Several key fracture-mechanics parameters associated with the onset of subcritical and critical cracking, specifically the fracture toughness, crack-resistance curve, and fatigue threshold, have recently been reported for the superelastic alloy Nitinol, in the product form of the thin-walled tube that is used to manufacture several biomedical devices, most notably endovascular stents. In this s...

Endodontic treatment makes the tooth brittle due to loss of bulk of tooth structure, decrease in the moisture content of dentin and dentin elasticity. The following study was carried out to evaluate the effect of endodontic treatment on the fracture resistance of the tooth and reinforcing ability of three different core materials. The following study comprised of sample size of 30 deciduous sec...

AIM To determine whether patient age contributed to the fracture resistance of teeth subjected to root canal treatment and post placement. METHODOLOGY Forty-five single-rooted, single-canal human teeth were mounted, instrumented, obturated and prepared for a post. The teeth were divided into young (18 < or = age < or = 35) and old (60 < or = age) groups and subjected to cyclic loading until f...

OBJECTIVE The aim of this study was to assess the resistance of fracture of mesio-occlusal-distal (MOD) ceramic inlays and composite fillings in premolars and to compare fracture modes between the groups. MATERIAL AND METHODS Twenty seven extracted intact human premolars were selected and divided into three groups: I - intact teeth (control group), II - MOD cavities restored with indirect cer...

The purpose of this study is to evaluate the fitting accuracy and fracture resistance of crowns using a hybrid zirconia frame made of both porous and dense zirconia. Commercial semi-sintered zirconia, sintered dense zirconia and sintered hybrid zirconia were used. Sintered zirconia was milled using the CAD/CAM system, and semi-sintered zirconia was milled and sintered to fabricate molar crown f...

This study investigated the effect of fiber reinforced composite resin (FRC) post lengths, ferrule, and full coverage metal crown on fracture resistance of endodontically treated teeth (ETT) using an experimental FRC post with the similar elastic modulus of dentin (11.5 GPa). ETT was restored according to 1 of 7 combinations of FRC post length (10, 5, 2.5, 0 mm), ferrule (0, 2 mm), and with/wit...

OBJECTIVE The aim of this study was to compare the fracture resistance of roots obturated with different materials. STUDY DESIGN Sixty root canals were instrumented and divided into 4 equal groups (n = 15 each). The root canals in group 1 were filled with AH26 sealer and gutta-percha, in group 2 with Resilon and Epiphany, and in group 3 with Ketac-Endo Aplicap and gutta-percha. Fifteen root c...

The effect of the die materials on the fracture strength of CAD/CAM monolithic ceramic crowns was studied in this research. Three different types of die materials (dentin, Ni-Cr alloy, epoxy resin) were prepared. The monolithic crowns were fabricated using a CAD/CAM System; CEREC 4. The CAD/CAM crowns were cemented to dies using a resin cement. The specimens were tested under compressive load a...

PURPOSE The aim of this study was to evaluate the fracture resistance and fracture behavior of monolithic zirconia crowns in accordance with the preparation design and aging simulation method. MATERIALS AND METHODS An upper first molar was prepared sequentially with three different preparation designs: shoulderless preparation, 0.4 mm chamfer and 0.8 mm chamfer preparation. For each preparati...

AIM The aim of this study was to investigate the fracture strength of three post systems cemented with a dual cure composite resin luting cement by using different adhesive systems. METHODS AND MATERIALS In this study 63 extracted anterior teeth with single roots were endodontically prepared and filled. Teeth were randomly assigned to one of three post systems placed into the prepared canals:...