Restoration of the mandibular osseous ridge by bone split and expansion : a case study

Aim of the study

To demonstrate that osteogenesis after bone split and expansion can, in some cases, be a valuable alternative to increasing the height of the crest by guided bone regeneration (GBR).

Materials and methods

A 30 year old patient presented with an atrophic alveolar ridge after extraction of the mandibular anterior teeth following a road traffic accident. A fragment of mandibular bone was separated from the mandible by vertical and horizontal osteotomy section. The fragment was progressively displaced with the aid of an intra-osseous screw separator. After 5 days healing, the screw was turned two complete turns per day, providing 1 mm displacement.

Results

Healing was uneventful, without pain or discomfort to the patient. The device was removed after 30 days and implants could be placed after 60 days. The expansion of the newly-formed callus each day for 10 days allowed a clinical expansion of the ridge by 7 mm. Histological examination of the newly-formed bone (removed during insertion of the implants) showed bundle bone formation with intersecting fibres.

Conclusion

This technique permits the vertical displacement of small bone fragments in relatively short periods of time. The predictability of the technique is better than that with GBR. The intra-osseous separator is well tolerated by the patient. The delay before bringing the implants into function in these cases has yet to be determined in humans.

Commentary

The use of a new intra-osseous separating device (ACE Surgical Supply^®) seems to us to be a promising development for use in certain cases, to take advantage of the concept of progressive separation which is regularly applied to surgical orthopaedics and maxillofacial surgery.