title: [Effect of different molarity cathepsins specific inhibitor E-64 on dentin-resin bonding durability].
abstract: OBJECTIVE
  To investigate, in vitro, the effect of cathepsins specific inhibitor N-(trans-epoxysuccinyl)-L-leucine 4-guanidinobutylamide(E-64) on dental endogenous cathepsins and to find its most effective molarity to elevate dentin-resin bonding durability.
  
  
  METHODS
  Fifty recently extracted human third molars were divided into five groups according to random number table, and treated with different molarity of E-64 as follow: 0, 2.5, 5.0, 10.0 and 20.0 µmol/L. The group 0 µmol/L was control group. Then 20 specimens of dentin-resin composite were fabricated in each group. Half of the specimens were tested after 24 h water storage(37 °C) and the other half were tested after 90 days water storage(37 °C) followed by 3000 cycles'thermocyling(5-55 °C) as aging treatment. Fractured specimens were analyzed using scanning electron microscopy(SEM).
  
  
  RESULTS
  After 24 h water storage, no significant differences were found in micro-tensile bond strength(µTBS) of samples between different groups (P > 0.05). However, after ageing treatment, µTBS of the samples in group 2.5, 5.0, 10.0 and 20.0 µmol/L [(18.7 ± 2.7), (20.8 ± 3.4), (18.3 ± 2.8) and (19.1 ± 2.7) MPa] were significantly higher than that in group 0 µmol/L [(15.1 ± 3.0) MPa] (P < 0.05). Only in the group 5.0 µmol/L no significant difference was found between the original and the decreased value of µTBS(P > 0.05), while the µTBS in other groups decreased significantly after aging treatment(P < 0.05). Failure types were almost adhesive and mixed types. Collagens in hybrid layer were less degraded in the groups using E-64 after aging treatment than control group.
  
  
  CONCLUSIONS
  E-64 was effective on inhibiting cathepsins activity in dentin, and induced less collagens degradation in smear layer for better dentin-resin bond durability.
authors.affiliation: Department of Prosthodontics, Guanghua School of Stomatology, Hospital of Stomatology, Sun Yat-sen University & Guangdong Provincial Key Laboratory of Stomatology, Guangzhou 510055, China.
authors.forename: Wei-xiang
authors.initials: WX
authors.lastname: Yang
authors.forename: Wen-hao
authors.initials: WH
authors.lastname: Zhang
authors.forename: Shu-yi
authors.initials: SY
authors.lastname: Wu
authors.forename: Ke
authors.initials: K
authors.lastname: Yao
authors.forename: Guo-bin
authors.initials: GB
authors.lastname: Liang
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
mesh_terms: D000293:Adolescent; D000328:Adult; D002403:Cathepsins / Q000037:antagonists & inhibitors*; D003094:Collagen / Q000378:metabolism; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding; D003799:Dental Stress Analysis; D003804:Dentin / Q000648:ultrastructure*; D017220:Dentin-Bonding Agents / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007930:Leucine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology; D008855:Microscopy, Electron, Scanning; D008964:Molar, Third; D011897:Random Allocation; D013718:Tensile Strength; D055815:Young Adult
chemical_list: D003188:Composite Resins; D017220:Dentin-Bonding Agents; D003094:Collagen; D002403:Cathepsins; D007930:Leucine; C024974:E 64