The Effect of Polymerization Cycles on Color Stability of Microwave-Processed Denture Base Resin


Autoria(s): BONATTI, Marilia Rodrigues; CUNHA, Tatiana Ramirez; REGIS, Romulo Rocha; SILVA-LOVATO, Claudia Helena; PARANHOS, Helena Freitas Oliveira; SOUZA, Raphael Freitas de
Contribuinte(s)

UNIVERSIDADE DE SÃO PAULO

Data(s)

19/10/2012

19/10/2012

2009

Resumo

Purpose: This study evaluated the effect of different microwave polymerization cycles on the color changes of a microwave-processed denture base resin after accelerated aging and immersion in beverages. Materials and Methods: Specimens of light pink acrylic resin were divided into three groups according to polymerization cycle: (A) 500 W for 3 minutes, (B) 90 W for 13 minutes + 500 W for 90 seconds, and (C) 320 W for 3 minutes + 0 W for 4 minutes + 720 W for 3 minutes. Control groups were a heat-processed acrylic resin (T) and a chemically activated denture repair resin (Q). Eight specimens per group were aged in an artificial aging chamber and evaluated at 20, 192, and 384 hours. Another series of 40 specimens per group were immersed in water, coffee, tea, cola, or red wine and evaluated at 1, 12, and 36 days. Color was measured by a spectrophotometer before and after aging or immersion. Color changes (Delta E) were analyzed by ANOVA/Bonferroni t-test (alpha = 0.05). Results: Mean Delta E (+/- SD) after 384 hours of accelerated aging were (A) 2.51 +/- 0.50; (B) 3.16 +/- 1.09; (C) 2.89 +/- 1.06; (T) 2.64 +/- 0.34; and (Q) 9.03 +/- 0.40. Group Q had a significantly higher Delta E than the other groups. Color changes of immersed specimens were significantly influenced by solutions and time, but the five groups showed similar values. Mean Delta E at 36 days were (water) 1.4 +/- 0.8; (coffee) 1.3 +/- 0.6; (tea) 1.7 +/- 0.5; (cola) 1.4 +/- 0.7; and (red wine) 10.2 +/- 2.7. Results were similar among the five test groups. Conclusions: Color changes of the microwave-polymerized denture base resin tested were not affected by different polymerization cycles after accelerated aging or immersion in beverages. These changes were similar to the conventional heat-polymerized acrylic resin test, but lower than the repair resin after accelerated aging.

University of Sao Paulo (USP)[2006.1.24397.1.3-ProIP]

National Council for Scientific and Technological Development (CNPq)[2007.1.296.58.7-PIBIC]

Identificador

JOURNAL OF PROSTHODONTICS-IMPLANT ESTHETIC AND RECONSTRUCTIVE DENTISTRY, v.18, n.5, p.432-437, 2009

1059-941X

http://producao.usp.br/handle/BDPI/26369

10.1111/j.1532-849X.2009.00458.x

http://dx.doi.org/10.1111/j.1532-849X.2009.00458.x

Idioma(s)

eng

Publicador

WILEY-BLACKWELL

Relação

Journal of Prosthodontics-implant Esthetic and Reconstructive Dentistry

Direitos

restrictedAccess

Copyright WILEY-BLACKWELL

Palavras-Chave #Accelerated aging #acrylic resins #beverages #color stability #coloring agents #denture bases
Tipo

article

original article

publishedVersion