A clinical evaluation of chairside lithium disilicate CAD/CAM crowns A two-year report

Background. Developments in ceramic material science have led to improvements in the physical properties of modem ceramics, leading to a substantial increase in the clinical use of all-ceramic restorations. The authors evaluated the clinical performance of lithium disilicate (IPS e.max CAD, Ivoclar Vivadent, Amherst, N.Y.) all-ceramic crowns. Methods. The authors fabricated 62 lithium disilicate crowns with a chairside computer-aided design/computer-aided manufacturing (CAD/CAM) system (CEREC 3, Sirona Dental Systems, Charlotte, N.C.) and cemented them with two types of adhesive resin cements. Two examiners used modified U.S. Public Health Service criteria to evaluate the crowns at baseline, six months, one year and two years. Results. There were no clinically identified cases of crown fracture or surface chipping. There was no reported sensitivity at one or two years with either cement. For margin discoloration, the percentage Alfa score was 86.9 percent for crowns cemented with a self-etching, dual-curing cement. All other percentage Alfa scores were greater than 92.0 percent, indicating no appreciable change in the crowns during the two-year study. Conclusions. The results show that lithium disilicate crowns performed well after two years of clinical service. Clinical Implications. Early results indicate that monolithic lithium disilicate CAD/CAM crowns may be an effective option for all-ceramic crowns.