Microhardness evaluation of silorane and methacrylate composites submitted to erosion and abrasion processes

Abstract

Objective: The aim of this study was to evaluate the Knoop hardness number (KHN) of methacrylate (MC) and silorane (SC) composites after being submitted to erosion and abrasion processes. Material and methods: Forty samples were made with each composite: MC and SC. The samples were divided into eight groups (n = 10) according to the type of composite (G1–G4, MC; G5–G8, SC) and the beverages involved in the erosion process (G1 and G5 – Control (C), without erosion, with abrasion; G2 and G6 – Orange Juice (OJ), abrasion; G3 and G7 – Smirnoff Ice® (SI), abrasion; G4 and G8 – Gatorade® (GA), abrasion). The KHN test was performed 24 h after the last cycle of erosion/abrasion. Results: The MC groups showed smaller KHN values for the SI group (p < 0.05) when compared to the Control and OJ groups; however, for the SC groups, no differences were found (p > 0.05). Conclusion: Methacrylate composite when submitted to acidic beverages erosive challenge combined with abrasive process might alter its surface microhardness. However, the beverages used in the present study were not able to interfere in silorane composite surface microhardness.

Avaliação in vitro da estabilidade de cor, da rugosidade superficial e da microdureza de materiais restauradores estéticos, após imersão em bebidas infantis ou envelhecimento artificial acelerado

“…Os monômeros que não reagiram também atuam como plastificadores da matriz resinosa, alterando as propriedades físicas do material 34 , principalmente a dureza e a rugosidade superficial 35,36 . O aumento da rugosidade, associado ao aumento de porosidades presentes na superfície das resinas compostas, promove perda de massa do material e maior sorção de água, ocasionando maior alteração de cor 37,38 .…”