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Color stability of thermochromic pigment in maxillofacial silicone.

Kantola R, Lassila LV, Tolvanen M, Valittu PK - J Adv Prosthodont (2013)

Bottom Line: Half of the surface of each specimen was covered with an aluminium foil.The changes in L(*), a(*) and b(*) values during artificial aging were statistically analyzed by using paired samples t-test and repeated measures ANOVA.P-values <.05 were considered as statistically significant.

View Article: PubMed Central - PubMed

Affiliation: Vaasa Central Hospital, Vaasa, Finland. ; University of Turku, Institute of Dentistry, Department of Biomaterials Science and Turku Biomaterials Centre - TCBC, Turku, Finland.

ABSTRACT

Purpose: Maxillofacial silicone elastomer is usually colored intrinsically with color pigments to match skin colors. The purpose of this study was to investigate the color stability of a maxillofacial silicone elastomer, colored with a thermochromic, color changing pigment.

Materials and methods: Disc-shaped maxillofacial silicone specimens were prepared and divided into 3 groups: a conventionally colored control group, one group additionally colored with 0.2 wt% thermochromic pigment , and one group with 0.6 wt% thermochromic pigment. Half of the surface of each specimen was covered with an aluminium foil. All of the specimens were exposed to UV radiation in 6 hour cycles over 46 days. In between the UV exposures, half of the specimens were stored in darkness, at room temperature, and the other half was stored in an incubator, at a humidity of 97% and a temperature of +37℃. Color measurements were made with a spectrophotometer and registered according to the CIELAB L(*)a(*)b(*) color model system. The changes in L(*), a(*) and b(*) values during artificial aging were statistically analyzed by using paired samples t-test and repeated measures ANOVA. P-values <.05 were considered as statistically significant.

Results: The UV exposure resulted in visually noticeable and statistically significant color changes in the L(*), a(*) and b(*) values in both of the test groups containing thermochromic pigment. Storage in the incubator lead to statistically significant color changes in the a(*) and b(*) values of the specimens containing thermochromic pigment, compared to those stored at room temperature.

Conclusion: The specimens containing thermochromic pigment were very sensitive to UV radiation, and the thermochromic pigment is not suitable, as such, to be used in maxillofacial prostheses.

No MeSH data available.


Related in: MedlinePlus

Comparison of the color value a* (red chroma) of the specimens at day 1 and day 38 of the study.
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Figure 3: Comparison of the color value a* (red chroma) of the specimens at day 1 and day 38 of the study.

Mentions: Statistical analysis revealed that UV irradiation had a significant effect (P<.001) on all color values, L*, a* and b*, of the specimens containing thermochromic pigment, already after one cycle of UV irradiation. In the test group 2/RT the mean a* value of the UV exposed surfaces changed from 7.23 to 11.62 during 37 days. In group 2/37℃, the a* value changed from 7.24 to 13.88. The corresponding a* values in Group 3/RT and Group 3/37℃ were 14.30 and 14.46. Though, the highest a*values in Group 3/RT are seen as soon as on days 3-8 and in group 1/RT, colored only with conventional pigments, mean a* value changed from 3.08 at the baseline to 3.48 at day 46. The a* value is shown in Fig. 3.


Color stability of thermochromic pigment in maxillofacial silicone.

Kantola R, Lassila LV, Tolvanen M, Valittu PK - J Adv Prosthodont (2013)

Comparison of the color value a* (red chroma) of the specimens at day 1 and day 38 of the study.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3675297&req=5

Figure 3: Comparison of the color value a* (red chroma) of the specimens at day 1 and day 38 of the study.
Mentions: Statistical analysis revealed that UV irradiation had a significant effect (P<.001) on all color values, L*, a* and b*, of the specimens containing thermochromic pigment, already after one cycle of UV irradiation. In the test group 2/RT the mean a* value of the UV exposed surfaces changed from 7.23 to 11.62 during 37 days. In group 2/37℃, the a* value changed from 7.24 to 13.88. The corresponding a* values in Group 3/RT and Group 3/37℃ were 14.30 and 14.46. Though, the highest a*values in Group 3/RT are seen as soon as on days 3-8 and in group 1/RT, colored only with conventional pigments, mean a* value changed from 3.08 at the baseline to 3.48 at day 46. The a* value is shown in Fig. 3.

Bottom Line: Half of the surface of each specimen was covered with an aluminium foil.The changes in L(*), a(*) and b(*) values during artificial aging were statistically analyzed by using paired samples t-test and repeated measures ANOVA.P-values <.05 were considered as statistically significant.

View Article: PubMed Central - PubMed

Affiliation: Vaasa Central Hospital, Vaasa, Finland. ; University of Turku, Institute of Dentistry, Department of Biomaterials Science and Turku Biomaterials Centre - TCBC, Turku, Finland.

ABSTRACT

Purpose: Maxillofacial silicone elastomer is usually colored intrinsically with color pigments to match skin colors. The purpose of this study was to investigate the color stability of a maxillofacial silicone elastomer, colored with a thermochromic, color changing pigment.

Materials and methods: Disc-shaped maxillofacial silicone specimens were prepared and divided into 3 groups: a conventionally colored control group, one group additionally colored with 0.2 wt% thermochromic pigment , and one group with 0.6 wt% thermochromic pigment. Half of the surface of each specimen was covered with an aluminium foil. All of the specimens were exposed to UV radiation in 6 hour cycles over 46 days. In between the UV exposures, half of the specimens were stored in darkness, at room temperature, and the other half was stored in an incubator, at a humidity of 97% and a temperature of +37℃. Color measurements were made with a spectrophotometer and registered according to the CIELAB L(*)a(*)b(*) color model system. The changes in L(*), a(*) and b(*) values during artificial aging were statistically analyzed by using paired samples t-test and repeated measures ANOVA. P-values <.05 were considered as statistically significant.

Results: The UV exposure resulted in visually noticeable and statistically significant color changes in the L(*), a(*) and b(*) values in both of the test groups containing thermochromic pigment. Storage in the incubator lead to statistically significant color changes in the a(*) and b(*) values of the specimens containing thermochromic pigment, compared to those stored at room temperature.

Conclusion: The specimens containing thermochromic pigment were very sensitive to UV radiation, and the thermochromic pigment is not suitable, as such, to be used in maxillofacial prostheses.

No MeSH data available.


Related in: MedlinePlus