[Evaluation methods of nightguard teeth bleaching with opalescence (ultradent) based on clinical and experimental...

In March 1989 Haywood and Heymann presented a new method for bleaching teeth called by them "nightguard vital bleaching". This procedure requires that the patient wears for 6 to 8 hours an individually designed guard filled with a viscous solution of carbamide peroxide. The aim of the present study was to determine the efficiency of the guard bleaching method and to address frequently asked questions concerning local complications and the influence of the preparation on the enamel surface. The scanning electron microscope was used in the experimental part to reveal changes in microhardness and on the surface of the bleached human enamel. The purpose of the clinical part was to determine the efficiency of bleaching, to estimate the frequency of pain and other symptoms and to check the influence of bleaching guard on accumulation of dental plaque and gingival status as reflected by the Plaque Index (Pl.I.) and the Gingival Index (G.I.). It was found that bleaching with 10, 20 or 35% carbamide peroxide reduced the microhardness and modified the morphology of enamel surface proportionally to the concentration of the bleaching agent. It was ascertained that 10% carbamide peroxide effectively bleached teeth and considerably improved the hygiene of the oral cavity and gingival status (Pl.I, G.I.). During bleaching, over half of the patients suffered from local complications--thermal hypersensitivity of teeth and irritation of gums. Some deterioration of the bleaching effect was observed after 12 months in females only. Almost 100% of the patients were satisfied with the results of bleaching and would recommend this procedure to family members.