Laser-assisted cerium oxide mineralization for dentinal tubule occlusion.

OBJECTIVES

This study aimed to develop a synergistic strategy integrating in-situ deposition of cerium hydroxide with laser irradiation to achieve efficient and acid-resistant occlusion of dentinal tubules (DTs) for dentin hypersensitivity (DH) management, while conferring antibacterial activity to the dentin surface.

METHODS

An "alternate soaking" approach, involving alternating immersions in 5 wt% cerium nitrate and 0.5 wt% sodium hydroxide solutions, was utilized to deposit cerium hydroxide onto type I collagen fibrils and demineralized dentin. Subsequent Nd:YAG laser irradiation of the remineralized dentin surface converted cerium hydroxide into cerium oxide, effectively sealing the DTs. The morphology and occlusion stability were characterized using SEM, TEM, and EDX, while FTIR, XRD and SAED analyses examined the laser-induced conversion of cerium hydroxide to cerium oxide. The antibacterial activity against Streptococcus mutans was assessed using colony forming unit (CFU) assay and SEM, while the biocompatibility was evaluated via CCK-8 assay, CLSM and oral mucosa irritation test.

RESULTS

The alternating soaking approach rapidly mineralized type I collagen fibrils with cerium hydroxide. Under irradiation of Nd:YAG laser, cerium hydroxide underwent conversion to cerium oxide, achieving deep occlusion of dentinal tubules with acid-resistant properties. The modified dentin surface demonstrated significant antibacterial activity against S. mutans and excellent biocompatibility.

SIGNIFICANCE: Alternate soaking with cerium nitrate and sodium hydroxide, followed by Nd:YAG laser irradiation, promotes rapid mineralization of demineralized dentin, effectively occludes DTs, and imparts antibacterial properties to the dentin surface. This underscores its potential as a novel approach for managing DH.