screw-retained implant restorations have an advantage of predictable retention as well as retrievability, and obviate the risk of excessive sub-gingival cement commonly associated with cement retained implant restorations. screw-retained restorations generally have screw access holes, which can compromise esthetics and weaken the porcelain around the holes. the purpose of this study is to descr...

The intralaminar screw construct has been recently introduced in C6-C7 fixation. The aim of the study is to compare the stability afforded by three different C7 posterior fixation techniques using a three-dimensional finite element model of a C6-C7 cervical spine motion segment. Finite element models representing three different cervical anchor types (C7 intralaminar screw, C7 lateral mass scre...

To compare the mechanical effectiveness of a new conical screw design with a conventional cylindrical screw design, the screw insertion time, torque, and pull-out strength of single-pedicle screw and triangulated-pedicle screw constructs of each type of screw were compared in human cadaveric vertebral bodies. The time required to insert the conical screws was less than that required for cylindr...

STUDY DESIGN Pedicle screw strength or load to failure was biomechanically evaluated, and the geometric characteristics of pedicle screw instrumentation systems were compared. OBJECTIVES To compare the features of pedicle screw systems, and to demonstrate the failure point of the polyaxial pedicle screw head. SUMMARY OF BACKGROUND DATA Many pedicle screw instrumentation systems are currentl...

Shallow notch-screw connections, which showed potential superior slip moduli and load-carrying capacity compared with the traditional screwed connections can be employed in timber-concrete composite (TCC) floors were examined this study. Eight groups of shallow designed to perform push-out tests, arrangement screws, heavy timber types, width notch considered. The depth was uniformly 15 mm. vert...

1. Introduction Adjacent segment degeneration (ASD) has been reported as the one of late serious complication after spinal fusion surgery [1-3]. Presumably, the immediate rigidity produced by instrumentation causes more stress leading to accelerated degeneration at adjacent levels [2]. Many previous studies have been corroborated a trend toward earlier development of ASD with instrumentation as...

BACKGROUND Efforts to select the appropriate number of implants in adolescent idiopathic scoliosis (AIS) instrumentation are hampered by a lack of biomechanical studies. The objective was to biomechanically evaluate screw density at different regions in the curve for AIS correction to test the hypothesis that alternative screw patterns do not compromise anticipated correction in AIS when using ...

there have been a number of developments in screw design and implantation techniques over recent years, including proposal of an alternative trajectory entitled as cortical bone trajectory (cbt). cortical bone trajectory has been investigated in recent medical treatments as an alternative for screw fixation aimed at increasing purchase of pedicle screws in higher density bone. cbt screw inserti...