Dual-Center Cross-Sectional Analysis of Periodontal Stability Around Anterior All-Ceramic Crowns with a Feather-Edge or Chamfer Subgingival Preparation

Subgingival margins are often associated with adverse periodontal reactions, such as recession and gingival inflammation. The purpose of this cross-sectional dual-center study was to evaluate the periodontal health and stability of intrasulcular margins, comparing two prosthetic margin preparations: subgingival chamfer (SC) and subgingival feather-edge (SF) with gingival curettage. Ninetysix patients with 205 crowns (buccal margin 0.5 mm into the gingival sulcus) were included in the study. SF, gingival curettage, and intrasulcular restorative margin were prepared on 109 crowns; SC was prepared on 96. Restorations were in place for a mean of 55.9 months (range: 12 months to 10 years). No significant differences were found regarding probing depth between the two groups (mean buccal: 1.6 mm; mean interproximal: 2.3 mm). Significant increased recession was present around SCs, showing a higher margin-exposure frequency (buccal: 19.8% vs 3.7%; interproximal: 5.2% vs 1.4%). SC showed 8.5 times the risk of margin exposure compared to SF, men 5.5 times compared to women, and smokers 3.7 times compared to nonsmokers. Follow-up time was not a significant factor. SC sites showed a tendency for reduced buccal bleeding on probing compared to SF sites (3.0% vs 12.1%), but no significant difference was seen in a regression model. Plaque presence increased the risk of bleeding (4.1×), and women presented a higher risk of bleeding than men (3×). Subgingival margins can provide adequate periodontal health and stability if restorative procedures are well controlled and if patients are enrolled in an adequate maintenance program. SF with intrasulcular margin favors facial soft tissue stability, as reduced gingival recession was observed. The technique should be carefully applied to promote an adequate periodontal response.