Selective demineralisation of dentine extrafibrillar minerals—A potential method to eliminate water-wet bonding in the etch-and-rinse technique

Bingqing Li, Xiaoming Zhu, Lin Ma, Fangping Wang, Xiaoqiang Liu, Xu Yang, Jianfeng Zhou, Jianguo Tan, David Henry Pashley, Franklin Chi Meng Tay

Research output: Contribution to journalArticle

8 Scopus citations


Objective The present study tested the central hypothesis that selective demineralisation of dentine extrafibrillar minerals by lowering the phosphoric acid concentration improves the quality of the resin-dentine interface. Methods Dentine surfaces were etched with different concentrations of phosphoric acid (1, 5, 10, 20, 30 or 40 wt%). Scanning electron microscopy was used to observe the micromorphology of the etched dentine surfaces. Energy dispersive X-ray analysis was performed to determine the residual Ca-content of the demineralised dentine matrix. Atomic force microscopy-based nanoindentation was used to analyse the nanomechanical properties of the treated dentine surfaces. The influence of H3PO4 concentration on resin-dentine bond strength was evaluated by microtensile bond strength testing. One-way ANOVA was used to compare the residual Ca-content ratio, reduced elastic modulus (Er) of the treated dentine surfaces and microtensile bond strength among groups. Results Collagen fibrils appeared to be wider in diameter after etching with 5% and 10% H3PO4. The partially-demineralized collagen scaffold retained part of its rigidity to maintain an uncollapsed three-dimensional structure. Etching with 1% H3PO4 resulted in the highest residual Ca-content ratio and Er of demineralised dentine matrix, followed by 5% H3PO4. Those values were all significantly higher than values derived from the other groups. Etching with 30% H3PO4 resulted in the lowest Ca-content ratio and Er. Using 5% H3PO4 as etchant resulted in the highest resin-dentine bond strength. Conclusions Selective demineralisation of the dentine matrix may be achieved by lowering the H3PO4 concentration to 5 wt%, to achieve better bonding performance. Clinical relevance By retaining intrafibrillar minerals, more through air-drying of the partially demineralised collagen matrix may be accomplished without the need to worry about collapsing a mineral-free collagen matrix during air-drying. This may result in the elimination of water-wet bonding during the application of etch-and-rinse adhesives.

Original languageEnglish (US)
Pages (from-to)55-62
Number of pages8
JournalJournal of Dentistry
StatePublished - Sep 1 2016


  • Collagen matrix
  • Etch-and-rinse
  • Interfibrillar space
  • Intrafibrillar mineral
  • Selective demineralisation

ASJC Scopus subject areas

  • Dentistry(all)

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