title: Repair of amalgam restorations with composite resin and bonded amalgam: a microleakage study.
abstract: BACKGROUND
  Total replacement is the most common technique for defective amalgam restorations, and it represents a major part of restorative dental treatment. Repair is an alternative option for amalgam restorations with localized defects.
  
  
  OBJECTIVE
  This study compared microleakage of amalgam restorations repaired by bonded amalgam or composite resin.
  
  
  METHODS
  Thirty extracted human pre-molars were prepared and restored with class I amalgam. A simulated defect was prepared that included the cavosurface margin on restorations, and the pre-molars were assigned to two treatment groups (n=15): In group 1, premolars were treated by composite resin (34% Tooth Conditioner Gel + Adper Single Bond 2 + Z100) and in group 2, premolars were repaired by bonded amalgam (34% Tooth Conditioner Gel + Prime and Bond 2.1 + Permite C). The teeth were immersed in a 50% silver nitrate solution, thermocycled, sectioned longitudinally and then observed by three examiners using a stereomicroscope. Microleakage was evaluated using a 0-4 scale for dye penetration, and data was analyzed by Kruskal Wallis and Dunn tests.
  
  
  RESULTS
  Neither of the two methods eliminated microleakage completely. Composite resin was significantly the most effective for repair/tooth interface sealing (score 0 = 80.0%; P=0.0317). For the repair/restoration interface, composite resin was also statistically more effective as a sealant (score 0=66%; P=0.0005) when compared to the bonded amalgam technique (score 0=13%; P=0.0005).
  
  
  CONCLUSIONS
  The use of adhesive systems significantly affected the ability to seal the repair/ tooth interface. However, at the level of the repair/restoration interface, the bonded amalgam technique may increase microleakage.
authors.affiliation: College of Dentistry, Federal University of Minas Gerais, Belo Horizonte, Brazil. danielavelloso@yahoo.com.br
authors.forename: Daniela Araújo Veloso
authors.initials: DA
authors.lastname: Popoff
authors.forename: Fabiana Santos
authors.initials: FS
authors.lastname: Gonçalves
authors.forename: Cláudia Silami
authors.initials: CS
authors.lastname: Magalhães
authors.forename: Allyson Nogueira
authors.initials: AN
authors.lastname: Moreira
authors.forename: Raquel Conceição
authors.initials: RC
authors.lastname: Ferreira
authors.forename: Ivar A
authors.initials: IA
authors.lastname: Mjör
mesh_terms: D000096:Acetone / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry*; D003300:Copper / Q000737:chemistry; D003723:Dental Amalgam / Q000737:chemistry*; D001840:Dental Bonding / Q000379:methods*; D003737:Dental Cavity Preparation / Q000145:classification; D003738:Dental Cements / Q000737:chemistry; D045662:Dental Etching / Q000379:methods; D003763:Dental Leakage / Q000145:classification*; D003764:Dental Materials / Q000737:chemistry*; D058250:Dental Restoration Repair; D006801:Humans; D008422:Materials Testing; D011109:Polymethacrylic Acids / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D012834:Silver / Q000737:chemistry; D016622:Silver Staining; D013696:Temperature; D013997:Time Factors; D015040:Zirconium / Q000737:chemistry
chemical_list: C554641:Adper single bond 2; D003188:Composite Resins; D003738:Dental Cements; D003764:Dental Materials; D011109:Polymethacrylic Acids; C083568:Z100 composite resin; C444444:prime and bond 2.1; D000096:Acetone; D012834:Silver; D012822:Silicon Dioxide; D003300:Copper; D003723:Dental Amalgam; C092423:Permite C; D015040:Zirconium