Clinical Cytotoxicity of Gold and CAD-CAM Crowns

Objective: This study investigated the cytotoxicity of natural saliva containing elemental ions released from gold and CAD-CAM fabricated ceramic crowns. Methods: Twenty patients receiving full coverage crowns were divided into three groups: a) gold crowns (ORO 60), b) CAD-CAM fabricated All ceramic crowns (Empress CAD) c) combined (gold and CAD-CAM). Saliva collection and clinical evaluation of marginal integrity and gingival health were performed using California Dental Association criteria before crowns preparation, three months and six months after crowns placement. Saliva samples were tested for cytotoxicity by culturing mouse L-929 fibroblasts for a 7-day period of incubation. Then, the percentage of viable cells for each element was measured using trypan blue exclusion assay. A well without any tested element and another with artificial saliva were used as negative controls. Normality tests were conducted then the data were statistically analyzed by ANOVA/Tukey test. Results: The lowest percentage of viable cells (31.5±11.7) was evident in the Gold crown 3 month recall (p<.001) indicating that it releases the most toxic elements which improved at the 6 month recall (40.8±13.7). CAD-CAM crowns showed less toxic effect (49.1±11.1) at 3 months and (65.9±15.2) at 6 months. Combined samples had (45.0±2.0) at 3 months and (65.3±23.8) at 6 months post insertion. No obvious adverse effects on marginal integrity nor gingival health were noticed. Conclusions: Gold alloy full crowns showed evidence of prominent cytotoxic effect on fibroblasts cell cultures.