Changes in Peri-Implant Soft Tissue Dimensions Following Soft Tissue Contour Augmentation: A 3-Year Follow-Up of a Multi-Center RCT

Aim: To assess 3-year changes of peri-implant tissues following previous soft tissue (volume) augmentation (STA) with a volume-stable collagen matrix (VCMX) or connective tissue (SCTG) at single-implant restorations. Material and methods: In a non-interventional follow-up observation, peri-implant tissues were evaluated with regard to buccal mucosal thickness (MT) and contour, peri-implant conditions: probing depth (PD), bleeding on probing (BOP), plaque (PI), mucosal margin level/crown height (CH), and clinician-reported esthetics (PE and PES). Patient- and clinician-reported satisfaction was recorded at 3 years (VAS). Mixed-effects models were used to compare the groups. Results: Fifty-six patients (age: 48.0 ± 15.5 years) were followed. MT changes over time did not differ between groups [3.9 ± 1.4 mm to 2.6 ± 1.1 mm for VCMX; 3.8 ± 1.3 mm to 2.9 ± 1.2 mm for SCTG]. The estimated intergroup mean difference (VCMX-SCTG) was 0.2 mm (p = 0.587). Mucosal recession was minimal in both groups [0.2 ± 1.0 mm (VCMX) and 0.2 ± 0.6 mm (SCTG)]. At 3 years, intergroup differences in PE scores amounted to 0.5 at mesial (p = 0.06) and distal sites (p = 0.023) in favor of SCTG. PES scores were high in both groups (VCMX = 10.8; SCTG = 10.9) with no significant differences between the groups (p = 0.580). Patient-reported satisfaction with overall esthetics was high (VAS: SCTG = 9.5; VCMX = 9.6) with no significant intergroup differences. Clinician-reported satisfaction was significantly higher for SCTG (VAS: 8.5) compared with VCMX (VAS: 7.4; p = 0.04). Conclusion: Both VCMX and SCTG maintained stable peri-implant soft tissues with minimal contour changes 3 years after implant loading. Clinician-reported outcome-esthetics overall-favored SCTG; however, patient-reported outcomes did not support this finding.