[Preliminary clinical evaluation of the esthetic effect of deep discolored anterior teeth restored with zirconia veneers].

OBJECTIVE: To observe the esthetic effect of deep discolored anterior teeth restored by zirconia veneers.

METHODS: Small defected deep discolored anterior teeth with complete root canal therapy were restored by zirconia veneers (n=15). The same name teeth on the other side of the same dental arch were chosen as control teeth. The color difference values ΔE of the neck 1/3, the middle 1/3 and the incisor 1/3 between the deep discolored tooth and the normal control tooth before and after therapy were measured to evaluate the esthetic effect of zirconia veneer restoration. At the same time, the marginal fit of zirconia veneers was checked by the standard of United States Public Health Service (USPHS). The integrity of the veneers was also examined.

RESULTS: On the labial side, fibers color difference values ΔE of the neck 1/3, the middle 1/3 and the incisor 1/3 between deep discolored teeth and normal control teeth were measured by the electronic colorimeter, which were 24.92±3.00,26.64±4.00 and 21.94±3.31 respectively. All the values were above 4.0, which were considered unacceptable in clinic. After restoration by zirconia veneers, the color difference values ΔE of the middle 1/3 and the incisor 1/3 between the restored and control teeth were 1.82±0.17 and 1.84±0.21. Both values were less than 2.0, which indicated both good color matching. The color difference value ΔE of the neck 1/3 was 3.92±0.48, which was less than 4.0 and could be accepted in clinic. The statistical analysis of the colors of the teeth before and after restoration compared with the control teeth was done by Paired t test. The t values in the neck 1/3, the middle 1/3 and the incisor 1/3 were 30.37, 21.56, 23.37 respectively. In the three group, all the P<0.001. There were obvious statistical differences. According to the standard of USPHS, the marginal fit of all the restored teeth was perfect (grade A). No zirconia veneers were broken or detached in the period of observation.

CONCLUSION: Zirconia veneers can be a good method to restore deep discolored anterior teeth. However, it should be used cautiously when the patient's esthetic expectation was too high.