Among esthetic procedures, teeth whitening is a common and often used treatment for patients who seek good teeth appearance. We developed an experimental green tea extract and an experimental green tea gel for enamel restoring treatment after bleaching. We also tested the antibacterial and antifungal effect of the experimental extract against specific endodontic and cariogenic microorganisms. The green tea extract antibacterial action was determined by the disk-diffusion method using Peptostreptococcus anaerobius (ATCC27337), Corynebacterium xerosis (ATCC 373), Streptococcus mutans (ATCC 25175) and Candida albicans (ATCC 10231) strains. Enamel microstructure was investigated by SEM analysis, and surface details were revealed by AFM. The inhibition zones around the wells showed evident antimicrobial activity of the experimental extract. In the presence of Candida albicans (ATCC 10231), the extract showed no antifungal activity. The enamel’s surface roughness and hydroxyapatite prism aspects were the parameters followed throughout the study. The experimental green tea extract is efficient against some microorganisms commonly found in the oral cavity. However, the studied extract had no antifungal effect. The results show that after bleaching with the experimental gel, we obtained the best surface parameters, similar to healthy enamel.

Esthetics of the enamel surface is an important factor for a good oral health care. The mastication process could damage the enamel surface by hydroxyapatite layer alteration via local demineralization and micro scratches. We developed an experimental green tea extract gel for enamel restoring treatment. Microstructure features were investigated by SEM microscopy and the surface details were revealed by AFM. The surface roughness and hydroxyapatite grains size and shape were the parameters followed into the investigation. The results show that the best restoring is obtained by the experimental gel leading to surface parameters similar to the healthy enamel better than the values obtained with opalescence carbamide gel.

The effect of the color change of stained and then bleached composite resins blocks have been evaluated. 28 blocks, made from Admira fusion composite resin and divided in 3 groups, were included in the present study. They were stained in coffee for 3 days and then bleached with Opalescence gel (GO) and experimental bleaching gel based on green tea extract (GE). All color indices were measured in all situations (initially, after staining and after bleaching) with Vita Easy Shade spectrophotometer. It was used the CIE*L*a*b system for the color change parameters. The group bleached with Opalescence presented the most significant color changes. The bleaching effect of the experimental gel is lower that Opalescence bleaching gel.