Reconstruction of horizontovertical alveolar defects. Presentation of a novel split-thickness flap design for guided bone regeneration: A case report with 5-year follow-up

Objective: To introduce a novel split-thickness flap design without periosteal and vertical releasing incisions for horizontovertical ridge augmentation. Method and Materials: Three patients with generalized chronic periodontitis presented posterior partial edentulism with class C alveolar defects according to the horizontal, vertical, and combination (HVC) classification. In all three cases, implant placement and simultaneous horizontovertical ridge augmentation utilizing a novel split-thickness flap design was performed. Hard tissue reconstruction was followed by additional soft tissue grafting at membrane removal if optimal peri-implant soft tissue stability could not be ensured. Following abutment connection, fixed implant-retained partial dentures were fabricated. Results: The healing procedure after surgeries was uneventful in all cases, without any serious local or systemic adverse events. After 9 months of healing, complete pocket resolution without gingival recession was observed at neighboring teeth with periodontal attachment loss. A comparison of the mean bone to implant/screw contact at first surgery and at membrane removal demonstrated a mean crestal bone regeneration of 3.08 ± 1.25 mm. At 12 months after prosthetic loading, signs of positive bone remodeling and crestal bone maintenance were shown on intraoral radiographs in all cases. Radiographic results showed maintained alveolar crest contours during 60 months of follow-up in all three cases. Conclusion: The clinical and radiographic observations of the three presented cases demonstrate that the guided bone regeneration technique utilizing titanium membranes in combination with autologous and xenogeneic grafting materials applied with the presented split-thickness flap resulted in predictable three-dimensional reconstruction of hard tissues.