In Vitro Evaluation of Gastric Acid and Toothbrushing Effect on the Surface State of Different Types of Composite Resins

Abstract

Background and Objectives: The aim of this in vitro study was to evaluate the effect of gastric acid associated with the effect of toothbrushing on the surface roughness of different types of composite resin used for direct restorations. Materials and Methods: The materials used in this study were two microhybrid (Filtek Z250, Herculite XRV) and two nanohybrid (Filtek Z550, Herculite XRV Ultra) composite resins. Two hundred and forty cylindrical samples with a height of 2 mm and a diameter of 6 mm were divided into four groups (groups A, B, C and D) corresponding to each tested material (n = 60). Each group was divided in two subgroups: subgroup I—the samples were submersed in hydrochloric acid and immediately submitted to toothbrushing; subgroup II—the samples were submitted only to toothbrushing. The simulation of the acid attack was performed by immersing the samples in a 0.01 M hydrochloric acid solution for 90 min. This procedure was followed immediately by toothbrushing simulation with 10,000 cycles. The acid attack and toothbrushing simulation were performed for two times. The surface roughness evaluation was performed with a Proscan 2100 profilometer. Repeated Measures ANOVA and Bonferroni post-hoc tests were used to perform the statistical analysis. Results: Simulation of one year of toothbrushing associated or not to hydrochloric acid exposure increases the surface roughness of microhybrid and nanohybrid composite resins. Six months of toothbrushing associated to six months of hydrochloric acid exposure increase the surface roughness of nanohybrid composite resins. Conclusions: Microhybrid composite resins surface becomes rougher after toothbrush and acid submersion when comparing to nanohybrid composite resins.

Analysis of Physical and Mechanical Properties of Universal Composites under Different Types of Polishing before and after Acid Challenge

“…A study showed that acid alone without the association of brushing abrasion did not change the roughness of the composites studied. The authors observed that toothbrushing for 1 year increased the surface roughness of all the samples when compared to the samples that were exclusively finished and polished or submersed in hydrochloric acid [47].…”

One step polishing to compare the mean surface roughness of nanohybrid and microhybrid composite resins

“…The study's inclusion requirements called for sound acrylic blocks with dimensions of 2 mm by 3 mm by 3 mm and composition resins that were specified. 6 While specimens that were fractured or porous were not included for the investigation. A single increment of composite resin was applied, followed by the application of another mylar strip, a glass slide, and one more mylar strip.…”

“…The outcomes were evaluated and charted in a predesigned proforma. 6 SPSS version 27.0 was used for the statistical analysis of the data that had been gathered. "Ra" is the major quantitative result variable we are interested in.…”

“…Restorations are polished in a single stage to a high shine. 6 This study's goal was to compare the mean surface roughness of nano hybrid and micro hybrid composites using a one-step polishing method. This comparison was made based on the idea that a material with reduced surface roughness will exhibit superior perishability, aesthetics, surface & optical properties, which means less wear, less staining, low plaque, and low caries rate.…”