Translucency parameter of conventional restorative glass-ionomer cements.

OBJECTIVE: To evaluate the translucency parameter (TP) and contrast ratio (CR) of different conventional restorative glass-ionomer cements (GICs). MATERIALS AND METHODS: Eighteen brands of GICs were evaluated. Five disks of each material were made following ISO 9917-1. The luminous reflectance and Central Bureau of the International Commission on Illumination parameters of disks were evaluated using a colorimeter, against backings of white and black, to obtain the translucent parameter and contrast ratio of different brands of glass-ionomer cements. The correlation between translucency parameter and contrast ratio was assessed with the Pearson correlation test. The translucent and contrast ratio parameters values were submitted to the one-way ANOVA and Tukey test for multiple comparisons (p < 0.05). RESULTS: There was a strong inverse relationship between CR and TP (r2 = 0.94, p < 0.001). The contrast ratio decreased as translucency increased. There were significant differences in TP and CR among brands (p < 0.001). CONLUSIONS: GICs exhibit different translucency and contrast ratio behavior. Some brands of GICs presented very low TP and this condition would be unacceptable for areas with esthetic demands. In addition, TP and CR showed a strong linear relationship. CLINICAL SIGNIFICANCE: The results found in this study demonstrated that the knowledge of the translucency and CR of different conventional restorative GICs is important in order to guide clinicians in the selection of restorative GICs for anterior teeth

Accelerating functional gene discovery in osteoarthritis

Osteoarthritis causes debilitating pain and disability, resulting in a considerable socioeconomic burden, yet no drugs are available that prevent disease onset or progression. Here, we develop, validate and use rapid-throughput imaging techniques to identify abnormal joint phenotypes in randomly selected mutant mice generated by the International Knockout Mouse Consortium. We identify 14 genes with functional involvement in osteoarthritis pathogenesis, including the homeobox gene Pitx1, and functionally characterize 6 candidate human osteoarthritis genes in mouse models. We demonstrate sensitivity of the methods by identifying age-related degenerative joint damage in wild-type mice. Finally, we phenotype previously generated mutant mice with an osteoarthritis-associated polymorphism in the Dio2 gene by CRISPR/Cas9 genome editing and demonstrate a protective role in disease onset with public health implications. We hope this expanding resource of mutant mice will accelerate functional gene discovery in osteoarthritis and offer drug discovery opportunities for this common, incapacitating chronic disease

Prostheses Removal for Suture Removal after Immediate Load: Success of Implants

Purpose: The aim of this cohort study was to evaluate the success of implants after immediate loading in cases when the prostheses were removed for suture removal on the tenth day following implant placement. We describe a technique for fabricating effective definitive prostheses passively fitted to facilitate immediate load in edentulous patients. Materials and Methods: Seventy-one patients with resin-metal prostheses installed within less than 48 hours after implant placement were recalled. Patients for whom various amounts of time had elapsed since implant placement returned for follow-up. Time elapsed ranged from 6 months to 7 years. Stability of the implants was tested after prosthesis removal by horizontal and vertical percussion tests. Implant success was determined as the number of functional implants displaying no mobility. Results: Follow-up revealed that all implants from each period evaluated were stable, with no mobility (100% of implants success), except for the 1-year time point (99.5%) and the 2-year time point (98.9%). No signs of inflammation and/or bleeding were observed. Conclusion: Prosthesis removal for suture removal on the tenth day after implant placement represents a reliable and predictable procedure that did not jeopardize implant stability during bone remodeling.12324424

Effects of resin luting agents and 1% NaOCl on the marginal fit of indirect composite restorations in primary teeth

Objective: The purpose of this study was to provide information regarding the marginal adaptation of composite resin onlays in primary teeth previously treated with 1% sodium hypochlorite (NaOCl) (pulp irrigant) using two different resin luting agents. Material and Methods: Forty extracted sound primary molars had their crowns prepared in a standardized machine and were randomly divided into 4 groups (n=10): G1 (1% NaOCl irrigation+EnForce); G2 (EnForce); G3 (1% NaOCl irrigation+Rely X); G4 (Rely X). The onlays were made with Z250 composite resin on plaster models. After luting, the tooth/restoration set was stored in 100% relative humidity at 37 degrees C for 24 h and finished with Soflex discs. Caries Detector solution was applied at the tooth/restoration interface for 5 s. The specimens were washed and four digital photos of each tooth were then taken. The extents of the gaps were measured with Image Tool 3.0 software. The percentage data were submitted to a Kruskal-Wallis test (alpha=0.05). The Relative Risk test analyzed the chance of a gap presence correlated to each group. Results: There were no statistically significant differences (p>0.05) among the groups. The relative risk test revealed that some groups were more apt to have a presence of gaps than others. Conclusion: Neither the 1% NaOCl treatment nor the resin luting agents caused any alterations in the dental substrate that could have influenced the marginal adaptation of composite onlays in primary teeth.19545546

Effect of sodium hypochlorite on primary dentin - A scanning electron microscopy (SEM) evaluation

Objective: The aim of this study was to evaluate the alterations of etched deciduous dentin when submitted to different time and concentrations of sodium hypochlorite (NaOCl), using scanning electron microscopy (SEM). Material and methods: Forty deciduous anterior teeth were selected, cleaned and ground until expose a flat dentin area on the buccal surface. The specimens were randomly distributed into eight groups (n = 5), according to dentin surface treatment (35% phosphoric acid etching for 7 s-AE and/or NaOCl application), NaOCl solution concentration (5% or 10%), and time of application (0, 30, 60, and 120 s), as follows: G1: control (without AE and NaOCl); G2: only AE; G3, G4, and G5: AE + 5% NaOCl for 30, 60, and 120 s, respectively; G6, G7, and G8: AE + 10% NaOCl for 30, 60, and 120 s, respectively. All specimens were prepared for SEM analysis and the photomicrographs (three for each specimen) were classified according to a score as follow: 0: presence of smear layer (SL); 1: absence of SL + non-altered collagen fibrils; 2: absence of SL + collagen fibrils slightly altered; 3: absence of SL + collagen fibrils severely altered; and 4: absence of SL and absence of collagen fibrils. Data were submitted to Kruskal-Wallis and Mann-Whitney tests (p < 0.05). Results: All groups treated with NaOCl solution were significant different from G1 and G2, and showed alterations on the collagen fibrils network. Collagen complete removal was only observed when a 5% NaOCI solution was applied for 120 s and 10% NaOCI solution for 30, 60, and 120 s. Conclusions: The NaOCl action produced significant changes in the etched deciduous dentin. The higher NaOCl concentration, the lower the time required to completely removing the collagen fibrils network in deciduous dentin. (c) 2005 Published by Elsevier Ltd.34745445

Compressive strength recovery by composite onlays in primary teeth. Substrate treatment and luting agent effects

Objectives: To evaluate 1% NaOCl treatment and two resin luting agent effects on compressive strength recovery in composite onlays on primary teeth and to analyze the fractures type. Methods: Forty sound primary molars crowns were prepared in the standard machine and randomly divided into four groups (n = 10): G1 (1% NaOCl/30 min + EnForce); G2 (without 1% NaOCl EnForce); G3 (1% NaOCl/30 min + Rely X); G4 (without 1% NaOCl + Rely X). The onlays were made using Z250 composite on plaster models. Ten sound teeth were used as control group (CG). All groups were submitted to compression mechanic test in a universal test machine INSTRON at 1 mm/min cross-head speed. After that, the data (kgf) were submitted to ANOVA test (alpha = 0.05). Finally, the fracture types were classified in a crescent scale (1-5) related with severity degree and submitted to Fisher's Exact Test (p 0.05). The results from fracture type showed that types 5 and 4 fractures (most severe) present the highest percentage to experimental groups. Conversely, the CG showed higher percentage of fracture types 2 and 3. Conclusions: This research found that the composite onlays recovered the compressive strength compared to sound teeth, regardless of the substrate treatment and cement agent used. Nevertheless, no group showed similar type of fractures to CG, which had more frequency of less severe fracture types. (c) 2005 Elsevier Ltd. All rights reserved.34747848

NaOCl effects on primary and permanent pulp chamber dentin

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Objectives: The dentin quality of primary and permanent pulp chamber was inspected by Fourier-transformed Raman spectroscopy (FT-Raman) and scanning electron microscopy (SEM). Fragments of pulp chamber dentin were obtained from 20 human molar crowns (primary and permanent). Methods: The fragments were assigned to 8 groups (n = 5)-Primary teeth: G1, pulp chamber dentin; G2, pulp chamber dentin irrigated with NaOCl 1% (30 min); G3, pulp chamber dentin irrigated with NaOCl 1% (30 min) and etched by 35% phosphoric acid; G4, pulp chamber dentin etched by 35% phosphoric acid. Permanent teeth: G5, pulp chamber dentin; G6, pulp chamber dentin irrigated with NaOCl 1% (30 min); G7, pulp chamber dentin irrigated with NaOCl 1% (30 min) and etched by 35% phosphoric acid; G8, pulp chamber dentin etched by 35% phosphoric acid. The spectra were subjected to the Cluster analysis. The SEM images were scored. Results: Inorganic content: There was a difference between primary and permanent dentin. The groups treated with NaOCl were statistically similar between them, but differed from the groups not treated. Organic content: There was no difference between primary and permanent dentin. The groups became similar after NaOCl and phosphoric acid treatments. The microscopic images showed the presence of calcospherites on permanent dentin and their absence on primary dentin. Conclusions: The NaOCl changed the inorganic content in both dentitions; regardless of the following phosphoric acid etching. However, the chemical changes caused by NaOCl were not detected by SEM when it was followed by etching. (C) 2008 Elsevier Ltd. All rights reserved.369745753Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESP [#05/50811-9, 01/133848

New perspectives about molecular arrangement of primary and permanent dentin

The dentin quality of primary and permanent teeth was inspected by Fourier transformed Raman spectroscopy (FT-Raman); scanning electron microscopy/energy-dispersive spectroscopy (SEM/EDS) and hardness test. Middle dentin of crowns were reached by carbide bur abrading providing a uniform smear layer. Phosphoric acid was applied in order to simulate the etching of total etching adhesive systems. The groups were (n = 10): G1 (primary dentin smear layer); G2 (35% phosphoric acid etched primary dentin); G3 (permanent dentin smear layer); G4 (35% phosphoric acid etched permanent dentin). FT-Raman results were subjected to cluster analysis. SEM/EDS were made in order to add the data obtained by FT-Raman. The hardness data were subjected to ANOVA and Tukey test. FT-Raman showed differences among groups, either to organic or inorganic content. For the organic content, primary and permanent dentin became similar after the etching; conversely, the inorganic content showed differences for the two substrates. Hardness test showed no significant differences between primary and permanent dentin, before or after etching, but the etching decreased these values. The mineral content arrangement of primary dentin is different from permanent dentin, independently of the etching. The substrate type did no influence the hardness, but the etching decreased it. (c) 2007 Elsevier B.V. All rights reserved.25451498150

Inhibition of mineral loss at the enamel/sealant interface of fissures sealed with fluoride- and non-fluoride containing dental materials in vitro

Objective. In this in vitro study we evaluated the enamel mineral loss effect of fluoride-containing and non-fluoride-containing materials at different distances from the sealant margin, and verified the fluoride-releasing capability of these materials. Material and methods. Extracted molars were randomly assigned into nine groups (n = 12): Concise (C), FluroShield (F), Helioseal Clear Chroma (H), Vitremer (V), Fuji II-LC (FII), Ketac Molar (KM), Fuji IX (FIX), Single Bond (SB), and Clearfil Protect Bond (CF). All groups were subjected to thermo and pH cycling. Enamel mineral loss was evaluated by cross-section micro-hardness analysis at distances: -100 mu m, 0 mu m, 100 mu m, 200 mu m. The mineral loss data were analyzed using a multi-factor ANOVA with split-plot design, and fluoride-released data were submitted to ANOVA and Tukey tests. Results. FIX demonstrated a lower mineral loss than C, F, and H, but did not differ from the SB, CF, V, FII, and KM groups, which also demonstrated no difference among them. C, F, H, and V presented the highest mineral loss, with no difference among them. V did not differ from the other groups (p > 0.05). Regarding the different distances from the sealant margin, -100 mu m presented the lowest mineral loss. FIX showed the highest fluoride release on the 7th and 14th days of evaluation, while CF showed high fluoride release only on the 7th day. Conclusion. Resin sealant did not prevent enamel mineral loss, contrary to glass-ionomer cement, which showed the highest capacity for fluoride release. It is not exclusively the presence of fluoride in a material's composition that indicates its capability to interfere with the development of enamel caries-like lesions.64637638