BACKGROUND Reversed shoulder arthroplasty is an accepted treatment for glenohumeral arthritis associated to rotator cuff deficiency. For most reversed shoulder prostheses, the baseplate of the glenoid component is uncemented and its primary stability is provided by a central peg and peripheral screws. Because of the importance of the primary stability for a good osteo-integration of the basepla...

background: the fi nal position of the abutment changes with the amount of tightening torque. this could eventually lead to loss of passivity and marginal misfi t of prostheses. the aim of this study was to evaluate the effect of three different tightening torques on the marginal adaptation of 3-unit cement-retained implant-supported fi xed dental prostheses (fdps). materials and methods: two i...

PURPOSE This study measured the gold screw preload at the gold cylinder-abutment screw joint interface obtained by 3 torque delivery systems. MATERIALS AND METHODS Using a precalibrated, strain-gauged standard abutment as the load cell, 3 torque delivery systems tested were shown to have significant differences in gold screw preload when a gold cylinder was attached. RESULTS Mean preloads m...

introduction: some clinicians use a handheld screw driver instead of a torque wrench to definitively tighten abutment screws. the aim of this study was to compare the removal torque of one-piece and two-piece abutments tightened with a handheld driver and a torque control ratchet. methods: 40 iti implants were placed in acrylic blocks and divided into 4 groups. in groups one and two, 10 iti one...

This study evaluated the influence of retorque on loosening torque (Lt) of prosthetic screws in implant-supported dentures with different fit levels. Ten mandibular implant-supported dentures were fabricated and then 20 cast models were then prepared using prosthetic structures to create 2 fit levels: passive fit (Pf) and misfit (Mf). Two tightening techniques were also evaluated: initial torqu...

In this paper, a modular designed automatic screw tightening shaft system, which is based on enhanced variable gain PID control, is proposed. Designed for the autonomous screw tightening operation, the screw tightening shaft enjoys huge potential for industry application. The screw tightening shaft and the screw tightening process are both mathematically modeled as an uncertain feedback system ...

This paper investigates the self-loosening of threaded fasteners subjected to dynamic shear load. Three kinds of typical coatings, PTFE, MoS2, and TiN applied to bolts and nuts, are tested in this investigation. The study experimentally examines the loosening mechanisms of fasteners and assesses the anti-loosening performance of the three tested coatings based on their tightening characteristic...

Spacely Sprockets (a pseudonym) specializes in the manufacture of aerospace products. The corporate mission of Spacely Sprockets is simply “client success”, which drives the expectation that every product must work the first time, every time. Spacely Sprockets relies on accurate application of torque when tightening mechanical fasteners during the manufacturing process. Torque is a twisting for...