Track topics on Twitter Track topics that are important to you
Objectives: The aim of this study was to evaluate the variation in removal torque of implant prosthetic abutment screws after successive tightening and loosening cycles, in addition to evaluating the influence of the hexagon at the abutment base on screw removal torque. Material and methods: Twenty hexagonal abutments were tightened to 20 regular external hex implants with a titanium alloy screw, with an insertion torque of 32 N cm, measured with a digital torque gauge. The implant/abutment/screw assemblies were divided into two groups: (1) abutments without hexagon at the base and (2) abutments with a hexagon at the base. Each assembly received a provisional restoration and was submitted to mechanical loading cycles. After this, the screws were removed and the removal torque was measured. This sequence was repeated 10 times, then the screw was replaced by a new one, and another cycle was performed. Linear regression analysis was performed. Results: Removal torque values tended to decrease as the number of insertion/removal cycles increased, for both groups. Comparisons of the slopes and the intercepts between groups showed no statistical difference. There was no significant difference between the mean values of last five cycles and the 11th cycle. Within the limitations of this in vitro study, it was concluded that (1) repeated insertion/removal cycles promoted gradual reduction in removal torque of screws, (2) replacing the screw with a new one after 10 cycles did not increase resistance to loosening, and (3) removal of the hexagon from the abutment base had no effect on the removal torque of the screws. To cite this article: Cardoso M, Torres MF, Lourenço EJV, de Moraes Telles D, Rodrigues RCS, Ribeiro RF. Torque removal evaluation of prosthetic screws after tightening and loosening cycles: an in vitro study. Clin. Oral Impl. Res. xx, 2011; 000-000. doi: 10.1111/j.1600-0501.2011.02165.x.
Department of Prosthodontics, Dental School, State University of Rio de Janeiro, Rio de Janeiro, Brazil Department of Dental Materials and Prosthodontics, Dental School of Ribeirão Preto, University of São Paulo, São Paulo, Brazil.
This article was published in the following journal.
Name: Clinical oral implants research
The purpose of this study was to evaluate the influence of tightening technique and the screw coating on the loosening torque of screws used for Universal Abutment fixation after cyclic loading.
Polyaxial locking screws are increasingly applied in fracture fixation. To investigate the durability of the head-locking mechanism, the removal torque of variable angle (VA) and fixed angle (FA) stai...
The high-performance polymer PEEK (poly-ether-ether-ketone) is more and more being used in the field of dentistry, mainly for removable and fixed prostheses. In cases of screw-retained implant-support...
There is a lack of organization in existing studies on the outcome and complications of total shoulder arthroplasty. As a result, it is difficult to gain substantial evidence regarding the rate and ri...
Time-elapsed analysis of bone is an innovative technique that uses sequential image data to analyze bone mechanics under a given loading regime. This paper presents the development of a novel device c...
The purpose of this study is to evaluate a new prosthetic socket construction technique in order to improve the quality of care to lower extremity amputees.
Chronic pain following surgical stabilization of a pelvic fracture is very prominent and can have a major affect on a patient's quality of life. Persistent pain after radiographic evidence...
The purpose of this research study is to evaluate effectiveness of a non-ablative (does not remove skin) treatment for cellulite (dimpled fat) in conjunction with skin tightening using the...
The total hip replacement, with over 120,000 cases per year in France, provides short term, excellent functional results and a significant improvement in quality of life, in almost all cas...
The objective of this study is to evaluate arm rejuvenation and tightening with a nanofractional radiofrequency device, Venus viva, Venus concept, Toronto Canada. We recruit 20 subjects. A...
Removal of an implanted therapeutic or prosthetic device.
Removal of bone marrow and evaluation of its histologic picture.
Studies determining the effectiveness or value of processes, personnel, and equipment, or the material on conducting such studies. For drugs and devices, CLINICAL TRIALS AS TOPIC; DRUG EVALUATION; and DRUG EVALUATION, PRECLINICAL are available.
Studies designed to assess the efficacy of programs. They may include the evaluation of cost-effectiveness, the extent to which objectives are met, or impact.
Dentistry is the study, management and treatment of diseases and conditions affecting the mouth, jaw, teeth and their supporting tissues (Oxford Medical Dictionary) The work of a dentist ranges from regular patient check-up to orthodontics and surgery....