title: Effect of green tea extract on bonding durability of an etch-and-rinse adhesive system to caries-affected dentin.
abstract: OBJECTIVE
  Green tea extract has been advocated as a matrix metalloproteinase (MMP) inhibitor; however, its effect on bond durability to caries-affected dentin has never been reported. Thus, the aim of this in vitro study was to evaluate the effect of two MMP inhibitors (2% chlorhexidine and 2% green tea extract), applied after acid etching, on bond durability of an etch-and-rinse adhesive system to caries-affected dentin.
  
  
  METHODS
  Occlusal enamel was removed from third molars to expose the dentin surface, and the molars were submitted to a caries induction protocol for 15 days. After removal of infected dentin, specimens were conditioned with 37% phosphoric acid (15 seconds) and randomly divided into three groups, according to the type of dentin pretreatment (n=10): NT: no treatment; GT: 2% green tea extract; CLX: 2% chlorhexidine. The etch-and-rinse adhesive system (Adper™ Single Bond 2, 3M ESPE, St. Paul, MN, USA) was applied according to the manufacturer's instructions, and composite resin restorations were built on the dentin. After 24 hours, at 37°C, the resin-tooth blocks were sectioned perpendicularly to the adhesive interface in the form of sticks (0.8 mm2 of adhesive area) and randomly subdivided into two groups according to when they were to be submitted to microtensile bond strength (μTBS) testing: immediately or 6 months after storage in distilled water. Data were reported in MPa and submitted to two-way ANOVA for completely randomized blocks, followed by Tukey's test (α=0.05).
  
  
  RESULTS
  After 24 hours, there was no significant difference in the μTBS of the groups. After 6 months, the GT group had significantly higher μTBS values.
  
  
  CONCLUSIONS
  It was concluded that the application of 2% green tea extract was able to increase bond durability of the etch-and-rinse system to dentin. Neither the application of chlorhexidine nor non-treatment (NT - control) had any effect on bond strength after water storage.
authors.affiliation: Faculdade de Odontologia e Centro de Pesquisas Odontológicas São Leopoldo Mandic, Campinas, SP, Brasil.
authors.forename: Carolina
authors.initials: C
authors.lastname: Carvalho
authors.affiliation: Faculdade de Odontologia e Centro de Pesquisas Odontológicas São Leopoldo Mandic, Campinas, SP, Brasil.
authors.forename: Fernando Pelegrim
authors.initials: FP
authors.lastname: Fernandes
authors.affiliation: Faculdade de Odontologia e Centro de Pesquisas Odontológicas São Leopoldo Mandic, Campinas, SP, Brasil.
authors.forename: Valeria da Penha
authors.initials: Vda P
authors.lastname: Freitas
authors.affiliation: Faculdade de Odontologia e Centro de Pesquisas Odontológicas São Leopoldo Mandic, Campinas, SP, Brasil.
authors.forename: Fabiana Mantovani Gomes
authors.initials: FM
authors.lastname: França
authors.affiliation: Faculdade de Odontologia e Centro de Pesquisas Odontológicas São Leopoldo Mandic, Campinas, SP, Brasil.
authors.forename: Roberta Tarkany
authors.initials: RT
authors.lastname: Basting
authors.affiliation: Faculdade de Odontologia e Centro de Pesquisas Odontológicas São Leopoldo Mandic, Campinas, SP, Brasil.
authors.forename: Cecilia Pedroso
authors.initials: CP
authors.lastname: Turssi
authors.affiliation: Faculdade de Odontologia e Centro de Pesquisas Odontológicas São Leopoldo Mandic, Campinas, SP, Brasil.
authors.forename: Flávia Lucisano Botelho
authors.initials: FL
authors.lastname: Amaral
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D000704:Analysis of Variance; D000891:Anti-Infective Agents, Local / Q000737:chemistry*; D002710:Chlorhexidine / Q000737:chemistry*; D001840:Dental Bonding / Q000379:methods; D003731:Dental Caries / Q000188:drug therapy*; D003738:Dental Cements / Q000737:chemistry*; D003804:Dentin / Q000187:drug effects*; D017220:Dentin-Bonding Agents / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D010756:Phosphoric Acids / Q000737:chemistry*; D011897:Random Allocation; D015203:Reproducibility of Results; D013499:Surface Properties; D013662:Tea / Q000737:chemistry*; D013718:Tensile Strength; D013997:Time Factors
chemical_list: C554641:Adper single bond 2; D000891:Anti-Infective Agents, Local; D003738:Dental Cements; D017220:Dentin-Bonding Agents; D010756:Phosphoric Acids; D013662:Tea; C030242:phosphoric acid; D002710:Chlorhexidine