%0 Journal Article
%T In vitro evaluation of force degradation of elastomeric chains used in Orthodontics
%A Andr¨¦ Weissheimer
%A Arno Locks
%A Luciane Macedo de Menezes
%A Adriano Ferreti Borgatto
%J Dental Press Journal of Orthodontics
%D 2013
%I Dental Press Editora
%X OBJECTIVE: To analyze the in vitro force degradation of four different brands of elastomeric chains: American Orthodontics, Morelli, Ormco and TP Orthodontics. METHODS: The sample consisted of 80 gray elastomeric chains that were divided into four groups according to their respective manufacturers. Chain stretching was standardized at 21 mm with initial force release ranging from 300 g to 370 g. The samples were kept in artificial saliva at a constant temperature of 37¡ăC and the degradation force was recorded at the following time intervals: initial, 1, 3, 5, 7 and 9 hours, and 1, 7, 14, 21, 28, and 35 days. RESULTS: There was a statistically significant difference between the groups regarding the force degradation, mainly within the first day, as a force loss of 50-55% was observed during that time in relation to the initial force. The force delivered at 35 days ranged from 122 g to 148 g. CONCLUSION: All groups showed force degradation over time, regardless of their trademarks, a force loss of 59-69% was observed in the first hour compared to baseline. However, because the variation in force degradation depends on the trademark, studies such as the present one are important for guiding the clinical use of these materials. OBJETIVO: analisar, in vitro, a degrada  o de for a, ao longo do tempo, de elast meros das marcas comerciais American Orthodontics, Morelli, Ormco e TP Orthodontics. M¨¦TODOS: a amostra constituiu-se de 80 segmentos de elast meros em cadeia fechada na cor cinza, divididos em quatro grupos, conforme o fabricante. A distens o foi padronizada em 21mm, com libera  o de for a inicial variando de 300 a 370g de for a. As amostras foram mantidas em saliva artificial em temperatura constante de 37oC, e a for a avaliada nos seguintes intervalos: inicial, 1h, 3h, 5h, 7h, 9h, 1 dia, 7 dias, 14 dias, 21 dias, 28 dias e 35 dias. RESULTADOS: houve diferen a estatisticamente significativa na degrada  o de for a entre os grupos avaliados, sendo que no primeiro dia houve perda de 50 a 55% em rela  o ¨¤ for a inicial. Os valores m¨¦dios de for a em 35 dias variaram de 122 a 148g. CONCLUS O: todas as marcas comerciais apresentaram degrada  o de for a ao longo do tempo, sendo que na primeira hora a perda de for a esteve entre 59 e 69% da for a inicial. Por¨¦m, como existe varia  o dessa degrada  o dependendo da marca comercial, estudos como esses s o importantes para orienta  o do uso desses elast meros.
%K Elast meros
%K Resist¨ºncia ¨¤ tra  o
%K Materiais biom¨¦dicos e odontol¨®gicos
%K Elastomers
%K Shear bond strength
%K Biomedical and dental materials
%U http://www.scielo.br/scielo.php?script=sci_arttext&pid=S2176-94512013000100014