Influência do pré-aquecimento do cimento resinoso em pinos de fibra de vidro anatomizados e fresados (CAD/CAM) em canais ovais: análise por micro-CT e resistência à compressão

Abstract

Oval root canals challenge conventional fiber post adaptation, compromising cementation interface homogeneity. Manual anatomical relining and computer-aided design/computer-aided manufacturing (CAD/CAM) milling have been proposed to improve post-to-canal fit, while resin cement preheating may modulate flow and polymerization. This study evaluated the effects of fiber post customization strategy (manual anatomical relining vs. CAD/CAM milling) and self-adhesive resin cement preheating (22°C vs. 69°C) on interfacial void volume and fracture resistance in oval root canals. Thirty-six human maxillary premolars with oval canals (buccolingual/mesio-distal ratio ≥ 2:1) were matched by micro-computed tomography (microCT) and allocated to four groups (n = 9) in a 2 × 2 factorial design. Specimens were cemented, scanned by micro-CT for void quantification, restored with milled crowns, subjected to thermo-mechanical aging, and loaded under oblique compression (135°; 0.5 mm/min) until failure. Two-way analysis of variance (α = 0.05) and Pearson correlation were applied. Both factors significantly affected void volume and fracture resistance, with no significant interaction. Anatomically customized posts yielded lower void percentage and higher fracture resistance than CAD/CAM-milled posts. Preheating to 69°C increased interfacial voids and reduced fracture resistance regardless of post type. A significant negative correlation was observed between void volume and fracture load. Manual anatomical customization improved cementation interface integrity and fracture resistance in oval root canals. Preheating to 69°C impaired both parameters independently.