title: Early bone healing and biomechanical fixation of dual acid-etched and as-machined implants with healing chambers: an experimental study in dogs.
abstract: OBJECTIVE
  To evaluate the biomechanical fixation, bone-to-implant contact (BIC), and bone morphology of screw-type root-form implants with healing chambers with as-machined or dual acid-etched (DAE) surfaces in a canine model.
  
  
  METHODS
  The animal model included the placement of machined (n = 24) and DAE (n = 24) implants along the proximal tibiae of six mongrel dogs, which remained in place for 2 or 4 weeks. Following euthanasia, half of the specimens were subjected to biomechanical testing (torque to interface failure) and the other half were processed for histomorphologic and histomorphometric (%BIC) assessments. Statistical analyses were performed by one-way analysis of variance at the 95% confidence level and the Tukey post hoc test for multiple comparisons.
  
  
  RESULTS
  At 4 weeks, the DAE surface presented significantly higher mean values for torque to interface failure overall. A significant increase in %BIC values occurred for both groups over time. For both groups, bone formation through the classic appositional healing pathway was observed in regions where intimate contact between the implant and the osteotomy walls occurred immediately after implantation. Where contact-free spaces existed after implantation (healing chambers), an intramembranous-like healing mode with newly formed woven bone prevailed.
  
  
  CONCLUSIONS
  In the present short-term evaluation, no differences were observed in BIC between groups; however, an increase in biomechanical fixation was seen from 2 to 4 weeks with the DAE surface.
authors.affiliation: Department of Prosthodontics, University of São Paulo, Bauru School of Dentistry, Bauru, Brazil. estevamab@gmail.com
authors.forename: Estevam A
authors.initials: EA
authors.lastname: Bonfante
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Granato
authors.forename: Charles
authors.initials: C
authors.lastname: Marin
authors.forename: Marcelo
authors.initials: M
authors.lastname: Suzuki
authors.forename: Sergio R
authors.initials: SR
authors.lastname: Oliveira
authors.forename: Gabriela
authors.initials: G
authors.lastname: Giro
authors.forename: Paulo G
authors.initials: PG
authors.lastname: Coelho
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods*; D000818:Animals; D001696:Biomechanical Phenomena; D003722:Dental Alloys / Q000737:chemistry*; D003758:Dental Implantation, Endosseous; D017267:Dental Prosthesis Design; D019232:Dental Restoration Failure; D004285:Dogs; D008297:Male; D023421:Models, Animal; D016348:Osseointegration / Q000502:physiology*; D010012:Osteogenesis / Q000502:physiology; D013499:Surface Properties; D013977:Tibia / Q000473:pathology*; D013997:Time Factors; D014025:Titanium / Q000737:chemistry; D019415:Torque; D014945:Wound Healing / Q000502:physiology
chemical_list: D003722:Dental Alloys; D014025:Titanium