title: Prognosis of the implants replaced after removal of failed dental implants.
abstract: OBJECTIVE
  Dental implant failures occur occasionally, and clinicians may hesitate to perform a second implantation because of the uncertain prognosis. This study was carried out to evaluate the survival rate and condition of tissue surrounding the replaced implants after removal of failed implants.
  
  
  METHODS
  Forty-nine patients (60 implants) who underwent placement of a dental implant between June 2003 and December 2006, who experienced implant failure and underwent a second implantation at Seoul National University Bundang Hospital, were included in this study. We investigated surgery techniques in addition to the healing time after the second implantation, the type of second implantation (immediate or delayed replacement), the survival rate of the replaced dental implants, the crestal bone loss around the implant, and condition of the tissue surrounding the implant at the time of final follow-up.
  
  
  RESULTS
  The most frequent site of implant failure was the maxillary first molar area. The percentages of cases of immediate and delayed replacement were 48.3% and 51.7%, respectively. The average healing time for patients undergoing delayed replacement was 2.40+/-3.06 months. No significant difference in the failure rate of the second implant was observed between the immediate and delayed replacement groups (P>.05). The failure rate of the second implant after removal of failed implant was 11.7%, and a third implantation was performed for all of the failed second implantation cases. The second and third implants all survived until the final follow-up, and thus all patients had a successful implant at the time of the final follow-up. The marginal bone loss at the final follow-up (22.00+/-14.56 months after implantation) was 0.33+/-0.49 mm, the width of attached gingiva was 1.68+/-2.11 mm, the plaque index was 0.81+/-1.05, the gingival index was 0.56+/-0.63, and the pocket depth was 3.33+/-1.21 mm.
  
  
  CONCLUSIONS
  Implant failure occurred most frequently in the maxillary first molar area. We can improve the survival rate of replaced dental implants after removing the initial failed implant using various bone grafting techniques and/or additional implant fixture.
authors.affiliation: Department of Oral and Maxillofacial Surgery, Section of Dentistry, Seoul National University Bundang Hospital, Seoul, Korea.
authors.forename: Young-Kyun
authors.initials: YK
authors.lastname: Kim
authors.forename: Jin-Young
authors.initials: JY
authors.lastname: Park
authors.forename: Su-Gwan
authors.initials: SG
authors.lastname: Kim
authors.forename: Hyo-Jung
authors.initials: HJ
authors.lastname: Lee
mesh_terms: D000328:Adult; D016301:Alveolar Bone Loss / Q000150:complications* / Q000517:prevention & control; D003758:Dental Implantation, Endosseous / Q000379:methods / Q000706:statistics & numerical data*; D015921:Dental Implants / Q000706:statistics & numerical data*; D017267:Dental Prosthesis Design; D019094:Dental Prosthesis, Implant-Supported; D019232:Dental Restoration Failure; D020878:Device Removal; D006801:Humans; D008297:Male; D008437:Maxilla; D008875:Middle Aged; D008963:Molar; D011379:Prognosis; D019233:Retreatment / Q000706:statistics & numerical data; D015996:Survival Rate
chemical_list: D015921:Dental Implants