title: Using restorations borne totally by anterior implants to preserve the edentulous mandible.
abstract: BACKGROUND
  This study quantifies the changes in bone height of the posterior area of the edentulous mandible when the load of complete dentures is borne entirely by anteriorly placed osseointegrated implants.
  
  
  METHODS
  Thirty-three patients, of whom there were radiographs from the beginning of implant loading and from a follow-up visit at least three years later (a mean of 6.6 years later), were included in the study. Working with panoramic radiographs, the authors took height measurements in the premolar area (15 millimeters distal to the most distal implants). A valid correction factor was available because implants of known length were proximal to the area being evaluated.
  
  
  RESULTS
  The authors calculated descriptive statistics using means, standard deviations, medians and proportions as appropriate. A P-value of less than .05 was considered significant. Of the 33 subjects, most showed increases in bone height--29 (87.9 percent) on the right side and 28 (84.9 percent) on the left side. The mean change in all subjects was +1.0 mm (range -0.8 to +3.3 mm). A comparison of mandibular height at implant placement vs. follow-up showed a statistically significant increase bilaterally (P < .001).
  
  
  CONCLUSIONS
  This study demonstrates that dentures for edentulous mandibles that are borne totally by implants in the anterior area conserve or enhance the bone of the posterior portion of the mandible. An important future study should test the effect of implant-assisted restorations for the edentulous mandible that load the posterior ridge (a bar clasp, for example).
  
  
  CONCLUSIONS
  One of the considerations in planning treatment for the edentulous mandible should be the preserving effect of totally implant-borne restorations vs. the continued resorption of the body of the mandible with conventional dentures.
authors.affiliation: Department of Oral and Maxillofacial Surgery, University of Southern California, School of Dentistry, Los Angeles, USA.
authors.forename: W H
authors.initials: WH
authors.lastname: Davis
authors.forename: P S
authors.initials: PS
authors.lastname: Lam
authors.forename: M W
authors.initials: MW
authors.lastname: Marshall
authors.forename: W
authors.initials: W
authors.lastname: Dorchester
authors.forename: D A
authors.initials: DA
authors.lastname: Hochwald
authors.forename: R M
authors.initials: RM
authors.lastname: Kaminishi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016301:Alveolar Bone Loss / Q000209:etiology / Q000517:prevention & control*; D001861:Bone Regeneration; D017267:Dental Prosthesis Design; D019094:Dental Prosthesis, Implant-Supported; D003799:Dental Stress Analysis; D003826:Denture, Complete, Lower / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007575:Jaw, Edentulous / Q000534:rehabilitation*; D008297:Male; D008334:Mandible / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D008875:Middle Aged; D011859:Radiography; D012189:Retrospective Studies; D016474:Weight-Bearing