Degree of surface roughness of three restorative materials in pediatric dentistry subjected to thermocycling: in vitro study

Abstract

Objective: To assess in vitro the surface roughness of a resin modified glass ionomer (RMGI), nanohybrid resin and a bioactive composite using a roughness tester before and after the accelerated aging process by thermocycling. Materials and methods: in vitro experimental study, 20 test bodies of each biomaterial (Filtek Z250, ACTIVA Bioactive and Fuji II) were made, divided into 6 groups (3 with thermocycling - 3 without thermocycling), they were stored in distilled water at 37 ºC for 24 hours. Half of the samples from each group were subjected to thermocycling until completing 10,000 cycles at 5º C and 55º C to simulate aging in the oral cavity for one year, all samples underwent a roughness analysis with a roughness tester in four positions. Statistical analysis was performed using Stata-14 software. For comparison between the three groups, an ANOVA test was used for parametric values ​​and a Kruskal-Wallis test for non-parametric values. For individual comparisons between the groups, a Student t-test was used for parametric values ​​and a Mann-Whitney U test for non-parametric values. Results: before thermocycling, the resin had an average value of 0.49 µm, the bioactive composite 0.36 µm and the RMGI 0.49 µm. After thermocycling, the resin had an average value of 0.44 µm, the bioactive composite 0.34 µm and the RMGI 0.36 µm. Conclusion: the three restorative materials showed no statistical differences before and after thermocycling, showing a similar degree of roughness and clinically acceptable at 10,000 cycles.