title: A 4-year retrospective clinical study of Class I and Class II composite restorations.
abstract: OBJECTIVE
  The purpose of this study was to determine the longevity and quality of Class I and Class II resin composite (Herculite XR) restorations placed in private practice.
  
  
  METHODS
  One thousand two hundred and nine Class I and Class II composite restorations with margins in enamel were evaluated clinically after periods of between 12 months and 4.5 years in clinical service by two calibrated examiners using a modified version of established criteria.
  
  
  RESULTS
  Of the restorations investigated 94.8% were rated as 'good' (Alpha 79.3%) or 'clinically acceptable' (Bravo 15.5%). Significantly more restorations in premolar teeth were rated as Alpha (82%) than in permanent molar teeth (77%). The survival rate after 4 years was around 87%. The 50% survival-time, calculated by extrapolation according to Weibull, was approximately 9 years.
  
  
  CONCLUSIONS
  It is concluded that the composite investigated is an appropriate material for the restoration of Class I and Class II lesions with margins located in enamel in premolar and permanent molar teeth.
authors.affiliation: Department of Conservative Dentistry and Periodontology, Medical University Hannover, Germany.
authors.forename: W
authors.initials: W
authors.lastname: Geurtsen
authors.forename: U
authors.initials: U
authors.lastname: Schoeler
mesh_terms: D001641:Bicuspid; D003188:Composite Resins; D003743:Dental Enamel; D018772:Dental Marginal Adaptation; D019232:Dental Restoration Failure; D003793:Dental Restoration, Permanent / Q000145:classification* / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008963:Molar; D019279:Resin Cements; D012189:Retrospective Studies; D013499:Surface Properties; D013997:Time Factors
chemical_list: D003188:Composite Resins; D019279:Resin Cements; C065770:Herculite XR