, Ana Paula; Cadinha, Susana; Barros, Ana Margarida; Azevedo, Filomena

    2010-09-01

    A 56-year-old white woman developed a distinctive skin eruption over her mammary, lumbosacral, and pubic areas 2 weeks after the start of esomeprazole therapy for dyspeptic symptoms. Skin biopsy disclosed a spongiotic dermatitis with predominantly lymphocytic dermal infiltrate. Treatment with a tapering dose of corticosteroid and withdrawal of the suspected drug led to a rapid resolution of the eruption without residual dyschromia. Patch testing with esomeprazole 2% in petrolatum was negative at 48 and 72 hours but became positive on day 6. Oral-controlled provocation test induced the reappearance of the lesions over the mammary areas, confirming the putative involvement of this drug. Therefore, the patient was diagnosed as having a nonpigmented fixed drug eruption associated with esomeprazole. This compound is a proton-pump inhibitor developed as the S-isomer of omeprazole to improve its pharmacokinetic properties. Reports of cutaneous reactions to proton-pump inhibitors are quite common, but reports of such reactions to esomeprazole are rare, which demonstrates the need for higher clinical awareness and knowledge of reactions to these drugs.

  9. A universal model for solar eruptions.

    PubMed

    Wyper, Peter F; Antiochos, Spiro K; DeVore, C Richard

    2017-04-26

    Magnetically driven eruptions on the Sun, from stellar-scale coronal mass ejections to small-scale coronal X-ray and extreme-ultraviolet jets, have frequently been observed to involve the ejection of the highly stressed magnetic flux of a filament. Theoretically, these two phenomena have been thought to arise through very different mechanisms: coronal mass ejections from an ideal (non-dissipative) process, whereby the energy release does not require a change in the magnetic topology, as in the kink or torus instability; and coronal jets from a resistive process involving magnetic reconnection. However, it was recently concluded from new observations that all coronal jets are driven by filament ejection, just like large mass ejections. This suggests that the two phenomena have physically identical origin and hence that a single mechanism may be responsible, that is, either mass ejections arise from reconnection, or jets arise from an ideal instability. Here we report simulations of a coronal jet driven by filament ejection, whereby a region of highly sheared magnetic field near the solar surface becomes unstable and erupts. The results show that magnetic reconnection causes the energy release via 'magnetic breakout'-a positive-feedback mechanism between filament ejection and reconnection. We conclude that if coronal mass ejections and jets are indeed of physically identical origin (although on different spatial scales) then magnetic reconnection (rather than an ideal process) must also underlie mass ejections, and that magnetic breakout is a universal model for solar eruptions.

  10. The effect of Emdogain gel on periodontal healing in replanted monkeys' teeth.

    PubMed

    Lam, Karen; Sae-Lim, Varawan

    2004-01-01

    We sought to histologically evaluate the effect of Emdogain gel on periodontal healing in monkeys' teeth undergoing delayed replantation. Study design Mature monkey teeth simulating avulsion were endodontically treated before extraction. Negative control teeth (group N = 10 roots) underwent immediate replantation, whereas the rest were bench-dried for 1 hour and treated in one of the following ways before replantation: the positive control teeth (group P = 12 roots) had no further treatment; group C teeth (4 roots) had the periodontal ligament removed; group D teeth (10 roots) were treated with Emdogain gel; group E teeth (6 roots) had the periodontal ligament removed before the application of Emdogain gel; and group F teeth (7 roots) had the periodontal ligament removed, the root surface conditioned, and Emdogain gel applied. Periodontal healing was evaluated after 16 weeks by undertaking histomorphometric analysis. The Kruskal-Wallis and Mann-Whitney U tests revealed that group N teeth had a statistically higher occurrence of complete healing than did all other groups, whereas group P was not significantly different in any of the healing categories from D, E, and F, the groups in which Emdogain gel was used. Group C teeth had a significantly higher occurrence of replacement root resorption than did the teeth in groups P and F-but were not significantly different from teeth in groups D and E. Emdogain gel did not appear to significantly reduce replacement resorption in monkeys' teeth that had undergone delayed replantation.

  11. Climatic impact of volcanic eruptions

    NASA Technical Reports Server (NTRS)

    Rampino, Michael R.

    1991-01-01

    Studies have attempted to 'isolate' the volcanic signal in noisy temperature data. This assumes that it is possible to isolate a distinct volcanic signal in a record that may have a combination of forcings (ENSO, solar variability, random fluctuations, volcanism) that all interact. The key to discovering the greatest effects of volcanoes on short-term climate may be to concentrate on temperatures in regions where the effects of aerosol clouds may be amplified by perturbed atmospheric circulation patterns. This is especially true in subpolar and midlatitude areas affected by changes in the position of the polar front. Such climatic perturbation can be detected in proxy evidence such as decrease in tree-ring widths and frost rings, changes in the treeline, weather anomalies, severity of sea-ice in polar and subpolar regions, and poor grain yields and crop failures. In low latitudes, sudden temperature drops were correlated with the passage overhead of the volcanic dust cloud (Stothers, 1984). For some eruptions, such as Tambora, 1815, these kinds of proxy and anectdotal information were summarized in great detail in a number of papers and books (e.g., Post, 1978; Stothers, 1984; Stommel and Stommel, 1986; C. R. Harrington, in press). These studies lead to the general conclusion that regional effects on climate, sometimes quite severe, may be the major impact of large historical volcanic aerosol clouds.

  12. Volcanic Eruptions in Kamchatka

    NASA Technical Reports Server (NTRS)

    2007-01-01

    [figure removed for brevity, see original site] [figure removed for brevity, see original site] Sheveluch Stratovolcano Click on the image for full resolution TIFF Klyuchevskoy Stratovolcano Click on the image for full resolution TIFF

    One of the most volcanically active regions of the world is the Kamchatka Peninsula in eastern Siberia, Russia. It is not uncommon for several volcanoes to be erupting at the same time. On April 26, 2007, the Advanced Spaceborne Thermal Emission and Reflection Radioneter (ASTER) on NASA's Terra spacecraft captured these images of the Klyuchevskoy and Sheveluch stratovolcanoes, erupting simultaneously, and 80 kilometers (50 miles) apart. Over Klyuchevskoy, the thermal infrared data (overlaid in red) indicates that two open-channel lava flows are descending the northwest flank of the volcano. Also visible is an ash-and-water plume extending to the east. Sheveluch volcano is partially cloud-covered. The hot flows highlighted in red come from a lava dome at the summit. They are avalanches of material from the dome, and pyroclastic flows.

    With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER images Earth to map and monitor the changing surface of our planet.

    ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra spacecraft. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products.

    The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping, and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining

  13. Dental eruption in East African wild chimpanzees.

    PubMed

    Machanda, Zarin; Brazeau, Nick F; Bernard, Andrew B; Donovan, Ronan M; Papakyrikos, Amanda M; Wrangham, Richard; Smith, Tanya M

    2015-05-01

    Knowledge of chimpanzee development has played an essential role in our understanding of the evolution of human ontogeny. However, recent studies of wild ape dentitions have cast doubt on the use of developmental standards derived from captive individuals. Others have called into question the use of deceased wild individuals to infer normative development. We conducted a high resolution photographic study of living known-age subadults in the Kanyawara community (Kibale National Park, Uganda) to generate a comprehensive three year record of dental eruption (including tooth emergence ages). These non-invasive data allow comparisons of captive and wild chimpanzees, establish accurate developmental standards for relatively healthy wild individuals, and facilitate direct assessments of primate-wide associations between dental development and life history. Emergence ages in the Kanyawara chimpanzees are very similar to living Gombe chimpanzees, and are broadly comparable to deceased Taï Forest chimpanzees. Early-emerging teeth such as the deciduous dentition and first molar (M1) appear during a time of maternal dependence, and are almost indistinguishable from captive chimpanzee emergence ages, while later forming teeth in the Kanyawara population emerge in the latter half of captive age ranges or beyond. Five juveniles whose lower M1s emerged by or before 3.3 years of age continued to nurse for a year or more beyond M1 emergence, and their mothers showed considerable variation in reproductive rates. The third molars of two adolescent females emerged several months to several years prior to the birth of their first offspring. Given that broad primate-wide relationships between molar emergence and life history do not necessarily hold within this population of chimpanzees, particularly for variables that are reported to be coincident with molar emergence, we suggest that further study is required in order to predict life history variables in hominins or hominoids

  14. Voyager 2 Jupiter Eruption Movie

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This movie records an eruptive event in the southern hemisphere of Jupiter over a period of 8 Jupiter days. Prior to the event, an undistinguished oval cloud mass cruised through the turbulent atmosphere. The eruption occurs over avery short time at the very center of the cloud. The white eruptive material is swirled about by the internal wind patterns of the cloud. As a result of the eruption, the cloud then becomes a type of feature seen elsewhere on Jupiter known as 'spaghetti bowls'.

    As Voyager 2 approached Jupiter in 1979, it took images of the planet at regular intervals. This sequence is made from 8 images taken once every Jupiter rotation period (about 10 hours). These images were acquired in the Violet filter around May 6, 1979. The spacecraft was about 50 million kilometers from Jupiter at that time.

    This time-lapse movie was produced at JPL by the Image Processing Laboratory in 1979.

  15. Histological observations of pulpal replacement tissue in immature dog teeth after revascularization of infected pulps.

    PubMed

    Saoud, Tarek Mohamed A; Zaazou, Ashraf; Nabil, Ahmed; Moussa, Sybel; Aly, Hanaa Mohamed; Okazaki, Katsushi; Rosenberg, Paul A; Lin, Louis M

    2015-06-01

    Many studies have examined the nature of tissue formed in the canals of immature necrotic teeth, following revascularization in animals and humans. While speculations have been made that regeneration of the pulp tissue might take place in the canal, the tissue has been found to be cementum-like, bone-like, and periodontal ligament-like. The purpose of this study was to histologically examine the tissue in the root canals in immature dog teeth that had been artificially infected and then revascularized. Two 4- to 5-month-old mongrel dogs with immature teeth were used in the study. In one dog, four maxillary and four mandibular anterior teeth, and in another dog, four maxillary and five mandibular anterior teeth were used in the experiment. Pulp infection was artificially induced in the immature teeth. Revascularization was performed on all teeth by disinfecting the root canals with sodium hypochlorite irrigation and triple antibiotic intracanal dressing, completed with induction of intracanal bleeding, and sealed with an MTA plug. The access cavity was restored with silver amalgam. The animals were sacrificed 3 months after revascularization procedures. The revascularized teeth and surrounding periodontal tissues were removed and prepared for histological examination. Besides cementum-like, bone-like, and periodontal ligament-like tissues formed in the canals, residual remaining pulp tissue was observed in two revascularized teeth. In four teeth, ingrowth of alveolar bone into the canals was seen; presence of bone in the root canals has the potential for ankylosis. Within the limitation of this study, it can be concluded that residual pulp tissue can remain in the canals after revascularization procedures of immature teeth with artificially induced pulp infection. This can lead to the misinterpretation that true pulpal regeneration has occurred. Ingrowth of apical bone into the root canals undergoing revascularization can interfere with normal tooth eruption if

  16. Assessing Eruption Column Height in Ancient Flood Basalt Eruptions

    NASA Technical Reports Server (NTRS)

    Glaze, Lori S.; Self, Stephen; Schmidt, Anja; Hunter, Stephen J.

    2015-01-01

    A buoyant plume model is used to explore the ability of flood basalt eruptions to inject climate-relevant gases into the stratosphere. An example from the 1986 Izu-Oshima basaltic fissure eruption validates the model's ability to reproduce the observed maximum plume heights of 12-16 km above sea level, sustained above fire-fountains. The model predicts maximum plume heights of 13-17 km for source widths of between 4-16 m when 32% (by mass) of the erupted magma is fragmented and involved in the buoyant plume (effective volatile content of 6 wt%). Assuming that the Miocene-age Roza eruption (part of the Columbia River Basalt Group) sustained fire-fountains of similar height to Izu-Oshima (1.6 km above the vent), we show that the Roza eruption could have sustained buoyant ash and gas plumes that extended into the stratosphere at approximately 45 deg N. Assuming 5 km long active fissure segments and 9000 Mt of SO2 released during explosive phases over a 10-15 year duration, the approximately 180 km of known Roza fissure length could have supported approximately 36 explosive events/phases, each with a duration of 3-4 days. Each 5 km fissure segment could have emitted 62 Mt of SO2 per day into the stratosphere while actively fountaining, the equivalent of about three 1991 Mount Pinatubo eruptions per day. Each fissure segment could have had one to several vents, which subsequently produced lava without significant fountaining for a longer period within the decades-long eruption. Sensitivity of plume rise height to ancient atmospheric conditions is explored. Although eruptions in the Deccan Traps (approximately 66 Ma) may have generated buoyant plumes that rose to altitudes in excess of 18 km, they may not have reached the stratosphere because the tropopause was substantially higher in the late Cretaceous. Our results indicate that some flood basalt eruptions, such as Roza, were capable of repeatedly injecting large masses of SO2 into the stratosphere. Thus sustained

  17. Assessing eruption column height in ancient flood basalt eruptions

    NASA Astrophysics Data System (ADS)

    Glaze, Lori S.; Self, Stephen; Schmidt, Anja; Hunter, Stephen J.

    2017-01-01

    A buoyant plume model is used to explore the ability of flood basalt eruptions to inject climate-relevant gases into the stratosphere. An example from the 1986 Izu-Oshima basaltic fissure eruption validates the model's ability to reproduce the observed maximum plume heights of 12-16 km above sea level, sustained above fire-fountains. The model predicts maximum plume heights of 13-17 km for source widths of between 4-16 m when 32% (by mass) of the erupted magma is fragmented and involved in the buoyant plume (effective volatile content of 6 wt%). Assuming that the Miocene-age Roza eruption (part of the Columbia River Basalt Group) sustained fire-fountains of similar height to Izu-Oshima (1.6 km above the vent), we show that the Roza eruption could have sustained buoyant ash and gas plumes that extended into the stratosphere at ∼ 45 ° N. Assuming 5 km long active fissure segments and 9000 Mt of SO2 released during explosive phases over a 10-15 year duration, the ∼ 180km of known Roza fissure length could have supported ∼36 explosive events/phases, each with a duration of 3-4 days. Each 5 km fissure segment could have emitted 62 Mt of SO2 per day into the stratosphere while actively fountaining, the equivalent of about three 1991 Mount Pinatubo eruptions per day. Each fissure segment could have had one to several vents, which subsequently produced lava without significant fountaining for a longer period within the decades-long eruption. Sensitivity of plume rise height to ancient atmospheric conditions is explored. Although eruptions in the Deccan Traps (∼ 66Ma) may have generated buoyant plumes that rose to altitudes in excess of 18 km, they may not have reached the stratosphere because the tropopause was substantially higher in the late Cretaceous. Our results indicate that some flood basalt eruptions, such as Roza, were capable of repeatedly injecting large masses of SO2 into the stratosphere. Thus sustained flood basalt eruptions could have influenced

  18. Human Life History Evolution Explains Dissociation between the Timing of Tooth Eruption and Peak Rates of Root Growth

    PubMed Central

    Dean, M. Christopher; Cole, Tim J.

    2013-01-01

    We explored the relationship between growth in tooth root length and the modern human extended period of childhood. Tooth roots provide support to counter chewing forces and so it is advantageous to grow roots quickly to allow teeth to erupt into function as early as possible. Growth in tooth root length occurs with a characteristic spurt or peak in rate sometime between tooth crown completion and root apex closure. Here we show that in Pan troglodytes the peak in root growth rate coincides with the period of time teeth are erupting into function. However, the timing of peak root velocity in modern humans occurs earlier than expected and coincides better with estimates for tooth eruption times in Homo erectus. With more time to grow longer roots prior to eruption and smaller teeth that now require less support at the time they come into function, the root growth spurt no longer confers any advantage in modern humans. We suggest that a prolonged life history schedule eventually neutralised this adaptation some time after the appearance of Homo erectus. The root spurt persists in modern humans as an intrinsic marker event that shows selection operated, not primarily on tooth tissue growth, but on the process of tooth eruption. This demonstrates the overarching influence of life history evolution on several aspects of dental development. These new insights into tooth root growth now provide an additional line of enquiry that may contribute to future studies of more recent life history and dietary adaptations within the genus Homo. PMID:23342167

  19. Modeling lunar volcanic eruptions

    NASA Technical Reports Server (NTRS)

    Housley, R. M.

    1978-01-01

    Simple physical arguments are used to show that basaltic volcanos on different planetary bodies would fountain to the same height if the mole fraction of gas in the magma scaled with the acceleration of gravity. It is suggested that the actual eruption velocities and fountain heights are controlled by the velocities of sound in the two phase gas/liquid flows. These velocities are in turn determined by the gas contents in the magma. Predicted characteristics of Hawaiian volcanos are in excellent accord with observations. Assuming that the only gas in lunar volcano is the CO which would be produced if the observed Fe metal in lunar basalts resulted from graphite reduction, lunar volcanos would fountain vigorously, but not as spectacularly as their terrestrial counterparts. The volatile trace metals, halogens, and sulfur released would be transported over the entire moon by the transient atmosphere. Orange and black glass type pyroclastic materials would be transported in sufficient amounts to produce the observed dark mantle deposits.

  20. Solar Activity and Solar Eruptions

    NASA Technical Reports Server (NTRS)

    Sterling, Alphonse C.

    2006-01-01

    Our Sun is a dynamic, ever-changing star. In general, its atmosphere displays major variation on an 11-year cycle. Throughout the cycle, the atmosphere occasionally exhibits large, sudden outbursts of energy. These "solar eruptions" manifest themselves in the form of solar flares, filament eruptions, coronal mass ejections (CMEs), and energetic particle releases. They are of high interest to scientists both because they represent fundamental processes that occur in various astrophysical context, and because, if directed toward Earth, they can disrupt Earth-based systems and satellites. Research over the last few decades has shown that the source of the eruptions is localized regions of energy-storing magnetic field on the Sun that become destabilized, leading to a release of the stored energy. Solar scientists have (probably) unraveled the basic outline of what happens in these eruptions, but many details are still not understood. In recent years we have been studying what triggers these magnetic eruptions, using ground-based and satellite-based solar observations in combination with predictions from various theoretical models. We will present an overview of solar activity and solar eruptions, give results from some of our own research, and discuss questions that remain to be explored.

  1. Human teeth biobank: Microbiological analysis of the teeth storage solution.

    PubMed

    Curylofo-Zotti, Fabiana Almeida; Lorencetti-Silva, Francine; de Almeida Coelho, Jéssica; Monteiro, Rachel Maciel; Watanabe, Evandro; Corona, Silmara Aparecida Milori

    2018-01-17

    The cross-infections may occur during handling of dental elements, affecting the health of dental practitioners and researchers. This study aimed to analyze the influence of the storage medium temperature on the bacterial contingent of the human teeth used for research purposes. Thirty human teeth were donated to the Human Teeth Biobank immediately after extraction. The teeth were cleaned with tap water and neutral soap. The teeth were randomly distributed according to the temperature of the storage solution (deionized water): at 4 °C (refrigerator) or at -10 °C (freezer) and were stored individually in sterile vials during 60 days. After this period, a microbiological analysis (CFU/mL) of the storage solutions was performed and teeth were submitted to SEM analysis. Data were analyzed by Kruskal-Wallis test followed by Dunn's post-test (p ≤ .05). Total aerobic bacteria ranged from 5.8 to 8.4 log10 CFU/mL for refrigerated solution and from 1.9 to 8.5 log10 CFU/mL for frozen solution. No statistical differences were found between the storage solutions (p > .05). The counts of Streptococcus spp., Lactobacillus spp., and Staphylococcus spp. were similar for both storage solutions (p > .05). SEM analysis showed spiral- and rod-shaped bacteria attached on teeth stored under 4 °C, which may suggest the presence of Treponema spp. and Lactobacillus spp. Similar morphological forms were found on teeth stored under -10 °C. A biofilm organized in honeycomb-like form was found in the frozen teeth. Cocci were eventually found in all the samples. It was concluded that bacterial growth and survival were not influenced by the temperature of the teeth storage solution. © 2017 Wiley Periodicals, Inc.

  2. Characterization of pyroclastic deposits and pre-eruptive soils following the 2008 eruption of Kasatochi Island Volcano, Alaska

    USGS Publications Warehouse

    Wang, B.; Michaelson, G.; Ping, C.-L.; Plumlee, G.; Hageman, P.

    2010-01-01

    The 78 August 2008 eruption of Kasatochi Island volcano blanketed the island in newly generated pyroclastic deposits and deposited ash into the ocean and onto nearby islands. Concentrations of water soluble Fe, Cu, and Zn determined from a 1:20 deionized water leachate of the ash were sufficient to provide short-term fertilization of the surface ocean. The 2008 pyroclastic deposits were thicker in concavities at bases of steeper slopes and thinner on steep slopes and ridge crests. By summer 2009, secondary erosion had exposed the pre-eruption soils along gulley walls and in gully bottoms on the southern and eastern slopes, respectively. Topographic and microtopographic position altered the depositional patterns of the pyroclastic flows and resulted in pre-eruption soils being buried by as little as 1 m of ash. The different erosion patterns gave rise to three surfaces on which future ecosystems will likely develop: largely pre-eruptive soils; fresh pyroclastic deposits influenced by shallowly buried, pre-eruptive soil; and thick (>1 m) pyroclastic deposits. As expected, the chemical composition differed between the pyroclastic deposits and the pre-eruptive soils. Pre-eruptive soils hold stocks of C and N important for establishing biota that are lacking in the fresh pyroclastic deposits. The pyroclastic deposits are a source for P and K but have negligible nutrient holding capacity, making these elements vulnerable to leaching loss. Consequently, the pre-eruption soils may also represent an important long-term P and K source. ?? 2010 Regents of the University of Colorado.

  3. [Research progress on the cellular and molecular mechanisms of tooth eruption].

    PubMed

    Shiyan, Huang; Nanquan, Rao; Shuhao, Xu; Xiaobing, Li

    2016-06-01

    Tooth eruption is a series of complicated physiological processes occurring once the crown is formed completely, as well as when the tooth moves toward the occasion plane. As such, the tooth moves through the alveolar bone and the oral mucosa until it finally reaches its functional position. Most studies indicate that the process of tooth eruption involves the alveolar bone, dental follicles, osteoclasts, osteoblasts, and multiple cytokines. Dental follicles regulate both resorption and formation of the alveolar bone, which is required for tooth eruption. Furthermore, root formation with periodontal ligament facilitates continuous tooth eruption. However, the exact mechanism underlying tooth eruption remains unclear. Hence, this review describes the recent research progress on the cellular and molecular mechanisms of tooth eruption.

  4. Mouth and Teeth (For Parents)

    MedlinePlus

    ... Aid & Safety Doctors & Hospitals Videos Recipes for Kids Kids site Sitio para niños How the Body Works Puberty & Growing Up Staying Healthy Staying Safe ... Answers Q&A Movies & More for Teens Teens site Sitio para ... / For Parents / Mouth and Teeth What's in this article? Basic Anatomy of the Mouth and Teeth Normal Development of ...

  5. Sterilization of Extracted Human Teeth.

    ERIC Educational Resources Information Center

    Pantera, Eugene A., Jr.; Schuster, George S.

    1990-01-01

    At present, there is no specific recommendation for sterilization of extracted human teeth used in dental technique courses. The purpose of this study was to determine whether autoclaving would be effective in the sterilization of extracted teeth without compromising the characteristics that make their use in clinical simulations desirable. (MLW)

  6. Management and Sequelae of Intruded Anterior Primary Teeth: A Systematic Review

    PubMed Central

    Murugan, Muthu; Somasundaram, Sujatha

    2016-01-01

    Objective The objective of this systematic review is to analyze the various treatment modalities and sequelae of intruded anterior primary teeth. Materials and methods Electronic search in PubMed, Cochrane, and Science Direct databases was done. Hand search was performed using the reference list of chosen articles from electronic search. Three reviewers analyzed the articles independently, assessed the quality of the studies, and derived data. Results Ten case series were identified from the electronic and hand search. No randomized control studies were available. In the observational studies treatment of intruded primary teeth ranged from conservative management, which includes waiting for spontaneous re-eruption as well as repositioning to invasive procedure, such as extraction. Conclusion Spontaneous eruption is a treatment option of intruded primary teeth in absence of damage to a permanent tooth. Surgical repositioning of intruded primary teeth has also shown as a viable alternative treatment modality. Extraction to be performed if complications develop. How to cite this article Gurunathan D, Murugan M, Somasundaram S. Management and Sequelae of Intruded Anterior Primary Teeth: A Systematic Review. Int J Clin Pediatr Dent 2016;9(3):240-250. PMID:27843257

  7. [Nutrition, diet and dental health--de- and remineralisation of teeth].

    PubMed

    Imfeld, Thomas

    2008-02-01

    There is little if any evidence that nutrition during the time of tooth formation has any clinically significant effect on caries susceptibility of erupted teeth in man. Caries, erosion and demastication are not nutritional diseases. They are, however, diet-related diseases because erupted teeth are subject to local chemical and mechanical effects of the diet contacting the teeth. Caries is the result of a chronic undermining demineralisation of the teeth by organic acids that are produced by the bacteria of the dental biofilm while fermenting carbohydrates from the human diet. Dental erosion is the result of a chronic localised loss of dental hard tissue etched away from the surface by acids derived from the diet or from gastric reflux. The physicochemical grounds of de- and remineralisation of teeth are explained using detailed diagrams. Initial caries lesions without cavitation of the surface can remineralise (heal) under conditions of low cariogenic diet and good oral hygiene. However, once the surface has broken and cavitation occurred, there is no alternative to restorative dental therapy because remineralisation is no more possible.

  8. Pathological studies of cheek teeth apical infections in the horse: 1. Normal endodontic anatomy and dentinal structure of equine cheek teeth.

    PubMed

    Dacre, I T; Kempson, S; Dixon, P M

    2008-12-01

    Morphological examinations were performed on 100 normal equine cheek teeth (CT) of 1-12 years dental age (i.e. time since eruption), using gross examination, dissection microscopy, computerised axial tomography, and decalcified and undecalcified histology. The CT in Triadan 07-10 positions consistently had five pulp horns, but the 06 CT had an additional pulp horn more rostrally. Mandibular and maxillary Triadan 11s had six and seven pulp horns, respectively. Sections of CT taken 2-6mm below the occlusal surface (variation due to normal undulating occlusal surface) showed the presence of pulp in up to 50% of individual maxillary CT pulp horns, and in up to 25% of individual mandibular CT pulp horns. The histological appearances of primary and secondary dentine were described and it is proposed that the type of dentine present most centrally in every pulp chamber examined, currently termed tertiary dentine, should be re-classified as irregular secondary dentine, and that the term tertiary dentine be reserved for the focal areas of dentine laid down following insult to dentine or pulp.

  9. Microabrasion of teeth with discoloration resembling hypomaturation enamel defects: four-year follow up.

    PubMed

    Ashkenazi, M; Sarnat, H

    2000-01-01

    Microabrasion with 18% HCl and pumice to remove enamel dysmineralization and improve esthetics is an accepted and effective treatment. This technique can probably be extended even to generalized defects resembling hypomaturation amelogenesis imperfecta that appear on all erupted teeth. Five children aged 9 to 11 with two types of enamel-hypomaturation probably due to developmental defects were treated successfully by microabrasion, with marked improvement of the discoloration. The patients were followed for up to four years. During this period, no tooth-sensitivity or staining was noted. The teeth looked healthier and shinier.

  10. Signs and Symptoms of Primary Tooth Eruption: A Meta-analysis.

    PubMed

    Massignan, Carla; Cardoso, Mariane; Porporatti, André Luís; Aydinoz, Secil; Canto, Graziela De Luca; Mezzomo, Luis Andre Mendonça; Bolan, Michele

    2016-03-01

    Symptoms associated with the primary tooth eruption have been extensively studied but it is still controversial. To assess the occurrence of local and systemic signs and symptoms during primary tooth eruption. Latin American and Caribbean Health Sciences, PubMed, ProQuest, Scopus, and Web of Science were searched. A partial gray literature search was taken by using Google Scholar and the reference lists of the included studies were scanned. Observational studies assessing the association of eruption of primary teeth with local and systemic signs and symptoms in children aged 0 to 36 months were included. Two authors independently collected the information from the selected articles. Information was crosschecked and confirmed for its accuracy. A total of 1179 articles were identified, and after a 2-phase selection, 16 studies were included. Overall prevalence of signs and symptoms occurring during primary tooth eruption in children between 0 and 36 months was 70.5% (total sample = 3506). Gingival irritation (86.81%), irritability (68.19%), and drooling (55.72%) were the most frequent ones. Different general symptoms were considered among studies. Some studies presented lack of confounding factors, no clear definition of the diagnostics methods, use of subjective measures and long intervals between examinations. There is evidence of the occurrence of signs and symptoms during primary tooth eruption. For body temperature analyses, eruption could lead to a rise in temperature, but it was not characterized as fever. Copyright © 2016 by the American Academy of Pediatrics.

  11. Take Care of Your Teeth and Gums

    MedlinePlus

    ... Brush your teeth 2 times a day with fluoride (“FLOOR-ide”) toothpaste. Floss between your teeth every ... a toothbrush with soft bristles and toothpaste with fluoride. Fluoride is a mineral that helps protect teeth ...

  12. Explosion Quakes: The 2007 Eruption of Pavlof

    NASA Astrophysics Data System (ADS)

    Smith, C.; McNutt, S. R.; Thompson, G.

    2014-12-01

    Pavlof Volcano on the Alaska Peninsula began to erupt on August 14, 2007 after an 11 year repose. Pavlof is the most active volcano in the Aleutians, with over 40 eruptions in historical times. The 2007 eruption began with low-frequency earthquakes and thermal anomalies. Strombolian activity occurred from a newly formed vent on the SE flank of the volcano. The plume reached 20,000 ft during the peak of the eruption on August 29th and 30th. Seismic activity, monitored by a network of 5 local instruments, consisted of low-frequency events, explosion quakes, volcanic tremor, and lahar-generated signals. Here we focus on explosion quakes. The first explosion quake occurred August 14th at 2:54pm UTC and the last on September 13th at 3:14pm UTC. Explosion events were often embedded in continuous tremor, but could be distinguished by the ground-coupled air waves, which appeared as a high-frequency spike superimposed on the lower-frequency ground waves. Rates were as high as 19 explosion quakes per minute. We establish whether systematic changes in explosion rates, signal properties, and ground-coupled air-wave amplitudes correlate with the height and ash content of the plume. First order trends show a positive correlation between increased explosion quake rates, increased amplitudes, and plume height. In addition, we investigate how atmospheric conditions such as wind speed and direction affect the recording of the ground-coupled air-wave. The time differences in the airwaves at different stations are consistent with the acoustic speed of 340 m/s, but show variations of up to 0.6 s depending on wind speed and direction. Eruptions at Pavlof typically have little or no seismic precursors; this combined with the low visibility common to the area results in Pavlof being dangerous to the many aviation routes that transverse this airspace. It is the goal of this study to determine the conditions under which explosion quake data may be reliably used for more effective monitoring.

  13. Hubble Captures Volcanic Eruption Plume From Io

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The Hubble Space Telescope has snapped a picture of a 400-km-high (250-mile-high) plume of gas and dust from a volcanic eruption on Io, Jupiter's large innermost moon.

    Io was passing in front of Jupiter when this image was taken by the Wide Field and Planetary Camera 2 in July 1996. The plume appears as an orange patch just off the edge of Io in the eight o'clock position, against the blue background of Jupiter's clouds. Io's volcanic eruptions blasts material hundreds of kilometers into space in giant plumes of gas and dust. In this image, material must have been blown out of the volcano at more than 2,000 mph to form a plume of this size, which is the largest yet seen on Io.

    Until now, these plumes have only been seen by spacecraft near Jupiter, and their detection from the Earth-orbiting Hubble Space Telescope opens up new opportunities for long-term studies of these remarkable phenomena.

    The plume seen here is from Pele, one of Io's most powerful volcanos. Pele's eruptions have been seen before. In March 1979, the Voyager 1 spacecraft recorded a 300-km-high eruption cloud from Pele. But the volcano was inactive when the Voyager 2 spacecraft flew by Jupiter in July 1979. This Hubble observation is the first glimpse of a Pele eruption plume since the Voyager expeditions.

    Io's volcanic plumes are much taller than those produced by terrestrial volcanos because of a combination of factors. The moon's thin atmosphere offers no resistance to the expanding volcanic gases; its weak gravity (one-sixth that of Earth) allows material to climb higher before falling; and its biggest volcanos are more powerful than most of Earth's volcanos.

    This image is a contrast-enhanced composite of an ultraviolet image (2600 Angstrom wavelength), shown in blue, and a violet image (4100 Angstrom wavelength), shown in orange. The orange color probably occurs because of the absorption and/or scattering of ultraviolet light in the plume. This light from Jupiter passes through

  14. Measuring Rabbit (Oryctolagus cuniculus) Tooth Growth and Eruption by Fluorescence Markers and Bur Marks.

    PubMed

    Wyss, Fabia; Müller, Jacqueline; Clauss, Marcus; Kircher, Patrick; Geyer, Hans; von Rechenberg, Brigitte; Hatt, Jean-Michel

    2016-03-01

    Rabbits (Oryctolagus cuniculus) and rodents possess continuously growing teeth, and dental problems are a major health issue in these species. Knowledge of tooth growth characteristics is required to adequately treat dental problems and advise owners concerning diets. Most research was performed using bur marks and measuring eruption and wear manually. However, this method cannot be applied to teeth less rostral than the first premolar; therefore, for evaluation of molars, other methods are needed. We evaluated the use of fluorochromes xylenol orange and calcein green to measure growth rates of rabbit teeth and compared this method to results obtained by manually measuring the distance between a bur mark and the gingival margin of the same tooth (eruption) and by measuring the distance between the bur mark and the apex of the same tooth on computed tomography scans (growth). Apical fluorochrome measurements correlated well with eruption and growth rates obtained with bur marks, whereas measurements coronal to the pulp cavity did not. Growth rates were approximately 1.9 mm/wk for maxillary and 2.2 mm/wk for mandibular incisors. Growth rates of premolars were 2.14 ± 0.28 mm/wk in rabbits on a grass/rice hulls/sand pelleted diet and 0.93 ± 0.18 mm/wk in rabbits on a hay diet. Growth of molars could only be assessed using the measurement in dentin on the wall of the pulp cavity, which does not account for the real growth. However, being similar to this measurement in premolars, one could hypothesize similar growth in molars as in premolars. We conclude that the application of fluorochrome staining can be used to measure tooth growth in teeth that are not accessible for bur marks or in animals that are too small to assess tooth eruption or growth by bur marks.

  15. Dental maturation, eruption, and gingival emergence in the upper jaw of newborn primates

    PubMed Central

    Smith, Timothy D.; Muchlinksi, Magdalena N.; Jankord, Kathryn D.; Progar, Abbigal J.; Bonar, Christopher J.; Evans, Sian; Williams, Lawrence; Vinyard, Christopher J.; DeLeon, Valerie B.

    2015-01-01

    In this report we provide data on dental eruption and tooth germ maturation at birth in a large sample constituting the broadest array of non-human primates studied to date. Over 100 perinatal primates, obtained from natural captive deaths, were screened for characteristics indicating premature birth, and were subsequently studied using a combination of histology and micro-CT. Results reveal one probable unifying characteristic of living primates: relatively advanced maturation of deciduous teeth and M1 at birth. Beyond this, there is great diversity in the status of tooth eruption and maturation (dental stage) in the newborn primate. Contrasting strategies in producing a masticatory battery are already apparent at birth in strepsirrhines and anthropoids. Results show that dental maturation and eruption schedules are potentially independently co-opted as different strategies for attaining feeding independence. The most common strategy in strepsirrhines is accelerating eruption and the maturation of the permanent dentition, including replacement teeth. Anthropoids, with only few exceptions, accelerate mineralization of the deciduous teeth, while delaying development of all permanent teeth except M1. These results also show that no living primate resembles the altricial tree shrew (Tupaia) in dental development. Our preliminary observations suggest that ecological explanations, such as diet, provide an explanation for certain morphological variations at birth. These results confirm previous work on perinatal indriids indicating that these and other primates telegraph their feeding adaptations well before masticatory anatomy is functional. Quantitative analyses are required to decipher specific dietary and other influences on dental size and maturation in the newborn primate. PMID:26425925

  16. Orthodontic treatment of impacted anterior teeth due to odontomas: a report of two cases.

    PubMed

    Batra, Puneet; Duggal, Ritu; Kharbanda, Om Prakash; Parkash, Hari

    2004-01-01

    Two cases are presented where the odontomas had caused the impaction of the anterior teeth and required a combined surgical and orthodontic treatment to bring these teeth into the arch. In the first case a large a complex odontome had caused the impaction of the right central incisor, lateral incisor and canine. In the second case a compound odontome blocked the eruption pathway of the right central incisor. It is emphasised that radiographic examination of all pediatric patients that present clinical evidence of delayed permanent tooth eruption or temporary tooth displacement with or without a history of previous dental trauma should be performed. Early diagnosis of odontomas allows adoption of a less complex and less expensive treatment and ensures a better prognosis.

  17. A Curriculum Vitae of Teeth: Evolution, Generation, Regeneration

    PubMed Central

    Koussoulakou, Despina S.; Margaritis, Lukas H.; Koussoulakos, Stauros L.

    2009-01-01

    The ancestor of recent vertebrate teeth was a tooth-like structure on the outer body surface of jawless fishes. Over the course of 500,000,000 years of evolution, many of those structures migrated into the mouth cavity. In addition, the total number of teeth per dentition generally decreased and teeth morphological complexity increased. Teeth form mainly on the jaws within the mouth cavity through mutual, delicate interactions between dental epithelium and oral ectomesenchyme. These interactions involve spatially restricted expression of several, teeth-related genes and the secretion of various transcription and signaling factors. Congenital disturbances in tooth formation, acquired dental diseases and odontogenic tumors affect millions of people and rank human oral pathology as the second most frequent clinical problem. On the basis of substantial experimental evidence and advances in bioengineering, many scientists strongly believe that a deep knowledge of the evolutionary relationships and the cellular and molecular mechanisms regulating the morphogenesis of a given tooth in its natural position, in vivo, will be useful in the near future to prevent and treat teeth pathologies and malformations and for in vitro and in vivo teeth tissue regeneration. PMID:19266065

  18. A curriculum vitae of teeth: evolution, generation, regeneration.

    PubMed

    Koussoulakou, Despina S; Margaritis, Lukas H; Koussoulakos, Stauros L

    2009-01-01

    The ancestor of recent vertebrate teeth was a tooth-like structure on the outer body surface of jawless fishes. Over the course of 500,000,000 years of evolution, many of those structures migrated into the mouth cavity. In addition, the total number of teeth per dentition generally decreased and teeth morphological complexity increased. Teeth form mainly on the jaws within the mouth cavity through mutual, delicate interactions between dental epithelium and oral ectomesenchyme. These interactions involve spatially restricted expression of several, teeth-related genes and the secretion of various transcription and signaling factors. Congenital disturbances in tooth formation, acquired dental diseases and odontogenic tumors affect millions of people and rank human oral pathology as the second most frequent clinical problem. On the basis of substantial experimental evidence and advances in bioengineering, many scientists strongly believe that a deep knowledge of the evolutionary relationships and the cellular and molecular mechanisms regulating the morphogenesis of a given tooth in its natural position, in vivo, will be useful in the near future to prevent and treat teeth pathologies and malformations and for in vitro and in vivo teeth tissue regeneration.

  19. Dental anomalies in primary dentition and their corresponding permanent teeth.

    PubMed

    Gomes, R R; Fonseca, J A C; Paula, L M; Acevedo, A C; Mestrinho, H D

    2014-05-01

    The objectives of this paper are to estimate the prevalence of dental anomalies in primary dentition in a sample of 2- to 5-year-old Brazilian preschool children, determine their distribution, and investigate their occurrence in the succedaneous teeth of the sample compared with a control group of children with no dental anomalies in the primary dentition. The one-stage sample comprised 1,718 two to five-year-old children with fully erupted primary dentition clinically examined for dental anomalies. All children presenting dental anomalies underwent panoramic radiographs. Descriptive statistics were performed for the studied variables. A control group matched by sex and age was studied to compare the prevalence ratio for dental anomalies in the permanent dentition. The prevalence of dental anomalies in the primary dentition was 1.8 %, with no significant statistical difference between sexes. Double teeth were the most frequently observed. Dental anomalies on the succedaneous permanent teeth were diagnosed in 54.8 % of the children with affected primary dentition. The prevalence ratio (PR) for dental anomalies in the succedaneous permanent teeth was 17.1 (confidence interval (CI) 5.33-54.12) higher compared with the control group, higher in children with bilateral anomalies (PR = 31.2, CI 10.18-94.36). An association between anomalies of the permanent dentition and the presence of dental anomalies in primary teeth was observed, especially when they occur bilaterally. The results in the present study have a clinical relevance in the diagnosis of children with dental anomalies in primary dentition. Early identification of these anomalies can aid the dentist in planning dental treatment at the appropriate time.

  20. Featured Image: Solar Prominence Eruptions

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-02-01

    In these images from the Solar Dynamics Observatorys AIA instrument (click for the full resolution!), two solar prominence eruptions (one from June 2011 and one from August 2012) are shown in pre- and post-eruption states. The images at the top are taken in the Fe XII 193 bandpass and the images at the bottom are taken in the He II 304 bandpass. When a team of scientists searched through seven years of solar images taken by the STEREO (Solar Terrestrial Relations Observatory) spacecraft, these two eruptions were found to extend all the way out to a distance of 1 AU. They were the only two examples of clear, bright, and compact prominence eruptions found to do so. The scientists, led by Brian Wood (Naval Research Laboratory), used these observations to reconstruct the motion of the eruption and model how prominences expand as they travel away from the Sun. Theimage to the rightshowsa STEREO observation compared to the teams 3D model of theprominences shape and expansion. To learn more about theresults from this study, check out the paper below.CitationBrian E. Wood et al 2016 ApJ 816 67. doi:10.3847/0004-637X/816/2/67

  1. Rhyolite magma processes of the ˜AD 1315 Kaharoa eruption episode, Tarawera volcano, New Zealand

    NASA Astrophysics Data System (ADS)

    Nairn, I. A.; Shane, P. R.; Cole, J. W.; Leonard, G. J.; Self, S.; Pearson, N.

    2004-03-01

    Products of the ˜5 km 3 (DRE), ˜5-yr duration Kaharoa eruption episode display two main high-silica rhyolite compositions; T1 erupted early (as plinian pyroclastics), and T2 erupted late (mostly as lavas). The T1 and T2 eruptive types are defined by crystal contents and compositional variations in whole rock, glass, plagioclase and biotite. Stratigraphically intermediate pyroclastic deposits have an intermediate composition (T1+2). A small volume of rhyodacite pyroclastics, mingled with injected basalt, was also erupted. The Kaharoa rhyolites were erupted from multiple sources spread along an 8-km linear vent zone, but the changes in eruptive compositions were largely controlled by position in the eruption sequence and magma discharge rates, rather than vent locations. Data from the Kaharoa eruptive types, vent locations, eruption sequence and discharge rates can be combined with concepts of magma chamber evacuation processes to produce a preliminary dimensional model of the pre-eruption rhyolite magma body. Our model magma body is sill-like, ˜8 km long, 1 km wide, 1.4 km thick, and located at ˜6-7 km depth in the upper crust. T1 magma overlay T2 magma in the upper levels of the chamber, with each magma layer internally mixed to a homogeneous composition along an axial extent defined by the vent locations. An underlying third rhyolite magma (T3) is recognised as the silicic end-member that was modified by basalt to form the rhyodacite eruptives. The rhyolite magma stratification survived multiple injections of basalt magma, which primed and finally triggered the Kaharoa eruptions. The T1+2 eruptives resulted from syn-eruption mingling in the conduit of the two main rhyolite magma types. Thickness of the T1 layer in the model can be estimated at 0.25 km; the T2 layer was somewhat thicker. Thicknesses of the underlying T3 and basalt layers are uncertain. Post-eruption geothermal heat flow indicates a residual magma volume of ≥6 km 3, suggesting that the pre-eruption

  2. The relationships between the arrangement of teeth, root resorption, and dental maturity in bovine mandibular incisors

    PubMed Central

    An, Jin-kyu; Ono, Takashi

    2017-01-01

    Objective The objective of this study is to investigate the eruption pattern and root resorption of the bovine anterior dentition in relation to growth-related parameters based on dental maturity. Methods A cross-sectional study was conducted on 110 bovine anterior mandibles by using standard radiography, cone-beam computed tomography (CBCT), and actual measurements. We determined the relationships between the stages of dental maturity by using a modification of Demirjian's method and various growth-related parameters, such as the activity of the root-resorbing tissue and mobility of the deciduous teeth. The correlation of growth-related parameters with interdental spacing and distal unusual root resorption (DRR) of the deciduous fourth incisor was assessed. The cause of mesial unusual root resorption (MRR) of the deciduous fourth incisor was determined on the basis of the arrangement of the permanent third incisor. Results An independent t-test and chi-square test indicated significant differences in growth-related parameters associated with dental arch length discrepancy and factors related to the shedding of deciduous teeth between the low and high dental maturity groups. The samples with interdental spacing and DRR showed a larger sum of mesiodistal permanent crown widths and higher dental maturity than did the respective controls. Samples with MRR tended to show a lingually rotated distal tip of the adjacent tooth crown. Conclusions Dental maturity has relevance to the interdental spaces and unusual root resorption of mixed dentition. The position of the adjacent tooth crown on CBCT may be correlated with the occurrence of unusual root resorption of the incisor. PMID:29090124

  3. Can rain cause volcanic eruptions?

    USGS Publications Warehouse

    Mastin, Larry G.

    1993-01-01

    Volcanic eruptions are renowned for their violence and destructive power. This power comes ultimately from the heat and pressure of molten rock and its contained gases. Therefore we rarely consider the possibility that meteoric phenomena, like rainfall, could promote or inhibit their occurrence. Yet from time to time observers have suggested that weather may affect volcanic activity. In the late 1800's, for example, one of the first geologists to visit the island of Hawaii, J.D. Dana, speculated that rainfall influenced the occurrence of eruptions there. In the early 1900's, volcanologists suggested that some eruptions from Mount Lassen, Calif., were caused by the infiltration of snowmelt into the volcano's hot summit. Most such associations have not been provable because of lack of information; others have been dismissed after careful evaluation of the evidence.

  4. Climate response to the Samalas volcanic eruption in 1257 revealed by proxy records

    NASA Astrophysics Data System (ADS)

    Guillet, Sébastien; Corona, Christophe; Stoffel, Markus; Khodri, Myriam; Lavigne, Franck; Ortega, Pablo; Eckert, Nicolas; Sielenou, Pascal Dkengne; Daux, Valérie; Churakova (Sidorova), Olga V.; Davi, Nicole; Edouard, Jean-Louis; Zhang, Yong; Luckman, Brian H.; Myglan, Vladimir S.; Guiot, Joël; Beniston, Martin; Masson-Delmotte, Valérie; Oppenheimer, Clive

    2017-01-01

    The eruption of Samalas in Indonesia in 1257 ranks among the largest sulfur-rich eruptions of the Common Era with sulfur deposition in ice cores reaching twice the volume of the Tambora eruption in 1815. Sedimentological analyses of deposits confirm the exceptional size of the event, which had both an eruption magnitude and a volcanic explosivity index of 7. During the Samalas eruption, more than 40 km3 of dense magma was expelled and the eruption column is estimated to have reached altitudes of 43 km. However, the climatic response to the Samalas event is debated since climate model simulations generally predict a stronger and more prolonged surface air cooling of Northern Hemisphere summers than inferred from tree-ring-based temperature reconstructions. Here, we draw on historical archives, ice-core data and tree-ring records to reconstruct the spatial and temporal climate response to the Samalas eruption. We find that 1258 and 1259 experienced some of the coldest Northern Hemisphere summers of the past millennium. However, cooling across the Northern Hemisphere was spatially heterogeneous. Western Europe, Siberia and Japan experienced strong cooling, coinciding with warmer-than-average conditions over Alaska and northern Canada. We suggest that in North America, volcanic radiative forcing was modulated by a positive phase of the El Niño-Southern Oscillation. Contemporary records attest to severe famines in England and Japan, but these began prior to the eruption. We conclude that the Samalas eruption aggravated existing crises, but did not trigger the famines.

  5. Automated estimation of mass eruption rate of volcanic eruption on satellite imagery using a cloud pattern recognition algorithm

    NASA Astrophysics Data System (ADS)

    Pouget, Solene; Jansons, Emile; Bursik, Marcus; Tupper, Andrew; Patra, Abani; Pitman, Bruce; Carn, Simon

    2014-05-01

    The need to detect and track the position of ash in the atmosphere has been highlighted in the past few years following the eruption Eyjafjallajokull. As a result, Volcanic Ash Advisory Centers (VAACs) are using Volcanic Ash Transport and Dispersion models (VATD) to estimate and predict the whereabouts of the ash in the atmosphere. However, these models require inputs of eruption source parameters, such as the mass eruption rate (MER), and wind fields, which are vital to properly model the ash movements. These inputs might change with time as the eruption enters different phases. This implies tracking the ash movement as conditions change, and new satellite imagery comes in. Thus, ultimately, the eruption must be detectable, regardless of changing eruption source and meteorological conditions. Volcanic cloud recognition can be particularly challenging, especially when meteorological clouds are present, which is typically the case in the tropics. Given the fact that a large fraction of the eruptions in the world happen in a tropical environment, we have based an automated volcanic cloud recognition algorithm on the fact that meteorological clouds and volcanic clouds behave differently. As a result, the pattern definition algorithm detects and defines volcanic clouds as different object types from meteorological clouds on satellite imagery. Following detection and definition, the algorithm then estimates the area covered by the ash. The area is then analyzed with respect to a plume growth rate methodology to get estimation of the volumetric and mass growth with time. This way, we were able to get an estimation of the MER with time, as plume growth is dependent on MER. To test our approach, we used the examples of two eruptions of different source strength, in two different climatic regimes, and for which therefore the weather during the eruption was quite different: Manam (Papua New Guinea) January 27 2005, which produced a stratospheric umbrella cloud and was

  6. Eruption stage of permanent molars and occlusal caries activity/arrest.

    PubMed

    Alves, L S; Zenkner, J E A; Wagner, M B; Damé-Teixeira, N; Susin, C; Maltz, M

    2014-07-01

    This study assessed the association between the eruption stage of permanent second molars and occlusal caries activity among 12-year-old schoolchildren from South Brazil. A cross-sectional study was performed in Porto Alegre using a multistage probability sampling strategy to select a representative sample. Clinical examination was conducted to assess the eruption stage of permanent molars, Gingival Bleeding Index, and, after tooth cleaning and drying, caries experience (noncavitated and cavitated lesions, including caries activity assessment). Data were collected on sex, socioeconomic status, mother's education, brushing frequency, and consumption of soft drinks. Generalized estimating equations were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Overall, 983 schoolchildren with 3,071 second molars were available for analysis. Whereas active caries was observed in 6.6% of fully erupted permanent second molars, caries affected 26.2%, 29.6%, and 18.2% of erupting molars classified as stages 1, 2, and 3, respectively: stage 1, partially erupted occlusal surface; stage 2, fully erupted occlusal surface, <1/2 crown exposed; and stage 3, fully erupted occlusal surface, >1/2 crown exposed. After adjusting for socioeconomic and behavioral variables, partially erupted molars were significantly more likely to present active caries lesions than molars in full occlusion: stage 1, OR = 4.99 (95% CI = 3.38, 7.38); stage 2, OR = 5.18 (95% CI = 3.14, 8.53); stage 3, OR = 3.20 (95% CI = 2.21, 4.64). Similar results were found when clinical variables were included in the adjusted model. In conclusion, most occlusal caries lesions tend to arrest/revert when teeth reach the occlusal plan; however, an important proportion of these lesions remains active and in need of proper management. Children at risk should be targeted with preventive and minimally invasive strategies. © International & American Associations for Dental Research.

  7. Sub-glacial volcanic eruptions

    USGS Publications Warehouse

    White, Donald Edward

    1956-01-01

    The literature on sub-glacial volcanic eruptions and the related flood phenomena has been reviewed as a minor part of the larger problem of convective and conductive heat transfer from intrusive magma. (See Lovering, 1955, for a review of the extensive literature on this subject.) This summary of data on sub-glacial eruptions is part of a program that the U.S. Geological Survey is conducting in connection with its Investigations of Geologic Processes project on behalf of the Division of Research, U.S. Atomic Energy Commission.

  8. Widespread bullous fixed drug eruption.

    PubMed

    Patell, Rushad D; Dosi, Rupal V; Shah, Purav C; Joshi, Harshal S

    2014-02-07

    A 53-year-old man developed a widespread erythematous eruption which rapidly evolved into fluid-filled bulla mostly involving the distal areas of all four limbs and erosions on the oral as well as anogenital mucosa. Based on clinical presentation, chronology of drug exposure, past events and histopathology as diagnosis of widespread bullous fixed drug eruption was made over Steven Johnson-toxic epidermal necrolysis syndrome. Steroids were deferred and the lesions healed with minimal pigmentation within a week. Differentiating between the two entities has been historically difficult, and yet can have significant therapeutic and prognostic implications.

  9. Laser light passage through restored and carious posterior teeth.

    PubMed

    Chandler, N P; Pitt Ford, T R; Monteith, B D

    2014-08-01

    Laser Doppler flowmetry (LDF) has been used to investigate pulpal blood flow as a means of pulp vitality testing. Transmission of laser light from the tooth surface to the pulp space may be influenced by caries and restorations. One hundred and twenty-two first and second molars that had caries into dentine, restorations or significant loss of coronal tissue were sectioned in half axio-bucco-lingually. The two sections were illuminated with a laser from their buccal and lingual aspects 2 mm coronal to the amelocemental junction. Light reaching the pulp space was recorded. Buccal and lingual illumination sites were equally effective for 67 teeth (55%). Buccal sites alone were effective for 35 teeth (29%), despite over one-third of these surfaces being restored or featuring enamel or dentine caries. A lingual position alone was effective for 20 teeth (16%). Caries affected light transmission, but for over half the teeth, the pulp could be illuminated from all four probe positions. No effect was found when the influence of mesial and distal restorations on transmission into the corresponding tooth section was examined. The pulp spaces of most (84%) restored, and carious posterior teeth could be illuminated by laser light from their buccal aspect and these teeth could potentially be vitality tested using LDF. © 2014 John Wiley & Sons Ltd.

  10. Io - One of at Least Four Simultaneous Erupting Volcanic Eruptions

    NASA Technical Reports Server (NTRS)

    1979-01-01

    This photo of an active volcanic eruption on Jupiter's satellite Io was taken 1 hour, 52 minutes after the accompanying picture, late in the evening of March 4, 1979, Pacific time. On the limb of the satellite can be seen one of at least four simultaneous volcanic eruptions -- the first such activity ever observed on another celestial body. Seen against the limb are plume-like structures rising more than 60 miles (100 kilometers) above the surface. Several eruptions have been identified with volcanic structures on the surface of Io, which have also been identified by Voyager 1's infrared instrument as being abnormally hot -- several hundred degrees warmer than surrounding terrain. The fact that several eruptions appear to be occurring at the same time suggests that Io has the most active surface in the solar system and that volcanism is going on there essentially continuously. Another characteristic of the observed volcanism is that it appears to be extremely explosive, with velocities more than 2,000 miles an hour (at least 1 kilometer per second). That is more violent than terrestrial volcanoes like Etna, Vesuvius or Krakatoa.

  11. Do Fluoride Ions Protect Teeth?

    ERIC Educational Resources Information Center

    Parkin, Christopher

    1998-01-01

    Begins with the procedure and results from an investigation on the effect of fluoride on the reaction between eggshell (substitute teeth) and dilute ethanoic acid. Describes an elegantly modified and improvised apparatus. (DDR)

  12. Restoring primary anterior teeth.

    PubMed

    Waggoner, William F

    2002-01-01

    A variety of esthetic restorative materials are available for restoring primary incisors. Knowledge of the specific strengths, weakness, and properties of each material will enhance the clinician's ability to make the best choice of selection for each individual situation. Intracoronal restorations of primary teeth may utilize resin composites, glass ionomer cements, resin-modified ionomers, or polyacid-modified resins. Each has distinct advantages and disadvantages and the clinical conditions of placement may be a strong determining factor as to which material is utilized. Full coronal restoration of primary incisors may be indicated for a number of reasons. Crowns available for restoration of primary incisors include those that are directly bonded onto the tooth, which generally are a resin material, and those crowns that are luted onto the tooth and are some type of stainless steel crown. However, due to lack of supporting clinical data, none of the crowns can be said to be superior to the others under all circumstances. Though caries in the mandibular region is rare, restorative solutions for mandibular incisors are needed. Neither stainless steel crowns nor celluloid crown forms are made specifically for mandibular incisors. Many options exist to repair carious primary incisors, but there is insufficient controlled, clinical data to suggest that one type of restoration is superior to another. This does not discount the fact that dentists have been using many of these crowns for years with much success. Operator preferences, esthetic demands by parents, the child's behavior, and moisture and hemorrhage control are all variables which affect the decision and ultimate outcome of whatever restorative treatment is chosen.

  13. Mt. Etna Eruption

    NASA Technical Reports Server (NTRS)

    2002-01-01

    [figure removed for brevity, see original site] [figure removed for brevity, see original site] Figure 1: Vis/NIR Image CloseupFigure 2: Difference Image

    October 2002 Mt. Etna, a volcano on the island of Sicily, erupted on October 26, 2002. Preliminary analysis of data taken by the Atmospheric Infrared Sounder (AIRS) on NASA's Aqua satellite on October 28 shows the instrument can provide an excellent means to study the evolution and structure of the sulfur dioxide (SO2) plume emitted from volcanoes. These data also demonstrate that AIRS can be used to obtain the total mass of SO2 injected into the atmosphere during a volcanic event, information that may help us to better understand these dangerous natural occurrences in the future.

    This image was made from a sensor on the AIRS instrument that is sensitive to the visible and near-infrared portions of the spectrum. The visible/near infrared data show the smoke plume from Mt. Etna. The view is of Europe and the central Mediterranean with Italy in the center. Since the visible/near infrared sensor on AIRS is sensitive to wavelengths that are different than the human eye, vegetated regions appear red (compare the red color of Europe with the tan desert of North Africa in the lower left). Figure 1 is a closer view of Sicily and shows a long, brownish smoke plume extending across the Mediterranean to Africa. This is consistent with the enhanced feature in the difference image in Figure 2 and helps validate the information inferred from that image.

    Figure 2 clearly shows the SO2 plume. This image was created by comparing data taken at two different frequencies, or channels, and creating one image that highlights the differences between these two channels. Both channels are sensitive to water vapor, but one of the channels is also sensitive to SO2. By subtracting out the common water vapor signal in both channels, the SO2 feature remains and shows up as an enhancement in the difference image.

    The

  14. [Canal preparation of fluorotic teeth].

    PubMed

    Belkhir, M S; Benani, S; Ben Ghenaia, H; Bhouri, L

    1990-12-01

    This study compared the effectiveness of nine root-canal preparation techniques of fluorotic teeth. Seventy-three canal systems from 53 extracted human fluorotic teeth were instrumented. Pre-and postinstrumentation measurements were taken of the root canal systems in the cervical, middle and apical thirds; they proved the efficiency of the method using Rispi and Helifile. The results of this study were also extrapolated to the clinical situation.

  15. Web-based evaluation of experts' opinions on impacted maxillary canines forced eruption using CBCT

    PubMed Central

    Miresmaeili, Amirfarhang; Farhadian, Nasrin; Mollabashi, Vahid; Yousefi, Faezeh

    2015-01-01

    AIM: This study aims at examining the difficulty in performing forced eruption of impacted maxillary canines, using CBCT information and according to experienced orthodontist's opinion. The second aim was to find the most important factors related to this decision. METHODS: Based on a careful literature review on impacted maxillary canines, ten main factors were selected to assess difficulties associated with impacted teeth. Thirty six consecutive patients with 50 impacted maxillary canines were examined and variables were measured for each impacted tooth using Dolphin 3D software. Ten orthodontists assessed the radiographs of teeth and provided their opinion on the difficulty in bringing impacted teeth into occlusion named subjective degree of difficulty (SDD). The correlation established between mean SDD of each tooth and measured variables were analyzed by means of linear regression. RESULTS: Mean SDD was 6.45 ± 1.22 for all 50 teeth. Linear regression showed a high coefficient of correlation between mean SDD and age, dilacerations, vertical height, angulation and horizontal overlap (P < 0.05). CONCLUSION: To predict the difficulty of impacted maxillary canines forced eruption, according to the opinion of experienced orthodontists, the factors age, dilaceration, angulation, overlap and vertical distance from the occlusal plane are the most important variables. PMID:25992993

  16. Two Types of Magnetic Flux Cancellation in the Solar Eruption of 2007 May 20

    NASA Technical Reports Server (NTRS)

    Sterlin, Alphonse C.; Moore, Ronald L.; Mason, Helen

    2010-01-01

    We study a solar eruption of 2007 May 20, in an effort to understand the cause of the eruption's onset. The event produced a GOES class B6.7 flare peaking at 05:56 UT, while ejecting a surge/filament and producing a coronal mass ejection (CME). We examine several data sets, including H-alpha images from the Solar Optical Telescope (SOT) on Hinode, EUV images from TRACE, and line-of-sight magnetograms from SOHO/MDI. Flux cancelation occurs among two different sets of flux elements inside of the erupting active region: First, for several days prior to eruption, opposite-polarity sunspot groups inside the region move toward each other, leading to the cancelation of approximately 10^{21} Mx of flux over three days. Second, within hours prior to the eruption, positive-polarity moving magnetic features (MMFs) flowing out of the positive-flux spots at approximately 1 kilometer per second repeatedly cancel with field inside a patch of negative-polarity flux located north of the sunspots. The filament erupts as a surge whose base is rooted in the location where the MMF cancelation occurs, while during the eruption that filament flows out along the polarity inversion line between the converging spot groups. We conclude that a plausible scenario is that the converging spot fields brought the magnetic region to the brink of instability, and the MMF cancelation pushed the system "over the edge." triggering the eruption.

  17. [Injuries to the permanent teeth. Periodontal lesions].

    PubMed

    Vinckier, F; Declerck, D; Verhaeghe, V; Vanassche, K

    1998-01-01

    obtained, the tooth can be preserved for a long period. When progressive replacement resorption (ankylosis) develops, most teeth can remain in position for about 10 years. When inflammatory resorption develops, the tooth will be lost within a short time.

  18. Take Care of Your Child's Teeth

    MedlinePlus

    ... Sections The Basics Overview Tooth Decay Take Action! Brushing Tips Use Fluoride Fluoride Supplements Foods and Drinks Dental Checkups The Basics The Basics: Overview Your child’s first teeth, or baby teeth, are important. Baby teeth hold space for adult teeth. Taking ...

  19. Revascularization after cryopreservation and autotransplantation of immature and mature apicoectomized teeth.

    PubMed

    Laureys, W; Beele, H; Cornelissen, R; Dermaut, L

    2001-04-01

    Autotransplantation of immature teeth can have a success rate of almost 98% if the tooth is atraumatically transplanted from the donor site to a suitable acceptor site and the extraoral time is kept to a minimum. When the tooth cannot be transplanted immediately, cryopreservation and storage in a tooth bank offer new possibilities for autotransplantation. However, the effect of cryopreservation on the revascularization of transplanted teeth is still unknown. The purpose of this study was to examine revascularization in immature teeth that have an open apex and in mature teeth that have had the apex cut. The study was carried out on 16 teeth in 2 dogs; 8 teeth were removed and immediately transplanted to the contralateral position and 8 teeth were cryopreserved and transplanted 1 week later. The results show that: (1) teeth can revascularize after autotransplantation if the original pulp tissue is removed at the time of extraction, (2) there is no significant difference in the amount of revascularization between teeth stored in a tooth bank for 7 days and those immediately transplanted without freezing, and (3) there is no difference in the ingrowth of new pulpal tissue between mature apicoectomized teeth and immature teeth.

  20. Attitude and beliefs of some nurses in government hospitals in Ibadan, Nigeria to natal/neonatal teeth in infants.

    PubMed

    Bankole, O O; Oke, G A

    2013-09-01

    Eruption of the first deciduous teeth in children has shown much variation and occasionally may erupt prematurely at birth or within one month of life. Myths about natal/neonatal teeth abound in the Nigerian culture. Nurses are health care providers who are in constant close contact with patients and can be invaluable in helping to dispel these associated myths. However, to provide correct information they should be adequately equipped to do so. The aim of this study thus, was to assess the attitudes and beliefs of some nurses in Ibadan, Nigeria to natal/neonatal teeth in infants. A cross sectional survey was conducted among 380 nurses in the teaching, general and local government hospitals and clinics in Ibadan, Nigeria. Results revealed that 41.3% of the respondents would express shock and surprise if they assisted in delivering a baby with natal teeth. Half of the respondents (49.7%) felt that natal/neonatal teeth will be a great source of embarrassment to the family while a smaller proportion (11.8%), believed it was a curse (p = 0.01). On the advice the respondents would give to the mothers, more than a th (39.7%), would recommend immediate extraction of the teeth. A further 42 (11.1%) nurses were of the opinion that spiritual cleansing should be carried out prior to extraction. A greater proportion of the older nurses would advice immediate extraction of the teeth (p = 0.031). Regarding the perceived effect of natal/neonatal teeth on the children, (7.4%), (12.6%) and (29.2%) of the respondents believed that the children will behave strangely, will possess spiritual authority and be victims of stigmatization later in life respectively. This study has revealed that knowledge gaps about natal/neonatal teeth exist among the nurses in Ibadan, Nigeria. Health education programmes targeted at nurses are essential to correct these beliefs.

  1. ASTER Tracks Continuing Popocatepetl Eruption

    NASA Image and Video Library

    2012-04-27

    NASA Terra spacecraft shows Popocatepetl, the nearly 18.000-foot-high volcano about 40 miles southeast of Mexico City, continuing to spew water vapor, gas, ashes and glowing rocks from its latest eruption, which started in mid-April 2012.

  2. Mt Agung (Bali) Eruption Plumes

    Atmospheric Science Data Center

    2017-12-05

    ... 2017 (left) and calculated plume heights (right)   Volcanic eruptions can generate a significant amount of atmospheric aerosols ... at an altitude of 4.5-5 km. At this altitude, the direct (ash fall) and indirect (surface temperature) effects are likely to remain ...

  3. Did the Nabro volcanic eruption directly overshoot the tropopause?

    NASA Astrophysics Data System (ADS)

    Biondi, Riccardo; Steiner, Andrea K.; Kirchengast, Gottfried; Brenot, Hugues; Rieckh, Therese

    2015-04-01

    During the night of 12 to 13 June 2011 an explosive eruption occurred at the Nabro volcano located in Eritrea (13.4°N, 41.7°E). This has been recognized as the largest volcanic eruption since Pinatubo 1991, ejecting ash and sulfur dioxide (SO2) into the atmosphere, spreading over more than 60 degrees in latitude and more than 100 degrees in longitude within a few days and lasting for more than 15 days. While there is agreement on the fact that the eruptive mass reached the stratosphere, the processes bringing the cloud to the lower stratosphere are still much debated. For solving this issue we used about 300 atmospheric profiles from Global Positioning System (GPS) Radio Occultation (RO) observations and analyzed the pre-eruption conditions and the impact of the eruption itself on the tropospheric and stratospheric thermal structure. The GPS RO technique enables measurements of the atmospheric parameters in nearly any meteorological condition, with global coverage, high vertical resolution and high accuracy, making RO data well suited to study the thermodynamic structure of volcanic clouds and their impact on climate. In the Nabro area there are no ground based measurements that can be used for such kind of studies and, in the period of the eruption, there are no acquisitions by the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite. By analyzing the RO bending angle anomaly in the volcanic cloud area, we evaluated the cloud top altitude and compared it to the tropopause altitude (also derived from RO) in the same area. Moreover, we analyzed the RO temperature profiles before and after the eruption. Our results show that the volcanic cloud directly overshoot the tropopause and that the injected SO2 warmed the lower stratosphere in an area of about 10x10 degrees in latitude and longitude for 6 months, which is consistent with the effect found on a larger scale for the Pinatubo eruption in 1991. This study shows the capabilities

  4. Mirror imaging of impacted and supernumerary teeth in dizygotic twins: A case report.

    PubMed

    Cassetta, Michele; Altieri, Federica; Giordano, Alessandra

    2015-02-01

    Mesiodens is the most common type of supernumerary tooth found in the premaxilla. It might be discovered by the clinical examination by chance on a radiograph or as the cause of an unerupted maxillary central incisor. The genetic transmission of supernumerary and impacted teeth is poorly understood. Mirror imaging in twins has been reported frequently in relation to several unilateral dental anomalies including mesiodens. This phenomenon is the appearance of an asymmetrical feature or anomaly occurring on the right side of one twin but on the left side of the other twin. The event of mesiodens mirror imaging in monozygotic twins has been described in literature. This is the first reported case of mesiodens mirror images in dizygotic twins. The de-scribed mesiodens caused the eruption failure of maxillary permanent incisors. The super-numerary teeth were removed to facilitate the spontaneous eruption of the impacted perma-nent maxillary incisors. Studies related to supernumerary teeth can be useful to clinicians in the early diagnosis of this anomaly. Clinical and radiographic examinations provide a correct therapeutic approach. Key words:Supernumerary teeth, twins, dental development.

  5. Mirror imaging of impacted and supernumerary teeth in dizygotic twins: A case report

    PubMed Central

    Altieri, Federica; Giordano, Alessandra

    2015-01-01

    Background: Mesiodens is the most common type of supernumerary tooth found in the premaxilla. It might be discovered by the clinical examination by chance on a radiograph or as the cause of an unerupted maxillary central incisor. The genetic transmission of supernumerary and impacted teeth is poorly understood. Mirror imaging in twins has been reported frequently in relation to several unilateral dental anomalies including mesiodens. This phenomenon is the appearance of an asymmetrical feature or anomaly occurring on the right side of one twin but on the left side of the other twin. The event of mesiodens mirror imaging in monozygotic twins has been described in literature. Results: This is the first reported case of mesiodens mirror images in dizygotic twins. The de-scribed mesiodens caused the eruption failure of maxillary permanent incisors. The super-numerary teeth were removed to facilitate the spontaneous eruption of the impacted perma-nent maxillary incisors. Clinical Implications: Studies related to supernumerary teeth can be useful to clinicians in the early diagnosis of this anomaly. Clinical and radiographic examinations provide a correct therapeutic approach. Key words:Supernumerary teeth, twins, dental development. PMID:25810831

  6. Influence of oral health behavior and sociodemographic factors on remaining teeth in Korean adults

    PubMed Central

    Song, In-Seok; Han, Kyungdo; Choi, Yeon-Jo; Ryu, Jae-Jun; Park, Jun-Beom

    2016-01-01

    Abstract In this study, the number and location of remaining teeth were analyzed according to sociodemographic variables, anthropometric measurements, and oral health behavior patterns. The hypothesis was that the number and location of remaining teeth would be affected by oral health behavior and by sociodemographic factors, such as education levels, household income, and urban/rural residency. This nationwide cross-sectional study was performed with a total of 36,026 representative Korean adults aged 19 and older. The data were taken from the 2012–2012 Korea National Health and Nutrition Examination Survey. Men had, on average, significantly more remaining teeth than women did. Women brushed their teeth more often than men per day and were more likely to brush their teeth after meals. The participants with higher education levels or household income had significantly more remaining teeth; the number of daily tooth brushing was positively associated with the number of remaining teeth; urban residents had significantly more remaining teeth than rural residents; and elderly adults had fewer remaining teeth than younger adults had (all with P < 0.05). The participants were more likely to retain their incisors (especially their canines) for their entire lifetimes than do so for their molars. From the incisors to the second premolars, they had more mandibular teeth than maxillary teeth, but among molars, they had more maxillary teeth than mandibular teeth. Elementary graduates with low household income had fewer remaining teeth than did university graduates with high household income (P < 0.0001). Finally, participants with high socioeconomic status were more likely to lose their molar teeth than anterior teeth compared to those with low socioeconomic status. The participants who brushed their teeth fewer times per day, those with low household incomes and/or education levels, and those who lived in rural districts had significantly higher prevalence of tooth

  7. [Ancient teeth: research on teeth and jaws from archaeological sites].

    PubMed

    Jelsma, J

    2016-05-01

    Archaeology aims to enhance our understanding of the human past. An archaeologist devotes him- or herself to material remains, most often from the earth. The best sources of information about human behaviour and the earlier conditions of life for human beings are gravesites. In addition to being a source of cultural information, well-preserved skeletons offer vast possibilities for biochemical and genetic research. Teeth in particular can provide a treasure trove of information about the lives of our ancestors. With DNA analysis, gender and genetic relationships can be determined, however, the surface of the teeth also provides information about gender, age and genetic relationships and, of course, about the use of the teeth. New discoveries are being made and new (bio-)archaeological analyses are being carried out all the time.

  8. Cutaneous drug eruption induced by antihistamines.

    PubMed

    Viñas, M; Castillo, M J; Hernández, N; Ibero, M

    2014-12-01

    Topical application of antihistamines commonly leads to sensitization for patients, but systemic administration of antihistamines rarely induces allergic hypersensitivity, which is mainly linked to phenothiazine-derived and piperazine-derived compounds. We report a 70-year-old woman whose medical history included lichen planus, and who was referred by the dermatology department of our hospital for suspected allergy to corticosteroids. The reason for referral was that on the fourth day of treatment with prednisone and hydroxyzine, the patient presented a bilateral highly pruritic palmar erythema that evolved to a generalized morbilliform rash with subsequent complete desquamation. At a later time, she took cetirizine for a cold, and developed palmar erythema and desquamation. Skin tests (prick and intradermal tests) were performed with steroids, and patch tests (read after 48 and 96 h) with corticosteroids and antihistamines. Controlled oral challenge tests were performed with prednisone and with an alternative antihistamine. Skin tests were negative for all corticosteroids. Patch tests were negative for all corticosteroids, but the antihistamine test was positive for hydroxyzine. Oral challenge with prednisone and dexchlorpheniramine was negative. The patient was diagnosed with cutaneous drug eruption from hydroxyzine and cetirizine. We consider it is important to assess every patient whose skin condition worsens after treatment with antihistamines, especially hydroxyzine, because it is known that antihistamines are often not recognised as the culprit in cases of cutaneous eruption. © 2014 British Association of Dermatologists.

  9. Surgical removal versus retention for the management of asymptomatic impacted wisdom teeth.

    PubMed

    Mettes, Theodorus Dirk G; Ghaeminia, Hossein; Nienhuijs, Marloes E L; Perry, John; van der Sanden, Wil J M; Plasschaert, Alphons

    2012-06-13

    The prophylactic removal of asymptomatic impacted wisdom teeth is defined as the (surgical) removal of wisdom teeth in the absence of local disease. Impacted wisdom teeth may be associated with pathological changes, such as inflammation of the gums around the tooth, root resorption, gum and alveolar bone disease, damage to the adjacent teeth and the development of cysts and tumours. Other reasons to justify prophylactic removal have been to prevent late incisor crowding. When surgical removal is carried out in older patients, following the development of symptoms, the risk of postoperative complications, pain and discomfort increases. Nevertheless, in most developed countries prophylactic removal of trouble-free wisdom teeth, either impacted or fully erupted, has long been considered as 'appropriate care' and is a very common procedure. There is a need to determine whether there is evidence to support this practice. To evaluate the effects of prophylactic removal of asymptomatic impacted wisdom teeth in adolescents and adults compared with the retention (conservative management) of these wisdom teeth. The following electronic databases were searched: the Cochrane Oral Health Group's Trials Register (to 30 March 2012), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2012, Issue 1), MEDLINE via OVID (1950 to 30 March 2012), and EMBASE via OVID (1980 to 30 March 2012). There were no restrictions on language or date of publication. All randomised controlled trials (RCTs) on adolescents and adults comparing the effect of prophylactic removal of asymptomatic impacted wisdom teeth with no-treatment (retention). Six review authors screened the results of the search and assessed whether trials met the inclusion criteria for the review. Data extraction and risk of bias assessment were conducted in duplicate and independently by six review authors. Where information was unclear, authors of studies were contacted for additional information

  10. Tooth eruption: altered gene expression in the dental follicle of patients with cleidocranial dysplasia.

    PubMed

    Dorotheou, D; Gkantidis, N; Karamolegkou, M; Kalyvas, D; Kiliaridis, S; Kitraki, E

    2013-02-01

    The dental follicle plays an important role in tooth eruption by providing key regulators of osteogenesis and bone resorption. Patients with cleidocranial dysplasia (CCD) exhibit delayed tooth eruption in combination with increased bone density in the maxilla and mandible, suggesting disturbances in bone remodeling. The aim of this study was to determine the expression of genes relevant for tooth eruption and bone remodeling in the dental follicles of patients with CCD and normal subjects. Thirteen dental follicles were isolated from five unrelated patients with CCD, and fourteen dental follicles were obtained from 10 healthy individuals. All teeth were in the intraosseous phase of eruption. The expression of RANK, RANKL, OPG, and CSF-1 was determined by quantitative RT-PCR. In patients with CCD, the mRNA levels of RANK, OPG, and CSF-1 were significantly elevated compared with the control group. Accordingly, the ratios of RANKL/OPG and RANKL/RANK mRNAs were significantly decreased in patients with CCD. The observed alterations in the expression and ratios of the aforementioned factors in the dental follicle of CCD individuals suggest a disturbed paracrine signaling for bone remodeling that could be responsible for the impaired tooth eruption seen in these patients. © 2012 John Wiley & Sons A/S.

  11. Enamel thickness in primary teeth.

    PubMed

    Arangannal, Ponnudurai; Chandra, Biswaroop; Hariharan, V S; Vishnurekha; Jeevarathan; Vijayaprabha

    2012-01-01

    The aim of this study was to determine the enamel thickness of all primary teeth in both maxilla and mandible. An in vitro study was performed with fifty primary teeth including five each of central and lateral incisor, canine, first and second primary molars in both maxillary and mandibular region. Samples were mounted on wax sheets and scanned using a 64-slice CT scanner which were then 3D reconstructed. Three serial slices were obtained from the middle of the coronal portion of each tooth. Volume rendering was done to differentiate three distinct zones of enamel, dentin and the pulp from each slice. A box was constructed touching the borders of the image on all the surfaces and the mid-point of each side was taken to measure the enamel thickness. Tests used were ANOVA, Post-hoc Tukey's test and student's paired t-test. Enamel thickness was not the same on all the sides. Intergroup comparisons between maxillary anterior and posterior teeth showed difference in enamel thickness. On comparing the mandibular anterior and posterior teeth, the posteriors showed a greater value of enamel thickness on all the sides (p < 0.05). Primary enamel does not follow the same thickness patterns on all sides. It is also different in each primary tooth. There was an increase in enamel thickness in posterior teeth on comparison to their anterior counterparts in both maxilla and mandible. Enamel thickness was more on the distal aspect compared to mesial in all samples.

  12. Volcanic eruption volume flux estimations from very long period infrasound signals

    NASA Astrophysics Data System (ADS)

    Yamada, Taishi; Aoyama, Hiroshi; Nishimura, Takeshi; Iguchi, Masato; Hendrasto, Muhamad

    2017-01-01

    We examine very long period infrasonic signals accompanying volcanic eruptions near active vents at Lokon-Empung volcano in Indonesia, Aso, Kuchinoerabujima, and Kirishima volcanoes in Japan. The excitation of the very long period pulse is associated with an explosion, the emerging of an eruption column, and a pyroclastic density current. We model the excitation of the infrasound pulse, assuming a monopole source, to quantify the volume flux and cumulative volume of erupting material. The infrasound-derived volume flux and cumulative volume can be less than half of the video-derived results. A largely positive correlation can be seen between the infrasound-derived volume flux and the maximum eruption column height. Therefore, our result suggests that the analysis of very long period volcanic infrasound pulses can be helpful in estimating the maximum eruption column height.

  13. Nyiragongo Volcano before the Eruption

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Nyiragongo is an active stratovolcano situated on the Eastern African Rift; it is part of Africa's Virunga Volcanic Chain. In a massive eruption that occurred on January 17, 2002, Nyiragongo sent a vast plume of smoke and ash skyward, and three swifly-moving rivers of lava streaming down its western and eastern flanks. Previous lava flows from Nyiragongo have been observed moving at speeds of up to 40 miles per hour (60 kph). The lava flows from the January 17 eruption destroyed more than 14 villages in the surrounding countryside, forcing tens of thousands to flee into the neighboring country of Rwanda. Within one day the lava ran to the city of Goma, situated on the northern shore of Lake Kivu about 12 miles (19 km) south of Nyiragongo. The lava cut a 200 foot (60 meter) wide swath right through Goma, setting off many fires, as it ran into Lake Kivu. Goma, the most heavily populated city in eastern Democratic Republic of Congo, is home to about 400,000 people. Most of these citizens were forced to flee, while many have begun to return to their homes only to find their homes destroyed. This true-color scene was captured by the Enhanced Thematic Mapper Plus (ETM+), flying aboard the Landsat 7 satellite, on December 11, 2001, just over a month before the most recent eruption. Nyiragongo's large crater is clearly visible in the image. As recently as June 1994, there was a large lava lake in the volcano's crater which had since solidified. The larger Nyamuragira Volcano is located roughly 13 miles (21 km) to the north of Nyiragongo. Nyamuragira last erupted in February and March 2001. That eruption was also marked by columns of erupted ash and long fluid lava flows, some of which are apparent in the image as dark greyish swaths radiating away from Nyamuragira. Both peaks are also notorious for releasing large amounts of sulfur dioxide, which presents another health hazard to people and animals living in close proximity. Image by Robert Simmon, based on data supplied

  14. Marsupialization of a large dentigerous cyst in the mandible with orthodontic extrusion of three impacted teeth. A case report

    PubMed Central

    Abbasi, Arshad

    2017-01-01

    The dentigerous cyst (DC) is the most common type of developmental odontogenic cyst. It is usually asymptomatic and associated with the crown of an unerupted or impacted tooth. However, after a long duration, it is likely to cause significant bone resorption, cortical expansion, and tooth displacement. This report presents a large infected DC in the mandible of a 12-year-old female patient. The DC was located inferior to badly decayed primary molars and surrounded three impacted permanent teeth: canine, first premolar, which had a dilacerated root, and second premolar. The DC was treated successfully by marsupialization and extrusion of the impacted teeth. In conclusion, the combination of marsupialization with orthodontic extrusion is a conservative, efficient protocol that stimulates bone healing and promotes the eruption of cyst-associated teeth even if they are deeply impacted, crowded, or have a dilacerated root. Key words:Dentigerous cyst, marsupialization, impacted teeth, orthodontic extrusion, dilacerated root. PMID:29075422

  15. Restoration of endodontically treated teeth.

    PubMed

    Mannocci, F; Cowie, J

    2014-03-01

    The restoration of endodontically treated teeth has undergone significant changes in the last 20 years. Most of these changes are associated with the preservation of tooth structure, this has been achieved first of all with the increasing use of operative microscopes, nickel titanium instruments and more recently cone beam computed tomography; these instruments have allowed the clinicians to reduce significantly the amount of coronal and radicular hard tooth tissue removed in the process of cutting access cavities. The use of composites has also allowed the clinicians to restore with adhesive techniques teeth that would otherwise require extensive and destructive mechanical retentions. The use of partial crowns is becoming increasingly popular and this also helps prevent tooth structure loss. This article will focus on the choices available to restore both anterior and posterior teeth and will focus more on these contemporary adhesive techniques.

  16. The retrieval of unerupted teeth in pedodontics: two case reports

    PubMed Central

    2014-01-01

    Introduction The retrieval of unerupted teeth in pedodontics is always significant to preserve the trophism of adjacent tissues, establish the correct space, provide adequate function and maintain good esthetics for the patient. The treatment plan is based on radiographic examinations and measurements, and on an accurate clinical evaluation; it aims to achieve the best treatment possible depending on the complexity of the specific case. In the most difficult clinical cases it is very important to have an early diagnosis, which is essential to plan the treatment and achieve success. In these cases, the pediatrician is in a strategic position to give an early diagnosis through a child’s medical history and by counting the child’s teeth. Case presentation This article presents two different difficult clinical cases of impacted teeth diagnosed during pediatric age, with a radiological analysis, and successfully treated with orthodontic devices designed for these specific cases. Clinical case 1 describes a 13-year-old Italian girl; clinical case 2 describes a 9-year-old Italian girl. The use of these devices achieved the desired treatment goals. The problems associated with impacted teeth and the biomechanical interventions used for these patients are discussed. Conclusions An early and careful diagnosis followed by an accurate treatment plan for the individual cases can lead to retrieval of the impacted teeth without affecting other anatomic structures and adjacent teeth. In these cases, the pediatrician is in a strategic position to give an early diagnosis through a child’s medical history and by counting the child’s teeth. PMID:25301242

  17. Chilean Volcanic Eruption Nighttime View

    NASA Image and Video Library

    2015-04-27

    The April 18, 2015 eruption of Calbuco Volcano in Chile, as seen by NASA Terra spacecraft, led to the evacuation of thousands of citizens near the summit, blanketed nearby towns with a layer of ash, and disrupted air traffic. One week later, on April 26, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument on NASA's Terra spacecraft acquired this nighttime thermal infrared image of Calbuco. Hot eruptive material at the summit appears in white (hot), with a purple plume streaming to the right, indicating that it is ash-laden. The image covers an area of 3.1 by 4.1 miles (5 by 6.6 kilometers), and is located at 41.3 degrees south, 72.5 degrees west. http://photojournal.jpl.nasa.gov/catalog/PIA19382

  18. Volcanic eruption detection with TOMS

    NASA Technical Reports Server (NTRS)

    Krueger, Arlin J.

    1987-01-01

    The Nimbus 7 Total Ozone Mapping Spectrometer (TOMS) is designed for mapping of the atmospheric ozone distribution. Absorption by sulfur dioxide at the same ultraviolet spectral wavelengths makes it possible to observe and resolve the size of volcanic clouds. The sulfur dioxide absorption is discriminated from ozone and water clouds in the data processing by their spectral signatures. Thus, the sulfur dioxide can serve as a tracer which appears in volcanic eruption clouds because it is not present in other clouds. The detection limit with TOMS is close to the theoretical limit due to telemetry signal quantization of 1000 metric tons (5-sigma threshold) within the instrument field of view (50 by 50 km near the nadir). Requirements concerning the use of TOMS in detection of eruptions, geochemical cycles, and volcanic climatic effects are discussed.

  19. Volcanic eruptions and solar activity

    NASA Technical Reports Server (NTRS)

    Stothers, Richard B.

    1989-01-01

    The historical record of large volcanic eruptions from 1500 to 1980 is subjected to detailed time series analysis. In two weak but probably statistically significant periodicities of about 11 and 80 yr, the frequency of volcanic eruptions increases (decreases) slightly around the times of solar minimum (maximum). Time series analysis of the volcanogenic acidities in a deep ice core from Greenland reveals several very long periods ranging from about 80 to about 350 yr which are similar to the very slow solar cycles previously detected in auroral and C-14 records. Solar flares may cause changes in atmospheric circulation patterns that abruptly alter the earth's spin. The resulting jolt probably triggers small earthquakes which affect volcanism.

  20. Multiple essential MT1-MMP functions in tooth root formation, dentinogenesis, and tooth eruption

    PubMed Central

    Wimer, H.F.; Yamada, S.S.; Yang, T.; Holmbeck, K.; Foster, B.L.

    2016-01-01

    Membrane-type matrix metalloproteinase 1 (MT1-MMP) is a transmembrane zinc-endopeptidase that breaks down extracellular matrix components, including several collagens, during tissue development and physiological remodeling. MT1-MMP-deficient mice (MT1-MMP−/−) feature severe defects in connective tissues, such as impaired growth, osteopenia, fibrosis, and conspicuous loss of molar tooth eruption and root formation. In order to define the functions of MT1-MMP during root formation and tooth eruption, we analyzed the development of teeth and surrounding tissues in the absence of MT1-MMP. In situ hybridization showed that MT1-MMP was widely expressed in cells associated with teeth and surrounding connective tissues during development. Multiple defects in dentoalveolar tissues were associated with loss of MT1-MMP. Root formation was inhibited by defective structure and function of Hertwig's epithelial root sheath (HERS). However, no defect was found in creation of the eruption pathway, suggesting that tooth eruption was hampered by lack of alveolar bone modeling/remodeling coincident with reduced periodontal ligament (PDL) formation and integration with the alveolar bone. Additionally, we identified a significant defect in dentin formation and mineralization associated with the loss of MT1-MMP. To segregate these multiple defects and trace their cellular origin, conditional ablation of MT1-MMP was performed in epithelia and mesenchyme. Mice featuring selective loss of MT1-MMP activity in the epithelium were indistinguishable from wild type mice, and importantly, featured a normal HERS structure and molar eruption. In contrast, selective knock-out of MT1-MMP in Osterix-expressing mesenchymal cells, including osteoblasts and odontoblasts, recapitulated major defects from the global knock-out including altered HERS structure, short roots, defective dentin formation and mineralization, and reduced alveolar bone formation, although molars were able to erupt. These data

  1. The Influence of Eruptive Fluid Pressure and Vent Radius on the Eruption Style of High- Pressure Supersonic Volcanoes

    NASA Astrophysics Data System (ADS)

    Ogden, D. E.; Wohletz, K. H.; Brodsky, E. E.; Glatzmaier, G. A.

    2006-12-01

    Through observations, experiments, and modeling much has been learned about the effects of fluid pressure and vent radius on the dynamics of large, explosive volcanic eruptions. The standard semi-analytic model suggests that increasing radius results in less stable columns while the effect of overpressure is neglected by simply assuming a choked flow condition at the base of the thermal plume or a shock-free compressible flow (A.W. Woods, Rev. Geophys. v33, 1995). However, the standing shock waves that may develop in high- pressure supersonic volcanic eruptions complicate the connection between the fluid dynamics of the conduit and the stability of the buoyant plume, and in some cases can result in the inverse dependencies. The strength and position of these standing shock waves (and therefore their effect on energies and column collapse) are dependent on a number of factors including eruptive fluid pressure and vent radius. Here, using computational simulations, we examine the influence of these two parameters on the energy supplied to a buoyant column from a supersonic vent. We use a pseudogas approximation for a rhyolitic ash-gas composite flow to show that increasing the overpressure results in wider plumes at the top of the gas thrust region with slower interior velocities. This effect can be significant at overpressure ratios as low as 10. Since a 1 km deep magma chamber at lithostatic pressure results in an overpressure ratio of 300, most moderate to large eruptions will be affected by the shocks and therefore will likely have these inverse dependencies. For instance, estimates for overpressure at the vent based on petrological evidence and conduit models for many explosive eruptions (e.g. the 1991 eruption of Mt. Pinatubo) are of the same order of magnitude as the overpressure ratio in our strongly affected simulations. By combining the results from our simulations with values of overpressures and vent radii from petrologic and field methods, we constrain

  2. The 1883 eruption of Krakatau

    NASA Technical Reports Server (NTRS)

    Self, S.; Rampino, M. R.

    1981-01-01

    The 1883 eruption of Krakatau was a modest ignimbrite-forming event. The deposits are primarily coarse-grained dacitic, non-welded ignimbrite. Large explosions produced pyroclastic flows that entered the sea, generating destructive tsunami. Grain-size studies of the ignimbrite suggest that these explosions were not driven by magma-seawater interaction. The total bulk volume of pyroclastic deposits, including co-ignimbrite ash, is estimated to be 18-21 cu km.

  3. Medical effects of volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Baxter, Peter J.

    1990-09-01

    Excluding famine and tsunamis, most deaths in volcanic eruptions have been from pyroclastic flows and surges (nuées ardentes) and wet debris flows (lahars). Information on the causes of death and injury in eruptions is sparse but the available literature is summarised for the benefit of volcanologists and emergency planners. In nuées, thermal injury may be at least as important as asphyxia in causing immediate deaths. The high temperature of the gases and entrained particles readily causes severe burns to the skin and the air passages and the presence of both types of injury in an individual may combine to increase the delayed mortality risk from respiratory complications or from infection of burns. Trauma from missiles or body displacement is also common, but the role of asphyxiant or irritant gases, and steam, remains unclear. The ratio of dead: injured is much higher than in other natural disasters. At the periphery of a nuée being protected inside buildings which remain intact appears to greatly increase the chances of survival. In lahars, infected wounds and crush injury are the main delayed causes of death, and the scope for preventive measures, other than evacuation, is small. The evidence from Mount St. Helens, 1980, and other major eruptions indicates that, although mortality is high within the main zone of devastation and in the open, emergency planning should concentrate on the periphery of a nuée where preventive measures are feasible and could save many lives in densely populated areas.

  4. Observed Aspects of Reconnection in Solar Eruptions

    NASA Astrophysics Data System (ADS)

    Moore, Ronald L.; Sterling, Alphonse C.; Gary, G. Allen; Cirtain, Jonathan W.; Falconer, David A.

    2011-10-01

    The observed magnetic field configuration and signatures of reconnection in the large solar magnetic eruptions that make major flares and coronal mass ejections and in the much smaller magnetic eruptions that make X-ray jets are illustrated with cartoons and representative observed eruptions. The main reconnection signatures considered are the imaged bright emission from the heated plasma on reconnected field lines. In any of these eruptions, large or small, the magnetic field that drives the eruption and/or that drives the buildup to the eruption is initially a closed bipolar arcade. From the form and configuration of the magnetic field in and around the driving arcade and from the development of the reconnection signatures in coordination with the eruption, we infer that (1) at the onset of reconnection the reconnection current sheet is small compared to the driving arcade, and (2) the current sheet can grow to the size of the driving arcade only after reconnection starts and the unleashed erupting field dynamically forces the current sheet to grow much larger, building it up faster than the reconnection can tear it down. We conjecture that the fundamental reason the quasi-static pre-eruption field is prohibited from having a large current sheet is that the magnetic pressure is much greater than the plasma pressure in the chromosphere and low corona in eruptive solar magnetic fields.

  5. Are Plinian type eruptions possible on Venus?

    NASA Technical Reports Server (NTRS)

    Sugita, Seiji; Matsui, Takafumi

    1993-01-01

    Calculations of dynamics of eruption plumes in the Venusian atmosphere reveal the following results: (1) conditions for a convective eruption column are very limited on Venus with required magma temperatures higher than 1100 K; otherwise pyroclastic flows form; (2) once a convective eruption column is established, it may extend as high as about the tropopause (approximately 60 km); and (3) critical eruption velocities for a convective eruption column as a function of temperature and gas content of magma may provide a useful tool for estimating interior condition of Venus, including its volatile inventory. Volcanism is a major process to transport volatile from mantle of a planet to its surface (degassing) as well as heat and mass, all of which affect planetary evolution. For example, after completion of planetary accretion, volcanism is the dominant continuous degassing process for all the terrestrial planets. Explosive volcanism is a very important process for mantle degassing due to its high magma gas content. Consequently, eruption styles and the controlling physical processes need to be understood. Recent satellite and terrestrial ground-based observations suggest existence of explosive volcanism on Venus even though explosive volcanism is very difficult to occur on Venus due to its high atmospheric pressure. The purpose is to investigate dynamics of explosive eruption on Venus and the relation between eruption conditions such as gas content and temperature of magma and eruption velocity, and eruption styles such as Plinian type and pyroclastic flow type.

  6. Interventions for treating asymptomatic impacted wisdom teeth in adolescents and adults.

    PubMed

    Mettes, T G; Nienhuijs, M E L; van der Sanden, W J M; Verdonschot, E H; Plasschaert, A J M

    2005-04-18

    The prophylactic removal of asymptomatic impacted wisdom teeth is defined as the (surgical) removal of wisdom teeth in the absence of local disease. Impacted wisdom teeth have been associated with pathological changes, such as inflammation of the gums around the tooth, root resorption, gums- and alveolar bone disease, damage of the adjacent teeth, the development of cysts and tumours. Several other reasons to justify prophylactic removal have also been given. Wisdom teeth do not always fulfil a functional role in the mouth. When surgical removal is carried out in older patients the risk of more postoperative complications, pain and discomfort increases. Nevertheless, in most developed countries the prophylactic removal of trouble-free wisdom teeth, either impacted or fully erupted, has long been considered as 'appropriate care'. Prudent decision-making, with adherence to specified indicators for removal, may reduce the number of surgical procedures by 60% or more. It has been suggested that watchful monitoring of asymptomatic wisdom teeth may be an appropriate strategy. To evaluate the effect of prophylactic removal of asymptomatic impacted wisdom teeth in adolescents and adults compared with the retention of these wisdom teeth. The following electronic databases were searched:The Cochrane Oral Health Group Trials Register (4 August 2004), the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (1966 to 4 August 2004), PubMed (1966 to 4 August 2004), EMBASE (1974 to 4 August 2004). There was no restriction on language. Key journals were handsearched. An attempt was made to identify ongoing and unpublished trials. All randomised or controlled clinical trials (RCTs/CCTs) comparing the effect of prophylactic removal of asymptomatic impacted wisdom teeth with no-treatment (retention). Assessment of relevance, validity and data extraction were conducted in duplicate and independently by three reviewers. Where uncertainty existed, authors were contacted for

  7. Driving Solar Eruptions via Helicity Condensation

    NASA Astrophysics Data System (ADS)

    Dahlin, Joel Timothy; Antiochos, Spiro K.; DeVore, C. Richard

    2017-08-01

    One of the important questions in solar physics is, “How does the Sun store and release energy in coronal mass ejections"? Key to answering this question is understanding how the sun (a) stores magnetic energy in the form of a solar filament and (b) suddenly releases this energy as a coronal mass ejection. An important model for the energy release is the ‘magnetic breakout’ - a positive-feedback mechanism between filament ejection and magnetic reconnection. Recent theory and numerical calculations have demonstrated that helicity injected into the corona via photospheric driving can accumulate in the form of a filament channel of strongly sheared magnetic fields that can provide the free energy for a coronal mass ejection. We present preliminary calculations that, for the first time, incorporate helicity injection in a breakout topology to model a fully self-consistent eruption, from filament formation to ejection.

  8. Keeping Your Child's Teeth Healthy

    MedlinePlus

    ... oral disease — dental cavities (also called dental caries). How Can We Prevent Cavities? Cavities happen when bacteria and food left on the teeth after eating are not brushed away. Acid collects on a tooth, softening its enamel until ... Here's how to keep cavities away: Start good oral habits ...

  9. Forces in Erupting Flux Ropes: CMEs and Failed Eruptions

    NASA Astrophysics Data System (ADS)

    Chen, James

    2016-05-01

    A range of dynamical behaviors that can be exhibited by a quasi-statically evolving flux rope is studied. Starting with a CME-like flux rope in equilibrium balanced by the ambient coronal pressure (non-force-free) and an overlying coronal magnetic field (Bc), the poloidal flux is slowly increased, on a timescale much longer than the eruptive timescale of several to tens of minutes. In this configuration, the overlying field Bc provides an external downward restraining force, constituting an effective potential barrier. Slowly increasing poloidal flux causes the flux rope to gradually rise, following a sequence of quasi-static equilibria. As the apex of the flux rope rises past a critical height Z*, slightly higher than the peak of the potential barrier Bc(Z), it expands on a faster, dynamical (Alfvenic) timescale determined by the magnetic field and geometry of the flux rope. The expanding flux rope may reach a new equilibrium at height Z1. Observationally, this behavior would be recognized as a ``failed eruption.'' The new equilibrium flux rope is established if the magnetic tension force due to the toroidal magnetic field component Bt can balance the outward hoop force due to the poloidal component Bp. The flux rope may also expand without reaching a new equilibrium, provided a sufficiennt amount of poloidal flux is injected on a dynamical timescale so that the tension force cannot balance the hoop force. This scenario would result in a CME eruption. The influence of the poloidal flux injection, the Bc(Z) profile, and boundary conditions on the quantitative balance of the forces in an expanding flux rope is elucidated. Potentially observable consequences of the difference scenarios/models are discussed.Work supported by the Naval Research Laboratory Base Research Program

  10. Eruption Forecasting in Alaska: A Retrospective and Test of the Distal VT Model

    NASA Astrophysics Data System (ADS)

    Prejean, S. G.; Pesicek, J. D.; Wellik, J.; Cameron, C.; White, R. A.; McCausland, W. A.; Buurman, H.

    2015-12-01

    United States volcano observatories have successfully forecast most significant US eruptions in the past decade. However, eruptions of some volcanoes remain stubbornly difficult to forecast effectively using seismic data alone. The Alaska Volcano Observatory (AVO) has responded to 28 eruptions from 10 volcanoes since 2005. Eruptions that were not forecast include those of frequently active volcanoes with basaltic-andesite magmas, like Pavlof, Veniaminof, and Okmok volcanoes. In this study we quantify the success rate of eruption forecasting in Alaska and explore common characteristics of eruptions not forecast. In an effort to improve future forecasts, we re-examine seismic data from eruptions and known intrusive episodes in Alaska to test the effectiveness of the distal VT model commonly employed by the USGS-USAID Volcano Disaster Assistance Program (VDAP). In the distal VT model, anomalous brittle failure or volcano-tectonic (VT) earthquake swarms in the shallow crust surrounding the volcano occur as a secondary response to crustal strain induced by magma intrusion. Because the Aleutian volcanic arc is among the most seismically active regions on Earth, distinguishing distal VT earthquake swarms for eruption forecasting purposes from tectonic seismicity unrelated to volcanic processes poses a distinct challenge. In this study, we use a modified beta-statistic to identify pre-eruptive distal VT swarms and establish their statistical significance with respect to long-term background seismicity. This analysis allows us to explore the general applicability of the distal VT model and quantify the likelihood of encountering false positives in eruption forecasting using this model alone.

  11. Ozone depletion following future volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Eric Klobas, J.; Wilmouth, David M.; Weisenstein, Debra K.; Anderson, James G.; Salawitch, Ross J.

    2017-07-01

    While explosive volcanic eruptions cause ozone loss in the current atmosphere due to an enhancement in the availability of reactive chlorine following the stratospheric injection of sulfur, future eruptions are expected to increase total column ozone as halogen loading approaches preindustrial levels. The timing of this shift in the impact of major volcanic eruptions on the thickness of the ozone layer is poorly known. Modeling four possible climate futures, we show that scenarios with the smallest increase in greenhouse gas concentrations lead to the greatest risk to ozone from heterogeneous chemical processing following future eruptions. We also show that the presence in the stratosphere of bromine from natural, very short-lived biogenic compounds is critically important for determining whether future eruptions will lead to ozone depletion. If volcanic eruptions inject hydrogen halides into the stratosphere, an effect not considered in current ozone assessments, potentially profound reductions in column ozone would result.

  12. Response of the Indian Ocean Dipole to tropical volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Izumo, Takeshi; Khodri, Myriam; Vialard, Jérome; Lengaigne, Matthieu; Cassou, Christophe; Suresh, Iyyappan

    2017-04-01

    Large tropical explosive volcanic eruptions, such as Pinatubo in June 1991, emit stratospheric aerosols that backscatter shortwave radiation and cool earth's surface. The impacts of explosive volcanism on the highly-populated, climate-sensitive Indian Ocean region, in particular on its dominant climate mode, the Indian Ocean Dipole (IOD), however remain unclear. Here, we show that volcanism significantly forces a negative IOD-like oceanic response, using the CMIP database and dedicated experiments with a climate model forced by a Pinatubo-like eruption. In the first boreal fall after the eruption, such eruptions induce a spatially-variable cooling of the Indian Ocean. The cooling is stronger in the Northwest than in the Southeast Indian Ocean because of climatologically clearer skies. The resulting zonal SST gradient favors equatorial westerlies, which drive a typical negative IOD-like subsurface response (anomalously shallow/deep thermocline in the west/east with a consistent impact on primary production in CMIP5 models). The possible mechanisms of such response, and of its possible amplification through IOD positive coupled feedbacks, are quantified through a hierarchy of atmosphere and ocean numerical experiments. Improving current models (and their volcanic observations/assimilation systems), that agree qualitatively but not quantitatively on this volcanically-induced oceanic negative IOD, should lead to precious added skill for climate/ocean seasonal forecasting.

  13. Current Sheet Properties and Dynamics During Sympathetic Breakout Eruptions

    NASA Astrophysics Data System (ADS)

    Lynch, B. J.; Edmondson, J. K.

    2013-12-01

    We present the continued analysis of the high-resolution 2.5D MHD simulations of sympathetic magnetic breakout eruptions from a pseudostreamer source region. We examine the generation of X- and O-type null points during the current sheet tearing and track the magnetic island formation and evolution during periods of reconnection. The magnetic breakout eruption scenario forms an overlying 'breakout' current sheet that evolves slowly and removes restraining flux from above the sheared field core that will eventually become the center of the erupting flux rope-like structure. The runaway expansion from the expansion-breakout reconnection positive feedback enables the formation of the second, vertical/radial current sheet underneath the rising sheared field core as in the standard CHSKP eruptive flare scenario. We will examine the flux transfer rates through the breakout and flare current sheets and compare the properties of the field and plasma inflows into the current sheets and the reconnection jet outflows into the flare loops and flux rope ejecta.

  14. European climate response to tropical volcanic eruptions over the last half millennium

    NASA Astrophysics Data System (ADS)

    Fischer, E. M.; Luterbacher, J.; Zorita, E.; Tett, S. F. B.; Casty, C.; Wanner, H.

    2007-03-01

    We analyse the winter and summer climatic signal following 15 major tropical volcanic eruptions over the last half millennium based on multi-proxy reconstructions for Europe. During the first and second post-eruption years we find significant continental scale summer cooling and somewhat drier conditions over Central Europe. In the Northern Hemispheric winter the volcanic forcing induces an atmospheric circulation response that significantly follows a positive NAO state connected with a significant overall warm anomaly and wetter conditions over Northern Europe. Our findings compare well with GCM studies as well as observational studies, which mainly cover the substantially shorter instrumental period and thus include a limited set of major eruptions.

  15. Thermographic analysis of surface damage in teeth

    NASA Astrophysics Data System (ADS)

    Conde-Contreras, M.; Bante-Guerra, J.; Hernandez-Garcia, E.; Hernandez, A. M.; Trujillo, S.; Quintana, P.; Alvarado-Gil, J. J.

    2008-02-01

    The analysis of the surface of teeth is an important field of research and technological development due to the importance of dental pieces in health and aesthetics. The presence of cracks as well as the etching effects on teeth surface, due to different chemical agents, affects not only the appearance of teeth but its integrity. In this work, laser thermography analysis of dental pieces with damage in the form of cracks is presented. The technique consists in the illumination of the surface at the center of the sample, using a 300 mW pulsed solid state laser beam focused with a gradium lens, and monitoring the spatial and temporal distribution of the temperature field. The heating of the sample is monitored using a focal plane array infrared camera, sensitive in the spectral range 7.5-13 μm with a noise equivalent temperature difference of 0.12°C. The data acquisition was performed by the PC firewire port using a PCI-8254R card and a home-made program in Labview 8.0 was used for data acquisition. The images were processed in a home-made linux program to obtain the experimental table values. Our results are compared with position and frequency scans obtained by infrared photothermal radiometry. It is shown that the crack in the tooth appears as an increase in the photothermal signal. In contrast, the thermographic image shows a more detailed structure in which close to the crack the temperature increases, but at the crack the signal falls.

  16. How and Why Do Geysers Erupt?

    NASA Astrophysics Data System (ADS)

    Manga, M.

    2014-12-01

    Geysers are features that produce episodic eruptions of water, steam and sometimes non-condensable gases. Natural geysers are rare, with fewer than 1,000 worldwide. They are more than curiosities and popular tourist attractions: they offer a direct window into geothermal processes, and may serve as a natural small-scale laboratory to study larger-scale eruptive process such as those at volcanoes, and other self-organized, intermittent processes that result from phase separation and localized input of energy and mass. Despite > 200 years of scientific study, basic questions remain: Do eruptions begin from the bottom or top of the geyser? What controls eruption duration? Why do eruptions end? What are the required special subsurface geometries? Why are some geysers periodic, and others irregular? How and why do they respond to external influences such as weather, tides, and earthquakes? This presentation will review new insights from field studies at Lone Star geyser, Yellowstone National Park, geysers in the El Tatio geyser field, Chile, and laboratory models. At Lone Star we infer that dynamics are controlled by thermal and mechanical coupling between the conduit and a deeper, laterally-offset reservoir (called a "bubble trap" in previous studies). At El Tatio, we measured pressure and temperature within geysers over multiple eruption cycles: this data document the heating of liquid water by steam delivered from below. The laboratory experiments reveal how episodic release of steam from a bubble trap prepares a conduit for eruption and can generate a range of eruption intensities. In all cases, the eruption initiation, duration and termination are controlled by the interaction between the accumulation and transport of steam and liquid, and modulated by the geometry of the geyser's plumbing. Time series of thousands of eruptions confirm that internal processes control eruptions, with only pool geysers showing a sensitivity to air temperature; only very large stress

  17. Flux Cancellation Leading to CME Filament Eruptions

    NASA Technical Reports Server (NTRS)

    Popescu, Roxana M.; Panesar, Navdeep K.; Sterling, Alphonse C.; Moore, Ronald L.

    2016-01-01

    Solar filaments are strands of relatively cool, dense plasma magnetically suspended in the lower density hotter solar corona. They trace magnetic polarity inversion lines (PILs) in the photosphere below, and are supported against gravity at heights of up to approx.100 Mm above the chromosphere by the magnetic field in and around them. This field erupts when it is rendered unstable, often by magnetic flux cancellation or emergence at or near the PIL. We have studied the evolution of photospheric magnetic flux leading to ten observed filament eruptions. Specifically, we look for gradual magnetic changes in the neighborhood of the PIL prior to and during eruption. We use Extreme Ultraviolet (EUV) images from the Atmospheric Imaging Assembly (AIA), and magnetograms from the Helioseismic and Magnetic Imager (HMI), both on board the Solar Dynamics Observatory (SDO), to study filament eruptions and their photospheric magnetic fields. We examine whether flux cancellation or/and emergence leads to filament eruptions. We find that continuous flux cancellation was present at the PIL for many hours prior to each eruption. We present two CME-producing eruptions in detail and find the following: (a) the pre-eruption filament-holding core field is highly sheared and appears in the shape of a sigmoid above the PIL; (b) at the start of the eruption the opposite arms of the sigmoid reconnect in the middle above the site of (tether-cutting) flux cancellation at the PIL; (c) the filaments first show a slow-rise, followed by a fast-rise as they erupt. We conclude that these two filament eruptions result from flux cancellation in the middle of the sheared field, and thereafter evolve in agreement with the standard model for a CME/flare filament eruption from a closed bipolar magnetic field [flux cancellation (van Ballegooijen and Martens 1989 and Moore and Roumelrotis 1992) and runaway tether-cutting (Moore et. al 2001)].

  18. Knowledge of consequences of missing teeth in patients attending prosthetic clinic in u.C.h. Ibadan.

    PubMed

    Dosumu, O O; Ogunrinde, J T; Bamigboye, S A

    2014-06-01

    Various causes of tooth loss such as caries, trauma, periodontal diseases, and cancer have been documented in the literature. In addition, factors that can modify these causes such as level of education, age and sex have been studied. There is however paucity of information on whether patients or people with missing teeth are aware of the side effects of tooth loss on them or on the remaining teeth. This study investigated the knowledge of consequences of missing teeth among partially edentulous patients in a teaching hospital. Self-administered questionnaires were distributed to the patients to collect information relating to demography, cause and duration of tooth loss, awareness of the consequences of tooth loss and their sources of information. Four clinical conditions including supra-eruption, mastication, teeth drifting, and facial collapse were used to assess the level of awareness of consequences of missing teeth. Two hundred and three participants were included in the study. Their mean age was 45.5±1.8 years. There was no significant difference between the knowledge of the consequences of missing teeth and sex or on level of education (p(·) 0.05). Dentists constituted the largest source of information to these patients (25.6%) while the media constituted the least (0.5%). The result of this study showed poor knowledge of the consequences of missing teeth among partially edentulous patients and the media that should be of assistance were equally unaware, signifying urgent need for public awareness on this subject.

  19. "Early baby teeth": Folklore and facts.

    PubMed

    Maheswari, N Uma; Kumar, B P; Karunakaran; Kumaran, S Thanga

    2012-08-01

    Variations in the newborns' oral cavity have been an enduring interest to the pediatric dentist. The occurrence of natal and neonatal teeth is a rare anomaly, which for centuries has been associated with diverse superstitions among many different ethnic groups. Natal teeth are more frequent than neonatal teeth, the ratio being approximately 3:1. The purpose of this case report is to review the literature related to the natal teeth folklore and misconceptions and discuss their possible etiology and treatment.

  20. SOLAR ERUPTION AND LOCAL MAGNETIC PARAMETERS

    SciTech Connect

    Lee, Jeongwoo; Chae, Jongchul; Liu, Chang

    2016-11-10

    It is now a common practice to use local magnetic parameters such as magnetic decay index for explaining solar eruptions from active regions, but there can be an alternative view that the global properties of the source region should be counted as a more important factor. We discuss this issue based on Solar Dynamics Observatory observations of the three successive eruptions within 1.5 hr from the NOAA active region 11444 and the magnetic parameters calculated using the nonlinear force-free field model. Two violent eruptions occurred in the regions with relatively high magnetic twist number (0.5–1.5) and high decay index (0.9–1.1)more » at the nominal height of the filament (12″) and otherwise a mild eruption occurred, which supports the local-parameter paradigm. Our main point is that the time sequence of the eruptions did not go with these parameters. It is argued that an additional factor, in the form of stabilizing force, should operate to determine the onset of the first eruption and temporal behaviors of subsequent eruptions. As supporting evidence, we report that the heating and fast plasma flow continuing for a timescale of an hour was the direct cause for the first eruption and that the unidirectional propagation of the disturbance determined the timing of subsequent eruptions. Both of these factors are associated with the overall magnetic structure rather than local magnetic properties of the active region.« less

  1. Large Prominence Eruption (October 3, 2014)

    NASA Image and Video Library

    2017-12-08

    The STEREO (Behind) spacecraft captured this large prominence and corona mass ejection as they erupted into space (Sept. 26, 2014). By combining images from three instruments, scientists can see the eruption itself (in extreme UV light) as well as follow its progression over the period of about 13 hours with its two coronagraphs. Credit: NASA/Goddard/STEREO The STEREO (Behind) spacecraft captured this large prominence and corona mass ejection as they erupted into space (Sept. 26, 2014). By combining images from three instruments, scientists can see the eruption itself (in extreme UV light) as well as follow its progression over the period of about 13 hours with its two coronagraphs.

  2. Winter warming from large volcanic eruptions

    NASA Technical Reports Server (NTRS)

    Robock, Alan; Mao, Jianping

    1992-01-01

    An examination of the Northern Hemisphere winter surface temperature patterns after the 12 largest volcanic eruptions from 1883-1992 shows warming over Eurasia and North America and cooling over the Middle East which are significant at the 95-percent level. This pattern is found in the first winter after tropical eruptions, in the first or second winter after midlatitude eruptions, and in the second winter after high latitude eruptions. The effects are independent of the hemisphere of the volcanoes. An enhanced zonal wind driven by heating of the tropical stratosphere by the volcanic aerosols is responsible for the regions of warming, while the cooling is caused by blocking of incoming sunlight.

  3. Winter warming from large volcanic eruptions

    NASA Technical Reports Server (NTRS)

    Robock, Alan; Mao, Jianping

    1992-01-01

    An examination of the Northern Hemisphere winter surface temperature patterns after the 12 largest volcanic eruptions from 1883-1992 shows warming over Eurasia and North America and cooling over the Middle East which are significant at the 95 percent level. This pattern is found in the first winter after tropical eruptions, in the first or second winter after midlatitude eruptions, and in the second winter after high latitude eruptions. The effects are independent of the hemisphere of the volcanoes. An enhanced zonal wind driven by heating of the tropical stratosphere by the volcanic aerosols is responsible for the regions of warming, while the cooling is caused by blocking of incoming sunlight.

  4. Cleidocranial dysplasia presenting with retained deciduous teeth in a 15-year-old girl: a case report

    PubMed Central

    2012-01-01

    Introduction Cleidocranial dysplasia is a rare congenital defect of autosomal dominant inheritance caused by mutations in the Cbfa1 gene, also called Runx2, located on the short arm of chromosome 6. It primarily affects bones which undergo intramembranous ossification. This condition is of clinical significance to dentistry due to the involvement of the facial bones, altered eruption patterns and multiple supernumerary teeth. Case presentation Our patient, a 15-year-old Indian girl, presented with the typical features of prolonged retention of deciduous dentition and delayed eruption of permanent teeth, that is, mandibular prognathism along with other skeletal abnormalities like shrugged shoulder and the absence of clavicles. A multidisciplinary approach was followed, comprising orthodontic, surgical and pedodontic teams for management. Conclusion Successful treatment of such a case lies in a holistic approach that takes care of all aspects, including the primary pathology, the deformity itself and even the psychological angle. PMID:22260259

  5. Splinting of traumatized teeth in children.

    PubMed

    Brown, Charlotte L; Mackie, Iain C

    2003-03-01

    Different types of splints have been used to stabilize traumatized teeth in children. Some of these splints have compromised healing of the teeth and associated dental tissues. This article considers the ideal properties for a splint and describes a method of splinting traumatized teeth in children that meets most of the requirements of an ideal splint.

  6. Cracked Teeth: A Review of the Literature

    PubMed Central

    Lubisich, Erinne B.; Hilton, Thomas J.; FERRACANE, JACK

    2013-01-01

    Although cracked teeth are a common problem for patients and dentists, there is a dearth of evidence-based guidelines on how to prevent, diagnose, and treat cracks in teeth. The purpose of this article is to review the literature to establish what evidence exists regarding the risk factors for cracked teeth and their prevention, diagnosis, and treatment. PMID:20590967

  7. CRITICAL ANALYSIS OF ARTIFICIAL TEETH FOR ENDODONTIC TEACHING

    PubMed Central

    Nassri, Maria Renata Giazzi; Carlik, Jaime; da Silva, Camila Roberta Nepomuceno; Okagawa, Renata Elisa; Lin, Suzy

    2008-01-01

    The purpose of this study was to evaluate the use of artificial teeth for endodontic teaching. A questionnaire was prepared and submitted to 18 professors of Endodontics from different Brazilian universities to evaluate the following features of five cloudy resin artificial teeth: internal and external anatomy; coronal chambers regarding their size, shape and canal path; root canal regarding their size, shape and position; fulfillment of the pulp chamber and root canals by considering the texture, quantity, color, and ease of handling; resin hardness and visualization of the radiographic image. The results presented favorable opinions, in terms of internal and external anatomy, coronal pulp chambers and root canal and handling and radiographic imaging. The contents of the pulp space and hardness of the teeth were considered satisfactory. The average grade assigned to the artificial tooth quality was 8.4, in a 0-10 scale. In conclusion, the artificial teeth have potential to replace the natural teeth in endodontic teaching; however, improvements are still necessary to reach a better quality model. PMID:19089288

  8. Pattern of transmission of laser light through carious molar teeth.

    PubMed

    Chandler, N P; Pitt Ford, T R; Watson, T F

    2001-10-01

    The aims of this study were to investigate the pattern of transmission of laser light through carious human molar teeth, and to examine the effect on light transmission of reactions to caries in the dentine. Sectioned carious human molars were examined whilst illuminated from their external surfaces by a helium-neon laser probe of 0.5 mm diameter. The pattern of light transmission was observed and selected specimens were photographed. The passage of light through the surrounding dentine toward the pulp space was investigated by confocal microscopy. Further carious and restored teeth were illuminated from three buccal and three lingual sites to establish the probability of light being able to reach the coronal pulp space. For all 31 teeth examined, it was possible to illuminate the pulp space from a position on the buccal side. The presence of intracoronal restorations did not necessarily prevent light transmission to the pulp. Confocal microscopy demonstrated conduction of light within dystrophic deposits of irregular secondary dentine. The presence of carious lesions or restorations in molar teeth does not necessarily interfere with transmission of laser light to the pulp space. Light is conducted within irregular secondary dentine. With appropriate probe placement, assessments of pulp health in diseased posterior teeth may be possible using laser Doppler flowmetry.

  9. Forensic DNA typing from teeth using demineralized root tips.

    PubMed

    Corrêa, Heitor Simões Dutra; Pedro, Fabio Luis Miranda; Volpato, Luiz Evaristo Ricci; Pereira, Thiago Machado; Siebert Filho, Gilberto; Borges, Álvaro Henrique

    2017-11-01

    Teeth are widely used samples in forensic human genetic identification due to their persistence and practical sampling and processing. Their processing, however, has changed very little in the last 20 years, usually including powdering or pulverization of the tooth. The objective of this study was to present demineralized root tips as DNA sources while, at the same time, not involving powdering the samples or expensive equipment for teeth processing. One to five teeth from each of 20 unidentified human bodies recovered from midwest Brazil were analyzed. Whole teeth were demineralized in EDTA solution with daily solution change. After a maximum of approximately seven days, the final millimeters of the root tip was excised. This portion of the sample was used for DNA extraction through a conventional organic protocol. DNA quantification and STR amplification were performed using commercial kits followed by capillary electrophoresis on 3130 or 3500 genetic analyzers. For 60% of the unidentified bodies (12 of 20), a full genetic profile was obtained from the extraction of the first root tip. By the end of the analyses, full genetic profiles were obtained for 85% of the individuals studied, of which 80% were positively identified. This alternative low-tech approach for postmortem teeth processing is capable of extracting DNA in sufficient quantity and quality for forensic casework, showing that root tips are viable nuclear DNA sources even after demineralization. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Eruption pattern of permanent molars: implications for school-based dental sealant programs.

    PubMed

    Kuthy, R A; Ashton, J J

    1989-01-01

    Dental caries remains a prevalent, chronic disease of childhood. The preponderance of dental caries is located on the pit and fissure surfaces of teeth, an area where dental sealants are most effective in preventing this malady. In the school year 1987-88, 4,879 Ohio schoolchildren participated in an assessment of dental health. Grades chosen for this assessment included 1, 2, 3, 6, 7, 8, and 11. This study focuses on eruption of first and second permanent molars in development of a timing strategy for placement of occlusal sealants in a school-based program. An eruption score was developed for the determination of the first or second molar eruption status for each child. The data were analyzed for grade, sex, race, locale, fluoridation status, and percent of children on free or reduced-cost lunch programs. Analyses were performed on 2,215 children in grades 1-3 and 1,840 children in grades 6-8. Fifty-seven percent of first graders had all first permanent molars sufficiently erupted for sealant placement on the occlusal surface. Likewise, 23.6 percent of sixth graders had sufficient occlusal exposure on the second molar. Females showed an earlier eruption pattern than males for both first (P less than .05) and second (P less than .001) molars. Black children preceded white children only in the eruption of the second molar (P less than .001). This study provides dental public health decision makers with state-specific information on the earliest time to initiate a school-based occlusal sealant program.(ABSTRACT TRUNCATED AT 250 WORDS)

  11. Fracture modes in human teeth.

    PubMed

    Lee, J J-W; Kwon, J-Y; Chai, H; Lucas, P W; Thompson, V P; Lawn, B R

    2009-03-01

    The structural integrity of teeth under stress is vital to functional longevity. We tested the hypothesis that this integrity is limited by fracture of the enamel. Experiments were conducted on molar teeth, with a metal rod loaded onto individual cusps. Fracture during testing was tracked with a video camera. Two longitudinal modes of cracking were observed: median cracking from the contact zone, and margin cracking along side walls. Median cracks initiated from plastic damage at the contact site, at first growing slowly and then accelerating to the tooth margin. Margin cracks appeared to originate from the cemento-enamel junction, and traversed the tooth wall adjacent to the loaded cusp from the gingival to the occlusal surface. All cracks remained confined within the enamel shell up to about 550 N. At higher loads, additional crack modes--such as enamel chipping and delamination--began to manifest themselves, leading to more comprehensive failure of the tooth structure.

  12. Microfilament-Eruption Mechanism for Solar Spicules

    NASA Technical Reports Server (NTRS)

    Sterling, Alphonse C.; Moore, Ronald L.

    2017-01-01

    Recent studies indicate that solar coronal jets result from eruption of small-scale filaments, or "minifilaments" (Sterling et al. 2015, Nature, 523, 437; Panesar et al. ApJL, 832L, 7). In many aspects, these coronal jets appear to be small-scale versions of long-recognized large-scale solar eruptions that are often accompanied by eruption of a large-scale filament and that produce solar flares and coronal mass ejections (CMEs). In coronal jets, a jet-base bright point (JBP) that is often observed to accompany the jet and that sits on the magnetic neutral line from which the minifilament erupts, corresponds to the solar flare of larger-scale eruptions that occurs at the neutral line from which the large-scale filament erupts. Large-scale eruptions are relatively uncommon (approximately 1 per day) and occur with relatively large-scale erupting filaments (approximately 10 (sup 5) kilometers long). Coronal jets are more common (approximately 100s per day), but occur from erupting minifilaments of smaller size (approximately 10 (sup 4) kilometers long). It is known that solar spicules are much more frequent (many millions per day) than coronal jets. Just as coronal jets are small-scale versions of large-scale eruptions, here we suggest that solar spicules might in turn be small-scale versions of coronal jets; we postulate that the spicules are produced by eruptions of "microfilaments" of length comparable to the width of observed spicules (approximately 300 kilometers). A plot of the estimated number of the three respective phenomena (flares/CMEs, coronal jets, and spicules) occurring on the Sun at a given time, against the average sizes of erupting filaments, minifilaments, and the putative microfilaments, results in a size distribution that can be fitted with a power-law within the estimated uncertainties. The counterparts of the flares of large-scale eruptions and the JBPs of jets might be weak, pervasive, transient brightenings observed in Hinode/CaII images, and

  13. The 2014 eruptions of Pavlof Volcano, Alaska

    USGS Publications Warehouse

    Waythomas, Christopher F.; Haney, Matthew M.; Wallace, Kristi; Cameron, Cheryl E.; Schneider, David J.

    2017-12-22

    Pavlof Volcano is one of the most frequently active volcanoes in the Aleutian Island arc, having erupted more than 40 times since observations were first recorded in the early 1800s . The volcano is located on the Alaska Peninsula (lat 55.4173° N, long 161.8937° W), near Izembek National Wildlife Refuge. The towns and villages closest to the volcano are Cold Bay, Nelson Lagoon, Sand Point, and King Cove, which are all within 90 kilometers (km) of the volcano (fig. 1). Pavlof is a symmetrically shaped stratocone that is 2,518 meters (m) high, and has about 2,300 m of relief. The volcano supports a cover of glacial ice and perennial snow roughly 2 to 4 cubic kilometers (km3) in volume, which is mantled by variable amounts of tephra fall, rockfall debris, and pyroclastic-flow deposits produced during historical eruptions. Typical Pavlof eruptions are characterized by moderate amounts of ash emission, lava fountaining, spatter-fed lava flows, explosions, and the accumulation of unstable mounds of spatter on the upper flanks of the volcano. The accumulation and subsequent collapse of spatter piles on the upper flanks of the volcano creates hot granular avalanches, which erode and melt snow and ice, and thereby generate watery debris-flow and hyperconcentrated-flow lahars. Seismic instruments were first installed on Pavlof Volcano in the early 1970s, and since then eruptive episodes have been better characterized and specific processes have been documented with greater certainty. The application of remote sensing techniques, including the use of infrasound data, has also aided the study of more recent eruptions. Although Pavlof Volcano is located in a remote part of Alaska, it is visible from Cold Bay, Sand Point, and Nelson Lagoon, making distal observations of eruptive activity possible, weather permitting. A busy air-travel corridor that is utilized by a numerous transcontinental and regional air carriers passes near Pavlof Volcano. The frequency of air travel

  14. Flux Cancellation Leading to Solar Filament Eruptions

    NASA Astrophysics Data System (ADS)

    Popescu, R. M.; Panesar, N. K.; Sterling, A. C.; Moore, R. L.

    2016-12-01

    Solar filaments are strands of relatively cool, dense plasma magnetically suspended in the lower density hotter solar corona. They trace magnetic polarity inversion lines (PILs) in the photosphere below, and are supported against gravity at heights of up to 100 Mm above the chromosphere by the magnetic field in and around them. This field erupts when it is rendered unstable by either magnetic flux cancellation or emergence at or near the PIL. We have studied the evolution of photospheric magnetic flux leading to ten observed filament eruptions. Specifically, we look for gradual magnetic changes in the neighborhood of the PIL prior to and during eruption. We use Extreme Ultraviolet (EUV) images from the Atmospheric Imaging Assembly (AIA), and magnetograms from the Helioseismic and Magnetic Imager (HMI), both onboard the Solar Dynamics Observatory (SDO), to study filament eruptions and their photospheric magnetic fields. We examine whether flux cancellation or/and emergence leads to filament eruptions and find that continuous flux cancellation was present at the PIL for many hours prior to each eruption. We present two events in detail and find the following: (a) the pre-eruption filament-holding core field is highly sheared and appears in the shape of a sigmoid above the PIL; (b) at the start of the eruption the opposite arms of the sigmoid reconnect in the middle above the site of (tether-cutting) flux cancellation at the PIL; (c) the filaments first show a slow-rise, followed by a fast-rise as they erupt. We conclude that these two filament eruptions result from flux cancellation in the middle of the sheared field and are in agreement with the standard model for a CME/flare filament eruption from a closed bipolar magnetic field [flux cancellation (van Ballegooijen and Martens 1989 and Moore and Roumelrotis 1992) and runaway tether-cutting (Moore et. al 2001)].

  15. Variations in eruption style during the 1931 A.D. eruption of Aniakchak volcano, Alaska

    USGS Publications Warehouse

    Nicholson, Robert S.; Gardner, James E.; Neal, Christina A.

    2011-01-01

    The 1931 A.D. eruption of Aniakchak volcano, Alaska, progressed from subplinian to effusive eruptive style and from trachydacite to basaltic andesite composition from multiple vent locations. Eyewitness accounts and new studies of deposit stratigraphy provide a combined narrative of eruptive events. Additional field, compositional, grain size, componentry, density, and grain morphology data document the influences on changing eruptive style as the eruption progressed. The eruption began on 1 May 1931 A.D. when a large subplinian eruption column produced vesicular juvenile-rich tephra. Subsequent activity was more intermittent, as magma interacted with groundwater and phreatomagmatic ash and lithic-rich tephra was dispersed up to 600 km downwind. Final erupted products were more mafic in composition and the eruption became more strombolian in style. Stratigraphic evidence suggests that two trachydacitic lava flows were erupted from separate but adjacent vents before the phreatomagmatic phase concluded and that basaltic andesite lava from a third vent began to effuse near the end of explosive activity. The estimated total bulk volume of the eruption is 0.9 km3, which corresponds to approximately 0.3 km3 of magma. Eruption style changes are interpreted as follows: (1) a decrease in magma supply rate caused the change from subplinian to phreatomagmatic eruption; (2) a subsequent change in magma composition caused the transition from phreatomagmatic to strombolian eruption style. Additionally, the explosion and effusion of a similar magma composition from three separate vents indicates how the pre-existing caldera structure controlled the pathway of shallow magma ascent, thus influencing eruption style.

  16. Variations in eruption style during the 1931A.D. eruption of Aniakchak volcano, Alaska

    USGS Publications Warehouse

    Nicholson, R.S.; Gardner, J.E.; Neal, C.A.

    2011-01-01

    The 1931A.D. eruption of Aniakchak volcano, Alaska, progressed from subplinian to effusive eruptive style and from trachydacite to basaltic andesite composition from multiple vent locations. Eyewitness accounts and new studies of deposit stratigraphy provide a combined narrative of eruptive events. Additional field, compositional, grain size, componentry, density, and grain morphology data document the influences on changing eruptive style as the eruption progressed. The eruption began on 1 May 1931A.D. when a large subplinian eruption column produced vesicular juvenile-rich tephra. Subsequent activity was more intermittent, as magma interacted with groundwater and phreatomagmatic ash and lithic-rich tephra was dispersed up to 600km downwind. Final erupted products were more mafic in composition and the eruption became more strombolian in style. Stratigraphic evidence suggests that two trachydacitic lava flows were erupted from separate but adjacent vents before the phreatomagmatic phase concluded and that basaltic andesite lava from a third vent began to effuse near the end of explosive activity. The estimated total bulk volume of the eruption is 0.9km3, which corresponds to approximately 0.3km3 of magma. Eruption style changes are interpreted as follows: (1) a decrease in magma supply rate caused the change from subplinian to phreatomagmatic eruption; (2) a subsequent change in magma composition caused the transition from phreatomagmatic to strombolian eruption style. Additionally, the explosion and effusion of a similar magma composition from three separate vents indicates how the pre-existing caldera structure controlled the pathway of shallow magma ascent, thus influencing eruption style. ?? 2011 Elsevier B.V..

  17. Natal Teeth: A Case Report and Reappraisal

    PubMed Central

    Malki, Ghadah A.; Al-Badawi, Emad A.; Dahlan, Mohammad A.

    2015-01-01

    The presence of teeth at birth (natal teeth) or within a month after delivery (neonatal teeth) is a rare condition. Natal and neonatal teeth are conditions of significant importance to pediatric dentists and pediatricians. This report discusses a case in which a five-day-old infant required extraction of a mobile mandibular natal tooth to avoid the risk of aspiration and interference with feeding. Also, a review of the literature was conducted to discuss the etiology, clinical features, complications, and management of natal and neonatal teeth. PMID:25722895

  18. Jupiter Eruptions Captured in Infrared

    NASA Technical Reports Server (NTRS)

    2008-01-01

    [figure removed for brevity, see original site] Click on the image for high resolution image of Nature Cover

    Detailed analysis of two continent-sized storms that erupted in Jupiter's atmosphere in March 2007 shows that Jupiter's internal heat plays a significant role in generating atmospheric disturbances. Understanding these outbreaks could be the key to unlock the mysteries buried in the deep Jovian atmosphere, say astronomers.

    This infrared image shows two bright plume eruptions obtained by the NASA Infrared Telescope Facility on April 5, 2007.

    Understanding these phenomena is important for Earth's meteorology where storms are present everywhere and jet streams dominate the atmospheric circulation. Jupiter is a natural laboratory where atmospheric scientists study the nature and interplay of the intense jets and severe atmospheric phenomena.

    According to the analysis, the bright plumes were storm systems triggered in Jupiter's deep water clouds that moved upward in the atmosphere vigorously and injected a fresh mixture of ammonia ice and water about 20 miles (30 kilometers) above the visible clouds. The storms moved in the peak of a jet stream in Jupiter's atmosphere at 375 miles per hour (600 kilometers per hour). Models of the disturbance indicate that the jet stream extends deep in the buried atmosphere of Jupiter, more than 60 miles (approximately100 kilometers) below the cloud tops where most sunlight is absorbed.

  19. Influence of metabolic-linked early life factors on the eruption timing of the first primary tooth.

    PubMed

    Un Lam, Carolina; Hsu, Chin-Ying Stephen; Yee, Robert; Koh, David; Lee, Yung Seng; Chong, Mary Foong-Fong; Cai, Meijin; Kwek, Kenneth; Saw, Seang Mei; Godfrey, Keith; Gluckman, Peter; Chong, Yap Seng

    2016-11-01

    Early eruption of permanent teeth has been associated with childhood obesity and diabetes mellitus, suggesting links between tooth eruption and metabolic conditions. This longitudinal study aimed to identify pre-, peri- and postnatal factors with metabolic consequences during infancy that may affect the eruption timing of the first primary tooth (ETFT) in children from an ethnically heterogeneous population residing within the same community. Participants were recruited (n = 1033) through the GUSTO (Growing Up in Singapore Towards healthy Outcomes) birth cohort (n = 1237). Oral examinations were performed at 3-month intervals from 6 to 18 months of age. Crude and adjusted analyses, with generalized linear modelling, were conducted to link ETFT to potential determinants occurring during pregnancy, delivery/birth and early infancy. Overall mean eruption age of the first primary tooth was 8.5 (SD 2.6) months. Earlier tooth eruption was significantly associated with infant's rate of weight gain during the first 3 months of life and increased maternal childbearing age. Compared to their Chinese counterparts, Malay and Indian children experienced significantly delayed tooth eruption by 1.2 and 1.7 months, respectively. Infant weight gain from birth to 3 months, ethnicity and maternal childbearing age were significant determinants of first tooth eruption timing. Early life influences can affect primary tooth development, possibly via metabolic pathways. Timing of tooth eruption is linked to general growth and metabolic function. Therefore, it has potential in forecasting oral and systemic conditions such as caries and obesity.

  20. Calbuco Volcano Erupts in Southern Chile

    NASA Image and Video Library

    2015-04-24

    Calbuco Volcano in southern Chile has erupted for the first time since 1972, with the last major eruption occurring in 1961 that sent ash columns 12-15 kilometers high. This image was taken by the Suomi NPP satellite's VIIRS instrument in a high resolution infrared channel around 0515Z on April 23, 2015. Credit: NOAA/NASA/NPP/VIIRS

  1. Brief communication: The London atlas of human tooth development and eruption.

    PubMed

    AlQahtani, S J; Hector, M P; Liversidge, H M

    2010-07-01

    The aim of this study was to develop a comprehensive evidence-based atlas to estimate age using both tooth development and alveolar eruption for human individuals between 28 weeks in utero and 23 years. This was a cross-sectional, retrospective study of archived material with the sample aged 2 years and older having a uniform age and sex distribution. Developing teeth from 72 prenatal and 104 postnatal skeletal remains of known age-at-death were examined from collections held at the Royal College of Surgeons of England and the Natural History Museum, London, UK (M 91, F 72, unknown sex 13). Data were also collected from dental radiographs of living individuals (M 264, F 264). Median stage for tooth development and eruption for all age categories was used to construct the atlas. Tooth development was determined according to Moorrees et al. (J Dent Res 42 (1963a) 490-502; Am J Phys Anthropol 21 (1963b) 205-213) and eruption was assessed relative to the alveolar bone level. Intraexaminer reproducibility calculated using Kappa on 150 teeth was 0.90 for 15 skeletal remains of age <2 years, and 0.81 from 605 teeth (50 radiographs). Age categories were monthly in the last trimester, 2 weeks perinatally, 3-month intervals during the first year, and at every year thereafter. Results show that tooth formation is least variable in infancy and most variable after the age of 16 years for the development of the third molar. (c) 2010 Wiley-Liss, Inc.

  2. Mechanism of Human Tooth Eruption: Review Article Including a New Theory for Future Studies on the Eruption Process

    PubMed Central

    Kjær, Inger

    2014-01-01

    Human eruption is a unique developmental process in the organism. The aetiology or the mechanism behind eruption has never been fully understood and the scientific literature in the field is extremely sparse. Human and animal tissues provide different possibilities for eruption analyses, briefly discussed in the introduction. Human studies, mainly clinical and radiological, have focused on normal eruption and gender differences. Why a tooth begins eruption and what enables it to move eruptively and later to end these eruptive movements is not known. Pathological eruption courses contribute to insight into the aetiology behind eruption. A new theory on the eruption mechanism is presented. Accordingly, the mechanism of eruption depends on the correlation between space in the eruption course, created by the crown follicle, eruption pressure triggered by innervation in the apical root membrane, and the ability of the periodontal ligament to adapt to eruptive movements. Animal studies and studies on normal and pathological eruption in humans can support and explain different aspects in the new theory. The eruption mechanism still needs elucidation and the paper recommends that future research on eruption keeps this new theory in mind. Understanding the aetiology of the eruption process is necessary for treating deviant eruption courses. PMID:24688798

  3. Chronology of Postglacial Eruptive Activity and Calculation of Eruption Probabilities for Medicine Lake Volcano, Northern California

    USGS Publications Warehouse

    Nathenson, Manuel; Donnelly-Nolan, Julie M.; Champion, Duane E.; Lowenstern, Jacob B.

    2007-01-01

    Medicine Lake volcano has had 4 eruptive episodes in its postglacial history (since 13,000 years ago) comprising 16 eruptions. Time intervals between events within the episodes are relatively short, whereas time intervals between the episodes are much longer. An updated radiocarbon chronology for these eruptions is presented that uses paleomagnetic data to constrain the choice of calibrated ages. This chronology is used with exponential, Weibull, and mixed-exponential probability distributions to model the data for time intervals between eruptions. The mixed exponential distribution is the best match to the data and provides estimates for the conditional probability of a future eruption given the time since the last eruption. The probability of an eruption at Medicine Lake volcano in the next year from today is 0.00028.

  4. An integrated model for underground eruption dynamics

    NASA Astrophysics Data System (ADS)

    Colucci, Simone; Papale, Paolo

    2017-04-01

    Ubiquitous analyses of the products of volcanic eruptions reveal discharge of magmas initially stored at multiple levels inside the crust, giving rise to complex patterns of mixing and overall evolution of composition. The resulting eruption dynamics and eruption duration depend on the interplay between such different magmas and the evolution of the conditions in the different domains from their provenance to the surface. We have developed a simple dynamic model that allows to investigate the evolution of an eruption, in terms of space distribution of flow quantities from depth to surface, mass flow rate, and overall duration, in a composite system including vertically distributed dykes, conduits and chambers interacting with each other. A sensitivity analysis allows to identify the parameters (e.g., magma composition(s), volatile contents, size of the different domains, depth of the plumbing system, etc.) that have more relevant roles in determining the evolution and magnitude of the resulting eruption.

  5. Observation of interactions between two erupting filaments

    NASA Astrophysics Data System (ADS)

    Liu, Yu; Su, Jiangtao; Shen, Yuandeng; Yang, Liheng

    2010-02-01

    Following the first observational study of the interaction between two distinct filaments (Su et al. 2007; hereafter, event 1), we present another interesting case observed by SMART telescope on 2005 June 25 with higher spatial resolution (hereafter, event 2). The two events are compared with each other. In event 1 the two filaments erupted subsequently and obvious mass flow was observed to be transferred from one erupting filament to one stable filament which triggered its eruption. On the contrary, in event 2, the two filaments erupted simultaneously and there was no transfer of material noticed between them during the initial stage. The two filaments merged together along the ejection path, indicating the bodily coalesce between the two interacting flux ropes. Moreover, event 1 was associated with a coronal mass ejection (CME), while event 2 was a failed filament eruption, thus without CME association.

  6. Molar distalization with pendulum appliances in the mixed dentition: effects on the position of unerupted canines and premolars.

    PubMed

    Kinzinger, Gero S M; Wehrbein, Heinrich; Gross, Ulrich; Diedrich, Peter R

    2006-03-01

    The pendulum appliance allows for rapid molar distalization without the need for patient compliance. Its efficiency has been confirmed in a number of clinical studies. However, the potential interactions and positional changes between the deciduous molars used for dental anchorage and the erupted and unerupted permanent teeth have yet to be clarified when this appliance is used for molar distalization in the mixed dentition. Twenty-nine patients in the mixed dentition each received a modified pendulum appliance with a distal screw and a preactivated pendulum spring for bilateral distalization of the maxillary molars. The patients were divided into 4 groups based on dentition stages: patient group 1 (PG 1, n = 10) was in the early mixed dentition; patients had resorption of the distal root areas of the deciduous molars being used for dental anchorage, and the unerupted premolars were located at the distal margin of the deciduous molar root region. Based on radiographs taken before placement of the pendulum appliance, patient group 2 (PG 2, n = 10) was diagnosed as having a central location of the unerupted premolars. In the third group (PG 3, n = 4), the first premolars were already erupted and could be integrated into the dental anchorage, but the canines were not yet erupted. In the fourth group (PG 4, n = 5), the first premolars and both canines were fully erupted. Statistical analysis of the measured results showed significant differences in the side effects between PG 1 and PG 2. In patients being treated with pendulum appliances, the anchorage quality of the deciduous molars that were already partially resorbed in the distal root area was comparatively reduced. Consequently, the mesial drift of the deciduous molars and incisors was increased, without impairing the extent and quality of the molar distalization. Anchorage loss in the supporting area had no direct impact on the sagittal position of the unerupted premolars in the early mixed dentition. If

  7. Stratigraphy and eruption history of pre-Green Tuff peralkaline welded ignimbrites, Pantelleria, Italy

    NASA Astrophysics Data System (ADS)

    Jordan, Nina; Branney, Mike, ,, Dr; Williams, Rebecca, ,, Dr; Norry, Mike, ,, Dr

    2013-04-01

    A revised volcanic stratigraphy is presented for the ignimbrites of Pantelleria, a peralkaline caldera volcano situated in the submerged continental rift between Africa and Sicily. The volcano has been active for ×325 ka (Mahood & Hildreth, 1986), producing eight major ignimbrites from large central eruptions, which appear to have alternated with numerous minor pumice falls and lavas from scattered local centres. The main ignimbrites can be traced along superb coastal exposures and have been logged in detail. Eruption-units have been defined by the position of palaeosols and a type section designated. Lithic breccias and pumice fall deposits associated with these major ignimbrites are interpreted as part of the same eruption overcoming correlation problems encountered by previous workers (cf Mahood & Hildreth, 1986). The ignimbrites are 2 to >20 m thick, welded to rheomorphic and cover most of the island, recording devastating, radial, high-temperature density currents. Five of the eight major ignimbrites contain lithic breccias, which have commonly been interpreted as recording caldera collapse events, but the details of individual calderas are not clear. The ignimbrites were erupted between 181 and 50 ka suggesting that the early history of the island (325 to 181 ka) differs from later stages in that only local pumice and lava-producing eruptions have occurred. This means that the amount of erupted magma increased in the later stage as the ignimbrites represent eruptions of many times the volume of the local centres. Distal peralkaline tephras have been found around the Mediterranean as far away as ~1200 km. With only this volcano erupting peralkaline compositions, it suggests that eruptions from Pantelleria have had a substantial impact on their environment. We infer that there were few Plinian events on the island, and that the distal tephras may be co-ignimbrite ashfall deposits. REFERENCES: Mahood, G.A., Hildreth, W., (1986) Bulletin of Volcanology 48, 143-172.

  8. A Labially Positioned Mesiodens and Its Repositioning as a Missing Central Incisor

    PubMed Central

    Ephraim, Rena; Dilna, N C; Sreedevi, S; Shubha, M

    2014-01-01

    Hyperdontia is an increased number of teeth within the dental arches. This is of particular interest to pediatric dentists who commonly make the initial diagnosis. Most often a large portion of these teeth is completely embedded or impacted within the jaws and can be viewed only radiographically. Hyperdontia can occur on virtually every tooth-bearing surface. However, the most frequent is the mesiodens, in the anterior maxillary region. Anterior maxillary teeth are one of the most important features contributing to aesthetics of an individual. Missing anterior teeth can cause undue psychological stress in children, during their growing years. Most of the literature available show that the mesiodens are situated on the palatal aspect of the permanent incisors. Their treatment frequently involves an early recognition, extraction through a traditional palatal technique and guiding the associated permanent tooth to its original position. The purpose of this article is to enlighten the clinician of the need of deviating from the traditional approach of early extraction in particular situations and to conserve the mesiodens if favorable as an alternative treatment to a malformed permanent tooth, which may fail to erupt. This report describes a successful multidisciplinary approach to treatment of a unerrupted, labially placed mesiodens in conjunction with a dilacerated and impacted permanent tooth, in a child with a missing left central incisor. Treatment consisted of localizing and confirming the placement of the mesiodens to be labial, surgically exposing the crown of the mesiodens through a labial surgical approach, orthodontically guiding it to the position of the missing central incisor, extracting the malformed permanent incisor, and restoring the mesiodens to the required anatomy with composites, to establish aesthetics and function of the affected region. PMID:25395807

  9. A labially positioned mesiodens and its repositioning as a missing central incisor.

    PubMed

    Ephraim, Rena; Dilna, N C; Sreedevi, S; Shubha, M

    2014-09-01

    Hyperdontia is an increased number of teeth within the dental arches. This is of particular interest to pediatric dentists who commonly make the initial diagnosis. Most often a large portion of these teeth is completely embedded or impacted within the jaws and can be viewed only radiographically. Hyperdontia can occur on virtually every tooth-bearing surface. However, the most frequent is the mesiodens, in the anterior maxillary region. Anterior maxillary teeth are one of the most important features contributing to aesthetics of an individual. Missing anterior teeth can cause undue psychological stress in children, during their growing years. Most of the literature available show that the mesiodens are situated on the palatal aspect of the permanent incisors. Their treatment frequently involves an early recognition, extraction through a traditional palatal technique and guiding the associated permanent tooth to its original position. The purpose of this article is to enlighten the clinician of the need of deviating from the traditional approach of early extraction in particular situations and to conserve the mesiodens if favorable as an alternative treatment to a malformed permanent tooth, which may fail to erupt. This report describes a successful multidisciplinary approach to treatment of a unerrupted, labially placed mesiodens in conjunction with a dilacerated and impacted permanent tooth, in a child with a missing left central incisor. Treatment consisted of localizing and confirming the placement of the mesiodens to be labial, surgically exposing the crown of the mesiodens through a labial surgical approach, orthodontically guiding it to the position of the missing central incisor, extracting the malformed permanent incisor, and restoring the mesiodens to the required anatomy with composites, to establish aesthetics and function of the affected region.

  10. Forecasting eruptions using pre-eruptive seismic patterns at Sinabung Volcano, Indonesia

    NASA Astrophysics Data System (ADS)

    McCausland, W. A.; White, R. A.; Hendrasto, M.; Gunawan, H.; Indrastuti, N.; Triastuti, H.; Suparman, Y.; Putra, A.

    2015-12-01

    Forecasting the size, timing and style of volcanic eruptions is of primary interest to observatories and civil authorities world-wide, yet most observatories only have access to long-term data at a very limited number of volcanoes under their jurisdiction. When extensive long-term data sets are available to responsible agencies, volcanic eruptive size, timing and style can usually be successfully forecast using current monitoring data and knowledge of precursory eruptive patterns, enabling the communication of timely forecasts to civil authorities. Experienced agencies, such as Indonesia's Center for Volcanology and Geologic Hazards Mitigation and the USAID-USGS Volcano Disaster Assistance Program, utilize extensive collective experiences with multiple monitoring streams over multiple eruption cycles and across volcano types to successfully forecast eruption size, style and onset, as well as changes in eruptive style and size within ongoing eruptions. The longest-term real-time monitoring parameter commonly available at volcanoes worldwide is seismic data. Seismic data is a direct measure of rate-dependent strain changes in the magmatic system from the deep magmatic input to shallow eruptive processes. Patterns of pre-eruptive earthquakes coupled with other available monitoring data and conceptual models of magma ascent enable short-term forecasting of eruption size, style, and onset. First order event locations, characterization of background seismicity, and changes in earthquake types and energy release are most important to successful eruption forecasting. This study demonstrates how this approach has been used to successfully forecast eruption onsets, changes in eruptive style, and to change alert levels and extend or contract evacuation zones during the ongoing eruption of Sinabung Volcano, Indonesia.

  11. Large, Moderate or Small? The Challenge of Measuring Mass Eruption Rates in Volcanic Eruptions

    NASA Astrophysics Data System (ADS)

    Gudmundsson, M. T.; Dürig, T.; Hognadottir, T.; Hoskuldsson, A.; Bjornsson, H.; Barsotti, S.; Petersen, G. N.; Thordarson, T.; Pedersen, G. B.; Riishuus, M. S.

    2015-12-01

    The potential impact of a volcanic eruption is highly dependent on its eruption rate. In explosive eruptions ash may pose an aviation hazard that can extend several thousand kilometers away from the volcano. Models of ash dispersion depend on estimates of the volcanic source, but such estimates are prone to high error margins. Recent explosive eruptions, including the 2010 eruption of Eyjafjallajökull in Iceland, have provided a wealth of data that can help in narrowing these error margins. Within the EU-funded FUTUREVOLC project, a multi-parameter system is currently under development, based on an array of ground and satellite-based sensors and models to estimate mass eruption rates in explosive eruptions in near-real time. Effusive eruptions are usually considered less of a hazard as lava flows travel slower than eruption clouds and affect smaller areas. However, major effusive eruptions can release large amounts of SO2 into the atmosphere, causing regional pollution. In very large effusive eruptions, hemispheric cooling and continent-scale pollution can occur, as happened in the Laki eruption in 1783 AD. The Bárdarbunga-Holuhraun eruption in 2014-15 was the largest effusive event in Iceland since Laki and at times caused high concentrations of SO2. As a result civil protection authorities had to issue warnings to the public. Harmful gas concentrations repeatedly persisted for many hours at a time in towns and villages at distances out to 100-150 km from the vents. As gas fluxes scale with lava fluxes, monitoring of eruption rates is therefore of major importance to constrain not only lava but also volcanic gas emissions. This requires repeated measurements of lava area and thickness. However, most mapping methods are problematic once lava flows become very large. Satellite data on thermal emissions from eruptions have been used with success to estimate eruption rate. SAR satellite data holds potential in delivering lava volume and eruption rate estimates

  12. Flux Cancelation: The Key to Solar Eruptions

    NASA Technical Reports Server (NTRS)

    Panesar, Navdeep K.; Sterling, Alphonse; Moore, Ronald; Chakrapani, Prithi; Innes, Davina; Schmit, Don; Tiwari, Sanjiv

    2017-01-01

    Solar coronal jets are magnetically channeled eruptions that occur in all types of solar environments (e.g. active regions, quiet-Sun regions and coronal holes). Recent studies show that coronal jets are driven by the eruption of small-scare filaments (minifilaments). Once the eruption is underway magnetic reconnection evidently makes the jet spire and the bright emission in the jet base. However, the triggering mechanism of these eruptions and the formation mechanism of the pre-jet minifilaments are still open questions. In this talk, mainly using SDO/AIA (Solar Dynamics Observatory / Atmospheric Imaging Assembly) and SDO/HIM (Solar Dynamics Observatory / Helioseismic and Magnetic Imager) data, first I will address the question: what triggers the jet-driving minifilament eruptions in different solar environments (coronal holes, quiet regions, active regions)? Then I will talk about the magnetic field evolution that produces the pre-jet minifilaments. By examining pre-jet evolutionary changes in line-of-sight HMI magnetograms while examining concurrent EUV (Extreme Ultra-Violet) images of coronal and transition-region emission, we find clear evidence that flux cancelation is the main process that builds pre-jet minifilaments, and is also the main process that triggers the eruptions. I will also present results from our ongoing work indicating that jet-driving minifilament eruptions are analogous to larger-scare filament eruptions that make flares and CMEs (Coronal Mass Ejections). We find that persistent flux cancellation at the neutral line of large-scale filaments often triggers their eruptions. From our observations we infer that flux cancelation is the fundamental process from the buildup and triggering of solar eruptions of all sizes.

  13. Flux Cancelation: The Key to Solar Eruptions

    NASA Technical Reports Server (NTRS)

    Panesar, Navdeep K.; Sterling, Alphonse; Moore, Ronald; Chakrapani, Prithi; Innes, Davina; Schmit, Don; Tiwari, Sanjiv

    2017-01-01

    Solar coronal jets are magnetically channeled eruptions that occur in all types of solar environments (e.g. active regions, quiet-Sun regions and coronal holes). Recent studies show that coronal jets are driven by the eruption of small-scare filaments (minifilaments). Once the eruption is underway magnetic reconnection evidently makes the jet spire and the bright emission in the jet base. However, the triggering mechanism of these eruptions and the formation mechanism of the pre-jet minifilaments are still open questions. In this talk, mainly using SDOAIA and SDOHIM data, first I will address the question: what triggers the jet-driving minifilament eruptions in different solar environments (coronal holes, quiet regions, active regions)? Then I will talk about the magnetic field evolution that produces the pre-jet minifilaments. By examining pre-jet evolutionary changes in line-of-sight HMI magnetograms while examining concurrent EUV images of coronal and transition-region emission, we find clear evidence that flux cancelation is the main process that builds pre-jet minifilaments, and is also the main process that triggers the eruptions. I will also present results from our ongoing work indicating that jet-driving minifilament eruptions are analogous to larger-scare filament eruptions that make flares and CMEs. We find that persistent flux cancellation at the neutral line of large-scale filaments often triggers their eruptions. From our observations we infer that flux cancelation is the fundamental process from the buildup and triggering of solar eruptions of all sizes.

  14. Flux Cancelation: The Key to Solar Eruptions

    NASA Technical Reports Server (NTRS)

    Panesar, Navdeep K.; Sterling, Alphonse; Moore, Ronald; Chakrapani, Prithi; Innes, Davina; Schmit, Don; Tiwari, Sanjiv

    2017-01-01

    Solar coronal jets are magnetically channeled eruptions that occur in all types of solar environments (e.g. active regions, quiet-Sun regions and coronal holes). Recent studies show that coronal jets are driven by the eruption of small-scale filaments (minifilaments). Once the eruption is underway magnetic reconnection evidently makes the jet spire and the bright emission in the jet base. However, the triggering mechanism of these eruptions and the formation mechanism of the pre-jet minifilaments are still open questions. In this talk, mainly using SDO/AIA and SDO/HMI data, first I will address the question: what triggers the jet-driving minifilament eruptions in different solar environments (coronal holes, quiet regions, active regions)? Then I will talk about the magnetic field evolution that produces the pre-jet minifilaments. By examining pre-jet evolutionary changes in line-of-sight HMI magnetograms while examining concurrent EUV images of coronal and transition-region emission, we find clear evidence that flux cancellation is the main process that builds pre-jet minifilaments, and is also the main process that triggers the eruptions. I will also present results from our ongoing work indicating that jet-driving minifilament eruptions are analogous to larger-scale filament eruptions that make flares and CMEs. We find that persistent flux cancellation at the neutral line of large-scale filaments often triggers their eruptions. From our observations we infer that flux cancellation is the fundamental process for the buildup and triggering of solar eruptions of all sizes.

  15. Teeth

    MedlinePlus

    ... side effect of Dilantin seizure medication. Regular dental cleanings (prophylaxis) are a great help in controlling these. Example of a gingival fibroma. Fluoride The mouth can be a source of bacteria and potential infection. The care to maintain the ...

  16. Personalized Orthodontic Accurate Tooth Arrangement System with Complete Teeth Model.

    PubMed

    Cheng, Cheng; Cheng, Xiaosheng; Dai, Ning; Liu, Yi; Fan, Qilei; Hou, Yulin; Jiang, Xiaotong

    2015-09-01

    The accuracy, validity and lack of relation information between dental root and jaw in tooth arrangement are key problems in tooth arrangement technology. This paper aims to describe a newly developed virtual, personalized and accurate tooth arrangement system based on complete information about dental root and skull. Firstly, a feature constraint database of a 3D teeth model is established. Secondly, for computed simulation of tooth movement, the reference planes and lines are defined by the anatomical reference points. The matching mathematical model of teeth pattern and the principle of the specific pose transformation of rigid body are fully utilized. The relation of position between dental root and alveolar bone is considered during the design process. Finally, the relative pose relationships among various teeth are optimized using the object mover, and a personalized therapeutic schedule is formulated. Experimental results show that the virtual tooth arrangement system can arrange abnormal teeth very well and is sufficiently flexible. The relation of position between root and jaw is favorable. This newly developed system is characterized by high-speed processing and quantitative evaluation of the amount of 3D movement of an individual tooth.

  17. Endodontic regeneration and tooth revitalization in immature infected sheep teeth.

    PubMed

    Altaii, M; Cathro, P; Broberg, M; Richards, L

    2017-05-01

    To examine the response of immature sheep teeth with infected root canal systems to a commonly used pulp regeneration/revitalization protocol. Immature mandibular right first incisors in four sheep were mechanically exposed and the pulps infected. The mandibular left first incisors remained intact as controls. Five weeks later, the experimental root canals were chemo-mechanically cleaned and dressed with a triple-antibiotic paste for 4 weeks, before bleeding was induced inside the canal by mechanically irritating the periapical tissues. A collagen dressing was packed coronally onto the blood clot and the canal orifice sealed with mineral trioxide aggregate and glass ionomer cement. Six months later, the mandibles were collected and the teeth with associated periapical tissues were analysed radiographically, with CT scanning, and by histology. The changes in root length, dentine thickness in the apical third (mesially and distally), and apical diameter were analysed using Student's t-test. Radiographs revealed significant increases in root length, root wall thickness and narrowing of the apical diameter of the canals after treatment (P < 0.05), with no significant differences in root diameters found between the experimental and the control teeth (P > 0.05) on both radiographic and CT results. Root maturation and thickening of the walls due to hard tissue deposition was confirmed by histology in all experimental teeth. Hard tissues in the apical portion of the root were more developed than in the coronal portion. Endodontic regeneration and tooth revitalization procedures in immature infected sheep teeth showed positive outcomes with similar increases in root length and development to the control teeth. © 2016 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  18. Electrical activity during the 2006 Mount St. Augustine volcanic eruptions

    USGS Publications Warehouse

    Thomas, Ronald J.; Krehbiel, Paul R.; Rison, William; Edens, H. E.; Aulich, G. D.; McNutt, S.R.; Tytgat, Guy; Clark, E.

    2007-01-01

    By using a combination of radio frequency time-of-arrival and interferometer measurements, we observed a sequence of lightning and electrical activity during one of Mount St. Augustine's eruptions. The observations indicate that the electrical activity had two modes or phases. First, there was an explosive phase in which the ejecta from the explosion appeared to be highly charged upon exiting the volcano, resulting in numerous apparently disorganized discharges and some simple lightning. The net charge exiting the volcano appears to have been positive. The second phase, which followed the most energetic explosion, produced conventional-type discharges that occurred within plume. Although the plume cloud was undoubtedly charged as a result of the explosion itself, the fact that the lightning onset was delayed and continued after and well downwind of the eruption indicates that in situ charging of some kind was occurring, presumably similar in some respects to that which occurs in normal thunderstorms.

  19. Radiographic visualization of magma dynamics in an erupting volcano

    PubMed Central

    Tanaka, Hiroyuki K. M.; Kusagaya, Taro; Shinohara, Hiroshi

    2014-01-01

    Radiographic imaging of magma dynamics in a volcanic conduit provides detailed information about ascent and descent of magma, the magma flow rate, the conduit diameter and inflation and deflation of magma due to volatile expansion and release. Here we report the first radiographic observation of the ascent and descent of magma along a conduit utilizing atmospheric (cosmic ray) muons (muography) with dynamic radiographic imaging. Time sequential radiographic images show that the top of the magma column ascends right beneath the crater floor through which the eruption column was observed. In addition to the visualization of this magma inflation, we report a sequence of images that show magma descending. We further propose that the monitoring of temporal variations in the gas volume fraction of magma as well as its position in a conduit can be used to support existing eruption prediction procedures. PMID:24614612

  20. Dome forming eruptions: a global hazards database

    NASA Astrophysics Data System (ADS)

    Ogburn, S. E.; Loughlin, S.; Calder, E. S.; Ortiz, N.

    2009-12-01

    The analysis of global datasets of historical eruptions is a powerful tool for decision-making as well as for scientific discovery. Lava dome forming eruptions are common throughout the world, can extend for significant periods of time and have many associated hazards, thus providing a rich source of data to mine. A database on dome forming eruptions is under development with the view to aiding comparative studies, providing scientists with valuable data for analysis, and enabling advances in modeling of associated hazards. For new eruptive episodes in particular, and in the absence of monitoring data or a knowledge of a volcano’s eruptive history, global analysis can provide a method of understanding what might be expected based on similar eruptions in the past. Important scientific information has already been gleaned from disparate collections of dome-forming eruption hazard information, such as variation in the mobility of different types of pyroclastic flows, magma ascent and extrusion dynamics, and mechanisms of lava dome collapse. Further, modeling (both empirically-based and geophysically-based) of volcanic phenomena requires extensive data for development, calibration and validation. This study investigates the relationship between large explosive eruptions (VEI ≥ 4) and lava dome-growth from 1000 CE to present by development of a world-wide database of all relevant information, including dome growth duration, pauses between episodes of dome growth, and extrusion rates. Data sources include the database of volcanic activity maintained by the Smithsonian Institute (Global Volcanism Program) and all relevant published review papers, research papers and reports. For example, nearly all dome-forming eruptions have been associated with some level of explosive activity. Most explosions are vulcanian with eruption plumes reaching less than 15 km, and with a Volcanic Explosivity Index (VEI) <3. However large Plinian explosions with a VEI ≥ 4 can also occur

  1. Thermal vesiculation during volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Lavallée, Yan; Dingwell, Donald B.; Johnson, Jeffrey B.; Cimarelli, Corrado; Hornby, Adrian J.; Kendrick, Jackie E.; von Aulock, Felix W.; Kennedy, Ben M.; Andrews, Benjamin J.; Wadsworth, Fabian B.; Rhodes, Emma; Chigna, Gustavo

    2015-12-01

    Terrestrial volcanic eruptions are the consequence of magmas ascending to the surface of the Earth. This ascent is driven by buoyancy forces, which are enhanced by bubble nucleation and growth (vesiculation) that reduce the density of magma. The development of vesicularity also greatly reduces the ‘strength’ of magma, a material parameter controlling fragmentation and thus the explosive potential of the liquid rock. The development of vesicularity in magmas has until now been viewed (both thermodynamically and kinetically) in terms of the pressure dependence of the solubility of water in the magma, and its role in driving gas saturation, exsolution and expansion during decompression. In contrast, the possible effects of the well documented negative temperature dependence of solubility of water in magma has largely been ignored. Recently, petrological constraints have demonstrated that considerable heating of magma may indeed be a common result of the latent heat of crystallization as well as viscous and frictional heating in areas of strain localization. Here we present field and experimental observations of magma vesiculation and fragmentation resulting from heating (rather than decompression). Textural analysis of volcanic ash from Santiaguito volcano in Guatemala reveals the presence of chemically heterogeneous filaments hosting micrometre-scale vesicles. The textures mirror those developed by disequilibrium melting induced via rapid heating during fault friction experiments, demonstrating that friction can generate sufficient heat to induce melting and vesiculation of hydrated silicic magma. Consideration of the experimentally determined temperature and pressure dependence of water solubility in magma reveals that, for many ascent paths, exsolution may be more efficiently achieved by heating than by decompression. We conclude that the thermal path experienced by magma during ascent strongly controls degassing, vesiculation, magma strength and the effusive

  2. Thermal vesiculation during volcanic eruptions.

    PubMed

    Lavallée, Yan; Dingwell, Donald B; Johnson, Jeffrey B; Cimarelli, Corrado; Hornby, Adrian J; Kendrick, Jackie E; von Aulock, Felix W; Kennedy, Ben M; Andrews, Benjamin J; Wadsworth, Fabian B; Rhodes, Emma; Chigna, Gustavo

    2015-12-24

    Terrestrial volcanic eruptions are the consequence of magmas ascending to the surface of the Earth. This ascent is driven by buoyancy forces, which are enhanced by bubble nucleation and growth (vesiculation) that reduce the density of magma. The development of vesicularity also greatly reduces the 'strength' of magma, a material parameter controlling fragmentation and thus the explosive potential of the liquid rock. The development of vesicularity in magmas has until now been viewed (both thermodynamically and kinetically) in terms of the pressure dependence of the solubility of water in the magma, and its role in driving gas saturation, exsolution and expansion during decompression. In contrast, the possible effects of the well documented negative temperature dependence of solubility of water in magma has largely been ignored. Recently, petrological constraints have demonstrated that considerable heating of magma may indeed be a common result of the latent heat of crystallization as well as viscous and frictional heating in areas of strain localization. Here we present field and experimental observations of magma vesiculation and fragmentation resulting from heating (rather than decompression). Textural analysis of volcanic ash from Santiaguito volcano in Guatemala reveals the presence of chemically heterogeneous filaments hosting micrometre-scale vesicles. The textures mirror those developed by disequilibrium melting induced via rapid heating during fault friction experiments, demonstrating that friction can generate sufficient heat to induce melting and vesiculation of hydrated silicic magma. Consideration of the experimentally determined temperature and pressure dependence of water solubility in magma reveals that, for many ascent paths, exsolution may be more efficiently achieved by heating than by decompression. We conclude that the thermal path experienced by magma during ascent strongly controls degassing, vesiculation, magma strength and the effusive

  3. Reasons for and patterns relating to the extraction of permanent teeth in a subset of the Saudi population.

    PubMed

    Alesia, Khalil; Khalil, Hesham S

    2013-01-01

    The purpose of this study was to investigate the reasons for and patterns of extraction of permanent teeth in a subset of the Saudi population. During a 3-month period, dentists were asked to record, using a specially designed survey form, the reasons for every extraction of a permanent tooth. The reasons for tooth extraction were assigned to different causes, ie, dental caries, periodontal disease, eruption problems, trauma, orthodontics, failed root canal treatment, and others. The data requested for each extraction were: patient age, gender, nationality, and type of tooth removed and the reason for its extraction. The highest percentage of extractions was observed in young females aged 10-30 years. Presence of caries was observed to be the main reason for extraction (50.2%) followed by orthodontic problems (18.2%), eruption problems (17.5%), and periodontal problems (8.2%). The most frequently extracted posterior teeth were the third mandibular molar (19.4%), the third maxillary molar (16.4%), the first maxillary premolar (13.2%), and the first mandibular molar (10.9%). Dental caries was found to be the most common reason for extraction of teeth. Molar teeth were found to be the most frequently extracted, with an increased number of extracted first premolars as a result of orthodontic treatment. The highest percentage of extractions was observed in young females aged 10-30 years.

  4. Reasons for and patterns relating to the extraction of permanent teeth in a subset of the Saudi population

    PubMed Central

    Alesia, Khalil; Khalil, Hesham S

    2013-01-01

    Background The purpose of this study was to investigate the reasons for and patterns of extraction of permanent teeth in a subset of the Saudi population. Methods During a 3-month period, dentists were asked to record, using a specially designed survey form, the reasons for every extraction of a permanent tooth. The reasons for tooth extraction were assigned to different causes, ie, dental caries, periodontal disease, eruption problems, trauma, orthodontics, failed root canal treatment, and others. The data requested for each extraction were: patient age, gender, nationality, and type of tooth removed and the reason for its extraction. Results The highest percentage of extractions was observed in young females aged 10–30 years. Presence of caries was observed to be the main reason for extraction (50.2%) followed by orthodontic problems (18.2%), eruption problems (17.5%), and periodontal problems (8.2%). The most frequently extracted posterior teeth were the third mandibular molar (19.4%), the third maxillary molar (16.4%), the first maxillary premolar (13.2%), and the first mandibular molar (10.9%). Conclusion Dental caries was found to be the most common reason for extraction of teeth. Molar teeth were found to be the most frequently extracted, with an increased number of extracted first premolars as a result of orthodontic treatment. The highest percentage of extractions was observed in young females aged 10–30 years. PMID:23986651

  5. Caries, Periodontal Disease, Supernumerary Teeth and Other Dental Disorders in Swedish Wild Boar (Sus scrofa).

    PubMed

    Malmsten, A; Dalin, A-M; Pettersson, A

    2015-07-01

    Between January and December 2013, the dental and periodontal health of 99 Swedish wild boars (Sus scrofa) was investigated. Sampling occurred in conjunction with routine hunting at six large estates in the southern and middle parts of Sweden. All six of the estates use supplemental feeding. The weight of the animals, their sex and their dates of death were noted. Age was estimated using tooth eruption and tooth replacement patterns. The oral cavity was inspected and abnormalities were recorded on a dental chart modified for wild boars. The findings included supernumerary teeth, absence of teeth, mild class II malocclusion, severe tooth wear, periodontitis, calculus, caries, tooth fractures and the presence of enamel defects. Swedish wild boars suffer from different dental lesions and the impact of supplemental feeding on dental and periodontal health is still to be investigated. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Multiple coincident eruptive seismic tremor sources during the 2014-2015 eruption at Holuhraun, Iceland

    NASA Astrophysics Data System (ADS)

    Eibl, Eva P. S.; Bean, Christopher J.; Jónsdóttir, Ingibjörg; Höskuldsson, Armann; Thordarson, Thorvaldur; Coppola, Diego; Witt, Tanja; Walter, Thomas R.

    2017-04-01

    We analyze eruptive tremor during one of the largest effusive eruptions in historical times in Iceland (2014/2015 Holuhraun eruption). Seismic array recordings are compared with effusion rates deduced from Moderate Resolution Imaging Spectroradiometer recordings and ground video monitoring data and lead to the identification of three coexisting eruptive tremor sources. This contrasts other tremor studies that generally link eruptive tremor to only one source usually associated with the vent. The three sources are (i) a source that is stable in back azimuth and shows bursts with ramp-like decrease in amplitude at the beginning of the eruption: we link it to a process below the open vents where the bursts correlate with the opening of new vents and temporary increases in the lava fountaining height; (ii) a source moving by a few degrees per month while the tremor amplitude suddenly increases and decreases: back azimuth and slowness correlate with the growing margins of the lava flow field, whilst new contact with a river led to fast increases of the tremor amplitude; and (iii) a source moving by up to 25° southward in 4 days that cannot be related to any observed surface activity and might be linked to intrusions. We therefore suggest that eruptive tremor amplitudes/energies are used with caution when estimating eruptive volumes, effusion rates, or the eruption explosivity as multiple sources can coexist during the eruption phase. Our results suggest that arrays can monitor both the growth of a lava flow field and the activity in the vents.

  7. Application of computed tomography for supernumerary teeth location in pediatric dentistry.

    PubMed

    Raupp, Suziane; Kramer, Paulo Floriani; de Oliveira, Helena Willhelm; da Rosa, Francinne Miranda; Faraco, Italo Medeiros

    2008-01-01

    Conventional radiographs provide bi-dimensional images of three-dimensional structures limiting optimal treatment planning. To overcome this deficiency, Computed Tomography (CT) has been used as a diagnostic method in Medicine and Dentistry. CT allows for supernumerary teeth location, the establishment of positional relations with other teeth, and the assessment of surrounding bone thickness; thus, facilitating surgical access and technique choice while reducing the procedure time, of great importance in pediatric dental care. The aim of this study was to present the possibility of applying CT for supernumerary teeth location, through the case report of a five-year-old female patient presenting two supernumerary teeth in the anterior palatal area. In conclusion, CT appears to be an excellent image diagnostic method for locating unerupted supernumerary teeth, providing precise information for planning and performing the surgical approach, while reducing operatory time and post-operatory complications; factors of extreme importance when treating young children.

  8. Clinical and radiographic sequelae to primary teeth affected by dental trauma: a 9-year retrospective study.

    PubMed

    Costa, Vanessa Polina Pereira; Goettems, Marilia Leão; Baldissera, Elaine Zanchin; Bertoldi, Andréa Dâmaso; Torriani, Dione Dias

    2016-08-18

    This retrospective study aimed at determining the predicted risks of clinical and radiographic complications in primary teeth following traumatic dental injuries, according to injury type, severity and child's age. Data were collected from records of children treated at a Dental Trauma Center in Brazil for nine years. Records of 576 children were included; clinical sequelae were assessed in 774 teeth, and radiographic sequelae, in 566 teeth. A total of 408 teeth (52.7%) had clinical sequelae and 185 teeth (32.7%), radiographic sequelae. The type of injury with the highest number of clinical sequelae was the crown-root fracture (86.4%). Clinical sequelae increased with injury severity (p < 0.001), whereas radiographic sequelae did not (0.236). The predicted risk of color change was 29.0% (95%CI 19-41) for teeth with enamel fracture, and 26.0% (95%CI 14-40) for teeth with enamel dentin fracture as well as enamel dentin pulp fracture. Risk of periapical radiolucency was higher for teeth with enameldentinpulp fracture (61.1% 95%CI 35-82) and those with subluxation (15.8% 95%CI 10-22). Risk of premature loss was 27.3% (95%CI 13-45) for teeth with extrusive luxation, and 10.2% (95%CI 5-17) for those with intrusive luxation. The assessment of predicted risks of sequelae showed that teeth with hard tissue trauma tended to present color change, periapical radiolucency and premature loss, whereas teeth with supporting tissue trauma showed color change, abnormal position, premature loss and periapical radiolucency as the most common sequelae. Knowledge about the predicted risks of complications may help clinicians establish appropriate treatment plans.

  9. Prevalence and management of natal/neonatal teeth in cleft lip and palate patients

    PubMed Central

    Yilmaz, R. Burcu Nur; Cakan, Derya Germec; Mesgarzadeh, Nasim

    2016-01-01

    Objective: The aim of this study was to determine the prevalence and distribution of natal/neonatal teeth in infants with cleft lip and palate (CLP) according to gender, involving jaw and side and to show the management of some cases. Materials and Methods: A retrospective study was carried out on medical history and photographic records of 69 infants with CLP, who were treated at the CLP clinic of Yeditepe University between years 2014–2015. The presence of neonatal teeth was determined, and if present the gender, type of cleft, and position were recorded. Statistical analysis was performed. Results: Neonatal teeth were observed in 7% of the study group. No significant differences were found between cleft types and gender (P > 0.05). The prevalence of neonatal teeth in bilateral, unilateral and isolated cleft type was 16.5%, 6.5%, and none, respectively. All neonatal teeth were located in the maxilla and on the cleft-side (100%). Conclusion: The presence of natal/neonatal teeth in infants with CLP was not rare. In all of these cases the teeth were located adjacent to the cleft region. In isolated palatal cleft, where the alveolar region including the teeth buds are away from the cleft, no neonatal teeth were observed. It may be concluded that neonatal teeth in infants with CLP are frequently present and located inside the borders of the presurgical orthopedic treatment (POT) plate. Therefore, if possible, immediate extraction of the neonatal teeth is advised or if not possible because of systemic health reasons, modifications of the plate are required. PMID:27011740

  10. Observed Aspects of Reconnection in Solar Eruptions

    NASA Technical Reports Server (NTRS)

    Moore, Ronald L.

    2010-01-01

    Signatures of reconnection in major CME (coronal mass ejection)/flare eruptions and in coronal X-ray jets are illustrated and interpreted. The signatures are magnetic field lines and their feet that brighten in flare emission. CME/flare eruptions are magnetic explosions in which: 1. The field that erupts is initially a closed arcade. 2. At eruption onset, most of the free magnetic energy to be released is not stored in field bracketing a current sheet, but in sheared field in the core of the arcade. 3. The sheared core field erupts by a process that from its start or soon after involves fast tether-cutting reconnection at an initially small current sheet low in the sheared core field. If the arcade has oppositely-directed field over it, the eruption process from its start or soon after also involves fast breakout reconnection at an initially small current sheet between the arcade and the overarching field. These aspects are shown by the small area of the bright field lines and foot-point flare ribbons in the onset of the eruption. 4. At either small current sheet, the fast reconnection progressively unleashes the erupting core field to erupt with progressively greater force. In turn, the erupting core field drives the current sheet to become progressively larger and to undergo progressively greater fast reconnection in the explosive phase of the eruption, and the flare arcade and ribbons grow to become comparable to the pre-eruption arcade in lateral extent. In coronal X-ray jets: 1. The magnetic energy released in the jet is built up by the emergence of a magnetic arcade into surrounding unipolar "open" field. 2. A simple jet is produced when a burst of reconnection occurs at the current sheet between the arcade and the open field. This produces a bright reconnection jet and a bright reconnection arcade that are both much smaller in diameter that the driving arcade. 3. A more complex jet is produced when the arcade has a sheared core field and undergoes an

  11. The dental cavities of equine cheek teeth: three-dimensional reconstructions based on high resolution micro-computed tomography.

    PubMed

    Kopke, Susan; Angrisani, Nina; Staszyk, Carsten

    2012-09-25

    Recent studies reported on the very complex morphology of the pulp system in equine cheek teeth. The continuous production of secondary dentine leads to distinct age-related changes of the endodontic cavity. Detailed anatomical knowledge of the dental cavities in all ages is required to explain the aetiopathology of typical equine endodontic diseases. Furthermore, data on mandibular and maxillary pulp systems is in high demand to provide a basis for the development of endodontic therapies. However, until now examination of the pulp cavity has been based on either sectioned teeth or clinical computed tomography. More precise results were expected by using micro-computed tomography with a resolution of about 0.1 mm and three-dimensional reconstructions based on previous greyscale analyses and histological verification. The aim of the present study was to describe the physiological configurations of the pulp system within a wide spectrum of tooth ages. Maxillary teeth: All morphological constituents of the endodontic cavity were present in teeth between 4 and 16 years: Triadan 06s displayed six pulp horns and five root canals, Triadan 07-10s five pulp horns and four root canals and Triadan 11s seven pulp horns and four to six root canals. A common pulp chamber was most frequent in teeth ≤5 years, but was found even in a tooth of 9 years. A large variety of pulp configurations was observed within 2.5 and 16 years post eruption, but most commonly a separation into mesial and distal pulp compartments was seen. Maxillary cheek teeth showed up to four separate pulp compartments but the frequency of two, three and four pulp compartments was not related to tooth age (P > 0.05). In Triadan 06s, pulp horn 6 was always connected to pulp horns 1 and 3 and root canal I. In Triadan 11s, pulp horns 7 and 8 were present in variable constitutions. Mandibular teeth: A common pulp chamber was present in teeth up to 15 years, but most commonly seen in teeth ≤5 years. A segmented

  12. The dental cavities of equine cheek teeth: three-dimensional reconstructions based on high resolution micro-computed tomography

    PubMed Central

    2012-01-01

    Background Recent studies reported on the very complex morphology of the pulp system in equine cheek teeth. The continuous production of secondary dentine leads to distinct age-related changes of the endodontic cavity. Detailed anatomical knowledge of the dental cavities in all ages is required to explain the aetiopathology of typical equine endodontic diseases. Furthermore, data on mandibular and maxillary pulp systems is in high demand to provide a basis for the development of endodontic therapies. However, until now examination of the pulp cavity has been based on either sectioned teeth or clinical computed tomography. More precise results were expected by using micro-computed tomography with a resolution of about 0.1 mm and three-dimensional reconstructions based on previous greyscale analyses and histological verification. The aim of the present study was to describe the physiological configurations of the pulp system within a wide spectrum of tooth ages. Results Maxillary teeth: All morphological constituents of the endodontic cavity were present in teeth between 4 and 16 years: Triadan 06s displayed six pulp horns and five root canals, Triadan 07-10s five pulp horns and four root canals and Triadan 11s seven pulp horns and four to six root canals. A common pulp chamber was most frequent in teeth ≤5 years, but was found even in a tooth of 9 years. A large variety of pulp configurations was observed within 2.5 and 16 years post eruption, but most commonly a separation into mesial and distal pulp compartments was seen. Maxillary cheek teeth showed up to four separate pulp compartments but the frequency of two, three and four pulp compartments was not related to tooth age (P > 0.05). In Triadan 06s, pulp horn 6 was always connected to pulp horns 1 and 3 and root canal I. In Triadan 11s, pulp horns 7 and 8 were present in variable constitutions. Mandibular teeth: A common pulp chamber was present in teeth up to 15 years, but most commonly seen in teeth ≤5

  13. Magma Chamber Creep and Repressurization Following Eruptions

    NASA Astrophysics Data System (ADS)

    Segall, P.

    2016-12-01

    Elevated temperature surrounding long-lived magma chambers leads to viscoelastic behavior of the surrounding crust, influencing surface deformation and potentially stress conditions for eruption onset. I analyze an approximate solution for a spherical magma chamber (radius ) surrounded by a spherical Maxwell viscoelastic shell (radius ) in an elastic half-space following a sudden decrease in chamber pressure. Mass flux into the chamber from deep source is proportional to difference between source and chamber pressures, . Solutions depend on , , where are the magma and chamber compressibilities, the relaxation time , and the characteristic recharge time for the fully elastic system, . In the no-recharge limit () the system exhibits either post-eruptive deflation or, for sufficiently incompressible magmas, partial reinflation. More generally immediate post eruptive inflation is favored by large and small . For elastic behavior the magma pressure recovers on a time scale , where is the coeruptive pressure drop. For this time increases by factors of up to 2.5, particularly for large ; post-eruptive creep increases the chamber pressure, thus decreasing the pressure gradient driving recharge, ultimately delaying pressure recovery. Following eruption the hoop stresses, which are initially compressive, relax toward the radial stress which causes them to go through a local (relative tension) maximum on a time scale . The magma pressure in excess of the dike normal compression at the chamber wall, can recover to pre-eruptive values well before the chamber pressure orerupted mass, has recovered. This suggests that dikes could nucleate at the chamber margin well before sufficient pressure has recovered to drive them to the earth's surface. Recovery of magma overpressure relative to hoop stress in the elastic region to pre-eruptive values is assumed to be a sufficient condition for subsequent eruption. Interestingly, for some parameters the surface deformation can take as much

  14. [Esthetic restorations of primary anterior teeth].

    PubMed

    Elqadir, A Jamil; Shapira, J; Ziskind, K; Ram, D

    2013-04-01

    Esthetic treatment of primary teeth is one of the greatest challenges to pediatric dentists. A variety of restorative options using full coverage are available for anterior primary teeth. In the last half century the emphasis on treatment of severely decayed primary teeth shifted from extraction to restoration. In the past, restorations consisted of placement of stainless steel crowns on severely decayed teeth. However, they are esthetically unacceptable today. Over the last decade parents expect a higher esthetic standard for their children's primary teeth. Thus, the restoration should provide esthetic appearance and durability in addition to restoring function. The purpose of this review is to describe the types of full coverage options for anterior primary teeth currently available.

  15. [Structuralization of a human teeth bank].

    PubMed

    Nassif, Alessandra Cristina da Silva; Tieri, Fabio; da Ana, Patricia Aparecida; Botta, Sérgio Brossi; Imparato, José Carlos Pettorossi

    2003-05-01

    A Human Teeth Bank (HTB) is a nonprofit institution, associated to a college, to a university or to some other institution. Its purpose is to fulfill academic needs, by supplying human teeth for research or for preclinical laboratory training of students, thus eliminating the illegal commerce of teeth that still takes place in dental schools. It is also up to an HTB to work for the elimination of cross-infection caused by indiscriminate handling of extracted teeth. In order to work properly, an HTB should have a strict control of its internal procedures, which include separation and stocking of teeth, as well as an appropriate maintaining of donors' and beneficiaries' records. In this article, we discuss the functions that an HTB can perform, and how the Human Teeth Bank, School of Dentistry, University of S o Paulo, works and organizes itself today.

  16. Forecasting volcanic eruptions: the narrow margin between eruption and intrusion

    NASA Astrophysics Data System (ADS)

    Steele, Alexander; Kilburn, Christopher; Wall, Richard; Charlton, Danielle

    2016-04-01

    Volcano-tectonic (VT) seismicity is one of the primary geophysical signals for monitoring volcanic unrest. It measures the brittle response of the crust to changes in stress and provides a natural proxy for gauging the stability of a pressurizing body of magma. Here we apply a new model of crustal extension to observations from the 2015 unrest of Cotopaxi, in Ecuador. The model agrees well with field data and is consistent with accelerating unrest during the pressurization and rupture of a vertically-extended magma source within the volcanic edifice. At andesitic-dacitic stratovolcanoes in subduction zones, unrest after long repose is often characterised by increases in VT event rate that change from an exponential to hyperbolic trend with time. This sequence was observed when renewed unrest was detected in April 2015 at Cotopaxi, following at least 73 years of repose. After about 80 days of elevated seismicity at an approximately steady rate, the numbers of VT events increased exponentially with time for c. 80 days, before increasing for c. 15 days along a faster, hyperbolic trend. Both trends were characterised by the same value of 2 for the ratio of maximum applied stress SF to tensile strength of the crust σT, consistent with the pressurization of an approximately vertical, cylindrical magma body. The hyperbolic trend indicated a potential rupture on 25 September. Rupture appears to have occurred on 21-22 September, when the VT rate rapidly decreased. However, no major eruption accompanied the change, suggesting that a near-surface intrusion occurred instead. Although the quantitative VT trends were consistent with the rupture of a magmatic body, they could not on their own distinguish between an eruptive or intrusive outcome. An outstanding goal remains to identify additional precursory characteristics for quantifying the probability that magma will reach the surface after escaping from a ruptured parent body. Data for this analysis were kindly made available

  17. 3 Dimensional Diagnosis Unravelling Prognosis of Multiple Impacted Teeth – A Case Report

    PubMed Central

    Gopinath, Adusumilli; Reddy, Naveen Admala; Rohra, Mayur G

    2013-01-01

    Impaction of teeth results from the interplay between nature and nurture. Radiographs play an important role in assessment of both the location and the typing of impacted teeth. In general, periapical, occlusal, and/or panoramic radiographs are sufficient for providing the information required by the clinician. Recent advances in diagnostic imaging enables to visualize , diagnose and prognose the treatment outcome of the impacted teeth. This case report discusses the value of cone beam computerized tomography (CBCT) for evaluation of the critical parameters like bone thickness , tooth position and tooth morphology of multiple impacted teeth by 3 dimensional radiography – CBCT. In this report, we present a case of 27-year-old male patient with multiple missing teeth. Radiographs revealed multiple impacted permanent teeth, though medical and family history along with physical examination was not suggestive of any syndromes. Intraoral periapical radiograph, Orthopantomograph, Occlusal radiograph, Cone beam computed tomography were taken for the same patient to determine the exact position of multiple impacted teeth and prognose the treatment plan with the associated factors to impacted teeth. Cone beam computed tomography is an accurate modality to localize and determine the prognosing factors associated with multiple impacted teeth. Three-dimensional volumetric imaging might provide information for improved diagnosis and treatment plans, and ultimately result in more successful treatment outcomes and better care for patients. How to cite this article: Gopinath A, Reddy NA, Rohra MG. 3 Dimensional Diagnosis Unravelling Prognosis of Multiple Impacted Teeth – A Case Report. J Int Oral Health 2013; 5(4):78-83. PMID:24155625

  18. Spectrophotometric Evolution of Eta Carinae's Great Eruption

    NASA Astrophysics Data System (ADS)

    Rest, Armin; Prieto, Jose Luis; Bianco, Federica; Matheson, Thomas; Smith, Nathan; Smith, Chris; Chornock, Ryan; Sinnott, Brendan; Welch, Douglas; Walborn, Nolan

    2013-06-01

    Eta Carinae is one of the most massive binaries in the Milky Way, and its expanding circumstellar nebula has been studied in detail. It was seen as the second brightest star in the sky during its 1800s "Great Eruption", but only visual estimates of its brightness were recorded. We discovered light echoes of the Great Eruption, which allowed us to obtain a spectrum of this event now, 150 years after it was first observed. We will present our new follow-up observations with which we have started to retrace its spectrophotometric evolution during and before the eruption.

  19. Carious deciduous teeth are a potential source for dental pulp stem cells.

    PubMed

    Werle, Stefanie Bressan; Lindemann, Daniele; Steffens, Daniela; Demarco, Flávio Fernando; de Araujo, Fernando Borba; Pranke, Patrícia; Casagrande, Luciano

    2016-01-01

    The objectives of this study are to isolate, cultivate, and characterize stem cells from the pulp of carious deciduous teeth (SCCD) and compare them to those retrieved from sound deciduous teeth (SHED--stem cells from human exfoliated deciduous teeth). Cells were obtained of dental pulp collected from sound (n = 10) and carious (n = 10) deciduous human teeth. Rate of isolation, proliferation assay (0, 1, 3, 5, and 7 days), STRO-1, mesenchymal (CD29, CD73, and CD90) and hematopoietic surface marker expression (CD14, CD34, CD45, HLA-DR), and differentiation capacity were evaluated. Isolation success rates were 70 and 80 % from the carious and sound groups, respectively. SCCD and SHED presented similar proliferation rate. There were no statistical differences between the groups for the tested surface markers. The cells from sound and carious deciduous teeth were positive for CD29, CD73, and CD90 and negative for CD14, CD34, CD45, and HLA-DR and were capable of differentiating into osteogenic, chondrogenic, and adipogenic lineages. SCCD demonstrated a similar pattern of proliferation, immunophenotypical characteristics, and differentiation ability as those obtained from sound deciduous teeth. These SCCD represent a feasible source of stem cells. Decayed deciduous teeth have been usually discarded once the pulp tissue could be damaged and the activity of stem cells compromised. These findings show that stem cells from carious deciduous teeth can be applicable source for cell-based therapies in tissue regeneration.

  20. Tooth Sensitivity in Fluorotic Teeth

    PubMed Central

    Tonguc, Mine Ozturk; Ozat, Yener; Sert, Tugba; Sonmez, Yonca; Kirzioglu, F. Yesim

    2011-01-01

    Objectives: The aim of this study was to compare the demographic and clinical features of tooth sensitivity (TS) in subjects with and without fluorosis. Methods: A total of 2249 subjects (378 subjects with fluorosis and 1871 subjects without fluorosis) were examined for TS during a study period of one year and TS was determined in 122 subjects. The level of TS was evaluated on a visual analogue scale (VAS). The sensitivity evaluation was made by applying tactile and cold air stimuli. In teeth sensitive to any stimuli, the plaque index (PI), gingival index (GI), gingival recession (GR) and periodontal pocket depth (PPD) were recorded. Fluorosis was assessed using the Dean Index. Results: One hundred and twenty-two participants were found to have TS (5.42%). The frequency of TS in subjects with fluorosis was 9.26%, while the frequency of TS in subjects without fluorosis was 4.65%. There was a statistically significant difference between the groups in terms of TS frequency (P=0.0003). In contrast, there were no significant differences between the groups for periodontal parameters except PI. Conclusions: The results of the study showed that the subjects with fluorosis may have been suffering from TS more than the subjects with normal dentition. Further studies are necessary to determine the factors that contribute to sensitivity of teeth with fluorosis. PMID:21769268

  1. Challenging parents' myths regarding their children's teething.

    PubMed

    Owais, A I; Zawaideh, F; Al-Batayneh, O B

    2010-02-01

    The aims of this study were to (i) investigate the parental beliefs about teething signs and symptoms, (ii) investigate the parents' practices used to alleviate teething troubles and (iii) provide an educational basis for dental healthcare providers to better educate parents on this subject. A cross-sectional survey was conducted in a random sample of 1500 parents attending Maternity and Child Health Care Centers. The self-administered questionnaire contained three sections: Section I surveyed parents' and their children's demographic characteristics, Section II aimed to assess the general knowledge and beliefs of parents regarding their children's teething. Section III aimed at investigating the practices that the parents would do to manage teething problems and relieve pain. The analysis of data was carried out using spss computer software. Descriptive statistics and Chi-squared test were utilized. Almost 75% of the participants incorrectly attributed fever, diarrhoea and sleep disturbances to teething, and more than 50% believed systemic symptoms are not related to the process. More than 50% of the participants allowed their children to bite on chilled objects, (76.1%) used systemic analgesics and (65.6%) rubbed the gums with topical analgesics to relieve the symptoms associated with teething. This study shows a common lack of knowledge about teething among parents. Parents should be better educated about the teething process and the proper management of teething troubles by the dental health care providers.

  2. Early headgear effect on the eruption pattern of maxillary second molars.

    PubMed

    Abed, Yossi; Brin, Ilana

    2010-07-01

    To test the hypothesis that the use of a combination headgear (HG) during the first phase of orthodontic treatment has no effect on the eruption pattern of the maxillary second permanent molars. The records of the patients in a two-phase randomized clinical trial of early Class II treatment were utilized. The HG group comprised 47 patients, and the control (CON) group comprised 52 patients. The mean age of both groups was 9.4 years at the beginning of the clinical trial (T1). Cephalograms and panoramic views obtained at T1 and at the end of 15 months of phase I treatment or observation (T2) were utilized. The vertical and horizontal movements of the first and second upper molars (U6 and U7, respectively) were measured. The beginning of phase II (T3) and the end of phase II (T4) records were visually reviewed for follow-up of the eruption of the U7. The pattern of movement for the distal and vertical displacement of the U6 and U7 was significantly different in the HG and CON groups (P < .001). At the end of phase I, none of the U7 in either group were diagnosed as malposed or suspected for impaction. At the end of phase II, all but one U7 with a possible cystic lesion had erupted. The hypothesis is rejected. Forces exerted by combination headgear to the U6 in phase I have a distalizing effect and a transitory slowing down effect on the eruption of the U7 buds. These latter teeth always erupted except when pathology occurred.

  3. Explosive eruptive activity and temporal magmatic changes at Yotei Volcano during the last 50,000 years, southwest Hokkaido, Japan

    NASA Astrophysics Data System (ADS)

    Uesawa, Shimpei; Nakagawa, Mitsuhiro; Umetsu, Akane

    2016-10-01

    To understand the eruptive history, structure, and magmatic evolution of Yotei Volcano, southwest Hokkaido, Japan, we investigated the geology and petrology of tephras located around the base of the volcano. We identified 43 tephra units interbedded with soils (in descending stratigraphic order, tephras Y1-Y43), and four widespread regional tephras. Ten radiocarbon ages were obtained from soils beneath the Yotei tephras. On the basis of petrologic differences and, the stratigraphic positions of thick layers of volcanic ash soil, indicative of volcanic stratigraphic gaps, the Yotei tephras are divided into four groups (in ascending stratigraphic order): Yotei tephra groups I, II-1, II-2, and II-3. We calculated the age of each eruptive deposit based on the soil accumulation rate, and estimated the volume of each eruption using isopach maps or the correlation between eruption volume and the maximum thickness at ~ 10 km from the summit crater. The results regarding eruptive activity and the rate of explosive eruptions indicate four eruptive stages at Yotei Volcano over the last 50,000 years. Stage I eruptions produced Yotei tephra group I between ca. 54 cal. ka BP and up to at least ca. 46 cal. ka BP, at relatively high average eruption rates of 0.07 km3 dense-rock equivalent (DRE)/ky. After a pause in activity of ca. 8000 years, Stage II-1 to II-2 eruptions produced Yotei tephra groups II-1 and II-2 from ca. 38 to ca. 21 cal. ka BP at high average eruption rates (0.10 km3 DRE/ky), after a pause in activity of 2000-3000 years. Finally, after another pause in activity of 4000-5000 years, Stage II-3 eruptions produced Yotei tephra group II-3 from ca. 16.5 cal. ka BP until the present day, at low average eruption rates (0.009 km3 DRE/ky). Whole-rock geochemical compositions vary within each tephra group over the entire eruption history. For example, group I and II-3 tephras contain the lowest and highest abundances, respectively, of K2O, P2O5, and Zr. Group II-1 has the

  4. Active Volcanic Eruptions on Io

    NASA Technical Reports Server (NTRS)

    1996-01-01

    Six views of the volcanic plume named Prometheus, as seen against Io's disk and near the bright limb (edge) of the satellite by the SSI camera on the Galileo spacecraft during its second (G2) orbit of Jupiter. North is to the top of each frame. To the south-southeast of Prometheus is another bright spot that appears to be an active plume erupting from a feature named Culann Patera. Prometheus was active 17 years ago during both Voyager flybys, but no activity was detected by Voyager at Culann. Both of these plumes were seen to glow in the dark in an eclipse image acquired by the imaging camera during Galileo's first (G1) orbit, and hot spots at these locations were detected by Galileo's Near-Infrared Mapping Spectrometer.

    The plumes are thought to be driven by heating sulfur dioxide in Io's subsurface into an expanding fluid or 'geyser'. The long-lived nature of these eruptions requires that a substantial supply of sulfur dioxide must be available in Io's subsurface, similar to groundwater. Sulfur dioxide gas condenses into small particles of 'snow' in the expanding plume, and the small particles scatter light and appear bright at short wavelengths. The images shown here were acquired through the shortest-wavelength filter (violet) of the Galileo camera. Prometheus is about 300 km wide and 75 km high and Culann is about 150 km wide and less than 50 km high. The images were acquired on September 4, 1996 at a range of 2,000,000 km (20 km/pixel resolution). Prometheus is named after the Greek fire god and Culann is named after the Celtic smith god.

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the

  5. Seeking a paleontological signature for mass extinctions caused by flood basalt eruptions

    NASA Astrophysics Data System (ADS)

    Payne, J.; Bush, A. M.; Chang, E. T.; Heim, N. A.; Knope, M. L.; Pruss, S. B.

    2016-12-01

    Flood basalt eruptions coincide with numerous extinction events in the fossil record. Increasingly precise absolute age determinations for both the timing of eruption and of species extinctions have strengthened the case for flood basalt eruptions as the single most important trigger for major mass extinction events in the fossil record. However, the extent to which flood basalt eruptions cause a pattern of biotic loss distinctive from extinctions triggered by other geological or biological processes remains an open question. In the absence of diagnostic mapping between geological triggers and biological losses, establishing the identities of causal agents for mass extinctions will continue to depend primarily on evidence for temporal coincidence. Here we use a synoptic database of marine animal genera spanning the Phanerozoic, including times of first and last occurrence, body size, motility, life position, feeding mode, and respiratory physiology to assess whether extinction events temporally associated with flood basalt eruptions exhibit a diagnostic pattern of extinction selectivity. We further ask whether any events not associated with known large igneous provinces nevertheless display extinction patterns suggestive of such a cause. Finally, we ask whether extinction events associated with other primary causes, such as glaciation or bolide impact, are distinguishable from events apparently triggered by flood basalt eruptions on the basis of extinction selectivity patterns

  6. Solar Eruptions: Coronal Mass Ejections and Flares

    NASA Technical Reports Server (NTRS)

    Gopalswamy, Nat

    2012-01-01

    This lecture introduces the topic of Coronal mass ejections (CMEs) and solar flares, collectively known as solar eruptions. During solar eruptions, the released energy flows out from the Sun in the form of magnetized plasma and electromagnetic radiation. The electromagnetic radiation suddenly increases the ionization content of the ionosphere, thus impacting communication and navigation systems. Flares can be eruptive or confined. Eruptive flares accompany CMEs, while confined flares hav only electromagnetic signature. CMEs can drive MHD shocks that accelerate charged particles to very high energies in the interplanetary space, which pose radiation hazard to astronauts and space systems. CMEs heading in the direction of Earth arrive in about two days and impact Earth's magnetosphere, producing geomagnetic storms. The magnetic storms result in a number of effects including induced currnts that can disrupt power grids, railroads, and underground pipelines

  7. Depth of origin of magma in eruptions.

    PubMed

    Becerril, Laura; Galindo, Ines; Gudmundsson, Agust; Morales, Jose Maria

    2013-09-26

    Many volcanic hazard factors--such as the likelihood and duration of an eruption, the eruption style, and the probability of its triggering large landslides or caldera collapses--relate to the depth of the magma source. Yet, the magma source depths are commonly poorly known, even in frequently erupting volcanoes such as Hekla in Iceland and Etna in Italy. Here we show how the length-thickness ratios of feeder dykes can be used to estimate the depth to the source magma chamber. Using this method, accurately measured volcanic fissures/feeder-dykes in El Hierro (Canary Islands) indicate a source depth of 11-15 km, which coincides with the main cloud of earthquake foci surrounding the magma chamber associated with the 2011-2012 eruption of El Hierro. The method can be used on widely available GPS and InSAR data to calculate the depths to the source magma chambers of active volcanoes worldwide.

  8. The 1991 eruptions of Mount Pinatubo, Philippines

    USGS Publications Warehouse

    Wolfe, Edward W.

    1992-01-01

    Recognition of the volcanic unrest at Mount Pinatubo in the Philippines began when steam explosions occurred on April 2, 1991. The unrest culminated ten weeks later in the world's largest eruption in more than half a century. 

  9. NASA Spacecraft Images Mexican Volcanic Eruption

    NASA Image and Video Library

    2012-04-24

    NASA Terra spacecraft shows Mexico active Popocatepetl volcano, located about 40 miles southeast of Mexico City, spewing water vapor, gas, ashes and glowing rocks since its most recent eruption period began in April 2012.

  10. NASA Spacecraft Eyes Iceland Volcanic Eruption

    NASA Image and Video Library

    2014-09-03

    On the night of Sept. 1, 2014, NASA Earth Observing 1 EO-1 spacecraft observed the ongoing eruption at Holuhraun, Iceland. This false-color image that emphasizes the hottest areas of the vent and resulting lava flows.

  11. Seasonal variations of volcanic eruption frequencies

    NASA Technical Reports Server (NTRS)

    Stothers, Richard B.

    1989-01-01

    Do volcanic eruptions have a tendency to occur more frequently in the months of May and June? Some past evidence suggests that they do. The present study, based on the new eruption catalog of Simkin et al.(1981), investigates the monthly statistics of the largest eruptions, grouped according to explosive magnitude, geographical latitude, and year. At the 2-delta level, no month-to-month variations in eruption frequency are found to be statistically significant. Examination of previously published month-to-month variations suggests that they, too, are not statistically significant. It is concluded that volcanism, at least averaged over large portions of the globe, is probably not periodic on a seasonal or annual time scale.

  12. Analyses of Etna Eruptive Activity From 18th Century and Characterization of Flank Eruptions

    NASA Astrophysics Data System (ADS)

    del Carlo, P.; Branca, S.; Coltelli, M.

    2003-12-01

    Etna explosive activity has usually been considered subordinate with respect to the effusive eruptions. Nevertheless, in the last decade and overall after the 2001 and 2002 flank eruptions, explosive activity has drawn the attention of the scientific and politic communities owing to the damages that the long-lasting ash fall caused to Sicily's economy. We analyzed the eruptions from the 18th century to find some analogous behavior of Etna in the past. A study of the Etna historical record (Branca and Del Carlo, 2003) evidenced that after the 1727 eruption, there are no more errors in the attribution of the year of the eruption. Furthermore from this time on, the scientific quality of the chronicles allowed us to obtain volcanological information and to estimate the magnitude of the major explosive events. The main goal of this work was to characterize the different typologies of Etna eruptions in the last three centuries. Meanwhile, we have tried to find the possible relationship between the two kinds of activity (explosive and effusive) in order to understand the complexity of the eruptive phenomena and define the short-term behavior of Etna. On the base of the predominance of the eruptive typology (effusive or explosive) we have classified the flank eruptions in three classes: i) Type 1: almost purely effusive; ii) Type 2: the intensity of explosive activity comparable with the effusive; iii) Type 3: almost purely explosive with minor lava effusion (only the 1763 La Montagnola and 2002 eruptions belong to this class). Long-lasting explosive activity is produced by flank eruptions with continuous ash emission and prolonged fallout on the flanks (e.g. 1763, 1811, 1852-53, 1886, 1892, 2001 and 2002 eruptions). At summit craters continuous activity is weaker, whereas the strongest explosive eruptions are short-lived events. Furthermore, from the 18th to 20th century there were several years of intense and discontinuous summit explosive activity, from high strombolian

  13. Eruptive history of the Dieng Mountains region, central Java, and potential hazards from future eruptions

    USGS Publications Warehouse

    Miller, C. Dan; Sushyar, R.; ,; Hamidi, S.

    1983-01-01

    The Dieng Mountains region consists of a complex of late Quaternary to recent volcanic stratocones, parasitic vents, and explosion craters. Six age groups of volcanic centers, eruptive products, and explosion craters are recognized in the region based on their morphology, degree of dissection, stratigraphic relationships, and degree of weathering. These features range in age from tens of thousands of years to events that have occurred this century. No magmatic eruptions have occurred in the Dieng Mountains region for at least several thousand years; volcanic activity during this time interval has consisted of phreatic eruptions and non-explosive hydrothermal activity. If future volcanic events are similar to those of the last few thousand years, they will consist of phreatic eruptions, associated small hot mudflows, emission of suffocating gases, and hydrothermal activity. Future phreatic eruptions may follow, or accompany, periods of increased earthquake activity; the epicenters for the seismicity may suggest where eruptive activity will occur. Under such circumstances, the populace within several kilometers of a potential eruption site should be warned of a possible eruption, given instructions about what to do in the event of an eruption, or temporarily evacuated to a safer location.

  14. It is not a fixed drug eruption, it is a fixed "sunlight" eruption.

    PubMed

    Valdivieso, Rommel; Cañarte, Cecilia

    2010-12-01

    Hyperpigmented fixed eruption is a phenomenon usually related with drug antigens, and known as fixed drug eruption. A woman had a skin condition with clinical and histopathologic indications of fixed drug eruption. The disease first appeared when she went to a swimming pool and left with hyperpigmented macules. Previously affected skin reactivated on three other occasions when she again visited swimming pools. Sunlight involvement (UVA-UVB) was demonstrated through phototests. Sunlight should be considered as a cause of fixed drug-like eruption and a possible cause of some cases of FDE without any apparent etiological factor. © 2010 The International Society of Dermatology.

  15. The 2008 eruption of Chaitén volcano, Southern Chile: a tectonically controlled eruption?

    NASA Astrophysics Data System (ADS)

    Lara, L. E.; Pallister, J. S.; Ewert, J. W.

    2008-12-01

    The May, 2008 - present eruption at Chaitén caldera is the only example of a geophysically monitored rhyolite eruption. Geologic and seismic monitoring was conducted by the Chilean Servicio Nacional de Geología y Minería (SERNAGEOMIN) with assistance from the Volcano Disaster Assistance Program (VDAP, a joint program of USGS and OFDA). In addition, global remote sensing assets were focused on the eruption and provide extensive data on the eruptive plume and ash cloud. An initial analysis of seismic and observational monitoring and remote sensing data lead us to suggest that the Chaitén eruption was tectonically controlled, as described below. The Chaitén eruption began abruptly with Plinian ash columns (May 2-8), and then transitioned into lava dome effusion accompanied by continuous low-level ash plumes. Heights and durations of the Plinian phase of the eruption initially suggested magmatic volumes of up to as much as 1 km3, ranking this as a large VEI 4 or possibly a small VEI 5 eruption. However, reports of relatively modest thicknesses of downwind tephra indicate a smaller explosivity, probably in the moderate VEI 4 range. Extrusion of the lava dome continues at a high rate as of this time (mid-September, 2008). We estimate a lava volume of >0.3 km3 and eruption rates that have frequently exceeded 20 m3s-1, anomalously high rates for a sustained lava dome eruption. Little detailed on-site study of the proximal deposits of the eruption has been possible because of continued hazards from the eruption and austral winter weather conditions. However, several inferences about the nature of the eruption are evident. The apparent lack of historic eruptions, absence of a hydrothermal system, rapid onset of the eruption, crystal-poor rhyolite composition, lack of decompression reaction rims on amphibole crystals, and relatively high magmatic temperatures (about 860°C, as reported elsewhere in this session) all argue for rapid ascent of magma from depth. The

  16. Late Holocene Andesitic Eruptions at Mount Rainier

    NASA Astrophysics Data System (ADS)

    Sisson, T. W.; Vallance, J. W.

    2005-12-01

    Holocene Mt. Rainier erupted much more frequently than is recorded by its 11 pumiceous tephras. In the 2.6-2.2 ka Summerland eruptive period, 6 groups of thin (1-5 mm) Sparsely Vesicular Glassy (SVG) ashes were deposited (S1-S6), followed by the 0.3 km3 C-tephra. Two groups of andesitic lava flows and one andesitic block-and-ash flow (2.45 ka) also erupted in the Summerland period (ice conceals any other products). Based on glass composition the pyroclastic flow correlates with S4 ashes that also contain pumiceous grains and rare pumice lapilli. The first of the lava groups, exposed in windows through the Emmons and Winthrop glaciers, is Sr-rich for Mt. Rainier eruptives and correlates with S5 & S6 ashes based on similar high-Sr plagioclase. The ensuing C-tephra formed by plinian eruption of mixed and mingled magma comprising 4 juvenile components: mixed porphyritic andesite pumice, crystal-poor andesite scoria, vesicular high-Sr dacite blebs in pumice and scoria, and poorly inflated crystal-rich high-Sr dacite. High-Sr components were probably entrained conduit linings and segregations from the preceding high-Sr eruptions. The youngest lava group, exposed at the summit, is normal-Sr andesite lacking mixing textures of the C-tephra, and represents eruption of another small batch of andesitic magma perhaps just after the C event. SVG ash grains have blocky-to-fluidal shapes, are rich in plagioclase microlites, and their glasses are high-SiO2 (66-78%) and low-Al2O3 (15-11%). Melting experiments yield apparent equilibration pressures <50MPa for SVG liquids. SVG ashes likely result from shallow hydromagmatic explosions as largely degassed magmas transited the upper-edifice hydrothermal system during effusive eruptions. Rare pumice lapilli codeposited with S1, S2, and S4 ashes have microlite-free dacitic glasses, one with nonreacted hbl phenocrysts. These pumice formed from magmas that ascended rapidly from reservoir depths, synchronous with or closely between effusive

  17. The dynamics of explosive volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Woods, Andrew W.

    1995-11-01

    Explosive volcanic eruptions involve the ejection of dense mixtures of ash and gas from a volcanic vent at high speed and pressure. This mixture is generated as liquid magma rises from a crustal magma chamber and decompresses, exsolving water vapor. As gas is exsolved, the mixture inflates, accelerates, and becomes foam-like. Once the liquid films around the bubbles are unable to spread as rapidly as the bubbles are expanding through decompression, the films rupture, and a fragmented mixture of ash and volatiles ascends to the volcanic vent. On eruption from the vent, the material decompresses, either into a volcanic crater or directly into the atmosphere. In the case of free decompression, the mixture typically has a high speed, while decompression in a crater can lead to either very low or very high eruption speeds. After decompression, the hot, dense mixture begins to entrain and heat ambient air, thereby lowering the mixture density, but it also decelerates under gravity. If the eruption velocity is sufficiently high, then the material can become buoyant and will generate a buoyant ash plume, called a Plinian eruption column, which rises above the vent. In contrast, if the eruption velocity is small or the mass flux is very large, then the material will typically collapse back toward the Earth and form a dense, laterally spreading flow. Buoyant eruption columns are able to transport the material high into the atmosphere, since they provide an efficient means of converting the initial thermal energy of the mixture into potential energy through entrainment and heating of ambient air. The height of rise of such eruption columns depends upon the eruption rate, the stratification of the atmosphere, the degree of thermal disequilibrium between the particles and the air, and the amount of water vapor in the atmosphere. Dense, hot ash flows, generated by collapsing fountains, transport ash and clasts laterally from the vent, sedimenting many of the larger clasts and

  18. Preventive health measures in volcanic eruptions.

    PubMed Central

    Baxter, P J; Bernstein, R S; Buist, A S

    1986-01-01

    Medical treatment has only a small role in severe volcanic eruptions and so preventive measures are paramount if injuries and loss of life are to be reduced. The health team must be incorporated in emergency planning and response at the earliest stage. Guidance on the interpretation of geological information about a volcano and the appropriate health measures that should be adopted before and after an eruption are summarized for the benefit of health workers. PMID:3946731

  19. Mt. Pinatubo Volcano - Post Eruption, Luzon, Philippines

    NASA Image and Video Library

    1992-08-08

    Mt. Pinatubo on the island of Luzon (15.0N, 120.0E) erupted catastrophically in June 1991 after over 600 years of inactivity. In this vertical view, the full extent of the eruption is obvious. Thick layers of ash completely surrounds the crater and the effect of mudflows in this previously heavily forested and agricultural region can be traced as ribbons flowing downhill. Clark AFB, once the crossroads of the SW Pacific can only partially be seen.

  20. Volcanic eruptions; energy and size

    USGS Publications Warehouse

    de la Cruz-Reyna, S.

    1991-01-01

    The Earth is a dynamic planet. Many different processes are continuously developing, creating a delicate balance between the energy stored and generated in its interior and the heat lost into space. The heat in continuously transferred through complex self-regulating convection mechanisms on a planetary scale. The distribution of terrestrial heat flow reveals some of the fine structure of the energy transport mechanisms in the outer layers of the Earth. Of these mechanisms in the outer layers of the Earth. Of these mechanisms, volcanism is indeed the most remarkable, for it allows energy to be transported in rapid bursts to the surface. In order to maintain the subtle balance of the terrestrial heat machine, one may expect that some law or principle restricts the ways in which these volcanic bursts affect the overall energy transfer of the Earth. For instance, we know that the geothermal flux of the planet amounts to 1028 erg/year. On the other hand, a single large event like the Lava Creek Tuff eruption that formed Yellowstone caldera over half a million years ago may release the same amount of energy in a very small area, over a short period of time. 

  1. Eruptive Trio Seen by STEREO

    NASA Image and Video Library

    2017-12-08

    NASA image acquired May 1, 2010. As an active region rotated into view, it blew out three relatively small eruptions over about two days (Apr. 30 - May 2) as STEREO (Ahead) observed in extreme UV light. The first one was the largest and exhibited a pronounced twisting motion (shown in the still from May 1, 2010). The plasma, not far above the Sun's surface in these images, is ionized Helium heated to about 60,000 degrees. Note, too, the movement of plasma flowing along magnetic field lines that extend out beyond and loop back into the Sun's surface. Such activity occurs every day and is part of the dynamism of the changing Sun. Credit: NASA/GSFC/STEREO To learn more about STEREO go to: soho.nascom.nasa.gov/home.html NASA Goddard Space Flight Center is home to the nation's largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

  2. Eruption reported in Aleutian Islands

    NASA Astrophysics Data System (ADS)

    On November 29, an airplane pilot reported the start of an eruption on Mount Westdahl on Unimak Island in the Aleutian Islands (54.52°N, 164.65°W), according to the Smithsonian Institution's Global Volcanism Network. The pilot sighted an ash plume rising to more than 7 km altitude at 1705 local time ( = UT-11 hours). The main portion of the plume, at about 5 km altitude, extended 80-95 km east-northeast by 0930 the next morning.About noon, U.S. Coast Guard pilots observed a NE-SW fissure vent 5-8 km long, with at least one active lava flow traveling down the east flank. The area surrounding the vent was ash-covered, and increased runoff and possible mudflows were observed. Vigorous steam and ash emission was visible throughout the day from False Pass (90 km NE), which experienced a very fine dusting of ash. A strong sulfur odor at False Pass lasted into the night, and similar odors were reported by pilots up to several hundred kilometers inland. No ashfall has been reported in Cold Bay (145 km NE).

  3. Recent eruptions at Bezymianny volcano-A seismological comparison

    NASA Astrophysics Data System (ADS)

    West, Michael E.

    2013-08-01

    For the past few decades, Bezymianny volcano has erupted once to twice per year. Here, I examine eight eruptive events between 2006 and 2010. This is the first time period for which proximal or broadband seismic data have been recorded at Bezymianny. Several recurring patterns are demonstrated in advance of eruptions. Eruptions are generally preceded by 12-36 h of tremor energy elevated by 2 to 3 orders of magnitude. Locatable earthquake activity is quite erratic in the days before eruptions. For eruptions of juvenile magma, however, the cumulative moment magnitude increases with the repose time since the previous eruption. Though tenuous, this relationship is statistically significant and could improve forecasts of Bezymianny eruptions. The most energetic eruptions demonstrate increasing multiplet activity in the run-up, followed by a rapid cessation at the time of eruption. When present, this behavior marks increasing pressure in the conduit system as degassing eclipses the capacity for venting. Very long period seismicity (> 20 s periods) accompanies some eruptions. These tend to be the same short-lived high-energy eruptions that exhibit multiplet precursors. Four eruptions are examined in detail to illustrate the variety in eruption mechanisms. Lava dome collapses, sustained eruptions, singular paroxysmal explosions and post-explosion lava flows occur in different combinations demonstrating that more than one eruption trigger is regulating Bezymianny. Compared to Bezymianny's fifty-year modern history, recent eruptions have been shorter-lived and separated by longer repose times. Some evidence suggests that these eruptions may be increasingly explosive-a speculation that carries significant hazard implications. If true, however, this threat is tempered by solid evidence that the most explosive eruptions are preceded by the clearest precursors, suggesting an ability to improve the already excellent eruption forecasts available for Bezymianny.

  4. The ten-year eruption of Kilauea Volcano

    USGS Publications Warehouse

    Clague, D.A.; Heliker, C.

    1992-01-01

    About 1 km3 of lava erupted during the first 0 years of the eruption. Lava flows have destroyed 181 houses and severed the coastal highway along the volcano's south flank, severely restricting transportation on this part of the island of Hawaii. the eruption consisted of many distinct episodes characterized by activity at different vents and by different eruptive styles. the following summarizes the first 10 years of the eruption, starting with the initial outbreak in 1983.

  5. Reduced cooling following future volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Hopcroft, Peter O.; Kandlbauer, Jessy; Valdes, Paul J.; Sparks, R. Stephen J.

    2017-11-01

    Volcanic eruptions are an important influence on decadal to centennial climate variability. Large eruptions lead to the formation of a stratospheric sulphate aerosol layer which can cause short-term global cooling. This response is modulated by feedback processes in the earth system, but the influence from future warming has not been assessed before. Using earth system model simulations we find that the eruption-induced cooling is significantly weaker in the future state. This is predominantly due to an increase in planetary albedo caused by increased tropospheric aerosol loading with a contribution from associated changes in cloud properties. The increased albedo of the troposphere reduces the effective volcanic aerosol radiative forcing. Reduced sea-ice coverage and hence feedbacks also contribute over high-latitudes, and an enhanced winter warming signal emerges in the future eruption ensemble. These findings show that the eruption response is a complex function of the environmental conditions, which has implications for the role of eruptions in climate variability in the future and potentially in the past.

  6. Identifying recycled ash in basaltic eruptions.

    PubMed

    D'Oriano, Claudia; Bertagnini, Antonella; Cioni, Raffaello; Pompilio, Massimo

    2014-07-28

    Deposits of mid-intensity basaltic explosive eruptions are characterized by the coexistence of different types of juvenile clasts, which show a large variability of external properties and texture, reflecting alternatively the effects of primary processes related to magma storage or ascent, or of syn-eruptive modifications occurred during or immediately after their ejection. If fragments fall back within the crater area before being re-ejected during the ensuing activity, they are subject to thermally- and chemically-induced alterations. These 'recycled' clasts can be considered as cognate lithic for the eruption/explosion they derive. Their exact identification has consequences for a correct interpretation of eruption dynamics, with important implications for hazard assessment. On ash erupted during selected basaltic eruptions (at Stromboli, Etna, Vesuvius, Gaua-Vanuatu), we have identified a set of characteristics that can be associated with the occurrence of intra-crater recycling processes, based also on the comparison with results of reheating experiments performed on primary juvenile material, at variable temperature and under different redox conditions.

  7. Identifying recycled ash in basaltic eruptions

    PubMed Central

    D'Oriano, Claudia; Bertagnini, Antonella; Cioni, Raffaello; Pompilio, Massimo

    2014-01-01

    Deposits of mid-intensity basaltic explosive eruptions are characterized by the coexistence of different types of juvenile clasts, which show a large variability of external properties and texture, reflecting alternatively the effects of primary processes related to magma storage or ascent, or of syn-eruptive modifications occurred during or immediately after their ejection. If fragments fall back within the crater area before being re-ejected during the ensuing activity, they are subject to thermally- and chemically-induced alterations. These ‘recycled' clasts can be considered as cognate lithic for the eruption/explosion they derive. Their exact identification has consequences for a correct interpretation of eruption dynamics, with important implications for hazard assessment. On ash erupted during selected basaltic eruptions (at Stromboli, Etna, Vesuvius, Gaua-Vanuatu), we have identified a set of characteristics that can be associated with the occurrence of intra-crater recycling processes, based also on the comparison with results of reheating experiments performed on primary juvenile material, at variable temperature and under different redox conditions. PMID:25069064

  8. Expanding the spectrum of PTH1R mutations in patients with primary failure of tooth eruption.

    PubMed

    Roth, Helmut; Fritsche, Lars G; Meier, Christoph; Pilz, Peter; Eigenthaler, Martin; Meyer-Marcotty, Philipp; Stellzig-Eisenhauer, Angelika; Proff, Peter; Kanno, Cláudia M; Weber, Bernhard Hf

    2014-01-01

    Primary failure of tooth eruption (PFE) is a rare autosomal-dominant disease characterized by severe lateral open bite as a consequence of incomplete eruption of posterior teeth. Heterozygous mutations in the parathyroid hormone 1 receptor (PTH1R) gene have been shown to cause PFE likely due to protein haploinsufficiency. To further expand on the mutational spectrum of PFE-associated mutations, we report here on the sequencing results of the PTH1R gene in 70 index PFE cases. Sanger sequencing of the PTH1R coding exons and their immediate flanking intronic sequences was performed with DNA samples from 70 index PFE cases. We identified a total of 30 unique variants, of which 12 were classified as pathogenic based on their deleterious consequences on PTH1R protein while 16 changes were characterized as unclassified variants with as yet unknown effects on disease pathology. The remaining two variants represent common polymorphisms. Our data significantly increase the number of presently known unique PFE-causing PTH1R mutations and provide a series of variants with unclear pathogenicity which will require further in vitro assaying to determine their effects on protein structure and function. Management of PTH1R-associated PFE is problematic, in particular when teeth are exposed to orthodontic force. Therefore, upon clinical suspicion of PFE, molecular DNA testing is indicated to support decision making for further treatment options.

  9. Fracture susceptibility of worn teeth.

    PubMed

    Keown, Amanda J; Bush, Mark B; Ford, Chris; Lee, James J-W; Constantino, Paul J; Lawn, Brian R

    2012-01-01

    An experimental simulation study is made to determine the effects of occlusal wear on the capacity of teeth to resist fracture. Tests are carried out on model dome structures, using glass shells to represent enamel and epoxy filler to represent dentin. The top of the domes are ground and polished to produce flat surfaces of prescribed depths relative to shell thickness. The worn surfaces are then loaded axially with a hard sphere, or a hard or soft flat indenter, to represent extremes of food contacts. The loads required to drive longitudinal cracks around the side walls of the enamel to failure are measured as a function of relative wear depth. It is shown that increased wear can inhibit or enhance load-bearing capacity, depending on the nature of the contact. The results are discussed in the context of biological evolutionary pressures. Copyright © 2011 Elsevier Ltd. All rights reserved.

  10. Preparing for the next eruption in the Cascades: Unexpected outcomes from the 2004 - 2008 eruption of Mount St. Helens, Washington (Invited)

    NASA Astrophysics Data System (ADS)

    Schilling, S. P.

    2010-12-01

    , there were no large lahars during the eruption because no process caused rapid glacial melting. Nevertheless, the baseline data sets and established techniques proved valuable to track the eruption. Between 2004 and 2008, Mount St. Helens extruded about 9 x 107 m3 of lava onto the crater floor immediately south of the 1980-1986 lava dome. As the eruption proceeded we used techniques of photogrammetry developed prior to the eruption to construct a series of DEMs from aerial photographs to measure changes in volume and position associated with dome growth as well as to calculate rates of ground deformation and melting of glacial ice. The volumetric growth rate of the dome ranged from about 9 m3/sec very early in the eruption to 1-3 m3/sec during most of the eruption. The volume of the surviving glacier is about 6 x 107 m3 , about 85% of the volume prior to the eruption.

  11. Transplantation of Cryopreserved Teeth: A Systematic Review

    PubMed Central

    Osathanon, Thanaphum

    2010-01-01

    The aim of this article was to examine the research articles regarding biological and mechanical properties of cryopreserved teeth for potential use in tooth transplantation. A systematic review of literatures was performed by Pubmed searching with assigned key words from January 1, 1990 to June 8, 2009. All articles were examined for inclusion criteria. Secondary search was conducted by hand-search through references of included articles from primary search. A total of 24 articles were obtained from both primary and secondary search and used as fundamental articles in this review. Periodontal ligament tissues of cryopreserved teeth were able to maintain their biological properties resulted in a satisfactory healing of periodontium. Dental pulp tissues, however, may be compromised by limitation of permeability of cryopreservative agent into pulp cavity. Therefore, an endodontic treatment of transplanted cryopreserved teeth was recommended. Cryopreserved teeth had comparable mechanical properties to those of normal teeth. Importantly, the success of cryopreserved tooth transplantation treatment in orthodontic patients was reported. The cryopreserved teeth for tooth banking have a potential clinical application for treatment of missing teeth. Case selection, however, is critical for treatment success. More studies and data regarding masticatory function and periodontal healing of transplanted cryopreserved teeth are needed. PMID:20737931

  12. Disinfection of Human Teeth for Educational Purposes.

    ERIC Educational Resources Information Center

    Tate, William H.; White, Robert S.

    1991-01-01

    A study investigated the efficacy of glutaraldehyde and several other disinfectants for disinfecting teeth to be used for teaching and research, as an alternative to autoclaving for teeth with amalgam restorations. Results indicate that formalin was the only disinfectant that penetrated tooth pulp chambers in effective antimicrobial…

  13. Coronal tissue loss in endodontically treated teeth.

    PubMed

    Sulaiman, A O; Shaba, O P; Dosumu, O O; Ajayi, D M

    2012-12-01

    To categorize the endodontically treated teeth according to the extent of coronal tissue loss in order to determine the appropriate restoration required. A two year descriptive study was done at the Conservative Clinic of the Department of Restorative Dentistry, Dental Centre, University College Hospital, Ibadan. Successful endodontically treated teeth were assessed and categorized according to the extent of tissue loss based on standard criteria proposed by Smith and Schuman. Two hundred and ninety endodontically treated teeth were assessed for success both clinically and radiographically. Eighty (27.6%) were anterior teeth, 78 (26.9%) were premolars while 132 (45.5%) were molars. Dental caries was found to be the most common (61.4%) indication for endodontic treatment and caused more coronal tissue damage (moderate and significant) when compared with other indications for endodontic treatment. Two hundred and twenty seven (78.3%) endodontically treated teeth had moderate coronal tissue loss, 41 (14.1%) had minimal damage while 22 (7.6%) had significant tissue damage. Dental caries was the most common indication for endodontic treatment of the posterior teeth while trauma was the most common indication for the anterior teeth. Majority of the endodontically treated teeth that were evaluated for tissue loss had moderate coronal tissue damage. It is therefore recommended that proper and prompt evaluation of the remaining coronal tooth tissue following successful endodontic treatment be carried out in order to determine the appropriate definitive restoration required that will be easy for the clinician and less expensive to the patients.

  14. Extracted teeth: decontamination, disposal and use.

    PubMed

    Cuny, E; Carpenter, W M

    1997-11-01

    With the advent of medical waste and OSHA infection control regulations, many practitioners are unsure about the legal, proper handling of extracted teeth. This article outlines the options available for the disposal of extracted teeth and explains the role each regulatory agency plays in the process.

  15. Associations between the number of natural teeth in postmenopausal women and hormone replacement therapy.

    PubMed

    Han, Kyungdo; Ko, Youngkyung; Park, Yong-Gyu; Park, Jun-Beom

    2016-12-01

    Increasing research suggests that periodontal status is associated with hormone replacement therapy in postmenopausal women. This study was performed to assess the relationship between the number of natural teeth and ever use of hormone replacement therapy in postmenopausal women using nationally representative Korean data. Data from the Korea National Health and Nutrition Examination Survey between 2010 and 2012 were used, and the analysis in this study was confined to a total of 4869 respondents over 19 years old who had gone through menopause and who had no missing data for the reproductive factors and outcome variables in that study. The total number of natural teeth was then calculated after excluding third molars. The time of day when tooth brushing was done was recorded as representative oral health behavior. Multiple logistic regression analyses were used to assess association between the number of natural teeth and the use of hormone replacement therapy. Among participants who had ever used hormone replacement therapy, the proportions (percentage and standard error) with no teeth, 1-9 teeth, 10-19 teeth, 20-27 teeth, and 28 teeth were 5.0±2.4%, 6.7±1.4%, 12.5±1.7%, 18.9±1.0%, and 20.7±1.6%, respectively (P<0.05). The adjusted odds ratio and 95% confidence interval for having fewer than 20 teeth <20 was 0.624 [0.464-0.840] for the individuals using hormone replacement therapy, after adjustments. The analysis revealed that the use of hormone replacement therapy by postmenopausal women showed positive effects for retention of natural teeth. Lack of hormone replacement therapy may be considered to be an independent risk indicator for tooth loss in Korean postmenopausal women. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  16. A set of hypotheses on tribology of mammalian herbivore teeth

    NASA Astrophysics Data System (ADS)

    Kaiser, Thomas M.; Clauss, Marcus; Schulz-Kornas, Ellen

    2016-03-01

    Once erupted, mammal cheek teeth molars are continuously worn. Contact of molar surfaces with ingesta and with other teeth contribute to this wear. Microscopic wear features (dental surface texture) change continuously as new wear overprints old texture features. These features have been debated to indicate diet. The general assumption in relating occlusal textures to diet is that they are independent of masticatory movements and forces. If this assumption is not accepted, one needs to propose that occlusal textures comprise signals not only from the ‘last supper’ but also from masticatory events that represent ecological, species- or taxon-specific adaptations, and that occlusal textures therefore give a rather unspecific, somehow diet-related signal that is functionally inadequately understood. In order to test for mechanical mechanisms of wear, we created a hypothesis matrix that related sampled individuals with six tribological variables. Three variables represent mechanically relevant ingesta properties, and three represent animal-specific characteristics of the masticatory system. Three groups of mammal species (free ranging Cetartiodactyla and Perissodactyla, free ranging primates, and artificially fed rabbits) were investigated in terms of their 3D dental surface textures, which were quantified employing ten ISO 25178 surface texture parameters. We first formulated a set of specific predictions based on theoretical reflections on the effects of diet properties and animal characteristics, and subsequently performed discriminant analysis to test which parameters actually followed these predictions. We found that parameters Vvc, Vmc, Sp, Sq allowed the prediction of both, ingesta properties and properties of the masticatory system, if combined with other parameters. Sha, Sda and S5v had little predictive power in our dataset. Spd seemed rather unrelated to ingesta properties and made this parameter a suitable indicator of masticatory system properties.

  17. Volatile Release and Eruption Dynamics of a Basaltic Plinian Eruption From Masaya Caldera, Nicaragua

    NASA Astrophysics Data System (ADS)

    Wehrmann, H.; Freundt, A.; Kutterolf, S.; Schmincke, H.; Strauch, W.

    2003-12-01

    Our project is part of SFB 574 "Volatiles and Fluids in subduction zones", and focusses on degassing dynamics of highly-explosive arc volcanoes. Masaya Caldera in west-central Nicaragua is part of the Central American volcanic arc at the convergent boundary of the Cocos and Carribean plates. A basaltic plinian eruption of VEI 6 occurred at Masaya Caldera in the Late-Pleistocene, depositing a widespread fan of scoria lapilli, named Fontana Tephra. We have constrained parameters of the Fontana eruption by extensive isopach and isopleth mapping. Total erupted tephra volume is >0.83 km3 (about 1012 kg DRE). The eruption columns reached 30 to 35 km height at an average discharge rate of 1.3*108 kg/s. This violent eruption was not continuous but proceeded in distinct pulses evident by the well-bedded deposit. An initial sequence of numerous highly explosive but short pulses formed a well-bedded layer of very highly vesicular, hawaiian-type lapilli, possibly representing a gas-enriched top zone of the magma reservoir. The following series of longer-duration plinian events, interupted by weak phases of ash emission, formed beds of highly vesicular scoria lapilli. The eruption ceased with abundant short-lived pulses of lower-energy subplinian activity. We estimate volatile emissions during the eruption from the differences in volatile concentration between matrix glass and glass inclusions in minerals, considered to represent degassed and undegassed melt, respectively. Concentrations of fluorine of about 7000 ppm are about equal in matrix glass and glass inclusions, indicating little degassing of fluorine during eruption. Chlorine contents amount to 1200 ppm in the inclusions, and to about 1000 ppm in matrix glass. The concentration difference, multiplied by erupted magma mass, suggests a total chlorine emission of 16 Mt. Apparently only little chlorine exsolved in the initial eruption phase, but degassing strongly increased during the plinian phase. Sulphur concentrations

  18. Gas-driven eruptions at Mount Ruapehu, New Zealand: towards a coherent model of eruption

    NASA Astrophysics Data System (ADS)

    Kilgour, G. N.; Mader, H. M.; Mangan, M.; Blundy, J.

    2010-12-01

    Mt. Ruapehu is an andesitic cone volcano situated at the southern end of the Taupo Volcanic Zone. The summit plateau at Ruapehu consists of three craters (South, Central and North). Historical activity has consisted of frequent small phreatic and phreatomagmatic eruptions from South Crater. The active vents of South Crater are submerged beneath Crater Lake - a warm, acidic lake. The most recent eruption at Ruapehu occurred on 25th September, 2007 that generated a moderate steam column to about 4.5 km above Crater Lake, and a directed ballistic and surge deposit of coarse blocks and ash to the north of Crater Lake. It also initiated lahars in two catchments. The eruption occurred during the ski season and it resulted in the temporary closure of the three ski fields. Seismicity for the main eruption lasted for about 4 minutes and included an explosive phase which lasted for less than 1 minute and a post-explosion phase which probably indicated resonance in the conduit together with signals generated from lahars and vent stabilisation. Preceding seismicity occurred ~ 10 min before the eruption. The 2007 eruption appears strikingly similar to phreatic/phreatomagmatic eruptions of 1969 and 1975. In those eruptions, limited precursory seismicity was recorded, the bulk of the erupted deposits were accidental lithics, including lake sediments and older lavas, and only a small amount of juvenile material was erupted (~ 5%). It is likely that all three eruptions were driven by magmatic gases, either stored and pressurised beneath a hydrothermal seal, or rapidly exsolved during a gas release event. This poster outlines the plan that we will use to model this common type of eruption at Ruapehu. We will analyse the volatile content of phenocryst-hosted melt inclusions to determine the degassing depth of historic eruptions. This will allow us to identify where the magmas have been or are degassing beneath Crater Lake. Analogue modelling of gas and fluid flow through a visco

  19. The 2010 Eruption of Merapi Volcano, Java, Indonesia: Petrological Insights into Magma Dynamics and Eruptive Behaviour

    NASA Astrophysics Data System (ADS)

    Gertisser, R.; Handley, H.; Preece, K.; Reagan, M.; Berlo, K.; Barclay, J.; Herd, R.

    2012-04-01

    The violent eruption of Merapi volcano (Central Java) that started on 26 October 2010 was the volcano's largest since 1872 and the deadliest event since 1930. Before 2010, Merapi's more recent (historical) eruptive activity was repeatedly characterised by periods of slow lava dome extrusion punctuated by gravitational dome failures, generating small-volume pyroclastic density currents (PDCs) with runout distances of typically less than 10 km. The unforeseen, large-magnitude events in 2010 were unusual in many respects: (1) the eruption was short-lived and started with an explosive phase that was not preceded by a lava dome at the surface; (2) between 31 October and 4 November, a lava dome appeared and grew rapidly within the summit crater, exceeding growth rates observed at the peak of the penultimate eruption in 2006 by a factor of ~ 22; (3) during the most vigorous eruptive phase on 5 November, at least one PDC travelled more than 15 km (more than twice the distance of the largest flows in 2006) beyond the summit along the Gendol river valley, causing widespread devastation on Merapi's south flank; (4) in a late phase of the eruption, pumice-rich PDCs were produced, forming a thin veneer on top of the deposits of the largest PDCs from 5 November; (5) ash emissions from sustained eruption columns resulted in ash fall tens of kilometres from the volcano, affecting, amongst other areas, the volcano's western slopes and the city of Yogyakarta ~ 25 km to the south; and (6) the total deposited volume in 2010, based on provisional estimates, may have been ~ 10 times higher than that of other recent eruptions. Here we report and present new geochemical, Sr-Nd-O isotope and U-series data for the volcanic products (lava dome fragments, magmatic inclusions, scoria, pumice and ash) from various stages of the 2010 eruption of Merapi. These data are discussed in the context of other recent to historical, typically less explosive, dome-forming eruptions to elucidate the driving

  20. Pre-, Syn- and Post Eruptive Seismicity of the 2011 Eruption of Nabro Volcano, Eritrea

    NASA Astrophysics Data System (ADS)

    Goitom, Berhe; Hammond, James; Kendall, Michael; Nowacky, Andy; Keir, Derek; Oppenheimer, Clive; Ogubazghi, Ghebrebrhan; Ayele, Atalay; Ibrahim, Said; Jacques, Eric

    2014-05-01

    Nabro volcano, located in south-east Eritrea, East Africa, lies at the eastern margin of the Afar Rift and the Danakil Depression. Its tectonic behaviour is controlled by the divergence of the Arabian, Nubian and Somali plates. Nabro volcano was thought to be seismically quiet until it erupted in June 2011 with limited warning. The volcano erupted on June 12, 2011 around 20:32 UTC, following a series of earthquakes on that day that reached a maximum magnitude of 5.8. It is the first recorded eruption of Nabro volcano and only the second in Eritrea, following the Dubbi eruption in 1861. A lava flow emerged from the caldera and travelled about 20 km from the vent and buried settlements in the area. At the time of this eruption there was no seismic network in Eritrea, and hence the volcano was not monitored. In this study we use ten Ethiopian, one Yemeni and one Djibouti stations to investigate the seismicity of the area before, during and after the eruption. Four Eritrean seismic stations deployed in June 2011, four days after the eruption, are also included in the dataset. Travel time picks supplied by colleagues from Djibouti were also incorporated into the dataset. Our analysis covers roughly three months before and after the eruption and shows that Nabro was seismically quiet before the eruption (nine events), with the exception of one major earthquake (4.8 magnitude) that occurred on March 31, 2011. In contrast, the region shows continued seismic activity after the eruption (92 events). During the eruption seismicity levels are high (123 events), with two days particularly active, June 12 and June 17 with 85 and 28 discrete events, respectively. Maximum magnitudes of 5.8 and 5.9 were recorded on these two days. The two days of increased seismicity are consistent with satellite observations of the eruption which show two distinct phases of the eruption. The period between these two phases was dominated by volcanic tremor. The tremor signal lasted for almost one

  1. Clinicopathology of soft tissue lesions associated with extracted teeth.

    PubMed

    Gbolahan, Olalere; Fatusi, Olawunmi; Owotade, Foluso; Akinwande, Jelili; Adebiyi, Kehinde

    2008-11-01

    The study assessed the prevalence and the clinical and histologic pattern of soft tissue lesions associated with extracted teeth and determined the validity of clinical diagnoses in comparison with histologic diagnosis. Soft tissue from the apices of 100 teeth extracted by the intra-alveolar approach and from the follicle of 50 teeth extracted by the transalveolar approach was examined histologically subsequent to clinical diagnosis. The subjects were seen within a 2-year period at the Oral Surgery unit of a Nigerian teaching hospital. Association between age, gender, and the histopathologic diagnosis was assessed, and the clinical presumptive diagnoses were compared with the histopathologic diagnoses using the epidemiologic parameters of sensitivity, specificity, and positive and negative predictive values. There were 76 (50.7%) males and 74 (49.3%) females, with age range of 17 to 77 years (33 +/- 14 years). Although clinical diagnosis indicated that all the cases were inflammatory in origin, histopathologic diagnosis reported 84% to be of inflammatory origin, 10% to be normal tissue, and 6% to be noninflammatory in nature. The noninflammatory lesions included dentigerous cyst (4%), central giant cell granuloma (1.3%), and ameloblastoma (0.7%). Gender and age were not associated statistically with type and frequency of pathology. Inflammatory conditions showed the highest sensitivity (98%). The study showed that the probability of clinical misdiagnosis of pathologically significant lesions associated with extracted teeth is lowest with inflammation and highest with cysts and neoplasms. Thus, routine histopathologic examination of all recoverable soft tissues associated with extracted teeth would contribute to improve management of cases although the cost and related implications of this need to be investigated further.

  2. Recurrent CME-like Eruptions in Emerging Flux Regions. I. On the Mechanism of Eruptions

    NASA Astrophysics Data System (ADS)

    Syntelis, P.; Archontis, V.; Tsinganos, K.

    2017-11-01

    We report on three-dimensional (3D) magnetohydrodynamic (MHD) simulations of recurrent eruptions in emerging flux regions. We find that reconnection of sheared field lines, along the polarity inversion line of an emerging bipolar region, leads to the formation of a new magnetic structure, which adopts the shape of a magnetic flux rope (FR) during its rising motion. Initially, the FR undergoes a slow-rise phase and, eventually, it experiences a fast-rise phase and ejective eruption toward the outer solar atmosphere. In total, four eruptions occur during the evolution of the system. For the first eruption, our analysis indicates that the torus instability initiates the eruption and that tether-cutting reconnection of the field lines, which envelop the FR, triggers the rapid acceleration of the eruptive field. For the following eruptions, we conjecture that it is the interplay between tether-cutting reconnection and torus instability that causes the onset of the various phases. We show the 3D shape of the erupting fields, focusing more on how magnetic field lines reconnect during the eruptions. We find that when the envelope field lines reconnect mainly with themselves, hot and dense plasma is transferred closer to the core of the erupting FR. The same area appears to be cooler and less dense when the envelope field lines reconnect with neighboring sheared field lines. The plasma density and temperature distribution, together with the rising speeds, energies, and size of the erupting fields, indicate that they may account for small-scale (mini) coronal mass ejections.

  3. Primary failure of eruption and PTH1R: the importance of a genetic diagnosis for orthodontic treatment planning.

    PubMed

    Frazier-Bowers, Sylvia A; Simmons, Darrin; Wright, J Timothy; Proffit, William R; Ackerman, James L

    2010-02-01

    Primary failure of eruption (PFE) is characterized by nonsyndromic eruption failure of permanent teeth in the absence of mechanical obstruction. Recent studies support that this dental phenotype is inherited and that mutations in PTH1R genes explain several familial cases of PFE. The objective of our study was to investigate how genetic analysis can be used with clinical diagnostic information for improved orthodontic management of PFE. We evaluated a family (n = 12) that segregated an autosomal dominant form of PFE with 5 affected and 7 unaffected persons. Nine available family members (5 male, 4 female) were enrolled and subsequently characterized clinically and genetically. In this family, PFE segregated with a novel mutation in the PTH1R gene. A heterozygous c.1353-1 G>A sequence alteration caused a putative splice-site mutation and skipping of exon 15 that segregated with the PFE phenotype in all affected family members. A PTH1R mutation is strongly associated with failure of orthodontically assisted eruption or tooth movement and should therefore alert clinicians to treat PFE and ankylosed teeth with similar caution-ie, avoid orthodontic treatment with a continuous archwire.

  4. Redoubt Volcano: 2009 Eruption Overview

    NASA Astrophysics Data System (ADS)

    Bull, K. F.

    2009-12-01

    Redoubt Volcano is a 3110-m glaciated stratovolcano located 170 km SW of Anchorage, Alaska, on the W side of Cook Inlet. The edifice comprises a <1500-m-thick sequence of mid-Pleistocene to recent, basaltic to dacitic pyroclastic-, block-and-ash- and lava-flow deposits built on Jurassic tonalite. Magma-ice contact features are common. A dissected earlier cone underlies the E flank of Redoubt. Alunite-bearing debris flows to the SE, E and N suggest multiple flank collapses over Redoubt's history. Most recent eruptions occurred in 1966-68, and 1989-90. In March 2009, Redoubt erupted to produce pyroclastic flows, voluminous lahars, and tephra that fell over large portions of south-central Alaska. Regional and local air traffic was significantly disrupted, Anchorage airport was closed for over 12 hours, and oil production in Cook Inlet was halted for nearly five months. Unrest began in August, 2008 with reports of H2S odor. In late September, the Alaska Volcano Observatory (AVO)’s seismic network recorded periods of volcanic tremor. Throughout the fall, AVO noted increased fumarolic emissions and accompanying ice- and snow-melt on and around the 1990 dome, and gas measurements showed elevated H2S and CO2 emissions. On January 23, seismometers recorded 48 hrs of intermittent tremor and discrete, low-frequency to hybrid events. Over the next 6 weeks, seismicity waxed and waned, an estimated 5-6 million m3 of ice were lost due to melting, volcanic gas emissions increased, and debris flows emerged repeatedly from recently formed ice holes near the 1990 dome, located on the crater’s N (“Drift”) side. On March 15, a phreatic explosion deposited non-juvenile ash from a new vent in the summit ice cap just S of the 1990 dome. Ash from the explosion rose to ~4500 m above sea level (asl). The plume was accompanied by weak seismicity. The first magmatic explosion occurred on March 22. Over the next two weeks, more than 19 explosions destroyed at least two lava domes and

  5. Establishing the diagnostic criteria for eruption disorders based on genetic and clinical data.

    PubMed

    Rhoads, Stephanie Golubic; Hendricks, Heather M; Frazier-Bowers, Sylvia A

    2013-08-01

    Proper diagnosis and management of eruption disturbances remains challenging but is critical to a functional occlusion. The objective of this study was to establish definitive criteria to differentiate and diagnose eruption disorders, specifically primary failure of eruption (PFE) and ankylosis. Sixty-four affected persons were placed into 3 cohorts: PFE diagnosed through confirmed PTH1R mutation (n = 11), PFE diagnosed based on clinical criteria (n = 47), and ankylosis diagnosed based on clinical criteria (n = 6). These groups were assessed to identify clinical features that differentiate PFE and ankylosis. Ninety-three percent of the subjects in the genetic and clinical PFE cohorts combined (n = 58) and 100% in the genetic PFE cohort had at least 1 infraoccluded first permanent molar. Additionally, a novel functional PTH1R mutation, 1092delG, was identified and linked to PFE in the deciduous dentition. An infraoccluded, supracrestal first molar is a hallmark of PFE, often involving both arches in the permanent or deciduous dentition, and with unilateral or bilateral affection, infraoccluded second premolar or second molar, and multiple affected adjacent teeth. Our results further suggest that PFE and ankylosis might be clinically indistinguishable without knowledge of prior trauma, treatment history, genetic information, or obliteration of the periodontal ligament space. Copyright © 2013 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

  6. Comparing Viability of Periodontal Ligament Stem Cells Isolated From Erupted and Impacted Tooth Root.

    PubMed

    Dalband, Mohsen; Amiri, Iraj; Soltanian, Ali Reza; Gholami, Mehdi; Khayati, Adell; Keshmirypor, Vahid

    2015-10-01

    The aim of the study was to compare the viability of periodontal ligament-derived stem/progenitor cells (PDLSCs) from 2 different sources. Periodontal ligament (PDL) tissue was obtained from 20 surgically extracted human third molars and 20 healthy premolars extracted for orthodontic reasons. Periodontal ligament-derived stem/progenitor cells were isolated from 2 different PDL tissue sources and characterized by colony forming unit assay, cell surface marker characterizations, and their osteogenic differentiation potential. To determine cell viability within 2 groups, the colorimetric 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) metabolic activity assay was used. Data were statistically analyzed using independent t-test by SPSS 16 software (SPSS Inc, Chicago, IL). According to the MTT assay, the mean viability rate ± standard deviation of PDLSCs in the impacted third molar sample cells was 0.355 ± 0.411 and for erupted premolar sample cells was 0.331 ± 0.556. Based on One-Sample Kolmogorov-Smirnov test, P value for impacted and erupted teeth was 0.954 and 0.863, respectively. No statistical difference was seen between 2 groups. (P value > 0.05) CONCLUSIONS: Our results demonstrated that if surgical aseptic technique is a method employed to maintain asepsis, PDLSCs obtained from impacted and erupted tooth root would have the same viability rate.

  7. Incorporating the eruptive history in a stochastic model for volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Bebbington, Mark

    2008-08-01

    We show how a stochastic version of a general load-and-discharge model for volcanic eruptions can be implemented. The model tracks the history of the volcano through a quantity proportional to stored magma volume. Thus large eruptions can influence the activity rate for a considerable time following, rather than only the next repose as in the time-predictable model. The model can be fitted to data using point-process methods. Applied to flank eruptions of Mount Etna, it exhibits possible long-term quasi-cyclic behavior, and to Mauna Loa, a long-term decrease in activity. An extension to multiple interacting sources is outlined, which may be different eruption styles or locations, or different volcanoes. This can be used to identify an 'average interaction' between the sources. We find significant evidence that summit eruptions of Mount Etna are dependent on preceding flank eruptions, with both flank and summit eruptions being triggered by the other type. Fitted to Mauna Loa and Kilauea, the model had a marginally significant relationship between eruptions of Mauna Loa and Kilauea, consistent with the invasion of the latter's plumbing system by magma from the former.

  8. Automatic teeth axes calculation for well-aligned teeth using cost profile analysis along teeth center arch.

    PubMed

    Kim, Gyehyun; Lee, Jeongjin; Seo, Jinwook; Lee, Wooshik; Shin, Yeong-Gil; Kim, Bohyoung

    2012-04-01

    In dental implantology and virtual dental surgery planning using computed tomography (CT) images, the examination of the axes of neighboring and/or biting teeth is important to improve the performance of the masticatory system as well as the aesthetic beauty. However, due to its high connectivity to neighboring teeth and jawbones, a tooth and/or its axis is very elusive to automatically identify in dental CT images. This paper presents a novel method of automatically calculating individual teeth axes. The planes separating the individual teeth are automatically calculated using cost profile analysis along the teeth center arch. In this calculation, a novel plane cost function, which considers the intensity and the gradient, is proposed to favor the teeth separation planes crossing the teeth interstice and suppress the possible inappropriately detected separation planes crossing the soft pulp. The soft pulp and dentine of each individually separated tooth are then segmented by a fast marching method with two newly proposed speed functions considering their own specific anatomical characteristics. The axis of each tooth is finally calculated using principal component analysis on the segmented soft pulp and dentine. In experimental results using 20 clinical datasets, the average angle and minimum distance differences between the teeth axes manually specified by two dentists and automatically calculated by the proposed method were 1.94° ± 0.61° and 1.13 ± 0.56 mm, respectively. The proposed method identified the individual teeth axes accurately, demonstrating that it can give dentists substantial assistance during dental surgery such as dental implant placement and orthognathic surgery.

  9. Fracture resistance of posterior teeth restored with modern restorative materials

    PubMed Central

    Hamouda, Ibrahim M.; Shehata, Salah H.

    2011-01-01

    We studied the fracture resistance of maxillary premolars restored with recent restorative materials. Fifty maxillary premolars were divided into five groups: Group 1 were unprepared teeth; Group 2 were teeth prepared without restoration; Group 3 were teeth restored with tetric ceram HB; Group 4 were teeth restored with InTen S; and Group 5 were teeth restored with Admira. The samples were tested using a universal testing machine. Peak loads at fracture were recorded. The teeth restored with Admira had the highest fracture resistance followed by those restored with InTen-S and tetric ceram HB. Prepared, unrestored teeth were the weakest group. There was a significant difference between the fracture resistance of intact teeth and the prepared, unrestored teeth. There was also a significant difference among the tested restorative materials. Teeth restored with Admira showed no significant difference when compared with the unprepared teeth. It was concluded that the teeth restored with Admira exhibited the highest fracture resistance. PMID:23554719

  10. Eruption and degassing dynamics of the major August 2015 Piton de la Fournaise eruption

    NASA Astrophysics Data System (ADS)

    Di Muro, Andrea; Arellano, Santiago; Aiuppa, Alessandro; Bachelery, Patrick; Boudoire, Guillaume; Coppola, Diego; Ferrazzini, Valerie; Galle, Bo; Giudice, Gaetano; Gurioli, Lucia; Harris, Andy; Liuzzo, Marco; Metrich, Nicole; Moune, Severine; Peltier, Aline; Villeneuve, Nicolas; Vlastelic, Ivan

    2016-04-01

    Piton de la Fournaise (PdF) shield volcano is one of the most active basaltic volcanoes in the World with one eruption every nine months, on average. This frequent volcanic activity is broadly bimodal, with frequent small volume, short lived eruptions (< 30 Mm3, most being < 10 Mm3) and less frequent relatively large (50-210 Mm3) and long lasting (months) eruptions. After the major caldera forming event of 2007, the volcano produced several short lived small volume summit to proximal eruptions of relatively evolved cotectic magmas and relatively long repose periods (up to 3.5 years between 2010 and 2014). The August 2015 eruption was the first large (45±15 Mm3) and long lasting (2 months) eruption since 2007 and the only event to be fully monitored by the new gas geochemical network of Piton de la Fournaise volcanological observatory (DOAS, MultiGaS, diffuse CO2 soil emissions). Regular lava and tephra sampling was also performed for geochemical and petrological analysis. The eruption was preceded by a significant increase in CO2 soil emissions at distal soil stations (ca. 15 km from the summit), with CO2 enrichment also being recorded at summit low temperature fumaroles. Eruptive products were spectacularly zoned, with plagioclase and pyroxene being abundant in the early erupted products and olivine being the main phase in the late-erupted lavas. Total gas emissions at the eruptive vent underwent a decrease during the first half of the eruption and then an increase, mirroring the time evolution of magma discharge rate (from 5-10 m3/s in September to 15-30 m3/s in late-October) and the progressive change in magma composition. In spite of significant evolution in magma and gas output, CO2/SO2 ratios in high temperature gases remained quite low (< 0.3) and with little temporal change. Geochemical data indicated that this relatively long-lived eruption corresponded to the progressive drainage of most of the shallow part of PdF plumbing system, triggered by a new

  11. An estimation of magmatic system parameters from eruptive activity dynamics

    NASA Astrophysics Data System (ADS)

    Slezin, Yurii

    Eruptive activity dynamics characterizes the changes in eruptive regime over time. Eruptive activity can be characterized by: the relation between eruptions and repose periods, the mass flow rate of eruption, the type and structure of the erupted products, and their velocity at the conduit exit. These characteristics and their evolution over time depend on both the structure of the magmatic system and on some external factors. These factors define the boundary conditions and include the eruptive prehistory. This study deals with the inverse problem: reconstruction of the structure of the magmatic system using the eruptive activity dynamics. The critical role of the sharp jump-like changes in eruption regime and intensity described theoretically in [Slezin, 1983, 1984, 1998, 2003a] is emphasized and the additional information needed to obtain a unique solution is discussed. Using this inverse approach in conjunction with a "chamber-conduit" model, some geometrical parameters of the following magma systems were estimated: Shiveluch, Mt St Helens, and Bezymianny.

  12. Mount Cameroon Eruptions, Related Hazards and Effects on the Ecosystem

    NASA Astrophysics Data System (ADS)

    Aloatem Tazifor, A. N.

    2016-02-01

    Mount Cameroon (MC) is the highest peak in West and Central Africa. It is the only active volcano along the 1600km, Cameroon volcanic line with NE-SW orientation. It has a height of about 4100m above sea level, is a typical example of a hazardous volcano in a densely populated area, often causing damage by lava flows. It shows layered mafic volcanic sequence thought to be related to near-continuous eruptions within the last century during which period it has erupted 8 times in 1909, 1922, 1925, 1954, 1959, 1982, 1999 and 2000. These volcanic activities are suggested to be contributing factor to the many small-scale shallow landslides within the last 20 years which have resulted in the loss of about 30 lives and significant damage to farmland and property. The relatively high carbon dioxide (CO2) content in MC Glass inclusions support the interpretation that the CO2 gas responsible for the 1984 Lakes Monoun and 1986 Nyos disasters is magmatic in origin, which killed 37 and over 1800 people respectively. Months before the latest 2000 eruption, MC was characterized by a seismic swarm recorded in 03/2000 by analogue seismic stations. The co-eruptive period from May 28th to June 19th, 2000 was characterized by sequences of earth quakes, swarms and volcanic tremor. The main shock had a magnitude 3.2 event and a modified Mercalli intensity of 3 to 4. The largest seismic event recorded had a magnitude of 4. An explosion on 5th June, 2000, injured many members of a surveillance team, and a helicopter crash on 10th June, 2000 killed both pilots. It also led to lava flow across the Limbe-Idenau highway, damage of forest and palm plantations in Bakingili, and the evacuation of the 600 inhabitants of Bakingili. Never the less MC has positive impacts on the environment such as increased soil fertility where agro-industrial plantations have taken advantage, and more touristic sites have developed. After the last eruption of 2000, a number of seismographs have been placed along

  13. Premature primary tooth eruption in cognitive/motor-delayed ADNP-mutated children

    PubMed Central

    Gozes, I; Van Dijck, A; Hacohen-Kleiman, G; Grigg, I; Karmon, G; Giladi, E; Eger, M; Gabet, Y; Pasmanik-Chor, M; Cappuyns, E; Elpeleg, O; Kooy, R F; Bedrosian-Sermone, S

    2017-01-01

    A major flaw in autism spectrum disorder (ASD) management is late diagnosis. Activity-dependent neuroprotective protein (ADNP) is a most frequent de novo mutated ASD-related gene. Functionally, ADNP protects nerve cells against electrical blockade. In mice, complete Adnp deficiency results in dysregulation of over 400 genes and failure to form a brain. Adnp haploinsufficiency results in cognitive and social deficiencies coupled to sex- and age-dependent deficits in the key microtubule and ion channel pathways. Here, collaborating with parents/caregivers globally, we discovered premature tooth eruption as a potential early diagnostic biomarker for ADNP mutation. The parents of 44/54 ADNP-mutated children reported an almost full erupted dentition by 1 year of age, including molars and only 10 of the children had teeth within the normal developmental time range. Looking at Adnp-deficient mice, by computed tomography, showed significantly smaller dental sacs and tooth buds at 5 days of age in the deficient mice compared to littermate controls. There was only trending at 2 days, implicating age-dependent dysregulation of teething in Adnp-deficient mice. Allen Atlas analysis showed Adnp expression in the jaw area. RNA sequencing (RNAseq) and gene array analysis of human ADNP-mutated lymphoblastoids, whole-mouse embryos and mouse brains identified dysregulation of bone/nervous system-controlling genes resulting from ADNP mutation/deficiency (for example, BMP1 and BMP4). AKAP6, discovered here as a major gene regulated by ADNP, also links cognition and bone maintenance. To the best of our knowledge, this is the first time that early primary (deciduous) teething is related to the ADNP syndrome, providing for early/simple diagnosis and paving the path to early intervention/specialized treatment plan. PMID:28221363

  14. Premature primary tooth eruption in cognitive/motor-delayed ADNP-mutated children.

    PubMed

    Gozes, I; Van Dijck, A; Hacohen-Kleiman, G; Grigg, I; Karmon, G; Giladi, E; Eger, M; Gabet, Y; Pasmanik-Chor, M; Cappuyns, E; Elpeleg, O; Kooy, R F; Bedrosian-Sermone, S

    2017-02-21

    A major flaw in autism spectrum disorder (ASD) management is late diagnosis. Activity-dependent neuroprotective protein (ADNP) is a most frequent de novo mutated ASD-related gene. Functionally, ADNP protects nerve cells against electrical blockade. In mice, complete Adnp deficiency results in dysregulation of over 400 genes and failure to form a brain. Adnp haploinsufficiency results in cognitive and social deficiencies coupled to sex- and age-dependent deficits in the key microtubule and ion channel pathways. Here, collaborating with parents/caregivers globally, we discovered premature tooth eruption as a potential early diagnostic biomarker for ADNP mutation. The parents of 44/54 ADNP-mutated children reported an almost full erupted dentition by 1 year of age, including molars and only 10 of the children had teeth within the normal developmental time range. Looking at Adnp-deficient mice, by computed tomography, showed significantly smaller dental sacs and tooth buds at 5 days of age in the deficient mice compared to littermate controls. There was only trending at 2 days, implicating age-dependent dysregulation of teething in Adnp-deficient mice. Allen Atlas analysis showed Adnp expression in the jaw area. RNA sequencing (RNAseq) and gene array analysis of human ADNP-mutated lymphoblastoids, whole-mouse embryos and mouse brains identified dysregulation of bone/nervous system-controlling genes resulting from ADNP mutation/deficiency (for example, BMP1 and BMP4). AKAP6, discovered here as a major gene regulated by ADNP, also links cognition and bone maintenance. To the best of our knowledge, this is the first time that early primary (deciduous) teething is related to the ADNP syndrome, providing for early/simple diagnosis and paving the path to early intervention/specialized treatment plan.

  15. Thermal signature, eruption style, and eruption evolution at Pele and Pillan on Io

    USGS Publications Warehouse

    Davies, A.G.; Keszthelyi, L.P.; Williams, D.A.; Phillips, C.B.; McEwen, A.S.; Lopes, R.M.C.; Smythe, W.D.; Kamp, L.W.; Soderblom, L.A.; Carlson, R.W.

    2001-01-01

    The Galileo spacecraft has been periodically monitoring volcanic activity on Io since June 1996, making it possible to chart the evolution of individual eruptions. We present results of coanalysis of Near-Infrared Mapping Spectrometer (NIMS) and solid-state imaging (SSI) data of eruptions at Pele and Pillan, especially from a particularly illuminating data set consisting of mutually constraining, near-simultaneous NIMS and SSI observations obtained during orbit C9 in June 1997. The observed thermal signature from each hot spot, and the way in which the thermal signature changes with time, tightly constrains the possible styles of eruption. Pele and Pillan have very different eruption styles. From September 1996 through May 1999, Pele demonstrates an almost constant total thermal output, with thermal emission spectra indicative of a long-lived, active lava lake. The NIMS Pillan data exhibit the thermal signature of a "Pillanian" eruption style, a large, vigorous eruption with associated open channel, or sheet flows, producing an extensive flow field by orbit C10 in September 1997. The high mass eruption rate, high liquidus temperature (at least 1870 K) eruption at Pillan is the best candidate so far for an active ultramafic (magnesium-rich, "komatiitic") flow on Io, a style of eruption never before witnessed. The thermal output per unit area from Pillan is, however, consistent with the emplacement of large, open-channel flows. Magma temperature at Pele is ~1600 K. If the magma temperature is 1600 K, it suggests a komatiitic-basalt composition. The power output from Pele is indicative of a magma volumetric eruption rate of ~250 to 340 m3 s-1. Although the Pele lava lake is considerably larger than its terrestrial counterparts, the power and mass fluxes per unit area are similar to active terrestrial lava lakes. Copyright 2001 by the American Geophysical Union.

  16. Volcanic Eruptions at Mid-ocean Ridges and the Influence of Magma Supply on Eruption Dynamics

    NASA Astrophysics Data System (ADS)

    White, S. M.; McClinton, J. T.; Howell, J.; Sinton, J. M.; Colman, A.; Behn, M. D.; Gregg, T. K.

    2011-12-01

    Eruptions on the seafloor are notoriously difficult to observe, map, and document. As a result, the rates of volcanism and controlling factors are very poorly constrained for the Earth's largest volcanic system. In lieu of direct observation, lava morphology provides a remarkably good proxy of the eruptive dynamics on the seafloor, albeit only semi-quantitatively. Lava morphology has been shown to be sensitive to changes in local lava flow rate; resulting from a combination of vent effusion rate, seafloor slope, and lava viscosity; producing flatter, low-relief flows (sheets) at high flow rates and more rounded, higher relief lava flows (pillows) as rate decreases. Lava morphology also scales up so that pillows tend to build high-relief mounds and cones, while low-relief plains consist of mostly sheets and lobate flows. Armed with these basic relationships, we are able infer the typical rates of volcanic processes from morphology on a regional basis and within individual eruptive units. Hotspot-influenced spreading ridges allow us to examine the effects of magma supply independent of changes in spreading rate. Our results suggest that as magma supply decreases so do average eruption rates. However, the influence of magma supply on factors controlling lava morphology (e.g. lava viscosity) require additional study. Preliminary evidence also suggests that eruptions occur less frequently but are more often longer-lived and more voluminous as magma supply decreases, although much additional work is needed to constrain eruption size:frequency distribution at mid-ocean ridges. Some simple models of the relationship between effusion rate and magma reservoir depth support our inferences from lava morphology. Comparison of these predictions to the catalog of known eruptions at mid-ocean ridges supports the hypothesis that magma supply is an excellent first-order predictor of eruptive dynamics. Much work remains to be done on eruption dynamics, in particular increasing the

  17. Tooth development in a model reptile: functional and null generation teeth in the gecko Paroedura picta

    PubMed Central

    Zahradnicek, Oldrich; Horacek, Ivan; Tucker, Abigail S

    2012-01-01

    This paper describes tooth development in a basal squamate, Paroedura picta. Due to its reproductive strategy, mode of development and position within the reptiles, this gecko represents an excellent model organism for the study of reptile development. Here we document the dental pattern and development of non-functional (null generation) and functional generations of teeth during embryonic development. Tooth development is followed from initiation to cytodifferentiation and ankylosis, as the tooth germs develop from bud, through cap to bell stages. The fate of the single generation of non-functional (null generation) teeth is shown to be variable, with some teeth being expelled from the oral cavity, while others are incorporated into the functional bone and teeth, or are absorbed. Fate appears to depend on the initiation site within the oral cavity, with the first null generation teeth forming before formation of the dental lamina. We show evidence for a stratum intermedium layer in the enamel epithelium of functional teeth and show that the bicuspid shape of the teeth is created by asymmetrical deposition of enamel, and not by folding of the inner dental epithelium as observed in mammals. PMID:22780101

  18. Tooth development in a model reptile: functional and null generation teeth in the gecko Paroedura picta.

    PubMed

    Zahradnicek, Oldrich; Horacek, Ivan; Tucker, Abigail S

    2012-09-01

    This paper describes tooth development in a basal squamate, Paroedura picta. Due to its reproductive strategy, mode of development and position within the reptiles, this gecko represents an excellent model organism for the study of reptile development. Here we document the dental pattern and development of non-functional (null generation) and functional generations of teeth during embryonic development. Tooth development is followed from initiation to cytodifferentiation and ankylosis, as the tooth germs develop from bud, through cap to bell stages. The fate of the single generation of non-functional (null generation) teeth is shown to be variable, with some teeth being expelled from the oral cavity, while others are incorporated into the functional bone and teeth, or are absorbed. Fate appears to depend on the initiation site within the oral cavity, with the first null generation teeth forming before formation of the dental lamina. We show evidence for a stratum intermedium layer in the enamel epithelium of functional teeth and show that the bicuspid shape of the teeth is created by asymmetrical deposition of enamel, and not by folding of the inner dental epithelium as observed in mammals. © 2012 The Authors. Journal of Anatomy © 2012 Anatomical Society.

  19. Allogeneic stem cells derived from human exfoliated deciduous teeth (SHED) for the management of periapical lesions in permanent teeth: Two case reports of a novel biologic alternative treatment.

    PubMed

    Prasad, Madu Ghana Shyam; Ramakrishna, Juvva; Babu, Duvvi Naveen

    2017-01-01

    Stem cells are the pluripotent cells that have the capacity to differentiate into other specialized cells. Recently, many experiments have been conducted to study the potentiality of stem cells in the tissue regeneration. We report two cases treated utilizing stem cells from human exfoliated deciduous teeth (SHED) in the management of periapical lesions in permanent teeth. Two normal human deciduous teeth from children, 7‒8 years of age, were collected to isolate stem cells. Two patients, one with periapical pathology alone and the other with periapical lesion along with an open apex in young permanent teeth, were selected for the study. After initial debridement of the root canals, homing of SHED was carried out and the access cavity was sealed using glass-ionomer cement. Clinical examination after 7 days, 30 days, 90 days, 180 days and 365 days revealed no symptoms. Closure of open apex and periapical tissue healing were observed radiographically at one-month review and maintained until 365-day review. Positive response to electric pulp testing was recorded for the treated teeth from the 3- to 12-month follow-ups. The treated cases demonstrated complete resolution of periapical radiolucency in a span of 30 days, which was faster than the conventional methods. SHED could be considred effective in treating the periapical lesions and open apex in permanent teeth.

  20. Eruption precursors: Manifestations and strategies for detection

    NASA Astrophysics Data System (ADS)

    Poland, Michael; Pritchard, Matthew

    2017-04-01

    The past several decades have seen a rapid increase in volcano monitoring and modeling capabilities. Diverse arrays of instrument networks can detect a variety of pre-, co-, and post-eruptive phenomena, and remote sensing observations are available across a range of spatial, temporal, and spectral resolutions. A growing class of models, based on the physics of magmatic systems, are making use of these expanding datastreams, providing probabilistic assessments of such parameters as magma supply, volatile content, and eruption duration. To what extent, however, do these developments heighten our ability to identify eruption precursors? The advent of better data and new models provides an opportunity to reexamine our understanding of pre-eruption unrest, as well as our ability to detect and recognize it as such. An idealized model of the buildup to a volcanic eruption might include magma ascent from a deep source region and accumulation in the mid- to upper crust in the preceding months to years. The process might be manifested by surface inflation and deep long-period earthquakes, and accompanied by an increase in CO2 emissions. As magma continues to accumulate, distal volcano-tectonic earthquakes may result as stress builds on nearby faults, H2S emissions may increase as sulfur in a shallow reservoir is hydrolyzed by groundwater, and fumarole and spring temperatures may increase and show changes in chemistry. In the days to hours before an eruption, sudden changes in the rate and style of earthquakes (including repeating earthquakes and tremor) and deformation may occur as the magma reservoir ruptures and magma moves laterally or vertically. Phreatic eruptions might result as ascending magma comes into contact with groundwater, and SO2 emissions might increase as the path between the magma and surface dries out. How often does such a sequence actually occur? Relatively few volcanoes are comprehensively monitored prior to obvious expressions of unrest, so this is not

  1. Romundina and the evolutionary origin of teeth.

    PubMed

    Rücklin, Martin; Donoghue, Philip C J

    2015-06-01

    Theories on the origin of vertebrate teeth have long focused on chondrichthyans as reflecting a primitive condition-but this is better informed by the extinct placoderms, which constitute a sister clade or grade to the living gnathostomes. Here, we show that 'supragnathal' toothplates from the acanthothoracid placoderm Romundina stellina comprise multi-cuspid teeth, each composed of an enameloid cap and core of dentine. These were added sequentially, approximately circumferentially, about a pioneer tooth. Teeth are bound to a bony plate that grew with the addition of marginal teeth. Homologous toothplates in arthrodire placoderms exhibit a more ordered arrangement of teeth that lack enameloid, but their organization into a gnathal, bound by layers of cellular bone associated with the addition of each successional tooth, is the same. The presence of enameloid in the teeth of Romundina suggests that it has been lost in other placoderms. Its covariation in the teeth and dermal skeleton of placoderms suggests a lack of independence early in the evolution of jawed vertebrates. It also appears that the dentition-manifest as discrete gnathal ossifications-was developmentally discrete from the jaws during this formative episode of vertebrate evolution.

  2. Current status of nylon teeth myth in Tanzania: a cross sectional study.

    PubMed

    Mugonzibwa, Emeria Abella; Kahabuka, Febronia Kokulengya; Mwalutambi, Samwel Charles; Kikwilu, Emil Namakuka

    2018-01-10

    Nylon teeth myth is a belief of associating infant illnesses with bulges on infants' alveolus that mark the positions of underlying developing teeth and that it is necessary to treat the condition mainly by traditional healers to prevent infant death. The traditional treatment often leads to serious complications that may lead to infant death. Although the government instituted educational campaigns against the myth in 1980s to 1990s, to date, repeated unpublished reports from different parts of the country indicate continued existence of the myth. Therefore, this study aimed to assess the current status of the nylon teeth myth in Tanzania. The study population was obtained using the WHO Oral Health pathfinder methodology. A structured questionnaire inquired about socio-demographics as well as experiences with "nylon teeth" myth and its related practices. Odds ratios relating to knowledge and experience of the nylon teeth myth were estimated. A total of 1359 respondents aged 17 to 80 years participated in the study. 614 (45%) have heard of nylon teeth myth, of whom 46.1% believed that nylon teeth is a reality, and 42.7% reported existence of the myth at the time of study. Being residents in regions where nylon teeth myth was known before 1990 (OR = 8.39 (6.50-10.83), p < 0.001) and/or hospital worker (OR = 2.97 (1.99-4.42), p < 0.001) were associated with having have heard of nylon teeth myth. Proportionately more residents in regions where nylon teeth myth was not known before 1990 (p < 0.001), the educated (p < 0.001) and hospital workers (p < 0.001) believed modern medicine, whereas, proportionately more residents in regions where nylon teeth was known before 1990 (p < 0.001), less educated (p < 0.001) and non-hospital workers (p < 0.001) believed traditional medicine to be the best treatment for symptoms related to nylon teeth myth respectively. The "nylon teeth" myth still exists in Tanzania; a substantial proportion

  3. Russian eruption warning systems for aviation

    USGS Publications Warehouse

    Neal, C.; Girina, O.; Senyukov, S.; Rybin, A.; Osiensky, J.; Izbekov, P.; Ferguson, G.

    2009-01-01

    More than 65 potentially active volcanoes on the Kamchatka Peninsula and the Kurile Islands pose a substantial threat to aircraft on the Northern Pacific (NOPAC), Russian Trans-East (RTE), and Pacific Organized Track System (PACOTS) air routes. The Kamchatka Volcanic Eruption Response Team (KVERT) monitors and reports on volcanic hazards to aviation for Kamchatka and the north Kuriles. KVERT scientists utilize real-time seismic data, daily satellite views of the region, real-time video, and pilot and field reports of activity to track and alert the aviation industry of hazardous activity. Most Kurile Island volcanoes are monitored by the Sakhalin Volcanic Eruption Response Team (SVERT) based in Yuzhno-Sakhalinsk. SVERT uses daily moderate resolution imaging spectroradiometer (MODIS) satellite images to look for volcanic activity along this 1,250-km chain of islands. Neither operation is staffed 24 h per day. In addition, the vast majority of Russian volcanoes are not monitored seismically in real-time. Other challenges include multiple time-zones and language differences that hamper communication among volcanologists and meteorologists in the US, Japan, and Russia who share the responsibility to issue official warnings. Rapid, consistent verification of explosive eruptions and determination of cloud heights remain significant technical challenges. Despite these difficulties, in more than a decade of frequent eruptive activity in Kamchatka and the northern Kuriles, no damaging encounters with volcanic ash from Russian eruptions have been recorded. ?? Springer Science+Business Media B.V. 2009.

  4. The study of barium concentration in deciduous teeth, impacted teeth, and facial bones of Polish residents.

    PubMed

    Fischer, Agnieszka; Malara, Piotr; Wiechuła, Danuta

    2014-10-01

    The study determines the concentration of Ba in mineralized tissues of deciduous teeth, permanent impacted teeth, and facial bones. The study covers the population of children and adults (aged 6-78) living in an industrial area of Poland. Teeth were analyzed in whole, with no division into dentine and enamel. Facial bones and teeth were subjected to the following preparation: washing, drying, grinding in a porcelain mortar, sample weighing (about 0.2 g), and microwave mineralization with spectrally pure nitric acid. The aim of the study was to determinate the concentration of Ba in deciduous teeth, impacted permanent teeth, and facial bones. The concentration of barium in samples was determined over the ICP OES method. The Ba concentration in the tested bone tissues amounted to 2.2-15.5 μg/g (6.6 μg/g ± 3.9). The highest concentration of Ba was present in deciduous teeth (10.5 μg/g), followed by facial bones (5.2 μg/g), and impacted teeth (4.3 μg/g) (ANOVA Kruskal-Wallis rank test, p = 0.0002). In bone tissue and impacted teeth, Ba concentration increased with age. In deciduous teeth, the level of Ba decreased with children's age.

  5. Ash from Changbaishan Millennium eruption recorded in Greenland ice: Implications for determining the eruption's timing and impact

    NASA Astrophysics Data System (ADS)

    Sun, Chunqing; Plunkett, Gill; Liu, Jiaqi; Zhao, Hongli; Sigl, Michael; McConnell, Joseph R.; Pilcher, Jonathan R.; Vinther, Bo; Steffensen, J. P.; Hall, Valerie

    2014-01-01

    Major volcanic eruptions can impact on global climate by injecting large quantities of aerosols and ash into the atmosphere that alter the radiative balance and chemical equilibrium of the stratosphere. The Millennium eruption of Tianchi (Paektu), China/North Korea, was one of the largest Late Holocene eruptions. Uncertainty about the precise timing of the eruption has hindered the recognition of its climate impact in palaeoclimate and historical records. Here we report the compelling identification of the eruption's volcanic signal in Greenland ice cores through the association of geochemically characterized volcanic glass, represented in by bimodal populations that compare with proximal material from the source eruption. The eruption most probably occurred in the A.D. 940s, 7 years after the Eldgjá eruption on Iceland. We examine the eruption's potential for climate forcing using the sulfate records from the ice cores and conclude that it was unlikely to have had a global or extraregional impact.

  6. Are Avellino (4365 cal BP) and Pompeii twin plinian eruptions? Pre-eruptive constraints and degassing history

    NASA Astrophysics Data System (ADS)

    Boudon, Georges; Balcone-Boissard, Hélène; Villemant, Benoît.; Ucciani, Guillaume; Cioni, Raffaello

    2010-05-01

    Somma-Vesuvius activity started 35 ky ago and is characterized by numerous eruptions of variable composition and eruptive style, sometimes interrupted by long periods of unrest. The main explosive eruptions are represented by four plinian eruptions: Pomici di Base eruption (22 cal ky), Mercato (~8900 cal BP), Avellino (4365 cal BP) and Pompeii (79 AD). The 79 AD eruption embodies the most famous eruption since it's responsible of the destruction of Pompeii and Herculanum and it's the first described eruption. The Avellino eruption represents the last plinian event that preceded the Pompeii eruption. The eruptive sequence is similar to the 79 AD plinian eruption, with an opening phase preceding a main plinian fallout activity which ended by a phreatomagmatic phase. The fallout deposit displays a sharp colour contrast from white to grey pumice, corresponding to a magma composition evolution. We focus our study on the main fallout deposit that we sampled in detail in the Traianello quarry, 9 km North-North East of the crater, to investigate the degassing processes during the eruption, using volatile content and textural observations. Density and vesicularity measurements were obtained on a minimum of 100 pumice clasts sampled in 10 stratigraphic levels in the fallout deposit. On the basis of the density distribution, bulk geochemical data, point analytical measurements on glasses (melt inclusions and residual glass) and textural observations were obtained simultaneously on a minimum of 5 pumice clasts per eruptive unit. The glass composition, in particular the Na/K ratio, evolves from Na-rich phonolite for white pumices to a more K-rich phonolite for grey pumices. The pre-eruptive conditions are constrained by systematic Cl measurements in melt inclusions and matrix glass of pumice clasts. The entire magma was saturated relative to sub-critical fluids (a Cl-rich H2O vapour phase and a brine), with a Cl melt content buffered at ~6000 ppm, and a mean pre-eruptive H2O

  7. Post-eruptive Submarine Terrace Development of Capelinhos, Azores

    NASA Astrophysics Data System (ADS)

    Zhongwei Zhao, Will; Mitchell, Neil; Quartau, Rui; Tempera, Fernando; Bricheno, Lucy

    2017-04-01

    Erosion of the coasts of volcanic islands by waves creates shallow banks, but how erosion proceeds with time to create them and how it relates to wave climate is unclear. In this study, historical and recent marine geophysical data collected around the Capelinhos promontory (western Faial Island, Azores) offer an unusual opportunity to characterize how a submarine terrace developed after the eruption. The promontory was formed in 1957/58 during a Surtseyan eruption that terminated with extensive lava forming new rocky coastal cliffs. Historical measurements of coastline position are supplemented here with coastlines measured from 2004 and 2014 Google Earth images in order to characterize coastline retreat rate and distance for lava- and tephra-dominated cliffs. Swath mapping sonars were used to characterize the submarine geometry of the resulting terrace (terrace edge position, gradient and morphology). Limited photographs are available from a SCUBA dive and drop-down camera deployments to ground truth the submarine geomorphology. The results reveal that coastal retreat rates have decreased rapidly with the time after the eruption, possibly explained by the evolving resistance to erosion of cliff base materials. Surprisingly, coastline retreat rate decreases with terrace width in a simple inverse power law with terrace width. We suspect this is only a fortuitous result as wave attenuation over the terrace will not obviously produce the variation, but nevertheless it shows how rapidly the retreat rate declines. Understanding the relationship between terrace widening shelf and coastal cliff retreat rate may be more widely interesting if they can be used to understand how islands evolve over time into abrasional banks and guyots.

  8. Rugometric and microtopographic inspection of teeth enamel

    NASA Astrophysics Data System (ADS)

    Costa, Manuel F.; Pereira, Pedro B.

    2013-06-01

    The roughness of teeth' enamel is an important parameter in orthodontics. One example is the application in the process of decreasing tooth-size by reducing the interproximal enamel surfaces (stripping) of teeth. In order to achieve smooth surfaces clinicians have been testing various methods and progressively improved this therapeutic technique. The evaluation the surface roughness following teeth interproximal reduction is fundamental in the process. In general tooth' surface is not flat presenting a variety of complex geometries. In this communication we will report on the metrological procedure employed on the rugometric and microtopographic inspection by optical active triangulation of raw and processed (interproximal stripping) tooth surfaces.

  9. [Post and core for endodontically treated teeth].

    PubMed

    Labropoulou-Tzortzopoulou, E

    1990-01-01

    The literature is replete with the various techniques used in the restoration of pulpless teeth. Controversies surround the most clinically successful procedures and general dentist is confronted daily with the dilemma of choosing the best treatment modality. Endodontically treated posterior teeth present restorative problems. The remaining tooth tissue requires special treatment to prevent further destruction. This report presents an effective method for succeeding extension and protection for endodontically treated teeth. The advantages of the post-core system against other types of restoration, as well the indications are reviewed. In this paper the preparation of the tooth and the construction of a post-core by the direct and indirect method are described.

  10. [The treatment of injured front teeth].

    PubMed

    Wegelin, H

    1978-06-01

    Prefabricated steel crowns have been in use up to now as a classical method of preserving of fractured front teeth. They are, however, unsatisfactory for esthetical reasons. With the introduction to the acid etch technique incisal restorations have been made with composites. They are, however, subject to some abrasion and surface staining, as the inorganic filler particles loosen from the organic matrix. The clinical experiences with the new dental filling material Isosit lead to an esthetically and functionally accurate restoration of broken teeth or hypoplasia. After one year of observation 28 traumatically damaged teeth built up with Isocap have shown no marginal discoloration, staining or material loss.

  11. Arizona-sized Io Eruption

    NASA Technical Reports Server (NTRS)

    1997-01-01

    These images of Jupiter's volcanic moon, Io, show the results of a dramatic event that occurred on the fiery satellite during a five-month period. The changes, captured by the solid state imaging (CCD) system on NASA's Galileo spacecraft, occurred between the time Galileo acquired the left frame, during its seventh orbit of Jupiter, and the right frame, during its tenth orbit. A new dark spot, 400 kilometers (249 miles) in diameter, which is roughly the size of Arizona, surrounds a volcanic center named Pillan Patera. Galileo imaged a 120 kilometer (75 mile) high plume erupting from this location during its ninth orbit. Pele, which produced the larger plume deposit southwest of Pillan, also appears different than it did during the seventh orbit, perhaps due to interaction between the two large plumes. Pillan's plume deposits appear dark at all wavelengths. This color differs from the very red color associated with Pele, but is similar to the deposits of Babbar Patera, the dark feature southwest of Pele. Some apparent differences between the images are not caused by changes on Io's surface, but rather are due to differences in illumination, emission and phase angles. This is particularly apparent at Babbar Patera.

    North is to the top of the images. The left frame was acquired on April 4th, 1997, while the right frame was taken on Sept. 19th, 1997. The images were obtained at ranges of 563,000 kilometers (350,000 miles) for the left image, and 505,600 kilometers (314,165 miles) for the right.

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC.

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo.

  12. Influence of eruption stage and biofilm accumulation on occlusal caries in permanent molars: a generalized estimating equations logistic approach.

    PubMed

    Zenkner, J E A; Alves, L S; de Oliveira, R S; Bica, R H; Wagner, M B; Maltz, M

    2013-01-01

    The aim of this study was to estimate the independent effects of biofilm accumulation and eruption stage on the occurrence of active caries lesions on occlusal surfaces of permanent molars. The sample consisted of 298 schoolchildren (6-15 years) who were examined by a calibrated examiner at a dental unit, using artificial light, a dental mirror and a WHO probe. The occurrence of visible biofilm on occlusal surfaces and the eruption stage of each permanent molar were recorded. After professional prophylaxis and air drying, the occlusal surfaces were classified as sound, caries-inactive or caries-active. To evaluate the association of eruption stage and biofilm accumulation with active caries lesions, a logistic regression model was used. Since data were clustered, odds ratios were obtained using generalized estimating equations with a logistic link function. 1,779 permanent molars were examined. All eruption stages were associated with active caries lesions. After adjustment for biofilm accumulation and type of molar, molars with occlusal surfaces partially exposed to the oral cavity were 63.6 times more susceptible to caries activity than molars with full occlusion (95% CI = 22.0-183.7). After adjustment for eruption stage and type of molar, teeth with a high degree of biofilm accumulation were 14.5 times more susceptible to caries activity than those without visible biofilm accumulation (95% CI = 6.5-32.4). No association between active caries and hardly detectable biofilm was found in this population. The present study found that the eruption stage of permanent molars is strongly associated with active caries lesions, adjusted for biofilm accumulation and type of molar. Copyright © 2012 S. Karger AG, Basel.

  13. Manipulation of Fgf and Bmp signaling in teleost fishes suggests potential pathways for the evolutionary origin of multicuspid teeth.

    PubMed

    Jackman, William R; Davies, Shelby H; Lyons, David B; Stauder, Caitlin K; Denton-Schneider, Benjamin R; Jowdry, Andrea; Aigler, Sharon R; Vogel, Scott A; Stock, David W

    2013-01-01

    Teeth with two or more cusps have arisen independently from an ancestral unicuspid condition in a variety of vertebrate lineages, including sharks, teleost fishes, amphibians, lizards, and mammals. One potential explanation for the repeated origins of multicuspid teeth is the existence of multiple adaptive pathways leading to them, as suggested by their different uses in these lineages. Another is that the addition of cusps required only minor changes in genetic pathways regulating tooth development. Here we provide support for the latter hypothesis by demonstrating that manipulation of the levels of Fibroblast growth factor (Fgf) or Bone morphogenetic protein (Bmp) signaling produces bicuspid teeth in the zebrafish (Danio rerio), a species lacking multicuspid teeth in its ancestry. The generality of these results for teleosts is suggested by the conversion of unicuspid pharyngeal teeth into bicuspid teeth by similar manipulations of the Mexican Tetra (Astyanax mexicanus). That these manipulations also produced supernumerary teeth in both species supports previous suggestions of similarities in the molecular control of tooth and cusp number. We conclude that despite their apparent complexity, the evolutionary origin of multicuspid teeth is positively constrained, likely requiring only slight modifications of a pre-existing mechanism for patterning the number and spacing of individual teeth. © 2013 Wiley Periodicals, Inc.

  14. Manipulation of Fgf and Bmp signaling in teleost fishes suggests potential pathways for the evolutionary origin of multicuspid teeth

    PubMed Central

    Jackman, William R; Davies, Shelby H; Lyons, David B; Stauder, Caitlin K; Denton-Schneider, Benjamin R; Jowdry, Andrea; Aigler, Sharon R; Vogel, Scott A; Stock, David W

    2014-01-01

    Teeth with two or more cusps have arisen independently from an ancestral unicuspid condition in a variety of vertebrate lineages, including sharks, teleost fishes, amphibians, lizards, and mammals. One potential explanation for the repeated origins of multicuspid teeth is the existence of multiple adaptive pathways leading to them, as suggested by their different uses in these lineages. Another is that the addition of cusps required only minor changes in genetic pathways regulating tooth development. Here we provide support for the latter hypothesis by demonstrating that manipulation of the levels of Fibroblast growth factor (Fgf) or Bone morphogenetic protein (Bmp) signaling produces bicuspid teeth in the zebrafish (Danio rerio), a species lacking multicuspid teeth in its ancestry. The generality of these results for teleosts is suggested by the conversion of unicuspid pharyngeal teeth into bicuspid teeth by similar manipulations of the Mexican Tetra (Astyanax mexicanus). That these manipulations also produced supernumerary teeth in both species supports previous suggestions of similarities in the molecular control of tooth and cusp number. We conclude that despite their apparent complexity, the evolutionary origin of multicuspid teeth is positively constrained, likely requiring only slight modifications of a pre-existing mechanism for patterning the number and spacing of individual teeth. PMID:25098636

  15. Morphologic characteristics, location, and associated complications of maxillary and mandibular supernumerary teeth as evaluated using cone beam computed tomography.

    PubMed

    Mossaz, Jessica; Kloukos, Dimitrios; Pandis, Nikolaos; Suter, Valerie G A; Katsaros, Christos; Bornstein, Michael M

    2014-12-01

    To evaluate the location and morphologic characteristics of supernumerary teeth and to assess the frequency and extent of root resorption of adjacent teeth using cone beam computed tomography (CBCT). CBCT scans of 82 patients with supernumerary teeth in the maxilla and mandible were evaluated by two orthodontists independently. Data regarding the type, shape, and three-dimensional (3D) location of the supernumeraries including the frequency and extent of root resorption of adjacent teeth were recorded and evaluated for possible associations. The study comprised a total of 101 supernumerary teeth. Most of the patients (80.5 per cent) exhibited one single supernumerary tooth, while 15.8 per cent had two and 3.7 per cent had three supernumeraries. Males were affected more than females with a ratio of 1.65:1. Mesiodentes were the most frequently diagnosed type of supernumerary teeth (48.52 per cent), followed by supernumerary premolars (23.76 per cent) and lateral incisors (18.81 per cent). Supernumeraries were most commonly conical in shape (42.6 per cent) with a normal or inclined vertical position (61.4 per cent). Root resorption of adjacent teeth was detected for 22.8 per cent of the supernumerary teeth, most frequently for supernumerary premolars. There was a significant association between root resorption of adjacent teeth and type and shape of tooth. Interrater agreement for the measurements performed showed kappa values ranging from 0.55 to 1 with a kappa value of 1 for type and shape of the supernumerary teeth. CBCT provides 3D information about location and shape of supernumerary teeth as well as prevalence and degree of root resorption of neighbouring teeth with moderate to high interrater correlation. © The Author 2014. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  16. Lava Flow Hazard Modeling during the 2014-2015 Fogo eruption, Cape Verde

    NASA Astrophysics Data System (ADS)

    Del Negro, C.; Cappello, A.; Ganci, G.; Calvari, S.; Perez, N. M.; Hernandez Perez, P. A.; Victoria, S. S.; Cabral, J.

    2015-12-01

    Satellite remote sensing techniques and lava flow forecasting models have been combined to allow an ensemble response during effusive crises at poorly monitored volcanoes. Here, we use the HOTSAT volcano hot spot detection system that works with satellite thermal infrared data and the MAGFLOW lava flow emplacement model that considers the way in which effusion rate changes during an eruption, to forecast lava flow hazards during the 2014-2015 Fogo eruption. In many ways this was one of the major effusive eruption crises of recent years, since the lava flows actually invaded populated areas. HOTSAT is used to promptly analyze MODIS and SEVIRI data to output hot spot location, lava thermal flux, and effusion rate estimation. We use this output to drive the MAGFLOW simulations of lava flow paths and to update continuously flow simulations. Satellite-derived TADR estimates can be obtained in real time and lava flow simulations of several days of eruption can be calculated in a few minutes, thus making such a combined approach of paramount importance to provide timely forecasts of the areas that a lava flow could possibly inundate. In addition, such forecasting scenarios can be continuously updated in response to changes in the eruptive activity as detected by satellite imagery. We also show how Landsat-8 OLI and EO-1 ALI images complement the field observations for tracking the flow front position through time, and add considerable data on lava flow advancement to validate the results of numerical simulations. Our results thus demonstrate how the combination of satellite remote sensing and lava flow modeling can be effectively used during eruptive crises to produce realistic lava flow hazard scenarios and for assisting local authorities in making decisions during a volcanic eruption.

  17. “Explosive energy” during volcanic eruptions from fractal analysis of pyroclasts

    NASA Astrophysics Data System (ADS)

    Kueppers, Ulrich; Perugini, Diego; Dingwell, Donald B.

    2006-08-01

    Despite recent advances by means of experiments and high-resolution surveys and the growing understanding of the physical processes before and during volcanic eruptions, duration and type of eruptive activity still remain highly unpredictable. This uncertainty hinders appropriate hazard and associated risk assessment tremendously. In an effort to counter this problem, experimentally generated pyroclasts have been studied by fractal statistics with the aim of evaluating possible relationships between eruption energy and fragmentation efficiency. Rapid decompression experiments have been performed on three differently porous sample sets of the 1990-1995 eruption of Unzen volcano (Japan) at 850 °C and at initial pressure values above the respective fragmentation threshold [U. Kueppers, B. Scheu, O. Spieler, D.B. Dingwell, Fragmentation efficiency of explosive volcanic eruptions: a study of experimentally generated pyroclasts. J. Volcanol. Geotherm. Res. 153 (2006) 125-135.,O. Spieler, B. Kennedy, U. Kueppers, D.B. Dingwell, B. Scheu, J. Taddeucci, The fragmentation threshold of pyroclastic rocks. EPSL 226 (2004) 139-148.]. The size distribution of generated pyroclasts has been studied by fractal fragmentation theory and the fractal dimension of fragmentation ( Df), a value quantifying the intensity of fragmentation, has been measured for each sample. Results show that size distribution of pyroclastic fragments follows a fractal law (i.e. power-law) in the investigated range of fragment sizes, indicating that fragmentation of experimental samples reflects a scale-invariant mechanism. In addition, Df is correlated positively with the potential energy for fragmentation (PEF) while showing a strong influence of the open porosity of the samples. Results obtained in this work indicate that fractal fragmentation theory may allow for quantifying fragmentation processes during explosive volcanic eruptions by calculating the fractal dimension of the size distribution of

  18. Eruption of Alaska volcano breaks historic pattern

    USGS Publications Warehouse

    Larsen, Jessica; Neal, Christina A.; Webley, Peter; Freymueller, Jeff; Haney, Matthew; McNutt, Stephen; Schneider, David; Prejean, Stephanie; Schaefer, Janet; Wessels, Rick L.

    2009-01-01

    In the late morning of 12 July 2008, the Alaska Volcano Observatory (AVO) received an unexpected call from the U.S. Coast Guard, reporting an explosive volcanic eruption in the central Aleutians in the vicinity of Okmok volcano, a relatively young (~2000-year-old) caldera. The Coast Guard had received an emergency call requesting assistance from a family living at a cattle ranch on the flanks of the volcano, who reported loud "thunder," lightning, and noontime darkness due to ashfall. AVO staff immediately confirmed the report by observing a strong eruption signal recorded on the Okmok seismic network and the presence of a large dark ash cloud above Okmok in satellite imagery. Within 5 minutes of the call, AVO declared the volcano at aviation code red, signifying that a highly explosive, ash-rich eruption was under way.

  19. NASA Spacecraft Views Erupting Chilean Volcano

    NASA Image and Video Library

    2015-03-13

    On March 3, 2015, Chile's Villarrica volcano erupted, forcing the evacuation of thousands of people. The eruption deposited a layer of ash over the volcano's eastern slope, blanketing and darkening the normal winter snow cover. The eruption and its effects were captured by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument on NASA's Terra spacecraft on March 9. Black flows on the other flanks are mud and ash flows. Vegetation is displayed in red colors. The thermal infrared image shows hot spots (white colored) at the summit crater, indicating continuing volcanic activity. The ash blanket is warmer (brighter) than the cold snow (black). The image covers an area of 13.5 by 16.5 kilometers, and is located at 39.4 degrees south, 71.9 degrees west. http://photojournal.jpl.nasa.gov/catalog/PIA19241

  20. The giant keyhole limpet radular teeth: A naturally-grown harvest machine

    PubMed Central

    Ukmar-Godec, Tina; Kapun, Gregor; Zaslansky, Paul; Faivre, Damien

    2015-01-01

    The limpet radula is a feeding organ, which contains more than 100 rows of teeth. During their growth the teeth mature and advance in position along the radula. The simpler doccoglossan radulae operate by grinding rocky substrates, extracting the algae by rasping and scraping with the teeth functioning as shovels. Less is known about the rhipidoglossan radulae, used as rakes or brooms that brush and collect loose marine debris. This type of radula is found in the giant keyhole limpet (Megathura crenulata). The large size of this organism suggests that the rhipidoglossan radula entails a technological superiority for M. crenulata in its habitat. The structure and function of the radulae teeth have however not been reported in detail. Using a combination of 2D and 3D microscopy techniques coupled with amino acid analysis and X-ray scattering, we reveal the working components of M. crenulata’s radula. It is characterized by numerous marginal teeth surrounding a pair of major hook-like lateral teeth, two pairs of minor lateral teeth and a large central tooth. The mature major lateral teeth show pronounced signs of wear, which gradually increase towards the very front end of the radula and are evidence for scraping. An abrupt change in the amino acid composition in the major lateral teeth and the concurrent formation of a chitinous fiber-network mark the onset of tooth maturation. In comparison to the simpler rock-scraping doccoglossate limpets, the radula of M. crenulata forms an elaborate feeding apparatus, which can be seen as a natural harvest machine. PMID:26433029

  1. The giant keyhole limpet radular teeth: A naturally-grown harvest machine.

    PubMed

    Ukmar-Godec, Tina; Kapun, Gregor; Zaslansky, Paul; Faivre, Damien

    2015-12-01

    The limpet radula is a feeding organ, which contains more than 100 rows of teeth. During their growth the teeth mature and advance in position along the radula. The simpler doccoglossan radulae operate by grinding rocky substrates, extracting the algae by rasping and scraping with the teeth functioning as shovels. Less is known about the rhipidoglossan radulae, used as rakes or brooms that brush and collect loose marine debris. This type of radula is found in the giant keyhole limpet (Megathura crenulata). The large size of this organism suggests that the rhipidoglossan radula entails a technological superiority for M. crenulata in its habitat. The structure and function of the radulae teeth have however not been reported in detail. Using a combination of 2D and 3D microscopy techniques coupled with amino acid analysis and X-ray scattering, we reveal the working components of M. crenulata's radula. It is characterized by numerous marginal teeth surrounding a pair of major hook-like lateral teeth, two pairs of minor lateral teeth and a large central tooth. The mature major lateral teeth show pronounced signs of wear, which gradually increase towards the very front end of the radula and are evidence for scraping. An abrupt change in the amino acid composition in the major lateral teeth and the concurrent formation of a chitinous fiber-network mark the onset of tooth maturation. In comparison to the simpler rock-scraping doccoglossate limpets, the radula of M. crenulata forms an elaborate feeding apparatus, which can be seen as a natural harvest machine. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  2. Environmental influences on the trace element content of teeth--implications for disease and nutritional status.

    PubMed

    Brown, Catriona J; Chenery, Simon R N; Smith, Barry; Mason, Carol; Tomkins, Andrew; Roberts, Graham J; Sserunjogi, Louise; Tiberindwa, John V

    2004-09-01

    The aim of this study was to compare the trace element content of children's primary teeth from Uganda and the UK. The Ugandan teeth were from children living in an area where endomyocardial fibrosis (EMF), a cardiac disease, is prevalent. The latter has been putatively linked to insufficient magnesium intake and excess cerium exposure. Primary teeth were collected from 21 Ugandan and 27 UK children. The crowns and roots of the teeth were separated and the former digested and analysed for several major and trace elements by inductively coupled plasma mass spectrometry (ICP-MS) and atomic emission spectrometry (ICP-AES). In addition, the enamel and dentine of eight UK and seven Ugandan primary teeth were isolated via density separation and analysed as above. The data were assessed using non-parametric statistical tests. The Ugandan teeth contained significantly (P < 0.05) greater concentrations of strontium, barium, cerium, lanthanum, praseodymium and significantly less zinc than the UK teeth. No significant difference in the concentrations of aluminium, calcium, copper, magnesium, lead and uranium were found. Analysis of enamel and dentine demonstrated that the former was enriched with several elements including cerium. It is concluded, that the environment, influences the trace element content of primary teeth and this may be useful for monitoring nutritional status. With respect to a geochemical cause for EMF, there is no positive evidence that EMF in Uganda is associated with reduced magnesium and increased cerium uptake in primary teeth. This does not, however, exclude cerium from playing a role in the aetiology of EMF.

  3. Explosive Volcanic Eruptions from Linear Vents on Earth, Venus and Mars: Comparisons with Circular Vent Eruptions

    NASA Technical Reports Server (NTRS)

    Glaze, Lori S.; Baloga, Stephen M.; Wimert, Jesse

    2010-01-01

    Conditions required to support buoyant convective plumes are investigated for explosive volcanic eruptions from circular and linear vents on Earth, Venus, and Mars. Vent geometry (linear versus circular) plays a significant role in the ability of an explosive eruption to sustain a buoyant plume. On Earth, linear and circular vent eruptions are both capable of driving buoyant plumes to equivalent maximum rise heights, however, linear vent plumes are more sensitive to vent size. For analogous mass eruption rates, linear vent plumes surpass circular vent plumes in entrainment efficiency approximately when L(sub o) > 3r(sub o) owing to the larger entrainment area relative to the control volume. Relative to circular vents, linear vents on Venus favor column collapse and the formation of pyroclastic flows because the range of conditions required to establish and sustain buoyancy is narrow. When buoyancy can be sustained, however, maximum plume heights exceed those from circular vents. For current atmospheric conditions on Mars, linear vent eruptions are capable of injecting volcanic material slightly higher than analogous circular vent eruptions. However, both geometries are more likely to produce pyroclastic fountains, as opposed to convective plumes, owing to the low density atmosphere. Due to the atmospheric density profile and water content on Earth, explosive eruptions enjoy favorable conditions for producing sustained buoyant columns, while pyroclastic flows would be relatively more prevalent on Venus and Mars. These results have implications for the injection and dispersal of particulates into the planetary atmosphere and the ability to interpret the geologic record of planetary volcanism.

  4. The 1999 eruption of Shishaldin Volcano, Alaska: Monitoring a distant eruption

    USGS Publications Warehouse

    Nye, C.J.; Keith, T.E.C.; Eichelberger, J.C.; Miller, T.P.; McNutt, S.R.; Moran, S.; Schneider, D.J.; Dehn, J.; Schaefer, J.R.

    2002-01-01

    Shishaldin Volcano, in the central Aleutian volcanic arc, became seismically restless during the summer of 1998. Increasing unrest was monitored using a newly installed seismic network, weather satellites, and rare local visual observations. The unrest culminated in large eruptions on 19 April and 22-23 April 1999. The opening phase of the 19 April eruption produced a sub-Plinian column that rose to 16 km before rapidly dissipating. About 80 min into the 19 April event we infer that the eruption style transitioned to vigorous Strombolian fountaining. Exceptionally vigorous seismic tremor heralded the 23 April eruption, which produced a large thermal anomaly observable by satellite, but only a modest, 6-km-high plume. There are no ground-based visual observations of this eruption; however we infer that there was renewed, vigorous Strombolian fountaining. Smaller low-level ash-rich plumes were produced through the end of May 1999. The lava that erupted was evolved basalt with about 49% SiO2. Subsequent field investigations have been unable to find a distinction between deposits from each of the two major eruptive episodes.

  5. On the association of erupting magnetic fields with eruptive prominences and coronal mass ejections

    NASA Astrophysics Data System (ADS)

    Rompolt, Bogdan

    1987-09-01

    A number of space and ground-based observations give evidence that the eruptive prominences, coronal mass ejections (CMEs) and associated shocks are generated by a common cause, i.e., the eruption of the magnetic field on the Sun. Some 60% of the observed CMEs are associated with the eruptive prominences. It is believed that in reality a much better correlation should be between these events because of observational limitations and of the effect of partial eruption. Some recent results on the formation and evolution of the quiescent and the active region prominences give an idea on the early phase of eruption of the magnetic field with the prominence plasma frozen in. In the latter phase of eruption the magnetic field lifted high into the corona and is seen (as manifested by the cold plasma frozen in) as a system of huge loops - evidently the result of some reconnections at lower heights. The legs of these erupting loops interact sometimes with the local magnetic field, i.e., it often appears to be an active region. In consequence of this interaction the activation of prominences and generation of flares can take place on some occasions as well as ejection of surges and sprays.

  6. Explosive volcanic eruptions from linear vents on Earth, Venus, and Mars: Comparisons with circular vent eruptions

    NASA Astrophysics Data System (ADS)

    Glaze, Lori S.; Baloga, Stephen M.; Wimert, Jesse

    2011-01-01

    Conditions required to support buoyant convective plumes are investigated for explosive volcanic eruptions from circular and linear vents on Earth, Venus, and Mars. Vent geometry (linear versus circular) plays a significant role in the ability of an explosive eruption to sustain a buoyant plume. On Earth, linear and circular vent eruptions are both capable of driving buoyant plumes to equivalent maximum rise heights; however, linear vent plumes are more sensitive to vent size. For analogous mass eruption rates, linear vent plumes surpass circular vent plumes in entrainment efficiency approximately when Lo ≥ 3ro owing to the larger entrainment area relative to the control volume. Relative to circular vents, linear vents on Venus favor column collapse and the formation of pyroclastic flows because the range of conditions required to establish and sustain buoyancy is narrow. When buoyancy can be sustained, however, maximum plume heights exceed those from circular vents. For current atmospheric conditions on Mars, linear vent eruptions are capable of injecting volcanic material slightly higher than analogous circular vent eruptions. However, both geometries are more likely to produce pyroclastic fountains, as opposed to convective plumes, owing to the low-density atmosphere. Because of the atmospheric density profile and water content on Earth, explosive eruptions enjoy favorable conditions for producing sustained buoyant columns, while pyroclastic flows would be relatively more prevalent on Venus and Mars. These results have implications for the injection and dispersal of particulates into the planetary atmosphere and the ability to interpret the geologic record of planetary volcanism.

  7. An examination of proportional root lengths of the mandibular canine and premolars near the time of eruption.

    PubMed

    Smith, Shelley L; Buschang, Peter H

    2010-12-01

    To make treatments more efficient, orthodontists require a more precise means of estimating tooth eruption. The purpose of this article was to extend the information derived from dental staging techniques by incorporating direct measurements of root lengths for 3 mandibular teeth: the canine and the 2 premolars. The full sample consists of 227 panoramic films from 77 female patients and 229 films from 74 male patients treated at a practice in Texas. A subsample of paired preeruption and posteruption films was examined in greater detail (46 subjects for the canine, 42 for the first premolar, and 46 for the second premolar). Canines will most likely have root length ([root length/total tooth length] × 100) of approximately 70% and premolars will have approximately 65% near the time of alveolar eruption. In addition, the walls of the root canal will probably approach a parallel configuration at the time of eruption. The percentage of root length, along with root canal parallelism, should allow improved prediction of eruption timing. Copyright © 2010 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

  8. CHAIN RECONNECTIONS OBSERVED IN SYMPATHETIC ERUPTIONS

    SciTech Connect

    Joshi, Navin Chandra; Magara, Tetsuya; Schmieder, Brigitte; Aulanier, Guillaume; Guo, Yang E-mail: njoshi98@gmail.com

    2016-04-01

    The nature of various plausible causal links between sympathetic events is still a controversial issue. In this work, we present multiwavelength observations of sympathetic eruptions, associated flares, and coronal mass ejections (CMEs) occurring on 2013 November 17 in two close active regions. Two filaments, i.e., F1 and F2, are observed in between the active regions. Successive magnetic reconnections, caused for different reasons (flux cancellation, shear, and expansion) have been identified during the whole event. The first reconnection occurred during the first eruption via flux cancellation between the sheared arcades overlying filament F2, creating a flux rope and leading to the first double-ribbon solar flare. During this phase, we observed the eruption of overlying arcades and coronal loops, which leads to the first CME. The second reconnection is believed to occur between the expanding flux rope of F2 and the overlying arcades of filament F1. We suggest that this reconnection destabilized the equilibrium of filament F1, which further facilitated its eruption. The third stage of reconnection occurred in the wake of the erupting filament F1 between the legs of the overlying arcades. This may create a flux rope and the second double-ribbon flare and a second CME. The fourth reconnection was between the expanding arcades of the erupting filament F1 and the nearby ambient field, which produced the bi-directional plasma flows both upward and downward. Observations and a nonlinear force-free field extrapolation confirm the possibility of reconnection and the causal link between the magnetic systems.

  9. Nyiragongo Volcano Erupts in the Congo

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Mount Nyiragongo, located in the Democratic Republic of the Congo, erupted today (January 17, 2002), ejecting a large cloud of smoke and ash high into the sky and spewing lava down three sides of the volcano. Mount Nyiragongo is located roughly 10 km (6 miles) north of the town of Goma, near the Congo's border with Rwanda. According to news reports, one river of lava is headed straight toward Goma, where international aid teams are evacuating residents. Already, the lava flows have burned through large swaths of the surrounding jungle and have destroyed dozens of homes. This false-color image was acquired today (January 17) by the Moderate-resolution Imaging Spectroradiometer (MODIS) roughly 5 hours after the eruption began. Notice Mount Nyiragongo's large plume (bright white) can be seen streaming westward in this scene. The plume appears to be higher than the immediately adjacent clouds and so it is colder in temperature, making it easy for MODIS to distinguish the volcanic plume from the clouds by using image bands sensitive to thermal radiation. Images of the eruption using other band combinations are located on the MODIS Rapid Response System. Nyiragongo eruptions are extremely hazardous because the lava tends to be very fluid and travels down the slopes of the volcano quickly. Eruptions can be large and spectacular, and flows can reach up to 10s of kilometers from the volcano very quickly. Also, biomass burned from Nyriagongo, and nearby Mount Nyamuragira, eruptions tends to create clouds of smoke that adversely affect the Mountain Gorillas living in the adjacent mountain chain. Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC

  10. Particle aggregation in volcanic eruption columns

    NASA Astrophysics Data System (ADS)

    Veitch, Graham; Woods, Andrew W.

    2001-11-01

    We develop a model to describe the formation of aggregates in a volcanic eruption column. The model combines a description of the rate of collision and sticking of particles with a model of the vertical transport in the eruption column. We thereby determine the evolution of the grain size distribution as a function of height in the eruption column. We consider aggregates in which liquid water provides the binding agent. For sufficiently large eruption columns we find that this limits the vertical extent of the zone where aggregates may form since near the source, all water is in the vapor form, while in the upper part of the column the mixture becomes very cold and freezes. However, in many cases, we find that the particles spend sufficient time in the central region, where the water is in the liquid form, that a substantial amount of aggregation occurs. Furthermore, we predict that owing to the reduction in the binding efficiency of water as particle size increases [Gilbert and Lane, 1994], there is a relatively narrow size distribution of aggregates at the plume top. We also model the airfall deposits associated with this aggregate-rich distribution of particles which is injected to the top of the eruption column. We show that the relatively narrow size distribution of particles at the top of the column, coupled with the gravitational settling and transport by ambient winds, may lead to enhanced deposition close to the source and in some cases secondary thickening of the deposit. The relatively near-source deposition of fine ash in these deposits is associated with the fallout of aggregates. As a simple application, we show that the present dynamical aggregation model is consistent with the secondary thickening of the deposit from the May 18, 1980, eruption of Mount St. Helens.

  11. Modeling the Evolution of Effusive Silicic Eruptions

    NASA Astrophysics Data System (ADS)

    Anderson, K. R.; Segall, P.

    2009-12-01

    We have developed a numerical model for the evolution of an effusive silicic volcanic eruption that couples a deflating magma chamber with flow of magma through a cylindrical conduit to the surface. At shallow depths the magma crystallizes into a solid plug which slips relative to the conduit wall according to a rate-dependent friction law. Magma properties in the chamber and conduit, as well as frictional sliding behavior, are coupled to deformation of the surrounding rock. The model allows us to fully couple time-dependent geodetic data (such as GPS time series) and dome-growth (extruded volume as a function of time) to provide better constraints on subsurface magma physics than possible using individual data sets in isolation. Rather than estimating simple 'best-fitting' parameters, we use a Markov-Chain Monte Carlo (MCMC) technique to estimate full posterior probabilities for all estimated parameters, providing valuable information on the ability of the data to constrain physical parameters of interest. We apply the model to the 2004-2008 eruption of Mount St. Helens, Washington, and estimate initial chamber volume, overpressure, and friction parameters for the solid plug, among other parameters. Earlier versions of our model considered only the evolution of the eruption, but we have extended the approach to consider both pre-eruptive and post-eruptive periods as well. By examining the onset, evolution, and cessation of a single eruption with a single physically realistic model we are able to better constrain key model parameters. We believe that models of this type, which couple multiple datasets and estimate full posterior probabilities for realistic subsurface magma physics (rather than estimating purely kinematic best-fitting pressure changes), will become increasingly important as geophysical datasets continue to improve and computation costs continue to fall.

  12. Materials for Paediatric Dentistry. Part 1: Background to the Treatment of Carious Primary Teeth.

    PubMed

    Jenkins, Natalie

    2015-12-01

    Dental caries is a disease that affects many people, including children, and presents numerous challenges to healthcare providers. As clinicians it is important that we consider the advantages and disadvantages of treating carious primary teeth, and make an informed decision about when it is appropriate or not. This paper describes the background to the treatment of carious primary teeth, looking at the differences between primary and permanent teeth, and the relevance of this. It also suggests points to consider when looking at restoration survival studies, as the ability to appraise the literature critically is important for us all in this 'evidence-based' age. CPD/Clinical Relevance: Our early life experiences have the ability to shape our future attitudes and behaviour. Children with carious teeth require careful management so that pain and suffering is minimized, and positive attitudes towards dentistry are fostered.

  13. New bacterial compositions in root-filled teeth with periradicular lesions.

    PubMed

    Schirrmeister, Jörg F; Liebenow, Anna-Lisa; Pelz, Klaus; Wittmer, Annette; Serr, Annerose; Hellwig, Elmar; Al-Ahmad, Ali

    2009-02-01

    The aim of this study was to isolate and detect microorganisms of root-filled teeth associated with periradicular lesions. Specimens were sampled from patients undergoing root canal retreatment. The bacteria were characterized by morphologic and biochemical analysis and by 16S rRNA gene sequencing. Microorganisms were detected in 10 of 18 teeth. The majority of positive samples revealed a mixed culture of 2-8 species. In 2 teeth Enterococcus faecalis was the only detected species. For the first time Vagococcus fluvialis was detected in root canals. Solobacterium moorei and Fusobacterium nucleatum were the most prevalent species. Presence of F. nucleatum was associated with the presence of S. moorei in 5 of 7 cases. In all teeth with Parvimonas micra and Dialister invisus, F. nucleatum and S. moorei were found. Moreover, members of additional different genera were detected delivering bacterial compositions that have been not described yet.

  14. Laser and LED external teeth-bleaching

    NASA Astrophysics Data System (ADS)

    Zanin, Fatima A.; Brugnera, Aldo, Jr.; Marchesan, Melissa A.; Pecora, Jesus D.

    2004-09-01

    Teeth-bleaching is an initial phase in the reproduction of an aesthetic smile; thus, it is very important that the dentist knows how to diagnose the causes of color changes and indicate whitening before proposing dental treatment. Technological advances in teeth-whitening lead to the development of new techniques, improving comfort, security and decreasing time of execution: argon laser, diode Laser, LED whitening, xenon light whitening. The clearing agent used in all techniques, including home whitening, is hydrogen peroxide (H2O2) in different concentrations. In this study, the authors describe mechanisms of gel activation, the use of Laser and LED"s for teeth-bleaching, the importance of diagnosis and the comfort of the patient in in-office teeth-bleaching techniques.

  15. Laser and LED external teeth-bleaching

    NASA Astrophysics Data System (ADS)

    Zanin, Fatima; Brugnera, Aldo, Jr.; Marchesan, Melissa A.; Pecora, Jesus D.

    2004-05-01

    Teeth-bleaching is an initial phase in the reproduction of an aesthetic smile; thus, it is very important that the dentist knows how to diagnose the causes of color changes and indicate whitening before proposing dental treatment. Technological advances in teeth-whitening lead to the development of new techniques, improving comfort, security and decreasing time of execution: argon laser, diode laser, LED whitening, xenon light whitening. The clearing agent used in all techniques, including home whitening, is hydrogen peroxide (H2O2) in different concentrations. In this study, the authors describe mechanisms of gel activation, the use of Laser and LED's for teeth-bleaching, the importance of diagnosis and the comfort of the patient in in-office teeth-bleaching techniques.

  16. Stability of volcanic conduits during explosive eruptions

    NASA Astrophysics Data System (ADS)

    Aravena, Álvaro; de'Michieli Vitturi, Mattia; Cioni, Raffaello; Neri, Augusto

    2017-06-01

    Geological evidences of volcanic conduit widening are common in most pyroclastic deposits (e.g. presence of lithic fragments from different depths), suggesting a continuous modification of the conduit geometry during volcanic eruptions. However, the controlling factors of the mechanisms driving conduit enlargement (e.g. erosion, local collapse) are still partially unclear, as well as the influence of conduit geometry on the eruptive dynamics. Although numerical models have been systematically employed to study volcanic conduits, their mechanical stability and the eruptive dynamics related to non-cylindrical conduits have been poorly addressed. We present here a 1D steady-state model which includes the main processes experimented by ascending magmas (i.e. crystallization, rheological changes, fragmentation, drag forces, outgassing and degassing), and the application of two mechanical stability criteria (Mohr-Coulomb and Mogi-Coulomb), in order to study the collapse conditions of volcanic conduits during a representative explosive rhyolitic eruption. It emerges that mechanical stability of volcanic conduits is mainly controlled by its radial dimension, and a minimum radius for reaching stable conditions can be computed, as a function of water content and inlet overpressure. Additionally, for a set of input parameters thought typical of explosive rhyolitic volcanism, we estimated a minimum magma flux for developing a mechanically stable conduit ( 7 • 107 - 3 • 108 kg/s). Results are consistent with the unsteady character usually observed in sub-Plinian eruptions, opposite to mainly stationary Plinian eruptions, commonly characterized by higher magma discharge rates. We suggest that cylindrical conduits represent a mechanically stable configuration only for large radii. Because the instability conditions are not uniform along the conduit, the widening processes probably lead to conduit geometries with depth-varying width. Consequently, as our model is able to

  17. Multiple Eruptive Keratoacanthomas Arising in a Tattoo

    PubMed Central

    Vitiello, Magalys; Echeverria, Begoña; Romanelli, Paolo; Abuchar, Adriana

    2010-01-01

    Keratoacanthomas are rapidly growing, keratinizing, epithelial neoplasms that tend to spontaneously involute and are rarely multiple or eruptive. There is still disagreement on whether or not this condition is a malignancy or a benign epidermal neoplasm; nevertheless, its appearance on tattoos has been reported in rare instances. When waiting for spontaneous involution is not an option, surgery is the preferred treatment. Other therapeutic modalities used for the treatment of this condition include radiotherapy; cryotherapy; laser therapy; and multiple intralesional, topical, and systemic agents. The authors report a patient who developed multiple, eruptive keratoacanthomas in the red ink portions of a tattoo and was successfully treated with acitretin. PMID:20725558

  18. Global science: the eruption of Krakatau.

    PubMed

    Dörries, Matthias

    2003-01-01

    The eruption of the volcano Krakatau in the Netherlands East Indies (Indonesia) in 1883 had worldwide impact. This was perceived in the three quite different types of global propagation that occurred after the eruption: a rapid pressure wave, noticeable only to measuring instruments, followed a few hours later by the spread of the news of the event, succeeded by a slowly expanding optical phenomenon that lasted for a couple of years. Krakatau was the first natural catastrophe of global magnitude that was almost immediately recognized as such throughout the world, largely thanks to the recently installed worldwide telegraphic network.

  19. Increased number of teeth predict acquisition of mutans streptococci in infants

    PubMed Central

    Nelson, Suchitra; Albert, Jeffery Marvin; Soderling, Eva; Malik, Anchal; Curtan, Shelley; Geng, Cuiyu; Milgrom, Peter

    2014-01-01

    This longitudinal study of 194 very low birth weight (VLBW) and 184 normal birth weight (NBW) infants, hypothesized that the causal pathway between birth group (VLBW, NBW) and mutans streptococci (MS) acquisition (presence) at 18-20 months is mediated by biological, behavioral, and caregiver MS levels. Biological (number of teeth at 8 and 18-20 months, enamel hypoplasia) and behavioral (brushing/cleaning, sweet snacks, breast feeding, dental access) factors were assessed using dental exams and caregiver questionnaire responses at 8 and 18-20 months. Infant MS acquisition and caregiver levels were assessed from saliva and plaque samples collected at 8 and 18-20 months. Structural equations model evaluated the causal pathway with latent variables for biology and behavior. MS presence was similar between birth groups at 18-20 months (VLBW: 40%; NBW: 49%), but significantly higher for NBW at 8 months. Increased number of teeth at 8 and 18-20 months was associated with biological risk. Infants whose caregivers had a one point higher score on MS had a significantly 1.5 higher odds of MS presence. Caregiver behavior was not associated with MS presence. Early Intervention efforts should focus on delaying initial acquisition and improving caregiver awareness of taking care of erupting primary teeth. PMID:25183438

  20. Genome-wide association study of primary tooth eruption identifies pleiotropic loci associated with height and craniofacial distances.

    PubMed

    Fatemifar, Ghazaleh; Hoggart, Clive J; Paternoster, Lavinia; Kemp, John P; Prokopenko, Inga; Horikoshi, Momoko; Wright, Victoria J; Tobias, Jon H; Richmond, Stephen; Zhurov, Alexei I; Toma, Arshed M; Pouta, Anneli; Taanila, Anja; Sipila, Kirsi; Lähdesmäki, Raija; Pillas, Demetris; Geller, Frank; Feenstra, Bjarke; Melbye, Mads; Nohr, Ellen A; Ring, Susan M; St Pourcain, Beate; Timpson, Nicholas J; Davey Smith, George; Jarvelin, Marjo-Riitta; Evans, David M

    2013-09-15

    Twin and family studies indicate that the timing of primary tooth eruption is highly heritable, with estimates typically exceeding 80%. To identify variants involved in primary tooth eruption, we performed a population-based genome-wide association study of 'age at first tooth' and 'number of teeth' using 5998 and 6609 individuals, respectively, from the Avon Longitudinal Study of Parents and Children (ALSPAC) and 5403 individuals from the 1966 Northern Finland Birth Cohort (NFBC1966). We tested 2 446 724 SNPs imputed in both studies. Analyses were controlled for the effect of gestational age, sex and age of measurement. Results from the two studies were combined using fixed effects inverse variance meta-analysis. We identified a total of 15 independent loci, with 10 loci reaching genome-wide significance (P < 5 × 10(-8)) for 'age at first tooth' and 11 loci for 'number of teeth'. Together, these associations explain 6.06% of the variation in 'age of first tooth' and 4.76% of the variation in 'number of teeth'. The identified loci included eight previously unidentified loci, some containing genes known to play a role in tooth and other developmental pathways, including an SNP in the protein-coding region of BMP4 (rs17563, P = 9.080 × 10(-17)). Three of these loci, containing the genes HMGA2, AJUBA and ADK, also showed evidence of association with craniofacial distances, particularly those indexing facial width. Our results suggest that the genome-wide association approach is a powerful strategy for detecting variants involved in tooth eruption, and potentially craniofacial growth and more generally organ development.

  1. Observation of Etna explosive eruptions yield an enhancement of the models of eruption column

    NASA Astrophysics Data System (ADS)

    Coltelli, M.; Scollo, S.

    2003-04-01

    Big explosive volcanic eruptions generate large quantities of fine-grained volcanic particles (tephra) injecting them into atmosphere by vigorous convective plumes (eruption column). The fallout of tephra causes severe respiratory problems, interferes with air and ground traffic, and produce large damages to telecommunication facilities, roads, houses, forests and cultivated lands. Moreover the ash cloud, transported by atmosferic winds, can drift over great distance causing disruption to air traffic. The spreading and dispersal of volcanic plumes within the atmosphere results from interaction with atmosferic motions and stratification. Ground accumulation of tephra forms widespread pyroclastic fall deposits, their dispersion, thickness and grain-size allow us to calculate volume, magnitude and some physical parameters of the eruption, as mass eruption rate, using simple formulas derived by turbulent convective plume theory in a stratified atmosphere. Etna is a basaltic volcano characterized by frequent explosive eruptions usually described as Strombolian or fire fountains. In spite of this opinion several eruptive events formed sustained eruption columns that rose up to the lower stratosphere (10-15 km a.s.l.). Mapping and sampling of the fallout deposits carried out in a few hours after the events allowed us to collect data for drawing spatial dispersion (isomass map) down to a few grams per squared meter and for plotting grain-size distribution of samples with no reworking. These data demonstrate that dispersal characteristics of Etna's fallout deposits fit well the models that describe sustained columns of Plinian eruptions. So Etna could be used to test present and future tephra fallout models to evaluate their effectiveness such us, for example, the 22 July 1998 explosive event at the Voragine summit crater. We have used fallout models solving advection-diffusion equations for particles moving in a turbulent atmosphere and we can demonstrate that this king of

  2. The frequency of explosive volcanic eruptions in Southeast Asia.

    PubMed

    Whelley, Patrick L; Newhall, Christopher G; Bradley, Kyle E

    There are ~750 active and potentially active volcanoes in Southeast Asia. Ash from eruptions of volcanic explosivity index 3 (VEI 3) and smaller pose mostly local hazards while eruptions of VEI ≥ 4 could disrupt trade, travel, and daily life in large parts of the region. We classify Southeast Asian volcanoes into five groups, using their morphology and, where known, their eruptive history and degassing style. Because the eruptive histories of most volcanoes in Southeast Asia are poorly constrained, we assume that volcanoes with similar morphologies have had similar eruption histories. Eruption histories of well-studied examples of each morphologic class serve as proxy histories for understudied volcanoes in the class. From known and proxy eruptive histories, we estimate that decadal probabilities of VEI 4-8 eruptions in Southeast Asia are nearly 1.0, ~0.6, ~0.15, ~0.012, and ~0.001, respectively.

  3. Straight, white teeth as a social prerogative.

    PubMed

    Khalid, Abeer; Quiñonez, Carlos

    2015-06-01

    A distinguishing feature of North American society is preoccupation with self-image, as seen in the ritualistic nature of bodily practices aimed at constantly improving the body. Nowhere is this more apparent than in the prevailing fixation with straight, white teeth. While there is an ever-expanding literature on the sociology of body, very little has been written on teeth in this context. Using literature from anthropology, biology, dentistry, sociology and social psychology, this study attempts to answer: (1) Why have straight, white teeth become a beauty ideal in North American society? (2) What is the basis for this ideal? (3) How is this ideal propagated? It demonstrates that dental aesthetic tendencies are biologically, culturally and socially patterned. Concepts from the works of Pierre Bourdieu and Michel Foucault are used to illustrate how straight, white teeth contribute towards reinforcing class differences and how society exercises a disciplinary power on individuals through this ideal. It is concluded that modified teeth are linked to self and identity that are rooted in social structure. Moreover, teeth demonstrate the ways in which class differences are embodied and projected as symbols of social advantage or disadvantage. Implications on professional, public health, sociological and political levels are considered. © 2015 Foundation for the Sociology of Health & Illness.

  4. Reduction of randomness in seismic noise as a short-term precursor to a volcanic eruption

    PubMed Central

    Glynn, C. C.; Konstantinou, K. I.

    2016-01-01

    Ambient seismic noise is characterized by randomness incurred by the random position and strength of the noise sources as well as the heterogeneous properties of the medium through which it propagates. Here we use ambient noise data recorded prior to the 1996 Gjálp eruption in Iceland in order to show that a reduction of noise randomness can be a clear short-term precursor to volcanic activity. The eruption was preceded on 29 September 1996 by a Mw ~5.6 earthquake that occurred in the caldera rim of the Bárdarbunga volcano. A significant reduction of randomness started occurring 8 days before the earthquake and 10 days before the onset of the eruption. This reduction was observed even at stations more than 100 km away from the eruption site. Randomness increased to its previous levels 160 minutes after the Bárdarbunga earthquake, during which time aftershocks migrated from the Bárdarbunga caldera to a site near the Gjálp eruption fissure. We attribute this precursory reduction of randomness to the lack of higher frequencies (>1 Hz) in the noise wavefield caused by high absorption losses as hot magma ascended in the upper crust. PMID:27883050

  5. Active Eruptions in the NE Lau Basin

    NASA Astrophysics Data System (ADS)

    Resing, J. A.; Embley, R. W.

    2009-12-01

    NE Lau Response Team: K Rubin, E Baker, J Lupton, M Lilley, T Shank, S Merle, R Dziak, T Collasius (Jason 2 Expedition Leader), N Buck, T Baumberger, D Butterfield, D Clague, D Conlin, J Cowen, R Davis, L Evans, J Huber, M Keith, N Keller, P Michael, E Podowski, A-L Reysenbach, K Roe, H Thomas, S Walker. During a May 2009 cruise to W Mata volcano in the NE Lau Basin, we made the first observations of an active eruption on the deep-sea floor. The cruise was organized after volcanic activity was detected at two sites (W Mata volcano and NE Lau Spreading Center, NELSC) during a Nov. 2008 NOAA-PMEL expedition. At that time, both sites had elevated H2 concentrations and volcaniclastic shards in the hydrothermal plumes. Moored hydrophone data since Jan 2009 indicate that the activity at W Mata has been continuous between these expeditions. Results of our cruise and other work suggest that the NE Lau Basin hosts an unusually high level of magmatic activity, making it an ideal location to study the effects of magmatic processes on hydrothermal activity and associated ecosystems. W Mata was visited with 5 ROV Jason 2 dives and 2 dives with the MBARI autonomous mapping vehicle in May 2009. It was actively erupting at the 1200 m deep summit during each, so a hydrophone was deployed locally to collect acoustic data. Ship and shore-based analysis of HD video, molten lava, rocks, sediments, hot spring waters, and micro- and macro biological specimens collected by Jason 2 have provided a wealth of data. The eruption itself was characterized by extrusion of red, molten lava, extensive degassing, formation of large magma bubbles, explosive pyroclast ejection, and the active extrusion of pillow lavas. The erupting magmas are boninite, a relatively rare magma type found only at convergent margins. The hydrothermal fluids are generally acidic and all diffuse fluids collected were microbially active, even those at pH <3. W Mata was host to shrimp similar to those found at several other

  6. Filament Eruptions, Jets, and Space Weather

    NASA Technical Reports Server (NTRS)

    Moore, Ronald; Sterling, Alphonse; Robe, Nick; Falconer, David; Cirtain, Jonathan

    2013-01-01

    Previously, from chromospheric H alpha and coronal X-ray movies of the Sun's polar coronal holes, it was found that nearly all coronal jets (greater than 90%) are one or the other of two roughly equally common different kinds, different in how they erupt: standard jets and blowout jets (Yamauchi et al 2004, Apl, 605, 5ll: Moore et all 2010, Apj, 720, 757). Here, from inspection of SDO/AIA He II 304 A movies of 54 polar x-ray jets observed in Hinode/XRT movies, we report, as Moore et al (2010) anticipated, that (1) most standard x-ray jets (greater than 80%) show no ejected plasma that is cool enough (T is less than or approximately 10(exp 5K) to be seen in the He II 304 A movies; (2) nearly all blownout X-ray jets (greater than 90%) show obvious ejection of such cool plasma; (3) whereas when cool plasma is ejected in standard X-ray jets, it shows no lateral expansion, the cool plasma ejected in blowout X-ray jets shows strong lateral expansion; and (4) in many blowout X-ray jets, the cool plasma ejection displays the erupting-magnetic-rope form of clasic filament eruptions and is thereby seen to be a miniature filament eruption. The XRT movies also showed most blowout X-ray jets to be larger and brighter, and hence to apparently have more energy, than most standard X-ray jets. These observations (1) confirm the dichotomy of coronal jets, (2) agree with the Shibata model for standard jets, and (3) support the conclusion of Moore et al (2010) that in blowout jets the magnetic-arch base of the jet erupts in the manner of the much larger magnetic arcades in which the core field, the field rooted along the arcade's polarity inversion line, is sheared and twisted (sigmoid), often carries a cool-plasma filament, and erupts to blowout the arcade, producing a CME. From Hinode/SOT Ca II movies of the polar limb, Sterling et al (2010, ApJ, 714, L1) found that chromospheric Type-II spicules show a dichotomy of eruption dynamics similar to that found here for the cool

  7. Asia-Pacific Region Global Earthquake and Volcanic Eruption Risk Management (G-EVER) project and a next-generation real-time volcano hazard assessment system

    NASA Astrophysics Data System (ADS)

    Takarada, S.

    2012-12-01

    vent position, volume, eruption rate, wind directions and topography. Therefore, numerical simulations with controlled parameters are needed for more precise volcanic eruption predictions. The use of the next-generation system should enable the visualization of past volcanic eruptions datasets such as distributions, eruption volumes and eruption rates, on maps and diagrams using timeline and GIS technology. Similar volcanic eruptions scenarios should be easily searchable from the eruption database. Using the volcano hazard assessment system, prediction of the time and area that would be affected by volcanic eruptions at any locations near the volcano should be possible, using numerical simulations. The system should estimate volcanic hazard risks by overlaying the distributions of volcanic deposits on major roads, houses and evacuation areas using a GIS enabled systems. Probabilistic volcanic hazards maps in active volcano sites should be made based on numerous numerical simulations. The next-generation real-time hazard assessment system would be implemented with user-friendly interface, making the risk assessment system easily usable and accessible online.

  8. Effects of loss of occlusal contact on the expression of matrix metalloproteinase-2, membrane type 1-MMP, tissue inhibitor of the MMP-2, eruption rate, organization and resistance of collagen fibers of the rat incisor periodontal ligament.

    PubMed

    Omar, N F; Gomes, J R; Neves, J S; Novaes, P D

    2018-02-01

    This study investigated the effect of occlusal contact loss (induced by tooth shortening), on matrix metalloproteinase (MMP)-2, membrane type 1-MMP (MT1-MMP) and tissue inhibitor of the MMP-2 (TIMP-2) expressions in the periodontal ligament of the rat incisor, as well as eruption rate, resistance and collagen organization. Male Wistar rats were distributed into a control group, denominated normofunctional group, whose lower teeth underwent a normal eruption process; and a hypofunctional group, whose lower left incisor teeth were shortened every 2 days during 14 days. Parameters were evaluated on the first, seventh and 14th days and the eruption rate was determined according to the size of the incisor during the eruption process. MMP-2 activity was determined by zymography and the expressions of the MT1-MMP and TIMP-2 proteins were quantitated by western blot. Collagen protein organization, as indicated by the birefringence of the periodontal ligament, was analyzed under polarized light and the periodontal ligament's resistance was determined from the load necessary to inject the incisor into its alveolar space, before extraction. Loss of occlusal contact, in rats submitted to hypofunctional eruption, increased MMP-2 activity and eruption rate, but decreased MT1-MMP and TIMP-2 expression and disrupted collagen organization in the periodontal ligament, consequently reducing periodontal ligament resistance. We conclude that, after incisor eruption, occlusal contact may be an important factor for regulating the remodeling and the physiological resistance of the periodontal ligament against the continuous eruption process observed in rat incisors. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  9. Burst conditions of explosive volcanic eruptions recorded on microbarographs

    USGS Publications Warehouse

    Morrissey, M.M.; Chouet, B.A.

    1997-01-01

    Explosive volcanic eruptions generate pressure disturbances in the atmosphere that propagate away either as acoustic or as shock waves, depending on the explosivity of the eruption. Both types of waves are recorded on microbarographs as 1- to 0.1-hertz N-shaped signals followed by a longer period coda. These waveforms can be used to estimate burst pressures end gas concentrations in explosive volcanic eruptions and provide estimates of eruption magnitudes.

  10. Holocene eruptive activity of El Chichon volcano, Chiapas, Mexico

    NASA Astrophysics Data System (ADS)

    Tilling, R. I.; Rubin, M.; Sigurdsson, H.; Carey, S.; Duffield, W. A.; Rose, W. I.

    1984-05-01

    Geologic and radiometric-age data indicate that El Chichon was frequently and violently active during the Holocene, including eruptive episodes about 600, 1250, and 1700 years ago and several undated, older eruptions. These episodes, involving explosive eruptions of sulfur-rich magma and associated domegrowth processes, were apparently separated by intervals of approximately 350 to 650 years. Some of El Chichon's eruptions may correlate with unusual atmospheric phenomena around A.D. 1300 and possibly A.D. 623.

  11. Sulphur-rich volcanic eruptions and stratospheric aerosols

    NASA Technical Reports Server (NTRS)

    Rampino, M. R.; Self, S.

    1984-01-01

    Data from direct measurements of stratospheric optical depth, Greenland ice-core acidity, and volcanological studies are compared, and it is shown that relatively small but sulfur-rich volcanic eruptions can have atmospheric effects equal to or even greater than much larger sulfur-poor eruptions. These small eruptions are probably the most frequent cause of increased stratospheric aerosols. The possible sources of the excess sulfur released in these eruptions are discussed.

  12. Differential diagnosis of primary failure of eruption (PFE) with and without evidence of pathogenic mutations in the PTHR1 gene.

    PubMed

    Pilz, P; Meyer-Marcotty, P; Eigenthaler, M; Roth, H; Weber, B H F; Stellzig-Eisenhauer, A

    2014-05-01

    Primary failure of eruption (PFE) may be associated with pathogenic mutations in the PTHR1 gene. It has numerous manifestations and is characterized by severe posterior open bite. However, there are also phenotypically similar types of eruption anomalies not associated with a known pathogenic PTHR1 mutation. The purpose of this study was to evaluate whether a distinction can be made between PTHR1-mutation carriers and noncarriers based on clinical and radiological findings. A total of 36 patients with suspected PFE diagnoses were included and analyzed in accordance with specific clinical and radiographic criteria. In addition, all patients underwent Sanger DNA sequencing analysis of all coding sequences (and the immediate flanking intronic sequences) of the PTHR1 gene. Of these patients, 23 exhibited a heterozygous pathogenic mutation in the PTHR1 gene (PTHR1-mutation carriers), while molecular genetic analysis revealed nosequence alteration in the other 13 patients (non-PTHR1-mutation carriers). Relevant family histories were obtained from 5 patients in the carrier group; hence, this group included a total of 13 familial and 10 simplex cases. The group of noncarriers revealed no relevant family histories. All patients in the carrier group met six of the clinical and radiographic criteria explored in this study: (1) posterior teeth more often affected; (2) eruption disturbance of an anterior tooth in association with additional posterior-teeth involvement; (3) affected teeth resorbing the alveolar bone located coronal to them; (4) involvement of both deciduous and permanent teeth; (5) impaired vertical alveolar-process growth; and (6) severe subsequent finding of posterior open bite. None of the analyzed criteria were, by contrast, met by all patients in the noncarrier group. All patients in the carrier group could be assigned to one of three classifications indicating the extent of eruption disturbance, whereas 4 of the 13 noncarriers presented none of these three

  13. First fossil evidence for the advance of replacement teeth coupled with life history evolution along an anagenetic mammalian lineage.

    PubMed

    Jordana, Xavier; Marín-Moratalla, Nekane; Moncunill-Solé, Blanca; Bover, Pere; Alcover, Josep Antoni; Köhler, Meike

    2013-01-01

    In mammals that grow up more slowly and live longer, replacement teeth tend to appear earlier in sequence than in fast growing mammals. This trend, known as 'Schultz's Rule', is a useful tool for inferring life histories of fossil taxa. Deviations from this rule, however, suggest that in addition to the pace of life history, ecological factors may also drive dental ontogeny. Myotragus balearicus is an extinct insular caprine that has been proved to be an excellent test case to correlate morphological traits with life history. Here we show that Myotragus balearicus exhibits a slow signature of dental eruption sequence that is in agreement with the exceptionally slow life history of this species, thus conforming to 'Schultz's Rule'. However, our results also show an acceleration of the absolute pace of development of the permanent incisors in relation to that of the posterior teeth. The rodent-like incisors of Myotragus balearicus erupted early not only in relative but also in absolute terms (chronological age), suggesting that feeding characteristics also plays an important role in dental ontogeny. This is in agreement with ecological hypotheses based on primates. Our study documents a decoupling of the pace of development of teeth in mammals that is triggered by different selection pressures on dental ontogeny. Moreover, we show that Myotragus kopperi from the early Pleistocene (a direct ancestor of the late Pleistocene-Holocene M. balearicus) follows the pattern of first incisor replacement known in living bovids. Hence, the advance in the eruption sequence of the first incisors occurs along the Myotragus evolutionary lineage over a period of about 2.5 Myr. To our knowledge, this is the first fossil evidence of an advance of the emergence of the permanent first incisor along an anagenetic mammalian lineage.

  14. First Fossil Evidence for the Advance of Replacement Teeth Coupled with Life History Evolution along an Anagenetic Mammalian Lineage

    PubMed Central

    Jordana, Xavier; Marín-Moratalla, Nekane; Moncunill-Solé, Blanca; Bover, Pere; Alcover, Josep Antoni; Köhler, Meike

    2013-01-01

    In mammals that grow up more slowly and live longer, replacement teeth tend to appear earlier in sequence than in fast growing mammals. This trend, known as ‘Schultz's Rule’, is a useful tool for inferring life histories of fossil taxa. Deviations from this rule, however, suggest that in addition to the pace of life history, ecological factors may also drive dental ontogeny. Myotragus balearicus is an extinct insular caprine that has been proved to be an excellent test case to correlate morphological traits with life history. Here we show that Myotragus balearicus exhibits a slow signature of dental eruption sequence that is in agreement with the exceptionally slow life history of this species, thus conforming to ‘Schultz's Rule’. However, our results also show an acceleration of the absolute pace of development of the permanent incisors in relation to that of the posterior teeth. The rodent-like incisors of Myotragus balearicus erupted early not only in relative but also in absolute terms (chronological age), suggesting that feeding characteristics also plays an important role in dental ontogeny. This is in agreement with ecological hypotheses based on primates. Our study documents a decoupling of the pace of development of teeth in mammals that is triggered by different selection pressures on dental ontogeny. Moreover, we show that Myotragus kopperi from the early Pleistocene (a direct ancestor of the late Pleistocene-Holocene M. balearicus) follows the pattern of first incisor replacement known in living bovids. Hence, the advance in the eruption sequence of the first incisors occurs along the Myotragus evolutionary lineage over a period of about 2.5 Myr. To our knowledge, this is the first fossil evidence of an advance of the emergence of the permanent first incisor along an anagenetic mammalian lineage. PMID:23936247

  15. Tidally modulated eruptions on Enceladus: Cassini ISS observations and models

    SciTech Connect

    Nimmo, Francis; Porco, Carolyn; Mitchell, Colin, E-mail: carolyn@ciclops.org

    2014-09-01

    We use images acquired by the Cassini Imaging Science Subsystem (ISS) to investigate the temporal variation of the brightness and height of the south polar plume of Enceladus. The plume's brightness peaks around the moon's apoapse, but with no systematic variation in scale height with either plume brightness or Enceladus' orbital position. We compare our results, both alone and supplemented with Cassini near-infrared observations, with predictions obtained from models in which tidal stresses are the principal control of the eruptive behavior. There are three main ways of explaining the observations: (1) the activity is controlled by right-lateral strike slip motion;more » (2) the activity is driven by eccentricity tides with an apparent time delay of about 5 hr; (3) the activity is driven by eccentricity tides plus a 1:1 physical libration with an amplitude of about 0.°8 (3.5 km). The second hypothesis might imply either a delayed eruptive response, or a dissipative, viscoelastic interior. The third hypothesis requires a libration amplitude an order of magnitude larger than predicted for a solid Enceladus. While we cannot currently exclude any of these hypotheses, the third, which is plausible for an Enceladus with a subsurface ocean, is testable by using repeat imaging of the moon's surface. A dissipative interior suggests that a regional background heat source should be detectable. The lack of a systematic variation in plume scale height, despite the large variations in plume brightness, is plausibly the result of supersonic flow; the details of the eruption process are yet to be understood.« less

  16. Relative magnetic helicity as a diagnostic of solar eruptivity

    NASA Astrophysics Data System (ADS)

    Pariat, E.; Leake, J. E.; Valori, G.; Linton, M. G.; Zuccarello, F. P.; Dalmasse, K.

    2017-05-01

    Context. The discovery of clear criteria that can deterministically describe the eruptive state of a solar active region would lead to major improvements on space weather predictions. Aims: Using series of numerical simulations of the emergence of a magnetic flux rope in a magnetized coronal, leading either to eruptions or to stable configurations, we test several global scalar quantities for the ability to discriminate between the eruptive and the non-eruptive simulations. Methods: From the magnetic field generated by the three-dimensional magnetohydrodynamical simulations, we compute and analyze the evolution of the magnetic flux, of the magnetic energy and its decomposition into potential and free energies, and of the relative magnetic helicity and its decomposition. Results: Unlike the magnetic flux and magnetic energies, magnetic helicities are able to markedly distinguish the eruptive from the non-eruptive simulations. We find that the ratio of the magnetic helicity of the current-carrying magnetic field to the total relative helicity presents the highest values for the eruptive simulations, in the pre-eruptive phase only. We observe that the eruptive simulations do not possess the highest value of total magnetic helicity. Conclusions: In the framework of our numerical study, the magnetic energies and the total relative helicity do not correspond to good eruptivity proxies. Our study highlights that the ratio of magnetic helicities diagnoses very clearly the eruptive potential of our parametric simulations. Our study shows that magnetic-helicity-based quantities may be very efficient for the prediction of solar eruptions.

  17. A volcano bursting at the seams: Inflation, faulting, and eruption at Sierra Negra volcano, Galápagos

    USGS Publications Warehouse

    Chadwick, William W.; Geist, Dennis J.; Jonsson, Sigurjon; Poland, Michael P.; Johnson, Daniel J.; Meertens, Charles M.

    2006-01-01

    The results of geodetic monitoring since 2002 at Sierra Negra volcano in the Galápagos Islands show that the filling and pressurization of an ∼2-km-deep sill eventually led to an eruption that began on 22 October 2005. Continuous global positioning system (CGPS) monitoring measured >2 m of accelerating inflation leading up to the eruption and contributed to nearly 5 m of total uplift since 1992, the l