Influence of the pulpal components on human dentine permeability in vitro.
OBJECTIVE
To examine the influence of the retained pulpal components on permeability of human dentine by monitoring drug diffusion.


METHODS
Twelve intact dentine discs were prepared from freshly extracted human third molars. The dentine surface on the enamel side was etched with 10% polyacrylic acid for 30 s. The drug diffusion test was carried out before and after removal of the retained pulpal components. Each dentine disc was inserted between two plastic chambers; enamel- and pulpal-side chambers, which were filled with 0.05 mol L(-1) naproxen sodium (NA) and phosphate-buffered saline (PBS), respectively. After 10 min, the solution on the pulpal-side chamber was collected to determine the concentration of NA using a spectrophotometer. To remove the retained pulpal components and residual NA, the pulp chamber of each disc was washed out with PBS and placed in an ultrasonic cleaner. After removal of these components and the residual NA, the drug diffusion test was repeated. The inner surface of the pulp chamber was observed using scanning electron microscopy (SEM) before and after the removal of the retained pulpal components.


RESULTS
The amount of NA that diffused through dentine into the pulp was significantly higher after the pulp chamber was washed out with PBS (paired t-test, P < 0.05). SEM observation demonstrated the presence of the retained pulpal components, odontoblastic layer and some parts of subodontoblastic zone, covering the surface of predentine. These components were removed after the pulp chamber was washed out with PBS followed by cleaning in an ultrasonic cleaner.


CONCLUSIONS
The presence of retained pulpal components had a significant influence on drug diffusion through dentine discs.
Puapichartdumrong
P
P
Pulp Biology and Endodontics, Department of Restorative Sciences, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan.
Ikeda
H
H
Suda
H
H
D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000493:pharmacokinetics* / Q000627:therapeutic use; D003782:Dental Pulp; D003804:Dentin / Q000378:metabolism / Q000648:ultrastructure; D003806:Dentin Permeability; D004058:Diffusion; D006801:Humans; D008855:Microscopy, Electron, Scanning; D008963:Molar; D009288:Naproxen / Q000493:pharmacokinetics* / Q000627:therapeutic use; D009804:Odontoblasts; D011671:Pulpitis / Q000188:drug therapy
D000894:Anti-Inflammatory Agents, Non-Steroidal; D009288:Naproxen