title: Bone reactions around dental implants subjected to progressive static load: an experimental study in dogs.
abstract: OBJECTIVE
  To evaluate histologically and histomorphometrically, the peri-implant bone reaction around implants subjected to controlled progressive orthodontic loading.
  
  
  METHODS
  In three beagle dogs, bilateral edentulous flat alveolar ridges were created in the maxillary area posterior to the canines. After 8 weeks of healing, 24 implants (Biomet 3i) were inserted in the edentulous sites. Two experimental groups were created. Progressive loading group: Twelve implants were left to heal for 8 weeks uncovered, and abutments were adapted and connected by pairs with Ni-Ti orthodontic springs. A gradual static force of 100, 200 and 300 g was applied for a 3-week period each. Thus, a total progressive loading period of 9 weeks was exercised. Unloaded control group: Twelve implants were left to heal undisturbed. At the end of the experimental period, all implants of both groups were removed with the surrounding bone. Histologic and histomorphometric analyses were performed, and the following parameters were measured: bone-to-implant contact, bone density 1 and 2 mm distant to the implant threads and crestal bone resorption. Median regression models are used for statistical analysis.
  
  
  RESULTS
  Implants of the progressive loading group exhibited significantly higher percentage of bone-to-implant contact compared to the unloaded control implants (P = 0.018). Bone density 1 and 2 mm distant to the threads was found to be the same between the two groups (P = 0.734 and P = 0.961, respectively). Crestal bone resorption did not differ between loaded and unloaded implants (P = 0.813).
  
  
  CONCLUSIONS
  The application of progressive loading by controlled orthodontic force on osseointegrated implants provoked significant increase in the percentage of bone-to-implant contact of the low-density bone of the dog maxilla.
authors.affiliation: Department of Oral and Maxillofacial Surgery, Dental School, University of Athens, Athens, Greece.
authors.forename: Leonidas
authors.initials: L
authors.lastname: Podaropoulos
authors.affiliation: Department of Surgery, Implantology and Radiology, Dental School, Aristotle University of Thessaloniki, Thessaloniki, Greece.
authors.forename: Alexander A
authors.initials: AA
authors.lastname: Veis
authors.affiliation: Biomaterial Clinical Research Association, Private Practice, Pescara, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Trisi
authors.affiliation: Companion Animal Clinic, School of Veterinary Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece.
authors.forename: Serafim
authors.initials: S
authors.lastname: Papadimitriou
authors.affiliation: Department of Oral and Maxillofacial Surgery, Dental School, University of Athens, Athens, Greece.
authors.forename: Constantinos
authors.initials: C
authors.lastname: Alexandridis
authors.affiliation: Department of Oral and Maxillofacial Surgery, Dental School, University of Athens, Athens, Greece.
authors.forename: Demos
authors.initials: D
authors.lastname: Kalyvas
mesh_terms: D000818:Animals; D000069343:Bone-Implant Interface / Q000473:pathology*; D015921:Dental Implants; D003799:Dental Stress Analysis; D004285:Dogs; D008437:Maxilla; D016348:Osseointegration
chemical_list: D015921:Dental Implants
keywords: bone density; bone remodeling; bone resorption; bone-implant contact; osseointegration; progressive load; static load; titanium implants