In Vitro Fracture Resistance of Endodontically-treated Maxillary Premolars

Abstract

Horizontal pins alone, or with flowable composite, have no effect on the fracture resistance of endodontically-treated maxillary premolars restored with resin composite. SUMMARYMany endodontically-treated teeth require quick, simple, low-cost restorations. This study evaluated the effect of horizontal pins and flowable composites on the fracture resistance of endodontically-treated maxillary premolars directly restored with resin composite.In this in vitro study, 64 intact human maxillary premolars, extracted for orthodontic reasons, were randomly divided into four groups of 16.Standard access cavities were prepared in such a way that the buccal cusp had a buccolingual thickness of 3 mm measured at the height of contour. The palatal cusp was reduced to 1.5 mm coronal to CEJ. The specimens were prepared as follows:Group 1: resin composite restoration without horizontal self-threading pins or flowable composite (control group).Group 2: resin composite restoration without horizontal self-threading pins but with a 2 mm thickness of the flowable composite. Subsequent to thermocycling, all specimens were loaded to failure. The data were analyzed using a two-factor ANOVA test (α=0.05).The maximum mean of fracture resistance was in Group 1 (632.86 ± 119.46 N), and the minimum value was related to Group 3 (533.49 ± 168.07 N). There was not a statistically significant difference between the groups (p>0.05).Conclusion: Neither horizontal pin placement nor flowable composite had a significant effect on increasing the fracture resistance of endodontically-treated maxillary premolars restored with composite.

Vertical fracture resistance of endodontically treated teeth restored with four sets of obturation and filling materials

“…14 In this study, all teeth resisted much higher in vitro compressive forces than the normal masticatory forces (100e300 N) that might be exerted on maxillary premolars. 5 However, the force used in this study fundamentally differed in nature from masticatory forces. While natural forces change rapidly in type, magnitude, and direction, this force was a static compressive force that gradually increased until breakage occurred.…”

“…13 Moreover, considering their location in the dental arch, they are subjected to both compressive and shear forces. 5,21 Ultimately, they are also important to esthetics. 5 The composite resin obturation material, ResilonEpiphany, slightly increased the fracture resistance in both groups in which it was used, compared to those with gutta-percha-AH26.…”

“…5,21 Ultimately, they are also important to esthetics. 5 The composite resin obturation material, ResilonEpiphany, slightly increased the fracture resistance in both groups in which it was used, compared to those with gutta-percha-AH26. According to the probability value calculated by Tukey's HSD, this slight increase was not significant.…”

“…9,10 Furthermore, the accepted role of bonding agents in increasing the strength and resistance of a tooth to fractures due to the increase in tissue integrity was shown to be favorable. 5,9 This ability of bonding agents has inspired researchers to produce and evaluate similar materials and/or techniques for application in endodontics. 1 These include glass ionomer-and resin-based sealers.…”

The Effect of Composite Fiber Insertion along with Lowshrinking Composite Resin on Cuspal Deflection of Root-filled Maxillary Premolars

“…2 Based on the results of previous studies, endodontically-treated teeth can be restored with crowns, cast onlays, amalgam onlays or composite resins. 3,4 Recent developments in adhesive technology, offering new composites, have led to direct conservative restorations with high esthetic results. 3 The majority of light-cured composite resins used in dental procedures are based on dimethacrylate.…”