Effects Of Red-oxide Pigment On The Color Stability And Morphology Of Maxillofacial Silicone Prosthesis

Objective:The purpose of this study was to investigate the effect of sun-light on the color stability of maxillofacial silicone prosthesis, and to analyse the microstructure change of elastomer combined with fillers.Materials and Methods:Firstly, the components of elastomer prosthesis were divided into three groups:silicone (colloid); pigment (red ferric oxide); opacifier (nano-TiO2:silane coupling agent KH570-treatment). Five specimens of each group were tested, fifteen samples in all. Secondly,0.01wt% red ferric oxide/nano-TiO2 were separately added to the silicone, uniformly mixed, five specimens of each group for a total of twenty specimens divided into four groups (silicone added red ferric oxide/silicone added nano-TiO2/silicone added both, silicone with nothing as the control group). All the specimens in each part were submitted to simulated sun-light for 34.28h. The CIELAB color values were calculated by DeltaE* using spectrophotometer and the microstructure chang was evaluated under EPMA..Results:In part one:After accelerated aging for 34.28h, the silicone had the significant color change among the components of elastomer prosthesis, followed by red ferric oxide, nano-TiO2. The values ofâ–³E were seperately 2.22/0.73/0.44, and there existed significantly statistical difference among three groups; The change of CIELAB was unidentical, the value of L* for nano-TiO2 lowest, the value of a* red ferric oxide lowest, and the value of b* for all the three components increased. Under gross obsersation, all the components more yellow, and silicone appeared obvious change. In part two:After exposure 34.28h of the energy for 300W, the control group for silicone with nothing had the most color change, followed by silicone added nano-TiO2, silicone added red ferric oxide, silicone added both, their values ofâ–³E were seperately 2.22/1.94/1.49/1.12, the groups for silicone and silicone with both, silicone added nano-TiO2 and silicone added both had sinificantly statistical difference, the other groups were not significantly different from each other. Observed from the microstructure by EPMA, the groups added fillers were dramatically different from the control group-silicone.Conclusion:1. Silicone had the most color change, and not accepted in clinical2. After adding the fillers to silicone, there existed an harmony effect on the color stability of elastomer prosthesis between red-oxide and nano-TiO2. To some extent, red-oxide had more advanced UV resistance than nano-TiO2.3. Concentration of fillers affected the color stability of maxillofacial silicone elastomer prosthesis.4. Fillers could enhance the physical and mechanical properties, meanwhile also changed the microstructrue of silicone.