Fatigue behavior of endodontically treated premolars restored with different fiber-reinforced designs

• Published in: Dental materials 2021-03, Vol.37 (3), p.391-402
• Main Authors: Fráter, Márk, Sáry, Tekla, Jókai, Blanka, Braunitzer, Gábor, Säilynoja, Eija, Vallittu, Pekka K., Lassila, Lippo, Garoushi, Sufyan
• Format: Article
• Language: English
• Subjects: Bicuspid; Bioblock technique; Composite Resins; Dental caries; Dental restorative materials; Dental Stress Analysis; Dentistry; Endodontically treated teeth; Endodontics; Fatigue; Fatigue strength; Fatigue survival; Fiber composites; Humans; Materials Testing; Post and Core Technique; Premolar teeth; Premolars; Root Canal Therapy; Root canals; Short fiber-reinforced composite; Short fibers; Survival; Teeth; Tooth Fractures; Tooth, Nonvital
• ISSN: 0109-5641; 1879-0097
• DOI: 10.1016/j.dental.2020.11.026

•Unidirectional FRC post is needed in restoration of ETT premolars.•Unidirectional FRC post can be luted with flowable SFRC.•Application of flowable SFRC as luting-core material with FRC post offer fatigue-survival similar to intact premolars. The aim was to investigate the fatigue survival and marginal-gap inside the root-canal of endodontically treated (ET) premolars reinforced by various fiber-reinforced post-core composites (FRCs). Moreover, composite-curing at different depths in the canal was evaluated. 170 intact upper-premolars were collected and randomly divided into ten groups (n = 15). One group served as control (intact-teeth). After endodontic procedure standard MO cavities were prepared and restored with different post-core fiber-reinforced materials and designs. Three-group (A1-A3) were restored with either packable and flowable short fiber-reinforced composite (SFRC) core or conventional composite-core. Two-group (B1-B2) were restored with SFRCs as short post (3 mm) and core. Four-group (C1-C4) were restored with SFRCs as post (6 mm) and core with or without unidirectional FRC posts (individually-made or conventional). After completing the restorations, teeth from Group C1-C4 (n = 5/group) were sectioned and stained. Specimens were viewed under a stereo-microscope and the percentage of microgaps within the root-canal was calculated. Fatigue-survival was measured using a cyclic-loading machine in the rest of the specimens. Application of flowable SFRC as luting-core material with individually-made FRC post (Group C3) did not differ from intact-teeth regarding fatigue-survival (p > 0.05). The rest of the groups produced significantly lower survival (p < 0.05) compared to intact-teeth. Post/core restorations made from packable SFRC (Group C1) had a lower microgap (19.1%) at the examined interphase in the root-canal than other groups. The restoration of ET premolars with the use of individually-made FRC post and SFRC as luting-core material showed promising achievement regarding fatigue-resistance and survival.