Effect of accelerated ageing on the permanet deformation and tensite bond strenght of auto-polymerizing soft dentures liners / Efeito de tempos de simulação do intemperismo natural na deformação permanente dos materiais reembassadores resilientes e na resitencia a tração da sua união com a resina acrilica

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

This study aimed to evaluate the effect of different times of accelerated ageing over the properties of permanent deformation and tensile bond strength of two soft liners used on prostheses relining. The soft liners studied were auto-polymerizing and acrylic resin and silicone based. The materials were processed according the manufacturers instructions. The resilient liner specimens (9 X 9 X 3 mm) for tensile bond strength were processed between 2 acrylic resin blocks (9 X 9 X 40 mm). The resilient liner specimens for permanent deformation test were 19 mm height and 12.7 mm diameter. The specimens (n=10) were submitted to accelerated ageing process during 2, 4, 8, 16, 32 and 64 cycles. Tensile bond strength was performed with crosshead speed of 5 mm/min using a testing machine EMIC DL-500 MF. Permanent deformation was performed with an apparatus described on specification no 18 of A.D.A., with compressive load of 750 gf. Statistical analysis was performed using Kruskall-Wallis and Dunn tests to compare materials on the same ageing period and Mann-Whitney test to compare the effect of different ageing periods on each material. The results obtained after statistical analysis demonstrated that the silicone based reliner presented lower percentage of permanent deformation (p<0.0001) and higher tensile bond strength (p<0.0001) than the acrylic resin based reliner in all the ageing intervals. And that the accelerated ageing process did not affect the permanent deformation (p=0.90) and tensile bond strength (p=0.15) of the silicone based reliner, but reduced the percentage of permanent deformation and increased tensile bond strength of the acrylic resin based reliner (p<0.05). Results demonstrated that silicone based reliner is less susceptible to compressive loads, presenting better elastic recovery, lower permanent deformation and higher tensile bond strength. And that accelerated ageing affected only acrylic resin based reliners

ASSUNTO(S)

compressive strength denture liners resistencia a tração elasticity resinas acrilicas tensile strength força compressiva reembasadores de protese dentaria elasticidade acrylic resins

ACESSO AO ARTIGO

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