title: AICRG, Part II: Crestal bone loss associated with the Ankylos implant: loading to 36 months.
abstract: OBJECTIVE
  The Ankylos endosseous dental implant is a new implant design that will be available in the United States in early 2004. It features an internal tapered abutment connection, a smooth polished collar without threads at the coronal part of the implant body, and a roughened surface with variable threads on the body of the implant fixture. A precise, tapered, conical abutment connection eliminates the microgap often found in 2-stage implant systems. This microgap may allow the accumulation of food debris and bacteria, as well as micromovement between the parts during clinical function, both of which can lead to a localized inflammation and crestal bone loss.
  
  
  OBJECTIVE
  The purpose of this section of the study was to assess any crestal bone loss associated with this new implant.
  
  
  METHODS
  The clinical performance of this new implant design was studied under well-controlled clinical conditions. Over 1500 implants were placed and restored. The vertical crestal bone loss was measured "directly" between the time of implant placement and uncovering, using a periodontal probe. Serial dental radiographs were taken between loading, and the 12-, 24-, and 36-month follow-up visits to determine "indirect" crestal bone loss within a specific period.
  
  
  RESULTS
  Bone loss varied among the participating centers from less than 0.5 mm to 2.0 mm. The largest amount of bone loss occurred between the time of placement and uncovering. Following loading, the mean bone loss for all implants for a period of 3 years was about 0.2 mm/y.
  
  
  CONCLUSIONS
  The extent of the crestal bone loss after loading was minimal for patients regardless of age, gender, prosthetic applications, bone density, and remote or crestal incisions, as well as for smokers or nonsmokers. Bone loss per year is well within the guidelines of 0.2 mm/y proposed by others.
authors.affiliation: Cherng-Tzeh Chou, DDS, is a clinical instructor in the School of Dentistry, Taipei Medical University, Taipei, Taiwan.
authors.forename: Cherng-Tzeh
authors.initials: CT
authors.lastname: Chou
authors.forename: Harold F
authors.initials: HF
authors.lastname: Morris
authors.forename: Shigeru
authors.initials: S
authors.lastname: Ochi
authors.forename: Lori
authors.initials: L
authors.lastname: Walker
authors.forename: Deborah
authors.initials: D
authors.lastname: DesRosiers
mesh_terms: D016301:Alveolar Bone Loss / Q000209:etiology*; D001863:Bone Screws; D000044:Dental Abutments / Q000009:adverse effects*; D003758:Dental Implantation, Endosseous / Q000009:adverse effects*; D015921:Dental Implants / Q000009:adverse effects*; D017267:Dental Prosthesis Design; D019094:Dental Prosthesis, Implant-Supported; D003799:Dental Stress Analysis; D006801:Humans; D008137:Longitudinal Studies; D008875:Middle Aged; D013499:Surface Properties
chemical_list: D015921:Dental Implants