Fracture resistance of posterior teeth restored with modern restorative materials

Abstract

We studied the fracture resistance of maxillary premolars restored with recent restorative materials. Fifty maxillary premolars were divided into five groups: Group 1 were unprepared teeth; Group 2 were teeth prepared without restoration; Group 3 were teeth restored with tetric ceram HB; Group 4 were teeth restored with InTen S; and Group 5 were teeth restored with Admira. The samples were tested using a universal testing machine. Peak loads at fracture were recorded. The teeth restored with Admira had the highest fracture resistance followed by those restored with InTen-S and tetric ceram HB. Prepared, unrestored teeth were the weakest group. There was a significant difference between the fracture resistance of intact teeth and the prepared, unrestored teeth. There was also a significant difference among the tested restorative materials. Teeth restored with Admira showed no significant difference when compared with the unprepared teeth. It was concluded that the teeth restored with Admira exhibited the highest fracture resistance.

Impacts of Contracted Endodontic Cavities on Instrumentation Efficacy and Biomechanical Responses in Maxillary Molars

“…Endodontic cavities were restored with bonded composite resin to simulate clinical function and to facilitate loading. Filling of cavities with bonded composite resin may restore fracture strength of teeth to levels between 55% and 72% of the strength values of intact teeth (85). The restored molars were fatigued with cyclic loading to better simulate dentin fractures in root-filled teeth that are considered to be a fatigue process leading to micro-defects within tooth structure and at restoration-tooth interfaces (103,104,(113)(114)(115).…”

“…Composite resins adhere to tooth structure using micromechanical retention of resin tags in "etched" enamel rods and in the hybridized layer of dentin (82). In the short term, bonded composite resin restorations of the endodontic cavity may partially or totally reverse the reduction in fracture strength imparted by the endodontic cavity (46,65,(83)(84)(85)(86). However, the long-term stability of dentin bonding is subject to degradation (87).…”

“…The stress generated for a given force is inversely proportional to the cross-sectional area over which the force is applied and can thus influence the results when measuring the force at which fracture occurs (74). Studies commonly use a spherical cross-head with a diameter of approximately 5 mm when assessing fracture strength of teeth (73,85,118), while use of different sizes have also been reported (74).…”

“…Our previous results regarding the impacts of CEC in maxillary incisors and mandibular premolars and molars (46), might not be extrapolated to maxillary molars where the morphology is distinctly different. Also, data on fracture resistance of maxillary molars appear to be sparse (119) unlike data on mandibular molars (46,73,74,85,86,118). Therefore, the aim of this in-vitro study was to assess the impacts of CEC in maxillary molars with respect to:…”

Fracture strength of teeth with access cavity preparation with operating microscope or on buccal surfaces

“…The procedure managed to restore the lost structure, to seal the root canal, and to strengthen the remaining dental structure [20,21]. Restoration of the access cavity in posterior teeth after endodontic treatment can increase fracture strength by up to 72% when compared to healthy teeth [15,22]. Krishan et al decided not to use such restorations since they thought some variables could be biased.…”