A high-intensity LED LCU used for 10 seconds resulted in RH values greater than 80%, with all four restoratives tested indicating a sufficient degree of monomer conversion with such a short curing cycle.

Objectives: To assess the prevalence and severity of dental caries amongst Egyptian adolescents and the prevalence of carious lesions treatable through the atraumatic restorative treatment (ART) approach. Subjects and Methods: Using a convenient sample procedure, two secondary schools with a dental clinic were selected (967 students, average age: 13.7 ± 0.8 years, range: 12–15). Dental caries was diagnosed using the ART caries criteria, and plaque and calculus were assessed using the Green and Vermillion criteria amongst students grades 1–3 in the dental clinic by 3 calibrated examiners. The effect of the independent variables gender, age, tooth surface, jaw side (left or right) and type of jaw (mandible/maxilla) on dependent caries experience variables and D₂ and D₃ variables were tested using ANOVA. Results: The prevalence of dental caries including enamel lesion (D₂MFT) amongst the 967 students was 51.4% and that of dental caries excluding enamel lesions (D₃MFT) was 38.1%. The mean D₂MFT and D₃MFT scores were 1.5 and 0.8, respectively. The percentage of teeth filled and extracted was low. Female students had statistically significantly higher mean D₃MFT/S and D₂MFT/S scores than males (p < 0.0001). The prevalence of cavitated carious lesions (D₃) treatable through ART was 48% for score 2 and 28% for score 3. Conclusions: Most of the cavitated lesions were found untreated despite the presence of a dental clinic and a dentist on the school premises. The majority of cavitated lesions without pulp involvement could be treated using the preventive and restorative components of the ART approach.

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The effect of preheating of the silorane-based resin composite on intrapulpal temperature (IPT) and dentin microtensile bond strength (μTBS) was evaluated. For the IPT, teeth (n = 15) were sectioned to obtain discs of 0.5 mm thickness (2 discs/tooth). The discs were divided into three groups (n = 10/group) according to the temperature of the Filtek LS™ silorane-based resin composite during its placement, either at room temperature (23 ± 1 °C) or preheated to 54 °C or 68 °C using a commercial Calset™ device. Discs were subjected to a simulated intrapulpal pressure (IPP) and placed inside a specially constructed incubator adjusted at 37 °C. IPT was measured before, during and after placement and curing of the resin composite using K-type thermocouple. For μTBS testing, flat occlusal middentin surfaces (n = 24) were obtained. P90 System Adhesive was applied according to manufacturer’s instructions then Filtek LS was placed at the tested temperatures (n = 6). Restorative procedures were done while the specimens were connected to IPP simulation. IPP was maintained and the specimens were immersed in artificial saliva at 37 °C for 24 h before testing. Each specimen was sectioned into sticks (0.9 ± 0.01 mm2). The sticks (24/group) were subjected to μTBS test and their modes of failure were determined using scanning electron microscope (SEM). For both preheated groups, IPT increased equally by 1.5–2 °C upon application of the composite. After light curing, IPT increased by 4–5 °C in all tested groups. Nevertheless, the IPT of the preheated groups required a longer time to return to the baseline temperature. One-way ANOVA revealed no significant difference between the μTBS values of all groups. SEM revealed predominately mixed mode of failure. Preheating of silorane-based resin composite increased the IPT but not to the critical level and had no effect on dentin μTBS.

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Silane application is not mandatory for repairing silorane-based resin composite, which can be successfully repaired even with different repair adhesive/materials. However, early signs of nanoleakage can be detected. SUMMARYObjectives: To investigate the effect of silane primer application, intermediate adhesive agent/repair composite, and storage period on the interfacial microtensile bond strength (lTBS) of repaired silorane-based resin composite compared with unrepaired composites and on the nanoleakage.Methods: Forty-eight 1-month-old substrate specimens from Filtek P90 were roughened, etched, and distributed over two groups (n=24) based on receiving silane (Clearfil Ceramic Primer) or not. Then, half of the specimens (n=12) were repaired with P90 System Adhesive/Filtek P90 and the other half with Adper Scotchbond Multipurpose adhesive/Filtek Z250 resin composite. Within each repair category, repaired specimens were stored in artificial saliva at 378C for either 24 hours (n=6) or two years before being serially sectioned into sticks (0.6 6 0.01 mm 2 ). From each specimen, two sticks were prepared for nanoleakage determination and four sticks were used for lTBS testing. Additional unrepaired specimens from each composite (n=12) were made to determine the cohesive strength at 24 hours and two years. Mean lTBS were calculated and statistically analyzed. Modes of failure were also determined.Results: General linear model analysis revealed no significant effect for the silane priming, intermediate adhesive agent/repair composite, and storage period or for their interactions on the lTBS values of the repaired specimens. There was no significant difference between the cohesive strength of Filtek P90 and Filtek Z250; both were significantly higher

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