Colour Change of Zirconia and Lithium Disilicate Following Surface Treatment With Silver Diamine Fluoride

Objectives: This laboratory study investigated the effect of silver diamine fluoride (SDF) on the colour of zirconia and lithium disilicate.
Methods: Zirconia (3Y-TZP and 5Y-TZP) and lithium disilicate (LS) specimens were prepared and subject to surface treatment using deionized water (Group A, control), 38% silver diamine fluoride (SDF) (Group B), 25% silver nitrate solution (Group C), 5% sodium fluoride solution (Group D), or 38% SDF then rinsed with deionized water (Group E). All specimens were blot-dried after treatment and stored at 37 degrees Celsius and 90% relative humidity. One other group of specimens was treated with 38% SDF then rinsed with deionized water and stored in artificial saliva (Group F). Colour measurement of the specimens was performed using a spectrophotometer at baseline and on days 1, 3 and 7 after surface treatment to obtain the L*, a* and b* values. Colour change for days 1, 3 and 7 was computed for each specimen by comparing it to the colour at baseline.
Results: All specimens showed colour change after surface treatment. The range of colour change of 3Y-TZP, 5Y-TZP and LS was 0.17 to 20.18, 0.38 to 16.51 and 0.12 to 11.32, respectively. Significant differences in the degree of colour change were obtained in Groups B and C over time (p < 0.01), and between Groups B and C and the other groups (p < 0.005) for both zirconia and LS. These specimens became darker and more reddish and varied in yellowness.
Results: All specimens showed colour change after surface treatment. The range of colour change of 3Y-TZP, 5Y-TZP and LS was 0.17 to 20.18, 0.38 to 16.51 and 0.12 to 11.32, respectively. Significant differences in the degree of colour change were obtained in Groups B and C over time (p < 0.01), and between Groups B and C and the other groups (p < 0.005) for both zirconia and LS. These specimens became darker and more reddish and varied in yellowness.
Conclusions: There is a significant colour change of zirconia and lithium disilicate after surface treatment with SDF accompanied by blot-drying.