Streptococcus-mutans and Porphyromonas-gingivalis adhesion to glazed/polished surfaces of CAD/CAM restorations

Dental restorations fabricated using CAD/CAM require modification/adjustment before cementation. Streptococcus mutans (S.mutans) and Porphyromonas gingivalis (P.gingivalis) are prevalent bacterial species that may adhere to these materials and can cause caries, gingivitis/periodontitis. The purpose of this in vitro study was to evaluate the bacterial adherence of S.mutans and P.gingivalis to five different kinds of modern CAD/CAM restorative materials with different compositions following chairside finishing/polishing and glazing.

Specimens (N = 75) from five test materials (n = 15 each) "Tetric-CAD®; IPS-e.max-CAD®; IPS-e.max-ZirCAD®; CELTRA-Duo® and Vita-Enamic®" were prepared in disc shape (10 × 3 mm) using CAD/CAM. The specimens underwent glazing and finishing/polishing using established procedures. The surface roughness was measured in micrometers (μm) using a profilometer. Bacterial adherence to test materials' glazed and finished/polished surfaces was tested using bacterial culture growth over the test materials. Data obtained was tabulated and statistical analysis performed using Kruskal Wallis test, post-hoc Conover test, Mann-Whitney U test and Tukey post hoc test.

With the exception of IPS-e.max-ZirCAD®, which showed the contrary, the adherence of S.mutans & P.gingivalis was less on glazed surfaces compared to finished/polished surfaces for four test materials: "Tetric-CAD®, IPS-e.max-CAD®, CELTRA-Duo®, and Vita-Enamic®". On the glazed surfaces, the adhesiveness of S.mutans and P.gingivalis was not significant (p = 0.099; p = 0.660); however, on the finished/polished surfaces, it was significant (p = 0.002; p = 0.004). With the exception of 'IPS-e.max-ZirCAD®', which showed the reverse behavior, the adhesion of S.mutans & P.gingivalis to finished/polished surfaces was greater for each of the four ceramics under investigation "Tetric-CAD®, IPS-e.max-CAD®, CELTRA-Duo®, and Vita-Enamic®".

Glazed surfaces for majority of test materials demonstrated decreased adhesion from S.mutans & P.gingivalis, hence prior to final placement of restoration, it is advised to adhere to the minimal glazing criteria. Regardless of the chemical composition of the materials, the surface texture of the tested materials significantly influenced bacterial adhesion.