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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

An In Vitro Comparison of Joint Stability of Implant-Supported Fixed Prosthetic Suprastructures Retained with Different Prosthetic Screws and Levels of Fit Under Masticatory Simulation Conditions

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Author(s):
Farina, Ana Paula [1] ; Spazzin, Aloisio Oro [1] ; Costa Nunez Pantoja, Juliana Maria [1] ; Xediek Consani, Rafael Leonardo [1] ; Mesquita, Marcelo Ferraz [1]
Total Authors: 5
Affiliation:
[1] Univ Estadual Campinas, Piracicaba Dent Sch, Dept Prosthodont & Periodont, BR-13414903 Sao Paulo - Brazil
Total Affiliations: 1
Document type: Journal article
Source: INTERNATIONAL JOURNAL OF ORAL & MAXILLOFACIAL IMPLANTS; v. 27, n. 4, p. 833-838, JUL-AUG 2012.
Web of Science Citations: 13
Abstract

Purpose: This study sought to determine an optimal postinsertion retorque protocol to maintain implant-suprastructure joint stability after being subjected to a 1-year in vitro masticatory simulation. Materials and Methods: Ten mandibular implant-supported dentures were manufactured and 20 epoxy resin models were obtained for two fit levels: passive fit and misfit. Eight groups (n = 20) were created on the basis of vertical fit (passive or misfit) and prosthetic screw material (titanium or gold). The single-screw test was performed and the vertical misfit was quantified using an optical microscope. Loosening torque was measured after simulations of two types of clinical use: (1) 6 months of use, torque loosening, retightening, another 6 months of use, and loosening torque; and (2) 1 year of use followed by loosening torque. Data were analyzed by means of two-way analysis of variance and the Tukey test. Results: The factors of cycling time and condition use (fit level and screw type), as well the interaction between these factors, significantly influenced the loosening torque (P < .05). After 6 months and another 6 months of clinical use simulation, titanium screws showed higher loosening torque values than did gold screws for the same fit level (P < .05). After 1 year of clinical use simulation, titanium and gold screws in passively fit dentures showed higher loosening torque values than they did in misfit dentures (P < .05). The titanium screws presented a decrease in the loosening torque after 1 year in misfit dentures. Conclusions: The stability of titanium screws was higher than that of gold screws after 6 months of simulation because of their lower plastic deformation. When the cycling time was analyzed, titanium screws were less stable after 1 year of simulation because of loss of torque in the presence of misfit. INT J ORAL MAXILLOFAC IMPLANTS 2012;27:833-838. (AU)

FAPESP's process: 09/02306-4 - Effect of mechanical cycling, material and screw retorque, on stability in multiple implant supported prosthesis with two misfit levels.
Grantee:Ana Paula Farina
Support Opportunities: Scholarships in Brazil - Doctorate