J Adhes Dent 19 (2017), No. 6 12. Jan. 2018
J Adhes Dent 18 (2016), No. 2 (15.04.2016)
Page 143-149, doi:10.3290/j.jad.a35908, PubMed:27042706
Fracture Strength of Endodontically Treated Teeth Restored with Composite Overlays with and without Glass-fiber Reinforcement
Monaco, Carlo / Arena, Antonio / Scotti, Roberto / Krejci, Ivo
Purpose: To evaluate the fracture strength and the failure mode of endodontically treated teeth restored with composite resin overlays with and without glass-fiber reinforcement.
Materials and Methods: A total of 32 extracted molars were divided into four equal groups. In the NFR-NFRC (no foundation restoration, no fiber-reinforced composite) and NFR-FRC (no foundation restoration, fiber-reinforced composite) groups, only a 5-mm-thick composite resin layer sealed the pulp chamber floors, whereas in the FR-NFRC (foundation restoration, no fiber-reinforced composite) and FR-FRC (foundation restoration, fiber-reinforced composite) groups, a 3.0-mm foundation restoration was used. NFR-NFRC and FR-NFRC groups were restored with composite resin overlays, whereas NFR-FRC and FR-FRC groups were restored with fiber-reinforced composite resin overlays. All specimens were subjected to mechanical loading in a computer-controlled masticator and then the fracture resistance was evaluated. Differences in means were compared using two-way ANOVA and Tukey's test. The level of significance was set at ɑ = 0.05.
Results: All specimens successfully completed the fatigue test. The least fracture-resistant group was NFR-FRC, exceeded by FR-NFRC, NFR-NFRC, and FR-FRC, in that order, with FR-FRC being the most fracture-resistant group. Statistically significant differences were detected between the pairs NFR-NFRC/FR-FRC (p = 0.001), NFR-FRC/FR-FRC (p = 0.001), and FR-NFRC/FR-FRC (p = 0.001). Eight vertical root fractures occurred in group FR-NFRC, six in group NFR-NFRC, four in group NFR-FRC, and none occurred in group FR-FRC.
Conclusions: Within the limitations of this in vitro study, the incorporation of glass fibers and the presence of a foundation restoration were found to increase the fracture resistance and can favorably influence the fracture mode.
Keywords: molars, resin-bonded onlays, root fractures