Abstract
The purpose of this in-vitro study was to evaluate the fracture resistance and failure mode of non-invasively reinforced endodontically treated mandibular molars. Sixty freshly extracted defect-free mandibular molars were divided into four experimental groups with extensive MOD cavities on endodontically treated teeth with different restoration types and one control group with intact teeth (n = 12). The groups were as follows: “Normal”: direct resin composite; “Ring”: glass fiber-reinforced strip (Dentapreg) wrapped around buccal and lingual walls followed by direct resin composite; “Inlay”: indirect CAD/CAM resin composite inlay; “Onlay”: indirect CAD/CAM resin composite onlay; “Intact”: Intact teeth (Control). Tetric EvoCeram and Adhese Universal (Ivoclar Vivadent) were used for direct restorations and Tetric CAD (Ivoclar Vivadent) adhesively luted with Adhese Universal and Variolink Esthetic LC (Ivoclar Vivadent) were used for indirect restorations. All teeth were submitted to thermo-mechanical cyclic loading. All samples were then submitted to a compressive load until fracture. Fracture load was noted and teeth were analyzed to classify the failure mode as either catastrophic (C) or non-catastrophic (NC). No statistically significant difference was found between fracture strength of the five groups when all specimens were considered (p = 0.1461). Intact group showed the lowest percentage of catastrophic failures (41.67%). Ring group presents less catastrophic failures (75%) than Normal group (83.34%), and failures of indirect restorations—Inlay and Onlay—were almost all catastrophic (91.67% and 100%, respectively).
Highlights
Fragility of endodontically treated teeth (ETT) is mostly due to accumulated tissue loss resulting from carious lesions, endodontic access cavities and canal preparation [1]
Fiber-reinforced teeth were compared to normal resin composite restored teeth and to inlay and onlay indirect restorations
Difference among the average fracture load of the five groups has been tested using a one-way analysis of variance (ANOVA) followed by a Sheffé post-hoc test for pairwise comparisons
Summary
Fragility of endodontically treated teeth (ETT) is mostly due to accumulated tissue loss resulting from carious lesions, endodontic access cavities and canal preparation [1]. Researchers tried to resolve this problem by either using adhesive restorations that can limit the deflection, or through redirecting lateral forces into vertical ones by covering the cusps with an indirect restoration Despite the latter technique being the most recommended [4,5,6,7,8], restoration of posterior ETT remains an issue in everyday treatment decision making. This proof of principle study showed that mechanical consolidation of buccal and lingual walls reduced cusp deflection and stress values at the cervical level of the tooth If proven beneficial, this technique could allow the restoration of large MOD cavities on ETT with a direct technique, without cusp reduction and further tissue sacrifice. The tested null hypotheses were that fiber-reinforcing rings have no influence on (1) the fracture strength and (2) and the fracture mode of ETT
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
