Ultrastructure of smear layer-covered intraradicular dentin after irrigation with BioPure MTAD

Franklin R. Tay, David H. Pashley, Robert J. Loushine, Michael D. Doyle, W. Trent Gillespie, R. Norman Weller, Nigel M. King

Research output: Contribution to journalArticle

36 Scopus citations


The structure of mechanically instrumented intraradicular dentin after irrigation with NaOCl as the initial rinse and BioPure MTAD as the final rinse were examined from the coronal, middle, and apical parts of root canal walls using transmission electron microscopy. Sterile distilled water and EDTA as final rinses were employed as the respective positive and negative controls under the same experimental conditions. There were 2 to 5 μm thick smear layers produced on mechanically instrumented root canal walls that were completely removed by EDTA and BioPure MTAD under agitation. Both irrigants created a zone of demineralized collagen matrices in eroded dentin and around the dentinal tubules, with the mildly acidic BioPure MTAD being more aggressive than EDTA. These demineralized dentin zones create the opportunity for dentin hybridization by infiltration of hydrophilic adhesives/sealers. However, the potential consequences of compaction of hydrophobic sealers against air-dried, collapsed collagen matrices, and hydrolytic degradation of incompletely infiltrated matrices remain unresolved.

Original languageEnglish (US)
Pages (from-to)218-221
Number of pages4
JournalJournal of endodontics
Issue number3
Publication statusPublished - Mar 1 2006



  • EDTA
  • Endodontic smear layer
  • Intraradicular dentin hybridization
  • MTAD
  • NaOCl

ASJC Scopus subject areas

  • Dentistry(all)

Cite this

Tay, F. R., Pashley, D. H., Loushine, R. J., Doyle, M. D., Gillespie, W. T., Weller, R. N., & King, N. M. (2006). Ultrastructure of smear layer-covered intraradicular dentin after irrigation with BioPure MTAD. Journal of endodontics, 32(3), 218-221. https://doi.org/10.1016/j.joen.2005.10.035