title: Effect of finishing time and techniques on marginal sealing ability of two composite restorative materials.
abstract: BACKGROUND
  Finishing of composites may adversely influence the sealing ability of direct adhesive restorations.
  
  
  OBJECTIVE
  This study was conducted to determine whether finishing time and techniques under wet or dry conditions affect the microleakage of 2 types of class V composite restorations.
  
  
  METHODS
  Eighty class V preparations were made in the buccal surfaces of noncarious molars with the occlusal margins ending in enamel and the gingival margins in dentin. Dental adhesive (Single Bond) was applied according to the manufacturer's instructions. Half of the preparations were restored with a microfilled composite (Silux Plus) and the other half with a hybrid composite (Filtek Z250). Within each major composite group (n = 40), 4 subgroups (n = 10) were established based on finishing technique (diamond finishing burs or aluminum oxide discs) and finishing time (immediate or delayed by 24 hours). The specimens were stored for 24 hours in 37 degrees C water, thermocycled for 250 cycles between 5 degrees C and 55 degrees C, immersed in 2% methylene blue solution for another 24 hours, and sectioned longitudinally. For both enamel and dentin margins, dye solution penetration at the tooth/composite interface was scored from 0 to 4 under stereoscopy at original magnification x 20. Data were analyzed with the Kruskal-Wallis test (P<.05).
  
  
  RESULTS
  Significantly lower leakage scores were recorded for teeth restored with microfilled composite and finished under wet conditions after 24 hours (P<.01). No significant differences were found among the hybrid composite groups.
  
  
  CONCLUSIONS
  For microfilled composite restorations on dentin margins, delayed wet finishing with diamond burs resulted in significantly lower microleakage scores than all other finishing protocols. Hybrid composite restorations had equivalent levels of microleakage regardless of the finishing method.
authors.affiliation: Faculty of Dentistry, Federal University of Santa Catarina, Florianópolis, Santa Catarina, Brazil. guilherme_lopes@ig.com.br
authors.forename: Guilherme C
authors.initials: GC
authors.lastname: Lopes
authors.forename: Margarete
authors.initials: M
authors.lastname: Franke
authors.forename: Hamilton P
authors.initials: HP
authors.lastname: Maia
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D004396:Coloring Agents; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding; D003737:Dental Cavity Preparation / Q000145:classification; D003743:Dental Enamel / Q000648:ultrastructure; D003763:Dental Leakage / Q000473:pathology; D018772:Dental Marginal Adaptation; D003775:Dental Polishing / Q000295:instrumentation / Q000379:methods*; D003793:Dental Restoration, Permanent / Q000145:classification*; D003804:Dentin / Q000648:ultrastructure; D017220:Dentin-Bonding Agents / Q000737:chemistry; D018130:Diamond / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D008751:Methylene Blue; D008963:Molar; D018709:Statistics, Nonparametric; D013499:Surface Properties; D013696:Temperature; D013816:Thermodynamics; D013997:Time Factors; D014867:Water
chemical_list: D004396:Coloring Agents; D003188:Composite Resins; D017220:Dentin-Bonding Agents; C444701:Filtek Z250; C115612:single bond; D014867:Water; C074741:Silux Plus; D017438:Bisphenol A-Glycidyl Methacrylate; D018130:Diamond; D000537:Aluminum Oxide; D008751:Methylene Blue