Reviewing work done in collaboration with Jennifer Hodgdon, we derive the most general crack growth law allowed by symmetry for mixed-mode three-dimensional fracture. We do so using the system developed in condensed matter physics to derive new laws that emerge on long length and time scales. In our derivation, we provide a symmetry interpretation for the three modes of fracture, we rederive th...

Failure of internal fixation following treatment of a fracture or fracture nonunion presents a challenging clinical situation. In certain cases, Ilizarov external fixation may be the preferred method to treat bony injuries that have failed to unite following one or more attempts at internal fixation. This paper reviews the modes of failure following internal fixation, revision internal fixation...

objectives: fracture strength is an important factor influencing the clinical long-term success of implant-supported prostheses especially in high stress situations like excessive crown height space (chs). the purpose of this study was to compare the fracture strength of implant-supported fixed partial dentures (fpds) with excessive crown height, fabricated from three different materials. mater...

BACKGROUND Supracondylar fracture of the humerus is the most common elbow injury that requires reduction and immobilization in the proper position to union. There are a few reports regarding the position of the forearm immobilization on elbow cosmetic outcome. OBJECTIVES This study aimed to compare two modes of the forearm, supination and pronation in elbow deformity incidence after closed re...

A research program on failure modes induced by spherical indenters in brittle layer structures bonded to polymeric substrates, in simulation of occlusal function in all-ceramic dental crowns, is surveyed. Tests are made on model flat and curved layers bonded onto a dentin-like polymer base, in bilayer (ceramic/polymer) and trilayer (ceramic/ceramic/polymer) configurations. All-transparent syste...

The aim of this study was to compare titanium-reinforced ZrO(2) and pure Al(2)O(3) abutments regarding their outcome after chewing simulation and static loading. Forty-eight standard diameter implants with an external hexagon were divided into three groups of 16 implants each and restored with three different types of abutments (group A: ZrO(2) abutments with titanium inserts; group B: Al(2)O(3...

BACKGROUND With the aim of developing methods that could increase the fracture resistance of structurally compromised endodontically treated teeth, this study was conducted to compare the effect of three esthetic post systems on the fracture resistance and failure modes of structurally compromised and normal roots. MATERIALS AND METHODS Forty five extracted and endodontically treated maxillar...

background: glass and quartz fiber posts are used in restoration of structurally compromised roots. accessory fiber posts are recently introduced to enhance the fiber post adaptation. this study evaluated the effectiveness of glass versus quartz accessory fiber posts. materials and methods: in this experimental study, 40 mandibular premolar roots with similar dimension (radius of 3.5 ± 0.2 mm a...