title: Ridge width gain with screw spreaders: a cadaver study.
abstract: BACKGROUND
  The aim of this cadaver study was to evaluate the amount of ridge expansion with screw spreaders.
  
  
  METHODS
  Eleven edentulous maxillae providing 20 eligible sites were used. Ridges with initial width of 3 to 6 mm were expanded using a set of 6 screw spreaders, and implants (ø3.7 × 10 mm) were subsequently placed. Ridge width at 2 mm apical to the crest was measured at the baseline, after expansion, and implant placement. Buccal plate thickness and incidence of buccal dehiscence after implant placement were measured.
  
  
  RESULTS
  The mean initial ridge width was 3.97 ± 0.82 mm. After the expansion, the mean ridge width increased to 4.76 ± 0.77 mm (Δ = 0.79 mm). Majority of sites (7/9 sites) with an initial ridge width of <4 mm had a buccal dehiscence after implant placement. A buccal plate thickness of ≥1 mm was consistently present in cases with an initial ridge width of ≥4.5 mm after implant placement.
  
  
  CONCLUSIONS
  The screw spreaders had a modest effect on ridge expansion. Their use might be limited because additional bone augmentation might be required to prevent or correct the bony dehiscence encountered in ridges <4.5 mm wide. Therefore, using this particular instrument kit for horizontal ridge augmentation is only indicated in specific cases.
authors.affiliation: *Clinical Adjunct Assistant Professor, Department of Periodontics and Oral Medicine, School of Dentistry, University of Michigan, Ann Arbor, MI. †Assistant Professor, Department of Preventive Dentistry (Periodontology) at the Faculty of Dentistry, National University of Singapore, Singapore. ‡Resident, Department of Periodontics and Oral Medicine, School of Dentistry, University of Michigan, Ann Arbor, MI. §Clinical Assistant Professor, Department of Periodontics and Oral Medicine, School of Dentistry, University of Michigan, Ann Arbor, MI. ‖Professor and Director, Department of Periodontics and Oral Medicine, School of Dentistry, University of Michigan, Ann Arbor, MI.
authors.forename: Hsun-Liang
authors.initials: HL
authors.lastname: Chan
authors.forename: Jia-Hui
authors.initials: JH
authors.lastname: Fu
authors.forename: Tapan
authors.initials: T
authors.lastname: Koticha
authors.forename: Erika
authors.initials: E
authors.lastname: Benavides
authors.forename: Hom-Lay
authors.initials: HL
authors.lastname: Wang
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000539:Alveolar Process / Q000601:surgery; D000540:Alveolar Ridge Augmentation / Q000295:instrumentation / Q000379:methods*; D003758:Dental Implantation, Endosseous / Q000295:instrumentation / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008437:Maxilla / Q000601:surgery; D008875:Middle Aged; D013529:Surgical Wound Dehiscence / Q000209:etiology