title: [The ultrastructural study of bonding interface between two adhesive systems and three types of dental hard tissue].
abstract: OBJECTIVE
  To compare of the morphological ultrastructure of the 7th generation self-etching adhesive Adper Easy One and two-step total etch adhesive Adper Singlebond 2 after being bonded with the composite resin.
  
  
  METHODS
  Buccal and lingual box-like holes were made in 20 isolated human molars (5mm in diameter, 3mm in depth), and cuted to pieces from surface of middle part of root (5mm in length, 3mm in width). They were equally divided into 2 groups with 10 root slices and 10 crowns each. The cavities of crown and root pieces were respectively bonded with adhesives of Adper Singlebond 2 and Adper Easy One, and were vertically cuted open from the midline after filling with composite resin to get 20 specimens in each group. Ten specimens of root and crown were randomly selected from each group for 5000 times of thermocycling, and the remaining specimens were soaked in distilled water at room temperature for 1 month. Then all the specimens were polished with sand paper, fixed dehydrated, vacuum dried and sprayed, and the bonding interfaces of the filling edge of profile were scanned by scanning electron microscope(SEM).
  
  
  RESULTS
  SEM photos showed that in the group of total etching Adper Singlebond 2 bonding placed at room temperature, the enamel, cementum and the resin bonded closely with the adhesive after thermocycling. In the group of self etching Adper Easy One bonding placed at room temperature, the adhesive bonded to the enamel, small cracks were occasionally seen, and resin penetration blend within the resin in dentinal tubules, and enamel bonded well to the cementum. The specimens after thermocycling bonded enamel loosely with distinct cracks,while the dentinal tubules and resin penetration integrated and cementum bonded well to the dentin.
  
  
  CONCLUSIONS
  Ultra-micro structure observation by SEM shows that Adper Singlebond 2 total etch adhesive has better bonding to enamel than the self-etching adhesive Adper Easy One, but the bonding to dentin and cementum has no significant difference.
authors.affiliation: Department of Operative Dentistry and Endodontics,College of Stomatology, Fourth Military Medical University.Xi'an 710032, Shanxi Province, China. qichunzi@hotmail.com
authors.forename: Chun-zi
authors.initials: CZ
authors.lastname: Qi
authors.forename: Yong
authors.initials: Y
authors.lastname: Jiang
authors.forename: Shi-yang
authors.initials: SY
authors.lastname: Li
authors.forename: Yuan
authors.initials: Y
authors.lastname: Lin
authors.forename: Xiao-min
authors.initials: XM
authors.lastname: Fan
authors.forename: Qing
authors.initials: Q
authors.lastname: Yu
mesh_terms: D000134:Acid Etching, Dental; D000269:Adhesives; D003188:Composite Resins; D001840:Dental Bonding; D003743:Dental Enamel; D003804:Dentin; D017220:Dentin-Bonding Agents; D006801:Humans; D008963:Molar; D019279:Resin Cements; D019228:Tooth Crown
chemical_list: D000269:Adhesives; D003188:Composite Resins; D017220:Dentin-Bonding Agents; D019279:Resin Cements