title: Technical and biological complications of single-molar implant restorations.
abstract: OBJECTIVE
  Retrospective evaluation of the biological and technical complications in implant-supported single-tooth molar restorations performed in a private practice after functional periods of ≥4 years.
  
  
  METHODS
  Sixty-five patients (34 females, age 51.7 ± 10.6 years) with 112 implants received annual follow-up examinations and participated in a maintenance program. The survival (in situ) and success (complication-free) rates of implants and superstructures were evaluated. Time-dependent peri-implantitis rates were calculated, and the influencing factors were identified using a multiple Cox regression.
  
  
  RESULTS
  The implant survival rate was 100%. Three of 112 crowns required replacement (prosthetic survival rate = 98.1%). Thirty technical complications were observed: loss of retention (16), ceramic fracture (10), and screw loosening (4). The success rate of the superstructures was 79.0% after 7 years. Overall, 9.2% of the patients developed peri-implantitis (probing depth ≥5 mm, BOP, suppuration, bone loss ≥3.5 mm); (smokers: 41.6%, non-smokers: 1.8%). After 7 years, the time-dependent implant success rate (free of peri-implantitis) was 100% for non-smokers and 58.6% for smokers. Multiple analysis showed a significant effect of smoking (hazard ratio, 19.5; P = 0.008) on peri-implantitis.
  
  
  CONCLUSIONS
  Implants with cemented single-tooth restorations in the molar region constitute a reliable treatment in private practice. Smokers have a significantly increased peri-implantitis rate.
authors.affiliation: Private Practice Hanau, Germany.
authors.forename: Sven
authors.initials: S
authors.lastname: Rinke
authors.affiliation: Department of Prosthodontics, Georg-August-University, Goettingen, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Roediger
authors.affiliation: Department of Periodontology, Center for Dental Medicine, Oral and Maxillofacial Medicine, Johann Wolfgang Goethe-University, Frankfurt/Main, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Eickholz
authors.affiliation: Department of Medical Statistics, Georg-August-University, Goettingen, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Lange
authors.affiliation: Department of Operative Dentistry, Preventive Dentistry and Periodontology, Georg-August-University, Göttingen, Germany.
authors.forename: Dirk
authors.initials: D
authors.lastname: Ziebolz
mesh_terms: D000328:Adult; D003757:Dental Implantation / Q000379:methods*; D019250:Dental Implants, Single-Tooth / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008963:Molar; D057873:Peri-Implantitis / Q000453:epidemiology* / Q000628:therapy*; D011475:Prosthesis Failure; D012189:Retrospective Studies; D012907:Smoking / Q000009:adverse effects
keywords: cement; ceramics; clinical studies; dental implant(s); peri-implant infections(s); tobacco