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

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

Objective: The aim of this study is to determine the effects of vital ble-aching 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 gro-ups. 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 be-fore 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.