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Concept: Dental restoration

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In 1966, the National Institute of Dental Research (NIDR) began planning a targeted research program to identify interventions for widespread application to eradicate dental caries (tooth decay) within a decade. In 1971, the NIDR launched the National Caries Program (NCP). The objective of this paper is to explore the sugar industry’s interaction with the NIDR to alter the research priorities of the NIDR NCP.

Concepts: Lactic acid, Teeth, Dental caries, Tooth enamel, Sucrose, Oral hygiene, Dental restoration, Dental drill

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The potential adverse health effects of mercury from amalgam and bisphenol A (BPA) from composite resin have been significant concerns. It is unclear whether dental restorative materials significantly contribute to mercury or BPA levels. The purpose of this study is to use NHANES data including 14,703 subjects (2003-2004: n=7514; 2011-2012: n=7189) to examine the association between Dental Surface Restorations (DSR) and blood total mercury (THg), inorganic mercury (IHg), methyl mercury (MeHg) and urinary BPA through the stratification of covariates and multivariate analysis. Subjects were divided into three groups based on the number of dental surface restorations (DSRs, 0, 1-8, >8). Blood THg and IHg in 2003-2004 were significantly higher in the subjects with DSR (geometric mean of 0.48, 0.69 and 1.17μg/l for THg; 0.32, 0.33 and 0.39μg/l for IHg with DSR 0, 1-8 and >8). Similarly, increases of THg, IHg and MeHg were also observed in 2013-2014 (geometric mean of 0.51, 0.69 and 0.99μg/l for THg; 0.40, 0.49 and 0.66μg/l for MeHg; 0.20, 0.22 and 0.29μg/l for IHg with DSR 0, 1-8 and >8). Linear regression model analysis revealed blood THg and IHg in 2003-2004 and THg, IHg and MeHg in 2011-2012 were quantitatively associated with the number of DSRs. A dramatic decrease in urinary BPA from 2003 to 2004-2011-2012 was observed, but no significant increase with DSRs in either period of study. In conclusion, significant increases in blood THg, IHg, and MeHg in the subjects with DSRs are confirmed in a nationally representative population, a critical step in assessing the potential risk of adverse effects from dental restorative materials, but no association between dental fillings and urinary BPA was found.

Concepts: Regression analysis, Linear regression, Bisphenol A, Mercury, Dental restoration, Mercury poisoning, Dental materials, Amalgam

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Glass polyalkenoate cements (GPCs) have previously been considered for orthopedic applications. A Zn-GPC (BT 101) was compared to commercial GPCs (Fuji IX and Ketac Molar) which have a setting chemistry analogous to BT 101. Handling properties (working, T (w) and setting, T (s) times) for BT 101 were shorter than the commercial GPCs. BT 101 also had a higher setting exotherm (S (x) -34 °C) than the commercial GPCs (29 °C). The maximum strengths for BT 101, Fuji IX, and Ketac Molar were 75, 238, and 216 MPa (compressive, σ ©), and 34, 54, and 62 MPa (biaxial flexural strengths, σ (f)), respectively. The strengths of BT 101 are more suitable for spinal applications than commercial GPCs.

Concepts: Materials science, Dental restoration, Portland cement, Cement, Physical property, T-34

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Abstract Purpose: This longitudinal clinic study evaluated the effect of a glass ionomer sealant (GIS) and a fluoride varnish (FV) in the prevention of dental decay on newly erupted permanent molars of children with and without caries experience. Materials and methods: Eighty children, aged 6-8 years, with all four newly erupted first permanent molars, were divided into two groups. Group 1 consisted of 53 children without caries experience and group 2 consisted of 27 children with dental caries experience. Permanent molars of the right side were sealed with GIS and the fluoride varnish was applied on the other two permanent first molars. Evaluation of GIS retention and the effectiveness of both materials in the prevention of dental caries were performed after 6, 12 and 18 months. Results: After 18 months, of the 299 teeth, 271 (91%) showed no caries lesions and 28 presented caries lesions (9%). Teeth sealed with GIS had more carious lesions (15) than teeth with fluoride varnish (13). Most of the teeth (70%) that presented carious lesions were in group 2. Of the 138 sealed teeth, only one showed GIS to be totally present, 95 were partially present and 42 teeth were absent. Conclusion: The caries-preventive effect was very similar between both treatments. The presence of dental caries prevailed in the children with caries experience.

Concepts: Lactic acid, Teeth, Dental caries, Oral hygiene, Dental restoration, Dental drill, Fluoride therapy, Glass ionomer cement

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Objective: To perform a literature review on the clinical and/or laboratory performance of the use of calcium hydroxide in deep cavities of primary teeth. Method and Materials: Literature in professional journals and summaries of BBO, LILACS, and MEDLINE databases (2000 to 2010) linked to the Virtual Health Library and PUBMED were searched. The search strategies used included the following descriptors: “dental caries” and “dental cavity lining” and “primary tooth”, “dental cavity lining” and “primary tooth” and “calcium hydroxide”, “dental caries” and “dental cavity lining” and “primary tooth” and “calcium hydroxide”. The abstracts were selected according to the following inclusion criteria: published between 2000 and 2010, English language, trial and/or laboratory studies or literature review, regarding the use of calcium hydroxide in deep cavities of primary teeth. The abstracts analysis was performed by two reviewers separately. Potentially relevant studies available in full were analyzed based on criteria for quality assessment and displayed on an evidence-based table. Results: After reading the abstracts (N = 39), six were selected as a basis for developing the study. Conclusion: Analysis suggests that calcium hydroxide is an interesting alternative in the control of caries lesions of primary teeth with the possibility of significantly increasing the success of indirect pulp capping; however, it should not be considered a determining factor in the success of a restorative procedure.

Concepts: Lactic acid, Teeth, Tooth development, Dental caries, Dentin, Oral hygiene, Dental restoration, Dental drill

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SUMMARY Fracture resistance of inlays and onlays may be influenced by the quantity of the dental structure removed and the restorative materials used. The purpose of this in vitro study was to evaluate the effects of two different cavity preparation designs and all-ceramic restorative materials on the fracture resistance of the tooth-restoration complex. Fifty mandibular third molar teeth were randomly divided into the following five groups: group 1: intact teeth (control); group 2: inlay preparations, lithium-disilicate glass-ceramic (IPS e.max Press, Ivoclar Vivadent AG, Schaan, Liechtenstein); group 3: inlay preparations, zirconia ceramic (ICE Zirkon, Zirkonzahn SRL, Gais, Italy); group 4: onlay preparations, lithium-disilicate glass-ceramic (IPS e.max Press); and group 5: onlay preparations, zirconia ceramic (ICE Zirkon). The inlay and onlay restorations were adhesively cemented with dual polymerizing resin cement (Variolink II, Ivoclar Vivadent AG). After thermal cycling (5° to 55°C × 5000 cycles), specimens were subjected to a compressive load until fracture at a crosshead speed of 0.5 mm/min. Statistical analyses were performed using one-way analysis of variance and Tukey HSD tests. The fracture strength values were significantly higher in the inlay group (2646.7 ± 360.4) restored with lithium-disilicate glass-ceramic than those of the onlay group (1673.6 ± 677) restored with lithium-disilicate glass-ceramic. The fracture strength values of teeth restored with inlays using zirconia ceramic (2849 ± 328) and onlays with zirconia ceramic (2796.3 ± 337.3) were similar to those of the intact teeth (2905.3 ± 398.8). In the IPS e.max Press groups, as the preparation amount was increased (from inlay to onlay preparation), the fracture resistance was decreased. In the ICE Zirkon ceramic groups, the preparation type did not affect the fracture resistance results.

Concepts: Touring car racing, FIA, Teeth, Analysis of variance, Crown, Dental restoration, CAD/CAM Dentistry, Inlays and onlays

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The association of environmental and genetic variation in caries with child externalizing behavior problems (inattention, hyperactivity, impulsivity, and defiance) was studied in a sample of 239 pairs of 3- to 8-year-old impoverished Brazilian twins. It was hypothesized that externalizing problems would show a stronger positive association with environmental than genetic variation in caries. Univariate twin models were estimated to parse variation in caries into three components: additive genetic (A), shared environment © and non-shared environment/error (E). Age-adjusted associations between externalizing problems and each variance component were tested. Contrary to the hypothesis, modest but very consistent negative associations were found between externalizing problems and both genetic and environmental variation in caries. Mutans streptococci and sweetness preference did not explain the negative associations of caries and externalizing problems. Externalizing problems in non-medicated children were associated with less dental decay that could be explained by both genetic and environmental factors. © 2014 S. Karger AG, Basel.

Concepts: Scientific method, Environment, The Association, Theory, Lactic acid, Dental caries, Dental restoration, Streptococcus mutans

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Marginal adaptation is essential for the long-term success of dental restorations. Studies comparing the marginal gaps of computer-aided design/computer-aided manufacturing (CAD/CAM) restorations made from conventional and digital impressions are limited.

Concepts: Crown, Dental restoration, Zirconium dioxide

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Aim of the study was to evaluate the long-term reliability and effectiveness of inlays and onlays in ceramic and composite material, examining scientific studies published from 2004 to 2013. The results of this review were analyzed and compared with the important literature review proposed by Manhart in 2004.

Concepts: Scientific method, Science, Composite material, Cultural studies, Dental restoration, Restorative dentistry, Inlays and onlays

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Restorative procedures are accompanied by a reduction of tooth stability, a decrease of fracture resistance, and an increase in deflection of weakened cusps. The choice between a direct or an indirect restorative technique, mainly in posterior areas, is a challenge, and involves biomechanical, anatomical, functional, esthetic, and financial considerations. In this article, the pros and cons of direct restorations are examined, as well as an analysis of indirect restorations and an overview of dental ceramics. In particular, several clinical uses of lithium disilicate overlays with a circumferential adhesive ferrule effect are proposed: heavily compromised vital teeth with thin walls, cracked teeth, and endodontically treated molars. Clinical procedures are described step by step on the basis of data from scientific literature. In conclusion, the use of lithium disilicate in combination with adhesive technologies can lead to a more conservative, economic, and esthetic approach in the restoration of heavily compromised teeth.

Concepts: Science, Teeth, Tooth, Lithium, Chess, Lithium pharmacology, Ceramic, Dental restoration