title: Effect of centripetal and incremental methods in Class II composite resin restorations on gingival microleakage.
abstract: OBJECTIVE
  The aim of this study was to evaluate the microleakage at gingival margins below the cementoenamel junction (CEJ) of Class II composite restorations using various placement techniques.
  
  
  METHODS
  Sound human maxillary premolars were selected. Eighty slot-style cavities on the mesial or distal surfaces were prepared with the cervical margins located apical to the CEJ. The specimens were divided into two groups based on the restorative technique utilized (centripetal or incremental). Each group was then categorized into two subgroups according to the type of matrix used resulting in a total of four experimental groups as follows: IP=Incremental and Palodent matrix, IT = Incremental and Transparent matrix, CP= Centripetal and Palodent matrix, and CT = Centripetal and Transparent matrix. Following restoration with a total etch adhesive (Single Bond) and a resin composite (Z100), the teeth were thermocycled. Then specimens were immersed in 0.5% basic fuchsin dye for 24 hours at a temperature of 37 degrees C. Sectioned restorations were examined under a stereomicroscope (40X magnification), and the extent of the microleakage was scored and recorded. Data were analyzed using the Kruskal-Wallis non-parametric statistical test (P=0.05).
  
  
  RESULTS
  In the four groups of the study no significant differences in the mean rank of microleakage were observed (p>0.05).
  
  
  CONCLUSIONS
  When the gingival margin was located on cementum, the kind of matrix and filling technique did not reduce the microleakage.
authors.affiliation: Department of Operative Dentistry, School of Dentistry, Dental Research Center, Mashhad University of Medical Sciences, Mashhad, Iran. dr_marjaneh@yahoo.com
authors.forename: Marjaneh
authors.initials: M
authors.lastname: Ghavamnasiri
authors.forename: Horieh
authors.initials: H
authors.lastname: Moosavi
authors.forename: Najmeh
authors.initials: N
authors.lastname: Tahvildarnejad
mesh_terms: D001641:Bicuspid; D017438:Bisphenol A-Glycidyl Methacrylate; D003188:Composite Resins / Q000008:administration & dosage*; D001840:Dental Bonding; D003737:Dental Cavity Preparation; D003763:Dental Leakage / Q000517:prevention & control*; D003793:Dental Restoration, Permanent / Q000295:instrumentation / Q000379:methods*; D017220:Dentin-Bonding Agents; D006801:Humans; D008434:Matrix Bands; D019279:Resin Cements; D012822:Silicon Dioxide / Q000008:administration & dosage; D018709:Statistics, Nonparametric; D019237:Tooth Cervix; D015040:Zirconium / Q000008:administration & dosage
chemical_list: D003188:Composite Resins; D017220:Dentin-Bonding Agents; D019279:Resin Cements; C083568:Z100 composite resin; C115612:single bond; D017438:Bisphenol A-Glycidyl Methacrylate; D012822:Silicon Dioxide; D015040:Zirconium