Objectives: Plaque and stains are removed by prophylaxis methods from tooth surfaces. Since prophylaxis methods can have a detrimental effect on the surface finish of restorations, the aim of this in vitro study was to investigate the effect of three prophylaxis methods, including pumice with rubber cup, pumice with brush, and air-powder polishing device (APD) on the surface roughness of giomer. Study design: Sixty four cylindrical giomer (Beautifil II, Shofu) samples with a diameter of 6 mm and a height of 2 mm were used. Subsequent to a 3-month period of storage in distilled water at 37ºC, the samples were randomly divided into four groups of 16. In group 1 (control), no prophylaxis procedure was carried out. In groups 2 to 4 the samples were exposed to pumice with rubber cup, pumice with brush, and APD prophylaxis methods, respectively. The surface roughness of the samples was measured using a profilometer and the effect of different prophylaxis methods on surface topography was characterized by atomic force microscopy (AFM). All data were analyzed by one-way ANOVA and Duncan's post hoc test at a significance level of P < 0.05. Results: There were statistically significant differences in surface roughness among the groups (P < 0.0005). Furthermore, in pairwise comparisons there were statistically significant differences between all the groups (P < 0.05). The roughest surfaces, in descending order, were observed with the use of APD, pumice with brush, and pumice with rubber cup. Conclusions: The use of different prophylaxis methods resulted in an increased surface roughness of giomer compared with the control group. APD prophylaxis exerted the most detrimental effects on the surface of giomer.

BackgroundConsidering the differences in the filler particles between giomer and conventional composite resins and the importance of these fillers in the repair bond strength, the aim was to evaluate the effects of different etching strategies with phosphoric acid (PA) and hydrofluoric acid (HF) on the microtensile repair bond strength (µTRBS) of giomer.Material and MethodsTen giomer blocks were randomly assigned into 10: 1) control; 2) 37%PA-20s; 3) 3%HF-20s; 4) 3%HF-120s; 5) 9.6%HF-20s; 6) 9.6%HF-120s; 7) 37%PA-20s + 3%HF-120s; 8) 37%PA-20s + 9.6%HF-120s; 9) 3%HF-120s + 37%PA-20s; 10) 9.6%HF-120s + 37%PA-20s. In all groups, the One-Step Plus bonding system was applied and the new giomer block was bonded to the existing giomer. After cross-sectional cutting, 18 samples were prepared from each block and the µTRBS of the samples was measured at a strain rate of 0.5 mm/min. Data were analyzed with one-way ANOVA and post hoc Tukey tests (P<0.05).ResultsThe µTRBS in groups 4, 5, 6, 7, 8 and 10 were significantly higher than that in the control group (P<0.05). The µTRBS in group 2 was even less than that in the control group (P<0.001). The highest µTRBS was recorded in group 10, which was significantly different from those in groups 3, 4 and 9 (P<0.05). In addition, the differences between group 9 and groups 6, 7 and 8 were significantly different (P<0.05).ConclusionsEtching with PA resulted in a decrease in µTRBS. Etching with HF, except for 3%HF-20s and HF after etching with PA, resulted in a significant increase in giomer`s µTRBS. An increase in the application time of 3%HF resulted in a significant increase in the µTRBS. Key words:Dental restoration repair, Hydrofluoric acid, Phosphoric acid, etching.

Introduction: Adhesion of bacteria, especially Streptococcus mutans (S. mutans) , to the surface of tooth restorations is a factor in the etiology of secondary caries. Given the ever-increasing popularity of bleaching procedures, the aim of the present study was to evaluate adhesion of S. mutans and surface roughness (SR) of microhybrid composite resin and giomer subsequent to the application of 15% carbamide peroxide.

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