Novel Ball Head Screw and Screwdriver Design for Implant-Supported Prostheses With Angled Channels: A Finite Element Analysis

Abstract

The primary objective of this study was to design the optimal geometry of a novel screwdriver; create the grooves on a ball head screw; and demonstrate its resistance to a torque of up to 40 Ncm at an angulation of 0, 15 and 30 degrees by using nonlinear finite element analysis. A secondary objective was to create a fool-proof and easily recognizable system. The grooved ball head screw and geometry of the screwdriver, functioning from an angulation of 0° to 30°, was generated using Pro-ENGINEER Wildfire 5.0 software. Static structural analyses between bodies in contact were performed at different angles of 0°, 15° and 30° at a torque of 20 Ncm and 40 Ncm, using nonlinear finite element simulation by means of ANSYS 12.0. The maximum stress supported by the ball head screw and screwdriver was similar at 20 Ncm and 40 Ncm. Although greater deformations were found at 40 Ncm, these were small and might not affect the performance of the system. Besides, the rupture torque value for the M2 connection was 55 Ncm for 0° and 30°, and 47.5 Ncm for 15°. Numerical simulation showed that the ball head system design can achieve the mechanical strength requirements expected for screws used in implant-supported restorations at an angulation of up to 30°. Finite element analysis showed this novel ball head screw and screwdriver system to be a good solution for angled screw channels in implant-supported prostheses.

Clinical and Laboratory Outcomes of Angled Screw Channel Implant Prostheses: A Systematic Review

“…However, significantly lower output torque transmission to abutment screws was found when the angulation increased to 25 and 28 degrees. Furthermore, photography of the specimens revealed evidence of wear at the screw head 40 Chen and Pan 41 Guljé et al 42 Hotinski and Dudley 43 Lin et al 30 Menéndez-Collar et al 44 Mokhtarpour et al 45 Paolantoni et al 46 Vélez et al 47 Edmondson et al 11 González-Martín and Veltri 48 Farré-Berga et al 49 Farronato et al 50 Wang et al 51 Abbreviation: ASC, angled screw channel.…”

Types of retention for implant-supported fixed prosthesis: a narrative literature review

“…A taxa de complicações da utilização do parafuso angulado se mostrou similar àquelas observadas com o sistema convencional de retenção por parafuso nos casos acompanhados por cerca de um ano 36 . Apesar de resultados iniciais promissores, faltam na literatura estudos que analisam a perda de torque a longo prazo, assim como ensaios randomizados e controlados para avaliar a eficiência in vivo desse tipo de sistema com maior tempo de acompanhamento e das variações intra-sistema encontradas.…”