Journal of Dental Medicine

Background and Aims: Finishing and polishing of composites is a critical step influencing the clinical service of restorations. The aim of this article was to evaluate and compare the effect of two liquid polishes on the polish retention of two nanocomposites.
Materials and Methods: Eighty standardized disk-shaped specimens (4×2 mm) were prepared from two nanocomposites (n=40), including one nano-filled composite (Filtek Z350 XT-3M ESPE, USA) and one nano-hybrid composite (Aelite Aesthetic Enamel-Bisco, Inc. Schaumburg, USA). The specimens were randomly divided into 4 subgroups (n=10) based on the method of finishing (F) and polishing (P) procedures: M: as control, polymerized under Mylar strip; S: finish and polish with a sequence of Sof-Lex discs (3M ESPE, USA); SP: finish and polish with Sof-Lex discs and use of Permaseal liquid polish (Ultradent products, Inc. USA); SB: finish and polish with Sof-Lex discs and use of Biscover liquid polish (Bisco, Inc. Schaumburg, USA). The specimens were undergone pH cycling and brushing machine and then, the average surface roughness (Ra) and average profile changes along the desired area (Rz) of the specimens were determined with profilometer instrument. Two-way and one-way analysis of variance (ANOVA) was used to compare the mean of surface roughness. Then, Tukey test was used to identify the groups responsible for the difference and t-test was used to compare the mean of surface roughness.
Results: The type of composite and the method of polishing procedure had no effect on the mean Ra (P=0.733) but it had significant effect on Rz1 factor (P=0.025).
Conclusion: Using liquid polish after polishing discs had no effect on the polish retention of nanocomposites.

Background and Aims: Finding an appropriate method for polishing that can be used in dental practices to improve the longevity and ease of dental restorations is of great importance. The aim of this study was to evaluate the effect of different polishing methods on the surface roughness of two types of nano-hybrid composites, an in vitro study.
Materials and Methods: In this study, 42 samples in the form of discs (6 mm in diameter and 3 mm in thickness) of two nano-hybrid composites (Charisma Kulzer and EvoCeram Tetric IPS) were prepared. Each group had 21 samples (polymerized in a mold made of polyfluorohalide material) and were all shaded (A2 color). To prevent mirror-like reflections, each sample was covered. A 2 kg load was applied for 30 seconds on each sample, after which the composites were removed. The samples were stored for 7 days in deionized water at room temperature and in the dark. After this period, the samples underwent finishing and polishing procedures. Seven random samples from each composite group were polished using different methods: System Gloss Composite LUCIDA, EVE polishing discs, and EVE polishing discs + Cosmedent polish. The surface roughness was measured using a profilometer, and observations were made under a microscope. Data were analyzed using SPSS 25 software with t-tests, ANOVA, and the Bonferroni post hoc test.
Results: The two-stage method using EVE polishing discs showed significantly the lowest surface roughness in both types of composites (P<0.0001). The type of composite did not have a significant effect on initial surface roughness (P=0.067), but the polishing method had a significant effect on the surface roughness (P<0.0001). The difference in the mean surface roughness was statistically significant among different polishing methods for either type of composites (P<0.0001). The t-test analysis showed no significant difference in the surface roughness between the two types of composites with different polishing methods (P>0.05), except in the LUCIDA polishing system where a significant difference was observed in both groups.
Conclusion: The results showed that the polishing method had a significant effect on the surface roughness and not the type of composte. The use of EVE polishing discs effectively reduced the surface roughness in both types of nano-hybrid composites used in the present study.