An alternative method of augmenting a narrow ridge is by ridge splitting instead of onlay grafting. This technique can be applied in selected cases. It requires that the alveolar ridge has two cortical plates separated by a layer of cancellous bone in a preoperative CBCT image. This situation is normally confined to alveolar ridges featuring an orofacial thickness of more than 4mm.
Ridge splitting can be performed simultaneously with implant placement. This is the only way to obtain primary stability in this scenario is by engaging the bone at the apical region of the implant. In selected cases, it may be possible to stabilize the mobilized buccal plate with bone screws if required.
It is advisable to perform the splitting with minimal flap reflection to expose only the crestal region of the ridge. A somewhat higher level of surgical skill and experience is needed for flapless ridge splitting compared to conventional bone grafting .
The main indication for ridge splitting is to expand a horizontally reduced ridge in the maxilla and take advantage of elastic and cancellous quality of this bone and its peripheral type of blood perfusion.
Splitting a narrow mandibular ridge is possible but technically more difficult due to brittle, thicker, and more cortical nature of this bone .
A flapless approach in the maxilla offers the benefits that even small bone fragments remain attached to periosteum and are contained by the intact soft-tissue envelope. On balance, ridge expansion via splitting is effective but does have its limitations.
Onlay bone grafting, with addition to particulated grafts and a membrane for protection, is the more versatile and widely used approach
Regards :Dr.Prof.Rajat Sachdeva