The Effect of Newly Introduced Bleaching Agent Listerine versus the Conventional Carbamide Peroxide on the Ultrastructure and Microhardness of Tooth Enamel

Abstract

Background: Tooth bleaching is one of the most conservative and cost-effective dental treatments to enhance a person’s smile. Aim: The aim of this study was to evaluate the effect of the newly introduced prebrush bleaching agent Listerine versus carbamide peroxide on the ultrastructure and micro-hardness of the enamel.Materials and Methods: Thirty non-carious sound human premolars extracted for orthodontic reasons. Teeth samples were divided equally into three groups. Group Ӏ served as control group where specimens were immersed in artificial saliva, group ӀӀ treated with 22% carbamide peroxide for 5 sessions per day 15 minutes for 60 days and group ӀӀӀ treated with Listerine pre-brush rinse for 5 sessions per day 15 minutes for 60 days, in between the sessions teeth were kept in artificial saliva. At the end of the experiment, all teeth were hemi-sectioned longitudinal in mesio-distal direction to form 60 specimens. The lingual halves of all the groups were used for measuring enamel micro-hardness, while buccal halves were examined by scanning electron microscope (SEM) to detect any ultrastructural changes of enamel of the different groups. Results: SEM results showed morphological alterations on the enamel surface of group ӀӀ and group ӀӀӀ compared with control group Ӏ as appeared surface pitting, porosity, irregularity, roughness, craters like depression and micro-cracks. Results of enamel surface micro-hardness showedno significant differences were found among the bleaching groups (ӀӀ-ӀӀӀ) (p=0.371). However, all bleaching agents produced a significant increase in the mean value of micro-hardness of enamel compared to the untreated control group (Ӏ) as there are highly significant between group Ӏ and other groups as group ӀӀ (p=0.003) and group ӀӀӀ (p=0.026). Conclusion bleaching abuse had a negative influence on the morphology of enamel and its micro-hardness. The home dental bleaching should be done with caution.