Evaluation of the Marginal Fit and Fracture Resistance of Polyetheretherketone (PEEK) and Zirconia Copings: An In-vitro Study.

Introduction: In dentistry, there has been an increasing demand for aesthetics and biocompatible restorations with low plaque affinity. The success of any restoration is based on three main factors: marginal fit, fracture resistance, and aesthetics. Polyetheretherketone (PEEK) is a polymeric material that has emerged as a novel thermoplastic material with wide applications. Aim: To evaluate the marginal fit and fracture resistance of PEEK and zirconia copings fabricated using Computer-aided Design (CAD)/Computer-aided Manufacturing (CAM) technology. Materials and Methods: The present in-vitro study was conducted in the Department of Prosthodontics, MM College of Dental Sciences and Research, Mullana, Ambala, Haryana, India, from November 2022 to March 2024. The present study compared the marginal fit and fracture resistance of PEEK and zirconia copings fabricated using CAD/CAM technology. All-ceramic tooth preparations were performed on extracted maxillary first premolars, and the prepared teeth were scanned. Using three dimensional (3D) printing technology, 20 resin dies were obtained. These dies were divided into two groups: 10 for PEEK and 10 for zirconia. Ten copings for zirconia and PEEK were fabricated using CAD/CAM technology, and two reference points were marked on the copings. The copings were luted with resin cement on the dies, and marginal fit and fracture resistance were recorded. The observations were statistically analysed using a two-way Analysis of Variance (ANOVA) test and a two-sample t-test. Results: The lowest mean marginal discrepancy values (18.469±6.55 μm for the palatal aspect and 17.116±6.34 μm for the buccal aspect) were observed for the zirconia copings. These values were significantly better compared to the PEEK copings (23.941±7.73 μm on the palatal aspect and 22.338±7.89 μm on the buccal aspect). In terms of fracture resistance, PEEK copings demonstrated a higher load-bearing capacity (523.11±117.27 N) and significantly better results compared to zirconia copings (395.4±150.93 N). Conclusion: The results revealed that, when comparing both PEEK and zirconia copings, zirconia copings demonstrated a better marginal fit compared to PEEK copings. However, for fracture resistance analysis, PEEK copings exhibited better load-bearing capacity than zirconia copings. [ABSTRACT FROM AUTHOR]