title: The effects of two cavity preparation methods on the longevity of glass ionomer cement restorations: an evaluation after 12 months.
abstract: BACKGROUND
  The authors undertook a study to evaluate the effect of two cavity preparation methods on the initial survival of two more-viscous glass ionomer cements, or GICs, placed in the occlusal surfaces of permanent molar teeth.
  
  
  METHODS
  Three dentists placed 149 restorations in 68 adult patients in a hospital clinic. They used either atraumatic restorative treatment, or ART, or conventional cavity preparation methods to place two encapsulated esthetic conventional GICs: Fuji IX GP (GC International Corp., Tokyo) and Ketac-Molar Aplicap (3M ESPE, Seefeld, Germany). For comparison, they used high-copper-content GK Amalgam Alloy (Advanced Technology & Materials Co. Ltd., Beijing) in conventional preparations. They evaluated the restorations using both direct and indirect observation methods.
  
  
  RESULTS
  Cavity preparations for which the authors used ART hand instruments took approximately twice as long to complete as did those for which they used conventional rotary instruments. After 12 months, no restorations had failed, but restorations comprising both GICs showed early losses of adjacent sealant material. Both GICs also showed relatively high restoration wear. At 12 months, the mean cumulative net occlusal wear for Fuji IX GP was 77 +/- 47 micrometers, and for Ketac-Molar 83 +/- 51 microm, without statistical significance (P > .05). Color matching improved significantly with time (P < .001), without significant differences in color between the two GICs by 12 months (P = .09). The amalgam alloy had minor surface tarnishing and marginal discrepancies increased with time (P < .00 1).
  
  
  CONCLUSIONS
  All of the occlusal restorations were rated as satisfactory after 12 months. The method of cavity preparation did not affect the restoration performance of the GICs. However, their deterioration requires long-term monitoring. Clinical Implications. The more viscous GICs appear initially suitable for restricted use in clinical practice when placed using either of two cavity preparation methods in the occlusal surfaces of permanent molar teeth in adults.
authors.affiliation: The University of British Columbia, Faculty of Dentistry, Vancouver, Canada.
authors.forename: Kevin H K
authors.initials: KH
authors.lastname: Yip
authors.forename: Roger J
authors.initials: RJ
authors.lastname: Smales
authors.forename: Wei
authors.initials: W
authors.lastname: Gao
authors.forename: Dong
authors.initials: D
authors.lastname: Peng
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D003737:Dental Cavity Preparation / Q000379:methods*; D019554:Dental Restoration Wear; D003793:Dental Restoration, Permanent / Q000295:instrumentation / Q000379:methods*; D005260:Female; D005899:Glass Ionomer Cements; D006801:Humans; D008297:Male; D008963:Molar; D018709:Statistics, Nonparametric
chemical_list: D005899:Glass Ionomer Cements; C424245:Ketac-Molar Aplicap; C110713:fuji IX