Color masking measurement for ceramic coating of titanium used for dental implants.

STATEMENT OF PROBLEM: Poor implant placement or thin gingival tissue and progressive bone resorption may lead to the dark metal color showing through the peri-implant soft tissue. Whether the dark color can be adequately masked is unclear.

PURPOSE: The purpose of this in vitro study was to test the color masking effect of porcelain applied on titanium used in fabricating the polished collar of tissue level implants.

MATERIAL AND METHODS: Type 4 commercially pure titanium disks and 5 porcelain dentin shades (A2, A3, B2, C2, and D3) were used. Ten titanium disk specimens per porcelain shade were airborne-particle abraded and ultrasonically cleaned. Porcelain was condensed directly on the specimens, fired, and finished (1200 grit SiC paper). The color (L*a*b* values) of the polished specimens was measured with a reflective spectrophotometer. The specimens were then ground and polished in 0.1 mm increments. Color was measured and ΔE values were calculated at each increment until the thickness at which the ΔE was greater than 3.3 was identified. The data (n=10) were statistically analyzed by ANOVA and the Tukey multiple-comparison test (α=.05).

RESULTS: For ceramic thicknesses greater or equal to 0.5 mm for the A2, A3, B2, and C2 shades, the ΔE was less than 3.3. This value was 0.4 mm for the D3 shade.

CONCLUSIONS: The minimum ceramic thickness required to mask the underlying titanium color is 0.5 mm for all shades except D3, which only needs 0.4 mm. L* decreased with thickness increase. Redness and yellowness increased with thickness increase.