Tunnel Technique Vs Open Augmentation with PTFE Membrane for Horizontal Ridge Augmentation

OBJECTIVE: This retrospective case series evaluated the outcomes of the tunnel technique without membrane placement compared to an open technique with PTFE membrane placement for horizontal ridge augmentation in the mandible and maxilla.

PATIENTS AND METHODS: A retrospective chart review of implant patients treated with the two techniques between 04/2013 and 11/2014 was done.  Thirty (n=30)(57%) ridge augmentations were performed via open technique using a PTFE membrane secured with at least 3 titanium screws, while twenty-three (n=23)(43%) augmentations were completed using the tunnel technique without the use of a membrane as described by Block.  Grafting material for both techniques consisted of a 50:50 mix of mineralized freeze-dried bone allograft and bovine-derived hydroxyapatite. All procedures were completed by senior level residents. Patients were followed until implants were placed. The following factors were compared for both techniques: number of visits needed prior to implant placement, dehiscence of the graft or membrane requiring removal of membrane or graft material prior to graft maturation, infection and/or need for antibiotics after the initial peri-operative antibiotic course, cost of materials for the initial graft procedure, and percentage of augmented sites that were suitable to receive implants.

RESULTS: Within six months of bone grafting, 91% of patients with tunnel technique grafts received dental implants while 86% of patients with the open technique received dental implants (p < 0.05).  39% of membranes got exposed, but only 7% needed removal during the healing phase. Antibiotics were prescribed three times more frequently with the open technique (p<0.05). 65% of patients with open techniques had 5 or more post-operative visits related to complications, while only 11% of patients with tunnel technique had to be seen more than 3 times post-operatively (p<0.05).  The average increased cost of materials for the open technique was $336 more than the tunnel technique.

CONCLUSIONS: The results of this study suggest that for alveolar ridge defects that require horizontal augmentation prior to implant placement, the tunnel technique offers several advantages.  The patients required less post-operative visits, had lower infection rates and less need for systemic antibiotics during the healing phase, fewer required debridement or membrane removal during the healing phase, and overall cost was less.