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Sample records for dental amalgam fillings

  1. Dental Amalgam

    MedlinePlus

    ... Products and Medical Procedures Dental Devices Dental Amalgam Dental Amalgam Share Tweet Linkedin Pin it More sharing options Linkedin Pin it Email Print Dental amalgam is a dental filling material which is ...

  2. Aggravated neuromuscular symptoms of mercury exposure from dental amalgam fillings.

    PubMed

    Akbal, Ayla; Yılmaz, Hınç; Tutkun, Engin; Köş, Durdu Mehmet

    2014-01-01

    Dental amalgam fillings are widely used all over the world. However, their mercury content can lead to various side effects and clinical problems. Acute or chronic mercury exposure can cause several side effects on the central nerve system, renal and hepatic functions, immune system, fetal development and it can play a role on exacerbation of neuromuscular diseases. In this case, we will present a patient with vacuolar myopathy whose symptoms were started and aggravated with her dental amalgam fillings.

  3. Mercury Exposure Levels in Children with Dental Amalgam Fillings

    PubMed Central

    Miriam Varkey, Indu; Shetty, Rajmohan; Hegde, Amitha

    2014-01-01

    ABSTRACT% Objectives: Mercury combined with other metals to form solid amalgams has long been used in reconstructive dentistry but its use has been controversial since at least the middle of the 19th century. The exposure and body burden of mercury reviews have consistently stated that there is a deficiency of adequate epidemiological studies addressing this issue. Fish and dental amalgam are two major sources of human exposure to organic (MeHg) and inorganic Hg respectively. Materials and methods: A total of 150 subjects aged between 9 and 14 years were divided into two groups of 75 subjects each depending on their diet, i.e. seafood or nonseafood consuming. Each category was subdivided into three groups based on number of restorations. Scalp hair and urine samples were collected at baseline and 3 months later to assess the organic and inorganic levels of mercury respectively by atomic absorption spectrophotometer (AAS). Results: The mean values of urinary mercury (inorganic mercury) in the group of children with restorations were 1.5915 μg/l as compared to 0.0130 μg/l in the groups with no amalgam restorations (p < 0.001) (Wilcoxon sign rank test and paired t-test). The hair mercury levels (organic mercury) varied signi-ficantly between the fsh-eating group and nonfsh-eating group, the average values being 1.03 μg/l and 0.84 μg/l respectively (p < 0.001) (Mann-Whitney U-test and paired t-test). Conclusion and significance: The notion about the mercury being released from the amalgam restorations as a sole exposure source needs to be put to a rest, as environmental factors collectively overpower the exposure levels from restorations alone. How to cite this article: Varkey IM, Shetty R, Hegde A. Mercury Exposure Levels in Children with Dental Amalgam Fillings. Int J Clin Pediatr Dent 2014;7(3):180-185. PMID:25709298

  4. Maternal-fetal distribution of mercury ( sup 203 Hg) released from dental amalgam fillings

    SciTech Connect

    Vimy, M.J.; Takahashi, Y.; Lorscheider, F.L. )

    1990-04-01

    In humans, the continuous release of Hg vapor from dental amalgam tooth restorations is markedly increased for prolonged periods after chewing. The present study establishes a time-course distribution for amalgam Hg in body tissues of adult and fetal sheep. Under general anesthesia, five pregnant ewes had twelve occlusal amalgam fillings containing radioactive 203Hg placed in teeth at 112 days gestation. Blood, amniotic fluid, feces, and urine specimens were collected at 1- to 3-day intervals for 16 days. From days 16-140 after amalgam placement (16-41 days for fetal lambs), tissue specimens were analyzed for radioactivity, and total Hg concentrations were calculated. Results demonstrate that Hg from dental amalgam will appear in maternal and fetal blood and amniotic fluid within 2 days after placement of amalgam tooth restorations. Excretion of some of this Hg will also commence within 2 days. All tissues examined displayed Hg accumulation. Highest concentrations of Hg from amalgam in the adult occurred in kidney and liver, whereas in the fetus the highest amalgam Hg concentrations appeared in liver and pituitary gland. The placenta progressively concentrated Hg as gestation advanced to term, and milk concentration of amalgam Hg postpartum provides a potential source of Hg exposure to the newborn. It is concluded that accumulation of amalgam Hg progresses in maternal and fetal tissues to a steady state with advancing gestation and is maintained. Dental amalgam usage as a tooth restorative material in pregnant women and children should be reconsidered.

  5. High-field MRI and mercury release from dental amalgam fillings.

    PubMed

    Mortazavi, S M J; Neghab, M; Anoosheh, S M H; Bahaeddini, N; Mortazavi, G; Neghab, P; Rajaeifard, A

    2014-04-01

    Mercury is among the most toxic nonradioactive elements which may cause toxicity even at low doses. Some studies showed release of mercury from dental amalgam fillings in individuals who used mobile phone. This study was conducted to assess the effect of high-field MRI on mercury release from dental amalgam filling. We studied two groups of students with identical tooth decays requiring a similar pattern of restorative dentistry. They were exposed to a magnetic flux density of 1.5 T produced by a MRI machine. 16 otherwise healthy students with identical dental decay participated in this study. They underwent similar restorative dentistry procedures and randomly divided into two groups of MRI-exposed and control arms. Urinary concentrations of mercury in the control subjects were measured before (hour 0) and 48 and 72 hrs after amalgam restoration, using cold vapor atomic absorption spectrometry. Urinary concentrations of mercury in exposed individuals were determined before (hour 0), and 24, 48, 72 and 96 hrs after amalgam restoration. Unlike control subjects, they underwent conventional brain MRI (15 min, 99 slices), 24 hrs after amalgam restoration. The mean±SD urinary mercury levels in MRI-exposed individuals increased linearly from a baseline value of 20.70±17.96 to 24.83±22.91 μg/L 72 hrs after MRI. In the control group, the concentration decreased linearly from 20.70±19.77 to 16.14±20.05 μg/L. The difference between urinary mercury in the exposed and control group, 72 hrs after MRI (96 h after restoration),was significant (p=0.046). These findings provide further support for the noxious effect of MRI (exposure to strong magnetic field)and release of mercury from dental amalgam fillings.

  6. Effect of mercury (Hg) dental amalgam fillings on renal and oxidative stress biomarkers in children.

    PubMed

    Al-Saleh, Iman; Al-Sedairi, Al anoud; Elkhatib, Rola

    2012-08-01

    We examined the effect of mercury (Hg) associated with dental amalgam fillings on biomarkers of renal and oxidative stress in children between the ages of 5-15.5 years. Urine samples were analyzed for N-acetyl-β-D-glucosaminidase (NAG), α(1)-microglobulin (α(1)-MG), β(2)-microglobulin (β(2)-MG), retinol binding protein (RBP), albumin (ALB), 8-hydroxy-2-deoxyguanosine (8-OHdG) and malondialdehyde (MDA). The level of urinary Hg (UHg-C) was calculated as μg/g creatinine. Multiple regression analyses revealed that the excretion of urinary NAG was significantly associated with the presence of dental amalgam fillings (β=0.149, P=0.03) and the levels of UHg-C (β=0.531, P=0), with an interaction between the two (P=0). The increase in urinary NAG in relation to UHg-C levels had a dose-effect pattern. The lowest observed effect was seen at UHg-C levels above 1.452 μg/g creatinine, which is lower than previously reported. In contrast, α(1)-MG was negatively associated with the presence of dental amalgam fillings (β=-0.270, P=0), but positively with UHg-C levels (β=0.393, P=0). There were 7 children without, and one child with, dental amalgam fillings with urinary α(1)-MG levels above the reference limit of >7 mg/g creatinine. Even though α(1)-MG seems to be a reliable biomarker for early changes in renal functions, it might exert its effect only at a higher level of exposure. An inverse relationship was also observed between urinary 8-OHdG levels and the presence of dental amalgam fillings. This might suggest that the dental amalgam does not increase DNA damage but reduces the capacity to repair DNA, leading to lower urinary excretion of 8-OHdG. On the other hand, we found that Hg affected the excretion of urinary 8-OHdG in a dose-related pattern that was mostly associated with long-term exposure to low Hg levels. Urinary NAG levels were positively associated with urinary MDA levels (β=0.516, P=0) but not with 8-OHdG (β=0.134, P=0.078) after adjustment for

  7. Dental amalgam and mercury

    SciTech Connect

    Mackert, J.R. Jr. )

    1991-08-01

    This paper looks at the issues of the current amalgam controversy: the daily dose of mercury from amalgam, hypersensitivity to mercury, claims of adverse effects from amalgam mercury and alleged overnight 'cures.' In addition, the toxicity and allergenicity of the proposed alternative materials are examined with the same kind of scrutiny applied by the anti-amalgam group to dental amalgam. 100 references.

  8. Dental amalgam: An update

    PubMed Central

    Bharti, Ramesh; Wadhwani, Kulvinder Kaur; Tikku, Aseem Prakash; Chandra, Anil

    2010-01-01

    Dental amalgam has served as an excellent and versatile restorative material for many years, despite periods of controversy. The authors review its history, summarize the evidence with regard to its performance and offer predictions for the future of this material. The PubMed database was used initially; the reference list for dental amalgam featured 8641 articles and 13 publications dealing with recent advances in dental amalgam. A forward search was undertaken on selected articles and using some author names. For the present, amalgam should remain the material of choice for economic direct restoration of posterior teeth. When esthetic concerns are paramount, tooth-colored materials, placed meticulously, can provide an acceptable alternative. All alternative restorative materials and procedures, however, have certain limitations. PMID:21217947

  9. Dental amalgam--environmental aspects

    SciTech Connect

    Arenholt-Bindslev, D. )

    1992-09-01

    Increasing knowledge about the risk of toxic effects caused by anthropogenic mercury accumulation in ecosystems has resulted in a growing pressure for reduction of the discharge of mercury waste. Consequently, the mercury waste problems of dental clinics have been given increased attention, and restrictions on handling and discharge of contaminated waste have been established in several countries. Major amalgam particles from trituration surplus of those produced during the carving and burnishing of new amalgam restorations are generally collected in coarse filters and sold for refinement. Minor amalgam particles released by production of new fillings or by removal of old restorations partly sediment in tubes and drains. The remaining particles are carried with the waste water stream to the local purifying plant. In Scandinavia, the industrial discharge of mercury-contaminated waste water has been reduced to a minimum. According to recent investigations, dental clinics appear to be responsible for the major amount of mercury collected in the sludge generated in purifying plants. If threshold values for heavy metal content, including mercury, are exceeded, the sludge is not allowed to be recycled as fertilizer. Installation of an approved amalgam-separating apparatus in dental clinics is now mandatory in several countries--for example, Switzerland, Germany, Sweden, and Denmark. Approval of amalgam separators is based on national testing programs, including clinical or laboratory tests demanding 95-99% separating efficiency. 18 refs.

  10. Mercury exposure from dental amalgam fillings: absorbed dose and the potential for adverse health effects.

    PubMed

    Mackert, J R; Berglund, A

    1997-01-01

    This review examines the question of whether adverse health effects are attributable to amalgam-derived mercury. The issue of absorbed dose of mercury from amalgam is addressed first. The use of intra-oral Hg vapor measurements to estimate daily uptake must take into account the differences between the collection volume and flow rate of the measuring instrument and the inspiratory volume and flow rate of air through the mouth during inhalation of a single breath. Failure to account for these differences will result in substantial overestimation of the absorbed dose. Other factors that must be considered when making estimates of Hg uptake from amalgam include the accurate measurement of baseline (unstimulated) mercury release rates and the greater stimulation of Hg release afforded by chewing gum relative to ordinary food. The measured levels of amalgam-derived mercury in brain, blood, and urine are shown to be consistent with low absorbed doses (1-3 micrograms/day). Published relationships between the number of amalgam surfaces and urine levels are used to estimate the number of amalgam surfaces that would be required to produce the 30 micrograms/g creatinine urine mercury level stated by WHO to be associated with the most subtle, pre-clinical effects in the most sensitive individuals. From 450 to 530 amalgam surfaces would be required to produce the 30 micrograms/g creatinine urine mercury level for people without any excessive gum-chewing habits. The potential for adverse health effects and for improvement in health following amalgam removal is also addressed. Finally, the issue of whether any material can ever be completely exonerated of claims of producing adverse health effects is considered.

  11. 21 CFR 872.3100 - Dental amalgamator.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... and dental alloy particles, such as silver, tin, zinc, and copper. The mixed dental amalgam material... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Dental amalgamator. 872.3100 Section 872.3100 Food... DEVICES DENTAL DEVICES Prosthetic Devices § 872.3100 Dental amalgamator. (a) Identification. A...

  12. 21 CFR 872.3100 - Dental amalgamator.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... and dental alloy particles, such as silver, tin, zinc, and copper. The mixed dental amalgam material... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Dental amalgamator. 872.3100 Section 872.3100 Food... DEVICES DENTAL DEVICES Prosthetic Devices § 872.3100 Dental amalgamator. (a) Identification. A...

  13. 21 CFR 872.3100 - Dental amalgamator.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... and dental alloy particles, such as silver, tin, zinc, and copper. The mixed dental amalgam material... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Dental amalgamator. 872.3100 Section 872.3100 Food... DEVICES DENTAL DEVICES Prosthetic Devices § 872.3100 Dental amalgamator. (a) Identification. A...

  14. Mercury toxicity and dental amalgam

    SciTech Connect

    Wolff, M.; Osborne, J.W.; Hanson, A.L.

    1982-01-01

    There is adequate evidence that dental amalgam restorations, during and after placement, results in the release of Hg into the patients's body. Whether the Hg released from amalgam is due to placement procedures, surface abrasion, or later corrosion breakdown, there is evidence that a low level Hg release continues for years. With new and more accurate techniques of measuring Hg levels, especially in tissue and blood, additional studies are necessary to relate blood-Hg levels with dental amalgam restorations. Studies must relate existing restorations as well as the placement of new restorations to body-Hg levels. It is possible that we have accepted a potentially dangerous material as being safe.

  15. Human brain mercury levels related to exposure to amalgam fillings.

    PubMed

    Ertaş, E; Aksoy, A; Turla, A; Karaarslan, E S; Karaarslan, B; Aydın, A; Eken, A

    2014-08-01

    The safety of dental amalgam as the primary material in dental restoration treatments has been debated since its introduction. It is widely accepted that amalgam restorations continuously release elemental mercury (Hg) vapor, which is inhaled and absorbed by the body and distributed to tissues, including the brain. The aim of the present study was to investigate whether the presence of amalgam fillings is correlated with brain Hg level. The Hg levels in the parietal lobes of the brains of 32 cadavers were analyzed with an atomic absorption spectrometer with the mercury hydride system. A total of 32 brain samples were tested; of these, 10 were from cadavers with amalgam fillings, while 22 of them were amalgam free. Hg was detected in 60.0% (6 of 10) of the samples in the amalgam group and in 36.3% (8 of 22) in the amalgam-free group. The average Hg level of the amalgam group was 0.97 ± 0.83 µg/g (minimum: 0.3 µg/g and maximum: 2.34 µg/g), and in the amalgam-free group, it was 1.06 ± 0.57 µg/g (minimum: 0.17 µg/g and maximum: 1.76 µg/g). The results of the present study showed no correlation between the presence of amalgam fillings and brain Hg level.

  16. Tensile creep of dental amalgam.

    PubMed

    Greener, E H; Szurgot, K; Lautenschlager, E P

    1982-04-01

    Rather than the usual compressive dental creep, various types of one week old dental amalgams were continuously monitored in tensile creep. Testing was done at 37, 45 and 50 degrees C, in a specially designed apparatus capable of 0 to 60 degrees C while maintaining a constant true tensile stress of 17 MPa. For the first time, the classical four stages of creep were observed at elevated temperatures in the low Cu amalgams, including creep rupture. The high Cu systems displayed only transient creep up to 50 degrees C and no rupture. Approximately one half the stress was needed in tension to provide the equivalent creep in compression. PMID:7082735

  17. [Experience with amalgams manufactured by Southern Dental Industries (Australia)].

    PubMed

    Tarján, I; Gábris, K; Balaton, P; Dénes, J

    1990-09-01

    The gamma 2 phaseless amalgam of the firm Southern Dental Industries (SDI) was tested. None of the 205 fillings showed level deviations, unevenness, secondary caries and breakage. A minimum size gap was found in 2 cases.

  18. Dental amalgam, mercury toxicity, and renal autoimmunity.

    PubMed

    Guzzi, Gianpaolo; Fogazzi, Giovanni Battista; Cantù, Mariadele; Minoia, Claudio; Ronchi, Anna; Pigatto, Paolo D; Severi, Gianluca

    2008-01-01

    Chronic exposure to elemental metallic mercury may induce an immunological glomerular disease. Since humans are exposed to mercury vapor (Hg0) from dental amalgam restorations and kidney is an important target organ of mercury vapor and mercury deposition in kidney increases proportionally with the dose, our aim was to test the occurrence of specific antibodies to antiglomerular basement membrane (anti-GBM-IgG) among individuals with adverse effects to mercury from dental amalgam fillings. We selected a group of patients (n=24) with a history of long-term exposure to mercury vapor from mercury-containing amalgam fillings and showing adverse effects that were laboratory confirmed. Enzyme-linked immunosorbent assays (ELISAs) were used to evaluate serum levels of antibodies to anti-GBM-IgG. None of the patients showed evidence of anti-GBM autoimmunity, either in subgroups with strong allergy to mercury or its compounds (i.e., organic mercury) or in those patients who had past thimerosal-containing vaccines coverage (7 of 24). There was no evidence of the presence of circulating anti-GBM antibodies in subjects suffering from adverse events due to long-term exposure to mercury from dental amalgams, even in individuals who presented allergy to mercury.

  19. About Dental Amalgam Fillings

    MedlinePlus

    ... same as the mercury in some types of fish? No. There are several different chemical forms of ... mercury vapor. The form of mercury found in fish is methylmercury, a type of organic mercury. Mercury ...

  20. Increased Zn/Glutathione Levels and Higher Superoxide Dismutase-1 Activity as Biomarkers of Oxidative Stress in Women with Long-Term Dental Amalgam Fillings: Correlation between Mercury/Aluminium Levels (in Hair) and Antioxidant Systems in Plasma

    PubMed Central

    Cabaña-Muñoz, María Eugenia; Parmigiani-Izquierdo, José María; Bravo-González, Luis Alberto; Kyung, Hee-Moon; Merino, José Joaquín

    2015-01-01

    Background The induction of oxidative stress by Hg can affect antioxidant enzymes. However, epidemiological studies have failed to establish clear association between dental fillings presence and health problems. Objectives To determine whether heavy metals (in hair), antioxidant enzymes (SOD-1) and glutathione levels could be affected by the chronic presence of heavy metals in women who had dental amalgam fillings. Materials and Methods 55 hair samples (42 females with amalgam fillings and 13 female control subjects) were obtained. All subjects (mean age 44 years) who had dental amalgam filling for more than 10 years (average 15 years). Certain metals were quantified by ICP-MS (Mass Spectrophotometry) in hair (μg/g: Al, Hg, Ba, Ag, Sb, As, Be, Bi, Cd, Pb, Pt, Tl, Th, U, Ni, Sn, Ti) and SOD-1 and Glutathione (reduced form) levels in plasma. Data were compared with controls without amalgams, and analyzed to identify any significant relation between metals and the total number of amalgam fillings, comparing those with four or less (n = 27) with those with more than four (n = 15). As no significant differences were detected, the two groups were pooled (Amlgam; n = 42). Findings Hg, Ag, Al and Ba were higher in the amalgam group but without significant differences for most of the heavy metals analyzed. Increased SOD-1 activity and glutathione levels (reduced form) were observed in the amalgam group. Aluminum (Al) correlated with glutathione levels while Hg levels correlated with SOD-1. The observed Al/glutathione and Hg/SOD-1 correlation could be adaptive responses against the chronic presence of mercury. Conclusions Hg, Ag, Al and Ba levels increased in women who had dental amalgam fillings for long periods. Al correlated with glutathione, and Hg with SOD-1. SOD-1 may be a possible biomarker for assessing chronic Hg toxicity. PMID:26076368

  1. 21 CFR 872.3100 - Dental amalgamator.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Dental amalgamator. 872.3100 Section 872.3100 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3100 Dental amalgamator. (a) Identification. A...

  2. 21 CFR 872.3100 - Dental amalgamator.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Dental amalgamator. 872.3100 Section 872.3100 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3100 Dental amalgamator. (a) Identification. A...

  3. Critical appraisal: dental amalgam update--part II: biological effects.

    PubMed

    Wahl, Michael J; Swift, Edward J

    2013-12-01

    Dental amalgam restorations have been controversial for over 150 years. In Part I of this Critical Appraisal, the clinical efficacy of dental amalgam was updated. Here in Part II, the biological effects of dental amalgam are addressed.

  4. A dose-dependent relationship between mercury exposure from dental amalgams and urinary mercury levels: a further assessment of the Casa Pia Children's Dental Amalgam Trial.

    PubMed

    Geier, D A; Carmody, T; Kern, J K; King, P G; Geier, Mark R

    2012-01-01

    Dental amalgams are a commonly used dental restorative material, and amalgams are about 50% mercury (Hg). In our study, urinary Hg levels was examined in children of age 8-18 years, with and without dental amalgam fillings, from a completed clinical trial (parent study) that was designed to evaluate the potential health consequences of prolonged exposure to Hg from dental amalgam fillings. Our study was designed to determine whether there was a significant dose-dependent correlation between increasing Hg exposure from dental amalgams and urinary Hg levels. Hg exposure depends on the size and number of teeth with dental amalgams. Overall, consistent with the results observed in the parent study, there was a statistically significant dose-dependent correlation between cumulative exposure to Hg from dental amalgams and urinary Hg levels, after covariate adjustment. Further, it was observed that urinary Hg levels increased by 18% to 52% among 8 to 18 year old individuals, respectively, with an average exposure to amalgams, in comparison to study subjects with no exposure to amalgams. The results of our study suggest that dental amalgams contribute to ongoing Hg exposure in a dose-dependent fashion.

  5. Mercury (Hg) burden in children: the impact of dental amalgam.

    PubMed

    Al-Saleh, Iman; Al-Sedairi, Al Anoud

    2011-07-15

    The risks and benefits of using mercury (Hg) in dental amalgam have long been debated. This study was designed to estimate Hg body burden and its association with dental amalgam fillings in 182 children (ages: 5-15 years) living in Taif City. Hg was measured in urine (UHg), hair (HHg) and toenails (NHg) by the Atomic Absorption Spectrophotometer with Vapor Generator Accessory system. Urinary Hg levels were calculated as both micrograms per gram creatinine (μg/g creatinine) and micrograms per liter (μg/L). We found that children with amalgam fillings (N=106) had significantly higher UHg-C levels than children without (N=76), with means of 3.763 μg/g creatinine versus 3.457 μg/g creatinine, respectively (P=0.019). The results were similar for UHg (P=0.01). A similar pattern was also seen for HHg, with means of 0.614 μg/g (N=97) for children with amalgam versus 0.242 μg/g (N=74) for those without amalgam fillings (P=0). Although the mean NHg was higher in children without amalgam (0.222 μg/g, N=61) versus those with (0.163 μg/g, N=101), the relationship was not significant (P=0.069). After adjusting for many confounders, the multiple logistic regression model revealed that the levels of UHg-C and HHg were 2.047 and 5.396 times higher, respectively, in children with dental amalgam compared to those without (P<0.01). In contrast, a significant inverse relationship was seen between NHg levels and dental amalgam fillings (P=0.003). Despite the controversy surrounding the health impact of dental amalgam, this study showed some evidence that amalgam-associated Hg exposure might be related with symptoms of oral health, such as aphthous ulcer, white patches, and a burning-mouth sensation. Further studies are needed to reproduce these findings. The present study showed that significant numbers of children with or without amalgam had Hg levels exceeding the acceptable reference limits. The detrimental neurobehavioral and/or nephrotoxic effects of such an increased Hg on

  6. High mercury emissions from dental clinics despite amalgam separators.

    PubMed

    Hylander, Lars D; Lindvall, Anders; Gahnberg, Lars

    2006-06-01

    Mercury (Hg) as amalgam has been used as a dental filling material for more than 150 years. Thereby, dentists and their patients have been directly exposed to Hg, and the public and the environment indirectly exposed via Hg emissions from incinerators and Hg in waste water from households and dental clinics. Due to the toxic properties of Hg and bioaccumulation in biota of Hg emitted via dental clinic waste water, amalgam separators were introduced in Sweden in the 1980s. Although these amalgam separators in the certification process are required to remove at least 95% of incoming Hg in a standardized laboratory test, their efficiency in practical use has not been properly investigated. Here we present actual Hg emissions via waste water from 12 dental clinics equipped with the same type of amalgam separator based on sedimentation. All waste water was collected for four consecutive working days, initially at ordinary operating conditions and a second time after a thorough revision and cleaning of the discharge system. The results indicate that mercury emissions from dental clinics can be reduced by an improved design of the discharge system, a sensible use of high pressure water cleaning, and regular maintenance, including replacement of amalgam separators and filters at certain intervals. The study also indicates that banning Hg in dentistry is the one long-term way to stop Hg emissions from dental amalgam.

  7. 21 CFR 872.3070 - Dental amalgam, mercury, and amalgam alloy.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Dental amalgam, mercury, and amalgam alloy. 872... SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3070 Dental amalgam, mercury... elemental mercury, supplied as a liquid in bulk, sachet, or predosed capsule form, and amalgam...

  8. 21 CFR 872.3070 - Dental amalgam, mercury, and amalgam alloy.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Dental amalgam, mercury, and amalgam alloy. 872... SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3070 Dental amalgam, mercury... elemental mercury, supplied as a liquid in bulk, sachet, or predosed capsule form, and amalgam...

  9. 21 CFR 872.3070 - Dental amalgam, mercury, and amalgam alloy.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Dental amalgam, mercury, and amalgam alloy. 872... SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3070 Dental amalgam, mercury... elemental mercury, supplied as a liquid in bulk, sachet, or predosed capsule form, and amalgam...

  10. 21 CFR 872.3070 - Dental amalgam, mercury, and amalgam alloy.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Dental amalgam, mercury, and amalgam alloy. 872... SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3070 Dental amalgam, mercury... elemental mercury, supplied as a liquid in bulk, sachet, or predosed capsule form, and amalgam...

  11. Dental Amalgam Exposure and Urinary Mercury Levels in Children: The New England Children’s Amalgam Trial

    PubMed Central

    Maserejian, Nancy Nairi; Trachtenberg, Felicia L.; Assmann, Susan F.; Barregard, Lars

    2008-01-01

    Background Urinary mercury (U-Hg) excretion is a commonly used biomarker for mercury exposure from dental amalgam restorations. Objectives Our goal was to determine the most efficient measure of dental amalgam exposure for use in analyses concerning U-Hg in children. Methods We analyzed time-sensitive longitudinal amalgam exposure data in children randomized to amalgam restorations (n = 267) during the 5-year New England Children’s Amalgam Trial. We calculated 8 measures of amalgam, evaluating current versus cumulative exposure, teeth versus surfaces, and total versus posterior occlusal amalgams. Urine samples collected during follow-up years 3–5 were analyzed for mercury excretion. Multivariate models for current and cumulative U-Hg excretion estimated associations between exposures and U-Hg. Results At the end of follow-up, the average (± SD) cumulative exposure was 10.3 ± 6.1 surfaces and 5.7 ± 2.9 teeth ever filled with amalgam, corresponding to 30 ± 21 surface-years. Amalgam measures and U-Hg were moderately correlated. Of amalgam exposure measures, the current total of amalgam surfaces was the most robust predictor of current U-Hg, whereas posterior occlusal surface-years was best for cumulative U-Hg. In multivariate models, each additional amalgam surface present was associated with a 9% increase in current U-Hg, and each additional posterior occlusal surface-year was associated with a 3% increase in cumulative U-Hg excretion (p < 0.001). Conclusions One single measure of amalgam exposure is insufficient. Studies of cumulative effects of mercury from amalgam exposure in children are likely to have improved validity and precision if time-sensitive amalgam exposure measures are used. In contrast, simple counts of current amalgam fillings are adequate to capture amalgam-related current U-Hg. PMID:18288327

  12. Dental amalgam: A review of the literature

    SciTech Connect

    Eggleston, D.W.

    1989-09-01

    Since the 1800s, dental amalgam has been the most commonly used dental restorative material. Each year, dentistry in the United States uses over 100 tons of mercury, continuing a controversy regarding mercury's safety for patients and dental personnel. 65 references.

  13. Mercury recovery in situ of four different dental amalgam separators.

    PubMed

    Hylander, Lars D; Lindvall, Anders; Uhrberg, Roland; Gahnberg, Lars; Lindh, Ulf

    2006-07-31

    Amalgam separators are used to physically remove dental amalgam from waste water in dental clinics. They are thereby supposed to reduce mercury (Hg) emissions to the municipal waste water system to acceptable levels. We here present results from a comparative study in situ of three amalgam separators available on the market, all with a claimed efficiency of 99% according to Danish and ISO protocols, and using sedimentation as the principle of separation. We also present corresponding data for an investigational prototype of an improved separator. The obtained efficiency of the three commercial separators is far below what is stated by the manufacturer and by authorities assumed to be the efficiency in clinical conditions. They reduced Hg emissions by 79 - 91%, leaving an average Hg content in outgoing waste water of 1.5 mg L(-1). However, the prototype separator participating in this study retained 99.9% of the waste water Hg emissions, leaving an average Hg content in outgoing waste water of 0.004 mg L(-1). Physical restrictions prohibit sedimentary type separators to recover the Hg fractions causing the largest damages in wastewater treatment plants. This fraction is not considered in the ISO protocol for testing amalgam separators, which therefore needs to be revised. Abolishing the use of dental amalgam and cleaning the tubing systems is the most efficient long-term solution to reduce Hg emissions from dental clinics. Until then, Hg emissions originating from placing, polishing or removing existing amalgam fillings, should be counteracted by the use of low-emission amalgam separators, already on the market or presently being developed for use alone or together with sedimentary type amalgam separators. PMID:16182343

  14. Increased Release of Mercury from Dental Amalgam Fillings due to Maternal Exposure to Electromagnetic Fields as a Possible Mechanism for the High Rates of Autism in the Offspring: Introducing a Hypothesis.

    PubMed

    Mortazavi, Gh; Haghani, M; Rastegarian, N; Zarei, S; Mortazavi, S M J

    2016-03-01

    According to the World Health Organization (WHO), factors such as growing electricity demand, ever-advancing technologies and changes in social behaviour have led to steadily increasing exposure to man-made electromagnetic fields.  Dental amalgam fillings are among the major sources of exposure to elemental mercury vapour in the general population. Although it was previously believed that low levels are mercury (i.g. release of mercury from dental amalgam) is not hazardous, now numerous data indicate that even very low doses of mercury cause toxicity. There are some evidence indicating that perinatal exposure to mercury is significantly associated with an increased risk of developmental disorders such as autism spectrum disorders (ASD) and attention-deficit hyperactivity disorder (ADHD). Furthermore, mercury can decrease the levels of neurotransmitters dopamine, serotonin, noreprenephrine, and acetylcholine in the brain and cause neurological problems. On the other hand, a strong positive correlation between maternal and cord blood mercury levels is found in some studies. We have previously shown that exposure to MRI or microwave radiation emitted by common mobile phones can lead to increased release of mercury from dental amalgam fillings. Moreover, when we investigated the effects of MRI machines with stronger magnetic fields, our previous findings were confirmed. As a strong association between exposure to electromagnetic fields and mercury level has been found in our previous studies, our findings can lead us to this conclusion that maternal exposure to electromagnetic fields in mothers with dental amalgam fillings may cause elevated levels of mercury and trigger the increase in autism rates. Further studies are needed to have a better understanding of the possible role of the increased mercury level after exposure to electromagnetic fields and the rate of autism spectrum disorders in the offspring.

  15. Increased Release of Mercury from Dental Amalgam Fillings due to Maternal Exposure to Electromagnetic Fields as a Possible Mechanism for the High Rates of Autism in the Offspring: Introducing a Hypothesis

    PubMed Central

    Mortazavi, Gh.; Haghani, M.; Rastegarian, N.; Zarei, S.; Mortazavi, S.M.J.

    2016-01-01

    According to the World Health Organization (WHO), factors such as growing electricity demand, ever-advancing technologies and changes in social behaviour have led to steadily increasing exposure to man-made electromagnetic fields.  Dental amalgam fillings are among the major sources of exposure to elemental mercury vapour in the general population. Although it was previously believed that low levels are mercury (i.g. release of mercury from dental amalgam) is not hazardous, now numerous data indicate that even very low doses of mercury cause toxicity. There are some evidence indicating that perinatal exposure to mercury is significantly associated with an increased risk of developmental disorders such as autism spectrum disorders (ASD) and attention-deficit hyperactivity disorder (ADHD). Furthermore, mercury can decrease the levels of neurotransmitters dopamine, serotonin, noreprenephrine, and acetylcholine in the brain and cause neurological problems. On the other hand, a strong positive correlation between maternal and cord blood mercury levels is found in some studies. We have previously shown that exposure to MRI or microwave radiation emitted by common mobile phones can lead to increased release of mercury from dental amalgam fillings. Moreover, when we investigated the effects of MRI machines with stronger magnetic fields, our previous findings were confirmed. As a strong association between exposure to electromagnetic fields and mercury level has been found in our previous studies, our findings can lead us to this conclusion that maternal exposure to electromagnetic fields in mothers with dental amalgam fillings may cause elevated levels of mercury and trigger the increase in autism rates. Further studies are needed to have a better understanding of the possible role of the increased mercury level after exposure to electromagnetic fields and the rate of autism spectrum disorders in the offspring. PMID:27026954

  16. Increased Release of Mercury from Dental Amalgam Fillings due to Maternal Exposure to Electromagnetic Fields as a Possible Mechanism for the High Rates of Autism in the Offspring: Introducing a Hypothesis.

    PubMed

    Mortazavi, Gh; Haghani, M; Rastegarian, N; Zarei, S; Mortazavi, S M J

    2016-03-01

    According to the World Health Organization (WHO), factors such as growing electricity demand, ever-advancing technologies and changes in social behaviour have led to steadily increasing exposure to man-made electromagnetic fields.  Dental amalgam fillings are among the major sources of exposure to elemental mercury vapour in the general population. Although it was previously believed that low levels are mercury (i.g. release of mercury from dental amalgam) is not hazardous, now numerous data indicate that even very low doses of mercury cause toxicity. There are some evidence indicating that perinatal exposure to mercury is significantly associated with an increased risk of developmental disorders such as autism spectrum disorders (ASD) and attention-deficit hyperactivity disorder (ADHD). Furthermore, mercury can decrease the levels of neurotransmitters dopamine, serotonin, noreprenephrine, and acetylcholine in the brain and cause neurological problems. On the other hand, a strong positive correlation between maternal and cord blood mercury levels is found in some studies. We have previously shown that exposure to MRI or microwave radiation emitted by common mobile phones can lead to increased release of mercury from dental amalgam fillings. Moreover, when we investigated the effects of MRI machines with stronger magnetic fields, our previous findings were confirmed. As a strong association between exposure to electromagnetic fields and mercury level has been found in our previous studies, our findings can lead us to this conclusion that maternal exposure to electromagnetic fields in mothers with dental amalgam fillings may cause elevated levels of mercury and trigger the increase in autism rates. Further studies are needed to have a better understanding of the possible role of the increased mercury level after exposure to electromagnetic fields and the rate of autism spectrum disorders in the offspring. PMID:27026954

  17. 21 CFR 872.3110 - Dental amalgam capsule.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Dental amalgam capsule. 872.3110 Section 872.3110...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3110 Dental amalgam capsule. (a) Identification. A dental amalgam capsule is a container device in which silver alloy is intended to be mixed with...

  18. 21 CFR 872.3110 - Dental amalgam capsule.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Dental amalgam capsule. 872.3110 Section 872.3110...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3110 Dental amalgam capsule. (a) Identification. A dental amalgam capsule is a container device in which silver alloy is intended to be mixed with...

  19. 21 CFR 872.3110 - Dental amalgam capsule.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Dental amalgam capsule. 872.3110 Section 872.3110...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3110 Dental amalgam capsule. (a) Identification. A dental amalgam capsule is a container device in which silver alloy is intended to be mixed with...

  20. 21 CFR 872.3070 - Dental amalgam, mercury, and amalgam alloy.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Dental amalgam, mercury, and amalgam alloy. 872.3070 Section 872.3070 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3070 Dental amalgam,...

  1. Interactions between dental amalgams and the oral environment.

    PubMed

    Marek, M

    1992-09-01

    Dental amalgam fillings interact in a complex way with the environment in the oral cavity as they are subjected to chemical, biological, mechanical, and thermal forces. These forces change the restoration's appearance and properties, while metal ions, amalgam debris, non-metallic corrosion products, and mercury vapor are released into the oral cavity. The phenomena and conditions that affect the amalgam/environment interaction include the chemistry and biochemistry of the environment, formation of biofilms on the amalgam surfaces, existence of localized corrosion cells, galvanic contacts with other metallic restorations, abrasion during mastication, and synergistic effects of the different forces. Corrosion processes result in a degradation of the functional amalgam properties, while tarnishing reactions cause discoloration. Corrosion degradation of amalgam fillings is due mainly to localized corrosion cells in pores and crevices. Corrosion on occlusal surfaces is accelerated by abrasion during mastication, which removes the protective surface films. The average total amounts of metal species, including mercury, released per day in vivo from a restoration have not been determined. Much of the reported indirect evidence for high mercury release rates is either unreliable or controversial. A more detailed investigation is needed and will require the development of more sophisticated techniques of sampling in vivo, as well as both experimental and theoretical modeling in vitro.

  2. Dental amalgam: is this the end?

    PubMed

    Taut, Cristina

    Dental amalgam is a reliable and effective restorative material with a well-established role in modern dentistry. Throughout the years its mercury content and the risks posed to human health were main topics of interest for many scientists. This paper offers a review of the scientific literature on the health and environmental impact of mercury in dentistry published over the last decade. A variety of peer-reviewed, epidemiological and large-scale clinical studies on dental amalgam, as well as published reports of professional and governmental bodies, were organised thematically and analysed. The most relevant findings of the aforementioned literature are reported. No reliance has been placed on unpublished work or publicly available opinions that are not scientifically based. In order to offer an appropriate view on the topic the toxicology, health impacts and possible environmental threats are briefly presented in relation to the relevant literature published in the last ten years. It is almost unanimously accepted that dental amalgam is a safe material, with little or insignificant adverse effect on general health. However, current and mostly unfounded environmental concerns may result in the implementation of new across the board legislation that could lead to a global dental amalgam "phase out".

  3. Determination of light elements in amalgam restorations. [Dental amalgam

    SciTech Connect

    Hanson, A.L.; Jones, K.W.; Kraner, H.W.; Osborne, J.W.; Nelson, G.V.

    1982-01-01

    Rutherford backscattering has been used to measure the major elemental compositions in the near-surface regions of freshly prepared and used samples of dental amalgam. A depletion from bulk stoichiometry of the major elements, which indicates an accumulation of lighter elements on the surface of the materials, has been observed. Increases in the F, Na, Cl, P, O, C, and N concentrations between freshly prepared samples and used samples were measured by observation of gamma rays produced by proton and deuteron induced reactions.

  4. Mercury vapour exposure during dental student training in amalgam removal

    PubMed Central

    2013-01-01

    Background Amalgam that is used for dental fillings contains approximately 50% elemental mercury. During dental student training, amalgam is often removed by drilling without the use of water spray and suction, which are protective measures in preventing mercury aerosol. In this study we measured mercury vapor levels in ambient air during amalgam removal as is typically performed in dental training. Methods Mercury vapor levels in ambient air were measured in a dental school laboratory during removal of amalgam fillings from artificial teeth set into a dental jaw simulator. Mercury vapor was measured under three conditions (25 measurements each): with the simultaneous use of water spray and suction, with the use of suction only, and with the use of neither suction nor water spray. These three conditions are all used during dental student training. Results were compared to Alberta occupational exposure limits for mercury vapor in order to assess potential occupational risk to students. Analysis of variance testing was used to compare data obtained under the three conditions. Results When water spray and suction were used, mercury vapor levels ranged from 4.0 to 19.0 μg/m3 (arithmetic mean = 8.0 μg/m3); when suction only was used, mercury vapor levels ranged from 14.0 to 999.0 (999.0 μg/m3 represents the high limit detection of the Jerome analyzer) (arithmetic mean = 141.0 μg/m3); when neither suction nor water was used, the vapor levels ranged from 34.0 to 796.0 μg/m3 (arithmetic mean = 214.0 μg/m3). Conclusions The Alberta Occupational Health and Safety threshold limit value for mercury vapor over an eight-hour time-weighted period is 25.0 μg/m3. The absolute ceiling for mercury vapor, not to be exceeded at any time, is 125.0 μg/m3. When both water spray and suction were used, mercury vapor levels were consistently below this threshold. When suction without water spray was used, mercury vapor levels exceeded the safety threshold 8% of

  5. Dental devices: classification of dental amalgam, reclassification of dental mercury, designation of special controls for dental amalgam, mercury, and amalgam alloy; technical amendment. Final rule; technical amendment.

    PubMed

    2010-06-11

    The Food and Drug Administration (FDA) published a final rule in the Federal Register of August 4, 2009 (74 FR 38686) which classified dental amalgam as a class II device, reclassified dental mercury from class I to class II, and designated special controls for dental amalgam, mercury, and amalgam alloy. The effective date of the rule was November 2, 2009. The final rule was published with an inadvertent error in the codified section. This document corrects that error. This action is being taken to ensure the accuracy of the agency's regulations.

  6. Renal Effects of Dental Amalgam in Children: The New England Children’s Amalgam Trial

    PubMed Central

    Barregard, Lars; Trachtenberg, Felicia; McKinlay, Sonja

    2008-01-01

    Background Mercury is nephrotoxic and dental amalgam is a source of mercury exposure. Methods Children 6–10 years of age (n = 534) with two or more posterior teeth with caries but no prior amalgam restorations, were randomized to one of two treatments—amalgam or resin composite (white fillings)—used for caries treatment during 5 years of follow-up. The primary outcome was change in IQ, but important secondary outcomes were effects on markers of glomerular and tubular kidney function: urinary excretion of albumin, alpha-1-microglobulin (A1M), γ-glutamyl transpeptidase (γ-GT), and N-acetyl-β-d-glucosaminidase (NAG). These markers were measured on several occasions during the trial, together with urinary mercury and covariates. We evaluated the results using repeated-measures analyses. Results There were no significant differences between treatment groups in average levels of renal biomarkers, nor significant effects of number of dental amalgams on these markers. There was, however, a significantly increased prevalence of microalbuminuria (MA) among children in the amalgam group in years 3–5 (adjusted odds ratio 1.8; 95% confidence interval, 1.1–2.9). Most of these cases are likely to be temporary MA, but 10 children in the amalgam group had MA in both years 3 and 5, versus 2 children in the composite group (p = 0.04). There were no differences in the occurrence of high levels of renal tubular markers (A1M, γ-GT, or NAG). Conclusions The increase in MA may be a random finding, but should be tested further. The results did not support recent findings in an observational study of an effect of low-level mercury on tubular biomarkers in children. PMID:18335109

  7. A significant dose-dependent relationship between mercury exposure from dental amalgams and kidney integrity biomarkers: a further assessment of the Casa Pia children's dental amalgam trial.

    PubMed

    Geier, D A; Carmody, T; Kern, J K; King, P G; Geier, M R

    2013-04-01

    Dental amalgams are a commonly used dental restorative material. Amalgams are about 50% mercury (Hg), and Hg is known to significantly accumulate in the kidney. It was hypothesized that because Hg accumulates in the proximal tubules (PTs), glutathione-S-transferases (GST)-α (suggestive of kidney damage at the level of PT) would be expected to be more related to Hg exposure than GST-π (suggestive of kidney damage at the level of the distal tubules). Urinary biomarkers of kidney integrity were examined in children of 8-18 years old, with and without dental amalgam fillings, from a completed clinical trial (parent study). Our study determined whether there was a significant dose-dependent correlation between increasing Hg exposure from dental amalgams and GST-α and GST-π as biomarkers of kidney integrity. Overall, the present study, using a different and more sensitive statistical model than the parent study, revealed a statistically significant dose-dependent correlation between cumulative exposure to Hg from dental amalgams and urinary levels of GST-α, after covariate adjustment; where as, a nonsignificant relationship was observed with urinary levels of GST-π. Furthermore, it was observed that urinary GST-α levels increased by about 10% over the 8-year course of the study among individuals with an average exposure to amalgams among the study subjects from the amalgam group, in comparison with study subjects with no exposure to dental amalgams. The results of our study suggest that dental amalgams contribute to ongoing kidney damage at the level of the PTs in a dose-dependent fashion.

  8. [Functional dental anatomy and amalgam].

    PubMed

    Tavernier, B; Colon, P

    1989-01-01

    Very often, the functional dental anatomy are reflected during the rehabilitation of posterior quadrants. However, the placement, the shaping in correct relation of the different dental components are indispensable conditions to respect, in order to achieve an adequate integration of the restoration within the neuro-muscular system. A clinical protocol is proposed in order to reconcile the anatomical and biological prerequisite and the setting time of modern alloys.

  9. Mercury exposure and risks from dental amalgam in the US population, post-2000.

    PubMed

    Richardson, G M; Wilson, R; Allard, D; Purtill, C; Douma, S; Gravière, J

    2011-09-15

    Dental amalgam is 50% metallic mercury (Hg) by weight and Hg vapour continuously evolves from in-place dental amalgam, causing increased Hg content with increasing amalgam load in urine, faeces, exhaled breath, saliva, blood, and various organs and tissues including the kidney, pituitary gland, liver, and brain. The Hg content also increases with maternal amalgam load in amniotic fluid, placenta, cord blood, meconium, various foetal tissues including liver, kidney and brain, in colostrum and breast milk. Based on 2001 to 2004 population statistics, 181.1 million Americans carry a grand total of 1.46 billion restored teeth. Children as young as 26 months were recorded as having restored teeth. Past dental practice and recently available data indicate that the majority of these restorations are composed of dental amalgam. Employing recent US population-based statistics on body weight and the frequency of dentally restored tooth surfaces, and recent research on the incremental increase in urinary Hg concentration per amalgam-filled tooth surface, estimates of Hg exposure from amalgam fillings were determined for 5 age groups of the US population. Three specific exposure scenarios were considered, each scenario incrementally reducing the number of tooth surfaces assumed to be restored with amalgam. Based on the least conservative of the scenarios evaluated, it was estimated that some 67.2 million Americans would exceed the Hg dose associated with the reference exposure level (REL) of 0.3 μg/m(3) established by the US Environmental Protection Agency; and 122.3 million Americans would exceed the dose associated with the REL of 0.03 μg/m(3) established by the California Environmental Protection Agency. Exposure estimates are consistent with previous estimates presented by Health Canada in 1995, and amount to 0.2 to 0.4 μg/day per amalgam-filled tooth surface, or 0.5 to 1 μg/day/amalgam-filled tooth, depending on age and other factors.

  10. Oral lichenoid contact lesions to mercury and dental amalgam--a review.

    PubMed

    McParland, Helen; Warnakulasuriya, Saman

    2012-01-01

    Human oral mucosa is subjected to many noxious stimuli. One of these substances, in those who have restorations, is dental amalgam which contains mercury. This paper focuses on the local toxic effects of amalgam and mercury from dental restorations. Components of amalgam may, in rare instances, cause local side effects or allergic reactions referred to as oral lichenoid lesions (OLLs). OLLs to amalgams are recognised as hypersensitivity reactions to low-level mercury exposure. The use of patch testing to identify those susceptible from OLL is explored, and recommendations for removing amalgam fillings, when indicated are outlined. We conclude that evidence does not show that exposure to mercury from amalgam restorations poses a serious health risk in humans, except for an exceedingly small number of hypersensitivity reactions that are discussed.

  11. 21 CFR 872.3110 - Dental amalgam capsule.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Dental amalgam capsule. 872.3110 Section 872.3110 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3110 Dental amalgam capsule. (a) Identification....

  12. 21 CFR 872.3110 - Dental amalgam capsule.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Dental amalgam capsule. 872.3110 Section 872.3110 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3110 Dental amalgam capsule. (a) Identification....

  13. Dental devices: classification of dental amalgam, reclassification of dental mercury, designation of special controls for dental amalgam, mercury, and amalgam alloy. Final rule.

    PubMed

    2009-08-01

    The Food and Drug Administration (FDA) is issuing a final rule classifying dental amalgam into class II, reclassifying dental mercury from class I to class II, and designating a special control to support the class II classifications of these two devices, as well as the current class II classification of amalgam alloy. The three devices are now classified in a single regulation. The special control for the devices is a guidance document entitled, "Class II Special Controls Guidance Document: Dental Amalgam, Mercury, and Amalgam Alloy." This action is being taken to establish sufficient regulatory controls to provide reasonable assurance of the safety and effectiveness of these devices. Elsewhere in this issue of the Federal Register, FDA is announcing the availability of the guidance document that will serve as the special control for the devices.

  14. Patients' experiences of changes in health complaints before, during, and after removal of dental amalgam.

    PubMed

    Sjursen, Therese T; Binder, Per-Einar; Lygre, Gunvor B; Helland, Vigdis; Dalen, Knut; Björkman, Lars

    2015-01-01

    In this article, we explore how patients with health complaints attributed to dental amalgam experienced and gave meaning to changes in health complaints before, during, and after removal of all amalgam fillings. We conducted semistructured qualitative interviews with 12 participants from the treatment group in a Norwegian amalgam removal trial. Interviews took place within a couple months of the final follow-up 5 years after amalgam removal. Using the NVivo9 software, we conducted an explorative and reflective thematic analysis and identified the following themes: Something is not working: betrayed by the body, You are out there on your own, Not being sure of the importance of amalgam removal, The relief experienced after amalgam removal, and To accept, to give up, or to continue the search. We discuss the findings in the context of patients' assigning meaning to illness experiences.

  15. Patients’ experiences of changes in health complaints before, during, and after removal of dental amalgam

    PubMed Central

    Sjursen, Therese T.; Binder, Per-Einar; Lygre, Gunvor B.; Helland, Vigdis; Dalen, Knut; Björkman, Lars

    2015-01-01

    In this article, we explore how patients with health complaints attributed to dental amalgam experienced and gave meaning to changes in health complaints before, during, and after removal of all amalgam fillings. We conducted semistructured qualitative interviews with 12 participants from the treatment group in a Norwegian amalgam removal trial. Interviews took place within a couple months of the final follow-up 5 years after amalgam removal. Using the NVivo9 software, we conducted an explorative and reflective thematic analysis and identified the following themes: Something is not working: betrayed by the body, You are out there on your own, Not being sure of the importance of amalgam removal, The relief experienced after amalgam removal, and To accept, to give up, or to continue the search. We discuss the findings in the context of patients’ assigning meaning to illness experiences. PMID:26112454

  16. [Management of wastes from dental amalgam by dentists in Burkina Faso and Morocco].

    PubMed

    Chala, S; Sawadogo, A; Sakout, M; Abdallaoui, F

    2012-12-01

    Dental amalgam is a metallic restorative material that is used for direct filling of carious lesions since many years. The use of this material generates solid and particulate wastes that present potential challenges to the environment. This study was carried out to assess amalgam use and waste management protocols practiced by Moroccan and Burkinabe dentists. A cross-sectional study was made of 79 in Rabat, Sale and Temara in Morocco and 56 in Ouagadougou, Bobo-Dioulasso in Burkina-Faso. The results showed that 69.5% of dental amalgam waste in Morocco vs 49.9% in Burkina-Faso was disposed with household waste which is a problem for both the environment and a risk to human being. Proper methods of dental amalgam waste disposal should be carried out to prevent indirect mercury poisoning for human.

  17. Mercury from dental amalgam: exposure and risk assessment.

    PubMed

    Koral, Stephen M

    2013-02-01

    There has long been an undercurrent within the dental profession of anti-amalgam sentiment, a "mercury-free" movement. To assess whether anything is or is not scientifically wrong with amalgam, one must look to the vast literature on exposure, toxicology, and risk assessment of mercury. The subject of risk assessment goes straight to the heart of the debate over whether a malgam is safe, or not, for unrestricted use in dentistry in the population at large.

  18. The dental amalgam toxicity fear: a myth or actuality.

    PubMed

    Rathore, Monika; Singh, Archana; Pant, Vandana A

    2012-05-01

    Amalgam has been used in dentistry since about 150 years and is still being used due to its low cost, ease of application, strength, durability, and bacteriostatic effect. When aesthetics is not a concern it can be used in individuals of all ages, in stress bearing areas, foundation for cast-metal and ceramic restorations and poor oral hygiene conditions. Besides all, it has other advantages like if placed under ideal conditions, it is more durable and long lasting and least technique sensitive of all restorative materials, but, concern has been raised that amalgam causes mercury toxicity. Mercury is found in the earth's crust and is ubiquitous in the environment, so even without amalgam restorations everyone is exposed to small but measurable amount of mercury in blood and urine. Dental amalgam restorations may raise these levels slightly, but this has no practical or clinical significance. The main exposure to mercury from dental amalgam occurs during placement or removal of restoration in the tooth. Once the reaction is complete less amount of mercury is released, and that is far below the current health standard. Though amalgam is capable of producing delayed hypersensitivity reactions in some individuals, if the recommended mercury hygiene procedures are followed the risks of adverse health effects could be minimized. For this review the electronic databases and PubMed were used as data sources and have been evaluated to produce the facts regarding amalgam's safety and toxicity.

  19. The Dental Amalgam Toxicity Fear: A Myth or Actuality

    PubMed Central

    Rathore, Monika; Singh, Archana; Pant, Vandana A.

    2012-01-01

    Amalgam has been used in dentistry since about 150 years and is still being used due to its low cost, ease of application, strength, durability, and bacteriostatic effect. When aesthetics is not a concern it can be used in individuals of all ages, in stress bearing areas, foundation for cast-metal and ceramic restorations and poor oral hygiene conditions. Besides all, it has other advantages like if placed under ideal conditions, it is more durable and long lasting and least technique sensitive of all restorative materials, but, concern has been raised that amalgam causes mercury toxicity. Mercury is found in the earth's crust and is ubiquitous in the environment, so even without amalgam restorations everyone is exposed to small but measurable amount of mercury in blood and urine. Dental amalgam restorations may raise these levels slightly, but this has no practical or clinical significance. The main exposure to mercury from dental amalgam occurs during placement or removal of restoration in the tooth. Once the reaction is complete less amount of mercury is released, and that is far below the current health standard. Though amalgam is capable of producing delayed hypersensitivity reactions in some individuals, if the recommended mercury hygiene procedures are followed the risks of adverse health effects could be minimized. For this review the electronic databases and PubMed were used as data sources and have been evaluated to produce the facts regarding amalgam's safety and toxicity. PMID:22778502

  20. Microstructural studies of dental amalgams using analytical transmission electron microscopy

    NASA Astrophysics Data System (ADS)

    Hooghan, Tejpal Kaur

    Dental amalgams have been used for centuries as major restorative materials for decaying teeth. Amalgams are prepared by mixing alloy particles which contain Ag, Sn, and Cu as the major constituent elements with liquid Hg. The study of microstructure is essential in understanding the setting reactions and improving the properties of amalgams. Until the work reported in this dissertation, optical microscopy (OM), scanning electron microscopy (SEM), and x-ray diffractometry (XRD) were used commonly to analyze amalgam microstructures. No previous systematic transmission electron microscopy (TEM) study has been performed due to sample preparation difficulties and composite structure of dental amalgams. The goal of this research was to carry out detailed microstructural and compositional studies of dental amalgams. This was accomplished using the enhanced spatial resolution of the TEM and its associated microanalytical techniques, namely, scanning transmission electron microscopy (STEM), x-ray energy dispersive spectroscopy (XEDS) and micro-microdiffraction (mumuD). A new method was developed for thinning amalgam samples to electron transparency using the "wedge technique." Velvalloy, a low-Cu amalgam, and Tytin, a high-Cu amalgam, were the two amalgams characterized. Velvalloy is composed of a Agsb2Hgsb3\\ (gammasb1)/HgSnsb{7-9}\\ (gammasb2) matrix surrounding unreacted Agsb3Sn (gamma) particles. In addition, hitherto uncharacterized reaction layers between Agsb3Sn(gamma)/Agsb2Hgsb3\\ (gammasb2)\\ and\\ Agsb2Hgsb3\\ (gammasb1)/HgSnsb{7-9}\\ (gammasb2) were observed and analyzed. An Ag-Hg-Sn (betasb1) phase was clearly identified for the first time. In Tytin, the matrix consists of Agsb2Hgsb3\\ (gammasb1) grains. Fine precipitates of Cusb6Snsb5\\ (etasp') are embedded inside the gammasb1 and at the grain boundaries. These precipitates are responsible for the improved creep resistance of Tytin compared to Velvalloy. The additional Cu has completely eliminated the gammasb

  1. Dental amalgam: few proven harmful effects but many ongoing concerns.

    PubMed

    2008-12-01

    (1) Dental amalgam is one of the main sources of exposure to mercury in industrialised countries; (2) At high doses, mercury is both neurotoxic and nephrotoxic. A suspected link exists between chronic exposure to low doses of mercury derived from dental amalgam and renal, neurodegenerative or neurobehavioural disorders, but it has not been established; (3) Some individual cases are troubling, but epidemiological studies show no major effects in the general population. Various hypotheses have been proposed to explain why some people may be more sensitive than others to the effects of low-dose mercury; (4) More and more countries, especially Sweden, recommend that the use of amalgam should be restricted, particularly in pregnant women and children; (5) As part of a global strategy to eliminate mercury, the European Parliament has asked the Commission to draft legislation limiting the use of mercury in dental amalgam; (6) Evaluation of the risk-benefit balances of alternatives to dental amalgam does not provide sufficient data on which to base an informed choice between available options.

  2. Is dental amalgam safe for humans? The opinion of the scientific committee of the European Commission

    PubMed Central

    2011-01-01

    It was claimed by the Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR)) in a report to the EU-Commission that "....no risks of adverse systemic effects exist and the current use of dental amalgam does not pose a risk of systemic disease..." [1, available from: http://ec.europa.eu/health/ph_risk/committees/04_scenihr/docs/scenihr_o_016.pdf]. SCENIHR disregarded the toxicology of mercury and did not include most important scientific studies in their review. But the real scientific data show that: (a) Dental amalgam is by far the main source of human total mercury body burden. This is proven by autopsy studies which found 2-12 times more mercury in body tissues of individuals with dental amalgam. Autopsy studies are the most valuable and most important studies for examining the amalgam-caused mercury body burden. (b) These autopsy studies have shown consistently that many individuals with amalgam have toxic levels of mercury in their brains or kidneys. (c) There is no correlation between mercury levels in blood or urine, and the levels in body tissues or the severity of clinical symptoms. SCENIHR only relied on levels in urine or blood. (d) The half-life of mercury in the brain can last from several years to decades, thus mercury accumulates over time of amalgam exposure in body tissues to toxic levels. However, SCENIHR state that the half-life of mercury in the body is only "20-90 days". (e) Mercury vapor is about ten times more toxic than lead on human neurons and with synergistic toxicity to other metals. (f) Most studies cited by SCENIHR which conclude that amalgam fillings are safe have severe methodical flaws. PMID:21232090

  3. Comparison of release of mercury from three dental amalgams.

    PubMed

    Chew, C L; Soh, G; Lee, A S; Yeoh, T S

    1989-07-01

    Mercury release from dental amalgams has generated considerable concern in recent years and is the subject of this study. Specimens of one admixed high-copper amalgam (Contour), one lathe-cut low-copper amalgam (SDI), and a new tin- and copper-free amalgam claimed to be non-mercury-releasing (Composil) were evaluated for release of mercury when incubated in purified water at 37 degrees C. Measurement of mercury was done by cold-vapor atomic absorption spectrophotometry, and the amount released was expressed as micrograms/cm2/24 hr. Study was conducted over a four-week period. Results show that Contour and SDI released similar insignificant amounts (mean release of less than 0.1 microgram/cm2/24 hr) compared with Composil (mean release of 41.0 micrograms/cm2/24 hr). The difference in release by Composil compared with that by Contour and SDI is highly significant (P less than 0.001). The implications of chronic release of mercury from dental amalgams are discussed. Long-term release studies are in progress.

  4. Maximum bond strength of dental luting cement to amalgam alloy.

    PubMed

    Mojon, P; Hawbolt, E B; MacEntee, M I; Belser, U C

    1989-11-01

    Although dental amalgam is used frequently under artificial crowns for restoration of severely damaged teeth, there is little information available on the bond between luting cements and this alloy. This study was designed for determination of the strength of the bond between a dental amalgam alloy and three crown-luting cements. Cylinders of dental amalgam were joined in pairs, with use of a zinc-phosphate, a glass-ionomer, and an acrylic-adhesive resin cement. The tensile-fracture stress of 45 samples of each cement was measured with a universal testing machine, and subjected to a Weibull analysis. The fractured surfaces were examined under low magnification with use of a light microscope, and at low and high magnifications with use of a scanning electron microscope, for evaluation of the appearance of the fractured joints. The Weibull analysis demonstrated that the adhesive resin cement provided a stronger and more predictable bond than either the zinc-phosphate or the glass-ionomer cement. The appearance of the fractured surfaces gave no indication of the strength of the joints, a feature that is common to brittle materials. The results suggest that crowns placed on teeth offering a large amalgam-alloy surface could be retained more predictably with an adhesive resin cement.

  5. The Chemical Forms of Mercury in Aged and Fresh Dental Amalgam Surfaces

    PubMed Central

    George, Graham N.; Singh, Satya P.; Hoover, Jay; Pickering, Ingrid J.

    2009-01-01

    Mercury-containing dental amalgam is known to be a source of human exposure to mercury. We have explored the use of electron-yield Hg LIII X-ray absorption spectroscopy to characterize the chemical nature of dental amalgam surfaces. We find that the method is practical, and that it shows extensive mercury depletion in the surface of the aged amalgam with significant differences between old and fresh amalgam surfaces. Whereas the fresh amalgam gives spectra that are typical of metallic mercury, the aged amalgam is predominantly β-mercuric sulfide. The toxicological implications of these results are discussed. PMID:19842619

  6. Whole-body imaging of the distribution of mercury released from dental fillings into monkey tissues

    SciTech Connect

    Hahn, L.J.; Kloiber, R.; Leininger, R.W.; Vimy, M.J.; Lorscheider, F.L. )

    1990-11-01

    The fate of mercury (Hg) released from dental silver amalgam tooth fillings into human mouth air is uncertain. A previous report about sheep revealed uptake routes and distribution of amalgam Hg among body tissues. The present investigation demonstrates the bodily distribution of amalgam Hg in a monkey whose dentition, diet, feeding regimen, and chewing pattern closely resemble those of humans. When amalgam fillings, which normally contain 50% Hg, are made with a tracer of radioactive {sup 203}Hg and then placed into monkey teeth, the isotope appears in high concentration in various organs and tissues within 4 wk. Whole-body images of the monkey revealed that the highest levels of Hg were located in the kidney, gastrointestinal tract, and jaw. The dental profession's advocacy of silver amalgam as a stable tooth restorative material is not supported by these findings.

  7. Electrochemical study of insulating properties of dental amalgam bonding polymers.

    PubMed

    Toumelin-Chemla, F; Degrange, M

    1998-06-01

    The standard techniques used for amalgam restorations often result in a lack of adhesion to mineralized dental tissues. The bonding of amalgam with polymer has been suggested to improve its adaptation to dental tissues. Moreover the polymer involved in the bonding should inhibit the corrosion and the diffusion of metallic ions. The aim of this study was to evaluate in vitro the capacity of bonded amalgam to prevent ionic diffusion and migration. In this respect, an original method employing electrochemical techniques was used to determine the leakage current of bonded amalgam restorations. The electrochemical behaviour of conventional and bonded amalgam restorations was compared using a potentiostat driven by a computerized system (Voltamaster, Radiometer Analytical) with software for specific applications such as chronoamperometry or cyclic voltammetry. Samples of recently extracted teeth of young patients were first examined, and then the results were checked by other experimental assays using protected and unprotected copper sticks. The measurements obtained with chronoamperometry (E = +300 mV/SCE) in Ringer's solution at 37 degrees C showed that after polarization for 30 h the oxidation current decreased threefold for bonded samples (10 microA cm(-2)) as compared with the unprotected samples (35 microA cm(-2)). These results, as well as those obtained with the copper wires, demonstrated that even with two layers of adhesive the bonded joint is permeable to ions probably as a result of the hydrophylic properties of HEMA, a component of the adhesive. However, using five layers of adhesive reduced the ionic current by a factor as large as 10(6).

  8. Early failure of Class II resin composite versus Class II amalgam restorations placed by dental students.

    PubMed

    Overton, J D; Sullivan, Diane J

    2012-03-01

    Using the information from remake request slips in a dental school's predoctoral clinic, we examined the short-term survival of Class II resin composite restorations versus Class II dental amalgam restorations. In the student clinic, resin composite is used in approximately 58 percent of Class II restorations placed, and dental amalgam is used in the remaining 42 percent. In the period examined, Class II resin composite restorations were ten times more likely to be replaced at no cost to the patient than Class II dental amalgam restorations. A total of eighty-four resin composite restorations and six amalgam restorations were replaced due to an identified failure.

  9. Dental composites and amalgam and physical development in children.

    PubMed

    Maserejian, N N; Hauser, R; Tavares, M; Trachtenberg, F L; Shrader, P; McKinlay, S

    2012-11-01

    Resin-based composite dental restoration materials may release bisphenol-A, an endocrine-disrupting chemical. Using secondary analysis of a randomized clinical safety trial of amalgam vs. composites, we tested the hypothesis that dental restoration materials affect children's growth. Children (N = 218 boys, N = 256 girls) aged 6 to 10 yrs at baseline with ≥ 2 decayed posterior teeth were randomized to amalgam or composites (bisphenol-A-diglycidyl-dimethacrylate composite for permanent teeth, urethane-dimethacrylate compomer for primary teeth) for treatment of posterior caries throughout follow-up. Primary outcomes for this analysis were 5-year changes in BMI-for-age z-scores, body fat percentage (BF%), and height velocity; exploratory analyses (n = 113) examined age at menarche. Results showed no significant differences between treatment assignment and changes in physical development in boys [(composites vs. amalgam) BF%, 4.9 vs. 5.7, p = 0.49; (BMI-z-score) 0.13 vs. 0.25, p = 0.36] or girls (8.8 vs. 7.7, p = 0.95; 0.36 vs. 0.21, p = 0.49). Children with more treatment on primary teeth had greater increases in BF% regardless of material type. Girls assigned to composites had lower risk of menarche during follow-up (hazard ratio = 0.57, 95% CI 0.35-0.95). Overall, there were no significant differences in physical development over 5 years in children treated with composites or amalgam. Additional studies examining these restoration materials in relation to age at menarche are warranted (clinicaltrials.gov number NCT00065988).

  10. Dental Composites and Amalgam and Physical Development in Children

    PubMed Central

    Maserejian, N.N.; Hauser, R.; Tavares, M.; Trachtenberg, F.L.; Shrader, P.; McKinlay, S.

    2012-01-01

    Resin-based composite dental restoration materials may release bisphenol-A, an endocrine-disrupting chemical. Using secondary analysis of a randomized clinical safety trial of amalgam vs. composites, we tested the hypothesis that dental restoration materials affect children’s growth. Children (N = 218 boys, N = 256 girls) aged 6 to 10 yrs at baseline with ≥ 2 decayed posterior teeth were randomized to amalgam or composites (bisphenol-A-diglycidyl-dimethacrylate composite for permanent teeth, urethane-dimethacrylate compomer for primary teeth) for treatment of posterior caries throughout follow-up. Primary outcomes for this analysis were 5-year changes in BMI-for-age z-scores, body fat percentage (BF%), and height velocity; exploratory analyses (n = 113) examined age at menarche. Results showed no significant differences between treatment assignment and changes in physical development in boys [(composites vs. amalgam) BF%, 4.9 vs. 5.7, p = 0.49; (BMI-z-score) 0.13 vs. 0.25, p = 0.36] or girls (8.8 vs. 7.7, p = 0.95; 0.36 vs. 0.21, p = 0.49). Children with more treatment on primary teeth had greater increases in BF% regardless of material type. Girls assigned to composites had lower risk of menarche during follow-up (hazard ratio = 0.57, 95% CI 0.35-0.95). Overall, there were no significant differences in physical development over 5 years in children treated with composites or amalgam. Additional studies examining these restoration materials in relation to age at menarche are warranted (clinicaltrials.gov number NCT00065988). PMID:22972857

  11. Dental amalgam and urinary mercury concentrations: a descriptive study

    PubMed Central

    2013-01-01

    Background Dental amalgam is a source of elemental and inorganic mercury. The safety of dental amalgam in individuals remains a controversial issue. Urinary mercury concentrations are used to assess chronic exposure to elemental mercury. At present, there are no indications of mercury-associated adverse effects at levels below 5 μg Hg/g creatinine (Cr) or 7 μg Hg/L (urine). The purpose of the present study is to determine the overall urinary mercury level in the Canadian general population in relation to the number of dental amalgam surfaces. Methods Data come from the 2007/09 Canadian Health Measures Survey, which measured urinary mercury concentrations in a nationally representative sample of 5,418 Canadians aged 6–79 years. Urinary mercury concentrations were stratified by sex, age, and number of dental amalgam surfaces. Results The overall mean urinary mercury concentration varied between 0.12 μg Hg/L and 0.31 μg Hg/L or 0.13 μg Hg/g Cr and 0.40 μg Hg/g Cr. In general, females showed slightly higher mean urinary mercury levels than men. The overall 95th percentile was 2.95 μg Hg/L, the 99th percentile was 7.34E μg Hg/L, and the 99.9th percentile was 17.45 μg Hg/L. Expressed as μg Hg/g Cr, the overall 95th percentile was 2.57 μg Hg/g Cr, the 99th percentile was 5.65 μg Hg/g Cr, and the 99.9th percentiles was 12.14 μg Hg/g Cr. Overall, 98.2% of participants had urinary mercury levels below 7 μg Hg/L and 97.7% had urinary mercury levels below 5 μg Hg/g Cr. All data are estimates for the Canadian population. The estimates followed by the letter “E” should be interpreted with caution due to high sampling variability (coefficient of variation 16.6%-33.3%). Conclusions The mean urinary mercury concentrations in the general Canadian population are significantly lower than the values considered to pose any risks for health. PMID:24015978

  12. Dental fillings in Civil War skulls: what do they tell us?

    PubMed

    Glenner, R A; Willey, P; Sledzik, P S; Junger, E P

    1996-11-01

    This article discusses the dental techniques, methods and materials used in the South during the Civil War based on the dental restorations found in the skulls of four confederate soldiers. The skulls display a variety of dental filling materials, including thorium, lead, tin and tin amalgam. These materials were used at a time when more valuable materials, such as gold and silver, were not readily available in the South. PMID:8952248

  13. The Minamata Convention on Mercury: attempting to address the global controversy of dental amalgam use and mercury waste disposal.

    PubMed

    Mackey, Tim K; Contreras, John T; Liang, Bryan A

    2014-02-15

    In October 2013, a new international binding treaty instrument called the Minamata Convention on Mercury opened for signature in Minamata City, Japan, the site of arguably the worst public health and environmental disaster involving mercury contamination. The treaty aims to curb the significant health and environmental impacts of mercury pollution and includes provisions addressing the mining, export and import, storage, and waste management of products containing mercury. Importantly, a provision heavily negotiated in the treaty addresses the use of dental fillings using mercury amalgam, an issue that has been subject to decades of global controversy. Though use of dental amalgam is widespread and has benefits, concerns have been raised regarding the potential for human health risk and environmental damage from emissions and improper waste management. While the Minamata Convention attempts to address these issues by calling for a voluntary phase-down of dental amalgam use and commitment to other measures, it falls short by failing to require binding and measurable targets to achieve these goals. In response, the international community should begin exploring ways to strengthen the implementation of the dental amalgam treaty provisions by establishing binding phase-down targets and milestones as well as exploring financing mechanisms to support treaty measures. Through strengthening of the Convention, stakeholders can ensure equitable access to global oral health treatment while also promoting responsible environmental stewardship.

  14. Amalgam

    SciTech Connect

    Fox, Kevin

    2012-09-05

    Amalgam is a system that allows you to generate collections of files that work with conventional tools but take up minimal extra space on storage. If you already are archiving files in a file system and don't want to make multiple copies of whole files in order to ship the data somewhere then this system is for you. Amalgam consists of tools that allow you to create and get information about '.amalgam' files which contain just the metadata associated with a set of files. It also contains a fuse file system that, using amalgam files, will dynamically create traditional tar files. With this setup, you can see multiple orders of magnitude reduction in storage requirements for temporary data collections.

  15. Amalgam

    2012-09-05

    Amalgam is a system that allows you to generate collections of files that work with conventional tools but take up minimal extra space on storage. If you already are archiving files in a file system and don't want to make multiple copies of whole files in order to ship the data somewhere then this system is for you. Amalgam consists of tools that allow you to create and get information about '.amalgam' files which containmore » just the metadata associated with a set of files. It also contains a fuse file system that, using amalgam files, will dynamically create traditional tar files. With this setup, you can see multiple orders of magnitude reduction in storage requirements for temporary data collections.« less

  16. Immune Function Effects of Dental Amalgam in Children: A Randomized Clinical Trial

    PubMed Central

    Shenker, Bruce J.; Maserejian, Nancy N.; Zhang, Annie; McKinlay, Sonja

    2010-01-01

    Background Dental amalgam is a widely used restorative material containing 50% elemental mercury that emits mercury vapor. No randomized clinical trials have determined whether there are adverse immunologic effects associated with this low-level mercury exposure in children. The objective of this study was to evaluate a sub-population of the New England Children’s Amalgam Trial (NECAT) for in vitro manifestations of immunotoxic effects of dental amalgam. Methods A randomized clinical trial in which children requiring dental restorative treatment were randomized to either amalgam for posterior restorations or resin composite. A total of 66 children, aged 6–10 years, were assessed for total white cell numbers, T-cell, B-cell, neutrophil and monocyte responsiveness over a five-year period. Owing to the small number of participants, the study is exploratory in nature with limited statistical power. Results The mean number of tooth surfaces restored during the five-year period was 7.8 for the amalgam group and 10.1 for composite group. In the amalgam group there was a slight, but not statistically significant, decline in responsiveness of T-cells and monocytes at 5–7 days post treatment; no differences were consistently observed at 6, 12 or 60 months. Conclusions This study confirms that treatment of children with dental amalgams leads to increased, albeit low level, exposure to mercury. In this exploratory analysis of immune function, amalgam exposure did not cause overt immune deficits, although small transient effects were observed 5–7 days post restoration. Clinical implications These findings suggest that immunotoxic effects of amalgam restorations in children need not be a concern when choosing this restorative dental material. PMID:18978388

  17. New science challenges old notion that mercury dental amalgam is safe.

    PubMed

    Homme, Kristin G; Kern, Janet K; Haley, Boyd E; Geier, David A; King, Paul G; Sykes, Lisa K; Geier, Mark R

    2014-02-01

    Mercury dental amalgam has a long history of ostensibly safe use despite its continuous release of mercury vapor. Two key studies known as the Children's Amalgam Trials are widely cited as evidence of safety. However, four recent reanalyses of one of these trials now suggest harm, particularly to boys with common genetic variants. These and other studies suggest that susceptibility to mercury toxicity differs among individuals based on multiple genes, not all of which have been identified. These studies further suggest that the levels of exposure to mercury vapor from dental amalgams may be unsafe for certain subpopulations. Moreover, a simple comparison of typical exposures versus regulatory safety standards suggests that many people receive unsafe exposures. Chronic mercury toxicity is especially insidious because symptoms are variable and nonspecific, diagnostic tests are often misunderstood, and treatments are speculative at best. Throughout the world, efforts are underway to phase down or eliminate the use of mercury dental amalgam.

  18. Estimation by a 24-hour study of the daily dose of intra-oral mercury vapor inhaled after release from dental amalgam

    SciTech Connect

    Berglund, A. )

    1990-10-01

    The difficulties associated with estimations of daily doses of inhaled mercury vapor released from dental amalgam are considerable. Existing data are often unreliable, especially if they are based on a single or a small series of samples of intra-oral concentrations of mercury vapor before, during, and after chewing stimulation. In the present paper, the aim was to obtain a more representative estimation of the daily dose of mercury vapor inhaled from amalgam fillings by measurement of amounts of mercury vapor released in the oral cavity during 24 h, under conditions that were as normal as possible. A series of measurements was carried out on each of 15 subjects, with at least nine occlusal surfaces restored with dental amalgam, and on five subjects without any amalgam restorations. The subjects had to follow a standardized schedule for 24 h, whereby they ate, drank, and brushed their teeth at pre-determined time periods. The amount of mercury vapor released per time unit was measured at intervals of 30-45 min by means of a measuring system based on atomic absorption spectrophotometry. None of the subjects was professionally exposed to mercury, and all of their amalgam fillings were more than one year old. Study casts were made for each subject, and the area of the amalgam surfaces was measured. Samples of urine and saliva were analyzed so that values for the mercury concentrations and the rate of release of mercury into saliva could be obtained. The average frequency of fish meals per month was noted.

  19. The Chemistry of Modern Dental Filling Materials.

    ERIC Educational Resources Information Center

    Nicholson, John W.; Anstice, H. Mary

    1999-01-01

    Discusses materials used by dentists to restore teeth after decay has been removed. Shows how dental-material science is an interdisciplinary field in which chemistry plays a major part. Reviews the many developments polymer chemistry has contributed to the field of dental fillings. (CCM)

  20. Increased mercury release from dental amalgam restorations after exposure to electromagnetic fields as a potential hazard for hypersensitive people and pregnant women.

    PubMed

    Mortazavi, Ghazal; Mortazavi, S M J

    2015-01-01

    Over the past decades, the use of common sources of electromagnetic fields such as Wi-Fi routers and mobile phones has been increased enormously all over the world. There is ongoing concern that exposure to electromagnetic fields can lead to adverse health effects. It has recently been shown that even low doses of mercury are capable of causing toxicity. Therefore, efforts are initiated to phase down or eliminate the use of mercury amalgam in dental restorations. Increased release of mercury from dental amalgam restorations after exposure to electromagnetic fields such as those generated by MRI and mobile phones has been reported by our team and other researchers. We have recently shown that some of the papers which reported no increased release of mercury after MRI, may have some methodological errors. Although it was previously believed that the amount of mercury released from dental amalgam cannot be hazardous, new findings indicate that mercury, even at low doses, may cause toxicity. Based on recent epidemiological findings, it can be claimed that the safety of mercury released from dental amalgam fillings is questionable. Therefore, as some individuals tend to be hypersensitive to the toxic effects of mercury, regulatory authorities should re-assess the safety of exposure to electromagnetic fields in individuals with amalgam restorations. On the other hand, we have reported that increased mercury release after exposure to electromagnetic fields may be risky for the pregnant women. It is worth mentioning that as a strong positive correlation between maternal and cord blood mercury levels has been found in some studies, our findings regarding the effect of exposure to electromagnetic fields on the release of mercury from dental amalgam fillings lead us to this conclusion that pregnant women with dental amalgam fillings should limit their exposure to electromagnetic fields to prevent toxic effects of mercury in their fetuses. Based on these findings, as infants

  1. Creep-fatigue as a possible cause of dental amalgam margin failure.

    PubMed

    Williams, P T; Hedge, G L

    1985-03-01

    Fracture of the margins is the most common cause of failure of dental amalgam restorations. Both corrosion and creep have been identified as possible contributors to this type of failure. The stresses that induce creep may arise from the continued setting expansion of the amalgam, the formation of corrosion products, mastication, or from the thermal expansion of the amalgam during ingestion of hot foods. The latter two are low-frequency cyclic stresses. The amalgams used in dentistry have fusion temperatures only about 40 degrees C above mouth temperature, and they experience grain boundary sliding during creep deformation. Since grain boundary sliding, low-frequency cyclic stresses, and a temperature near the fusion temperature of the alloy are prerequisites for so-called "creep-fatigue fracture", this type of fracture may contribute to amalgam margin failure. Amalgam made from seven different alloys was condensed into stainless steel dies. After being allowed to set for seven days, the specimens were thermally cycled between 4 degrees C and 50 degrees C for 500 and 1000 cycles. Amalgam margin integrity was evaluated by scanning electron microscopy both before and after each cycling period. The amount of margin fracture was calculated after 1000 cycles. Thermal cycling of amalgam restorations placed in stainless steel dies resulted in predominantly intergranular fracturing of the amalgam margins, indicating that creep-fatigue failure may be a significant contributor to in vivo margin fracturing. PMID:3855901

  2. A scanning transmission electron microscopy study of two dental amalgams.

    PubMed

    Williams, K R

    1983-10-01

    Two fully aged amalgam alloys were examined using a scanning transmission electron microscope both in the transmission and scanning mode. The dispersed type amalgam containing a distribution of silver-copper spheres in addition to the Ag3Sn powder showed a markedly reduced gamma 1 grain size compared to a conventional Ag3Sn type amalgam. It is suggested that the increased compressive creep strength of the dispersed type material is a direct result of the reduced gamma 1 grain size and not due to a dispersion hardening effect from the cores of the remaining Ag-Cu spheres. Similarly, the formation of complex Cu-Sn intermediate phases at the Ag-Cu sphere surfaces are unlikely to lead to a dispersion strengthening effect. It is postulated that the reduced grain size in high copper amalgams is a consequence of the enhanced nucleating effect of a copper based phase on gamma 1. PMID:6640049

  3. Corrosion of dental amalgams in solutions of organic acids.

    PubMed

    Palaghias, G

    1986-06-01

    A conventional and two high copper amalgams were tested in 0.5% aqueous solutions of acetic, formic, lactic and succinic acid. The corrosion behavior of the amalgams in the different solutions was evaluated by analyzing the soluble corrosion products using an atomic absorption spectrophotometer every month during a 6-month experimental period. The high copper amalgams showed a high dissolution rate in formic and lactic acid solutions from the initial stages of immersion when compared to the conventional. Later a marked decrease of the dissolution rate could be observed but it still remained at high levels. In acetic acid the amounts of elements dissolved from high copper amalgams were much less. Conventional amalgam released much smaller amounts of elements in almost all solutions tested except in the case of silver in lactic acid. Finally, in succinic acid solution, the amounts of elements dissolved were unexpectedly small considering the low pH of the solution and the dissolution rates of the amalgams in the other organic acid solutions. PMID:3461548

  4. Long-term clinical evaluation of fracture and pulp injury following glass-ionomer cement or composite resin applied as a base filling in teeth restored with amalgam.

    PubMed

    De C Luz, M A; Ciaramicoli-Rodrigues, M T; Garone Netto, N; De Lima, A C

    2001-07-01

    The aim of this research was to analyse the long-term clinical behaviour of two dental materials applied as filling under silver amalgam restorations: glass-ionomer cement (GIC) and composite resin with adhesive system (CR). In this study, 117 posterior teeth (29 premolars and 88 molars) were selected with carious lesions which resulted in great loss of dentin and cusps with unsupported enamel. After caries removal, cavities were prepared and totally filled with GIC or with CR. In a following visit, new cavities were prepared, leaving the employed filling material as a base and support for the enamel, which were then restored with silver amalgam. Restorations were evaluated periodically after 6 months and up to 5 years. Both fracture and pulpal involvement rates were low. Although differences could be observed in the behaviour of the materials, statistical survival estimation showed that the performances of GIC and CR as filling material were similar. There was a significant association both between kind of tooth (molar or premolar) and long-term survival of the restorations; and between degree of unsupported enamel and the same long-term survival. Our results confirmed that the technique in which GIC or CR are used as filling under silver amalgam restorations is clinically acceptable. PMID:11422695

  5. Influence of dental biofilm on release of mercury from amalgam exposed to carbamide peroxide.

    PubMed

    Steinberg, Doron; Blank, Ori; Rotstein, Ilan

    2003-10-15

    Tooth bleaching is a popular procedure in modern aesthetic dentistry. Bleaching agents may affect amalgam restorations by altering the release of mercury. The aim of this study was to explore the effect of biofilm-coated amalgam restorations on the release of mercury in the presence of carbamide peroxide. Samples of SDI and Valliant amalgams were submerged for either 14 days or 7 months in buffered KCl after which they were coated with saliva, bacteria, and polysaccharides. The samples were exposed to 10% carbamide peroxide (CP) for 24 h. The amount of mercury released was examined for 120 h. Results showed that most of mercury release occurred within the first 24 h, after which the release rate decreased sharply. After 120 h the release of mercury from the tested samples was minimal and similar to the control group. The presence of biofilm coating on the amalgam samples did not induce the release of mercury but tended to reduce mercury release into the surrounding environment. CP induces the release of mercury from amalgam samples. However, the presence of biofilm did not prevent large amounts of mercury release from amalgam coated with biofilms and exposed to CP. This study indicates that dental biofilm may retard the release of mercury from amalgam restorations.

  6. Monte Carlo dose calculation in dental amalgam phantom.

    PubMed

    Aziz, Mohd Zahri Abdul; Yusoff, A L; Osman, N D; Abdullah, R; Rabaie, N A; Salikin, M S

    2015-01-01

    It has become a great challenge in the modern radiation treatment to ensure the accuracy of treatment delivery in electron beam therapy. Tissue inhomogeneity has become one of the factors for accurate dose calculation, and this requires complex algorithm calculation like Monte Carlo (MC). On the other hand, computed tomography (CT) images used in treatment planning system need to be trustful as they are the input in radiotherapy treatment. However, with the presence of metal amalgam in treatment volume, the CT images input showed prominent streak artefact, thus, contributed sources of error. Hence, metal amalgam phantom often creates streak artifacts, which cause an error in the dose calculation. Thus, a streak artifact reduction technique was applied to correct the images, and as a result, better images were observed in terms of structure delineation and density assigning. Furthermore, the amalgam density data were corrected to provide amalgam voxel with accurate density value. As for the errors of dose uncertainties due to metal amalgam, they were reduced from 46% to as low as 2% at d80 (depth of the 80% dose beyond Zmax) using the presented strategies. Considering the number of vital and radiosensitive organs in the head and the neck regions, this correction strategy is suggested in reducing calculation uncertainties through MC calculation.

  7. Effects of palladium addition on properties of dental amalgams.

    PubMed

    Chung, K

    1992-05-01

    Palladium-containing amalgam alloys were developed utilizing the atomization method. Single-compositional type alloys were fabricated and palladium was substituted for silver in concentrations up to 5 w/o. Alloy powder with a particle size of less than 45 microns was collected and triturated with mercury. Creep, compressive strength and dimensional change tests were performed according to ADA Specification No. 1 along with controls of Tytin, Valiant and Valiant-Ph.D. Values for creep decreased and compressive strength increased markedly with additions of palladium. Current densities of the experimental amalgams containing palladium were determined to be an order of magnitude less than the original amalgams in the electrochemical test. A trend of positive relationships between properties and palladium additions was indicated.

  8. Steady-state transfer and depletion kinetics of mercury from amalgam fillings.

    PubMed

    Halbach, S; Welzl, G; Kremers, L; Willruth, H; Mehl, A; Wack, F X; Hickel, R; Greim, H

    2000-10-01

    In 29 volunteers with a low amalgam load, the number of amalgam-covered tooth surfaces and the occlusal area of the fillings were determined. Before and at select times after removal of all amalgams, concentrations of total mercury were measured by cold-vapor atomic absorption in plasma and erythrocytes as well as in urine together with the excretion rate. Absorbed daily doses were estimated from intraoral Hg emission by two separate methods. The transfer of Hg from the fillings via the oral cavity and blood to urinary excretion was evaluated according to the most representative combination of parameters. This consisted of occlusal area (1), absorbed dose (2), Hg concentration in plasma (3) and urinary excretion (4). Pairwise correlation coefficients were 0.49 for parameters 1 vs. 2, and 0.75 each for parameters 2 vs. 3 and 3 vs. 4. Within 9 days after removal of the fillings, a transient increase in Hg levels was observed in plasma only; in the group without a rubber dam, concentrations increased significantly above pre-removal values at days 1 and 3, whereas they decreased significantly below pre-removal values at day 30 in the rubber-dam group and at day 100 in both groups. Excretion rates decreased significantly at day 100 in the protected group. Peak plasma-Hg was 0.6 ng/ml on average at day 1 and decreased with halftimes of 3 and 43 days in subjects protected by a rubber dam. The results indicated that concentrations of total mercury in plasma responded rapidly to changes in the amalgam status and reflected the actual absorption most reliably. Notably, plasma-Hg levels were sensitive enough to detect a transient attenuation of the additional exposure after using a rubber dam during the removal of only a few fillings. However, being small in magnitude and lasting 100 days at best, the rubber-dam effect had minor toxicological relevance.

  9. Biomarkers of kidney integrity in children and adolescents with dental amalgam mercury exposure: findings from the Casa Pia children's amalgam trial.

    PubMed

    Woods, James S; Martin, Michael D; Leroux, Brian G; DeRouen, Timothy A; Bernardo, Mario F; Luis, Henrique S; Leitão, Jorge G; Kushleika, John V; Rue, Tessa C; Korpak, Anna M

    2008-11-01

    Mercury is toxic to the kidney, and dental amalgam is a source of mercury exposure. Few studies have evaluated the effects of dental amalgam on kidney function in a longitudinal context in children. Here, we evaluated urinary concentrations of glutathione S-transferases (GSTs) alpha and pi as biomarkers of renal proximal and distal tubular integrity, respectively, and albumin as a biomarker of glomerular integrity in children and adolescents 8-18 years of age over a 7-year course of dental amalgam treatment. Five hundred seven children, 8-12 years of age at baseline, participated in a clinical trial to evaluate the neurobehavioral and renal effects of dental amalgam in children. Subjects were randomized to either dental amalgam or resin composite treatments. Urinary GSTs alpha and pi, albumin, and creatinine concentrations were measured at baseline and annually in all subjects. Results were evaluated using linear regression analysis. GST-alpha concentrations were similar between treatment groups and in each sex and race (white vs. non-white) group in each follow-up year. GST-pi levels tended upward over the course of follow-up by four- to six-fold. This increase was seen in all groups irrespective of the treatment, race, or gender. Females had GST-pi levels approximately twice those of males at all ages. Albumin concentrations were constant throughout the follow-up period and did not differ by treatment, although females had 39% higher albumin levels than males. Additionally, we found no significant effects of amalgam treatment on the proportion of children with microalbuminuria (>30 mg/g creatinine). These findings are relevant within the context of children's health risk assessment as relates to the safety of mercury exposure from dental amalgam on kidney function. These data also provide normative values for sensitive indices of renal functional integrity that may serve in the evaluation of children and adolescents with renal disorders.

  10. Biomarkers of kidney integrity in children and adolescents with dental amalgam mercury exposure: Findings from the Casa Pia children's amalgam trial

    SciTech Connect

    Woods, James S. Martin, Michael D.; Leroux, Brian G.; DeRouen, Timothy A.; Bernardo, Mario F.; Luis, Henrique S.; Leitao, Jorge G.; Kushleika, John V.; Rue, Tessa C.; Korpak, Anna M.

    2008-11-15

    Mercury is toxic to the kidney, and dental amalgam is a source of mercury exposure. Few studies have evaluated the effects of dental amalgam on kidney function in a longitudinal context in children. Here, we evaluated urinary concentrations of glutathione S-transferases (GSTs) {alpha} and {pi} as biomarkers of renal proximal and distal tubular integrity, respectively, and albumin as a biomarker of glomerular integrity in children and adolescents 8-18 years of age over a 7-year course of dental amalgam treatment. Five hundred seven children, 8-12 years of age at baseline, participated in a clinical trial to evaluate the neurobehavioral and renal effects of dental amalgam in children. Subjects were randomized to either dental amalgam or resin composite treatments. Urinary GSTs {alpha} and {pi}, albumin, and creatinine concentrations were measured at baseline and annually in all subjects. Results were evaluated using linear regression analysis. GST-{alpha} concentrations were similar between treatment groups and in each sex and race (white vs. non-white) group in each follow-up year. GST-{pi} levels tended upward over the course of follow-up by four- to six-fold. This increase was seen in all groups irrespective of the treatment, race, or gender. Females had GST-{pi} levels approximately twice those of males at all ages. Albumin concentrations were constant throughout the follow-up period and did not differ by treatment, although females had 39% higher albumin levels than males. Additionally, we found no significant effects of amalgam treatment on the proportion of children with microalbuminuria (>30 mg/g creatinine). These findings are relevant within the context of children's health risk assessment as relates to the safety of mercury exposure from dental amalgam on kidney function. These data also provide normative values for sensitive indices of renal functional integrity that may serve in the evaluation of children and adolescents with renal disorders.

  11. Dental silver tooth fillings: A source of mercury exposure revealed by whole-body image scan and tissue analysis

    SciTech Connect

    Hahn, L.J.; Kloiber, R.; Vimy, M.J.; Takahashi, Y.; Lorscheider, F.L. )

    1989-12-01

    Mercury (Hg) vapor is released from dental silver tooth fillings into human mouth air after chewing, but its possible uptake routes and distribution among body tissues are unknown. This investigation demonstrates that when radioactive 203Hg is mixed with dental Hg/silver fillings (amalgam) and placed in teeth of adult sheep, the isotope will appear in various organs and tissues within 29 days. Evidence of Hg uptake, as determined by whole-body scanning and measurement of isotope in specific tissues, revealed three uptake sites: lung, gastrointestinal, and jaw tissue absorption. Once absorbed, high concentrations of dental amalgam Hg rapidly localize in kidneys and liver. Results are discussed in view of potential health consequences from long-term exposure to Hg from this dental material.

  12. 75 FR 33169 - Dental Devices: Classification of Dental Amalgam, Reclassification of Dental Mercury, Designation...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-11

    ... Administration (FDA) published a final rule in the Federal Register of August 4, 2009 (74 FR 38686) which... (powder), which is composed primarily of silver, tin, and copper (74 FR 38686). The final rule classified... previous classification of amalgam alloy in the codified section of the final rule (74 FR 38686 at...

  13. Mercury exposure in the work place and human health: dental amalgam use in dentistry at dental teaching institutions and private dental clinics in selected cities of Pakistan.

    PubMed

    Khwaja, Mahmood A; Nawaz, Sadaf; Ali, Saeed Waqar

    2016-03-01

    During the past two decades, mercury has come under increasing scrutiny with regard to its safety both in the general population and in occupationally exposed groups. It's a growing issue of global concern because of its adverse environmental and health impacts. Very few investigations on mercury amalgam use in the dentistry sector have been carried out in South Asia and there is little data reported on mercury contamination of indoor/outdoor air at dental sites. According to an earlier SDPI study, reported in 2013, alarmingly high mercury levels were observed in air (indoor as well as outdoor) at 11 of the 34 visited dental sites (17 dental teaching institutions, 7 general hospitals & 10 dental clinics) in five main cities of Pakistan. 88% of the sites indicated indoor mercury levels in air above the USA EPA reference level of 300 ng/m3. According to our study, carried out at 38 dental teaching institutions in 12 main cities (in Khyber Pakhtunkhwa, Punjab and Sindh provinces) of Pakistan, respondents were of the opinion that the currently offered BDS curriculum does not effectively guide outgoing dental professionals and does not provide them adequate knowledge and training about mercury/mercury amalgam and other mercury related human health and mercury waste issues. 90% of respondents supported the review and revision of the present dental curriculum offered at dental teaching institutions in the country, at the earliest. A study has also been conducted to assess the status of mercury amalgam use in private dental clinics in Gilgit, Hunza, Peshawar, Rawalpindi and Islamabad. More than 90 private dental clinics were visited and dental professionals/private clinics in-charge were interviewed during June-July, 2015. The focus areas of the study were Hg amalgam toxicity, its waste management practices and safety measures practiced among the dental practitioners. In the light of the findings described and discussed in this brief report, to safeguard public health and

  14. Mercury exposure in the work place and human health: dental amalgam use in dentistry at dental teaching institutions and private dental clinics in selected cities of Pakistan.

    PubMed

    Khwaja, Mahmood A; Nawaz, Sadaf; Ali, Saeed Waqar

    2016-03-01

    During the past two decades, mercury has come under increasing scrutiny with regard to its safety both in the general population and in occupationally exposed groups. It's a growing issue of global concern because of its adverse environmental and health impacts. Very few investigations on mercury amalgam use in the dentistry sector have been carried out in South Asia and there is little data reported on mercury contamination of indoor/outdoor air at dental sites. According to an earlier SDPI study, reported in 2013, alarmingly high mercury levels were observed in air (indoor as well as outdoor) at 11 of the 34 visited dental sites (17 dental teaching institutions, 7 general hospitals & 10 dental clinics) in five main cities of Pakistan. 88% of the sites indicated indoor mercury levels in air above the USA EPA reference level of 300 ng/m3. According to our study, carried out at 38 dental teaching institutions in 12 main cities (in Khyber Pakhtunkhwa, Punjab and Sindh provinces) of Pakistan, respondents were of the opinion that the currently offered BDS curriculum does not effectively guide outgoing dental professionals and does not provide them adequate knowledge and training about mercury/mercury amalgam and other mercury related human health and mercury waste issues. 90% of respondents supported the review and revision of the present dental curriculum offered at dental teaching institutions in the country, at the earliest. A study has also been conducted to assess the status of mercury amalgam use in private dental clinics in Gilgit, Hunza, Peshawar, Rawalpindi and Islamabad. More than 90 private dental clinics were visited and dental professionals/private clinics in-charge were interviewed during June-July, 2015. The focus areas of the study were Hg amalgam toxicity, its waste management practices and safety measures practiced among the dental practitioners. In the light of the findings described and discussed in this brief report, to safeguard public health and

  15. A study of alternative metal particle structures and mixtures for dental amalgams based on mercury additions.

    PubMed

    Marquez, J A; Murr, L E; Agüero, V

    2000-08-01

    The perception that mercury in dental amalgam is toxic to the human organism has prompted worldwide efforts by the scientific community to develop alternative amalgam-like materials that utilize little or no mercury. In this investigation, an attempt is made to develop a new dental alloy system by adding liquid mercury to silver-coated Ag4Sn intermetallic particles in lesser amounts than are used in conventional amalgam alloys. An effort to precipitate the important eta-prime (Cu6Sn5) phase was made by adding pure Cu and Sn powders to the alloy formulation during trituration. Tytin a popular Ag-Sn-Cu single-composition, spray-atomized conventional dental alloy was used as the control to obtain baseline data for comparisons of microstructures and mechanical properties. Amalgamation of the coated particles with mercury, with or without the addition of Cu and Sn powders, mostly produced specimens with chemically non-coherent microstructures that were relatively weak in compression. These results were due, in part, to mercury's inability to chemically wet the Ag-coated particles and Cu and Sn powders because of naturally occurring surface oxide films. The strongest specimens tested had silver dendritic coatings, resulting in compression strength values up to 40% of the control's. Their higher strength is attributed to mechanical interlocking at the particle/matrix interfaces.

  16. Evidence summary: which dental liners under amalgam restorations are more effective in reducing postoperative sensitivity?

    PubMed

    Nasser, Mona

    2011-06-10

    Since August 2009, members of the Primary Care Dentistry Research Forum (www.dentistryresearch.org) have taken part in an online vote to identify questions in day-to-day practice that they felt most needed to be answered with conclusive research. The question that receives the most votes each month forms the subject of a critical appraisal of the relevant literature. Each month a new round of voting takes place to decide which further questions will be reviewed. Dental practitioners and dental care professionals are encouraged to take part in the voting and submit their own questions to be included in the vote by joining the website. The paper below details a summary of the findings of the ninth critical appraisal. In order to address the question raised by dentistry research forum, first a search was conducted for systematic reviews on the topic. There was one systematic review retrieved comparing bonded amalgam restorations versus non-bonded amalgam restorations. However, there was no other systematic review identified assessing the effectiveness of dental liners under amalgam restorations in general. Therefore, a search was conducted for any randomised controlled trial (RCT) comparing use of a lining under amalgam restorations versus no lining or RCTs comparing differing lining materials under amalgam against each other. There were eight relevant RCTs identified. Due to the low quality, small sample sizes or lack of adequate reporting of the outcome data, the evidence is inadequate to claim or refute a difference in postoperative sensitivity between different dental liners. Further well-conducted RCTs are needed to answer this question. These RCTs would be preferably included and synthesised in a systematic review.

  17. Removal of dental filling materials by Er:YAG laser radiation

    NASA Astrophysics Data System (ADS)

    Hibst, Raimund; Keller, Ulrich

    1991-05-01

    In previous reports it could be shown that pulsed Er:YAG laser radiation is effective for the removal of dental enamel, dentin, and caries. Damage to the adjacent hard substances is minimal. Temperature measurements and animal studies revealed that thermal pulp damage can be avoided. The experimental results make the Er:YAG laser promising for the preparation of dental cavities. In many cases patients already have fillings which have to be removed. In the present work, investigation is made of the effect of Er:YAG laser radiation on various restorative filling materials. The experiments demonstrate that removal is possible for all tested cements, composites and amalgam. Ablation efficiency is comparable to that of enamel and dentin, and thus sufficient for practical applications. Morphology of crater walls indicates greater thermal side effects than for natural dental hard substances.

  18. Effect of Surface Polishing on Mercury Release from Dental Amalgam After Treatment 16% Carbamide Peroxide Gel

    PubMed Central

    Azarsina, M.; Kasraei, Sh.; Masoum, T.; Khamverdi, Z.

    2011-01-01

    Objectives: This study evaluated the effect of surface polishing on mercury release from dental amalgam after treatment with 16% carbamide peroxide gel. Materials and Methods: Ninety-six samples from two different amalgam brands were prepared in truncated cone-shaped PVC polymer molds with an external surface area of 195 mm2. Half of the specimens were polished with green and red rubber, a brush and tin oxide paste at low speed. Samples were treated with 16% carbamide peroxide gel in tubes containing 3 mL of carbamide peroxide gel and 0.1 mL of distilled water for 14 and 28 hours. Subsequently, carbamide peroxide gel on the sample surfaces was rinsed away with 7.0 mL of distilled water until the volume of each tube increased to 10 mL. The mercury level of each solution was measured using the VAV–440 mercury analyzer system. Considering the surface area of each amalgam disc, mercury amounts were calculated in μg/mm2. Data were analyzed using two-way ANOVA. Results: There were significant differences between the mean levels of mercury release from polished vs. unpolished amalgam surfaces after treatment with 16% carbamide peroxide. Increasing the storage time from 14 to 28 hours did not result in significant changes in the amount of mercury release. There was no significant interaction effect between amalgam surface polish and storage time statistically. Conclusion: Polished amalgam restorations release less mercury after treatment with carbamide peroxide bleaching gel in comparison with unpolished amalgam restorations. PMID:21998805

  19. Sealing ability of MTA, Super EBA, Vitremer and amalgam as root-end filling materials.

    PubMed

    Pereira, Cecília Luiz; Cenci, Maximiliano Sérgio; Demarco, Flávio Fernando

    2004-01-01

    This study evaluated the root-end sealing ability of mineral trioxide aggregate (MTA Angelus), reinforced zinc oxide-eugenol cement (Super EBA), resin-modified glass ionomer (Vitremer) and zinc-free amalgam (GS-80) (control). The root canals of eighty human lower molars were accessed, cleansed, shaped and obturated. Apexes were resected and cavities were prepared. Teeth were divided into 4 groups of 40 cavities, root-end filled with the materials, and immersed in methylene blue for 72 h at 37 degrees C. Roots were then sectioned transversally at each millimeter and evaluated under magnification, observing the dye penetration in each section. Data were evaluated using Kruskal-Wallis test at a 5% level of significance, showing the differences among all materials (p < 0.001). The crescent order of microleakage was MTA < Vitremer < Super EBA < amalgam. Higher leakage levels were observed in the first millimeter sections of amalgam, Vitremer and MTA, when compared with the third millimeter section (p < 0.05).

  20. Corrosion of dental amalgam and mercury vapor emission in vitro.

    PubMed

    Moberg, L E

    1988-10-01

    Amalgam specimens were immersed for 30 days in 1) water, 2) 0.9% NaCl in water, 3) 0.9% NaCl and 10 mM phosphate buffer in water, and 4) 0.9% NaCl, 7.7 mM phosphate, and 6.1 mM citric acid in water. The solutions were stored in stoppered glass tubes. Hg-drops were immersed in solutions 1, 2, and 3. The concentration of mercury vapor in the air above the solutions was measured once a day. After 30 days the amounts of Cu, Zn, Hg, and Ag in the solutions were analyzed by atomic absorption spectrophotometry. The results showed that 0.9% NaCl alone or in combination with the additives increased the amounts of elements released into the solutions. The concentration of Hg0 in the glass tubes increased with the amount of Hg in the solutions, with the exception of solution No. 3, from which significantly less Hg0 evaporated. The results indicate that the composition of the saliva, oral hygiene and dietary factors may be determinants of Hg0 emission from amalgams in the oral cavity.

  1. Need for informed consent for dentists who use mercury amalgam restorative material as well as technical considerations in removal of dental amalgam restorations.

    PubMed

    Edlich, Richard F; Greene, Jill Amanda; Cochran, Amy A; Kelley, Angela R; Gubler, K Dean; Olson, Brianna M; Hudson, Mary Anne; Woode, Dayna R; Long, William B; McGregor, Walter; Yoder, Carolyn; Hopkins, Debra B; Saepoff, Jessica P

    2007-01-01

    Amalgam restorative material generally contains 50% mercury (Hg) in a complex mixture of copper, tin, silver, and zinc. It has been well documented that this mixture continually emits mercury vapor, which is dramatically increased by chewing, eating, brushing, and drinking hot liquids. Mercury has been demonstrated to have damaging effects on the kidney, central nervous system, and cardiovascular system, and has been implicated in gingival tattoos. While mercury amalgams may result in detrimental exposure to the patient, they can also be a danger in dental practices. In Europe, the federal governments of Norway, Finland, Denmark, and Sweden have enacted legislation requiring that dental patients receive informed consent information about the dental restorative material that will be used. In the United States, a few state governments have enacted informed consent legislation for dental patients receiving dental restorations. These state legislations were enacted by Maine, California, Connecticut, and Vermont. It is a sad tragedy that mercury is causing such health damage to many people. The American Dental Association has said for the past 150 years that the mercury in amalgam is safe and does not leak; however, no clinical studies were ever done and the Food and Drug Administration approved amalgam under a grandfather clause. Subsequent studies have shown this claim of safety not to be true. Over ten years ago, the Federation of American Societies for Experimental Biology Journal published a comprehensive article calling mercury restorative material a major source of mercury exposure to the U.S. population. The authors of this paper recommend that federal and state legislation be passed throughout our country to ensure that consent forms are given to patients receiving silver-mercury amalgam restorative material.

  2. Neurodevelopmental outcomes at 5 years in children exposed prenatally to maternal dental amalgam: the Seychelles Child Development Nutrition Study.

    PubMed

    Watson, Gene E; van Wijngaarden, Edwin; Love, Tanzy M T; McSorley, Emeir M; Bonham, Maxine P; Mulhern, Maria S; Yeates, Alison J; Davidson, Philip W; Shamlaye, Conrad F; Strain, J J; Thurston, Sally W; Harrington, Donald; Zareba, Grazyna; Wallace, Julie M W; Myers, Gary J

    2013-01-01

    Limited human data are available to assess the association between prenatal mercury vapor (Hg⁰)) exposure from maternal dental amalgam restorations and neurodevelopment of children. We evaluated the association between maternal dental amalgam status during gestation and children's neurodevelopmental outcomes at 5 years in the Seychelles Child Development Nutrition Study (SCDNS). Maternal amalgam status was determined prospectively in a longitudinal cohort study examining the associations of prenatal exposure to nutrients and methylmercury (MeHg) with neurodevelopment. A total of 236 mother-child pairs initially enrolled in the SCDNS in 2001 were eligible to participate. Maternal amalgam status was measured as number of amalgam surfaces (the primary metric) and number of occlusal points. The neurodevelopmental assessment battery was comprised of age-appropriate tests of cognitive, language, and perceptual functions, and scholastic achievement. Linear regression analysis controlled for MeHg exposure, maternal fatty acid status, and other covariates relevant to child development. Maternal amalgam status evaluation yielded an average of 7.0 surfaces (range 0-28) and 11.0 occlusal points (range 0-40) during pregnancy. Neither the number of maternal amalgam surfaces nor occlusal points were associated with any outcome. Our findings do not provide evidence to support a relationship between prenatal exposure to Hg⁰ from maternal dental amalgam and neurodevelopmental outcomes in children at 5 years of age.

  3. Effect of dental amalgam on gene expression profiles in rat cerebrum, cerebellum, liver and kidney.

    PubMed

    Takahashi, Yoshifumi; Tsuruta, Shozo; Honda, Akiko; Fujiwara, Yasuyuki; Satoh, Masahiko; Yasutake, Akira

    2012-01-01

    Dental amalgam is a source of exposure to elemental mercury vapor in the general population. The aim of this study was to elucidate the effect of elemental mercury vapor exposure from dental amalgam restorations on gene expression profiles. Out of 26,962 rat genes, mercury vapor was found to increase the expression of 1 gene (Atp1b3) and decrease the expression of 1 gene (Tap1) in the cerebrum, increase the expression of 1 gene (Dnaja2) in the cerebellum, increase the expression of 2 genes (Actb and Timm23) and decrease the expression of 1 gene (Spink3) in the liver, increase the expression of 2 genes (RT1-Bb and Mgat5) and decrease the expression of 6 genes (Tnfaip8, Rara, Slc2a4, Wdr12, Pias4 and Timm13) in the kidney.

  4. Element sensitive X-ray micro tomography for determination of the metal diffusion in teeth with amalgam fillings

    NASA Astrophysics Data System (ADS)

    Masschaele, B.; Baechler, S.; Cauwels, P.; Cloetens, P.; Dierick, M.; Jolie, J.; Mondelaers, W.

    2001-06-01

    Element sensitive X-ray tomography has been applied to detect the metal diffusion from the amalgam tooth filling into the tooth. By performing tomographies with energies above and below the K-edges of the various metals of the amalgam, it is possible to determine their distribution. Here presented are the results of measurements at ID15 and ID19 of the ESRF. To improve the sensitivity of our measurements a method for contrast enhancement for projections was developed.

  5. Legislation and informed consent brochures for dental patients receiving amalgam restorations.

    PubMed

    Edlich, Richard F; Cochran, Amy A; Cross, Catherine L; Wack, Courtney A; Long, William B; Newkirk, Anthony T

    2008-01-01

    In 2008, Norway banned the use of mercury for amalgam restorations. Four states in the United States have developed Informed Consent Brochures for amalgam restorations that must be given to their dental patients. The authors describe a patient who had a large cavity in his left lower molar tooth no.18 that had to be removed by an oral surgeon. When the patient went to the oral surgeon, the surgeon told the patient that he would replace the carious tooth with a gold implant. He was not given an Informed Consent Brochure regarding dental restorative materials. The oral surgeon extracted the carious tooth, replacing the tooth with a supposed gold crown implant. On his yearly dental examination, his dentist took an x-ray of his dental implant and explained that the x-ray could not distinguish whether the implant contained either gold or mercury. Consequently, the dentist referred him to a dental clinic in which the dental implant could be removed without mercury contamination of the patient's neurologic system during the extraction of the implant from the root canal. During the removal of the dental restoration, the dentist found build up expanding into the root canal that had a black color. The crown and underlying tooth were sent to ALT BioScience for analysis. Elemental analysis of the crown and underlying tooth confirmed the presence of mercury in the restoration. The patient should have been given an Informed Consent Brochure by the dentist that described the dental restoration that was used in the dental implant.

  6. Comparison of chlorine and chloramine in the release of mercury from dental amalgam.

    PubMed

    Stone, Mark E; Scott, John W; Schultz, Stephen T; Berry, Denise L; Wilcoxon, Monte; Piwoni, Marv; Panno, Brent; Bordson, Gary

    2009-01-01

    The purpose of this project was to compare the ability of chlorine (HOCl/OCl(-)) and monochloramine (NH(2)Cl) to mobilize mercury from dental amalgam. Two types of amalgam were used in this investigation: laboratory-prepared amalgam and samples obtained from dental-unit wastewater. For disinfectant exposure simulations, 0.5 g of either the laboratory-generated or clinically obtained amalgam waste was added to 250 mL amber bottles. The amalgam samples were agitated by end-over-end rotation at 30 rpm in the presence of 1 mg/L chlorine, 10 mg/L chlorine, 1 mg/L monochloramine, 10 mg/L monochloramine, or deionized water for intervals of 0 h, 2 h, 4 h, 8 h, and 24 h for the clinically obtained amalgam waste samples and 4 h and 24 h for the laboratory-prepared samples. Chlorine and monochloramine concentrations were measured with a spectrophotometer. Samples were filtered through a 0.45 microm membrane filter and analyzed for mercury with USEPA standard method 245.7. When the two sample types were combined, the mean mercury level in the 1 mg/L chlorine group was 0.020 mg/L (n=25, SD=0.008). The 10 mg/L chlorine group had a mean mercury concentration of 0.59 mg/L (n=25, SD=1.06). The 1 mg/L chloramine group had a mean mercury level of 0.023 mg/L (n=25, SD=0.010). The 10 mg/L chloramine group had a mean mercury level of 0.024 mg/L (n=25, SD=0.011). Independent samples t-tests showed that there was a significant difference between the natural log mercury measurements of 10 mg/L chlorine compared to those of 1 mg/L and 10 mg/L chloramine. Changing from chlorine to chloramine disinfection at water treatment plants would not be expected to produce substantial increases in dissolved mercury levels in dental-unit wastewater.

  7. Cerebrospinal fluid protein changes in multiple sclerosis after dental amalgam removal.

    PubMed

    Huggins, H A; Levy, T E

    1998-08-01

    A relationship between multiple sclerosis (MS) and dental silver-mercury fillings has been suggested by some investigators, but never proven. This study documents objective biochemical changes following the removal of these fillings along with other dental materials, utilizing a new health care model of multidisciplinary planning and treatment. The dramatic changes in photolabeling of cerebrospinal fluid (CSF) proteins following these dental interventions suggest CSF photolabeling may serve as an objective biomarker for monitoring MS. The clear-cut character of these changes should also encourage more research to better define this possible association between dental mercury and MS.

  8. Theoretical models of mercury dissolution from dental amalgams in neutral and acidic flows

    NASA Astrophysics Data System (ADS)

    Keanini, Russell G.; Ferracane, Jack L.; Okabe, Toru

    2001-06-01

    This article reports an experimental and theoretical investigation of mercury dissolution from dental amalgams immersed in neutral (noncorrosive) and acidic (corrosive) flows. Atomic absorption spectrophotometric measurements of Hg loss indicate that in neutral flow, surface oxide films formed in air prior to immersion persist and effectively suppress significant mercury release. In acidic (pH 1) flows, by contrast, oxide films are unstable and dissolve; depending on the amalgam’s material composition, particularly its copper content, two distinct mercury release mechanisms are initiated. In low copper amalgam, high initial mercury release rates are observed and appear to reflect preferential mercury dissolution from unstable Sn8Hg ( γ 2) grains within the amalgam matrix. In high copper amalgam, mercury release rates are initially low, but increase with time. Microscopic examination suggests that this feature reflects corrosion of copper from grains of Cu6Sn5 ( η') and consequent exposure of Ag2Hg3 ( γ 1) grains; the latter serve as internal mercury release sites and become more numerous as corrosion proceeds. Three theoretical models are proposed in order to explain observed dissolution characteristics. Model I, applicable to high and low copper amalgams in neutral flow, assumes that mercury dissolution is mediated by solid diffusion within the amalgam, and that a thin oxide film persists on the amalgam’s surface and lumps diffusive in-film transport into an effective convective boundary condition. Model II, applicable to low copper amalgam in acidic flow, assumes that the amalgam’s external oxide film dissolves on a short time scale relative to the experimental observation period; it neglects corrosive suppression of mercury transport. Model III, applicable to high copper amalgam in acidic flow, assumes that internal mercury release sites are created by corrosion of copper in η' grains and that corrosion proceeds via an oxidation-reduction reaction

  9. The Microfloral Analysis of Secondary Caries Biofilm around Class I and Class II Composite and Amalgam Fillings

    PubMed Central

    2010-01-01

    Background Secondary caries is responsible for 60 percent of all replacement restorations in the typical dental practice. The diversity of the bacterial sources and the different types of filling materials could play a role in secondary caries. The aim of this study was to determine and compare the microbial spectrum of secondary caries biofilms around amalgam and composite resin restorations. Methods Clinical samples were collected from freshly extracted teeth diagnosed with clinical secondary caries. Samples were categorized into four groups according to the types of restoration materials and the classification of the cavity. Biofilms were harvested from the tooth-restoration interface using a dental explorer and after dilution were incubated on special agars. The bacteria were identified using the biochemical appraisal system. Statistical calculations were carried out using SPSS11.5 software to analyze the prevalence of the bacteria involved in secondary caries. Results Samples from a total of four groups were collected: two groups were collected from amalgam restorations, each had 21 samples from both Class I and Class II caries; and the other two groups were from composite resin restorations, each had 13 samples from both class I and class II caries. Our results showed: (1) Anaerobic species were dominant in both restoration materials. (2) In terms of the types of individual bacteria, no significant differences were found among the four groups according to the geometric mean of the detected bacteria (P > 0.05). However, there were significant differences among the detected bacteria within each group (P < 0.05). The composition of each bacterium had no statistical difference among the four groups (P > 0.05), but showed significant differences among the detected bacteria in each group (P < 0.05). (3) Among the four groups, there were no significant differences for the detection rate of each bacterium (P > 0.05), however, the detection rate of each bacterium

  10. The use of amalgam powder and calcium hydroxide to recreate a radiopaque image of a lost dental restoration.

    PubMed

    Shiroma, Calvin Y

    2002-05-01

    Radiographs of dental restorations are highly reliable when used to identify postmortem dental remains. A problem exists if key dental restorations are missing or defective, which results in the loss of a comparative radiographic image. This article describes a simple method allowing the odontologist to quickly recreate a temporary radiopaque restoration. This article presents a method of using amalgam powder (radiopaque material) and calcium hydroxide (radiopaque material and transport medium for the amalgam powder) to recreate a radiopaque image on a tooth that has lost a dental restoration. Amalgam powder and calcium hydroxide is easily obtained (in any dental office), fairly clean, easy to manipulate, inexpensive, inert, stable, and able to be removed without damaging the dental remains. The amalgam powder/calcium hydroxide mixture can easily be re-shaped or modified to reflect the radiopaque image of the original restoration. Radiographic comparison of the "restored" dental remains to the antemortem radiographs is now possible. The use of this technique is presented in a case report. PMID:12051346

  11. The use of amalgam powder and calcium hydroxide to recreate a radiopaque image of a lost dental restoration.

    PubMed

    Shiroma, Calvin Y

    2002-05-01

    Radiographs of dental restorations are highly reliable when used to identify postmortem dental remains. A problem exists if key dental restorations are missing or defective, which results in the loss of a comparative radiographic image. This article describes a simple method allowing the odontologist to quickly recreate a temporary radiopaque restoration. This article presents a method of using amalgam powder (radiopaque material) and calcium hydroxide (radiopaque material and transport medium for the amalgam powder) to recreate a radiopaque image on a tooth that has lost a dental restoration. Amalgam powder and calcium hydroxide is easily obtained (in any dental office), fairly clean, easy to manipulate, inexpensive, inert, stable, and able to be removed without damaging the dental remains. The amalgam powder/calcium hydroxide mixture can easily be re-shaped or modified to reflect the radiopaque image of the original restoration. Radiographic comparison of the "restored" dental remains to the antemortem radiographs is now possible. The use of this technique is presented in a case report.

  12. Dental metal-induced innate reactivity in keratinocytes.

    PubMed

    Mortazavi, S M J; Mortazavi, Ghazal; Paknahad, Maryam

    2016-06-01

    In their paper that is published in Toxicology in Vitro, Rachmawati et al. have recently claimed that in spite of the growing concern about the safety of amalgam, negative reports about the health effects of dental amalgam are still scarce or controversial. Substantial evidence indicates that mercury release from dental amalgam fillings may adversely affect human health. Over the past years, we have shown that exposure to electromagnetic fields (EMFs) can increase the release of mercury from dental amalgam fillings. It is worth mentioning that the results of investigations on the microleakage of amalgam fillings following MRI have confirmed our results. Furthermore, exposure to X-rays as a part of the electromagnetic spectrum has also been linked to increased mercury release from dental amalgam fillings. Considering the explosive rise in human exposure to electromagnetic fields, the role of human exposure to EMF as a key factor in increasing the release of mercury from dental amalgam restorations cannot be simply ignored. PMID:26928047

  13. In vitro lymphoproliferative assays with HgCl2 cannot identify patients with systemic symptoms attributed to dental amalgam.

    PubMed

    Cederbrant, K; Gunnarsson, L G; Hultman, P; Norda, R; Tibbling-Grahn, L

    1999-08-01

    Dental amalgam is suspected, by some exposed individuals, to cause various systemic psychological, sensory, and neurological symptoms. Since not all amalgam-bearers experience such reactions, an individual characteristic--for example, a susceptible immune system--might explain these conditions. In vitro lymphocyte proliferation is a valuable tool in the diagnosis of allergy. With HgCl2 as the antigen, however, the test is hampered, because Hg2+ can cause unspecific lymphocyte proliferation, optimal at 1.4 to 9.5 micrograms HgCl2/mL. Recently, the use of suboptimal HgCl2 concentrations (< or = 0.5 microgram/mL) has been suggested to circumvent these problems. The main aim of this study was to investigate whether patients with systemic symptoms alleged to result from the presence of dental amalgam differ from healthy controls, with reference to in vitro lymphoproliferative responses to HgCl2 < or = 0.5 microgram/mL. Three different test protocols--lymphocyte transformation test (LTT) in micro- and macro-cultures, and the memory lymphocyte immunostimulation assay (MELISA)--were used. Other immune parameters--such as a standard patch test for dental materials, the number of T- and B-lymphocytes, monocytes, granulocytes, and NK cells in peripheral blood, allergic symptoms, and predisposition--were also investigated. Twenty-three amalgam patients, 30 healthy blood donors with amalgam, ten healthy subjects without amalgam, and nine patients with oral lichen planus (OLP) adjacent to dental amalgam and a positive patch test to Hg0 were tested. None of the investigated immune parameters revealed any significant differences between amalgam patients and controls. The sensitivity of in vitro lymphocyte proliferation ranged from 33 to 67%, with the OLP patients as a positive control group, and the specificity from 0 to 70% for healthy controls with a negative patch test to Hg0. Thus, despite the use of HgCl2 < or = 0.5 microgram/mL, a high frequency of positive results was

  14. The effects of the Nd:YAG laser on amalgam dental restorative material.

    PubMed

    Cernavin, I; Hogan, S P

    1999-06-01

    The Nd:YAG laser has been marketed as an instrument for use on both hard and soft dental tissues. Its potential for use on hard tissues is limited but it may be the instrument of choice for use in certain soft tissue procedures. The aim of this study was to examine the effects of the Nd:YAG laser on amalgam restorations which are frequently placed on tooth surfaces adjacent to areas of soft tissue which may be subjected to the laser. The amalgam used was Tytin. The laser firing was controlled by a computer and a constant repetition rate of 40 Hz was used. Energy per pulse was altered as follows: 30 mJ, 40 mJ, 60 mJ, 80 mJ, 120 mJ and 140 mJ. Exposure times of 0.05 s (2 pulses), 0.125 s (5 pulses), 0.25 s (10 pulses), 0.5 s (20 pulses), 1 s (40 pulses), 2 s (80 pulses), 3 s (120 pulses), 4 s (160 pulses), and 5 s (200 pulses) were used. The width of defect was measured using a measuring microscope with 10x magnification and it was established that the damage threshold lies between 0.125 s (5 pulses) and 0.25 s (10 pulses) for 30 mJ per pulse. Scanning electron microscope observations revealed that the melting of amalgam at exposure times of 5 s actually decreased the size of the observed defect. The data were analysed using a two-way ANOVA statistical test. There was a significant (p < 0.001) correlation between the width of the defect and exposure time up to an exposure time of 4 s and the width of defect and the energy per pulse setting. The findings indicate that amalgam restorations are damaged by inadvertent laser exposure and clinicians must take measures to protect such restorations during lasing of soft tissues.

  15. Clinical Evaluation of Reasons for Replacement of Amalgam Restorations in Patients Referring to a Dental School in Iran

    PubMed Central

    Pouralibaba, Firoz; Joulaei, Mohammad; Kashefimehr, Atabak; Pakdel, Farzaneh; Jamali, Zahra; Esmaeili, Ali

    2010-01-01

    Background and aims The present study evaluated the most common reasons for replacing amalgam restorations in a university clinic. Materials and methods A total of 217 restorations which needed to be replaced were clinically and radiographically evaluated in a period of 4 months. The frequencies of reasons for replacing amalgam restorations were calculated: The assessed items included recurrent caries, tooth structure fracture (functional or non-functional cusps), amalgam bulk fracture, amalgam marginal fracture, proximal overhangs, and esthetics. Data were analyzed using Fischer’s exact test. Results Both in vital teeth and teeth which had undergone root canal therapy, the most common reason for amalgam replacement was cusp fracture, with the fracture of non-functional cusps being statistically significant. Recurrent caries was the second most common reason for amalgam replacement. In Class I restorations, the most common reasons were recurrent caries and esthetics, with no statistical significance. The most frequent problem in Class II restorations was fracture of non-functional cusps, with a statistical significance in three-surface restorations. Conclusion According to the results, failing to reduce undermined cusps and neglectful caries removal are the reasons for majority of amalgam restoration replacements. These issues should be emphasized in the curriculum for dental students and continuing education courses. PMID:22991598

  16. Effects of mercury release from amalgam dental restorations during cremation on soil mercury levels of three New Zealand crematoria

    SciTech Connect

    Nieschmidt, A.K.; Kim, N.D.

    1997-05-01

    A vast amount of research has been undertaken in the last 15-20 years on the corrosion reactions occurring in dental amalgam, release of mercury from amalgam restorations, and the toxic effects of this released mercury on the human body. However, one environmental aspect of amalgam dental restorations that has not received a great deal of attention is the release of mercury during cremation. Mercury is liberated during cremation both because dental amalgams are unstable at cremation temperatures (650-700{degrees}C) and because the free mercury metal is highly volatile. In New Zealand, 58% of deaths are followed by cremation and this figure is likely to rise in the future. This increasing use of cremation as the method of corpse disposal, coupled with the fact that each amalgam restoration is approximately 50% mercury, implies that a significant amount of mercury may be emitted into the environment every year. This study examines mercury released from crematoria in New Zealand. 20 refs., 2 figs., 5 tabs.

  17. In vitro fabrication of dental filling nanopowder by green route and its antibacterial activity against dental pathogens.

    PubMed

    Lee, Jeong-Ho; Velmurugan, Palanivel; Park, Jung-Hee; Lee, Kui-Jae; Jin, Jong-Sik; Park, Yool-Jin; Bang, Keuk-Soo; Oh, Byung-Taek

    2016-06-01

    The aim of this study was to introduce novel Sn, Cu, Hg, and Ag nanopowders (NPs) and a composite nanopowder (NP) synthesized using Salvia miltiorrhiza Bunge (SM) root extract as a reducing and capping agent to improve the antibacterial property of dental filling materials. All of the NPs obtained were characterized using a scanning transmission electron microscope (STEM), and energy dispersive X-ray (EDX) spectrum imaging was performed to map the elemental distributions of the NP composite. Fourier transform infrared (FTIR) spectroscopy was performed to identify the role of various functional groups in all of the obtained NPs and the phyto-compound responsible for the reduction of various metal ions. The X-ray diffraction (XRD) patterns clearly illustrated the crystalline phase of the synthesized NP. The antibacterial properties of the synthesized Sn, Cu, Hg, Ag, composite NP, SM root extract, and commercial amalgam powder were evaluated. The Cu, composite NP, SM root extract and Ag NP displayed excellent antibacterial activity against dental bacteria Streptococcus mutans and Lactobacillus acidophilus. The results of this study require further evaluation for signs of metal toxicity in appropriate animal models. However, the results are encouraging for the application of metal NPs as suitable alternatives for antibiotics and disinfectants, especially in dental filling materials. PMID:27085055

  18. Cytogenetic genotoxic investigation in peripheral blood lymphocytes of subjects with dental composite restorative filling materials.

    PubMed

    Pettini, F; Savino, M; Corsalini, M; Cantore, S; Ballini, A

    2015-01-01

    Dental composite resins are biomaterials commonly used to aesthetically restore the structure and function of teeth impaired by caries, erosion, or fracture. Residual monomers released from resin restorations as a result of incomplete polymerization processes interact with living oral tissues. The objective of this study was to evaluate the genotoxicity of a common dental composite material (Enamel Plus-HFO), in subjects with average 13 filled teeth with the same material, compared to a control group (subjects having neither amalgam nor composite resin fillings). Genotoxicity assessment of composite materials was carried out in vitro in human peripheral blood leukocytes using sister-chromatid exchange (SCE) and chromosomal aberrations (CA) cytogenetic tests. The results of correlation and multiple regression analyses confirmed the absence of a relationship between SCE/cell, high frequency of SCE(HFC) or CA frequencies and exposure to dental composite materials. These results indicate that composite resins used for dental restorations differ extensively in vivo in their cytotoxic and genotoxic potential and in their ability to affect chromosomal integrity, cell-cycle progression, DNA replication and repair. PMID:25864763

  19. Cytogenetic genotoxic investigation in peripheral blood lymphocytes of subjects with dental composite restorative filling materials.

    PubMed

    Pettini, F; Savino, M; Corsalini, M; Cantore, S; Ballini, A

    2015-01-01

    Dental composite resins are biomaterials commonly used to aesthetically restore the structure and function of teeth impaired by caries, erosion, or fracture. Residual monomers released from resin restorations as a result of incomplete polymerization processes interact with living oral tissues. The objective of this study was to evaluate the genotoxicity of a common dental composite material (Enamel Plus-HFO), in subjects with average 13 filled teeth with the same material, compared to a control group (subjects having neither amalgam nor composite resin fillings). Genotoxicity assessment of composite materials was carried out in vitro in human peripheral blood leukocytes using sister-chromatid exchange (SCE) and chromosomal aberrations (CA) cytogenetic tests. The results of correlation and multiple regression analyses confirmed the absence of a relationship between SCE/cell, high frequency of SCE(HFC) or CA frequencies and exposure to dental composite materials. These results indicate that composite resins used for dental restorations differ extensively in vivo in their cytotoxic and genotoxic potential and in their ability to affect chromosomal integrity, cell-cycle progression, DNA replication and repair.

  20. Effects of the Nd:YAG laser on amalgam dental restorative material: a preliminary study

    NASA Astrophysics Data System (ADS)

    Cernavin, Igor; Hogan, Sean P.

    1996-09-01

    The Nd:YAG laser has been marketed as an instrument for use on both hard and soft dental tissues. Its potential for use on hard tissues is limited but it may be the instrument of choice for use in certain soft tissue procedures. The aim of this study was to examine the effects of the Nd:YAG laser on amalgam restorations which frequently occur on tooth surfaces adjacent to areas of soft tissue which may be subjected to the laser. The amalgam used was Tytin. The laser firing was controlled by a computer and a constant repetition rate of 40 Hz was used. Energy per pulse was altered as follows, 30 mJ, 40 mJ, 60 mJ, 80 mJ, 120 mJ and 140 mJ. Exposure times of 0.05 sec, 0.125 sec, 0.25 sec, 0.5 sec, 1 sec, 2 sec, 3 sec, 4 sec, and 5 sec were used. The width of defect was measured using a Nikon measurescope with 10x magnification and it was established that the damage threshold lies between 0.125 sec and 0.25 sec for 30 mJ per pulse. The data was analyzed using a one way ANOVA statistical test. There was a significant correlation between the width of the defect and energy per pulse setting as well as exposure time. The findings indicate that amalgam restorations are prone to damage from inadvertent laser exposure and clinicians must take measures to protect such restorations during lasing of soft tissues.

  1. Qualitative Analysis of Teeth and Evaluation of Amalgam Elements Penetration into Dental Matrix Using Laser Induced Breakdown Spectroscopy

    PubMed Central

    Gazmeh, Meisam; Bahreini, Maryam; Tavassoli, Seyed Hassan; Asnaashari, Mohammad

    2015-01-01

    Introduction: In this study, laser induced breakdown spectroscopy (LIBS) is used for qualitative analysis of healthy and carious teeth. The technique of laser ablation is receiving increasing attention for applications in dentistry, specifically for the treatment of teeth such as drilling of micro-holes and plaque removal. Methods: A quality-switched (Q-switched) Neodymium-Doped Yttrium Aluminium Garnet (Nd:YAG) laser operating at wavelength of 1064 nm, pulse energy of 90 mJ/pulse, repetition rate of 2Hz and pulse duration of 6 ns was used in this analysis. In the process of ablation a luminous micro-plasma is normally generated which may be exploited for on-line elemental analysis via laser induced breakdown spectroscopy technique. We propose laser induced breakdown spectroscopy as a rapid, in situ and easy method for monitoring drilling process. Results: The results of elemental analysis show the presence of some trace elements in teeth including P, Ca, Mg, Zn, K, Sr, C, Na, H, O and the permeability of some amalgam (teeth filling materials) elements including Hg, Ag, Cu and Sn into dental matrix. Conclusion: This study addresses the ability of LIBS in elemental analysis of teeth and its feasibility in acute identification of healthy and carious teeth during drilling process for future clinical applications. PMID:25987971

  2. Potential public health risks related to mercury/amalgam discharge from dental offices.

    PubMed

    Rowe, N H; Sidhu, K S; Chadzynski, L; Babcock, R F

    1996-02-01

    Mercury is a toxic and bioaccumulative metal. It exists in elemental, inorganic and organic forms. The use of mercury by the dental profession represents approximately 6 percent of the total annual domestic consumption and is estimated to contribute significantly to the discharge of mercury (14 percent in one study) to waste-water streams. Publicly owned treatment works (POTW) must obtain and comply with a National Pollutant Discharge Elimination System waste-water discharge permit. When minimal mercury discharge limits into surface waters are exceeded, an upstream search for contributors of mercury to the waste stream may result. Given the present sociopolitical environment, mercury discharge from dental offices will increasingly receive scrutiny. Strategies to minimize discharge of mercury/amalgam waste include engineering controls such as changes in the discharge process, changes in the composition of commercial products, and changes in control equipment. Governmental strategies include an outright ban, the setting of discharge standards, and educational efforts. Study of these strategies with evaluation of effectiveness is needed. PMID:9520646

  3. The failure of amalgam dental restorations due to cyclic fatigue crack growth.

    PubMed

    Arola, D; Huang, M P; Sultan, M B

    1999-06-01

    In this study a restored mandibular molar with different Class II amalgam preparations was examined to analyze the potential for restoration failure attributed to cyclic fatigue crack growth. A finite element analysis was used to determine the stress distribution along the cavo-surface margin which results from occlusal loading of each restoration. The cyclic crack growth rate of sub-surface flaws located along the dentinal cavo-surface margin were determined utilizing the Paris law. Based on similarities in material properties and lack of fatigue property data for dental biomaterials, the cyclic fatigue crack growth parameters for engineering ceramics were used to approximate the crack growth behavior. It was found that flaws located within the dentine along the buccal and lingual margins can significantly reduce the fatigue life of restored teeth. Sub-surface cracks as short as 25 microm were found capable of promoting tooth fracture well within 25 years from the time of restoration. Furthermore, cracks longer than 100 microm reduced the fatigue life to less than 5 years. Consequently, sub-surface cracks introduced during cavity preparation with conventional dental burrs may serve as a principal source for premature restoration failure.

  4. Hg, Bi, Cu and Zn distribution in human teeth treated by dental amalgam measured by synchrotron microprobe

    NASA Astrophysics Data System (ADS)

    Carvalho, M. L.; Marques, J. P.; Brito, J.; Casaca, C.; Cunha, A. S.

    2002-11-01

    Human teeth restored with dental amalgam were analysed by a synchrotron microprobe to evaluate the diffusion of its major constituents, Cu, Zn and Hg, throughout the tooth structures. We measured the elemental distribution inside the tooth from the root to the enamel, specially the region around the amalgam, after its total removal. Hg is present only in restored teeth and concentration profiles show strongly increased levels of this element close to the amalgam region, reaching 500 μg g -1 in one or two cases, decreasing strongly to the inner part of the tooth. Pb concentration profiles do not seem to be affected by metallic amalgam. Very high concentrations of Bi were found in one of the restored teeth, reaching more than 2000 μg g -1, decreasing sharply to the outer regions. The distribution of Mn, Fe, Cu and Zn was also determined in order to evaluate elemental influences by amalgam components. No significant changes in elemental concentrations were detected for Mn and Fe between healthy and restored teeth. However, the levels of Zn and Cu are increased in restored teeth. An X-ray fluorescence set-up with microprobe capabilities, 100 μm of spatial resolution and an energy of 18 keV, installed at LURE synchrotron (France) was used.

  5. Does amalgam affect the immune system? A controversial issue.

    PubMed

    Eneström, S; Hultman, P

    1995-03-01

    Although in use for more than 150 years, dental amalgam has been questioned more or less vigorously as a dental restoration material due to its alleged health hazard. Humans are exposed to mercury and the other main dental amalgam metals (Ag, Sn, Cu, Zn) via vapour, corrosion products in swallowed saliva, and direct absorption into the blood from the oral cavity. Dental amalgam fillings are the most important source of mercury exposure in the general population. Local, and in some instances, systemic hypersensitivity reactions to dental amalgam metals, especially mercury, occur at a low frequency among amalgam bearers. Experimental and clinical data strongly indicate that these and other subclinical systemic adverse immunological reactions to dental amalgam metals in humans will be linked to certain MHC genotypes, and affect only a small number of the exposed individuals. These individuals will be very difficult to detect in a mixed population of susceptible and resistant individuals, including persons with alleged symptoms due to dental amalgam fillings, where many of the individuals are likely to suffer from conditions with no proven immunological background such as multiple chemical sensitivity syndrome. Intensified studies should be performed to identify such susceptible MHC genotypes, taking advantage of the reported cases of more heavily metal-exposed humans with systemic autoimmune reactions. Further studies will also be needed to ascertain whether the combined exposure to the metals in dental amalgam may lower the threshold for adverse immunological reactions, since recent studies have shown that the metals in alloy, especially silver, may induce autoimmunity in genetically susceptible mice.

  6. Curriculum time compared to clinical procedures in amalgam and composite posterior restorations in U.S. dental schools: a preliminary study.

    PubMed

    Rey, Rosalia; Nimmo, Susan; Childs, Gail S; Behar-Horenstein, Linda S

    2015-03-01

    Dental clinicians have an expanding range of biomaterial choices for restoring tooth structure. Scientific developments in cariology, advances in dental biomaterials, and patients' esthetic concerns have led to a reduction in amalgam restorations and an increase in composite restorations. The aim of this study was to compare teaching time with students' clinical procedures in amalgam and composite posterior restorations in dental schools across the United States. Academic deans in 60 schools were invited to complete a survey that asked for the amount of instructional time for amalgam and composite posterior restorations and the number of clinical restorations performed by their Classes of 2009, 2010, and 2011. Of these 60, 12 returned surveys with complete data, for a 20% response rate. Responses from these schools showed little change in lecture and preclinical laboratory instruction from 2009 to 2011. There was a slight increase in two-surface restorations for both amalgam and composites; however, the total number of reported composite and amalgam restorations remained the same. Of 204,864 restorations reported, 53% were composite, and 47% were amalgam. There were twice as many multisurface large or complex amalgam restorations as composites. One-surface composite restorations exceeded amalgams. Among the participating schools, there was little to no change between curriculum time and clinical procedures. Findings from this preliminary study reflect a modest increase in two-surface resin-based restorations placed by dental students from 2009 to 2011 and little change in curricular time devoted to teaching amalgam restorations. The total number of posterior composite restorations placed by students in these schools was slightly higher than amalgams.

  7. Curriculum time compared to clinical procedures in amalgam and composite posterior restorations in U.S. dental schools: a preliminary study.

    PubMed

    Rey, Rosalia; Nimmo, Susan; Childs, Gail S; Behar-Horenstein, Linda S

    2015-03-01

    Dental clinicians have an expanding range of biomaterial choices for restoring tooth structure. Scientific developments in cariology, advances in dental biomaterials, and patients' esthetic concerns have led to a reduction in amalgam restorations and an increase in composite restorations. The aim of this study was to compare teaching time with students' clinical procedures in amalgam and composite posterior restorations in dental schools across the United States. Academic deans in 60 schools were invited to complete a survey that asked for the amount of instructional time for amalgam and composite posterior restorations and the number of clinical restorations performed by their Classes of 2009, 2010, and 2011. Of these 60, 12 returned surveys with complete data, for a 20% response rate. Responses from these schools showed little change in lecture and preclinical laboratory instruction from 2009 to 2011. There was a slight increase in two-surface restorations for both amalgam and composites; however, the total number of reported composite and amalgam restorations remained the same. Of 204,864 restorations reported, 53% were composite, and 47% were amalgam. There were twice as many multisurface large or complex amalgam restorations as composites. One-surface composite restorations exceeded amalgams. Among the participating schools, there was little to no change between curriculum time and clinical procedures. Findings from this preliminary study reflect a modest increase in two-surface resin-based restorations placed by dental students from 2009 to 2011 and little change in curricular time devoted to teaching amalgam restorations. The total number of posterior composite restorations placed by students in these schools was slightly higher than amalgams. PMID:25729027

  8. A dental cloud over a silver filling

    SciTech Connect

    Van Pelt, D.

    1990-10-01

    For 150 years, silver fillings have been used for cavities. Now some dentists are urging their colleagues to stop using the mixture because it includes mercury, which they say poses health risks. While a small group of dentists have complied, the mainstream profession says the claims are unsubstantiated.

  9. Magnetic field effects on dental amalgam in divers welding and cutting electrically underwater

    SciTech Connect

    Ortendahl, T.W.; Hoegstedt, P.

    1988-11-01

    Divers have for some years been complaining about a metallic taste in the mouth while electrically welding and cutting underwater. This paper reports on results from an assessment of this problem. It was hypothesized that the magnetic fields arising from the welding or cutting current could correlate with the reported symptoms. The intraoral magnetic flux density was calculated to 1.15 mT, at 650 ADC, in a normal cutting situation. This was verified in vivo. This magnetic field was shown to contain an AC component that is a candidate for inducing secondary currents in the oral tissues and restorative materials. Five submerged divers exposed to a magnetic field of 0.35 mT did not report any metallic taste. Magnetophosphenes were reported by 1 diver. (Magnetophosphenes are luminous impressions due to excitement of the retina by a magnetic field in addition to or in place of impingement of light rays.) Only a slight shielding effect to magnetic fields was observed due to a copper-brass helmet. An in vitro model for exposure of dental amalgams to magnetic fields was designed. Recommendations for decreasing the magnetic field surrounding the diver in practical work is given.

  10. Beeswax as dental filling on a neolithic human tooth.

    PubMed

    Bernardini, Federico; Tuniz, Claudio; Coppa, Alfredo; Mancini, Lucia; Dreossi, Diego; Eichert, Diane; Turco, Gianluca; Biasotto, Matteo; Terrasi, Filippo; De Cesare, Nicola; Hua, Quan; Levchenko, Vladimir

    2012-01-01

    Evidence of prehistoric dentistry has been limited to a few cases, the most ancient dating back to the Neolithic. Here we report a 6500-year-old human mandible from Slovenia whose left canine crown bears the traces of a filling with beeswax. The use of different analytical techniques, including synchrotron radiation computed micro-tomography (micro-CT), Accelerator Mass Spectrometry (AMS) radiocarbon dating, Infrared (IR) Spectroscopy and Scanning Electron Microscopy (SEM), has shown that the exposed area of dentine resulting from occlusal wear and the upper part of a vertical crack affecting enamel and dentin tissues were filled with beeswax shortly before or after the individual's death. If the filling was done when the person was still alive, the intervention was likely aimed to relieve tooth sensitivity derived from either exposed dentine and/or the pain resulting from chewing on a cracked tooth: this would provide the earliest known direct evidence of therapeutic-palliative dental filling.

  11. British Society of Prosthodontics Debate on the Implications of the Minamata Convention on Mercury to Dental Amalgam--Should our Patients be Worried?.

    PubMed

    Austin, Rupert; Eliyas, Shiyana; Burke, F J Trevor; Taylor, Phil; Toner, James; Briggs, Peter

    2016-01-01

    In 2013, the Minamata Convention on Mercury called for a global phase-down of amalgam use, with a view to reduce environmental mercury pollution. This will significantly impact UK dentistry, given the still extensive use of amalgam in U.K. general dental practice. However, until now there has been little national discussion or debate. In Spring 2015, The British Society of Prosthodontics dedicated a significant part of its Annual Conference to debating the implications of this issue. Clinical case examples were discussed with audience interaction and voting facilitated using innovative Audience Response System Technology. A remarkable range of concerns and opinions were given. The debate elicited specific concerns amongst clinicians regarding the suitability of mercury-free alternatives to amalgam; particularly where cavities are large and extend beneath the gingival anatomy. There are also anecdotal reports of Dental Foundation (DF) dentists not being adequately taught the use of dental amalgam in undergraduate dental schools. CPD/CLINICAL RELEVANCE: Many clinicians, especially those treating patients for whom moisture control is challenging, feel that amalgam should remain available for clinicians to choose in certain clinical circumstances for the restoration of posterior teeth, even in the event of a complete phase-down.

  12. British Society of Prosthodontics Debate on the Implications of the Minamata Convention on Mercury to Dental Amalgam--Should our Patients be Worried?.

    PubMed

    Austin, Rupert; Eliyas, Shiyana; Burke, F J Trevor; Taylor, Phil; Toner, James; Briggs, Peter

    2016-01-01

    In 2013, the Minamata Convention on Mercury called for a global phase-down of amalgam use, with a view to reduce environmental mercury pollution. This will significantly impact UK dentistry, given the still extensive use of amalgam in U.K. general dental practice. However, until now there has been little national discussion or debate. In Spring 2015, The British Society of Prosthodontics dedicated a significant part of its Annual Conference to debating the implications of this issue. Clinical case examples were discussed with audience interaction and voting facilitated using innovative Audience Response System Technology. A remarkable range of concerns and opinions were given. The debate elicited specific concerns amongst clinicians regarding the suitability of mercury-free alternatives to amalgam; particularly where cavities are large and extend beneath the gingival anatomy. There are also anecdotal reports of Dental Foundation (DF) dentists not being adequately taught the use of dental amalgam in undergraduate dental schools. CPD/CLINICAL RELEVANCE: Many clinicians, especially those treating patients for whom moisture control is challenging, feel that amalgam should remain available for clinicians to choose in certain clinical circumstances for the restoration of posterior teeth, even in the event of a complete phase-down. PMID:27024898

  13. Effects of In-Office and Home Bleaching Gels on the Surface Mercury Levels of Dental Amalgam

    PubMed Central

    Oskoee, Parnian Alizadeh; Kahnamoui, Mahdi Abed; Oskoee, Siavash Savadi; Zadfattah, Firooz; Pournaghi-Azar, Fatemeh

    2010-01-01

    Objectives: The aim of this study was to evaluate the effect of different in-office and home bleaching gels on the surface mercury levels of dental amalgam. Methods: Sixty disk-shaped amalgam specimens (GS-80, SDI- Australia) were prepared and randomly divided into the following treatment groups: 1. Distilled water (control); 2. 15% home-bleach carbamide peroxide (Opalescence PF, Ultra dent, USA) applied for 6 h/day for 3 weeks; and 3. 35% in-office bleach carbamide peroxide (Opalescence Quick, Ultradent) applied for 30 min/week for 3 weeks. Levels of mercury were measured as weight percentages using an energy dispersive x-ray micro-analyzer detector connected to an electron microscope. Data was analyzed using one-way ANOVA and a post hoc Tukey tests (P<.05). Results: There were no significant differences between the surface mercury levels measured following treatment with the tested home-bleach and in-office bleach products (P=0.71). However, both materials yielded significantly more mercury levels than that of the control group (P<.001). Conclusions: The tested bleaching products significantly elevated the surface mercury levels of amalgam in vitro. PMID:20046476

  14. Making High-Tensile-Strength Amalgam Components

    NASA Technical Reports Server (NTRS)

    Grugel, Richard

    2008-01-01

    Structural components made of amalgams can be made to have tensile strengths much greater than previously known to be possible. Amalgams, perhaps best known for their use in dental fillings, have several useful attributes, including room-temperature fabrication, corrosion resistance, dimensional stability, and high compressive strength. However, the range of applications of amalgams has been limited by their very small tensile strengths. Now, it has been discovered that the tensile strength of an amalgam depends critically on the sizes and shapes of the particles from which it is made and, consequently, the tensile strength can be greatly increased through suitable choice of the particles. Heretofore, the powder particles used to make amalgams have been, variously, in the form of micron-sized spheroids or flakes. The tensile reinforcement contributed by the spheroids and flakes is minimal because fracture paths simply go around these particles. However, if spheroids or flakes are replaced by strands having greater lengths, then tensile reinforcement can be increased significantly. The feasibility of this concept was shown in an experiment in which electrical copper wires, serving as demonstration substitutes for copper powder particles, were triturated with gallium by use of a mortar and pestle and the resulting amalgam was compressed into a mold. The tensile strength of the amalgam specimen was then measured and found to be greater than 10(exp 4) psi (greater than about 69 MPa). Much remains to be done to optimize the properties of amalgams for various applications through suitable choice of starting constituents and modification of the trituration and molding processes. The choice of wire size and composition are expected to be especially important. Perusal of phase diagrams of metal mixtures could give insight that would enable choices of solid and liquid metal constituents. Finally, whereas heretofore, only binary alloys have been considered for amalgams

  15. Amalgam tattoo.

    PubMed

    Tran, Hien T; Anandasabapathy, Niroshana; Soldano, Anthony C

    2008-01-01

    A 53-year-old woman with a history of melanoma status-post excision two years prior presented with a 4-month history of 4, dark-brown macules on the inferior surface of her tongue. A biopsy specimen showed a squamous mucosa with chronic submucosal inflammation and brown pigment. The clinical and histopathologic findings were consistent with a diagnosis of amalgam tattoo. Amalgam tattoos are common, oral pigmented lesions that clinically present as isolated, blue, grey, or black macules on the gingivae, the buccal and alveolar mucosae, the palate, and/or the tongue. They are due to deposition of a mixture of silver, tin, mercury, copper, and zinc, which are components of an amalgam filling, into the oral soft tissues. Amalgam tattoos can either be treated surgically or with a Q-switched ruby laser. In the case of our patient with the history of melanoma, her oral lesions proved not to be the more dire diagnosis of malignant melanoma. PMID:18627755

  16. Lichenoid reaction associated to amalgam restoration.

    PubMed

    Segura-Egea, Juan José; Bullón-Fernández, Pedro

    2004-01-01

    Hypersensitivity to mercury associated with amalgam restorations may occur and present in one of two different ways. Most commonly it presents as an oral lichenoid reaction affecting oral mucosa in direct contact with an amalgam restoration and represents a delayed, type IV, cell mediated immune response to mercury or one of the other constituents of the dental amalgam. We report a case of oral lichenoid reaction associated to amalgam restoration. A 38 year-old woman presented a caries lesion of tooth #37. A Blacks class I preparation was performed and filled with amalgam. After 19 months, intra-oral examination revealed atrophic lesion, lightly erythematous, affecting the left buccal mucous. The lesion contacted directly with the amalgam restoration in the lower first molar. The right buccal mucosa was normal. His medical history was unremarkable, he was taking no medication and had no known allergies. However, the patient had felt certain rare sensation in that zone when eating sharp meals. Biopsy showed histological changes compatible with oral lichen planus. The patient decided not to change again the restoration, because she did not have important annoyances and she did not wish to be treated again. Other restorations were performed with composite resins, and no reaction was evidenced in the mucosa. PMID:15580119

  17. Use of Mercury in Dental Silver Amalgam: An Occupational and Environmental Assessment

    PubMed Central

    Jamil, Nadia; Ilyas, Samar; Qadir, Abdul; Arslan, Muhammad; Salman, Muhammad; Ahsan, Naveed; Zahid, Hina

    2016-01-01

    The objective of this study was to assess the occupational exposure to mercury in dentistry and associated environmental emission in wastewater of Lahore, Pakistan. A total of ninety-eight blood samples were collected comprising 37 dentists, 31 dental assistants, and 30 controls. Results demonstrate that the dentistry personnel contained significantly higher mean concentration of mercury in their blood samples (dentists: 29.835 µg/L and dental assistants: 22.798 µg/L) compared to that of the controls (3.2769 µg/L). The mean concentration of mercury was found maximum in the blood samples of older age group (62.8 µg/L) in dentists and (44.3 µg/L) in dental assistants. The comparison of mercury concentration among dentists, dental assistants, and controls (pairing based on their ages) revealed that the concentration increased with the age and experience among the dentists and dental assistants. Moreover, the mercury concentration in all the studied dental wastewater samples, collected from twenty-two dental clinics, was found to be exceeding the recommended discharge limit of 0.01 mg/L. Therefore, we recommend that immediate steps must be taken to ensure appropriate preventive measures to avoid mercury vapors in order to prevent potential health hazards to dentistry personnel. Strong regulatory and administrative measures are needed to deal with mercury pollution on emergency basis. PMID:27446955

  18. Use of Mercury in Dental Silver Amalgam: An Occupational and Environmental Assessment.

    PubMed

    Jamil, Nadia; Baqar, Mujtaba; Ilyas, Samar; Qadir, Abdul; Arslan, Muhammad; Salman, Muhammad; Ahsan, Naveed; Zahid, Hina

    2016-01-01

    The objective of this study was to assess the occupational exposure to mercury in dentistry and associated environmental emission in wastewater of Lahore, Pakistan. A total of ninety-eight blood samples were collected comprising 37 dentists, 31 dental assistants, and 30 controls. Results demonstrate that the dentistry personnel contained significantly higher mean concentration of mercury in their blood samples (dentists: 29.835 µg/L and dental assistants: 22.798 µg/L) compared to that of the controls (3.2769 µg/L). The mean concentration of mercury was found maximum in the blood samples of older age group (62.8 µg/L) in dentists and (44.3 µg/L) in dental assistants. The comparison of mercury concentration among dentists, dental assistants, and controls (pairing based on their ages) revealed that the concentration increased with the age and experience among the dentists and dental assistants. Moreover, the mercury concentration in all the studied dental wastewater samples, collected from twenty-two dental clinics, was found to be exceeding the recommended discharge limit of 0.01 mg/L. Therefore, we recommend that immediate steps must be taken to ensure appropriate preventive measures to avoid mercury vapors in order to prevent potential health hazards to dentistry personnel. Strong regulatory and administrative measures are needed to deal with mercury pollution on emergency basis. PMID:27446955

  19. An interview study of persons who attribute health problems to dental filling materials--part two in a triangulation study on 65 and 75 years old Swedes.

    PubMed

    Ståhlnacke, Katri; Söderfeldt, Björn

    2013-01-01

    Dental materials are perceived as a health problem by some people, although scientists do not agree about possible causes of such problems. The aim of this paper was to gain a deeper knowledge and understanding of experiences from living with health problems attributed to dental materials. Addressed topics were the type of problem, both as to general and oral health, perceived causes of the problems,their experienced effect on life, and reception by health professionals. Persons, who in a previous large questionnaire study had answered that they had experienced troubles from dental materials and also agreed to answer follow-up questions, were contacted with a request to take part in an interview study. Eleven individual interviews were held.The interviews were transcribed verbatim and the material was analysed according to the Qualitative Content Analysis method. Meaning units were extracted and condensed into a number of codes, which were combined into subcategories, categories, and themes. Four themes were identified: 1) Long-term oral, mental, and somatic difficulties of varying character, caused by dental amalgam. 2) Problems treated mainly by replacement of dental material in fillings. 3) Powerful effects on life, mostly negative. 4) The reception by health professionals was generally good, but with elements of encounters where they felt treated with nonchalance and lack of respect. In conclusion, people who attributed their health difficulties to dental materials had a complex range of problems and the perception was that amalgam/mercury was the cause of the troubles. The reception from health professionals was perceived as generally good, although with occasional negative experiences.

  20. Microstructural residual stress in particle-filled dental composite.

    PubMed

    Prejzek, Ondřej; Spaniel, Miroslav; Mareš, Tomáš

    2015-01-01

    The main goal of this study is to develop a micromechanical model of a particle-filled dental composite focused on the residual stress (RS) field developed during the curing process in its microstructure. A finite element model of a representative volume element of filler and resin was developed, and volumetric shrinkage was simulated during the curing process. Four material models (von Mises plasticity model, Drucker-Prager plasticity model, von Mises plasticity model with stress relaxation and Drucker-Prager plasticity with stress relaxation) of the polymer resin were built to assess the influence of the material model on the resulting internal stress. The relationship between the curing process and the magnitude of the stress components will be described, and an analysis of the post-curing state of the material in particular microstructure locations will be conducted in this study. Obtained RS is comparable to the stresses developed in the material under the external load. The substantial dependence on the choice of material model for resin is to be observed, and the suitability of particular models is discussed.

  1. High Tensile Strength Amalgams for In-Space Fabrication and Repair

    NASA Technical Reports Server (NTRS)

    Grugel, Richard N.

    2006-01-01

    Amalgams are well known for their use in dental practice as a tooth filling material. They have a number of useful attributes that include room temperature fabrication, corrosion resistance, dimensional stability, and very good compressive strength. These properties well serve dental needs but, unfortunately, amalgams have extremely poor tensile strength, a feature that severely limits other potential applications. Improved material properties (strength and temperature) of amalgams may have application to the freeform fabrication of repairs or parts that might be necessary during an extended space mission. Advantages would include, but are not limited to: the ability to produce complex parts, a minimum number of processing steps, minimum crew interaction, high yield - minimum wasted material, reduced gravity compatibility, minimum final finishing, safety, and minimum power consumption. The work presented here shows how the properties of amalgams can be improved by changing particle geometries in conjunction with novel engineering metals.

  2. High Tensile Strength Amalgams for In-Space Repair and Fabrication

    NASA Technical Reports Server (NTRS)

    Grugel, R. N.

    2005-01-01

    Amalgams are defined as an alloy of mercury with one or more other metals. These, along with those based on gallium (also liquid at near room temperature), are widely used in dental practice as a tooth filling material. Amalgams have a number of useful attributes that indude room temperature compounding. corrosion resistance, dimensional stability, and good compressive strength. These properties well serve dental needs but, unfortunately, amalgams have extremely poor tensile strength, a feature that severely limits their applications. The work presented here demonstrates how, by modifying particle geometry, the tensile strength of amalgams can be increased and thus extending the range of potential applications. This is relevant to, for example, the freeform fabrication of replacement parts that might be necessary during an extended space mission. Advantages, i.e. Figures-of-Merit. include the ability to produce complex parts, minimum crew interaction, high yield - minimum wasted material, reduced gravity compatibility, minimum final finishing, safety, and minimum power consumption.

  3. Performance of a gaseous detector based energy dispersive X-ray fluorescence imaging system: Analysis of human teeth treated with dental amalgam

    NASA Astrophysics Data System (ADS)

    Silva, A. L. M.; Figueroa, R.; Jaramillo, A.; Carvalho, M. L.; Veloso, J. F. C. A.

    2013-08-01

    Energy dispersive X-ray fluorescence (EDXRF) imaging systems are of great interest in many applications of different areas, once they allow us to get images of the spatial elemental distribution in the samples. The detector system used in this study is based on a micro patterned gas detector, named Micro-Hole and Strip Plate. The full field of view system, with an active area of 28 × 28 mm2 presents some important features for EDXRF imaging applications, such as a position resolution below 125 μm, an intrinsic energy resolution of about 14% full width at half maximum for 5.9 keV X-rays, and a counting rate capability of 0.5 MHz. In this work, analysis of human teeth treated by dental amalgam was performed by using the EDXRF imaging system mentioned above. The goal of the analysis is to evaluate the system capabilities in the biomedical field by measuring the drift of the major constituents of a dental amalgam, Zn and Hg, throughout the tooth structures. The elemental distribution pattern of these elements obtained during the analysis suggests diffusion of these elements from the amalgam to teeth tissues.

  4. Preparation of dental amalgam and spectral diagnosis of mercury in plasmas-laser in the region of 250 nm - 850 nm

    NASA Astrophysics Data System (ADS)

    De la Ossa, A.; Pacheco, P.; Sarmiento, R.

    2013-11-01

    In this paper we presents results of the spectral study of plasmas-laser of dental amalgam by technique Laser-induced Breakdown Spectroscopy (LIBS). Plasmas were generated focusing the beam of a Nd: YAG laser on the matrix of the mixture Ag-Sn-Cu and on amalgams with different proportions of mercury (3:2, 5:2, 6:2). Based on the spectral results and reported atomic parameters, became estimation of electron temperature plasmas- laser and their behavior with the concentration of Hg. The estimated values of the electron temperature for the respective proportions were 20 846 K, 19 139 K and 16 872 K, using the distribution of population of Boltzmann energy levels associated with spectral lines, considering conditions Local Thermodinamic Equilibrium (LTE) of plasmas.

  5. DEVELOPMENT AND VERIFICATION OF NEW SOLID DENTAL FILLING TEMPORARY MATERIALS CONTAINING ZINC. FORMULA DEVELOPMENT STAGE.

    PubMed

    Pytko-Polończyk, Jolanta; Antosik, Agata; Zajac, Magdalena; Szlósarczyk, Marek; Krywult, Agnieszka; Jachowicz, Renata; Opoka, Włodzimierz

    2016-01-01

    Caries is the most popular problem affecting teeth and this is the reason why so many temporary dental filling materials are being developed. An example of such filling is zinc oxide paste mixed with eugenol, Thymodentin and Coltosol F®. Zinc-oxide eugenol is used in dentistry because of its multiplied values: it improves heeling of the pulp by dentine bridge formation; has antiseptic properties; is hygroscopic. Because of these advantages compouds of zinc oxide are used as temporary fillings, especially in deep caries lesions when treatment is oriented on support of vital pulp. Temporary dental fillings based on zinc oxide are prepared ex tempone by simple mixing powder (Thymodentin) and eugenol liqiud together or a ready to use paste Coltosol F®. Quantitative composition depends mainly on experience of person who is preparing it, therefore, exact qualitative composition of dental fillings is not replicable. The main goal of the study was to develop appropriate dental fillings in solid form containing set amount of zinc oxide. Within the study, the influence of preparation method on solid dental fillings properties like mechanical properties and zinc ions release were examined.

  6. Dosimetric consideration for patients with dental filling materials undergoing irradiation of oral cavity using RapidArc: challenges and solution

    NASA Astrophysics Data System (ADS)

    Mail, Noor; Albarakati, Y.; Khan, M. Ahmad; Saeedi, F.; Safadi, N.; Al-Ghamdi, S.; Saoudi, A.

    2012-03-01

    In this study, we investigate the effect of dental filling materials (DFM) on RapidArcTM treatment plans and delivery in a patient undergoing radiotherapy treatment. The presence of DFM creates uncertainties in CT number and causes long streaking artifacts in the reconstructed images which greatly affect the dose distribution inside the oral cavity. The influence of extensive dental filling artifacts on dose distribution was performed using a geometrically well defined head and neck IMRT verification phantom (PTW, Freiburg, Germany) together with inserts from DFM (Amalgam, 11.3 g/cm3). The phantom was scanned using Siemens SOMATOM Sensation CT simulator (Siemens AG, Germany) under standard head and neck imaging protocol (120 kV, 120 mAs, voxel size 1×1×2 mm3). Three RapidArcTM plans were created in the Varian Eclipse treatment planning System (TPS) to treat oral cavity using the same CT dataset including; 1) raw CT image, 2) streaking artifacts replaced with a mask of 10 HU and 3) 2 cm thick 6000 HU virtual filter (a volume around the teeth in TPS to mimic extra attenuation). The virtual filter thickness optimization was purely based on measured PDD data acquired with DFM and the calculation in Eclipse Planning System using direct beam. The dose delivery and distribution for the three plans was verified using Gafchromic EBT2 (International Specialty Product, Wayne, NJ, USA) film measurements. The artifact mask and virtual filter around the teeth in the planning was found very useful to reduce the discrepancies between the dose plan and delivery. From clinical point of view, these results can be helpful to understand the increase of mucositis in patient having DFM, and further investigation is underway for clinical solution.

  7. Radiopacities in dentine under amalgam restorations.

    PubMed

    Rudolphy, M P; van Amerongen, J P; ten Cate, J M

    1994-01-01

    Radiopacities, caused by tin or zinc deposits in partly demineralized dental tissue, are frequently seen under amalgam restorations. The aim of this study was to determine to what extent these radiopaque areas could be identified by Caries Detector (1% acid red in propylene glycol) which is claimed to stain the irreversibly demineralized dentine. Twenty-eight extracted teeth showing radiopacities under amalgam fillings were selected. The restorations were removed, and Caries Detector was applied. Caries was excavated until the dentine did no longer stain with the Caries Detector. Standardized radiographs were taken at different stages. In all teeth the radiopaque areas stained with the Caries Detector. Visual inspection of the radiographs, taken after excavation, revealed that the radiopacities had disappeared completely in 6 teeth; in 5 teeth a very small part of the radiopaque area remained; in 17 teeth the cavity floor appeared as a thin white line on X-ray. Overall, line scan analysis confirmed the data obtained by visual observation. The residual radiopacities and radiopaque lines were a very small fraction of the initial radiopacities. Therefore, it is concluded that the radiopaque zone under amalgam fillings represents almost entirely an area of irreversibly demineralized dentine as indicated by the Caries Detector.

  8. Cytotoxic effects of bulk fill composite resins on human dental pulp stem cells.

    PubMed

    Şişman, Reyhan; Aksoy, Ayça; Yalçın, Muhammet; Karaöz, Erdal

    2016-01-01

    Five bulk fill composite resins, including SDR, Tetric EvoCeram Bulk Fill (TEC), X-trafil (XTF), Sonic Fill (SF), Filtek Bulk Fill (FBF), were used in this study. Human dental pulp stem cells were cultured in 12-well culture dishes (3 × 104 cells per cm(2)) and stored in an incubator at 37°C and 5% CO2 for 1 day. On days 1, 7, 14, and 21 of co-culture, viable cells were measured using a WST-1 assay. Lower cell viability was observed with XTF and SDR bulk fill composite resins compared to the control group during the WST-1 assay. Although bulk fill composite resins provide advantages in practical applications, they are limited by their cytotoxic properties. (J Oral Sci 58, 299-305, 2016).

  9. Cytotoxic effects of bulk fill composite resins on human dental pulp stem cells.

    PubMed

    Şişman, Reyhan; Aksoy, Ayça; Yalçın, Muhammet; Karaöz, Erdal

    2016-01-01

    Five bulk fill composite resins, including SDR, Tetric EvoCeram Bulk Fill (TEC), X-trafil (XTF), Sonic Fill (SF), Filtek Bulk Fill (FBF), were used in this study. Human dental pulp stem cells were cultured in 12-well culture dishes (3 × 104 cells per cm(2)) and stored in an incubator at 37°C and 5% CO2 for 1 day. On days 1, 7, 14, and 21 of co-culture, viable cells were measured using a WST-1 assay. Lower cell viability was observed with XTF and SDR bulk fill composite resins compared to the control group during the WST-1 assay. Although bulk fill composite resins provide advantages in practical applications, they are limited by their cytotoxic properties. (J Oral Sci 58, 299-305, 2016). PMID:27665967

  10. Are there acceptable alternatives to amalgam?

    PubMed

    Mackert, J Rodway; Wahl, Michael J

    2004-07-01

    Amalgam has been the material of choice for restoring posterior teeth for more than 100 years. The past 25 years have witnessed significant advances in restorative materials themselves and in the bonding systems for retaining a restoration in the prepared tooth. As a result, there has been a shift toward resin composite materials during this same period because of concerns about the esthetics and biocompatibility of dental amalgam. In addition, other materials such as glass ionomer cements, ceramic inlays and onlays, and gold alloys have been used as alternatives to amalgam. This article will review recent studies on the longevity and biocompatibility of these alternatives to dental amalgam.

  11. Mechanical Properties Comparing Composite Fiber Length to Amalgam

    PubMed Central

    Petersen, Richard C.; Liu, Perng-Ru

    2016-01-01

    Photocure fiber-reinforced composites (FRCs) with varying chopped quartz-fiber lengths were incorporated into a dental photocure zirconia-silicate particulate-filled composite (PFC) for mechanical test comparisons with a popular commercial spherical-particle amalgam. FRC lengths included 0.5-mm, 1.0 mm, 2.0 mm, and 3.0 mm all at a constant 28.2 volume percent. Four-point fully articulated fixtures were used according to American Standards Test Methods with sample dimensions of 2×2×50 mm3 across a 40 mm span to provide sufficient Euler flexural bending and prevent top-load compressive shear error. Mechanical properties for flexural strength, modulus, yield strength, resilience, work of fracture, critical strain energy release, critical stress intensity factor, and strain were obtained for comparison. Fiber length subsequently correlated with increasing all mechanical properties, p < 1.1×10−5. Although the modulus was significantly statistically higher for amalgam than all composites, all FRCs and even the PFC had higher values than amalgam for all other mechanical properties. Because amalgams provide increased longevity during clinical use compared to the standard PFCs, modulus would appear to be a mechanical property that might sufficiently reduce margin interlaminar shear stress and strain-related microcracking that could reduce failure rates. Also, since FRCs were tested with all mechanical properties that statistically significantly increased over the PFC, new avenues for future development could be provided toward surpassing amalgam in clinical longevity. PMID:27642629

  12. Mechanical Properties Comparing Composite Fiber Length to Amalgam

    PubMed Central

    Petersen, Richard C.; Liu, Perng-Ru

    2016-01-01

    Photocure fiber-reinforced composites (FRCs) with varying chopped quartz-fiber lengths were incorporated into a dental photocure zirconia-silicate particulate-filled composite (PFC) for mechanical test comparisons with a popular commercial spherical-particle amalgam. FRC lengths included 0.5-mm, 1.0 mm, 2.0 mm, and 3.0 mm all at a constant 28.2 volume percent. Four-point fully articulated fixtures were used according to American Standards Test Methods with sample dimensions of 2×2×50 mm3 across a 40 mm span to provide sufficient Euler flexural bending and prevent top-load compressive shear error. Mechanical properties for flexural strength, modulus, yield strength, resilience, work of fracture, critical strain energy release, critical stress intensity factor, and strain were obtained for comparison. Fiber length subsequently correlated with increasing all mechanical properties, p < 1.1×10−5. Although the modulus was significantly statistically higher for amalgam than all composites, all FRCs and even the PFC had higher values than amalgam for all other mechanical properties. Because amalgams provide increased longevity during clinical use compared to the standard PFCs, modulus would appear to be a mechanical property that might sufficiently reduce margin interlaminar shear stress and strain-related microcracking that could reduce failure rates. Also, since FRCs were tested with all mechanical properties that statistically significantly increased over the PFC, new avenues for future development could be provided toward surpassing amalgam in clinical longevity.

  13. Amalgam at the new millennium.

    PubMed

    Berry, T G; Summitt, J B; Chung, A K; Osborne, J W

    1998-11-01

    Dental amalgam has served as an excellent and versatile restorative material for many years, despite periods of controversy. The authors review its history, summarize the evidence in regard to its performance and offer predictions for the future of this material. For the present, amalgam should remain the material of choice for economical direct restoration of posterior teeth. When esthetic concerns are paramount, tooth-colored materials, placed meticulously, can provide an acceptable alternative.

  14. SU-E-T-365: Dosimetric Impact of Dental Amalgam CT Image Artifacts On IMRT and VMAT Head and Neck Plans

    SciTech Connect

    Cao, N; Young, L; Parvathaneni, U; Liao, J; Richard, P; Ford, E; Sandison, G

    2014-06-01

    Purpose: The presence of high density dental amalgam in patient CT image data sets causes dose calculation errors for head and neck (HN) treatment planning. This study assesses and compares dosimetric variations in IMRT and VMAT treatment plans due to dental artifacts. Methods: Sixteen HN patients with similar treatment sites (oropharynx), tumor volume and extensive dental artifacts were divided into two groups: IMRT (n=8, 6 to 9 beams) and VMAT (n=8, 2 arcs with 352° rotation). All cases were planned with the Pinnacle 9.2 treatment planning software using the collapsed cone convolution superposition algorithm and a range of prescription dose from 60 to 72Gy. Two different treatment plans were produced, each based on one of two image sets: (a)uncorrected; (b)dental artifacts density overridden (set to 1.0g/cm{sup 3}). Differences between the two treatment plans for each of the IMRT and VMAT techniques were quantified by the following dosimetric parameters: maximum point dose, maximum spinal cord and brainstem dose, mean left and right parotid dose, and PTV coverage (V95%Rx). Average differences generated for these dosimetric parameters were compared between IMRT and VMAT plans. Results: The average absolute dose differences (plan a minus plan b) for the VMAT and IMRT techniques, respectively, caused by dental artifacts were: 2.2±3.3cGy vs. 37.6±57.5cGy (maximum point dose, P=0.15); 1.2±0.9cGy vs. 7.9±6.7cGy (maximum spinal cord dose, P=0.026); 2.2±2.4cGy vs. 12.1±13.0cGy (maximum brainstem dose, P=0.077); 0.9±1.1cGy vs. 4.1±3.5cGy (mean left parotid dose, P=0.038); 0.9±0.8cGy vs. 7.8±11.9cGy (mean right parotid dose, P=0.136); 0.021%±0.014% vs. 0.803%±1.44% (PTV coverage, P=0.17). Conclusion: For the HN plans studied, dental artifacts demonstrated a greater dose calculation error for IMRT plans compared to VMAT plans. Rotational arcs appear on the average to compensate dose calculation errors induced by dental artifacts. Thus, compared to VMAT, density

  15. A galvanic study of different amalgams.

    PubMed

    Wang Chen, C P; Greener, E H

    1977-01-01

    Due to the difference in open circuit potential (OCP) versus SCE for Aristaloy amalgam (-969 mV) and Dispersalloy amalgam (-549 mV) in Ringer's solution at 25 degrees C, a galvanic cell was created with Dispersalloy amalgam as cathode and Aristaloy amalgam as anode. The galvanic corrosion current was studied as a function of time for the above cell as well as for a cell of type III dental gold (OCP is +0-5 mV) versus Aristaloy amalgam. The initial corrosion current of the latter cell (105 micronA) is about twice that for the cell of Aristaloy amalgam versus Dispersalloy amalgam (54 micronA), however, their passivating behaviour is quite similar. Also, an interrupted galvanic corrosion test simulating the oral 'make and break' situation was performed. A much higher corrosion current than the steady state was found when the two electrodes resumed contact.

  16. [Black or white--Which choice for the molars? Part 2. Which does one choose for the restoration of posterior teeth: amalgam or composite?].

    PubMed

    De Moor, Roeland; Delmé, Katleen

    2008-01-01

    The two direct dental restorative materials most commonly used today are silver-mercury amalgam and resin-based composite. The survival of dental amalgam restorations is twice as high than for composite fillings: polymerisation shrinkage, deficient marginal adaptation, higher wear rates, defective contact points leading to food impaction, insufficiently converted composite at the bottom of the cavity are problems that cannot be underestimated when using resin-composite. This does not imply that there is no weakness for amalgam: the need for retentive cavities at the cost of healthy tooth substance, weakening of the tooth's strength by cutting through the tooth crown's ridges, the risk of fracture of remaining tooth substance (mostly buccal and lingual surfaces) as the result of the cavity design, and the lack of adhesion between amalgam and tooth substance. Retaining a tooth's strength by the replacement of amalgam by resin-composites is not always the correct solution. In this respect, it can be questioned whether it is not appropriate to repair failing (extensive) amalgam restorations as to replace them with resin-composites. Research in this respect has demonstrated that dentists still are not convinced of this treatment option. Restoring a tooth in its original build-up or structure and function within the oral cavity is the basis of the biomimetic principle: the use of composite appears to be more obvious than restoring with amalgam. In the present survey pro's and con's of amalgams and resin-composites for the restoration of posterior teeth are weighted. The conclusion demonstrates that there is still a place for dental amalgam in modern restorative dentistry when plastic filling materials are used for the direct tooth repair or restoration.

  17. Extensive amalgam tattoo on the alveolar-gingival mucosa.

    PubMed

    Galletta, Vivian C; Artico, Gabriela; Dal Vechio, Aluana M C; Lemos Jr, Celso A; Migliari, Dante A

    2011-01-01

    Amalgam tattoos are common exogenous pigmented lesions of the oral mucosa occurring mainly by inadvertent placement of amalgam particles into soft tissues. The diagnosis of amalgam tattoo is simple, usually based on clinical findings associated with presence or history of amalgam fillings removal. Intraoral X-rays may be helpful in detecting amalgam-related radiopacity. In cases where amalgam tattoo cannot be differentiated from other causes of oral pigmentation, a biopsy should be performed. This article deals with an extensive amalgam tattoo lesion which required a biopsy for a definitive diagnosis. PMID:22147048

  18. A 24-month Evaluation of Amalgam and Resin-Based Composite Restorations: Findings from The National Dental Practice-Based Research Network

    PubMed Central

    McCracken, Michael S.; Gordan, Valeria V.; Litaker, Mark S.; Funkhouser, Ellen; Fellows, Jeffrey L.; Shamp, Douglass G.; Qvist, Vibeke; Meral, Jeffrey S.; Gilbert, Gregg H.

    2013-01-01

    Background Knowing which factors influence restoration longevity can help clinicians make sound treatment decisions. The authors analyzed data from the National Dental Practice-Based Research Network to identify predictors of early failures of amalgam and resin-based composite (RBC) restorations. Methods This prospective cohort study gathered information from clinicians and offices participating in the network. Clinicians completed a baseline data collection form at the time of restoration placement, and annually thereafter. Data collected included patient factors, practice factors, and dentist factors, and were analyzed using mixed-model logistic regression. Results A total of 226 practitioners followed 6,218 direct restorations in 3,855 patients; 386 restorations failed (6.6 percent) during the mean follow-up period of 23.7 (SD 8.8) months. The number of tooth surfaces restored at baseline predicted subsequent restoration failure; large restorations were over 4 times more likely to fail. Material was not significantly associated with longevity; neither was tooth type. Patient age was highly associated with failure (p<0.0001). The failure rate for children was 5 percent, compared to 12 percent in persons 65 years old or older. Dentist gender and practice workload were significantly associated with restoration longevity. Conclusions In this prospective cohort study, these factors significantly predicted an increased failure rate for amalgam and RBC restorations: older patient age and a higher number of surfaces restored at baseline, with other key baseline variables taken into account. Material choice was not significantly predictive in these early results. Clinical Implications Understanding risk factors for early restoration failure may lead to more-effective patient care. PMID:23729455

  19. The impacts of dental filling materials on RapidArc treatment planning and dose delivery: Challenges and solution

    SciTech Connect

    Mail, Noor; Al-Ghamdi, S.; Saoudi, A.; Albarakati, Y.; Ahmad Khan, M.; Saeedi, F.; Safadi, N.

    2013-08-15

    Purpose: The presence of high-density material in the oral cavity creates dose perturbation in both downstream and upstream directions at the surfaces of dental filling materials (DFM). In this study, the authors have investigated the effect of DFM on head and neck RapidArc treatment plans and delivery. Solutions are proposed to address (1) the issue of downstream dose perturbation, which might cause target under dosage, and (2) to reduce the upstream dose from DFM which may be the primary source of mucositis. In addition, an investigation of the clinical role of a custom-made plastic dental mold/gutter (PDM) in sparing the oral mucosa and tongue reaction is outlined.Methods: The influence of the dental filling artifacts on dose distribution was investigated using a geometrically well-defined head and neck intensity modulated radiation therapy (IMRT) verification phantom (PTW, Freiberg, Germany) with DFM inserts called amalgam, which contained 50% mercury, 25% silver, 14% tin, 8% copper, and 3% other trace metals. Three RapidArc plans were generated in the Varian Eclipse System to treat the oral cavity using the same computer tomography (CT) dataset, including (1) a raw CT image, (2) a streaking artifacts region, which was replaced with a mask of 10 HU, and (3) a 2 cm-thick 6000 HU virtual filter [a volume created in treatment planning system to compensate for beam attenuation, where the thickness of this virtual filter is based on the measured percent depth dose (PDD) data and Eclipse calculation]. The dose delivery for the three plans was verified using Gafchromic-EBT2 film measurements. The custom-made PDM technique to reduce backscatter dose was clinically tested on four head and neck cancer patients (T3, N1, M0) with DFM, two patients with PDM and the other two patients without PDM. The thickness calculation of the PDM toward the mucosa and tongue was purely based on the measured upstream dose. Patients’ with oral mucosal reaction was clinically examined

  20. Combined amalgam and composite restorations.

    PubMed

    Abu-Hanna, Amer A; Mjör, Ivar A

    2004-01-01

    All indirect restorative techniques involving cast metals, ceramics or resin-based materials are expensive compared to directly placed restorations. A restorative technique is presented that combines the esthetic properties of directly bonded resin-based composite material and the wide range of indications for dental amalgam in stress-bearing areas.

  1. Corrosion behavior and microhardness of three amalgams.

    PubMed

    Patsurakos, A; Moberg, L E

    1988-08-01

    The marginal microhardness of three different types of amalgam was tested after 2 months' immersion in an aqueous solution of NaCl (85 mM) and phosphates (Na2HPO4 100 mM and NaH2PO4 100 mM). Amalgams immersed in distilled water were used as controls. The microhardness tests were conducted at a distance of 50 micron from the margins and at the bulk of each specimen. The solutions were analyzed for Sn, Cu, Zn, Ag, and Hg by means of atomic absorption spectrophotometry (AAS). A statistically significant reduction in the marginal microhardness after immersion in the test solution was found for the conventional and the high-Cu single composition amalgam but not for the high-Cu blended amalgam. SEM-examination of cross-sections of the amalgams revealed small areas of subsurface grain boundary corrosion, no deeper than 10 micron for all the amalgams. The SEM-examination of the specimens and AAS analysis of the solutions indicated that the reduction in marginal microhardness was attributed mainly to corrosion of the Cu-rich phases for the high-Cu single composition amalgam and to corrosion of the gamma 2 phase for the conventional amalgam. The phosphates reduced the corrosion of the amalgams in the presence of NaCl. It is concluded that the marginal strength of dental amalgams in a corrosive environment is largely dependent upon their corrosion resistance.

  2. Low-intensity lasers, modern filling materials, and bonding systems influence on mineral metabolism of hard dental tissues

    NASA Astrophysics Data System (ADS)

    Kunin, Anatoly A.; Yesaulenko, I. E.; Zoibelmann, M.; Pankova, Svetlana N.; Ippolitov, Yu. A.; Oleinik, Olga I.; Popova, T. A.; Koretskaya, I. V.; Shumilovitch, Bogdan R.; Podolskaya, Elana E.

    2001-10-01

    One of the main reasons of low quality filling is breaking Ca-P balance in hard tissues. Our research was done with the purpose of studying the influence of low intensity lasers, diodic radiation, the newest filling and bonding systems on the processes of mineral metabolism in hard dental tissues while filling a tooth. 250 patients having caries and its compli-cations were examined and treated. Our complex research included: visual and instrumental examination, finding out the level of oral cavity hygiene, acid enamel biopsy, scanning electronic microscopy and X-ray spectrum microanalysis. Filling processes may produce a negative effect on mineral metabolism of hard dental tissues the latter is less pronounced when applying fluoride-containing filling materials with bonding systems. It has also been found that bonding dentin and enamel systems are designed for both a better filling adhesion (i.e. mechanical adhesion) and migration of useful microelements present in them by their sinking into hard dental tissues (i.e. chemical adhesion). Our research showed a positive influence of low intensity laser and diodic beams accompanying the use of modern filling and bonding systems on mineral metabolism of hard dental tissues.

  3. Neurological symptoms among dental assistants: a cross-sectional study

    PubMed Central

    Moen, BE; Hollund, BE; Riise, T

    2008-01-01

    Background Dental assistants help the dentist in preparing material for filling teeth. Amalgam was the filling material mostly commonly used in Norway before 1980, and declined to about 5% of all fillings in 2005. Amalgam is usually an alloy of silver, copper, tin and mercury. Copper amalgam, giving particularly high exposure to mercury was used in Norway until 1994. Metallic mercury is neurotoxic. Few studies of the health of dental assistants exist, despite their exposure to mercury. There are questions about the existence of possible chronic neurological symptoms today within this working group, due to this exposure. The aim of this study was to compare the occurrence of neurological symptoms among dental assistants likely to be exposed to mercury from work with dental filling material, compared to similar health personnel with no such exposure. Methods All dental assistants still at work and born before 1970 registered in the archives of a trade union in Hordaland county of Norway were invited to participate (response rate 68%, n = 41), as well as a similar number of randomly selected assistant nurses (response rate 87%, n = 64) in the same age group. The participants completed a self-administered, mailed questionnaire, with questions about demographic variables, life-style factors, musculoskeletal, neurological and psychosomatic symptoms (Euroquest). Results The dental assistants reported significant higher occurrence of neurological symptoms; psychosomatic symptoms, problems with memory, concentration, fatigue and sleep disturbance, but not for mood. This was found by analyses of variance, adjusting for age, education, alcohol consumption, smoking and personality traits. For each specific neurological symptom, adjusted logistic regression analyses were performed, showing that these symptoms were mainly from arms, hands, legs and balance organs. Conclusion There is a possibility that the higher occurrence of neurological symptoms among the dental assistants

  4. [Amalgam risk assessment with coverage of references up to 2005].

    PubMed

    Mutter, J; Naumann, J; Walach, H; Daschner, F

    2005-03-01

    Amalgam, which has been in use in dentistry for 150 years, consists of 50 % elemental mercury and a mixture of silver, tin, copper and zinc. Minute amounts of mercury vapour are released continuously from amalgam. Amalgam contributes substantially to human mercury load. Mercury accumulates in some organs, particularly in the brain, where it can bind to protein more tightly than other heavy metals (e. g. lead, cadmium). Therefore, the elimination half time is assumed to be up to 1 - 18 years in the brain and bones. Mercury is assumed to be one of the most toxic non-radioactive elements. There are pointers to show that mercury vapour is more neurotoxic than methyl-mercury in fish. Review of recent literature suggests that mercury from dental amalgam may lead to nephrotoxicity, neurobehavioural changes, autoimmunity, oxidative stress, autism, skin and mucosa alterations or non-specific symptoms and complaints. The development of Alzheimer's disease or multiple sclerosis has also been linked to low-dose mercury exposure. There may be individual genetical or acquired susceptibilities for negative effects from dental amalgam. Mercury levels in the blood, urine or other biomarkers do not reflect the mercury load in critical organs. Some studies regarding dental amalgam reveal substantial methodical flaws. Removal of dental amalgam leads to permanent improvement of various chronic complaints in a relevant number of patients in various trials. Summing up, available data suggests that dental amalgam is an unsuitable material for medical, occupational and ecological reasons.

  5. [Amalgam risk assessment with coverage of references up to 2005].

    PubMed

    Mutter, J; Naumann, J; Walach, H; Daschner, F

    2005-03-01

    Amalgam, which has been in use in dentistry for 150 years, consists of 50 % elemental mercury and a mixture of silver, tin, copper and zinc. Minute amounts of mercury vapour are released continuously from amalgam. Amalgam contributes substantially to human mercury load. Mercury accumulates in some organs, particularly in the brain, where it can bind to protein more tightly than other heavy metals (e. g. lead, cadmium). Therefore, the elimination half time is assumed to be up to 1 - 18 years in the brain and bones. Mercury is assumed to be one of the most toxic non-radioactive elements. There are pointers to show that mercury vapour is more neurotoxic than methyl-mercury in fish. Review of recent literature suggests that mercury from dental amalgam may lead to nephrotoxicity, neurobehavioural changes, autoimmunity, oxidative stress, autism, skin and mucosa alterations or non-specific symptoms and complaints. The development of Alzheimer's disease or multiple sclerosis has also been linked to low-dose mercury exposure. There may be individual genetical or acquired susceptibilities for negative effects from dental amalgam. Mercury levels in the blood, urine or other biomarkers do not reflect the mercury load in critical organs. Some studies regarding dental amalgam reveal substantial methodical flaws. Removal of dental amalgam leads to permanent improvement of various chronic complaints in a relevant number of patients in various trials. Summing up, available data suggests that dental amalgam is an unsuitable material for medical, occupational and ecological reasons. PMID:15789284

  6. Distribution of toxic elements in teeth treated with amalgam using μ-energy dispersive X-ray fluorescence

    NASA Astrophysics Data System (ADS)

    Guerra, M.; Ferreira, C.; Carvalho, M. L.; Santos, J. P.; Pessanha, S.

    2016-08-01

    Over the years, the presence of mercury in amalgam fillings has raised some safety concerns. Amalgam is one of the most commonly used tooth fillings and contains approximately 50% of elemental mercury and 50% of other metals, mostly silver, tin and copper. Amalgam can release small amounts of mercury vapor over time, and patients can absorb these vapors by inhaling or ingesting them. In this study, 10 human teeth treated with dental amalgam were analyzed using energy dispersive X-ray fluorescence (EDXRF) to study the diffusion of its constituents, Ag, Cu, Sn and Hg. The used EDXRF setup, makes use of a polycapillary lens to focus radiation up to 25 μm allowing the mapping of the elemental distribution in the samples. Quantification was performed using the inbuilt software based on the Fundamental Parameters method for bulk samples, considering a hydroxyapatite matrix. The teeth were longitudinally cut and each slice was scanned from the surface enamel to the inner region (dentin and pulp cavity). Mercury concentration profiles show strong levels of this element close to the amalgam region, decreasing significantly in the dentin, and increasing again up to 40,000 μg·g- 1 in the cavity were the pulp used to exist when the tooth was vital.

  7. Mercury release during autoclave sterilization of amalgam.

    PubMed

    Parsell, D E; Karns, L; Buchanan, W T; Johnson, R B

    1996-05-01

    Natural teeth are an invaluable teaching tool for preclinical instruction in operative dentistry and endodontic techniques. Cavity preparation in teeth containing amalgam restorations is a realistic simulation of an often experienced clinical situation. As various pathogens are contained in saliva, teeth must be disinfected before use by students. The purpose of this study is to indirectly evaluate whether mercury vapor is released from amalgam restorations in such teeth during steam autoclave sterilization. Mercury vapor detection, sample mass changes and x-ray fluorescence data were collected from experimental steam autoclave sterilization of amalgam samples sealed in autoclave bags. All of the data showed evidence of mercury vapor generation coincident to steam autoclave sterilization. Mercury vapor levels within the room where amalgam was exposed to steam autoclave sterilization reached levels that constitute an unnecessary health risk to dental personnel. The volume of amalgam tested simulated that contained in 175 amalgam restored teeth. Initial venting of the autoclave chamber produced mercury vapor concentrations significantly in excess of OSHA vapor concentration ceiling levels. Thus, the use of a steam autoclave for sterilization of amalgam containing teeth for use in preclinical laboratory exercises may be harmful to personnel involved.

  8. Effect of pellicle on galvanic corrosion of amalgam.

    PubMed

    Holland, R I

    1984-02-01

    Galvanic corrosion of amalgam, induced by contact with a type IV dental casting gold alloy, was determined under simulated oral conditions in an electrochemical cell. The effect of a pellicle layer formed by 1 h exposure to saliva in the oral cavity was determined. Pellicle on the amalgam had no effect on the maximum corrosion rate or the 2 h corrosion charge, whereas pellicle on the gold alloy substantially reduced both these parameters of the conventional low-copper amalgam; the corrosion of the high-copper amalgam was less and was not influenced by pellicle formation.

  9. Dental Stem Cell Migration on Pulp Ceiling Cavities Filled with MTA, Dentin Chips, or Bio-Oss

    PubMed Central

    Lymperi, Stefania; Taraslia, Vasiliki; Tsatsoulis, Ioannis N.; Samara, Athina; Velentzas, Athanasios D.; Agrafioti, Anastasia; Anastasiadou, Ema; Kontakiotis, Evangelos

    2015-01-01

    MTA, Bio-Oss, and dentin chips have been successfully used in endodontics. The aim of this study was to assess the adhesion and migration of dental stem cells on human pulp ceiling cavities filled with these endodontic materials in an experimental model, which mimics the clinical conditions of regenerative endodontics. Cavities were formed, by a homemade mold, on untouched third molars, filled with endodontic materials, and observed with electron microscopy. Cells were seeded on cavities' surface and their morphology and number were analysed. The phenomenon of tropism was assessed in a migration assay. All three materials demonstrated appropriate microstructures for cell attachment. Cells grew on all reagents, but they showed a differential morphology. Moreover, variations were observed when comparing cells numbers on cavity's filling versus the surrounding dentine disc. The highest number of cells was recorded on dentin chips whereas the opposite was true for Bio-Oss. This was confirmed in the migration assay where a statistically significant lower number of cells migrated towards Bio-Oss as compared to MTA and dentin chips. This study highlights that MTA and dentin chips have a greater potential compared to Bio-Oss regarding the attraction of dental stem cells and are good candidates for bioengineered pulp regeneration. PMID:26146613

  10. Characterization of dental fillings found in skulls from individuals buried in San Jeronimos Church, New Spain: historical and archaeological evidences.

    PubMed

    Mansilla, J; Romero, C; Bosch, P; Leboreiro, I; Pijoan, C

    2006-01-01

    Repair of teeth during the XIX century was often a very costly and painful procedure. During this period, restoration of teeth was a procedure limited only to those who could afford such care. In this study we analyzed teeth from a skull sample found in San Jeronimo's Church. The characterization of molar fillings was made with techniques such as X-ray fluorescence, X-ray diffraction and electron microscopy. The purpose of this investigation was to establish technical procedures for analysis, and to discuss the results within the context of the socioeconomic status of these individuals and the written descriptions of the dental practice during the XIX century.

  11. Evaluation of Marginal Integrity of Four Bulk-Fill Dental Composite Materials: In Vitro Study

    PubMed Central

    Orłowski, Mirosław; Tarczydło, Bożena; Chałas, Renata

    2015-01-01

    Objective. The aim of the study was to compare under in vitro conditions marginal sealing of 4 different bulk-fill materials composite restorations of class II. Methods. Comparative evaluation concerned 4 composites of a bulk-fill type: SonicFill, Tetric EvoCeram Bulk Fill, Filtek Bulk Fill, and SDR. The study used 30 third molars without caries. In each tooth 4 cavities of class II were prepared. The prepared tooth samples were placed in a 1% methylene blue solution for 24 h, and after that in each restoration the depth of dye penetration along the side walls was evaluated. Results. The highest rating (score 0, no dye penetration) was achieved by 93.33% of the restorations made of the SDR material, 90% of restorations of SonicFill system, 86.66% of restorations of the composite Filtek Bulk Fill, and 73.33% of restorations of the Tetric EvoCeram Bulk Fill. Conclusion. The performed study showed that bulk-fill flowable or sonic-activated flowable composite restorations have better marginal sealing (lack of discoloration) in comparison with bulk-fill paste-like composite. PMID:25874254

  12. Evaluation of simulation learning materials use to fill the gap in Japanese dental English education.

    PubMed

    Seki, Naoko; Moross, Janelle; Sunaga, Masayo; Hobo, Koki; Miyoshi, Tomoe; Nitta, Hiroshi; Kinoshita, Atsuhiro; Morio, Ikuko

    2016-01-01

    Even though English is most frequently the common language when the patient's native language differs from that of a dentist, the opportunities for Japanese undergraduate dental students to learn dental English are now quite limited. The purposes of our study were to investigate: the effectiveness and feasibility of the computer-assisted simulation materials as one solution strategy for dental English education in Japan, and the needs and demands for dental English from the learners' side. Interactive simulation materials for medical interviews in English and clinical cases which were translated to English, were delivered via Learning Management System (LMS) to nineteen trainee residents of dentistry (residents). Evaluation for the materials, learners' knowledge and interests in the contents, and ease of operation were obtained by post-questionnaire (response rates were 100% and 95%, respectively). Both questionnaire-surveys received positive feedback toward the materials, yet 47% answered that they lacked the level of knowledge about contents of the medical interview in English. Results were sufficient to suggest that the residents would like to have the opportunity to study or practice medical interview in English, or English related to dentistry, and that the simulation materials could be one of the solution strategies for opportunity provision. PMID:27181485

  13. Evaluation of simulation learning materials use to fill the gap in Japanese dental English education.

    PubMed

    Seki, Naoko; Moross, Janelle; Sunaga, Masayo; Hobo, Koki; Miyoshi, Tomoe; Nitta, Hiroshi; Kinoshita, Atsuhiro; Morio, Ikuko

    2016-01-01

    Even though English is most frequently the common language when the patient's native language differs from that of a dentist, the opportunities for Japanese undergraduate dental students to learn dental English are now quite limited. The purposes of our study were to investigate: the effectiveness and feasibility of the computer-assisted simulation materials as one solution strategy for dental English education in Japan, and the needs and demands for dental English from the learners' side. Interactive simulation materials for medical interviews in English and clinical cases which were translated to English, were delivered via Learning Management System (LMS) to nineteen trainee residents of dentistry (residents). Evaluation for the materials, learners' knowledge and interests in the contents, and ease of operation were obtained by post-questionnaire (response rates were 100% and 95%, respectively). Both questionnaire-surveys received positive feedback toward the materials, yet 47% answered that they lacked the level of knowledge about contents of the medical interview in English. Results were sufficient to suggest that the residents would like to have the opportunity to study or practice medical interview in English, or English related to dentistry, and that the simulation materials could be one of the solution strategies for opportunity provision.

  14. Amalgam ablation with the Er:YAG laser

    NASA Astrophysics Data System (ADS)

    Wigdor, Harvey A.; Visuri, Steven R.; Walsh, Joseph T., Jr.

    1995-04-01

    Any laser that will be used by dentist to replace the dental drill (handpiece) must remove dental hard tissues safely. These lasers must also have the ability to ablate the restorative dental materials which are present in the teeth being treated. Prior to any laser being used to treat humans a thorough knowledge of the effects of the laser treatment on dental materials must be understood. Cores of dental amalgam were created and sliced into thin wafers for this experiment. Ablation efficiency and thermal changes were evaluated with and without water. It appears as if the Er:YAG laser can effectively ablate amalgam dental material with and without water. The water prevents the temperature from increasing much above baseline and does not reduce efficiency of ablation.

  15. Compositions of surface layers formed on amalgams in air, water, and saline.

    PubMed

    Hanawa, T; Gnade, B E; Ferracane, J L; Okabe, T; Watari, F

    1993-12-01

    The surface layers formed on both a zinc-free and a zinc-containing dental amalgam after polishing and aging in air, water, or saline, were characterized using x-ray photoelectron spectroscopy (XPS) to determine the compositions of the surface layers which might govern the release of mercury from amalgam. The XPS data revealed that the formation of the surface layer on the zinc-containing amalgam was affected by the environment in which the amalgam was polished and aged, whereas that on the zinc-free amalgam was not affected. In addition, among the elements contained in amalgam, zinc was the most reactive with the environment, and was preferentially dissolved from amalgam into water or saline. Mercury atoms existed in the metallic state in the surface layer.

  16. Wear behavior of light-cured dental composites filled with porous glass-ceramic particles.

    PubMed

    Tan, Yanni; Liu, Yong; Grover, Liam M; Huang, Baiyun

    2010-01-01

    Wear resistance is still perceived to be one of the most important limiting factors in the long-term performance of dental restorations. Consequently, a range of different materials have been used as filler particles to reduce the rate of wear, particularly in posterior restorations. In this study, novel bioactive glass-ceramic powders exhibiting different nominal calcium-mica to fluorapatite ratios were used as fillers for light-cured dental composites. Wear tests on the resulting samples were undertaken using a micro-tribometer with a linear reciprocating ball-on-flat geometry using lubrication from artificial saliva. The surfaces of the worn composites were then evaluated using optical microscopy. In order to enhance matrix bonding, the surfaces of the different particulates were treated using hydrofluoric acid to provide a porous surface and the resulting surface morphology was evaluated using scanning electron microscopy. Although in the case of the samples containing low fluorapatite contents (20 wt%; A2), surface etching enhanced the wear resistance of the composite, etching reduced the wear resistance of materials containing 50 wt% fluorapatite (A5). The reduction in wear resistance was attributed to the friability of the A5 particles following surface treatment. This suggests that in order to optimize wear resistance, it is important to find a critical balance between surface roughness and porosity and the strength of individual particles.

  17. Wear behavior of light-cured dental composites filled with porous glass-ceramic particles.

    PubMed

    Tan, Yanni; Liu, Yong; Grover, Liam M; Huang, Baiyun

    2010-01-01

    Wear resistance is still perceived to be one of the most important limiting factors in the long-term performance of dental restorations. Consequently, a range of different materials have been used as filler particles to reduce the rate of wear, particularly in posterior restorations. In this study, novel bioactive glass-ceramic powders exhibiting different nominal calcium-mica to fluorapatite ratios were used as fillers for light-cured dental composites. Wear tests on the resulting samples were undertaken using a micro-tribometer with a linear reciprocating ball-on-flat geometry using lubrication from artificial saliva. The surfaces of the worn composites were then evaluated using optical microscopy. In order to enhance matrix bonding, the surfaces of the different particulates were treated using hydrofluoric acid to provide a porous surface and the resulting surface morphology was evaluated using scanning electron microscopy. Although in the case of the samples containing low fluorapatite contents (20 wt%; A2), surface etching enhanced the wear resistance of the composite, etching reduced the wear resistance of materials containing 50 wt% fluorapatite (A5). The reduction in wear resistance was attributed to the friability of the A5 particles following surface treatment. This suggests that in order to optimize wear resistance, it is important to find a critical balance between surface roughness and porosity and the strength of individual particles. PMID:19878904

  18. 21 CFR 872.4565 - Dental hand instrument.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ..., operative dental amalgam carver, surgical bone chisel, operative amalgam and foil condenser, endodontic... finishing periodontic knife, periodontic marker, operative pliers, endodontic root canal plugger, endodontic root canal preparer, surgical biopsy punch, endodontic pulp canal reamer, crown remover,...

  19. 21 CFR 872.4565 - Dental hand instrument.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ..., operative dental amalgam carver, surgical bone chisel, operative amalgam and foil condenser, endodontic... finishing periodontic knife, periodontic marker, operative pliers, endodontic root canal plugger, endodontic root canal preparer, surgical biopsy punch, endodontic pulp canal reamer, crown remover,...

  20. Release and toxicity of dental resin composite

    PubMed Central

    Gupta, Saurabh K.; Saxena, Payal; Pant, Vandana A.; Pant, Aditya B.

    2012-01-01

    Dental resin composite that are tooth-colored materials have been considered as possible substitutes to mercury-containing silver amalgam filling. Despite the fact that dental resin composites have improved their physico-chemical properties, the concern for its intrinsic toxicity remains high. Some components of restorative composite resins are released in the oral environment initially during polymerization reaction and later due to degradation of the material. In vitro and in vivo studies have clearly identified that these components of restorative composite resins are toxic. But there is a large gap between the results published by research laboratories and clinical reports. The objective of this manuscript was to review the literature on release phenomenon as well as in vitro and in vivo toxicity of dental resin composite. Interpretation made from the recent data was also outlined. PMID:23293458

  1. Release and toxicity of dental resin composite.

    PubMed

    Gupta, Saurabh K; Saxena, Payal; Pant, Vandana A; Pant, Aditya B

    2012-09-01

    Dental resin composite that are tooth-colored materials have been considered as possible substitutes to mercury-containing silver amalgam filling. Despite the fact that dental resin composites have improved their physico-chemical properties, the concern for its intrinsic toxicity remains high. Some components of restorative composite resins are released in the oral environment initially during polymerization reaction and later due to degradation of the material. In vitro and in vivo studies have clearly identified that these components of restorative composite resins are toxic. But there is a large gap between the results published by research laboratories and clinical reports. The objective of this manuscript was to review the literature on release phenomenon as well as in vitro and in vivo toxicity of dental resin composite. Interpretation made from the recent data was also outlined.

  2. Dental material artifacts on MR images.

    PubMed

    Hinshaw, D B; Holshouser, B A; Engstrom, H I; Tjan, A H; Christiansen, E L; Catelli, W F

    1988-03-01

    Magnetic resonance (MR) imaging of the head and neck is becoming an important aid in evaluating pathologic conditions of the brain, midface, and pharynx. Certain dental materials cause artifacts during MR imaging of the lower midface. These artifacts can obscure the normal anatomy. This study describes the degree of artifact production caused by various materials commonly used in dental restorations. Of the materials tested, those causing artifacts were made of stainless steel, such as orthodontic bands used for braces, and pins or posts that are commonly drilled into teeth to provide structure or stability before filling. Materials used as temporary or permanent fillings or crowns--such as amalgam, gold alloy, aluminum, microfilled resin, and polyvinyl acrylics--did not cause artifacts in the images.

  3. The Post-Amalgam Era: Norwegian Dentists’ Experiences with Composite Resins and Repair of Defective Amalgam Restorations

    PubMed Central

    Kopperud, Simen E.; Staxrud, Frode; Espelid, Ivar; Tveit, Anne Bjørg

    2016-01-01

    Amalgam was banned as a dental restorative material in Norway in 2008 due to environmental considerations. An electronic questionnaire was sent to all dentists in the member register of the Norwegian Dental Association (NTF) one year later, to evaluate dentists’ satisfaction with alternative restorative materials and to explore dentists’ treatment choices of fractured amalgam restorations. Replies were obtained from 61.3%. Composite was the preferred restorative material among 99.1% of the dentists. Secondary caries was the most commonly reported cause of failure (72.7%), followed by restoration fractures (25.1%). Longevity of Class II restorations was estimated to be ≥10 years by 45.8% of the dentists, but 71.2% expected even better longevity if the restoration was made with amalgam. Repair using composite was suggested by 24.9% of the dentists in an amalgam restoration with a fractured cusp. Repair was more often proposed among young dentists (p < 0.01), employees in the Public Dental Service (PDS) (p < 0.01) and dentists working in counties with low dentist density (p = 0.03). There was a tendency towards choosing minimally invasive treatment among dentists who also avoided operative treatment of early approximal lesions (p < 0.01). Norwegian dentists showed positive attitudes towards composite as a restorative material. Most dentists chose minimally- or medium invasive approaches when restoring fractured amalgam restorations. PMID:27110804

  4. Three-Dimensional Human Cell Cultures for Cytotoxicity Testing of Dental Filling Materials

    PubMed Central

    Gröppl, Franziska; Hiller, Karl-Anton; Galler, Kerstin M.

    2014-01-01

    Objectives So far, bovine immortalized pulp cells have been used as three dimensional cultures for cytotoxicity testing of filling materials in the dentin barrier test (DBT). In this study, the use of human pulp-derived cells was evaluated, which would better simulate the clinical situation, and a composite material with a new resin base was tested. Materials and Methods SV40-transfected human pulp cells (tHPC) were cultured in hydrogels (fibrin, peptide, collagen) and mechanical properties and cell viability (MTT or WST-1) were determined. For cell cultures in collagen, a four week - proliferation assay was performed (WST-1). After 14 days of three-dimensional culture in collagen, tHPC were introduced into the DBT with 200 µm dentin disks. After a 24-hour incubation under perfusion (0.3 ml/h), the following materials were applied according to the manufacturers’ instructions (1) President (Coltene): negative (non-toxic) control, (2) CaGPG14 (ISO 7405): positive (toxic) control, (3) Tetric EvoCeram (Ivoclar Vivadent) with Clearfil SEBond (Kuraray, reference material), (4) N´Durance (Sepodont, test material), (5) N´Durance with Clearfil SEBond. Cell viability was determined after 24-hour incubation (WST-1). The percentage of relative viability was calculated (negative control=100%) and statistically analyzed (Kruskal-Wallis-test, p<0.05). Results Fibrin and peptide gels had insufficient mechanical properties for the DBT Collagen and appeared suitable for three-dimensional cell culture of tHPC for up to 21 days. The cultures could be transferred to the DBT device and results for controls were similar to previous tests with bovine cells. The DBT using tHPC in the collagen showed no statistically significant difference between the test material with and without the adhesive and the reference resin composite. Conclusions tHPC in collagen can replace bovine cells in the DBT. The tested filling material is not likely to cause pulp damage, if the pulp is covered by an

  5. Three-Dimensional Human Cell Cultures for Cytotoxicity Testing of Dental Filling Materials

    PubMed Central

    Gröppl, Franziska; Hiller, Karl-Anton; Galler, Kerstin M.

    2014-01-01

    Objectives So far, bovine immortalized pulp cells have been used as three dimensional cultures for cytotoxicity testing of filling materials in the dentin barrier test (DBT). In this study, the use of human pulp-derived cells was evaluated, which would better simulate the clinical situation, and a composite material with a new resin base was tested. Materials and Methods SV40-transfected human pulp cells (tHPC) were cultured in hydrogels (fibrin, peptide, collagen) and mechanical properties and cell viability (MTT or WST-1) were determined. For cell cultures in collagen, a four week - proliferation assay was performed (WST-1). After 14 days of three-dimensional culture in collagen, tHPC were introduced into the DBT with 200 µm dentin disks. After a 24-hour incubation under perfusion (0.3 ml/h), the following materials were applied according to the manufacturers’ instructions (1) President (Coltene): negative (non-toxic) control, (2) CaGPG14 (ISO 7405): positive (toxic) control, (3) Tetric EvoCeram (Ivoclar Vivadent) with Clearfil SEBond (Kuraray, reference material), (4) N´Durance (Sepodont, test material), (5) N´Durance with Clearfil SEBond. Cell viability was determined after 24-hour incubation (WST-1). The percentage of relative viability was calculated (negative control=100%) and statistically analyzed (Kruskal-Wallis-test, p<0.05). Results Fibrin and peptide gels had insufficient mechanical properties for the DBT Collagen and appeared suitable for three-dimensional cell culture of tHPC for up to 21 days. The cultures could be transferred to the DBT device and results for controls were similar to previous tests with bovine cells. The DBT using tHPC in the collagen showed no statistically significant difference between the test material with and without the adhesive and the reference resin composite. Conclusions tHPC in collagen can replace bovine cells in the DBT. The tested filling material is not likely to cause pulp damage, if the pulp is covered by an

  6. Effect of composite/amalgam thickness on fracture resistance of maxillary premolar teeth, restored with combined amalgam-composite restorations

    PubMed Central

    Firouzmandi, Maryam; Doozandeh, Maryam; Abbasi, Sanaz

    2016-01-01

    Background Combined amalgam-composite restorations have been used through many years to benefit from the advantages of both dental amalgam and composite resin. Two variations have been mentioned for this technique, this study investigated the fracture resistance of maxillary premolar teeth with extended mesio-occluso-distal (MOD) cavities, restored with the two variations of combined amalgam-composite restorations. Material and Methods Sixty intact extracted premolar teeth were randomly divided into 6 groups (G1-G6) of 10 teeth. G1; consisted of intact teeth and G2; consisted of teeth with MOD preparations were assigned as the positive and negative control groups respectively. Other experimental groups after MOD preparations were as follows: G3, amalgam restoration; G4, composite restoration; G5 combined amalgam-composite restoration with amalgam placement only on 1mm of the gingival floor of the proximal boxes; G6, combined amalgam-composite restoration with amalgam placement to the height of contact area of the proximal surface of the tooth. Fracture strength of the specimens was measured and the data were analyzed using one-way analysis of variance (ANOVA). The level of significance was P<0.05. Fracture mode of the specimens was also recorded. Results G1 had the highest value of fracture resistance (1736.90 N). G2 and G3 had the lowest fracture resistance (775.70 N and 874.70 N, respectively). The difference between G 4, 5 and 6 was not statistically significant. However, G4, G5 and G6 showed significantly higher resistance to fracture compared to G2 and G3. Fracture modes were favorable in all of the study groups except in G6. Conclusions Fracture resistance of the premolars restored with the two variations of combined amalgam-composite restoration was similar to that achieved with composite restoration alone and more than that of amalgam restoration alone. It can be concluded that the thickness of amalgam in combined amalgam-composite restorations did not

  7. 21 CFR 872.3700 - Dental mercury.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Dental mercury. 872.3700 Section 872.3700 Food and... DENTAL DEVICES Prosthetic Devices § 872.3700 Dental mercury. (a) Identification. Dental mercury is a device composed of mercury intended for use as a component of amalgam alloy in the restoration of...

  8. Mercury release of amalgams with various silver contents after exposure to bleaching agent

    PubMed Central

    Bahari, Mahmoud; Alizadeh Oskoee, Parnian; Savadi Oskoee, Siavash; Pouralibaba, Firoz; Morsali Ahari, Ali

    2016-01-01

    Background. Since it is possible for carbamide peroxide (CP) bleaching agent to contact old amalgam restorations, the present in vitro study evaluated the amount of dissolved mercury released from amalgam restorations with various percent-ages of silver content subsequent to the use of 15% CP. Methods. Thirty ANA 2000 amalgam disks with 43.1% silver content and thirty ANA 70 amalgam disks with 69.3% silver content were prepared. In each group, 15 samples were randomly placed in glass tubes containing 15% CP (as experimental groups) and the remaining 15 samples were placed in buffered phosphate solution (as control groups) with the same 3-mL volume for 48 hours. Subsequently, the amount of mercury dissolved in each test tube was measured using Mercury Analyzing System (Cold Vapor Atomic Absorption, MASLO, Shimadzu, Japan). Data was analyzed with two-way ANOVA and a post hoc Tukey test. (α = 0.05). Results. The amount of mercury released after exposure to CP was significantly higher than that released after exposure to buffered phosphate (P < 0.001). In addition, the amount of mercury released from dental amalgam with a silver content of 43% was significantly higher than that released from dental amalgam with a silver content of 69% (P < 0.001). Conclusion. The amount of mercury release is inversely proportional to the silver content of dental amalgam. PMID:27429729

  9. Mercury release of amalgams with various silver contents after exposure to bleaching agent.

    PubMed

    Bahari, Mahmoud; Alizadeh Oskoee, Parnian; Savadi Oskoee, Siavash; Pouralibaba, Firoz; Morsali Ahari, Ali

    2016-01-01

    Background. Since it is possible for carbamide peroxide (CP) bleaching agent to contact old amalgam restorations, the present in vitro study evaluated the amount of dissolved mercury released from amalgam restorations with various percent-ages of silver content subsequent to the use of 15% CP. Methods. Thirty ANA 2000 amalgam disks with 43.1% silver content and thirty ANA 70 amalgam disks with 69.3% silver content were prepared. In each group, 15 samples were randomly placed in glass tubes containing 15% CP (as experimental groups) and the remaining 15 samples were placed in buffered phosphate solution (as control groups) with the same 3-mL volume for 48 hours. Subsequently, the amount of mercury dissolved in each test tube was measured using Mercury Analyzing System (Cold Vapor Atomic Absorption, MASLO, Shimadzu, Japan). Data was analyzed with two-way ANOVA and a post hoc Tukey test. (α = 0.05). Results. The amount of mercury released after exposure to CP was significantly higher than that released after exposure to buffered phosphate (P < 0.001). In addition, the amount of mercury released from dental amalgam with a silver content of 43% was significantly higher than that released from dental amalgam with a silver content of 69% (P < 0.001). Conclusion. The amount of mercury release is inversely proportional to the silver content of dental amalgam. PMID:27429729

  10. Effects of Clinical Training and Case Difficulty on the Radiographic Quality of Root Canal Fillings Performed by Dental Students in Saudi Arabia

    PubMed Central

    Alsulaimani, Reem Siraj; Al-Manei, Kholod Khalil; A. Alsubait, Sara; AlAqeely, Razan Shafik; A. M. Al-Shehri, Sharifa; M. Al-Madi, Ebtissam

    2015-01-01

    Introduction: The aim of this study was to evaluate the effects of training duration and case difficulty on the radiographic quality of root canal fillings performed by dental students in Saudi Arabia. Methods and Materials: A longitudinal cohort study was conducted at King Saud University. Root canal treatments performed by 55 dental students from 2012-2014 were included in the study. Each student treated at least five teeth during the first year of clinical endodontic training and another five teeth during the second year. Case difficulty was assessed based on tooth position in the dental arch and preoperative conditions. The radiographic quality of the root canal filling was evaluated by two endodontists blinded to treatment completion date. The evaluation criteria were adequate obturation, presence of mishaps and preparation taper. The data were statistically analysed using univariate and multivariate logistic regression analyses; and the level of significance was set at 0.05. Results: Inadequate obturation and mishaps were significantly less prevalent in teeth treated after 2 years of clinical training. The odds ratios for inadequate obturation and mishaps increased significantly as tooth position moved posteriorly. Inadequate obturation and more mishaps were significantly more prevalent in teeth with preoperative conditions. Preparation taper was not significantly affected by training duration or case difficulty. Conclusion: The quality of root canal fillings performed by Saudi students was adversely affected by case difficulty. The radiographic quality of root canal fillings improved significantly after 2 years of clinical training. Preparation taper outcome is likely dependent on the preparation technique and instrument taper. PMID:26523143

  11. Microleakage in primary teeth restored by conventional or bonded amalgam technique.

    PubMed

    Myaki, S I; Rodrigues, C R; Raggio, D P; Flores, T A; Matson, M R

    2001-01-01

    The aim of this in vitro study was to evaluate marginal leakage in class V restorations in primary teeth restored with amalgam, using three different techniques. Thirty maxillary anterior primary teeth, clinically sound and naturally exfoliated, were used. In group 1 (n = 10), two thin layers of a copal varnish (Cavitine) were applied. In group 2 (n = 10), Scotchbond Multi-Purpose Plus, a dual adhesive system, was used according to manufacturer instructions. In group 3 (n = 10), One-Step adhesive system in combination with a low-viscosity resin (Resinomer) were used according to manufacturer instructions. All samples were restored with a high-copper dental amalgam alloy (GS 80, SDI). After restoration, the samples were stored in normal saline at 37 degrees C for 72 h. The specimens were polished, thermocycled (500 cycles, 5 degrees and 55 degrees C, 30-s dwell time) and impermeabilized with fingernail polish to within 1.0 mm of the restoration margins. The teeth were then placed in 0.5% methylene blue for 4 h. Finally, the samples were sectioned and evaluated for marginal leakage. The Kruskal-Wallis test showed that the filled adhesive resin (group 3) had the least microleakage. There was no significant difference between groups 1 and 2.

  12. VIEW, LOOKING SOUTHWEST OF GOLD AMALGAMATION ROOM, SHOWING AMALGAMATION BARREL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW, LOOKING SOUTHWEST OF GOLD AMALGAMATION ROOM, SHOWING AMALGAMATION BARREL AT CENTER FOREGROUND, BULLION FURNACE IN LARGE HOOD BEHIND IT, AND GOLD RETORT IN BACKGROUND HOOD. NOTE OVERHEAD MONORAIL FOR MATERIALS HANDLING. - Shenandoah-Dives Mill, 135 County Road 2, Silverton, San Juan County, CO

  13. Sealing ability of MTA and amalgam in different root-end preparations and resection bevel angles: an in vitro evaluation using marginal dye leakage.

    PubMed

    Post, Letícia Kirst; Lima, Fábio Garcia; Xavier, Cristina Braga; Demarco, Flávio Fernando; Gerhardt-Oliveira, Marília

    2010-01-01

    This in vitro study evaluated the effect of different apicoectomy angles, instruments used in root-end preparation, and dental materials used in retrofilling on apical sealing. Root ends were resected at 45 or 90 degrees in 80 single-rooted teeth. For each type of apicoectomy, root-end cavities were prepared with either a round carbide #2 bur or an S12/90D ultrasonic tip. The root-end cavities in each subgroup (apicoectomy + root-end preparation) were filled with silver amalgam without zinc (Am) or with gray mineral trioxide aggregate -Angelus (MTA), and the specimens were immediately immersed in 0.2% rhodamine B for 24 h. Sealing was evaluated based on the dyed cross-sectional dentin area. Data were analyzed statistically by the Kruskal-Wallis test at 5% significance level. No group showed complete sealing of root-end areas. The only significant factor affecting microleakage was dental material, with MTA exhibiting less leakage.

  14. 75 FR 33315 - Dental Products Panel of the Medical Devices Advisory Committee; Notice of Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-11

    ... received by FDA concerning the final rule on the classification of dental amalgam, which published in the... adequacy of the risk assessment performed by FDA in classifying dental amalgam in light of a new report on... HUMAN SERVICES Food and Drug Administration Dental Products Panel of the Medical Devices...

  15. Biocompatibility of dental materials used in contemporary endodontic therapy: a review. Part 2. Root-canal-filling materials.

    PubMed

    Hauman, C H J; Love, R M

    2003-03-01

    Root-canal-filling materials are either placed directly onto vital periapical tissues or may leach through dentine. The tissue response to these materials therefore becomes important and may influence the outcome of endodontic treatment. This paper is a review of the biocompatibility of contemporary orthograde and retrograde root-canal-filling materials. PMID:12657140

  16. The use of amalgam in pediatric dentistry: new insights and reappraising the tradition.

    PubMed

    Fuks, Anna B

    2015-01-01

    The debate on amalgam led to its being phased out in some countries. Results of clinical trials report failure rates of amalgams ranging from 12 percent to over 70 percent. Treatment of caries should meet the needs of each particular patient, based on his/her caries risk. In general, for small occlusal lesions, a conservative preventive resin restoration would be more appropriate than the classic Class I amalgam preparation. For proximal lesions, amalgam would be indicated for two-surface Class II preparations that do not extend beyond the line angles of primary teeth. This recommendation might not be appropriate for high-risk patients or restoring primary first molars in children four years old and younger where stainless steel crowns have demonstrated better longevity. Currently, amalgam demonstrates the best clinical success for Class II restorations that extend beyond the proximal line angles of permanent molars. The need to reduce the use of amalgam as a mercury-containing material is inevitable when aiming to reduce environmental contamination. It is important always to praise prevention and constantly search for biologically safe materials regarding health, clinical work, and environment. The purpose of this report was to summarize several factors that affect the effectiveness, advantages, and disadvantages of using dental amalgam in primary teeth.

  17. Bond strength comparison of amalgam repair protocols using resin composite in situations with and without dentin exposure.

    PubMed

    Ozcan, Mutlu; Schoonbeek, Geert; Gökçe, Bülent; Cömlekoglu, Erhan; Dündar, Mine

    2010-01-01

    The replacement of defective amalgam restorations leads to loss of tooth material and weakens the tooth, creating an increased risk of cusp fracture. The repair of such defects is a minimal intervention technique. The current study compared the repair bond strengths of a resin composite to amalgam and an amalgam-dentin complex after various surface conditioning methods. The specimens (N = 50) consisted of sound human canines with cylindrical preparations (diameter: 2.3 mm, depth: 3 mm) with amalgam-dentin complex (N = 30, n = 10/per group) and two groups with amalgam only (N = 20, n = 10/per group). The teeth were embedded in auto-polymerized polymethylmethacrylate (PMMA). The preparations were filled with non-Gamma 2 amalgam. The enamel was removed to expose dentin. The specimens with the amalgam-dentin complex were randomly assigned to one of the following conditioning methods: Group 1: Silicacoating amalgam, etching dentin, silane application on amalgam, primer/bonding on dentin, opaquer on amalgam, resin composite on both; Group 2: Etching dentin, silicacoating amalgam, silane application on amalgam, primer/bonding on dentin, opaquer on amalgam, resin composite on both and Group 3: Etching dentin, primer/bonding on dentin, opaquer, resin composite. The specimens with only amalgam were assigned to one of the following conditioning methods: Group 4: Silicacoating, silane application, opaquer, resin composite and Group 5: Opaquer, resin composite. For the two control groups, where no dentin was involved (Groups 4 and 5), bonding was achieved only on amalgam and Group 5 had no conditioning. The specimens were kept in water at 37 degrees C for five weeks before bond strength (MPa +/- SD) testing (Universal Testing Machine). After debonding, the failure types were analyzed. The results were significantly affected by the surface conditioning method (ANOVA). Only dentin conditioning (Group 3) showed the highest bond strength (39.9 +/- 14). The unconditioned control

  18. Bond strength comparison of amalgam repair protocols using resin composite in situations with and without dentin exposure.

    PubMed

    Ozcan, Mutlu; Schoonbeek, Geert; Gökçe, Bülent; Cömlekoglu, Erhan; Dündar, Mine

    2010-01-01

    The replacement of defective amalgam restorations leads to loss of tooth material and weakens the tooth, creating an increased risk of cusp fracture. The repair of such defects is a minimal intervention technique. The current study compared the repair bond strengths of a resin composite to amalgam and an amalgam-dentin complex after various surface conditioning methods. The specimens (N = 50) consisted of sound human canines with cylindrical preparations (diameter: 2.3 mm, depth: 3 mm) with amalgam-dentin complex (N = 30, n = 10/per group) and two groups with amalgam only (N = 20, n = 10/per group). The teeth were embedded in auto-polymerized polymethylmethacrylate (PMMA). The preparations were filled with non-Gamma 2 amalgam. The enamel was removed to expose dentin. The specimens with the amalgam-dentin complex were randomly assigned to one of the following conditioning methods: Group 1: Silicacoating amalgam, etching dentin, silane application on amalgam, primer/bonding on dentin, opaquer on amalgam, resin composite on both; Group 2: Etching dentin, silicacoating amalgam, silane application on amalgam, primer/bonding on dentin, opaquer on amalgam, resin composite on both and Group 3: Etching dentin, primer/bonding on dentin, opaquer, resin composite. The specimens with only amalgam were assigned to one of the following conditioning methods: Group 4: Silicacoating, silane application, opaquer, resin composite and Group 5: Opaquer, resin composite. For the two control groups, where no dentin was involved (Groups 4 and 5), bonding was achieved only on amalgam and Group 5 had no conditioning. The specimens were kept in water at 37 degrees C for five weeks before bond strength (MPa +/- SD) testing (Universal Testing Machine). After debonding, the failure types were analyzed. The results were significantly affected by the surface conditioning method (ANOVA). Only dentin conditioning (Group 3) showed the highest bond strength (39.9 +/- 14). The unconditioned control

  19. Lichenoid reaction associated with silver amalgam restoration in a Bombay blood group patient: A case report

    PubMed Central

    Pawar, Rohini Rangarao; Mattigatti, Sudha S.; Mahaparale, Rushikesh R.; Kamble, Amit P.

    2016-01-01

    The pathogenic relationship between the oral lichenoid reaction (OLR) and dental restorative materials has been confirmed many times. An OLR affecting oral mucosa in direct contact with an amalgam restoration represents a delayed, type IV, cell mediated immune response to mercury or one of the other constituents of the dental amalgam. Bombay blood group patients are more prone to this. A case of bilateral OLR is presented, which is present in relation to amalgam restoration. The lesion healed up after the replacement of restorations with an intermediate restorative material. The clinician should be aware of all the possible pathological etiologies of white lesions. If there is any doubt about the nature or management of a usual oral lesion, a referral to an appropriate specialist is mandatory. PMID:27217647

  20. Lichenoid reaction associated with silver amalgam restoration in a Bombay blood group patient: A case report.

    PubMed

    Pawar, Rohini Rangarao; Mattigatti, Sudha S; Mahaparale, Rushikesh R; Kamble, Amit P

    2016-01-01

    The pathogenic relationship between the oral lichenoid reaction (OLR) and dental restorative materials has been confirmed many times. An OLR affecting oral mucosa in direct contact with an amalgam restoration represents a delayed, type IV, cell mediated immune response to mercury or one of the other constituents of the dental amalgam. Bombay blood group patients are more prone to this. A case of bilateral OLR is presented, which is present in relation to amalgam restoration. The lesion healed up after the replacement of restorations with an intermediate restorative material. The clinician should be aware of all the possible pathological etiologies of white lesions. If there is any doubt about the nature or management of a usual oral lesion, a referral to an appropriate specialist is mandatory.

  1. Effect of restoration size on fracture resistance of bonded amalgam restorations.

    PubMed

    Lindemuth, J S; Hagge, M S; Broome, J S

    2000-01-01

    The purpose of this study was to determine the effect of restoration size on the fracture strength of amalgam restorations bonded with Amalgambond Plus (with HPA). Research has shown that this adhesive is dispersed throughout the unset amalgam during condensation and that a decrease in diametral tensile strength, proportional to the amount of adhesive incorporated into the unset amalgam, has resulted. Smaller cavity preparations have a higher ratio of surface area to volume than do larger preparations, and it was anticipated that a proportionately greater amount of adhesive would be incorporated into smaller amalgam restorations. Sixty extracted human molars were divided into four groups of 15 teeth and mounted in tray acrylic-filled PVC cylinders. Shallow approximo-occlusal channels were prepared in two groups. One group was restored with Amalgambond Plus and Tytin amalgam, the other with just Tytin amalgam. Larger proximo-occlusal preparations were made in the remaining two groups, then restored in the same fashion. Samples were stored in 37 degrees C for at least 24 hours, then thermocycled from 5-55 degrees C 1000 times with a one-minute dwell time. Specimens were mounted in a Universal Testing Machine, and a chisel was applied to the restorations in compression mode at a crosshead speed of 5.0 mm/minute until bulk fracture of the amalgam occurred. The results indicated no difference in bulk fracture strengths between large amalgam restorations restored with and without Amalgambond Plus. However, small amalgam restorations restored with Amalgambond Plus exhibited significantly greater (p < 0.025) bulk fracture strengths than small amalgam restorations restored without use of the adhesive. PMID:11203813

  2. Current Teaching of Proximal Retention Grooves for Class II Amalgam Preparations.

    ERIC Educational Resources Information Center

    Moore, David L.

    1992-01-01

    A survey gathered information on methods of class II amalgam preparation taught in 59 dental schools. Focus was on the teaching and testing of proximal retention groove use, stated rationale for placing retention grooves, and the relationship of the instruction to board criteria for cavity preparation. (MSE)

  3. Barodontalgias, dental and orofacial barotraumas: a survey in Swiss divers and caisson workers.

    PubMed

    Zanotta, Cristina; Dagassan-Berndt, Dorothea; Nussberger, Peter; Waltimo, Tuomas; Filippi, Andreas

    2014-01-01

    Changing ambient pressure can lead to medical conditions in body cavities filled with air. Intraoral pain elicited by changes in pressure is referred to as barodontalgia. Dental barotraumas are defined as pressure-induced damages of teeth and restorations. The pathophysiologic background so far is not completely clear. The present study deals with dental and orofacial symptoms which can occur as a result of pressure variations. With the aid of cantonal administrations, diving associations, and tunnel construction firms, 520 pressure-exposed individuals (499 scuba/ professional divers, 21 caisson workers operating at excess pressure) were questioned regarding dental problems. A personal interview was conducted with affected individuals. Problems in the dental area were experienced by 15% of all respondents. Toothaches were suffered by 10.2% of the participants. Tooth injuries occurred in 6.3% of all interviewees (26 fractured amalgam restorations, 4 crown fractures, 3 losses of tooth fragments). A proportion of 11.3% among the respondents complained about temporomandibular joint problems or mucosal irritations (for example aphthae) related to the mouthpieces. Barotraumas outside the dental area were incurred by 31.9% of the divers. Of these, 69.9% concerned the ears and 65.6% occurred during the descent. Based on the results obtained from the survey and taking into account the current literature, recommendations for the prevention of barotraumas in divers and caisson workers were prepared. Diagnostic exclusion of dental pathologies and avoidance of retentive reconstruction materials are important factors for the prevention of barodontalgias and dental barotraumas.

  4. Effects of the Nd:YAG laser, air-abrasion, and acid-etchant on filling materials.

    PubMed

    Türkmen, C; Sazak, H; Günday, M

    2006-01-01

    The purpose of this study was to determine any inadvertent effects of the neodymium: yttrium-aluminium-garnet (Nd:YAG) laser, air-abrasion, and ortho-phosphoric acid on some conventionally used dental filling materials [amalgam, composite resin, compomer, glass-ionomer cement (GIC), and ceromer], when they were used for purposes of margin etching and assessed according to standard enamel etching parameters using a total of five fillings. The surfaces of the filling materials were polished. One sample from each material group was exposed to laser (at 0.75 J, 15 pps) and air abrasion (with Al-oxide powder, 60 psi) for 2 s and to the 37% ortho-phosphoric acid for 60 s. The exposed materials were examined under Scanning Electron Microscopy (SEM). After laser treatment most specimens showed recrystallized areas, the GIC surface being the most affected. There were some pores and cavities on the amalgam surface following laser treatment. The abraded surfaces showed mechanical abrasions. The acid etchant showed the least effect. During the application of laser or air-abrasion, the adjacent tooth or filling surface must be protected or the dentist must be careful.

  5. Effect of rubber dam on mercury exposure during amalgam removal.

    PubMed

    Kremers, L; Halbach, S; Willruth, H; Mehl, A; Welzl, G; Wack, F X; Hickel, R; Greim, H

    1999-06-01

    It was the aim of this investigation to treat 20 volunteers with maximally 5 amalgam fillings by the same comprehensive protocol in which all removals with (n = 8) and without (n = 12) rubber dam had been performed within a few months. Nine amalgam-related parameters indicated a close matching of both groups before removal. In the group without rubber dam, mercury (Hg) levels in plasma increased significantly above preremoval values at days 1 and 3 after removal; they decreased significantly below preremoval values at day 30 in the rubber-dam group and at day 100 in both groups. Excretion rates did not increase significantly in either group, but decreased significantly at day 100 in the protected group. Peak plasma-Hg was 0.6 ng/mL on average at day one and decreased with halftimes of 3 and 43 d in subjects protected by rubber dam. The results indicated that concentrations of total mercury in plasma responded rapidly to changes in the amalgam status and reflected the actual absorption most reliably. Notably, plasma-Hg levels were sensitive enough to detect a transient attenuation of the additional exposure by using rubber dam during the removal of only a few fillings. However, being small in magnitude and lasting 100 d at best, the rubber-dam effect had minor toxicological relevance.

  6. Preservation-based approaches to restore posterior teeth with amalgam, resin or a combination of materials.

    PubMed

    Baghdadi, Ziad D

    2002-02-01

    This review is a systematic assessment, from the literature, of the status quo of dental amalgam, resin-based composite and glass-ionomer restorations for carious lesions as it applies to new concepts, coupled with clinical research. Scientifically based and practical new materials and techniques are recommended to include in contemporary practice throughout the world. Clinical and laboratory studies which have been carried out in light of modern conservative principles, and in light of the current emphasis of treating dental caries as a disease process were reviewed and discussed. An approach to managing carious lesions based upon selected advantages of dental amalgam, resin-based composite and glass-ionomer technology applied to what is termed "preservation-based" approaches to restoring teeth has been synthesized. Researched evidence contradicts the notion of "extension for prevention" in favor of maintaining sound tooth structure which would translate into more patients with healthy dentitions for entire lifetimes. PMID:12074231

  7. Bond strength of repaired amalgam restorations.

    PubMed

    Rey, Rosalia; Mondragon, Eduardo; Shen, Chiayi

    2015-01-01

    This in vitro study investigated the interfacial flexural strength (FS) of amalgam repairs and the optimal combination of repair materials and mechanical retention required for a consistent and durable repair bond. Amalgam bricks were created, each with 1 end roughened to expose a fresh surface before repair. Four groups followed separate repair protocols: group 1, bonding agent with amalgam; group 2, bonding agent with composite resin; group 3, mechanical retention (slot) with amalgam; and group 4, slot with bonding agent and amalgam. Repaired specimens were stored in artificial saliva for 1, 10, 30, 120, or 360 days before being loaded to failure in a 3-point bending test. Statistical analysis showed significant changes in median FS over time in groups 2 and 4. The effect of the repair method on the FS values after each storage period was significant for most groups except the 30-day storage groups. Amalgam-amalgam repair with adequate condensation yielded the most consistent and durable bond. An amalgam bonding agent could be beneficial when firm condensation on the repair surface cannot be achieved or when tooth structure is involved. Composite resin can be a viable option for amalgam repair in an esthetically demanding region, but proper mechanical modification of the amalgam surface and selection of the proper bonding system are essential.

  8. Bond strength of repaired amalgam restorations.

    PubMed

    Rey, Rosalia; Mondragon, Eduardo; Shen, Chiayi

    2015-01-01

    This in vitro study investigated the interfacial flexural strength (FS) of amalgam repairs and the optimal combination of repair materials and mechanical retention required for a consistent and durable repair bond. Amalgam bricks were created, each with 1 end roughened to expose a fresh surface before repair. Four groups followed separate repair protocols: group 1, bonding agent with amalgam; group 2, bonding agent with composite resin; group 3, mechanical retention (slot) with amalgam; and group 4, slot with bonding agent and amalgam. Repaired specimens were stored in artificial saliva for 1, 10, 30, 120, or 360 days before being loaded to failure in a 3-point bending test. Statistical analysis showed significant changes in median FS over time in groups 2 and 4. The effect of the repair method on the FS values after each storage period was significant for most groups except the 30-day storage groups. Amalgam-amalgam repair with adequate condensation yielded the most consistent and durable bond. An amalgam bonding agent could be beneficial when firm condensation on the repair surface cannot be achieved or when tooth structure is involved. Composite resin can be a viable option for amalgam repair in an esthetically demanding region, but proper mechanical modification of the amalgam surface and selection of the proper bonding system are essential. PMID:26325656

  9. Dental Calculus Arrest of Dental Caries

    PubMed Central

    Keyes, Paul H.; Rams, Thomas E.

    2016-01-01

    Background An inverse relationship between dental calculus mineralization and dental caries demineralization on teeth has been noted in some studies. Dental calculus may even form superficial layers over existing dental caries and arrest their progression, but this phenomenon has been only rarely documented and infrequently considered in the field of Cariology. To further assess the occurrence of dental calculus arrest of dental caries, this study evaluated a large number of extracted human teeth for the presence and location of dental caries, dental calculus, and dental plaque biofilms. Materials and methods A total of 1,200 teeth were preserved in 10% buffered formal saline, and viewed while moist by a single experienced examiner using a research stereomicroscope at 15-25× magnification. Representative teeth were sectioned and photographed, and their dental plaque biofilms subjected to gram-stain examination with light microscopy at 100× magnification. Results Dental calculus was observed on 1,140 (95%) of the extracted human teeth, and no dental carious lesions were found underlying dental calculus-covered surfaces on 1,139 of these teeth. However, dental calculus arrest of dental caries was found on one (0.54%) of 187 evaluated teeth that presented with unrestored proximal enamel caries. On the distal surface of a maxillary premolar tooth, dental calculus mineralization filled the outer surface cavitation of an incipient dental caries lesion. The dental calculus-covered carious lesion extended only slightly into enamel, and exhibited a brown pigmentation characteristic of inactive or arrested dental caries. In contrast, the tooth's mesial surface, without a superficial layer of dental calculus, had a large carious lesion going through enamel and deep into dentin. Conclusions These observations further document the potential protective effects of dental calculus mineralization against dental caries. PMID:27446993

  10. Comparison of the push-out shear bond strength of four types of glass ionomers when used to bond amalgam: An in vitro study

    PubMed Central

    Mathew, Vinod Babu; Ramachandran, S; Indira, R; Shankar, P

    2011-01-01

    Background: Dental amalgam is the primary direct posterior restorative material used worldwide, but it have certain shortcomings due to the lack of adhesiveness to the cavity. The introduction of the concept of bonded amalgam helped improve the use of amalgam as a restorative material. Aim: Evaluation of the comparative push-out shear bond strength of four types of conventional glass ionomers used to bond amalgam to tooth in simulated class I situations. Materials and Methods: Four chemical cure glass ionomers are used: GC Fuji I, GC Fuji II, GC Fuji III and GC Fuji VII, and are compared with unbonded amalgam. The push-out bond strength was tested using the Instron Universal Testing Machine at a crosshead speed of 0.5 mm/min. Statistical Analysis: One-way ANOVA and post hoc Bonferroni tests were used to analyze the data. Results: The results showed that the use of glass ionomer to bond amalgam resulted in an increase in the bond strength of amalgam. The Type VII glass ionomer showed the highest bond strength in comparison with the other glass ionomers. Conclusions: Conventional glass ionomer bonds to amalgam and shows a beneficial increase in the bond strength of the restoration in comparison with unbonded amalgam. PMID:22144798

  11. Dynamic cure measurement of dental polymer composites using optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Tomlins, Peter H.; Palin, Will M.; Shortall, Adrian C.

    2008-02-01

    Dental amalgam is being increasingly replaced by Light-activated resin-based dental composites. However, these materials are limited by inefficient setting reactions as a function of depth, constraining the maximum extent of cure and reducing biocompatibility. In this paper we demonstrate a novel metrological tool for dynamic monitoring of refractive index and thickness change through curing resins using spectral-domain optical coherence tomography. We present real-time measurements from pre- to post-cure of a series of un-filled bisphenol-A diglycidyl ether dimethacrylate (bisGMA) and triethylene glycol dimethacrylate (TEGDMA) resins with different inhibitor concentrations. Our results demonstrate that refractive index measurements are sensitive to the extent of cure of such resins and that the inhibitor concentration strongly affects the cure dynamics and final extent of cure.

  12. Amalgam hazards. An assessment of research

    SciTech Connect

    Mandel, I.D. )

    1991-08-01

    Although mercury vapor in high concentration can have deleterious effects on several organ systems, there is no evidence of risk at the levels generated by chewing with amalgam restorations. Epidemiological studies relating amalgam exposure to health outcomes are recommended, however, to provide the profession and the public a full sense of security.

  13. Amalgam Restorations: To Bond or Not.

    PubMed

    Larson, Thomas D

    2015-01-01

    This article will review the use of various liners used to eliminate microleakage in amalgam restorations. It will review the literature about whether amalgam restorations are improved by using a bonding process and if so specifically how it improves the patient outcome.

  14. Dental research at the National Bureau of Standards: how it changed the practice of dental health service.

    PubMed

    Paffenbarger, G C; Tesk, J A; Brown, W E

    1985-07-01

    A history of dental research at the National Bureau of Standards since its inception in 1919 is presented. The initial thrust on dental amalgam by the US Army Dental Corps, the assignment of Dr. William Souder to the project, and subsequent developments are traced. Difficulties in obtaining support for the early stages of the program following World War I are described. The involvement of the American Dental Association in 1928, issuance of the first ADA specification on dental amalgam, and the ultimate ramifications on dental (and medical) standards programs throughout the world are described. Benefits to patients, dentists, and taxpayers from support of the dental research program have been calculated as exceeding the combined budgets of the currently supporting institutions--NBS, ADA, and National Institute of Dental Research.

  15. An in vitro Evaluation of Microleakage of Posterior Teeth Restored with Amalgam, Composite and Zirconomer – A Stereomicroscopic Study

    PubMed Central

    Punia, Sandhya Kapoor; Bhat, Surekha; Singh, Gautam; Goyal, Pravesh; Oza, Swapnil; Raiyani, Chirag M.

    2015-01-01

    Background Numerous restorative materials are being used in dentistry to achieve adequate strength and restore aesthetics. However, a perfect ideal restorative material has still eluded dentist. Dental amalgam is versatile material with self-sealing property, but is unaesthetic. Other restorative materials like, composites require conservative preparation, but exhibits polymerisation shrinkage resulting in microleakage. To overcome these drawbacks a high strength restorative material reinforced with ceramic and zirconia fillers known as zirconomer has been introduced. The aim of this study was to evaluate the micro-leakage of these three different restorative materials. Materials and Methods Thirty non-carious human permanent first and second molars were utilized in this study. Class I cavities were prepared on the occlusal surface; cavities were then restored with amalgam, composite and zirconomer as per manufacture’s instruction. All samples were stored for 24 hours in distilled water followed by thermocycling. The entire tooth surface was painted with two coats of varnish to within 1mm of the restoration margins. The teeth were immersed in dye. Teeth were sectioned and observed under stereomicroscope. Results In this study the zirconomer exhibited the highest micro leakage as compared to composite and amalgam but composite having higher micro leakage as compared to amalgam and lower micro leakage as compared to zirconomer. Conclusion Even though composite and amalgam are being marketed aggressively and new material like zirconomer are on origin, amalgam still proves to be one of the best materials. PMID:26393208

  16. The effect of 3 T MRI on microleakage of amalgam restorations

    PubMed Central

    Yilmaz, S; Misirlioğlu, M

    2013-01-01

    Objectives: To evaluate the effects of 3 T magnetic field on microleakage of amalgam restorations containing three different types of silver (Ag). Methods: 60 extracted teeth were restored with three different types of amalgam filling materials. Restored teeth were sectioned mesiodistally and divided into experimental and control groups. Experimental groups were exposed to a magnetic field of 3 T for 20 min. All samples were plunged into 2% basic fuchsin solution and examined under a digital microscope by three different observers with regard to microleakage. Results: Statistical analysis showed significant differences in microleakage between the groups exposed to MRI and controls, whereas differences in microleakage between amalgam types were insignificant. Conclusions: The primary risk of MRI systems arises from the effects of its strong magnetic field on objects containing ferromagnetic materials. An MRI of 1.5 T is known to be safe for amalgam restorations. However, our research indicates that MRI is not completely devoid of any effects on amalgam restorations. PMID:23674614

  17. Factors affecting the placement or replacement of direct restorations in a dental school

    PubMed Central

    Silvani, Samara; Trivelato, Roberta Ferreira; Nogueira, Ruchele Dias; Gonçalves, Luciano de Souza; Geraldo-Martins, Vinícius Rangel

    2014-01-01

    Context: The knowledge of the reasons for the placement of direct restorations makes possible to trace an epidemiological profile of a specific population and to direct the teaching of dentistry to techniques that are commonly used today and will be continued performed in the future. Purpose: The aim of this study was to verify the reasons for placement and replacement of direct restorations in patients treated in the Dental Clinic of the Uberaba University – Brazil. Materials and Methods: This study evaluated 306 restorative procedures carried out on 60 patients. During the treatment planning, a form that contained information about the patient's gender, tooth number, the classification of restorations, the reasons for placement and replacement of amalgam and tooth-colored restorations, the material that had to be removed and the new material used to fill the cavities was filled for each patient. Statistical analysis was carried out using Chi-square test (α = 0.05). Results: The data showed that most of the patients were female (66.7%). Of all the restorations placed, 60.45% were 1st-time placements, while 39.55% were replacements. For 1st-time restorations, the main reason for placement was primary caries (76.76%), followed by non-carious cervical lesions (15.14%). The amalgam restorations were replaced more frequently (67.77%). The primary reason for replacements was the presence of secondary caries (for both previous amalgam (42.68%) and composite (66.67%) restorations (P < 0.05). The resin composite was the most indicated material for the new restorations (98.04%) (P < 0.05). Conclusions: The main reason for placement of direct restorations was primary caries, while secondary caries was the main reason for replacements. In almost all cases, the material used to fill the cavities was the resin composite. PMID:24808696

  18. Radiochemical separation of gold by amalgam exchange

    USGS Publications Warehouse

    Ruch, R.R.

    1970-01-01

    A rapid and simple method for the radiochemical separation of gold after neutron activation. The technique is based on treatment with a dilute indium-gold amalgam, both chemical reduction and isotopic exchange being involved. The counting efficiency for 198Au in small volumes of the amalgam is good. Few interferences occur and the method is applicable to clays, rocks, salts and metals. The possibility of determining silver, platinum and palladium by a similar method is mentioned. ?? 1970.

  19. On modeling and nanoanalysis of caries-affected dentin surfaces restored with Zn-containing amalgam and in vitro oral function.

    PubMed

    Toledano, Manuel; Aguilera, Fátima S; Osorio, Estrella; López-López, Modesto T; Cabello, Inmaculada; Toledano-Osorio, Manuel; Osorio, Raquel

    2015-01-01

    The aim of this research was to assess the influence of mechanical loading on the ability of Zn-free versus Zn-containing amalgams to promote remineralization at the dentin interface. Sound and caries-affected dentin surfaces (CAD) were restored using Zn-free or Zn-containing dental amalgams. Midcoronal dentin surfaces were studied by (1) atomic force microscopy analysis (including plot and phase imaging, nanoindentation test [modulus of Young (Ei), nanoroughness measurements, and fibril diameter assessment], (2) Raman spectroscopy/cluster analysis, (3) x-ray diffraction, (4) field emission electron microscope and energy-dispersive analysis, for morphological, mechanical, and physicochemical characterization. Analyses were performed before amalgam placement and after amalgam removal, at 24 h and 3 weeks of load cycling. Zn-free and Zn-containing amalgams restorations promoted an increase in the modulus of Young of CAD surfaces, after 3 weeks of load cycling; at this time, Zn-containing amalgams attained higher Ei than Zn-free restorations. Zn-containing amalgams induced tubular occlusion after load cycling, in both sound and CAD. Zn free-amalgams promoted remineralization of both intertubular and peritubular dentin in CAD substrata. These minerals were identified as calcium-phosphate deposits and crystals as hydroxyl-apatite with augmented crystallographic maturity but with some components of lattice distortion. Crosslinking of collagen diminished and secondary structure of collagen increased in CAD substrate restored with Zn-containing amalgam after 3 weeks of load cycling, indicating an advanced preservation, molecular organization, and orientation of collagen fibrils after load cycling. Plot and phase images permitted to observe the topographical changes which were promoted by the mineral deposits; in general, the indexes related to higher remineralization gave rise to a decrease of nanoroughness and an augmentation of the bandwidth of the collagen fibrils. Zn

  20. Utility of Megavoltage Fan-Beam CT for Treatment Planning in a Head-And-Neck Cancer Patient with Extensive Dental Fillings Undergoing Helical Tomotherapy

    SciTech Connect

    Yang, Claus; Liu Tianxiao; Jennelle, Richard L.; Ryu, Janice K.; Vijayakumar, Srinivasan; Purdy, James A.; Chen, Allen M.

    2010-07-01

    The purpose of this study was to demonstrate the potential utility of megavoltage fan-beam computed tomography (MV-FBCT) for treatment planning in a patient undergoing helical tomotherapy for nasopharyngeal carcinoma in the presence of extensive dental artifact. A 28-year-old female with locally advanced nasopharyngeal carcinoma presented for radiation therapy. Due to the extensiveness of the dental artifact present in the oral cavity kV-CT scan acquired at simulation, which made treatment planning impossible on tomotherapy planning system, MV-FBCT imaging was obtained using the HI-ART tomotherapy treatment machine, with the patient in the treatment position, and this information was registered with her original kV-CT scan for the purposes of structure delineation, dose calculation, and treatment planning. To validate the feasibility of the MV-FBCT-generated treatment plan, an electron density CT phantom (model 465, Gammex Inc., Middleton, WI) was scanned using MV-FBCT to obtain CT number to density table. Additionally, both a 'cheese' phantom (which came with the tomotherapy treatment machine) with 2 inserted ion chambers and a generic phantom called Quasar phantom (Modus Medical Devices Inc., London, ON, Canada) with one inserted chamber were used to confirm dosimetric accuracy. The MV-FBCT could be used to clearly visualize anatomy in the region of the dental artifact and provide sufficient soft-tissue contrast to assist in the delineation of normal tissue structures and fat planes. With the elimination of the dental artifact, the MV-FBCT images allowed more accurate dose calculation by the tomotherapy system. It was confirmed that the phantom material density was determined correctly by the tomotherapy MV-FBCT number to density table. The ion chamber measurements agreed with the calculations from the MV-FBCT generated phantom plan within 2%. MV-FBCT may be useful in radiation treatment planning for nasopharyngeal cancer patients in the setting of extensive

  1. Shear bond strength, failure modes, and confocal microscopy of bonded amalgam restorations.

    PubMed

    Cianconi, Luigi; Conte, Gabriele; Mancini, Manuele

    2011-01-01

    This study evaluated the shear bond strength, failure modes, and confocal microscopy of two different amalgam alloy restorations lined with five adhesive systems. Two regular-set high-copper dental amalgam alloys, Amalcap Plus and Valiant Ph.D, and five commercially available adhesive systems were selected. One hundred and twenty freshly-extracted human third molars were used for the study. The results were statistically evaluated using two-factor analysis of variance (ANOVA). The shear bond strength (SBS) of amalgam to dentin was significantly affected by both the adhesive (p<0.0001) and amalgam alloy (p<0.0002). Regarding mode of failure (MF), among samples restored with Valiant Ph.D, 31 of 50 exhibited adhesive failure, and 19 displayed mixed failure. Laser optical microscopy (OM) of the bonded interface revealed the presence of a good hybrid layer was evident in all experimental groups. Higher bond strengths were measured for four of the five adhesives when used in combination with the spherical alloy. PMID:21383518

  2. Barodontalgias, dental and orofacial barotraumas: a survey in Swiss divers and caisson workers.

    PubMed

    Zanotta, Cristina; Dagassan-Berndt, Dorothea; Nussberger, Peter; Waltimo, Tuomas; Filippi, Andreas

    2014-01-01

    Changing ambient pressure can lead to medical conditions in body cavities filled with air. Intraoral pain elicited by changes in pressure is referred to as barodontalgia. Dental barotraumas are defined as pressure-induced damages of teeth and restorations. The pathophysiologic background so far is not completely clear. The present study deals with dental and orofacial symptoms which can occur as a result of pressure variations. With the aid of cantonal administrations, diving associations, and tunnel construction firms, 520 pressure-exposed individuals (499 scuba/ professional divers, 21 caisson workers operating at excess pressure) were questioned regarding dental problems. A personal interview was conducted with affected individuals. Problems in the dental area were experienced by 15% of all respondents. Toothaches were suffered by 10.2% of the participants. Tooth injuries occurred in 6.3% of all interviewees (26 fractured amalgam restorations, 4 crown fractures, 3 losses of tooth fragments). A proportion of 11.3% among the respondents complained about temporomandibular joint problems or mucosal irritations (for example aphthae) related to the mouthpieces. Barotraumas outside the dental area were incurred by 31.9% of the divers. Of these, 69.9% concerned the ears and 65.6% occurred during the descent. Based on the results obtained from the survey and taking into account the current literature, recommendations for the prevention of barotraumas in divers and caisson workers were prepared. Diagnostic exclusion of dental pathologies and avoidance of retentive reconstruction materials are important factors for the prevention of barodontalgias and dental barotraumas. PMID:24853026

  3. Progression of radiopacities and radiolucencies under amalgam restorations on bite-wing radiographs.

    PubMed

    Rudolphy, M P; Gorter, Y; van Loveren, C; Poorterman, J H; van Amerongen, J P

    1997-01-01

    Radiolucent and radiopaque areas in the dentine under amalgam fillings represent demineralized tissue. The aim of this study was to investigate whether caries progresses in radiolucent and radiopaque areas under amalgam fillings, by assessing their enlargement longitudinally on bite-wing radiographs. Bite-wings from dentitions of persons aged 17, 20 and 23 years were compared. For a 3-year evaluation, 365 teeth with class I and class II amalgam restorations were available on bite-wings; 16 radiopacities, 46 radiolucencies and 28 combinations could be followed longitudinally. All radiopacities remained the same size, 14 radiolucencies enlarged and 8 combinations enlarged. For a 6-year evaluation, 236 filled teeth were available; 10 radiopacities, 30 radiolucencies and 11 combinations could be compared longitudinally. All radiopacities remained the same size, 12 radiolucencies enlarged and 6 combinations enlarged. Because the radiopaque areas had not enlarged visibly on bite-wing radiographs over 3 or even 6 years, it was concluded that radiopacities may be non-progressing caries. A substantial number of radiolucent areas, with or without concomitant radiopacities, did not enlarge while radiolucent areas are considered as progressing caries.

  4. Radiochemical separation of gallium by amalgam exchange

    USGS Publications Warehouse

    Ruch, R.R.

    1969-01-01

    An amalgam-exchange separation of radioactive gallium from a number of interfering radioisotopes has been developed. A dilute (ca. 0.3%) gallium amalgam is agitated with a slightly acidic solution of 72Ga3+ containing concentrations of sodium thiocyanate and either perchlorate or chloride. The amalgam is then removed and the radioactive gallium stripped by agitation with dilute nitric acid. The combined exchange yield of the perchlorate-thiocyanate system is 90??4% and that of the chloride-thiocyanate system is 75??4%. Decontamination yields of most of the 11 interfering isotopes studied were less than 0.02%. The technique is applicable for use with activation analysis for the determination of trace amounts of gallium. ?? 1969.

  5. Costing dental restorations in public sector dental clinics.

    PubMed

    Khairiyah, Abdul Muttalib; Razak, Ishak Abdul; Raja-Latifah, Raja Jalludin; Tan, Bee Siew; Norain, Abu Talib; Noor-Aliyah, Ismail; Natifah, Che Salleh; Rauzi, Ismail

    2009-04-01

    The objective of this study is to share cost analysis methodology and to obtain cost estimates for posterior restorations in public sector dental clinics. Two urban and 2 rural dental clinics in Selangor state were selected. Only cases of 1 posterior restoration per visit by dental officers were included over 6 months. One capsulated amalgam type, 1 capsulated tooth-colored, and 1 non-capsulated tooth-colored material were selected. A clinical pathway form was formulated to collect data per patient. Annual capital and recurrent expenditures were collected per clinic. The mean cost of an amalgam restoration was RM 30.96 (sdRM 7.86); and tooth-colored restorations ranged from RM 33.00 (sdRM 8.43) to RM 41.10 (sdRM 10.61). Wherein 1 USD = RM 2.8. Restoration costs were 35% to 55% higher in clinics in rural areas than in urban areas. The findings demonstrate economy of scale for clinic operation and restoration costs with higher patient load. Costs per restoration were higher in rural than in urban dental clinics. More studies are recommended to address the dearth of dental costs data in Malaysia.

  6. Bonded amalgam sealants: two-year clinical results.

    PubMed

    Staninec, M; Eakle, W S; Silverstein, S; Marshall, G W; Artiga, N

    1998-03-01

    The authors used bonded amalgams as pit and fissure sealants without mechanical preparation. They compared the two-year retention of the bonded amalgams with that of resin-based pit and fissure sealants. Clinical examinations at six months, one year and two years revealed no difference between the retention of the two sealants. This technique opens up the possibility of using bonded amalgam in pits and fissures surrounding very conservative preparations in a preventive amalgam restoration. PMID:9529807

  7. Composite veneering of complex amalgam restorations.

    PubMed

    Demarco, Flávio Fernando; Zanchi, César Henrique; Bueno, Márcia; Piva, Evandro

    2007-01-01

    In large posterior cavities, indirect restorations could provide improved performance when compared to direct restorations, but with higher cost and removal of sound tooth structure. Improved mechanical properties have resulted in good clinical performance for amalgam in large cavities but without an esthetic appearance. Resin composites have become popular for posterior restorations, mainly because of good esthetic results. A restorative technique is presented that combines the esthetic properties of directly bonded resin composite and the wide range of indications for amalgam in stress-bearing areas.

  8. Novel Amalgams for In-Space Parts Fabrication

    NASA Technical Reports Server (NTRS)

    Cochran, Calvin; VanHoose, James R.; Grugel, Richard N.

    2012-01-01

    Sound amalgams can be fabricated by substituting Ga-In liquid for mercury; Cu-coated steel fibers bond well with the amalgam components. Inclusion of steel fibers significantly improved mechanical properties. An application scenario utilizing amalgams for in-space parts fabrication and repair was suggested. Procedure and materials need to be optimized

  9. Prevalence of dental caries in dentistry students.

    PubMed

    Pavleova, G; Vesela, S; Stanko, P

    2015-01-01

    The study evaluates dental caries prevalence in dentistry students. They represent a sample of individuals with good dental status, socio-economical level and access to dental care. The values of teeth number with decay and filling and values of surfaces of teeth with decay and filling indices in group with lower caries incidence give the information as to what could be achieved by systemic care and prevention of dental caries in whole population (Tab. 4. Ref. 25).

  10. Effects of high temperature on different restorations in forensic identification: Dental samples and mandible

    PubMed Central

    Patidar, Kalpana A; Parwani, Rajkumar; Wanjari, Sangeeta

    2010-01-01

    Introduction: The forensic odontologist strives to utilize the charred human dentition throughout each stage of dental evaluation, and restorations are as unique as fingerprints and their radiographic morphology as well as the types of filling materials are often the main feature for identification. The knowledge of detecting residual restorative material and composition of unrecovered adjacent restoration is a valuable tool-mark in the presumptive identification of the dentition of a burned victim. Gold, silver amalgam, silicate restoration, and so on, have a different resistance to prolonged high temperature, therefore, the identification of burned bodies can be correlated with adequate qualities and quantities of the traces. Most of the dental examination relies heavily on the presence of the restoration as well as the relationship of one dental structure to another. This greatly narrows the research for the final identification that is based on postmortem data. Aim: The purpose of this study is to examine the resistance of teeth and different restorative materials, and the mandible, to variable temperature and duration, for the purpose of identification. Materials and Methods: The study was conducted on 72 extracted teeth which were divided into six goups of 12 teeth each based on the type of restorative material. (Group 1 - unrestored teeth, group 2 - teeth restored with Zn3(PO4)2, group 3 - with silver amalgam, group 4 with glass ionomer cement, group 5 - Ni-Cr-metal crown, group 6 - metal ceramic crown) and two specimens of the mandible. The effect of incineration at 400°C (5 mins, 15 mins, 30 mins) and 1100°C (15 mins) was studied. Results: Damage to the teeth subjected to variable temperatures and time can be categorized as intact (no damage), scorched (superficially parched and discolored), charred (reduced to carbon by incomplete combustion) and incinerated (burned to ashes). PMID:21189989

  11. Improvement of Cheilitis granulomatosa after Dental Treatment.

    PubMed

    Sasaki, Ryosuke; Suzuki, Kayoko; Hayashi, Teppei; Inasaka, Hiroshi; Matsunaga, Kayoko

    2011-05-01

    A 38-year-old male suffered from swelling of the lower lip for 3 months. Neither facial nerve palsy nor fissuring of the tongue was present. Histological examination of a biopsy taken from the lower lip revealed non-caseous epithelioid cell granulomas, suggestive of cheilitis granulomatosa. Patch testing revealed positive reactions to mercury chloride and amalgam. His symptoms markedly improved 3 months after treatment of the apical periodontitis and replacement of dental crowns. As his dental crowns did not contain mercury, we believe that the cheilitis granulomatosa may have been related to the focal dental infection. PMID:21941479

  12. Scalp Hair and Urine Mercury Content of Children in the Northeast United States: The New England Children’s Amalgam Trial

    PubMed Central

    Dunn, Julie E.; Trachtenberg, Felicia L.; Barregard, Lars; Bellinger, David; McKinlay, Sonja

    2008-01-01

    Children may be at particular risk from toxic effects of mercury (Hg). Previous studies of hair (organic) and urine (inorganic) Hg levels in US children were unable to assess Hg levels while accounting for exposure to amalgam dental restorations. This analysis describes, over a 5-year period, levels and correlates/predictors of scalp hair (H-Hg) and urinary (U-Hg) mercury in 534 New England Children’s Amalgam Trial (NECAT) participants, aged 6–10 years and without exposure to dental amalgam at baseline. Results: Mean H-Hg levels were between 0.3 and 0.4 μg/g over 5 years. 17–29% of children had H-Hg levels ≥0.5μg/g, and 5.0 to 8.5% of children had levels ≥1μg/g, in any given study year. In adjusted models, fish consumption frequency was the most robust predictor of high H-Hg. U-Hg mean levels were between 0.7 to 0.9 μg/g creatinine over two years. The percentage of those with U-Hg≥2.3μg/g creatinine ranged from 4 to 6%. Number of amalgam restorations had a significant dose-response relationship with U-Hg level. Daily gum chewing in the presence of amalgam was associated with high U-Hg. PMID:17961541

  13. The release, tissue distribution and excretion of mercury from experimental amalgam tattoos.

    PubMed Central

    Cox, S. W.; Eley, B. M.

    1986-01-01

    Following the subcutaneous implantation of powdered dental amalgam in guinea pigs, there was an initial extrusion of material from the healing implantation wounds. Longer-term release of mercury from the lesions was demonstrated by linear regression analysis of the mercury contents of implant sites removed after time periods of up to 2 years. Raised mercury levels were detected in the blood, bile, kidneys, liver, spleen and lungs of implanted animals; by far the highest concentrations were found in the renal cortex. Mercury was excreted with the urine and, to a lesser extent, the faeces. The pattern of mercury redistribution resembled that seen following chronic exposure to mercuric compounds. PMID:3801303

  14. 21 CFR 872.3820 - Root canal filling resin.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3820 Root canal filling resin. (a) Identification... for use during endodontic therapy to fill the root canal of a tooth. (b) Classification. (1) Class...

  15. Reaction of the dental pulp to hydroxyapatite.

    PubMed

    Jaber, L; Mascrès, C; Donohue, W B

    1992-01-01

    The purpose of this study was to evaluate the action of hydroxyapatite (HA) (Osteogen HA Resorb, GBD Marketing Group Inc., Valley Stream, N.Y.) on the dental pulp of rats. Four upper molar pulps in 45 rats were exposed and capped with synthetic HA (Osteogen) with a stereoscopic microscope. Pulps capped with calcium hydroxide (Dycal, L.D. Caulk Co., Milford, Del.) served as controls. The cavities were filled with amalgam, and the molars on each side of the maxilla were protected by the placement of a pedodontic steel crown. Pulp inflammation and dentin repair were compared by histologic observations and computer image analysis after 7, 14, and 28 days. After 7 days a partial acute pulpitis were observed in specimens treated with Osteogen or Dycal. Reparative dentin formation along the pulp walls was also seen. After 14 days the pulpitis was more extensive in the Osteogen-treated teeth than in the control teeth. Dentin formation as measured by morphometric analysis was more pronounced in Osteogen-treated teeth. Neo-odontoblasts were observed after the use of both materials. After 28 days an acute inflammatory reaction was still evident in the Osteogen-treated group. A complete dentinal bridge was observed more frequently with Dycal than with Osteogen. Despite the putative abilities of HA to be osteoconductive, osteogenic, and dentinogenic, the results of this study indicate that it should not be used as a pulp-capping agent because of its tendency to cause scattered dystrophic calcification in the dental pulp, which could interfere with future endodontic treatment. PMID:1318535

  16. [Coronal filling biomaterials. Criteria for selection].

    PubMed

    Degrange, M

    1990-01-01

    The aim of this paper is to assess filling biomaterials according to specification criteria, the foremost of which is the respective ability of each to form a tight seal along cavity walls. Their direct or indirect (cementing or bonding) adhesive potential is the determining factor in their durability and the biocompatibility of the restoration achieved. Gold inlay alloys and amalgams appear as yet to be the most reliable and well-tolerated biomaterials for posterior restorations. For filling small cavities in the anterior sector, microfilled composites are clearly indicated; bonded porcelain, while not yet validated over time, would seem to be a good alternative for more extensive restorations.

  17. Oral health status, dental anxiety, and behavior-management problems in children with oppositional defiant disorder.

    PubMed

    Aminabadi, Naser A; Najafpour, Ebrahim; Erfanparast, Leila; Jamali, Zahra; Pournaghi-Azar, Fatemeh; Tamjid-Shabestari, Shabnam; Shirazi, Sajjad

    2016-02-01

    Mental disorders have been shown to affect children's oral health. This study was carried out to investigate the oral health status, dental anxiety (DA), and behavior-management problems (BMPs) during dental treatment in 6- to 9-yr-old children with oppositional defiant disorder (ODD)/attention-deficit hyperactivity disorder (ADHD). The study and control groups included 40 children with ODD/ADHD and 80 normal children, respectively. All participants received an amalgam restoration. During the procedure, the children's behavior was assessed using the Frankl Rating Scale and the Verbal Skill Scale. Parents rated their children's DA using the parental version of the Children's Fear Survey Schedule-Dental subscale (CFSS-DS). Comorbid anxiety disorders were assessed using the Kiddie-Sads-Present and Lifetime Version questionnaire. Oral health status was assessed using the gingival index and the decayed, missing, and filled teeth score for permanent (DMFT) and primary (dmft) teeth. The findings showed that DA and BMPs were significantly higher in children with ODD/ADHD than in the controls. Furthermore, the frequency of DA and BMPs was higher in children with both ODD/ADHD and a comorbid anxiety disorder than in those without comorbid anxiety disorder. Children with ODD/ADHD had significantly higher DMFT/dmft scores than those in the control group, whereas the difference in gingival index was not statistically significant. In conclusion, children with ODD/ADHD had higher levels of DA, BMP and poorer oral health status. PMID:26707341

  18. Oral health status, dental anxiety, and behavior-management problems in children with oppositional defiant disorder.

    PubMed

    Aminabadi, Naser A; Najafpour, Ebrahim; Erfanparast, Leila; Jamali, Zahra; Pournaghi-Azar, Fatemeh; Tamjid-Shabestari, Shabnam; Shirazi, Sajjad

    2016-02-01

    Mental disorders have been shown to affect children's oral health. This study was carried out to investigate the oral health status, dental anxiety (DA), and behavior-management problems (BMPs) during dental treatment in 6- to 9-yr-old children with oppositional defiant disorder (ODD)/attention-deficit hyperactivity disorder (ADHD). The study and control groups included 40 children with ODD/ADHD and 80 normal children, respectively. All participants received an amalgam restoration. During the procedure, the children's behavior was assessed using the Frankl Rating Scale and the Verbal Skill Scale. Parents rated their children's DA using the parental version of the Children's Fear Survey Schedule-Dental subscale (CFSS-DS). Comorbid anxiety disorders were assessed using the Kiddie-Sads-Present and Lifetime Version questionnaire. Oral health status was assessed using the gingival index and the decayed, missing, and filled teeth score for permanent (DMFT) and primary (dmft) teeth. The findings showed that DA and BMPs were significantly higher in children with ODD/ADHD than in the controls. Furthermore, the frequency of DA and BMPs was higher in children with both ODD/ADHD and a comorbid anxiety disorder than in those without comorbid anxiety disorder. Children with ODD/ADHD had significantly higher DMFT/dmft scores than those in the control group, whereas the difference in gingival index was not statistically significant. In conclusion, children with ODD/ADHD had higher levels of DA, BMP and poorer oral health status.

  19. Ablation by-products of dental materials from the Er:YAG laser and the dental handpiece

    NASA Astrophysics Data System (ADS)

    Wigdor, Harvey A.; Visuri, Steven R.; Walsh, Joseph T., Jr.

    1995-05-01

    Recently there has been much interest in lasers and their potential use to replace the dental drill. The research has been directed towards vital dental tissues. It must be understood that any laser to be used in dentistry which will replace the dental drill must also ablate and remove existing dental materials. Some concern exists about the ablation products when the Er:YAG laser is used to ablate dental materials. It is incumbent on the professionals using these lasers to understand the materials being produced by these lasers and protect themselves and their patients from possible toxic products. It is the intent of this paper to evaluate the products produced by the ablation of both dental amalgam and composite dental restorative materials and compare them with those produced by the traditional dental handpiece (drill).

  20. [Microleakage of four different amalgam binding systems].

    PubMed

    Oberholzer, T G; Grobler, S R; Rossouw, R J; van Wyk Kotze, T J; Grobler-Rabie, A

    2001-02-01

    This-study was undertaken to evaluate and compare microleakage in class V cavities in human teeth which were lined with Amalgambond Plus with HPA (Parkell, USA), Optibond Solo (Kerr, U.S.A.), Fuji Plus (GC Corporation, Japan) and Prime & Bond 2.1 (Dentsply, Switzerland), and then restored with Logic amalgam (SDI Australia). The restored teeth were thermocycled in basic fuchsin dye, sectioned, and evaluated for dye penetration. The interdiffusion zones were viewed in a confocal laser scanning microscope (CLSM). The results showed that no bonding system could totally eliminate microleakage. Statistical analysis revealed significant differences between Amalgambond Plus with HPA and Prime & Bond 2.1, Fuji Plus as well as Optibond Solo, for both the enamel and dentine sides. No significant differences were found between Prime & Bond 2.1, Fuji Plus and Optibond Solo, for both the enamel and dentine sides. Amalgambond Plus showed significantly more leakage at dentine sides while Prime & Bond 2.1 showed significantly more leakage at enamel sides. The CLSM revealed hybrid layers of different thicknesses, resin penetration into tubules, as well as resin incorporation within the spherical particles of the amalgam. Optibond Solo, Fuji Plus and Prime & Bond 2.1 can serve to improve the marginal seal of amalgam restorations.

  1. Cusp reinforcement by bonding of amalgam restorations.

    PubMed

    Pilo, R; Brosh, T; Chweidan, H

    1998-01-01

    The purpose of the present study was to assess the effectivenes of several adhesives in bonding amalgam in order to recover tooth stiffness. A non-destructive experimental methodology was adopted, using strain gauges bonded to the midbuccal surfaces of 40 teeth, with sequential evaluation of loaded intact, prepared and restored stages of the same tooth. Continuous strain measurement as a function of the applied load was acquired by A/D equipment and a data acquisition programme. The strain-force behaviour of the sound teeth under non-axial force up to 97.5 N served as the baseline. The five experimental groups (8 x 5) consisted of control (no adhesive) and four different adhesives. One-way analysis of variance with repeated measures was calculated for the deformation ratio, relative stiffness and recovery values. Reductions in tooth structure by cutting a mesio-occlusal-distal preparation, width one-third intercuspal distance, resulted in 39-52% loss of buccal cusp stiffness. Non-bonded amalgam produced negligible increase (5%) in the stiffness recovery values of the buccal cusps. The adhesives splinted the cusps together, thereby decreasing cuspal flexure and increasing relative stiffness values. Recovery values obtained ranged from 39% to 61%. Assuming that cusp fracture occurs as a result of brittle tooth structure fatigue, amalgam adhesives may contribute to the strengthening of weakened cusps.

  2. METHOD AND APPARATUS FOR DETERMINING AMALGAM DECOMPOSITION RATE

    DOEpatents

    Johnson, R.W.; Wright, C.C.

    1962-04-24

    A method and apparatus for measuring the rate at which an amalgam decomposes in contact with aqueous solutions are described. The amalgam and an aqueous hydroxide solution are disposed in an electrolytic cell. The amalgam is used as the cathode of the cell, and an electrode and anode are disposed in the aqueous solution. A variable source of plating potential is connected across the cell. The difference in voltage between the amalgam cathode and a calibrated source of reference potential is used to control the variable source to null the difference in voltage and at the same time to maintain the concentration of the amalgam at some predetermined constant value. The value of the current required to maintain this concentration constant is indicative of the decomposition rate of the amalgam. (AEC)

  3. Mercury burden and health impairment in dental auxilaries. Final report

    SciTech Connect

    Shapiro, I.M.; Bloch, P.; Ship, I.I.; Spitz, L.; Summer, A.

    1988-01-01

    An effort was made to develop a safe and effective x-ray fluorescence system for monitoring mercury and other elements in human tissues in-situ, to determine mercury levels in 207 dental auxiliaries exposed to dental amalgam on the job, to evaluate mercury in matching nonexposed populations and in 298 dentists using mercury amalgam, and to evaluate deficiencies in central and peripheral nervous systems resulting from the mercury exposure. Mercury levels were below 20 micrograms/gram in 60% of the dentists and 90% of the dental auxiliaries. Dentists with the higher mercury concentrations in their heads or wrists had considerably longer median motor distal latencies and median F-wave latency. Five of them demonstrated abnormalities consistent with carpal tunnel syndrome; seven had polyneuropathies defined as reduced motor or sensory conduction velocities of response amplitudes in two or more nerves. Neuropsychological tests indicated both groups of dental workers were adversely affected by mercury exposure.

  4. Early struggles to identify ethical standards in dentistry: Dr. Benjamin Brown and the amalgam war of the 1840s.

    PubMed

    Meyerhof, Peter G

    2007-01-01

    Dr. Benjamin Boyer Brown was one of the leading physicians and dentists in St. Louis during the 1830s and 1840s as well as one of its most esteemed citizens for his charitable and educational works. He was also one of the founders of organized dentistry, first editor of the Dental Register of the West, as well as a respected researcher and educator in dentistry, and a member of the American Society of Dental Surgery, a forerunner of the American Dental Association. This society, declared the use of amalgam to be not only unethical but malpractice, and members were forced to sign a pledge not to use it. Although many dentists opposed this decision and ignored the pledge altogether, Dr. Brown was morally unwilling to remain quiet. He vocally opposed the decision of his colleagues to ban amalgam on ethical grounds. In spite of his appeal for reason and his high profile, he was one of the few dentists to be expelled from organized dentistry. He moved to California during the height of the gold rush to begin a new life. Dr. Brown's experience illustrates several issues in dental ethics that remain with us today.

  5. 48. INTERIOR VIEW FROM THE WEST END OF THE AMALGAMATION ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    48. INTERIOR VIEW FROM THE WEST END OF THE AMALGAMATION TABLES LOOKING NORTH TOWARDS THE STAMP BATTERIES WITH AMALGAM TRAPS SHOWN IN THE BOTTOM FOREGROUND. NOTE THE EXTANT EQUIPMENT IN THE FOREGROUND THAT THE PARK USES TO INTERPRET THE MILL. FROM LEFT TO RIGHT, A SCREEN FROM THE MORTAR BOX, A STAMP STOP. A (HUMAN'S) SHOE, A DIE FROM THE BOTTOM OF A MORTAR BOX, AN AMALGAM SCRAPPER AND AN AMALGAM BUCKET. - Standard Gold Mill, East of Bodie Creek, Northeast of Bodie, Bodie, Mono County, CA

  6. Influence of dental materials on dental MRI

    PubMed Central

    Tymofiyeva, O; Vaegler, S; Rottner, K; Boldt, J; Hopfgartner, AJ; Proff, PC; Richter, E-J; Jakob, PM

    2013-01-01

    Objectives: To investigate the potential influence of standard dental materials on dental MRI (dMRI) by estimating the magnetic susceptibility with the help of the MRI-based geometric distortion method and to classify the materials from the standpoint of dMRI. Methods: A series of standard dental materials was studied on a 1.5 T MRI system using spin echo and gradient echo pulse sequences and their magnetic susceptibility was estimated using the geometric method. Measurements on samples of dental materials were supported by in vivo examples obtained in dedicated dMRI procedures. Results: The tested materials showed a range of distortion degrees. The following materials were classified as fully compatible materials that can be present even in the tooth of interest: the resin-based sealer AH Plus® (Dentsply, Maillefer, Germany), glass ionomer cement, gutta-percha, zirconium dioxide and composites from one of the tested manufacturers. Interestingly, composites provided by the other manufacturer caused relatively strong distortions and were therefore classified as compatible I, along with amalgam, gold alloy, gold–ceramic crowns, titanium alloy and NiTi orthodontic wires. Materials, the magnetic susceptibility of which differed from that of water by more than 200 ppm, were classified as non-compatible materials that should not be present in the patient’s mouth for any dMRI applications. They included stainless steel orthodontic appliances and CoCr. Conclusions: A classification of the materials that complies with the standard grouping of materials according to their magnetic susceptibility was proposed and adopted for the purposes of dMRI. The proposed classification can serve as a guideline in future dMRI research. PMID:23610088

  7. Review of Spaceflight Dental Emergencies

    NASA Technical Reports Server (NTRS)

    Menon, Anil

    2012-01-01

    All exploration class missions--extending beyond earth's orbit--differ from existing orbital missions by being of longer duration and often not having a means of evacuation. If an exploration mission extends beyond a year, then there will be a greater lapse since the crewmembers last terrestrial dental exams, which routinely occur each year. This increased time since professional dental care could increase the chance of a dental emergency such as intractable pain, dental decay requiring a temporary filling, crown replacement, exposed pulp, abscess, tooth avulsion, or toothache. Additionally, any dental emergency will have to be treated in-flight with available resources and personnel who may not have extensive training in dental care. Thus, dental emergencies are an important risk to assess in preparation for exploration missions.

  8. Reactions of connective tissue to amalgam, intermediate restorative material, mineral trioxide aggregate, and mineral trioxide aggregate mixed with chlorhexidine.

    PubMed

    Sumer, Mahmut; Muglali, Mehtap; Bodrumlu, Emre; Guvenc, Tolga

    2006-11-01

    The aim of this study was to histopathologically examine the biocompatibility of the high-copper amalgam, intermediate restorative material (IRM), mineral trioxide aggregate (MTA), and MTA mixed with chlorhexidine (CHX). This study was conducted to observe the rat subcutaneous connective tissue reaction to the implanted tubes filled with amalgam, IRM, MTA, and MTA mixed with CHX. The animals were sacrificed 15, 30, and 60 days after the implantation procedure. The implant sites were excised and prepared for histological evaluation. Sections of 5 to 6 microm thickness were cut by a microtome and stained with hemotoxylin eosin and examined under a light microscope. The inflammatory reactions were categorized as weak (none or few inflammatory cells < or =25 cells), moderate (>25 cells), and severe (a lot of inflammatory cells not to be counted, giant cells, and granulation tissue). Thickness of fibrous capsules measured five different areas by the digital imaging and the mean values were scored. Amalgam, IRM, and MTA mixed with CHX caused a weak inflammatory response on days 15, 30, and 60. MTA provoked an initial severe inflammatory response that subsided at the 30 and 60 day study period. A clear fibrous capsule was observed beginning from the 15 days in all of the groups. Within the limits of this study, amalgam, IRM, MTA, and MTA mixed with CHX materials were surrounded by fibrous connective tissue indicated that they were well tolerated by the tissues, therefore, MTA/CHX seemed to be biocompatible.

  9. Dental cavities

    MedlinePlus

    ... it with a material such as silver alloy, gold, porcelain, or composite resin. Porcelain and composite resin ... teeth. Many dentists consider silver amalgam (alloy) and gold to be stronger, and these materials are often ...

  10. Usefulness of an energy-binned photon-counting x-ray detector for dental panoramic radiographs

    NASA Astrophysics Data System (ADS)

    Fukui, Tatsumasa; Katsumata, Akitoshi; Ogawa, Koichi; Fujiwara, Shuu

    2015-03-01

    A newly developed dental panoramic radiography system is equipped with a photon-counting semiconductor detector. This photon-counting detector acquires transparent X-ray beams by dividing them into several energy bands. We developed a method to identify dental materials in the patient's teeth by means of the X-ray energy analysis of panoramic radiographs. We tested various dental materials including gold alloy, dental amalgam, dental cement, and titanium. The results of this study suggest that X-ray energy scattergram analysis could be used to identify a range of dental materials in a patient's panoramic radiograph.

  11. Dental hyponatraemia.

    PubMed

    Simpson, R M

    2011-08-01

    A 14-year-old girl developed dental pain and was treated for acute infected pulpitis of her right upper lateral incisor with drilling and filling. The pain continued and was helped by analgesia, sucking ice cubes and drinking cold water. Forty-eight hours later, she became confused and disoriented. She started to vomit and complained of headache. Investigations revealed hyponatraemia with normal serum potassium levels and initially normal urinary sodium excretion. Over the next 24 hours, she passed 5.45 L of urine and her serum sodium rose from 125 to 143 mmol/L. Self-induced water intoxication has been described during drinking games and initiation ceremonies, but this would appear to an unusual cause. Conservative management proved successful in allowing this girl to recover without sequelae. PMID:21873727

  12. In vivo assessment of secondary caries and dentin characteristics after traditional amalgam restorations

    PubMed Central

    de Assunção Pinheiro, Isauremi Vieira; Borges, Boniek Castillo Dutra; de Lima, Kenio Costa

    2012-01-01

    Objective This study aimed to evaluate in vivo the occurrence of secondary caries and dentin characteristics in permanent molars after traditional amalgam restorations, by means of clinical visual examination, radiographs and laser-induced fluorescence (LF) (DIAGNOdent). Methods: Thirty first permanent molars of 30 schoolchildren in the 7 to14 year-old age group were included. Caries was removed by hand. Thus, indirect pulp capping was performed with glass-ionomer cement (GIC), the cavity was varnished and amalgam filled. LF was measured before and after cavity preparation and after a 12-month observation period. Dentin color after cavity preparation and after the 12-month observation period was recorded. Recurrent caries was also investigated by visual clinical and radiographic examinations, in addition to dentin thickness between pulp and indirect GIC pulp capping. Data was analyzed by ANOVA for repeated measurements, paired “t” test and descriptive statistic. Results: There were statistically significant differences (P<.05) among LF scores for dentin in all periods evaluated, with the lowest scores shown after 12 month of observation. There was no statistical difference between dentin color after cavity preparation and following 12 months of observation. Moreover, there was no recurrent caries attack at 12-month follow-up; dentin thickness between pulp and indirect GIC pulp capping was similar between baseline and final observation periods. It was concluded that the clinical restorative procedure using hand caries removal, indirect pulp capping with GIC, varnishing and amalgam filling the cavity did not provide secondary caries and increased dentin mineral content after 12 months. PMID:22904654

  13. Dental Sealants

    MedlinePlus

    ... Data & Statistics > Find Data by Topic > Dental Sealants Dental Sealants Main Content Dental sealants are thin plastic coatings that protect the chewing surfaces of children’s back teeth from tooth decay. Overall, the prevalence of sealants ...

  14. 21 CFR 872.3820 - Root canal filling resin.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Root canal filling resin. 872.3820 Section 872...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3820 Root canal filling resin. (a) Identification. A root canal filling resin is a device composed of material, such as methylmethacrylate,...

  15. 21 CFR 872.3820 - Root canal filling resin.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Root canal filling resin. 872.3820 Section 872...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3820 Root canal filling resin. (a) Identification. A root canal filling resin is a device composed of material, such as methylmethacrylate,...

  16. 21 CFR 872.3820 - Root canal filling resin.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Root canal filling resin. 872.3820 Section 872...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3820 Root canal filling resin. (a) Identification. A root canal filling resin is a device composed of material, such as methylmethacrylate,...

  17. 21 CFR 872.3820 - Root canal filling resin.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Root canal filling resin. 872.3820 Section 872...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3820 Root canal filling resin. (a) Identification. A root canal filling resin is a device composed of material, such as methylmethacrylate,...

  18. 21 CFR 872.3310 - Coating material for resin fillings.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3310 Coating material for resin fillings. (a) Identification. A coating material for resin fillings is a device intended to be applied to the... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Coating material for resin fillings....

  19. 21 CFR 872.3310 - Coating material for resin fillings.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3310 Coating material for resin fillings. (a) Identification. A coating material for resin fillings is a device intended to be applied to the... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Coating material for resin fillings....

  20. 21 CFR 872.3310 - Coating material for resin fillings.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3310 Coating material for resin fillings. (a) Identification. A coating material for resin fillings is a device intended to be applied to the... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Coating material for resin fillings....

  1. 21 CFR 872.3310 - Coating material for resin fillings.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Coating material for resin fillings. 872.3310... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3310 Coating material for resin fillings. (a) Identification. A coating material for resin fillings is a device intended to be applied to...

  2. Dental Procedures.

    PubMed

    Ramponi, Denise R

    2016-01-01

    Dental problems are a common complaint in emergency departments in the United States. There are a wide variety of dental issues addressed in emergency department visits such as dental caries, loose teeth, dental trauma, gingival infections, and dry socket syndrome. Review of the most common dental blocks and dental procedures will allow the practitioner the opportunity to make the patient more comfortable and reduce the amount of analgesia the patient will need upon discharge. Familiarity with the dental equipment, tooth, and mouth anatomy will help prepare the practitioner for to perform these dental procedures. PMID:27482994

  3. Determination of ablation threshold for composite resins and amalgam irradiated with femtosecond laser pulses

    NASA Astrophysics Data System (ADS)

    Freitas, A. Z.; Freschi, L. R.; Samad, R. E.; Zezell, D. M.; Gouw-Soares, S. C.; Vieira, N. D., Jr.

    2010-03-01

    The use of laser for caries removal and cavity preparation is already a reality in the dental clinic. The objective of the present study was to consider the viability of ultrashort laser pulses for restorative material selective removal, by determining the ablation threshold fluence for composite resins and amalgam irradiated with femtosecond laser pulses. Lasers pulses centered at 830 nm with 50 fs of duration and 1 kHz of repetition rate, with energies in the range of 300 to 770 μJ were used to irradiate the samples. The samples were irradiated using two different geometrical methods for ablation threshold fluence determinations and the volume ablation was measured by optical coherence tomography. The shape of the ablated surfaces were analyzed by optical microscopy and scanning electron microscopy. The determined ablation threshold fluence is 0.35 J/cm2 for the composite resins Z-100 and Z-350, and 0.25 J/cm2 for the amalgam. These values are half of the value for enamel in this temporal regime. Thermal damages were not observed in the samples. Using the OCT technique (optical coherence tomography) was possible to determine the ablated volume and the total mass removed.

  4. Biomechanical Stress Analysis of Mandibular First Permanent Molar; Restored with Amalgam and Composite Resin: A Computerized Finite Element Study

    PubMed Central

    Prabhakar, AR

    2010-01-01

    Normal mastication with its varying magnitude and direction generates considerable reactionary stresses in teeth and their supporting tissues. The structure of the human tooth and its supporting tissues is a complex assemblage of materials of varied mechanical properties. The finite element method (FEM), a modern technique of numerical stress analysis, has the great advantage of being applicable to solids of irregular geometry and heterogeneous material properties and therefore ideally suited to the examination of structural behavior of teeth. The mandibular first permanent molar is one of the earliest permanent teeth to erupt in the oral cavity and hence most prone to caries. The purpose of the present study was to construct a two-dimensional FE model of the mandibular first permanent molar and its supporting structures, using a FE software called NISA II-Display III, EMRC, USA to study the following: • To compare stress distributions patterns when a modeled Class I Cavity was restored with dental amalgam and composite resin. • To compare the stress distributions pattern when the load was applied to different to locations, i.e.: At the mesial cusp tip, and at the center of the occlusal surface. Both amalgam and composite resin showed similar stress distribution pattern, however, the magnitudes of stresses generated in the tooth restored with composite resin were higher. Thus, amalgam is a better restorative material in distributing stresses.

  5. New inorganic/organic copolymers (ORMOCER{reg_sign}s) for dental applications

    SciTech Connect

    Wolter, H.; Storch, W.; Ott, H.

    1994-12-31

    Urethane and thioether (meth)acrylate alkoxysilanes have been used, as sol-gel precursors, for the preparation of a special family of inorganic/organic copolymers (ORMOCER{reg_sign}s). The basic silane type offers the following structural and synthetic possibilities for modifying the properties of the resulting copolymers: variation of the number of alkoxy groups, combination with other, different, sol-gel precursors, variation of the number of attached (meth)acrylate groups (1--5), and variation within the molecular segment (kind, structure and length) connecting the inorganic with the organic polymer structure. To achieve the additional organic polymer structure in the cured copolymer the use of different radically induced polymerization approaches (UV-, visible light-, thermal- and redox induced) is possible. Taking the incorporation of fillers into account, the Young`s modulus of these copolymers is adjustable in a range of 1--17,000 MPa, and the thermal expansion coefficient in a range of 17--250{center_dot}10{sup {minus}6}{center_dot}K{sup {minus}1} (5--50 C). Other advantages are the low shrinkage (1--2,8 vol.-%), the high flexural strength (up to 160 MPa), and the high abrasion resistance. This new copolymer type seems to have significant potential for medical applications, especially as dental filling material to replace the currently used controversial amalgam fillings.

  6. Effect of bonded amalgam on the fracture resistance of teeth.

    PubMed

    Eakle, W S; Staninec, M; Lacy, A M

    1992-08-01

    The purpose of this study was to determine whether amalgam bonded to tooth structure with an adhesive resin cement can increase the fracture resistance of restored teeth. Extracted paired upper premolars were prepared for G.V. Black type mesioocclusodistal amalgam restorations. In one tooth of each pair (the experimental group), the enamel walls were etched with phosphoric acid and were painted with an adhesive resin (Panavia), and amalgam was condensed and carved. For the other tooth in each pair (the control group), amalgam was placed in the same manner but was not etched and lined with resin. The teeth were thermocycled and mounted for testing and then were loaded until fracture. A significant difference (p less than 0.05, the paired Student's t-test) was found in the force needed to fracture the bonded amalgam group (70.5 +/- 21.6 kg) compared with that needed to fracture the conventional amalgam group (60.3 +/- 16.8 kg). SEM examination of fractures at the interface occurred predominantly within the resin. PMID:1501170

  7. Health maintenance facility: Dental equipment requirements

    NASA Technical Reports Server (NTRS)

    Young, John; Gosbee, John; Billica, Roger

    1991-01-01

    The objectives were to test the effectiveness of the Health Maintenance Facility (HMF) dental suction/particle containment system, which controls fluids and debris generated during simulated dental treatment, in microgravity; to test the effectiveness of fiber optic intraoral lighting systems in microgravity, while simulating dental treatment; and to evaluate the operation and function of off-the-shelf dental handheld instruments, namely a portable dental hand drill and temporary filling material, in microgravity. A description of test procedures, including test set-up, flight equipment, and the data acquisition system, is given.

  8. Scanning probe microscopy on new dental alloys

    NASA Astrophysics Data System (ADS)

    Reusch, B.; Geis-Gerstorfer, J.; Ziegler, C.

    Surface analytical methods such as scanning force microscopy (SFM), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were used to determine the surface properties of amalgam substitutes as tooth filling materials. In particular the corrosion and the passivation behavior of new gallium restorative materials were studied. To give relevant practical data, the measurements were performed with and without the alloys being stored in artificial saliva to simulate physiological oral conditions.

  9. Filling agents.

    PubMed

    Glavas, Ioannis P

    2005-06-01

    Injectable fillers have become an important component of minimally invasive facial rejuvenation modalities. Their ease of use, effectiveness, low morbidity, and fast results with minimal downtime are factors that have made them popular among patients. Soft tissue augmentation has evolved to a unique combination of medicine and art. A wide selection of available agents and new products, each one with unique properties, may be used alone or in combination. The physician acquires the tools to rebalance facial characteristics not only by filling wrinkles but also by having the ability to shape the face and restore bony contours and lines. Careful selection of candidates, realistic expectations, and an understanding of the limitations of fillers are crucial for a successful result.

  10. Design and evaluation of a filter-based chairside amalgam separation system.

    PubMed

    Stone, Mark E; Cohen, Mark E; Berry, Denise L; Ragain, James C

    2008-06-15

    This study evaluated the ability of a chairside filtration system to remove particulate-based mercury (Hg) from dental-unit wastewater. Prototypes of the chairside filtration system were designed and fabricated using reusable filter chambers with disposable filter elements. The system was installed in five dental operatories utilizing filter elements with nominal pore sizes of 50 microm, 15 microm, 1 microm, 0.5 microm, or with no system installed (control). Daily chairside wastewater samples were collected on ten consecutive days from each room and brought to the laboratory for processing. After processing the wastewater samples, Hg concentrations were determined with cold vapor atomic absorption spectrometry (USEPA method 7470A). Filter systems were exchanged after ten samples were collected so that all five of the configurations were evaluated in each room (with assignment order balanced by a Latin Square). The numbers of surfaces of amalgam placed and removed per day were tracked in each room. In part two, new filter systems with the 0.5 microm filter elements were installed in the five dental operatories and vacuum levels at the high-velocity evacuation cannula tip were measured with a vacuum gauge. In part three of the study, the chairside filtration system utilizing 0.5 microm and 15 microm filter elements was evaluated utilizing the ISO 11143 testing protocol, a laboratory test of amalgam separator efficiency utilizing amalgam samples of known particle size distribution. Mean Hg per chair per day (no filter installed) was 1087.38 mg (SD = 993.92 mg). Mean Hg per chair per day for the 50 microm, 15 microm, 1 microm, 0.5 microm filter configurations was 79.13 mg (SD = 71.40 mg), 23.55 mg (SD = 23.25 mg), 17.68 mg (SD = 17.35 mg), and 4.25 mg (SD = 6.35 mg), respectively (n = 50 for all groups). Calculated removal efficiencies from the clinical samples were 92.7%, 97.8%, 98.4%, and 99.6%, respectively. ANCOVA on data from the four filter groups, with amalgam

  11. Microleakage in amalgam restorations: influence of cavity cleanser solutions and anticariogenic agents.

    PubMed

    Piva, E; Martos, J; Demarco, F F

    2001-01-01

    This study evaluated in vitro the influence of five solutions used to treat cavity preparations on microleakage of amalgam restorations. Seventy-two standard Class V cavities were prepared in buccal and lingual surfaces of 36 recently extracted human third molars. The cervical wall was located in cementum and the occlusal wall was located in enamel. Specimens were randomly divided into six groups (n=12) according to the solution employed to treat the cavities: Group I-2.5% sodium hypochlorite; Group II-Calcium hydroxide solution; Group III-1.23% Acidulated phosphate fluoride; Group IV-2% digluconate of chlorhexidine; Group V-anionic detergent solution (1.25% sodium lauryl sulfate) and Group VI-control group. The solutions were applied for one minute, followed by washing and drying. Two coats of copal varnish were applied in each cavity. The cavities were filled with capsuled amalgam GS-80 (SDI). After finishing and polishing, the specimens were submitted for thermal cycling followed by immersion in methylene blue. Then, the specimens were sectioned and microleakage was evaluated based on a standard ranking under magnification (40x). Data were subjected to statistical analysis using non-parametric tests. Results of the study concluded that leakage was higher in cementum than enamel (p<0.01). The substances employed have no influence on microleakage except for sodium hypochlorite, which increased leakage values in enamel (p<0.05).

  12. Comparative study of mechanical properties of dental restorative materials and dental hard tissues in compressive loads

    PubMed Central

    Lee, Jong Yeop

    2014-01-01

    There are two objectives. One is to show the differences in the mechanical properties of various dental restorative materials compared to those of enamel and dentin. The other is to ascertain which dental restorative materials are more suitable for clinical treatments. Amalgam, dental ceramic, gold alloy, dental resin, zirconia, and titanium alloy were processed as dental restorative material specimens. The specimens (width, height, and length of 1.2, 1.2, and 3.0 mm, respectively) were compressed at a constant loading speed of 0.1 mm/min. The maximum stress (115.0 ± 40.6, 55.0 ± 24.8, 291.2 ± 45.3, 274.6 ± 52.2, 2206.0 ± 522.9, and 953.4 ± 132.1 MPa), maximum strain (7.8% ± 0.5%, 4.0% ± 0.1%, 12.7% ± 0.8%, 32.8% ± 0.5%, 63.5% ± 14.0%, and 45.3% ± 7.4%), and elastic modulus (1437.5 ± 507.2, 1548.4 ± 583.5, 2323.4 ± 322.4, 833.1 ± 92.4, 3895.2 ± 202.9, and 2222.7 ± 277.6 MPa) were evident for amalgam, dental ceramic, gold alloy, dental resin, zirconia, and titanium alloy, respectively. The reference hardness value of amalgam, dental ceramic, gold alloy, dental resin, zirconia, and titanium alloy was 90, 420, 130–135, 86.6–124.2, 1250, and 349, respectively. Since enamel grinds food, its abrasion resistance is important. Therefore, hardness value should be prioritized for enamel. Since dentin absorbs bite forces, mechanical properties should be prioritized for dentin. The results suggest that gold alloy simultaneously has a hardness value lower than enamel (74.8 ± 18.1), which is important in the wear of the opposing natural teeth, and higher maximum stress, maximum strain, and elastic modulus than dentin (193.7 ± 30.6 MPa, 11.9% ± 0.1%, 1653.7 ± 277.9 MPa, respectively), which are important considering the rigidity to absorb bite forces. PMID:25352921

  13. Blood lead level and dental caries in school-age children.

    PubMed Central

    Gemmel, Allison; Tavares, Mary; Alperin, Susan; Soncini, Jennifer; Daniel, David; Dunn, Julie; Crawford, Sybil; Braveman, Norman; Clarkson, Thomas W; McKinlay, Sonja; Bellinger, David C

    2002-01-01

    The association between blood lead level and dental caries was evaluated in cross-sectional analyses of baseline data for 543 children 6-10 years old screened for enrollment in the Children's Amalgam Trial, a study designed to assess potential health effects of mercury in silver fillings. Approximately half of the children were recruited from an urban setting (Boston/Cambridge, MA, USA) and approximately half from a rural setting (Farmington, ME, USA). Mean blood lead level was significantly greater among the urban subgroup, as was the mean number of carious tooth surfaces. Blood lead level was positively associated with number of caries among urban children, even with adjustment for demographic and maternal factors and child dental practices. This association was stronger in primary than in permanent dentition and stronger for occlusal, lingual, and buccal tooth surfaces than for mesial or distal surfaces. In general, blood lead was not associated with caries in the rural subgroup. The difference between the strength of the associations in the urban and rural settings might reflect the presence of residual confounding in the former setting, the presence of greater variability in the latter setting in terms of important caries risk factors (e.g., fluoride exposure), or greater exposure misclassification in the rural setting. These findings add to the evidence supporting a weak association between children's lead exposure and caries prevalence. A biologic mechanism for lead cariogenicity has not been identified, however. Our data are also consistent with residual confounding by factors associated with both elevated lead exposure and dental caries. PMID:12361944

  14. Dental Hygienists

    MedlinePlus

    ... anatomy, patient management, and periodontics, which is the study of gum disease. High school students interested in becoming dental hygienists should take courses in biology, chemistry, and math. Most dental hygiene programs also require applicants to have completed at ...

  15. Dental sealants

    MedlinePlus

    ... this page: //medlineplus.gov/ency/patientinstructions/000779.htm Dental sealants To use the sharing features on this ... case a sealant needs to be replaced. How Dental Sealants Are Applied Your dentist applies sealants on ...

  16. Mercury Vapor Sorption and Amalgamation with a Thin Gold Film.

    PubMed

    Hou, Tingting; Chen, Miao; Greene, George W; Horn, Roger G

    2015-10-21

    Understanding the amalgamation mechanisms between mercury and gold is of fundamental interest and importance to many mercury sensing applications. However, there is only limited and piecemeal discussion in the literature of the mechanisms by which Au-Hg amalgams are formed on thin Au films. Here, we present a comprehensive description of a series of morphological changes occurring in a thin polycrystalline Au film during Au-Hg amalgamation investigated by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and atomic force microscopy (AFM). These microscopic investigations enable us to offer a coherent explanation for the features and the mechanisms of amalgamation of Hg with Au in the film. We also use an optical technique (fringes of equal chromatic order, FECO) to observe changes in optical thickness and reflectivity of the film. Amalgamation reactions in the film render it inhomogeneous, thus making optical techniques unsuitable as a method for quantitative monitoring of Hg vapor using Au films of this type.

  17. Silver-tin alloys and amalgams: electrochemical considerations.

    PubMed

    Mueller, H J

    1980-01-01

    The corrosion potential and anodic polarization profiles of a representative number of silver-tin alloys and their corresponding amalgams in a physiological solution were determined and compared to their microstructures. For the alloys with tin-content greater than 27%(wt) and for all amalgams, the corrosion process is related to the attack of free tin for the alloys and to the gamma-2 tin for the amalgams. The gamma-2 concentration in the amalgams increases with an increase in tin-content. For alloys with tin-content less than 27%, the corrosion process is even more restricted than for the process observed with pure silver. From a developed theory based upon the potential-time and polarization results, association of the O2 reduction process on a SnO cathodic film to an intermediate specie of H2O2 is made. The rate of H2O2 decomposition on a SnO surface in a four electron process is thought to control the O2 reduction overvoltage. The O2 reduction overvoltage decreases with increases in the silver-content of the amalgam, particularily seen with the 8 and 12% tin compositions. Due to the polarization induced corrosion process, a phase with high silver and high mercury concentrations was observed over the unreacted particles.

  18. Mercury Vapor Sorption and Amalgamation with a Thin Gold Film.

    PubMed

    Hou, Tingting; Chen, Miao; Greene, George W; Horn, Roger G

    2015-10-21

    Understanding the amalgamation mechanisms between mercury and gold is of fundamental interest and importance to many mercury sensing applications. However, there is only limited and piecemeal discussion in the literature of the mechanisms by which Au-Hg amalgams are formed on thin Au films. Here, we present a comprehensive description of a series of morphological changes occurring in a thin polycrystalline Au film during Au-Hg amalgamation investigated by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and atomic force microscopy (AFM). These microscopic investigations enable us to offer a coherent explanation for the features and the mechanisms of amalgamation of Hg with Au in the film. We also use an optical technique (fringes of equal chromatic order, FECO) to observe changes in optical thickness and reflectivity of the film. Amalgamation reactions in the film render it inhomogeneous, thus making optical techniques unsuitable as a method for quantitative monitoring of Hg vapor using Au films of this type. PMID:26486235

  19. [Despite all--do we have an appropriate substitute for amalgam?].

    PubMed

    Levin, L; Samorodnitzky-Naveh, G; Coval, M; Geiger, S B

    2008-04-01

    The ultimate success or failure of a restored tooth is largely dependent on clinical management. Clinicians may choose from a number of restorative materials, different clinical techniques and cavity preparation procedures. Composite resin has been used for nearly 50 years as a restorative material in dentistry. The use of this material has recently increased as a result of patients' demands for esthetic restorations. Failure of dental restorations is a major concern in dental practice. Replacement of failed restorations constitutes the majority of operative work. Clinicians should be aware of the longevity of, and likely reasons for the failure of, direct posterior restorations. Higher failure rates were observed in resin-based composite restorations as compares amalgam restorations. Secondary caries was the main reason for failure. Posterior interproximal resin-based composite restorations should be considered with caution, and their limited long-term performance should be kept in mind. Patients should be informed about the potential longevity of restorative treatment for posterior teeth as they make decisions about treatment for their oral restorative needs.

  20. Surface characterization of amalgam made with Hg-In liquid alloy.

    PubMed

    Nakajima, H; Akaiwa, Y; Hashimoto, H; Ferracane, J L; Okabe, T

    1997-01-01

    When amalgam was triturated with Hg-In liquid alloys instead of pure mercury, the resultant amalgams released a significantly smaller amount of mercury vapor during setting. To understand the mechanisms responsible for the drastic decrease in mercury evaporation from the In-containing amalgam, we used Auger Electron Spectroscopy to examine surface oxide films on amalgams made with Hg-10 wt% In or pure mercury. The surface of the In-containing amalgam was rapidly covered with both indium and tin oxide films. Greater amounts of oxygen were found on the gamma 1 Ag-Hg matrix in the In-containing amalgam than in the amalgam without indium. The rapid formation of the oxide film contributes to a reduction in the mercury release from the In-containing amalgam by forming an effective barrier to evaporation. PMID:9042085

  1. Integrated starting and running amalgam assembly for an electrodeless fluorescent lamp

    DOEpatents

    Borowiec, Joseph Christopher; Cocoma, John Paul; Roberts, Victor David

    1998-01-01

    An integrated starting and running amalgam assembly for an electrodeless SEF fluorescent lamp includes a wire mesh amalgam support constructed to jointly optimize positions of a starting amalgam and a running amalgam in the lamp, thereby optimizing mercury vapor pressure in the lamp during both starting and steady-state operation in order to rapidly achieve and maintain high light output. The wire mesh amalgam support is constructed to support the starting amalgam toward one end thereof and the running amalgam toward the other end thereof, and the wire mesh is rolled for friction-fitting within the exhaust tube of the lamp. The positions of the starting and running amalgams on the wire mesh are jointly optimized such that high light output is achieved quickly and maintained, while avoiding any significant reduction in light output between starting and running operation.

  2. Novel Amalgams for In-Space Fabrication of Replacement Parts

    NASA Technical Reports Server (NTRS)

    Cochran, Calvin T.; Van Hoose, James R.; Grugel, R. N.

    2012-01-01

    Being able to fabricate replacement parts during extended space flight missions precludes the weight, storage volume, and speculation necessary to accommodate spares. Amalgams, widely used in dentistry, are potential candidates for fabricating parts in microgravity environments as they are moldable, do not require energy for melting, and do not pose fluid handling problems. Unfortunately, amalgams have poor tensile strength and the room temperature liquid component is mercury. To possibly resolve these issues a gallium-indium alloy was substituted for mercury and small steel fibers were mixed in with the commercial alloy powder. Subsequent microscopic examination of the novel amalgam revealed complete bonding of the components, and mechanical testing of comparable samples showed those containing steel fibers to have a significant improvement in strength. Experimental procedures, microstructures, and test results are presented and discussed in view of further improving properties.

  3. FRIENDSHIP CHOICES OF MULTIRACIAL ADOLESCENTS: RACIAL HOMOPHILY, BLENDING, OR AMALGAMATION?*

    PubMed Central

    Doyle, Jamie Mihoko; Kao, Grace

    2009-01-01

    Using the National Longitudinal Study of Adolescent Health (Add Health), we utilize the concepts of homophily, blending, and amalgamation to describe the possible friendship patterns of multiracials. Homophily occurs when multiracials are most likely to choose other multiracials as friends. Blending occurs when friendship patterns of multiracials are somewhere in-between those of their monoracial counterparts. Amalgamation consists of friendship patterns that are similar to one of their monoracial counterparts. All groups exhibit signs of amalgamation such that non-white multiracials resemble Blacks, and White multiracials resemble whites except for Black-White multiracials. Black-Whites, Asian-Whites, and Asian-Blacks also exhibit signs of blending, while only Native American multiracials show signs of homophily. Multiracials have different experiences depending on their specific racial composition, and while they seem to bridge the distance between racial groups, their friendship patterns also fall along Black and White lines. PMID:19727415

  4. Dental Composite Restorations and Psychosocial Function in Children

    PubMed Central

    Trachtenberg, Felicia L.; Hauser, Russ; McKinlay, Sonja; Shrader, Peter; Tavares, Mary; Bellinger, David C.

    2012-01-01

    BACKGROUND AND OBJECTIVE: Resin-based dental materials may intraorally release their chemical components and bisphenol A. The New England Children’s Amalgam Trial found that children randomized to amalgam had better psychosocial outcomes than those assigned to composites for posterior tooth restorations. The objective of this study was to examine whether greater exposure to dental composites is associated with psychosocial problems in children. METHODS: Analysis of treatment-level data from the New England Children’s Amalgam Trial, a 2-group randomized safety trial comparing amalgam with the treatment plan of bisphenol A-glycidyl methacrylate (bisGMA)-based composite and urethane dimethacrylate–based polyacid-modified composite (compomer), among 534 children aged 6 to 10 years at baseline. Psychosocial function at follow-up (n = 434) was measured by using the self-reported Behavior Assessment System for Children (BASC-SR) and parent-reported Child Behavior Checklist (CBCL). RESULTS: Children with higher cumulative exposure to bisGMA-based composite had poorer follow-up scores on 3 of 4 BASC-SR global scales: Emotional Symptoms (β = 0.8, SE = 0.3, P = .003), Clinical Maladjustment (β = 0.7, SE = 0.3, P = .02), and Personal Adjustment (β = –0.8, SE = 0.2, P = .002). Associations were stronger with posterior-occlusal (chewing) surfaces, where degradation of composite was more likely. For CBCL change, associations were not statistically significant. At-risk or clinically significant scores were more common among children with greater exposure for CBCL Total Problem Behaviors (16.3% vs 11.2%, P-trend = .01) and numerous BASC-SR syndromes (eg, ≥13 vs 0 surface-years, Interpersonal Relations 13.7% vs 4.8%, P-trend = .01). No associations were found with compomer, nor with amalgam exposure levels among children randomized to amalgam. CONCLUSIONS: Greater exposure to bisGMA-based dental composite restorations was associated with impaired psychosocial function

  5. Dental OCT

    NASA Astrophysics Data System (ADS)

    Colston, Bill W.; Sathyam, Ujwal S.; Dasilva, Luiz B.; Everett, Matthew J.; Stroeve, Pieter; Otis, L. L.

    1998-09-01

    We present here the first in vivo optical coherence tomography (OCT) images of human dental tissue. A novel dental optical coherence tomography system has been developed. This system incorporates the interferometer sample arm and transverse scanning optics into a handpiece that can be used intraorally to image human dental tissues. The average imaging depth of this system varied from 3 mm in hard tissues to 1.5 mm in soft tissues. We discuss the application of this imaging system for dentistry and illustrate the potential of our dental OCT system for diagnosis of periodontal disease, detection of caries, and evaluation of dental restorations.

  6. Silver glass ionomer cement as a retrograde filling material: a study in vitro.

    PubMed

    Pissiotis, E; Sapounas, G; Spångberg, L S

    1991-05-01

    Comparison was made of the apical microleakage of retrograde fillings with amalgam and with silver glass ionomer cements using a modified dye penetration method. Forty instrumented human teeth were divided into four groups. Each group was characterized by a different retrograde filling material or technique: Group 1--silver glass ionomer (SGI); group 2--SGI with previous acid wash of the cavity; group 3--SGI in a previously acid washed cavity, protected with varnish; and group 4--zinc-free amalgam. A paper cone for dye adsorption analysis was placed in contact with retrofill and the main canal was obturated with thermoplasticized gutta-percha. All teeth were coated, immersed in methylene blue dye, and evacuated to assure complete penetration of the dye in any possible void. Later the teeth were cleared and evaluated under stereomicroscope. Statistical analysis showed that group 1 had the least microleakage of all. In addition, the biocompatibility of the SGI and varnish was compared with that of amalgam using the 51Cr release evaluation method. The results showed that SGI and varnish were less cytotoxic than amalgam. It was concluded that SGI cement can be considered an alternative retrograde filling material.

  7. Exposures of dental professionals to elemental mercury and methylmercury.

    PubMed

    Goodrich, Jaclyn M; Chou, Hwai-Nan; Gruninger, Stephen E; Franzblau, Alfred; Basu, Niladri

    2016-01-01

    Mercury (Hg) exposure, a worldwide public health concern, predominantly takes two forms--methylmercury from fish consumption and elemental Hg from dental amalgam restorations. We recruited 630 dental professionals from an American Dental Association meeting to assess Hg body burden and primary sources of exposure in a dually exposed population. Participants described occupational practices and fish consumption patterns via questionnaire. Hg levels in biomarkers of elemental Hg (urine) and methylmercury (hair and blood) were measured with a Direct Mercury Analyzer-80 and were higher than the general US population. Geometric means (95% CI) were 1.28 (1.19-1.37) μg/l in urine, 0.60 (0.54-0.67) μg/g in hair and 3.67 (3.38-3.98) μg/l in blood. In multivariable linear regression, personal amalgams predicted urine Hg levels along with total years in dentistry, amalgams handled, working hours and sex. Fish consumption patterns predicted hair and blood Hg levels, which were higher among Asians compared with Caucasians. Five species contributed the majority of the estimated Hg intake from fish--swordfish, fresh tuna, white canned tuna, whitefish and king mackerel. When studying populations with occupational exposure to Hg, it is important to assess environmental exposures to both elemental Hg and methylmercury as these constitute a large proportion of total exposure. PMID:26329138

  8. Tooth-Colored Fillings

    MedlinePlus

    ... Dental Implants Dentures Direct Bonding Implants versus Bridges Orthodontics and Aligners Periodontal Plastic Surgery Porcelain Crowns Porcelain ... Dental Implants Dentures Direct Bonding Implants versus Bridges Orthodontics and Aligners Periodontal Plastic Surgery Porcelain Crowns Porcelain ...

  9. Dental visits, dental health status and need for dental treatment in a Danish industrial population.

    PubMed

    Petersen, P E

    1983-01-01

    The purpose of the present investigation was to study the utilization of dental services, the distribution of dental diseases and treatment needs in a Danish industrial population. The study covered the male population at a Danish shipyard, and a sample of 988 workers and clerical and managerial staff was drawn by stratified random sampling. 841 persons were interviewed regarding dental visits and attitudes towards dental health services and data on dental health and treatment needs were collected. 61% of the participants aged 15-64 years made regular dental visits at least once a year. The percentages of regular visitors varied according to age and occupation, from 68 to 82% among clerical staff to 34 to 51% among workers. The mean DMF-T increased from 16.6 in the age group 15-24 to 27.0 among the 55-64-year-olds. Untreated dental decay was predominant among workers and persons never seeing a dentist, whereas there were more filled teeth and fewer missing teeth among staff and regular visitors. The periodontal status was less satisfactory in the older age groups and among workers, and most denture wearers were found in the age group 35-64 and among workers. Concordant to the findings on dental health status, dental treatment needs due to caries and periodontal disease as well as prosthetic treatment needs varied according to age, occupation and dental visits. More radical treatment types were needed in the older age groups, among workers and non-regular visitors. The present study seems to indicate that dental diseases in the adult Danish population are not under control.

  10. 21 CFR 872.3275 - Dental cement.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    .... Zinc oxide-eugenol is a device composed of zinc oxide-eugenol intended to serve as a temporary tooth filling or as a base cement to affix a temporary tooth filling, to affix dental devices such as crowns or bridges, or to be applied to a tooth to protect the tooth pulp. (2) Classification. Class I...

  11. 21 CFR 872.3275 - Dental cement.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    .... Zinc oxide-eugenol is a device composed of zinc oxide-eugenol intended to serve as a temporary tooth filling or as a base cement to affix a temporary tooth filling, to affix dental devices such as crowns or bridges, or to be applied to a tooth to protect the tooth pulp. (2) Classification. Class I...

  12. 21 CFR 872.3275 - Dental cement.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    .... Zinc oxide-eugenol is a device composed of zinc oxide-eugenol intended to serve as a temporary tooth filling or as a base cement to affix a temporary tooth filling, to affix dental devices such as crowns or bridges, or to be applied to a tooth to protect the tooth pulp. (2) Classification. Class I...

  13. An estimate for the rank of the intersection of subgroups in free amalgamated products of two groups with normal finite amalgamated subgroup

    SciTech Connect

    Zakharov, Alexander O

    2013-02-28

    We generalize the estimate for the rank of intersection of subgroups in free products of groups, proved earlier by Ivanov and Dicks (which is analogous to the Hanna Neumann inequality in free groups) to the case of free amalgamated products of groups with normal finite amalgamated subgroup. We also prove that the estimate obtained is sharp and cannot be further improved when the amalgamated product contains an involution. Bibliography: 11 titles.

  14. Solidification/Stabilization of Elemental Mercury Waste by Amalgamation

    SciTech Connect

    Yim, S. P.; Ahn, B. G.; Lee, H. J.; Shon, J. S.; Chung, H.; Kim, K. J.; Lee, C. K.

    2003-02-24

    Experiments on solidification of elemental mercury waste were conducted by amalgamation with several metal powders such as copper, zinc, tin, brass and bronze. Unlike the previous studies which showed a dispersible nature after solidification, the waste forms were found to possess quite large compressive strengths in both copper and bronze amalgam forms. The durability was also confirmed by showing very minor changes of strength after 90 days of water immersion. Leachability from the amalgam forms is also shown to be low: measured mercury concentration in the leachate by the Toxicity Characteristic Leaching Procedure (TCLP) was well below the Environmental Protection Agency (EPA) limit. Long term leaching behavior by Accelerated Leach Test (ALT) has shown that the leaching process was dominated by diffusion and the effective diffusion coefficient was quite low (around 10-19 cm2/sec). The mercury vapor concentration from the amalgam forms were reduced to a 20% level of that for elemental mercury and to one-hundredth after 3 months.

  15. Management of large radicular cyst associated with amalgam particles in cystic lining.

    PubMed

    Borkar, Swati A; Dhupar, Vikas; Gadkar, Abhilasha M; Nivedita, C K V S

    2016-01-01

    The failure of amalgam retrofilling and presence of an associated cystic lesion makes surgical endodontic intervention inevitable. Amalgam retrofilling can also give rise to mucoperiosteal tattoo formation and allow incorporation of amalgam particles in the cystic lining. Such a finding has not yet been reported in the endodontic literature. This case report describes the successful endodontic management of a large radicular cyst associated with failed amalgam retrofilling, mucoperiosteal tattoo and amalgam particles dispersed in the epithelial cystic lining. All four mandibular incisors associated with the lesion presented with Weine Type II canal anatomy. The follow-up revealed clinical and radiographic signs of healing. PMID:27217645

  16. Management of large radicular cyst associated with amalgam particles in cystic lining

    PubMed Central

    Borkar, Swati A.; Dhupar, Vikas; Gadkar, Abhilasha M.; Nivedita, C.K.V.S.

    2016-01-01

    The failure of amalgam retrofilling and presence of an associated cystic lesion makes surgical endodontic intervention inevitable. Amalgam retrofilling can also give rise to mucoperiosteal tattoo formation and allow incorporation of amalgam particles in the cystic lining. Such a finding has not yet been reported in the endodontic literature. This case report describes the successful endodontic management of a large radicular cyst associated with failed amalgam retrofilling, mucoperiosteal tattoo and amalgam particles dispersed in the epithelial cystic lining. All four mandibular incisors associated with the lesion presented with Weine Type II canal anatomy. The follow-up revealed clinical and radiographic signs of healing. PMID:27217645

  17. Bonded amalgam sealants and adhesive resin sealants: five-year clinical results.

    PubMed

    Staninec, Michal; Artiga, Nelson; Gansky, Stuart A; Marshall, Grayson W; Eakle, Stephan

    2004-05-01

    Bonded amalgams were used as pit-and-fissure sealants without mechanical preparation. They were compared with resin-based pit-and-fissure sealants for retention over a 5-year period. Clinical examinations at 6 months, 1 year, 2 years, and 5 years revealed no difference between the two techniques. Although amalgam sealants may not be practical by themselves, they can be used to seal pits and fissures surrounding very conservative preparations, in the "preventive amalgam restoration." Conventional amalgam retentive features and 90-degree cavosurface margins may not be necessary when bonding is used with amalgam. PMID:15130073

  18. Dental biometrics: alignment and matching of dental radiographs.

    PubMed

    Chen, Hong; Jain, Anil K

    2005-08-01

    Dental biometrics utilizes dental radiographs for human identification. The dental radiographs provide information about teeth, including tooth contours, elative positions of neighboring teeth, and shapes of the dental work (e.g., crowns, fillings, and bridges). The proposed system has two main stages: feature extraction and matching. The feature extraction stage uses anisotropic diffusion to enhance the images and a Mixture of Gaussians model to segment the dental work. The matching stage has three sequential steps: tooth-level matching, computation of image distances, and subject identification. In the tooth-level matching step, tooth contours are matched using a shape registration method, and the dental work is matched on overlapping areas. The distance between the tooth contours and the distance between the dental work are then combined using posterior probabilities. In the second step, the tooth correspondences between the given query (postmortem) radiograph and the database (antemortem) radiograph are established. A distance based on the corresponding teeth is then used to measure the similarity between the two radiographs. Finally, all the distances between the given postmortem radiographs and the antemortem radiographs that provide candidate identities are combined to establish the identity of the subject associated with the postmortem radiographs.

  19. Metal artifact reduction in dental CT images using polar mathematical morphology.

    PubMed

    Naranjo, Valery; Lloréns, Roberto; Alcañiz, Mariano; López-Mir, Fernando

    2011-04-01

    Most dental implant planning systems use a 3D representation of the CT scan of the patient under study as it provides a more intuitive view of the human jaw. The presence of metallic objects in human jaws, such as amalgam or gold fillings, provokes several artifacts like streaking and beam hardening which makes the reconstruction process difficult. In order to reduce these artifacts, several methods have been proposed using the raw data, directly obtained from the tomographs, in different ways. However, in DICOM-based applications this information is not available, and thus the need of a new method that handles this task in the DICOM domain. The presented method performs a morphological filtering in the polar domain yielding output images less affected by artifacts (even in cases of multiple metallic objects) without causing significant smoothing of the anatomic structures, which allows a great improvement in the 3D reconstruction. The algorithm has been automated and compared to other image denoising methods with successful results. PMID:21227532

  20. Dental Implants

    MedlinePlus

    ... Procedures Dental Implants Dentures Direct Bonding Implants versus Bridges Orthodontics and Aligners Periodontal Plastic Surgery Porcelain Crowns Porcelain Fixed Bridges Porcelain Veneers Repairing Chipped Teeth Teeth Whitening Tooth- ...

  1. The Level of Dental Anxiety and Dental Status in Adult Patients

    PubMed Central

    Dobros, Katarzyna; Hajto-Bryk, Justyna; Wnek, Anna; Zarzecka, Joanna; Rzepka, Dominik

    2014-01-01

    Background: The present study aimed to assess potential correlation between dental anxiety and overall dental status in adult patients, in consideration of the frequency of dental appointments and individual dental hygiene practices. Materials and Methods: Individual dental anxiety levels were assessed with the aid of the Corah’s dental anxiety scale (DAS). The study embraced 112 patients of the University Dental Clinic, Kraków. Following clinical and X-ray exams, respectively, decayed, missing and filled teeth (DMFT) index and dental treatment index (DTI) were computed for each study subject. Results: Mean DAS among the 112 subjects under study was 9.41 standard deviation (SD = 3.36). Mean DMFT value was 15.86 (SD = 7.00), whereas DTI value was 0.76 (SD = 0.27). The number of decayed teeth and an individual dental anxiety level were found to be correlated (r = 0.26). Higher dental anxiety correlated with lower DTI value (r = −0.22) and lesser frequency of dental appointments (r = 0.22). Conclusions: Individual dental anxiety level appears to impact overall dental status, frequency of dental appointments and everyday oral health practices. Every conceivable effort should therefore be undertaken with a view to effectively diminishing dental anxiety levels in the patients. How to cite the article: Dobros K, Hajto-Bryk J, Wnęk A, Zarzecka J, Rzepka D. The level of dental anxiety and dental status in adult patients. J Int Oral Health 2014;6(3):11-4. PMID:25083026

  2. Exploiting the higher specificity of silver amalgamation: selective detection of mercury(II) by forming Ag/Hg amalgam.

    PubMed

    Deng, Li; Ouyang, Xiangyuan; Jin, Jianyu; Ma, Cheng; Jiang, Ying; Zheng, Jing; Li, Jishan; Li, Yinhui; Tan, Weihong; Yang, Ronghua

    2013-09-17

    Heavy metal ion pollution poses severe risks in human health and the environment. Driven by the need to detect trace amounts of mercury, this article demonstrates, for the first time, that silver/mercury amalgamation, combining with DNA-protected silver nanoparticles (AgNPs), can be used for rapid, easy and reliable screening of Hg(2+) ions with high sensitivity and selectivity over competing analytes. In our proposed approach, Hg(2+) detection is achieved by reducing the mercury species to elemental mercury, silver atoms were chosen as the mercury atoms' acceptors by forming Ag/Hg amalgam. To signal fluorescently this silver amalgamation event, a FAM-labeled ssDNA was employed as the signal reporter. AgNPs were grown on the DNA strand that resulted in greatly quenching the FAM fluorescence. Formation of Ag/Hg amalgam suppresses AgNPs growth on the DNA, leading to fluorescence signal increase relative to the fluorescence without Hg(2+) ions, as well as marked by fluorescence quenching. This FAM fluorescence enhancement can be used for detection of Hg(2+) at the a few nanomolar level. Moreover, due to excellent specificity of silver amalgamation with mercury, the sensing system is highly selective for Hg(2+) and does not respond to other metal ions with up to millimolar concentration levels. This sensor is successfully applied to determination of Hg(2+) in tap water, spring water and river water samples. The results shown herein have important implications in the development of new fluorescent sensors for the fast, easy, and selective detection and quantification of Hg(2+) in environmental and biological samples. PMID:23937672

  3. Dental Hygienist.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. Center on Education and Training for Employment.

    This document, which is designed for use in developing a tech prep competency profile for the occupation of dental hygienist, lists technical competencies and competency builders for 13 units pertinent to the health technologies cluster in general and 9 units specific to the occupation of dental hygienist. The following skill areas are covered in…

  4. Dental Implants.

    PubMed

    Zohrabian, Vahe M; Sonick, Michael; Hwang, Debby; Abrahams, James J

    2015-10-01

    Dental implants restore function to near normal in partially or completely edentulous patients. A root-form implant is the most frequently used type of dental implant today. The basis for dental implants is osseointegration, in which osteoblasts grow and directly integrate with the surface of titanium posts surgically embedded into the jaw. Radiologic assessment is critical in the preoperative evaluation of the dental implant patient, as the exact height, width, and contour of the alveolar ridge must be determined. Moreover, the precise locations of the maxillary sinuses and mandibular canals, as well as their relationships to the site of implant surgery must be ascertained. As such, radiologists must be familiar with implant design and surgical placement, as well as augmentation procedures utilized in those patients with insufficient bone in the maxilla and mandible to support dental implants.

  5. Allergic Reactions to Dental Materials-A Systematic Review

    PubMed Central

    Chopra, Radhika; Sachdev, Vinod

    2015-01-01

    Introduction Utility of various dental materials ranging from diagnosis to rehabilitation for the management of oral diseases are not devoid of posing a potential risk of inducing allergic reactions to the patient, technician and dentist. This review aims to develop a systematic approach for the selection and monitoring of dental materials available in the market thereby giving an insight to predict their risk of inducing allergic reactions. Materials and Methods Our data included 71 relevant articles which included 60 case reports, 8 prospective studies and 3 retrospective studies. The source of these articles was Pub Med search done with the following terms: allergies to impression materials, sodium hypochlorite, Ledermix paste, zinc oxide eugenol, formaldehyde, Latex gloves, Methyl methacrylate, fissure sealant, composites, mercury, Nickel-chromium, Titanium, polishing paste and local anaesthesia. All the relevant articles and their references were analysed. The clinical manifestations of allergy to different dental materials based on different case reports were reviewed. Results After reviewing the literature, we found that the dental material reported to cause most adverse reactions in patients is amalgam and the incidence of oral lichenoid reactions adjacent to amalgam restorations occur more often than other dental materials. Conclusion The most common allergic reactions in dental staff are allergies to latex, acrylates and formaldehyde. While polymethylmethacrylates and latex trigger delayed hypersensitivity reactions, sodium metabisulphite and nickel cause immediate reactions. Over the last few years, due to the rise in number of patients with allergies from different materials, the practicing dentists should have knowledge about documented allergies to known materials and thus avoid such allergic manifestations in the dental clinic. PMID:26557634

  6. A model for amalgamation in group decision making

    NASA Technical Reports Server (NTRS)

    Cutello, Vincenzo; Montero, Javier

    1992-01-01

    In this paper we present a generalization of the model proposed by Montero, by allowing non-complete fuzzy binary relations for individuals. A degree of unsatisfaction can be defined in this case, suggesting that any democratic aggregation rule should take into account not only ethical conditions or some degree of rationality in the amalgamating procedure, but also a minimum support for the set of alternatives subject to the group analysis.

  7. Dental OCT

    NASA Astrophysics Data System (ADS)

    Wilder-Smith, Petra; Otis, Linda; Zhang, Jun; Chen, Zhongping

    This chapter describes the applications of OCT for imaging in vivo dental and oral tissue. The oral cavity is a diverse environment that includes oral mucosa, gingival tissues, teeth and their supporting structures. Because OCT can image both hard and soft tissues of the oral cavity at high resolution, it offers the unique capacity to identity dental disease before destructive changes have progressed. OCT images depict clinically important anatomical features such as the location of soft tissue attachments, morphological changes in gingival tissue, tooth decay, enamel thickness and decay, as well as the structural integrity of dental restorations. OCT imaging allows for earlier intervention than is possible with current diagnostic modalities.

  8. Mechanical retention versus bonding of amalgam and gallium alloy restorations.

    PubMed

    Eakle, W S; Staninec, M; Yip, R L; Chavez, M A

    1994-10-01

    The retention of amalgam and gallium alloy restorations in proximal box forms was measured in vitro, and three different adhesives to conventional undercuts were compared. For control, restorations were placed without undercuts or adhesives. No significant difference was found between amalgam and gallium alloys with each of the five methods of retention used. Alloys placed without retention or adhesives were significantly less retentive than all other groups. When Tytin alloy was used, no difference was found in retention among the restorations retained with Panavia or All-Bond adhesive or an occlusal dovetail and retention grooves, but Amalgambond adhesive was less retentive than all three of these methods. When gallium alloy was used, both Panavia and All-Bond adhesive were more retentive than undercuts, but the effect of Amalgambond adhesive was more retentive than undercuts, but the effect of Amalgambond adhesive was comparable to that of undercuts. The results of this study indicate that adhesives could be used in place of traditional undercuts to retain amalgam and gallium alloys, thus saving a considerable amount of tooth structure. PMID:7990038

  9. Effect of various zinc oxide materials as root-end fillings on healing after replantation.

    PubMed

    Pitt Ford, T R; Andreasen, J O; Dorn, S O; Kariyawasam, S P

    1995-11-01

    This study examined the effect of various zinc oxide materials as root-end fillings of teeth in a replantation model. A total of 35 molar teeth were used from 19 monkeys. After extraction, root ends were resected, the canals contaminated with oral bacteria, root-end cavities prepared and fillings placed prior to replantation. After 8 weeks the teeth and surrounding jaw were removed and prepared for histological examination. Twelve roots were filled with IRM plus dentine chips, and six with Cavit; the tissue response around root ends filled with these materials as assessed by inflammation was similar to that previous reported to IRM and Super EBA cement and was characterized by little or no inflammation of limited extent. In contrast, more severe inflammation was observed around root ends filled with plain zinc oxide-eugenol or Kalzinol; however, the reaction was neither as severe nor as extensive as that to amalgam root-end fillings. Giant cells were observed most often on the surface of fillings with Cavit and zinc oxide-eugenol. It is concluded that the tissue response to IRM with or without added dentine, Super EBA and Cavit was similar and mild; it was less severe than that to zinc oxide-eugenol and Kalzinol. All these materials had a much more favourable response than amalgam

  10. Amalgam components drift in teeth-toxicity risks: A preliminary approach

    NASA Astrophysics Data System (ADS)

    Carvalho, M. L.; Pinheiro, T.; Barreiros, M. A.; Casaca, C.; Cunha, A. S.; Chevallier, P.

    1998-03-01

    The use of ion beam techniques applied to teeth studies have been extensive in what concerns the major elements distribution. However, it is not clarified whether amalgam components are absorbed and drifted through teeth material, although the toxicity of the elements used in amalgams, such as Hg, are well known. This work is an attempt to assess a possible teeth contamination originated by the amalgams. Therefore, teeth with metallic amalgam, as well as healthy ones, were studied. The teeth were longitudinally cut and each slice was scanned from the inner region to the surface enamel for elemental profiles determination purposes using Particle Induced X-ray Emission (PIXE) and Synchrotron Radiation X-ray Fluorescence (SRXRF) techniques. High levels of Zn, Ag, Sn, Hg and Pb were found along the scanned teeth restored with the metallic amalgam. The elemental distribution patterns suggest diffusion of these elements in the teeth material from amalgam constituents.

  11. Dental Fluorosis

    MedlinePlus

    ... when children regularly consume fluoride during the teeth-forming years, age 8 and younger. Most dental fluorosis ... over a long period when the teeth are forming under the gums. Only children aged 8 years ...

  12. Bond strength of resin composite to differently conditioned amalgam.

    PubMed

    Ozcan, M; Vallittu, P K; Huysmans, M-C; Kalk, W; Vahlberg, T

    2006-01-01

    Bulk fracture of teeth, where a part of the amalgam restoration and/or the cusp is fractured, is a common clinical problem. The aim of this study was to evaluate the effect of different surface conditioning methods on the shear bond strength of a hybrid resin composite to fresh amalgam. Amalgams (N=84) were condensed into acrylic and randomly assigned to one of the following treatments (N=6): (1) Alloy primer + opaquer, (2) Air-particle abrasion (50 micro m Al(2)O(3)) + alloy primer + opaquer, (3) Silica coating (30 micro m SiO(x)) + silanization + opaquer, (4) Opaquer + pre-impregnated continuous bidirectional E-glass fibre sheets, (5) Silica coating + silanization + fibre sheets, (6) Silica coating + silanization + opaquer + fibre sheet application. Non-conditioned amalgam surfaces were considered as control group (7). The mean surface roughness depth (R(Z)) was measured from the control group and air-abraded amalgam surfaces. The resin composite was bonded to the conditioned amalgam specimens using polyethylene molds. All specimens were tested under dry and thermocycled (6.000, 5-55 degrees C, 30 s) conditions. The shear bond strength of resin composite to amalgam substrates was measured in a universal testing machine (1 mm/min). Surface roughness values for the non-conditioned control group (R(Z) approximately 0.14 micro m) and for air-particle abraded surfaces with either Al(2)O(3) or SiO(x) (R(Z) approximately 0.19 micro m and R(Z) approximately 0.16 micro m, respectively) did not show significant differences (p=0.23) (One-way ANOVA). In dry conditions, silica coating and silanization followed by fibre sheet application exhibited significantly higher results (14.8+/-5.6 MPa) than those of the groups conditioned with alloy primer (2.2+/-0.7 MPa) (p<0.001), air-particle abrasion+alloy primer (4.4+/-2.0 MPa, p<0.001), silica coating+silanization alone (6.2+/-0.8 MPa, p=0.009) or non-conditioned group (1.4+/-0.6, p<0.001). Silica coating and silanization followed

  13. A 3-year randomized clinical trial evaluating two different bonded posterior restorations: Amalgam versus resin composite

    PubMed Central

    Kemaloglu, Hande; Pamir, Tijen; Tezel, Huseyin

    2016-01-01

    Objective: To compare the performance and postoperative sensitivity of a posterior resin composite with that of bonded amalgam in 40 (n = 20) large sized cavities and to evaluate whether resin composite could be an alternative for bonded amalgam. Materials and Methods: This was a randomized clinical trial. Twenty patients in need of at least two posterior restorations were recruited. Authors randomly assigned one half of the restorations to receive bonded amalgam and the other half to composite restorations. Forty bonded amalgams (n = 20) and composites (n = 20) were evaluated for their performance on modified-US Public Health Service criteria and postoperative sensitivity using visual analogue scale (VAS) for 36-months. Results: Success rate of this study was 100%. First clinical alterations were rated as Bravo after 1 year in marginal discoloration, marginal adaptation, anatomical form, and surface roughness for both amalgam and composite. At the 3rd year, overall “Bravo” rated restorations were 12 for bonded amalgam and 13 for resin composites. There were no significant differences among the VAS scores of composites and bonded amalgams for all periods (P > 0.05) except for the comparisons at the 3rd year evaluation (P < 0.05). Conclusions: Within the limitation of this study, both resin composite and bonded amalgam were clinically acceptable. Postoperative sensitivity results tend to decrease more in composite restorations rather than amalgams. Therefore, it was concluded that posterior resin composite can be used even in large sized cavities. PMID:27011734

  14. Dental Care for a Child with Cleft Lip and Palate

    MedlinePlus

    ... will need fillings or removal of a tooth. Orthodontic Care The first orthodontic evaluation may be scheduled even before the child ... of the permanent teeth, the final phase of orthodontics completes alignment of the teeth. Coordinated Dental-Surgical ...

  15. Visibility of dental pulp spaces in dental ultrasound.

    PubMed

    Szopinski, K T; Regulski, P

    2014-01-01

    The purpose of this study was to assess the feasibility of dental ultrasound with conventional sonographic equipment. The teeth of three adult volunteers who had cone beam CT examinations performed previously with clinical indications and one extracted tooth were examined using linear and compact (hockey stick) sonographic probes. The sonographic images were compared with cone beam CT images reconstructed accordingly. Dental pulp spaces were demonstrated in all teeth not covered with prosthetic crowns. The dentin and pulp were best visualized at the level of the neck of the teeth. The dentin was hypoechoic, and the superficial layer comprising the cementum and the pulp spaces were hyperechoic. Dental ultrasound is feasible with general purpose sonographic machines. The buccal surfaces of all teeth are accessible with a compact (hockey stick) probe. Visualization and differentiation of dental pulp spaces, dentin and the superficial layer comprising cementum is possible in the portions of teeth not covered by the alveolar bone or prosthetic crowns. The dental pulp spaces are best seen at the level of the tooth neck. Pulp and endodontic fillings can be distinguished on ultrasound.

  16. Visibility of dental pulp spaces in dental ultrasound

    PubMed Central

    Szopinski, K T; Regulski, P

    2014-01-01

    The purpose of this study was to assess the feasibility of dental ultrasound with conventional sonographic equipment. The teeth of three adult volunteers who had cone beam CT examinations performed previously with clinical indications and one extracted tooth were examined using linear and compact (hockey stick) sonographic probes. The sonographic images were compared with cone beam CT images reconstructed accordingly. Dental pulp spaces were demonstrated in all teeth not covered with prosthetic crowns. The dentin and pulp were best visualized at the level of the neck of the teeth. The dentin was hypoechoic, and the superficial layer comprising the cementum and the pulp spaces were hyperechoic. Dental ultrasound is feasible with general purpose sonographic machines. The buccal surfaces of all teeth are accessible with a compact (hockey stick) probe. Visualization and differentiation of dental pulp spaces, dentin and the superficial layer comprising cementum is possible in the portions of teeth not covered by the alveolar bone or prosthetic crowns. The dental pulp spaces are best seen at the level of the tooth neck. Pulp and endodontic fillings can be distinguished on ultrasound. PMID:24170803

  17. Rondeau Seminars amalgamated mid-sagittal (lateral) cephalometric analysis.

    PubMed

    Palencar, Adrian J

    2014-01-01

    The author presents a comprehensive International Association for Orthodontics--Rondeau Seminars Amalgamated Mid-sagittal (Lateral) Cephalometric Analysis. Norms on the Cephalometric Data Sheet are age and gender specific for the Caucasian population and the postings are color coded for visual attraction. If the patient is ofa different ethnic group, the Norms should be adjusted accordingly. This Cephalometric Analysis is comprised often Sections, in alphabetical order and twenty nine Factors. The author expanded Rondeau Seminars Cephalometric Analysis by only six Factors, thus fulfilling the requirement for the case presentation for the Fellow of the IAO and the Diplomate ofthe IBO.

  18. Dental surgery in ancient Egypt.

    PubMed

    Blomstedt, Patric

    2013-01-01

    Many different surgical procedures have over the years been attributed to the ancient Egyptians. This is also true regarding the field of dental surgery. The existence of dentists in ancient Egypt is documented and several recipes exist concerning dental conditions. However, no indications of dental surgery are found in the medical papyri or in the visual arts. Regarding the osteological material/mummies, the possible indications of dental surgery are few and weak. There is not a single example of a clear tooth extraction, nor of a filling or of an artificial tooth. The suggested examples of evacuation of apical abscesses can be more readily explained as outflow sinuses. Regarding the suggested bridges, these are constituted of one find likely dating to the Old Kingdom, and one possibly, but perhaps more likely, dating to the Ptolemaic era. Both seem to be too weak to have served any possible practical purpose in a living patient, and the most likely explanation would be to consider them as a restoration performed during the mummification process. Thus, while a form of dentistry did certainly exist in ancient Egypt, there is today no evidence of dental surgery.

  19. Do Laboratory Results Concerning High-Viscosity Glass-Ionomers versus Amalgam for Tooth Restorations Indicate Similar Effect Direction and Magnitude than that of Controlled Clinical Trials? - A Meta-Epidemiological Study

    PubMed Central

    Mickenautsch, Steffen; Yengopal, Veerasamy

    2015-01-01

    Background A large percentage of evidence concerning dental interventions is based on laboratory research. The apparent wealth of laboratory evidence is sometimes used as basis for clinical inference and recommendations for daily dental practice. In this study two null-hypotheses are tested: whether trial results from laboratory and controlled clinical trials concerning the comparison of high-viscosity glass-ionomer cements (HVGIC) to amalgam for restorations placed in permanent posterior teeth have: (i) similar effect direction and (ii) similar effect magnitude. Methods 7 electronic databases were searched, as well as reference lists. Odds ratios (OR) and Standardised Mean Differences (SMD) with 95% Confidence intervals were computed for extracted dichotomous and continuous data, respectively. Pooled effect estimates for laboratory and clinical data were computed to test for effect direction. Odds ratios were converted into SMDs. SMDs from laboratory and clinical data were statistically compared to test for differences in effect magnitude. The analysed results were further investigated within the context of potential influencing or confounding factors using a Directed acyclic graph. Results Of the accepted eight laboratory and nine clinical trials, 13 and 21 datasets could be extracted, respectively. The pooled results of the laboratory datasets were highly statistically significant in favor of amalgam. No statistically significant differences, between HVGICs and amalgam, were identified for clinical data. For effect magnitude, statistically significant differences between clinical and laboratory trial results were found. Both null-hypotheses were rejected. Conclusion Laboratory results concerning high-viscosity glass-ionomers versus amalgam for tooth restorations do not indicate similar effect direction and magnitude than that of controlled clinical trials. PMID:26168274

  20. EDS and μ-XRF mapping of amalgam degradation products in ancient mirrors.

    PubMed

    Arizio, E; Orsega, E F; Falcone, R; Vallotto, M

    2014-12-01

    An amalgam mirror is a mirror type, used from the fifteenth century until the end of the nineteenth century, where the reflective layer is constituted by a tin amalgam layer adhered to a glass sheet. In this work, two amalgam mirrors samples were studied by scanning electron microscopy with an energy dispersive spectrometer and by micro-X-ray fluorescence elemental mapping to go deeply into the understanding of the degradation mechanism of the amalgam layer of ancient mirrors. The investigation has been focused for the first time on the reflective surface of the amalgam layer adherent to the glass sheet to better understand the processes of amalgam corrosion. The two amalgam degradation compounds, romarchite and cassiterite, has been spatially differentiated by scanning electron microscope (SEM) and energy dispersive spectrometer (EDS) maps. SEM images and micro-X-ray fluorescence and EDS maps showed that the amalgam degradation products grow up to form hemispherical stratified calottes. This structure is probably due to a mechanism involves cyclic phases and oxygen radial diffusion from a superficial oxidation nucleus.

  1. 21 CFR 872.3310 - Coating material for resin fillings.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Coating material for resin fillings. 872.3310 Section 872.3310 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3310 Coating material for resin...

  2. Galvanic corrosion and cytotoxic effects of amalgam and gallium alloys coupled to titanium.

    PubMed

    Bumgardner, J D; Johansson, B I

    1996-06-01

    The aim of this study was to examine and compare the galvanic corrosion of a conventional, a dispersed high-copper, and a palladium-enriched spherical high-copper amalgam and a gallium alloy coupled to titanium in saline and cell culture solutions, and to evaluate the effects of the couples on cultured cells. The potentials and charge transfers between amalgams and titanium were measured by electrochemical corrosion methods. Cytotoxicity of the couples, as indicated by the uptake of neutral red vital stain, was determined in 24-h direct contact human gingival fibroblast cell cultures. Results of this study indicated that before connecting the high-copper amalgams to titanium, the amalgams exhibited more positive potentials which resulted in initial negative charge transfers, i.e. corrosion of titanium. However, this initial corrosion appeared to cause titanium to passivate, and a shift in galvanic currents to positive charge transfers, i.e. corrosion of the amalgam samples. Lower galvanic currents were measured for the amalgam-titanium couples as compared to the gallium alloy-titanium couple. Coupling the conventional or the palladium-enriched high-copper amalgams to titanium did not significantly affect the uptake of neutral red as compared to cells not exposed to any test alloy. However, significant cytotoxic effects were observed when the dispersed-type high-copper amalgam and the gallium alloy were coupled to titanium. Even though the corrosion currents measured for these couples were less than gold alloys coupled to amalgam, these results suggest there is the potential for released galvanic corrosion products to become cytotoxic. These data warrant further investigations into the effects of coupling amalgam and gallium alloys to titanium in the oral environment.

  3. Dental Assistant.

    ERIC Educational Resources Information Center

    Michigan State Univ., East Lansing. Coll. of Agriculture and Natural Resources Education Inst.

    This curriculum guide, developed for use in dental assistant education programs in Michigan, describes a task-based curriculum that can help a teacher to develop a classroom management system where students learn by doing. It is based on task analysis and reflects the skills, knowledge, and attitudes that employers expect entry-level dental…

  4. Biocompatibility of root-end filling materials: recent update

    PubMed Central

    Gupta, Saurabh Kumar; Newaskar, Vilas

    2013-01-01

    The purpose of a root-end filling is to establish a seal between the root canal space and the periradicular tissues. As root-end filling materials come into contact with periradicular tissues, knowledge of the tissue response is crucial. Almost every available dental restorative material has been suggested as the root-end material of choice at a certain point in the past. This literature review on root-end filling materials will evaluate and comparatively analyse the biocompatibility and tissue response to these products, with primary focus on newly introduced materials. PMID:24010077

  5. An investigation of the microstructure and mechanical properties of electrochemically coated Ag(4)Sn dental alloy particles condensed in vitro

    NASA Astrophysics Data System (ADS)

    Marquez, Jose Antonio

    As part of the ongoing scientific effort to develop a new amalgam-like material without mercury, a team of metallurgists and electrochemists at the National Institute of Standards and Technology (NIST) in Gaithersburg, Maryland, announced in 1993 the development of a new Ag-Sn dental alloy system without mercury that sought to replace conventional dental amalgams. They used spherical Ag3Sn and Ag4Sn intermetallic dental alloy particles, commonly used in conventional dental alloys, and coated them with electrodeposited silver with newly-developed electrolytic and immersion techniques. The particles had relatively pure silver coatings that were closely adherent to the intermetalfic cores. These silver-coated particles, due to silver's plasticity at room temperature, were condensed into PlexiglasRTM molds with the aid of an acidic surface activating solution (HBF4) and a mechanical condensing device, producing a metal-matrix composite with Ag3,4Sn filler particles surrounded by a cold-welded silver matrix. Since silver strain hardens rather easily, the layers had to be condensed in less than 0.5 mm increments to obtain a dense structure. Mechanical testing at NIST produced compressive strength values equal to or greater than those of conventional dental amalgams. Because of its potential for eliminating mercury as a constituent in dental amalgam, this material created a stir in dental circles when first developed and conceivably could prove to be a major breakthrough in the field of dental restoratives. To date, the chief impediments to its approval for human clinical applications by the Food and Drug Administration are the potentially-toxic surface activating solution used for oxide reduction, and the high condensation pressures needed for cold welding because of the tendency for silver to strain harden. In this related study, the author, who has practiced general dentistry for 25 years, evaluates some of the mechanical and microstructural properties of these

  6. Dental Training Films.

    ERIC Educational Resources Information Center

    Veterans Administration Medical Center, Washington, DC.

    This dental training films catalog is organized into two sections. Section I is a category listing of the films by number and title, indexed according to generalized headings; categories are as follow: anatomy, articulator systems, complete dentures, dental assisting, dental laboratory technology, dental materials, dental office emergencies,…

  7. Tissue response to potential root-end filling materials in infected root canals.

    PubMed

    Chong, B S; Ford, T R; Kariyawasam, S P

    1997-03-01

    The tissue responses to two potential root-end filling materials, a light-cured glass ionomer cement (Vitrebond) and a reinforced zinc oxide-eugenol cement (Kalzinol) were compared with that to amalgam. In 27 premolar teeth of beagle dogs (54 roots), a collection of endodontic pathogenic bacteria was first inoculated into the root canals to induce periapical lesions. On each root, an apicectomy was performed and root-end cavities prepared to receive fillings of each material. The teeth and surrounding jaw were removed after 8 weeks (24 roots) and 4 weeks (30 roots); and they were prepared for histological examination. The tissue response to amalgam fillings after 4 and 8 weeks was marked by moderate or severe inflammation on all roots, and extended > 0.5 mm in 10 out of 18 roots. In contrast, after 8 weeks, the majority of roots filled with Kalzinol showed little or moderate inflammation while the tissue response to Vitrebond was the best of the three materials, and was also less extensive. After 4 weeks, the overall best tissue response was with Kalzinol, followed closely by Vitrebond. The differences between materials for both time periods with either none or few inflammatory cells when compared with that with either moderate or severe inflammation were statistically significant (P < 0.01). Similarly, the differences between materials for both time periods with no inflammation or inflammation extending < 0.2 mm when compared with that with inflammation extending > 0.2 mm (< or = 0.5 mm or > 0.5 mm) were statistically significant (P < 0.01). Both Vitrebond and Kalzinol have potential as root-end filling materials as the tissue response was considerably more favourable than that to amalgam.

  8. Pressurized gas filled tendons

    SciTech Connect

    Silcox, W. H.

    1985-06-04

    Pressurized gas filled tubular tendons provide a means for detecting leaks therein. Filling the tendon with a gaseous fluid provides increased buoyancy and reduces the weight supported by the buoyant structure. The use of a corrosion inhibiting gaseous fluid reduces the corrosion of the interior tendon wall.

  9. [Validity of decision criteria for replacement of fillings].

    PubMed

    Hannig, Christian; Kupilas, Florian Jan; Wolkewitz, Martin; Attin, Thomas

    2009-01-01

    One of the main treatments in dental practice is the exchange of restorations due to secondary or residual caries. Thereby, only restorations indeed infected with secondary or residual caries should be renewed. The aim of the study was to check the validity of different criteria for the replacement of fillings. Three hundred seventeen replacements of dental restorations were evaluated retrospectively by using an examination form. Different clinical parameters were correlated with the finding of caries after removal of the old restoration. Clinical findings were differentiated between caries soft to probing, caries only stainable with caries detector and caries-free cavities. Sixty-seven percent of the cavities showed caries that could be probed, 16.1% were just stainable with caries detector and 17% were caries-free. In general, results of previous replacements of fillings were a valid criterion. Other indicators for caries-free cavities were properly placed fillings with a correctly reconstructed morphology, fillings without marginal defects, a low age of the filling and a positive impression of the patients' general hygiene. Indicators for cavities with secondary caries were marginal gaps, pain within the respective section of the jaw, a high number of filled surfaces and a bad impression of the general hygiene. Systematic diagnostic criteria should be adopted in decision making on replacement of fillings in order to avoid new restorations of caries-free cavities.

  10. Synchrotron-radiation-based X-ray micro-computed tomography reveals dental bur debris under dental composite restorations.

    PubMed

    Hedayat, Assem; Nagy, Nicole; Packota, Garnet; Monteith, Judy; Allen, Darcy; Wysokinski, Tomasz; Zhu, Ning

    2016-05-01

    Dental burs are used extensively in dentistry to mechanically prepare tooth structures for restorations (fillings), yet little has been reported on the bur debris left behind in the teeth, and whether it poses potential health risks to patients. Here it is aimed to image dental bur debris under dental fillings, and allude to the potential health hazards that can be caused by this debris when left in direct contact with the biological surroundings, specifically when the debris is made of a non-biocompatible material. Non-destructive micro-computed tomography using the BioMedical Imaging & Therapy facility 05ID-2 beamline at the Canadian Light Source was pursued at 50 keV and at a pixel size of 4 µm to image dental bur fragments under a composite resin dental filling. The bur's cutting edges that produced the fragment were also chemically analyzed. The technique revealed dental bur fragments of different sizes in different locations on the floor of the prepared surface of the teeth and under the filling, which places them in direct contact with the dentinal tubules and the dentinal fluid circulating within them. Dispersive X-ray spectroscopy elemental analysis of the dental bur edges revealed that the fragments are made of tungsten carbide-cobalt, which is bio-incompatible.

  11. Sudden hearing loss after dental treatment.

    PubMed

    Kansu, Leyla; Yilmaz, Ismail

    2013-08-01

    A 66-year-old man presented with impaired balance, tinnitus, sensation of blockage, and hearing loss in his left ear, which developed after dental treatment for dental pain 4 days previously. Treatment of the carious left upper second molar tooth had included pulp extirpation, canal expansion, and tooth filling under local anesthesia with articaine and epinephrine. Impaired balance decreased spontaneously within 3 days of dental treatment, but tinnitus and hearing loss persisted. Pure tone audiogram showed profound sensorineural hearing loss in the left ear, with a downslope from 40 to 100 dB, and an abnormal speech discrimination score (50%). Treatment included intravenous prednisolone, intratympanic dexamethasone, and oral betahistine and trimetazidine. The patient had improved hearing and resolution of tinnitus. Sudden hearing loss is rare after dental treatment, and awareness of this complication may prompt early referral for treatment and may improve recovery and prognosis.

  12. Sudden hearing loss after dental treatment.

    PubMed

    Kansu, Leyla; Yilmaz, Ismail

    2013-08-01

    A 66-year-old man presented with impaired balance, tinnitus, sensation of blockage, and hearing loss in his left ear, which developed after dental treatment for dental pain 4 days previously. Treatment of the carious left upper second molar tooth had included pulp extirpation, canal expansion, and tooth filling under local anesthesia with articaine and epinephrine. Impaired balance decreased spontaneously within 3 days of dental treatment, but tinnitus and hearing loss persisted. Pure tone audiogram showed profound sensorineural hearing loss in the left ear, with a downslope from 40 to 100 dB, and an abnormal speech discrimination score (50%). Treatment included intravenous prednisolone, intratympanic dexamethasone, and oral betahistine and trimetazidine. The patient had improved hearing and resolution of tinnitus. Sudden hearing loss is rare after dental treatment, and awareness of this complication may prompt early referral for treatment and may improve recovery and prognosis. PMID:23642550

  13. Attitudes of some European dental undergraduate students to the placement of direct restorative materials in posterior teeth.

    PubMed

    Lynch, C D; Guillem, S E; Nagrani, B; Gilmour, A S M; Ericson, D

    2010-12-01

    The aim of this article was to report on the attitudes, opinions and confidences of final year dental students in three European schools towards the restoration of posterior teeth and in particular towards the use of amalgam and resin composite. One hundred and twenty-eight pre-piloted questionnaires were distributed to final year dental students in Cardiff, Dublin and Malmö. The questionnaire sought information relating to various opinions and attitudes towards the use of amalgam and resin composite in posterior teeth. Information was returned anonymously. Ninety-one completed questionnaires were returned (response rate=71%; Cardiff: n =40, Dublin: n=24, Malmö: n=27). Ninety-three per cent of Malmö students (n=24), 67% of Dublin students (n=16) and 60% of Cardiff students (n=24) reported that they feel confident when placing posterior resin composites. One hundred per cent of Malmö students (n=27), 75% of Cardiff students (n=30) and 33% of Dublin students (n=8) would prefer to have a resin composite rather than amalgam, placed in one of their own posterior teeth. Eighty-five per cent of Malmö students (n=23), 30% of Cardiff students (n=12) and 25% of Dublin students (n=6) perceive amalgam as being harmful to the environment. For the restoration of a posterior tooth in a pregnant female, 44% of students (n=40) would place a resin composite restoration, and 7% (n=6) would place an amalgam restoration, while 32% (n=29) would place a temporary restoration. Students at Malmö report that they place more posterior resin composites and have greater confidence at placing posterior resin composites than students at Cardiff or Dublin. There was confusion relating to the choice of restorative materials for pregnant females. Large variations in restorative strategies among graduates must be considered as dental professionals can practice in all countries within the European Union.

  14. Dental practice in Paris.

    PubMed

    Baron, Pierre

    2003-01-01

    This describes dental practice and the availability of dental patent remedies in Paris. Accounts of legal disputes, from original sources, illustrate the status and social history of some of the most wealthy dental practitioners in Paris during the Revolution.

  15. American Dental Association

    MedlinePlus

    ... Public Prevention Summit ADA Find-a-Dentist Health Literacy in Dentistry Volunteer Efforts Dental Benefit Plan Information ... on Sleep Bruxism Rethinking Dental Insurance Oral Health Literacy's Role in Missed Appointments Dental Implant Failure Rate ...

  16. Effect of inhibitory species on electrochemical corrosion of high copper amalgam.

    PubMed

    Naguib, E A

    1994-07-01

    This investigation evaluates the corrosion potential of high copper amalgam containing inhibitory species, sodium phosphate and sodium citrate, in artificial saliva at different pH levels. The data revealed that the phosphate incorporated in high copper amalgam leads to increase in passivation of the alloy as compared to less or even negative effect of citrate incorporation. The linear steady potential of the amalgam was closer to the reversible potentials corresponding to hydrogen evolution and tin oxide formation. The corrosion potential does not respond reversibly to pH of the saliva solution due to the pronounced passivation of the high pH levels. PMID:9588156

  17. Chemical or microbiological models of secondary caries development around different dental restorative materials.

    PubMed

    Lobo, Maristela M; Gonçalves, Reginaldo B; Ambrosano, Gláucia Maria B; Pimenta, Luiz André F

    2005-08-01

    This study evaluated artificial secondary caries around restorative materials, induced by means of chemical or microbiological models. The following materials were used randomly to restore 130 dental blocks: (1) zinc-oxide eugenol-free temporary filling: Coltosol (Coltène/Whaledent Inc.; n = 30), (2) silver amalgam: Permite C (SDI Limited, n = 20), (3) composite resin: Filtek Z250 (3M ESPE; n = 20), (4) glass-ionomer cement: Fuji II (GC America Inc.; n = 20), (5) resin-modified glass ionomer: Vitremer (3M ESPE; n = 20), and (6) polyacid modified resin: Dyract AP (Dentsply; n = 20). Ten specimens of Group 1 were kept in humidity, and had no carious formation (NC). Ten specimens of each group were submitted to pH cycling (CG, n = 60), and the others were immersed in a medium containing Streptococcus mutans and sucrose (BG, n = 60). Mineral content was determined by microhardness assessment, and lesion depth was measured in polarized light photomicrographs. In the chemical model (CG), mineral content values in the vicinities of restoration were high for Groups 5 (75.7 +/- 11.9), 4 (70.8 +/- 14.2), and NC (95.4 +/- 3.8); intermediate for Groups 1 (55.8 +/- 18.5), 6 (45.6 +/- 11.0), and 2 (44.3 +/- 11.2); and reduced for Group 3 (34.7 +/- 9.7). In the microbiological model (BG), results were similar to CG, although there was less demineralization. The highest lesion depths were found for Groups 3 (182.3 +/- 33.2) in CG and 6 (126.5 +/- 42.8) in BG, when compared to Group 5 (114.6 +/- 26.0 and 56.2 +/- 33.2, respectively). In both models of caries induction, ionomeric materials showed a superior cariostatic effect when compared to the other restorative materials.

  18. Short-term tissue response to potential root-end filling materials in infected root canals.

    PubMed

    Chong, B S; Pitt Ford, T R; Kariyawasam, S P

    1997-07-01

    The short-term tissue responses to two potential root-end filling materials, a light-cured glass ionomer cement (Vitrebond) and a reinforced zinc oxide-eugenol cement (Kalzinol), were compared with that to amalgam using a previously devised experimental model. In 24 premolar teeth of beagle dogs (47 roots), a collection of endodontic pathogenic bacteria was first inoculated into the root canals to induce periradicular lesions. On each root, an apicoectomy was performed and root-end cavities prepared to receive fillings of each material. The teeth and surrounding jaw were removed after 2 weeks (23 roots) and 1 week (24 roots); they were then prepared for histological examination. The tissue response to amalgam fillings after 2 weeks and 1 week was marked by moderate or severe inflammation on all roots, and extended to < or = 0.5 mm or > 0.5 mm in 15 out of 16 roots. In contrast, after 2 weeks, the majority of roots filled with Kalzinol showed little or moderate inflammation, while the tissue response to Vitrebond was the best of the three materials, and was also the least extensive. After 1 week, the overall best tissue response was with Vitrebond, followed by Kalzinol. The differences between materials for both time periods with either none or few inflammatory cells when compared with that with either moderate or severe inflammation were not statistically significant (P < 0.02). However, the differences between materials for both time periods with no inflammation or inflammation extending < 0.2 mm when compared with that with inflammation extending > 0.2 mm (< or = 0.5 mm or > 0.5 mm) were statistically significant (P < 0.01). Apart from amalgam, in which healing was marked by the persistence of a localized focus of inflammation adjacent to the root-end filling, even though there were intersample variations, there was little overall difference in the temporal and qualitative healing response to Vitrebond and Kalzinol. Both Vitrebond and Kalzinol have potential as

  19. Evaluation of dental waste management in two cities in Palestine.

    PubMed

    Darwish, R O; Al-Khatib, I A

    2006-01-01

    Disposal of dental waste was investigated at 37 randomly selected clinics in Ramallah and AI-Bireh cities: 31 private practices and 6 public/NGO clinics. Dentists were interviewed regarding their disposal of different forms of dental waste. Disinfectants and X-ray processing solution were thrown down the drain. For sharps, 13.5% of dentists used puncture-resistant containers (only in the public/ NGO clinics), 45.9% discarded needles directly in the garbage after being recapped and 40.5% placed the used needles and blades in closed plastic bottles before throwing in the general garbage. Blood-soaked dressings and amalgam waste were also thrown in the garbage. While 10.75% of dentists were vaccinated against hepatitis B, 47% of the staff at private clinics were not.

  20. Getting a prescription filled

    MedlinePlus

    ... to get prescription filled; Pharmacy - mail order; Pharmacy - internet; Types of pharmacies ... stored at certain temperatures at a local pharmacy. INTERNET (ONLINE) PHARMACIES Internet pharmacies can be used for ...

  1. Pyrotechnic filled molding powder

    DOEpatents

    Hartzel, Lawrence W.; Kettling, George E.

    1978-01-01

    The disclosure relates to thermosetting molding compounds and more particularly to a pyrotechnic filled thermosetting compound comprising a blend of unfilled diallyl phthalate molding powder and a pyrotechnic mixture.

  2. Dental students--dental advocates.

    PubMed

    Bensch, Brittany

    2010-01-01

    Student advocacy and involvement in the political process is built into the structure of the American Student Dental Association (ASDA), especially in its Legislative Grassroots Network and an internal communication network among students to ensure political awareness. Students are concerned with such issues as a universally accepted, non-patient-based licensure process, mid-level providers, loan availability and tax deductibility, financial support for schools, and service early in one's professional career (giving forward rather than giving back). Through collaboration with the American Dental Education Association and with many state associations, students participate in lobbying, awareness campaigns, and behind the scenes as legislative aids. Although students share the same love for the profession that animates established practitioners, they are perceived by legislators as being different. Students are involved in the legislative process because it represents their future.

  3. Dental students--dental advocates.

    PubMed

    Bensch, Brittany

    2010-01-01

    Student advocacy and involvement in the political process is built into the structure of the American Student Dental Association (ASDA), especially in its Legislative Grassroots Network and an internal communication network among students to ensure political awareness. Students are concerned with such issues as a universally accepted, non-patient-based licensure process, mid-level providers, loan availability and tax deductibility, financial support for schools, and service early in one's professional career (giving forward rather than giving back). Through collaboration with the American Dental Education Association and with many state associations, students participate in lobbying, awareness campaigns, and behind the scenes as legislative aids. Although students share the same love for the profession that animates established practitioners, they are perceived by legislators as being different. Students are involved in the legislative process because it represents their future. PMID:21314046

  4. Mercury biomarkers and DNA methylation among Michigan dental professionals.

    PubMed

    Goodrich, Jaclyn M; Basu, Niladri; Franzblau, Alfred; Dolinoy, Dana C

    2013-04-01

    Modification of the epigenome may be a mechanism underlying toxicity and disease following chemical exposure. Animal and human data suggest that mercury (Hg) impacts DNA methylation. We hypothesize that methylmercury and inorganic Hg exposures from fish consumption and dental amalgams, respectively, may be associated with altered DNA methylation at global repetitive elements (long interspersed elements, LINE-1) and candidate genes related to epigenetic processes (DNMT1) and protection against Hg toxicity (SEPW1, SEPP1). Dental professionals were recruited at Michigan Dental Association (MDA) meetings in 2009 and 2010. Subjects (n=131) provided survey data (e.g. exposure sources, demographics) and biological samples for Hg measurement and epigenetic analysis. Total Hg was quantified via atomic absorption spectrophotometry in hair and urine, indicative of methylmercury and inorganic Hg exposures, respectively. Global repetitive and candidate gene methylation was quantified via pyrosequencing of bisulfite converted DNA isolated from buccal mucosa. Hair Hg (geometric mean (95% CI): 0.37 (0.31-0.44) µg/g) and urine Hg (0.70 (0.60-0.83) µg/L) were associated with sources of exposure (fish consumption and dental amalgams, respectively). Multivariable linear regression revealed a trend of SEPP1 hypomethylation with increasing hair Hg levels, and this was significant (P<0.05) among males. The trend remained when excluding non-dentists. No significant relationships between urine Hg and DNA methylation were observed. Thus, in a limited cohort, we identified an association between methylmercury exposure and hypomethylation of a potentially labile region of the genome (SEPP1 promoter), and this relationship was gender specific. PMID:23444121

  5. Embryotoxicity assays for leached components from dental restorative materials

    PubMed Central

    2011-01-01

    Background Currently, there are no suitable assays available to evaluate the embryotoxicity of leached components from restorative dental materials. Methods The effect of the medium conditioned by composites and amalgam on mouse blastocysts in vitro was tested. The materials were also subcutaneously implanted, and the effect of the medium supplemented with serum from the host blood was evaluated in the embryotoxicity assay. The embryo implantation rate in the material-transplanted mothers was also evaluated. Results The results show that while the culture in media conditioned by amalgams did not affect blastocyst development, the medium conditioned by composites caused blastocyst degeneration and apoptosis. The development of blastocysts in a medium containing serum obtained from animals after transplantation was, however, without effect. Finally, inconsistent reduction in the implantation rate in transplanted mothers was observed. Conclusions In this study, we provide examples of in vitro and in vivo tests that may be used to evaluate embryotoxicity for dental materials. Our results show that leached components from our composite-material induced embryotoxicity in vitro, however, no toxicity was observed when subcutaneously implanted in vivo. This highlights the necessity of integrated in vitro and in vivo tests for valuable predictive estimation of embryotoxicity for complex materials. PMID:21978455

  6. A clinical evaluation of occlusal composite and amalgam restorations: one- and two-year results.

    PubMed

    Gibson, G B; Richardson, A S; Patton, R E; Waldman, R

    1982-03-01

    A two-year study was conducted to compare the qualitative advantages, if any, of a conventional, cold-curing composite resin to amalgam in occlusal Class I cavities in posterior teeth. The composite was placed into modified, conservative cavity preparations using the acid etch technique. Sixty-one pairs of contralateral restorations were evaluated. Forty-six percent of the amalgams and 42.6% of the composites were considered sound. The major deficiency of each material was rough or chipped margins of the amalgams (38%) and worn surfaces of the composites (26%). The use of conservative cavity preparations and the acid-etch technique with bonding agent and final glaze improved the longevity of the composite restorations compared to previous studies. However, the improvement does not suggest that this method will have a long-term effect on clinical success nor does it indicate that composite is superior to amalgam other than in marginal integrity and esthetics.

  7. DETERMINATION OF TOTAL MERCURY IN FISH TISSUES USING PYROLYSIS ATOMIC ABSORPTION SPECTROMETRY WITH GOLD AMALGAMATION

    EPA Science Inventory

    A simple and rapid procedure for measuring total mercury in fish tissues is evaluated and
    compared with conventional techniques. Using an automated instrument incorporating combustion, preconcentration by amalgamation with gold, and atomic absorption spectrometry (AAS), mill...

  8. Evaluation of Marginal Adaptation of Root-End Filling Materials Using Scanning Electron Microscopy

    PubMed Central

    Oliveira, Helder Fernandes; Gonçalves Alencar, Ana Helena; Poli Figueiredo, José Antônio; Guedes, Orlando Aguirre; de Almeida Decurcio, Daniel; Estrela, Carlos

    2013-01-01

    Introduction The importance of perfect apical seal in endodontics, more specifically in periradicular surgery, is the motivation/reason for development of root-end filling materials with favorable physical, chemical and biological characteristics. The aim of this in vitro study was to evaluate the marginal adaptation of root-end filling materials using scanning electron microscopy. Materials and Methods Twenty five human maxillary anterior teeth were prepared using a K-File #50 to 1 mm short of the apical foramen and filled with gutta-percha and Sealapex using the lateral compaction technique. The apical 3 mm of the roots were sectioned perpendicularly to the long axis of the teeth. A 3-mm-deep root-end cavity was prepared using ultrasonic tips powered by an Enac ultrasonic unit. The teeth were randomly assigned to five groups according to the materials tested including IRM, amalgam, ProRoot MTA, Super-EBA and Epiphany/Resilon. Root-end cavities were filled with the materials prepared according to the manufacturers’ instructions. The root apices were carefully prepared for sputter coating and later evaluation using Scanning Electron Microscope (SEM). The images of root-end fillings were divided into four quadrants and distributed into five categories according to the level of marginal adaptation between the root-end material and the root canal walls. The Fisher exact test with Bonferroni correction was used for statistical analysis. The level of significance was set at P = 0.005. Results SEM images showed the presence of gaps in the root-end filling materials. No significant difference was observed between the tested materials (P > 0.005). Conclusion ProRoot MTA, IRM, amalgam, Super-EBA and Epiphany/Resilon showed similar marginal adaptation as root-end filling materials. PMID:24171026

  9. Cusp Fracture Resistance of Maxillary Premolars Restored with the Bonded Amalgam Technique Using Various Luting Agents

    PubMed Central

    Marchan, Shivaughn M.; Coldero, Larry; White, Daniel; Smith, William A. J.; Rafeek, Reisha N.

    2009-01-01

    Objective. This in vitro study uses measurements of fracture resistance to compare maxillary premolars restored with the bonded amalgam technique using a new resin luting cement, glass ionomer, and resin-modified glass ionomer as the bonding agents. Materials. Eighty-five sound maxillary premolars were selected and randomly assigned to one of five test groups of 17 teeth each. One group of intact teeth served as the control. The remaining groups were prepared to a standard cavity form relative to the dimensions of the overall tooth and restored with amalgam alone or a bonded amalgam using one of three luting agents: RelyX Arc (a new resin luting cement), RelyX luting (a resin-modified glass ionomer), or Ketac-Cem μ (a glass ionomer) as the bonding agents. Each tooth was then subjected to compressive testing until catastrophic failure occurred. The mean loads at failure of each group were statistically compared using ANOVA with a post hoc Bonferroni test. Results. It was found that regardless of the luting cement used for the amalgam bonding technique, there was little effect on the fracture resistance of teeth. Conclusion. Cusp fracture resistance of premolars prepared with conservative MOD cavity preparations is not improved by using an amalgam-bonding technique compared to similar cavities restored with amalgam alone. PMID:20339450

  10. Characterisation of baroque tin amalgam mirrors of the historical Green Vault in Dresden

    NASA Astrophysics Data System (ADS)

    Zywitzki, O.; Nedon, W.; Kopte, T.; Modes, T.

    2008-07-01

    The historical Green Vault, one of Europe’s most sumptuous treasure chambers, has reopened in September 2006 in the Dresden Royal Palace. For the baroque presentation of the artworks the special properties of tin amalgam mirrors are of great importance. A comprehensive analytic characterisation was necessary for restoration and reconstruction. The different original casting glasses were analysed in respect of chemical composition, roughness, waviness and optical properties like chromaticity coordinates and transmittance. The microstructure of the tin amalgam layers were investigated on metallographic cross-sections and by X-ray diffraction. The investigations reveal that the tin amalgam layers are composed of γ-HgSn6-10 phase with a grain size between 5 and 50 μm surrounded by a thin mercury phase with about 2 wt. % tin. However the most important property of the baroque tin amalgam mirrors is a relative low reflectivity of about 59% which is drastically lower than for silver mirrors with a reflectivity of about 96%. According to the characterisation results a suitable glass for reconstruction was selected. The mirror layers were produced by historical tin amalgam technology for the rooms not destroyed by bombarding of Dresden in February 1945. For the completely destroyed Jewel Room pure tin layers were deposited by magnetron sputtering. The results show that this new technology enables an adequate substitute for the original tin amalgam layers.

  11. Reasons for Placement of Restorations on Previously Unrestored Tooth Surfaces by Dental PBRN Dentists

    PubMed Central

    Nascimento, Marcelle M.; Gordan, Valeria V.; Qvist, Vibeke; Litaker, Mark S.; Rindal, D. Brad; Williams, O.D.; Fellows, Jeffrey L.; Ritchie, Lloyd K.; Mjör, Ivar A.; McClelland, Jocelyn; Gilbert, Gregg H.

    2010-01-01

    Objective To identify and quantify the reasons for placing restorations on unrestored permanent tooth surfaces and the dental materials used by Dental Practice-Based Research Network (DPBRN; www.DentalPBRN.org) dentists. Methods A total of 229 DPBRN practitioner-investigators collected data on 9,890 consecutive restorations from 5,810 patients. Information included: (1) reasons for restoring; (2) tooth and surfaces restored; and (3) restorative materials employed. Results Primary caries (85%) and non-carious defects (15%), which included abrasion/ abfraction/ erosion lesions and tooth fracture, were the main reasons for placement of restorations. Restorations due to caries were frequently placed on occlusal surfaces (49%), followed by distal, mesial, buccal/facial, lingual/palatal, and incisal surfaces. Amalgam was used for 46% of the molar and 45% of the premolar restorations. Directly placed resin-based composite (RBC) was used for 48% of the molar, 49% of the premolar, and 92% of the anterior restorations. Conclusion Dental caries on occlusal and proximal surfaces of molar teeth are the main reasons for placing restorations on previously unrestored tooth surfaces by DPBRN practitioner-investigators. RBC is the material most commonly used for occlusal and anterior restorations. Amalgam remains the material of choice to restore proximal caries in posterior teeth, although there are significant differences by DPBRN region. PMID:20354094

  12. Weaker dental enamel explains dental decay.

    PubMed

    Vieira, Alexandre R; Gibson, Carolyn W; Deeley, Kathleen; Xue, Hui; Li, Yong

    2015-01-01

    Dental caries continues to be the most prevalent bacteria-mediated non-contagious disease of humankind. Dental professionals assert the disease can be explained by poor oral hygiene and a diet rich in sugars but this does not account for caries free individuals exposed to the same risk factors. In order to test the hypothesis that amount of amelogenin during enamel development can influence caries susceptibility, we generated multiple strains of mice with varying levels of available amelogenin during dental development. Mechanical tests showed that dental enamel developed with less amelogenin is "weaker" while the dental enamel of animals over-expressing amelogenin appears to be more resistant to acid dissolution.

  13. Dental education in Colombia

    PubMed Central

    Jaramillo, Jorge A.; Pulido, Jairo H. Ternera; Núñez, Jaime A. Castro; Bird, William F.; Komabayashi, Takashi

    2014-01-01

    This article describes Colombia's development of formal dentistry, its dental school system, curriculum, and dental licensure, and current issues in oral health care. In 1969, there were only 4 dental schools in Colombia; at this writing there are 21. Five dental schools are public and the other 16 are private. Nearly all classes are conducted in Spanish. Undergraduate pre-dental coursework is not a prerequisite for dental school in Colombia. To obtain licensure, Colombian dental students must complete 5 years of study in dental school, earn a diploma, and work for the government for 1 year. There are approximately 41,400 dentists in Colombia, and the number is increasing quickly. However, the unemployment rate among dentists is very high, even though graduation from dental school is extremely difficult. Although the 1,100:1 ratio of citizens to dentists is considered satisfactory, access to dental care is limited due to the high rate of poverty. PMID:20339245

  14. Loose-fill insulations

    SciTech Connect

    1995-05-01

    Whether you are increasing the insulation levels in your current home or selecting insulation for a new home, choosing the right insulation material can be challenging. Fibrous loose-fill insulations such as cellulose, fiberglass, and rock wool are options you may wish to consider. This publication will introduce you to these materials--what they are, how they are applied, how they compare with each other, and other considerations regarding their use--so that you can decide whether loose fills are right for your home.

  15. Atypical Forensic Dental Identifications.

    PubMed

    Cardoza, Anthony R; Wood, James D

    2015-06-01

    Forensic dental identification specialists are typically the last conventional option for postmortem identification. Forensic dental identification is most often accomplished by comparing radiographs of the decedent's teeth with the dental radiographs obtained from the dentist of the suspected victim. Unfortunately, antemortem dental radiographs are not always available. When presented with this challenge, the authors of this article have been successful in completing identifications using means other than dental radiographic comparison. PMID:26126345

  16. Atypical Forensic Dental Identifications.

    PubMed

    Cardoza, Anthony R; Wood, James D

    2015-06-01

    Forensic dental identification specialists are typically the last conventional option for postmortem identification. Forensic dental identification is most often accomplished by comparing radiographs of the decedent's teeth with the dental radiographs obtained from the dentist of the suspected victim. Unfortunately, antemortem dental radiographs are not always available. When presented with this challenge, the authors of this article have been successful in completing identifications using means other than dental radiographic comparison.

  17. Income, income inequality, dental caries and dental care levels: an ecological study in rich countries.

    PubMed

    Bernabé, E; Sheiham, A; Sabbah, W

    2009-01-01

    Research has shown that beyond a certain level of absolute income, there is a weak relationship between income and population health. On the other hand, relative income or income inequality is more strongly related to health than absolute income in rich countries. The objective of this study was to assess the relationships of income and income inequality with dental caries and dental care levels in 35- to 44-year-old adults among rich countries. Income was assessed by gross domestic product and gross national income, income inequality by Gini coefficient and the ratio between the income of the richest and poorest 20% of the population, dental caries by DMFT and dental care levels by the care, restorative and treatment indices. Pearson and partial correlation were used to examine the relationships between income, income inequality, caries experience and dental care. Income measures were not related to either dental caries or dental care levels. However, income inequality measures were inversely and significantly related to number of filled teeth, DMFT, care index and restorative index, but not to number of decayed or missing teeth. It is concluded that DMFT scores were higher in more equal countries and may be explained by greater levels of restorative care in those countries.

  18. 2. FOURTH FLOOR VIEW TO NORTHEAST, WITH I.J. STOKES DENTAL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. FOURTH FLOOR VIEW TO NORTHEAST, WITH I.J. STOKES DENTAL POWDER FILLING MACHINE (CENTER) AND PACKING TABLE (LEFT CENTER) - Colgate & Company Jersey City Plant, G Block, 81-95 Greene Street, Jersey City, Hudson County, NJ

  19. Gas filled panel insulation

    DOEpatents

    Griffith, Brent T.; Arasteh, Dariush K.; Selkowitz, Stephen E.

    1993-01-01

    A structural or flexible highly insulative panel which may be translucent, is formed from multi-layer polymeric material in the form of an envelope surrounding a baffle. The baffle is designed so as to minimize heat transfer across the panel, by using material which forms substantially closed spaces to suppress convection of the low conductivity gas fill. At least a portion of the baffle carries a low emissivity surface for suppression of infrared radiation.

  20. Gas filled panel insulation

    DOEpatents

    Griffith, B.T.; Arasteh, D.K.; Selkowitz, S.E.

    1993-12-14

    A structural or flexible highly insulative panel which may be translucent, is formed from multi-layer polymeric material in the form of an envelope surrounding a baffle. The baffle is designed so as to minimize heat transfer across the panel, by using material which forms substantially closed spaces to suppress convection of the low conductivity gas fill. At least a portion of the baffle carries a low emissivity surface for suppression of infrared radiation. 18 figures.

  1. Dental Auxiliary Occupations. Interim Report.

    ERIC Educational Resources Information Center

    Kingston, Richard D.

    As part of a dental auxiliaries project, a Dental Auxiliary National Technical Advisory Committee was established, and its major undertaking was to assist in the development of a functional inventory for each of the three dental auxiliary occupations (dental assisting, dental hygiene, and dental laboratory technology). The analysis consisted of…

  2. Amalgamating eastern Gondwana: The evolution of the Circum-Indian Orogens

    NASA Astrophysics Data System (ADS)

    Collins, Alan S.; Pisarevsky, Sergei A.

    2005-08-01

    The Neoproterozoic global reorganisation that saw the demise of Rodinia and the amalgamation of Gondwana took place during an incredibly dynamic period of Earth evolution. To better understand the palaeogeography of these times, and hence help quantify the interrelations between tectonics and other Earth systems, we here integrate Neoproterozoic palaeomagnetic solutions from the various blocks that made up eastern Gondwana, with the large amount of recent geological data available from the orogenic belts that formed as eastern Gondwana amalgamated. From this study, we have: (1) identified large regions of pre-Neoproterozoic crust within late Neoproterozoic/Cambrian orogenic belts that significantly modify the geometry and number of continental blocks present in the Neoproterozoic world; (2) suggested that one of these blocks, Azania, which consists of Archaean and Palaeoproterozoic crust within the East African Orogen of Madagascar, Somalia, Ethiopia and Arabia, collided with the Congo/Tanzania/Bangweulu Block at ˜ 650-630 Ma to form the East African Orogeny; (3) postulated that India did not amalgamate with any of the Gondwana blocks until the latest Neoproterozoic/Cambrian forming the Kuunga Orogeny between it and Australia/Mawson and coeval orogenesis between India and the previously amalgamated Congo/Tanzania/Bangweulu-Azania Block (we suggest the name 'Malagasy Orogeny' for this event); and, (4) produced a palaeomagnetically and geologically permissive model for Neoproterozoic palaeogeography between 750 and 530 Ma, from the detritus of Rodinia to an amalgamated Gondwana.

  3. Teaching the placement of posterior resin-based composite restorations in Spanish dental schools

    PubMed Central

    Lynch, Christopher; McConnell, Robert; Wilson, Nairn

    2012-01-01

    Objectives: In an area of esthetic dentistry such as posterior composites, in which new materials and techniques are being devolved continuously, it is important to confirm that dental students have a clear understanding of the basic principles of clinical application of this knowledge. Considering that the preparation of dental graduates in Spain may be of interest to competent dental authorities and employers with whom they can work worldwide, this study investigated the teaching of posterior composite restorations in Spanish dental schools. Study design: In late 2009⁄ early 2010, a questionnaire seeking information on the teaching of posterior composites was emailed to the professor responsible for teaching operative dentistry in each of the fifteen dental schools having complete undergraduate dental degree programs in Spain. Results: The response rate was 100%. Most investigated topics did not show noteworthy differences depending on whether the schools were public or private. Variations were found among Spanish dental schools in both the amount and content of the teaching programs concerning posterior composite restorations. Differences were recorded in the teaching of cavity design, contraindications to composite placement, indications for liners and bases, matrix and wedging techniques, composite and bonding systems, light curing and finishing procedures for composite restorations. More consistency was observed in teaching methods of moisture-control, indirect composites and amalgam bonding. Conclusions: As recommended in previously surveyed countries, efforts must be made to promote harmonization of dental curricula to make it easier for graduates to work elsewhere, and to ensure they meet the needs of their patients on entering independent practice. Key words:Aesthetic dentistry, composite restoration, dental education, teaching program, undergraduate dental student. PMID:22322491

  4. Tobacco use and dental disease.

    PubMed

    Hart, G T; Brown, D M; Mincer, H H

    1995-04-01

    The previously cited Indiana University School of Dentistry teaching monograph, "The Impact of Tobacco Use and Cessation on Nonmalignant and Precancerous Oral and Dental Diseases and Conditions," reviewed over 800 articles and concluded that tobacco use is strongly associated with many dental and oral mucosal diseases, and may contribute to others. Our study of a relatively small sample of 200 patients, of whom 33 percent were tobacco users, found statistically significant data correlating tobacco use with a higher Decayed, Missing and Filled Index (a measurement of caries and tooth loss experience of patients) and relating periodontal bone loss to smokeless tobacco use. And, while this investigation did not find a statistically significant correlation between smoking and periodontitis severity, there was a data trend in that direction. Conclusions about tooth loss in the Indiana monograph were limited to smokers; however, there was an association of ST use with gingival recession, which can become quite severe in the area in which the smokeless tobacco is placed. It might be theorized that the significantly larger number of missing teeth among ST users in our study is associated with the generally poor oral hygiene and less sophisticated outlook on health care that tobacco users often display. Indeed, of the 65 denture wearers in our study, 7.7 percent were ST users and 40.0 percent were tobacco users of some type. In view of the large amount of data in the scientific literature associating tobacco with dental diseases as summarized by the Indiana monograph, and the position of several groups such as the American Cancer Society that tobacco is one of the risk factors most associated with intraoral cancer, it would appear that dentists have a vested professional interest in promoting tobacco use cessation among their patients. Dentists should take every reasonable opportunity to persuade patients to discontinue the tobacco habit, thus preventing life

  5. American Dental Education Association

    MedlinePlus

    ... Diversity and Inclusion ADEA Commission on Change and Innovation in Dental Education What is ADEA CCI? ADEA ... Education, 2016–2017 Beyond the Crossroads: Change and Innovation in Dental Education ADEA Guidelines for Ethical Academic ...

  6. Dental x-rays

    MedlinePlus

    X-ray - teeth; Radiograph - dental; Bitewings; Periapical film; Panoramic film; Digital image ... dentist's office. There are many types of dental x-rays. Some of them are: Bitewing. Shows the crown ...

  7. Dental laser technology.

    PubMed

    Fasbinder, Dennis J

    2008-10-01

    Dental technology is rapidly affecting the treatment options available to patients. Dental lasers are an innovative technology for both hard- and soft-tissue treatment applications. The ability to recontour soft tissues efficiently and predictably with immediate hemostatsis and minimal postoperative sequelae is of value to both the dentist and the patient. This article reviews the principles of dental lasers, criteria to consider when selecting a dental laser, and some of their clinical applications.

  8. Replacing Amalgam Restorations: A Standardized Protocol Based on Analyzing Tissue Physicochemical Modifications.

    PubMed

    Decup, Franck; Epaillard, Alexandre; Chemla, Florence

    2015-12-01

    Almost 60% of operative dentistry is devoted to replacing restorations. When practitioners have to replace an amalgam restoration, they tend to opt for an adhesive restoration, as it is conservative of tooth tissues and mimics the natural appearance of teeth. Based on a literature review, the aim of this article is to determine the best tissue approach when replacing an old amalgam by a new adhesive restoration. After analyzing and understanding tissue alterations due to the amalgam corrosion process, the authors propose an analytical approach to managing the situation. Both tissue orientated and specific mechanical approaches are developed and should be implemented to carry out the optimal clinical procedure and achieve the most conservative and durable treatment. PMID:26767237

  9. Accreditation in Dental Hygiene.

    ERIC Educational Resources Information Center

    National Commission on Accrediting, Washington, DC.

    The Council on Dental Education cooperates with the American Dental Hygienists' Association in developing educational requirements for schools of dental hygiene. To be eligible for accreditation, schools must operate on a non-profit basis. A school applying for accreditation completes a previsitation questionnaire concerning its program. The…

  10. Dental records: An overview

    PubMed Central

    Charangowda, B K

    2010-01-01

    Dental records consist of documents related to the history of present illness, clinical examination, diagnosis, treatment done, and the prognosis. A thorough knowledge of dental records is essential for the practicing dentist, as it not only has a forensic application, but also a legal implication with respect to insurance and consumerism. This article reviews the importance of dental records in forensics. PMID:21189983

  11. Dental Manpower Fact Book.

    ERIC Educational Resources Information Center

    Ake, James N.; Johnson, Donald W.

    Statistical data on many aspects of dental and allied dental personnel supply, distribution, characteristics, and education and on certain other aspects of dental services are presented and discussed. The data on dentist supply show the national trend in the supply of active dentists since 1950 and the concurrent changes in dentist-to-population…

  12. Dental Laboratory Technology.

    ERIC Educational Resources Information Center

    Department of the Air Force, Washington, DC.

    The Air Force dental laboratory technology manual is designed as a basic training text as well as a reference source for dental laboratory technicians, a specialty occupation concerned with the design, fabrication, and repair of dental prostheses. Numerous instructive diagrams and photographs are included throughout the manual. The comprehensive…

  13. DENTAL SCHOOL PLANNING.

    ERIC Educational Resources Information Center

    GALAGAN, DONALD J.

    THIS DISCUSSION PRESENTS A COMPLETE PICTURE OF THE CURRENT STATE OF DENTAL EDUCATION WITH SUGGESTIONS FOR MEETING THE DEMANDS FOR DENTAL STAFF AND FACILITIES. THE AREAS INVESTIGATED ARE (1) OBJECTIVES IN DENTAL EDUCATION--COURSES, TEACHING MODES, INNOVATIONS IN CURRICULUM, COORDINATION OF BASIC AND CLINICAL INSTRUCTION, (2) FACILITY…

  14. Dye filled security seal

    DOEpatents

    Wilson, Dennis C. W.

    1982-04-27

    A security seal for providing an indication of unauthorized access to a sealed object includes an elongate member to be entwined in the object such that access is denied unless the member is removed. The elongate member has a hollow, pressurizable chamber extending throughout its length that is filled with a permanent dye under greater than atmospheric pressure. Attempts to cut the member and weld it together are revealed when dye flows through a rupture in the chamber wall and stains the outside surface of the member.

  15. Benchmarking parameter-free AMaLGaM on functions with and without noise.

    PubMed

    Bosman, Peter A N; Grahl, Jörn; Thierens, Dirk

    2013-01-01

    We describe a parameter-free estimation-of-distribution algorithm (EDA) called the adapted maximum-likelihood Gaussian model iterated density-estimation evolutionary algorithm (AMaLGaM-ID[Formula: see text]A, or AMaLGaM for short) for numerical optimization. AMaLGaM is benchmarked within the 2009 black box optimization benchmarking (BBOB) framework and compared to a variant with incremental model building (iAMaLGaM). We study the implications of factorizing the covariance matrix in the Gaussian distribution, to use only a few or no covariances. Further, AMaLGaM and iAMaLGaM are also evaluated on the noisy BBOB problems and we assess how well multiple evaluations per solution can average out noise. Experimental evidence suggests that parameter-free AMaLGaM can solve a wide range of problems efficiently with perceived polynomial scalability, including multimodal problems, obtaining the best or near-best results among all algorithms tested in 2009 on functions such as the step-ellipsoid and Katsuuras, but failing to locate the optimum within the time limit on skew Rastrigin-Bueche separable and Lunacek bi-Rastrigin in higher dimensions. AMaLGaM is found to be more robust to noise than iAMaLGaM due to the larger required population size. Using few or no covariances hinders the EDA from dealing with rotations of the search space. Finally, the use of noise averaging is found to be less efficient than the direct application of the EDA unless the noise is uniformly distributed. AMaLGaM was among the best performing algorithms submitted to the BBOB workshop in 2009.

  16. Fluid Dynamics of Bottle Filling

    NASA Astrophysics Data System (ADS)

    McGough, Patrick; Gao, Haijing; Appathurai, Santosh; Basaran, Osman

    2011-11-01

    Filling of bottles is a widely practiced operation in a large number of industries. Well known examples include filling of ``large'' bottles with shampoos and cleaners in the household products and beauty care industries and filling of ``small'' bottles in the pharmaceutical industry. Some bottle filling operations have recently drawn much attention from the fluid mechanics community because of the occurrence of a multitude of complex flow regimes, transitions, and instabilities such as mounding and coiling that occur as a bottle is filled with a fluid. In this talk, we present a primarily computational study of the fluid dynamical challenges that can arise during the rapid filling of bottles. Given the diversity of fluids used in filling applications, we consider four representative classes of fluids that exhibit Newtonian, shear-thinning, viscoelastic, and yield-stress rheologies. The equations governing the dynamics of bottle filling are solved either in their full 3D but axisymmetric form or using the slender-jet approximation.

  17. Dental school application timing: implications for full admission consideration and improving diversity of dental students.

    PubMed

    Aalboe, Joanna A; Harper, Christine; Beeman, Cynthia S; Paaso, Becky A

    2014-04-01

    The national underrepresentation of minorities in dental schools and the dental profession is a significant concern. Despite efforts over previous years, the number of practicing dentists from underrepresented minority (URM) groups has increased very little. Many dental schools have adopted a holistic admissions review process that uses noncognitive factors in an effort to increase diversity. However, application timing also significantly impacts the success of candidates. This study examined whether URM students' applying late in the application cycle contributes to their lower enrollment. This study attempted to fill a void in the dental admissions knowledge base by examining whether the timing of dental school applications in a rolling admissions system with a set number of interview spots favors those who apply early. De-identified applications (N=1,673) from one U.S. dental school in 2011 were examined. A binary logistic regression analysis revealed that URM applicants were significantly more likely to apply later in the admission cycle than non-URM applicants by a factor of 63 percent (p=0.001), increasing the competiveness for fewer remaining spots. These results suggest the need for pre-admission interventions and for future research to understand and address barriers that impact application timing.

  18. Dental care of autistic children within the non-specialized Public Dental Service.

    PubMed

    Fahlvik-Planefeldt, C; Herrström, P

    2001-01-01

    Children with an autistic disorder may need more dental care and may also be more difficult to treat than healthy children. This study compared oral health in autistic and healthy children. Also explored was the dental management of autistic children within the non-specialized Public Dental Service. The study was designed as a case-control study with all cases of autistic disorders aged 3-19 years identified within a primary care area in southwest Sweden. One dentist did a clinical investigation of cases and one control per case. The patients, or their parents, answered a questionnaire. 28 patients were identified and 20 (71%) agreed to participate in the study. Cases and controls had a similar prevalence of fillings, caries, gingivitis and degree of oral hygiene. However, the need of orthodontic treatment seemed to be greater among the autistic children. According to a standardised assessment, autistic children were less able to cooperate in the dental treatment. Approximately 30% of the cases had occasionally been subjected to specialized dental care. The results of this study indicate that the care provided to autistic children within the non-specialized Public Dental Service is satisfactory, provided that there is access to a paediatric dentist when necessary.

  19. Weaker dental enamel explains dental decay.

    PubMed

    Vieira, Alexandre R; Gibson, Carolyn W; Deeley, Kathleen; Xue, Hui; Li, Yong

    2015-01-01

    Dental caries continues to be the most prevalent bacteria-mediated non-contagious disease of humankind. Dental professionals assert the disease can be explained by poor oral hygiene and a diet rich in sugars but this does not account for caries free individuals exposed to the same risk factors. In order to test the hypothesis that amount of amelogenin during enamel development can influence caries susceptibility, we generated multiple strains of mice with varying levels of available amelogenin during dental development. Mechanical tests showed that dental enamel developed with less amelogenin is "weaker" while the dental enamel of animals over-expressing amelogenin appears to be more resistant to acid dissolution. PMID:25885796

  20. Weaker Dental Enamel Explains Dental Decay

    PubMed Central

    Vieira, Alexandre R.; Gibson, Carolyn W.; Deeley, Kathleen; Xue, Hui; Li, Yong

    2015-01-01

    Dental caries continues to be the most prevalent bacteria-mediated non-contagious disease of humankind. Dental professionals assert the disease can be explained by poor oral hygiene and a diet rich in sugars but this does not account for caries free individuals exposed to the same risk factors. In order to test the hypothesis that amount of amelogenin during enamel development can influence caries susceptibility, we generated multiple strains of mice with varying levels of available amelogenin during dental development. Mechanical tests showed that dental enamel developed with less amelogenin is “weaker” while the dental enamel of animals over-expressing amelogenin appears to be more resistant to acid dissolution. PMID:25885796

  1. Cyclic conjugacy separability and conjugacy separability of certain amalgamated free products

    NASA Astrophysics Data System (ADS)

    Lim, H. M.; Wong, K. B.; Wong, P. C.

    2015-12-01

    In this note, we study cyclic conjugacy separability and conjugacy separability of generalized free products. We first prove the criterions for generalized free products to be cyclic conjugacy separable and conjugacy separable. Our method involved a concept first introduced by G. Baumslag, called filterations. This method makes our criterions clearer and easier for applications. We then extend our criterions to generalized free products of polycyclic-by-finite groups or surface groups amalgamating a central subgroup. Finally, we show that generalized free products of free groups or finitely generated torsion-free nilpotent groups amalgamating an infinite cyclic subgroup are both cyclic conjugacy separable and conjugacy separable.

  2. The combined composite resin and amalgam restoration for posterior teeth: a clinical report.

    PubMed

    Roda, R S; Zwicker, P F

    1992-01-01

    This paper presents a technique for restoring maxillary posterior teeth with a combined composite resin and amalgam restoration when the preparation extends buccally into an esthetically critical area. This technique has two major advantages over traditional combined restorations: it requires only one clinical appointment, and it provides an esthetically acceptable result while maintaining the advantages of an amalgam restoration. A clinical assessment of 12 of these restorations, in vivo for 0.8 to 6.4 years, is presented. All but one restoration received a score of excellent or acceptable.

  3. Artifacts resembling budding bacteria produced in placer-gold amalgams by nitric acid leaching

    USGS Publications Warehouse

    Watterson, J.R.

    1994-01-01

    Microscopic filiform morphologies in gold which are indistinguishable from forms originally interpreted as bacterial in origin were produced in the laboratory by treating amalgams made from natural and artificial gold with hot nitric acid. Textures ranging from cobblestone to deeply crenulated to nodular filiform were produced in the laboratory from all tested natural and artificial gold amalgams; analogous textures widespread in Alaskan placer gold may have a similar inorganic origin. These results indicate that morphology alone cannot be considered adequate evidence of microbial involvement in gold formation. -Author

  4. Artifacts resembling budding bacteria produced in placer-gold amalgams by nitric acid leaching

    USGS Publications Warehouse

    Watterson, J.R.

    1994-01-01

    Microscopic filiform morphologies in gold which are indistinguishable from forms originally interpreted as bacterial in origin were produced in the laboratory by treating amalgams made from natural and artificial gold with hot nitric acid. Textures ranging from cobblestone to deeply crenulated to nodular filiform were produced in the laboratory from all tested natural and artificial gold amalgams; analogous textures widespread in Alaskan placer gold may have a similar inorganic origin. These results indicate that morphology alone cannot be considered adequate evidence of microbial involvement in gold formation.

  5. Hydrogen Filling Station

    SciTech Connect

    Boehm, Robert F; Sabacky, Bruce; Anderson II, Everett B; Haberman, David; Al-Hassin, Mowafak; He, Xiaoming; Morriseau, Brian

    2010-02-24

    future. Project partners also conducted a workshop on hydrogen safety and permitting. This provided an opportunity for the various permitting agencies and end users to gather to share experiences and knowledge. As a result of this workshop, the permitting process for the hydrogen filling station on the Las Vegas Valley Water District’s land was done more efficiently and those who would be responsible for the operation were better educated on the safety and reliability of hydrogen production and storage. The lessons learned in permitting the filling station and conducting this workshop provided a basis for future hydrogen projects in the region. Continuing efforts to increase the working pressure of electrolysis and efficiency have been pursued. Research was also performed on improving the cost, efficiency and durability of Proton Exchange Membrane (PEM) hydrogen technology. Research elements focused upon PEM membranes, electrodes/catalysts, membrane-electrode assemblies, seals, bipolar plates, utilization of renewable power, reliability issues, scale, and advanced conversion topics. Additionally, direct solar-to-hydrogen conversion research to demonstrate stable and efficient photoelectrochemistry (PEC) hydrogen production systems based on a number of optional concepts was performed. Candidate PEC concepts included technical obstacles such as inefficient photocatalysis, inadequate photocurrent due to non-optimal material band gap energies, rapid electron-hole recombination, reduced hole mobility and diminished operational lifetimes of surface materials exposed to electrolytes. Project Objective 1: Design, build, operate hydrogen filling station Project Objective 2: Perform research and development for utilizing solar technologies on the hydrogen filling station and convert two utility vehicles for use by the station operators Project Objective 3: Increase capacity of hydrogen filling station; add additional vehicle; conduct safety workshop; develop a roadmap for

  6. The pregnant dental patient.

    PubMed

    Singh, Medha

    2012-01-01

    When dealing with a pregnant patient, the dental practitioner should keep in mind the various physiological changes that occur in the pregnant female and the potential effects on the fetus in using various types of local anesthesia. This article reviews the current considerations in the use of local anesthesia in the pregnant dental patient, and the safety of local anesthetics, their dosage, and any adverse effect on mother and fetus. It also discusses various dental procedures and the trimester during which they can be performed. Lastly, this article talks about the complications that can occur with a pregnant dental patient in the dental chair.

  7. Practitioner, patient, and caries lesion characteristics associated with type of material used to restore carious teeth: findings from The Dental PBRN

    PubMed Central

    Makhija, Sonia K; Gordan, Valeria V.; Gilbert, Gregg H.; Litaker, Mark S.; Rindal, D. Brad; Pihlstrom, Daniel J.; Qvist, Vibeke

    2011-01-01

    Background The authors conducted a study to identify factors associated with material use by dentists in The Dental Practice-Based Research Network (DPBRN) when placing the first restoration on permanent tooth surfaces. Methods A total of 182 DPBRN practitioner-investigators provided data on 5,599 posterior teeth with caries. Practitioner-investigators completed an enrollment questionnaire that included the dentist’s age, gender, practice workload, practice type, and years since graduation. When a consented patient presented with a previously un-restored carious surface, practitioner-investigators recorded patient and tooth characteristics. Results Amalgam was used more often than direct resin-based composite (RBC) for posterior carious lesions. Practitioner/practice characteristics (years since graduation and type of practice); patient characteristics (gender, race, age, and dental insurance); and lesion characteristics (tooth location and surface, pre-and post-operative depth) were associated with the type of restorative material used. Conclusions There are several practitioner/practice, patient, and lesion characteristics significantly associated with use of amalgam and RBC: region, years since graduation, dental insurance, tooth location and surface, and pre-and post-operative depth. Clinical implications Amalgam remains a material commonly used by United States dentists to restore posterior caries lesions. PMID:21628683

  8. Bulk-fill resin composites: polymerization contraction, depth of cure, and gap formation.

    PubMed

    Benetti, A R; Havndrup-Pedersen, C; Honoré, D; Pedersen, M K; Pallesen, U

    2015-01-01

    The bulk-filling of deep, wide dental cavities is faster and easier than traditional incremental restoration. However, the extent of cure at the bottom of the restoration should be carefully examined in combination with the polymerization contraction and gap formation that occur during the restorative procedure. The aim of this study, therefore, was to compare the depth of cure, polymerization contraction, and gap formation in bulk-fill resin composites with those of a conventional resin composite. To achieve this, the depth of cure was assessed in accordance with the International Organization for Standardization 4049 standard, and the polymerization contraction was determined using the bonded-disc method. The gap formation was measured at the dentin margin of Class II cavities. Five bulk-fill resin composites were investigated: two high-viscosity (Tetric EvoCeram Bulk Fill, SonicFill) and three low-viscosity (x-tra base, Venus Bulk Fill, SDR) materials. Compared with the conventional resin composite, the high-viscosity bulk-fill materials exhibited only a small increase (but significant for Tetric EvoCeram Bulk Fill) in depth of cure and polymerization contraction, whereas the low-viscosity bulk-fill materials produced a significantly larger depth of cure and polymerization contraction. Although most of the bulk-fill materials exhibited a gap formation similar to that of the conventional resin composite, two of the low-viscosity bulk-fill resin composites, x-tra base and Venus Bulk Fill, produced larger gaps.

  9. Description and Documentation of the Dental School Dental Delivery System.

    ERIC Educational Resources Information Center

    Chase, Rosen and Wallace, Inc., Alexandria, VA.

    A study was undertaken to describe and document the dental school dental delivery system using an integrated systems approach. In late 1976 and early 1977, a team of systems analysts and dental consultants visited three dental schools to observe the delivery of dental services and patient flow and to interview administrative staff and faculty.…

  10. [In vitro comparison of marginal adaptation of various filling materials. I. Effect of the filling material on marginal adaptation].

    PubMed

    Kóhalmi, T; Gorzo, I; Mari, A; Nagy, K

    1999-03-01

    In a two-month in vitro experiment cervical marginal adaptation was examined in relation to the preparation, filling method and restorative material. Fifty Class II cavities were prepared in fifty extracted sound human premolar and molar teeth extending to the approximal cement-enamel junction. The cavities to receive composite restorations were bevelled at the vestibulo-occlusal and -approximal enamel margins, the other aspects of the cavity enamel and gingival margins at the cement-enamel junction being prepared conventionally. The cavities for amalgam were prepared and filled conventionally. The specimens were cycled in different buffer solutions and temperature, modelling possible variations in the oral environment and examined with SEM. The results were analysed using ANOVA. The best marginal adaptation among the composites was achieved with Charisma, Estilux Posterior, Durafil and Prisma AP. H at the bevelled enamel margins, the worst marginal fit was with Heliomolar and Polofil. It was concluded, that adhesive technique reduces, but does not eliminate marginal leakage. PMID:10205985

  11. Identification through X-ray fluorescence analysis of dental restorative resin materials: a comprehensive study of noncremated, cremated, and processed-cremated individuals.

    PubMed

    Bush, Mary A; Miller, Raymond G; Prutsman-Pfeiffer, Jennifer; Bush, Peter J

    2007-01-01

    Tooth-colored restorative materials are increasingly being placed in the practice of modern dentistry, replacing traditional materials such as amalgam. Many restorative resins have distinct elemental compositions that allow identification of brand. Not only are resins classifiable by elemental content, but they also survive extreme conditions such as cremation. This is of significance to the forensic odontologist because resin uniqueness adds another level of certainty in victim identification, especially when traditional means are exhausted. In this three-part study, unique combinations of resins were placed in six human cadavers (total 70 restorations). Simulated ante-mortem dental records were created. In a blind experiment, a portable X-ray fluorescence (XRF) unit was used to locate and identify the resin brands placed in the dentition. The technique was successful in location and brand identification of 53 of the restorations, which was sufficient to enable positive victim identification among the study group. This part of the experiment demonstrated the utility of portable XRF in detection and analysis of restorative materials for victim identification in field or morgue settings. Identification of individuals after cremation is a more difficult task, as the dentition is altered by shrinkage and fragmentation, and may not be comparable with a dental chart. Identification of processed cremains is a much greater challenge, as comminution obliterates all structural relationships. Under both circumstances, it is the nonbiological artifacts that aid in identification. Restorative resin fillings can survive these conditions, and can still be named by brand utilizing elemental analysis. In a continuation of the study, the cadavers were cremated in a cremation retort under standard mortuary conditions. XRF was again used to analyze retrieved resins and to identify the individuals based on restorative materials known to exist from dental records. The cremains were

  12. Identification through X-ray fluorescence analysis of dental restorative resin materials: a comprehensive study of noncremated, cremated, and processed-cremated individuals.

    PubMed

    Bush, Mary A; Miller, Raymond G; Prutsman-Pfeiffer, Jennifer; Bush, Peter J

    2007-01-01

    Tooth-colored restorative materials are increasingly being placed in the practice of modern dentistry, replacing traditional materials such as amalgam. Many restorative resins have distinct elemental compositions that allow identification of brand. Not only are resins classifiable by elemental content, but they also survive extreme conditions such as cremation. This is of significance to the forensic odontologist because resin uniqueness adds another level of certainty in victim identification, especially when traditional means are exhausted. In this three-part study, unique combinations of resins were placed in six human cadavers (total 70 restorations). Simulated ante-mortem dental records were created. In a blind experiment, a portable X-ray fluorescence (XRF) unit was used to locate and identify the resin brands placed in the dentition. The technique was successful in location and brand identification of 53 of the restorations, which was sufficient to enable positive victim identification among the study group. This part of the experiment demonstrated the utility of portable XRF in detection and analysis of restorative materials for victim identification in field or morgue settings. Identification of individuals after cremation is a more difficult task, as the dentition is altered by shrinkage and fragmentation, and may not be comparable with a dental chart. Identification of processed cremains is a much greater challenge, as comminution obliterates all structural relationships. Under both circumstances, it is the nonbiological artifacts that aid in identification. Restorative resin fillings can survive these conditions, and can still be named by brand utilizing elemental analysis. In a continuation of the study, the cadavers were cremated in a cremation retort under standard mortuary conditions. XRF was again used to analyze retrieved resins and to identify the individuals based on restorative materials known to exist from dental records. The cremains were

  13. Genetic polymorphisms affecting susceptibility to mercury neurotoxicity in children: summary findings from the Casa Pia Children's Amalgam clinical trial.

    PubMed

    Woods, James S; Heyer, Nicholas J; Russo, Joan E; Martin, Michael D; Farin, Federico M

    2014-09-01

    Mercury (Hg) is neurotoxic, and children may be particularly susceptible to this effect. A current major challenge is identification of children who may be uniquely susceptible to Hg toxicity because of genetic predisposition. We examined the possibility that common genetic variants that are known to affect neurologic functions or Hg handling in adults would modify the adverse neurobehavioral effects of Hg exposure in children. Three hundred thirty subjects who participated as children in the recently completed Casa Pia Clinical Trial of Dental Amalgams in Children were genotyped for 27 variants of 13 genes that are reported to affect neurologic functions and/or Hg disposition in adults. Urinary Hg concentrations, reflecting Hg exposure from any source, served as the Hg exposure index. Regression modeling strategies were employed to evaluate potential associations between allelic status for individual genes or combinations of genes, Hg exposure, and neurobehavioral test outcomes assessed at baseline and for 7 subsequent years during the clinical trial. Among boys, significant modification of Hg effects on neurobehavioral outcomes over a broad range of neurologic domains was observed with variant genotypes for 4 of 13 genes evaluated. Modification of Hg effects on a more limited number of neurobehavioral outcomes was also observed for variants of another 8 genes. Cluster analyses suggested some genes interacting in common processes to affect Hg neurotoxicity. In contrast, significant modification of Hg effects on neurobehavioral functions among girls with the same genotypes was substantially more limited. These observations suggest increased susceptibility to the adverse neurobehavioral effects of Hg among children, particularly boys, with genetic variants that are relatively common to the general human population. These findings advance public health goals to identify factors underlying susceptibility to Hg toxicity and may contribute to strategies for preventing

  14. A survey of magnetic fields in the dental operatory.

    PubMed

    Bohay, R N; Bencak, J; Kavaliers, M; Maclean, D

    1994-09-01

    Recently, there has been growing concern regarding the biological effects of occupational exposure to weak time-varying magnetic fields, especially those in the extremely low-frequency range (0.1-100.0 Hz). This study examined some potential sources and intensities of 60 Hz magnetic fields produced in the dental environment. A random sample of general dental offices and selected specialty offices was visited, and the magnetic fields associated with ultrasonic scalers, amalgamators, composite light curing units, X-ray view boxes and chair lights were measured. The median 60 Hz field strengths measured at various running speeds (off, standby, low and high) and the distances from the equipment (0, 15 and 30 cm) ranged from 1.2 to 2,225 milligauss (mG). Field strengths fell off quickly with distance, but were less affected by the running speed of the equipment. They also varied among the five types of equipment tested. This was likely due to variations in the make, model and age of the equipment. The 60 Hz magnetic field strengths recorded in the dental operatory were comparable to those reported from measurements of common household appliances. However, in view of recent concerns with respect to the possible effects of magnetic fields, it is suggested that exposures be minimized and the concept of prudent avoidance be employed.

  15. Mold filling of titanium alloys in two different wedge-shaped molds.

    PubMed

    Shimizu, H; Habu, T; Takada, Y; Watanabe, K; Okuno, O; Okabe, T

    2002-06-01

    Pure titanium and titanium alloys are potential materials for the fabrication of cast dental appliances. One important factor in producing sound castings is the capacity of the metal to fill the mold. This study used a wedge-shaped mold to compare the mold filling of titanium with that of conventional dental casting alloys. The metals used were CP Ti, Ti-6Al-7Nb, Ti-6Al-4V, Ti with 1 and 4wt% Cu and ADA Type III gold alloy and an Ni-Cr alloy. The castings were cut into four pieces parallel to the triangular surface. Mold filling was evaluated as the distance between the tip of the cast wedge and theoretical tip of the triangle. The mold filling of the gold alloy was superior compared to all the metals tested, while the mold filling of the Ni-Cr alloy was the worst. There were no statistical differences at the 30 degrees marginal angle for all the cast titanium metals. At the sharper 15 degrees angle, CP Ti and Ti-6Al-7Nb was superior to both the Ti-Cu alloys. Although the mold filling of titanium was inferior compared to the gold alloy, the data justify the use of titanium for the production of dental appliances.

  16. The Future of Dental Education.

    ERIC Educational Resources Information Center

    Simonsen, Richard J.

    1994-01-01

    The author, a representative of the American Dental Trade Association, identifies major challenges facing dental education in the areas of predoctoral dental education, postdoctoral dental education, and continuing dental education. Ten recommendations address preclinical and clinical courses, licensing examinations, mandatory continuing…

  17. Amalgam Surface Treatment by Different Output Powers of Er:YAG Laser:SEM Evaluation

    PubMed Central

    Hosseini, Mohammad Hashem; Hassanpour, Mehdi; Etemadi, Ardavan; Ranjbar Omrani, Ladan; Darvishpour, Hojat; Chiniforush, Nasim

    2015-01-01

    Introduction: The purpose of this study was to evaluate amalgam surfaces treated by different output powers of erbium-doped yttrium aluminum garnet (Er:YAG) laser by scanning electron microscope (SEM). Methods: Twenty-one amalgam blocks (8 mm × 8 mm, 3 mm thickness) were prepared by condensing silver amalgam (into putty impression material. After keeping them for 24 hours in distilled water, they were divided into 7 groups as follow: G1: Er:YAG laser (1 W, 50 mJ), G2: Er:YAG laser (2 W, 100 mJ), G3: Er:YAG laser (3 W, 150 mJ), G4: Sandblast, G5: Sandblast + Er:YAG laser (1 W, 50 mJ), G6: Sandblast +Er:YAG laser (2 W, 100 mJ) and G7: Sandblast +Er:YAG laser (3 W, 150 mJ). Then after preparation of all samples, they were examined by SEM. Results: The SEM results of amalgam surfaces treated by different output powers of Er:YAG laser showed some pitting areas with non-homogenous irregularities Conclusion: It seems that the application of sandblasting accompanied by Er:YAG laser irradiation can provide proper surface for bonding of orthodontic brackets. PMID:26705463

  18. When Old and New Regionalism Collide: Deinstitutionalization of Regions and Resistance Identity in Municipality Amalgamations

    ERIC Educational Resources Information Center

    Zimmerbauer, Kaj; Paasi, Anssi

    2013-01-01

    Regions as well as their identities and borders are social and discursive constructs that are produced and removed in contested, historically contingent and context-bound processes of institutionalization and deinstitutionalization. This article studies the deinstitutionalization of regions in the context of municipality amalgamations and the…

  19. 75 FR 10331 - In the Matter of: Amalgamated Explorations, Inc., Areawide Cellular, Inc., Genomed, Inc., Global...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-05

    ... From the Federal Register Online via the Government Publishing Office SECURITIES AND EXCHANGE COMMISSION In the Matter of: Amalgamated Explorations, Inc., Areawide Cellular, Inc., Genomed, Inc., Global Maintech Corp., Military Resale Group, Inc., Verado Holdings, Inc., and World Transport Authority, Inc.; Order of Suspension of Trading It...

  20. Fracture resistance of teeth with Class II bonded amalgam and new tooth-colored restorations.

    PubMed

    Görücü, Jale; Ozgünaltay, Gül

    2003-01-01

    This study compared the cuspal fracture resistance of posterior teeth restored with four different adhesive restorations. Fifty sound, maxillary human premolars were randomly divided into a control group and four experimental groups with 10 teeth in each. Specimens in the first group were intact teeth that were tested as unprepared. The remaining four groups received mesio-oclusodistal cavity preparations and were restored with a hybrid composite (Filtek Z250), a packable composite (Filtek P60), an ormocer (Definite) and an amalgam (SDI Permite) with an amalgam bonding agent (Amalgam Bond Plus). All groups were stored in water at 37 degrees C for 15 days and thermocycled 1000 times between 5 degrees-55 degrees C. The specimens were preloaded five times in compression to 10 kg using two metal rods that contacted only the teeth on the cuspal inclines. The teeth were then loaded occlusally in an Instron Universal Testing Machine until fracture occurred. The means of force required to fracture the teeth in each of the five groups was analyzed using one-way ANOVA and Tukey Test. The difference between the mean cuspal fracture resistance of the unprepared control teeth and those restored with amalgam groups was found to be statistically significant (p < 0.05). No significant differences in resistance to cuspal fracture were found among the restoration groups, the unprepared control group and those teeth restored with hybrid composite, packable composite and ormocer groups (p > 0.05).

  1. Colorimetric Signal Amplification Assay for Mercury Ions Based on the Catalysis of Gold Amalgam.

    PubMed

    Chen, Zhengbo; Zhang, Chenmeng; Gao, Qinggang; Wang, Guo; Tan, Lulu; Liao, Qing

    2015-11-01

    Mercury is a major threat to the environment and to human health. It is highly desirable to develop a user-friendly kit for on-site mercury detection. Such a method must be able to detect mercury below the threshold levels (10 nM) for drinking water defined by the U.S. Environmental Protection Agency. Herein, we for the first time reported catalytically active gold amalgam-based reaction between 4-nitrophenol and NaBH4 with colorimetric sensing function. We take advantage of the correlation between the catalytic properties and the surface area of gold amalgam, which is proportional to the amount of the gold nanoparticle (AuNP)-bound Hg(2+). As the concentration of Hg(2+) increases until the saturation of Hg onto the AuNPs, the catalytic performance of the gold amalgam is much stronger due to the formation of gold amalgam and the increase of the nanoparticle surface area, leading to the decrease of the reduction time of 4-nitrophenol for the color change. This sensing system exhibits excellent selectivity and ultrahigh sensitivity up to the 1.45 nM detection limit. The practical use of this system for Hg(2+) determination in tap water samples is also demonstrated successfully.

  2. Fostering Constructivist Communities of Learners in the Amalgamated Multi-Discipline of Social Studies

    ERIC Educational Resources Information Center

    Mintrop, Heinrich

    2004-01-01

    This paper shows how the knowledge structures and traditions of the amalgamated multi-discipline of social studies at once help and hinder the use of constructivist instructional models. I interpret the planning process of two "Fostering a Community of Learners" units and examine how these two units are implemented by four teachers, given their…

  3. Electrolytic method for the production of lithium using a lithium-amalgam electrode

    DOEpatents

    Cooper, John F.; Krikorian, Oscar H.; Homsy, Robert V.

    1979-01-01

    A method for recovering lithium from its molten amalgam by electrolysis of the amalgam in an electrolytic cell containing as a molten electrolyte a fused-salt consisting essentially of a mixture of two or more alkali metal halides, preferably alkali metal halides selected from lithium iodide, lithium chloride, potassium iodide and potassium chloride. A particularly suitable molten electrolyte is a fused-salt consisting essentially of a mixture of at least three components obtained by modifying an eutectic mixture of LiI-KI by the addition of a minor amount of one or more alkali metal halides. The lithium-amalgam fused-salt cell may be used in an electrolytic system for recovering lithium from an aqueous solution of a lithium compound, wherein electrolysis of the aqueous solution in an aqueous cell in the presence of a mercury cathode produces a lithium amalgam. The present method is particularly useful for the regeneration of lithium from the aqueous reaction products of a lithium-water-air battery.

  4. Treatment of amalgam tattoo with an Er,Cr:YSGG laser.

    PubMed

    Yilmaz, Hasan Guney; Bayindir, Hakan; Kusakci-Seker, Basak; Tasar, Simge; Kurtulmus-Yilmaz, Sevcan

    2010-08-01

    Amalgam tattoos are common, asymptomatic, pigmented oral lesions that clinically exist as isolated, blue, gray, or black macules on the gingival, buccal, and alveolar mucosae, the palate, and/or the tongue. In this case report, the successful use of an erbium, chromium-doped:yttrium, scandium, gallium, and garnet laser for the removal of an amalgam tattoo is explained. A 46-year-old man is presented with a half decade history of an amalgam tattoo on his left maxillary premolar-molar gingiva. Depigmentation procedure was performed under topical anesthesia with the use of an erbium, chromium-doped:yttrium, scandium, gallium, and garnet laser at 2 W in the soft tissue pulsed mode for 10 min. The pigmented tissue was completely removed. The de-epithelialization area healed completely on the 10th day after treatment. The period of healing was uneventful. The amalgam tattoo was completely removed with erbium, chromium-doped:yttrium, scandium, gallium, and garnet laser, and the treated area healed without any adverse effect. PMID:25427187

  5. Real-Time Plasmonic Monitoring of Single Gold Amalgam Nanoalloy Electrochemical Formation and Stripping.

    PubMed

    Wang, Jun-Gang; Fossey, John S; Li, Meng; Xie, Tao; Long, Yi-Tao

    2016-03-01

    Direct electrodeposition of mercury onto gold nanorods on an ITO substrate, without reducing agents, is reported. The growth of single gold amalgam nanoalloy particles and subsequent stripping was monitored in real-time monitoring by plasmonic effects and single-nanoparticle dark-field spectroelectrochemistry techniques. Time-dependent scattering spectral information conferred insight into the growth and stripping mechanism of a single nanoalloy particle. Four critical stages were observed: First, rapid deposition of Hg atoms onto Au nanorods; second, slow diffusion of Hg atoms into Au nanorods; third, prompt stripping of Hg atoms from Au nanorods; fourth, moderate diffusion from the inner core of Au nanorods. Under high Hg(2+) concentrations, homogeneous spherical gold amalgam nanoalloys were obtained. These results demonstrate that the morphology and composition of individual gold amalgam nanoalloys can be precisely regulated electrochemically. Moreover, gold amalgam nanoalloys with intriguing optical properties, such as modulated plasmonic lifetimes and quality factor Q, could be obtained. This may offer opportunities to extend applications in photovoltaic energy conversion and chemical sensing. PMID:26942394

  6. What is dental ecology?

    PubMed

    Cuozzo, Frank P; Sauther, Michelle L

    2012-06-01

    Teeth have long been used as indicators of primate ecology. Early work focused on the links between dental morphology, diet, and behavior, with more recent years emphasizing dental wear, microstructure, development, and biogeochemistry, to understand primate ecology. Our study of Lemur catta at the Beza Mahafaly Special Reserve, Madagascar, has revealed an unusual pattern of severe tooth wear and frequent tooth loss, primarily the result of consuming a fallback food for which these primates are not dentally adapted. Interpreting these data was only possible by combining our areas of expertise (dental anatomy [FC] and primate ecology [MS]). By integrating theoretical, methodological, and applied aspects of both areas of research, we adopted the term "dental ecology"-defined as the broad study of how teeth respond to the environment. Specifically, we view dental ecology as an interpretive framework using teeth as a vehicle for understanding an organism's ecology, which builds upon earlier work, but creates a new synthesis of anatomy and ecology that is only possible with detailed knowledge of living primates. This framework includes (1) identifying patterns of dental pathology and tooth use-wear, within the context of feeding ecology, behavior, habitat variation, and anthropogenic change, (2) assessing ways in which dental development and biogeochemical signals can reflect habitat, environmental change and/or stress, and (3) how dental microstructure and macro-morphology are adapted to, and reflect feeding ecology. Here we define dental ecology, provide a short summary of the development of this perspective, and place our new work into this context.

  7. Marketing the dental hygienist as a manager in oral health care settings.

    PubMed

    Thomson, E M

    1989-09-01

    In 1985, the ADHA, in response to the changing health care environment, identified six roles for the future of dental hygiene. The administrator/manager role, one of the six, is an expansion of dental hygiene skills to facilitate the provision of quality oral health care. Oral health care settings require personnel trained in management to accomplish practice-related goals and objectives. Dental hygiene is preparing individuals to assume managerial roles to fill this health care need. This paper discusses the skills and knowledge level required to assume managerial roles and strategies for marketing the dental hygienist as a manager.

  8. Dental hygiene in Slovakia.

    PubMed

    Luciak-Donsberger, C; Krizanová, M

    2004-08-01

    This article reports on the development of the dental hygiene profession in Slovakia from a global perspective. The aim is to inform about current developments and to examine, how access to qualified dental hygiene care might be improved and how professional challenges might be met. For an international study on dental hygiene, secondary source data were obtained from members of the House of Delegates of the International Federation of Dental Hygienists (IFDH) or by fax and e-mail from experts involved in the national professional and educational organization of dental hygiene in non-IFDH member countries, such as Slovakia. Responses were followed-up by interviews, e-mail correspondence, visits to international universities, and a review of supporting studies and reference literature. Results show that the introduction of dental hygiene in Slovakia in 1992 was inspired by the delivery of preventive care in Switzerland. Initiating local dentists and dental hygienists strive to attain a high educational level, equitable to that of countries in which dental hygiene has an established tradition of high quality care. Low access to qualified dental hygiene care may be a result of insufficient funding for preventive services, social and cultural lack of awareness of the benefits of preventive care, and of limitations inherent in the legal constraints preventing unsupervised dental hygiene practice. These may be a result of gender politics affecting a female-dominated profession and of a perception that dental hygiene is auxiliary to dental care. International comparison show that of all Eastern European countries, the dental hygiene profession appears most advanced in Slovakia. This is expressed in high evidence-based academic goals, in extensive work with international consultants from the Netherlands and Switzerland, in annual congresses of high professional quality, and in the establishment of a profession, which has not been introduced in all Western EU countries

  9. Veneers

    MedlinePlus

    ... Risk for Early Childhood Tooth Decay? What is Dental Amalgam (Silver Filling)? How Do I Care for My Child's Baby Teeth? What is Orofacial Pain? Pacifiers Have Negative and Positive Effects Learn what ...

  10. Clinical Success Rate of Compomer and Amalgam Class II Restorations in First Primary Molars: A Two-year Study

    PubMed Central

    Ghaderi, Faezeh; Mardani, Ali

    2015-01-01

    Background and aims. The majority of failures in Class II amalgam restorations occur in the first primary molar teeth; in addition, use of compomer instead of amalgam for primary molar teeth restorations is a matter of concern. The aim ofthe present study was to compare the success rate of Class II compomer and amalgam restorations in the first primary molars. Materials and methods. A total of 17 amalgams and 17 compomer restorations were placed in 17 children based on a split-mouth design. Restorations were assessed at 12- and 24-month intervals for marginal integrity, the anatomic form and recurrent caries. Data were analyzed with SPSS 11. Chi-squared test was applied for the analysis. Statistical significance was set at P<0.05. Results. A total 34 restorations of 28 restorations (14 pairs) of the total restorations still survived after 24 months. Compomerrestorations showed significantly better results in marginal integrity. Recurrent caries was significantly lower incompomer restorations compared to amalgam restorations. Cumulative success rate at 24-month interval was significantlyhigher in compomer restorations compared to amalgam restorations. There was no statistically significant difference inanatomic form between the two materials. Conclusion. Compomer appears to be a suitable alternative to amalgam for Class II restorations in the first primary mo-lars. PMID:26236434

  11. Meeting Dental Health Needs Through Dental Education

    ERIC Educational Resources Information Center

    Morris, Alvin L.

    1972-01-01

    Dental health needs of the country cannot be met through education of more dentists. Rather, we must educate auxiliaries to perform many of the intraoral procedures now regarded the sole responsibility of dentists. (SB)

  12. Employment of Dental Hygienists as Dental Educators.

    ERIC Educational Resources Information Center

    Fong, Cynthia; Odrich, Johanna

    1987-01-01

    A study of the use of dental hygienists to teach periodontics, preventive dentistry, community dentistry, and public health courses looked at employment patterns and practices and the qualifications of the teachers. (MSE)

  13. Changes of the dental service delivered to patients with intellectual disability under general anaesthesia in Dental Polyclinic Split, Croatia, during the years 1985-2009.

    PubMed

    Kovacić, Ivan; Tadin, Antonija; Petricević, Nikola; Mikelić, Branimira; Vidović, Neven; Palac, Antonija; Filipović-Zore, Irina; Celebić, Asja

    2012-09-01

    People with intellectual disability (ID) usually have a poor quality of oral health, which include poor oral hygiene, untreated caries and high proportion of missing teeth. Due to their fear and repulsive attitude towards medical staff general anesthesia is often a useful method for dental treatment. One thousand and fifty four intellectual disability patients for the period of 1985-2009 who received dental treatment under general anesthesia in Dental Polyclinic Split, were included in the study. Patients were divided into five groups based upon the period when a specific dental treatment had been received. Each period was analyzed for the number of ID patients treated and the type of dental treatment. The results showed that the most services provided were 4006 fillings, followed by 3225 extracted teeth and finally 274 endodontic treatments. Significantly the lowest number of fillings and endodontic treatments were found among patients in group II (1990-1994), with significantly the highest number of extracted teeth. In Conclusion, the types of dental treatment have changed during twenty five years. Number of extracted teeth decreased while the number of fillings and endodontic treatment increased. However, dental status of people with intellectual disability should be improved with more restorative treatments and with better oral health prevention program.

  14. Case based dental radiology.

    PubMed

    Niemiec, Brook A

    2009-02-01

    Dental radiology is quickly becoming integral to the standard of care in veterinary dentistry. This is not only because it is critical for proper patient care, but also because client expectations have increased. Furthermore, providing dental radiographs as a routine service can create significant practice income. This article details numerous conditions that are indications for dental radiographs. As you will see, dental radiographs are often critical for proper diagnosis and treatment. These conditions should not be viewed as unusual; they are present within all of our practices. When you choose not to radiograph these teeth, you leave behind painful pathology. Utilizing the knowledge gained from dental radiographs will both improve patient care and increase acceptance of treatment recommendations. Consequently, this leads to increased numbers of dental procedures performed at your practice. PMID:19410233

  15. Dental education and dentistry system in Iran.

    PubMed

    Pakshir, Hamid Reza

    2003-01-01

    Before 1979, there were only 5 undergraduate dental schools in Iran with a total admission of 200 students per year, and only 2,000 dentists and about 50 specialists practicing in the country. Currently, there are 18 dental schools with a total admission of 750 undergraduate students, 5 postgraduate programs in 10 disciplines with a total of 100 students, more than 11,000 dentists (1 dentist per 5,500 population) and nearly 1,000 specialists in the country. Two new schools have recently begun offering specialty training courses in 2 disciplines. The length of the dentistry curriculum is 6 years. Students take general and basic science courses during the first 2 years, then continue on the predental and dental courses for the remaining 4 years. The curriculum has been revised over the past 20 years to establish intership and specialty programs and introduce courses reflecting current trends in the dental profession. Dental services in Iran are provided by both public and private sectors. Oral health care was integrated into the Public Health Care network by 1997, and 4 levels of a Dental Health Care Delivery System were established. The first level is concerned with primary prevention at 'health houses', where auxiliary health workers called 'behvarzes' provide periodic examinations, referrals, and oral health education. At the next level, oral hygienists and dentists in 'health centers' perform basic oral health care services such as fillings, scaling, and extraction. At the third level, dentists manage and treat oral diseases in 'urban health centers', while the last level is for advanced treatment by specialists in university health centers in the cities.

  16. [Determination of dental age].

    PubMed

    Willems, Guy

    2005-01-01

    A review of the most commonly used dental age estimating techniques is generated. The most important issue for the forensic odontologist involved in dental age estimation is to employ as many of these methods as possible by performing repetitive measurements and calculations of different age-related parameters. That is the only way in order to try and establish reliable dental age estimations. In particular, a special chapter is attributed to the complex problem of determining the age of majority. PMID:16370435

  17. Dental Implant Systems

    PubMed Central

    Oshida, Yoshiki; Tuna, Elif B.; Aktören, Oya; Gençay, Koray

    2010-01-01

    Among various dental materials and their successful applications, a dental implant is a good example of the integrated system of science and technology involved in multiple disciplines including surface chemistry and physics, biomechanics, from macro-scale to nano-scale manufacturing technologies and surface engineering. As many other dental materials and devices, there are crucial requirements taken upon on dental implants systems, since surface of dental implants is directly in contact with vital hard/soft tissue and is subjected to chemical as well as mechanical bio-environments. Such requirements should, at least, include biological compatibility, mechanical compatibility, and morphological compatibility to surrounding vital tissues. In this review, based on carefully selected about 500 published articles, these requirements plus MRI compatibility are firstly reviewed, followed by surface texturing methods in details. Normally dental implants are placed to lost tooth/teeth location(s) in adult patients whose skeleton and bony growth have already completed. However, there are some controversial issues for placing dental implants in growing patients. This point has been, in most of dental articles, overlooked. This review, therefore, throws a deliberate sight on this point. Concluding this review, we are proposing a novel implant system that integrates materials science and up-dated surface technology to improve dental implant systems exhibiting bio- and mechano-functionalities. PMID:20480036

  18. Taekwondo coaches knowledge about prevention and management of dental trauma.

    PubMed

    Vidović, Dina; Gorseta, Kristina; Bursac, Danijel; Glavina, Domagoj; Skrinjarić, Tomislav

    2014-06-01

    The aim of this study was to assess level of knowledge about prevention and dental trauma management among taekwondo coaches in Croatia. The questionnaire submitted to the taekwondo coaches contained 16 items about dental trauma prevention and management. The questionnaires were filled in by 131 taekwondo coaches; 28 females and 103 males. Descriptive statistics was used to describe and analyze the obtained data. The coaches were familiar with dental injuries in high percentage: 41 (31.3%) have observed dental injury and 36 (27.5%) have experienced a dental injury themselves. Eight of them had tooth avulsion, fourteen crown fracture, and eight had tooth luxation. About half of all interviewed coaches 68 (52.7%) were aware of the possibility of replanting avulsed teeth. Twenty six (19.8%) were familiar with the tooth rescue kit. Only 99 out of 131 coaches (75.6%) have used a mouthguard. The obtained results show low knowledge about possibilities for prevention of dental trauma. Insufficient use of mouthguards in this contact sport requires more attention of dentists and coaches education about dental trauma prevention.

  19. Respiratory morbidity in a population of French dental technicians

    PubMed Central

    Radi, S; Dalphin, J; Manzoni, P; Pernet, D; Leboube, M; Viel, J

    2002-01-01

    Aims: To compare wage earner dental technicians with non-exposed salaried subjects for the prevalence of respiratory symptoms and function, and chest x ray abnormalities. Methods: A total of 134 dental technicians and 131 non-exposed subjects participated. A medical and an occupational questionnaire were filled in to evaluate the prevalence of respiratory symptoms and occupational exposures. Subjects underwent respiratory tests and chest x ray examination. Results: Mean age of the dental technicians was 36.6 years with a mean duration of dental work of 16.5 years. There was a significant risk of cough (day and night) and usual phlegm in dental technicians. Respiratory function parameters were lower in dental technicians with a significant difference between exposed and non-exposed groups for % FVC (forced vital capacity), % FEF25 (forced mid expiratory flow), and % FEF50. The prevalence of small opacities increased with age. Small opacities were significantly related to an exposure to asbestos in the past. Conclusions: Our young population of dental technicians is at risk of respiratory morbidity. They should benefit from adequate technical prevention measures. PMID:12040116

  20. Comparison of Dental Explorers and CPI-probes in Diagnosing Dental Caries.

    PubMed

    Ishizuka, Yoichi; Maki, Yoshinobu; Kagami, Noriaki; Satou, Ryouichi; Sugihara, Naoki

    2015-01-01

    The primary aim of the present study was to compare efficiency in detecting suspected caries requiring observation (CO) and decayed teeth (DT) between dental explorers and Community Periodontal Index (CPI)-probes in school dental examinations and evaluate the effect of their respective use on Decayed, Missing, Filled Teeth (DMFT) Index scores. A total of 126 elementary and high school students were examined. All the clinical findings were obtained by a pair of trained dentists examining each student at routine annual school dental examinations. A dental explorer or CPI-probe and dental mirror were used for the examination. One dentist used the dental explorer, while the other used the CPI-probe. The choice of which instrument to use by the first dentist to examine the student was made at random. A comparison of the explorers and CPI-probes revealed that the numbers of patients and permanent teeth classified as CO were greater with the former in 6th-grade elementary and high school students (p<0.05). The Kappa value for CO and DT was 0.560 for 6th-grade elementary school and 0.846 for high school students. All DMFT scores were higher with the explorers than with the CPI-probes in the 6th-grade elementary school students. No significant difference was observed between the explorers and CPI-probes in any of the DMFT scores in any group, however. The present results indicate that as long as the low rate of caries in Japanese school children is maintained, the epidemiological data on this disease should not show any significant change if a CPI-probe is used instead of an explorer in school dental examinations. PMID:26370573

  1. An in vitro comparison of diagnostic accuracy of cone beam computed tomography and phosphor storage plate to detect simulated occlusal secondary caries under amalgam restoration

    PubMed Central

    Shahidi, Shoaleh; Zadeh, Nahal Kazerooni; Sharafeddin, Farahnaz; Shahab, Shahriar; Bahrampour, Ehsan; Hamedani, Shahram

    2015-01-01

    Background: This study was aimed to compare the diagnostic accuracy and feasibility of cone beam computed tomography (CBCT) with phosphor storage plate (PSP) in detection of simulated occlusal secondary caries. Materials and Methods: In this in vitro descriptive-comparative study, a total of 80 slots of class I cavities were prepared on 80 extracted human premolars. Then, 40 teeth were randomly selected out of this sample and artificial carious lesions were created on these teeth by a round diamond bur no. 1/2. All 80 teeth were restored with amalgam fillings and radiographs were taken, both with PSP system and CBCT. All images were evaluated by three calibrated observers. The area under the receiver operating characteristic curve was used to compare the diagnostic accuracy of two systems. SPSS (SPSS Inc., Chicago, IL, USA) was adopted for statistical analysis. The difference between Az value of bitewing and CBCT methods were compared by pairwise comparison method. The inter- and intra-operator agreement was assessed by kappa analysis (P < 0.05). Results: The mean Az value for bitewings and CBCT was 0.903 and 0.994, respectively. Significant differences were found between PSP and CBCT (P = 0.010). The kappa value for inter-observer agreement was 0.68 and 0.76 for PSP and CBCT, respectively. The kappa value for intra-observer agreement was 0.698 (observer 1, P = 0.000), 0.766 (observer 2, P = 0.000) and 0.716 (observer 3, P = 0.000) in PSP method, and 0.816 (observer 1, P = 0.000), 0.653 (observer 2, P = 0.000) and 0.744 (observer 3, P = 0.000) in CBCT method. Conclusion: This in vitro study, with a limited number of samples, showed that the New Tom VGI Flex CBCT system was more accurate than the PSP in detecting the simulated small secondary occlusal caries under amalgam restoration. PMID:25878682

  2. Educational material of dental anatomy applied to study the morphology of permanent teeth.

    PubMed

    Siéssere, Selma; Vitti, Mathias; de Sousa, Luiz Gustavo; Semprini, Marisa; Regalo, Simone Cecílio Hallak

    2004-01-01

    The purpose of this report is to present educational material that would allow the dental student to learn to easily identify the morphologic characteristics of permanent teeth, and how they fit together (occlusion). In order to do this, macro models of permanent teeth with no attrition were carved in wax and later molded with alginate. These molds were filled with plaster, dental stone and/or cold-cured acrylic resin. The large individual dental stone tooth models were mounted on a wax base, thus obtaining maxillary and mandibular arches which were occluded. These dental arches were molded with plaster or dental stone. The authors suggest that these types of macro models allow an excellent visualization of the morphologic characteristics of permanent teeth and occlusion. Dental students are able to carve the permanent dentition in wax with great facility when they can observe macro models.

  3. Education About Dental Hygienists' Roles in Public Dental Prevention Programs: Dental and Dental Hygiene Students' and Faculty Members' and Dental Hygienists' Perspectives.

    PubMed

    Pervez, Anushey; Kinney, Janet S; Gwozdek, Anne; Farrell, Christine M; Inglehart, Marita R

    2016-09-01

    In 2005, Public Act No. 161 (PA 161) was passed in Michigan, allowing dental hygienists to practice in approved public dental prevention programs to provide services for underserved populations while utilizing a collaborative agreement with a supervising dentist. The aims of this study were to assess how well dental and dental hygiene students and faculty members and practicing dental hygienists have been educated about PA 161, what attitudes and knowledge about the act they have, and how interested they are in additional education about it. University of Michigan dental and dental hygiene students and faculty members, students in other Michigan dental hygiene programs, and dental hygienists in the state were surveyed. Respondents (response rate) were 160 dental students (50%), 63 dental hygiene students (82%), 30 dental faculty members (26%), and 12 dental hygiene faculty members (52%) at the University of Michigan; 143 dental hygiene students in other programs (20%); and 95 members of the Michigan Dental Hygienists' Association (10%). The results showed that the dental students were less educated about PA 161 than the dental hygiene students, and the dental faculty members were less informed than the dental hygiene faculty members and dental hygienists. Responding dental hygiene faculty members and dental hygienists had more positive attitudes about PA 161 than did the students and dental faculty members. Most of the dental hygiene faculty members and dental hygienists knew a person providing services in a PA 161 program. Most dental hygiene students, faculty members, and dental hygienists wanted more education about PA 161. Overall, the better educated about the program the respondents were, the more positive their attitudes, and the more interested they were in learning more. PMID:27587574

  4. Filling an Unvented Cryogenic Tank

    NASA Technical Reports Server (NTRS)

    Beck, Phillip; Willen, Gary S.

    1987-01-01

    Slow-cooling technique enables tank lacking top vent to be filled with cryogenic liquid. New technique: pressure buildup prevented through condensation of accumulating gas resulting in condensate being added to bulk liquid. Filling method developed for vibration test on vacuum-insulated spherical tank containing liquid hydrogen.

  5. 77 FR 12517 - VA Dental Insurance Program

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-01

    ...) Space maintenance. (iii) Restorative services. (A) Amalgam restorations. (B) Resin-based composite restorations. (iv) Endodontic services. (A) Pulp capping. (B) Pulpotomy and pulpectomy. (C) Root canal...

  6. Dental Assisting Program Guide.

    ERIC Educational Resources Information Center

    Georgia Univ., Athens. Dept. of Vocational Education.

    This program guide contains the standard dental assisting curriculum for technical institutes in Georgia. The curriculum encompasses the minimum competencies required for entry-level dental assistants, and includes job skills in the technical areas of preventive dentistry; four-handed dentistry; chairside assisting with emphasis in diagnostics,…

  7. Dental Charting. Student's Manual.

    ERIC Educational Resources Information Center

    Weaver, Trudy Karlene; Apfel, Maura

    This manual is part of a series dealing with skills and information needed by students in dental assisting. The individualized student materials are suitable for classroom, laboratory, or cooperative training programs. This student manual contains four units covering the following topics: dental anatomical terminology; tooth numbering systems;…

  8. Dental Laboratory Technician.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. Center on Education and Training for Employment.

    This document, which is designed for use in developing a tech prep competency profile for the occupation of dental laboratory technician, lists technical competencies and competency builders for 13 units pertinent to the health technologies cluster in general and 8 units to the occupation of dental laboratory technician. The following skill areas…

  9. Discrimination of tooth layers and dental restorative materials using cutting sounds.

    PubMed

    Zakeri, Vahid; Arzanpour, Siamak; Chehroudi, Babak

    2015-03-01

    Dental restoration begins with removing carries and affected tissues with air-turbine rotary cutting handpieces, and later restoring the lost tissues with appropriate restorative materials to retain the functionality. Most restoration materials eventually fail as they age and need to be replaced. One of the difficulties in replacing failing restorations is discerning the boundary of restorative materials, which causes inadvertent removal of healthy tooth layers. Developing an objective and sensor-based method is a promising approach to monitor dental restorative operations and to prevent excessive tooth losses. This paper has analyzed cutting sounds of an air-turbine handpiece to discriminate between tooth layers and two commonly used restorative materials, amalgam and composite. Support vector machines were employed for classification, and the averaged short-time Fourier transform coefficients were selected as the features. The classifier performance was evaluated from different aspects such as the number of features, feature scaling methods, classification schemes, and utilized kernels. The total classification accuracies were 89% and 92% for cases included composite and amalgam materials, respectively. The obtained results indicated the feasibility and effectiveness of the proposed method.

  10. The future dental workforce?

    PubMed

    Gallagher, J E; Wilson, N H F

    2009-02-28

    The Editor-in-Chief of the BDJ has previously raised important questions about dental workforce planning and the implications for dental graduates of recent changes and pressures. It is now time to revisit this issue. Much has changed since the last workforce review in England and Wales, and the rate of change is in all probability set to increase. First, at the time of writing this paper the momentous step of including dental care professionals (DCPs) on General Dental Council (GDC) registers in the United Kingdom has recently been completed. Second, the Scope of Practice of all dental professionals has been under consultation by the General Dental Council, and research evidence suggests that greater use should be made of skill-mix in the dental team. Third, within England, Lord Darzi has just published the 'Final Report of the NHS Next Stage Review', which emphasises 'quality care' and 'team-working' as key features of healthcare; this report was accompanied by an important document entitled 'A High Quality Workforce', in which plans for local workforce planning within the NHS are outlined, placing responsibilities at national, local and regional levels. Fourth, policy makers across the UK are wrestling with addressing oral health needs, promoting health and facilitating access to dental care, all of which have implications for the nature and shape of the dental workforce. Fifth, with the impact of globalisation and European policies we are net gainers of dentists as well as having more in training. Sixth, although there have been reviews and policy initiatives by regulatory, professional and other bodies in support of shaping the dental workforce, there has been little serious consideration of skill-mix and funding mechanisms to encourage team-working. Together, these events demand that we enter a fresh debate on the future dental workforce which should extend beyond professional and national boundaries and inform workforce planning. This debate is of great

  11. The future dental workforce?

    PubMed

    Gallagher, J E; Wilson, N H F

    2009-02-28

    The Editor-in-Chief of the BDJ has previously raised important questions about dental workforce planning and the implications for dental graduates of recent changes and pressures. It is now time to revisit this issue. Much has changed since the last workforce review in England and Wales, and the rate of change is in all probability set to increase. First, at the time of writing this paper the momentous step of including dental care professionals (DCPs) on General Dental Council (GDC) registers in the United Kingdom has recently been completed. Second, the Scope of Practice of all dental professionals has been under consultation by the General Dental Council, and research evidence suggests that greater use should be made of skill-mix in the dental team. Third, within England, Lord Darzi has just published the 'Final Report of the NHS Next Stage Review', which emphasises 'quality care' and 'team-working' as key features of healthcare; this report was accompanied by an important document entitled 'A High Quality Workforce', in which plans for local workforce planning within the NHS are outlined, placing responsibilities at national, local and regional levels. Fourth, policy makers across the UK are wrestling with addressing oral health needs, promoting health and facilitating access to dental care, all of which have implications for the nature and shape of the dental workforce. Fifth, with the impact of globalisation and European policies we are net gainers of dentists as well as having more in training. Sixth, although there have been reviews and policy initiatives by regulatory, professional and other bodies in support of shaping the dental workforce, there has been little serious consideration of skill-mix and funding mechanisms to encourage team-working. Together, these events demand that we enter a fresh debate on the future dental workforce which should extend beyond professional and national boundaries and inform workforce planning. This debate is of great

  12. Dental equipment test during zero-gravity flight

    NASA Technical Reports Server (NTRS)

    Young, John; Gosbee, John; Billica, Roger

    1991-01-01

    The overall objectives of this program were to establish performance criteria and develop prototype equipment for use in the Health Maintenance Facility (HMF) in meeting the needs of dental emergencies during space missions. The primary efforts during this flight test were to test patient-operator relationships, patent (manikin) restraint and positioning, task lighting systems, use and operation of dental rotary instruments, suction and particle containment system, dental hand instrument delivery and control procedures, and the use of dental treatment materials. The initial efforts during the flight focused on verification of the efficiency of the particle containment system. An absorptive barrier was also tested in lieu of the suction collector. To test the instrument delivery system, teeth in the manikin were prepared with the dental drill to receive restorations, some with temporary filling materials and another with definitive filling material (composite resin). The best particle containment came from the combination use of the laminar-air/suction collector in concert with immediate area suction from a surgical high-volume suction tip. Lighting in the treatment area was provided by a flexible fiberoptic probe. This system is quite effective for small areas, but for general tasks ambient illumination is required. The instrument containment system (elastic cord network) was extremely effective and easy to use. The most serious problem with instrument delivey and actual treatment was lack of time during the microgravity sequences. The restorative materials handled and finished well.

  13. What is dental ecology?

    PubMed

    Cuozzo, Frank P; Sauther, Michelle L

    2012-06-01

    Teeth have long been used as indicators of primate ecology. Early work focused on the links between dental morphology, diet, and behavior, with more recent years emphasizing dental wear, microstructure, development, and biogeochemistry, to understand primate ecology. Our study of Lemur catta at the Beza Mahafaly Special Reserve, Madagascar, has revealed an unusual pattern of severe tooth wear and frequent tooth loss, primarily the result of consuming a fallback food for which these primates are not dentally adapted. Interpreting these data was only possible by combining our areas of expertise (dental anatomy [FC] and primate ecology [MS]). By integrating theoretical, methodological, and applied aspects of both areas of research, we adopted the term "dental ecology"-defined as the broad study of how teeth respond to the environment. Specifically, we view dental ecology as an interpretive framework using teeth as a vehicle for understanding an organism's ecology, which builds upon earlier work, but creates a new synthesis of anatomy and ecology that is only possible with detailed knowledge of living primates. This framework includes (1) identifying patterns of dental pathology and tooth use-wear, within the context of feeding ecology, behavior, habitat variation, and anthropogenic change, (2) assessing ways in which dental development and biogeochemical signals can reflect habitat, environmental change and/or stress, and (3) how dental microstructure and macro-morphology are adapted to, and reflect feeding ecology. Here we define dental ecology, provide a short summary of the development of this perspective, and place our new work into this context. PMID:22610892

  14. Apical leakage following CO2 laser apicoectomy and conventional amalgam retrofilling: a comparative study in vitro

    NASA Astrophysics Data System (ADS)

    Pinheiro, Antonio L. B.; Cavalcanti, P. H. H. A.; Brugnera, Aldo, Jr.

    1999-05-01

    To perform this study, 40 extracted single rooted human teeth were used to compare dye leakage between apicoectomy following amalgam retrofill and apicoectomy using CO2 laser irradiation. All the 40 teeth were endodontically treated and than were separate in two groups of 20 teeth each. A bur was used to ressect the apexes of the sample of group I followed by silver amalgam retrofill. the 20 teeth of group II had their apexes ressected with a Carbon Dioxide laser beam. All the samples were submerged into a methylene blue dye solution, washed, longitudinally sectioned and graded upon the level of leakage by two separate examiners. The result showed a perfect concordance between both examiners and also, a non significant difference on the level of leakage in the two groups.

  15. Enhancement in resistivity resolution based on the data sets amalgamation technique at Bukit Bunuh, Perak, Malaysia

    NASA Astrophysics Data System (ADS)

    Anderson Bery, Andy; Saad, Rosli; Hidayah, I. N. E.; Azwin, I. N.; Saidin, Mokhtar

    2015-01-01

    In this paper, we have carried out a study with the main objective to enhance the resolution of the electrical resistivity inversion model by introducing the data sets amalgamation technique to be used in the data processing stage. Based on the model resistivity with topography results, the data sets amalgamation technique for pole-dipole and wenner- schlumberger arrays are successful in identifying the boundary or interface of the overburden and weathered granite. Although the electrical resistivity method is well known, the proper selection of an array and appropriate inversion parameters setting such as damping factors are important in order to achieve the study objective and to image the target at the Earth's subsurface characterizations.

  16. Health Instruction Packages: Permanent Teeth, Dental Deposits, and Dental Instruments. Dientes Permanentes, Depositos Dentales y Instrumentos Dentales.

    ERIC Educational Resources Information Center

    Lind, Patricia; Germano, Catherine

    These five learning modules use text interspersed with illustrations and reinforcement exercises to instruct dental aide and dental hygiene students about jaw bones and gums, dental deposits, and dental instruments. The first four modules were prepared by Patricia Lind in both Spanish and English. "The Gum and Bone of Permanent Teeth" ("La Encia y…

  17. Dental journals: yesterday and today.

    PubMed

    Woodmansey, Karl

    2012-10-01

    Today's dentists may subscribe to, or receive complimentarily, a number of periodical publications containing technical professional information. Dental journals are the prime example: providing timely, reliable and useful information. The development of dental journals is a component of the evolution of scientific communication. This article reviews the origins and evolution of dental journals, including the Texas Dental Journal. PMID:23311024

  18. In vitro corrosion behaviour and microhardness of high-copper amalgams with platinum and indium.

    PubMed

    Ilikli, B G; Aydin, A; Işimer, A; Alpaslan, G

    1999-02-01

    Samples prepared from Luxalloy, GS-80, Permite-C and Logic and polished after 24 h by traditional methods were stored in polypropylene tubes containing phosphate-buffered saline solutions (pH 3.5 and 6.5) and distilled water. The amounts of mercury, silver, tin, copper, zinc, platinum and indium in the test solutions were determined at the first, second, eighth, 52nd and 78th week by atomic absorption spectrometry. At the end of the eighth week the amalgam samples were removed from solutions and evaluated by Rockwell Super Scial Microhardness tester. Statistically significant low amounts of metal ions were measured for Permite-C containing indium and Logic containing platinum. The microhardness test results showed that there were statistically significant increases in the microhardness of Permite-C and Logic. As a result it was shown that the amalgam samples were affected from corrosion conditions to different degrees. Sample of the Logic group that was stored in distilled water, showed smoother surface properties than other amalgam samples containing high copper. However, it was observed that samples of Permite-C group had the smoothest surface properties.

  19. Effect of masticatory cycles on tooth compression and resultant leakage of amalgam retrofills.

    PubMed

    Blum, J Y; Esber, S; Parahy, E; Franquin, J C

    1997-10-01

    This study was carried out to investigate the effect of changes in tooth structure due to masticatory cycles on amalgam retrofillings performed to different cavity depths. Forty upper maxillary first molars were tested. In the obturated palatal root apical amalgam was inserted to different depths (1.5 and 3 mm). Eight casts were built, each having four sample molars. To block the teeth, the vestibular roots were embedded in resin (palatal root was left free). The eight remaining retrofilled teeth served as controls and were not submitted to occlusal forces. A mechanical device to simulate masticatory cycles subjected the teeth to 500,000 to three million cycles. Leakage was assessed from dye penetration observations. The values of microleakage were analyzed and compared, and strain gauges were used to assess structural modifications to the tooth. The leakage of all retrofilled obturations increased in correlation with the number of masticatory cycles. At three million cycles, root length compression was 0.3 +/- 0.02%. Leakage was significantly less for the deeper cavity preparations at all stages. This in vitro study suggests a significant effect by root compression due to masticatory loads on the leakage of retrofilled amalgam obturations. PMID:9587270

  20. Antibacterial properties of amalgam and composite resin materials used as cores under crowns.

    PubMed

    Al Ghadban, A; Al Shaarani, F

    2012-06-01

    The Aim of this Study was to compare the bacterial growth in the bulk of both amalgam and fluoridated composite resin materials used as cores under crowns at core's surface (in the superficial area of the bulk) and depth levels. With 24 lower premolars, 12 of them were restored with metal posts and amalgam cores (group 1). The rest were restored with glass Fiber-reinforced Composite (FRC) posts and fluoridated composite resin cores (group 2). All specimens were covered with aluminium crowns cemented with resin cement, and then they were soaked in natural saliva for three months. Excoriations abraded from the superficial and the depth areas of the core materials were cultured under aerobic conditions on blood agar plates. After incubation for 2 days, colonies formed on the plates were identified, and the CFU mg(-1) counts were recorded accordingly. Statistical analysis was performed using an independent sample T test. The mean values of CFU mg(-1) counts in group 2 excoriations (surface 39.75, and depth 9.75) were higher than the group 1 excoriations (surface 1.67, and depth 0.42). This study supports the use of amalgam for building up cores due to its antibacterial properties. Composite resin, however, enhanced sizable bacterial growth despite the presence of fluoride. PMID:22852523

  1. Determination of the cathode and anode voltage drops in high power low-pressure amalgam lamps

    SciTech Connect

    Vasilyak, L. M.; Vasiliev, A. I. Kostyuchenko, S. V.; Sokolov, D. V.; Startsev, A. Yu.; Kudryavtsev, N. N.

    2011-12-15

    For the first time, cathode and anode drops of powerful low-pressure amalgam lamps were measured. The lamp discharge current is 3.2 A, discharge current frequency is 43 kHz, linear electric power is 2.4 W/cm. The method of determination of a cathode drop is based on the change of a lamp operating voltage at variation of the electrode filament current at constant discharge current. The total (cathode plus anode) drop of voltage was measured by other, independent ways. The maximum cathode fall is 10.8 V; the anode fall corresponding to the maximal cathode fall is 2.4 V. It is shown that in powerful low pressure amalgam lamps the anode fall makes a considerable contribution (in certain cases, the basic one) to heating of electrodes. Therefore, the anode fall cannot be neglected, at design an electrode and ballast of amalgam lamps with operating discharge current frequency of tens of kHz.

  2. Antibacterial properties of amalgam and composite resin materials used as cores under crowns.

    PubMed

    Al Ghadban, A; Al Shaarani, F

    2012-06-01

    The Aim of this Study was to compare the bacterial growth in the bulk of both amalgam and fluoridated composite resin materials used as cores under crowns at core's surface (in the superficial area of the bulk) and depth levels. With 24 lower premolars, 12 of them were restored with metal posts and amalgam cores (group 1). The rest were restored with glass Fiber-reinforced Composite (FRC) posts and fluoridated composite resin cores (group 2). All specimens were covered with aluminium crowns cemented with resin cement, and then they were soaked in natural saliva for three months. Excoriations abraded from the superficial and the depth areas of the core materials were cultured under aerobic conditions on blood agar plates. After incubation for 2 days, colonies formed on the plates were identified, and the CFU mg(-1) counts were recorded accordingly. Statistical analysis was performed using an independent sample T test. The mean values of CFU mg(-1) counts in group 2 excoriations (surface 39.75, and depth 9.75) were higher than the group 1 excoriations (surface 1.67, and depth 0.42). This study supports the use of amalgam for building up cores due to its antibacterial properties. Composite resin, however, enhanced sizable bacterial growth despite the presence of fluoride.

  3. Dental student debt.

    PubMed

    Mannion, H; Bedi, R

    1995-09-01

    The aim of this investigation is to provide information about the financial status of dental students enrolled on the Bachelor of Dental Surgery degree course at the University of Birmingham. All undergraduate dental students enrolled during the academic year 1993-94 were asked to participate in the study. The pre-tested questionnaire, which was given to all students, covered personal details, expenditure levels, income, loans, overdrafts, use of government schemes ('top-up loans'), and so on. The questionnaire was completed by 115 dental students (response rate 47%). The results showed that dental students' debts increased each year throughout the course. A top-up loan (range 700 Pounds-850 Pounds) had been taken out by 36% of students. The financial status of 9% of students was severe enough to warrant their eligibility for awards from access funds. Credit cards were possessed by 52% of the surveyed students, and although only half of these owed money, 22% owed between 500 Pounds and 2000 Pounds. Personal overdrafts were held by 56% of respondents. A total of 17% of students engaged in weekly part-time employment. The average debt for final year students was 1200 Pounds. Dental students' estimates of the level of debt they were likely to incur was greater than the actual debt presently experienced by final year students. In conclusion, this preliminary study showed that most dental students incur debt during their undergraduate course and that this debt increases during the course.

  4. Amalgam tattoo: report of an unusual clinical presentation and the use of energy dispersive X-ray analysis as an aid to diagnosis

    SciTech Connect

    McGinnis, J.P. Jr.; Greer, J.L.; Daniels, D.S.

    1985-01-01

    An unusual appearing gingival amalgam pigmentation (amalgam tattoo) that completely surrounded the maxillary right first premolar in a 13-year-old boy is presented. Because of the wide distribution and apparent clinical progression of the discoloration, an excisional biopsy was performed. The histopathologic diagnosis of amalgam pigmentation was confirmed in paraffin sections by energy dispersive X-ray microanalysis. Silver, tin, and mercury were detected in the specimen.

  5. Modelling community, family, and individual determinants of childhood dental caries.

    PubMed

    Duijster, Denise; van Loveren, Cor; Dusseldorp, Elise; Verrips, Gijsbert H W

    2014-04-01

    This cross-sectional study empirically tested a theoretical model of pathways and inter-relationships among community, family, and individual determinants of childhood dental caries in a sample of 630, 6-year-old children from the Netherlands. Children's decayed, missing, and filled teeth (dmft) scores were extracted from dental records. A validated parental questionnaire was used to collect data on sociodemographic characteristics, psychosocial factors, and oral hygiene behaviours. Data on neighbourhood quality were obtained from the Dutch Central Bureau of Statistics. Structural equation modelling indicated that the model was valid after applying a few modifications. In the revised model, lower maternal education level was related to poorer family organization, lower levels of social support, lower dental self-efficacy, and an external dental health locus of control. These, in turn, were associated with poorer oral hygiene behaviours, which were linked to higher levels of childhood dental caries. In addition, lower maternal education level and poorer neighbourhood quality were directly associated with higher caries levels in children. This model advances our understanding of determinants of childhood dental caries and the pathways in which they operate. Conception of these pathways is essential for guiding the development of caries-preventive programmes for children. Clues for further development of the model are suggested.

  6. Relationship between dietary intake and dental caries in preschool children.

    PubMed

    Yen, Chin-En; Huang, Yi-Chia; Hu, Suh-Woan

    2010-06-01

    This study assessed the relationship between intake of nutrients and dental caries in preschool children. One hundred and eighty-two children aged three to six years were recruited from nine day care centers in central Taiwan. These children had an oral health examination, and their parents or guardians answered a questionnaire. Each child's intake of nutrients was estimated using the 24-hour dietary recall and food frequency questionnaire data. Logistic regression analysis was applied to assess the associations between dental caries and intake of each nutrient or food group, with adjustment for potential confounders. The prevalence of dental caries was 73 % and increased with age. Not being a first-born and having more between-meal snacks were associated with increased caries risk. After controlling for other important factors, vitamin A intake was significantly associated with fewer dental caries (deft, decayed, indicated for extraction, and filled primary teeth: ≥ 4 vs. < 4), with an odds ratio of 0.97 (95 % confidence interval: 0.94 - 0.99) for an 100-μg increase in vitamin A intake. There was no significant association between dental caries and energy, macronutrient intake, and Ca/P ratio, respectively. Vegetable intake was also significantly associated with lower dental caries score.

  7. Dental fear and alexithymia among adults in Finland.

    PubMed

    Pohjola, Vesa; Mattila, Aino K; Joukamaa, Matti; Lahti, Satu

    2011-07-01

    population sample, controlling for age, gender, education and marital status as well as depressive and anxiety disorders. An additional aim was to evaluate whether gender modified this association. MATERIAL AND METHODS. The two-stage stratified cluster sample (n = 8028) represented the Finnish population aged 30 years and older. Participants (n = 5241) answered the question 'How afraid are you of visiting a dentist?' They also filled out the 20-Item Toronto Alexithymia Scale (TAS-20), which included three sub-scales, i.e. difficulties in identifying feelings (DIF), difficulties in describing feelings (DDF) and externally oriented thinking (EOT). Anxiety and depressive disorders were assessed with a standardized structured psychiatric interview according to DSM-IV criteria. To evaluate the association between dental fear and alexithymia, multiple logistic regression analyses were performed, adjusting simultaneously for the effects of possible confounding variables. RESULTS. Gender modified the association between dental fear and alexithymia. Among women, those reporting higher scores for TAS-20, DIF and EOT sub-scale scores were more likely to have high dental fear than were those reporting lower scores. Among men no such association was observed. Those participants who reported high DDF sub-scale scores were more likely to have high dental fear than were those reporting lower scores. CONCLUSIONS. Alexithymics are more likely to have high dental fear than non-alexithymics are. The findings support the suggestion that some people with dental fear may have internal personality vulnerability to anxiety disorders. PMID:21294672

  8. Dental composite resins: measuring the polymerization shrinkage using optical fiber Bragg grating sensors

    NASA Astrophysics Data System (ADS)

    Ottevaere, H.; Tabak, M.; Chah, K.; Mégret, P.; Thienpont, H.

    2012-04-01

    Polymerization shrinkage of dental composite materials is recognized as one of the main reasons for the development of marginal leakage between a tooth and filling material. As an alternative to conventional measurement methods, we propose optical fiber Bragg grating (FBG) based sensors to perform real-time strain and shrinkage measurements during the curing process of dental resin cements. We introduce a fully automated set-up to measure the Bragg wavelength shift of the FBG strain sensors and to accurately monitor the linear strain and shrinkage of dental resins during curing. Three different dental resin materials were studied in this work: matrix-filled BisGMA-based resins, glass ionomers and organic modified ceramics.

  9. Economic impact of dental hygienists on solo dental practices.

    PubMed

    Lazar, Vickie F; Guay, Albert H; Beazoglou, Tryfon J

    2012-08-01

    The fact that a significant percentage of dentists employ dental hygienists raises an important question: Are dental practices that utilize a dental hygienist structurally and operationally different from practices that do not? This article explores differences among dental practices that operate with and without dental hygienists. Using data from the American Dental Association's 2003 Survey of Dental Practice, a random sample survey of U.S. dentists, descriptive statistics were used to compare selected characteristics of solo general practitioners with and without dental hygienists. Multivariate regression analysis was used to estimate the effect of dental hygienists on the gross billings and net incomes of solo general practitioners. Differences in practice characteristics--such as hours spent in the practice and hours spent treating patients, wait time for a recall visit, number of operatories, square feet of office space, net income, and gross billings--were found between solo general practitioners who had dental hygienists and those who did not. Solo general practitioners with dental hygienists had higher gross billings. Higher gross billings would be expected, as would higher expenses. However, net incomes of those with dental hygienists were also higher. In contrast, the mean waiting time for a recall visit was higher among dentists who employed dental hygienists. Depending on personal preferences, availability of qualified personnel, etc., dentists who do not employ dental hygienists but have been contemplating that path may want to further research the benefits and opportunities that may be realized.

  10. Irrational Fixed Dose Combinations & Need for Intervention: Understanding of Dental Clinicians and Residents

    PubMed Central

    Sharma, Amit; Singh, Vikas; Pilania, Dinesh; Sharma, Yogesh Kumar

    2014-01-01

    Context: There is a growing concern about ever-burgeoning list of irrational fixed dose combinations (FDCs) which have flooded pharmaceutical market recently in India. Till date no structured study has evaluated the level of understanding among the dental clinicians and residents about these concepts. The present study is designed to fulfil that lacuna. Objective: To evaluate the knowledge, attitude and practice, regarding the use of FDCs by the dental residents and dental clinicians in a tertiary care teaching dental hospital. Materials and Methods: The present study was carried out among postgraduate students and dental clinicians working at Rajasthan Dental College, a tertiary care teaching dental hospital, in Jaipur, India. Sixty residents and 77 dental clinicians from the departments of Orthodontics, Prosthodontics, Oral Medicine, Periodontology, Conservative Dentistry & Endodontics, Oral & Maxillofacial Surgery, Pedodontics who gave their informed consent were enrolled. A prevalidated questionnaire regarding knowledge, attitude and prescribing practice of fixed dose combinations was filled up. Data was analysed with suitable statistical tests. Results: Out of the 60 residents and 77 dental clinicians recruited for the study, none of them were aware about all of the advantages and disadvantages of FDCs. On an average, only 47% of residents and 61% dental clinicians were aware of FDC included in WHO Essential Medicines List (EML). Only 47% residents and 58% dental clinicians could recall a single banned FDC in India. Common sources of information about FDCs were Monthly Index of Medical Specialities (MIMS), medical representatives and internet. The most commonly prescribed irrational FDC was diclofenac + paracetamol combination, 42% residents and 41% dental clinicians and residents believed that regular Continuous Medical Education (CMEs) stressing upon rational use of medicine could reduce the magnitude of this problem. Conclusion: It is the need of the hour

  11. Dental care - child

    MedlinePlus

    ... Zakher B, Mitchell JP, Pappas M. Preventing dental caries in children <5 years: systematic review updating USPSTF ... chap 7. Ng MW, Chase I. Early childhood caries: risk-based disease prevention and management. Dent Clin ...

  12. Dental mesenchymal stem cells.

    PubMed

    Sharpe, Paul T

    2016-07-01

    Mammalian teeth harbour mesenchymal stem cells (MSCs), which contribute to tooth growth and repair. These dental MSCs possess many in vitro features of bone marrow-derived MSCs, including clonogenicity, expression of certain markers, and following stimulation, differentiation into cells that have the characteristics of osteoblasts, chondrocytes and adipocytes. Teeth and their support tissues provide not only an easily accessible source of MSCs but also a tractable model system to study their function and properties in vivo In addition, the accessibility of teeth together with their clinical relevance provides a valuable opportunity to test stem cell-based treatments for dental disorders. This Review outlines some recent discoveries in dental MSC function and behaviour and discusses how these and other advances are paving the way for the development of new biologically based dental therapies. PMID:27381225

  13. Glossary of Dental Terms

    MedlinePlus

    ... geta poker friv Home InfoBites Find an AGD Dentist Your Family's Oral Health About the AGD Dental ... and shape of teeth performed by a general dentist | More Edentulous having lost most or all of ...

  14. Infant dental care (image)

    MedlinePlus

    Even though newborns and infants do not have teeth, care of the mouth and gums is important. ... sugar water. As the child grows, establishing proper dental hygiene will promote healthy teeth and gums which ...

  15. Dental Care in Pregnancy

    MedlinePlus

    ... for you and your baby and contain less sugar that can damage your teeth. Water or low-fat milk hydrates you and contains little or no sugar. For More Information American Dental Association: Pregnancy http : / / ...

  16. Mercury and Other Biomedical Waste Management Practices among Dental Practitioners in India

    PubMed Central

    Singh, Raghuwar D.; Jurel, Sunit K.; Tripathi, Shuchi; Agrawal, Kaushal K.; Kumari, Reema

    2014-01-01

    Objectives. The objective of the study was to assess the awareness and performance towards dental waste including mercury management policy and practices among the dental practitioners in North India. Materials and Methods. An epidemiologic survey was conducted among 200 private dental practitioners. The survey form was composed of 29 self-administered questions frame based on knowledge, attitude, and those regarding the practices of dentists in relation to dental health-care waste management. The resulting data were coded and a statistical analysis was done. Results and Discussion. About 63.7% of the dentists were not aware of the different categories of biomedical waste generated in their clinics. Only 31.9% of the dentists correctly said that outdated and contaminated drugs come under cytotoxic waste. 46.2% said they break the needle and dispose of it and only 21.9% use needle burner to destroy it. 45.0% of the dentists dispose of the developer and fixer solutions by letting them into the sewer, 49.4% of them dilute the solutions and let them into sewer and only 5.6% return them to the supplier. About 40.6% of the dentists dispose of excess silver amalgam by throwing it into common bin. Conclusion. It was concluded that not all dentists were aware of the risks they were exposed to and only half of them observe infection control practices. PMID:25162005

  17. Dental arch asymmetry

    PubMed Central

    Al-Zubair, Nabil Muhsen

    2014-01-01

    Objective: This study was conducted to assess the dental arch asymmetry in a Yemeni sample aged (18-25) years. Materials and Methods: The investigation involved clinical examination of 1479 adults; only 253 (129 females, 124 males) out of the total sample were selected to fulfill the criteria for the study sample. Study models were constructed and evaluated to measure mandibular arch dimensions. Three linear distances were utilized on each side on the dental arch: Incisal-canine distance, canine-molar distance and incisal-molar distance, which represent the dental arch segmental measurements. Results: When applying “t-test” at P < 0.05, no significant differences were found between the right and left canine-molar, incisal-canine and incisal-molar distances in both dental arches for both sexes. The greater variation (0.30 mm) was observed between right and left canine-molar distance in the maxillary dental arch in male and the smaller (0.04 mm) in the mandibular dental arch between the right and left canine-molar distance in females. Conclusion: The findings of the present study revealed a symmetrical pattern of dental arches, since the right and left sides showed no statistically significant difference. In general, it can be observed that the measurements related to the central incisors and canines have the widest range of reading and give the impression that the location of central incisor and canines to each other and to other teeth is the strongest factor in determining the dental arch asymmetry. PMID:24966774

  18. Dental (Odontogenic) Pain

    PubMed Central

    Renton, Tara

    2011-01-01

    This article provides a simple overview of acute trigeminal pain for the non dentist. This article does not cover oral mucosal diseases (vesiculobullous disorders) that may cause acute pain. Dental pain is the most common in this group and it can present in several different ways. Of particular interest for is that dental pain can mimic both trigeminal neuralgia and other chronic trigeminal pain disorders. It is crucial to exclude these disorders whilst managing patients with chronic trigeminal pain. PMID:26527224

  19. Dental operatory water lines.

    PubMed

    Beierle, J W

    1993-02-01

    Water samples were collected from dental handpiece and air-water syringe lines at various times during the day and cultured for the presence and prevalence of various microbes. It was found that the longer a dental unit was out of use, the greater the microbial build-up in water lines. However, purging lines for two to three minutes at the start of the day and between patients significantly reduced microbial presence.

  20. Portable Dental System

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Portable dental system provides dental care in isolated communities. System includes a patient's chair and a dentist's stool, an X-ray machine and a power unit, all of which fold into compact packages. A large yellow "pumpkin" is a collapsible compressed air tank. Portable system has been used successfully in South America in out of the way communities with this back-packable system, and in American nursing homes. This product is no longer manufactured.

  1. Saliva and dental erosion

    PubMed Central

    BUZALAF, Marília Afonso Rabelo; HANNAS, Angélicas Reis; KATO, Melissa Thiemi

    2012-01-01

    Dental erosion is a multifactorial condition. The consideration of chemical, biological and behavioral factors is fundamental for its prevention and therapy. Among the biological factors, saliva is one of the most important parameters in the protection against erosive wear. Objective This review discusses the role of salivary factors on the development of dental erosion. Material and Methods A search was undertaken on MEDLINE website for papers from 1969 to 2010. The keywords used in the research were "saliva", "acquired pellicle", "salivary flow", "salivary buffering capacity" and "dental erosion". Inclusion of studies, data extraction and quality assessment were undertaken independently and in duplicate by two members of the review team. Disagreements were solved by discussion and consensus or by a third party. Results Several characteristics and properties of saliva play an important role in dental erosion. Salivary clearance gradually eliminates the acids through swallowing and saliva presents buffering capacity causing neutralization and buffering of dietary acids. Salivary flow allows dilution of the acids. In addition, saliva is supersaturated with respect to tooth mineral, providing calcium, phosphate and fluoride necessary for remineralization after an erosive challenge. Furthermore, many proteins present in saliva and acquired pellicle play an important role in dental erosion. Conclusions Saliva is the most important biological factor affecting the progression of dental erosion. Knowledge of its components and properties involved in this protective role can drive the development of preventive measures targeting to enhance its known beneficial effects. PMID:23138733

  2. Dental materials for cleft palate repair.

    PubMed

    Sharif, Faiza; Ur Rehman, Ihtesham; Muhammad, Nawshad; MacNeil, Sheila

    2016-04-01

    Numerous bone and soft tissue grafting techniques are followed to repair cleft of lip and palate (CLP) defects. In addition to the gold standard surgical interventions involving the use of autogenous grafts, various allogenic and xenogenic graft materials are available for bone regeneration. In an attempt to discover minimally invasive and cost effective treatments for cleft repair, an exceptional growth in synthetic biomedical graft materials have occurred. This study gives an overview of the use of dental materials to repair cleft of lip and palate (CLP). The eligibility criteria for this review were case studies, clinical trials and retrospective studies on the use of various types of dental materials in surgical repair of cleft palate defects. Any data available on the surgical interventions to repair alveolar or palatal cleft, with natural or synthetic graft materials was included in this review. Those datasets with long term clinical follow-up results were referred to as particularly relevant. The results provide encouraging evidence in favor of dental and other related biomedical materials to fill the gaps in clefts of lip and palate. The review presents the various bones and soft tissue replacement strategies currently used, tested or explored for the repair of cleft defects. There was little available data on the use of synthetic materials in cleft repair which was a limitation of this study. In conclusion although clinical trials on the use of synthetic materials are currently underway the uses of autologous implants are the preferred treatment methods to date.

  3. 42 CFR Appendix G to Part 75 - Standards for Licensing Dental Hygienists and Dental Assistants in Dental Radiography

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Standards for Licensing Dental Hygienists and Dental Assistants in Dental Radiography G Appendix G to Part 75 Public Health PUBLIC HEALTH SERVICE...—Standards for Licensing Dental Hygienists and Dental Assistants in Dental Radiography The following...

  4. 42 CFR Appendix G to Part 75 - Standards for Licensing Dental Hygienists and Dental Assistants in Dental Radiography

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Standards for Licensing Dental Hygienists and Dental Assistants in Dental Radiography G Appendix G to Part 75 Public Health PUBLIC HEALTH SERVICE...—Standards for Licensing Dental Hygienists and Dental Assistants in Dental Radiography The following...

  5. 42 CFR Appendix G to Part 75 - Standards for Licensing Dental Hygienists and Dental Assistants in Dental Radiography

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Standards for Licensing Dental Hygienists and Dental Assistants in Dental Radiography G Appendix G to Part 75 Public Health PUBLIC HEALTH SERVICE...—Standards for Licensing Dental Hygienists and Dental Assistants in Dental Radiography The following...

  6. 42 CFR Appendix G to Part 75 - Standards for Licensing Dental Hygienists and Dental Assistants in Dental Radiography

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Standards for Licensing Dental Hygienists and Dental Assistants in Dental Radiography G Appendix G to Part 75 Public Health PUBLIC HEALTH SERVICE...—Standards for Licensing Dental Hygienists and Dental Assistants in Dental Radiography The following...

  7. 42 CFR Appendix G to Part 75 - Standards for Licensing Dental Hygienists and Dental Assistants in Dental Radiography

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Standards for Licensing Dental Hygienists and Dental Assistants in Dental Radiography G Appendix G to Part 75 Public Health PUBLIC HEALTH SERVICE...—Standards for Licensing Dental Hygienists and Dental Assistants in Dental Radiography The following...

  8. Dental pain and associated factors among pregnant women: an observational study.

    PubMed

    Krüger, Marta S M; Lang, Celina A; Almeida, Luiza H S; Bello-Corrêa, Fernanda O; Romano, Ana R; Pappen, Fernanda G

    2015-03-01

    The present study aimed to determine the prevalence of dental pain during pregnancy and its association with sociodemographic factors and oral health conditions among 315 pregnant women in South Brazil. Participants were interviewed to obtain sociodemographic data, such as age, educational level, employment status, family income, and marital and parity status. Medical and dental histories were also collected, including the occurrence of dental pain and the use of dental services during pregnancy. Clinical examinations were performed to assess the presence of visible plaque and gingival bleeding and to calculate the decayed, missing, and filled teeth index. Means and standard deviations of continuous variables and frequencies and percentages of categorical variables were calculated. Independent variables were included in a multivariate logistic regression analysis. A total of 173 (54.9 %) pregnant women reported dental pain during pregnancy. After adjustment of the analysis, caries activity remained the main determinant of dental pain (odds ratio 3.33, 95 % CI 1.67-6.65). The prevalence of dental pain during pregnancy was high and the presence of caries activity was a determinant of dental pain. Moreover, access to oral health care was low, despite pregnant women's increased need for dental assistance. PMID:24894731

  9. Biological approaches toward dental pulp regeneration by tissue engineering.

    PubMed

    Sun, Hai-Hua; Jin, Tao; Yu, Qing; Chen, Fa-Ming

    2011-04-01

    Root canal therapy has been the predominant approach in endodontic treatment, wherein the entire pulp is cleaned out and replaced with a gutta-percha filling. However, living pulp is critical for the maintenance of tooth homeostasis and essential for tooth longevity. An ideal form of therapy, therefore, might consist of regenerative approaches in which diseased/necrotic pulp tissues are removed and replaced with regenerated pulp tissues to revitalize the teeth. Dental pulp regeneration presents one of the most challenging issues in regenerative dentistry due to the poor intrinsic ability of pulp tissues for self-healing and regrowth. With the advent of modern tissue engineering and the discovery of dental stem cells, biological therapies have paved the way to utilize stem cells, delivered or internally recruited, to generate dental pulp tissues, where growth factors and a series of dentine extracellular matrix molecules are key mediators that regulate the complex cascade of regeneration events to be faithfully fulfilled.

  10. Imagistic evaluation of direct dental restoration: en face OCT versus SEM and microCT

    NASA Astrophysics Data System (ADS)

    Negruţiu, Meda L.; Sinescu, Cosmin; Topala, Florin; Ionita, Ciprian; Marcauteanu, Corina; Petrescu, Emanuela L.; Podoleanu, Adrian G.

    2011-06-01

    There are several methods known which are used to assess the quality of direct dental restorations, but most of them are invasive. These lead to the destruction of the probes and often no conclusion could be drawn in respect to the existence of any microleakage in the investigated areas of interest. Optical tomographic techniques are of particular importance in the medical imaging field, because these techniques can provide non-invasive diagnostic images. Using an en-face version of OCT, we have recently demonstrated real time thorough evaluation of quality of dental fillings. The purpose of this in vitro study was to validate the en face OCT imagistic evaluation of direct dental restoration by using scanning electron microscopy (SEM) and microcomputer tomography (μCT). Teeth after several treatment methods are imaged in order to detect material defects and to asses the marginal adaptation at the dental hard tissue walls. SEM investigations evidenced the nonlinear aspect of the interface between the filling material and the buccal and lingual walls in some samples. The results obtained by μCT revealed also some material defects inside the fillings and at the interfaces with the rootcanal walls. The advantages of the OCT method consist in non-invasiveness and high resolution. En face OCT investigations permit to visualize a more complex stratificated structure at the interface filling material/dental hard tissue and in the apical region.

  11. Amalgam, an axon guidance Drosophila adhesion protein belonging to the immunoglobulin superfamily: over-expression, purification and biophysical characterization.

    PubMed

    Zeev-Ben-Mordehai, Tzviya; Paz, Aviv; Peleg, Yoav; Toker, Lilly; Wolf, Sharon G; Rydberg, Edwin H; Sussman, Joel L; Silman, Israel

    2009-02-01

    Amalgam, a multi-domain member of the immunoglobulin superfamily, possesses homophilic and heterophilic cell adhesion properties. It is required for axon guidance during Drosophila development in which it interacts with the extracellular domain of the transmembrane protein, neurotactin, to promote adhesion. Amalgam was heterologously expressed in Pichia pastoris, and the secreted protein product, bearing an NH(2)-terminal His(6)Tag, was purified from the growth medium by metal affinity chromatography. Size exclusion chromatography separated the purified protein into two fractions: a major, multimeric fraction and a minor, dimeric one. Two protocols to reduce the percentage of multimers were tested. In one, protein induction was performed in the presence of the zwitterionic detergent CHAPS, yielding primarily the dimeric form of amalgam. In a second protocol, agitation was gradually reduced during the course of the induction and antifoam was added daily to reduce the air/liquid interfacial foam area. This latter protocol lowered the percentage of multimer 2-fold, compared to constant agitation. Circular dichroism measurements showed that the dimeric fraction had a high beta-sheet content, as expected for a protein with an immunoglobulin fold. Dynamic light scattering and sedimentation velocity measurements showed that the multimeric fraction displays a monodisperse distribution, with R(H)=16 nm. When co-expressed together with amalgam the ectodomain of neurotactin copurified with it. Furthermore, both purified fractions of amalgam were shown to interact with Torpedo californica acetylcholinesterase, a structural homolog of neurotactin.

  12. Evaluating the Relationship of Dental Fear with Dental Health Status and Awareness

    PubMed Central

    2016-01-01

    Introduction Dental fear is one of the most common problems in dentistry, for both the patient and for the dentist. This issue can have an important effect on an individual’s dental health. Aim The aim of this paper was to report on the prevalence of dental anxiety and to explore if high levels of anxiety are associated with sociodemographic factors, oral health status, and level of oral health awareness. Materials and Methods The sample for this cross-sectional study included 294 patients (154 males and 140 females). All participants filled out a Dental Fear Survey (DFS) to evaluate their level of dental fear. Gender, age, education level, socioeconomic status and oral health awareness were also noted. Oral health behaviors and oral health awareness levels were investigated using seven questions. Also, the periodontal status of all participants was evaluated using the Community Periodontal Index of Treatment Needs (CPITN). Differences between different subgroups were tested using the chi-square test. Results There was a statistically significant difference between the DFS groups with regard to sociodemographic data. Women had significantly higher scores than men, and young patients had significantly higher scores than others. Patients with low education levels and low socioeconomic status had high DFS scores. Periodontal status was better in groups that had scores in the low and moderate ranges compared to groups that had high scores on the DFS. There was a statistically significant difference between the groups of DFS and CPITN (p<0.05). Patients with low and moderate levels of DFS answered the oral health knowledge questions correctly. There was a statistically significant difference between the DFS groups based on correct answers to the oral health knowledge questions (p<0.05). Conclusion The elimination of dental fear is very important and should be treated according to a patient-centered assessment. These individuals were informed about the dental treatment

  13. Evaluating the Relationship of Dental Fear with Dental Health Status and Awareness

    PubMed Central

    2016-01-01

    Introduction Dental fear is one of the most common problems in dentistry, for both the patient and for the dentist. This issue can have an important effect on an individual’s dental health. Aim The aim of this paper was to report on the prevalence of dental anxiety and to explore if high levels of anxiety are associated with sociodemographic factors, oral health status, and level of oral health awareness. Materials and Methods The sample for this cross-sectional study included 294 patients (154 males and 140 females). All participants filled out a Dental Fear Survey (DFS) to evaluate their level of dental fear. Gender, age, education level, socioeconomic status and oral health awareness were also noted. Oral health behaviors and oral health awareness levels were investigated using seven questions. Also, the periodontal status of all participants was evaluated using the Community Periodontal Index of Treatment Needs (CPITN). Differences between different subgroups were tested using the chi-square test. Results There was a statistically significant difference between the DFS groups with regard to sociodemographic data. Women had significantly higher scores than men, and young patients had significantly higher scores than others. Patients with low education levels and low socioeconomic status had high DFS scores. Periodontal status was better in groups that had scores in the low and moderate ranges compared to groups that had high scores on the DFS. There was a statistically significant difference between the groups of DFS and CPITN (p<0.05). Patients with low and moderate levels of DFS answered the oral health knowledge questions correctly. There was a statistically significant difference between the DFS groups based on correct answers to the oral health knowledge questions (p<0.05). Conclusion The elimination of dental fear is very important and should be treated according to a patient-centered assessment. These individuals were informed about the dental treatment

  14. Optical coherence tomography and confocal microscopy investigations of dental structures and restoration materials

    NASA Astrophysics Data System (ADS)

    Negrutiu, Meda L.; Sinescu, Cosmin; Rominu, Mihai; Hughes, Michael; Dobre, George; Podoleanu, Adrian G.

    2009-02-01

    Nowadays, optical tomographic techniques are of particular importance in the medical imaging field, because these techniques can provide non-invasive diagnostic images. The present study evaluates the potential of en-face optical coherence tomography (OCT) as a possible non-invasive high resolution imaging method in supplying the necessary information on the quality of dental hard tissues and defects of dental restorative materials. Teeth after several treatment methods are imaged in order to asses the material defects and micro-leakage of tooth-filling interface as well as to evaluate the quality of dental hard tissue. C-scan and B-scan OCT images as well as confocal images are acquired from a large range of samples. Cracks and voids in the dental structures as well as gaps between the dental interfaces and material defects are clearly exposed. The advantages of the OCT method consist in non-invasiveness and high resolution.

  15. [Psychometric assessment of the German version of the Index of Dental Anxiety and Fear (IDAF-4C+) - a new instrument for measuring dental anxiety].

    PubMed

    Tönnies, Sven; Mehrstedt, Mats; Fritzsche, Anja

    2014-03-01

    JM Armfield introduced the questionnaire "Index of Dental Anxiety and Fear" with the intention of giving research into this complex area a broader theoretical base. A German translation of the IDAF-4C+ was given to 287 dental patients in Germany, of which 188 were recruited from a Dental Fears Clinic. Together with the IDAF-4C+ the patients also filled out the Dental Anxiety Scale, the Dental Fear Survey and Beck's Anxiety Inventory. The good reliability of the IDAF core dental anxiety and fear module, that was found in the original Australian research, was found to be even better in the translated version. The factorial validity of the fear- and phobia module could be confirmed, the stimulus module only partly. With the translation of the IDAF-4C+ there is for the first time a questionnaire available in the German language that not only measures the extent of the dental fears but also diagnoses the anxiety-causing stimuli and intends to differentiate between dental fear and phobia.

  16. Paleovalley fills: Trunk vs. tributary

    USGS Publications Warehouse

    Kvale, E.P.; Archer, A.W.

    2007-01-01

    A late Mississippian-early Pennsylvanian eustatic sea level drop resulted in a complex lowstand drainage network being eroded across the Illinois Basin in the eastern United States. This drainage system was filled during the early part of the Pennsylvanian. Distinct differences can be recognized between the trunk and tributary paleovalley fills. Fills preserved within the trunk systems tend to be fluvially dominated and consist of bed-load deposits of coarse- to medium-grained sandstone and conglomerate. Conversely, the incised valleys of tributary systems tend to be filled with dark mudstone, thinly interbedded sandstones, and mudstones and siltstones. These finer grained facies exhibit marine influences manifested by tidal rhythmites, certain traces fossils, and macro- and microfauna. Examples of tributary and trunk systems, separated by no more than 7 km (4.3 mi) along strike, exhibit these styles of highly contrasting fills. Useful analogs for understanding this Pennsylvanian system include the Quaternary glacial sluiceways present in the lower Ohio, White, and Wabash river valleys of Indiana (United States) and the modern Amazon River (Brazil). Both the Amazon River and the Quaternary rivers of Indiana have (or had) trunk rivers that are (were) dominated by large quantities of bed load relative to their tributaries. The trunk valley systems of these analogs aggraded much more rapidly than their tributary valleys, which evolved into lakes because depositional rates along the trunk are (were) so high that the mouths of the tributaries have been dammed by bed-load deposits. These Holocene systems illustrate that sediment yields can significantly influence the nature of fill successions within incised valleys independent of rates of sea level changes or proximity to highstand coastlines. Copyright ?? 2007. The American Association of Petroleum Geologists. All rights reserved.

  17. Professional and personal enhancement: a pragmatic approach in dental education

    PubMed Central

    2016-01-01

    Purpose: Students of health education are often offended by the transitions and challenges they face while encountering diverse people, ideas and academic workloads. They may be offended because of reasons not only related to their societal background but also to their basic competence in managing transitions. In the Asian scenario, students enter the first year of professional education in their late teen age along with the definition of self which was created by their parents. There are different issues that arise in this age group that may positively shape or negatively affect the personalities of students. They need to achieve a sense of balance between personal and professional traits on their own. Several students are often unable to cultivate the expected required qualities, which leads to an abject state of mind and hinder their progress. We identified the most common personal and professional hurdles in the lives of dental students and we provided experiential solutions to overcome the hurdles by using a sociable approach through an integrated, continuing education program. Methods: Designing and implementing a cohesive, amalgamated and inspiring personal and professional enhancement action program for dental students. Results: Feedback from students reflected that the needs and expectations of students vary with academic phase. In addition students expressed that this program series inculcated some positive skills, and overall, they are satisfied with the utility of the program. Conclusion: Personal and professional enhancement of students in accordance with individual needs as well as with expected requirements needs a committed administrative action plan. Our results in this context are encouraging and can be considered for application in dental institutions. PMID:26932496

  18. Gas-Filled Capillary Model

    NASA Astrophysics Data System (ADS)

    Steinhauer, L. C.; Kimura, W. D.

    2006-11-01

    We have developed a 1-D, quasi-steady-state numerical model for a gas-filled capillary discharge that is designed to aid in selecting the optimum capillary radius in order to guide a laser beam with the required intensity through the capillary. The model also includes the option for an external solenoid B-field around the capillary, which increases the depth of the parabolic density channel in the capillary, thereby allowing for propagation of smaller laser beam waists. The model has been used to select the parameters for gas-filled capillaries to be utilized during the Staged Electron Laser Acceleration — Laser Wakefield (STELLA-LW) experiment.

  19. History of dental hygiene research.

    PubMed

    Bowen, Denise M

    2013-01-01

    Dental hygiene is defined as the science and practice of the recognition, treatment and prevention of oral diseases. The history of dental hygiene research is considered in the context of the development of the discipline and an emerging infrastructure. Research-related events supporting the growth and maturation of the profession are considered from the early years to the most recent. The benefits of preventive oral health services provided by dental hygienists have been supported by research, and the practice of dental hygiene has expanded as a result of research findings since its inception 100 years ago. Dental hygienists' engagement in research, however, did not begin until the 1960s as research associates or administrators, primarily with dental researchers as primary investigators. The Journal of Dental Hygiene (JDH) has provided information for dental hygiene practice since 1927, and has been the primary venue for dissemination of dental hygiene research since 1945. Graduate education in dental hygiene at the master's degree level and the work of early dental hygiene researchers led to the first conference on dental hygiene research in 1982. Over 30 years later, dental hygiene has established a meta-paradigm and defined conceptual models, built an initial infrastructure to support research endeavors and contributed much to the development of dental hygiene as a unique discipline. A doctoral degree in the discipline, continued theory-based research, initiatives to foster collaborations between dental hygiene and other researchers and enhanced capabilities to attract funding to support large scale studies are goals that must be attained through the efforts of future researchers to address the needs for additional development in the discipline of dental hygiene. Dental hygiene research supports the growing discipline and its value to society. PMID:24046337

  20. History of dental hygiene research.

    PubMed

    Bowen, Denise M

    2013-01-01

    Dental hygiene is defined as the science and practice of the recognition, treatment and prevention of oral diseases. The history of dental hygiene research is considered in the context of the development of the discipline and an emerging infrastructure. Research-related events supporting the growth and maturation of the profession are considered from the early years to the most recent. The benefits of preventive oral health services provided by dental hygienists have been supported by research, and the practice of dental hygiene has expanded as a result of research findings since its inception 100 years ago. Dental hygienists' engagement in research, however, did not begin until the 1960s as research associates or administrators, primarily with dental researchers as primary investigators. The Journal of Dental Hygiene (JDH) has provided information for dental hygiene practice since 1927, and has been the primary venue for dissemination of dental hygiene research since 1945. Graduate education in dental hygiene at the master's degree level and the work of early dental hygiene researchers led to the first conference on dental hygiene research in 1982. Over 30 years later, dental hygiene has established a meta-paradigm and defined conceptual models, built an initial infrastructure to support research endeavors and contributed much to the development of dental hygiene as a unique discipline. A doctoral degree in the discipline, continued theory-based research, initiatives to foster collaborations between dental hygiene and other researchers and enhanced capabilities to attract funding to support large scale studies are goals that must be attained through the efforts of future researchers to address the needs for additional development in the discipline of dental hygiene. Dental hygiene research supports the growing discipline and its value to society.

  1. Root canal filling evaluation using optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Negrutiu, Meda L.; Sinescu, Cosmin; Topala, Florin; Nica, Luminita; Ionita, Ciprian; Marcauteanu, Corina; Goguta, Luciana; Bradu, Adrian; Dobre, George; Rominu, Mihai; Podoleanu, Adrian Gh.

    2010-04-01

    Endodontic therapy consists in cleaning and shaping the root canal system, removing organic debris and sealing the intra-canal space with permanent filling materials. The purpose of this study was to evaluate various root canal fillings in order to detect material defects, the marginal adaptation at the root canal walls and to assess the quality of the apical sealing. 21 extracted single-root canal human teeth were selected for this study. We instrumented all roots using NiTi rotary instruments. All canals were enlarged with a 6% taper size 30 GT instrument, 0,5 mm from the anatomical apex. The root canals were irrigated with 5% sodium hypochlorite, followed by 17% ethylenediaminetetraacetic acid (EDTA). After the instrumentation was completed, the root canals were obturated using a thermoplasticizable polymer of polyesters. In order to assess the defects inside the filling material and the marginal fit to the root canal walls, the conebeam micro-computed tomography (CBμCT) was used first. After the CBμCT investigation, time domain optical coherence tomography working in en face mode (TDefOCT) was employed to evaluate the previous samples. The TDefOCT system was working at 1300 nm and was doubled by a confocal channel at 970 nm. The results obtained by CBμCT revealed no visible defects inside the root-canal fillings and at the interfaces with the root-canal walls. TDefOCT investigations permit to visualize a more complex stratificated structure at the interface filling material/dental hard tissue and in the apical region.

  2. Use of copper shavings to remove mercury from contaminated groundwater or wastewater by amalgamation.

    PubMed

    Huttenloch, Petra; Roehl, Karl Ernst; Czurda, Kurt

    2003-09-15

    The efficacy of copper shavings (Cu(0)) for the removal of Hg2+ from aqueous solution by amalgamation is demonstrated. Two kinds of copper shavings were investigated: (a) chemically processed shavings (Fluka) and (b) recycled shavings from scrap metal. Batch sorption experiments yielded very high retardation coefficients of 28 850-82 830 for the concentration range studied (1-10 000 microg/L Hg2+ dissolved in distilled water or in a 0.01 M CaCl2 matrix solution). Sorption data were well-described bythe Freundlich isotherm equation. Kinetic batch sorption experiments showed that 96-98% of Hg2+ was removed within 2 h. Column experiments were performed with a mercury solution containing 1000 microg/L Hg in a 0.01 M CaCl2 matrix with a flow rate of 0.5 m/d. No mercury breakthrough (c/c(0) = 0.5) could be detected after more than 2300 percolated pore volumes, and the high retardation coefficients determined in the batch studies could be confirmed. Copper was released from the shavings due to the amalgamation process and to copper corrosion by oxygen, resulting in concentrations of mobilized copper of 0.2-0.6 mg/L. Due to their high efficiency in removing Hg2+ from aqueous solution, the use of copper shavings for the removal of mercury from contaminated water is suggested, employing a sequential system of mercury amalgamation followed by the removal of mobilized copper by an ion exchanger such as zeolites. Possible applications could be in environmental technologies such as wastewater treatment or permeable reactive barriers for in situ groundwater remediation.

  3. Epidemiology of dental caries in children in the United Arab Emirates.

    PubMed

    Al-Bluwi, Ghada S M

    2014-08-01

    Dental caries has a significant impact on the general health and development of children. Understanding caries epidemiology is an essential task for the United Arab Emirates (UAE) policymakers to evaluate preventive programmes and to improve oral health. The purpose of this review is to collect and summarise all data available in the published literature on the epidemiology of dental caries in the UAE in children aged under 13 years. This will provide dental health planners with a comprehensive data summary, which will help in the planning for and evaluation of dental caries prevention programmes. Data were collected from the various published studies in PubMed, Academic Search Complete, Google, and the reference lists in relevant articles. Four keywords were used in the search: 'dental caries,' 'epidemiology,' 'prevalence,' and 'UAE'. All studies conducted in the UAE in general or any single emirate that sheds light on the prevalence of dental caries of children under 13 years were included in this literature review. Studies on early childhood caries and factors associated with dental caries were also included. The review comprises 11 published surveys of childhood caries in UAE. The earliest study was published in 1991 and the most recent was published in 2011. The range of decayed, missing and filled primary teeth (dmft) in UAE children (age between 4 years and 6 years) was 5.1-8.4. For the 12-year-old group the decayed missing and filled permanent teeth (DMFT) ranged from 1.6 to 3.24. Baseline data on oral health and a good understanding of dental caries determinants are necessary for setting appropriate goals and planning for preventive oral health programmes. The current data available on the dmft and DMFT indicate that childhood dental caries is still a serious dental public health problem in the UAE that warrants immediate attention by the government and policy makers. PMID:24860920

  4. Epidemiology of dental caries in children in the United Arab Emirates.

    PubMed

    Al-Bluwi, Ghada S M

    2014-08-01

    Dental caries has a significant impact on the general health and development of children. Understanding caries epidemiology is an essential task for the United Arab Emirates (UAE) policymakers to evaluate preventive programmes and to improve oral health. The purpose of this review is to collect and summarise all data available in the published literature on the epidemiology of dental caries in the UAE in children aged under 13 years. This will provide dental health planners with a comprehensive data summary, which will help in the planning for and evaluation of dental caries prevention programmes. Data were collected from the various published studies in PubMed, Academic Search Complete, Google, and the reference lists in relevant articles. Four keywords were used in the search: 'dental caries,' 'epidemiology,' 'prevalence,' and 'UAE'. All studies conducted in the UAE in general or any single emirate that sheds light on the prevalence of dental caries of children under 13 years were included in this literature review. Studies on early childhood caries and factors associated with dental caries were also included. The review comprises 11 published surveys of childhood caries in UAE. The earliest study was published in 1991 and the most recent was published in 2011. The range of decayed, missing and filled primary teeth (dmft) in UAE children (age between 4 years and 6 years) was 5.1-8.4. For the 12-year-old group the decayed missing and filled permanent teeth (DMFT) ranged from 1.6 to 3.24. Baseline data on oral health and a good understanding of dental caries determinants are necessary for setting appropriate goals and planning for preventive oral health programmes. The current data available on the dmft and DMFT indicate that childhood dental caries is still a serious dental public health problem in the UAE that warrants immediate attention by the government and policy makers.

  5. Prevalence of dental caries among 12–14 year old children in Qatar

    PubMed Central

    Al-Darwish, Mohammed; El Ansari, Walid; Bener, Abdulbari

    2014-01-01

    Background To ensure the oral health of a population, clinicians must deliver appropriate dental services, and local communities need to have access to dental care facilities. However, establishment of this infrastructure must be based on reliable information regarding disease prevalence and severity in the target population. Objectives The aims of this study were to measure the incidence of dental caries in school children aged 12–14 throughout Qatar, including the influence of socio-demographic factors. Materials and methods A cross-sectional study was conducted in Qatar from October 2011 to March 2012. A total of 2113 children aged 12–14 were randomly selected from 16 schools located in different geographic areas. Three calibrated examiners using World Health Organization (WHO) criteria to diagnose dental caries performed the clinical examinations. Data analyses were subsequently conducted. Results The mean decayed, missing, and filled teeth index values were respectively 4.62 (±3.2), 4.79 (±3.5), and 5.5 (±3.7), for 12, 13, and 14 year-old subjects. Caries prevalence was 85%. The mandibular incisors and canines were least affected by dental caries, while maxillary and mandibular molars exhibited the highest incidence of dental caries. Dental caries were affected by socio-demographic factors; significant differences were detected between female and male children, where more female children showed dental caries than male children. In addition, children residing in semi-urban areas showed more dental caries than in urban areas. Conclusion Results indicated that dental caries prevalence among school children in Qatar has reached critical levels, and is influenced by socio-demographic factors. The mean decayed, missing, and filled teeth values obtained in this study were the second highest detected in the Eastern Mediterranean region. PMID:25057232

  6. Structural chemistry and number theory amalgamized: crystal structure of Na11Hg52.

    PubMed

    Hornfeck, Wolfgang; Hoch, Constantin

    2015-12-01

    The recently elucidated crystal structure of the technologically important amalgam Na11Hg52 is described by means of a method employing some fundamental concept of number theory, namely modular arithmetical (congruence) relations observed between a slightly idealized set of atomic coordinates. In combination with well known ideas from group theory, regarding lattice-sublattice transformations, these allow for a deeper mutual understanding of both and provide the structural chemist with a slightly different kind of spectacles, thus enabling a distinct viw on complex crystal structures in general.

  7. Bulimia and Anorexia Nervosa in Dental and Dental Hygiene Curricula.

    ERIC Educational Resources Information Center

    Gross, Karen B. W.; And Others

    1990-01-01

    Dentists and dental hygienists are in a unique position to identify an eating disorder patient from observed oral manifestations and to refer the patient for psychological therapy. The inclusion of information on general and oral complications of bulimia and anorexia nervosa in dental and dental hygiene curriculum was examined. (MLW)

  8. Dental practice network of U.S. dental schools.

    PubMed

    Fisher, Monica A; Beeson, Dennis C; Hans, Mark G

    2009-12-01

    As dental schools incorporate training in evidence-based dentistry (EBD) into their curricula, students must learn how to critically evaluate systematic reviews and meta-analyses. It is important that dental education in the United States support the American Dental Association's position statement on EBD, which defines "best evidence" as data obtained from all study designs. Given that much evidence is missing when EBD is derived from Cochrane Systematic Reviews' randomized clinical trials, we propose the creation of a dental practice network of U.S. dental schools. We developed an electronic clinical dentistry research database for EBD using Epi-Info (available at www.cdc.gov/epiinfo/downloads.htm). As a free, public use software, Epi-Info provides the foundation for the development of clinical research databases that can increase the research capacity through multisite studies designed to generate outcomes data on the effectiveness of dental treatment. The creation of a dental practice network of dental schools with their large number of patients would expand the research capacity for EBD practice and advance the EBD science regarding the effectiveness of dental treatment. The next step is to link clinical dental researchers/educators at multiple dental schools through a collaborative clinical research network, so that the findings can be applied to the EBD component of problem-based learning curricula of dental education.

  9. Dental Implantology in U.S. Dental Schools.

    ERIC Educational Resources Information Center

    Bavitz, J. Bruce

    1990-01-01

    The results of a survey of 44 dental schools corroborate the belief that dental implantology is gaining widespread acceptance in U.S. dental schools. Currently, predoctoral students have limited clinical participation. Most programs have taken the position that clinical techniques are best taught within the existing specialties at a graduate…

  10. Correlation of dental health behavior with health awareness and subjective symptoms in a rural population in Japan.

    PubMed

    Song, Wenqun; Tamaki, Yoh; Arakawa, Yuki; Ogino, Daisuke; Aoki, Kunie; Ohyama, Masakazu; He, Dawei; Osawa, Taeko; Ohsawa, Kazuo; Kadoma, Yoshinori; Nomura, Yoshiaki; Arakawa, Hirohisa

    2014-05-01

    The aim of this study was to determine the association of dental health behavior with health awareness, oral condition, and subjective symptoms in Japan. The present study included 1699 individuals who underwent dental checkups at the public health center of Miura City. All those who underwent dental checkups were asked to fill out a questionnaire. The correlation between having a regular dentist and each of the other items was analyzed. Undergoing regular checkups was significantly related to having a regular dentist. To analyze the correlation of dental health behavior with Subjective symptoms and Health awareness, structured equation modeling was performed following factor analysis. As a result, only the regression weight between dental health behavior and health awareness was found to be statistically significant. The present survey indicates that dental health behavior was significantly related to Health awareness but not to Subjective symptoms.

  11. Curriculum Guidelines foe Dental Nutrition.

    ERIC Educational Resources Information Center

    Journal of Dental Education, 1989

    1989-01-01

    The American Association of Dental Schools' curriculum guidelines for dental nutrition include an overview of the curriculum, primary educational objectives, suggested prerequisites, a core content outline, and suggestions for sequencing and faculty qualifications. (MSE)

  12. Dental Health and Orthodontic Problems

    MedlinePlus

    ... Text Size Email Print Share Dental Health and Orthodontic Problems Page Content Article Body Dental Health Twin ... color can be tinted to match the teeth. Orthodontic Problems Crooked teeth, overbites and underbites are best ...

  13. A self-designed instrument to evaluate cavosurface angle for class I amalgam cavity preparation: A learning aid.

    PubMed

    Arora, Ankit; Acharya, Shashi Rashmi; Ballal, Vasudev; Sharma, Padmaja

    2012-07-01

    Fighting the controversies, amalgam, as a posterior restorative material has survived till date. The fate of amalgam restoration is determined by geometry of the cavity preparation and cavosurface angle is one integral part of the cavity, which decides the marginal characteristics of the restoration and health of the tooth. Low edge strength of amalgam highlights the importance of cavosurface angle. However, at the same time conservation of the tooth also should be considered. This article presents a self-designed instrument to evaluate and obtain a cavosurface angle close to 110°. The design of the instrument also helps in evaluating parameters, such as depth of the cavity, undercut angle, and allows finishing of the buccal or lingual walls.

  14. How is the ocean filled?

    NASA Astrophysics Data System (ADS)

    Gebbie, Geoffrey; Huybers, Peter

    2011-03-01

    The ocean surface rapidly exchanges heat, freshwater, and gases with the atmosphere, but once water sinks into the ocean interior, the inherited properties of seawater are closely conserved. Previous water-mass decompositions have described the oceanic interior as being filled by just a few different property combinations, or water masses. Here we apply a new inversion technique to climatological tracer distributions to find the pathways by which the ocean is filled from over 10,000 surface regions, based on the discretization of the ocean surface at 2° by 2° resolution. The volume of water originating from each surface location is quantified in a global framework, and can be summarized by the estimate that 15% of the surface area fills 85% of the ocean interior volume. Ranked from largest to smallest, the volume contributions scaled by surface area follow a power-law distribution with an exponent of -1.09 ± 0.03 that appears indicative of the advective-diffusive filling characteristics of the ocean circulation, as demonstrated using a simple model. This work quantifies the connection between the surface and interior ocean, allowing insight into ocean composition, atmosphere-ocean interaction, and the transient response of the ocean to a changing climate.

  15. Can-Filled Crash Barrier

    NASA Technical Reports Server (NTRS)

    Wilson, A. H.

    1983-01-01

    Crash barrier composed largely of used aluminum beverage cans protects occupants of cars in collisions with poles or trees. Lightweight, can-filled barrier very effective in softening impact of an automobile in head-on and off-angle collisions. Preliminary results indicate barrier is effective in collisions up to 40 mi/h (64 km/h).

  16. Space-filling polyhedral sorbents

    DOEpatents

    Haaland, Peter

    2016-06-21

    Solid sorbents, systems, and methods for pumping, storage, and purification of gases are disclosed. They derive from the dynamics of porous and free convection for specific gas/sorbent combinations and use space filling polyhedral microliths with facial aplanarities to produce sorbent arrays with interpenetrating interstitial manifolds of voids.

  17. Brain Responses to Filled Gaps

    ERIC Educational Resources Information Center

    Hestvik, Arild; Maxfield, Nathan; Schwartz, Richard G.; Shafer, Valerie

    2007-01-01

    An unresolved issue in the study of sentence comprehension is whether the process of gap-filling is mediated by the construction of empty categories (traces), or whether the parser relates fillers directly to the associated verb's argument structure. We conducted an event-related potentials (ERP) study that used the violation paradigm to examine…

  18. IMPACT OF FLUORIDE ON DENTAL HEALTH QUALITY

    PubMed Central

    Medjedovic, Eida; Medjedovic, Senad; Deljo, Dervis; Sukalo, Aziz

    2015-01-01

    Introduction: Fluoride is natural element that strengthens teeth and prevents their decay. Experts believe that the best way to prevent cavities is the use of fluoride from multiple sources. Studies even show that in some cases, fluoride can stop already started damage of the teeth. In children younger than 6 years fluoride is incorporated into the enamel of permanent teeth, making the teeth more resistant to the action of bacterial and acids in food. Goal: The aim of this study is to determine the effects of improving the health status of teeth after six months treatment with the use of topical fluoridation 0.5% NaF, and the level and quality of the impact of treatment with chemical 0.5% NaF on the dental health of children at age from 8 to 15 years, in relation to gender and chronological age. This study included school children aged 8 to 15 years who visited health and dental services dependent in Mostar. Results: It is obvious that after the implementation of treatment with 5% NaF by the method of topical fluoridation, health status of subjects from the experimental group significantly improved, so that at the final review 89.71% or 61 subjects of the experimental group had healthy (cured teeth), tooth with dental caries only 5.88% or 4 respondents tooth with dental caries and filling 4.41% or 3 respondents, extracted baby tooth 14.71% or 10 respondents, while for 13.24% of respondents was identified state with still unerupted teeth. Our findings are indirectly confirmed that the six-month treatment of fluoridation with 5% NaF, contributed to statistically significant improvement in overall oral health of the experimental group compared to the control group which was not treated by any dental treatment. Conclusion: It can be concluded that there is a statistically significant difference in the evaluated parameters of oral health of children in the control group compared to the studied parameters of oral health the experimental group of children at the final

  19. Maintaining proper dental records.

    PubMed

    Leeuw, Wilhemina

    2014-01-01

    Referred to as Standard of Care, the legal duty of a dentist requires exercising the degree of skill and care that would be exhibited by other prudent dentists faced with the same patient-care situation. Primarily, the goal of keeping good dental records is to maintain continuity of care. Diligent and complete documentation and charting procedures are essential to fulfilling the Standard of Care. Secondly, because dental records are considered legal documents they help protect the interest of the dentist and/or the patient by establishing the details of the services rendered. Patients today are better educated and more assertive than ever before and dentists must be equipped to protect themselves against malpractice claims. Every record component must be handled as if it could be summoned to a court room and scrutinized by an attorney, judge or jury. Complete, accurate, objective and honest entries in a patient record are the only way to defend against any clinical and/or legal problems that might arise. Most medical and dental malpractice claims arise from an unfavorable interaction with the dentist and not from a poor treatment outcome. By implementing the suggestions mentioned in this course, dental health care professionals can minimize the legal risks associated with the delivery of dental care to promote greater understanding for patients of their rights and privileges to their complete record. PMID:24834675

  20. Dental ethics and emotional intelligence.

    PubMed

    Rosenblum, Alvin B; Wolf, Steve

    2014-01-01

    Dental ethics is often taught, viewed, and conducted as an intell enterprise, uninformed by other noncognitive factors. Emotional intelligence (EQ) is defined distinguished from the cognitive intelligence measured by Intelligence Quotient (IQ). This essay recommends more inclusion of emotional, noncognitive input to the ethical decision process in dental education and dental practice.