Avaliação Comparativa da Perda de Retenção de Attachments do Tipo Barra/Clipes Usados em Overdentures
Comparative evaluation of retention loss of bar/clips attachments for Overdentures
Freitas, R.; Vaz, L.G.; Pedreira, A.P.R.V.
Rev. odontol. UNESP, vol.32, n2, p.113-118, 2003
Resumo
Objetivou-se avaliar a perda de retenção sofrida por dois modelos de Attachments para Overdentures do tipo barra/clipe, marcas Conexão® Sistemas de Prótese e Sterngold Implamed® do Brasil, durante 5 anos de uso simulado, utilizando-se um e 2 clipes sobre a barra. As barras foram fixadas a 2 análogos Standard posicionados sobre um modelo de aço. Os clipes foram capturados sob 40 bases de overdentures e submetidos à ciclagem mecânica na máquina de ensaios mecânicos Material Test System 810, velocidade de deslocamento vertical de 2 mm/min, freqüência 2 Hz, amplitude 0,3 mm e 5.400 ciclos. O teste estático de resistência ao deslocamento foi realizado em intervalos de tempo pré-estabelecidos (inicial, 6 meses, um a 5 anos) entre os períodos de ensaio dinâmico realizados na mesma máquina. Utilizou-se Análise de Variância e Teste de Tukey, p < 0,05. Ambos os grupos perderam retenção ao longo do experimento, sem diferença estatisticamente significante entre os intervalos de tempo analisados. A resistência média inicial à remoção variou de 6,4 N (Sterngold Implamed/2 clipes) a 55,2 N (Conexão/2 clipes), e a final entre 1,9 N (Sterngold Implamed/1 clipe) a 42,6 N (Conexão/2 clipes). Nenhum attachment sofreu perda total de sua retentividade.
Palavras-chave
Sobredentaduras, encaixes, retenção
Abstract
The aim of this study was to evaluate the retention loss of two plastis bar-clip overdenture attachments systems from Conexão® and Sterngold Implamed® do Brazil, throughout five years of simulated function with one and two clips upon the bar. The bars of both systems were fixed on two Standard analogues, upon a steel laboratory cast. Forty overdentures saddles were made. Each bar-clip assembly was subjected to 5,400 insertion and removal cycles in the Material Test System 810, with a 2 mm/min cross-speed, 2 Hz frequency and 0.3 mm amplitude. The strenght dislodgement static test was performed in database, six months and one to five years, among the dinamic test perfomed in the same machine. Data were subjected to Analysis of Variance and Tukey test, p < 0.05. Retention decreased over the course of consecutive pulls for all the attachments, with no statistically significant diference among the periods analysed. The initial strenght dislodgement resistance average varied from 6.4 N (Sterngold Implamed®/2 clips) to 55.2 N (Conexão®/2 clips) and the final average varied from 1.9 N (Sterngold Implamed®/1 clip) to 42.6 N (Conexão®/2 clips). All the attachments showed residual retentiveness at the final of the test.
Keywords
Overdentures, attachments, retention
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