Mechanical properties of composite resin blocks for CAD/CAM

TLDR

The study compared commercial composite resin blocks with a ceramic block for use in CAD/CAM. Four composite resin blocks and two ceramic blocks were evaluated for flexural strength, flexural modulus, and Vickers hardness under dry, water‑immersion, and water‑immersion plus thermocycling conditions, with two‑way ANOVA and Tukey’s post‑hoc analysis applied. After dry storage, flexural strength ranged from 127 to 242 MPa, flexural modulus from 9.6 to 51.5 GPa, and Vickers hardness from 64 to 455, and although water immersion and thermocycling degraded these properties, they remained within the ISO 6872 acceptable limits for single‑restoration fabrication.

Abstract

This study compared commercial composite resin blocks with one ceramic block for use in computer-aided design/computer aided manufacturing (CAD/CAM). Four composite resins, one composite ceramic, and one feldspar-ceramic block were investigated. Flexural strength (FS), flexural modulus (FM), and Vickers hardness (VH) were determined under three conditions: dry storage; immersion in water at 37°C for 7 days; and immersion in water at 37°C for 7 days followed by 10,000 thermocycles. After dry storage, FS ranged from 127 to 242 MPa, FM from 9.6 to 51.5 GPa, and VH from 64 to 455. Two-way ANOVA was performed for FS, FM and VH followed by Tukey's multiple comparison (α<0.05). Results demonstrated that the materials degraded after water immersion and thermocycling, but their properties were within the acceptable range for fabrication of single restorations according to the ISO standard for ceramics (ISO 6872:2008).