title: Tunnel restorations: a long-term pilot study over a minimum of five years.
abstract: OBJECTIVE
  The purpose of this study was to investigate the long-term performance of tunnel restorations.
  
  
  METHODS
  Thirty-three glass polyalkenoate (ionomer) or cermet restorations were placed in the premolar or first molar teeth of 25 patients. Conservative amalgam control restorations were the means of treatment in 14 similar teeth of the same group. Review as to performance consisted of a regular clinical and radiographic examination and the criteria for failure were recurrent caries, fracture of the marginal ridge or gross loss of restorative material.
  
  
  RESULTS
  After 3 years all types of restoration were satisfactory. By approximately 5 years one-quarter of the glass ionomer and 10% of the cermet restorations had failed. All the failures after any period of service could be replaced by conservative amalgam fillings. None of the controls required replacement.
  
  
  CONCLUSIONS
  While tunnel restorations employing glass ionomer material and the cermet variant do enjoy a degree of success, this preliminary work suggests that small restorations of dental amalgam are more successful in the long term.
authors.affiliation: Conservation Unit, School of Dentistry, Birmingham, UK.
authors.forename: P J
authors.initials: PJ
authors.lastname: Lumley
authors.forename: F J
authors.initials: FJ
authors.lastname: Fisher
mesh_terms: D000328:Adult; D001641:Bicuspid; D016722:Cermet Cements / Q000737:chemistry; D003723:Dental Amalgam / Q000737:chemistry; D003731:Dental Caries / Q000209:etiology; D003793:Dental Restoration, Permanent / Q000379:methods*; D005260:Female; D005899:Glass Ionomer Cements / Q000737:chemistry; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008422:Materials Testing; D008875:Middle Aged; D008963:Molar; D010865:Pilot Projects; D012008:Recurrence; D013499:Surface Properties
chemical_list: D016722:Cermet Cements; D005899:Glass Ionomer Cements; D003723:Dental Amalgam