title: Reliability of retrievable cemented implant-supported prostheses.
abstract: BACKGROUND
  One of the disadvantages of a cemented implant restoration is the potential difficulty of retrieving it. The restoration may be destroyed during removal.
  
  
  OBJECTIVE
  The purpose of this retrospective clinical study was to assess the long-term survival rates of cemented posterior metal ceramic implant-supported prostheses (ISPs) with a metal screw access hole.
  
  
  METHODS
  During a 12-year period, 274 cemented ISPs with an abutment screw access hole in the metal framework were assessed and served as the study group, and 119 conventional cemented ISPs (without access hole) served as the control group. Participants were followed every 6 months in the first year and once a year subsequently. Ceramic fracture, screw loosening, and refabrication were the prosthetic outcome parameters evaluated at the recall. The Pearson Chi square and Fisher exact test were used to compare the outcome parameters between the control and study groups.
  
  
  RESULTS
  A total of 1005 implants and 393 ISPs were evaluated. Ceramic fracture occurred in 6.6% of the ISPs (6.2% test and 7.6% control). Screw loosening occurred in 3.28% of the test group and 3.36% of the control group. Refabrication of ISPs was done in 2.79% of all restorations, (1.45% test and 6.72% control [P=.012]).
  
  
  CONCLUSIONS
  Within the limits of this study, preparing cemented ISPs with a screw access hole in the metal framework improves ISP survival rates over time and lowers the cost of maintenance without increasing the risk for porcelain fracture or screw loosening.
authors.affiliation: Associate Professor, Department of Oral Rehabilitation, School of Dental Medicine, Tel Aviv University, Tel Aviv, Israel. Electronic address: nissandr@gmail.com.
authors.forename: Joseph
authors.initials: J
authors.lastname: Nissan
authors.affiliation: Instructor, Department of Oral Rehabilitation, School of Dental Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: David
authors.initials: D
authors.lastname: Snir
authors.affiliation: Instructor, Department of Oral Rehabilitation, School of Dental Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Ofir
authors.initials: O
authors.lastname: Rosner
authors.affiliation: Lecturer, Department of Periodontology, School of Dental Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Roni
authors.initials: R
authors.lastname: Kolerman
authors.affiliation: Resident, Department of Periodontology, School of Dental Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Liat
authors.initials: L
authors.lastname: Chaushu
authors.affiliation: Associate Professor, Oral & Maxillofacial Surgery, The Maurice and Gabriela Goldschleger School of Dental Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Gavriel
authors.initials: G
authors.lastname: Chaushu
mesh_terms: D000328:Adult; D000368:Aged; D003738:Dental Cements / Q000627:therapeutic use*; D017268:Dental Prosthesis Retention / Q000379:methods; D019094:Dental Prosthesis, Implant-Supported / Q000379:methods; D019232:Dental Restoration Failure; D020878:Device Removal / Q000009:adverse effects / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D003738:Dental Cements