title: Efficacy of four lining materials in sandwich technique to reduce microleakage in class II composite resin restorations.
abstract: OBJECTIVE
  The aim of the present study was to evaluate the effect of four different sandwich techniques on gingival microleakage of Class II direct composite resin restorations.
  
  
  METHODS
  Fifty sound human premolars were selected and randomly divided into five groups (n=10). Class II box only cavities were prepared in one of the proximal surfaces of each tooth with a gingival margin located approximately 0.5 mm below the cemento-enamel junction. Group A (control) was restored incrementally with composite resin (Tetric Ceram). Groups B, C, D, and E were restored with the sandwich technique using a compomer (Compoglass F), flowable composite resin (Tetric Flow), self-cure composite resin (Degufill SC), or resin modified glass ionomer (Fuji II LC), respectively. After thermal-load cycling, the specimens were immersed in 0.5% basic fuschin for 24 hours. Dye penetration (10(-1) mm) was detected using a sectioning technique. Data were analyzed with repeated measurements and Duncan test at α=0.05.
  
  
  RESULTS
  The least amount of microleakage was detected in the incremental group (1.28 ± 0.98). The sandwich technique using resin modified glass ionomer (7.99 ± 9.57) or compomer (4.36 ± 1.78) resulted in significantly more leakage than did the sandwich technique using flowable (1.50 ± 1.97) or self-cure composite (2.26 ± 1.52).
  
  
  CONCLUSIONS
  According to the results of this study, none of the four sandwich technique composite resin restorations used in this study could reduce gingival microleakage to a greater degree than the incremental technique.
authors.forename: S M
authors.initials: SM
authors.lastname: Moazzami
authors.forename: N
authors.initials: N
authors.lastname: Sarabi
authors.forename: H
authors.initials: H
authors.lastname: Hajizadeh
authors.forename: S
authors.initials: S
authors.lastname: Majidinia
authors.forename: Y
authors.initials: Y
authors.lastname: Li
authors.forename: M R
authors.initials: MR
authors.lastname: Meharry
authors.forename: H
authors.initials: H
authors.lastname: Shahrokh
mesh_terms: D000180:Acrylic Resins / Q000627:therapeutic use*; D003188:Composite Resins / Q000627:therapeutic use*; D003731:Dental Caries / Q000601:surgery; D003736:Dental Cavity Lining / Q000379:methods*; D003763:Dental Leakage / Q000517:prevention & control*; D003793:Dental Restoration, Permanent / Q000379:methods*; D005899:Glass Ionomer Cements / Q000627:therapeutic use*; D006801:Humans; D011140:Polyurethanes / Q000627:therapeutic use*; D012117:Resins, Synthetic / Q000627:therapeutic use*
chemical_list: D000180:Acrylic Resins; C105428:Compoglass; C029012:Composite Dental Resin; D003188:Composite Resins; C079765:Fuji II LC cement; D005899:Glass Ionomer Cements; D011140:Polyurethanes; D012117:Resins, Synthetic; C121818:Tetric ceram; C452226:tetric flow composite resin