Wear-induced changes in microhardness and surface roughness of hybrid composites: An in vitro atomic force microscopy and profilometric study

Objectives: The study evaluated the effects of toothbrushing with three different dentifrices, Colgate White (COW), Pepsodent (PEP), and Meswak (MES), on the surface roughness and microhardness of two Composite resins. Material and Methods: Bar-shaped specimens of two CRs - Filtek P60 and Filtek Z250 XT - were prepared ( n = 10). Samples were subjected to 10,000 brushing cycles using a simulator (2N, 60 Hz). Post-brushing, surface roughness was measured using a non-contact profilometer and atomic force microscopy, while microhardness was assessed through the Vickers method. Data were statistically analyzed using analysis of variance and regression analysis (α = 0.05). Results: All groups exhibited increased surface roughness and decreased microhardness post-brushing. The most significant alterations were observed in specimens brushed with COW, while MES produced the least changes. No significant differences were observed between the two resin types. Conclusion: Toothbrushing with abrasive dentifrices on the surface and the mechanical properties of the composites were tested. The extent of degradation was dependent on the dentifrice used. The abrasiveness of dentifrices should be considered when recommending oral hygiene products to patients with composite restorations, as it may influence the longevity and appearance of the restorative material.