Comparative evaluation of compressive strength of CAD-CAM polyetheretherketone and indirect composite Class II inlays: an in vitro study

Polyetheretherketone (PEEK) is a high-performance thermoplastic polymer that is currently being utilized in the dental field due to its desirable mechanical characteristics, biocompatibility, and ease of integration into digital CAD-CAM processes. Despite the esthetic and esthetic benefits of composite resins in Class II inlays, mechanical performance in high-stress posterior restorations continues to be a clinical issue with the material. Although other research has been conducted to utilize PEEK in different dental treatment procedures, there are no direct comparative studies dealing specifically with the compressive strength of Class II dental restorations using CAD-CAM developed PEEK inlays as compared to indirect composite inlays. This study aimed to compare the compressive strength of PEEK and composite resin when used as Class II inlays and evaluate PEEK's suitability as an alternative restorative material. Thirty-four human premolars extracted for orthodontic reasons and randomly allocated to two groups (n = 17). Group A was provided with CAD-CAM-produced PEEK inlays, and Group B was restored with inlays made of an indirect composite. Fracture load testing of all specimens was done through a universal testing machine. An independent t -test was used to statistically analyze the compressive strength values. The PEEK group showed a mean compressive strength value of 381.88 N compared to 266.67 N in the composite group, and the p-value was below 0.001, which was a statistically significant difference. PEEK inlays proved to have better compressive strength than composite resin inlays, which implies that PEEK is a prospective Class II restorative material in stress-bearing posterior areas. Its clinical performance over the long term and in more applications should be the subject of future research.