The Difference in the Surgical Outcome of Unilateral Cleft Lip and Palate Between Patients With and Without Pre-Alveolar Bone Graft Orthodontic Treatment

Overall goals of study:

The goals of this study are to determine whether pre-operative orthodontic treatment will affect secondary alveolar bone grafting outcome

Importance of alveolar bone grafting Alveolar bone cleft is present in the majority of patients with cleft lip and palate. This bone cleft destabilizes the maxillary arch and predisposes it to medial collapse. Teeth will not erupt in this region of alveolar bone defect. Permanent stabilization of the maxillary segments into a functional dental arch form is achieved by reconstruction of alveolar with bone grafts. The goals of alveolar bone grafting are to maintain normal occlusion and to provide a matrix for the continued eruption of permanent teeth in this region. Moreover, future maxillary expansion cannot be done unless repair of the alveolar cleft is coordinated with the desired orthodontic movement.

Timing of alveolar bone grafting Maxillary growth and dental age are the predominant considerations in determining the timing of alveolar reconstruction. Maxillary growth is completed near the age of eight years old, whereas the maxillary canine does not erupt before the age of ten.Therefore, to minimize growth disturbance to the maxilla, reconstruction should be performed after the growth is completed.It has been widely agreed that the timing of alveolar grafting should be around the stage of mixed dentition . The bone grafting should be completed at approximately nine years of age when the bulk of the alveolar bone growth is completed and the incisors are erupted, while the lateral incisors and canines are starting to erupt into alveolar cleft region

Diagnosis Radiographic studies, including panoramic radiographs, selected periapical films, Cephalographic films and recently CT scan are integral parts for diagnosis and evaluation. They provide important assessments of the pre-operative dentition in the vicinity of the cleft, the dimensions and structures of cleft itself as well as postoperative condition of the bone bridge after alveolar bone grafting.The CT scan offers more detailed pre-operative and post-operative bone structures with less distortion. Additionally, CT scan also provide: 1. Detailed information about the depth and volume of bone deposited in the cleft, 2. More consistent in showing bone trabeculation, 3. Detailed position of erupting teeth relative to the bone graft, 4. More detailed bone and teeth anatomy for clinical orthodontics decisions. In addition, the CT scan could offer 3D lineal measurements and volumetric analysis . Arai et al. developed a novel cone-bean CT (CBCT) or Ortho CT which has important characteristics such as lowered radiation dose and the ability to produce higher resolution compared to conventional spiral CT. Several reports have indicated that it is clinical useful for the 3D imaging diagnosis in the maxillofacial region.