PMID- 38109392 OWN - Quintessenz Verlags-GmbH CI - Copyright Quintessenz Verlags-GmbH OCI - Copyright Quintessenz Verlags-GmbH TA - Int J Prosthodont JT - The International Journal of Prosthodontics IS - 1942-4426 (Electronic) IS - 0893-2174 (Print) IP - 6 VI - 36 PST - ppublish DP - 2023 PG - 712-721 LA - en TI - Influence of Post Length, Post Material, and Substance Loss on the Fracture Resistance of Endodontically Treated Teeth: A Laboratory Study LID - 10.11607/ijp.7468 [doi] FAU - Samran, Abdulaziz AU - Samran A FAU - Mourshed, Bilal AU - Mourshed B FAU - Ahmed, Mohammed A. AU - Ahmed M FAU - Al-Akhali, Majed AU - Al-Akhali M FAU - Kern, Matthias AU - Kern M CN - AB - Purpose: To evaluate the effects of post length, post material, and substance loss on the fracture resistance of endodontically treated mandibular premolars. Materials and Methods: A total of 96 extracted human mandibular first premolars were endodontically treated and divided into 12 test groups (n = 8 each) based on the number of residual walls (one/two), post material (glass-fiber/titanium), and post length (5 mm, 7.5 mm, and 10 mm). After luting the posts, specimens received a composite resin core and a crown preparation with a 1.5-mm ferrule. Cast cobalt-chromium crowns were cemented using glass-ionomer cement. After 1,200,000 chewing cycles with a load of 49 N and simultaneous thermocycling (5°C to 55°C), specimens were quasi-statically loaded at 30 degrees to the longitudinal axis of the tooth until fracture. Fracture loads were analyzed using three-way, two-way, and one-way ANOVA (α = .05). Fracture modes were examined under a stereomicroscope (×25 magnification) and recorded. Results: The mean ± SD fracture loads ranged from 642 ± 190 N (one wall, glass fiber, 5 mm) to 1,170 ± 130 N (two walls, titanium, 7.5 mm). The mean fracture load of titanium posts was significantly higher than that of glass-fiber posts (P < .001), and the 7.5-mm post length exhibited significantly higher fracture loads than groups with 5-mm and 10-mm post length (P = .008). Conclusions: Teeth restored with titanium posts revealed considerably higher fracture resistance than teeth restored with glass-fiber posts, especially if 7.5-mm–length posts were used. AID - 1217085