Color stability of resin and silicone is an important factor for longevity of facial prostheses. The aim of this study was to evaluate the color stability of resins and silicone for facial prostheses. Three brands of acrylic resin and 1 of facial silicone were evaluated considering pigment incorporation for the colorless materials. Ten samples of each material were fabricated and submitted to measurements of chromatic alteration initially and after 252, 504, and 1008 hours of weathering through visual analysis and spectrophotometry. Data were evaluated by analysis of variance and Tukey test (P < 0.05). Results showed a statistically significant difference in color alteration among materials independent of aging. According to visual analysis, the color difference between pigmented and colorless Silastic MDX4-4210 and between pigmented and colorless Classico acrylic resin was statistically significant for the 3 weathering periods. Aging for 1008 hours represented a significant influence on color alteration of all resins. All materials presented chromatic alteration after accelerated artificial aging.
The ceramic pigment presented greater color stability regardless of disinfection and period. On the other hand, the makeup pigment exhibited the highest values of chromatic alteration.
Abstract. The use of photoelastic analysis contributes to the rehabilitation of patients with oral-sinus-nasal sequelae, which in turn affect important functions such as chewing, swallowing, and speech. The prosthetic rehabilitation with implant-retained dentures is a suitable treatment option. The purpose of this study was to verify, by using a photoelastic analysis, the stress distribution in implant-retained palatal obturator dentures (relined or not) associated with different attachment systems (O-ring, bar-clip, and bar-clip associated with distally placed O-rings). Two photoelastic models were obtained from an experimental maxillary cast presenting an oral-nasal communication.One model had two 13-mm length implants placed on the left region. A total of eight colorless maxillary obturators were fabricated and subsequently four of them were relined with soft silicone soft, and three had attachment systems associated. The assembly (model/attachment system/prosthesis) was positioned in a circular polariscope and a 100-N load was applied at 10 mm∕s. The results showed that the denture relining influenced the distribution and amount of stress on the models. The O-ring group displayed the lowest stress levels, followed by bar-clip system associated with distally placed O-rings and bar-clip groups.
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