Effect of restoration technique on resistance to fracture of endodontically treated anterior teeth with flared root canals

Abstract

This study was designed to compare the impact of post and core systems on resistance to fracture of endodontically treated anterior teeth with flared root canals and to assess their fracture pattern. Sixty central incisors were cut horizontally 2 mm coronal to the cementoenamel junction (CEJ). After root canal therapy, teeth were assigned into 6 groups ( n =10 each) based on a post system and used as follows: Group C, non-flared root received size #1 glass fiber posts (Control); Group AP, flared root restored with anatomical post; Group RC, flared root restored with size #1 fiber post and cemented with thick layer of resin cement; Group CR, flared root restored with size #1 and reinforced with composite resin; Group CM, cast post-core; Group CP, CAD/CAM polymer-infiltrated ceramic post and core. Following post cementation, core build-up and crown insertion, the specimens were thermo-cycled up to 10,000 cycles (5C/55C; 30 seconds dwell time, 6 seconds transition time) and then statically loaded at 1 mm/minute crosshead speed using a universal testing machine. One-way ANOVA and Tukey HSD post hoc test (α=0.05) were used for data analysis. Group C recorded significantly higher resistance to fracture values [(826.9±39.1) N] followed by group CP [(793.8±55.6) N] while group RC yielded the lowest fracture resistance values [(586.7±51.4) N]. The resistance to fracture of wide root canals can be enhanced by using one-piece CAM/CAM post and core as an alternative to the use of either glass fiber post, relined with composite resin increasing the thickness of luting cement or the use of cast post and core system. However, this was an in vitro investigation and further in vivo studies are necessary.

Effect of intracanal diode laser irradiation on fracture resistance of roots restored with CAD/CAM posts

“…It is imperative to highlight the increased fracture resistance that the CAD/CAM system provides to the root 6,38 , which supports the choice of this system in the present study. Moreover, the specimen survival rate in groups 2 and 3 was higher than that in group 1, i.e., there was less root fracture -except for the fracture of copings in specimens number 1 and 4 in groups 2 and 3, respectively -which is consistent with the results reported in other studies 5,6,39 .…”

“…Recent studies have shown that CAD/CAM-fabricated intraradicular posts increase root fracture resistance, providing an alternative to the use of prefabricated and cast metal posts 5 . An in vitro study 6 compared the fracture resistance of flared canals restored with CAD/CAM post-and -core with prefabricated glass fiber and cast gold alloy posts.…”

Bond strength and internal adaptation of customized glass fiber posts using different bulk-fill flow resins

“…Thus, regarding the teeth with large root canals ( 15 ), and bulk-fill composites properties ( 16 , 17 ), this study has proposed an experimental technique of customization and cementation of glass fiber posts using bulk-fill flowable composites. Therefore, the aim of the present study was to evaluate the bond-strength and internal adaptation of customized glass fiber posts using different bulk-fill flowable composites, customized glass fiber posts using conventional composite resin, and fiber posts with no customization.…”

Effect of intraradicular reinforcement strategies on the fracture strength of endodontically treated anterior teeth with overflared canals

“…Bubbles, cracks, and gaps are more likely to form in thick cement, creating a concentrated stress area and reducing bond strength. Several techniques have been proposed to solve this problem, including restoration of the root canal with composite resin to decrease canal width, direct and indirect anatomical shaping of fiber posts with a composite resin, and the use of accessory posts ( 13 , 14 , 18 , 21 ). Another technique proposed in the present study uses dual-cured core build-up composite resin instead of self-adhesive resin cement for simultaneous reinforcement and cementation of fiber posts to overflared canals.…”

“…demonstrated that direct and indirect anatomic posts could be an alternative to cast metal post-and-cores during the treatment of overflared root canals ( 15 ). Some studies have recently proposed another method for relining and reinforcing weakened root canal walls with composite resin before fiber post cementation ( 10 , 17 , 18 ). Gomes et al .…”