Enhancement of Bond Strength, Degree of Conversion and Biocompatibility In Vitro Using a Hollow Glass Fiber Post With an Optical Illuminator in the Restoration of Endodontically Treated Teeth

OBJECTIVE: Evaluate an optical fiber illuminator associated with a hollow glass post on resin cement's adhesive, physicochemical, and biological properties. MATERIALS AND METHODS: To enhance light transmission throughout the root canal, a photopolymerization optical fiber device was developed. Eighty bovine teeth were distributed into five groups (n = 16): CD (Commercial post, Allcem dual-cured cement); PL (Hollow post, Allcem light-cured cement); PD (Hollow post, Allcem dual-cured cement); POL (Optical illuminator, hollow post, Allcem light-cured cement); POD (Optical illuminator, hollow post, Allcem dual-cured cement). About 2 mm slices (n = 12) from cervical, middle, and apical thirds underwent a push-out bond test, fracture analysis, conversion of monomer degree (DC%), energy dispersive spectroscopy (EDS), and MTT cytotoxicity. Micro-CT (n = 4) evaluated the cementation interface. RESULTS: Apical third exhibited higher adhesive strength compared to the middle third (p < 0.001). Fiber optic lighting with a hollow glass fiber post and dual-cured cement (POD) from apical showed the highest bond strength and DC%. EDS proved suitable chemical components. Hollow glass fiber post and dual-cured cement (PD) from apical exhibited higher cell viability compared to commercial post (p < 0.001). Micro-CT with 3D reconstruction evidenced the excellent adaptation of the post. CONCLUSION: The illuminator device efficiently improved cement's adhesive strength, degree of conversion for the dual-cured cement, especially in the apical third, and enhanced the biocompatibility of the proposed system. CLINICAL RELEVANCE: This novel optical device enhances light transmission within the root canal, improving post bonding and potentially leading to better clinical outcomes in the restoration of endodontically treated teeth.