A Review of 30 Years of Alveolar Bone Grafting in the Mixed Dentition Using a Standardized Protocol in Western Australia

Field: Dentistry (Health Sciences)

We read with great interest the recent article entitled “A Review of 30 Years of Alveolar Bone Grafting in the Mixed Dentition Using a Standardized Protocol in Western Australia.”1 We would like to take the opportunity to further expand on our experience with removing the cleft-adjacent cortical bone to increase the success rate of secondary alveolar grafting. Secondary alveolar bone grafting is a well-established technique in the management of patients with cleft lip and palate; any patient with a cleft should be considered for a bone graft. According to the thorough reviews by Witsenburg,2 alveolar grafts were first attempted in the early 1900s using bone and soft tissue from the little finger. A variety of different donor sites have been used since then, with the most common being the iliac crest, calvaria, mandibular symphysis, and tibia. Evidence suggests that oronasal fistula occurrence is greatly reduced when grafts are used. Bone grafts can provide a matrix for tooth eruption and a basis for shaping a closed dental arch, and they may prevent transverse collapse of the anterior maxilla. In addition to establishing maxillary arch continuity with stabilization of the osseous segments, bony support of the nose and lip further leads to restitution and improvement of facial aesthetics.3 However, because of the complicated situations involved in clefting, it is still a big challenge for surgeons to avoid a high possibility of failure, including bad management of segments without orthodontic treatment. Besides the iliac bone graft, many attempts have been made to improve the outcome of secondary alveolar bone grafting, such as activated collagen sponge with reconstructed recombinant human bone morphogenetic protein-2, mesenchymal stem cells, platelet-rich plasma, and so on.4 The key mechanism is to create an osteoinductive microenvironment for improving bone regeneration and remodeling. The skeleton is normally subject to constant remodeling that is mediated by the activity of two different cell types, the bone-forming osteoblasts and the bone-resorbing osteoclasts. Osteoblastogenesis is initiated by differentiation of the mesenchymal stem cells. Osteoclasts are large, multinucleated, terminally differentiated cells from the monocyte-macrophage lineage that are able to resorb bone.5 So the two key cell types involved in balancing the bone remodeling are mostly derived from cancellous bone, and few secondary alveolar bone grafting protocols suggest the removal of the cleft-adjacent cortical bone to increase success by promoting the bone marrow cells and related factors to migrate into the cleft. Therefore, we modified the standard secondary alveolar bone grafting protocol and remove the cleft-adjacent cortical bone before cancellous bone grafting. Figure 1 shows our preliminary results, with improved outcomes compared with traditional techniques. Long-term evaluations will be employed to provide more details about the modified secondary alveolar bone grafting protocol.Fig. 1.: (Left) Incision of the alveolar cleft. (Center) Removal of the cleft-adjacent cortical bone to increase the success rate of secondary alveolar grafting by promoting the bone marrow cells. (Right) Sufficient cancellous bone harvested from the left iliac crest was grafted into the modified cleft space.DISCLOSURE The authors declare there are no sources of support or sponsorship in relation to this communication. The authors have no conflicts of interest to report. Weilong Liu, Ph.D., D.D.S.State Key Laboratory of Oral Diseases and National Clinical Research Center for Oral DiseasesDepartment of Cleft Lip and Palate SurgeryWest China Stomatological HospitalSichuan University Bihe Zhang, Ph.D., D.D.S.State Key Laboratory of Oral Diseases and National Clinical Research Center for Oral Diseases Bing Shi, D.D.S., Ph.D.Cheng-hao Li, Ph.D., D.D.S.State Key Laboratory of Oral Diseases and National Clinical Research Center for Oral DiseasesDepartment of Cleft Lip and Palate SurgeryWest China Stomatological HospitalSichuan UniversityChengdu, People’s Republic of China