title: Influence of early cover screw exposure on crestal bone loss around implants: intraindividual comparison of bone level at exposed and non-exposed implants.
abstract: BACKGROUND
  The objective of this study was to evaluate the influence of early exposure of the cover screw on crestal bone loss around implants.
  
  
  METHODS
  The study population consisted of 19 patients who were treated with dental implants placed using a two-stage surgical protocol and had early exposed and non-exposed implants (20 early exposed and 20 non-exposed implants). The crestal bone loss at exposed and non-exposed implants in each patient was evaluated with a periapical radiograph taken at the first surgery and at suprastructure insertion using a computerized image-analysis system. The bone loss was compared using the Wilcoxon signed-rank test.
  
  
  RESULTS
  The mean crestal bone loss at exposed implants was 0.40 +/- 0.53 mm, and it was 0.18 +/- 0.26 mm at non-exposed implants. The Wilcoxon signed-rank test revealed a statistically significant difference in crestal bone loss between exposed and non-exposed implants in the same patient (P = 0.02).
  
  
  CONCLUSIONS
  The early exposure of the cover screw that results in breakdown of the mucosal seal seems to accelerate early peri-implant crestal bone loss. Periodic follow-up after the first surgery may be critical for minimizing the influence of early exposure.
authors.affiliation: Department of Periodontology, Gangnam Severance Dental Hospital, College of Dentistry, Yonsei University, Seoul, Korea.
authors.forename: Tae-Hyung
authors.initials: TH
authors.lastname: Kim
authors.forename: Dong-Won
authors.initials: DW
authors.lastname: Lee
authors.forename: Chong-Kwan
authors.initials: CK
authors.lastname: Kim
authors.forename: Kwang-Ho
authors.initials: KH
authors.lastname: Park
authors.forename: Ik-Sang
authors.initials: IS
authors.lastname: Moon
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016301:Alveolar Bone Loss / Q000209:etiology*; D000044:Dental Abutments; D003758:Dental Implantation, Endosseous / Q000295:instrumentation* / Q000379:methods; D015921:Dental Implants; D005260:Female; D005500:Follow-Up Studies; D005881:Gingiva / Q000473:pathology* / Q000601:surgery; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D016348:Osseointegration / Q000502:physiology; D016300:Radiography, Bitewing; D013529:Surgical Wound Dehiscence / Q000150:complications; D020390:Tooth Socket / Q000601:surgery; D014945:Wound Healing
chemical_list: D015921:Dental Implants