New Incision and Flap Designs in Autogenous Bone Ring Grafting with Simultaneous Implant Placement and an Evaluation of the Effect of First-Stage Wound Dehiscence in Dogs

Purpose The aim of this study was to explore the effect of preventing first-stage wound dehiscence with new types of incision and flap design and to evaluate the effect of wound dehiscence on the bone resorption of the autogenous bone ring graft. Materials and methods In six beagle dogs, the second and fourth premolars on the bilateral mandible were extracted. After 3 months, on the left extraction sites, conventional alveolar crest incisions were made and the full-thickness flaps were elevated. However, on the right sites, the incisions were made at the mucogingival junction, the split-thickness flaps were elevated toward the lingual side, and the periosteum was elevated toward the buccal side. Then, Straumann implants (. 3.3, length 8 mm) were placed with simultaneous autogenous bone ring grafting. Next, the wounds on the left side were closed with periosteal releasing on buccal flaps conventionally, but the semi-thickness flaps on the right side were sutured with the elevated periosteum. After 3 months, the animals were euthanized, and the harvested samples were analyzed using microcomputed tomography and histology. Results The incidence rate of wound dehiscence in the new incision group was 16.7%, which was significantly lower than that in the conventional incision group (75%). There was hardly any vertical bone loss of the bone ring in the samples without wound dehiscence, but in wound dehiscence samples, severe bone loss, 2.47 ± 0.17 mm, was found on the buccal side of the bone ring, which was significantly higher than that on the lingual, mesial, and distal sides, 1.37 ± 0.14 mm, 1.00 ± 0.15 mm, and 1.03 ± 0.05 mm, respectively. Conclusion The use of a mucogingival junction incision and split-thickness flap design can effectively prevent first-stage wound dehiscence in autogenous bone ring grafting, which plays a key role in bone resorption of the graft.