Air-Abrasion With Aluminum Oxide Particles in Non-Carious Cervical Lesions: Impact on Sclerotic Superficial Layer, Surface Topography, and Restorative Adhesive Performance.

OBJECTIVE: To evaluate the effect of airborne-particle abrasion (APA) with aluminum oxide on superficial dentin sclerosis, surface topography, and bonding performance of a universal adhesive in natural non-carious cervical lesions (NCCLs), using dentin classification by the North Carolina Index (NCI) and Optical Coherence Tomography Index (OCT). METHODS: Forty-eight premolars with natural NCCLs were distributed according to dentin sclerosis classification (non-sclerotic or sclerotic) by NCI and OCT, with concordant and discordant (dentin types) classifications into four APA treatment groups (n = 8), and two untreated groups (control, n = 8, non-sclerotic and sclerotic, for adhesive testing). Pre- and post-treatment analyses included stereomicroscopy, OCT, microcomputed tomography (volume and thickness loss), and 3D optical profilometry (surface roughness). Adhesive performance of a universal adhesive was assessed by microtensile bond strength (μTBS), nanoleakage (scanning electron microscopy), and chemical mapping (micro-Raman spectroscopy). Data were analyzed with parametric and non-parametric tests (α = 0.05). RESULTS: APA did not significantly change dentin classification by NCI or OCT (p > 0.05) but removed a superficial layer (volume loss: 0.33 mm3; thickness loss: 34 μm) and significantly increased surface roughness (p < 0.001), without dentin-type differences (p = 0.38). Adhesive performance was substrate-dependent: APA improved μTBS in sclerotic dentin (per OCT) and reduced it in non-sclerotic dentin (per OCT). Nanoleakage did not differ among groups (p > 0.05). CONCLUSION: APA modified dentin surface topography without removing superficial dentin sclerosis, while the effect on bonding was substrate-dependent. CLINICAL SIGNIFICANCE: APA-induced surface modification, including volume loss and increased surface roughness, improved bonding performance in sclerotic NCCL dentin without completely removing the sclerotic layer.