Soft-tissue augmentation techniques for enhancing peri-implant volume: A systematic review

Abstract: Background: This systematic review aimed to critically evaluate the effectiveness of soft-tissue augmentation (STA) techniques for enhancing peri-implant soft-tissue thickness and volume around dental implants with compromised soft tissue. Materials and Methods: A comprehensive electronic and manual search was performed in MEDLINE via PubMed and EMBASE via Ovid, covering studies published in English up to December 2024. Human studies investigating STA techniques for peri-implant soft-tissue volume augmentation were included. The Joanna Briggs Institute critical appraisal tools, selected according to study design, were used to assess the risk of bias in randomized controlled trials (RCTs), prospective clinical studies (PCS), and case series (CS). Due to methodological heterogeneity, data were synthesized qualitatively rather than through meta-analysis. Results: Thirty-one studies (20 RCTs, 5 PCS, and 6 CS) were included. Reported soft-tissue thickness gain ranged from 0.08 to 3.59 mm and volume gain from 0.16 to 186.38 mm 3 , where gains ≥2 mm were generally considered clinically relevant for peri-implant tissue improvement and mucosal stability. Despite a predominantly high risk of bias, the subepithelial connective tissue graft (SCTG) combined with a split-thickness flap provided the most consistent outcomes. Variations in surgical protocols, follow-up durations, and measurement methods precluded quantitative meta-analysis. Conclusion: Within the limitations of heterogeneity and potential bias, STA techniques, particularly SCTGs, show promising potential for enhancing peri-implant soft-tissue thickness and volume. However, given the moderate-to-high risk of bias and the lack of a pooled analysis, these results should be interpreted with caution. Further well-designed RCTs with standardized methodologies, consistent outcome measures, and long-term follow-up are essential to validate these findings and optimize clinical protocols.