title: Effect of hesperidin incorporation into a self-etching primer on durability of dentin bond.
abstract: OBJECTIVE
  Collagen degradation at the resin-dentin interface deteriorates dentin bond durability. The use of natural cross-linkers might offer a positive approach to stabilize the resin-dentin interface. This study evaluated the effects of incorporation of natural cross-linkers into a self-etch adhesive primer on the immediate and long-term micro-tensile bond strengths (μTBS) to dentin.
  
  
  METHODS
  Experimental primers were prepared by incorporating either 0.5%, 1%, 2%, 5% of hesperidin (HPN) or 0.5% of proanthocyanidins (PA) into Clearfil SE primer. Extracted human molar teeth were restored using the experimental primers or the pure SE primer (control). The mechanical properties of the bonded interfaces were measured using the nano-indentation tests. Beam-shaped bonded specimens were sub-divided for one-day and one-year μTBS test. Interfacial collagen morphology was observed using transmission electron microscopy.
  
  
  RESULTS
  The immediate μTBS significantly increased in 0.5%, 1% and 2% HPN-incorporated groups when compared with the control. The mechanical properties of bonded interface were improved with 1% and 2% HPN-incorporated primers. For the long-term μTBS, the 2% and 5% HPN-incorporated group were significantly higher than the control. The morphology of the collagen fibrils were preserved by 5% HPN-incorporation after one-year storage. The PA group, however, failed to improve the μTBS and the mechanical properties of the bonded interfaces.
  
  
  CONCLUSIONS
  The incorporation of 2% HPN into the self-etching primer had a positive effect on the immediate μTBS and mechanical properties of the resin-dentin interfaces. The 5% HPN group preserved the morphology of the collagen in the hybrid layer after one-year storage in artificial saliva.
authors.affiliation: Cariology and Operative Dentistry, Department of Oral Health Science, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan; Global Center of Excellence (GCOE) Program, International Research Center for Molecular Science in Tooth and Bone Diseases at Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, Japan.
authors.forename: Md Sofiqul
authors.initials: MS
authors.lastname: Islam
authors.affiliation: Cariology and Operative Dentistry, Department of Oral Health Science, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan. Electronic address: hiraope@tmd.ac.jp.
authors.forename: Noriko
authors.initials: N
authors.lastname: Hiraishi
authors.affiliation: Cariology and Operative Dentistry, Department of Oral Health Science, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan; Global Center of Excellence (GCOE) Program, International Research Center for Molecular Science in Tooth and Bone Diseases at Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, Japan.
authors.forename: Mohannad
authors.initials: M
authors.lastname: Nassar
authors.affiliation: Paediatric Dentistry and Orthodontics, Faculty of Dentistry, The University of Hong Kong, China.
authors.forename: Cynthia
authors.initials: C
authors.lastname: Yiu
authors.affiliation: Cariology and Operative Dentistry, Department of Oral Health Science, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Otsuki
authors.affiliation: Cariology and Operative Dentistry, Department of Oral Health Science, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan; Global Center of Excellence (GCOE) Program, International Research Center for Molecular Science in Tooth and Bone Diseases at Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, Japan.
authors.forename: Junji
authors.initials: J
authors.lastname: Tagami
mesh_terms: D000134:Acid Etching, Dental; D003804:Dentin / Q000378:metabolism*; D006569:Hesperidin / Q000378:metabolism*; D046529:Microscopy, Electron, Transmission; D013718:Tensile Strength
chemical_list: D006569:Hesperidin
keywords: Collagen; Cross-linker; Elastic modulus; Hardness; Hesperidin; Hybrid layer; Micro-tensile bond strength