title: Immediate implant placement in molar regions: risk factors for early failure.
abstract: OBJECTIVE
  To identify risk factors for early failure of immediately placed implants in molar regions associated with three bone regenerative techniques.
  
  
  METHODS
  Ninety-two patients (44 women and 48 men; mean age 50 years, 35 smokers and 57 non-smokers) in need of a single implant crown to replace a molar were included. After placing the implant, patients were randomized to one of three treatment groups for bone reconstruction of remaining periimplant defects: Autologous bone (AB) chips, Ossix membrane (OM) or a combination of AB chips and OM. The implant was submerged, and after 4 months of healing a re-entry surgery was made to connect a healing abutment. Implants with a dehiscence on ≥2 sites (mesial/distal/oral/buccal) together with ≥50% visible threads, were judged as failures. A series of simple logistic regression analyses were performed to identify risk factors for failure among the following independent variables: sex, jaw, smoking status, plaque, bleeding on probing, fistula, extraction reason, mean initial periimplant defect size, treatment group, implant length, buccal bone dehiscence (BBD), soft-tissue dehiscence and infection. The identified risk factors entered a multiple logistic regression analysis.
  
  
  RESULTS
  Fifteen implants failed before abutment operation (13 explantations/two non-osseointegrated). Treatment group had no impact on failure. Risk factors for failure were: Smoking >10 cigarettes/day (odds ratio [OR]=9.29, confidence interval [CI]=1.21-71.16), BBD (OR=11.43, CI=1.34-97.74) and infection (OR=36.7, CI=2.75-489.31).
  
  
  CONCLUSIONS
  Implants placed immediately after extraction of a molar were associated with a high risk for failure at abutment operation. There was no difference in failure rate between three bone reconstructive techniques.
authors: Department of Oral Radiology and Department of Oral & Maxillofacial Surgery, School of Dentistry, Aarhus University, Aarhus C, DenmarkPrivate Practice, Aabyhoej, DenmarkDepartment of Oral Radiology, School of Dentistry, Aarhus University, Aarhus C, Denmark.
authors: Thomas
authors: T
authors: Urban
authors: Department of Oral Radiology and Department of Oral & Maxillofacial Surgery, School of Dentistry, Aarhus University, Aarhus C, DenmarkPrivate Practice, Aabyhoej, DenmarkDepartment of Oral Radiology, School of Dentistry, Aarhus University, Aarhus C, Denmark.
authors: Lambros
authors: L
authors: Kostopoulos
authors: Department of Oral Radiology and Department of Oral & Maxillofacial Surgery, School of Dentistry, Aarhus University, Aarhus C, DenmarkPrivate Practice, Aabyhoej, DenmarkDepartment of Oral Radiology, School of Dentistry, Aarhus University, Aarhus C, Denmark.
authors: Ann
authors: A
authors: Wenzel
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D016025:Bone Transplantation / Q000379:methods; D003094:Collagen; D003442:Crowns; D000044:Dental Abutments; D003758:Dental Implantation, Endosseous / Q000379:methods*; D019250:Dental Implants, Single-Tooth; D019232:Dental Restoration Failure; D005260:Female; D006801:Humans; D057893:Immediate Dental Implant Loading; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D008963:Molar / Q000601:surgery; D057873:Peri-Implantitis / Q000150:complications; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects; D013529:Surgical Wound Dehiscence / Q000150:complications; D014182:Transplantation, Autologous
chemical_list: C551508:Ossix; D003094:Collagen