Intraoral Scanner Evaluation of Cyclic Wear in Heated Versus Injectable Composites for Indirect Restoration

This study aimed to compare the cyclic abrasive wear behavior of an injectable composite and a preheated restorative composite when used as luting agents for indirect partial restorations, using a controlled in vitro model. A secondary objective was to evaluate the ability of an intraoral scanner (IOS) to detect wear progression in comparison with a non-contact profilometer (NCP).

Twenty extracted human posterior teeth were prepared for standardized lithium disilicate onlays and randomly assigned to two groups (n = 10): luting with an injectable composite or with a preheated restorative composite. Specimens were subjected to three-body toothbrushing abrasion for up to 22,500 cycles. Using an IOS and a NCP, wear was measured at baseline and following each brushing interval. Mixed-effects models were used to analyze surface roughness and volumetric wear (α = 0.05).

Volumetric wear increased significantly with brushing cycles for both materials (p < 0.05), with no significant differences between the injectable and preheated composites (p > 0.05). Surface roughness was significantly higher for the preheated composite compared with the injectable composite at all evaluation points (p < 0.001). No significant differences were found between IOS and NCP volumetric wear measurements, although IOS data showed greater variability at higher wear levels.

Injectable and preheated composites used as luting agents for indirect restorations showed similar resistance to abrasive wear under the conditions of this in vitro study. IOS-based wear assessment demonstrated agreement with NCP measurements, and injectable composites showed reduced surface roughness.

The present study contributes to the understanding of the wear behavior of contemporary composite materials used as luting agents and highlights the potential of IOSs as a noninvasive tool for monitoring wear over time.