In vivo Plaque Formation on Zirconia and Feldspathic Ceramic

Objective: The aim of this study is to compare in vivo the plaque formation on zirconia and feldspathic overlay porcelain specimens. Methods: Four volunteers were enrolled in the study. A lower removable acrylic devices for each subject were customized and samples of zirconia (N=4) (Lava Frame, 3M ESPE) and feldspathic ceramic (Lava Ceram, 3M ESPE) were adapted on the distal-lingual surface. Specimens of each material were removed at 6, 12, 24 and 36 hours; one device was randomly selected for SEM examination. A bacterial count was performed on the other 3 samples by the methodic “Real-Time PCR”; statistical analysis was performed using ANOVA (p< 0.05). Results: The electron micrographs demonstrated that the bacteria colonization was already detected after 6h in the oral cavity and at 24 -36h both materials were covered by several layers of bacterial cells. The bacterial biofilm on the zirconia specimens appear less aggregated and structured than the other one. The data obtained by microbiological analysis were: Lava Frame 6h 7,80E+06, 12h 4,65E+07, 24h 2,09E+09, 36h 5,57E+08; Lava Ceram 6h 6,83E+06, 12h 9,08E+07, 24h 2,09E+09, 36h 1,10E+09. No significant differences were observed between the two materials analyzed in this study (p=0,073). Conclusion: Same amount of microbial cells were found on zirconia and ceramic surfaces analyzed after 6,12, 24 and 36 h.