The effect of soft tissue augmentation on clinical outcomes in implants placed in healed mandibular sites with thin (< 1.5 mm) buccal bone

Background & Aim: The long-term stability of osseointegrated dental implants is highly dependent on the anatomical condition of the hard and soft tissue, especially on the buccal side. The literature has so far suggested minimal buccal bone thickness of 2 mm for long-term implant stability. The aim of this prospective study was to evaluate the clinical outcomes of implants placed in healed implant sites in the lower jaw with buccal bone thinner than 1.5 mm after implant placement and simultaneously augmented merely with soft tissue graft. Methods: Twenty-three soft-tissue level implants (TRI Octa, Tri, Swiss) were placed in healed mandibular implant sites following the principles of the mucogingival approach. All implant sites presented buccal bone width < 1.5 mm after implant placement. Hence the soft tissue at the buccal implant side was augmented with de-epithelized gingival graft from the palate in a bilaminar fashion, without any bone augmentation procedures. The evaluated clinical outcomes were bleeding and plaque scores, probing depth, marginal tissue recession and interproximal bone levels at one and two years post implant loading with screw-retained zirconia restorations. Results: All implants were successfully osseointegrated. All implant sites presented low bleeding and plaque scores, physiological probing depths, absence of inter-proximal bone loss and no marginal tissue recession at the two short-term timepoints. Conclusions: Implants may be clinically stable in an environment with buccal bone thinner than 1.5 mm provided that soft tissue is thick and healthy. The bilaminar soft tissue augmentation with mucogingival approach may a viable treatment option for providing implant stability in sites with thin buccal bone.