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

Autor(es)

Farina, Ana Paula ^[1] ; Spazzin, Aloisio Oro ^[1] ; Costa Nunez Pantoja, Juliana Maria ^[1] ; Xediek Consani, Rafael Leonardo ^[1] ; Mesquita, Marcelo Ferraz ^[1]

Afiliação do(s) autor(es)

^[1] Univ Estadual Campinas, Piracicaba Dent Sch, Dept Prosthodont & Periodont, BR-13414903 Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: INTERNATIONAL JOURNAL OF ORAL & MAXILLOFACIAL IMPLANTS; v. 27, n. 4, p. 833-838, JUL-AUG 2012.
• Citações Web of Science: 13

Resumo

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)

• Processo FAPESP: 09/51423-3 - Efeito da ciclagem mecanica, do material, e do retorque de parafusos, na sua estabilidade em proteses multiplas sobre implantes com dois niveis de desajuste.
• Beneficiário: Marcelo Ferraz Mesquita
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 09/02306-4 - Efeito da ciclagem mecânica, do material, e do retorque de parafusos, na sua estabilidade em próteses múltiplas sobre implantes com dois níveis de desajuste.
• Beneficiário: Ana Paula Farina
• Modalidade de apoio: Bolsas no Brasil - Doutorado