title: Bisphosphonates as a risk factor for adverse orthodontic outcomes: a retrospective cohort study.
abstract: BACKGROUND
  Bisphosphonates are a class of drugs commonly prescribed to treat osteoporosis. They act by decreasing the resorption of bone. Since tooth movement depends on bone remodeling, these drugs can impact orthodontic treatment. The purpose of this study was to evaluate the extent to which bisphosphonate therapy is a risk factor for poor orthodontic outcomes.
  
  
  METHODS
  Orthodontists were invited to participate in the study by performing case reviews of women over age 50 who were treated from 2002 through 2008. Women who used bisphosphonates were compared with women who did not have a history of bisphosphonate use. Outcomes assessed included treatment time, osteonecrosis of the jaws, incisor alignment, incomplete space closure, and root parallelism.
  
  
  RESULTS
  The records for 20 subjects with bisphosphonate exposure were collected, as well as records for 93 subjects without bisphosphonate exposure. In patients undergoing extractions, treatment times were significantly longer if they had a history of bisphosphonate use. No occurrences of osteonecrosis of the jaws were reported, nor did patients end treatment with incisor alignment discrepancies greater than 1 mm, regardless of bisphosphonate exposure. Among patients with extractions or initial spacing, there were higher odds of incomplete space closure (odds ratio, 13) and poor root parallelism (odds ratio, 26) at the end of treatment for patients using bisphosphonates.
  
  
  CONCLUSIONS
  Bisphosphonate use is associated with longer treatment times among extraction patients, increased odds of poor space closure, and increased odds of poor root parallelism.
authors.affiliation: Department of Orthodontics, University of Washington, Seattle, WA, USA. lotwala@u.washington.edu
authors.forename: Raj B
authors.initials: RB
authors.lastname: Lotwala
authors.forename: Geoffrey M
authors.initials: GM
authors.lastname: Greenlee
authors.forename: Susan M
authors.initials: SM
authors.lastname: Ott
authors.forename: Stanton H
authors.initials: SH
authors.lastname: Hall
authors.forename: Greg J
authors.initials: GJ
authors.lastname: Huang
mesh_terms: D050071:Bone Density Conservation Agents / Q000009:adverse effects*; D016009:Chi-Square Distribution; D015331:Cohort Studies; D004164:Diphosphonates / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007180:Incisor / Q000473:pathology; D008875:Middle Aged; D016017:Odds Ratio; D019516:Orthodontic Space Closure; D015663:Osteoporosis, Postmenopausal / Q000188:drug therapy; D012189:Retrospective Studies; D012307:Risk Factors; D011795:Surveys and Questionnaires; D013997:Time Factors; D014081:Tooth Extraction; D014087:Tooth Movement Techniques; D014092:Tooth Root / Q000473:pathology; D017211:Treatment Failure
chemical_list: D050071:Bone Density Conservation Agents; D004164:Diphosphonates