title: Bone stability around implants in elderly patients with reduced bone mineral density - a prospective study on mandibular overdentures.
abstract: OBJECTIVE
  The purpose of this prospective clinical study was to determine whether reduced bone mineral density (BMD) is correlated with a higher risk for dental implant therapy in an elderly patient population.
  
  
  METHODS
  Seventy-nine patients recruited at the Prince Philip Dental Hospital were provided with 2-implant-supported mandibular overdentures. Skeletal BMD was recorded before the implant therapy. The World Health Organization Osteoporosis Diagnosis Classification (femoral neck score) was utilized to define the osteoporosis status of patients. Periapical radiographs were taken with a special radiographic holder at the time of implant loading (baseline) and at follow-up examinations. The mesial and distal marginal bone levels of each implant were measured. The mean marginal bone loss (mMBL) and greatest marginal bone loss (GBL) of four implant sites at patient level were recorded for data analysis. Clinical examination including plaque score (PI) and bleeding on probing (BOP) was recorded.
  
  
  RESULTS
  Of the 79 patients recruited in the study, the survival rate of implant was 98.7%. Sixty-three patients (79.7%) were finally available for data collection and statistical analyses. The mean follow-up time was 62.9 (SD = 15.2) months with the mean MBL 0.65 mm (SD = 0.67) and mean GBL 1.25 mm (SD = 0.83), respectively. The average BOP and PI of patients were 49.6% (SD = 30.8) and 47.4% (SD = 37.4). Only BOP was found significantly correlated with mMBL (r = 0.321, P = 0.01). Skeletal BMD was not associated with marginal bone loss (mean MBL: r = -0.094, P = 0.466; mean GBL: r = 0.04, P = 0.761).
  
  
  CONCLUSIONS
  Within the limits of this study, osteoporosis was not a contraindication for implant therapy, and reduced skeletal BMD was not associated with increased marginal bone loss around implants or other complications in an elderly population.
authors.affiliation: The Faculty of Dentistry, University of Hong Kong, Hong Kong, China.
authors.forename: Luke
authors.initials: L
authors.lastname: Chow
authors.affiliation: The Faculty of Dentistry, University of Hong Kong, Hong Kong, China.
authors.forename: Tak Wah
authors.initials: TW
authors.lastname: Chow
authors.affiliation: The Faculty of Dentistry, University of Hong Kong, Hong Kong, China.
authors.forename: John
authors.initials: J
authors.lastname: Chai
authors.affiliation: The Faculty of Dentistry, University of Hong Kong, Hong Kong, China.
authors.forename: Nikos
authors.identifier: http://orcid.org/0000-0001-7358-7496
authors.initials: N
authors.lastname: Mattheos
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016301:Alveolar Bone Loss / Q000473:pathology; D015519:Bone Density; D003758:Dental Implantation, Endosseous / Q000379:methods; D019094:Dental Prosthesis, Implant-Supported; D019232:Dental Restoration Failure; D003828:Denture, Overlay; D005260:Female; D006801:Humans; D008297:Male; D008334:Mandible / Q000473:pathology*; D010024:Osteoporosis / Q000473:pathology* / Q000601:surgery; D011446:Prospective Studies
keywords: implant; osteopenia; osteoporosis; overdenture; success; survival