title: Dental implant thread pitch and its influence on the osseointegration process: an in vivo comparison study.
abstract: OBJECTIVE
  The design of an implant plays a fundamental role in the osseointegration process, particularly in low-density bone. It has been postulated that design features that maximize the surface area available for contact may improve mechanical anchorage and primary stability in cancellous bone. Two different implant profiles were compared to evaluate the influence of thread pitch on the osseointegration process in bone of low density and limited height.
  
  
  METHODS
  "Narrow-pitch" implants (NP) with a 0.5-mm pitch and "wide-pitch" implants (WP) with a 1.7-mm pitch were tested for osseointegration after 0 days and 4 and 8 weeks in a sheep iliac crest model. The two different implants were analyzed with biologic and biomechanical tests.
  
  
  RESULTS
  The present findings showed that initial mechanical anchorage and subsequent early endosseous integration in low-density bone could be improved by a reduction of thread pitch. The greater surface area gained by decreasing thread pitch increased bone-implant contact and primary stability from the time of implant placement. This better performance of the NP profile could be appreciated even at an early healing time when the subsequent biologic integration was enhanced not only in terms of a higher quantity of newly deposited bone but also more regular and mature geometric distribution of bone tissue at the interface.
  
  
  CONCLUSIONS
  These results confirmed that, when primary stability is a concern, as in cancellous bone, increasing the implant surface area by using implants with smaller pitch might be beneficial.
authors.affiliation: Department of Human Anatomical Sciences and Physiopathology of Locomotor Apparatus, University of Bologna, Bologna, Italy. ester.orsini@unibo.it
authors.forename: Ester
authors.initials: E
authors.lastname: Orsini
authors.forename: Gianluca
authors.initials: G
authors.lastname: Giavaresi
authors.forename: Alessandra
authors.initials: A
authors.lastname: Trirè
authors.forename: Vittoria
authors.initials: V
authors.lastname: Ottani
authors.forename: Stefano
authors.initials: S
authors.lastname: Salgarello
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D000537:Aluminum Oxide / Q000737:chemistry; D000818:Animals; D001696:Biomechanical Phenomena; D015519:Bone Density / Q000502:physiology; D001857:Bone Matrix / Q000473:pathology; D045662:Dental Etching / Q000379:methods; D003758:Dental Implantation, Endosseous / Q000379:methods; D015921:Dental Implants; D003764:Dental Materials / Q000737:chemistry; D017267:Dental Prosthesis Design; D017268:Dental Prosthesis Retention; D007085:Ilium / Q000473:pathology / Q000601:surgery; D008855:Microscopy, Electron, Scanning; D016348:Osseointegration / Q000502:physiology*; D010012:Osteogenesis / Q000502:physiology; D010027:Osteotomy / Q000379:methods; D012756:Sheep; D013499:Surface Properties; D013997:Time Factors; D014025:Titanium / Q000737:chemistry; D019415:Torque
chemical_list: D015921:Dental Implants; D003764:Dental Materials; D014025:Titanium; D000537:Aluminum Oxide