In Vitro Investigation of Surface Roughness and Bacterial Adhesion on Different Dental Porcelains Applying Different Vital Whitening Agents

Abstract

Statement of the problem: Studies on the effects of vital bleaching agents on the surface roughness and bacterial adhesion of different dental porcelain materials are insufficient.

Objective: The aim of this study is to determine the effects of vital bleaching procedures on the surface roughness of different dental porcelains and to investigate whether they facilitate bacterial adhesion.

Materials & Methods: A total of 60 porcelain discs, 12 mm in diameter and 2.2 mm in thickness, were produced from two feldspathic porcelains and one leucite-enriched all-ceramic. The sample groups (n=20) manufactured from Ceramco 3, VMK 95, and Finesse TM were named as C, V, and F respectively.  Two bleaching agents were applied to 20 samples belonging to C, V and F groups. The group bleached with 16% carbamide peroxide gel was called the N group. The group bleached with 10% carbamide peroxide gel was called the R group. A total of 6 experimental groups, CN, VN, FN, CR, VR and FR, were formed. Streptococcus mutans strain was used to detect bacterial adhesion before and after bleaching on porcelain surfaces with and without a pellicle layer, and adhesion was determined by colony counting method. The obtained data were analyzed with Kruskal-Wallis test and Spearman’s correlation coefficient.

Results: The mean difference in bacterial adhesion colony counts of VN and VR groups was found statistically significant (P < 0.05). Application of Nite-White bleaching agent on Finesse porcelain increased the adhesion more (P < 0.05). The difference in the number of Streptococcus mutans bacteria adhesion colonies among the other groups was not statistically significant (P > 0.05).

Conclusion: The bleaching process could affect the surface roughness of dental porcelain and facilitate bacterial adhesion to the porcelain surface.