RESTORATION OF PERIODONTALLY COMPROMISED TEETH WITH TOOTH- OR IMPLANT-SUPPORTED PARTIAL ZIRCONIACERAMIC FIXED PROSTHESES: THREEYEAR RESULTS OF A CLINICAL AUDIT

PURPOSE. To evaluate the clinical outcomes at 3-year follow-up of zirconia-ceramic partial fixed prosthetic restorations of mobile teeth with loss of periodontal attachment. Prostheses were either fitted on natural teeth abutments prepared with a feather-edge finishing line or implant-supported if teeth were not recoverable.

MATERIALS AND METHODS. Subjects with more than 4 mm loss of periodontal clinical attachment level (CAL) and grade 1 to 2 mobility in need, after periodontal therapy, of partial fixed prosthetic restoration supported by either natural teeth or dental implants were included. Teeth were prepared with feather-edge margins. Missing teeth that could not be fitted with a tooth-supported prosthesis were replaced by unsplinted dental implants in association with alveolar crest regenerative procedures when needed. After three to six months of temporization, final impressions were taken, and definitive screw-retained partial zirconia-ceramic fixed prostheses were fitted on either natural teeth or osseointegrated implants. The following outcome measures were evaluated 3 years after definitive prostheses fitting: prosthesis failures, tooth and implant failures, complications and, at teeth only, change in probing depth (PPD), change in bleeding on probing (BoP), and gingival margin recession. A paired t-test was used to evaluate any statistically significant change in PPD between the two time points. The McNemar’s test calculator statistic was used to evaluate any differences between BOP before and after therapy.

RESULTS. Twenty patients were retrospectively assessed. In total, 93 periodontally compromised teeth and 36 intermediate-pontic teeth were restored with ceramic fused to zirconia partial fixed prostheses.
At 3-year follow-up, only one tooth had been lost due to root fracture. Five abutment teeth had been affected by endodontic complications (pulpitis and/or periapical lesions) and eight ceramic chipping.
Three teeth had gingival recession of between 1 and 3 mm. The mean PPD measured around teeth, before cause-related therapy, was 5.2±1.2 mm (95% CI 4.7 to 5.7 mm), which after 3 years had decreased to 2.9±0.8mm (95% CI 2.6 to 3.2 mm), a statistically significant difference (mean difference 2.3±0.8 mm (95% CI 1.9 to 2.7 mm); P-value = 0.000). Forty-two% of the teeth (39 out 93) showed bleeding on probing before cause-related therapy, but this decreased significantly to 12% (11 out of 93) at 3 years after definitive prosthesis delivery (P-value <0.0001).

CONCLUSIONS. Within the limitations of the present clinical audit, partial fixed zirconia-ceramic crowns supported by either natural teeth or implants seem a predictable prosthetic solution for patients with periodontally compromised dentition.