title: [Comparative evaluation of retention loss in four types of attachments used on overdentures in function of time of use].
abstract: The aim of this study was to evaluate and compare the retentive capacity between two O-ring and O-SO system (Group I), and two ERA system types - white and gray retention caps - (Group II), respectively, in simulated function in database, 6 months, 1, 2, 3, 4, and 5 years later, with insertion and removal cycles. Two Brånemark implants were fixed in two trapezoidal metallic bases for the tests. Removal and insertion tests were done in a sewing machine, adjusted for this purpose using a belt and a pulley system, moving a steel crankshaft. A delineator platinum hold was used for body trial fixation to the metallic base of the sewing machine. Resistance test to axial movement of the caps by tension was done in a Universal test machine in an established period of time, before and after the cycle accomplishments in the adapted sewing machine. Based on the results, this study concludes that all the attachment systems tested showed retention loss during the experiment; the ERA system showed, since the beginning, higher retention compared to the other systems and the gray colored attachment showed the best result in the end of the simulated use test.
authors.affiliation: Departamento de Prótese, Faculdade de Odontologia de Bauru, Universidade de São Paulo.
authors.forename: Wellington Cardoso
authors.initials: WC
authors.lastname: Bonachela
authors.forename: Ana Paula Ribeiro do Vale
authors.initials: AP
authors.lastname: Pedreira
authors.forename: Luciana
authors.initials: L
authors.lastname: Marins
authors.forename: Tatiana
authors.initials: T
authors.lastname: Pereira