title: A 10-year prospective study of ITI dental implants placed in the posterior region. II: Influence of the crown-to-implant ratio and different prosthetic treatment modalities on crestal bone loss.
abstract: OBJECTIVE
  To evaluate the influence of the crown-to-implant ratio (C/I) ratio and different implant prosthetic treatment modalities on crestal bone loss around dental implants placed in the posterior region.
  
  
  METHODS
  A total of 192 ITI dental implants were consecutively placed in premolars and molars of 83 partially edentulous patients. All implants were restored by means of ceramic-to-metal fused fixed partial dentures or a single crown. Patients were followed as part of a prospective longitudinal study focusing on implant success. Surgical, radiographic and clinical variables were collected at the 1-year recall after implant placement and at the most recent clinical evaluation. Radiographic parameters were evaluated on periapical radiographs taken with a standardized long-cone paralleling technique. Implant restorations were divided into three groups according to their respective clinical C/I ratios: (a) 0-0.99, (b) 1-1.99 and (c) >or=2.
  
  
  RESULTS
  The mean clinical C/I ratio was 1.77+/-0.56 mm. A total of 51 implants (26.5%) showed a clinical C/I ratio equal to or greater than 2. In this group, three implants failed, giving a cumulative survival rate of 94.1%. Crestal bone loss was -0.34+/-0.27 mm in group a, -0.03+/-0.15 mm in group b and -0.02+/-0.26 mm in group c. Differences among groups were statistically significant (P=0.009). Mode of retention, splinting or presence of cantilever extensions did not have an effect on crestal bone loss around ITI dental implants.
  
  
  CONCLUSIONS
  Implant restorations with C/I ratios between 2 and 3 may be successfully used in the posterior areas of the jaw.
authors: Department of Fixed Prosthodontics and Occlusion, Geneva Dental School, Geneva, Switzerland.
authors: Rafael Juan
authors: RJ
authors: Blanes
authors: Jean Pierre
authors: JP
authors: Bernard
authors: Zulema Maria
authors: ZM
authors: Blanes
authors: Urs Christoph
authors: UC
authors: Belser
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016301:Alveolar Bone Loss / Q000000981:diagnostic imaging / Q000209:etiology; D000704:Analysis of Variance; D001641:Bicuspid; D003442:Crowns; D003758:Dental Implantation, Endosseous / Q000295:instrumentation / Q000379:methods*; D019250:Dental Implants, Single-Tooth / Q000009:adverse effects* / Q000706:statistics & numerical data; D017267:Dental Prosthesis Design; D017268:Dental Prosthesis Retention; D019094:Dental Prosthesis, Implant-Supported; D019232:Dental Restoration Failure; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007576:Jaw, Edentulous, Partially / Q000000981:diagnostic imaging / Q000534:rehabilitation / Q000601:surgery; D008297:Male; D008875:Middle Aged; D008963:Molar; D010512:Periodontal Index; D011446:Prospective Studies; D011859:Radiography; D012737:Sex Factors; D016896:Treatment Outcome; D016474:Weight-Bearing