Abstract
Aim: To evaluate the influence of finishing and polishing techniques on the surface roughness of two composite resins (CRs) subjected to bleaching procedure. Methods: Forty-eight CR specimens were divided into six groups (n=8). For G1 to G3, a microhybrid CR (Opallis; FGM) was used, and G4 to G6, received a nanohybrid CR (Brilliant NewLine; Coltene/Whaledent). All specimens were subjected to bleaching procedure with 35% hydrogen peroxide (two 45-min applications, with a 5-day interval). The surface roughness of all specimens was evaluated before and after the bleaching and/or finishing/polishing (Ra parameter) by a roughness meter. After bleaching, the groups were subjected to finishing and polishing procedures: G2 and G5 - felt discs + diamond pastes; and G3 and G6 - silicon rubber tips. The control groups (G1 and G4) had no finishing or polishing treatment after bleaching. Data were analyzed by ANOVA and Tukey’s posttest, and t test for paired samples (α=0.05). Results: bleaching treatment increased Ra values for the nanohybrid CR specimens, but both finishing/polishing techniques were able to reduce these values; for the microhybrid specimens, only finishing/polishing with silicon rubber tips decreased the roughness values. Conclusions: For both microhybrid and nanohybrid CRs, the silicon rubber tips were effective to reduce the surface roughness after bleaching procedure.
Highlights
Received for publication: May 08, 2014 Accepted: June 11, 2014Braz J Oral Sci. 13(2):[158-162]The beauty of the smile is extremely important in daily life
Mean values and standard deviation of Initial Roughness (IR) and Final Roughness (FR) roughness for MHCR and NHCR are shown in Tables 2 and 3, respectively
Comparing IR and FR from G4, it was observed that the bleaching procedure significantly increased the roughness values for NHCR (p=0.0036)
Summary
Received for publication: May 08, 2014 Accepted: June 11, 2014Braz J Oral Sci. 13(2):[158-162]The beauty of the smile is extremely important in daily life. With aesthetics being increasingly valued, professionals use composite resins (CRs) as the first choice materials in dental offices, since these materials combine suitable mechanical properties with excellent aesthetics[1]. In dental practice, it is common to have patients whose restorations will be subjected to bleaching procedures[4]. A larger number of studies have been performed to confirm whether the bleaching agents may cause undesirable effects on dental tissues[5,6] and restorations[4,7,8,9,10,11]. It is important that dentists understand the consequences of these procedures on restorations’ longevity, and to substitute[8] or to maintain[4] the CRs after bleaching, whenever required
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