title: Retention force and fatigue strength of overdenture attachment systems.
abstract: This study evaluated retention force and fatigue resistance of two overdenture attachment systems. Twenty samples (O-ring and Bar-Clip) from two manufacturers (Conexão Sistemas de Prótese and Lifecore Biomedical) were prepared and divided into four groups: (i) Conexão/O-ring; (ii) Conexão/Bar-Clip; (iii) Lifecore/O-ring and (iv) Lifecore/Bar-Clip, with five samples in each group. They were submitted to mechanical fatigue test using a servohydraulic machine performing 5500 cycles of insertion and removal (f=0.8 Hz), immersed in artificial saliva. Retention force values were obtained three times (0, 3000 and after 5500 cycles) simulating the clinical service, using a tensile strength at 1 mm min(-1) and load cell of 1 kN. Data were analysed with analysis of variance and Tukey's test at 5% level. Results showed that Conexão/Bar-Clip specimens had significantly higher retention values than Lifecore/Bar-Clip (44.61 and 18.44 N, respectively), Conexão/O-ring specimens had significantly lower values than Lifecore/O-ring (13.91 and 19.75 N, respectively). Conexão/Bar-Clip values were always significantly higher than those of Conexão/O-ring group (44.61 and 13.91 N, respectively). Lifecore (O-ring and Bar-Clip) presented similar values (19.75 and 18.44 N, respectively). The systems evaluated showed satisfactory retention force values, before and after fatigue testing. Conexão/Bar-Clip specimens presented the highest values. A 5-year simulation of insertion and removal did not decrease retention values or fracture components.
authors.affiliation: Department of Prosthodontics and Periodontology, Piracicaba Dental School, University of Campinas, Piracicaba, Sao Paulo, Brazil.
authors.forename: D M
authors.initials: DM
authors.lastname: Botega
authors.forename: M F
authors.initials: MF
authors.lastname: Mesquita
authors.forename: G E P
authors.initials: GE
authors.lastname: Henriques
authors.forename: L G
authors.initials: LG
authors.lastname: Vaz
mesh_terms: D015921:Dental Implants; D003799:Dental Stress Analysis / Q000379:methods; D003779:Denture Design; D003781:Denture Retention; D003828:Denture, Overlay; D013718:Tensile Strength
chemical_list: D015921:Dental Implants