title: Preliminary 2-year report on treatment outcomes for 6-mm-long implants in posterior atrophic mandibles.
abstract: OBJECTIVE
  The aim of this study was to prospectively evaluate clinical and radiographic outcomes of ultrashort implants (4-mm diameter, 6-mm length) supporting fixed partial dentures in severely atrophic posterior mandibles.
  
  
  METHODS
  Twenty-five patients with posterior edentulous mandibular spans and 7- to 8-mm residual bone heights above the mandibular canal were enrolled. In total, 61 submerged implants were placed and loaded 5 to 6 months later. Patients were followed for 2 years after prosthesis connection with clinical, radiographic, and resonance frequency analysis (RFA) examinations.
  
  
  RESULTS
  Two implants failed in one patient before loading; all other implants showed favorable clinical and radiographic findings throughout the observation period (2-year survival and success rate: 96.8%). Postoperative pain and swelling were negligible. Mean changes in marginal bone levels were stable (0.40 ± 0.23, 0.51 ± 0.38, and 0.60 ± 0.13 mm after 6 months and 1 and 2 years, respectively) and were unaffected by measured crown-to-implant ratios (range: 1.31 to 3.12). Mean RFA values increased significantly from implant placement (67.35 ± 6.67) to 2 years (72.91 ± 5.07, P < .0001). Prosthetic complications included two prosthesis decementations, three ceramic veneer chippings, and one prosthesis screw loosening.
  
  
  CONCLUSIONS
  Within the limitations of the short follow-up period, the use of 6-mm-long implants was a predictable treatment method for patients with atrophic posterior mandibles and increased crown-to-implant ratios.
authors.affiliation: Department of Dental Sciences, University of Bologna, Bologna, Italy. checcopieri@yahoo.it
authors.forename: Francesco
authors.initials: F
authors.lastname: Pieri
authors.forename: Nicolo Nicoli
authors.initials: NN
authors.lastname: Aldini
authors.forename: Milena
authors.initials: M
authors.lastname: Fini
authors.forename: Claudio
authors.initials: C
authors.lastname: Marchetti
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Corinaldesi
mesh_terms: D000368:Aged; D016301:Alveolar Bone Loss / Q000000981:diagnostic imaging / Q000473:pathology*; D001641:Bicuspid; D016009:Chi-Square Distribution; D003758:Dental Implantation, Endosseous / Q000379:methods*; D015921:Dental Implants; D017267:Dental Prosthesis Design; D019232:Dental Restoration Failure; D003830:Denture, Partial, Fixed; D004487:Edema; D005260:Female; D006801:Humans; D008297:Male; D008334:Mandible / Q000601:surgery; D008336:Mandibular Diseases / Q000000981:diagnostic imaging / Q000473:pathology; D008875:Middle Aged; D008963:Molar; D010149:Postoperative Pain; D017060:Patient Satisfaction; D011446:Prospective Studies; D019252:Radiography, Dental, Digital; D018709:Statistics, Nonparametric; D011795:Surveys and Questionnaires; D016896:Treatment Outcome
chemical_list: D015921:Dental Implants