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Sample records for teeth position eruption

  1. Equine dental disease part 2: a long-term study of 400 cases: disorders of development and eruption and variations in position of the cheek teeth.

    PubMed

    Dixon, P M; Tremaine, W H; Pickles, K; Kuhns, L; Hawe, C; McCann, J; McGorum, B C; Railton, D I; Brammer, S

    1999-11-01

    Of 400 referred horses with dental disorders, 349 cases suffered from primary disorders of their cheek teeth, ninety of these from disorders of development or eruption, or displacements. These included 20 cases with rostral maxillary and caudal mandibular cheek teeth overgrowths, 16 with diastemata, 15 with grossly enlarged mandibular 'eruption cysts', 4 with grossly enlarged maxillary cheek teeth 'eruption cysts', 10 cases with supernumerary cheek teeth and 23 cases with displaced cheek teeth. These displacements were believed to be developmental in 16 cases and acquired in the remaining 7 cases. Long-term response to treatments, that included removal of overgrowths and extraction of teeth with deep secondary periodontal disease was excellent for most disorders except diastemata.

  2. Factors influencing permanent teeth eruption. Part one--general factors.

    PubMed

    Almonaitiene, Ruta; Balciuniene, Irena; Tutkuviene, Janina

    2010-01-01

    Variation in the normal eruption of teeth is a common finding, but significant deviation from established norms should alert the clinician to take some diagnostic procedures in order to evaluate patient health and development. Disturbance in tooth eruption time could be a symptom of general condition or indication of altered physiology and craniofacial development. The aim of this review is to analyze general factors that could influence permanent teeth eruption. The articles from 1965 to 2009 in English related to topic were identified. 84 articles were selected for data collection. Although permanent teeth eruption is under significant genetic control, various general factors such as gender, socioeconomic status, craniofacial morphology, body composition can influence this process. Most significant disturbance in teeth emergence is caused by systemic diseases and syndromes.

  3. On the linearization of eruption series of the permanent teeth.

    PubMed

    Kanno, R

    1997-11-01

    In order to confirm the linearization of permanent eruption, Masuyama's linearization method was applied to the data of Kitamura's study. At first, we considered the eruption age t alpha i of permanent teeth T alpha, where alpha corresponds a tooth of every description, and examined the linear regression of Y alpha i = log10 t alpha i on m(y) alpha (the mean of Y alpha i with respect to i), but the result was not good. For the correlation coefficient r between two variables in linear regression, the percentage of subjects with r > or = 0.970 was only 10.3% in males and 28.8% in females in Kitamura's study. Next we took notice of the eruption age u beta i of each tooth, which is the beta-th in order of eruption. The fitness of the linear regression of Z beta i = log10 u beta i on mz beta (the mean of Z beta i) was very good. The percentage of subjects with r > or = 0.970 increased to 80.0% in males and 86.0% in females. Then we used m(y) (beta) (rearranged m(y) alpha in order of increasing size) instead of mz beta as an independent variable in the linear regression. The degree of the linearization was slightly inferior to that using mz beta. In every linearization, a quasi-fixed point with coordinates (C, C) existed on the linearized dentition plot, where the value of C was almost equal in each way, i.e., C = 10.23 (years) for males and C = 8.91 (years) for females in Kitamura's data. This linearized dentition plot will be useful in detecting certain growth disturbances. The existence of a quasi-fixed point may be useful in forecasting the age of the eruption of subsequent teeth, once the first eruption is observed.

  4. Odontomas—silent tormentors of teeth eruption, shedding and occlusion

    PubMed Central

    Kulkarni, Vinaya Kumar; Deshmukh, Jeevanand; Banda, Naveen Reddy; Banda, Vanaja Reddy

    2012-01-01

    Odontomas are the most common odontogenic tumours of the jaws, characterised by their slow growth and non-aggressive behaviour. They usually remain asymptomatic, and are diagnosed on routine radiographs. Clinically, they are often associated with delayed eruption or impaction of permanent teeth and retained primary teeth. The purpose of this paper is to review the literature and report two cases of odontomas. In the first case, a compound odontoma was associated with an unerupted maxillary permanent right central incisor, in an 11-year-old boy. In the second case, a 12-year-old girl had retained mandibular primary left central incisor and its unerupted successor was associated with a compound odontoma, a site considered rare for compound odontoma to occur. The clinical features, diagnosis and treatment of these cases have been discussed. PMID:23242095

  5. Can the presence of erupting or exfoliating teeth increase the salivary lactobacillus count?

    PubMed

    Wikner, S; Moum, I

    1987-04-01

    The salivary lactobacillus count was assessed during school attendance among 1734 7-15-yr-old children and related to the number of teeth erupting within each age group. The prevalence of extremely low lactobacillus counts (less than or equal to 10(3)) was inversely correlated with the number of erupting teeth (P less than 0.001) but the differences were small. High counts differed only by 7% between ages with the lowest and the highest mean number of erupting or exfoliating teeth tend to elevate the lactobacillus count in individuals. On a population level the effect is small.

  6. Teething.

    PubMed

    Leung, A K

    1989-02-01

    Teething does not appear to cause diarrhea, fever, rashes, seizures or bronchitis. It may be associated with some daytime restlessness, thumb sucking, gum rubbing, drooling and temporary loss of appetite. It is not clear whether these signs are developmental in origin or are actually related to tooth eruption. Illness occurring with teething should be thoroughly evaluated so that a serious systemic disturbance is not overlooked.

  7. 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

  8. The effect of shortening incisor teeth on the eruption rates and lengths of the other incisors in the rat.

    PubMed

    Burn-Murdoch, R A

    1995-06-01

    The eruption rates and lengths of all four incisor teeth in rats were measured by recording the position of marks on their labial surfaces at 2-day intervals, using calibrated graticules in microscope eyepieces and ether anaesthesia. When one lower incisor, or both a lower and upper incisor, were unimpeded, the other lower incisor shortened markedly before the next measurement and the uppers slowly lengthened, so that the sum of the lengths of the lower and upper impeded incisors temporarily fell, then returned to control levels. The lower and upper impeded incisors showed temporary accelerations of their eruption when the other incisors were unimpeded. When an upper incisor was unimpeded, the lower incisors lengthened, increasing the sum of the lengths of the lower and upper impeded incisors, and the eruption of the lower and upper impeded incisors was slowed. When there were two impeded incisors in one jaw and only one (left) impeded incisor in the other jaw, the unopposed right impeded incisor tended to be slower and longer than its neighbour and there were significant correlations between the differences in eruption rates and differences in tooth lengths. In all these cases, there are negative relations between eruption and length; increases in length occur with decreases in eruption rate. The simplest explanation for this is that the length changes arise partly from the voluntary behaviour of the rat and also from mechanical problems due to having one impeded incisor in one jaw and two in the other jaw; the length changes cause the eruption-rate changes.

  9. 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

  10. 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

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. Teething

    MedlinePlus

    ... provider. Tips to ease your child's teething discomfort: Wipe your baby's face with a cloth to remove the drool ... NOT use homeopathic remedies, as they may contain ingredients that are not safe for infants.

  16. Crown lengthening procedure following intentional endodontic therapy for correction of supra-erupted posterior teeth: Case series with long-term follow-up

    PubMed Central

    Patil, Shruti Arun; Kulkarni, Sudhindra; Thakur, Srinath; Naik, Balaram

    2016-01-01

    Context: The crown lengthening procedure (CLP) is routinely carried out to correct gingival levels and achieve esthetic contours and adequate crown lengths for restorative purposes. Though the short-term outcomes have been found to be stable, long-term results are not much reported. Aims: To evaluate the long-term stability of the marginal bone levels, gingival levels, and the status of the teeth, which underwent endodontic therapy, followed by CLP and final restorations. Settings and Design: Institutional setting, long-term case series. Materials and Methods: Case records of the patients who underwent CLP and endodontic therapy for corrections of the supra-erupted teeth to regain the lost interocclusal spaces were retrieved, and the cases with complete set of the clinical and radiographs were taken. All the cases were recalled and bone levels on the radiographs, bleeding on probing, probing pocket depths, and changes in the soft tissue margins were evaluated. Statistical Analysis Used: Descriptive analysis. Results: A total of 25 teeth had undergone CLP and endodontic therapy and final restorations for a minimum of 24 months. The mean post-restorative duration was 50.8 ± 22.48 months (range 24–96 months). All the teeth were functional and asymptomatic with 100% survival. Interdental bone loss of 1 mm, probing pockets of 5 mm, and 1 mm buccal recession were observed in 16% of the sites. The amount of interocclusal space regained was adequate to restore the missing teeth in the opposing arch. Conclusions: The CLP is a predictive procedure for correction of supra-erupted teeth. The survival of the teeth that underwent the procedure in the present study was 100% over 24–96 months. PMID:27041850

  17. 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.

  18. Patients' perceptions of recovery after surgical exposure of impacted maxillary teeth treated with an open-eruption surgical-orthodontic technique.

    PubMed

    Chaushu, S; Becker, A; Zeltser, R; Vasker, N; Chaushu, G

    2004-12-01

    This study assessed patient perceptions of immediate post-operative recovery after the surgical exposure of impacted maxillary teeth with an open-eruption technique. Thirty patients (24 females and six males) underwent surgical exposure of 39 impacted maxillary teeth using this technique. After surgery the patients were contacted by telephone daily for 7 days, to complete a health-related quality of life (HRQOL) questionnaire, which assessed their perception of recovery in four main areas: pain, oral function, general activity, and other symptoms. Severe pain was reported by 30 per cent of the patients in the first post-operative day (POD 1), which declined to 6.7 per cent by POD 6. Consumption of analgesics declined gradually over the post-operative days (POD 1: 80 per cent, POD 7: 20 per cent). Difficulty in eating required 5 days to reach minimal levels; enjoying everyday food, 2.5 days; school attendance, limitations in daily routine, swallowing, and speech, 2 days each; swelling, bad taste/smell, 1.5 days each; within 1 day all other measures attained minimal levels. The need for bone removal during the exposure resulted in delayed recovery with regard to the ability to eat. In general, females reported delayed recovery for pain. The present data may serve as basic guidelines against which future studies which assess post-operative management of patients after surgical exposure of impacted teeth by an open-eruption technique may be compared.

  19. Management of Ectopically Erupting Maxillary Incisors: A Case Series

    PubMed Central

    Suresh, Kotumachagi Sangappa; Uma, HL; Nagarathna, J

    2015-01-01

    ABSTRACT Eruption disturbances related to the position include ectopic eruption and transpositions. The occurrence of ectopic eruption is most commonly associated with maxillary incisors. The normal eruption, position and morphology of these teeth are crucial to craniofacial development, facial esthetics as well as phonetics. It is essential that the clinicians have thorough knowledge of the eruption disturbances in order to make an appropriate, as well as timely intervention, as dictated by the complexity of the problem. How to cite this article: Suresh KS, Uma HL, Nagarathna J, Kumar P. Management of Ectopically Erupting Maxillary Incisors: A Case Series. Int J Clin Pediatr Dent 2015;8(3):227-233. PMID:26604543

  20. Management of Ectopically Erupting Maxillary Incisors: A Case Series.

    PubMed

    Suresh, Kotumachagi Sangappa; Uma, H L; Nagarathna, J; Kumar, Pravin

    2015-01-01

    Eruption disturbances related to the position include ectopic eruption and transpositions. The occurrence of ectopic eruption is most commonly associated with maxillary incisors. The normal eruption, position and morphology of these teeth are crucial to craniofacial development, facial esthetics as well as phonetics. It is essential that the clinicians have thorough knowledge of the eruption disturbances in order to make an appropriate, as well as timely intervention, as dictated by the complexity of the problem. How to cite this article: Suresh KS, Uma HL, Nagarathna J, Kumar P. Management of Ectopically Erupting Maxillary Incisors: A Case Series. Int J Clin Pediatr Dent 2015;8(3):227-233.

  1. Ectopic eruption of maxillary central incisor through abnormally thickened labial frenum: An unusual presentation.

    PubMed

    Gugnani, Neeraj; Pandit, I K; Gupta, Monika; Gugnani, Shalini; Vishnoi, Ashmi; Sabharwal, Ozasvita; Manhas, Swati

    2017-01-01

    Ectopic eruption is a deviation from the normal eruption pattern, making the tooth erupt out of its normal position, and possibly causing resorption of adjacent primary teeth. A wide range of etiological factors may be responsible for ectopic eruption of the teeth, so their management depends on the correction of the established etiological factor. The present case report describes an unusual case of ectopically erupted central incisor encased within an abnormally thickened labial frenum, which was treated by orthodontic repositioning of the ectopically erupting tooth after frenectomy.

  2. Attitude and beliefs of traditional birth attendants to prematurely erupted teeth of infants in urban local government areas in Ibadan, Nigeria.

    PubMed

    Bankole, Olubunmi; Taiwo, Juliana; Nasiru, Olukemi

    Traditional birth attendants (TBAs) can be invaluable in assisting to dispel myths commonly associated with natal/neonatal teeth. To ensure correct delivery of the message, baseline data of their beliefs is important. To assess the attitude and beliefs of some Nigerian TBAs to prematurely erupted teeth in infants, a total enumeration of the TBAs in the five urban Local Government Areas in Ibadan was conducted and 163 consenting TBAs were recruited using an interviewer-administered questionnaire. The attitude of the TBAs was that of fear and shock (35.6%) while 30 (18.4%) will consider the child weird. Perceived causes of the variation include evil spirits (31.9%), contravening cultural taboos (9.2%), and prolonged gestation (4.9%). Beliefs on the effect of natal/neonatal teeth on the child include strange behavior (31.3%), child developing evil spiritual powers (41.1%), and mental retardation (3.1%). Practices included advising parents to get rid of/or hide the child (4.9%) and immediate extraction of the teeth with/without sacrifices (35.6%). There is an urgent need to address knowledge gaps by giving health education to TBAs.

  3. Effects of offset values for artificial teeth positions in CAD/CAM complete denture.

    PubMed

    Yamamoto, Shinta; Kanazawa, Manabu; Iwaki, Maiko; Jokanovic, Ana; Minakuchi, Shunsuke

    2014-09-01

    Recently, computer-aided design/computer-aided manufacturing (CAD/CAM) technology has been applied to the field of removable complete denture prosthodontics. We developed a system for fabricating complete dentures applying CAD/CAM technology. In this system, artificial teeth were bonded to the recesses of a milled denture base. However, the offset values needed for the recesses are not known. The purpose of the present study was to evaluate the accuracy of bonded artificial teeth positions in 0.00 (control), 0.10, 0.15, 0.20, and 0.25mm offset recess groups. Four types of artificial teeth, upper left central incisor (UL1), upper left canine (UL3), upper left first premolar (UL4), and upper left first molar (UL6), were used. Each type of artificial tooth was arranged at regular intervals on the denture base model with the CAD software. These data were defined as the master data. The artificial teeth parts were subtracted from the denture base model by Boolean logic operations in order to make recesses, and the recesses were then offset in five values. Based on these denture base data, prepolymerized resin blocks were milled (n=3). After bonding artificial teeth on the milled denture base model, a cone beam computed tomography (CBCT) scan was performed to obtain scanned data. Deviations between the master data and the scanned data were calculated. Based on the results, the optimal offset values were found to be 0.15-0.25mm for UL1, 0.15 and 0.25mm for UL3, 0.25mm for UL4, and 0.10-0.25mm for UL6.

  4. The effects of impacted premaxillary supernumerary teeth on permanent incisors

    PubMed Central

    Jung, Yun-Hoa; Kim, Ji-Yeon

    2016-01-01

    Purpose The aim of this study was to examine the radiographic features associated with impacted premaxillary supernumerary teeth, to determine the relationship between their characteristics and their effects on permanent incisors, and to investigate the types of orthodontic treatment that patients received after the extraction of impacted supernumerary teeth. Materials and Methods The clinical records and radiographs of 193 patients whose impacted premaxillary supernumerary teeth were removed were retrospectively reviewed, and 241 impacted supernumerary teeth were examined. Cone-beam computed tomographic images and panoramic radiographs were examined to determine the number, location, sagittal position, orientation, and morphology of the supernumerary teeth. Their effects on permanent incisors and the orthodontic treatment received by patients after the extraction of the supernumeraries were also investigated. Results Supernumerary teeth were most frequently observed in the central incisor region, in the palatal position, in the inverted orientation, and were most commonly conical in shape. The most common complication was median diastema, followed by displacement and delayed eruption of the adjacent incisors. Ten (71.4%) of the 14 odontomas showed delayed eruption of the adjacent incisors. Displacement of the incisors was more frequently observed in association with supernumerary teeth with tuberculate or supplemental shapes. Orthodontic traction was most frequently performed after the removal of odontomas. In 32 cases (13.3%), permanent incisors erupted after the orthodontic creation of sufficient space. Conclusion Median diastema was most common complication. The delayed eruption of incisors was common in supernumerary teeth with a vertical orientation and an odontoma shape. PMID:28035303

  5. 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.

  6. Triple Teeth: Report of an Unusual Case

    PubMed Central

    Babaji, Prashant; Prasanth, M. A.; Gowda, Ajith R.; Ajith, Soumya; D'Souza, Henston; Ashok, K. P.

    2012-01-01

    Fusion or synodontia is a union of two or more than two developing teeth. Commonly fusion occurs between teeth of the same dentition, mixed dentition, or between normal and supernumerary teeth. Fused primary teeth present with several clinical problems like caries, periodontal problem, arch asymmetry, delayed eruption, ectopic eruption of succedaneous teeth, aesthetic, and other complications. This paper presents a rare and unusual case of triple teeth in mandibular primary dentition. PMID:23346424

  7. Natal teeth: a review.

    PubMed Central

    Leung, Alexander K. C.; Robson, William Lane M.

    2006-01-01

    The incidence of natal teeth is approximately 1:2,000 to 1:3,000 live births. The most commonly affected teeth are the lower primary central incisors. Natal teeth usually occur in pairs. The eruption of more than two natal teeth is rare. The majority of natal teeth represent the early eruption of normal primary deciduous dentition. Less than 10% of natal teeth are supernumerary. 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 discomfort during suckling, sublingual ulceration, laceration of the mother's breasts and aspiration of the teeth. A dental roentgenogram is indicated to differentiate the premature eruption of a primary tooth from a supernumerary tooth. Tooth extraction is indicated if the tooth is supernumerary or excessively mobile. If the tooth does not interfere with breastfeeding and is otherwise asymptomatic, no treatment is necessary. Images Figure 1 PMID:16708508

  8. Prevalence, etiology, diagnosis, treatment and complications of supernumerary teeth

    PubMed Central

    Ata-Ali, Fadi; Peñarrocha-Oltra, David; Peñarrocha-Diago, Miguel

    2014-01-01

    The aim of this article was to review the literature on supernumerary teeth, analyzing their prevalence, etiology, diagnosis, treatment and possible complications. An electronic search was made in the Pubmed-Medline database up to January 2014 using the key search terms “multiple supernumerary teeth” (n=279), “prevalence supernumerary teeth” (n=361), and “supernumerary teeth” (n=2412). In addition to the articles initially identified, others were included in the review proceeding from a manual search and from any references considered of relevance. Supernumerary teeth are those that exceed the normal dental formula. They are more common in men, more common in the upper maxilla, and more prevalent in permanent dentition. Complications associated with supernumerary teeth include dental impaction, delayed eruption, ectopic eruption, overcrowding, spacing anomalies and the formation of follicular cysts. The treatment of supernumerary teeth depends on their type, position, and possible complications, detected clinically and radiographically. No clear consensus exists as to the best time to extract unerupted supernumerary teeth. Key words:Hyperdoncia, supernumerary teeth, impacted teeth, treatment, permanent teeth, deciduous teeth. PMID:25593666

  9. 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.

  10. The Ultrasonographic Determination of the Position of the Mental Foramen and its Relation to the Mandibular Premolar Teeth

    PubMed Central

    Motara, Feroza; Moolla, Muhammed

    2016-01-01

    Introduction The position of the mental foramen has been well researched in cadaver specimens, radiographically as well as intraoperatively. To our knowledge, this landmark study is the first to make use of ultrasonography in a study population to determine the position of the mental foramen in relation to the mandibular premolar teeth. Ultrasonography has great potential to further revolutionize the practice of medicine and dento-maxillofacial surgery. Aim To make use of ultrasound to determine the position of the mental foramen and its relation to the mandibular premolar teeth. Materials and Methods One hundred Black and Caucasian subjects were enrolled. A high frequency (8MHz) transducer (PLF.805ST) of a diagnostic ultrasound system (model SSA-510A) was applied above the inferior border of the mandible, just lateral to the mentum. With the marker of the transducer pointing cranially, the position of the mental foramen in relation to the closest mandibular premolar tooth was determined. The position was compared across race, sex and age groups. Results All mental foramina (100%) were visualised. Overall the most frequent position of the mental foramen was in line with the long axis of the second premolar on the right (44%) and between the first and second premolars on the left (44%). There were no statistical differences (p >0.05) between race groups, sex and age groups with regard to the position of the mental foramen in relation to the mandibular premolars. However, in Blacks, the most frequent position of the mental foramen was in line with the long axis of the second premolar and in Caucasians the most common position was between the first and second premolars. The most frequent position of the mental foramen in females was in line with the long axis of the second premolar on the right and between the first and second premolars on the left. In males, the most frequent position of the mental foramen was in line with the long axis of the second premolar

  11. Epidermodysplasia Verruciformis-like Skin Eruption in an HIV-positive Patient.

    PubMed

    Boza, Juliana C; Peruzzo, Juliano; de Oliveira, Fabiana Bazanella; Nazar, Fernanda Luca; Bakos, Renato Marchiori

    2014-12-01

    Epidermodysplasia Verruciformis-like skin eruption is a rare syndrome that usually occurs in patients with immunodeficiency, predisposing them to infections with human papilloma β virus (HPV). We report here an HIV patient presenting with this syndrome.

  12. 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.

  13. 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

  14. [Electromyographic evaluation of functional status of temporal muscles and mastication muscles in patients with close position of frontal teeth in cases of different occlusion].

    PubMed

    Krechina, E K; Lisovskaia, V T; Pogabalo, I V

    2010-01-01

    Functional status of mastication muscles in 44 patients of the age 19-35 years with close position of frontal teeth and different occlusion variants was studied. General electric activity of mastication and temporal muscles (IMPACT, mkV/s), index of proportional activity of symmetric muscles (capital ER, Cyrilliccapital O, Cyrilliccapital ES, Cyrillic, %), activation index (ATTIV, %) and torque coefficient (TORS, %) were determined. According to the received results in patients with close position of frontal teeth and different occlusion variants some disbalance was disclosed in the work of mastication muscles that testified to functionally unstable occlusion and the necessity of its correction.

  15. Transposition of teeth: A forensic perspective

    PubMed Central

    Nambiar, Supriya; Mogra, Subraya; Shetty, Surendra

    2014-01-01

    Dental identification plays a key role in mass casualties and is usually based on disturbances of tooth eruption, malocclusions and/or previous dental treatments, changes brought about by age, pathological conditions and developmental disturbances. Tooth transposition is a disturbance of tooth eruption and is defined as change in the position of two adjacent teeth within the same quadrant. This review aims to discuss the prevalence and the etiology of transposition through a literature survey and to discuss its importance and implications as pertaining to the field of forensics. In summary, transposition is a rare and severe positional anomaly that represents a challenge for a dentist. It requires a keen eye on the part of the forensic pathologist to identify the condition. PMID:25177135

  16. Orthodontic movement in deciduous teeth

    PubMed Central

    Consolaro, Alberto

    2015-01-01

    Deciduous teeth exfoliate as a result of apoptosis induced by cementoblasts, a process that reveals the mineralized portion of the root while attracting clasts. Root resorption in deciduous teeth is slow due to lack of mediators necessary to speed it up; however, it accelerates and spreads in one single direction whenever a permanent tooth pericoronal follicle, rich in epithelial growth factor (EGF), or other bone resorption mediators come near. The latter are responsible for bone resorption during eruption, and deciduous teeth root resorption and exfoliation. Should deciduous teeth be subjected to orthodontic movement or anchorage, mediators local levels will increase. Thus, one should be fully aware that root resorption in deciduous teeth will speed up and exfoliation will early occur. Treatment planning involving deciduous teeth orthodontic movement and/or anchorage should consider: Are clinical benefits relevant enough as to be worth the risk of undergoing early inconvenient root resorption? PMID:25992982

  17. Orthodontic movement in deciduous teeth.

    PubMed

    Consolaro, Alberto

    2015-01-01

    Deciduous teeth exfoliate as a result of apoptosis induced by cementoblasts, a process that reveals the mineralized portion of the root while attracting clasts. Root resorption in deciduous teeth is slow due to lack of mediators necessary to speed it up; however, it accelerates and spreads in one single direction whenever a permanent tooth pericoronal follicle, rich in epithelial growth factor (EGF), or other bone resorption mediators come near. The latter are responsible for bone resorption during eruption, and deciduous teeth root resorption and exfoliation. Should deciduous teeth be subjected to orthodontic movement or anchorage, mediators local levels will increase. Thus, one should be fully aware that root resorption in deciduous teeth will speed up and exfoliation will early occur. Treatment planning involving deciduous teeth orthodontic movement and/or anchorage should consider: Are clinical benefits relevant enough as to be worth the risk of undergoing early inconvenient root resorption?

  18. Three-dimensional positional changes of teeth adjacent to posterior edentulous spaces in relation to age at time of tooth loss and elapsed time.

    PubMed

    Petridis, Haralampos P; Tsiggos, Nikolaos; Michail, Achilleas; Kafantaris, Sotirios N; Hatzikyriakos, Andreas; Kafantaris, Nikolaos M

    2010-06-01

    The purpose of this study was to study the stability of teeth adjacent to posterior edentulous spaces and correlate it with patient age and time lapse since tooth loss. Dental casts, panoramic radiographs, and questionnaires of patients treated in a University setting were employed. Teeth adjacent and opposing posterior edentulous spaces were examined for the following parameters: Supraeruption, rotation, space closure, and axial inclination. One hundred twenty three patients with 229 edentulous spaces were analyzed. Statistical analysis showed that the effects of "jaw", "gender", and "age group at the time of tooth loss" were not significant for any of the variables tested. The effect of time lapse since tooth loss was significant regarding the "amount of distal tooth inclination" (P<0.001), the "amount of distal tooth rotation" (P=0.004), and "space closure" (P=0.038). Post-hoc analysis of the "amount of distal tooth inclination" revealed a marked increase in inclination 5 years after tooth loss. Within the limitations of this study, it was concluded that in the group of patients studied, minor positional changes in teeth opposing or adjacent to posterior edentulous spaces had occurred. The greatest changes in position were recorded for mandibular teeth distal to edentulous spaces.

  19. Eruption disturbances: an aetiological-cum-management perspective.

    PubMed

    Nagpal, A; Sharma, G; Sarkar, A; Pai, K M

    2005-01-01

    Failure of permanent teeth to erupt without any known cause is a rare incident. We report a case of multiple unerupted permanent teeth and make an effort to predict all possible causes of non-eruption of permanent teeth clinically and radiographically. It is essential to diagnose and treat eruption disturbances as early as possible because treatment at a later stage is usually more complicated due to the tendency of malocclusion to increase with time and reduced ability of remaining dentition to adjust.

  20. Teething Tots

    MedlinePlus

    ... Your 1- to 3-Month-Old Feeding Your 4- to 7-Month-Old Feeding Your 8- to 12-Month-Old Feeding Your 1- to 2-Year-Old Teething ... en español La dentición en los niños Teething, the emergence of the first teeth through ...

  1. Supernumerary Teeth in Nepalese Children

    PubMed Central

    Singh, Varun Pratap

    2014-01-01

    Objective. The objectives of the present study were to investigate the prevalence and characteristics of supernumerary teeth in a patient sample of Nepalese children. Study Design. A survey was performed on 2684 patients (1829 females and 1035 males) ranging in age from 6 to 14 for the presence of supernumerary teeth. For each patient with supernumerary teeth the demographic variables (age and sex), number, location, eruption status, and morphology were recorded. Descriptive statistics were performed. Results. Supernumerary teeth were detected in 46 subjects (1.6%), of which 26 were males and 20 were females with a male : female ratio of 1.3 : 1. The most commonly found supernumerary tooth was mesiodens followed by maxillary premolars, maxillary lateral incisor, and mandibular lateral incisor. Of the 55 supernumerary teeth examined, 58.18% (n = 32) had conical morphology, followed by tuberculate (30.90%, n = 17) and supplemental (10.90%, n = 6) forms. The majority of the supernumerary teeth were erupted (56.36%, n = 31). Conclusion. The prevalence of supernumerary teeth in Nepalese children was found to be 1.6%, the most frequent type being mesiodens. Conical morphology was found to be the most common form of supernumerary tooth. PMID:25506609

  2. 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.

  3. The Use of Cone Beam Computed Tomography (CBCT) to Determine Supernumerary and Impacted Teeth Position in Pediatric Patients: A Case Report

    PubMed Central

    Nematolahi, Hossein; Abadi, Hamed; Mohammadzade, Zahra; Soofiani Ghadim, Mostafa

    2013-01-01

    A case of a compound odontoma which caused delayed eruption of right maxillary central incisor in a ten year old girl is presented with clinical and radiographic findings. The patient presented with complaint of a hard painless swelling in the right anterior region of the maxilla and absence of right maxillary central incisor. After clinical examination, periapical and occlusal radiographs of the mentioned region were taken. Impacted maxillary right central incisor was seen malformed shape on the intraoral radiographs. After taking a cone beam computed tomography (CBCT) a compound odontoma associated with the labial aspect of impacted maxillary right central incisor was diagnosed and then removed by simple local excision under local anesthesia. The removal of the odontoma was followed by forced eruption of the impacted central incisor. After three months the tooth returned to its original position. PMID:23487351

  4. Morphological and topographical characteristics of posterior supernumerary molar teeth: An epidemiological study on 25,186 subjects

    PubMed Central

    Altieri, Federica; Giansanti, Matteo; Di-Giorgio, Roberto; Calasso, Sabrina

    2014-01-01

    Objectives: To investigate the prevalence , gender difference , arch , morphology and position within the arch of supernumerary molar (SM) teeth in a referred Italian Caucasian population. Study Design: Records of 25,186 young patients were evaluated. Only data related to supernumerary teeth in the posterior region of the jaws were analyzed. The diagnosis of hyperdontia was formulated during the clinical and radiological examinations based on panoramic radiographs. Statistical analysis was conducted at level of subjects in the assessment of prevalence of SMs and sex ratio. Statistical analysis was conducted at level of teeth according to their morphological and topographic characteristics. The analysis of association between supernumerary morphology and arch, between supernumerary position and arch and between morphology and position was performed using the χ2 test (P≤ 0.05). Results: 61 posterior supernumerary teeth were found in 45 patients. The male to female ratio was 2.5:1 ;the mean age was 21.23 (IC:95%).The SMs were found more frequently in the maxilla (62.3%) than in the mandible; supernumerary teeth (60.7%) were more frequent than supplemental teeth. The SMs were mostly of tuberculate shape (56.8%) and paramolars teeth (64.9%) were more common than distomolars. 54% of teeth were erupted in the arch. No statistically significant relationship were found between the supernumerary teeth shape and the arch (P= 0.087) , between supernumerary teeth position and the arch (P=0.511) and between morphology and position (P=0.216). Conclusions: Epidemiological studies related to supernumerary teeth can be useful to clinicians in the early diagnosis of this anomaly. In this retrospective study the prevalence of SMs was 0.18%. SMs were more frequent in males and in the maxilla. Supernumerary were more frequent than supplemental; the conical morphology and paramolar position were the most common shape and position. Key words:Hyperdontia, prevalence, supernumerary

  5. 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

  6. Eruption Pattern of Dentition and Its Medico-legal Significance.

    PubMed

    Karki, R K

    2016-01-01

    Background The eruption pattern of temporary and permanent teeth are fairly constant with the growing age. So the age determination of an individual by examination of teeth is one of the accepted methods in legal system. A review of the literature shows there are differences in eruption pattern between different populations mainly due to variations in the constitutions and environment, so highlighting the importance of this study to the Nepalese population. Objective To assess the eruption age of temporary and permanent teeth in Nepalese population and compared the eruption age with other groups. Method This cross-sectional study, included 450 subjects, aged between six months to 25 years selected by simple random sampling method. The determinant variable such as age and number of teeth was recorded. Result Eruption of temporary and permanent teeth is slightly delayed in Nepalese population compared with others. First temporary tooth to erupt is lower central Incisor at around eight months and last to erupt is second molar at around 28 months. For permanent tooth, first molar erupts at around seven years and second molar erupts by 14 years. Eruption of third molar (wisdom tooth) varies from 18 to 25 years. Conclusion This study provides a model data on eruption age of teeth which is first study of its kind in Nepal. The findings of this study will help as a reference data for optimal use in clinical, academic and research activities especially in Nepalese population. Medico legally it helps in estimation of age along with other parameters.

  7. 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

  8. Clinical and radiological evaluation of inverse impaction of supernumerary teeth

    PubMed Central

    Kurklu, Esma; Gencay, Koray; Ak, Gulsum

    2013-01-01

    Objective: To describe the clinical and radiological features of children with inverted supernumerary teeth. Study Design: Thirty eight patients with inverted supernumerary teeth (ST) were enrolled in this descriptive and restrospective study. Data from patient records including age, gender, status of dentition, number of ST, number of ST in inverted position, coexistence of ST in inverted and normal direction of eruption, location, orientation, morphology, clinical complications, management and radiography were assessed during 3-years period. Results: Thirty eight patients with a mean age of 9.10±1.97 years (range:6-13) and a strong male preponderance of 3.7:1 (male:30, female:8) had a total of 69 ST, of which 41 were in inverted position. Thirty five patients had one (92.1%) inverted tooth, whereas 3 patients had two inverted teeth per case (7.9%). All cases were located in the maxilla. Midline was the most frequent site for the single inverted supernumerary tooth in 18 (47.4%) patients, followed equally by the right and left premaxillary region in 10 patients each (26.3%). Regarding morphology, 30 patients had conical (78.9%) and 8 (21.1%) had incisiform ST. No tuberculate shaped ST was detected. There was no statistically significant difference between number of inverted teeth and delayed tooth eruption, diastema, local malocclusion, palatinal swelling (p>0.05). There was no statistically significant difference between complications and age (p>0.05). Surgical removal at the time of diagnosis with subsequent follow-up during completion of permanent dentition was the treatment approach in all cases. Conclusions: Thorough clinical examination followed by a comprehensive radiographic screening is the crucial determinant of an accurate diagnosis of an impacted ST. Early diagnosis and timely management are key factors to prevent or minimize the complications, which may influence function and esthetics of the teeth and even psychological condition of the growing

  9. Late Developing Supernumeraries in a Case of Nonsyndromic Multiple Supernumerary Teeth

    PubMed Central

    Bozkurt, Mine; Tüzüner Öncül, Ayşegül; Göçer, Rukiye; Sarı, Şaziye

    2015-01-01

    Objective. This case report presents 3-year follow-up of a case of nonsyndromic multiple supernumerary teeth (NSMST) with 11 supernumerary teeth, 2 of which showed subsequent formation. Case Report. A 10-year-old girl was referred to the dental clinic with the chief complaint of delayed eruption. Radiographic examination showed 9 retained supernumerary teeth. The treatment plan consisted of extraction of the supernumerary teeth and associated primary teeth in order to allow the permanent teeth to erupt. After 2 years of follow-up, 2 additional supernumerary teeth were observed. Conclusion. Regular follow-up for late forming supernumeraries is crucial for NSMST cases. PMID:25649422

  10. Comparison of conventional and semilunar coronally positioned flap techniques for root coverage in teeth with cervical abrasion restored with pink resin.

    PubMed

    Santos, Felipe Rychuv; Storrer, Carmen Lucia Mueller; Cunha, Emanuelle Juliana; Ulbrich, Lucienne M; Lopez, Camilo Andress Villabona; Deliberador, Tatiana Miranda

    2017-01-01

    Gingival recession is the most common mucogingival defect, characterized by apical migration of the gingival margin from the cementoenamel junction and root exposure. Several surgical techniques are reported for the treatment of gingival recession. Here we present a comparison of the conventional (coronally advanced flap) and semilunar coronally positioned flap techniques for root coverage in teeth with cervical abrasion restored with pink resin that mimics the color of the gingiva. Although the conventional technique is more predictable, we found that both techniques were effective in achieving satisfactory and esthetic root coverage.

  11. Comparison of conventional and semilunar coronally positioned flap techniques for root coverage in teeth with cervical abrasion restored with pink resin

    PubMed Central

    Santos, Felipe Rychuv; Storrer, Carmen Lucia Mueller; Cunha, Emanuelle Juliana; Ulbrich, Lucienne M; Lopez, Camilo Andress Villabona; Deliberador, Tatiana Miranda

    2017-01-01

    Gingival recession is the most common mucogingival defect, characterized by apical migration of the gingival margin from the cementoenamel junction and root exposure. Several surgical techniques are reported for the treatment of gingival recession. Here we present a comparison of the conventional (coronally advanced flap) and semilunar coronally positioned flap techniques for root coverage in teeth with cervical abrasion restored with pink resin that mimics the color of the gingiva. Although the conventional technique is more predictable, we found that both techniques were effective in achieving satisfactory and esthetic root coverage. PMID:28331369

  12. Teething Tots

    MedlinePlus

    ... the first set of teeth will fall out, tooth decay makes them fall out more quickly, leaving gaps ... brush and floss. Another important tip for preventing tooth decay: Don't let your baby fall asleep with ...

  13. Your Teeth

    MedlinePlus

    ... used by people millions of years ago when humans had larger jaws and ate food that needed a lot of chewing. It's believed that they're called wisdom teeth because they come in later in life, when ...

  14. Factors affecting self-eruption of displaced permanent maxillary canines.

    PubMed

    Smailienė, Dalia; Sidlauskas, Antanas; Lopatienė, Kristina; Guzevičienė, Vesta; Juodžbalys, Gintaras

    2011-01-01

    The aim of this study was to examine the possibility of the spontaneous eruption of displaced unerupted maxillary canines after the extraction of the deciduous canine and dental arch expansion and to determine the impact of initial canine position on treatment success rate. Materials and METHODS. The study sample included 50 patients (mean age, 13.5 years [SD, 2.2]) with unilaterally displaced unerupted maxillary canines. Deciduous canines were extracted, and the space for displaced canine was created at the beginning of the study. The follow-up period for the spontaneous eruption was 12 months. The initial vertical, horizontal, labio-palatal position and angle of inclination to the midline of the displaced canine were assessed on panoramic radiographs. RESULTS. Only 42% of displaced canines erupted spontaneously within one-year period (52.9% of labially displaced canines and 36.4% of palatally displaced canines). A significant difference of inclination was determined between spontaneously erupted and unerupted teeth in the labially displaced canine group (P<0.01), with no difference in the palatally displaced canine group. The receiver operating characteristic curve analysis showed that the critical angle of inclination for the spontaneous eruption of the retained canine was 20º (sensitivity 0.759; specificity 0.571; P<0.05). The majority of unerupted canines (75.9%) were inclined more than 20º. The initial height of canine was crucial for spontaneous eruption (sensitivity 0.966; specificity 0.81; P<0.001). This was true for both palatal and labial cases. CONCLUSIONS. The initial vertical position of the labially and palatally displaced canines and the inclination of the labially displaced canines were the most important predictors for spontaneous eruption of the cuspid.

  15. Erupted complex odontoma delayed eruption of permanent molar.

    PubMed

    Ohtawa, Yumi; Ichinohe, Saori; Kimura, Eri; Hashimoto, Sadamitsu

    2013-01-01

    Odontomas, benign tumors that develop in the jaw, rarely erupt into the oral cavity. We report an erupted odontoma which delayed eruption of the first molar. The patient was a 10-year-old Japanese girl who came to our hospital due to delayed eruption of the right maxillary first molar. All the deciduous teeth had been shed. The second premolar on the right side had erupted, but not the first molar. Slight inflammation of the alveolar mucosa around the first molar had exposed a tooth-like, hard tissue. Panoramic radiography revealed a radiopaque mass indicating a lesion approximately 1 cm in diameter. The border of the image was clear, and part of the mass was situated close to the occlusal surface of the first molar. The root of the maxillary right first molar was only half-developed. A clinical diagnosis of odontoma was made. The odontoma was subsequently extracted, allowing the crown of the first molar to erupt almost 5 months later. The dental germ of the permanent tooth had been displaced by the odontoma. However, after the odontoma had been extracted, the permanent tooth was still able to erupt spontaneously, as eruptive force still remained. When the eruption of a tooth is significantly delayed, we believe that it is necessary to examine the area radiographically. If there is any radiographic evidence of a physical obstruction that might delay eruption, that obstruction should be removed before any problems can arise. Regular dental checkups at schools might improve our ability to detect evidence of delayed eruption earlier.

  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. Effect of slow forced eruption on the vertical levels of the interproximal bone and papilla and the width of the alveolar ridge

    PubMed Central

    Kwon, Eun-Young; Lee, Ju-Youn

    2016-01-01

    Objective Forced eruption has been proposed for the reconstruction of deficient bone and soft tissue. The aim of this study was to examine the changes in the alveolar ridge width and the vertical levels of the interproximal bone and papilla following forced eruption. Methods Patients whose hopeless maxillary anterior teeth were expected to undergo severe bone resorption and soft tissue recession upon extraction were recruited. In addition, patients whose maxillary anterior teeth required forced eruption for restoration due to tooth fracture or dental caries were included. Before and after forced eruption, the interproximal bone height was measured by radiographic analysis, and changes in the alveolar ridge width and the interproximal papilla height were measured with an acrylic stent. Results This prospective study demonstrated that the levels of the interproximal alveolar bone and papilla were significantly increased by 1.36 mm and 1.09 mm, respectively, in the vertical direction. However, the alveolar ridge width was significantly reduced by an average of 0.67 mm in the buccolingual direction. The changes in the level of the interproximal alveolar bone and papilla were positively correlated. Conclusions Although the levels of the interproximal bone and papilla were significantly increased, the alveolar ridge width was significantly decreased following forced eruption. There was a modest positive and significant correlation between the changes in the height of the interproximal alveolar bone and the papilla. Based on our findings, modification of vertical forced eruption should be considered when augmentation of the alveolar ridge width is required. PMID:27896212

  18. Natal and Neonatal Teeth: An Overview of the Literature

    PubMed Central

    Mhaske, Shubhangi; Yuwanati, Monal B.; Mhaske, Ashok; Ragavendra, Raju; Kamath, Kavitha; Saawarn, Swati

    2013-01-01

    The occurrence of natal and neonatal teeth is an uncommon anomaly, which for centuries has been associated with diverse superstitions among different ethnic groups. Natal teeth are more frequent than neonatal teeth, with the ratio being approximately 3 : 1. It must be considered that natal and neonatal teeth are conditions of fundamental importance not only for a dental surgeon but also for a paediatrician since their presence may lead to numerous complications. Early detection and treatment of these teeth are recommended because they may induce deformity or mutilation of tongue, dehydration, inadequate nutrients intake by the infant, and growth retardation, the pattern and time of eruption of teeth and its morphology. This paper presents a concise review of the literature about neonatal teeth. PMID:24024038

  19. [A Rare Case of Neonatal Teeth].

    PubMed

    Martins, Andreia A; Ferraz, Cláudia; Vaz, Rute

    2015-01-01

    Neonatal teeth is a rare disorder of tooth eruption, arising in the oral cavity, usually in the anterior mandible, in the first month of life. Its etiology is unknown. This condition can cause breastfeeding difficulties, besides aspiration or swallowing of the teeth. We describe the case of a premature infant in the second day of life presented with gingival edema, redness and discrete swelling in the region of the mandibular central incisors. Ten days later, two small teeth with hypermobility were detected. Extraction of those teeth was performed. With this clinical case we intend to show the rarity of this entity, especially in premature infants, the possible association with various syndromes and the need for a multifactorial approach to the treatment decision (extraction / conservative treatment).

  20. Creeping eruption

    MedlinePlus

    ... JavaScript. Creeping eruption is a human infection with dog or cat hookworm larvae (immature worms). Causes Hookworm eggs are found in the stool of infected dogs and cats. When the eggs hatch, the larvae ...

  1. Fixed drug eruption to tartrazine.

    PubMed

    Orchard, D C; Varigos, G A

    1997-11-01

    An 11-year-old girl with a recurrent fixed drug eruption to tartrazine on the dorsum of the left hand is presented. Oral provocation tests to both the suspected food, an artificially coloured cheese crisp, and to tartrazine were positive. This case highlights fire need to consider artificial flavours, colours and preservatives as potential culprits in classic drug eruptions.

  2. Orthodontic Management with Traction and Asymmetric Extraction for Multiple Impacted Permanent Maxillary Teeth – A Case Report

    PubMed Central

    Niu, Qiannan; Zhang, Liang; Dai, Juan; Li, Feifei; Feng, Xue

    2016-01-01

    Multiple impacted teeth are a rare eruption disturbance that increases the case complexity. In this article, we described a 13-year-old boy whose 5 permanent maxillary teeth were not erupted although their root formation was complete. The orthodontic treatment with traction and asymmetric extraction was performed to achieve a significantly improved functional and esthetic result. PMID:27857816

  3. The effect of a partial bite-raising splint on the inclination of upper and lower front teeth.

    PubMed

    Dahl, B L; Krogstad, O

    1983-10-01

    In a previous paper it was maintained that the effect of the permanent use of an anterior partial bite-raising splint was an intrusion of the front teeth and an eruption of the others. However, the effect might have been merely a change in the inclination of the front teeth. The present study comprised the same material as earlier. Linear and angular changes in the position of upper and lower incisors were measured on cephalometric radiographs. In the upper jaw a possible average proclination occurred, whereas in the lower jaw no or only a very small retroclination took place. The values were well within the method error, and it was concluded that the effect of the splint had been one of intrusion of the upper and lower front teeth and not merely a change in their inclination.

  4. 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

  5. Polymorphic light eruption sine eruption.

    PubMed

    Dover, J S; Hawk, J L

    1988-01-01

    We describe seven patients, four female and three male, who developed intense pruritus on sun-exposed skin without visible change. The clinical features resembled those of polymorphic light eruption (PLE) without rash. Four patients also occasionally developed typical PLE upon sun exposure, but sun-induced pruritus alone occurred most frequently. No patient was taking any drug therapy. One patient developed similar pruritus following solar simulated irradiation, and one following PUVA therapy. All other laboratory investigations were negative. Treatment with low dose UVB phototherapy or PUVA therapy was effective. The condition, which we have called polymorphic light eruption sine eruptione (PLESE), appears to be a variant of PLE not previously reported.

  6. Congenital oligodontia of the deciduous teeth and anodontia of the permanent teeth in a cat.

    PubMed

    Vieira, Ana Luiza S; Ocarino, Natalia de M; Boeloni, Jankerle N; Serakides, Rogeria

    2009-02-01

    This report describes a rare case of congenital oligodontia of the deciduous teeth and anodontia of the permanent teeth in a cat. According to cat's veterinarian, the patient had only two deciduous upper canines and no permanent teeth had ever erupted. Post-mortem evaluation showed a complete absence of teeth in the oral cavity and inflammatory lesions were not found on the gums. Histopathological analysis of serial sections of maxilla and mandible revealed absence of odontogenic epithelium, inflammatory cells and odontoclastic resorptive lesions. Diagnosis was confirmed after both the establishment that there were no remaining dental structures and the exclusion of other relevant diseases that lead to tooth loss, such as periodontal disease, renal fibrous osteodystrophy, odontoclastic resorptive lesions, ectodermal dysplasia and trauma.

  7. Dental eruption and exfoliation chronology in the ferret (Mustela putorius furo).

    PubMed

    He, Tailun; Friede, Hans; Kiliaridis, Stavros

    2002-08-01

    Substituting ferrets for rats and dogs as animal models for craniofacial research is favourable because of the similarity of many of the ferret's anatomical, metabolic and physiological features to those of man. Other advantages are cost-effectiveness and possibly less ethical controversy. However, information on the dental chronology of ferrets needs to be supplemented if this animal is to be promoted as an alternative model. Dental development was here examined in 16 ferrets (eight males, eight females) from three litters at between 12 and 90 days of age. Dental eruption and exfoliation were assessed and recorded every second day. The sequence of eruption of deciduous and permanent teeth was determined and data were analysed statistically. Also, any sex-related differences in eruption and exfoliation ages were defined. No deciduous incisors were observed to erupt in this group of animals. Other deciduous teeth erupted between the 19th and 31st postnatal days, and exfoliated between days 51 and 76. The time of eruption of the permanent teeth ranged from 42 to 77 days, in accordance with the stage of the mixed dentition. The female ferrets were generally ahead of the males in the exfoliation age of their deciduous teeth and the eruption age of their permanent teeth, but this, a sex difference did not apply to the eruption age of the deciduous teeth. These extended basic data might facilitate the introduction of this alternative experimental animal into craniofacial research.

  8. Eruptive xanthomas.

    PubMed

    Zaremba, Joanna; Zaczkiewicz, Andrzej; Placek, Waldemar

    2013-12-01

    Xanthomas are localized lipid deposits in the skin, tendons and subcutaneous tissue associated with lipid abnormality. The hyperlipidemia responsible for this disorder can be caused by a primary genetic defect, a secondary disorder, or both. That kind of skin exanthema may be the first signal of cardiovascular risk. We present a 24-year-old woman with a skin eruption that had appeared a few months earlier.

  9. Eruptive xanthomas

    PubMed Central

    Zaczkiewicz, Andrzej; Placek, Waldemar

    2013-01-01

    Xanthomas are localized lipid deposits in the skin, tendons and subcutaneous tissue associated with lipid abnormality. The hyperlipidemia responsible for this disorder can be caused by a primary genetic defect, a secondary disorder, or both. That kind of skin exanthema may be the first signal of cardiovascular risk. We present a 24-year-old woman with a skin eruption that had appeared a few months earlier. PMID:24494004

  10. Impacted Wisdom Teeth

    MedlinePlus

    ... Wisdom%20teeth&alt=sh. Accessed March 9, 2015. Toothache and infection. The Merck Manual Professional Edition. http:// ... dental_disorders/symptoms_of_dental_and_oral_disorders/toothache_and_infection.html?qt=Wisdom%20teeth&alt=sh. ...

  11. Brushing Your Child's Teeth

    MedlinePlus

    ... gov/ency/patientinstructions/000769.htm Brushing Your Child’s Teeth To use the sharing features on this page, ... how to brush their teeth on their own. Tooth and Gum Care for Young Children You should ...

  12. Bilateral eruption cysts associated with primary molars in both the jaws

    PubMed Central

    Gaddehosur, Chandan D; Gopal, Suma; Seelinere, Prashanth T; Nimbeni, Basavaraj S

    2014-01-01

    Disturbances of tooth development may result in anomalies which appear in the form of swelling of the overlying mucosa of the erupting deciduous or permanent teeth, mostly in children. Eruption cyst (EC), a benign cyst is one such lesion associated with erupting teeth. ECs usually present as solitary swellings on the alveolar ridge mucosa, whereas multiple ECs presenting simultaneously or in short intervals are unusual. Here, we present a rare case of four large bilateral ECs presenting with swellings and pain in the posterior region of each quadrant in the mouth. The treatment included surgical excision under general anaesthesia and exposure of the unerupted primary teeth. PMID:24789157

  13. Malocclusion (Misaligned Teeth)

    MedlinePlus

    ... misaligned. People who habitually suck their thumb or push their tongue up against their front teeth may cause the upper ... bands that apply force to slowly and gradually pull teeth into proper ... slightly ground down or built up so they meet better. After the teeth are ...

  14. Infundibula of equine maxillary cheek teeth. Part 1: Development, blood supply and infundibular cementogenesis.

    PubMed

    Suske, A; Pöschke, A; Schrock, P; Kirschner, S; Brockmann, M; Staszyk, C

    2016-03-01

    There is increasing interest in diseases of infundibula of equine maxillary cheek teeth. Imperfect infundibular cementogenesis has been recognized as an aetiopathological factor for the onset of infundibular necrosis. In this article, infundibular development was examined with particular attention to infundibular blood vessels and cementogenesis. Forty-one deciduous maxillary premolars prior to eruption were investigated using routine histological and immunohistological methods to visualize blood vessels and the enamel organ. Selected specimens were scanned by micro-computed tomography to analyze the three-dimensional configuration of the developing infundibulum. Before eruption, the infundibula are supplied by a central infundibular artery entering the infundibulum from an occlusal direction and by arteries entering the mesial infundibulum from the mesial aspect, and the distal infundibulum from the distal aspect. The central infundibular artery is destroyed shortly after tooth eruption but the lateral arteries remain vital for a time after eruption. As the arteries of the distal infundibulum are located in a more apical position, blood is received for a longer period compared with the mesial infundibulum. Cementogenesis starts first at distinct enamel in-foldings in the occlusal part of the infundibula, advancing in an apical direction. The results suggest a distinct asymmetry between the infundibula with the mesial infundibulum prone to incomplete cementogenesis due to early blood supply cessation.

  15. Ectopic eruption of the maxillary central permanent incisors and mandibular first permanent molars: report of an unusual case.

    PubMed

    Pomarico, Luciana; Primo, Laura Guimarães; Noce, Denise

    2006-10-01

    Ectopic eruption is a disturbance in which the tooth does not follow its usual course. Among its more important etiologic factors are macrodontism, shortened arch length, posterior positioning of the maxilla, atypical eruption angle, and genetic factors. This article reports a rare case of ectopic eruption of 4 permanent teeth, maxillary central incisors and mandibular first molars, in a child aged 7 years and 11 months, in which the treatment consisted of extracting the maxillary primary central incisors and making an orthodontic intervention on the mandibular arch. A bilateral fixed appliance containing 2 hooks with loops, 1 buccal and the other lingual, was placed on the mandibular primary first molars. The hooks were activated in a niche made of light-curing resin on the occlusal surface of the mandibular permanent molars, to bring about the distal drift of these teeth. After 6 months, complete eruption of the mandibular permanent molars occurred, and a slight displacement of the maxillary permanent central incisors toward the median line was noted. The importance of early, adequate treatment is discussed.

  16. Developmental disturbances of permanent teeth following trauma to the primary dentition.

    PubMed

    von Arx, T

    1993-02-01

    The topographic relationship of the apices of the primary teeth to the permanent tooth germs explains the potential for possible developmental disturbances of the permanent teeth after injuries to their predecessors. The anatomical, histologic and clinical aspects of permanent tooth malformation following trauma to the primary teeth are described. One hundred and fourteen children with originally 255 traumatized primary teeth have been re-examined (with an average period of 5.1 years after the trauma) to assess any developmental disturbances of the corresponding permanent teeth. Twenty-three per cent of partially or completely erupted permanent teeth showed developmental disturbances. The most frequent malformation was enamel hypoplasia including enamel discoloration and/or enamel defects. The highest prevalence of developmental disturbances of permanent teeth was found after intrusive injuries of primary teeth.

  17. 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

  18. Green teeth are a late complication of prolonged conjugated hyperbilirubinemia in extremely low birth weight infants.

    PubMed

    Battineni, Sireesha; Clarke, Paul

    2012-01-01

    Eruption of green, discolored teeth affecting the primary dentition has been described in association with congenital viral infection, sepsis, hemolytic jaundice, and cholestasis. The purpose of this paper was to present the cases of 3 extremely low birth weight preterm infants who were noted to have green teeth at the corrected ages of 10 to 12 months. All had a history of prolonged conjugated hyperbilirubinemia during their time in neonatal intensive care. For infants with prolonged conjugated hyperbilirubinemia, extreme preterm birth and/or extremely low birth weight may be additional risk factors predisposing to the eruption of green teeth in later infancy.

  19. Nonsurgical endodontic retreatment of fused teeth with transposition: a case report

    PubMed Central

    Noites, Rita Brandão; Martins, Miguel André Duarte; Paulo, Manuel Pedro da Fonseca

    2016-01-01

    Tooth transposition is a disorder in which a permanent tooth develops and erupts in the normal position of another permanent tooth. Fusion and gemination are developmental disturbances presenting as the union of teeth. This article reports the nonsurgical retreatment of a very rare case of fused teeth with transposition. A patient was referred for endodontic treatment of her maxillary left first molar in the position of the first premolar, which was adjacent to it on the distobuccal side. Orthopantomography and periapical radiography showed two crowns sharing the same root, with a root canal treatment and an associated periapical lesion. Tooth fusion with transposition of a maxillary molar and a premolar was diagnosed. Nonsurgical endodontic retreatment was performed. At four yr follow-up, the tooth was asymptomatic and the radiolucency around the apical region had decreased, showing the success of our intervention. The diagnosis and treatment of fused teeth require special attention. The canal system should be carefully explored to obtain a full understanding of the anatomy, allowing it to be fully cleaned and obturated. Thermoplastic techniques were useful in obtaining hermetic obturation. A correct anatomical evaluation improves the set of treatment options under consideration, leading to a higher likelihood of esthetically and functionally successful treatment. PMID:27200284

  20. 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

  1. Esthetic enhancement of a traumatized anterior tooth with a combination of forced eruption and tooth alignment: a case report

    PubMed Central

    Kang, So-Hee; Jin, Myoung-Uk; Kim, Sung-Kyo

    2016-01-01

    Exposing sound structure of a subgingivally fractured tooth using orthodontic extrusion is considered to be a conservative way to re-establish biologic width without sacrificing esthetics or jeopardizing periodontal support of neighboring teeth. When a misaligned tooth is traumatically involved, a more comprehensive approach combining tooth extrusion and re-alignment may be necessary for a successful restorative outcome. This case report describes a successful esthetic management of a patient with complicated crown-root fracture on the maxillary right central incisor and pre-existing malocclusion in the maxillary anterior region. Forced eruption along with re-alignment of teeth by orthodontic movement seems to allow re-positioning of the fracture line to a favorable position and correction of crowding, providing a better esthetic result. PMID:27508163

  2. The clinical prognosis of implants that are placed against super-erupted opposing dentition

    PubMed Central

    2016-01-01

    Objectives If teeth are missing, super-eruption of teeth in the opposing arch can occur in the area and can change the occlusal plane. When missing teeth are replaced with implants, the oral surgeon must determine whether or not the super-erupted teeth need to be treated in order to normalize the occlusal plane. In this study, we evaluated the clinical prognosis of dentition after implant placement and prosthetic treatment were completed in an occlusal plane altered by super-erupted teeth in the opposing arch without additional treatment of the super-erupted teeth. Materials and Methods Twenty-two patients (9 males, 13 females) were treated with implants and prosthetics without addressing the super-erupted opposing dentition from April 2004 to August 2012 at Seoul National University Bundang Hospital. A total of 33 implants were placed. Values of crestal bone loss, survival rates, and surgical and prosthetic complications for an average of 29.6 months after prosthetic loading were recorded. Results In one case, the cover screw was exposed after implant surgery. The mean crestal bone loss was 0.09±0.30 mm. Of the 33 implants, 31 survived, a survival rate of 93.94%. A prosthetic complication occurred in one case but functioned well after correction. Conclusion Favorable clinical results from prosthetic complications, crestal bone loss, and implant survival rates were exhibited in implants next to a super-erupted opposing tooth. PMID:27429935

  3. 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.

  4. Keeping Your Child's Teeth Healthy

    MedlinePlus

    ... prevent decay by applying a thin wash of resin (called a sealant) to the back teeth, where ... permanent teeth. But now, other materials like composite resins are becoming popular. Resins bond to the teeth ...

  5. Mouth and Teeth (For Parents)

    MedlinePlus

    ... system , but it does much more than get digestion started. The mouth — especially the teeth, lips, and ... Mouth and Teeth Do The first step of digestion involves the mouth and teeth. Food enters the ...

  6. 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

  7. 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.

  8. 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

  9. 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

  10. An ergodic approach to eruption hazard scaling

    NASA Astrophysics Data System (ADS)

    De la Cruz-Reyna, Servando; Mendoza-Rosas, Ana Teresa

    2014-05-01

    energy: through smaller (negative slope) or through larger (positive slope) eruptions while the latter is a measure of the volcano energy potential. Examples comparing the relative scales of the hazard defined with this procedure among Mexican volcanoes such as Colima, Citlaltepetl, El Chichón and Popocatepetl are presented to illustrate the method, aimed to provide an objective criterion to assess the relative hazard posed by different volcanoes.

  11. 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

  12. Primary failure of eruption combined with bilateral transmigration of mandibular canines, transposition, torus palatinus, and class III incisor relationship: A rare case report

    PubMed Central

    Elhag, Salma Babiker Idris; Abdulghani, Ashraf Sidig Idris

    2015-01-01

    Eruption disorders are numerous varying from delayed to complete failure of eruption. Primary failure of eruption (PFE) is a rare condition that involves arrested eruption of teeth with the absence of local or general contributory factors. Another rare and clinically challenging phenomenon is canine transmigration which is the intra-osseous movement of impacted canines across the midline. This report presents the first case of combined failure of eruption of multiple teeth with bilateral mandibular canine transmigration, transposition of upper canine and the first premolar, torus palatinus, and class III incisor relationship in a 33-year-old asymptomatic and nonsyndromic female patient. PMID:26929701

  13. 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.

  14. Eruption of third permanent molars after the extraction of second permanent molars. Part 2: Functional occlusion and periodontal status.

    PubMed

    Orton-Gibbs, S; Orton, S; Orton, H

    2001-03-01

    Functional occlusion and periodontal health were investigated after orthodontic treatment that involved extraction of second molars and after eruption of the third molars in 37 patients (25 female, 12 male). The mean age was 21 years 9 months (range, 16 years 1 month-30 years 5 months). The third permanent molars invariably erupted into a position that maintained good functional occlusion. Sixty-three percent of patients had canine guidance in lateral excursion; the remainder of patients had satisfactory group function. There were only 2 non-working side interferences in the sample, 1 from a recently erupted mandibular third molar. The periodontal health of the sample was generally excellent. Plaque score and bleeding on probing was very low (1.7% of sites). Periodontal health around both maxillary and mandibular teeth was extremely good. When attachment loss was assessed, 2238 of 2240 sites were clinically healthy. One patient, who had generally poor oral hygiene, had a 4-mm probing depth interproximally on the maxillary first and third molar contact. There was no correlation between periodontal health and mandibular third molar position. Therefore, both functional occlusion and periodontal health in the sample were good after loss of second permanent molars and eruption of the third molars.

  15. Bruxism (Teeth Grinding)

    MedlinePlus

    ... anger, frustration or tension Aggressive, competitive or hyperactive personality type Abnormal alignment of upper and lower teeth ( ... it usually goes away by the teen years. Personality type. Having a personality type that is aggressive, ...

  16. Teeth Injuries (For Parents)

    MedlinePlus

    ... Lessons? Visit KidsHealth in the Classroom What Other Parents Are Reading Your Child's Development (Birth to 3 Years) Feeding Your 1- to 3-Month-Old Feeding Your 4- to 7-Month-Old Feeding Your 8- to 12-Month-Old Feeding Your 1- to 2-Year-Old First Aid: Teeth Injuries ... Parents > First Aid: Teeth Injuries Print A A A ...

  17. Filament Eruption Onset

    NASA Technical Reports Server (NTRS)

    Sterling, Alphonse C.; Moore, Ronald L.

    2011-01-01

    We have been investigating filament eruptions in recent years. Use filament eruptions as markers of the coronal field evolution. Data from SoHO, Yohkoh, TRACE, Hinode, and other sources. We and others have observed: (1)Filaments often show slow rise, followed by fast rise, (2) Brightenings, preflares, microflares during slow rise (3) Magnetic evolution in hours prior to eruption onset. We investigated What do Hinode and SDO show for filament eruptions?

  18. An erupted compound odontoma.

    PubMed

    Gupta, Anil; Vij, Hitesh; Vij, Ruchieka; Malhotra, Ritika

    2014-04-12

    Odontomas are familiar entities but their eruption into the oral cavity is an extraordinary occurrence, which may be associated with pain, infection, malocclusion, etc. Not many cases of erupted odontomas have been reported in the literature. This paper puts forth a case of erupting odontoma in an attempt to add to the list of reported cases of this unique pathology.

  19. 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

  20. 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.

  1. 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.

  2. Teething disturbances; prevalence of objective manifestations in children under age 4 months to 36 months

    PubMed Central

    Basha, Sakeenabi

    2012-01-01

    Objective: The aim of this study was to present data as responded by parents on teething manifestation during eruption of primary teeth and the occurrence of objective manifestations in children ages 4 months to 36 months. Settings and Design: Hospital based face-to-face questionnaire study. Study Design: One thousand and one hundred children ages four to 36 months who had at least one erupting tooth were included in the study. Parents were asked to complete a short questionnaire and children were then checked by one of the authors. Statistical analysis used: Chi-square analysis was performed to analyze information obtained. Level of significance was set at P<.05. Results: There were 660 girls (60%) and 440 boys (40%) in the study. The most frequent clinical manifestations were: Fever (16%), drooling (12%), diarrhea (8%), fever-drooling (15%), fever-diarrhea(8%) and drooling-diarrhea (6%). In the study sample, boys demonstrated a higher prevalence of diarrhea than girls (P<.05). No statistical significance regarding other clinical manifestations and gender were observed. Teething manifestations were most prevalent during the eruption of primary incisors. Occurrence of clinical manifestations in 4-12months and 13-24 months age was statistically significant when compared with 25-36months age (P<0.05). Conclusions: An association has been shown between general objective manifestations like fever (the most prevalent), drooling and diarrhea, and the eruption of primary teeth. Most manifestations appeared during the eruption of the primary incisors. Key words:Teething, primary teeth, eruption. PMID:22143712

  3. Failure of tooth eruption in two patients with cerebral palsy and bruxism-a 10-year follow-up: a case report.

    PubMed

    Staufer, Kirsten; Hamadeh, Sinan; Gesch, Dietmar

    2009-01-01

    The aim of this paper was to analyze delayed tooth eruption in two children with cerebral palsy who had severe bruxism and to determine whether treatment could influence tooth eruption and alignment. Extraction of primary teeth was carried out and orthodontic treatment was considered due to severe tooth wear of primary teeth, lack of space, and development of a class III malocclusion. Analysis was based on clinical examination, photographs, radiographs, and dental casts. In both patients, early mixed dentition was delayed for more than 5 years. Calcification and root development of posterior permanent teeth corresponded with the chronological age. Root resorption of the severely abraded primary teeth and eruption of their successors were delayed or failed. Eruption of permanent teeth occurred slowly after primary teeth were extracted. Orthodontic treatment succeeded in one patient, achieving a normal overjet in combination with a successful orofacial therapy. The disturbed exfoliation of abraded primary teeth and failure of tooth eruption of the posterior teeth could be linked to the systemic pathology and to bruxism. At age 20, eruption of the canines and premolars remained questionable.

  4. 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

  5. Early prediction of eruption site using lightning location data: Estimates of accuracy during past eruptions

    NASA Astrophysics Data System (ADS)

    Nína Petersen, Guðrún; Arason, Þórður; Bjornsson, Halldór

    2013-04-01

    Eruption of subglacial volcanoes may lead to catastrophic floods and therefore early determination of the exact eruption site may be critical to civil protection evacuation plans. Poor visibility due to weather or darkness often inhibit positive identification of exact eruption location for many hours. However, because of the proximity and abundance of water in powerful subglacial volcanic eruptions, they are probably always accompanied by early lightning activity in the volcanic column. Lightning location systems, designed for weather thunderstorm monitoring, based on remote detection of electromagnetic waves from lightning, can provide valuable real-time information on location of eruption site. Important aspect of such remote detection is its independence of weather, apart from thunderstorms close to the volcano. Individual lightning strikes can be 5-10 km in length and are sometimes tilted and to the side of the volcanic column. This adds to the lightning location uncertainty, which is often a few km. Furthermore, the volcanic column may be swayed by the local wind to one side. Therefore, location of a single lightning can be misleading but by calculating average location of many lightning strikes and applying wind correction a more accurate eruption site location can be obtained. In an effort to assess the expected accuracy, the average lightning locations during the past five volcanic eruptions in Iceland (1998-2011) were compared to the exact site of the eruption vent. Simultaneous weather thunderstorms might have complicated this analysis, but there were no signs of ordinary thunderstorms in Iceland during these eruptions. To identify a suitable wind correction, the vector wind at the 500 hPa pressure level (5-6 km altitude) was compared to mean lightning locations during the eruptions. The essential elements of a system, which predicts the eruption site during the first hour(s) of an eruption, will be described.

  6. Tranexamic Acid-Induced Fixed Drug Eruption

    PubMed Central

    Matsumura, Natsuko; Hanami, Yuka; Yamamoto, Toshiyuki

    2015-01-01

    A 33-year-old male showed multiple pigmented patches on his trunk and extremities after he took tranexamic acid for common cold. He stated that similar eruptions appeared when he was treated with tranexamic acid for influenza 10 months before. Patch test showed positive results at 48 h and 72 h by 1% and 10% tranexamic acid at the lesional skin only. To our knowledge, nine cases of fixed drug eruption induced by tranexamic acid have been reported in Japan. Tranexamic acid is a safe drug and frequently used because of its anti-fibrinolytic and anti-inflammatory effects, but caution of inducing fixed drug eruption should be necessary. PMID:26288438

  7. Tranexamic Acid-Induced Fixed Drug Eruption.

    PubMed

    Matsumura, Natsuko; Hanami, Yuka; Yamamoto, Toshiyuki

    2015-01-01

    A 33-year-old male showed multiple pigmented patches on his trunk and extremities after he took tranexamic acid for common cold. He stated that similar eruptions appeared when he was treated with tranexamic acid for influenza 10 months before. Patch test showed positive results at 48 h and 72 h by 1% and 10% tranexamic acid at the lesional skin only. To our knowledge, nine cases of fixed drug eruption induced by tranexamic acid have been reported in Japan. Tranexamic acid is a safe drug and frequently used because of its anti-fibrinolytic and anti-inflammatory effects, but caution of inducing fixed drug eruption should be necessary.

  8. The 1991 eruption of Hekla, Iceland

    NASA Astrophysics Data System (ADS)

    Gudmundsson, Agust; Oskarsson, Niels; Gronvold, Karl; Saemundsson, Kristjan; Sigurdsson, Oddur; Stefansson, Ragnar; Gislason, Sigurdur R.; Einarsson, Pall; Brandsdottir, Bryndis; Larsen, Gudrun; Johannesson, Haukur; Thordarson, Thorvaldur

    1992-02-01

    The eruption that started in the Hekla volcano in South Iceland on 17 January 1991, and came to an end on 11 March, produced mainly andesitic lava. This lava covers 23 km2 and has an estimated volume of 0.15 km3. This is the third eruption in only 20 years, whereas the average repose period since 1104 is 55 years. Earthquakes, as well as a strain pulse recorded by borehole strainmeters, occurred less than half an hour before the start of the eruption. The initial plinian phase was very short-lived, producing a total of only 0.02 km3 of tephra. The eruption cloud attained 11.5 km in height in only 10 min, but it became detached from the volcano a few hours later. Several fissures were active during the first day of the eruption, including a part of the summit fissure. By the second day, however, the activity was already essentially limited to that segment of the principal fissure where the main crater subsequently formed. The average effusion rate during the first two days of the eruption was about 800 m3 s-1. After this peak, the effusion rate declined rapidly to 10 20 m3 s-1, then more slowly to 1 m3 s-1, and remained at 1 12 m3 s-1 until the end of the eruption. Site observations near the main crater suggest that the intensity of the volcanic tremor varied directly with the force of the eruption. A notable rise in the fluorine concentration of riverwater in the vicinity of the eruptive fissures occurred on the 5th day of the eruption, but it levelled off on the 6th day and then remained essentially constant. The volume and initial silica content of the lava and tephra, the explosivity and effusion rate during the earliest stage of the eruption, as well as the magnitude attained by the associated earthquakes, support earlier suggestions that these parameters are positively related to the length of the preceeding repose period. The chemical difference between the eruptive material of Hekla itself and the lavas erupted in its vicinity can be explained in terms of a

  9. About Kids' Teeth

    MedlinePlus

    ... of your baby getting the bacteria that cause tooth decay. Make sure you take good care of your baby’s teeth – this reduces the number of bacteria in your baby’s mouth. Decay Prevention Tips Don’t share saliva with your baby ...

  10. Congenital adrenal hyperplasia: a case report with premature teeth exfoliation and bone resorption.

    PubMed

    Angelopoulou, Matina V; Kontogiorgos, Elias; Emmanouil, Dimitris

    2015-06-01

    Congenital adrenal hyperplasia (CAH) is an inherited autosomal recessive disorder characterized by insufficient production of cortisol. The aim of this case report was to present a child with CAH, premature exfoliation of primary teeth and accelerated eruption of his permanent teeth related to bone resorption. A 4.5-year-old Caucasian boy with CAH and long-term administration of glucocorticoids was referred for dental restoration. Clinical examination revealed primary molars with worn stainless steel crowns, severe attrition of the upper canines, and absence of the upper incisors. Before the completion of treatment, abnormal mobility of the first upper primary molars and the lower incisors was detected, and a few days later the teeth exfoliated prematurely. Histologic examination revealed normal tooth structure. Alkaline phosphatase and blood cells values were normal. Eruption of the permanent dentition was also accelerated. Tooth mobility was noticed in the permanent teeth as soon as they erupted, along with bone destruction. Examination revealed an elevated level of receptor activator of nuclear factor-κB ligand and lower-than-normal osteoprotegerin and vitamin D levels. The patient was treated with vitamin D supplements, and his teeth have been stable ever since. CAH is a serious chronic disorder appearing in children with accelerated dental development and possibly premature loss of primary teeth.

  11. Positioning.

    ERIC Educational Resources Information Center

    Conone, Ruth M.

    The key to positioning is the creation of a clear benefit image in the consumer's mind. One positioning strategy is creating in the prospect's mind a position that takes into consideration the company's or agency's strengths and weaknesses as well as those of its competitors. Another strategy is to gain entry into a position ladder owned by…

  12. Something to sink your teeth into: The presence of teeth augments ERPs to mouth expressions.

    PubMed

    daSilva, Elizabeth B; Crager, Kirsten; Geisler, Danika; Newbern, Powell; Orem, Benjamin; Puce, Aina

    2016-02-15

    If the whites of the sclera can impact neural processing of eye expressions (Hardee, Thompson, & Puce, 2008; Whalen et al., 1998), do seen teeth affect neural responses to mouth expressions? Twenty participants (10 females; ages 22-31) viewed avatar mouth images depicting grimaces, smiles and open mouth expressions that were presented with and without teeth. A continuous 256 channel electroencephalogram (EEG) was recorded while subjects completed two tasks: an implicit task evaluating stimulus color and an explicit task evaluating mouth expression valence. Event related potential (ERP) peak amplitudes and latencies and area under the curve (AUC) were measured in individual subject averaged ERPs. Statistical testing revealed a main effect of the presence of Teeth for P100, N170, and vertex positive potential (VPP) amplitudes and for slow positive wave (SPW) AUC. Task by teeth interactions occurred for P250 amplitude, underscoring how explicit task demands can influence neural processing. Arousal ratings co-varied with teeth presence, suggesting that low-level visual features such as teeth may drive the saliency of emotional expressions, and lie at the core of differences in neural processing to different emotional expressions.

  13. Taking Care of Your Teeth

    MedlinePlus

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

  14. Mouth and Teeth (For Parents)

    MedlinePlus

    ... infection, a dentist might need to remove them. Human teeth are made up of four different types of ... previous continue Normal Development of the Mouth and Teeth Humans are diphyodont, meaning that they develop two sets ...

  15. 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.

  16. Topological Analyses of Symmetric Eruptive Prominences

    NASA Astrophysics Data System (ADS)

    Panasenco, O.; Martin, S. F.

    Erupting prominences (filaments) that we have analyzed from Hα Doppler data at Helio Research and from SOHO/EIT 304 Å, show strong coherency between their chirality, the direction of the vertical and lateral motions of the top of the prominences, and the directions of twisting of their legs. These coherent properties in erupting prominences occur in two patterns of opposite helicity; they constitute a form of dynamic chirality called the ``roll effect." Viewed from the positive network side as they erupt, many symmetrically-erupting dextral prominences develop rolling motion toward the observer along with right-hand helicity in the left leg and left-hand helicity in the right leg. Many symmetricaly-erupting sinistral prominences, also viewed from the positive network field side, have the opposite pattern: rolling motion at the top away from the observer, left-hand helical twist in the left leg, and right-hand twist in the right leg. We have analysed the motions seen in the famous movie of the ``Grand Daddy" erupting prominence and found that it has all the motions that define the roll effect. From our analyses of this and other symmetric erupting prominences, we show that the roll effect is an alternative to the popular hypothetical configuration of an eruptive prominence as a twisted flux rope or flux tube. Instead we find that a simple flat ribbon can be bent such that it reproduces nearly all of the observed forms. The flat ribbon is the most logical beginning topology because observed prominence spines already have this topology prior to eruption and an initial long magnetic ribbon with parallel, non-twisted threads, as a basic form, can be bent into many more and different geometrical forms than a flux rope.

  17. An Eruption on Io

    NASA Technical Reports Server (NTRS)

    2007-01-01

    The first images returned to Earth by New Horizons during its close encounter with Jupiter feature the Galilean moon Io, snapped with the Long Range Reconnaissance Imager (LORRI) at 0840 UTC on February 26, while the moon was 2.5 million miles (4 million kilometers) from the spacecraft.

    Io is intensely heated by its tidal interaction with Jupiter and is thus extremely volcanically active. That activity is evident in these images, which reveal an enormous dust plume, more than 150 miles high, erupting from the volcano Tvashtar. The plume appears as an umbrella-shaped feature of the edge of Io's disk in the 11 o'clock position in the right image, which is a long-exposure (20-millisecond) frame designed specifically to look for plumes like this. The bright spots at 2 o'clock are high mountains catching the setting sun; beyond them the night side of Io can be seen, faintly illuminated by light reflected from Jupiter itself.

    The left image is a shorter exposure -- 3 milliseconds -- designed to look at surface features. In this frame, the Tvashtar volcano shows as a dark spot, also at 11 o'clock, surrounded by a large dark ring, where an area larger than Texas has been covered by fallout from the giant eruption.

    This is the clearest view yet of a plume from Tvashtar, one of Io's most active volcanoes. Ground-based telescopes and the Galileo Jupiter orbiter first spotted volcanic heat radiation from Tvashtar in November 1999, and the Cassini spacecraft saw a large plume when it flew past Jupiter in December 2000. The Keck telescope in Hawaii picked up renewed heat radiation from Tvashtar in spring 2006, and just two weeks ago the Hubble Space Telescope saw the Tvashtar plume in ultraviolet images designed to support the New Horizons flyby.

    Most of those images will be stored onboard the spacecraft for downlink to Earth in March and April.

  18. [Clinical anatomy of the horse: teeth and dentition].

    PubMed

    Staszyk, C

    2015-01-01

    The routine inspection of the equine oral cavity allows a numerical assessment of the teeth and provides information about positional changes within the dentition. By use of appropriate dental equipment, the occlusal surfaces of all teeth can be inspected and diagnosed. However, neither the teeth nor their occlusal surfaces are constant structures. Instead, equine teeth and, in particular, their occlusal surfaces are subjected to continuous morphological and positional changes due to the effects of aging and the equine-specific high amount of occlusal wear. Therefore, it is mandatory to define anatomical criteria, which allow us to distinguish between anatomical variations and pathological conditions. Moreover, an unambiguous nomenclature with regard to the equine-specific dental anatomy is essential. This article provides a tutorial overview of the equine dental anatomy as well as recent findings in the field of equine dentistry. Special attention is paid to dynamic changes within both individual teeth and dentition.

  19. Remarkable resilience of teeth

    PubMed Central

    Chai, Herzl; Lee, James J.-W.; Constantino, Paul J.; Lucas, Peter W.; Lawn, Brian R.

    2009-01-01

    Tooth enamel is inherently weak, with fracture toughness comparable with glass, yet it is remarkably resilient, surviving millions of functional contacts over a lifetime. We propose a microstructural mechanism of damage resistance, based on observations from ex situ loading of human and sea otter molars (teeth with strikingly similar structural features). Section views of the enamel implicate tufts, hypomineralized crack-like defects at the enamel–dentin junction, as primary fracture sources. We report a stabilization in the evolution of these defects, by “stress shielding” from neighbors, by inhibition of ensuing crack extension from prism interweaving (decussation), and by self-healing. These factors, coupled with the capacity of the tooth configuration to limit the generation of tensile stresses in largely compressive biting, explain how teeth may absorb considerable damage over time without catastrophic failure, an outcome with strong implications concerning the adaptation of animal species to diet. PMID:19365079

  20. Linear drug eruption.

    PubMed

    Alfonso, R; Belinchon, I

    2001-01-01

    Linear eruptions are sometimes associated with systemic diseases and they may also be induced by various drugs. Paradoxically, such acquired inflammatory skin diseases tend to follow the system of Blaschko's lines. We describe a case of unilateral linear drug eruption caused by ibuprofen, which later became bilateral and generalized.

  1. Generalized Eruptive Syringoma

    PubMed Central

    Avhad, Ganesh; Ghuge, Priyanka; Jerajani, HR

    2015-01-01

    Eruptive syringoma is a very rare variant of syringoma. It is a benign adnexal tumor of the intraepidermal portion of eccrine sweat ducts. Here we report a 32-year-old female presented with classical asymptomatic eruptive syringomas involving her face and extremities. PMID:25814740

  2. Initiation of Solar Eruptions

    NASA Technical Reports Server (NTRS)

    Sterling, Alphonse C.; Moore, Ronald L.

    2007-01-01

    We consider processes occurring just prior to and at the start of the onset of flare- and CME-producing solar eruptions. Our recent work uses observations of filament motions around the time of eruption onset as a proxy for the evolution of the fields involved in the eruption. Frequently the filaments show a slow rise prior to fast eruption, indicative of a slow expansion of the field that is about co explode. Work by us and others suggests that reconnection involving emerging or canceling flux results in a lengthening of fields restraining the filament-carrying field, and the consequent upward expansion of the field in and around the filament produces the filament's slow rise: that is, the reconnection weakens the magnetic "tethers" ("tether-weakening" reconnection), and results in the slow rise of the filament. It is still inconclusive, however, what mechanism is responsible for the switch from the slow rise to the fast eruption.

  3. Fluconazole-induced Fixed Drug Eruption.

    PubMed

    Gaiser, Cory Allen; Sabatino, Dominick

    2013-03-01

    Triazole antifungals are commonly used in the treatment of oral, esophageal, and vaginal candidiasis. Fluconazole is frequently prescribed as the therapy modality for vaginal fungal infections. On rare occasions, fluconazole has been shown to cause fixed drug eruptions. Lesions of fixed drug eruptions vary in size and number, but have the same general appearance and symptoms. The authors report a case of fluconazole-induced fixed drug eruption in a 24-year-old woman with recurrent vaginal candidiasis. The lesion was initially diagnosed as a spider bite. Topical and oral provocation tests with fluconazole were performed. Topical provocation with petroleum/fluconazole and dimethyl sulfoxide/fluonazole were both negative. Oral provocation was positive, thus confirming the diagnosis of fluconazole-induced fixed drug eruption.

  4. 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

  5. New teeth from old: treatment options for retained primary teeth.

    PubMed

    Robinson, S; Chan, M F W-Y

    2009-10-10

    Retention of primary teeth beyond their expected exfoliation date is encountered relatively frequently. Most commonly this is due to absence of the permanent successor. In this article patient assessment and the restorative treatment options are discussed with particular emphasis on retention of the primary tooth/teeth in the medium to long-term. The restorative techniques that may be used to improve aesthetics and function of retained primary teeth are illustrated. Consideration of this minimally invasive approach is commended in such cases.

  6. 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.

  7. Immediate loading of an implant following implant site development using forced eruption: a case report.

    PubMed

    Park, Young-Seok; Yi, Ki-Young; Moon, Seong-Cheol; Jung, Young-Chul

    2005-01-01

    In restoring periodontally involved hopeless teeth, implant treatment has been widely used with combinations of various grafting techniques or guided bone regeneration. Instead of traditional surgical procedures, forced tooth eruption may be used successfully for implant site development. In this case, the authors orthodontically erupted a hopeless central incisor with an angular bony defect. Subsequently, they placed an implant immediately after tooth extraction and immediately loaded it with a temporary resin restoration.

  8. Use of forced eruption to enhance a pontic site in the anterior maxilla.

    PubMed

    Comut, Alper; Acharya, Varun; Jahangiri, Leila

    2012-11-01

    Extraction of teeth leads to bone resorption that can result in asymmetrical hard and soft tissue topography. This article describes a technique to enhance a pontic site in the anterior maxilla by using forced eruption as an alternative to conventional hard and soft tissue augmentation surgeries. Forced eruption is a well-known procedure and its use in developing a pontic site for a fixed dental prosthesis is described in this clinical report.

  9. Dental fluorosis prevalence and severity using Dean's index based on six teeth and on 28 teeth.

    PubMed

    Medina-Solis, Carlo Eduardo; Pontigo-Loyola, América Patricia; Maupome, Gerardo; Lamadrid-Figueroa, Hector; Loyola-Rodríguez, Juan Pablo; Hernández-Romano, Jesús; Villalobos-Rodelo, Juan José; de Lourdes Marquez-Corona, Ma

    2008-09-01

    To contrast the sensitivity, specificity, and positive-negative predictive values between dental fluorosis prevalence scored on 28 (DF28) and on six permanent teeth (DF6), we undertook a cross-sectional study on 1,538 adolescents (12 and 15 years old) residing in Hidalgo State, Mexico, a naturally fluoridated (>0.7 ppm) area at an elevated altitude (>2,500 m above sea level). Dental fluorosis was scored using Deans modified index. Using the scores obtained for all teeth present (DF28) as a gold standard, we calculated the sensitivity, specificity, positive-negative predictive values, and receiver operating characteristic and concordance index pertaining to the scores based on six teeth (upper incisors and canines). DF28 fluorosis prevalence was 81.7%; based on DF6, it was 58.7% (23% difference). Among 12 year olds, the difference between DF28 and DF6 was 20.1% (84.5 vs. 64.4%); among 15 year olds, it was 25.4% (79.4 vs. 54%). Among girls, it was 23.2% (81.1 vs. 57.9%) and among boys, 22.8% (82.2 vs. 59.4%). The fluorosis community indices were 1.75 (DF28) and 1.11 (DF6). All positive predictive values reached 100% while negative predictive values were below 45%. Concordance between DF28 and DF6 was 53.9%, and kappa coefficient was 0.40. Partial scoring of fluorosis based on esthetically important permanent teeth underestimated prevalence, compared to full-mouth scoring. The decision to use an abridged Dean's index protocol must take into account the number of teeth examined, and which specific teeth are examined, to appraise the benefit of reduced data collection effort against possible information loss.

  10. 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.

  11. Snake Filament Eruption

    NASA Video Gallery

    A very long solar filament that had been snaking around the Sun erupted on Dec. 6, 2010 with a flourish. NASA's Solar Dynamics Observatory (SDO) caught the action in dramatic detail in extreme ultr...

  12. Triple Solar Eruption

    NASA Video Gallery

    Solar activity surged on the morning of Dec 12, 2010 when the sun erupted three times in quick succession, hurling a trio of bright coronal mass ejections (CMEs) into space. Coronagraphs onboard th...

  13. Erupting Volcano Mount Etna

    NASA Technical Reports Server (NTRS)

    2001-01-01

    An Expedition Two crewmember aboard the International Space Station (ISS) captured this overhead look at the smoke and ash regurgitated from the erupting volcano Mt. Etna on the island of Sicily, Italy. At an elevation of 10,990 feet (3,350 m), the summit of the Mt. Etna volcano, one of the most active and most studied volcanoes in the world, has been active for a half-million years and has erupted hundreds of times in recorded history.

  14. An erupted complex odontoma.

    PubMed

    Tozoglu, Sinan; Yildirim, Umran; Buyukkurt, M Cemil

    2010-01-01

    Odontomas are benign tumors of odontogenic origin. The cause of the odontoma is unknown, but it is believed to be hereditary or due to a disturbance in tooth development triggered by trauma or infection. Odontomas may be either compound or complex. Although these tumors are seen frequently, erupted odontomas are rare. The purpose of this study is to present a rare case of complex odontoma that erupted into the oral cavity.

  15. Tricho-dento-osseous syndrome and precocious eruption.

    PubMed

    Jain, Parul; Kaul, Rahul; Saha, Subrata; Sarkar, Subir

    2017-03-01

    Tricho-dento-osseous syndrome (TDO), an uncommon form of ectodermal dysplasia is an autosomal dominant genetic disorder which is characterized by inherited defects in tissues arising from epithelial-mesenchymal interaction. Genetic studies have revealed that it is caused by mutation in the DLX3 gene. TDO presents with a great phenotypic heterogeneity and studies have suggested that this heterogeneity is the result of environmental factors or other genetic modifiers. In this article, we report a case of TDO in which the child had typical clinical features of hair, teeth and bone defects, as seen in TDO. Parents of the child were unaffected. Genetic analysis of the child revealed mutation in DLX3 gene. The child also showed precocious eruption of the permanent molars, a clinical feature which has been rarely reported. We suggest that the precocious eruption seen in TDO is probably due to a markedly increased osteoblastic activity. Key words:Tricho-dento-osseous syndrome, DLX3 gene, precocious eruption.

  16. 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.

  17. Primary tooth radicular resorption as a consequence of self-corrected ectopic eruption: 2 unusual cases.

    PubMed

    Guzeler, Irem; Sara, Sezgi; Cehreli, Zafer C; Uysal, Serdar; Musselman, Robert J

    2011-01-01

    Resorption of the distal root of primary second molars is a common consequence of ectopically erupting permanent first molars. Here, we report 2 unusual cases of primary molar root resorption caused by reversible (self-correcting) ectopic eruption of premolar and canine teeth. In both cases, severe pathological resorption of the mesial roots of primary molars was detected on routine dental radiographs, and the affected molars remained asymptomatic until exfoliation. The purpose of this paper was, using 2 case studies, to highlight the possibility of primary root resorption as a sequel of self-corrected ectopic eruption in locations not frequently diagnosed or reported.

  18. 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)

  19. Multidisciplinary approach to traumatized teeth: a case report.

    PubMed

    Yüzügüllü, Bulem; Polat, Omür; Ungör, Mete

    2008-10-01

    Treatment of crown fractures often requires a multidisciplinary approach. In the anterior teeth, reestablishment of proper esthetics and function is quite important for the patient. However, crown-root fractures with fracture line below the gingival attachment or alveolar bone crest presents restorative difficulties. This case report presents a cervical tooth fracture that had been treated with minimal invasive approach with different disciplines. The tooth had endodontic treatment and a glass-fiber post, and a composite core was accomplished. Then, the tooth was extruded to the desired level with orthodontic forced eruption before definitive restoration.

  20. 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.

  1. Bilateral distal ectopic eruption of the permanent mandibular central incisors: a case report.

    PubMed

    Portela, Maristela Barbosa; Sanchez, Ana Lúcia Freire; Gleiser, Rogério

    2003-02-01

    A 7-year-old female patient presented with a rare case of bilateral distal ectopic eruption of the mandibular permanent central incisors. Treatment instituted was extraction of the retained primary teeth and placement of a fixed appliance for alignment and repositioning of the mandibular permanent incisors.

  2. 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.

  3. Erupting Volcano Mount Etna

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Expedition Five crew members aboard the International Space Station (ISS) captured this overhead look at the smoke and ash regurgitated from the erupting volcano Mt. Etna on the island of Sicily, Italy in October 2002. Triggered by a series of earthquakes on October 27, 2002, this eruption was one of Etna's most vigorous in years. This image shows the ash plume curving out toward the horizon. The lighter-colored plumes down slope and north of the summit seen in this frame are produced by forest fires set by flowing lava. At an elevation of 10,990 feet (3,350 m), the summit of the Mt. Etna volcano, one of the most active and most studied volcanoes in the world, has been active for a half-million years and has erupted hundreds of times in recorded history.

  4. Seasonality of Volcanic Eruptions

    NASA Astrophysics Data System (ADS)

    Mason, B.; Pyle, D. M.; Dade, W. B.; Jupp, T.

    2001-12-01

    An analysis of volcanic activity in the last three hundred years reveals that the frequency of onset of volcanic eruptions varies systematically with the time of year. We analysed the Smithsonian catalogue of more than 3200 subaerial eruptions recorded during the last 300 years. We also investigated continuous records, which are not part of the general catalogue, of individual explosions at Sakurajima volcano (Japan, 150 events per year since 1955) and Semeru (Indonesia, 100,000 events during the period 1997-2000). A higher proportion (as much as 18 percent of the average monthly rate) of eruptions occur worldwide between December and March. This observation is statistically significant at above the 99 percent level. This pattern is independent of the time interval considered, and emerges whether individual eruptions are counted with equal weight or with weights proportional to event explosivity. Elevated rates of eruption onset in boreal winter months are observed in northern and southern hemispheres alike, as well as in most volcanically-active regions including, most prominently, the 'Ring of Fire' surrounding the Pacific basin. Key contributors to this regional pattern include volcanoes in Central and South America, the volcanic provinces of the northwest Pacific rim, Indonesia and the southwest Pacific basin. On the smallest spatial scales, some individual volcanoes for which detailed histories exist exhibit peak levels in eruption activity during November-January. Seasonality is attributed to one or more mechanisms associated with the annual hydrological cycle, and may correspond to the smallest time-scale over which fluctuations in stress due to the redistribution of water-masses are felt by the Earth's crust. Our findings have important ramifications for volcanic risk assessment, and offer new insight into possible changes in volcanic activity during periods of long-term changes in global sea level.

  5. Seasonality of volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Mason, B.; Pyle, D.; Dade, B.; Jupp, T.

    2003-04-01

    An analysis of volcanic activity in the last three hundred years reveals that the frequency of onset of volcanic eruptions varies systematically with the time of year. We analysed the Smithsonian catalogue of more than 3200 subaerial eruptions recorded during the last 300 years. We also investigated continuous records, which are not part of the general catalogue, of individual explosions at Sakurajima volcano (Japan, 150 events per year since 1955) and Semeru (Indonesia, 100,000 events during the period 1997-2000). A higher proportion (as much as 18 percent of the average monthly rate) of eruptions occur worldwide between December and March. This observation is statistically significant at above the 99 percent level. This pattern is independent of the time interval considered, and emerges whether individual eruptions are counted with equal weight or with weights proportional to event explosivity. Elevated rates of eruption onset in boreal winter months are observed in northern and southern hemispheres alike, as well as in most volcanically-active regions including, most prominently, the 'Ring of Fire' surrounding the Pacific basin. Key contributors to this regional pattern include volcanoes in Central and South America, the volcanic provinces of the northwest Pacific rim, Indonesia and the southwest Pacific basin. On the smallest spatial scales, some individual volcanoes for which detailed histories exist exhibit peak levels in eruption activity during November-January. Seasonality is attributed to one or more mechanisms associated with the annual hydrological cycle, and may correspond to the smallest time-scale over which fluctuations in stress due to the redistribution of water-masses are felt by the Earth's crust. Our findings have important ramifications for volcanic risk assessment, and offer new insight into possible changes in volcanic activity during periods of long-term changes in global sea level.

  6. Botulinum neurotoxin type A in the masseter muscle: Effects on incisor eruption in rabbits

    PubMed Central

    Navarrete, Alfonso L.; Rafferty, Katherine L.; Liu, Zi Jun; Ye, Wenmin; Greenlee, Geoffrey M.; Herring, Susan W.

    2015-01-01

    Introduction Botulinum neurotoxins are responsible for the paralytic food poisoning, botulism. Commercial formulations such as botulinum neurotoxin type A are increasingly used for various conditions, including cosmetic recontouring of the lower face by injection of the large masseter muscles. The paralysis of a major muscle of mastication lowers occlusal force and thus might affect tooth eruption. The purpose of this study was to investigate the effects of unilateral masseter muscle injection of botulinum neurotoxin type A on the rate of eruption of incisors in a rabbit model. We hypothesized that the teeth would overerupt in an underloaded environment. Methods Forty rabbits were injected with either botulinum neurotoxin type A or saline solution in 1 masseter muscle. Mastication and muscle force production were monitored, and incisor eruption rate was assessed by caliper measurement of grooved teeth. Results The injection of saline solution had no effect. The masseter muscle injected with botulinum neurotoxin type A showed a dramatic loss of force 3 weeks after injection despite apparently normal mastication. Incisor eruption rate was significantly decreased for the botulinum neurotoxin type A group, an effect attributed to decreased attrition. Conclusions This study has implications for orthodontics. Although findings from ever-growing rabbit incisors cannot be extrapolated to human teeth, it is clear that botulinum neurotoxin type A caused a decrease in bite force that could influence dental eruption. PMID:23561411

  7. 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

  8. 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

  9. Delayed Replantation of Avulsed Teeth: Two Case Reports

    PubMed Central

    Savas, Selcuk; Kucukyilmaz, Ebru; Akcay, Merve; Koseoglu, Serhat

    2015-01-01

    This case report presents two cases of delayed replantation of avulsed maxillary central incisors after an extended dry extra-alveolar period. Eight-year-old boy and 10-year-old boy presented with avulsed maxillary central incisors due to trauma occurring 27 and 7 hours earlier, respectively. Treatment guidelines for avulsed mature/immature permanent teeth with prolonged extra-oral time were carried out for the teeth and the extra-oral endodontic treatment was completed. After having been repositioned, the teeth were stabilized for 4 weeks and prophylactic antibiotic was prescribed. Clinical and radiographic controls were done after 18 months for Case I and 12 months for Case II. During the follow-up periods the teeth reported in these cases have remained in a stable, functional position but revealed clinical initial replacement resorption and ankylosis. PMID:25810928

  10. 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)

  11. Kimberlite ascent and eruption.

    PubMed

    Sparks, R S J; Brown, R J; Field, M; Gilbertson, M

    2007-12-13

    Wilson and Head model kimberlite ascent and eruption by considering the propagation of a volatile-rich dyke. Wilson and Head's model has features in common with Sparks et al., but it is inconsistent with geological observations and constraints on volatile solubility. Here we show that this may be due to erroneous physical assumptions.

  12. 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.

  13. Eruption of Pele

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The eruption of Pele on Jupiter's moon Io. The volcanic plume rises 300 kilometers above the surface in an umbrella-like shape. The plume fallout covers an area the size of Alaska. The vent is a dark spot just north of the triangular-shaped plateau (right center). To the left, the surface is covered by colorful lava flows rich in sulfur.

  14. 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.

  15. Reunion Island Volcano Erupts

    NASA Technical Reports Server (NTRS)

    2002-01-01

    On January 16, 2002, lava that had begun flowing on January 5 from the Piton de la Fournaise volcano on the French island of Reunion abruptly decreased, marking the end of the volcano's most recent eruption. These false color MODIS images of Reunion, located off the southeastern coast of Madagascar in the Indian Ocean, were captured on the last day of the eruption (top) and two days later (bottom). The volcano itself is located on the southeast side of the island and is dark brown compared to the surrounding green vegetation. Beneath clouds (light blue) and smoke, MODIS detected the hot lava pouring down the volcano's flanks into the Indian Ocean. The heat, detected by MODIS at 2.1 um, has been colored red in the January 16 image, and is absent from the lower image, taken two days later on January 18, suggesting the lava had cooled considerably even in that short time. Earthquake activity on the northeast flank continued even after the eruption had stopped, but by January 21 had dropped to a sufficiently low enough level that the 24-hour surveillance by the local observatory was suspended. Reunion is essentially all volcano, with the northwest portion of the island built on the remains of an extinct volcano, and the southeast half built on the basaltic shield of 8,630-foot Piton de la Fournaise. A basaltic shield volcano is one with a broad, gentle slope built by the eruption of fluid basalt lava. Basalt lava flows easily across the ground remaining hot and fluid for long distances, and so they often result in enormous, low-angle cones. The Piton de la Fournaise is one of Earth's most active volcanoes, erupting over 150 times in the last few hundred years, and it has been the subject of NASA research because of its likeness to the volcanoes of Mars. Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC

  16. 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.

  17. Eruption cysts: A series of 66 cases with clinical features

    PubMed Central

    Şen-Tunç, Emine; Şaroğlu-Sönmez, Işıl; Bayrak, Şule; Tüloğlu, Nuray

    2017-01-01

    Background An eruption cyst (EC) is a benign, developmental cyst associated with a primary or permanent tooth. This paper presents 66 ECs in 53 patients who reported to 3 different centers in Turkey between 2014-2015. Material and Methods 53 patients (31 male, 22 female) with 66 ECs were diagnosed and treated over a 1-year period. The mean age of patients was 5.4 years (minimum 5 months, maximum 11 years). Clinical examination and periapical radiographs were used to establish diagnosis. Age, gender, site, history of trauma and type of treatment were recorded. Results Of the 66 ECs diagnosed in 53 patients, more than half (56.6%) were located in the maxilla, with the maxillary first primary molars the teeth most commonly associated with ECs (30.3%). Multiple ECs were diagnosed in 13 of the 53 patients. ECs had previously diagnosed in the primary dentition of 2 patients, 3 patients reported a history of trauma to primary teeth. In the majority of patients (46 cases, 86.8%), no treatment was provided, whereas surgical treatment was provided in the remaining 7 cases (13.2%). Conclusions Eruption cysts are usually asymptomatic and do not require treatment;. however, if the cyst is symptomatic, it should be treated with simple surgical excision. Key words:Odontogenic cyst, children, eruption cyst, oral pathology. PMID:28160586

  18. ClC-7 Deficiency Impairs Tooth Development and Eruption

    PubMed Central

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

    2016-01-01

    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. PMID:26829236

  19. Current aspects of restoring traumatically fractured teeth.

    PubMed

    Krastl, Gabriel; Filippi, Andreas; Zitzmann, Nicola U; Walter, Clemens; Weiger, Roland

    2011-01-01

    Endodontic and restorative considerations are of primary significance in the treatment of tooth fractures. Since exposed dentinal tubules permit invasion of bacteria into the endodontic system, a protective dressing must be applied as part of the emergency treatment. Provided the dentin wound has been sealed, restorative treatment can also be carried out at a later stage. The fractured tooth fragment can be reattached using adhesive protocols in order to restore function and esthetic appearance. If reattachment is difficult or impossible, eg, in cases of multiple or missing fragments, current composite materials enable excellent esthetic results. Minimally-invasive direct composite restorations are preferred over the more invasive indirect restorations, at least in immature teeth with an extensive coronal pulp dimension. Restorative treatment of crown-root fractures is frequently demanding due to inaccessible subgingival fracture margins. Extrusion of the remaining root is an alternative method to surgical crown lengthening for re-establishing the biological width. This can be carried out either orthodontically (forced eruption), or surgically (intra-alveolar transplantation). Although the treatment of crown-root fractures is one of the most technically sensitive procedures in dental traumatology and is frequently considered as a long-term temporary restoration, tooth conservation up to the age at which implants can be placed may be regarded as a success.

  20. Lightning During the Eruptions at Sakurajima Volcano, Japan

    NASA Astrophysics Data System (ADS)

    Thomas, R. J.; Behnke, S. A.; Edens, H. E.; Iguchi, M.; Miki, D.; McNutt, S. R.; Van Eaton, A. R.; Smith, C. M.; Cimarelli, C.; Cigala, V.

    2015-12-01

    In May 2015 our volcano-lightning team spent about 2 weeks at the Sakurajima volcano observing electrical activity during many explosive eruptions. The explosive eruptions sent ash into the atmosphere reaching between 2 and 5 km MSL. Most of the eruptions produced lightning and electrical activity. Our measurements included electric, photographic, seismic, and ascustic. The atmospheric-electricity instruments included a 10-station-LMA, slow antenna, fast antenna, and broad-band-RF. Inaddition to standard photography and video, we had infrared video, low-light video, and high-speed video. The slow antenna showed that typically the predominant charge was negative, but at times it was positive. The larger eruptions show the continual electrical discharges that begin coincident within tenths of a second as the explosion. We have sensed these small discharges in many other volcanic eruptions.

  1. Measurements of Lightning During the Grimsvotn 2004 Eruption in Iceland

    NASA Astrophysics Data System (ADS)

    Arason, P.

    2009-05-01

    Lightning activity in volcanic ash plumes is common, especially in subglacial or submarine eruptions. The interaction between magma and water may be responsible for electric charge separation, leading to positively charged vapor and negatively charged ash. Lightning data were collected during the last three volcanic eruptions in Iceland; Grimsvotn 1998, Hekla 2000 and Grimsvotn 2004. For the last eruption we collected data from the LLP Icelandic lightning location system, the ATD sferics system of the UK Met Office, as well as from our vertical E-field wave recording station, located in Reykjavik. We note a good correlation between the lightning activity and the intensity of the eruptions as indicated by the height of the ash plume observed by weather radar. The lightning data collected during these volcanic eruptions gives valuable insight into the character of volcanogenic lightning and how they differ from weather lightning.

  2. 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

  3. Occlusal angles of cheek teeth in normal horses and horses with dental disease.

    PubMed

    Brown, S L; Arkins, S; Shaw, D J; Dixon, P M

    2008-06-21

    The angle between the occlusal surface of the tooth and the horizontal plane of 687 cheek teeth from the skulls of 22 horses without gross dental disorders and 11 horses with dental disorders were measured by using stiff malleable wire as an imprint. Each measurement was repeated five times and the mean angle was recorded. In the normal skulls, the mean occlusal angles of the mandibular cheek teeth ranged from 19.2 degrees at the Triadan 06 position to 30 degrees at the 11 position, and these angles were significantly greater than the occlusal angles of the opposing maxillary cheek teeth (range 12.5 degrees to 18 degrees) at all the positions except the 06. The rostral mandibular cheek teeth had significantly lower occlusal angles than the caudal mandibular cheek teeth, but the converse was true for the maxillary teeth. In the skulls with dental disorders the occlusal angles of the mandibular cheek teeth ranged from 15.6 degrees to 28.5 degrees , and of the maxillary cheek teeth from 9.2 degrees to 16.4 degrees. They were not significantly different from the angles of the teeth from the normal skulls, except at the 06 position, where they were smaller.

  4. Modelling VLP sources for the 25 September 2007 Ruapehu eruption

    NASA Astrophysics Data System (ADS)

    Jolly, A. D.; Jousset, P.; Sherburn, S.

    2008-12-01

    Mt. Ruapehu erupted on 25 September 2007 at 20:26 PM NZDT (8:26 UT) generating a moderate steam column to about 15,000 feet, a directed ballistic and surge deposit of coarse blocks and ash to the north of the Crater Lake, and initiated lahars in the Whangaehu catchment and Whakapapa ski field. The eruption was recorded on three broadband seismometers and two acoustic pressure sensors which indicated broadly coherent waveform characteristics across the network. The eruption had duration of less than 1 minute as indicated by strong seismic and acoustic pulses. The acoustic wave coincided with observed very long period (VLP) seismic signal (7-25 s period with 13 s peak). The acoustic pulse had positive pressure (indicating an explosion) and travelled at a velocity of ~320 m/s. The associated VLP ground displacement (elastic velocity ~2500 m/s) changed from negative (compression) to positive (dilatation) at the onset of the eruption. The syn-eruptive VLP was composed of surface waves having strong radial and transverse components which varied dependent on station azimuth and distance. The immediate aftermath of the eruption produced about 3 minutes of continued high amplitude spasmodic tremor signals that probably resulted from post-explosion phase associated vent backfill/stabilisation. The eruption was preceded by minor volcano-tectonic earthquakes and tremor pulses which began 10 minutes before the main eruption. Two smaller VLP pulses were associated with these tremor pulses at 20:16 and 20:25. These pre-eruptive VLP pulses had particle motions indicating body waves from a subsurface source region less than 4 km below the surface. We are modelling pre-eruption and eruption VLP pulses using a three-dimensional finite-difference scheme which incorporates topography. Data (from three broadband stations) are insufficient to determine uniquely constrained source processes. However the data are sufficient to test specific pre and syn-eruption source models. We aim to

  5. 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.

  6. Vascular endothelial growth factor receptor-2 expression in the pulp of human primary and young permanent teeth.

    PubMed

    Grando Mattuella, Leticia; Poli de Figueiredo, José Antonio; Nör, Jacques E; de Araujo, Fernando Borba; Medeiros Fossati, Anna Christina

    2007-12-01

    The purpose of this study was to evaluate the expression of vascular endothelial growth factor receptor-2 (VEGFR-2) in endothelial cells within the dental pulp of human primary and young permanent teeth and the spatial distribution of VEGFR-2-positive cells. Nine sound primary teeth and 4 sound young permanent teeth were evaluated by immunohistochemistry with a human anti-VEGFR-2 antibody. Stained tissue sections were analyzed qualitatively under light microscopy. Here we observed that endothelial cells of both primary and permanent teeth showed positive immunostaining for VEGFR-2. Notably, VEGFR-2-positive cells in the primary teeth tended to be found close to the subodontoblastic layer, whereas the spatial distribution of VEGFR-2 immunostaining in the permanent teeth was more uniform. In conclusion, VEGFR-2 was expressed in the microvascular endothelial cells of both primary and young permanent teeth, which suggests that these cells are capable of responding to the morphogenetic and survival signals mediated by VEGF.

  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 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.

  8. Root length and alveolar bone level of impacted canines and adjacent teeth after orthodontic traction: a long-term evaluation

    PubMed Central

    da SILVA, Aldir Cordeiro; CAPISTRANO, Anderson; de ALMEIDA-PEDRIN, Renata Rodrigues; CARDOSO, Maurício de Almeida; CONTI, Ana Cláudia de Castro Ferreira; CAPELOZZA, Leopoldino

    2017-01-01

    Abstract Objective The aim of this retrospective study was to evaluate the long-term effects of orthodontic traction on root length and alveolar bone level in impacted canines and adjacent teeth. Material and Methods Sample consisted of 16 patients (nine males and seven females), mean initial age 11 years and 8 months presenting with unilaterally maxillary impacted canines, palatally displaced, treated with the same surgical and orthodontic approach. Teeth from the impacted-canine side were assigned as Group I (GI), and contralateral teeth as control, Group II (GII). The mean age of patients at the end of orthodontic treatment was 14 years and 2 months and the mean post-treatment time was 5 years and 11 months. Both contralateral erupted maxillary canines and adjacent teeth served as control. Root length and alveolar bone level (buccal and palatal) were evaluated on cone-beam computed tomography (CBCT) images. The comparison of root length and alveolar bone level changes between groups were assessed by applying paired t-test, at a significance level of 5% (p<0.05). Results There were no statistically significant differences in root length and buccal and palatal bone levels of canines and adjacent teeth among groups. Conclusions Impacted canine treatment by closed-eruption technique associated with canine crown perforation, has a minimal effect on root length and buccal and palatal alveolar bone level in both canine and adjacent teeth, demonstrating that this treatment protocol has a good long-term prognosis. PMID:28198979

  9. 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.

  10. Treatments for intrusive luxation in permanent teeth: a systematic review and meta-analysis.

    PubMed

    Costa, L A; Ribeiro, C C C; Cantanhede, L M; Santiago Júnior, J F; de Mendonça, M R; Pereira, A L P

    2017-02-01

    Intrusive luxation is a severe form of dental trauma and there is no consensus regarding its management for permanent teeth. A systematic review and meta-analysis was performed to identify the appropriate treatment for teeth with intrusive luxation. The PubMed/MEDLINE, Embase, US Clinical Trials, and ISRCTN Registry electronic databases were used to search for articles in English and unpublished studies without a date limit. Eligible studies evaluated periodontal results (root resorption as the primary outcome; marginal bone defects and/or pulpal changes as secondary outcomes) after spontaneous re-eruption (SRE), orthodontic repositioning (ORP), or surgical repositioning (SRP) for patients with one or more traumatically intruded permanent teeth. Risk ratios with 95% confidence intervals were used to compare treatments. The meta-analysis revealed no significant difference (P>0.05) between SRP and SRE for root resorption. For secondary outcomes, SRE was significantly better than SRP and ORP (P<0.05). Subgroup analyses showed no significant differences among treatments in teeth with completely formed roots (P>0.05) and a better prognosis when SRE was performed in teeth with incompletely formed roots (P<0.05). The available evidence does not allow us to conclude on the best treatment for traumatically intruded teeth. More reliable evidence is needed.

  11. Root growth during molar eruption in extant great apes.

    PubMed

    Kelley, Jay; Dean, Christopher; Ross, Sasha

    2009-01-01

    While there is gradually accumulating knowledge about molar crown formation and the timing of molar eruption in extant great apes, very little is known about root formation during the eruption process. We measured mandibular first and second molar root lengths in extant great ape osteological specimens that died while either the first or second molars were in the process of erupting. For most specimens, teeth were removed so that root lengths could be measured directly. When this was not possible, roots were measured radiographically. We were particularly interested in the variation in the lengths of first molar roots near the point of gingival emergence, so specimens were divided into early, middle and late phases of eruption based on the number of cusps that showed protein staining, with one or two cusps stained equated with immediate post-gingival emergence. For first molars at this stage, Gorilla has the longest roots, followed by Pongo and Pan. Variation in first molar mesial root lengths at this stage in Gorilla and Pan, which comprise the largest samples, is relatively low and represents no more than a few months of growth in both taxa. Knowledge of root length at first molar emergence permits an assessment of the contribution of root growth toward differences between great apes and humans in the age at first molar emergence. Root growth makes up a greater percentage of the time between birth and first molar emergence in humans than it does in any of the great apes.

  12. The effect of temporary restorative materials on fracture resistance of endodontically treated teeth.

    PubMed

    Milani, Amin Salem; Froughreyhani, Mohammad; Mohammadi, Hosein; Tabegh, Fatemeh Ghasemi; Pournaghiazar, Fatemeh

    2016-01-01

    This study was designed to investigate the fracture strength of endodontically treated teeth temporarily restored with some commonly used interim materials. Of 90 extracted maxillary premolars used in this study, 15 were left intact as the positive control. Endodontic treatment was performed on the remaining 75 teeth. The endodontically treated teeth were then randomly assigned to 5 groups (n = 15). One group was not restored and served as the negative control. In the remaining 4 experimental groups, the teeth were restored with a temporary cement: Zonalin, IRM, Coltosol, or Fuji II LC resin-modified glass ionomer (RMGI). The fracture strengths of all teeth were measured with a universal testing machine. The fracture strength of teeth restored with RMGI was significantly greater than that of other groups (P < 0.001), including intact teeth (P = 0.025). The fracture strength of teeth restored with other temporary materials was significantly lower than that of intact teeth (P < 0.05) but not significantly different from that of the negative control. From a structural resistance standpoint, RMGI may be the best choice for short-term temporary restoration of endodontically treated teeth. Other types of temporary restorative material had no reinforcing effect on tooth structure.

  13. Characteristics of dental pulp in human upper first premolar teeth based on immunohistochemical and morphometric examinations.

    PubMed

    Tomaszewska, Joanna Maria; Miskowiak, Bogdan; Matthews-Brzozowska, Teresa; Wierzbicki, Piotr

    2013-01-01

    Teeth extracted for orthodontic reasons are commonly considered as healthy. Therefore, it is possible to examine structure of the dental pulp can be fully recognized and how it is affected by malocclusion. The aim of the study was to evaluate by immunohistochemistry (IHC) and morphometry dental pulp in human upper first premolar teeth extracted for orthodontic reasons. The material comprised 36 teeth of 20 patients in the age range 16-26 years. By the use of IHC markers the presence of immunocompetent cells (CD20, CD45RO, and CD68), blood vessels (CD31) and nerves (PGP9.5) were examined in the pulp. Inflammatory infiltrates and tissue atrophy were observed in 24 and 10 teeth, respectively. Strong positive correlation between the width of the odontoblastic layer, the number of rows of odontoblast nuclei and the increase of MVA (microvessel area) in the pulp of atrophic teeth was found. The cellular infiltrations found in H&E-stained sections were identified by IHC as memory T cells (CD45RO+) and B lymphocytes (CD20+) with macrophages (CD68+) present at the periphery. The CD20 antigen was intensively expressed in 13 teeth, CD45RO in 33 teeth, and CD68 in 20 teeth. Thus, despite the lack of any clinical signs of pulp disease many teeth extracted for orthodontic reasons show focal pulp inflammation and atrophy which probably results from the malocclusion stress accompanying teeth crowding.

  14. Preprosthetic movement of anterior teeth.

    PubMed

    Melsen, B

    1982-05-01

    Preprosthetic movement of anterior teeth is often performed on patients with missing anterior teeth, providing a better basis for subsequent bridgework. This can often be achieved by horizontal tooth movements of a tipping or translatory art whilst other patients present problems of a vertical nature with a deep overbite inconsistent with a healthy periodontal status. Intrusive tooth movements are needed as changes in facial height are not tolerated. The importance of understanding the biological basis for tooth movements in the planning of the biomechanics is stressed. Forces should be monitored according to the amount of general and local bone loss.

  15. Models of volcanic eruption hazards

    SciTech Connect

    Wohletz, K.H.

    1992-06-01

    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.

  16. 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.

  17. 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

  18. Correlation between three color coordinates of human teeth.

    PubMed

    Lee, Yong-Keun

    2014-11-01

    The objective was to determine whether there were significant correlations in the three color coordinates within each of two color coordinate systems, such as the Commission Internationale de l’Eclairage (CIE) L*a*b* system, and the lightness, chroma, and hue angle system, of human vital teeth. The color of six maxillary and six mandibular anterior teeth was measured by the Shade Vision System. Pearson correlations between each pair of the color coordinates were determined (α=0.01 ). The influence of two color coordinates on the other color coordinate was determined with a multiple regression analysis (α=0.01 ). Based on correlation analyses, all the color coordinate pairs showed significant correlations except for the chroma and hue angle pair. The CIE L* was negatively correlated with the CIE a*,b*, and chroma, but positively correlated with the hue angle. The CIE a* was positively correlated with the CIE b* and chroma. Tooth color coordinates were correlated each other. Lighter teeth were less chromatic both in the CIE a* and b* coordinates. Therefore, it was postulated that the three color coordinates of human teeth were harmonized within certain color attribute ranges, and a lack of correlations in these coordinates might indicate external/internal discolorations and/or anomalies of teeth.

  19. The development and replacement of teeth in viviparous caecilians.

    PubMed

    Wake, M H

    1976-01-01

    Tooth development and replacement in fetal and adult viviparous caecilians (Amphibia: Gymnophiona) are described and analyzed according to current theories of tooth succession. The fetal dentition differs from that of the adult in morphology, position, and function. Teeth are used by fetuses to scrape the oviducal epithelium, thus stimulating the secretion of a nutrient substance. Fetal dentitions vary in morphology and position in different species. The ontogeny of teeth of several species is described and the patterns of addition of loci and of replacement are analyzed. Loci are added both posteriorly along the jaw and between existing loci as the jaw grows prior to ossification; subsequently addition is restricted to the posterior part of the jaw. Tooth replacement is alternate. The several rows and patches of teeth are the result of retention of replacement series on the dentigerous elements. Tooth development and replacement in a series of juveniles and adults of different sizes in a single species are also considered. Post-fetal patterns of development and replacement are similar to those seen in larvae and adults of oviparous species. Variation in numbers of teeth and proportions of teeth at particular stages occurs ontogenetically and among individuals of the same size, though proportions occur in a similar pattern throughout the series. The general pattern of tooth replacement in fetuses and adults can be explained by either Edmund's Zahnreihen theory or by Osborn's Tooth Family theory, but replacement in fetal tooth patches and the fetal-adult dentitional transition are explained by neither.

  20. Evidence for different eruptive conditions for two simultaneous, late Miocene, rhyolitic phreatomagmatic eruptions: Jemez Mountains, New Mexico

    SciTech Connect

    Gay, K.R.; Smith, G.A. . Dept. of Earth and Planetary Sciences)

    1993-04-01

    The Peralta Tuff Member of the Bearhead Rhyolite records episodic, rhyolitic volcanism during the late Miocene. It is composed of primary and reworked pyroclastic-flow (PF), tephra-fall (TF), and pyroclastic-surge (PS) deposits intercalated with braided-stream deposits. Two eruptive units have been informally named the Tuffs of West Mesa (TWM) and the Tuffs of Lower Peralta Canyon (TLPC). The TWM consist of 20 m of PF and minor PS deposits erupted from a vent in the Bearhead Park dome complex. In most places the TLPC consist of 50 m of PF, PS, and TF and were erupted from a vent located 7 km SE of Bearhead Peak. The absence of inter-eruptive sediments, erosional surfaces, or paleosols, along with the intercalated nature of the two units, indicates that the two eruptions were simultaneous. Granulometric, vesiculation, petrographic, and stratigraphic data indicate that the TWM eruption began with a phreatomagmatic (PM) component, resulting in the formation of a tuff ring at least 70 m thick, and ended with [ge]20 m of drier PF that traveled at least 6 km from the vent. The TLPC eruption began with several PM eruptive cycles of wet, ash-rich, low-angle x-bedded PS to drier, pumiceous, lapilli-rich PS. Abundant fragments of underlying rift-fill sediments decrease upward in the cycles. The cyclic deposits were followed by 20 m of pumice-rich, x-bedded PS, containing only rare sedimentary fragments. The TLPC eruption concluded with a 2 m TF. The greater phreatomagmatic component to the TLPC eruption, despite its proximity to the simultaneously active TWM vent, is apparently related to the mixing of magma with basin-fill sediments at a topographically lower ([ge]300 m) position and at a site that probably has less subjacent, relatively dry, older volcanic rocks.

  1. 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)

  2. Clinical survey of fractured teeth.

    PubMed

    Gher, M E; Dunlap, R M; Anderson, M H; Kuhl, L V

    1987-02-01

    Through a standardized procedure using clinical examination, interviews, and dental history, this 2-year study documents 100 cases of tooth fracture in 98 patients. For comparison, pertinent information was also recorded for more than 2,000 teeth in a randomly selected sample population. Two chief types of fracture were found: incomplete crown-root fractures and root fractures associated with earlier endodontic therapy.

  3. The effects of colony-stimulating factor-1 on tooth eruption in the toothless (osteopetrotic) rat in relation to the critical periods for bone resorption during tooth eruption.

    PubMed

    Iizuka, T; Cielinski, M; Aukerman, S L; Marks, S C

    1992-08-01

    The toothless (tl) rat is an osteopetrotic mutation characterized by a generalized skeletal sclerosis, reduced bone resorption, few osteoclasts and a total absence of erupted teeth. This mutation is not cured by bone marrow transplants from normal littermates. It is known that the skeletal defects in tl rats are greatly improved after treatment with colony-stimulating factor-1 (CSF-1). This investigation concerns the effects of CSF-1 on the development and eruption of the dentition of tl rats. Untreated tl rats had no erupted teeth by 56 days after birth, and the roots of incisors and molars were severely distorted by compression against bone. The apex of the mandibular incisor did not extend past the first molar and continued growth of its apical end produced odontoma-like masses consisting of distorted dentine and enamel matrices. In addition, few osteoclasts were seen on alveolar bone surfaces surrounding the developing teeth. Mutants given CSF-1 were characterized by delayed eruption of all molars and sometimes incisors. The incidence of incisor eruption was related inversely to the age at which CSF-1 treatment began. Molars of treated tl rats had well-developed roots similar to those in normal rats. Treated mutants had numerous osteoclasts in alveolar bone and well-developed haemopoietic marrow spaces in the mandible. Histochemical staining for both tartrate-resistant acid phosphatase and tartrate-resistant acid ATPase was reduced or negligible in osteoclasts of untreated tl rats, heavy in normal osteoclasts and of intermediate intensity in CSF-1-treated mutants.(ABSTRACT TRUNCATED AT 250 WORDS)

  4. 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

  5. Take Care of Your Child's Teeth

    MedlinePlus

    ... This Topic En español Take Care of Your Child’s Teeth Browse Sections The Basics Overview Tooth Decay ... can cause cavities (holes) in teeth. Is my child at risk for tooth decay? Tooth decay is ...

  6. 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.

  7. Supragingival Microbial Profiles of Permanent and Deciduous Teeth in Children with Mixed Dentition

    PubMed Central

    Shi, Weihua; Qin, Man; Chen, Feng; Xia, Bin

    2016-01-01

    Objectives The present study was designed to investigate the microbial profiles of teeth in different locations in mixed-dentition-stage children, and to compare the microbiomes of permanent and deciduous teeth in the same healthy oral cavity. Methods Supragingival plaque samples of teeth in various locations—the first permanent molars, deciduous molars, deciduous canines and incisors and permanent incisors—were collected from 20 healthy mixed-dentition-stage children with 10–12 permanent teeth erupted. Plaque DNA was extracted, and the V3–V4 hypervariable region of the bacterial 16S rRNA gene was amplified and subjected to sequencing. Results On average, 18,051 high-quality sequences per sample were generated. Permanent tooth sites tended to host more diverse bacterial communities than those of deciduous tooth sites. A total of 12 phyla, 21 classes, 38 orders, 66 families, 74 genera were detected ultimately. Five predominant phyla (Proteobacteria, Firmicutes, Bacteroidetes, Fusobacteria and Actinobacteria) were highly variable among sites. Of 26 genera with a mean relative abundance of >0.1%, 16 showed significant differences in relative abundance among the groups. More than 20% of the total operational taxonomical units were detected only in permanent or deciduous teeth. The variation in the microbial community composition was due mainly to permanent teeth being enriched in Actinomyces and deciduous teeth in Treponema. The core microbiome of supragingival plaque in mixed dentition comprised 19 genera with complex correlationships. Conclusion Our results suggest differences in microbial diversity and composition between permanent and deciduous teeth sites in mixed dentition. Moreover, the core microbiome of these sites was determined. These findings enhance our understanding of the development of the native oral microbiota with age. PMID:26752284

  8. Agenesis of Multiple Primary and Permanent Teeth Unilaterally and its Possible Management

    PubMed Central

    Ephraim, Rena; Rajamani, T; Feroz, TP Mohammed; Abraham, Sajith

    2015-01-01

    uprighting and protecting maxillary right posteriors to accommodate the tongue and rectify speech. Restorative procedures involved fabrication of a removable partial denture as a temporary measure to restore missing teeth, improve esthetics, give lingual support to the lower lip, prevent further downward growth of the right maxillary ridge and to prevent supra eruption of these teeth. PMID:26028909

  9. Agenesis of multiple primary and permanent teeth unilaterally and its possible management.

    PubMed

    Ephraim, Rena; Rajamani, T; Feroz, Tp Mohammed; Abraham, Sajith

    2015-05-01

    uprighting and protecting maxillary right posteriors to accommodate the tongue and rectify speech. Restorative procedures involved fabrication of a removable partial denture as a temporary measure to restore missing teeth, improve esthetics, give lingual support to the lower lip, prevent further downward growth of the right maxillary ridge and to prevent supra eruption of these teeth.

  10. A complex odontoma of the anterior maxilla associated with an erupting canine.

    PubMed

    Pillai, Ajay; Moghe, Swapnil; Gupta, Mithilesh K; Pathak, Abhishek

    2013-11-12

    Many developmental anomalies of the jaw are accidentally diagnosed during radiographic investigations for other symptoms. Complex odontomas are odontogenic tumours, relatively rare in the anterior maxilla and generally asymptomatic. Frequently the odontoma may interfere with the eruption of teeth. This paper describes a case of complex odontoma in an 8-year-old girl, which resulted in the palatal displacement of the lateral incisor and an erupting permanent canine. A calcified mass was seen on the radiograph and was provisionally diagnosed as an odontoma which was surgically enucleated. Routine follow-up was carried out for more than 1 year and no recurrence was seen.

  11. 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

  12. 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

  13. 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

  14. 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

  15. 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.

  16. A FILAMENT ERUPTION ON 2010 OCTOBER 21 FROM THREE VIEWPOINTS

    SciTech Connect

    Filippov, Boris

    2013-08-10

    A filament eruption on 2010 October 21 observed from three different viewpoints by the Solar Terrestrial Relations Observatory and the Solar Dynamic Observatory is analyzed by also invoking data from the Solar and Heliospheric Observatory and the Kanzelhoehe Solar Observatory. The position of the filament just before the eruption at the central meridian not far from the center of the solar disk was favorable for photospheric magnetic field measurements in the area below the filament. Because of this, we were able to calculate with high precision the distribution of the coronal potential magnetic field near the filament. We found that the filament began to erupt when it approached the height in the corona where the magnetic field decay index was greater than 1. We also determined that during the initial stage of the eruption the filament moved along the magnetic neutral surface.

  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. Genetic background of supernumerary teeth

    PubMed Central

    Subasioglu, Asli; Savas, Selcuk; Kucukyilmaz, Ebru; Kesim, Servet; Yagci, Ahmet; Dundar, Munis

    2015-01-01

    Supernumerary teeth (ST) are odontostomatologic anomaly characterized by as the existence excessive number of teeth in relation to the normal dental formula. This condition is commonly seen with several congenital genetic disorders such as Gardner's syndrome, cleidocranial dysostosis and cleft lip and palate. Less common syndromes that are associated with ST are; Fabry Disease, Ellis-van Creveld syndrome, Nance-Horan syndrome, Rubinstein-Taybi Syndrome and Trico–Rhino–Phalangeal syndrome. ST can be an important component of a distinctive disorder and an important clue for early diagnosis. Certainly early detecting the abnormalities gives us to make correct management of the patient and also it is important for making well-informed decisions about long-term medical care and treatment. In this review, the genetic syndromes that are related with ST were discussed. PMID:25713500

  19. 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

  20. Earthquake-induced static stress change in promoting volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Bonali, Fabio Luca; Tibaldi, Alessandro; Corazzato, Claudia

    2014-05-01

    The aim of this work is to study how earthquakes could favour new eruptions, focusing the attention on earthquake-induced static effects in two different case sites, where 9 seismic events with Mw ≥ 8 occurred in the last century: the Alaska-Aleutian and Chilean volcanic arcs. We followed a novel approach that resolves the earthquake-induced static stress change normal to the magma pathway of each volcano instead of considering the general crustal volume. We also considered other parameters that may contribute to control eruptions, such as magma composition and viscosity, magma chamber depth and local tectonic settings. The dataset includes a total of 51 eruptions following the earthquakes; 33 represent first new eruptions occurred at each single volcano. Comparison of the eruption rate before and after each earthquake suggests that 26 out of the 33 first new eruptions have a positive relation with the studied earthquakes; 13 out of 26 represent awakening events, which are first new eruptions occurred at volcanoes with non-continuous eruptive activity that had no eruptions in the five years before the earthquake. The sensitivity analysis performed for the 2010 Chile earthquake shows that the N-S- and NE-SW-striking magma pathways suffered a larger unclamping in comparison with those striking NW-SE and E-W. Magma pathway geometry contributes to control the magnitude of the static stress change induced by large earthquakes, with differences of up to 8 times among magma-feeding planes of different orientation at the same volcano. This range of diverse values is larger for the volcanoes closer to the epicentre. The possible error in the estimate of magma chamber depth has a minimum effect on the results since the sensitivity analysis shows that the range of stress changes with depth is about 1.5 orders of magnitude smaller than the range linked to variations in the magma pathway strike. Results suggest that unclamping effect promoted eruptions that occurred at non

  1. Iron deposition in modern and archaeological teeth

    NASA Astrophysics Data System (ADS)

    Williams, A.-M. M.; Siegele, R.

    2014-09-01

    Iron surface concentrations and profile maps were measured on the enamel of archaeological and modern teeth to determine how iron is deposited in tooth enamel and if it was affected by the post-mortem environment. Teeth from Australian children who died in the second half of the 19th century were compared with contemporary teeth extracted for orthodontic purposes. Surface analysis of the teeth was performed using the 3 MV Van Der Graff Accelerator at The Australian Nuclear Science and Technology Organisation (ANSTO), Sydney, Australia. A small sample of teeth were then cut in the mid sagittal plane and analysed using ANSTO High Energy Heavy Ion Microprobe. Maps and linear profiles were produced showing the distribution of iron across the enamel. Results show that both the levels and distribution of iron in archaeological teeth is quite different to contemporary teeth, raising the suggestion that iron has been significantly altered by the post-mortem environment.

  2. 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.

  3. Large and small volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Gudmundsson, Agust; Mohajeri, Nahid

    2013-04-01

    Despite great progress in volcanology in the past decades, we still cannot make reliable forecasts as to the likely size (volume, mass) of an eruption once it has started. Empirical data collected from volcanoes worldwide indicates that the volumes (or masses) of eruptive materials in volcanic eruptions are heavy-tailed. This means that most of the volumes erupted from a given magma chamber are comparatively small. Yet, the same magma chamber can, under certain conditions, squeeze out large volumes of magma. To know these conditions is of fundamental importance for forecasting the likely size of an eruption. Thermodynamics provides the basis for understanding the elastic energy available to (i) propagate an injected dyke from the chamber and to the surface to feed an eruption, and (ii) squeeze magma out of the chamber during the eruption. The elastic energy consists of two main parts: first, the strain energy stored in the volcano before magma-chamber rupture and dyke injection, and, second, the work done through displacement of the flanks of the volcano (or the margins of a rift zone) and the expansion and shrinkage of the magma chamber itself. Other forms of energy in volcanoes - thermal, seismic, kinetic - are generally important but less so for squeezing magma out of a chamber during an eruption. Here we suggest that for (basaltic) eruptions in rift zones the strain energy is partly related to minor doming above the reservoir, and partly to stretching of the rift zone before rupture. The larger the reservoir, the larger is the stored strain energy before eruption. However, for the eruption to be really large, the strain energy has to accumulate in the entire crustal segment above the reservoir and there will be additional energy input into the system during the eruption which relates to the displacements of the boundary of the rift-zone segment. This is presumably why feeder dykes commonly propagate laterally at the surface following the initial fissure

  4. Variation in elemental composition of human teeth and its application for feasible species identification.

    PubMed

    Nganvongpanit, Korakot; Buddhachat, Kittisak; Piboon, Promporn; Euppayo, Thippaporn; Mahakkanukrauh, Pasuk

    2017-02-01

    Identifying human remains is a primary task in forensic science. In this study, we propose a possible new technique, handheld X-ray fluorescence (HHXRF), for determining whether a suspected tooth is an authentic human tooth. A total of 444 teeth obtained from 111 human skulls (male=62, female=49) aged between 30-67 years (51.81±8.37 years) were used as subjects. The teeth were scanned by HHXRF to acquire their elemental profile. Differences in elemental composition were analyzed for different tooth positions (numbers 1-32), between crown and root, and between sexes (male and female); also, the proportion of elements in relation to different human ages was examined. Teeth from 20 different animal species, serving as non-human teeth samples, were used to distinguish between human and non-human teeth through a stepwise discriminant analysis. Our results revealed that different tooth positions, different regions (crown and root) of a tooth, and different sexes demonstrated disparities in the proportion of several elements. The accuracy rate of predicting sex based on the elemental profile of human teeth was 65.5%. Likewise, a dissimilar distribution of elements between human and non-human teeth was observed, leading to a high degree of correctness of 83.2% for distinguishing them. In conclusion, elemental analysis by HHXRF could serve as a promising candidate tool for identifying human teeth in forensic science, but is ineffective for sex determination.

  5. Pre-Eruptive Intracoronal Resorption (PEIR): Literature Review and Case Report.

    PubMed

    Omar, Samah; Choi, Jessica; Nelson, Bonnie; Shin, Michelle; Chen, Jung-Wei

    2015-05-01

    Pre-eruptive intracoronal resorption (PEIR) are lesions that are often located in the occlusal portion of the crown in unerupted teeth. The etiology and pathology of these lesions remain unclear and most go undetected until later stages of development. Prognosis is dependent on early detection, and conservative treatment is recommended. This report reviews the etiology, prevalence, diagnosis and treatment of PEIR and describes a case of a permanent second molar with PEIR diagnosed in an 11-year-old patient.

  6. 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

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

    PubMed

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

    2015-12-01

    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.

  8. Characterization of Solar Eruptions reported by EruptionPatrol

    NASA Astrophysics Data System (ADS)

    Hurlburt, Neal

    2015-04-01

    Observation of the solar atmosphere reveals a wide range of real and apparent motions, from small scale jets and spicules to global-scale coronal mass ejections. Identifying and characterizing these motions are essential to advance our understanding the drivers of space weather. A method for automatically identifying eruptions near the solar surface (either from filaments or otherwise) has recently been developed and integrated into the Heliophysics Events Knowledgebase. Here we report on the EruptionPatrol module for identifying eruptions in data collected by the SDO/AIA instrument and on the characterization and analysis of its output. A cluster analysis on the time periods reported by EruptionPatrol demarcates several large-scale events spanning significant portions of the solar disk with lifetimes of up to six hours.

  9. An Analysis of Eruptions Detected by the LMSAL Eruption Patrol

    NASA Astrophysics Data System (ADS)

    Hurlburt, N. E.; Higgins, P. A.; Jaffey, S.

    2014-12-01

    Observations of the solar atmosphere reveals a wide range of real and apparent motions, from small scale jets and spicules to global-scale coronal mass ejections. Identifying and characterizing these motions are essential to advance our understanding the drivers of space weather. Automated and visual identifications are used in identifying CMEs. To date, the precursors to these — eruptions near the solar surface — have been identified primarily by visual inspection. Here we report on an analysis of the eruptions detected by the Eruption Patrol, a data mining module designed to automatically identify eruptions from data collected by Solar Dynamics Observatory's Atmospheric Imaging Assembly (SDO/AIA). We describe the module and use it both to explore relations with other solar events recorded in the Heliophysics Event Knowledgebase and to identify and access data collected by the Interface Region Imaging Spectrograph (IRIS) and Solar Optical Telescope (SOT) on Hinode for further analysis.

  10. 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

  11. Fixed drug eruption to sitagliptin.

    PubMed

    Gupta, Mrinal; Gupta, Anish

    2015-01-01

    Fixed drug eruption is a common adverse effect seen with various drugs notably antibiotics, antiepileptics and non-steroidal anti-inflammatory drugs. Herein we report a case of Sitagliptin induced fixed drug eruption in a 46 year old female who developed circumscribed, erythematous macules all over the body within one week of initiation of Sitagliptin. The lesions resolved with residual hyperpigmentation on cessation of the drug. The diagnosis was confirmed by an oral provocation test which led to a reactivation of the lesions. To the best of our knowledge, this is the first case of fixed drug eruption to Sitagliptin reported in the literature.

  12. Fixed drug eruption to propofol.

    PubMed

    Allchurch, L G V; Crilly, H

    2014-11-01

    We present a case of fixed drug eruption to propofol following a series of sedations of a patient for a number of day case procedures. The patient experienced oedema and blistering of his penis, increasing in severity and duration following each subsequent exposure. The diagnosis was confirmed by punch biopsy following an intravenous challenge test with propofol. Whilst reports of fixed drug eruptions to anaesthetic induction agents are uncommon, a number of drugs used commonly by anaesthetists are known triggers. We discuss fixed drug eruptions in relation to anaesthetic practice, aiming to raise awareness of this adverse drug reaction.

  13. 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.

  14. 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.

  15. Tricho-dento-osseous syndrome and precocious eruption

    PubMed Central

    Kaul, Rahul; Saha, Subrata; Sarkar, Subir

    2017-01-01

    Tricho-dento-osseous syndrome (TDO), an uncommon form of ectodermal dysplasia is an autosomal dominant genetic disorder which is characterized by inherited defects in tissues arising from epithelial-mesenchymal interaction. Genetic studies have revealed that it is caused by mutation in the DLX3 gene. TDO presents with a great phenotypic heterogeneity and studies have suggested that this heterogeneity is the result of environmental factors or other genetic modifiers. In this article, we report a case of TDO in which the child had typical clinical features of hair, teeth and bone defects, as seen in TDO. Parents of the child were unaffected. Genetic analysis of the child revealed mutation in DLX3 gene. The child also showed precocious eruption of the permanent molars, a clinical feature which has been rarely reported. We suggest that the precocious eruption seen in TDO is probably due to a markedly increased osteoblastic activity. Key words:Tricho-dento-osseous syndrome, DLX3 gene, precocious eruption. PMID:28298997

  16. Ritodrine-induced pustular eruptions distinctly resembling impetigo herpetiformis.

    PubMed

    Kuwabara, Yoshimitsu; Sato, Atsuki; Abe, Hiroko; Abe, Sumino; Kawai, Naoki; Takeshita, Toshiyuki

    2011-01-01

    A 27-year-old nulligravida woman without a history of dermatosis was hospitalized for threatened preterm labor at 29 weeks' gestation; therefore, continuous infusion of ritodrine hydrochloride was started. At 31 weeks' gestation, erythematous plaques appeared and spread over the body surface; therefore, a topical steroid preparation was applied. At 32 weeks' gestation, the eruptions developed into irregular annular areas of erythema with multiple pustules accompanied by severe itching, and oral prednisolone treatment was started. Bacterial cultures of the pustules were negative, and a crural cutaneous biopsy revealed Kogoj's spongiform pustules. Based on the clinicopathological findings, the most likely diagnosis was impetigo herpetiformis, which causes cutaneous symptoms closely resembling pustular psoriasis in pregnant females without a history of psoriasis. To rule out ritodrine-induced pustular eruptions, the ritodrine infusion was stopped and treatment with an MgSO(4) preparation was started at 33 weeks' 3 days' gestation; however, the uterine contractions could not be suppressed. Because of the patient's highly edematous, severely painful feet, a cesarean section was performed the same day. Within several days of delivery, the eruptions began to resolve, and no recurrence was observed after treatment with oral prednisolone was stopped 31 days after delivery. On the basis of a positive patch test for ritodrine, we diagnosed pustular drug eruptions caused by ritodrine hydrochloride. Although ritodrine-induced pathognomonic cutaneous eruptions are rare, we would like to emphasize that ritodrine can cause drug-induced pustular eruptions distinctly resembling life-threatening impetigo herpetiformis.

  17. The cytology of the dental follicle and adjacent alveolar bone during tooth eruption in the dog.

    PubMed

    Marks, S C; Cahill, D R; Wise, G E

    1983-11-01

    Previous studies from our laboratories have shown that premolar eruption in dogs depends upon the presence of the dental follicle and is independent of root or crown growth or attachment to the oral epithelium. The present study is an analysis of the cellular composition of the dental follicle and the cellular investment of the adjacent walls of the bony crypt before and during eruption of the third and fourth mandibular permanent premolars in young beagle dogs. Four premolar follicles and their adjacent bony crypts were examined at 2-week intervals over 12 weeks before and during eruption of these teeth. Tissues were removed, fixed, processed, and oriented so that each follicle and the adjacent crypt wall could be reproducibly examined in vertical and horizontal planes. Mononuclear cells with abundant cytoplasm, euchromatic nuclei, and prominent nucleoli were present in juxtavascular location in the coronal part of the dental follicle; and these cells increased in number immediately preceding and during tooth eruption in parallel with an increase in osteoclasts on the adjacent crypt wall. These data are interpreted to mean that the coronal part of the dental follicle may coordinate the alveolar bone resorption required for tooth eruption by attracting and directing to the crypt wall a population of mononuclear cells, which either become osteoclasts and/or direct osteoclastic activity during tooth eruption.

  18. A Statistical Study of Solar Filament Eruptions

    NASA Astrophysics Data System (ADS)

    Schanche, Nicole; Aggarwal, Ashna; Reeves, Kathy; Kempton, Dustin James; Angryk, Rafal

    2016-05-01

    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, McCauley et al. 2015) has shown a positive correlation (70-80%) between the occurrence of filament eruptions and coronal mass ejections (CME’s). In this study, we attempt to use properties of the filament in order to predict whether or not a given filament will erupt. This prediction would help to better predict the occurrence of an oncoming CME. To track the evolution of a filament over time, a spatio-temporal algorithm that groups separate filament instances from the Heliophysics Event Knowledgebase (HEK) into filament tracks was developed. Filament features from the HEK metadata, such as length, chirality, and tilt are then combined with other physical features, such as the overlying decay index for two sets of filaments tracks - those that erupt and those that remain bound. Using statistical methods such as the Kolmogrov-Smirnov test and a Random Forest Classifier, we determine the effectiveness of the combined features in prediction. We conclude that there is significant overlap between the properties of filaments that erupt and those that do not, leading to predictions only ~5-10% above chance. However, the changes in features, such as a change in the filament's length over time, were determined to have the highest predictive power. We discuss the possible physical connections with the change in these features."This project has been supported by funding from the Division of Advanced Cyberinfrastructure within the Directorate for Computer and Information Science and Engineering, the Division of Astronomical Sciences within the Directorate for Mathematical and Physical Sciences, and the Division of Atmospheric and Geospace Sciences within the Directorate for Geosciences, under NSF award #1443061.”

  19. Magma flow, eruption column and magma pressure change during 2010 Eyjafjallajökull and 2011 Grímsvötn eruptions, Iceland: Constraints from volcano geodesy on physical models of eruptive processes

    NASA Astrophysics Data System (ADS)

    Sigmundsson, F.; Hreinsdottir, S.; Hooper, A. J.; Grapenthin, R.; Heimisson, E. R.; Ofeigsson, B.; Sturkell, E. C.; Roberts, M. J.; Gudmundsson, M. T.; Hoskuldsson, A.; Bjornsson, H.; Arason, P.; Parks, M.; Dumont, S.; Drouin, V.

    2014-12-01

    Ground deformation in relation to 2010 Eyjafjallajökull and 1998, 2004 and 2011 Grímsvötn eruptions in Iceland provide constraints on subsurface magma flow and pressure change. When compared with eruptive activity, eruption column and estimates of mass flow rate they can be used to constrain physical models of eruptive processes. The 1998 and 2004 Grímsvötn eruptions were captured by intermittent GPS observations but in 2011 the detailed temporal evolution of co-eruptive deformation was revealed by a kinematic 1 Hz solutions for the position of a single continuous GPS site on the volcano, supplemented with ground tilt observations. The observations can be explained by inflow of magma and pressure buildup between eruptions in a shallow chamber at about 1.7 km depth beneath the center of the Grímsvötn caldera complex, and pressure drop and magma outflow during eruptions. The rate of pressure change in the magma chamber correlates with the height of the volcanic plume over the course of the 2011 eruption. Peaks in activity relate to periods of rapid pressure drop in the chamber. GPS observations and interferometric analysis of satellite radar images from the TerraSAR-X satellite show that the explosive 2010 eruption at Eyjafjallajökull was on the other hand associated with gradual contraction of a source, distinct from pre-eruptive inflation sources at the volcano. For the initial 10-days of the summit eruption, a deflating sill source under the summit at about 5 km depth can explain the observed deformation, but then the source geometry appears to evolve. The rate of deflation was interrupted by inflow of new magma into the deflating source during the eruption in relation to peaks in explosive activity. The contrasting behavior of the two volcanoes is interpreted in terms of different magma plumbing systems of the volcanoes. In both cases, the erupted volume of magma is much larger than the inferred co-eruptive volume change, attributed to compressibility of

  20. 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

  1. CONTRACTING AND ERUPTING COMPONENTS OF SIGMOIDAL ACTIVE REGIONS

    SciTech Connect

    Liu Rui; Wang Yuming; Liu Chang; Wang Haimin; Toeroek, Tibor

    2012-10-01

    It has recently been noted that solar eruptions can be associated with the contraction of coronal loops that are not involved in magnetic reconnection processes. In this paper, we investigate five coronal eruptions originating from four sigmoidal active regions, using high-cadence, high-resolution narrowband EUV images obtained by the Solar Dynamic Observatory (SDO). The magnitudes of the flares associated with the eruptions range from GOES class B to class X. Owing to the high-sensitivity and broad temperature coverage of the Atmospheric Imaging Assembly (AIA) on board SDO, we are able to identify both the contracting and erupting components of the eruptions: the former is observed in cold AIA channels as the contracting coronal loops overlying the elbows of the sigmoid, and the latter is preferentially observed in warm/hot AIA channels as an expanding bubble originating from the center of the sigmoid. The initiation of eruption always precedes the contraction, and in the energetically mild events (B- and C-flares), it also precedes the increase in GOES soft X-ray fluxes. In the more energetic events, the eruption is simultaneous with the impulsive phase of the nonthermal hard X-ray emission. These observations confirm that loop contraction is an integrated process in eruptions with partially opened arcades. The consequence of contraction is a new equilibrium with reduced magnetic energy, as the contracting loops never regain their original positions. The contracting process is a direct consequence of flare energy release, as evidenced by the strong correlation of the maximal contracting speed, and strong anti-correlation of the time delay of contraction relative to expansion, with the peak soft X-ray flux. This is also implied by the relationship between contraction and expansion, i.e., their timing and speed.

  2. Eruptive history and magmatic stability of Erebus volcano, Antarctica: Insights from englacial tephra

    NASA Astrophysics Data System (ADS)

    Iverson, Nels A.; Kyle, Philip R.; Dunbar, Nelia W.; McIntosh, William C.; Pearce, Nicholas J. G.

    2014-11-01

    tephrostratigraphy of the active Antarctic Erebus volcano was determined from englacial tephra on the ice-covered flanks of Erebus and an adjacent volcano. The tephra are used to reconstruct the eruptive history and magmatic evolution of Erebus. More fine-grained and blocky particles define tephra formed in phreatomagmatic eruptions and larger fluidal shards are characteristic of magmatic eruptions and in some cases both eruptive types are identified in a single mixed tephra. The eruptions forming the mixed tephra likely started as phreatomagmatic eruptions which transitioned into Strombolian eruptions as the nonmagmatic water source was exhausted. We reconstructed the eruptive history of Erebus using the tephra layers stratigraphic position, 40Ar/39Ar ages, shard morphology, and grain size. Major and trace element analyses of individual glass shards were measured by electron probe microanalysis and LA-ICP-MS. Trachybasalt, trachyte, and phonolite tephra were identified. All phonolitic tephra are Erebus-derived with compositions similar to volcanic bombs erupted from Erebus over the past 40 years. The tephra show that Erebus magma has not significantly changed for 40 ka. The uniformity of the glass chemical composition implies that the phonolite magma has crystallized in the same manner without change throughout the late Quaternary, suggesting long-term stability of the Erebus magmatic system. Trachyte and trachybasalt tephra were likely erupted from Marie Byrd Land and the McMurdo Sound area, respectively. The trachytic tephra can be regionally correlated and could provide an important time-stratigraphic marker in Antarctic ice cores.

  3. Tenofovir induced lichenoid drug eruption.

    PubMed

    Gupta, Mrinal; Gupta, Heena; Gupta, Anish

    2015-01-01

    Cutaneous adverse reactions are a common complication of anti-retroviral therapy. Tenofovir is a newer anti-retroviral drug belonging to the nucleotide reverse transcriptase inhibitor group. Systemic adverse effects like nausea, vomiting, diarrhea, hepatotoxicity and renal toxicity are common with tenofovir but cutaneous adverse effects are rare. Lichenoid drug eruptions are a common adverse effect seen with a large variety of drugs including antimalarials, antihypertensives, nonsteroidal anti-inflammatory drugs and diuretics. Lichenoid drug eruption is a rare cutaneous adverse effect of tenofovir with only a single case reported till date. Here, we report a case of tenofovir induced lichenoid drug eruption in a 54-year-old human immunodeficiency virus affected male who presented with generalized lichenoid eruption after 6 weeks of initiation of tenofovir and complete clearance on cessation of the drug.

  4. 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.

  5. Volcanology: Chronicling a medieval eruption

    NASA Astrophysics Data System (ADS)

    Ludlow, Francis

    2017-01-01

    The climatic response to the eruption of the Samalas Volcano in 1257 has been elusive. Medieval archives tell of a spatially variable reaction, with Europe and Japan experiencing severe cold compared to relative warmth in North America.

  6. 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

  7. 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

  8. Can tides influence volcanic eruptions?

    NASA Astrophysics Data System (ADS)

    Girona, T.; Huber, C.

    2015-12-01

    The possibility that the Moon-Sun gravitational force can affect terrestrial volcanoes and trigger eruptions is a controversial issue that has been proposed since ancient times, and that has been widely debated during the last century. The controversy arises mainly from two reasons. First, the days of initiation of eruptions are not well known for many volcanoes, and thus a robust statistical comparison with tidal cycles cannot be performed for many of them. Second, the stress changes induced by tides in the upper crust are very small (10-3 MPa) compared to the tensile strength of rocks (~ 10-1-10 MPa), and hence the mechanism by which tidal stresses might trigger eruptions is unclear. In this study, we address these issues for persistently degassing volcanoes, as they erupt frequently and thus the initiation time of a significant number of eruptions (>30) is well known in several cases (9). In particular, we find that the occurrence of eruptions within ±2 days from neap tides (first and third quarter moon) is lower than 34% (e.g., 29% for Etna, Italy; 28% for Merapi, Indonesia), which is the value expected if eruptions occur randomly with no external influence. To understand this preference for erupting far away from neap tides, we have developed a new lumped-parameter model that accounts for the deformation of magma reservoirs, a partially open conduit, and a gas layer where bubbles accumulate beneath volcanic craters before being released. We demonstrate that this system reservoir-conduit-gas layer acts as an amplifier of the tidal stresses, such that, when a volcano approaches to a critical state, the gas overpressure beneath the crater can reach up to several MPa more during a spring tide (full and new moon) than during a neap tide. This amplification mechanism can explain why active volcanoes are sensitive to the moon cycles.

  9. Altered Passive Eruption Complicating Optimal Orthodontic Bracket Placement: A Case Report and Review of Literature

    PubMed Central

    Chitra, Prasad

    2015-01-01

    An unusual case of altered passive eruption with gingival hyperpigmentation and a Class I malocclusion in a 12-year-old girl having no previous history of medication is presented. The patient reported with spacing in the upper arch, moderate crowding in the lower arch, anterior crossbite and excessive gingival tissue on the labial surfaces of teeth in both the arches. The inadequate crown lengths made placement of the orthodontic brackets difficult. Preadjusted orthodontic brackets have a very precise placement protocol which can affect tooth movement in all 3 planes of space if violated. The periodontal condition was diagnosed as altered passive eruption Type IA. Interdisciplinary treatment protocols including periodontal surgical and orthodontic procedures were used. The periodontal surgical procedures were carried out prior to orthodontic therapy and the results obtained were satisfactory. It is suggested that orthodontists should be aware of conditions like altered passive eruption and modalities of management. In most instances, orthodontic therapy is not hindered. PMID:26672498

  10. Polymorphous light eruption.

    PubMed

    Hölzle, E; Plewig, G; von Kries, R; Lehmann, P

    1987-03-01

    Polymorphous light eruption (PLE) is a common photodermatosis of unknown etiology. It afflicts mainly fair-skinned patients, with a preponderance of young females. There is, however, no absolute restriction as to age, sex, or race. Clinical variants include the papular, vesiculo-bullous, and hemorrhagic variety, as well as plaque, erythema multiforme-like, and insect bite (strophulus)-like types. Skin lesions appear only in certain exposed areas hours or a few days after intense sunshine, and are nearly always monomorphous in the same patient. The rash subsides spontaneously within several days without leaving scars. The histopathologic picture is characteristic and shows a perivascular lymphocytic infiltrate in the upper and middle corium with subepidermal edema, vacuolization of basal cells, and spongiosis in the lower epidermis. The most important differential diagnoses are solar urticaria, photosensitive erythema multiforme, and lupus erythematosus. The action spectrum of PLE is under debate. Reproduction of skin lesions has been reported with UVB, UVA, and, rarely, visible light, with UVA probably being the most effective part of the spectrum. More important than treatment of PLE is prophylaxis. UVA- and UVB-effective sunscreens are of some help. Phototherapy and especially photochemotherapy (psoralen + UVA; PUVA) offer effective ways to decrease light sensitivity. Systemic treatment with chloroquine or beta-carotene has been disappointing.

  11. Infrasound research of volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Marchetti, Emanuele; Ripepe, Maurizio

    2016-04-01

    Volcanic eruptions are efficient sources of infrasound produced by the rapid perturbation of the atmosphere by the explosive source. Being able to propagate up to large distances from the source, infrasonic waves from major (VEI 4 or larger) volcanic eruptions have been recorded for many decades with analogue micro-barometers at large regional distances. In late 1980s, near-field observations became progressively more common and started to have direct impact on the understanding and modeling of explosive source dynamics, to eventually play a primary role in volcano research. Nowadays, infrasound observation from a large variety of volcanic eruptions, spanning from VEI 0 to VEI 5 events, has shown a dramatic variability in terms of signature, excess pressure and frequency content of radiated infrasound and has been used to infer complex eruptive source mechanisms for the different kinds of events. Improved processing capability and sensors has allowed unprecedented precise locations of the explosive source and is progressively increasing the possibility to monitor volcanoes from distant records. Very broadband infrasound observations is also showing the relation between volcanic eruptions and the atmosphere, with the eruptive mass injection in the atmosphere triggering acoustic-gravity waves which eventually might control the ash dispersal and fallout.

  12. 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.

  13. [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.

  14. The 1982 El Chichon Eruption: The Birth of Volcanic Sulfur Dioxide Monitoring From Space

    NASA Astrophysics Data System (ADS)

    Krueger, A. J.; Krotkov, N.; Carn, S.

    2007-05-01

    The 1982 eruption of El Chichon inspired a new technique for monitoring volcanic clouds using satellites. Data from the Total Ozone Mapping Spectrometer (TOMS) instrument on the Nimbus-7 satellite were used to identify sulfur dioxide in the volcanic cloud and to map the extent of the cloud. For the first time the sulfur dioxide mass in even the largest explosive eruption plumes could be determined. The sizes of eruptions could be measured over 4 orders of magnitude. The position and area of volcanic clouds was determined as the clouds drifted globally with the winds over weeks of time after the eruption. The loss of sulfur dioxide by conversion to sulfate was observed. In addition, volcanic ash clouds were mapped using the TOMS aerosol data. Using sulfur dioxide as a tracer, magmatic eruptions could be discriminated from steam-driven, phreatic eruptions. The data from the El Chichon eruption are reanalyzed using the latest version of the TOMS instrument calibration (V8). They show the shearing of the eruption clouds in three weeks into a globe-circling band while still anchored over Mexico. The measured sulfur dioxide mass in the initial March 28 eruption was 1.6 Tg; a second eruption on April 3 produced 0.3 Tg more, and the climactic April 4 eruption added 5.6 Tg, for a cumulative total of 7.5 Tg, in substantial agreement with estimates from prior TOMS data versions. The TOMS derived sulfur dioxide mass is an order of magnitude higher than the petrologic estimate that is based on the lost sulfur in glass phases of the tephra. This "excess sulfur" brought rise to a reevaluation of the pre-eruptive magmatic processes in volcanoes and a better understanding of eruptions.

  15. 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

  16. Prevalence of prematurely lost primary teeth in 5–10-year-old children in Thamar city, Yemen: A cross-sectional study

    PubMed Central

    Murshid, Sakhr A.; Al-Labani, Mohammed A.; Aldhorae, Khalid A.; Rodis, Omar M. M.

    2016-01-01

    Objectives: The premature loss of primary teeth is a potential risk factor for poor arch length development. Adequate arch length is important to the progression of the permanent teeth. Poor arch length can lead to crowding, ectopic eruption, or impaction of these teeth. This study is designed to assess the prevalence of premature loss of primary teeth in the 5-10-year-old age group. Materials and Methods: The study group included 185 children, that is, 91 boys and 94 girls. The dental examination was conducted by an experienced examiner under sufficient artificial light. Data including patient age and missing teeth were collected. Descriptive statistics were applied for data analysis, and from the results, Chi-square tests were used at a level of significance of 5% (P < 0.05). Results: We observed a 40.54% prevalence of premature loss of primary teeth with no statistically significant difference between genders. The lower left primary second molar was the most commonly absent tooth in the dental arch (13.5%). Conclusion: The status of premature loss of primary teeth was high in the study group. Implementation of efficient educational and preventive programs to promote oral health would help children maintain a healthy primary dentition and eventually prevent the disturbances in the future development of normal occlusion. Early detection and management of the space problems associated with the early loss of primary teeth would help in reducing malocclusion problems. PMID:27652244

  17. Thermodynamics and fluid dynamics of effusive subglacial eruptions

    NASA Astrophysics Data System (ADS)

    Höskuldsson, A.; Sparks, R. S. J.

    We consider the thermodynamic and fluid dynamic processes that occur during subglacial effusive eruptions. Subglacial eruptions typically generate catastrophic floods (jökulhlaups) due to melting of ice by lava and generation of a large water cavity. We consider the heat transfer from basaltic and rhyolitic lava eruptions to the ice for typical ranges of magma discharge and geometry of subglacial lavas in Iceland. Our analysis shows that the heat flux out of cooling lava is large enough to sustain vigorous natural convection in the surrounding meltwater. In subglacial eruptions the temperature difference driving convection is in the range 10-100 °C. Average temperature of the meltwater must exceed 4 °C and is usually substantially greater. We calculate melting rates of the walls of the ice cavity in the range 1-40m/day, indicating that large subglacial lakes can form rapidly as observed in the 1918 eruption of Katla and the 1996 eruption of Gjálp fissure in Vatnajökull. The volume changes associated with subglacial eruptions can cause large pressure changes in the developing ice cavity. These pressure changes can be much larger than those associated with variation of bedrock and glacier surface topography. Previous models of water-cavity stability based on hydrostatic and equilibrium conditions may not be applicable to water cavities produced rapidly in volcanic eruptions. Energy released by cooling of basaltic lava at the temperature of 1200 °C results in a volume deficiency due to volume difference between ice and water, provided that heat exchange efficiency is greater than approximately 80%. A negative pressure change inhibits escape of water, allowing large cavities to build up. Rhyolitic eruptions and basaltic eruptions, with less than approximately 80% heat exchange efficiency, cause positive pressure changes promoting continual escape of meltwater. The pressure changes in the water cavity can cause surface deformation of the ice. Laboratory

  18. Automated detection of solar eruptions

    NASA Astrophysics Data System (ADS)

    Hurlburt, N.

    2015-12-01

    Observation of the solar atmosphere reveals a wide range of motions, from small scale jets and spicules to global-scale coronal mass ejections (CMEs). Identifying and characterizing these motions are essential to advancing our understanding of the drivers of space weather. Both automated and visual identifications are currently used in identifying Coronal Mass Ejections. To date, eruptions near the solar surface, which may be precursors to CMEs, have been identified primarily by visual inspection. Here we report on Eruption Patrol (EP): a software module that is designed to automatically identify eruptions from data collected by the Atmospheric Imaging Assembly on the Solar Dynamics Observatory (SDO/AIA). We describe the method underlying the module and compare its results to previous identifications found in the Heliophysics Event Knowledgebase. EP identifies eruptions events that are consistent with those found by human annotations, but in a significantly more consistent and quantitative manner. Eruptions are found to be distributed within 15 Mm of the solar surface. They possess peak speeds ranging from 4 to 100 km/s and display a power-law probability distribution over that range. These characteristics are consistent with previous observations of prominences.

  19. 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

  20. Improved pathologic teeth migration following gingivectomy in a case of idiopathic gingival fibromatosis.

    PubMed

    Seki, Keisuke; Sato, Shuichi; Asano, Yukhiro; Akutagawa, Hideyasu; Ito, Koichi

    2010-01-01

    A case is reported of a 20-year-old woman with generalized severe gingival overgrowth covering almost all of the teeth with diastemata, diagnosed as idiopathic gingival fibromatosis. After initial therapy, the patient underwent surgery consisting of a full-mouth internal beveled gingivectomy. Postoperatively, the maxillary anterior teeth spontaneously moved to almost optimal positions. Removing the cause by gingivectomy can lead to spontaneous correction of the pathologic tooth migration. With supportive periodontal treatment, the patient showed no recurrence of gingival enlargement or repositioning of the teeth at the 5-year follow-up.

  1. Intrusion and uprighting teeth for fixed prosthesis with temporary anchorage device.

    PubMed

    Palencar, Adrian J

    2012-01-01

    The mandibular first permanent molar is usually first to erupt around the age of six. Therefore, if the oral hygiene is not impeccable, it is usually also the first permanent tooth decayed in a child's mouth. A plethora of circumstances may lead to pulpal involvement, periapical pathosis, and endodontic treatment and in unfortunate situations, removal of this tooth. If this tooth is not replaced, or the extraction space is not retained for a considerable amount of time, the posterior occlusion will collapse. The most common occurrence is tipping of teeth in juxtaposition to the extraction site and extrusion of at least one opposing tooth. This article will describe efficient uprighting and intrusion of offending teeth prior to placement of fixed prosthesis. The author will explain the procedure step by step, first on acrylic models and then on the actual patient.

  2. 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.

  3. An alternative impression technique for mobile teeth.

    PubMed

    Lampraki, Evangelia; Chochlidakis, Konstantinos M; Rossopoulos, Evangelos; Ercoli, Carlo

    2016-10-01

    The impression technique described combines elastomeric impression materials and irreversible hydrocolloid to make an accurate preliminary impression of extremely mobile and misaligned teeth. Upon setting, the materials are removed from the mouth in 3 different directions and reassembled extraorally. This technique provides an alternative, easy, accurate, and safe way to make a preliminary impression of mobile, periodontally involved teeth.

  4. 21 CFR 872.5550 - Teething ring.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Teething ring. 872.5550 Section 872.5550 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES... divice intended for use by infants for medical purposes to soothe gums during the teething process....

  5. 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…

  6. 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

  7. Stochastic models for earthquake triggering of volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Bebbington, M. S.; Marzocchi, W.

    2011-05-01

    Many accounts, anecdotal and statistical, have noted a causal effect on volcanic eruptions from large, not too distant, earthquakes. Physical mechanisms have been proposed that explain how small static stress changes, or larger transient dynamic stress changes, can have observable effects on a volcano. While only ˜0.4% of eruptions appear to be directly triggered within a few days of an earthquake, these physical mechanisms also imply the possibility of delayed triggering. In the few regional studies conducted, data issues (selection bias and scarcity, inhomogeneity, and cleaning of data) have tended to obscure any clear signal. Using a perturbation technique, we first show that the Indonesian volcanic region possesses no statistically significant coupling for the region as a whole. We then augment a number of point process models for eruption onsets by a time-, distance-, and earthquake magnitude-dependent triggering term and apply this to the individual volcanoes. This method weighs both positive and negative (i.e., absence of eruptions following an earthquake) evidence of triggering. Of 35 volcanoes with at least three eruptions in the study region, seven (Marapi, Talang, Krakatau, Slamet, Ebulobo, Lewotobi, and Ruang) show statistical evidence of triggering over varying temporal and spatial scales, but only after the internal state of the volcano is accounted for. This confirms that triggering is fundamentally a property of the internal magma plumbing of the volcano in question and that any earthquake can potentially "advance the clock" toward a future eruption. This is further supported by the absence of any dependence on triggering of the eruption size.

  8. 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.

  9. Total electron content anomalies associated with global VEI4 + volcanic eruptions during 2002-2015

    NASA Astrophysics Data System (ADS)

    Li, Wang; Guo, Jinyun; Yue, Jianping; Shen, Yi; Yang, Yang

    2016-10-01

    In previous studies, little attention has been paid to the total electron content (TEC) anomalies preceding the volcanic eruption. We analyze the coupling relationship between volcanic eruption and TEC anomalies, and discuss the spatial distribution of TEC anomalies associated with volcanic geographical location. We utilize the global ionosphere map (GIM) data from the Center for Orbit Determination in Europe (CODE) to analyze TEC variations before the global volcanic eruptions indicated by VEI (Volcanic Explosivity Index) 4 + from 2002 to 2015 with the sliding interquartile range method. The results indicate the occurrence rate of TEC anomalies before great volcanic eruptions is related with the volcanic type and geographical position. The occurrence rate of TEC anomalies before stratovolcano and caldera eruptions is higher than that before shield and pyroclastic shield eruptions, and the occurrence rate of TEC anomalies has a descending trend from low latitudes to high latitudes. The TEC anomalies before the volcanic eruptions in low-mid latitudes are within the volcanic affected areas, but do not coincide with the volcanic foci. The corresponding TEC anomalies could be observed in the conjugated region, and all the TEC anomalies in the volcanic affected areas are usually close to bounds of equatorial anomaly zones. However, the TEC anomalies preceding these eruptions in high latitudes usually surround the volcano, and no TEC anomalies appear in the conjugated region. These conclusions have potential applications to the prediction of great volcanic eruptions in the future.

  10. 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.

  11. Seborrheic dermatitis-like eruption following interleukin-2 administration.

    PubMed

    Kawakami, Yoshio; Nakamura-Wakatsuki, Taeko; Yamamoto, Toshiyuki

    2010-09-15

    We describe a 72-year-old man suffering from renal cell carcinoma with lung metastases who developed scaly erythema on his face after the administration of recombinant interleukin-2 (rIL-2). A skin biopsy revealed intraepidermal and superficial perivascular infiltrate of mononuclear cells that were mainly composed of CD3 positive T-cells. There have been two cases of seborrheic dermatitis-like eruption induced by rIL-2. However, neither of them had histopathological evaluation. To our knowledge, this is the first case of seborrheic dermatitis-like eruption following rIL-2 administration whose histopathological investigations were performed.

  12. The 1631 eruption of Vesuvius

    NASA Astrophysics Data System (ADS)

    Rolandi, G.; Barrella, A. M.; Borrelli, A.

    1993-11-01

    Contemporary accounts of the violent eruption of Vesuvius in 1631 are reviewed, and recorded events are correlated with resulting volcanic deposits. Field study of the deposits in the proximal area revealed the presence of tephra falls, pyroclastic flows and lava, with subordinate surge deposits. A total volume of 1.1 km 3 (0.55 km 3 DRE) of phono-tephritic to phonolitic magma was ejected during 24 hours. The different magma compositions correspond with a transition from a lower, white, aphyric, highly vesiculated pumice (layer 1) to an upper, gray, crystal-rich, poorly vesiculated pumice (layer 3), showing reverse grading. Isopach and isopleth maps of the tephra-falls have been constructed to determine changes in the eruptive style and temporal evolution of the eruption column which reached a maximum height of 16 to 28 km. The recorded column height variations show a change in the mass discharge rate (8.9 × 10 6 kg/s to 8.2 × 10 7 kg/s) and the occurrence of pyroclastic flows during the deposition of the weakly vesiculated, dense pumice of the upper part of layer 3. Pyroclastic flows are crystal-rich and show St. Vincent-type features. The explosive phase demolished the upper part of the pre-existing cone, and debris flows invaded the southern side of the volcano. In the afternoon of December 17, 1631 an outbreak of lava flow from a southern lateral fracture system occurred, and effusion of lava continued up to midnight of December 18. Intermittent steam blasts continued to the end of December, when the eruption ended and Mount Vesuvius entered a solfataric phase. The earthquakes that had marked both the pre-eruptive and eruptive phases, continued, however, well into March 1632.

  13. 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

  14. 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.

  15. 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.

  16. 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

  17. A MODEL FOR MAGNETICALLY COUPLED SYMPATHETIC ERUPTIONS

    SciTech Connect

    Toeroek, T.; Titov, V. S.; Mikic, Z.; Linker, J. A.; Panasenco, O.; Reeves, K. K.; Velli, M.; De Toma, G.

    2011-10-01

    Sympathetic eruptions on the Sun have been observed for several decades, but the mechanisms by which one eruption can trigger another remain poorly understood. We present a three-dimensional MHD simulation that suggests two possible magnetic trigger mechanisms for sympathetic eruptions. We consider a configuration that contains two coronal flux ropes located within a pseudo-streamer and one rope located next to it. A sequence of eruptions is initiated by triggering the eruption of the flux rope next to the streamer. The expansion of the rope leads to two consecutive reconnection events, each of which triggers the eruption of a flux rope by removing a sufficient amount of overlying flux. The simulation qualitatively reproduces important aspects of the global sympathetic event on 2010 August 1 and provides a scenario for the so-called twin filament eruptions. The suggested mechanisms are also applicable for sympathetic eruptions occurring in other magnetic configurations.

  18. 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.

  19. The largest volcanic eruptions on Earth

    NASA Astrophysics Data System (ADS)

    Bryan, Scott; Peate, David; Ukstins Peate, Ingrid; Self, Stephen; Mawby, Michael; Jerram, Dougal; Marsh, Goonie

    2010-05-01

    Large igneous provinces (LIPs) are sites of the most frequently recurring, largest volume basaltic and silicic eruptions in Earth history. The magma volumes, eruptive mechanisms, frequency and associated aerosol emissions of these eruptions are critical for understanding any interpreted climate forcing and environmental change by LIPs. The largest volume (>1000 km3 dense rock equivalent) and magnitude (>M8) eruptions produce areally extensive (104-105 km2) basaltic lava flow fields and silicic ignimbrites and are the main building blocks of LIPs. Available information on the largest eruptive units are primarily from the Columbia River and Deccan provinces for the dimensions of flood basalt eruptions, and the Paraná-Etendeka and Afro-Arabian provinces for the silicic ignimbrite eruptions. In addition, three large-volume (675- 2,000 km3) silicic lava flows have also been mapped out in the Mesoproterozoic Gawler Range province (Australia), an interpreted LIP remnant. Magma volumes of >1000 km3 have also been emplaced as high-level basaltic and rhyolitic sills in LIPs, and may contribute substantial aerosol emissions through shallow degassing and crystallisation. The data sets indicate comparable eruption magnitudes between the basaltic and silicic eruptions, but due to considerable volumes residing as co-ignimbrite ash deposits, the current volume constraints for the silicic ignimbrite eruptions may be considerably underestimated. Magma composition thus appears to be no barrier to the volume of magma emitted during an individual eruption. Despite this general similarity in magnitude, flood basaltic and silicic eruptions are very different in terms of eruption style, duration, intensity, vent configuration, and emplacement style. Flood basaltic eruptions are dominantly effusive and Hawaiian-Strombolian in style, with magma discharge rates of ~107-108 kg s-1 producing dominantly compound pahoehoe lava flow fields. The major flood basalt eruption durations are most

  20. The largest volcanic eruptions on Earth

    NASA Astrophysics Data System (ADS)

    Ukstins Peate, I.; Bryan, S. E.; Peate, D. W.; Self, S.; Mawby, M.; Jerram, D. A.; Marsh, J.

    2010-12-01

    Large igneous provinces (LIPs) host the most frequently recurring, largest volume basaltic & silicic eruptions on Earth. Understanding magma volumes, eruptive mechanisms, frequency and aerosol emissions are critical to interpret climate forcing and environmental change. The largest volume (>1000 km3 dre) and magnitude (>M8) eruptions produce areally extensive (104-105 km2) basaltic flow fields and silicic ignimbrites that are the main building blocks of LIPs. Magma volumes >1000 km3 are also emplaced as high-level basaltic and rhyolitic sills in LIPs, and may contribute substantial aerosol emissions through shallow degassing and crystallization. Basaltic and silicic eruptions have comparable magnitudes, but silicic ignimbrite volumes may be significantly underestimated due to unrecognized and correlated, but voluminous co-ignimbrite ash deposits. Magma composition appears to be no barrier to individual eruption volume. Despite similar magnitudes, flood basaltic and silicic eruptions are very different in eruption mechanism, duration, intensity, vent configuration, and emplacement style. Flood basalts are dominantly effusive Hawaiian-Strombolian, with magma discharge rates of ~107-108 kg/s, and produce dominantly compound pahoehoe flow fields over eruption durations most likely >10 yrs. Some large-volume silicic lavas were emplaced by effusive and fissure eruptions, but discharge rates are unknown and may be up to an order of magnitude greater than those of flood basalt lavas for emplacement to be on realistic time scales (<10 years). Most silicic eruptions are moderately to highly explosive, producing co-current pyroclastic fountains (rarely Plinian) with discharge rates of 109-1011 kg/s that emplace welded to rheomorphic ignimbrites. Stratospheric ash and aerosol injections may be greater from co-ignimbrite ash clouds than eruption plumes. At present, durations for large-magnitude silicic eruptions are unconstrained. At discharge rates of 109 kg/s, equivalent to

  1. 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

  2. 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.

  3. Pressure wave generated by the Mount St. Helens eruption

    SciTech Connect

    Banister, J.B.

    1984-06-20

    Histories of the air pressure wave radiated from the eruption of Mount St. Helens on May 18, 1980, were calculated for two models of the eruption cloud expansion. The first considered the wave radiated from an accelerated plane surface, while the second examined the wave radiated from an expanding hemisphere. Two histories of eruption cloud motion based on photographs were used. Peak positive overpressures were about the same for these cloud motion histories of expansion into a hemisphere was assumed. If an accelerated planar source model was used, the peak positive pressures have again about the same value in east and west direction, but values are about half in the north and south direction. Observed peak overpressures at microbarograph stations are somewhat higher than the calculated with the most marked departures at the greater surface ranges. These observed overpressures may have been about half the correct values, however. Microbarograph records show a weaker rarefaction than calculated histories or none at all. This can be explained, in part, by a lack of a real motion coherence in the slowing eruption cloud. If it is also possible the net ash cloud volume increased considerably after its vertical growth ceased and weakened the negative phase as well as lengthening the positive phase.

  4. Orthodontics Align Crooked Teeth and Boost Self-Esteem

    MedlinePlus

    ... desktop! more... Orthodontics Align Crooked Teeth and Boost Self- esteem Article Chapters Orthodontics Align Crooked Teeth and Boost Self- esteem Orthodontics print full article print this chapter email ...

  5. Meprobamate-induced fixed drug eruption.

    PubMed

    Zaïem, Ahmed; Kaabi, Widd; Badri, Talel; Lakhoua, Ghozlane; Sahnoun, Rym; Kastalli, Sarrah; Daghfous, Riadh; Lakhal, Mohamed; El Aidli, Sihem

    2014-01-01

    Meprobamate is usually a safe drug prescribed for anxiety disorders. Fixed drug eruption (FDE) is an exceptional cutaneous adverse effect of this drug. We report a case of FDE induced by meprobamate with positive patch test. A 22-year-old woman was prescribed for depression meprobamate, aceprometazine, valpromide and lorazepam. On the second day of treatment, the patient presented red erythematous and pruriginous plaques in the limbs and the face. After stopping the previous treatment, the patient's lesions resolved completely within 3 weeks with residual pigmentation. One month later, patch tests were performed and were positive to meprobamate. Exceptional cases of FDE were reported in literature with meprobamate. None has reported the use of patch test to confirm the diagnosis.

  6. Romundina and the evolutionary origin of teeth

    PubMed Central

    Rücklin, Martin; Donoghue, Philip C. J.

    2015-01-01

    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. PMID:26109615

  7. 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.

  8. Eruptive viscosity and volcano morphology

    NASA Technical Reports Server (NTRS)

    Posin, Seth B.; Greeley, Ronald

    1988-01-01

    Terrestrial central volcanoes formed predominantly from lava flows were classified as shields, stratovolcanoes, and domes. Shield volcanoes tend to be large in areal extent, have convex slopes, and are characterized by their resemblance to inverted hellenic war shields. Stratovolcanoes have concave slopes, whereas domes are smaller and have gentle convex slopes near the vent that increase near the perimeter. In addition to these differences in morphology, several other variations were observed. The most important is composition: shield volcanoes tend to be basaltic, stratovolcanoes tend to be andesitic, and domes tend to be dacitic. However, important exceptions include Fuji, Pico, Mayon, Izalco, and Fuego which have stratovolcano morphologies but are composed of basaltic lavas. Similarly, Ribkwo is a Kenyan shield volcano composed of trachyte and Suswa and Kilombe are shields composed of phonolite. These exceptions indicate that eruptive conditions, rather than composition, may be the primary factors that determine volcano morphology. The objective of this study is to determine the relationships, if any, between eruptive conditions (viscosity, erupted volume, and effusion rate) and effusive volcano morphology. Moreover, it is the goal of this study to incorporate these relationships into a model to predict the eruptive conditions of extraterrestrial (Martian) volcanoes based on their morphology.

  9. Eruption conditions of spatter deposits

    NASA Astrophysics Data System (ADS)

    Rader, Erika; Geist, Dennis

    2015-10-01

    Spatter is an eruptive product that forms within a narrow range of thermal conditions: it must be hot enough to deform and agglutinate, but not so hot that clasts completely re-fuse and remobilize as clastogenic lava. This narrow thermal window of spatter-forming conditions allows for quantitative prediction of cooling rates and accumulation rates. Cooling and accumulation rates then provide information that enables estimates of eruption parameters for inaccessible and prehistoric deposits. High-temperature experiments conducted on basaltic scoria from Devil's Garden, Oregon have revealed the eruption temperature was ~ 1130 °C. The strength welds formed between experimental clasts is shown to depend on cooling rate. Natural samples are compared to the experimental samples by measuring tensile strength and welded area between clasts. The weld strength in natural deposits yields estimates of cooling rates that range between 2.5 °C and 48 °C/min, with the majority of the samples grouping between 7 °C and 14 °C/min. Thermal models based on these cooling rates yield spatter accumulation rates of 0.5-1.8 m/h in the Devil's Garden spatter deposits. We provide a general model for cooling and accumulation rates for spatter cones, ramparts, and hornitos, which allow estimation of the factors that control basaltic eruptive products.

  10. 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.

  11. Effective of diode laser on teeth enamel in the teeth whitening treatment

    NASA Astrophysics Data System (ADS)

    Klunboot, U.; Arayathanitkul, K.; Chitaree, R.; Emarat, N.

    2011-12-01

    This research purpose is to investigate the changing of teeth color and to study the surface of teeth after treatment by laser diode at different power densities for tooth whitening treatment. In the experiment, human-extracted teeth samples were divided into 7 groups of 6 teeth each. After that laser diode was irradiated to teeth, which were coated by 38% concentration of hydrogen peroxide, during for 20, 30 and 60 seconds at power densities of 10.9 and 52.1 W/cm2. The results of teeth color change were described by the CIEL*a*b* systems and the damage of teeth surface were investigated by scanning electron microscopy (SEM). The results showed that the power density of the laser diode could affect the whiteness of teeth. The high power density caused more luminous teeth than the low power density did, but on the other hand the high power density also caused damage to the teeth surface. Therefore, the laser diode at the low power densities has high efficiency for tooth whitening treatment and it has a potential for other clinical applications.

  12. Agenesis of Multiple Primary Teeth and

    PubMed Central

    Gokhale, Niraj; Sivakumar, N; Quadar, Md Akhil

    2013-01-01

    ABSTRACT Agenesis of multiple primary teeth is rare. A 6-year-old girl visited our department, in the absence of any other systemic abnormalities, on clinical and radiographic evaluation, it was revealed that she had only 6 primary teeth in her mouth. Maxillary and mandibular removable partial dentures were fabricated for prosthodontic rehabilitation. At the 6 months follow-up nutrition of the patient as well as self-confident appearance was improved. How to cite this article: Nirmala SVSG, Gokhale N, Sivakumar N, Quadar MA. Agenesis of Multiple Primary Teeth and Its Rehabilitation: A Case Report. Int J Clin Pediatr Dent 2013; 6(1):55-57. PMID:25206190

  13. 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.

  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. [Furcation lesions in deciduous teeth].

    PubMed

    Demars-Fremault, C; Pilipili Muhima, C

    1991-03-01

    The area of furcation of temporary molars constitutes a zone of exchanges and rearrangements relating to the evolution of the sub-adjacent permanent tooth. It is subjected to the eruption of the latter and to the physiological modifications of the temporary tooth. Moreover, this area is the site of above-mentioned inflammatory or infections conditions, maintained or aggravated by anatomical factors (accessory canals, thin pulpar floor, with little calcified dentine and broad tubuli), physiological factors (multiplication of accessory canals, decrease in the floor and migration of the epithelial attachment), endodontic factors (pulpal involvement and its complications) and periodontal factors (septum syndrome). The pathology of furcation is an evolving lesion. When discovered early it can be treated by endodontic therapy, while, in a later phase, it will require the extraction of the tooth. The assessment is made on the basis of a X-Ray examination which permits the temporary tooth to be situated in its stable or labile phase, the condition of the pulpal floor to be evaluated and the stage of sub-adjacent germ mineralisation to be estimated. A periodontal arrangement, by coronal reconstitution, conditions the reliability of the endodontic therapies.

  16. 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

  17. 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.

  18. The large volcanic eruptions at different latitude bands and patterns of winter temperature changes over China

    NASA Astrophysics Data System (ADS)

    Hao, Zhixin; Sun, Di

    2016-04-01

    Based on the chronology of 29 large volcanic eruptions events (Volcanic Explosivity Index≥4) since 1951 and gridded temperature dataset from China Meteorological Data Sharing Service System, we identified the patterns of winter temperature changes over China after the large volcanic eruptions, comparing with the mean temperature within the five years before, then we analyzed the related dynamic mechanisms of different patterns by NCEP reanalysis data and model output data from Community Earth System Model (CESM). The results showed that the winter temperature decreased more than 1°C in East China after volcanic eruptions on middle-lower latitudes and equatorial bands. After volcanic eruptions on different latitudes, the temperature spatial patterns were summarized as two types, which included that temperature was cooling centered on Northeast and warming in Tibets, and its opposite pattern. The first pattern was usually detected after tropical volcanic eruptions in spring/summer and it also appeared after volcanic eruptions on high latitudes in spring/autumn. After middle-lower latitude volcanic eruptions, the variation of geopotential height on 500hPa showed that the positive anomaly was existed at the East of Ural mountain, which caused the temperature decreased in Northwest , Central East and Southeast when east asian trough was intensified. After high latitudes volcanic eruptions, the zonal circulation was more obvious at middle latitudes, the cold air was not easy to transport,therefore winter temperature increased in China except for the Yangtze River Basin. The result of full forcing experiments by CESM showed that temperature decreased at most regions after large volcanic eruptions on equatorial /high bands, and troughs and wedges were developed on 500 hPa. The variation of geopotential height was nearly reversed after volcanic eruptions on high latitudes, only the temperature of Tibetan Plateau decreased. But how the variation of geopotential height

  19. The large volcanic eruptions at different latitude bands and patterns of winter temperature changes over China

    NASA Astrophysics Data System (ADS)

    Sun, D.; Hao, Z.; Zheng, J.

    2015-12-01

    Based on the chronology of 29 large volcanic eruptions events (Volcanic Explosivity Index≥4) since 1951 and gridded temperature dataset from China Meteorological Data Sharing Service System, we identified the patterns of winter temperature changes over China after the large volcanic eruptions, comparing with the mean temperature within the five years before, then we analyzed the related dynamic mechanisms of different patterns by NCEP reanalysis data and model output data from Community Earth System Model (CESM). The results showed that the winter temperature decreased more than 1°C in East China after volcanic eruptions on middle-lower latitudes and equatorial bands. After volcanic eruptions on different latitudes, the temperature spatial patterns were summarized as two types, which included that temperature was cooling centered on Northeast and warming in Tibets, and its opposite pattern. The first pattern was usually detected after equatorial volcanic eruptions in spring/summer and it also appeared after volcanic eruptions on high latitudes in spring/autumn. After middle-lower latitude volcanic eruptions, the variation of geopotential height on 500hPa showed that the positive anomaly was existed at the East of Ural mountain, which caused the temperature decreased in Northwest , Central East and Southeast when east asian trough was intensified. After high latitudes volcanic eruptions, the zonal circulation was more obvious at middle latitudes, the cold air was not easy to transport therefore winter temperature increased in China except for the Yangtze River Basin. The result of full forcing experiments by CESM showed that temperature decreased at most regions after large volcanic eruptions on equatorial /high bands, and troughs and wedges were developed on 500 hPa. The variation of geopotential height was nearly reversed after volcanic eruptions on high latitudes, only the temperature of Tibetan Plateau decreased. But how the variation of geopotential height

  20. 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.

  1. An assessment of microbial coronal leakage in teeth root filled with gutta-percha and three different sealers.

    PubMed

    Chailertvanitkul, P; Saunders, W P; Mackenzie, D

    1996-11-01

    The aim of this in vitro study was to determine the effect of three different root canal sealers on the bacterial penetration of obturated root canals. Eighty extracted human teeth with straight, single root canals were prepared using the modified double-flared technique with balanced force under copious irrigation until the master apical file was size 40. The teeth were divided randomly into experimental groups (60 teeth) and control groups (20 teeth). Twenty experimental teeth each were obturated by lateral condensation of cold gutta-percha with AH26, Apexit or Tubliseal EWT sealer. In the control groups, 10 teeth were obturated using the same technique with AH26, Apexit or Tubliseal EWT sealer. These teeth were completely sealed to serve as negative controls. The remaining 10 teeth were not obturated and served as positive controls. The root surface of each tooth, except the apical 2 mm, was sealed with nail varnish. The coronal part of each root canal was sealed with the cut end of a polypropylene tube and placed in a glass bottle containing sterile Todd-Hewitt Broth (THB). Aliquots of 0.5 ml of THB were injected into the polypropylene tube and the model system was centrifuged at 168 g. An innoculum of Streptococcus sanguis in THB was added to the tube at 5-day intervals and daily observations were made for bacterial growth in the apical reservoir for 90 days. All positive control teeth showed bacterial penetration within 24 h and negative control teeth remained uncontaminated throughout the test period. Leakage through the experimental teeth varied from 7 to 86 days. There was no statistically significant difference (P > 0.05) in leakage of the obturated canals between AH26, Apexit and Tubliseal EWT sealers.

  2. Replacement of Missing Anterior Teeth in a Patient with Chronic Mouth Breathing and Tongue Thrusting

    PubMed Central

    Haralur, Satheesh B.; Al-Qahtani, Ali Saad

    2013-01-01

    The loss of anterior teeth has serious functional, esthetic disabilities, in addition to compromising the patients' quality of life. Various etiologies can be attributed to the anterior tooth loss, including trauma, caries, and periodontal diseases. The chronic mouth breathing due to nasal adenoids is known to enhance the gingival and periodontal diseases. The dental literature proves the association of nasal breathing, tongue thrusting, and anterior open bite. Arch shape and tooth position are primarily determined by the equilibrium of the forces from tongue and perioral musculature. Increased force from tongue musculature in the tongue thrusting patient leads to flaring of anterior teeth, making them susceptible for periodontal and traumatic tooth loss. Replacement of the anterior teeth in this patient will also help in restoration of anterior guidance, which is critical for the health of temporomandibular joint, posterior teeth, and musculature. PMID:24490091

  3. Take Care of Your Teeth and Gums

    MedlinePlus

    ... En español Take Care of Your Teeth and Gums Browse Sections The Basics Overview Take Action! Brushing ... only in moderation. What causes tooth decay and gum disease? Plaque (“plak”) is a sticky substance that ...

  4. Bruxism (Teeth Grinding or Clenching) (For Parents)

    MedlinePlus

    ... to other family members because of the grinding sound. In some cases, nighttime grinding and clenching can wear down tooth enamel, chip teeth, increase temperature sensitivity, and cause severe facial pain and jaw ...

  5. 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.

  6. 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.

  7. New Insights into Basaltic Balloon Formation during Submarine Eruptions

    NASA Astrophysics Data System (ADS)

    Carey, S.; Kelly, J.; Rosi, M.; Pistolesi, M.; Marani, M.; Roman, C.; Croff Bell, K. L.

    2014-12-01

    Remotely operated vehicle (ROV) explorations in the area of the 1891 Foerstner submarine eruption (Pantelleria, Italy) during cruise NA-018 of the E/V Nautilus has provided the first examination of the vent site of a basaltic balloon-forming eruption. Ultra high-resolution bathymetric mapping defined a mound-like vent morphology in water depths of ~250 meter, constructed dominantly of highly vesicular scoriaceous fragments with minor pillow lava flows. The formation of floating basaltic balloons that reached the surface of the Strait of Sicily during the eruption is attributed to a hybrid Strombolian eruption mechanism that involved pre-concentration of volatiles into gas-rich portions of magma beneath the vent. An important difference of this Strombolian mechanism compared to its subaerial counterpart is the occurrence of buoyant magma discharge in the submarine environment caused by localized high gas contents. The added buoyancy flux modifies the fluid dynamic configuration of magma venting on the seafloor allowing for detachment of highly-inflated parcels of gas-rich magma. Some of these parcels contain large gas cavities that are enveloped in a partially quenched shell and maintain sufficient buoyancy to rise to the sea surface as a basaltic balloon. The majority of the vesicular magma maintains only partial positive buoyancy or negative buoyancy and is explosively fragmented to form large quantities of decimeter-scale fragments that accumulate close to the vent. Formation of the basaltic balloons is thus considered a somewhat accidental process that involves a subset of the total erupted volume of magma during the eruption. Suitable conditions for balloon formation include low magma viscosity, pre-concentration of gas, and moderate pressures (i.e.water depth). The dampening effect of seawater greatly reduces the dispersal of pyroclasts resulting in a mound-like vent morphology compared to subaerial scoria cones typically associated with Strombolian activity.

  8. 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

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. Influence of oral health behavior and sociodemographic factors on remaining teeth in Korean adults: 2010-2012 Korea national health and nutrition examination survey.

    PubMed

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

    2016-11-01

    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 loss than did

  14. Explosive volcanic eruptions, the El Nino-southern oscillation, and U.S. climate variability

    SciTech Connect

    Portman, D.A.

    1996-01-01

    A study was conducted to identify and separate possible signals of volcanic eruptions and of the El Nino Southern Oscillation (ENSO) in U.S. surface climate records. Anomalies of monthly mean surface air temperature and total precipitation taken from the U.S. Historical Climatology Network were composited (averaged) over years of major explosive volcanic eruptions, ENSO warm events, and ENSO cold events since the year 1900. It was assumed that volcanic eruptions and ENSO events occur independently of each other. All composite anomalies were assessed for significance with regard to several statistical and physical criteria. The composite ENSO-related anomalies were then subtracted from anomalies of temperature and precipitation associated with the volcanic eruptions. Removal of large magnitude and highly significant anomalies associated with the ENSO warm and cold events is found to facilitate detection of volcanic signals in monthly records of U.S. temperature and precipitation. Volcanic signals are strongly suggested east of the Continental Divide, for example, where positive monthly temperature anomalies exceeding 1{degrees}C occur during the first fall and winter after eruptions. Negative temperature anomalies occur west of the Continental Divide during the first winter and spring after eruptions and in the southern United States during the summer of the first post-eruption calendar year. Positive monthly precipitation anomalies exceeding 15 mm in magnitude are found in the southeastern United States during the first winter and spring after eruptions. Precipitation anomalies that are smaller in magnitude and yet significant, such as positive anomalies in the northwestern United States and negative anomalies in the central and eastern United States, are found during the summer of the first post-eruption calendar year. 62 refs., 9 figs., 4 tabs.

  15. Filament Eruption without Coronal Mass Ejection

    NASA Technical Reports Server (NTRS)

    Choudhary, Debi Prasad; Moore, Ronald L.

    2003-01-01

    We report characteristics of quiescent filament eruptions that were not associated with coronal mass ejections (CMEs). We examined 12 quiescent filament eruptions, each of which was located far from disk center (20.7 R(sub sun)) in diffuse remnant magnetic fields of decayed active regions, was well observed in full-disk movies in Ha and Fe XI, and had good coronagraph coverage. Of the 12 events, 9 were associated with CMEs and 3 were not. Even though the two kinds of eruption were indistinguishable in their magnetic setting and in the eruptive motion of the filament in the Ha movies, each of the CME-producing eruptions produced a two-ribbon flare in Ha and a coronal arcade and/or two-ribbon flare in Fe XII, and each of the non-CME-producing eruptions did not. From this result, and the appearance of the eruptive motion in the Fe XII movies, we conclude that the non-CME-associated filament eruptions are confined eruptions like the confined filament eruptions in active regions.

  16. 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.

  17. Infundibula of equine maxillary cheek teeth: Part 2: Morphological variations and pathological changes.

    PubMed

    Suske, A; Pöschke, A; Müller, P; Wöber, S; Staszyk, C

    2016-03-01

    Incomplete cemental filling of the infundibula of equine maxillary cheek teeth (CT) is a common feature. Depending on the extent of the defect, three stages of infundibular decay have been suggested. However, histomorphological criteria to identify non-pathological abnormalities and destructive changes have not been defined. Six hundred and eighty eight CT with no evidence of dental diseases and 55 diseased permanent, fully erupted maxillary CT were evaluated on a macroscopic level by assessing the occlusal surface and horizontal sections, including porphyrin assays to detect residual blood within the infundibular cementum. Selected specimens were investigated on a microscopic level using routine and immunohistological staining methods to identify possible routes for the spread of infectious agents from the infundibulum into the endodontic system. Infundibular cemental hypoplasia was defined as a non-pathological developmental abnormality and was detected in >50% of CT with no evidence of dental diseases and in >70% of diseased CT. The first molar (Triadan 09) showed the highest prevalence (75%) of infundibular cemental hypoplasia. The mesial infundibulum was more often affected than the distal infundibulum. Infundibular erosion was considered as the most appropriate term to describe destructive infundibular changes. Infundibular erosion was present in <6% of CT with no evidence of dental diseases, but was detected in >27% of diseased teeth, always accompanied by endodontic disease. This suggests that teeth affected by infundibular cemental hypoplasia are prone to destructive erosion, which possibly leads to endodontic disease. Morphological factors that supplement this ethological hypothesis were described. In 74% of infundibula residual blood was identified, although no vital blood vessels were detected. It is assumed that this content of blood remained in the ample infundibular cemental blood system after tooth eruption and creates a favorable environment for

  18. Forensic identification in teeth with caries.

    PubMed

    Alia-García, Esther; Parra-Pecharromán, David; Sánchez-Díaz, Ana; Mendez, Susy; Royuela, Ana; Gil-Alberdi, Laura; López-Palafox, Juan; del Campo, Rosa

    2015-12-01

    Human teeth are biological structures that resist extreme conditions thus becoming a useful source of DNA for human forensic identification purposes. When it is possible, forensic prefer only non-damaged teeth whereas those with cavities are usually rejected to avoid both external and internal bacterial contamination. Cavities are one of the most prevalent dental pathology and its incidence increases with ageing. The aim of this study was to validate the use of teeth with cavities for forensic identification. A total of 120 individual teeth from unrelated patients (60 healthy and 60 with cavities, respectively) extracted by a dentist as part of the normal process of treatment, were submitted for further analysis. Dental pulp was obtained after tooth fragmentation, complete DNA was extracted and the corresponding human identification profile was obtained by the AmpFlSTR® NGM SElect™ kit. Cariogenic microbiota was determined by PCR-DGGE with bacterial universal primers and bands were excised, re-amplified and sequenced. From the 120 dental pieces analyzed, a defined genetic profile was obtained in 81 (67.5%) of them, with no statistical differences between the healthy and the cavities-affected teeth. Statistical association between teeth status, DNA content and genetic profiles was not observed. Complex bacterial communities were only detected in the cavities group, being the Streptococcus/Enterococcus, and Lactobacillus genera the most represented. We conclude that teeth with cavities are as valid as healthy dental pieces for forensic human identification. Moreover, the severity of the cariogenic lesion as well as associated bacterial communities seems not to influence the establishment of human dental profiles.

  19. Compound odontoma associated with impacted maxillary central incisor dictates a need to be vigilant to canine eruption pattern: A 2-year follow-up

    PubMed Central

    Singla, Shilpy; Gupta, Sachin

    2016-01-01

    Canine deviation from its path of eruption is usually followed by either delayed or impaction of canine. One of the important and not so noticed reasons for canine displacement is formerly impacted central incisor. The difference in age of eruption of these two teeth is 4 years; however, the absence of maxillary incisor should be perceived with utmost conviction about impending canine displacement leading to its impaction as well. This case presents similar picture where composite, compound odontoma with respect to maxillary central incisor led to its impaction resulted in deviated path of eruption for erupting canine. This canine displacement to worsen prognosis ended up getting impacted if not dealt with cautiously in the later stages of occlusal development. PMID:27307685

  20. Comparison of hard tissue interrelationships at the cervical region of teeth based on tooth type and gender difference

    PubMed Central

    Astekar, Madhusudan; Kaur, Prabhpreet; Dhakar, Nidhi; Singh, Jappreet

    2014-01-01

    Context: Cementoenamel junction (CEJ) represents the anatomic limit between the crown and root surface. With advancing age and continuous eruption, this area becomes exposed in the oral media. Consequently, CEJ will be subjected to the action of various physical and chemical factors that might alter its morphology, with the cementum being affected in most cases. Aim: To identify the frequency of hard tissue interrelationships present at the CEJ in relation to different genders, positions and aspects of tooth using a light microscope. Materials and Methods: The cervical regions of 80 permanent teeth (40 male and 40 female), extracted for orthodontic or periodontal reasons, were analyzed after longitudinal ground sections were made in the mesio-distal plane. The CEJ of the prepared sections was then studied and their frequencies were categorized as: cementum overlapping enamel, enamel overlapping cementum, edge-to-edge relationship and the presence of gap junctions. Statistical Analysis: Chi-square test performed using SPSS 15 software. Results: Edge-to-edge contact of the cementum and enamel was most frequent, followed by gap junction and cementum overlapping the enamel, respectively. Chi-square test revealed no statistically significant differences with respect to the gender and tooth aspect, whereas the result was significant when the position of the tooth was studied. Conclusion: The observations of the study indicate a considerable morphological diversity in the anatomical pattern of CEJ. It can be concluded that the region should be protected against dentinal sensitivity, erosion, abrasion, abfraction and resorption, as it is more prone to cervical pathologies. PMID:25125914

  1. The effect of Andresen, Harvold, and Begg treatment on overbite and molar eruption.

    PubMed

    Ball, J V; Hunt, N P

    1991-02-01

    A retrospective cephalometric study was carried out to compare the vertical dental changes between patients treated with the Andresen (30), Harvold (19), or Begg (30) appliances, and an untreated control group (24). It was found that all three appliances successfully reduced the overbite although the reduction tended to be more stable with the functional appliances. Overbite was reduced by a combination of factors which varied according to the appliance used, but included lower incisor intrusion or restraint, molar eruption, vertical growth of the face and lower incisor proclination in the functional groups. Relapse appeared to be primarily due to continued lower incisor eruption, retroclination of these teeth, and forward rotation of the mandible with continued growth.

  2. [Prevention of the eruption of an upper later incisor by a compound odontoma. Case report].

    PubMed

    Vlcek, Daniel; Reichart, Peter A; Bosshardt, Dieter D; Sleiter, Roberto; Bornstein, Michael M

    2012-01-01

    Odontomas are the most common odontogenic tumours. They are considered as hamartomas - a local tissue malformation without autonomous growth potential - and are non-neoplastic. Clinically and histopathologically, compound and complex odontomas can be differentiated. Compound odontomas consist of a varying number of tooth-like structures and histology show dental tissues in an orderly pattern. Most often compound odontomas are diagnosed in young patients in the anterior maxilla. Patients are rarely complaining of symptoms and they are usually diagnosed during routine radiographic examinations or due to late eruption of permanent or persistence of deciduous teeth. The following case report presents a disturbed eruption of a lateral right incisor of the maxilla in a 8-year old female patient. Clinical, radiological and histopathological characteristics of this lesion will be discussed as well as therapy and follow-up.

  3. At what depths do magma-water eruptions breach the surface?

    NASA Astrophysics Data System (ADS)

    Wendel, JoAnna

    2014-09-01

    When magma ascends upward in the Earth's crust, it can react violently with groundwater, leading to underground explosions or even full-fledged eruptions. If they breach the surface, these phreatomagmatic eruptions leave debris that falls concentrically around the crater or cone. Previously, researchers have sought to determine the depth within the vent from which the eruption originated by looking at the types of ejected rocks and their original positions beneath the volcanoes, but Valentine et al. found that these two factors are not necessarily directly related.

  4. The 2006 lava dome eruption of Merapi Volcano (Indonesia): Detailed analysis using MODIS TIR

    NASA Astrophysics Data System (ADS)

    Carr, Brett B.; Clarke, Amanda B.; Vanderkluysen, Loÿc

    2016-02-01

    Merapi is one of Indonesia's most active and dangerous volcanoes. Prior to the 2010 VEI 4 eruption, activity at Merapi during the 20th century was characterized by the growth and collapse of a series of lava domes. Periods of very slow growth were punctuated by short episodes of increased eruption rates characterized by dome collapse-generated pyroclastic density currents (PDCs). An eruptive event of this type occurred in May-June, 2006. For effusive eruptions such as this, detailed extrusion rate records are important for understanding the processes driving the eruption and the hazards presented by the eruption. We use thermal infrared (TIR) images from the Moderate Resolution Imaging Spectrometer (MODIS) instrument on NASA's Aqua and Terra satellites to estimate extrusion rates at Merapi Volcano during the 2006 eruption using the method of Harris and Ripepe (2007). We compile a set of 75 nighttime MODIS images of the eruptive period to produce a detailed time series of thermal radiance and extrusion rate that reveal multiple phases of the 2006 eruption. These data closely correspond to the published ground-based observational record and improve observation density and detail during the eruption sequence. Furthermore, additional analysis of radiance values for thermal anomalies in Band 21 (λ = 3.959 μm) of MODIS images results in a new framework for detecting different styles of activity. We successfully discriminate among slow dome growth, rapid dome growth, and PDC-producing dome collapse. We also demonstrate a positive correlation between PDC frequency and extrusion rate, and provide evidence that extrusion rate can increase in response to external events such as dome collapses or tectonic earthquakes. This study represents a new method of documenting volcanic activity that can be applied to other similar volcanic systems.

  5. 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.

  6. Forced eruption without orthodontic brackets using fiber reinforced composite prostheses: a case report.

    PubMed

    Mete, J J; Dange, S P; Khalikar, A N; Vaidya, S P

    2012-09-01

    Maintenance of periodontal health is one of the most important factors governing success of the restoration and longevity of teeth. For proper maintenance of periodontal health, the biologic width functions as a protective barrier against the entrance of microorganisms in to the internal medium of the periodontal ligament and osseous connective tissue. This clinical case describes a technique to reestablish the biologic width surrounding a fractured central incisor by forced eruption without orthodontic brackets, using fibre reinforced composite prostheses. Main advantages of using fibre reinforced composite prostheses are aesthetic maintenance during the treatment period, no need for occlusal adjustments, simplicity, low cost, and stability.

  7. Multivariate Analyses of Small Theropod Dinosaur Teeth and Implications for Paleoecological Turnover through Time

    PubMed Central

    Larson, Derek W.; Currie, Philip J.

    2013-01-01

    Isolated small theropod teeth are abundant in vertebrate microfossil assemblages, and are frequently used in studies of species diversity in ancient ecosystems. However, determining the taxonomic affinities of these teeth is problematic due to an absence of associated diagnostic skeletal material. Species such as Dromaeosaurus albertensis, Richardoestesia gilmorei, and Saurornitholestes langstoni are known from skeletal remains that have been recovered exclusively from the Dinosaur Park Formation (Campanian). It is therefore likely that teeth from different formations widely disparate in age or geographic position are not referable to these species. Tooth taxa without any associated skeletal material, such as Paronychodon lacustris and Richardoestesia isosceles, have also been identified from multiple localities of disparate ages throughout the Late Cretaceous. To address this problem, a dataset of measurements of 1183 small theropod teeth (the most specimen-rich theropod tooth dataset ever constructed) from North America ranging in age from Santonian through Maastrichtian were analyzed using multivariate statistical methods: canonical variate analysis, pairwise discriminant function analysis, and multivariate analysis of variance. The results indicate that teeth referred to the same taxon from different formations are often quantitatively distinct. In contrast, isolated teeth found in time equivalent formations are not quantitatively distinguishable from each other. These results support the hypothesis that small theropod taxa, like other dinosaurs in the Late Cretaceous, tend to be exclusive to discrete host formations. The methods outlined have great potential for future studies of isolated teeth worldwide, and may be the most useful non-destructive technique known of extracting the most data possible from isolated and fragmentary specimens. The ability to accurately assess species diversity and turnover through time based on isolated teeth will help illuminate

  8. Solid modeling of fossil small mammal teeth

    NASA Astrophysics Data System (ADS)

    Marschallinger, Robert; Hofmann, Peter; Daxner-Höck, Gudrun; Ketcham, Richard A.

    2011-09-01

    This paper presents an approach to create solid models of fossil small mammal teeth using a combination of microcomputed tomography, object based image analysis and voxel modeling. Small mammal teeth, because of their durability, are widely found in Cenozioc sediments the world over and play a key role in stratigraphy as well as in researching the rapid evolution and the paleogeographic spreading of small mammals. Recent advances in microcomputed tomography make this non-destructive analysis method an ideal data source for high-resolution 3D models of fossil small animal teeth. To derive internally consistent solid models of such fossils from micro-CT imagery, we propose a combination of 3D object based image analysis and solid modeling. Incorporating paleontological expert knowledge in the image processing cycle, object based image analysis yields topologically consistent image stacks classified by the main tooth components—enamel, dentine and pulp. Forwarding these data to a voxel modeling system, they can be quantitatively analyzed in an unprecedented manner: going beyond the possibilities of the state-of-art surface models, solid models are capable of unambiguously portraying the entire object volume—teeth can be peeled by material properties, subvolumes can be extracted and automatically analyzed by Boolean operations. The proposed method, which can be flexibly extended to handle a range of paleontological and geological micro-objects, is demonstrated with two typical fossil small mammal teeth.

  9. Translucency measurements in teeth and dental materials

    NASA Astrophysics Data System (ADS)

    Rawicz, Andrew H.; Melnyk, Ivan; Kowalski, Pawel

    2003-06-01

    Exact color matching of dental restorative materials to vital teeth is a difficult task. There are several reasons for this difficulty and they will be elaborated upon in the presentation. One of the most important reasons is the fact that teeth, as well as dental restorative materials are translucent, and thus the color impression is a product of light scattering, back scattering, transmission, and spectral modifications inside of these objects. Classic colorimetry is insufficient to provide an exact color match. Additional information about the translucency factor of the considered object (material and geometry) is necessary to provide full reproducibility. Translucency has a direct effect on perceived brightness. In this article we describe the TransluDent, a complementary product to ColorDent, which measures translucency of teeth and dental materials. TransluDent determines translucency by measuring light transmitted through an object and light scattered inside of the object. The translucency measurements were performed on two groups of subjects. One group consisted of people in their twenties and the second group of subjects was in fifties. For comparison several sets of dental shade-guides were also tested. The great discrepancy in translucency factor between human teeth and popular on the market shades may explain difficulty in color matching of dental restorative materials to teeth.

  10. Fixed drug eruption by etoricoxib confirmed by patch test*

    PubMed Central

    de Sousa, Aline Soares; Cardoso, José Carlos; Gouveia, Miguel Pinto; Gameiro, Ana Rita; Teixeira, Vera Barreto; Gonçalo, Maria

    2016-01-01

    Non-steroidal, anti-inflammatory drugs, followed by antibiotics, are the main causes of fixed drug eruption. They provoke one or several round erythematous or bullous lesions that recur in the same place after taking the causative medication. A positive patch test on residual, lesional skin can replace satisfactorily oral reintroduction. We describe the case of a 74-year-old woman with numerous, rounded, erythematous lesions on the trunk and recurrent blistering on the fifth right-hand finger, which developed a few hours after taking etoricoxib. Lesional patch testing with etoricoxib was positive and reproduced the typical pattern of a fixed drug eruption upon histopathology. We emphasize the specific reactivity of the etoricoxib patch test, and the capacity to reproduce the histologic pattern of the reaction. PMID:27828643

  11. Fixed drug eruption by etoricoxib confirmed by patch test.

    PubMed

    Sousa, Aline Soares de; Cardoso, José Carlos; Gouveia, Miguel Pinto; Gameiro, Ana Rita; Teixeira, Vera Barreto; Gonçalo, Maria

    2016-01-01

    Non-steroidal, anti-inflammatory drugs, followed by antibiotics, are the main causes of fixed drug eruption. They provoke one or several round erythematous or bullous lesions that recur in the same place after taking the causative medication. A positive patch test on residual, lesional skin can replace satisfactorily oral reintroduction. We describe the case of a 74-year-old woman with numerous, rounded, erythematous lesions on the trunk and recurrent blistering on the fifth right-hand finger, which developed a few hours after taking etoricoxib. Lesional patch testing with etoricoxib was positive and reproduced the typical pattern of a fixed drug eruption upon histopathology. We emphasize the specific reactivity of the etoricoxib patch test, and the capacity to reproduce the histologic pattern of the reaction.

  12. The Latest on Volcanic Eruptions and Climate

    NASA Astrophysics Data System (ADS)

    Robock, Alan

    2013-08-01

    What was the largest volcanic eruption on Earth since the historic Mount Pinatubo eruption on 15 June 1991? Was the Toba super­eruption 74,000 years ago—the largest in the past 100,000 years—responsible for a human genetic bottleneck or a 1000-year-long glacial advance? What role did small volcanic eruptions play in the reduced global warming of the past decade? What caused the Little Ice Age? Was the April 2010 Eyjafjallajökull eruption in Iceland important for climate change? What do volcanic eruptions teach us about new ideas on geoengineering and nuclear winter? These are some of the questions that have been answered since the review article by Robock [2000]. Reviews by Forster et al. [2007] and Timmreck [2012] go into some of these topics in much greater detail.

  13. 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

  14. 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)].

  15. Post-menopausal cyclic eruptions: autoimmune progesterone dermatitis.

    PubMed

    Bolaji, I I; O'Dwyer, E M

    1992-11-19

    Two cases of autoimmune progesterone dermatitis (AIPD) are reported. The patients developed a recurrent eruption, primarily on the extremities after receiving oral oestrogen/progesterone replacement for the treatment of climacteric symptoms. The diagnosis was confirmed in one of the cases who had intradermal progesterone injection producing an early positive reaction. One case required transient prednisolone therapy and both eventually resolved completely. Aetiological postulates are discussed.

  16. Mars: Review and analysis of volcanic eruption theory and relationships to observed landforms

    NASA Astrophysics Data System (ADS)

    Wilson, Lionel; Head, James W., III

    1994-08-01

    We present a theoretical treatment of the ascent, emplacement, and eruption of magma on Mars. Because of the lower gravity, fluid convective motions and crystal settling processes driven by positive and negative buoyancy forces, as well as overall diapiric ascent rates, will be slower on Mars than on Earth, permitting larger diapirs to ascend to shallower depths. Martian environmental conditions operate to modulate the various eruption styles and the morphology and morphometry of resulting landforms, providing new insight into several volcanological problems.

  17. Winter warming from large volcanic eruptions

    SciTech Connect

    Robock, A.; Mao, J.

    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.

  18. 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.

  19. Tornados and Transverse Oscillations during Prominence Eruption

    NASA Astrophysics Data System (ADS)

    Banerjee, Dipankar; Chandrashekhar, K.; Morton, Richard; Pant, Vaibhav; Datta, Ajanta

    2016-07-01

    We report and analyse different phases of a prominence eruption. The winding-unwinding of two footpoints and a tornado like swirling motion is studied. The prominence eruption is observed by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO). This prominence eruption is associated with a CME at a central principal angle of 340 degree, according to the SOHO/LASCO CME catalogue. We can observe the prominence threads and the time distance maps reveal that the loop threads are entangled. We also study the transverse oscillations in the threads. Swirling motions after the eruptions are also quantified and its possible link with the CME kinematics is also studied

  20. Solar Eruption and Local Magnetic Parameters

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

    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) 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.

  1. Extreme strength observed in limpet teeth

    PubMed Central

    Barber, Asa H.; Lu, Dun; Pugno, Nicola M.

    2015-01-01

    The teeth of limpets exploit distinctive composite nanostructures consisting of high volume fractions of reinforcing goethite nanofibres within a softer protein phase to provide mechanical integrity when rasping over rock surfaces during feeding. The tensile strength of discrete volumes of limpet tooth material measured using in situ atomic force microscopy was found to range from 3.0 to 6.5 GPa and was independent of sample size. These observations highlight an absolute material tensile strength that is the highest recorded for a biological material, outperforming the high strength of spider silk currently considered to be the strongest natural material, and approaching values comparable to those of the strongest man-made fibres. This considerable tensile strength of limpet teeth is attributed to a high mineral volume fraction of reinforcing goethite nanofibres with diameters below a defect-controlled critical size, suggesting that natural design in limpet teeth is optimized towards theoretical strength limits. PMID:25694539

  2. What Generated the Eruptive Tremor During the Bardarbunga Eruption, Iceland?

    NASA Astrophysics Data System (ADS)

    Eibl, Eva P. S.; Bean, Christopher J.; Vogfjörd, Kristin S.; Jónsdóttir, Ingibjörg; Höskuldsson, Armann; Þórðarson, Þorvaldur

    2016-04-01

    The Bárðarbunga eruption in Iceland 2014/15 led to the formation of a 85 km2 big lavafield and the extrusion of ~1.5 km3 of magma. The eruption initially started for 4 hours on August 29th. It stopped but restarted on the same fissure on August 31st. We installed a seismic array on August 30th. Harmonic tremor was seen on August 31st consistent with the visual opening of the fissure and continued through February 2015. The harmonic tremor with most energy from 0.8-1.5 Hz is remarkably stable over 6 months but 3 characteristic features occur from time to time: (i) Stronger harmonic tremor bursts in the same frequency range, (ii) Stronger non-harmonic bursts with energy up to 5 Hz and (iii) Step like increases or decreases in the tremor amplitude. Seemingly uncorrelated the array results show (iv) three very stable tremor directions until mid October and (v) tremor sources moving by up to 9 km in 4 days. We compare these five seismic observations with the features of the growing lavafield and discuss the relative importance of possible tremor sources such as: a resonating conduit, boiling magma in the vent, a resonating lavafield, interactions at the edges of the lavafield and inflation of the lavafield.

  3. ESR dating of teeth from Brazilian megafauna

    NASA Astrophysics Data System (ADS)

    Oliveira, L. C.; Kinoshita, A.; Barreto, A. M. F.; Figueiredo, A. M.; Silva, J. L. L.; Baffa, O.

    2010-11-01

    The study of radiation defects created in biomaterials, such as bone and teeth, can be used in dating with importance to palaeontology and archaeology. Two Stegomastodon teeth (AL1 and AL2) from north-eastern Brazilian megafauna were studied by electron spin resonance (ESR) spectroscopy. The samples were collected in Fazenda Ovo da Ema, (913349 / 3714965) UTM, Alagoas state, Brazil. The dating of these samples can contribute to the better knowledge of megafauna presence in this region as well as to the events associated to the extinction of these species.

  4. Evidence for the Climatic Impact of the 1600 Eruption of Huaynaputina Volcano, Peru

    NASA Astrophysics Data System (ADS)

    Lippman, J.; Verosub, K. L.

    2006-12-01

    The global climatic impact of the 1815 eruption of Tambora volcano has been well-documented. However, any assessment of the risk from Tambora-type eruptions requires information about the frequency of such events. Briffa et al. (1998) have suggested on the basis of tree-ring data that the most severe short-term Northern Hemisphere cooling event of the past 600 years occurred in 1601, which is the year following the 1600 eruption of Huaynaputina volcano in Peru. The estimated Volcanic Explosivity Index for this eruption is 6, which is comparable to that of Tambora. We have been looking for other climate proxies that could provide information about the nature and extent of the cooling that might have been associated with the eruption of Huaynaputina in 1600, including records of speleothem thickness, first flowering of plants, beginning of wine harvests, coral growth, thickness of ice layers, dust veil indices, glacial positions, additional tree-ring records and historical documents. Although the signal is difficult to discern, there seems to be good evidence that the effects of the 1600 eruption of Huaynaputina volcano are comparable to those of the 1815 eruption of Tambora. This result is important because it documents that Tambora was not an isolated occurrence in the Holocene and supports the idea that such events might occur with a return frequency of as little as 200 years. Thus, any realistic discussion of the societal risk from natural perils needs to include the possibility of volcanically-induced global climate change.

  5. Evaluation of Apical Microleakage in Open Apex Teeth Using MTA Apical Plug in Different Sessions

    PubMed Central

    Yazdizadeh, Mohammad; Bouzarjomehri, Zeinab; Khalighinejad, Navid; Sadri, Leyli

    2013-01-01

    Aim. To compare microleakage of apexification using MTA in one or two sessions. Materials and Methods. 88 single rooted teeth were prepared and divided into two groups then received MTA apical plug. In the first group, the teeth were immersed in normal saline for 24 hours and then backfilled with guttapercha and AH26 sealer. In the second group, the teeth were obturated immediately after receiving apical plug. Four positive and four negative controls were selected. All specimens were placed in 1% methylene blue and decalcified in 5% nitric acid and finally were placed in methyl salicylate until getting transparent. All teeth were visualized for assessment of dye penetration under stereo dissecting microscope. Results. 36 and 35 teeth showed dye leakage in the first and second groups. Dye penetration into the entire canal length was confirmed in the positive control group, and in the negative control group no dye penetration was seen. Mean dye penetration in the first and second group was 5813 and 9152 μm. t-test revealed a significant difference between dye penetrations of two groups (P < 0.05). Conclusion. MTA requires adequate time for setting in the presence of the moisture, and final obturation should be delayed until final setting of MTA. PMID:24282642

  6. 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.

  7. 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

  8. Growth and development of permanent teeth germ of transplacental Yu-Cheng babies in Taiwan

    SciTech Connect

    Lan, Shoujen; Yen, Yeayin; Ko, Yingchin; Chen, Engrin )

    1989-06-01

    This paper is intended to present a study of transplacental Yu-Cheng babies in Taiwan. The focus of the study is to demonstrate how a contaminated food source can affect the growth and development of permanent teeth germ in children. A sporadic outbreak of a peculiar skin disease was reported in Japan in October of 1968. An epidemiological study revealed the outbreak of this disease was caused by contaminated Kanemi rice oil. This episode of rice oil poisoned with polychlorinated biphenyls (PCB) was the first reported outbreak of PCB poisoning in the world. A second episode occurred in central Taiwan eleven years after the Japanese episode. Registered data from the Taiwan Provincial Government Health Department reported 1,843 cases in 1980. Of this group, more than 800 women were child-bearing age and most of these women would or soon would be married and pregnant. The offsprings of these women were in danger, because it has been proven that PCB intoxication could affect the fetus. These babies, only contaminated through the placenta, are called PCB transplacental Yusho babies in Japan and PCB transplacental Yu-Cheng babies in Taiwan. Babies with PCB poisoning could have Fetal PCB syndrome (FPS) and may have retarded eruption of permanent teeth and other anomalies such as reduced numbers of teeth and abnormal shaped roots. The study of transplacental Yu-Cheng babies is an important public health issue for Taiwan. Although there may be other issues, this study focuses only on the growth and development of permanent teeth of those babies affected by PCB transplacental contamination.

  9. 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.

  10. 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..

  11. 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.

  12. Textural and geochemical constraints on eruptive style of the 79AD eruption at Vesuvius

    NASA Astrophysics Data System (ADS)

    Balcone-Boissard, Hélène; Boudon, Georges; Villemant, Benoît.

    2010-05-01

    The 79AD eruption of Vesuvius, also known as the "Pompeii eruption", is the reference for one of the explosive eruptive styles, the plinian-type eruption. The eruption involved H2O-rich phonolitic magmas and is commonly divided into three phases: an initial phreatomagmatic phase, followed by a plinian event which produced a thick pumice fallout deposit and a final phase that was dominated by numerous column-collapse events. During the plinian phase, a first white pumice fallout was produced from a high steady eruptive column, followed by a grey pumice fallout originated by an oscillatory eruptive column with several partial column collapse events. This study focuses on the pumice fallout deposits, sampled in a proximal thick section, at the Terzigno quarry, 6 km southeast of the present crater. In order to constrain the degassing processes and the eruptive dynamics, major element compositions, residual volatile contents (H2O, Cl) and textural characteristics (vesicularity and microcrystallinity) were studied. A previous study that we performed on the pre-eruptive Cl content has shown that Cl may be used as an indicator of magma saturation with Cl-rich fluids and of pre-eruptive pressures. Cl contents measured in melt inclusions show that only the white pumice and the upper part of the grey pumice magma were H2O saturated prior eruption. Large variations in residual volatile contents exist between the different eruptive units and textural features strongly differ between white and grey pumice clasts but also within the grey pumice clasts. The degassing processes were thus highly heterogeneous: the white pumice eruptive units represent a typical closed-system degassing evolution whereas the first grey pumice one, stored in the same pre-eruptive saturation conditions, follows a particular open-system degassing evolution. Here we propose a new model of the 79AD eruption where pre-eruptive conditions (H2O saturation, magma temperature and viscosity) are the critical

  13. Rapid forced eruption: a case report and review of forced eruption techniques.

    PubMed

    Durham, Timothy M; Goddard, Thomas; Morrison, Scott

    2004-01-01

    This article reviews the infrequently utilized treatment method of forced eruption and how it can serve as an alternative to the sacrifice of the natural root system. Forced eruption can preserve the natural root system and related periodontal architecture, resulting in years of additional service for the patient. It also can maintain adjacent tooth structure while retaining the option for future implant reconstruction. Given the reported success of forced eruption, the technique requires greater attention and increased application among dentists. A case of forced eruption in the anterior maxilla utilizing a removable device is described. An overview of forced eruption technique also is provided.

  14. Sterilisation of extracted human teeth for educational use.

    PubMed

    Kumar, M; Sequeira, P S; Peter, S; Bhat, G K

    2005-10-01

    Sixty intact, non-carious and unrestored teeth extracted due to periodontal disease were used to determine the most effective method of sterilisation. The teeth were divided into six groups, each containing 10 teeth. Group 1 teeth were immersed in 10% formalin for seven days, group 2 teeth were immersed in 3% hydrogen peroxide for seven days, group 3 teeth were immersed in 2.6% sodium hypochlorite for seven days, group 4 teeth were boiled in water at 100 degrees C for 20 minutes, group 5 teeth were autoclaved at 121 degrees C at 15 lbs psi for 30 minutes, and group 6 teeth were immersed in normal saline for seven days. After the treatment, the teeth were individually inoculated into trypticase soy broth and incubated for 48 hours. A questionnaire survey was also conducted to determine the awareness of dental students regarding infection due to extracted human teeth and the common disinfection/sterilisation methods used. Autoclaving at 121 degrees C, 15 lbs psi for 30 minutes and immersion in 10% formalin for seven days were effective in disinfecting/sterilising extracted human teeth. Chemicals such as 2.6% sodium hypochlorite, 3% hydrogen peroxide and boiling in water were not effective. The results indicate that autoclaving for 30 minutes or immersion in 10% formalin for seven days could be effectively used for disinfection/sterilisation of extracted human teeth.

  15. Premature loss of primary anterior teeth due to trauma--potential short- and long-term sequelae.

    PubMed

    Holan, Gideon; Needleman, Howard L

    2014-04-01

    Traumatic dental injuries (TDIs) can result in the premature loss of primary anterior teeth due to an immediate avulsion, extraction later after the injury because of poor prognosis or late complications, or early exfoliation. There are a number of potential considerations or sequelae as a result of this premature loss that have been cited in the dental literature, which include esthetics, quality of life, eating, speech development, arch integrity (space loss), development and eruption of the permanent successors, and development of oral habits. This article provides a comprehensive review of the dental literature on the possible consequences of premature loss of maxillary primary incisors following TDI.

  16. Dynamic characterization of teeth by laser vibrometry

    NASA Astrophysics Data System (ADS)

    Castellini, Paolo; Miglietta, G.; Revel, Gian M.; Scalise, Lorenzo

    1998-06-01

    The use of air compressed, high rotational velocity drill and of ultrasound devices in the dentist practice can cause pain for the patient and damage to the tooth structure. The authors in this paper have investigated the possible cause of these problems: the vibrations caused by the drill exciting the tooth. Particular attention has been dedicated to the frequency behavior of teeth, in order to individualize their frequency resonances. A method for the investigation of human teeth dynamic response, in terms of natural frequencies and modal shapes has been proposed. Very short laser pulses have been used to excite teeth vibrations and a scanning laser doppler vibrometer to measure the dynamic response. An assessment of the amplitude of the characteristics of the excitation has been done using the theory of the impulse response function in such a way as to calculate the frequency response of the teeth. The results measured have been compared. Results permit to extract information extremely useful for the design of devices used in the dentist practice.

  17. Hierarchical structure and biomineralization in cricket teeth

    NASA Astrophysics Data System (ADS)

    Xing, Xue-Qing; Gong, Yu; Cai, Quan; Mo, Guang; Du, Rong; Chen, Zhong-Jun; Wu, Zhong-Hua

    2013-02-01

    The cricket is a truculent insect with stiff and sharp teeth as a fighting weapon. The structure and possible biomineralization of cricket teeth are always interesting. Synchrotron radiation X-ray fluorescence, X-ray diffraction, and small angle X-ray scattering techniques were used to probe the element distribution, possible crystalline structures and size distribution of scatterers in cricket teeth. A scanning electron microscope was used to observe the nanoscaled structure. The results demonstrate that Zn is the main heavy element in cricket teeth. The surface of a cricket tooth has a crystalline compound like ZnFe2(AsO4)2(OH)2(H2O)4. The interior of the tooth has a crystalline compound like ZnCl2, which is from the biomineralization. The ZnCl2-like biomineral forms nanoscaled microfibrils and their axial direction points towards the top of the tooth cusp. The microfibrils aggregate randomly into intermediate filaments, forming a hierarchical structure. A sketch map of the cricket tooth cusp is proposed and a detailed discussion is given in this paper.

  18. Treatment rationale of fractured posterior teeth.

    PubMed

    Silvestri, A R; Singh, I

    1978-11-01

    The four types of fractures most frequently encountered in posterior teeth--obliquely directed complete fractures, vertically directed complete fractures, obliquely directed incomplete fractures, and vertically directed incomplete fractures--have been described. A detailed treatment approach for each type has been presented.

  19. Elephant teeth from the atlantic continental shelf.

    PubMed

    Whitmore, F C; Emery, K O; Cooke, H B; Swift, D J

    1967-06-16

    Teeth of mastodons and mammoths have been recovered by fishermen from at least 40 sites on the continental shelf as deep as 120 meters. Also present are submerged shorelines, peat deposits, lagoonal shells, anz relict sands. Evidently elephants and other large mammals ranged this region during the glacial stage of low sea level of the last 25,000 years.

  20. Teeth: Among Nature's Most Durable Biocomposites

    NASA Astrophysics Data System (ADS)

    Lawn, Brian R.; Lee, James J.-W.; Chai, Herzl

    2010-08-01

    This paper addresses the durability of natural teeth from a materials perspective. Teeth are depicted as smart biocomposites, highly resistant to cumulative deformation and fracture. Favorable morphological features of teeth at both macroscopic and microscopic levels contribute to an innate damage tolerance. Damage modes are activated readily within the brittle enamel coat but are contained from spreading catastrophically into the vulnerable tooth interior in sustained occlusal loading. Although tooth enamel contains a multitude of microstructural defects that can act as sources of fracture, substantial overloads are required to drive any developing cracks to ultimate failure—nature's strategy is to contain damage rather than avoid it. Tests on model glass-shell systems simulating the basic elements of the tooth enamel/dentin layer structure help to identify important damage modes. Fracture and deformation mechanics provide a basis for analyzing critical conditions for each mode, in terms of characteristic tooth dimensions and materials properties. Comparative tests on extracted human and animal teeth confirm the validity of the model test approach and point to new research directions. Implications in biomechanics, especially as they relate to dentistry and anthropology, are outlined.

  1. Elephant teeth from the atlantic continental shelf

    USGS Publications Warehouse

    Whitmore, F.C.; Emery, K.O.; Cooke, H.B.S.; Swift, D.J.P.

    1967-01-01

    Teeth of mastodons and mastodons have been recovered by fishermen from at least 40 sites on the continental shelf as deep as 120 meters. Also present are submerged shorelines, peat deposits, lagoonal shells, and relict sands. Evidently elephants and other large mammals ranged this region during the glacial stage of low sea level of the last 25.000 years.

  2. Simulation of a flow around biting teeth

    NASA Astrophysics Data System (ADS)

    Narusawa, Hideaki; Yamamoto, Eriko; Kuwahara, Kunio

    2008-11-01

    We simulated a flow around biting teeth. The decayed tooth is a disease that a majority of people are annoyed. These are often generated from a deep groove at occlusal surface. It is known that a person who bites well doesn't suffer from a decayed tooth easily. Biting forces reach as much as 60 kg/cm^2 by an adult male, and when chewing, upper and lower teeth approach to bite by those forces. The crushed food mixed with saliva becomes high viscosity fluid, and is pushed out of ditches of teeth in the direction of the cheek or the tongue. Teeth with complex three dimension curved surface are thought to form venturi at this time, and to generate big pressure partially. An excellent dental articulation will possibly help a natural generation of a flow to remove dental plaque, i.e. the cause of the decayed tooth. Moreover, the relation of this flow with the destruction of the filled metal or the polymer is doubted. In this research, we try to clarify the pressure distributions by this flow generation as well as its dynamics when chewing. One of our goals is to enable an objective design of the shape of the dental fillings and the artificial tooth. Tooth has a very small uneven ground and a bluff body. In this case, to calculate a computational numerical simulation to solve the Navier-Stokes equations three dimension Cartesian coordinate system is employed.

  3. Modification Of Gear Teeth To Reduce Vibrations

    NASA Technical Reports Server (NTRS)

    Townsend, Dennis P.; Oswald, Fred B.; Lin, Hsiang Hsi

    1990-01-01

    Computer simulations yield data useful in designing for low noise. Effects of modifications in shape of gear teeth upon static transmission error and dynamic loading of gears now analyzed systematically. Design curves generated by conducting numerical simulations of dynamic effects at successive incremental modifications of gear systems operated at various applied loads. Modifications that result in minimum dynamic effect determined from design curves.

  4. Computing Contact Stresses In Gear Teeth

    NASA Technical Reports Server (NTRS)

    Oswald, Fred B.; Somprakit, Paisan; Huston, Ronald L.

    1995-01-01

    Improved method of computing contact stresses in gear teeth accounts for complicating effects like those of static and sliding friction. Provides iterative procedure for determination of contact region and nodal contact forces along with contact stresses. Method based on equations and computational procedure incorporating these effects routinely.

  5. Do We Need National Standards with Teeth?

    ERIC Educational Resources Information Center

    Usiskin, Zalman

    2007-01-01

    The author, director of the University of Chicago School Mathematics Project, tackles the following question: Should the United States have national standards with teeth, that is, a single set of standards tied to assessments and agreed to by the states? Proponents advance five main arguments for implementing such a standard. In his rebuttal, the…

  6. How to Care for Your Baby's Teeth

    MedlinePlus

    ... can use a wet washcloth or gauze to clean your baby’s teeth and gums. Start using a soft baby toothbrush and a small dab of toothpaste that does not have fluoride in it when your baby is between 1 ...

  7. Modeling eruptive coronal magnetohydrodynamic systems with FLUX

    NASA Astrophysics Data System (ADS)

    Rachmeler, L. A.

    In this dissertation I explore solar coronal energetic eruptions in the context of magnetic reconnection, which is commonly thought to be a required trigger mechanism for solar eruptions. Reconnection is difficult to directly observe in the corona, and current numerical methods cannot model reconnectionless control cases. Thus, it is not possible to determine if reconnection is a necessary component of these eruptions. I have executed multiple controlled simulations to determine the importance of reconnection for initiation and evolution of several eruptive systems using FLUX, a numerical model that uses the comparatively new fluxon technique. I describe two types of eruptions modeled with FLUX: a metastable confined flux rope theory for coronal mass ejection (CME) initiation, and symmetrically twisted coronal jets in a uniform vertical background field. In the former, I identified an ideal magnetohydrodynamic (MHD) instability that allows metastable twisted flux rope systems to suddenly lose stability and erupt even in the absence of reconnection, contradicting previous conjecture. The CME result is in contrast to the azimuthally symmetric coronal jet initiation model, where jet-like behavior does not manifest without reconnection. My work has demonstrated that some of the observed eruptive phenomena may be triggered by non-reconnective means such as ideal MHD instabilities, and that magnetic reconnection is not a required element in all coronal eruptions.

  8. Large erupting complex odontoma: a case report.

    PubMed

    Vengal, Manoj; Arora, Honey; Ghosh, Sujoy; Pai, Keerthilatha M

    2007-03-01

    Odontomas are the most common odontogenic tumours. They are usually asymptomatic and are often discovered during routine radiography. We report a case of a large erupting complex odontoma that caused pain, infection and facial asymmetry. This case is significant as there are few reports of complex odontoma erupting in the oral cavity.

  9. Recovery From Giant Eruptions in Massive Stars

    NASA Astrophysics Data System (ADS)

    Kashi, A.; Davidson, K.; Humphreys, R. M.

    2015-12-01

    We perform radiation hydrodynamic simulations to study how very massive stars recover from giant eruptions. The post eruption star experience strong mass loss due to strong winds, driven by radial pulsations in the star*s interior, that operate by the κ-mechanism. The mass loss history obtained in our simulations resembles η Car*s history.

  10. Pathological studies of cheek teeth apical infections in the horse: 2. Quantitative measurements in normal equine dentine.

    PubMed

    Shaw, D J; Dacre, I T; Dixon, P M

    2008-12-01

    Measurements of primary, regular and irregular secondary dentine and pulp dimensions were made on transverse, sub-occlusal and mid-tooth sections, of 40 maxillary and 42 mandibular control equine cheek teeth (CT) of different ages. Maxillary and mandibular CT primary dentine in different age groups had a mean thickness of 922-1,065 microm and 1099-1,179 microm, respectively, on the lateral aspects, and 1,574-2,035 microm and 1155-1,330 microm, respectively, on the medial aspects of pulp horns. Surprisingly, some increase in thickness was found in some mandibular CT primary enamel in the first few years following eruption. Regular secondary dentine thickness increased with age, for example at mid-tooth level in mandibular CT from 124 microm at 3 years dental age to 290 microm at >7 years dental age on the lateral aspect of pulp horns, and from 166 microm to 509 microm on the medial aspects of pulp horns, indicating a deposition rate of 0.5-10 microm/day. This type of dentine was thicker sub-occlusally than in the mid-tooth region. Maxillary dentinal dimensions showed a similar age-related increase in thickness. Maxillary CT dentine was significantly thicker (72% in primary, 43% in regular secondary dentine) on the medial compared to the lateral aspects of pulp horns, but mandibular CT dentine was just 15% and 14% thicker in primary and regular secondary dentine thickness, respectively, on the their medial as compared to their lateral aspects. Dentinal and pulp dimensions varied between individual pulp horns, Triadan tooth position, and dental age, with complex interactions between these variables for some parameters.

  11. 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.

  12. 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.

  13. [Calcium hydroxide in the treatment of traumatized teeth].

    PubMed

    Cvek, M

    1989-09-01

    Calcium hydroxide is used in the treatment of different traumatized teeth. New concepts about the effects of calcium hydroxide on vital pulps and immature non vital teeth are developed. Some clinical techniques and their results are described.

  14. Oxalic acid in saliva, teeth and tooth tartar.

    PubMed

    Wahl, R; Kallee, E

    1994-11-01

    Oxalic acid was determined in human saliva, teeth, tartar, and in animal teeth. Saliva from dentally healthy male subjects contained 0.10 +/- 0.09 mmol/l (n = 41) and those of dentally healthy female subjects 0.18 +/- 0.17 mmol/l (n = 40). Oxalic acid in tartar from 16 patients was 3.3 +/- 1.2 mmol/kg tartar. In human teeth, oxalic acid was 1.0 +/- 0.3 mmol/kg in milk teeth (n = 12) and 0.9 +/- 0.6 mmol/kg in permanent teeth (n = 60). Human teeth were sorted into age groups and into molars, incisors and premolars. In animal teeth, oxalic acid content varied widely. The formed calcium oxalate is proposed to be a 'physiological' protective mechanism for teeth.

  15. The large superpredators' teeth from Middle Triassic of Poland

    NASA Astrophysics Data System (ADS)

    Surmik, Dawid; Brachaniec, Tomasz

    2013-09-01

    An unusual large teeth, finding from time to time in marine sediments of Muschelkalk, Silesia, Poland indicate the superpredators occurrence. According to size and morphological features the teeth are similar to archosaurs or giant marine reptiles.

  16. 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.

  17. 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

  18. Radiographic visualization of magma dynamics in an erupting volcano.

    PubMed

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

    2014-03-10

    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.

  19. Loss of teeth and enamel in tetrapods: fossil record, genetic data and morphological adaptations.

    PubMed

    Davit-Béal, Tiphaine; Tucker, Abigail S; Sire, Jean-Yves

    2009-04-01

    Since their recruitment in the oral cavity, approximately 450 million years ago, teeth have been subjected to strong selective constraints due to the crucial role that they play in species survival. It is therefore quite surprising that the ability to develop functional teeth has subsequently been lost several times, independently, in various lineages. In this review, we concentrate our attention on tetrapods, the only vertebrate lineage in which several clades lack functional teeth from birth to adulthood. Indeed, in other lineages, teeth can be absent in adults but be functionally present in larvae and juveniles, can be absent in the oral cavity but exist in the pharyngeal region, or can develop on the upper jaw but be absent on the lower jaw. Here, we analyse the current data on toothless (edentate) tetrapod taxa, including information available on enamel-less species. Firstly, we provide an analysis of the dispersed and fragmentary morphological data published on the various living taxa concerned (and their extinct relatives) with the aim of tracing the origin of tooth or enamel loss, i.e. toads in Lissamphibia, turtles and birds in Sauropsida, and baleen whales, pangolins, anteaters, sloths, armadillos and aardvark in Mammalia. Secondly, we present current hypotheses on the genetic basis of tooth loss in the chicken and thirdly, we try to answer the question of how these taxa have survived tooth loss given the crucial importance of this tool. The loss of teeth (or only enamel) in all of these taxa was not lethal because it was always preceded in evolution by the pre-adaptation of a secondary tool (beak, baleens, elongated adhesive tongues or hypselodonty) useful for improving efficiency in food uptake. The positive selection of such secondary tools would have led to relaxed functional constraints on teeth and would have later compensated for the loss of teeth. These hypotheses raise numerous questions that will hopefully be answered in the near future.

  20. Loss of teeth and enamel in tetrapods: fossil record, genetic data and morphological adaptations

    PubMed Central

    Davit-Béal, Tiphaine; Tucker, Abigail S; Sire, Jean-Yves

    2009-01-01

    Since their recruitment in the oral cavity, approximately 450 million years ago, teeth have been subjected to strong selective constraints due to the crucial role that they play in species survival. It is therefore quite surprising that the ability to develop functional teeth has subsequently been lost several times, independently, in various lineages. In this review, we concentrate our attention on tetrapods, the only vertebrate lineage in which several clades lack functional teeth from birth to adulthood. Indeed, in other lineages, teeth can be absent in adults but be functionally present in larvae and juveniles, can be absent in the oral cavity but exist in the pharyngeal region, or can develop on the upper jaw but be absent on the lower jaw. Here, we analyse the current data on toothless (edentate) tetrapod taxa, including information available on enamel-less species. Firstly, we provide an analysis of the dispersed and fragmentary morphological data published on the various living taxa concerned (and their extinct relatives) with the aim of tracing the origin of tooth or enamel loss, i.e. toads in Lissamphibia, turtles and birds in Sauropsida, and baleen whales, pangolins, anteaters, sloths, armadillos and aardvark in Mammalia. Secondly, we present current hypotheses on the genetic basis of tooth loss in the chicken and thirdly, we try to answer the question of how these taxa have survived tooth loss given the crucial importance of this tool. The loss of teeth (or only enamel) in all of these taxa was not lethal because it was always preceded in evolution by the pre-adaptation of a secondary tool (beak, baleens, elongated adhesive tongues or hypselodonty) useful for improving efficiency in food uptake. The positive selection of such secondary tools would have led to relaxed functional constraints on teeth and would have later compensated for the loss of teeth. These hypotheses raise numerous questions that will hopefully be answered in the near future. PMID

  1. The response of winter Pacific North American pattern to strong volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Liu, Zhongfang; Yoshimura, Kei; Buenning, Nikolaus H.; Jian, Zhimin; Zhao, Liang

    2016-07-01

    The impact of volcanic eruptions on large-scale atmospheric circulation patterns has been well studied, but very little effort has been made on relating the response of Pacific North American (PNA) pattern to strong volcanic eruptions. Here we investigate the response of winter PNA to the largest volcanic eruptions using three different reanalysis datasets. We demonstrate a significant positive PNA circulation response to strong volcanic forcing in the first winter following the eruptions. This circulation pattern is associated with enhanced southwesterly winds advecting warm air from the tropical/subtropical Pacific into northwestern North America and leads to a significant warming in the region. However, no significant PNA signal is found for the second post-eruption winter. The PNA responses to volcanic forcing depend partly upon the modulation of the El Niño Southern Oscillation (ENSO) events. When the ENSO influence is linearly removed, this positive PNA signal is still robust during the first post-eruption winter, albeit with slightly decreased magnitude and significance. Our findings provide new evidence for volcanic forcing of the Pacific and North American climates. The results presented here may contribute to deconvolving modern and past continental-scale climate changes over North America.

  2. 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

  3. Estimates of mass eruption rates in Icelandic eruptions 1913-2015

    NASA Astrophysics Data System (ADS)

    Tumi Gudmundsson, Magnus; Dürig, Tobias; Larsen, Gudrún

    2016-04-01

    In the period from 1913 to 2015 about 35 eruptions occurred in Iceland, although some uncertainty exists about the number of the smallest events, particularly within the ice covered regions. For the smaller events in the earlier part of the period, only order of magnitude estimates of mass eruption rates (MER) are possible, based on the approximate amount of erupted products, duration of eruption, and information on eruption plume height in some cases. After 1947 estimates are more reliable. This is not least due to the detailed observations and interpretations of Sigurdur Thorarinsson and co-workers until the early 1980s. After 1980, various observations and instrumental data, e.g. on plume height, coupled with detailed mapping by several workers of tephra fallout and lava flow extent provide a good basis for MER estimates. The most frequent events are explosive eruptions producing tephra, often basaltic phreatomagmatic eruptions. A contributing factor to the large number of explosive eruptions is unusually frequent eruptions in Hekla since 1947. Eruptions under glaciers are also common, while a majority of these become explosive as they break through the ice. For the initially subglacial eruptions ice melting rates provide the best estimate of the MER in the first and usually most powerful phase. If the whole data set is considered, the magma volumes erupted in a single eruption span three orders of magnitude, ˜0.001 km3 to 1 km3. The range of intensity is similar, with the smallest Krafla or Askja events having maximum mass eruption rates (MER) of order 10-100 tonnes/second while the most powerful ones (Hekla 1947 and Katla 1918) had MER ˜50,000 tonnes/second (˜5 x 107 kg/s). All the events with the highest MER were explosive, including Katla 1918 where initial subglacial melting caused the largest volcanogenic flood observed since the 18th century. The period 1913-2015 had no events that belong to the class of the largest observed eruptions in Iceland. In

  4. The longevity of lava dome eruptions

    NASA Astrophysics Data System (ADS)

    Wolpert, Robert L.; Ogburn, Sarah E.; Calder, Eliza S.

    2016-02-01

    Understanding the duration of past, ongoing, and future volcanic eruptions is an important scientific goal and a key societal need. We present a new methodology for forecasting the duration of ongoing and future lava dome eruptions based on a database (DomeHaz) recently compiled by the authors. The database includes duration and composition for 177 such eruptions, with "eruption" defined as the period encompassing individual episodes of dome growth along with associated quiescent periods during which extrusion pauses but unrest continues. In a key finding, we show that probability distributions for dome eruption durations are both heavy tailed and composition dependent. We construct objective Bayesian statistical models featuring heavy-tailed Generalized Pareto distributions with composition-specific parameters to make forecasts about the durations of new and ongoing eruptions that depend on both eruption duration to date and composition. Our Bayesian predictive distributions reflect both uncertainty about model parameter values (epistemic uncertainty) and the natural variability of the geologic processes (aleatoric uncertainty). The results are illustrated by presenting likely trajectories for 14 dome-building eruptions ongoing in 2015. Full representation of the uncertainty is presented for two key eruptions, Soufriére Hills Volcano in Montserrat (10-139 years, median 35 years) and Sinabung, Indonesia (1-17 years, median 4 years). Uncertainties are high but, importantly, quantifiable. This work provides for the first time a quantitative and transferable method and rationale on which to base long-term planning decisions for lava dome-forming volcanoes, with wide potential use and transferability to forecasts of other types of eruptions and other adverse events across the geohazard spectrum.

  5. Tailored order: the mesocrystalline nature of sea urchin teeth.

    PubMed

    Goetz, Andreas J; Griesshaber, E; Abel, R; Fehr, Th; Ruthensteiner, B; Schmahl, W W

    2014-09-01

    We investigated the pattern of crystal co-orientation at different length scales, together with variations in chemical composition and nanomechanical properties in the teeth of the modern sea urchin Paracentrotus lividus with electron backscatter diffraction (EBSD), electron probe microanalysis, energy-dispersive X-ray spectroscopy and nanoindentation testing. Modern sea urchin teeth are Mg-dominated calcite composite materials. They are distinctly harder than inorganically precipitated calcite. Some parts exceed even the hardness of dolomite. The teeth show a structuring of their mechanical properties that can be correlated to variations in major element chemical composition, such that their hardness is positively correlated to their magnesium contents. Mg/Ca ratio in Paracentrotus lividus varies between 10 and 26mol.%. Nanohardness of the tooth scatters between 3.5 and >8GPa compared to values of 3.0±0.2, 7.3±0.1 and 9.2±0.9GPa measured on the (104) planes of inorganic calcite, dolomite and magnesite, respectively. High-resolution EBSD shows that major structural units and subunits of the tooth of Paracentrotus lividus are tilted to each other by ∼3-5° and 1-2°, respectively. This indicates that the tooth is not a single crystal. With EBSD we can show that the tooth of the sea urchin Paracentrotus lividus is a hierarchically assembled biological mesocrystal with a mosaic texture. In comparison to the misorientation spread of 0.5° of calcite grown from solution, misorientation in the tooth varies between 2° and 4°. Thus, the self-sharpening feature of the tooth is enabled by a close interplay of its highly evolved micro- to nanostructure, structural unit size variations with a varying degree of crystal orientation, chemical structuring of the mineral component and a gradation of incorporated organic polymers.

  6. Natal teeth: Case report and review of literature

    PubMed Central

    Rao, Roopa S; Mathad, Sudha V

    2009-01-01

    The presence of teeth at birth or within a month post-delivery is a rare condition. A newborn, a 2 days old female, with two mandibular incisor natal teeth was examined. The teeth were mobile and were extracted because of the fear of aspiration and refusal to feed. The purpose of this report is to review the literature related to natal teeth epidemiology and discuss their possible etiology and treatment. PMID:21886998

  7. Bovine teeth as substitute for human teeth in dental research: a review of literature.

    PubMed

    Yassen, Ghaeth H; Platt, Jeffrey A; Hara, Anderson T

    2011-09-01

    The aim of this paper was to review in vitro and in situ studies that directly compared the use of bovine teeth as a substitute for human teeth in dental experiments. A PubMed search was conducted for papers published from 1953 to December 30, 2010 using the following keywords: "human bovine enamel" or "human bovine dentin" or "human bovine teeth". The abstracts of the studies resulting from the keyword search were read, and all papers that compared human and bovine teeth were fully read. Only original articles written in English and directly comparing human and bovine substrates were included in the review. The search was supplemented by manual searches of the reference lists from each identified paper. Out of 76 studies initially selected, 68 fulfilled the selection criteria for inclusion. The studies covered seven categories: dental morphology, chemical composition, physical properties, dental caries, dental erosion/abrasion, bonding/adhesive strength, and marginal microleakage. Inconsistent data exist regarding whether bovine teeth can be considered an appropriate substitute for human teeth in dental research. Morphological, chemical compostion and physical property differences between the two substrates must be considered when interpreting results obtained from any experiment using bovine tooth substrate.

  8. Late Miocene teeth from Middle Awash, Ethiopia, and early hominid dental evolution.

    PubMed

    Haile-Selassie, Yohannes; Suwa, Gen; White, Tim D

    2004-03-05

    Late Miocene fossil hominid teeth recovered from Ethiopia's Middle Awash are assigned to Ardipithecus kadabba. Their primitive morphology and wear pattern demonstrate that A. kadabba is distinct from Ardipithecus ramidus. These fossils suggest that the last common ancestor of apes and humans had a functionally honing canine-third premolar complex. Comparison with teeth of Sahelanthropus and Orrorin, the two other named late Miocene hominid genera, implies that these putative taxa are very similar to A. kadabba. It is therefore premature to posit extensive late Miocene hominid diversity on the basis of currently available samples.

  9. Explosive Super-eruptions: Problems and Prejudices

    NASA Astrophysics Data System (ADS)

    Self, S.

    2010-12-01

    A super-eruption is defined as one with a magma yield > 10^15 kg (magnitude (M) 8). The term has mainly been applied to large-scale, caldera and ignimbrite-forming explosive eruptions, but it can be applied to all eruptions that released > 10^15 kg of magma. For effusive volcanism, evidence suggests that individual eruptions of this size ( > ~ 370 km^3 of typical basalt or > 450 km^3 of rhyolite flood lava) arise only during periods of LIP formation. The super-eruption concept raises interesting questions about genesis and storage of magmas that feed these vast events. Deposits of major explosive eruptions are Plinian fallout, ignimbrite sheets, and co-ignimbrite ash fall. Based on earlier suggestions and evidence, widespread outflow ignimbrite (O), co-ignimbrite ash (A), and inter-caldera ignimbrite (I) are all major components of the total super-eruption deposit and may tend towards being subequal. In super-eruption deposits, the reported volume of vent-derived Plinian eruption column fallout is often a minor component of the total volume, yet in several cases (Oruanui, Taupo, 26 ka ago, M 8.1; Bishop Tuff, 760 ka, M 8.2; Bandelier (Otowi) Tuff, 1.6 Ma, M8) it is now recognized that vent-derived columns persisted for most of the eruption. Thus, distally, the ash-fall derived from co-ignimbrite ash clouds may be mixed with contemporaneous fallout from a vertical column. Some major ignimbrites have no reported associated Plinian deposit; the huge Young Toba Tuff (YTT, 74 ka, M 8.8) is a significant example. However, the very widespread Toba ash-fall deposit constitutes ~ 40 % of the total mass of magma erupted and is presumed to be co-ignimbrite. Timing of the onset of column collapse probably controls whether a recognizable Plinian deposit is laid down. All super-eruptions probably produce extensive fallout deposits, and this is generally of vent-derived and pyroclastic-flow-derived origin. Establishing the relationships between large-scale ignimbrites and their

  10. 21 CFR 872.6475 - Heat source for bleaching teeth.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Heat source for bleaching teeth. 872.6475 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6475 Heat source for bleaching teeth. (a) Identification. A heat source for bleaching teeth is an AC-powered device that consists of...

  11. 21 CFR 872.6475 - Heat source for bleaching teeth.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Heat source for bleaching teeth. 872.6475 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6475 Heat source for bleaching teeth. (a) Identification. A heat source for bleaching teeth is an AC-powered device that consists of...

  12. [Extraction of 56 horizontally impacted teeth using dental implanter].

    PubMed

    Zhang, Yan-ping; Liang, Na

    2005-06-01

    50 cases, totally 56 horizontally impacted teeth were extracted using dental implanter to remove the alveolar bone. Another 56 horizontally impacted teeth were extracted using high speed turbine.It's concluded that is a safe and easy way using the dental implanter to remove the horizontally impacted teeth, and the reaction and the complications could be minimized.

  13. An evaluation of factors associated with persistent primary teeth.

    PubMed

    Aktan, Ali Murat; Kara, Isa; Sener, Ismail; Bereket, Cihan; Celik, Salih; Kirtay, Mustafa; Ciftçi, Mehmet Ertugrul; Arici, Nursel

    2012-04-01

    The aim of the present study was to investigate the reasons for the persistence of primary teeth and also use panoramic radiography to determine the characteristics of persistence teeth. Four-hundred and twenty-six panoramic radiographies, which diagnosed one or more retained primary teeth, were selected from 100,577 panoramic radiographic image files from nine clinics and six different cities in Turkey. The selected radiographies were evaluated to determine the reasons for the persistence of primary teeth; furthermore, this study analyzed the characteristics of the retained primary teeth including tooth type, number, location, and root resorption, and whether, or not, the primary teeth showed evidence of pathological conditions, such as periodontal problems, caries, ankylosis, infra-occlusions, or tipping of the adjacent permanent teeth. Six hundred and seventy-seven retained primary teeth were determined in 426 patients (148 males and 278 females). Retained primary teeth were found most frequently in the mandible rather than the maxilla and the left side was more frequently affected than the right side. Level 1 was found as a most frequently encountered root resorption level. Within the limitation of the present study, the most common type of persistent primary teeth seen on the dental arch were mandibular primary second molars, followed by maxillary primary canines. The most frequent reason for the persistence was the congenital absence of successors to the primary teeth, followed by impaction of the successor teeth.

  14. 21 CFR 872.6475 - Heat source for bleaching teeth.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6475 Heat source for bleaching teeth. (a) Identification. A heat source for bleaching teeth is an AC-powered device that consists of a... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Heat source for bleaching teeth. 872.6475...

  15. 21 CFR 872.6475 - Heat source for bleaching teeth.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6475 Heat source for bleaching teeth. (a) Identification. A heat source for bleaching teeth is an AC-powered device that consists of a... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Heat source for bleaching teeth. 872.6475...

  16. 21 CFR 872.6475 - Heat source for bleaching teeth.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6475 Heat source for bleaching teeth. (a) Identification. A heat source for bleaching teeth is an AC-powered device that consists of a... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Heat source for bleaching teeth. 872.6475...

  17. 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

  18. 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

  19. Effect of Four Different Media on Periodontal Ligament Cells Viability of Dry- Stored Dog Teeth

    PubMed Central

    Moazzami, Fariborz; Asheghi, Bahar; Sahebi, Safoura

    2017-01-01

    Statement of the Problem: The maintenance of viable periodontal ligament cells is the most important issue in the long-term preservation of avulsed teeth. Purpose: The aim of this study was to assess aloe vera as a new storage media in maintaining the cell viability of dry-stored teeth in comparison with soy milk, Hank`s balanced salt solution (HBSS), and milk. Materials and Method: Twenty one extracted dog premolar teeth were dried for 30 minutes and stored in soy milk, HBSS, milk, and aloe vera extract (50%) for 45 minutes (n=6 for each). Furthermore, positive and two negative control groups (n=6), corresponding to 0 min, 30 min, and 2-hour drying times were also prepared respectively. The number of viable cells was counted following storage using Trypan blue exclusion. Data were statistically analyzed using the one-way ANOVA and post hoc Tukey-HSD test. Results: Statistical analysis showed no significant differences in cell viability among aloe vera, soymilk, and HBSS- stored teeth; however, they were all superior to milk. Conclusion: Aloe vera extract can be recommended as a suitable storage media for avulsed teeth. PMID:28280756

  20. A revision of hominin fossil teeth from Fontana Ranuccio (Middle Pleistocene, Anagni, Frosinone, Italy).

    PubMed

    Rubini, Mauro; Cerroni, Vittorio; Festa, Giulia; Sardella, Raffaele; Zaio, Paola

    2014-12-01

    The Fontana Ranuccio hominin teeth (FR, Latium, Italy) are dated to the Middle Pleistocene. In previous studies these teeth were classified as two lower (left and right) second molars, one lower left central incisor and a badly worn incisor crown, the exact position of which could not be determined. In 2012 these remains were acquired by the Anthropological Service of S.B.A.L. (Italian Ministry of Culture) and for this reason re-analysed. In a thorough revision we have reassessed them both morphologically and dimensionally as two lower (left and right) first molars, one lower left lateral incisor and a possible upper left canine. The comparison with penecontemporaneous and diachronic samples shows that the Fontana Ranuccio teeth are morphologically similar to Atapuerca-Sima de los Huesos, Arago XIII and Neanderthal samples.

  1. Stimulation of proinflammatory cytokines by volatile sulfur compounds in endodontically treated teeth

    PubMed Central

    Lechner, Johann; von Baehr, Volker

    2015-01-01

    Persistent microorganisms in endodontically treated teeth produce volatile sulfur compounds (VSC) such as methyl mercaptan, hydrogen sulfide, and thioether. In this retrospective study, we evaluated the ex vivo immune response of peripheral blood mononuclear cells to sulfur compounds in 354 patients with systemic diseases. These systemic findings are correlated with semiquantitative values of a VSC indicator applied directly on endodontically treated teeth. Data elucidate the role of VSC in patients with immunologic diseases and the role of a semiquantitative chairside test, like the VSC indicator presented here, in correlation to IFNg and IL-10 sensitization in peripheral blood mononuclear cells. The association between ex vivo-stimulated cytokines and endodontically derived sulfur components is supported by the fact that the number of interferon gamma- and/or interleukin-10-positive sensitized patients declined significantly 3–8 months after extraction of the corresponding teeth. PMID:25792853

  2. Experimental rotordynamic coefficient results for teeth-on-rotor and teeth-on-stator labyrinth gas seals

    NASA Technical Reports Server (NTRS)

    Childs, Dara W.; Scharrer, Joseph K.

    1987-01-01

    An experimental test facility is used to measure the rotordynamic coefficients of teeth-on-rotor and teeth-on-stator labyrinth gas seals. Direct damping coefficients are presented for these seals for the first time. The results are presented for the two seal configurations at identical operating conditions, and show that, in a rotordynamic sense, the teeth-on-stator seal is more stable than the teeth-on-rotor seal, for inlet tangential velocity in the direction of rotation.

  3. Long-term forecasting of eruption hazards: A hierarchical approach to merge analogous eruptive histories

    NASA Astrophysics Data System (ADS)

    Sheldrake, Tom

    2014-10-01

    Estimating the hazard associated with a volcanic eruption requires an understanding of previous eruptive episodes to forecast future events. This involves calculating how destructive a future eruption is likely to be by estimating the magnitude of eruptive activity and likelihood of various hazardous phenomena. Importantly though, eruptive histories for individual volcanoes can suffer from a lack of observations and thus might not be representative for all future eruption scenarios. Consequently, a methodology is developed to combine eruptive histories from multiple volcanoes into an event tree framework to inform forecasts at individual volcanoes. It is based on a hierarchical Bayesian approach in which model parameters are derived for a group of volcanoes and then updated on an individual basis. However, eruptive histories are not simply aggregated and the model allows for possible heterogeneities in eruptive regimes. Continuous probability distributions are employed to capture the relative uncertainties of both global and individual records and posterior distributions for eruption magnitudes and hazardous phenomena are computed using Markov chain Monte Carlo techniques. The model is designed to initially include no subjective judgement of probabilities but is developed so that information from other analyses can be incorporated. While this article uses the hierarchical Bayesian approach specifically for event forecasting, the methodology has the potential to be used in a wide range of problems regarding hazard assessment and for the purposes of causal inference and data reduction.

  4. Eruptive History of Arenal Volcano, Costa Rica

    NASA Astrophysics Data System (ADS)

    Soto, G. J.; Alvarado, G. E.

    2004-12-01

    Tephra-stratigraphy, volcanic history, eruption types, eruptive dynamics and area distribution of tephra from the most important eruptions of Arenal volcano, are reviewed and updated. Deposits of explosive eruptions are named AR-1 to AR-22 (from older to younger). All previous and new Arenal and neighbouring Chato volcanoes' radiocarbon dates were calibrated: the last Chato eruption occurred 3720±150 B.P and the first known eruption of Arenal (AR-1), 7010+170-130 B.P. Isopachs and characteristics of the most relevant and recognized airfall deposits are presented. Area distributions of the key layers are oriented toward W, WSW and SW, except the lowest layer of AR-17, which is distributed northward. According to lithic isopleths, an eruption column height of 23 km (subplinian) was calculated for AR-20. Most fall layers in Arenal show associated pyroclastic flow deposits up to a distance of 6.5 km from the summit. They are restricted to river valley paths. Among Arenal eruptions, plinian-subplinian type events like AR-20, AR-15, AR-12 and AR-9, are the most violent and destructive, with tephra volumes between 0.2 and 1 km3. There are also violent strombolian eruptions which were sustained for a considerable time, resembling subplinian eruptions (the AR-19 case, total volume 0.45 km3), and pelean type eruptions, as AR-22, which erupted 0.026 km3 of tephra. A temporal correlation of explosive events after AR-8 shows that the four most important dacitic eruptions (AR-20, 15, 12 and 9), are separated by an average period of 800 years ("long term"). Three of them (AR-20, 15 and 9) have been preceded by two important explosive events with a more basic chemistry, which occurred around 300 years or less previously to the dacitic eruption ("short term" periods). Nevertheless, between cycles AR-13/14/15 and AR-18/19/20, there are two events (AR-16 and 17) that do not belong to any cycle. In fact, between the major eruptions AR-15 and 20, the highest eruptive frequency of all

  5. 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

  6. Modeling Eruptive Coronal Magnetohydrodynamic Systems with FLUX

    NASA Astrophysics Data System (ADS)

    Rachmeler, Laurel

    2010-05-01

    I explore solar coronal energetic eruptions in the context of magnetic reconnection, which is commonly thought to be a required trigger mechanism for solar eruptions. Reconnection is difficult to observe in the corona, and current numerical methods cannot model reconnectionless control cases. Thus, it is not possible to determine if it is a necessary component. I have executed multiple controlled simulations to determine the importance of reconnection for initiation and evolution of several eruptive systems using FLUX, a numerical model that uses the comparatively new fluxon technique. I describe two types of eruptions modeled with FLUX: a confined flux rope theory for CME initiation, and symmetrically twisted coronal jets in a uniform vertical background field. In the former, I identified an ideal MHD instability that allows metastable twisted flux rope systems to suddenly lose stability and erupt even in the absence of reconnection, contradicting previous conjecture. The CME result is in contrast to the azimuthally symmetric coronal jet initiation model, where jet-like behavior does not manifest without reconnection. I demonstrate that some eruptive phenomena may be triggered by non-reconnective means such as ideal MHD instabilities, and that magnetic reconnection is not a required element in all coronal eruptions.

  7. Weather radar observations of the Hekla 2000 eruption cloud, Iceland

    NASA Astrophysics Data System (ADS)

    Lacasse, C.; Karlsdóttir, S.; Larsen, G.; Soosalu, H.; Rose, W. I.; Ernst, G. G. J.

    The Hekla eruption cloud on 26-27 February 2000 was the first volcanic cloud to be continuously and completely monitored advecting above Iceland, using the C-band weather radar near the Keflavík international airport. Real-time radar observations of the onset, advection, and waning of the eruption cloud were studied using time series of PPI (plan-position indicator) radar images, including VMI normal, Echotop, and Cappi level 2 displays. The reflectivity of the entire volcanic cloud ranges from 0 to >60 dBz. The eruption column above the vent is essentially characterised by VMI normal and Cappi level 2 values, >30 dBz, due to the dominant influence of lapilli and ash (tephra) on the overall reflected signal. The cloud generated by the column was advected downwind to the north-northeast. It is characterised by values between 0 and 30 dBz, and the persistence of these reflections likely result from continuing water condensation and freezing on ash particles. Echotop radar images of the eruption onset document a rapid ascent of the plume head with a mean velocity of 30 to 50 m s-1, before it reached an altitude of 11-12 km. The evolution of the reflected cloud was studied from the area change in pixels of its highly reflected portions, >30 dBz, and tied to recorded volcanic tremor amplitudes. The synchronous initial variation of both radar and seismic signals documents the abrupt increase in tephra emission and magma discharge rate from 18:20 to 19:00 UTC on 26 February. From 19:00 the >45 dBz and 30-45 dBz portions of the reflected cloud decrease and disappear at about 7 and 10.5 h, respectively, after the eruption began, indicating the end of the decaying explosive phase. The advection and extent of the reflected eruption cloud were compared with eyewitness accounts of tephra fall onset and the measured mass of tephra deposited on the ground during the first 12 h. Differences in the deposit map and volcanic cloud radar map are due to the fact that the greater part

  8. Dynamics of strombolian eruptions at Batu Tara volcano (Indonesia)

    NASA Astrophysics Data System (ADS)

    Scarlato, P.; Del Bello, E.; Gaudin, D.; Taddeucci, J.; Ricci, T.; Cesaroni, C.

    2015-12-01

    In September 2014, high-speed imaging and acoustic data were acquired during 3 days of almost continuous recording (04-06/09/2015) at Batu Tara Volcano, in the small isolated island of Pulau Komba, in the Flores Sea (about 50 km N of Lembata). This volcano is very similar to the Italian Stromboli Volcano in both eruptive style and edifice morphology. The field experiment aimed at investigating degassing and explosive dynamics using a combination of GPS synchronized devices deployed in direct view of the active vent: i) a high-speed visible camera acquiring images at 500 frames per second (fps),ii) a thermal infrared (FLIR) camera acquiring at 50-200 fps, iii) a visible time lapse camera (GO-PRO) acquiring at 0.2-0.5 Hz (2 - 5 s interval), iv) two broadband microphones (Freq. range of kHz to 0.1 Hz) sampled at 10 kHz. Explosions can be discriminated in type according to their visual, thermal and acoustic features.Some explosions are characterized by a first sudden radial ejection of large spatter and bombs (main pulse), eventually followed by other similar events (secondary pulses), with very little amount of ash involved. In these eruptions, infrasonic waveforms are characterized by a first, high amplitude transient, with a first positive peak pressure followed by rapid dampening, typical of a Strombolian eruption.Other explosions are characterized by the sustained ejection of a dense jet of ash, with abundant decimeter to meter sized spatter and hot blocks.These eruptions are not accompanied by a maximum peak pressure at the eruption onset. Spectrograms show a high frequency component propagating for the entire duration of the signal.These two distinct types are sometimes overlapping and eruptions show a high amplitude transient followed by a high frequency coda. These different evolutions suggest that there are at least two repeatable explosion dynamics occurring in the conduit, with comparable gas overpressure, source depth and amount of gas involved

  9. Molecular sex identification of dry human teeth specimens from Sokoto, Northwestern Nigeria

    PubMed Central

    Zagga, AD; Ahmed, H. OON; Ismail, SM; Tadros, AA

    2014-01-01

    Background: The advent of molecular techniques has revolutionized the ability of scientists to estimate the sex of individuals. Forensic odontology plays an important role in establishing the sex of victims with bodies mutilated beyond recognition due to major disaster. The genetic difference between males and females is defined by the presence or absence of the Y-chromosome. The use of alphoid-repeat primers in sex estimation was first applied on dried blood. Generally, the X, Y alphoid repeats blind test attest to the accuracy of genetic testing, and also point the potential for occasional error in morphometric sexing. Aim: To estimate genetic sex of dry human teeth specimens from Sokoto, Northwestern Nigeria, using polymerase chain reaction (PCR). Materials and Methods: A single-blind study of DNA analysis for sex estimation of nine dry human teeth specimens from Sokoto, Northwestern Nigeria, through PCR, using alphoid repeats primers, was undertaken. Results: The genetic sex of each group of the teeth samples were accurately (100%) identified. For each group of teeth, PCR Sensitivity = 100%, Specificity = 0%, Predictive value of positive test = 100%, Predictive value of negative test = 0%, False positive rate = 0%, False negative rate = 0%, Efficiency of test = 100%. Fisher's exact probability test P = 1. Z-test: z- and P values were invalid. Conclusion: This study has demonstrated the successful use of alphoid-repeat primers in genetic sex identification of human dry teeth samples from Sokoto, Northwestern Nigeria. This is the first known study estimating the sex of human dry teeth specimens by means of PCR in Nigeria. There is need for further studies in Nigeria to complement the findings of this study. PMID:25125922

  10. Coronal microleakage of endodontically treated teeth with intracanal post exposed to fresh human saliva

    PubMed Central

    de OLIVEIRA, Simone Gomes dias; GOMES, Denise Jornada; COSTA, Marcelo Hissé das Neves; de SOUSA, Ezilmara Rolim; LUND, Rafael Guerra

    2013-01-01

    Objective The aim of this study was to investigate the coronal microleakage of endodontically treated teeth prepared to receive an intracanal post and teeth with an intracanal post but without a prosthetic crown and exposed to contamination by fresh human saliva. Material and Methods A mechanical-chemical preparation following the step-back technique was carried out in 35 extracted single-rooted human teeth. The teeth were randomly divided into five groups: G1=root canals instrumented, obturated, and prepared to receive an intracanal post (N=10); G2=root canals with cemented posts but without coronal sealing (N=10); PC1=positive control root canals instrumented and open (N=5); PC2=positive control 2 root canals without instrumentation and open (N=5); and NC=negative control healthy teeth (N=5). The crowns were removed except for the control group of intact teeth. The root canals were obturated and sterilized with cobalt 60 gamma irradiation and were then adapted in an apparatus using a Brain Heart Infusion (BHI) medium and fresh human saliva for contamination. Microbial growth was indicated by the presence of turbidity in the BHI liquid medium. Results Data were submitted to the Kaplan-Meier Survival Analysis and the Holm-Sidak statistic method, which observed an index of 90% of microleakage in root canals after 24 hours for G1 and 70% of microleakage in samples at the end of 40 days for G2. Conclusion The results show that root canals with an intracanal post but without a prosthetic crown can be recontaminated when exposed to fresh human saliva in a short period. PMID:24212985

  11. Pulp revascularization of immature dog teeth with apical periodontitis.

    PubMed

    Thibodeau, Blayne; Teixeira, Fabricio; Yamauchi, Mitsuo; Caplan, Daniel J; Trope, Martin

    2007-06-01

    This study examined the ability of a collagen solution to aid revascularization of necrotic-infected root canals in immature dog teeth. Sixty immature teeth from 6 dogs were infected, disinfected, and randomized into experimental groups: 1: no further treatment; 2: blood in canal; 3: collagen solution in canal, 4: collagen solution + blood, and 5: negative controls (left for natural development). Uncorrected chi-square analysis of radiographic results showed no statistical differences (p >or= 0.05) between experimental groups regarding healing of radiolucencies but a borderline statistical difference (p = 0.058) for group 1 versus group 4 for radicular thickening. Group 2 showed significantly more apical closure than group 1 (p = 0.03) and a borderline statistical difference (p = 0.051) for group 3 versus group 1. Uncorrected chi-square analysis revealed that there were no statistical differences between experimental groups for histological results. However, some roots in each of groups 1 to 4 (previously infected) showed positive histologic outcomes (thickened walls in 43.9%, apical closure in 54.9%, and new luminal tissue in 29.3%). Revascularization of disinfected immature dog root canal systems is possible.

  12. Intracoronal bleaching of discolored non-vital teeth.

    PubMed

    Bizhang, Mozhgan; Heiden, Anke; Blunck, Uwe; Zimmer, Stefan; Seemann, Rainer; Roulet, Jean-François

    2003-01-01

    This clinical study compared the effectiveness of bleaching non-vital teeth with an open pulp chamber during bleaching using 10% carbamide peroxide compared to the modified walking bleach technique and extracoronal bleaching. Sixty discolored, non-vital teeth were treated. They were divided into three groups. Each group was treated with one of the bleaching materials and methods: extracoronally using 10% carbamide peroxide for two weeks as negative control (Group A), intracoronally using sodium perborate mixed with 3% hydrogen peroxide (modified walking bleach technique) (Rotstein, Mor & Friedman, 1993) for four weeks (Group B) and intracoronally and extracoronally using 10% carbamide peroxide for two weeks (Group C) (Liebenberg, 1997). Tooth color was measured at baseline, (BL), immediately post-bleaching (IP) and six months post-bleaching (SP) with a colorimeter (Castor, Sigma, Germany) using a tooth-positioning jig. The color was determined according to the CIELAB system, which records lightness as L* and chromaticity coordinates as a* and b*. The difference in L* and b* among the three groups was significant between BL and IP examination. The post-bleaching, whitening effect in Group C was significantly better, but after six months, in Group C, it was as effective as in Group B.

  13. 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

  14. Letter: Lichenoid eruption induced by etanercept.

    PubMed

    Barrientos, Nuria; García-Sánchez, Sagrario; Domínguez, José D

    2012-07-15

    Lichenoid drug eruption is an uncommon, but previously reported, side effect of anti-tumor necrosis factor therapy. The majority of these adverse events relate to infliximab. We report a patient who developed a lichenoid eruption on the back of her hands during etanercept therapy. She improved with topical treatment and discontinuation of the drug was not necessary. The physiopathological link between anti-TNF treatment and lichenoid eruptions remains unclear. It is important to realize that a lichenoid reaction pattern may occur during anti-TNF agent treatment.

  15. A model for Plinian eruptions of Vesuvius

    NASA Astrophysics Data System (ADS)

    Sheridan, M. F.; Barberi, F.; Rosi, M.; Santacroce, R.

    1981-01-01

    The term `Plinian' has been widely used1-4 to describe continuous gas-blast eruptions of large magnitude a typical example5, of which is the AD 79 eruption of Vesuvius which destroyed Pompei and the surrounding region. We develop a new model here for the AD 79 event that explains the complete Plinian eruptive episode including pyroclastic fall, pyroclastic flow, base surge, laharic and phreatic activity. This model has widespread implications with regard to volcanic hazard evaluation and geothermal exploration at Vesuvius and other volcanoes with similar patterns of activity, such as Mount St Helens.

  16. Timing signatures of large scale solar eruptions

    NASA Astrophysics Data System (ADS)

    Balasubramaniam, K. S.; Hock-Mysliwiec, Rachel; Henry, Timothy; Kirk, Michael S.

    2016-05-01

    We examine the timing signatures of large solar eruptions resulting in flares, CMEs and Solar Energetic Particle events. We probe solar active regions from the chromosphere through the corona, using data from space and ground-based observations, including ISOON, SDO, GONG, and GOES. Our studies include a number of flares and CMEs of mostly the M- and X-strengths as categorized by GOES. We find that the chromospheric signatures of these large eruptions occur 5-30 minutes in advance of coronal high temperature signatures. These timing measurements are then used as inputs to models and reconstruct the eruptive nature of these systems, and explore their utility in forecasts.

  17. Analysis of a Limb Eruptive Event

    NASA Astrophysics Data System (ADS)

    Kotrč, P. Kupryakov, Yu. A.; Bárta, M.; Kashapova, K., L.; Liu, W.

    2016-04-01

    We present the analysis of an eruptive event that took place on the eastern limb on April 21, 2015, which was observed by the Ondřejov horizontal telescope and spectrograph. The eruption of the highly twisted prominence was followed by the onset of soft X-ray sources. We identified the structures observed in Hα spectra with the details on the Hα filtergrams and analyzed the evolution of Doppler component velocities. The timing and observed characteristics of the eruption were compared with the prediction of the model based on the twisting of the flux ropes and the kink/torus instability.

  18. Magmatic volatiles in explosive rhyolitic eruptions

    SciTech Connect

    Eichelberger, J.C.; Westrich, H.R.

    1981-07-01

    Obsidian clasts in rhyolitic tephra deposits preserve preeruption magmatic volatile contents, providing a direct means for determining the volatile content of explosively erupted magmas. Small to moderate volume Plinian eruptions (10/sup -3/ to 10/sup -1/ km/sup 3/) appear to be driven by 0.5--1.0 wt.% volatiles, consisting dominantly of H/sub 2/O with minor CO/sub 2/. Analysis of obsidian from eruptive sequences consisting of tephra and flows indicates that this hydrous magma abruptly overlies magma with only 0.1--0.2 wt.% H/sub 2/O.

  19. 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

  20. An unusual case of black teeth.

    PubMed

    Schuurs, A H; Abraham-Inpijn, L; van Straalen, J P; Sastrowijoto, S H

    1987-10-01

    Loss of enamel and a deep black stain of the teeth in a 40-year-old diabetic patient are strongly suggested to be caused by the daily consumption of a cheap white wine and, possibly, by the chewing of cayenne. The wine proved to be rather acid, thereby promoting abrasion as a result of gnashing, and to contain a high concentration of tannin. The exact role of the tannins is described.

  1. Bleaching non vital primary teeth: case report.

    PubMed

    Bussadori, Sandra Kalil; Roth, Faynna; Guedes, Carolina Cardoso; Fernandes, Kristiane Porta; Domingues, Manoela Martins; Wanderley, Márcia Turolla

    2006-01-01

    Trauma and pulpal infections in primary dentition are part of the routine of the pediatric dentist. Common consequences in these cases are alterations in dental color, compromising patient's esthetics and his interaction in social environment. Bleaching intends to preserve dental structure already weakened and to show immediate esthetic results. This clinical case shows a bleaching technique in devitalized primary teeth using bleaching agent with 35% hydrogen peroxide activated by photo polymerizer. This technique is simple and shows immediate satisfactory results.

  2. Two types of volcanic tremor changed with eruption style during 1986 Izu-Oshima eruption

    NASA Astrophysics Data System (ADS)

    Kurokawa, Aika; Takeo, Minoru; Kurita, Kei

    2016-04-01

    Volcanic tremor provides clues to magma migration pathways so that tremor source location is expected to be an efficient tool for tracking dynamic behavior of magma in evolution of eruptive activity. However, clear evidence, which connects between temporal variation in volcanic tremor and evolution of eruption style, is still lacking. We have analyzed volcanic tremors occurred during 1986 Izu-Oshima eruption using recently digitized data. The results present a clear link between eruption styles, waveform variations and source locations of the tremors. Moreover, precursory activity of the tremors that indicates injection of magma below fissures has been clarified 5 days prior to the fissure eruptions. This demonstrates predominance of tremor activity as an adaptive monitoring tool in volcanic eruption.

  3. A Toba-scale eruption in the Early Miocene: The Semilir eruption, East Java, Indonesia

    NASA Astrophysics Data System (ADS)

    Smyth, Helen R.; Crowley, Quentin G.; Hall, Robert; Kinny, Peter D.; Hamilton, P. Joseph; Schmidt, Daniela N.

    2011-10-01

    The Indonesian archipelago is well-known for volcanic activity and has been the location of three catastrophic eruptions in the last million years: Krakatau, Tambora and Toba. However, there are no reports of large magnitude eruptions during the earlier Cenozoic despite a long volcanic record in Indonesia during subduction of Indian Ocean lithosphere since the Eocene. Here we report an Early Miocene major eruption, the Semilir eruption, in south Java, the main phase of which occurred at 20.7 ± 0.02 Ma. This major volcanic eruption appears similar in scale, but not in type, to the 74 ka Toba event. Its products can be identified elsewhere in Java and are likely to have been distributed widely in SE Asia and adjacent oceans. The Semilir eruption could have triggered a climate response, but cannot yet be linked with certainty to Early Miocene climatic events such as glaciations.

  4. A Changing Trend In Eruption Age and Pattern of First Deciduous Tooth: Correlation to Feeding Pattern

    PubMed Central

    Kohli, Monika V; Patil, Gururaj B.; Kulkarni, Narayan B.; Bagalkot, Kishore; Purohit, Zarana; Dave, Nilixa; Sagari, Shitalkumar G; Malaghan, Manjunath

    2014-01-01

    Background: Feeding mode during infancy and its effect on deciduous tooth appearance in oral cavity in two generations and among genders. Aim and Objective: Study aimed to compare and correlate times and patterns of deciduous tooth eruption in breastfeeding (OBF), partial breastfeeding (PBF) and spoon feeding (SF) infants and initiation of semisolid food feeding (SSF) in infants. It also aimed to address the variations in the time of eruption of first deciduous tooth and its pattern in two generations who had more than a decade of difference in ages. Materials and methods: An open-ended questionnaire study was conducted on mothers of 265 patients from two groups, generation 1 (G1)- adults who were aged 20-35 years and second group, generation 2 (G2) - children who were below 5 years of age . Results: A statistical significance was observed with respect to age, gender, generations, and frequency of breastfeeding, partial breastfeeding and time of initiation of semisolid food. Conclusion: There is a delayed eruption of teeth in present generation. For girls, it occurs at age of 7.88 months and for boys, it occurs at the age of 8.08 months. PMID:24783136

  5. Methods for monitoring and forecasting volcanic hazards and eruptions using seismology and other geophysical data

    NASA Astrophysics Data System (ADS)

    DeRoin, Nicole

    Recent eruptions of three Alaskan volcanoes have provided the opportunity to study the relationships between seismicity and volcanic hazards and other phenomena. The ability to forecast or track volcanic activity through seismicity is important because seismic monitoring can be done in real time, 24 hours a day, regardless of weather, dangerous conditions or distance. To this end, the eruptions of Veniaminof in 2005, Augustine Volcano in 2006, and Redoubt Volcano in 2009, have been studied with the focus on understanding how seismic recordings and measurements are related to physical characteristics of eruption phenomena. Positive correlations were seen in relationships between ash plume heights at Veniaminof and their accompanying seismic magnitudes, and sizes and directions of rockfalls and block-and-ash flows at Augustine with seismic amplitude ratios and magnitudes. The relationship of rockfall occurrences in background years was also correlated with seasons and weather patterns, making easier the identification of rockfall increases that may be eruption precursors. Volcanic tremor, which frequently occurs accompanying volcanic eruptions, is studied during the Redoubt eruption, through the generation of duration-amplitude plots, and the potential for a new forecasting or monitoring tool is discussed.

  6. Revisiting the observed surface climate response to large volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Wunderlich, Fabian; Mitchell, Daniel M.

    2017-01-01

    In light of the range in presently available observational, reanalysis and model data, we revisit the surface climate response to large tropical volcanic eruptions from the end of the 19th century until present. We focus on the dynamically driven response of the North Atlantic Oscillation (NAO) and the radiative-driven tropical temperature response. Using 10 different reanalysis products and the Hadley Centre Sea Level Pressure observational dataset (HadSLP2) we confirm a positive tendency in the phase of the NAO during boreal winters following large volcanic eruptions, although we conclude that it is not as clear cut as the current literature suggests. While different reanalyses agree well on the sign of the surface volcanic NAO response for individual volcanoes, the spread in the response is often large (˜ 1/2 standard deviation). This inter-reanalysis spread is actually larger for the more recent volcanic eruptions, and in one case does not encompass observations (El Chichón). These are all in the satellite era and therefore assimilate more atmospheric data that may lead to a more complex interaction for the surface response. The phase of the NAO leads to a dynamically driven warm anomaly over northern Europe in winter, which is present in all datasets considered. The general cooling of the surface temperature due to reduced incoming shortwave radiation is therefore disturbed by dynamical impacts. In the tropics, where less dynamically driven influences are present, we confirm a predominant cooling after most but not all eruptions. All datasets agree well on the strength of the tropical response, with the observed and reanalysis response being statistically significant but the modelled response not being significant due to the high variability across models.

  7. Infrared Imaging of Strombolian Eruptions

    NASA Astrophysics Data System (ADS)

    Dehn, J.; Harris, A. J.; Ripepe, M.

    2001-12-01

    A forward looking infrared radiometer (FLIR) was used experimentally to capture time series imagery of strombolian eruptions during May and June of 2001 at Stromboli and Etna volcanoes. Though an image is captured only every second or two, eruption sequences covering over 13 hours of imagery over 2 weeks were acquired. Four distinct types of bursts were captured. The first 3 types were observed at Stromboli, and a fourth unique signature was observed at SE crater on Mount Etna. At Stromboli, the three types are; 1) Spatter followed by gas emissions, 2) Gas emissions followed by spatter bursts, and 3) Simultaneous ejections of gas and spatter. Each shows a unique morphology in the time series imagery. The spatter bursts have varying amounts of gas which follow, the gas being much cooler (on the order of 100 degrees Cor more) than the spatter. The volumes of gas estimated using the 2D imagery vary widely, as yet no pattern to this behavior has been discovered. The spatter is not always a single burst, several small sustained (on the order of several seconds) spatter events were observed. The primarily gas bursts showed higher gas volumes and higher gas temperatures than the primarily spatter ejections. Spatter usually, but not always, follows these emissions, and is less voluminous than in the previous ejection type. In the third type, both spatter and gas are ejected simultaneously, the gas emission usually lasting longer than the spatter event. Determination of relative temperatures of the two components is problematic since they overlay one another in the imagery. No relative temperature determinations are made as yet to ejection temperature of spatter in these types due to the relatively small size of the lava bombs in relation to the pixel size in the imagery. However, temperatures over 700 degrees C have been recovered. At Etna a fourth type of burst, mostly gas with a mushroom-shaped structure, followed by a few high ejection angle bombs was observed. These

  8. 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

  9. Radiodensity and hardness of enamel and dentin of human and bovine teeth, varying bovine teeth age.

    PubMed

    Fonseca, R B; Haiter-Neto, F; Carlo, H L; Soares, C J; Sinhoreti, M A C; Puppin-Rontani, R M; Correr-Sobrinho, L

    2008-11-01

    Studies have evaluated dental hard tissues characteristics from animal species in order to be used as a substitute for human teeth. The aim of this study was to evaluate the radiodensity and hardness of human and bovine enamel and dentin, varying bovine teeth age. Five specimens (1mm thick) were obtained from animals aged 20 (B20), 30 (B30), 38 (B38) and 48 (B48)months and from 20 to 30-years-old human third molars (H). The radiographic images were taken with a phosphor plaque digital system (Digora Optime). The radiodensity was obtained and Knoop hardness (KHN) was recorded (100g for 15s--5 indentations per specimen). Data were analyzed by one-way ANOVA following Tukey's HSD test and Dunnet's two-sided t-test. Radiodensity was similar within enamel groups, but bovine dentin presented higher radiodensity than human one regardless of age groups. Enamel-KHN showed differences between B20-B30 and B38-B48-H, and dentin-KHN was similar within all groups. Enamel was always more radiodense than dentin and also presented higher KHN (p=0.001). The use of bovine enamel or dentin should take into consideration the teeth age, but as a general rule it should be recommended to select older bovine teeth due to better chances to find greater similarity with human teeth.

  10. Volcanic Eruptions and Climate: Sulfates are More Important Than Halogens in Producing Climate Change

    NASA Astrophysics Data System (ADS)

    Robock, A.

    2007-12-01

    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 this aerosol cloud produce responses in the climate system. Using examples from major eruptions of the past and results from experiments with numerical models of the climate system, this talk illustrates the major impacts. Volcanic eruptions produce global cooling, and are an important natural cause of interdecadal and interannual 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. High latitude eruptions in the Northern Hemisphere, while also producing global cooling, do not have the same impact on atmospheric dynamics. They weaken the Indian and African summer monsoon, and the effects can be seen in past records of flow in the Nile and Niger Rivers. In fact we can use records of the Nile River flow to provide an improved date for the Eldgjá eruption in Iceland, which we now date at 939 A.D. While halogens may have short term effects on ozone in plumes with high halogen concentrations, there is no evidence that they are important in the global climate response to volcanic eruptions.

  11. Prevalence of sequelae in the permanent anterior teeth after trauma in their predecessors: a longitudinal study of 8 years.

    PubMed

    do Espírito Santo Jácomo, Diana Ribeiro; Campos, Vera

    2009-06-01

    The aim of this study was to determine the prevalence of sequelae in the permanent anterior teeth following trauma in their predecessors, and also to verify the existence of association between the sequelae in the permanent teeth and the type of injury in their predecessors according to the age group at the time of injury. This study was performed based on data from the records of 169 boys and 138 girls who received assistance at the dental clinic of the State University of Rio de Janeiro from March 1996 to December 2004. The sample was collected from 753 traumatized deciduous teeth of children aged 0-10 years. The number of boys and girls with dental trauma corresponded to 55.0% and 45.0%, respectively. The more affected age period was between 1 and 4 years (75.3%). The most common type of traumatic injury was the intrusion (29.3%), followed by avulsion (14.1%). Concerning permanent dentition, the most common developmental disturbances were discoloration of enamel and/or enamel hypoplasia (46.08%) and eruption disturbances (17.97%) due to the traumatic injury in their predecessors. It was not possible to find an association between the type of injury in primary teeth and sequelae in their successors in the studied age groups (P teeth and the type of traumatic injury in their predecessors in the studied age groups.

  12. C3-class Solar Flare Eruption

    NASA Video Gallery

    Just as sunspot 1105 was turning away from Earth on Sept. 8, the active region erupted, producing a C3-class solar flare (peak @ 2330 UT) and a fantastic prominence. This is a three color closeup o...

  13. 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. 

  14. Ring-shaped Prominence Erupts from Sun

    NASA Video Gallery

    A coronal mass ejection (CME) on Jan. 31, 2013 was accompanied by a large prominence eruption best visible in light with a wavelength of 304 angstroms. NASA’s Solar Dynamics Observatory captured ...

  15. Lower third molar eruption following orthodontic treatment.

    PubMed

    Salehi, P; Danaie, S Momene

    2008-01-01

    This study assessed the effect of extraction and preservation of the 1st premolar on lower 3rd molar eruption. Orthodontic clinic records from 1993 to 1995 were evaluated before and after treatment and 8-9 years after treatment for 3 groups of patients: 32 with extraction of 1st premolars in both jaws, 32 with no extraction but orthodontic treatment and 48 controls with no extraction but orthodontic treatment in the upper jaws only. Successful eruption of 3rd molars was evaluated. There was a significant difference in the rates of successful eruptions in the extraction (42%), non-extraction (12%) and control (20%) groups. The findings indicate that 1st premolar extraction may increase the chance of 3rd molar eruption, leading to a lower incidence of health and economic complications.

  16. Depth of origin of magma in eruptions

    PubMed Central

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

    2013-01-01

    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. PMID:24067336

  17. 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.

  18. Winter warming from large volcanic eruptions

    SciTech Connect

    Robock, A.; Jianping Mao )

    1992-12-24

    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% 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. 21 refs., 2 figs., 1 tab.

  19. Differential Diagnosis of Linear Eruptions in Children.

    PubMed

    Kruse, Lacey L

    2015-08-01

    A 3-year-old girl presented with a linear eruption on her leg for 2 months. She was otherwise healthy and well-appearing. Physical examination showed many small, erythematous, flat-topped papules coalescing into a linear erythematous plaque. At a follow-up visit 9 months later, the eruption had resolved, leaving postinflammatory hypopigmentation.When approaching a cutaneous eruption, appreciating the pattern of the lesions can be instrumental to arriving at the correct diagnosis. For this patient with the acute onset of a plaque on the leg, the differential diagnosis is narrowed by the linear distribution of the skin lesions. The differential diagnosis of linear eruptions in children includes lichen striatus, linear lichen planus, linear psoriasis, inflammatory linear verrucous epidermal nevus, incontinentia pigmenti, phytophotodermatitis, and allergic contact dermatitis. Of note, many of these conditions manifest in a linear manner as a result of cutaneous mosaicism, whereas others are caused by external agents contacting the skin.

  20. STEREO's View of Aug. 24, 2014 Eruption

    NASA Video Gallery

    A bright eruption of solar material surges into space as captured by NASA's Solar Terrestrial Relations Observatory - Before satellite, which currently has a view of the far side of the sun. The in...

  1. 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

  2. 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.

  3. Italian super-eruption larger than thought

    NASA Astrophysics Data System (ADS)

    Schultz, Colin

    2012-07-01

    Recent research suggested that the super-eruption of the Campi Flegrei caldera volcano in southern Italy about 40,000 years ago may have played a part in wiping out, or forcing the migration of, the Neanderthal and modern human populations in the eastern Mediterranean regions that were covered in ash. Now a new modeling study by Costa et al. suggests that this eruption may have been even larger than previously thought. This Campi Flegrei eruption produced a widespread ash layer known as Campanian Ignimbrite (CI). Using ash thickness measurements collected at 115 sites and a three-dimensional ash dispersal model, the researchers found that the CI super-eruption would have spread 250-300 cubic kilometers of ash across a 3.7-million-square kilometer region—2 to 3 times previous ash volume estimates.

  4. 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

  5. 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.

  6. 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.

  7. 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

  8. 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

  9. 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

  10. Tephra from the 1979 soufriere explosive eruption.

    PubMed

    Sigurdsson, H

    1982-06-04

    The explosive phase of the 1979 Soufriere eruption produced 37.5 x 10(6) cubic meters (dense-rock equivalent) of tephra, consisting of about 40 percent juvenile basaltic andesite and 60 percent of a nonjuvenile component derived from the fragmentation of the 1971-1972 lava island during phreatomagmatic explosions. The unusually fine grain size, poor sorting, and bimodality of the land deposit are attributed to particle aggregation and the formation of accretionary lapilli in a wet eruption column.

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

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Mt. Pinatubo on the island of Luzon (14.5N, 120.5E) erupted catastrophically in June 1991 after over 600 years of inactivity. Partially obscured by clouds in this post eruption photo, the crater is not obvious in this scene but the blowout area, in the once heavily forested region, is easily observed as lava flow, ash fallout, mud slide and debris trails mar the landscape. Clark AFB, once the crossroads of the SW Pacific can only partially be seen.

  12. Are flood basalt eruptions monogenetic or polygenetic?

    NASA Astrophysics Data System (ADS)

    Sheth, Hetu C.; Cañón-Tapia, Edgardo

    2015-11-01

    A fundamental classification of volcanoes divides them into "monogenetic" and "polygenetic." We discuss whether flood basalt fields, the largest volcanic provinces, are monogenetic or polygenetic. A polygenetic volcano, whether a shield volcano or a stratovolcano, erupts from the same dominant conduit for millions of years (excepting volumetrically small flank eruptions). A flood basalt province, built from different eruptive fissures dispersed over wide areas, can be considered a polygenetic volcano without any dominant vent. However, in the same characteristic, a flood basalt province resembles a monogenetic volcanic field, with only the difference that individual eruptions in the latter are much smaller. This leads to the question how a flood basalt province can be two very different phenomena at the same time. Individual flood basalt eruptions have previously been considered monogenetic, contrasted by only their high magma output (and lava fluidity) with typical "small-volume monogenetic" volcanoes. Field data from Hawaiian shield volcanoes, Iceland, and the Deccan Traps show that whereas many feeder dykes were single magma injections, and the eruptions can be considered "large monogenetic" eruptions, multiple dykes are equally abundant. They indicate that the same dyke fissure repeatedly transported separate magma batches, feeding an eruption which was thus polygenetic by even the restricted definition (the same magma conduit). This recognition helps in understanding the volcanological, stratigraphic, and geochemical complexity of flood basalts. The need for clear concepts and terminology is, however, strong. We give reasons for replacing "monogenetic volcanic fields" with "diffuse volcanic fields" and for dropping the term "polygenetic" and describing such volcanoes simply and specifically as "shield volcanoes," "stratovolcanoes," and "flood basalt fields."

  13. Azithromycin induced bullous fixed drug eruption.

    PubMed

    Das, Anupam; Sancheti, Karan; Podder, Indrashis; Das, Nilay Kanti

    2016-01-01

    Fixed drug eruption (FDE) is a common type of drug eruption seen in skin clinics. It is characterized by solitary or multiple, round to oval erythematous patches with dusky red centers, some of which may progress to bulla formation. Bullous FDE may be caused by a number of drugs. We hereby describe a case of azithromycin-induced bullous FDE; to the best of our knowledge, this is the first such case being reported.

  14. Generalized pustular eruptions due to terbinafine.

    PubMed

    Ozturk, Gunseli; Turk, Bengu Gerceker; Karaca, Nezih; Karaarslan, Isil Kilinc; Ertekin, Banu; Ertam, Ilgen; Kazandi, Alican; Kandiloglu, Gulsen

    2012-03-01

    Terbinafine, a widely used antifungal agent, may rarely cause cutaneous side effects with an incidence of 2.7%. Generalized pustular eruptions are quite uncommon but severe adverse cutaneous reactions of terbinafine have been reported. The main pustular eruptions due to terbinafine include acute generalized exanthematous pustulosis and drug induced pustular psoriasis. In this report, two cases of acute generalized exanthematous pustulosis and one case of generalized pustular psoriasis triggered with terbinafine are presented.

  15. A Nanolite Record of Eruption Style Transition

    NASA Astrophysics Data System (ADS)

    Mujin, M.; Nakamura, M.

    2014-12-01

    Microlites in pyroclasts have been intensively studied to understand magma ascent processes. However, microlites do not record the explosive-effusive transitions in sub-Plinian eruptions when such transitions are governed by the shallow level degassing rather than by the magma ascent rate. To overcome this limitation, we studied the "nanolites" in the quenched products of the 2011 Shinmoedake, Kirishima Volcanic Group, Kyusyu Japan1. Nanolites are the nanometer-scale components of the groundmass minerals and exhibit a steeper slope of crystal size distribution than that of the microlites2. In the 2011 Shinmoedake eruption, the style of activity had undergone transformations from sub-Plinian eruption to Vulcanian explosion and intermittent effusion of lava3. We found that, although the products formed by different eruptive activities have similar microlite characteristics, such products can be distinguished clearly by their mineral assemblage of nanolites. The samples of pumices of sub-Plinian eruptions and Vulcanian explosions and the dense juvenile fragments of lava (in descending order of explosivity) contained, respectively, nanolites of low-Ca pyroxene, low-Ca pyroxene + plagioclase, and low-Ca pyroxene + plagioclase + Fe-Ti oxides. Nanolites are assumed to crystallize when undercooling of the magma due primarily to dehydration increases rapidly near the surface. The water contents of the interstitial glass indicate that the quenched depths did not differ greatly between eruption styles. Hence, the different nanolite assemblages of each eruption style are assumed to have resulted from differences in magma residence time near the surface. Thus, we propose that nanolites in pyroclasts have the potential to indicate the physicochemical conditions of magma at the transition points of eruption styles. References 1) Mujin and Nakamura, 2014, Geology, v.42, p.611-614 2) Sharp et al., 1996, Bull. Volcanol, v.57, p.631-640 3) Miyabuchi et al, 2013, J. Volcanol

  16. Extracellular Matrix-mediated Tissue Remodeling Following Axial Movement of Teeth

    PubMed Central

    Luan, Xianghong; Ito, Yoshihiro; Holliday, Sean; Walker, Cameron; Daniel, Jon; Galang, Therese M.; Fukui, Tadayoshi; Yamane, Akira; Begole, Ellen; Evans, Carla; Diekwisch, Thomas G.H.

    2007-01-01

    SUMMARY Tooth eruption is a multifactorial process involving movement of existing tissues and formation of new tissues coordinated by a complex set of genetic events. We have used the model of the unopposed rodent molar to study morphological and genetic mechanisms involved in axial movement of teeth. Following extraction of opposing upper molars, lower molars supererupted by 0.13 mm. Labeled tissue sections revealed significant amounts of new bone and cementum apposition at the root apex of the unopposed side following supereruption for 12 days. Newly apposited cementum and alveolar bone layers were approximately 3-fold thicker in the experimental vs the control group, whereas periodontal ligament width was maintained. Tartrate-resistant acid phosphatase staining indicated bone resorption at the mesial alveolar walls of unopposed molars and provided in tandem with new bone formation at the distal alveolar walls an explanation for the distal drift of molars in this model. Microarray analysis and semiquantitative RT-PCR demonstrated a significant increase in collagen I, integrin β5, and SPARC gene expression as revealed by comparison between the unopposed molar group and the control group. Immunohistochemical verification revealed increased levels of integrin β5 and SPARC labeling in the periodontal ligament of the unopposed molar. Together our findings suggest that posteruptive axial movement of teeth was accomplished by significant formation of new root cementum and alveolar bone at the root apex in tandem with upregulation of collagen I, integrin β5, and SPARC gene expression. PMID:17015623

  17. 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. 

  18. The 808 nm Laser-Assisted Surgery as an Adjunct to Orthodontic Treatment of Delayed Tooth Eruption

    PubMed Central

    Seifi, Massoud; Vahid-Dastjerdi, Elahe; Ameli, Nazila; Badiee, Mohammad-Reza; Younessian, Farnaz; Amdjadi, Parisa

    2013-01-01

    Introduction: Failure of teeth to erupt from gingival tissues at usual developmental time is called delayed tooth eruption (DTE). Delayed tooth eruption lead to prolonged fixed orthodontic treatment and its eventual complications. The purpose of the present study was to evaluate the effect of laser-assisted (808 nm) surgical uncovering, on the tooth emergence and orthodontic treatment of DTE. Methods: A total of 16 orthodontic patients were included in this study and were equally assigned to an experimental and a control group. Subjects for experiment consisted of eight patients (6 girls and 2 boys) with a mean age of 14±0.9 years. All patients exhibited delayed second premolar eruption. The laser wavelength was 810 nm and it was set in a continuous wave mode at a power output of 1.6 watt with a 0.3-mm diameter fiber tip. When the target tissue was sufficiently anesthetized, the tip was directed at an angle of 10 to 20 degrees to the tissue (light contact mode); and was applied continuously for approximately 12 Seconds until an acceptable tooth exposure area was visible. The facial axis of the clinical crown (FACC) line represents the most prominent portion of the facial central lobe for premolars. All orthodontic brackets are aligned along this reference and are located on FA (Facial Axis) point. The standard for adequate tooth eruption was the accessibility of facial axis of the clinical crown (FACC) for bonding the brackets. Data gathered from the patients were statistically surveyed and compared by means of Tukey’s Test and Analysis of Variance (ANOVA). Results: All patients showed good gingival status, no significant bleeding during or immediately after the surgery, and acceptable level of healing after laser surgery. The biologic width of the teeth was preserved and no violation of this important periodontal parameter was observed. The average time for accessing the FA point in experimental group was 11±1.1 weeks and the mentioned period was increased to

  19. Identifying recycled ash in basaltic eruptions

    NASA Astrophysics Data System (ADS)

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

    2014-07-01

    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.

  20. Excitation of atmospheric oscillations by volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Kanamori, Hiroo; Mori, Jim; Harkrider, David G.

    1994-11-01

    We investigated the mechanism of atmospheric oscillations with periods of about 300 s which were observed for the 1991 Pinatubo and the 1982 El Chichon eruptions. Two distinct spectral peaks, at T = 270 and 230 s for the Pinatubo eruption and at T = 195 and 266 s for the El Chichon eruptions, have been reported. We found similar oscillations for the 1980 Mount St. Helens and the 1883 Krakatoa eruptions. To explain these observations, we investigated excitation problems for two types of idealized sources, 'mass injection' and 'energy injection' sources, placed in an isothermal atmosphere. In general, two modes of oscillations, 'acoustic' and 'gravity' modes, can be excited. For realistic atmospheric parameters, the acoustic and gravity modes have a period of 275 and 304 s, respectively. For a realistic time history of eruption, atmospheric oscillations with an amplitude of 50 to 100 Pa (0.5 to 1 mbar) can be excited by an energy injection source with a total energy of 10(exp 17) J. This result is consistent with the observations and provides a physical basis for interpretation of atmospheric oscillations excited by volcanic eruptions.

  1. Effects of Vent Asymmetry on Explosive Eruptions

    NASA Astrophysics Data System (ADS)

    Sim, S.; Ogden, D. E.

    2012-12-01

    Current computer models of volcanic eruptions are typically based on symmetric vent and conduit geometries. However, in natural settings, these features are rarely perfectly symmetric. For example, the May 18, 1980 eruption of Mount St Helens (MSH) took place through a highly asymmetrical crater due to the preceding landslide and subsequent vent erosion. In supersonic, high pressure eruptions, such as what may have occurred at MSH, vent and crater asymmetry can strongly affect the directionality of the gas-thrust region. These effects on eruption direction may have implications for the formation of lateral blasts and pyroclastic density currents (PDCs). Here, we present preliminary results from numerical simulations using CartaBlanca, a Java based simulation tool for non-linear physics as developed at Los Alamos National Laboratory. Using 2D time-dependent simulations of explosive volcanic eruptions, we study the effects of vent asymmetry on a variety of eruptive conditions. Preliminary results suggest that asymmetric vent shape may provide an additional mechanism for the formation of lateral blasts and PDCs.

  2. Mafic Plinian eruptions: Is fast ascent required?

    NASA Astrophysics Data System (ADS)

    Szramek, Lindsay Ann

    2016-10-01

    It has been hypothesized that for a Plinian eruption of mafic magma to occur, that magma must ascend rapidly from the chamber to cause it to fragment into a jet containing juvenile and nonjuvenile tephra. To determine how fast mafic Plinian magmas need to travel to the level of fragmentation, a number of decompression experiments were carried out on two hydrous mafic magmas, and the results are compared to the products of two well-documented mafic Plinian eruptions: the basaltic andesite Fontana eruption of Masaya (Nicaragua) and the hawaiite 122 B.C. eruption of Etna (Italy). Comparison of natural and experimental textures shows that the Fontana eruption can be replicated in the lab at decompression rates between 0.1 MPa s-1 and 0.2 MPa s-1. This decompression rate is faster than any previously determined experimentally rate for more silicic eruptions. The hawaiite was unable to be reproduced in the lab. The natural groundmass is highly crystalline, which would have raised the viscosity of the initial melt by 1-2 orders of magnitude, which may not be enough to cause fragmentation.

  3. 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.

  4. 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

  5. Restoration of Endodontically Treated Teeth Review and Treatment Recommendations

    PubMed Central

    Slutzky-Goldberg, Iris; Slutzky, Hagay; Gorfil, Colin; Smidt, Ami

    2009-01-01

    Coronal restorations and posts can positively influence the long-term prognosis of teeth following root canal therapy. Final sealing the canal by placing an appropriate post and core will minimize leakage of oral fluids and bacteria into the periradicular area and is recommended as soon as possible after completion of root canal filling. Glass ionomer or MTA placed over the residual root canal filling after post space preparation may be effective to prevent bacterial leakage. A ferrule of 1-2 mm of tooth tissue coronal to the finish line of the crown significantly improves the fracture resistance of the tooth and is more important than the type of the material the core and post are made of. PMID:20309408

  6. 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.

  7. 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

  8. 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

  9. Psoriasiform Drug Eruption Caused by Abatacept: Immunohistochemical Investigation of STAT Signaling

    PubMed Central

    Tanita, Kayo; Fujimura, Taku; Kakizaki, Aya; Furudate, Sadanori; Kusakari, Yoshiyuki; Aiba, Setsuya

    2015-01-01

    Abatacept is a biological immune modifier that is used for the treatment of rheumatoid arthritis. Although psoriasiform drug eruption is reported as one of the cutaneous adverse effects of abatacept, the precise mechanisms are not fully understood. In this report, we describe a 65-year-old Japanese man with psoriasiform drug eruption caused by abatacept. Interestingly, immunohistochemical staining revealed that the epidermal keratinocytes in the basal layer and lower layers of the stratum spinosum were positive for pSTAT3, partially positive for pSTAT1 and negative for pSTAT6, which is similar to conventional psoriasis vulgaris. Our present study suggests that psoriasiform drug eruption caused by abatacept might develop by similar immunological mechanisms as those of psoriasis vulgaris. PMID:26351425

  10. Mass-independent sulfur isotopic compositions in stratospheric volcanic eruptions.

    PubMed

    Baroni, Mélanie; Thiemens, Mark H; Delmas, Robert J; Savarino, Joël

    2007-01-05

    The observed mass-independent sulfur isotopic composition (Delta33S) of volcanic sulfate from the Agung (March 1963) and Pinatubo (June 1991) eruptions recorded in the Antarctic snow provides a mechanism for documenting stratospheric events. The sign of Delta33S changes over time from an initial positive component to a negative value. Delta33S is created during photochemical oxidation of sulfur dioxide to sulfuric acid on a monthly time scale, which indicates a fast process. The reproducibility of the results reveals that Delta33S is a reliable tracer to chemically identify atmospheric processes involved during stratospheric volcanism.

  11. Study New Pregress on Volcanic Phreatomagmatic Eruption

    NASA Astrophysics Data System (ADS)

    Sun, Q.; Fan, Q.; Li, N.

    2007-12-01

    As an essential and important type of volcanic eruption on earth, phreatomagmatic eruption is characterized by groundwater-related explosive eruption and subsequent base surge deposit and maar lakes. Base surge deposit and maar lakes are widely distributed all over the world, and also in the Northeast China and the southern China. Study of phreatomagmatic eruption maybe dated back to 1921, and in the following over 80 years, many works have been done on phreatomagmatic eruption, using various of methods of volcanic geology, petrology, sedimentology, physical volcanology and digital modeling, to discuss its origin and mechanism. In this paper, we focus on the geological feature of the base surge deposit and dynamic mechanism of the phreatomagmatic eruption. When ascending basaltic magma meets with ground ( surface ) water, violent explosion would occur, this action was called phreatomagmatic eruption. The main product of this kind of eruption are maars and base surge. As to the base surge, it has long been treated as sedimentary tuff by mistake. Usually, base surge is distributed around maar, different from the distribution of sedimentary tuff. Typical phenomena of base surge caused by phreatomagmatic eruption can be observed through the detail field work, such as large-scale and low-angle cross-bedding, slaty-bedding, current-bedding and distal facies accretionary lapilli. In order to explain the dynamic mechanism of phreatomagmatic eruption thoroughly, we propose a simple model in this paper in light of the elasticity theory. Some conclusions can be drawn as follows: the larger the radius of maar, the larger the explosive wallop needed for the formation of maar is; provided that the radius of maar and depth of explosive point are limited, then the larger the area of contact surface between magma and groundwater, the stronger the explosive energy will be; if the explosive energy and area of explosive point are restricted, the larger the radius of maar, the greater

  12. Seismic recording of the Anatahan eruption

    NASA Astrophysics Data System (ADS)

    Pozgay, S. H.; Wiens, D. A.; Shore, P. J.; Sauter, A.; Camacho, J. T.

    2003-12-01

    The first historic eruption of Anatahan volcano was fortuitously recorded by a broadband PASSCAL seismograph installed on the island only 4 days prior to the eruption. Although covered by ash during the eruption, the seismograph continued to operate throughout the main two month period of activity on Anatahan. This seismograph, located about 6 km west of the active eastern crater, as well as a seismograph installed on Sarigan about 45 km to the north, provide a continuous record of activity during the eruption. We have manually analyzed and visually picked arrivals from the 14 day period beginning 4 days prior to the eruption, and we have implemented an automatic event identification algorithm for the rest of the eruption period that has been calibrated relative to the manually processed data. In addition, we have located many of the larger volcano tectonic (VT) earthquakes using the P and S wave arrivals at Anatahan and Sarigan as well as P wave polarization data. Although these locations are not highly accurate they serve to delineate the general spatial progression of the earthquake activity. No earthquakes occurred in the crater region during the 4 days prior to the eruption. The only significant precursory earthquake activity was a swarm of events on May 8 that were located about 15 km northeast of the island and significantly deeper than events directly associated with the eruption. The first VT event from Anatahan itself was recorded at about 02:00 hrs GMT on May 10. The number of events per hour increases dramatically between 02:00 and 07:00 GMT. A period of nearly continuous earthquake activity commences at about 06:20 GMT which corresponds well with the eruption time of 07:30 GMT estimated by the Volcanic Ash Advisory Center from satellite photos of the ash cloud. After about 36 hours of intense earthquake activity, the number of discrete earthquakes declined, and were replaced by nearly continuous volcanic tremor. Much of the later part of the eruption

  13. Volcano Monitoring and Eruption Response in Japan

    NASA Astrophysics Data System (ADS)

    Nakada, S.; Morita, Y.

    2010-12-01

    Although the start of eruption was forecasted at Miyakejima in June 2000, its change since then was largely different from what we expected; the countermeasures always became one step behind. There was a sudden lateral intrusion of the enormous amount magma as far as 30 km away from the volcano. The failure in forecasting comes partly from insufficient consideration of the eruption history and simple analogy of recent, near-steady state eruption events. The 2000 eruption may be reappearance of that of 2.5 ka at Miyakejima. The national project of eruption prediction researches has focused on seismological and geomagnetic investigations to detect the temporal change in the subsurface structure for active volcanoes, together with repeated, multidiscipline intensive observation. These were considered important to understand magma storage and movement, to evaluate the eruption potential, and to forecast the future eruption. Although direct detection of the magma chamber was incomplete, the convex distribution of dense material beneath the summit became common throughout examined volcanoes. It became clear that the part consists of the dike swarms through the conduit drilling project at Unzen. Understanding of the velocity structure by the seismic experiments was very useful to determine the detail location of volcano earthquakes in those volcanoes. Furthermore, combination of seismic, geodetic, geomagnetic and petrological investigations provided us a better imaging of the subsurface structure of several volcanoes. New technology such as the cosmic-ray (muon) radiography, which made the volcano interior visible, will give us the important information on magma ascent in the shallowest part of volcano. Recently, seismological and geodetic monitoring at densely-located observation sites makes possible to image the magma’s ascent and accumulation under volcanoes from the middle to upper crust. This process, of course, needs knowledge on the subsurface structure (depth of

  14. 3-D imaging in post-traumatic malformation and eruptive disturbance in permanent incisors: a case report.

    PubMed

    Sahai, Sharad; Kaveriappa, Sushma; Arora, Honey; Aggarwal, Bharat

    2011-12-01

    Injury to the primary dentition is one of the common problems of childhood. Disturbances during crown development of the permanent teeth result in morphologic alterations. This case report highlights the role of 3-D imaging when conventional dental radiographs are not enough to answer our clinical questions regarding future eruptive disturbances. 3-D imaging can many times give us a definitive diagnosis and improve the treatment planning after early injuries in the deciduous dentition. The current status of multislice computed tomography (CT) and cone beam CT (CBCT) as diagnostic tools in pediatric dental population is also discussed briefly.

  15. BONES, TEETH AND GENES: A Genomic Homage to Harry Sicher’s “Axial Movement of Teeth”

    PubMed Central

    Holliday, Sean; Schneider, Bernard; Galang, Maria Therese S.; Fukui, Tadayoshi; Yamane, Akira; Luan, Xianghong; Diekwisch, Thomas G.H.

    2009-01-01

    Aims We have used the model of the un-opposed rodent molar to study morphologic and genetic mechanisms of tooth eruption. Methods Left maxillary molar teeth of 12-day old Swiss-Webster mice were extracted under anesthesia and mandibular molars were allowed to super-erupt. To trace areas of tissue remodeling and to determine areas of new tissue formation, mice were injected with fluorescent dyes, tetracycline, alizarin red, and calcein blue. Subsequent to sacrifice, mandible tissue blocks were prepared for ultrathin ground sections, fluorescent microscopy, and von Kossa’s mineral detection procedure. A second set of specimen was prepared for RNA extraction and microarray analysis. Results Our data established significant eruption of first and second mandibular mouse molars following complete extraction of antagonists by 0.13 mm after 12 days. Labeled tissue sections revealed significant amounts of new bone and cementum apposition on the un-opposed side compared to the control side as revealed by fluorescent markers and ultrathin ground sections. Microarray transcript level comparisons between the experimental and the control group demonstrated significant (more than 2-fold) increase in gene expression of elastin and tenascin C extracellular matrix proteins; brevican, lumican, and biglycan proteoglycans; as well as fibroblast growth factor 9. Conclusion In this study we have established the un-opposed mouse molar as a model to study tissue dynamics during the axial movement of teeth. Our data indicated significant new formation of bone and cementum in tandem with increased expression of extracellular matrix-related genes. PMID:15794043

  16. 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

  17. Volcano shapes, entropies, and eruption probabilities

    NASA Astrophysics Data System (ADS)

    Gudmundsson, Agust; Mohajeri, Nahid

    2014-05-01

    We propose that the shapes of polygenetic volcanic edifices reflect the shapes of the associated probability distributions of eruptions. In this view, the peak of a given volcanic edifice coincides roughly with the peak of the probability (or frequency) distribution of its eruptions. The broadness and slopes of the edifices vary widely, however. The shapes of volcanic edifices can be approximated by various distributions, either discrete (binning or histogram approximation) or continuous. For a volcano shape (profile) approximated by a normal curve, for example, the broadness would be reflected in its standard deviation (spread). Entropy (S) of a discrete probability distribution is a measure of the absolute uncertainty as to the next outcome/message: in this case, the uncertainty as to time and place of the next eruption. A uniform discrete distribution (all bins of equal height), representing a flat volcanic field or zone, has the largest entropy or uncertainty. For continuous distributions, we use differential entropy, which is a measure of relative uncertainty, or uncertainty change, rather than absolute uncertainty. Volcano shapes can be approximated by various distributions, from which the entropies and thus the uncertainties as regards future eruptions can be calculated. We use the Gibbs-Shannon formula for the discrete entropies and the analogues general formula for the differential entropies and compare their usefulness for assessing the probabilities of eruptions in volcanoes. We relate the entropies to the work done by the volcano during an eruption using the Helmholtz free energy. Many factors other than the frequency of eruptions determine the shape of a volcano. These include erosion, landslides, and the properties of the erupted materials (including their angle of repose). The exact functional relation between the volcano shape and the eruption probability distribution must be explored for individual volcanoes but, once established, can be used to

  18. [Complications of injuries to deciduous teeth].

    PubMed

    Oka, A E; N'Cho, K J; Bakayoko-Ly, R

    2003-03-01

    The traumatisms of the temporary teeth are very frequent. They are bound to the acquirement of the march, to the games, to the sport and to the accidents of the public way. Favoured by the presence one improved proalveoly, they constitute a dental emergency of makes some important risks of complications. Indeed, these traumatisms, in case of belated conference and/or of maladjusted treatment or conducted pain, could induce some complications and have some aesthetic and functional after effects on the dental germ underlying. Some of these complications observed in some patients are stakes in evidence by some iconographic illustrations.

  19. Numerical Simulation Of Cutting Of Gear Teeth

    NASA Technical Reports Server (NTRS)

    Oswald, Fred B.; Huston, Ronald L.; Mavriplis, Dimitrios

    1994-01-01

    Shapes of gear teeth produced by gear cutters of specified shape simulated computationally, according to approach based on principles of differential geometry. Results of computer simulation displayed as computer graphics and/or used in analyses of design, manufacturing, and performance of gears. Applicable to both standard and non-standard gear-tooth forms. Accelerates and facilitates analysis of alternative designs of gears and cutters. Simulation extended to study generation of surfaces other than gears. Applied to cams, bearings, and surfaces of arbitrary rolling elements as well as to gears. Possible to develop analogous procedures for simulating manufacture of skin surfaces like automobile fenders, airfoils, and ship hulls.

  20. Treatment of experimental furcation perforations with mineral trioxide aggregate, platelet rich plasma or platelet rich fibrin in dogs' teeth.

    PubMed

    Tawfik, Hosam E; Abu-Seida, Ashraf M; Hashem, Ahmed A; El-Khawlani, Mohammed M

    2016-06-01

    This work evaluates the effect of mineral trioxide aggregate (MTA), platelet rich plasma (PRP) or platelet rich fibrin (PRF) on healing of non-contaminated and contaminated furcation perforations. A total of 192 teeth of 12 dogs was divided into three equal groups according to evaluation period. Each group was further subdivided into MTA, PRP, PRF, negative and positive control subgroups. Each experimental subgroup was further subdivided according to perforation status into non-contaminated and contaminated subdivisions. Root canal therapy was carried out and furcation perforation was made in all teeth except in negative control subgroup. The furcation perforation was repaired immediately in subdivision (1) and after 4 weeks in subdivision (2). The change in vertical bone loss was measured by radiography. Inflammatory cell count, cemental deposition, new bone formation, bone resorption and epithelial proliferation were assessed. Both PRP and PRF demonstrated statistically significant reduction in vertical bone loss and inflammatory cell count than MTA. No significant difference was found between MTA, PRP and PRF in cemental deposition, new bone formation, bone resorption and epithelial proliferation. The non-contaminated teeth demonstrated better treatment outcomes than the contaminated teeth. In conclusion, PRP and PRF are successful treatment options for repairing of furcation perforation in both non-contaminated and contaminated teeth in dogs with superior outcomes in non contaminated teeth.

  1. A FLUX ROPE ERUPTION TRIGGERED BY JETS

    SciTech Connect

    Guo Juan; Zhang Hongqi; Deng Yuanyong; Lin Jiaben; Su Jiangtao; Liu Yu

    2010-03-10

    We present an observation of a filament eruption caused by recurrent chromospheric plasma injections (surges/jets) on 2006 July 6. The filament eruption was associated with an M2.5 two-ribbon flare and a coronal mass ejection (CME). There was a light bridge in the umbra of the main sunspot of NOAA 10898; one end of the filament was terminated at the region close to the light bridge, and recurrent surges were observed to be ejected from the light bridge. The surges occurred intermittently for about 8 hr before the filament eruption, and finally a clear jet was found at the light bridge to trigger the filament eruption. We analyzed the evolutions of the relative darkness of the filament and the loaded mass by the continuous surges quantitatively. It was found that as the occurrence of the surges, the relative darkness of the filament body continued growing for about 3-4 hr, reached its maximum, and kept stable for more than 2 hr until it erupted. If suppose 50% of the ejected mass by the surges could be trapped by the filament channel, then the total loaded mass into the filament channelwill be about 0.57x10{sup 16} g with a momentum of 0.57x10{sup 22} g cm s{sup -1} by 08:08 UT, which is a non-negligible effect on the stability of the filament. Based on the observations, we present a model showing the important role that recurrent chromospheric mass injection play in the evolution and eruption of a flux rope. Our study confirms that the surge activities can efficiently supply the necessary material for some filament formation. Furthermore, our study indicates that the continuous mass with momentum loaded by the surge activities to the filament channel could make the filament unstable and cause it to erupt.

  2. Magma chamber dynamics and Vesuvius eruption forecasting

    NASA Astrophysics Data System (ADS)

    Dobran, F.

    2003-04-01

    Magma is continuously or periodically refilling an active volcano and its eruption depends on the mechanical, fluid, thermal, and chemical aspects of the magma storage region and its surroundings. A cyclically loaded and unloaded system can fail from a weakness in the system or its surroundings, and the fluctuating stresses can produce system failures at stress levels that are considerably below the yield strength of the material. Magma in a fractured rock system within a volcano is unstable and propagates toward the surface with the rate depending on the state of the system defined by the inertia, gravity, friction, and permeability parameters of magma and its source region. Cyclic loading and unloading of magma from a reservoir caused by small- or medium-scale eruptions of Vesuvius can produce catastrophic plinian eruptions because of the structural failure of the system and the quiescent periods between these eruptions increase with time until the next eruption cycle which will be plinian or subplinian and will occur with a very high probability this century. Such a system behavior is predicted by a Global Volcanic Simulator of Vesuvius developed for simulating different eruption scenarios for the purpose of urban planning the territory, reducing the number of people residing too close to the cone of the volcano, and providing safety to those beyond about 5 km radius of the crater. The magma chamber model of the simulator employs a thermomechanical model that includes magma inflow and outflow from the chamber, heat and mass transfer between the chamber and its surroundings, and thermoelastoplastic deformation of the shell surrounding the magma source region. These magma chamber, magma ascent, and pyroclastic dispersion models and Vesuvius eruption forecasting are described in Dobran, F., VOLCANIC PROCESSES, Kluwer Academic/Plenum Publishers, 2001, 590 pp.

  3. Characterize Eruptive Processes at Yucca Mountain, Nevada

    SciTech Connect

    G. Valentine

    2001-12-20

    This Analysis/Model Report (AMR), ''Characterize Eruptive Processes at Yucca Mountain, Nevada'', presents information about natural volcanic systems and the parameters that can be used to model their behavior. This information is used to develop parameter-value distributions appropriate for analysis of the consequences of volcanic eruptions through a potential repository at Yucca Mountain. Many aspects of this work are aimed at resolution of the Igneous Activity Key Technical Issue (KTI) as identified by the Nuclear Regulatory Commission (NRC 1998, p. 3), Subissues 1 and 2, which address the probability and consequence of igneous activity at the proposed repository site, respectively. Within the framework of the Disruptive Events Process Model Report (PMR), this AMR provides information for the calculations in two other AMRs ; parameters described herein are directly used in calculations in these reports and will be used in Total System Performance Assessment (TSPA). Compilation of this AMR was conducted as defined in the Development Plan, except as noted. The report begins with considerations of the geometry of volcanic feeder systems, which are of primary importance in predicting how much of a potential repository would be affected by an eruption. This discussion is followed by one of the physical and chemical properties of the magmas, which influences both eruptive styles and mechanisms for interaction with radioactive waste packages. Eruptive processes including the ascent velocity of magma at depth, the onset of bubble nucleation and growth in the rising magmas, magma fragmentation, and velocity of the resulting gas-particle mixture are then discussed. The duration of eruptions, their power output, and mass discharge rates are also described. The next section summarizes geologic constraints regarding the interaction between magma and waste packages. Finally, they discuss bulk grain size produced by relevant explosive eruptions and grain shapes.

  4. Prediction of canine and premolar size using the widths of various permanent teeth combinations: A cross-sectional study

    PubMed Central

    Vanjari, Kalasandhya; Nuvvula, Sivakumar; Kamatham, Rekhalakshmi

    2015-01-01

    Aims: To suggest the best predictor/s for determining the mesio-distal widths (MDWs) of canines (C) and premolars (Ps), and propose regression equation/s for hitherto unreported population. Methods: Impressions of maxillary and mandibular arches were made for 201 children (100 boys and 101 girls; age range: 11–15 years) who met the inclusion criteria and poured with dental stone. The maximum MDWs of all the permanent teeth were measured using digital vernier caliper. Thirty-three possible combinations (patterns) of permanent maxillary and mandibular first molars, central and lateral incisors were framed and correlated with MDWs of C and Ps using Pearson correlation test. Results: There were significant correlations between the considered patterns and MDWs of C and Ps, with difference noted between girls (range of r: 0.34–0.66) and boys (range of r: 0.28–0.77). Simple linear and multiple regression equations for boys, girls, and combined sample were determined to predict MDW of C and Ps in both the arches. Conclusions: The accuracy of prediction improved considerably with the inclusion of as many teeth as possible in the regression equations. The newly proposed equations based on the erupted teeth may be considered clinically useful for space analysis in the considered population. PMID:26604576

  5. 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

  6. Partial pulpotomy in young permanent teeth with deep carious lesions.

    PubMed

    Mejàre, I; Cvek, M

    1993-12-01

    The material comprised 37 young posterior teeth with deep carious lesions and exposed pulps, treated with partial pulpotomy and dressed with calcium hydroxide. The teeth were divided into two groups. Group 1 consisted of 31 teeth with no clinical or radiographic symptoms before treatment, Group 2 of 6 teeth with temporary pain, widened periodontal space periapically and/or productive osteitis, i.e. increased density of the surrounding alveolar bone. After an observation time of 24 to 140 months (mean = 56 months), healing had occurred in 29 of 31 teeth in Group 1 (93.5%) and in 4 of 6 teeth in Group 2. It was concluded that the present, as well as previously reported results indicate that partial pulpotomy may be an adequate treatment for young permanent molars with a carious exposure, although more studies are needed before the treatment can be recommended for routine clinical use.

  7. Histological appearance of postmortem pink teeth: Report of two cases.

    PubMed

    Gowda, Bk Charan; Sivapathasundharam, B; Chatterji, Ananjan; Chatterji, B L

    2015-01-01

    This article presents images and histological changes in the dentin of two cases involving posmortem pink teeth. Postmortem pink teeth were noted among two deceased male individuals. Pink teeth were noted during autopsy examination after twelve days in one corpse, and eight days following death in the second case. During the examination decomposition and putrefaction of the body was noted. Cause of death was drowning in one case and haemorrhages and shock in another. A central incisor tooth was obtained from each body. Both teeth exhibited a pink appearance and the intensity was more pronounced in the cervical region. Although pink teeth can be noted in death due to asphyxia, carbon monoxide poisoning and so on, it is necessary to study the exact role behind the appearance of pink teeth and try to incorporate the finding medico legally.

  8. Coronal reconstruction following anterior teeth traumatism: multidisciplinary treatment.

    PubMed

    Cohen-Carneiro, Flavio; Sponchiado, Emilio Carlos; Garcia, Lucas do Fonseca Roberti; Yurtsever, Fikriye Viga; Pontes, Danielson Guedes; Sena, Amilen

    2013-08-01

    This study describes how periodontology, endodontology, and dentistry were integrated for the coronal reconstruction of anterior teeth extensively destroyed by dental trauma. A 15-year-old girl suffered a bicycle accident that resulted in the fracture of teeth No. 8 and 9. Clinical and radiographic examinations confirmed coronal fracture in both teeth, in addition to compromised pulp vitality, invasion of the biologic periodontal space, and loss of coronal space due to mesialization of the neighboring teeth. The protocol consisted of endodontic treatment for the fractured teeth, periodontal surgery to augment the clinical crown and gingival recontouring, intracanal cementation of esthetic glass fiber posts, and coronal reconstruction with resin composite. At a longitudinal follow-up visit 1 year later, clinical and radiographic examinations revealed successful rehabilitation of the fractured teeth.

  9. Effect of palatal form on movement of teeth during processing of complete denture prosthesis: An in-vitro study

    PubMed Central

    Babu, Sumanth; Manjunath, Shaurya; Vajawat, Mayuri

    2016-01-01

    Aim: The aim of this in-vitro study was to assess the influence of shallow and deep palatal forms on the movement of teeth during the processing of complete denture prosthesis. Materials and Methods: Maxillary casts with shallow and deep palatal forms were selected and duplicated to make 10 casts of each palatal form. Base plates were constructed and teeth were arranged in their anatomic positions. Metal pins with true apex were placed on the central groove of the right and left first molars and one on the incisive papilla area as a reference point. Casts were scanned using i-CAT Vision Q 1.9 (i-CAT cone beam 3D dental imaging system by Imaging Sciences International, PA, USA), which has 360° rotational tomography. The distances between the apices of metallic pin inserts on the teeth and fitted point of reference were recorded in buccopalatal axes at waxed up stage, after deflasking, and after finishing and polishing. Results: Results showed a statistically significant movement of teeth in shallow and deep palatal forms during all stages of complete denture processing. In shallow palatal form dentures, there was a significant tooth movement in palatal direction between Stages 1 and 2 (P ≤ 0.05) and buccal movement between Stages 2 and 3. In deep palatal form dentures, teeth showed a statistically significant (P ≤ 0.05) movement in buccal direction during all stages of denture processing. Conclusion: Teeth showed significant movement during processing of acrylic resin dentures. Overall, the movement of teeth in shallow palatal form dentures was in palatal direction, whereas in deep palatal form dentures, the movement of teeth was in buccal direction. PMID:27041898

  10. Long-term evaluation of teeth and implants during the periodic maintenance in patients with viral liver disease

    PubMed Central

    2016-01-01

    PURPOSE This study was designed to investigate the maintenance of teeth and implants in patients with viral liver disease. MATERIALS AND METHODS 316 patients without any significant systemic disease were selected as a control group. Liver disease group was consisted of 230 patients. Necessary data were collected using clinical records and panoramic radiographs. Then, the patients were subdivided into 2 groups based on the type of active dental therapy received before maintenance period (Pre-Tx). Analysis for finding statistically significant difference was performed based on the need for re-treatment of active dental therapy (Re-Tx) and change in the number of teeth (N-teeth) and implants (N-implants). RESULTS Comparing to control group, the patients with liver disease showed higher value on N-teeth, N-implants, and Re-Tx. Statistically significant differences were found on N-teeth (P=.000) and Re-Tx (P=.000) in patients with non-surgical Pre-Tx. Analysis based on severity of liver disease showed that N-teeth and Re-Tx were directly related to severity of liver disease regardless of received type of Pre-Tx. Significant differences were found on N-teeth (P=.003) and Re-Tx (P=.044) in patients with non-surgical Pre-Tx. CONCLUSION In this study, it was concluded that liver disease might influence the loss of teeth and cause the relapse of dental disease during maintenance period in patients. A significant positive relationship between tooth and implant loss and severity of liver disease seems to exist. PMID:27555902

  11. Prevalence and correlates of perceived teeth health status and oral health behavior among school-going adolescents in Cambodia

    PubMed Central

    Peltzer, Karl; Tepirou, Chher; Pengpid, Supa

    2016-01-01

    ABSTRACT The purpose of the study was to investigate perceived teeth health status and oral health behavior, as well as their correlates, among adolescents in Cambodia. The analysis included 3806 Cambodian school children (mean age 15.7 years, SD=1.8 years) who took part in the “Global School-based Student Health Survey” (GSHS) in 2013. Overall, 7.8% of the students reported poor perceived teeth status, 18.0% had missed school in the past year because of a toothache, 26.7% engaged in combined oral health behavior (brushing teeth twice daily or more often = 79.8%, using fluoride toothpaste = 59.9%, and drinking soft drinks less than once a day = 53.6%), and 59.9% had never visited a dentist for a routine examination or other dental work. In the multivariate logistic regression analysis, older age, being female, missing school because of a toothache, having a toothache in the past 12 months, poor oral health behavior and sedentary leisure time were associated with poor perceived teeth status. Older age, good perceived teeth status, having had a dental check-up, washing hands before eating and after toilet use, and not eating fast food were associated with a positive oral health behavior (brushing teeth twice daily or more often, using fluoride toothpaste, and drinking soft drinks less than once a day). Significant proportions of poor perceived teeth status and poor oral health behavior were found among school children in Cambodia. Various risk factors (sociodemographic, dental variables, general health risk behaviors) for perceived poor teeth status, oral health behavior and never having had a dental check-up were identified, which can be utilized for intervention programs. PMID:28008205

  12. Beauty and the teeth: perception of tooth color and its influence on the overall judgment of facial attractiveness.

    PubMed

    Höfel, Lea; Lange, Matthias; Jacobsen, Thomas

    2007-08-01

    This study investigated the influence of changes in tooth color on judgments of facial attractiveness. Standardized photographs were presented, and teeth were digitally manipulated (main categories: original, whitened, colored; filler category: impaired). Participants were instructed to evaluate the faces for attractiveness. Additionally, they were asked to name facial features they found either positive or negative with regard to attractiveness. Whitened teeth were mentioned more often in a positive way but did not improve participants' assessment of attractiveness. A colored tooth did not attract attention, and the attractiveness judgment did not worsen. Tooth color is thus not necessarily perceived and does not have a major impact on facial attractiveness.

  13. Characteristics of stem cells from human exfoliated deciduous teeth (SHED) from intact cryopreserved deciduous teeth.

    PubMed

    Lee, Hyo-Seol; Jeon, Mijeong; Jeon, Mi Jung; Kim, Seong-Oh; Kim, Seung-Hye; Lee, Jae-Ho; Lee, Jea-Ho; Ahn, Su-Jin; Shin, Yooseok; Song, Je Seon

    2015-12-01

    The aim of this study is to compare the characteristics of stem cells derived from human exfoliated deciduous teeth (SHED) from cryopreserved intact deciduous teeth with those of fresh SHED. In total, 20 exfoliated deciduous teeth were randomly divided into a fresh group (f-SHED; n = 11) and cryopreserved group (c-SHED; n = 9; stored for 1-8 months). Following thawing and separation of the pulp, the SHED cells were cultured, and the characteristics as mesenchymal stem cells were investigated using proliferation assays, cell-cycle analysis, colony-forming unit-fibroblast (CFU-F) assays, and flow cytometry analyses. Furthermore, differentiation into adipogenic and osteogenic lineages was investigated in vitro as well as in vivo via transplantation in mice. We found no significant differences between the two groups in the proliferation analyses, in the expression of mesenchymal stem cell markers, or in the adipogenic and osteogenic differentiation in vitro (p < 0.05). Furthermore, the in vivo transplantation results showed no significant differences in the quantity of bone tissue that formed or in histochemistry performance (p < 0.05). In conclusion, cryopreservation of intact exfoliated deciduous teeth appears to be a useful method for preserving SHED.

  14. [Professional teeth cleaning is more than plaque removal].

    PubMed

    van Foreest, Andries

    2006-12-15

    Telephone enquiries about the cost of cleaning the teeth of cats or dogs cannot be answered without clinical investigation of the animal and oral examination under sedation or anaesthesia. This article describes the procedures used during the professional cleaning of the teeth of companion animals. An itemized list of procedures and their cost means that the era of "shopping around" for teeth cleaning is past.

  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. Eruption Mechanism of the 10th Century Eruption in Baitoushan Volcano, China/North Korea

    NASA Astrophysics Data System (ADS)

    Shimano, T.; Miyamoto, T.; Nakagawa, M.; Ban, M.; Maeno, F.; Nishimoto, J.; Jien, X.; Taniguchi, H.

    2005-12-01

    Baitoushan volcano, China/North Korea, is one of the most active volcanoes in Northeastern Asia, and the 10th century eruption was the most voluminous eruption in the world in recent 2000 years. The sequence of the eruption reconstructed recently consists mainly of 6 units of deposits (Miyamoto et al., 2004); plinian airfall (unit B), large pyroclastic flow (unit C), plinian airfall with some intra- plinian pyroclastic flows (unit D), sub-plinian airfall (unit E), and large pyroclastic flow (unit F) with base surge (unit G) in ascending order. The magma erupted during steady eruption in earlier phase was comendite (unit B-C; Phase 1), whereas the magma during fluctuating eruptions in later phase is characterized by trachyte to trachyandesite with various amount of comendite (unit D-G; Phase 2). The wide variety in composition and occurrence of banded pumices strongly indicate mixing or mingling of the two magmas just prior to or during the eruption. The initial water contents had been determined for comendite by melt inclusion analyses (ca. 5.2 wt.%; Horn and Schmincke, 2000). Although the initial water content of the trachytic magma has not been correctly determined yet, the reported water contents of trachytic melt inclusions are lower (3-4 wt.%) than those of comenditic melt (Horn and Schmincke, 2000). We investigated juvenile materials of the eruption sequentially in terms of vesicularity, H2O content in matrix glass and textural characteristics. The vesicularity of pumices are generally high (>0.75) for all units. The residual water contents of the comenditic pumices during Phase 1 are relatively uniform (1.6 wt.%), whereas those of the trachytic scoria during Phase 2 and gray pumices during Phase 1 are low (ca. 0.7-1.3 wt.%). These facts may indicate that the difference in the initial water content, rather than the ascent mechanism of magma, controls the steadiness or fluctuation in eruption styles and the mass flux during the eruption.

  17. Homologous prominence non-radial eruptions: A case study

    NASA Astrophysics Data System (ADS)

    Duchlev, P.; Koleva, K.; Madjarska, M. S.; Dechev, M.

    2016-10-01

    The present study provides important details on homologous eruptions of a solar prominence that occurred in active region NOAA 10904 on 2006 August 22. We report on the pre-eruptive phase of the homologous feature as well as the kinematics and the morphology of a forth from a series of prominence eruptions that is critical in defining the nature of the previous consecutive eruptions. The evolution of the overlying coronal field during homologous eruptions is discussed and a new observational criterion for homologous eruptions is provided. We find a distinctive sequence of three activation periods each of them containing pre-eruptive precursors such as a brightening and enlarging of the prominence body followed by small surge-like ejections from its southern end observed in the radio 17 GHz. We analyse a fourth eruption that clearly indicates a full reformation of the prominence after the third eruption. The fourth eruption although occurring 11 h later has an identical morphology, the same angle of propagation with respect to the radial direction, as well as similar kinematic evolution as the previous three eruptions. We find an important feature of the homologous eruptive prominence sequence that is the maximum height increase of each consecutive eruption. The present analysis establishes that all four eruptions observed in Hα are of confined type with the third eruption undergoing a thermal disappearance during its eruptive phase. We suggest that the observation of the same direction of the magnetic flux rope (MFR) ejections can be consider as an additional observational criterion for MFR homology. This observational indication for homologous eruptions is important, especially in the case of events of typical or poorly distinguishable morphology of eruptive solar phenomena.

  18. Eruptive history and magmatic stability of Erebus volcano, Antarctica: Insights from englacial tephra

    NASA Astrophysics Data System (ADS)

    Iverson, N. A.; Kyle, P. R.; Dunbar, N. W.; Pearce, N. J.

    2012-12-01

    microprobe and laser ablation ICP-MS. Glass compositions are phonolite and remarkably uniform and statistically similar to volcanic bombs erupted over the past 40 years. Analyses of glass in ash and lava bombs show that Erebus magmas have not changed in composition over the past 40ka making it impossible to fingerprint the individual tephra and correlate them between blue ice patches. Due to this similarity, we rely on stratigraphic position, age (determined by the 40Ar/39Ar dating method), shard morphology and grain size to understand the eruptive history of Erebus. The uniform glass composition implies that the phonolite magma has evolved, fractionated from a parental basanite and crystallized in the same manner without change throughout the Holocene, suggesting long-term stability of the Erebus magmatic system.

  19. Restoring primary anterior teeth: updated for 2014.

    PubMed

    Waggoner, William F

    2015-01-01

    The purpose of this paper was to review the current literature associated with the techniques and materials for the restoration of primary anterior teeth and make clinical recommendations based upon the available literature. A variety of esthetic restorative materials are available to utilize for restoring primary incisors. Awareness of the specific strengths, weakness, and properties of each material can 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. 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 crowns that are luted onto the tooth and are either some type of stainless steel or zirconia crown. There is insufficient controlled, clinical data to suggest that one type of restoration is superior to another. Operator preferences, esthetic demands by parents, the child's behavior, the amount of tooth structure remaining, and moisture and hemorrhage control are all variables that affect the decision and ultimate outcome of whatever restorative solution is chosen.

  20. Applying tribology to teeth of hoofed mammals.

    PubMed

    Schulz, Ellen; Calandra, Ivan; Kaiser, Thomas M

    2010-01-01

    Mammals inhabit all types of environments and have evolved chewing systems capable of processing a huge variety of structurally diverse food components. Surface textures of cheek teeth should thus reflect the mechanisms of wear as well as the functional traits involved. We employed surface textures parameters from ISO/DIS 25178 and scale-sensitive fractal analysis (SSFA) to quantify dental wear in herbivorous mammals at the level of an individual wear enamel facet. We evaluated cheek dentitions of two grazing ungulates: the Blue Wildebeest (Connochaetes taurinus) and the Grevy's Zebra (Equus grevyi). Both inhabit the east African grassland savanna habitat, but they belong to fundamentally different taxonomic units. We tested the hypothesis that the foregut fermenting wildebeest and the hindgut fermenting zebra show functional traits in their dentitions that relate to their specific mode of food-composition processing and digestion. In general, surface texture parameters from SSFA as well as ISO/DIS 25178 indicated that individual enamel ridges acting as crushing blades and individual wear facets of upper cheek teeth are significantly different in surface textures in the zebra when compared with the wildebeest. We interpreted the complexity and anisotropy signals to be clearly related to the brittle, dry grass component in the diet of the zebra, unlike the wildebeest, which ingests a more heterogeneous diet including fresh grass and herbs. Thus, SSFA and ISO parameters allow distinctions within the subtle dietary strategies that evolved in herbivorous ungulates with fundamentally different systematic affinities but which exploit a similar dietary niche.

  1. Factors influencing trace element composition in human teeth

    SciTech Connect

    Tandon, L.; Iyengar, G.V.

    1997-12-01

    The authors recently compiled and reviewed the literature published in or after 1978 for 45 major, minor, and trace elements in human teeth as a part of an International Atomic Energy Agency (IAEA) study. The purpose of this paper is to discuss the various factors that influence the concentration levels of certain trace elements in human teeth. The sampling practices and analytical techniques that are applicable for trace element analysis are also discussed. It is also our intention to identify reference range of values, where data permit such conclusions. The scrutiny was designed to identify only the healthy permanent teeth, and values from teeth with fillings, caries, or periodontal diseases were eliminated.

  2. Soft dentin results in unique flexible teeth in scraping catfishes.

    PubMed

    Geerinckx, Tom; Huysseune, Ann; Boone, Matthieu; Claeys, Myriam; Couvreur, Marjolein; De Kegel, Barbara; Mast, Peter; Van Hoorebeke, Luc; Verbeken, Kim; Adriaens, Dominique

    2012-01-01

    Teeth are generally used for actions in which they experience mainly compressive forces acting toward the base. The ordered tooth enamel(oid) and dentin structures contribute to the high compressive strength but also to the minor shear and tensile strengths. Some vertebrates, however, use their teeth for scraping, with teeth experiencing forces directed mostly normal to their long axis. Some scraping suckermouth catfishes (Loricariidae) even appear to have flexible teeth, which have not been found in any other vertebrate taxon. Considering the mineralized nature of tooth tissues, the notion of flexible teeth seems paradoxical. We studied teeth of five species, testing and measuring tooth flexibility, and investigating tooth (micro)structure using transmission electron microscopy, staining, computed tomography scanning, and scanning electron microscopy-energy-dispersive spectrometry. We quantified the extreme bending capacity of single teeth (up to 180°) and show that reorganizations of the tooth (micro)structure and extreme hypomineralization of the dentin are adaptations preventing breaking by allowing flexibility. Tooth shape and internal structure appear to be optimized for bending in one direction, which is expected to occur frequently when feeding (scraping) under natural conditions. Not all loricariid catfishes possess flexible teeth, with the trait potentially having evolved more than once. Flexible teeth surely rank among the most extreme evolutionary novelties in known mineralized biological materials and might yield a better understanding of the processes of dentin formation and (hypo)mineralization in vertebrates, including humans.

  3. Rapid Sunspot Displacement Associated with Solar Eruptions

    NASA Astrophysics Data System (ADS)

    Liu, Chang; Deng, N.; Wang, H.

    2010-05-01

    Many observational and modeling studies of solar eruptions merely treat photosphere as the lower boundary and assume no significant changes of magnetic fields anchoring there to occur during flares/CMEs. With increasing evidence of photospheric magnetic fields variations resulting from energy release in the upper atmosphere, Hudson, Fisher and Welsch (2008, ASP, 383, 221) proposed that the photosphere and even solar interior would respond in a back-reaction process to the coronal magnetic field restructuring. Inspired by this concept, we analyzed white-light images obtained with TRACE and report here rapid and permanent perturbation in the position of delta spot umbrae associated with five X-class flares. Our main results are the following: (1) The centroids of umbrae with opposite magnetic polarities undergo relative as well as overall displacement on the order of 1E3 km after flares/CMEs. (2) The estimated total kinetic energy associated with these motions (Ek) is on the order of 1E29 ergs and appears to correlate with the 6 mHZ seismic energy (Es) derived by the Monash group. (3) There appears correlation between both the Ek and Es corresponding to the velocity of CMEs. We suggest that: (1) sunspot displacement provides a direct observational evidence of the photospheric back-reaction and could potentially serve as an alternative excitation mechanism of seismic waves; (2) These could provide rational support to the back-reaction mechanism in the sense that its magnitude might be related to how violent the coronal magnetic field is disrupted. For selected events with good multiwavelength coverage, we also analyze in detail spatial as well as temporal relationship among the sunspot displacement, magnetic field changes, seismic sources, hard X-ray emissions, and overall flaring condition. This work is supported by NSF grants ATM 08-19662 and ATM 07-45744, and NASA grants NNX 08AQ90G, NNX 07AH78G, and NNX 08AQ32G.

  4. Precursors of eruptions at Vesuvius (Italy)

    NASA Astrophysics Data System (ADS)

    Scandone, Roberto; Giacomelli, Lisetta

    2008-04-01

    The historical record of activity of Mount Vesuvius is uncommonly long and may serve as a guide to understand precursors before the outbreak of new activity. Reposes of different lengths have been observed in the past, with long ones preceding violent explosive eruptions. Eruptions occurring during periods of permanent activity have been preceded by possible deformation of the volcanic edifice and by short duration, earthquake swarms. Otherwise they have occurred without any reported precursors. The renewal of activity after long periods, like the current one, has been preceded by unrest lasting years to weeks, as a new eruption would require connection to the surface of a reservoir at depth ranging between 6 and 4 km. Since 1944, episodic seismic swarms, have occurred with a frequency similar to that of the violent strombolian eruptions during the last period of permanent activity; they are interpreted as intrusions and arrest of magma batches into a reservoir at the same depth of that feeding past sub-plinian eruptions.

  5. 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.

  6. An arcade-like eruptive prominence

    NASA Astrophysics Data System (ADS)

    Zhong, Shu-Hua; Zhan, La-Sheng

    2004-12-01

    An eruptive prominence happened on the east-northern limb of the Sun on March 7, 1991. It appeared in a relatively quiet region where any activity phenomena such as flare, filament and sunspot etc. was not found. The maximum height reachable of the prominence was 6.97×104km and its maximum length reached as 11.6×104km. The eruptive prominence might belong to the one of the middle-smaller scale according to its size in morphology. The course of the eruption exhibited some properties: ascending rapidly and descending slowly just like the process of the flare eruption. After the eruption, the most material in the prominence basically moved along a parabola under the action of magnetic force lines forming the arcade-like shape and keeping it till to the disappearance of the prominence. Before and after descending, a little matter came from the top part was ejected and divorced from the main body of the prominence and diffused into the interplanetary space.

  7. Coronal Bright Points Associated with Minifilament Eruptions

    NASA Astrophysics Data System (ADS)

    Hong, Junchao; Jiang, Yunchun; Yang, Jiayan; Bi, Yi; Li, Haidong; Yang, Bo; Yang, Dan

    2014-12-01

    Coronal bright points (CBPs) are small-scale, long-lived coronal brightenings that always correspond to photospheric network magnetic features of opposite polarity. In this paper, we subjectively adopt 30 CBPs in a coronal hole to study their eruptive behavior using data from the Atmospheric Imaging Assembly (AIA) and the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory. About one-quarter to one-third of the CBPs in the coronal hole go through one or more minifilament eruption(s) (MFE(s)) throughout their lifetimes. The MFEs occur in temporal association with the brightness maxima of CBPs and possibly result from the convergence and cancellation of underlying magnetic dipoles. Two examples of CBPs with MFEs are analyzed in detail, where minifilaments appear as dark features of a cool channel that divide the CBPs along the neutral lines of the dipoles beneath. The MFEs show the typical rising movements of filaments and mass ejections with brightenings at CBPs, similar to large-scale filament eruptions. Via differential emission measure analysis, it is found that CBPs are heated dramatically by their MFEs and the ejected plasmas in the MFEs have average temperatures close to the pre-eruption BP plasmas and electron densities typically near 109 cm-3. These new observational results indicate that CBPs are more complex in dynamical evolution and magnetic structure than previously thought.

  8. Coronal bright points associated with minifilament eruptions

    SciTech Connect

    Hong, Junchao; Jiang, Yunchun; Yang, Jiayan; Bi, Yi; Li, Haidong; Yang, Bo; Yang, Dan

    2014-12-01

    Coronal bright points (CBPs) are small-scale, long-lived coronal brightenings that always correspond to photospheric network magnetic features of opposite polarity. In this paper, we subjectively adopt 30 CBPs in a coronal hole to study their eruptive behavior using data from the Atmospheric Imaging Assembly (AIA) and the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory. About one-quarter to one-third of the CBPs in the coronal hole go through one or more minifilament eruption(s) (MFE(s)) throughout their lifetimes. The MFEs occur in temporal association with the brightness maxima of CBPs and possibly result from the convergence and cancellation of underlying magnetic dipoles. Two examples of CBPs with MFEs are analyzed in detail, where minifilaments appear as dark features of a cool channel that divide the CBPs along the neutral lines of the dipoles beneath. The MFEs show the typical rising movements of filaments and mass ejections with brightenings at CBPs, similar to large-scale filament eruptions. Via differential emission measure analysis, it is found that CBPs are heated dramatically by their MFEs and the ejected plasmas in the MFEs have average temperatures close to the pre-eruption BP plasmas and electron densities typically near 10{sup 9} cm{sup –3}. These new observational results indicate that CBPs are more complex in dynamical evolution and magnetic structure than previously thought.

  9. 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

  10. Changing concepts of decorum and allure in the representation of teeth in art.

    PubMed

    Trumble, A

    1998-10-01

    During the twentieth century western attitudes towards facial beauty have been transformed by developments in modern dental science. The possibility not only of retaining one's own teeth in adulthood, but also improving their appearance, changing the position, shape and colour, altering the contours of the face, eliminating deformity through different kinds of surgery--all of these astonishing developments have brought about a fundamental change in the way we see the human face, and how we expect it to look back at us. This paper illustrates the extent of the transformation of western attitudes towards facial beauty in the twentieth century by examining the ways artists have represented or, more frequently, concealed teeth in European painting and sculpture at key points since the sixteenth century. It examines some traditional prejudices (which still flourished in Victorian Britain, for example) against the open display of teeth, long regarded as threatening, indecent, at times lurid, rarely beautiful. It explores the widespread belief that rotten teeth were synonymous with moral corruption. It assesses the impact of modern media upon recent and quite radically different canons of beauty--the twentieth-century emphasis upon facial symmetry, for example, a concept foreign to the European portrait tradition--and concludes by examining a unique collaboration between artists, patients and maxillofacial surgeons currently taking place in the Cleft Palate Unit at Guy's Hospital in London, a project organized by the Ruskin School of Drawing at Oxford University.

  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. Source Inversions of Volcano Infrasound: Mass Outflux and Force System for Transient Explosive Eruptions

    NASA Astrophysics Data System (ADS)

    Kim, K.; Fee, D.; Lees, J. M.; Yokoo, A.; Ruiz, M. C.

    2014-12-01

    Sources of volcano infrasound associated with explosive eruptions are typically modeled assuming an acoustic monopole and/or dipole. While the monopole represents the mass outflux of erupted materials, the dipole represents a force system acting in the source region during eruptions. Therefore, appropriate acoustic source inversions of volcano infrasound data can provide estimates of eruption parameters which are critical to understanding eruption dynamics. Reliability of the source parameters is dominantly controlled by the accuracy of the acoustic Green's functions between the source and receiver positions. Conventional source inversions of volcano infrasound, however, were typically performed using a simplified Green's function obtained in a free space or half space. This may result in intolerable errors in the source parameters, especially when the infrasound waveforms are significantly distorted by volcano topography and/or local atmospheric variability (i.e., layered velocity structure or wind). In this study we present a full waveform inversion technique for volcano infrasound using numerical Green's functions. A full 3-D Finite-Difference Time-Domain (FDTD) method accelerated with GPU is used to compute accurate Green's functions taking into account volcano topography and local atmospheric conditions. The presented method is applied to data recorded at Sakurajima volcano (Japan) and Tungurahua volcano (Ecuador), which provide a large volume of high-quality data recorded by azimuthally well-distributed stations within 2 -- 6 km distance of the volcanoes. We analyze infrasound signals associated with explosive eruptions exhibiting 1) distinct explosion waveforms followed by gas discharges and 2) strong anisotropic radiation patterns, which can be caused by either source directivity or topographic barriers/reflections. Here the role of topography in controlling the infrasound radiation is investigated through numerical modeling, and then the observed

  13. 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.

  14. Mafic intrusions triggering eruptions in Iceland

    NASA Astrophysics Data System (ADS)

    Sigmarsson, O.

    2012-04-01

    The last two eruptions in Iceland, Eyjafjallajökull 2010 and Grímsvötn 2011, were both provoked by an intrusion of more mafic magma into pre-existing magmatic system. Injection into the latter volcano, which is located in the main rift-zone of the island, above the presumed centre of the mantle plume and is the most active volcano of Iceland, has been gradual since the last eruption in 2004. In contrast, at Eyjafjallajökull volcano, one of the least active volcano in Iceland and located at the southern part of a propagating rift-zone where extensional tectonics are poorly developed, mafic magma intrusion occurred over less than a year. Beneath Eyjafjallajökull, a silicic intrusion at approximately 6 km depth was recharged with mantle derived alkali basalt that was injected into residual rhyolite from the penultimate eruption in the years 1821-23. The resulting magma mingIing process was highly complex, but careful sampling of tephra during the entire eruption allows the dynamics of the mingling process to be unravelled. Short-lived disequilibria between the gaseous nuclide 210Po and the much less volatile nuclide 210Pb, suggest that basalt accumulated beneath the silicic intrusion over approximately 100 days, or from early January 2010 until the onset of the explosive summit eruption on 14 April. Due to the degassing, crystal fractionation modified the composition of the injected mafic magma producing evolved Fe-and Ti-rich basalt, similar in composition to that of the nearby Katla volcano. This evolved basalt was intruded into the liquid part of the silicic intrusion only a few hours before the onset of the explosive summit eruption. The short time between intrusion and eruption led to the production of very heterogeneous (of basaltic, intermediate and silicic composition) and fine-grained tephra during the first days of explosive eruption. The fine grained tephra resulted from combined effects of magma fragmentation due to degassing of stiff magma rich in

  15. 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.

  16. Magnetic Reconnection in a Solar Eruption -Formation of the Flux Tube and its Eruption-

    NASA Astrophysics Data System (ADS)

    Inoue, Satoshi; Büchner, Jörg

    2016-07-01

    A solar eruption is one of a dramatic phenomenon observed in the solar corona. The flux tube, which is a bundle of highly twisted lines, is widely believed as a driver source of the eruption. Although the magnetic reconnection is a key process of the formation of the flux tube as well as the eruptive process, these dynamics are still open to be solved. In order to clarify these dynamics, we first perform a magnetohydrodynamic (MHD) simulation using a force-free field extrapolated from the photospheric magnetic field. Our simulation successfully produced the typical eruptive processes in which the twisted flux tube slowly ascends in the beginning of the eruption; afterwards, it shows the fast ascending. We found that the reconnection is a key process to break the force-free field initially constructed, and highly twisted flux tube formation during the slow rising phase and even after the fast eruption. Next we compare with Büchner + Skala simulations and compressively discuss the play of the reconnection in the solar eruption.

  17. 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.

  18. 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.