Acellular dermal matrix for root coverage procedures: 9-year assessment of treated isolated gingival recessions and their adjacent untreated sites

Background: The long-term outcomes of acellular dermal matrix (ADM) for the treatment of isolated gingival recessions has not yet been evaluated. Thus, the aim of this study was to observe the root coverage outcomes of coronally advanced flap with ADM over time, and compare them with their adjacent untreated sites. Methods: Twelve patients (from 20) were available at the 9-year recall. Clinical parameters (recession depth, mean root coverage [mRC], keratinized tissue width [KTW], and gingival thickness) were evaluated and compared with the 1-year results, and the ADM-adjacent untreated sites (on mesial and distal) via mixed-modeling regression analyses. Results: From 1 to 9 years, the ADM-treated isolated recessions showed a relapse from 77% to 62% mRC (P <0.05). A similar pattern toward apical shift of the gingival margin was noticed for the ADM-adjacent untreated sites without baseline recession. However, ADM-adjacent untreated sites which had presented with recession at baseline but were not treated showed a significantly more apical shift of the gingival margin (almost two-fold). A significant increase in KTW was noted for all sites. Baseline KTW ≥2 mm was a significant predictor for the stability of the gingival margin at the ADM-treated, and the ADM-adjacent sites with baseline recession. Conclusions: ADM-treated sites displayed recession relapse from 1 to 9 years. The untreated adjacent sites with a recession at baseline, showed a higher apical displacement of the gingival margin compared with the ADM-treated sites, and ADM-adjacent sites without a recession at baseline.