The aim of this in vitro study was to evaluate the effect of erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser pretreatment alone, or associated with acid etching, on the quality of marginal integrity (microleakage and marginal gap) of a resin-based fissure sealant in primary teeth. Fifty sound primary molar teeth were randomly assigned to one of five study groups, pretreated as follows: (1) 35% orthophosphoric acid etching; (2) 2.5 W laser etching; (3) 3.5 W laser etching; (4) 2.5 W laser + 35% orthophosphoric acid etching; (5) 3.5 W laser + 35% orthophosphoric acid etching. After surface pretreatment, a resin-based sealant (ClinPro) was applied to the fissures. Sample teeth were then subjected to thermocycling and stored thereafter in distilled water at 37 degrees C for 1 month. Following immersion in 0.5% basic fuchsin solution for 24 h, three bucco-lingual slices of each sample tooth were scored under a stereo-microscope. Statistical analysis was performed with Kruskal-Wallis one-way analysis of variance (ANOVA) and Pearson chi-square tests. The level of significance was set at P < 0.05. Microleakage scores of group 1 were significantly less than those of groups 2 and 3 (P < 0.05), whereas no statistically significant difference was observed between groups 1, 4 and 5 (P > 0.05). In terms of marginal gap formation, no significant difference was observed between groups (P > 0.05). It was concluded that Er,Cr:YSGG laser etching did not eliminate the need for acid etching. When combined with acid etching, Er,Cr:YSGG laser seems to be as effective as conventional acid etching.
Aim: The aim of this study was to compare the flexural and compressive strengths of a new sonicactivated bulk-fill system (Sonicfill) with other bulk-fill resins and a universal posterior composite resin. Materials and Methods: A low-stress flowable base resin material (SDR), a bulk-fill composite resin (Tetric Evo Ceram), a universal posterior composite (GC G-aenial), and the Sonicfill system were compared. The specimens were prepared for each group following ISO Standard 4049 (flexural strength) and ADA 27 specifications (compressive strength). One-way variance analysis and Kruskal-Wallis tests were used to determine the statistical differences among groups (p < 0.05). Results: The Sonicfill system presented significantly higher compressive strength than other groups (p < 0.001). For flexural strength results, although the Sonicfill system showed the highest values, no statistically significant differences were determined among all groups (p > 0.001). Conclusion: Due to the ability to place restorations with single increment and ease of use, the Sonicfill system can be an alternative for posterior restorations.
Objective: To evaluate the antibacterial activity of gaseous ozone and chlorhexidine solution on a tooth cavity model.
Study Design: Twenty-one human molars were divided into 3 groups. Cavities were then cut into the teeth (4 per tooth, 28 cavities per group). After sterilization, the teeth were left in broth cultures of 106 colony-forming units (CFU) ml-1 of Streptococcus mutans (S. mutans) at 36°C for 48 h. The appropriate treatment followed (group A, control; group B, 2% chlorhexidine solution; and group C, 80s of treatment with ozone, and the cavities were then filled with composite resin. After 72h, the restorations were removed, dentin chips were collected with an excavator, and the total number of microorganisms was determined.
Results: Both of the treatments significantly reduced the number of S. mutans present compared with the control group and there was a significant difference between the all groups in terms of the amount of the microorganisms grown (p < 0.05). Group B was beter than group C; and group C was better than group A. Moreover, it was found that the amount of the growth in the group of chlorhexidine was significantly less than that of the ozone group (p < 0.05).
Conclusion: Chlorhexidine solution was the antibacterial treatment most efficacious on S. mutans; however, ozone application could be an anlternative cavity disinfection method because of ozone’s cavity disinfection activity.
Key words:Antibacterial activity, chlorhexidine, ozone, streptococcus mutans, tooth cavity.
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