The Assessment of the Abrasiveness for Resin Composite Finishing & Polishing Systems

Abstract

Objective: This in vitro study was aimed to assess the abrasiveness of 4 different composite finishing and polishing systems, on two different nano-hybrid composite materials.
 Methods: 40 composite disc samples were prepared 4 mm in diameter and 2 mm in thickness for each nano-hybrid resin composite (Tetric EvoCeram BulkFill A1 body and IPS Empress Direct A1; Ivoclar Vivadent, Schaan, Lichtenstein; n=80 in total). Each composite group was divided into 4 finishing and polishing system subgroups (Sof-Lex Disc, 3M, St. Paul MN, USA; Enhance&Pogo, Dentsply Sirona, Konstanz, Germany; OptraGloss, Ivoclar Vivadent, Shaan, Lichtenstein; Twist Dia, Kuraray Noritake, Tokyo, Japan; n=10 for each subgroup). Single surface of each sample was roughened with 600 and 800 grit sandpapers (Carbimet, Special Silicone Carbide Grinding Paper, IL, USA), respectively. Initial thickness (t1) was measured for each sample with a digital micrometer (BMI 770150, Germany). Then, 4 different finishing&polishing systems were preformed for one side of the samples, at 10 000 rpm, in dry conditions, by a single operator (30 s for a single materal). Final thicknesses (t2) were measured after finishing&polishing procedures. Statistical analyses were performed regarding t2-t1 values. Two-way Anova test was used to assess the level of abrasion for the composite and finishing&polishing materials. Tukey HSD was used for multiple comparisons.
 Results: In terms of composite materials, IPS Empress Direct presented significantly a greater level of abrasion (52.85 ± 42.26B) than Tetric Evo Ceram Bulk Fill (p < 0.001). In terms of finishing & polishing materials, significantly a greater level of abrasiveness was observed for Sof-Lex Disc (91.25 ± 47.22b) among all (p < 0.001). There was no significant differences in abrasiveness, between Enhance&Pogo - Optragloss (p = 0.859), Enhance&Pogo - Twist Dia (p = 0. 891), and Twist Dia – Optragloss (p = 0.440).
 Conclusion: Both the type of composite and the finishing & polishing material were considered effective factors for abrasion. The greatest level of abrasiveness was observed for the 4-step Sof-Lex Disc system (91 µm on average), for the total 120 seconds of application. The abrasiveness for the 2-step systems was similar and ranged between 24 – 36 µm on average, for 60 seconds of application. IPS Empress Direct presented a greater level of abrasion than Tetric Evo Ceram Bulk Fill on equal terms of finishing & polishing.