title: Bone resorption in different parts of the mandible in patients restored with an implant overdenture. A retrospective radiographic analysis.
abstract: OBJECTIVE
  This study investigated the pattern of resorption of the mandibular ridge under implant-supported overdentures.
  
  
  METHODS
  Files of 60 patients were available for analysis (45 women and 15 men, mean age at the time of the follow-up 76.5 ± 8.5 years, 54 patients restored with bars, 6 with ball anchors). A baseline was defined by different stable landmarks and quartered. Linear measurements from this baseline at different clinical relevant sites approximately at: (i) the area close to the mental foramen/close to the implant, (ii) the chewing center, and (iii) the distal edge of the denture flange were carried out on rotational tomograms (OPTs). The OPTs were taken after prosthetic restoration and at an individual follow-up time (mean 11 ± 4.75 years). The known implant length served to scale each measurement to avoid any distortion errors.
  
  
  RESULTS
  The resorption rate showed a high individual variation, but among the three sites, the difference was highly significant. Median values of site (i) left = -0.07 mm/right = +0.05 mm, site (ii) left = -0.60 mm/right = -0.55 mm, and site (iii) left = -1.58 mm/right = -2.01 mm.
  
  
  CONCLUSIONS
  The load of the distal flange of a mandibular implant overdenture increases bone resorption as a local factor, whereas implants may help to prevent resorption in the neighboring bone. An individual-adapted follow-up protocol should be established for each patient restored with an implant overdenture.
authors.affiliation: Department of Prosthodontics, School of Dental Medicine, University of Bern, Bern, Switzerland.
authors.forename: Urs
authors.initials: U
authors.lastname: Kremer
authors.affiliation: Department of Prosthodontics, School of Dental Medicine, University of Bern, Bern, Switzerland.
authors.forename: Sven
authors.initials: S
authors.lastname: Schindler
authors.affiliation: Department of Prosthodontics, School of Dental Medicine, University of Bern, Bern, Switzerland.
authors.forename: Norbert
authors.initials: N
authors.lastname: Enkling
authors.affiliation: Department of Prosthodontics, School of Dental Medicine, University of Bern, Bern, Switzerland.
authors.forename: Andreas
authors.initials: A
authors.lastname: Worni
authors.affiliation: Department of Prosthodontics, School of Dental Medicine, University of Bern, Bern, Switzerland.
authors.forename: Joannis
authors.initials: J
authors.lastname: Katsoulis
authors.affiliation: Department of Prosthodontics, School of Dental Medicine, University of Bern, Bern, Switzerland.
authors.forename: Regina
authors.initials: R
authors.lastname: Mericske-Stern
mesh_terms: D000368:Aged; D016301:Alveolar Bone Loss / Q000000981:diagnostic imaging* / Q000473:pathology*; D001862:Bone Resorption / Q000000981:diagnostic imaging* / Q000473:pathology*; D019094:Dental Prosthesis, Implant-Supported; D003824:Denture, Complete; D003828:Denture, Overlay; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007575:Jaw, Edentulous / Q000534:rehabilitation; D008297:Male; D008334:Mandible / Q000000981:diagnostic imaging* / Q000473:pathology*; D011862:Radiography, Panoramic; D012189:Retrospective Studies
keywords: implant overdenture; mandibular resorption; resorption pattern