Ultraviolet radiation-induced color shifts occurring in oil-pigmented maxillofacial elastomers (original) (raw)
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Color changes in dry-pigmented maxillofacial elastomer resulting from ultraviolet light exposure
Journal of Prosthetic Dentistry, 1995
Five dry pigments and one maxillofacial elastomer were, evaluated for color changes (ΔE) resulting from prolonged exposure to two types of ultraviolet light. The elastomer, pigments, and pigmented elastomers were subjected to each ultraviolet light source for 400, 600, and 1800 hours, and ΔE color shifts were determined. The unpigmented elastomer underwent minimally perceptible color change after 600 hours of exposure to both types of ultraviolet light. Two pigments underwent substantial color change after 400 hours, whereas the remaining three pigments remained color stable after 1800 hours. It was concluded that for the materials tested, early color changes in a prosthesis may be the result of degradation of certain ultraviolet light-susceptible pigments, whereas longer term color shifts may be caused by color changes within the elastomer.
Materials
Facial prostheses are created from special elastomers modified for their specific physical and mechanical properties; however, they also show two common major clinical problems: gradual discolouration of the prosthesis over time in service environment and deterioration of static, dynamic, and physical properties. As a result of external environmental factors, facial prostheses may become discoloured and discolour by changing colour from intrinsic and extrinsic colouring, and this is associated with the intrinsic colour stability of elastomers and colourants. Thus, in this in vitro study, a comparative evaluation of the effect of outdoor weathering on the colour stability of A-103 and A-2000 room-temperature vulcanised silicones used for maxillofacial prosthesis was conducted. To accomplish this study, a total of 80 samples were fabricated, 40 samples of each material were grouped as clear (20) and pigmented (20). These samples were mounted on wooden board and the assembly was placed...
Effects of pigments on dynamic mechanical properties of a maxillofacial prosthetic elastomer
The Journal of prosthetic dentistry, 2014
Pigmentation and coloration play a key role in fabricating a maxillofacial prosthesis. The addition of pigments and dyes to the maxillofacial material may alter the dynamic mechanical behaviors of the prosthesis, possibly influencing the success of the prosthesis. The purpose of this study was to investigate the effects of the type and concentration of intrinsic pigments on the dynamic mechanical properties of a commercially available maxillofacial silicone elastomer over a small range of low frequencies. Ten pigmented mixtures (6 specimens per mixture) were made by using a base silicone elastomer mixed with each intrinsic silicone pigment (Black, Red, Tan, or Yellow) or all the pigments (MixAll) in a designated high or low concentration. The base elastomer without pigment (Unpigment) was prepared as a control. Dynamic mechanical analysis was performed over 5 low frequencies (0.5, 1.0, 1.5, 2.0, and 2.5 Hz) at room temperature. The storage modulus (E'), loss modulus (E″), and lo...
Color stability of facial silicone prosthetic elastomers after artificial weathering
Dental Research …, 2009
Background: External prostheses exhibit an unwanted color change over time. Color deterioration of prosthetic elastomers affects the life expectancy of facial prostheses in a service environment. The effect of different pigmentation and irradiation duration on color stability of four silicone elastomers after artificial weathering was investigated in this study. Methods: The materials used included four different pigmented industrially synthesized RTV (room temperature vulcanizing) silicones. The materials chosen in this study were representative silicone prosthetics that are widely used in the last decade in maxillofacial prostheses. Artificial weathering was performed in a weatherometer of total radiant energy 1.35 W/m 2 (UVA -UVB). The samples were exposed in eight different periods (8, 24, 48, 72, 96, 120, 144, 168 hours). L, a, b readings were obtained before and after weathering from a spectrophotometer to define color changes. Color changes were calculated from the following equation: ∆E = (∆L 2 + ∆a 2 + ∆b 2 )½. The data were subjected to two-way analysis of variance at a significance level of α = 0.05. Also, simple mathematical models were developed for color changes.
Aim: The aim of the study was to evaluate the color stability of maxillofacial silicone elastomer (Cosmesil M511) after exposing them to five different human and environmental aging conditions. Material and methods: Sixty disk-shape maxillofacial silicone Cosmesil M511 (Principality Medical Ltd., South Wales, UK) (Part A: Part B = 10:1) specimens were prepared and equally divided into 5 groups. Dark room (control) (group A),outdoor weathering (group B), acidic perspiration (group C), neutral soap (group D) and disinfectant (group E) along with subgroups in each groups dark brown, medium brown and light brown using the principality skin shade P416, P406 and P418. The conditioning period for Group A, B, C are 3 months; group D and E for 30 hours. Color change (ΔE) was measured at the end of the conditioning period using spectrophotometer. Data was analysed with One-way analysis of variance (ANOVA) and Tukey's Post – Hoc tests. The probability value .05 is considered as significant level. Results: Four of the five treatment conditions induced perceivable color change (ΔE > 3). Specimens stored in outdoor weathering (Group B) condition for 3 months exhibit high (ΔE = 5.68), which was greater (p < 0.05) than that produced by disinfectant (Group E) (ΔE = 5.37). All groups exhibited detectable color change expect for dark room (Group A). Conclusion: There is inherent color stability of the three skin shades (dark brown, medium brown and light brown) which added to the overall color change of the silicone prosthesis. Visual perceptible and clinically unacceptable color change occurred when exposed to various extra oral aging conditions expect dark room condition. It can be said Cosmesil M511 have color instability under extra oral aging conditions.
International Journal of Applied Dental Sciences
Maxillofacial prostheses require enhancement or replacement due to deterioration in their color during their use. The major factors that affect the color of the prostheses are ultraviolet (UV) light exposure, temperature changes, and cleaning and handling by the patient. The aim of the study was to find the effect of extraoral aging conditions on the color stability of high temperature vulcanizing (HTV) and room temperature vulcanizing (RTV) maxillofacial silicone elastomers. Specimens of 25mm x3mm dimensions were fabricated in Techsil S25 HTV silicone and Factor II RTV silicones and processed according to the manufacturer's instructions. Eight groups with eleven specimens each were made. The color stability test was conducted with a Ultraviolet-visible (UV-VIS) spectrometer (Shimadzu) before and after exposure to outdoor weathering and disinfection. The results of the two groups were compared using independent t test. The results of the subgroups were compared with One way ANOVA test followed by Scheffe multiple comparison test. The average color change was found highest in subgroup 4(3.90) and least in subgroup 3(2.3) in HTV samples. The average color change was found highest in subgroup 1(2.70) and least in subgroup 2(1.78) in RTV samples. Color changes caused by HTV samples were significantly greater than that caused by RTV samples. Color changes caused in subgroups 2 and 4 between HTV and RTV samples were significantly greater than in the other groups. There were no significant differences in color change in other subgroups.
Effects of environmental factors on maxillofacial elastomers: Part IV—Optical properties
Journal of Prosthetic Dentistry, 1992
The optical properties of four currently ysed and two recently introduced maxillofacial prosthetic materials were evaluated after the materials were subjected to the following seven environmental variables: natural weathering; normal aging; two types of adhesives; two types of cleaning agents; and cosmetics. Optical density and color changes were evaluated. The currently used silicones Silastic 4-4210 and Silastic 4-4515, Medical Adhesive type A material, and polyurethane all showed more changes in color and optical density than the newly introduced silicone A-102 material. (J PROSTHET DENT 1992;68:820-3.)
Color stability of facial silicone prosthetic polymers after outdoor weathering
The Journal of Prosthetic Dentistry, 1999
Prostheti c elastomers used for the fabrication of facial prostheses have their own physical and mechanical properties, but they do share common clinical problems that can be grouped into 2 major categories: (1) gradual discoloration of prostheses in a service environment and (2) degradation of physical, static, and dynamic mechanical properties. 1-4 The ability to withstand color change when exposed to sunlight over an extended period is one of the most desirable performance characteristics of an ideal facial prosthetic elastomer. 5,6 The discoloration of a facial prosthesis may be caused by color change of intrinsic or extrinsic coloration as a result of external environmental factors and is related to the intrinsic color stability of elastomers and colorants (pigments, flockings), or loss of external coloration on the prosthesis. 7-10 Regardless of the type of elastomer used in the fabrication of a facial prosthesis, its service life is usually 6 months to 2 years, with an average time of 10 to 12 months. 2,3,11 The inherent color stability of nonpigmented elastomer is a contributing variable to the overall color stability of a facial prosthesis experienced in clinical situations. For
Assessment of Exogenous Pigmentation on Clear Elastomeric Modules: An in vitro Study
Orthodontic Journal of Nepal, 2018
Objective: To assess in vitro changes in the shade of clear elastomeric modules from different manufacturers influenced by exogeneous pigmentation contained in everyday dietary substances.Materials & Method: The specimen comprised of clear elastomeric modules (Group A: Libral, Group B: TP Orthodontics) which were immersed in dietary substances: ketchup, coffee, tea, pepsi & methylene blue. Their hue, saturation and intensity were figured after 72 hours by methods of Adobe photoshop CS3 to mirror the module recoloring seriousness.Result: Significant difference was found between two types of modules analyzed in this study. Ketchup and methylene blue demonstrated higher staining potential compared to other staining media. Besides, there was no significant difference in staining contrast between tea and Pepsi.Conclusion: Ketchup and methylene blue are strong staining media, ought to be avoided by the patients opting for aesthetic orthodontic appliances. Elastomeric modules manufactured ...