Healing process of gingival epithelium following irradiation by carbon dioxide laser: a study in monkeys

Abstract

Objective: The purpose of this study was to investigate the healing process of gingival epithelium of monkeys after de-epithelialization by carbon dioxide laser irradiation. Methods: Buccal attached gingiva (width >4 mm) of two adult rhesus monkeys was irradiated by carbon dioxide laser in scanning mode at constant speed, forming 16 de-epithelialized regions of 4 mm in diameter. The parameter of laser irradiation was 8 w 0.03 s on/0.05 s off (509.6 J/cm 2). After irradiation, the healing process of gingival epithelium and connective tissue was investigated at 0, 1, 2, 3, 4, 7, 10, 14 days and biopsy was performed. Histological examination was made with H–E stain. Results: Based on gross and histological examination: (1) the layer of gingival epithelium was removed completely by carbon dioxide laser. (2) Gingival epithelium regenerated at an average speed of 0.67 mm/day following carbon dioxide laser irradiation. It took gingival epithelium 4 days to cover the de-epithelialized area and 10 days to heal entirely. The adjacent connective tissue healed at 14 days. No obvious hemorrhage, inflammation or scar formation was found. Conclusions: Gingival tissue tends to heal well after de-epithelialization by carbon dioxide laser irradiation. There is no obvious delay in the regeneration of gingival epithelium following carbon dioxide laser de-epithelialization.