title: Scanning electron microscopy observations of osseointegration failures of dental implants that support mandibular overdentures.
abstract: OBJECTIVE
  : Investigating possible failure causes of mandibular implants after their immediate loading with an overdenture retained with bilateral bar attachments, using scanning electron microscope.
  
  
  METHODS
  Twenty edentulous male patients were included in the present study. Each patient had 2 fixtures inserted in the canine and the first molar areas on each side of the mandible. After abutments screwing, the 2 fixtures on the same side were splinted with a bar, and immediately loaded with an overdenture. Implants mobility was assessed on weekly basis. Failed implants were removed, and examined by scanning electron microscope.
  
  
  RESULTS
  The failed implants, removed after 4 weeks of treatment, showed an intimate contact of mineralized and osteoid tissues with dense collagen-rich matrix in the apical third of implants. Furthermore, newly developed bone was observed at the same area in implants removed after 7 weeks. However, there was no evidence of such growth at the middle and/or cervical thirds in either case.
  
  
  CONCLUSIONS
  Lack of osseointegration at the middle and cervical thirds of the root could be a possible cause of implant failure. Early loading by an overdenture retained with bilateral bars is considered a major contributing factor to incomplete osseointegration of the supporting implants.
authors.affiliation: *Assistant Professor, Department of Removable Prosthodontics, Faculty of Dentistry, Mansoura University, Mansoura, Egypt. †Associate Professor, Department of Removable Prosthodontics, Faculty of Dentistry, Mansoura University, Mansoura, Egypt. ‡Associate Professor, Department of Oral Biology, Faculty of Dentistry, Mansoura University, Mansoura, Egypt. §Professor, Department of Oral Medicine and Periodontology, Faculty of Dentistry, Mansoura University, Mansoura, Egypt. ‖Post Doctoral Research Fellow, WELMEC, Center of Excellence in Medical Engineering, Department Of Oral Biology, Leeds Dental Institute, Leeds University, United Kingdom; Assistant Lecturer, Department of Oral Pathology, Faculty of Dentistry, Suez Canal University.
authors.forename: Nesreen
authors.initials: N
authors.lastname: El-Mekawy
authors.forename: Mohammed M
authors.initials: MM
authors.lastname: Fouad
authors.forename: Youssry M
authors.initials: YM
authors.lastname: El-Hawary
authors.forename: Mohamad A
authors.initials: MA
authors.lastname: Al-Shahat
authors.forename: Reem
authors.initials: R
authors.lastname: El-Gendy
mesh_terms: D000368:Aged; D003758:Dental Implantation, Endosseous / Q000009:adverse effects*; D019094:Dental Prosthesis, Implant-Supported; D019232:Dental Restoration Failure; D003828:Denture, Overlay; D006801:Humans; D008297:Male; D008855:Microscopy, Electron, Scanning; D008875:Middle Aged; D016348:Osseointegration