Research Corner - Autogenous Connective Tissue Graft or Xenogeneic Collagen Matrix to increase soft tissue thickness around dental implants: what delivers after three years?
We’re pleased to share a precis of a recently published article, thoughtfully prepared by our Honorary Editor, Mr Alex Pollard.
Autogenous Connective Tissue Graft or Xenogeneic Collagen Matrix to increase soft tissue thickness around dental implants: what delivers after three years?
Soft tissue augmentation around implants continues to attract interest, and this multicentre RCT by Surdiacourt and colleagues (J Clin Periodontol, 2025) offers insight into how xenogeneic collagen matrices (XCM) compare with connective tissue grafts (CTG) over three years.
The multi-centre controlled trial randomised 100 patients receiving single implants in the aesthetic zone. In the CTG group, a free gingival graft was harvested from the palate and de-epithelialised extra-orally to a standardised thickness of 1.5 mm. In the test group, a collagen matrix of the same dimensions was used. Both were placed under a split thickness flap over the buccal aspect of the implant site.
At six months, XCM achieved greater initial soft tissue thickening than CTG (1.77 mm vs. 1.26 mm, p = 0.0003). However, this difference did not persist. By three years, CTG had the edge for soft tissue stability, with a final thickness of 1.43 mm compared to 1.11 mm for XCM (p = 0.0459).
The most clinically relevant outcome may be crestal bone loss. Radiographs showed that the XCM group lost significantly more bone over three years (mean loss 1.13 mm vs. 0.71 mm for CTG, p = 0.0327). No differences were seen in midfacial recession or Pink Aesthetic Scores. Both groups had comparable long-term patient satisfaction, although the CTG group experienced more early post-operative pain and a greater impact on daily life in the short term.
It is worth noting the study was industry funded, and while methodology was sound, this should be considered when evaluating the results. However, there was evidence of standardisation of surgical technique and blinding of the examiners, which reduces the risk of bias.
What is my takeaway? CTG remains the gold standard for soft tissue augmentation around implants, offering greater long-term volume stability and better preservation of crestal bone. While collagen matrices may appeal due to reduced surgical complexity and morbidity whilst maintaining acceptable aesthetic outcomes, the findings here suggest that this convenience comes with some biological cost compared to the CTG. However, case selection is key and in many cases a XCM will be perfectly adequate for the job.