title: Partially Biodegradable Distraction Implant to Replace Conventional Implants in Alveolar Bone of Insufficient Height: A Preliminary Study in Dogs.
abstract: BACKGROUND
  Dental implants have been widely used in the last few decades. However, patients with insufficient bone height need reconstructive surgeries before implant insertion. The distraction implant (DI) has been invented to simplify the treatment procedure, but the shortcomings of DIs have limited their clinical use. We incorporated biodegradable polyester into a novel DI called the partially biodegradable distraction implant (PBDI).
  
  
  OBJECTIVE
  The purpose of this study was to assess the radiological, histological, and biomechanical properties of the PBDI in animal models.
  
  
  METHODS
  PBDIs were manufactured and inserted into the atrophied mandibles of nine dogs. Box-shaped alveolar bones were segmented and distracted. The dogs were randomly divided into three groups that were sacrificed 1, 2, and 3 months after the implant insertion. Actual augmentation height (AAH) of the bone segments was measured to evaluate the effect of distraction. X-ray examination and micro-CT reconstruction and analysis were used to evaluate the regenerated bone in the distraction gap and bone around the functional element. Histological sections were used to evaluate the osseointegration and absorption of the PBDI. Fatigue tests were used to evaluate the biomechanical properties of the PBDI.
  
  
  RESULTS
  Little change was found in AAH among the three groups. X-ray examination and micro-CT reconstruction showed good growth of regenerated bone in the distraction gap. Alveolar bone volume around the functional element increased steadily. No obvious bone absorption occurred in the alveolar crest around PBDI. Three months after distraction, the functional element achieved osseointegration, and the support element began to be absorbed. All PBDIs survived the fatigue test.
  
  
  CONCLUSIONS
  The PBDI is a novel and reliable dental implant. It becomes a conventional implant after the absorption of the support element and the removal of the distraction screw. It is a promising replacement for conventional implants in patients with insufficient alveolar bone height.
authors.affiliation: State Key Laboratory of Military Stomatology, Department of Orthodontics, School of Stomatology, Fourth Military Medical University, Xi'an, China.|Department of Stomatology, PLA Second Artillery General Hospital, Beijing, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Li
authors.affiliation: State Key Laboratory of Military Stomatology, Department of Oral and Maxillofacial Surgery, School of Stomatology, Fourth Military Medical University, Xi'an, China.
authors.forename: Yongqiang
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Military Stomatology, Department of Oral and Maxillofacial Surgery, School of Stomatology, Fourth Military Medical University, Xi'an, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Shao
authors.affiliation: Department of Stomatology, No. 263 Clinical Section of the General Hospital of Beijing Military Region, Beijing, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Gao
authors.affiliation: Department of Neurology, PLA Second Artillery General Hospital, Beijing, China.
authors.forename: Chen
authors.initials: C
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Military Stomatology, Department of Oral and Maxillofacial Surgery, School of Stomatology, Fourth Military Medical University, Xi'an, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Cao
authors.affiliation: State Key Laboratory of Military Stomatology, Department of Oral and Maxillofacial Surgery, School of Stomatology, Fourth Military Medical University, Xi'an, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Kong
mesh_terms: D020341:Absorbable Implants; D000539:Alveolar Process / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D000818:Animals; D001696:Biomechanical Phenomena; D003758:Dental Implantation, Endosseous / Q000379:methods*; D015921:Dental Implants; D003799:Dental Stress Analysis; D004285:Dogs; D020007:Implants, Experimental; D008334:Mandible / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D023421:Models, Animal; D016348:Osseointegration; D019857:Osteogenesis, Distraction / Q000379:methods*; D011091:Polyesters; D011897:Random Allocation; D055114:X-Ray Microtomography
chemical_list: D015921:Dental Implants; D011091:Polyesters
keywords: animal study; atrophy; biomaterials; implant design; implant stability