title: Microleakage of Class II posterior composite restorations with gingival margins placed entirely within dentin.
abstract: OBJECTIVE
  Composite restorations are more frequently being placed with margins apical to the cementoenamel junction. However, margins within dentin are prone to microleakage. The purpose of this in vitro study was to evaluate various restorative procedures in terms of their ability to reduce microleakage in posterior composite restorations with gingival margins within dentin. We also examined the effect of staining time on microleakage.
  
  
  METHODS
  Mesio-occlusal and disto-occlusal preparations were made in 50 extracted molars. Teeth were randomly assigned to receive 1 of 5 treatments followed by restoration with Z100 composite resin: acid etch (control); Clearfil SE Bond; Prompt-L-Pop; Vitrebond/Scotchbond Multipurpose Plus (closed-sandwich technique); or Geristore/Tenure (open-sandwich technique). After 48 hours of water storage followed by sectioning buccolingually, 1 restoration from each tooth was randomly assigned to either 2- or 4-hour immersion in 50% by weight silver nitrate solution. Restorations were removed and gingival floors analyzed to determine the percentage of surface area stained in each of 3 0.5-mm wide zones.
  
  
  RESULTS
  Repeated measures ANOVA did not reveal statistically significant differences in staining for 2 and 4 hours. Compared with the control group, Clearfil SE bond produced statistically significant reductions in leakage in all 3 zones. Prompt-L-Pop did not reduce leakage significantly except in zone 3 (closest to the pulp). Vitrebond and Geristore both reduced microleakage in zones 2 and 3, but the reduction was greater with the use of Vitrebond.
  
  
  CONCLUSIONS
  Both Clearfil SE Bond and Vitrebond in a closed-sandwich technique were effective methods for reducing microleakage within dentin.
authors: Department of Restorative Dentistry, Faculty of Dentistry, University of Manitoba, Winnipeg, Manitoba. stocktn@ms.umanitoba.ca
authors: Lawrence W
authors: LW
authors: Stockton
authors: Susan T
authors: ST
authors: Tsang
mesh_terms: D000704:Analysis of Variance; D003188:Composite Resins / Q000737:chemistry*; D003763:Dental Leakage / Q000175:diagnosis / Q000209:etiology / Q000517:prevention & control*; D018772:Dental Marginal Adaptation; D003793:Dental Restoration, Permanent / Q000009:adverse effects / Q000379:methods*; D003804:Dentin; D017220:Dentin-Bonding Agents; D003936:Diagnosis, Computer-Assisted; D006801:Humans; D008963:Molar; D018709:Statistics, Nonparametric; D013997:Time Factors
chemical_list: D003188:Composite Resins; D017220:Dentin-Bonding Agents