title: Sealing capacity of a flowable composite, as a protective base, with different conditioning methods in nonvital bleaching.
abstract: OBJECTIVE
  The purpose of this in vitro study was to determine the microleakage of a nano-flowable composite used as a protective base, applied with different conditioning methods in nonvital bleaching.
  
  
  METHODS
  Forty root-filled teeth were divided into four treatment groups (n = 10 per group): group 1--Er:YAG laser etching + Adper Single Bond 2; group 2-37% phosphoric acid + Adper Single Bond 2; group 3--Adper Prompt L-Pop; and group 4--No treatment. A nano-flowable composite (Filtek Supreme Flow) base was used in each group. For a 24-h period, 40% hydrogen peroxide solution was applied to the pulp chambers, and they were subsequently subjected to a dye (silver nitrate) challenge for 4 h. After the dye was washed out with water, each tooth was cut in half and both halves were exposed to sunlight for 2 h to promote oxidation of the dye, turning it black. Finally the sections were examined under 4x magnification to determine the degree of leakage as assessed with a four-point scale. Statistical analysis was performed with the Mann-Whitney U test.
  
  
  RESULTS
  There were no significant differences between groups 1, 2, and 3 (p > 0.05), but the teeth in group 4 had significantly higher microleakage scores than the teeth in the other groups (p < 0.05).
  
  
  CONCLUSIONS
  Self-etching adhesive application, Er:YAG laser etching, and phosphoric acid etching combined with an adhesive system all showed similar microleakge scores when a nano-flowable composite was applied as a protective base in nonvital bleaching.
authors.affiliation: Department of Conservative Dentistry, School of Dentistry, Baskent University, Bahçelievler-Ankara, Turkey.
authors.forename: Yonca
authors.initials: Y
authors.lastname: Korkmaz
authors.forename: Emel Olga
authors.initials: EO
authors.lastname: Onay
authors.forename: Emre
authors.initials: E
authors.lastname: Ozel
authors.forename: Mete
authors.initials: M
authors.lastname: Ungor
mesh_terms: D000134:Acid Etching, Dental; D003188:Composite Resins / Q000494:pharmacology*; D003763:Dental Leakage; D003764:Dental Materials / Q000494:pharmacology*; D003804:Dentin / Q000187:drug effects; D017220:Dentin-Bonding Agents / Q000494:pharmacology; D006801:Humans; D010895:Pit and Fissure Sealants / Q000494:pharmacology; D014070:Tooth / Q000187:drug effects*; D014073:Tooth Bleaching / Q000379:methods*
chemical_list: D003188:Composite Resins; D003764:Dental Materials; D017220:Dentin-Bonding Agents; D010895:Pit and Fissure Sealants; C111840:flowable hybrid composite