title: Histological evaluation of osseous defects combined with orthodontic tooth movement.
abstract: BACKGROUND
  The aim of this study was to histologically evaluate the effectiveness of different times of initiating orthodontic tooth movement on enhancement of bone formation in surgical bony defects.
  
  
  METHODS
  In 18 male guinea pigs, 3-4 months of age, a bony defect was created in the alveolar process midway between the central incisor and mandibular 1st molar. These bony defects were implanted with bioactive glass particles and collagen membrane. According to the application of the orthodontic tooth movement, the animals were divided into three groups, each comprised of six guinea pigs. In Group I, the orthodontic tooth movement was initiated immediately after the surgical procedure. In Group II, the orthodontic tooth movement was applied 2 weeks after the surgical procedure, while in Group III no orthodontic tooth movement was applied. Section blocks for histology were made at 1, 3 and 6 weeks after the surgical procedure.
  
  
  RESULTS
  All experimental sites showed active bone formation with plump osteoblast and osteoid matrix deposition in the treated area. In Groups I and II a dense fibrous tissue formation and highly cellular coarse bone were seen at six weeks. The histomorphometric analysis showed that Group I revealed the greatest number of newly formed trabeculae: 2.4, 6.4 and 8.6 at 1, 3 and 6 weeks, respectively. In addition, Group I defects revealed a greater total surface area of newly formed bone than Groups I and III: 2.96 mm2 at the end of the study period.
  
  
  CONCLUSIONS
  The combined orthodontic/regenerative therapy seemed to enhance the process of bone formation. Bone formation was histologically observed in all test groups. Defects treated with immediate application of orthodontic tooth movement showed a statistically significant increase in trabecular count and total surface area of newly formed bone than the other experimental groups.
authors.affiliation: Department of Oral Medicine, Periodontology, Oral Diagnosis and Radiology, Faculty of Dental Medicine-Girls' Branch, Al Azhar University, Cairo, Egypt. mai_shafik@yahoo.com
authors.forename: Mai Shafik
authors.initials: MS
authors.lastname: Attia
authors.forename: Eatemad A
authors.initials: EA
authors.lastname: Shoreibah
authors.forename: Samir A
authors.initials: SA
authors.lastname: Ibrahim
authors.forename: Hamdy A
authors.initials: HA
authors.lastname: Nassar
mesh_terms: D016301:Alveolar Bone Loss / Q000601:surgery*; D000818:Animals; D001672:Biocompatible Materials / Q000627:therapeutic use; D001853:Bone Marrow / Q000473:pathology; D001857:Bone Matrix / Q000473:pathology; D001861:Bone Regeneration / Q000502:physiology; D018786:Bone Substitutes / Q000627:therapeutic use; D002452:Cell Count; D002516:Ceramics; D003094:Collagen; D003238:Connective Tissue / Q000473:pathology; D006097:Granulation Tissue / Q000473:pathology; D006168:Guinea Pigs; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008297:Male; D008334:Mandible / Q000473:pathology / Q000601:surgery; D008336:Mandibular Diseases / Q000601:surgery; D008567:Membranes, Artificial; D010006:Osteoblasts / Q000473:pathology; D010010:Osteoclasts / Q000473:pathology; D010012:Osteogenesis / Q000502:physiology*; D013997:Time Factors; D014087:Tooth Movement Techniques / Q000379:methods*
chemical_list: D001672:Biocompatible Materials; C022107:Bioglass; D018786:Bone Substitutes; D008567:Membranes, Artificial; D003094:Collagen