title: Healing of implants installed in over- or under-prepared sites--an experimental study in dogs.
abstract: OBJECTIVE
  To study bone healing at implants installed with different insertion torques.
  
  
  METHODS
  In six Labrador dogs, all mandibular premolars and first molars were extracted. After 4 months of healing, flaps were elevated, and two implant sites were prepared at each side of the mandible. In the right side of the mandible, the distal sites were prepared conventionally, while the mesial sites were over-prepared by 0.2 mm. As a consequence, a final insertion torque of ~30 Ncm at the distal and a minimal insertion torque close to 0 Ncm at the mesial sites were obtained. In the left sides of the mandible, however, the recipient sites were underprepared by 0.3 mm resulting in an insertion torque of ≥ 70 Ncm at both implants. Cover screws were applied, and flaps sutured to fully submerge the experimental sites. After 4 months, the animals were sacrificed and ground sections obtained for histological evaluation.
  
  
  RESULTS
  The mineralized bone-to-implant contact was in the range of 55.2-62.1%, displaying the highest value at implants with ~30 Ncm insertion torque and the lowest value at the implant sites with close to 0 Ncm insertion torque. No statistically significant differences were revealed. Bone density was in the range of 43.4-54.9%, yielding the highest value at implants with ≥ 70 Ncm insertion torque and the lowest at the implant sites with close to 0 Ncm insertion torque. The difference between the sites of ~30 Ncm and the corresponding ≥ 70 Ncm insertion torque reached statistical significance.
  
  
  CONCLUSIONS
  Similar amounts of osseointegration were obtained irrespective of the insertion torque applied. Moreover, implants installed in sites with close to 0 Ncm insertion torque may properly osseointegrate as well.
authors.affiliation: Faculty of Dentistry, University of Medical Science, La Habana, Cuba.
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Rea
authors.affiliation: The University of Hong Kong, Prince Philip Dental Hospital, Hong Kong, China.|University of Zurich, Zurich, Switzerland.
authors.forename: Niklaus P
authors.initials: NP
authors.lastname: Lang
authors.affiliation: University of Padoa, Padova, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Ricci
authors.affiliation: Private Practice, Modena, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Mintrone
authors.affiliation: Faculty of Dentistry, University of Medical Science, La Habana, Cuba.
authors.forename: Gladys
authors.initials: G
authors.lastname: González González
authors.affiliation: Faculty of Dentistry, University of Medical Science, La Habana, Cuba.|The University of Hong Kong, Prince Philip Dental Hospital, Hong Kong, China.|University of Padoa, Padova, Italy.|Faculdade de Odontologia de Araçatuba, UNESP, Universidade Estadual Paulista, São Paulo, Brasil.|ARDEC, Ariminum Odontologica, Rimini, Italy.
authors.forename: Daniele
authors.initials: D
authors.lastname: Botticelli
mesh_terms: D000818:Animals; D001641:Bicuspid; D003758:Dental Implantation, Endosseous / Q000379:methods*; D015921:Dental Implants; D004285:Dogs; D008334:Mandible / Q000601:surgery*; D008963:Molar; D016348:Osseointegration; D013524:Surgical Flaps; D014081:Tooth Extraction; D019415:Torque; D014945:Wound Healing
chemical_list: D015921:Dental Implants
keywords: animal study; bone healing; dental implants; histology; implant dentistry; insertion torque; rotational mobility; spin