Rapid Horizontal Osseo-Distraction (RHOD) performed with ultra-sonic surgery

Objectives: To facilitate horizontal split-crest in corticalized atrophic mandibles with ultra-sonic bone surgery device (Ultrasonic Bone Surgery UBS®). Methods: 5 mandibular hemi-arcades scheduled for implant-supported restoration were included. Inclusion criteria were: 2-3mm residual alveolar ridge, available bone height above the mandibular canal accommodating at least 10 mm long implants. A split-crest procedure with UBS® vibrating tips (20-32 khz range) was used. The surgery consisted into a longitudinal crestal incision, 2 vertical releasing incisions and partial thickness longitudinal discharge notch performed apically on the buccal plate. The latter incision was performed 2 mm above the foreseen implant apical extremity. A RHOD device was used to achieve a ridge expansion between the buccal and lingual bone flaps. By successive activating opening-closing movements of the RHOD device and by performing the basal longitudinal notch, resilience was achieved to the hard bone in order to achieve buccal bone flap mobilization. 15 implants were placed (3.75mm Ø and 10-13mm length). In the furrow, no filling material was placed. BioOss© was placed only on the coronal implant side and buccally to reshape the alveolar plate. After 6 months of submerged healing, implants were loaded.

Results: All hemi-arcades had corticalized dense bone. They were successfully widened without fracturing the hard buccal and lingual plates due to the basal longitudinal partial thickness cut. With UBS, this could be done straightforwardly, without risk of local soft tissue injiuries. Flap realising could be restricted to the minimum to place the tip deep into alveolar bone. All implants have been loaded for at 24-36 months.

Conclusion: RHOD with UBS® was performed in a much easier way than with rotative instruments. Especially, the longitudinal basal partial thickness cut allowed a predictive outcome of the procedure. It was not necessary to extend the access flap to perform the basal cut.