Spectrophotometric analysis of fluorescent zirconia abutments compared to "conventional" zirconia abutments: A within subject controlled clinical trial.

BACKGROUND: Zirconia abutments are frequently used for implant-supported single crowns. Even though demonstrating esthetic benefits compared to metal abutments, zirconia abutments lead to an increased brightness of the peri-implant mucosa compared to natural teeth and are not ideal from an esthetic point of view. PURPOSE: To test whether or not a fluorescent hybrid zirconia abutment offers superior esthetics compared to a non-fluorescent one-piece zirconia abutment based on spectrophotometric analysis. MATERIALS AND METHODS: In 24 patients with 24 single-tooth implants, 2 types of reconstructions were fabricated: a directly veneered one-piece zirconia abutment/crown (control) and a directly veneered fluorescent hybrid zirconia abutment/crown (test). Spectrophotometric assessment was performed: prior to abutment insertion (WA), at abutment try-in (A), at the try-in of the final crowns (C). Color differences (DeltaE) were assessed compared to the gingiva of natural teeth (T) and between the reconstructions. RESULTS: At abutment try-in, DeltaE values were 8.49 +/- 3.59 for A(Control) and 8.27 +/- 4.03 for A(Test) compared to T. At crown insertion, DeltaE values were 7.61 +/- 4.03 for C(Control) and 8.32 +/- 3.57 for C(Test) compared to T. The difference in DeltaE values between A(Control) and A(Test) was 0.23 +/- 2.54 (P = .37), whereas the difference in DeltaE values between C(Control) and C(Test) was -0.66 +/-3.45 (P = .48). For all cases with a mucosal thickness </=2 mm, the comparison between C(Control) and C(Test) was significant in favor of the control group (P = .03). CONCLUSIONS: Both types of reconstructions were similar in terms of esthetics. Incases with a mucosal thickness of <2 mm, the soft tissue discoloration compared to the natural gingiva was more pronounced for the fluorescent hybrid zirconia reconstructions.