Fracture Resistance Evaluation and Failure Modes Rating Agreement for Two Endocrown Designs: An In Vitro Study

This in vitro study aimed to evaluate the fracture resistance and mode of failure endocrowns with proximal extension design compared conventional design, assess agreement evaluators on mode. Twenty mandibular third molars free caries approximately similar root lengths crown dimensions were sectioned parallel occlusal plane 2 mm above cementoenamel junction (CEJ). Then, pulp chambers canals accessed, cleaned, smoothed for path insertion. To achieve a symmetrical chamber an average depth 3 mm, filled flowable resin composite. teeth randomly divided into two groups (n = 10). The control group has all walls at same level. test had box wall apical buccal lingual Endocrowns 20) different designs (conventional extensions) fabricated using lithium disilicate (IPS e.max CAD, Ivoclar Vivadent, Schaan, Liechtenstein). After cementation, specimens loaded round-end vertical loading tip rate 0.5 per minute until (INSTRON, Norwood, MA, USA). fractured collected evaluation assessment. Statistical analyses performed Mann-Whitney U-test (α 0.05) analysis Cohen’s Kappa inter-rater reliability. showed non-significant difference between (p 0.142). However, endocrown more catastrophic failures than design. Adding boxes did not negatively impact restoration. Visualization line tracing their end by direct vision or other diagnostic tools is essential part endocrowns. Endodontically treated molar might be restored extension. Clinicians should take extra care when visualizing lines as it very misleading.