Marginal integrity and clinical evaluation of polyetheretherketone (PEEK) versus lithium disilicate (E-Max) endocrowns

Aim:  Evaluate the marginal integrity and Clinical performance of PEEK endocrowns compared to lithium disilicate (E-Max) ceramic endocrowns. Methodology: Twenty six endocrowns were fabricated for posterior endodontically treated teeth. Patients were divided into two groups according to the material used for fabrication of the restorations; Group 1(control group) received E-Max endocrowns while Group 2 (intervention group) received Bio HPP PEEK endocrowns. The marginal integrity and internal fit were assessed using the silicon replica approach, in which each replica was sectioned into four segments, each with five reference points that were evaluated using a digital microscope at 35X magnification. After final cementation, the clinical performance of the restorations was evaluated according to the USPHS criteria in terms of marginal adaptation, fracture, and retention. These measurements were repeated after three, six, nine and twelve months respectively. Results: The marginal and internal gaps of both groups were within the clinical acceptable range, but E-Max group recorded statistically significant higher internal gap mean value than PEEK group. Regarding the clinical performance all restorations showed 100% alpha and there was no significant difference between both groups for all tested outcomes (Marginal adaptation, fracture, and retention) over one year.