SUMMARY Objectives: The objective of this in vitro study was to compare, with a threshold value of 200 nm, the surface roughness obtained when using 12 different polishing systems on four different composite resins (microfill, nanofill, and two nanohybrids). Methods and Materials: A total of 384 convex specimens were made using Durafill VS, Filtek Supreme Ultra, Grandio SO, and Venus Pearl. After sandblasting and finishing with a medium-grit finishing disc, initial surface roughness was measured using a surface roughness tester. Specimens were polished using 12 different polishing systems: Astropol, HiLuster Plus, D♦Fine, Diacomp, ET Illustra, Sof-Lex Wheels, Sof-Lex XT discs, Super-Snap, Enhance/Pogo, Optrapol, OneGloss and ComposiPro Brush (n=8). The final surface roughness was measured, and data were analyzed using two-way analysis of variance. Pairwise comparisons were made using protected Fisher least significant difference. Results: There were statistical differences in the final surface roughness between polishing systems and between composite resins (p<0.05). The highest surface roughness was observed for all composite resins polished with OneGloss and ComposiPro Brush. Enhance/Pogo and Sof-Lex Wheels produced a mean surface roughness greater than the 200-nm threshold on Filtek Supreme Ultra, Grandio SO, and Venus Pearl. Data showed that there was an interaction between the composite resins and the polishing systems. Conclusions: A single polishing system does not perform equally with all composite resins. Except for Optrapol, multi-step polishing systems performed generally better than one-step systems. Excluding Enhance/Pogo, diamond-impregnated polishers led to lower surface roughness. Durafill VS, a microfill composite resin, may be polished more predictably with different polishers.

The results obtained from this in vitro study suggest that polishing direction influences the marginal adaptation of composite resins and that polishing from composite resin to tooth structure should be clinically performed whenever possible on accessible margins to preserve marginal integrity and esthetics.

Study Objectives: Obstructive sleep apnea (OSA) is a sleep-related disorder with high prevalence in our society. The gold standard for the treatment of sleep apnea is continuous positive airway pressure (CPAP). Given the low adherence rate of patients on CPAP treatment, interest has turned toward dental appliances, commonly called mandibular advancement devices (MAD). The aim of this study was to determine whether patients' maximum protrusion could be increased after wearing a MAD for 3 months, such that patients with weak protrusion (who could at first be withdrawn from treatment) could be eligible for this treatment. Methods:The experimental group included 30 patients in whom OSA was diagnosed by polysomnography. Patients were matched with 30 healthy control patients without OSA. The experimental group wore a MAD for 90 days whereas the control group received no treatment. Both groups underwent two assessments of mandibular borderline movements (protrusion, maximum opening, and left and right lateral movement) at baseline and after 90 days with computerized mandibular scanning.Results: Results showed that wearing the MAD did not cause greater changes in mandibular movements compared to controls. However, in the MAD group, maximum opening decreased, lateral movement increased, and maximum protrusion increased. Patients with weak maximum protrusion at baseline showed increased maximum protrusion.Conclusions: Further studies are needed to assess changes in maximum protrusion in patients with weak maximum protrusion. Nevertheless, the findings provide a deeper understanding of the effects of MAD wear on jaw movements, and indicate the potential of the MAD as an effective therapy for patients with maximum protrusion less than 5 mm.

for believing in me and giving me the opportunity to fulfill my professional goal. Finally, I thank the faculty, the staff and my precious classmates in the Department of Operative Dentistry and the Department of Family Dentistry at the University of Iowa. You are all truly wonderful.

Introduction: Adhesive formulation may affect the marginal adaptation of composite resin restorations. Objectives: To evaluate the effect of adhesive filler content on the gingival marginal adaptation of Class II composite resin restorations. Materials and methods: Class II cavity preparations were made in ninety intact extracted human molars. Specimens were randomized and equally distributed in 6 groups (n = 15). Preparations were etched and All-Bond 3 primers A + B (Bisco, Schaumburg, IL/USA) were applied. One group received All-Bond 3 adhesive/resin (50 wt% filler) and the other five groups received the same resin composition but with filler contents of 0, 10, 20, 30 and 40 wt%. Teeth were restored with Filtek Supreme Ultra (3M, St-Paul, MN/USA), finished and stored in artificial saliva (37°C/24 h) before replicas were made for FE-SEM observation (200X). Quantitative margin analysis was performed based on a four criteria: MQ1 (continuous margin), MQ2 (marginal irregularities, porosities, roughness, no gap), MQ3 (small gaps of up to 2 microns) and MQ4 (severe gaps). Data were analyzed with a one-way ANOVA based on ranked data followed by the post-hoc Bonferroni test. Results: There was no statistically significant difference in "continuous margin" observed among the six filler contents (p = 0.0886). However, significantly less severe gaps were obtained with filler levels of 30 wt% and 40 wt% compared to 0 wt% (p = 0.0159). A noticeable but non-significant difference was observed for the unfilled adhesive (0 wt%), which showed the lowest mean % for continuous margins and the highest for severe gaps. Conclusion: Filler addition to adhesive appears to improve the marginal adaptation. Filler contents of 30 wt% and 40 wt% significantly reduced the occurrence of severe gaps compared to 0 wt%.

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