The aim of this study was to investigate whether endodontically retreated teeth filled with Resilon are more resistant to fracture than those filled with guttapercha following hand or rotary removal techniques. Seventy-two upper anterior human teeth were selected, decoronated and reduced to 12 mm. The canals were shaped using rotary ProTaper files and randomly assigned into two groups (n=36). O...

S E On the Fracture Toughness of Advanced Materials A R C H By Maximilien E. Launey, and Robert O. Ritchie* N E W S Few engineering materials are limited by their strength; rather they are limited by their resistance to fracture or fracture toughness. It is not by accident that most critical structures, such as bridges, ships, nuclear pressure vessels and so forth, are manufactured from materia...

AIM The aim of this in vitro study was to compare the fracture resistance of endodontically-treated anterior teeth with their roots reinforced using three different restorative methods. METHODS AND MATERIALS Forty sound maxillary human central incisors were randomly assigned to four groups (n=10). The crowns of the teeth were removed at a level 2 mm incisal to the cementoenamel junction (CEJ)...

Aim Comparative evaluation of the fracture resistance of maxillary premolar teeth restored with two high-viscosity bulk-fill composites and incrementally placed composite. Materials and Methods Seventy-five freshly extracted maxillary premolar teeth were selected. Fifteen specimens served as positive control (Group 1). Mesio-occluso-distal cavity preparation was prepared on the rest of the sp...

This study evaluated the effects of 10% alphatocopherol on the fracture resistance of endodontically treated teeth subjected to tooth bleaching with hydrogen peroxide and immediately restored with composite resin. Fifty bovine incisors were selected, including 10 sound teeth that constituted the control group (G1 (C)). The remaining 40 teeth, which were endodontically treated, were divided into...

AIM The aim of this study was to evaluate the fracture resistance of simulated immature teeth, when the root canals were completely filled either with mineral trioxide aggregate (MTA) or Biodentine, comparing with that of roots filled with apexification procedure. MATERIALS AND METHODS Sixty mandibular premolar teeth with single, straight canals decoronated at cementoenamel junction were divi...

The aim of this study was to compare the vertical fracture resistance of roots obturated with different root canal filling materials and sealers. Crowns of 55 extracted mandibular premolar teeth were removed to provide root lengths of 13 mm. Five roots were saved as negative control group (canals unprepared and unfilled). Fifty root canals were instrumented and then five roots were saved as pos...

BACKGROUND AND AIMS The aim was to evaluate the effect of three methods of fiber insertion on fracture resistance of root-filled maxillary premolars in vitro. MATERIALS AND METHODS Sixty extracted human maxillary premolars received endodontic treatment followed by preparation of mesioocclusodistal (MOD) cavities, with gingival cavosurface margin 1.5 mm coronal to the cementoenamel junction (C...

With only 1% protein by weight, tooth enamel is the most highly mineralized tissue in mammals. The focus of this study was to evaluate contributions of the proteins on the fracture resistance of this unique structural material. Sections of enamel were obtained from the cusps of human molars and the crack growth resistance was quantified using a conventional fracture mechanics approach with comp...