Zirconia-based ceramics offer strong restorations in dentistry, but the adhesive bond strength of resin cements to such ceramics is not optimal. This study evaluated the influence of surface treatments on the bond strength of resin cement to yttrium-stabilized tetragonal zirconia (Y-TZP) ceramic. Seventy-five plates of Y-TZP ceramic were randomly assigned to five groups (n = 15) according to the surface treatments [airborne particle abrasion, neodymium-doped yttrium aluminum garnet (Nd:YAG) laser irradiation (Fidelis Plus 3, Fotona; 2 W, 200 mJ, 10 Hz, with two different pulse durations 180 or 320 μs), glaze applied, and then 9.5 % hydrofluoric acid gel conditioned, control]. One specimen from each group was randomly selected, and specimens were evaluated with x-ray diffraction and SEM analysis. The resin cement (Clearfil Esthetic Cement, Kuraray) was adhered onto the zirconia surfaces with its corresponding adhesive components. Shear bond strength of each sample was measured using a universal testing machine at a crosshead speed of 1 mm/min. Bond strengths were analyzed through one-way ANOVA/Tukey tests. Surface treatments significantly modified the topography of the Y-TZP ceramic. The Nd:YAG laser-irradiated specimens resulted in both increased surface roughness and bond strength of the resin cement. The highest surface roughness and bond strength values were achieved with short pulse duration. Nd:YAG laser irradiation increased both surface roughness of Y-TZP surfaces and bond strength of resin cement to the zirconia surface.

Objective: To evaluate the dentoalveolar and skeletal effects of the new-generation open-bite appliance.

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The present study was designed to evaluate the effects of low-level laser (Nd:YAG) therapy and occlusal splints in patients with signs and symptoms of temporomandibular disorders (TMD) characterized with myofascial pain (MP). A total of 30 patients were selected after being diagnosed with MP according to the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TDM). The patients were divided into three groups. The first group was occlusal splint (OS) group A (n = 10), the second was low-level laser therapy (LLLT) group B (n = 10), and the last group C was placebo (n = 10). LLLT (1,064 nm, 8 j/cm(2), 250 mW, Fotona) was applied to the patients in the study group once a day for 10 days, for a total of ten sessions. The same parameters and application times were used for placebo group, but the patients were not irradiated. The application was on the trigger points. The patients in the OS group were instructed to wear occlusal splints 12 h/day for 3 weeks. Functional examination was based on RDC/TDM, and pressure pain values were obtained with the Visual Analog Scale. Comparisons were made between the groups before and after the treatment according to Wilcoxon, Mann-Whitney U, and Kruskal-Wallis tests. The pain score values decreased significantly after both LLLT (p < 0.05) and occlusal splint therapy (p < 0.05) compared to placebo group (p < 0.05). There was no significant difference between LLLT and OS groups after treatment (p > 0.05). OS and LLLT are effective for decreasing MP. In addition, this particular type of LLLT is as effective as occlusal splint for pain relief.

The purpose of this study was to measure intrapulpal temperature rise induced by two kinds of bleaching gels when the tooth was exposed to a variety of light-curing units and a diode laser in vitro. The root portions of 80 extracted intact human maxillary central incisors were sectioned with a carborundum disk approximately 2 mm below the cementoenamel junction perpendicular to the long axis of the teeth. Two bleaching agents containing heat-enhancing colorant was applied to the labial surface. Light-curing units used were a conventional halogen (40 s), a high-intensity halogen (30 s), a light-emitting diode unit (40 s), and a diode laser (15 s). The temperature rise was measured in the pulpal chamber with a J-type thermocouple wire that was connected to a data logger. Ten specimens were used for each system and bleaching-agent combination. Differences between the starting temperature and highest temperature reading were taken and the calculated temperature changes were averaged to determine the mean value in temperature rise. Temperature rise values were compared using two-way analysis of variance (ANOVA) at a preset alpha of 0.05. Temperature rise varied significantly depending on curing unit and diode laser used. The diode laser induced significantly higher temperature increases than any other curing unit (11.7 degrees C). The light-emitting diode unit produced the lowest temperature changes (6.0 degrees C); however, there were no statistically significant differences among the curing units and there were no statistically significant differences between bleaching agents. Light activation of bleaching materials with diode laser caused higher temperature changes as compared to other curing units and the temperature rise detected was viewed as critical for pulpal health.