Compressive Strength Evaluation of Bioceramic Materials and Their Effect on Fracture Resistance of Repaired Coronal Perforations in Premolars: A Finite Element Analysis and In Vitro Study

Objectives: This study aimed to (i) compare the 28-day compressive strength of four bioceramic cements—Biodentine XP (BXP), NeoMTA2 (NMTA), ProRoot Mineral Trioxide Aggregate (MTA) (PMTA), and EndoSequence Bioceramic (BC) Root Repair Material (RRM) Fast Set Putty (EBC); (ii) evaluate fracture resistance following coronal perforation repair in a mandibular premolar three-dimensional model at bone levels above and below the perforation site using finite element analysis (FEA); and (iii) corroborate findings using extracted premolars following the same protocol. Methods: Cylindrical specimens (n ≥ 12/material) were fabricated and tested after 28 days using an Instron machine. A mandibular premolar underwent endodontic treatment, buccal perforation 3 mm below the cemento-enamel junction, restoration, and cone-beam computed tomography imaging. FEA models simulated a sound tooth (ST), an endodontically treated tooth (ETT), and perforated teeth repaired with each material. Von Mises stress distribution and tooth displacement were analyzed. Extracted premolars (n = 12) underwent perforation repair and fracture testing for FEA confirmation. Statistical analyses included one-way ANOVA and Kruskal–Wallis tests (α = 0.05). Results: BXP and PMTA demonstrated significantly greater compressive strength and elastic modulus than NMTA and EBC (p < 0.001). FEA showed no differences among repair materials, although perforation models differed from ST and ETT controls. Bone levels below the perforation increased maximum stress and displacement. Restored specimens failed at lower loads than intact teeth, and no material significantly improved fracture resistance. Conclusions: Perforation repair did not restore natural tooth biomechanics. Based on compressive strength and FEA findings, BXP and PMTA demonstrated the greatest theoretical reinforcement potential for premolars with coronal perforations.