title: Effect of smoking on the failure rates of orthodontic miniscrews.
abstract: OBJECTIVE
  The aim of this study was to investigate the effect of cigarette smoking on the failure rates of orthodontic miniscrews.
  
  
  METHODS
  Our cohort consisted of 88 patients with a total of 110 orthodontic miniscrews. Based on their smoking habits, the patients were divided into three groups: the light smokers (< or = 10 cigarettes/day), heavy smokers (> 10 cigarettes/ day), and non-smokers. The light-smoker group consisted of 14 patients with 18 orthodontic miniscrews, and there were 15 patients with 19 miniscrews among the heavy smokers. The nonsmoker group contained 59 patients with a total of 73 miniscrews.
  
  
  RESULTS
  The overall failure rate was 18.2% (n = 20). Heavy smokers revealed a significantly higher failure rate than light smokers (p = 0.005) or non-smokers (p < 0.001). No significant differences were observed between non-smokers and light smokers. Miniscrews in the heavy smoker group exhibited a significantly higher failure rate during the first 4 months after insertion than did the miniscrews in the light smokers (p = 0.008) or non-smokers (p < 0.001).
  
  
  CONCLUSIONS
  Our results suggest that heavy smoking has a detrimental effect on the success rates of orthodontic miniscrews.
authors.affiliation: Private Practice Hannover, Hannover, Germany.
authors.forename: Emad
authors.initials: E
authors.lastname: Bayat
authors.forename: Oskar
authors.initials: O
authors.lastname: Bauss
mesh_terms: D000293:Adolescent; D000328:Adult; D001863:Bone Screws / Q000706:statistics & numerical data*; D015984:Causality; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D052280:Orthodontic Anchorage Procedures / Q000295:instrumentation* / Q000706:statistics & numerical data*; D011475:Prosthesis Failure; D018570:Risk Assessment; D012307:Risk Factors; D012907:Smoking / Q000453:epidemiology*; D055815:Young Adult