title: Assessment of bone resorption after secondary alveolar bone grafting using three-dimensional computed tomography: a three-year study.
abstract: OBJECTIVE
  Secondary bone grafting plays an important role in the dental rehabilitation of patients with clefts of the lip, alveolus, and palate. A major complication of this surgical technique is resorption of the grafted bone transplant. Conventional two-dimensional radiographs are often inconclusive and do not demonstrate the true deficit. The main objective of this study was to evaluate the amount and exact location of bone loss on the basis of three-dimensional models over a period of 3 years.
  
  
  METHODS
  Twenty-four patients with unilateral cleft palate were included in this prospective study. Axial computed tomography scans of all patients were taken immediately preoperatively, and 1, 2, and 3 years postoperatively. Volumetric analysis was performed on three-dimensional models of the cleft defects and the bone bridges using three-dimensional computed tomography.
  
  
  METHODS
  All patients were treated by secondary alveolar bone grafting prior to eruption of the permanent canine.
  
  
  RESULTS
  Extensive bone resorption was found in the bucco-palatal dimension of the alveolar portion of the transplant. The success rate of secondary bone grafting was high in cases of rapid orthodontic gap closures. The mean bone loss in the first year after surgery was 49.5%. The transplants remained almost constant in the following 2 years.
  
  
  CONCLUSIONS
  Radiographic scales based on orthopantomography only evaluate the vertical dimension of the transplants. This study, however, showed that bone resorption in the transversal dimension is clearly underestimated with conventional two-dimensional radiographs.
authors.affiliation: Department of Oral and Maxillofacial Surgery, Medical University of Graz, Graz, Austria. matthias.feichtinger@meduni-graz.at
authors.forename: Matthias
authors.initials: M
authors.lastname: Feichtinger
authors.forename: Rudolf
authors.initials: R
authors.lastname: Mossböck
authors.forename: Hans
authors.initials: H
authors.lastname: Kärcher
mesh_terms: D000293:Adolescent; D000539:Alveolar Process / Q000000981:diagnostic imaging; D000543:Alveoloplasty; D001862:Bone Resorption / Q000000981:diagnostic imaging*; D016025:Bone Transplantation / Q000000981:diagnostic imaging*; D002648:Child; D002971:Cleft Lip / Q000000981:diagnostic imaging / Q000601:surgery; D002972:Cleft Palate / Q000000981:diagnostic imaging / Q000601:surgery; D003481:Cuspid / Q000502:physiology; D005260:Female; D005500:Follow-Up Studies; D006085:Graft Survival; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D008437:Maxilla / Q000000981:diagnostic imaging / Q000601:surgery*; D010159:Palate / Q000000981:diagnostic imaging; D011183:Postoperative Complications / Q000000981:diagnostic imaging*; D011446:Prospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014078:Tooth Eruption / Q000502:physiology; D016896:Treatment Outcome