The effect of amount of lost tooth structure and restorative technique on fracture resistance of endodontically treated premolars

Abstract

Aim:Endodontic treatment generally reduces the fracture resistance of teeth. The purpose of this study was to evaluate the fracture resistance and the mode of fracture of endodontically treated human premolars with different amounts of remaining tooth structure.Materials and Methods:Seventy non-carious human premolars were randomly assigned into 7 groups. Group 1 (ST) did not receive any preparation. The teeth in groups 2-7 received root canal treatment and different preparations. Group 2 (MO-NF): Mesio-occlusal preparation without filling; Group 3 (MOD-NF): Mesio-occluso-distal preparation without filling; Group 4 (MO-F): Mesio-occlusal preparation with direct composite restoration (Z250); Group 5 (MOD-F): Mesio-occluso-distal preparation with direct composite restoration (Z250); Group 6 (CC-D): Mesio-occluso-distal preparation with cusp reduction and direct composite restoration (Z250); Group 7 (CC-InD): Mesio-occluso-distal preparation with cusp reduction and indirect composite restoration (Gradia GC). The fracture resistance (N) was assessed under compressive load in a universal testing machine (Zwick) perpendicular to the occlusal surface at a cross-head speed of 1 mm/min, and the mode of fracture was assessed under stereomicroscope.Statistical analysis:Data was analyzed by Kruskal – Wallis and Mann – Whitney tests and the mode of fracture was analyzed by Chi-square test (P < 0.05).Results:Statistical analysis showed that MO and MOD cavity preparations significantly reduced the fracture resistance of sound teeth. Direct composite restorations can improve the fracture resistance, and Groups 7 and 6 presented the highest fracture resistance values.Conclusions:Teeth with adhesive restorations showed significantly higher fracture resistance values as compared with the non-restored ones.

Anin vitrocomparative evaluation of different intraorifice barriers on the fracture resistance of endodontically treated roots obturated with gutta-percha

“…[ 4 ] Furthermore, it has been shown that direct and indirect cusp coverage adhesive restorations can significantly increase the fracture resistance of endodontically treated teeth. [ 5 ] Bonding endodontic obturation materials to radicular dentin is another approach to increase fracture resistance. [ 6 7 ] Use of sealers and lateral condensation technique significantly strengthen the roots as compared to canals, which are instrumented but not obturated.…”

Effect of Alternative Palatal Root Access Technique on Fracture Resistance of Root Canal Treated Maxillary Fourth Premolar Teeth in Dogs

“…As endodontic treatment in veterinary patients is generally only indicated in teeth that have undergone previous trauma, it would also be important to consider whether changes in fracture resistance are primarily due to previous trauma sustained by the tooth or due to the biomechanical changes that are directly related to endodontic therapy. Specific areas of interest would be evaluation of the effect of cyclic loading and tooth abfraction (28-30) on fracture resistance compared to the direct effects of root canal therapy, such as dentin desiccation and specific access design (14)(15)(16)(17)(18)(19)(20).…”

“…Previous studies in human dentistry have shown that endodontically treated teeth have lower fracture resistance than vital teeth (7)(8)(9)(10)(11)(12)(13). Many factors may contribute to this decreased strength including increased brittleness of dentin secondary to desiccation, removal of hard tissue during access and instrumentation, and lack of sensory feedback from the tooth (3,(14)(15)(16)(17)(18)(19)(20). However, it has been shown that the largest contributor to fracture resistance post endodontic therapy is access method, with more conservative access design conferring increased tooth strength (14)(15)(16)(17)(18)(19)(20).…”

“…Many factors may contribute to this decreased strength including increased brittleness of dentin secondary to desiccation, removal of hard tissue during access and instrumentation, and lack of sensory feedback from the tooth (3,(14)(15)(16)(17)(18)(19)(20). However, it has been shown that the largest contributor to fracture resistance post endodontic therapy is access method, with more conservative access design conferring increased tooth strength (14)(15)(16)(17)(18)(19)(20). To the authors' knowledge, there are currently no studies in veterinary medicine evaluating the effects of endodontic therapy or specific access design on the fracture resistance of root canal treated teeth.…”

Bond to Zirconia Ceramic: Evaluation of Different Primers and a Universal Adhesive

“…For indirect restorations, different luting techniques can be employed, and the literature has shown that the use of adhesive techniques provides an increase in the fracture resistance of teeth [1,2]. Traditionally, the adhesive technique is the combination of an adhesive system with resin cement.…”