Lithium disilicate and PEEK implant-retained single crowns - a randomized, prospective clinical study

Introduction/Objective. Comparing two materials under the same conditions is the best way to define differences between them. Ceramic-reinforced polyether-etherketone (PEEK) is a polymer that has many possible uses in dentistry as already well-known lithium disilicate ceramics. The aim of this study was to compare peri-implant soft tissue healing and evaluate patient satisfaction with esthetics in different observation periods, as well as the success and survival rate of both types of crowns. Methods. The study was conducted as a clinical, prospective, randomized split-mouth study on 17 patients with bilaterally missing upper teeth of the same type, replaced with dental implants. Study outcomes have been analyzed with subjective (visual analogue scale ? VAS scale) and objective parameters (modified bleeding index ? MBI, modified plaque index ? MPI and peri-implant probing depth ? PPD) baseline, six and twelve months after fixing crowns onto the implants. Results. Comparison of the results between PEEK and lithium disilicate crowns showed no statistical differences in terms of MPI, MBI, and PPD in the observed periods. Analyzing MPI during observation periods in the PEEK group of crowns, statistical significance was registered between baseline values and after six months. Also, statistical significance was noticed in terms of PPD during the observation time both in the study and control group of crowns. Results for VAS for the esthetics showed no statistically significant difference between the groups, while VAS for restoration satisfaction showed a statistically significant difference. Conclusion. This study showed that scores of the applied subjective and objective parameters can be a reliable tool to rate the clinical outcome of implant-retained single crowns over time.