title: Biomechanical evaluation of endosseous implants at early implantation times: a study in dogs.
abstract: OBJECTIVE
  This study tested the null hypothesis that differences in surgical instrumentation, macrogeometry, and surface treatment imposed by different implant systems do not affect early biomechanical fixation in a canine mandible model.
  
  
  METHODS
  The lower premolars of 6 beagle dogs were extracted and the ridges allowed to heal for 8 weeks. Thirty-six (n = 12 each group) implants were bilaterally placed, remaining for 1 and 3 weeks in vivo. The implant groups were as follows: group 1, Ti-6Al-4V with a dual acid-etched surface with nanometer scale discrete crystalline deposition (Nanotite; Certain Biomet-3i, West Palm Springs, FL); group 2, Ti-6Al-4V with a titanium oxide-blasted fluoride-modified surface chemistry (Osseospeed 4.0 S; Astra Tech, Mölndal, Sweden); group 3: Ti-6Al-4V with a bioceramic microblasted surface (Ossean; Intra-Lock International, Boca Raton, FL). Following euthanasia, implants were torqued to interface failure and histologically evaluated. General linear modeling (ANOVA) at 95% level of significance was performed.
  
  
  RESULTS
  Histology showed that interfacial bone remodeling and initial woven bone formation were observed around all implant groups at 1 and 3 weeks. Torque values were significantly affected by time in vivo, implant group, and their interaction (P = .016, P < .001, and P = .001, respectively). Regarding torque values, group 3, group 2, and group 1 ranked highest, intermediate, and lowest, respectively.
  
  
  CONCLUSIONS
  Early biomechanical fixation at 1 and 3 weeks was affected by surgical instrumentation, macrogeometry, and surface treatment present for one of the implant systems tested. The null hypothesis was rejected.
authors.affiliation: Department of Biomaterials and Biomimetics, New York University, New York, NY 10010, USA. pgcoelho@nyu.edu
authors.forename: Paulo G
authors.initials: PG
authors.lastname: Coelho
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Granato
authors.forename: Charles
authors.initials: C
authors.lastname: Marin
authors.forename: Estevam A
authors.initials: EA
authors.lastname: Bonfante
authors.forename: Jose N O
authors.initials: JN
authors.lastname: Freire
authors.forename: Malvin N
authors.initials: MN
authors.lastname: Janal
authors.forename: Jose N
authors.initials: JN
authors.lastname: Gil
authors.forename: Marcelo
authors.initials: M
authors.lastname: Suzuki
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001696:Biomechanical Phenomena; D016723:Bone Remodeling; D003758:Dental Implantation, Endosseous / Q000295:instrumentation / Q000379:methods*; D015921:Dental Implants; D017267:Dental Prosthesis Design; D017268:Dental Prosthesis Retention; D003799:Dental Stress Analysis; D004285:Dogs; D016014:Linear Models; D016348:Osseointegration; D013499:Surface Properties; D013997:Time Factors; D019415:Torque
chemical_list: D015921:Dental Implants