Effect of horizontal position of fiber post placement on fracture resistance and location in endodontically treated premolars with a MOD preparation

Aim: To evaluate the effect of the position of fiber post placement on fracture resistance and location in endodontically treated teeth. Methodology: Forty healthy double-rooted human first premolars were divided into five groups. S: healthy teeth without intervention; C: endodontic treatment with MOD cavity preparation; CR: restoration with composite resin; CMP: fiber post placed horizontally in the center of the middle third of the crown; CAP: fiber post placed horizontally 2 mm below the center of the middle third of the crown. After thermocycling and fracture strength tests using a universal test machine, pulp floor involvement was evaluated. The Tukey test was used for statistical analysis. Results: Means and standard deviations of fracture strength (N) were as follow. S: 2451A±552.9; C: 32.63B±4.89; CR: 398.7C73.8; CRMFP: 1253D ±82.15; and CRAFP: 1156D±88.23 (different letters indicate statistical differences, P> 0.05). Posts placed 2 mm below the center of the middle third of the crown were associated with catastrophic fractures of the pulp chamber floor. Conclusions: The position of a fiber post seems to affect fracture location. The use of fiber posts, regardless of position, increases fracture resistance of endodontically treated teeth.