title: A retrospective analysis of 125 single molar crowns supported by two implants: long-term follow-up from 3 to 12 years.
abstract: OBJECTIVE
  The purpose of this study was to analyze retrospectively the survival rate of implants used in pairs to support a single molar crown over a long-term follow-up period and to compare the efficacy of this technique to other existing methods of treatment.
  
  
  METHODS
  The charts and radiographs of 105 patients who each received two implants to support a screw-retained single molar were examined according to the following criteria: age, gender, location of implant, time of loading (delayed versus immediate), opposing dentition, and the existence of adjacent implants.
  
  
  RESULTS
  Patients with follow-up between 3 and 12 years were selected to illustrate the long-term outcomes of the two-implant replacement procedure. Two hundred fifty implants were placed in 125 molar sites in 105 patients. Five of the 250 implants failed, resulting in a cumulative survival rate of 98.0%. Seven of 125 restorations experienced porcelain fracture (5.6%), seven prosthetic screws loosened (5.6%), and one abutment screw loosened (< 1.0%).
  
  
  CONCLUSIONS
  The placement of two implants to support a screw-retained single molar successfully reduces rotational forces that create stress on the implant. A single regular-diameter or even a wide-diameter implant is susceptible to these forces, which may lead to fatigue over the long term.
  
  
  CONCLUSIONS
  Two implants for the replacement of a single molar represent an effective method that provides a high survival rate over a long-term follow-up period. This approach produced a cumulative survival rate higher than that usually seen in studies of single implants used for molar replacement. The two implant-supported molar crown showed fewer complications than single implant-supported molar crowns.
authors.affiliation: Pl Dental Center, Institute for Facial Esthetics, Forth Washington, Pennsylvania 19034, USA.
authors.forename: Glenn J
authors.initials: GJ
authors.lastname: Wolfinger
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Balshi
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Wulc
authors.forename: Stephen F
authors.initials: SF
authors.lastname: Balshi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003442:Crowns; D000044:Dental Abutments; D015921:Dental Implants; D003776:Dental Porcelain / Q000737:chemistry; D019094:Dental Prosthesis, Implant-Supported; D019232:Dental Restoration Failure; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D057893:Immediate Dental Implant Loading; D008137:Longitudinal Studies; D008297:Male; D008334:Mandible / Q000601:surgery; D008437:Maxilla / Q000601:surgery; D008875:Middle Aged; D008963:Molar; D012189:Retrospective Studies; D012399:Rotation; D013314:Stress, Mechanical; D016019:Survival Analysis; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D015921:Dental Implants; D003776:Dental Porcelain