title: A randomized-controlled trial of low-dose doxycycline for periodontitis in smokers.
abstract: OBJECTIVE
  Tobacco use reduces the effect of non-surgical periodontal therapy. Host-modulation with low-dose doxycycline (LDD) might favour repair and promote an improved treatment response. The aim of this study was to investigate the effect of LDD in smokers on non-surgical periodontal therapy.
  
  
  METHODS
  This was a parallel arm, randomized, identical placebo-controlled trial with masking of examiner, care-giver, participant and statistician and 6 months of follow-up. Patients received non-surgical therapy and 3 months of test or control drug. Statistical analysis used both conventional methods and multilevel modelling.
  
  
  RESULTS
  Eighteen control and 16 test patients completed the study. The velocity of change was statistically greater for the test group for clinical attachment level -0.19 mm/month (95% CI=-0.34, 0.04; p=0.012) and probing depth 0.30 mm/month (95% CI=-0.42, -0.17; p<0.001). However, no differences were observed for absolute change in clinical or biochemical markers at 6 months.
  
  
  CONCLUSIONS
  This study does not provide evidence of a benefit of using LDD as an adjunct to non-surgical periodontal therapy in smokers.
authors.affiliation: Department of Periodontology and International Centre for Evidence-Based Oral Health, UCL Eastman Dental Institute, London, UK. i.needleman@eastman.ucl.ac.uk
authors.forename: Ian
authors.initials: I
authors.lastname: Needleman
authors.forename: Jean
authors.initials: J
authors.lastname: Suvan
authors.forename: Mark S
authors.initials: MS
authors.lastname: Gilthorpe
authors.forename: Richard
authors.initials: R
authors.lastname: Tucker
authors.forename: Geoff
authors.initials: G
authors.lastname: St George
authors.forename: William
authors.initials: W
authors.lastname: Giannobile
authors.forename: Maurizio
authors.initials: M
authors.lastname: Tonetti
authors.forename: Martin
authors.initials: M
authors.lastname: Jarvis
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D024042:Collagen Type I; D012534:Dental Scaling; D004311:Double-Blind Method; D004318:Doxycycline / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000627:therapeutic use; D005260:Female; D005883:Gingival Crevicular Fluid / Q000737:chemistry; D006801:Humans; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D010446:Peptide Fragments / Q000032:analysis; D010455:Peptides; D017622:Periodontal Attachment Loss / Q000188:drug therapy; D010518:Periodontitis / Q000188:drug therapy*; D011347:Procollagen / Q000032:analysis; D011446:Prospective Studies; D012907:Smoking; D016896:Treatment Outcome
chemical_list: D000900:Anti-Bacterial Agents; D024042:Collagen Type I; D010446:Peptide Fragments; D010455:Peptides; D011347:Procollagen; C052929:collagen type I trimeric cross-linked peptide; D004318:Doxycycline