title: Effect of various surface protections on the margin microleakage of resin-modified glass ionomer cements.
abstract: BACKGROUND
  Because conventional glass ionomer cements are moisture sensitive, a surface coating is recommended during the initial setting stage. It is unknown whether resin-modified glass ionomer cements also need surface protection.
  
  
  OBJECTIVE
  This study investigated the effect of various surface protections on microleakage with Class V resin-modified glass ionomer restorations.
  
  
  METHODS
  Forty extracted molars with buccal and lingual Class V cavity preparations were restored with a resin-modified glass ionomer (Fuji II LC). The occlusal margin of each restoration was on enamel and the cervical margin on dentin. After immediate finishing and polishing, the teeth were divided into 4 groups according to the following surface protection treatments: group I, unprotected; group II, Fuji varnish; group III, resin adhesive; and group IV, acid etching and resin adhesive. After these procedures, all teeth were stored in isotonic saline for 24 hours, thermocycled 1500 times at 5 degrees C to 60 degrees C, and soaked in dye solution for 24 hours. The teeth then were longitudinally sectioned and observed under a stereomicroscope. The degree of dye penetration was recorded and analyzed with the Kruskal-Wallis and Mann-Whitney tests (P<.05)
  
  
  RESULTS
  None of the 4 groups demonstrated complete margin sealing at either the occlusal or cervical margins. Groups II and III displayed the least microleakage at cervical margins; a significant difference existed between groups I and III (P=.034). Compared with the other 3 groups, group IV showed significantly greater microleakage at the cervical margins.
  
  
  CONCLUSIONS
  Although resin-modified glass ionomers can be finished immediately, they remain moisture sensitive. Within the limitations of this study, the results suggest that resin adhesive should be used as a surface protection to reduce margin microleakage of resin-modified glass ionomer restorations.
authors.affiliation: Department of Operative Dentistry, National Cheng Kung University Hospital, Tainan City, Taiwan. lfen@mail.ncku.edu.tw
authors.forename: S F
authors.initials: SF
authors.lastname: Chuang
authors.forename: Y T
authors.initials: YT
authors.lastname: Jin
authors.forename: P F
authors.initials: PF
authors.lastname: Tsai
authors.forename: T Y
authors.initials: TY
authors.lastname: Wong
mesh_terms: D000134:Acid Etching, Dental; D000180:Acrylic Resins / Q000737:chemistry; D004396:Coloring Agents; D003737:Dental Cavity Preparation / Q000145:classification; D003743:Dental Enamel / Q000648:ultrastructure; D003763:Dental Leakage / Q000145:classification*; D018772:Dental Marginal Adaptation; D003775:Dental Polishing; D003793:Dental Restoration, Permanent / Q000145:classification; D003804:Dentin / Q000648:ultrastructure; D017220:Dentin-Bonding Agents / Q000737:chemistry; D005899:Glass Ionomer Cements / Q000737:chemistry*; D006801:Humans; D007552:Isotonic Solutions; D008422:Materials Testing; D010150:Paint; D019279:Resin Cements / Q000737:chemistry*; D012117:Resins, Synthetic / Q000737:chemistry; D012965:Sodium Chloride; D018709:Statistics, Nonparametric; D013499:Surface Properties; D013816:Thermodynamics
chemical_list: D000180:Acrylic Resins; D004396:Coloring Agents; D017220:Dentin-Bonding Agents; C079765:Fuji II LC cement; D005899:Glass Ionomer Cements; D007552:Isotonic Solutions; D019279:Resin Cements; D012117:Resins, Synthetic; C084018:Scotchbond Multi-Purpose; D012965:Sodium Chloride; C006903:carbopol 940