The effects of sequential and continuous chelation on dentin

Priti P Rath; Cynthia K Y Yiu; Jukka P Matinlinna; Anil Kishen; Prasanna Neelakantan

doi:10.1016/j.dental.2020.10.010

The effects of sequential and continuous chelation on dentin

Dent Mater. 2020 Dec;36(12):1655-1665. doi: 10.1016/j.dental.2020.10.010. Epub 2020 Nov 5.

Authors

Priti P Rath¹, Cynthia K Y Yiu², Jukka P Matinlinna³, Anil Kishen⁴, Prasanna Neelakantan⁵

Affiliations

¹ Discipline of Endodontology, Department of Restorative Dental Sciences, Faculty of Dentistry, The University of Hong Kong, Hong Kong Special Administrative Region.
² Discipline of Pediatric Dentistry, Department of Pediatric Dentistry and Orthodontics, Faculty of Dentistry, The University of Hong Kong, Hong Kong Special Administrative Region.
³ Dental Materials Science, Department of Applied Oral Sciences and Community Dental Care, Faculty of Dentistry, The University of Hong Kong, Hong Kong Special Administrative Region.
⁴ Faculty of Dentistry, The University of Toronto, Dentistry; Mount Sinai Hospital, Toronto, ON, Canada.
⁵ Discipline of Endodontology, Department of Restorative Dental Sciences, Faculty of Dentistry, The University of Hong Kong, Hong Kong Special Administrative Region. Electronic address: prasanna@hku.hk.

PMID: 33162115
DOI: 10.1016/j.dental.2020.10.010

Abstract

Objective: Proteolytic and demineralizing agents have a profound influence on the dentin ultrastructure, which plays a key role in the mechanical integrity of the tooth and integrity of dentin-biomaterial interfaces. In-depth characterization of dentin treated with a novel root canal irrigation protocol comprising sodium hypochlorite (NaOCl) and etidronate (HEDP) is lacking. This study comprehensively characterized and compared the effects of the continuous chelation (NaOCl/HEDP) and sequential chelation (NaOCl/EDTA) protocols on dentin.

Methods: Dentin blocks, dentin powder and root canals of mandibular premolars were distributed into Group 1, Saline (control); Group 2, NaOCl/EDTA; and Group 3, NaOCl/HEDP. Ultrastructural characteristics of the treated dentin were investigated using electron microscopy and light microscopy, while the surface roughness was analyzed using atomic force microscopy. Chemical compositional changes were characterized using Fourier transform infrared spectroscopy (FTIR) and energy-dispersive-X-ray spectroscopy (EDS), while collagen degradation was determined using ninhydrin assay. Data were statistically analyzed using multiple-factor one-way ANOVA and Tukey HSD tests (P = 0.05).

Results: NaOCl/HEDP resulted in partially degraded, yet mineralized collagen fibers, with minimal alteration to the subsurface matrix. Conversely, NaOCl/EDTA dissolved the hydroxyapaptite encapsulation, exposing collagen fibre bundles. There was no significant difference in the surface roughness between the two protocols (P > 0.05). NaOCl/HEDP resulted in homogenous distribution of organic and inorganic components on the treated surface.

Significance: This study highlighted that continuous chelation (NaOCl/HEDP) resulted in a frail surface collagen layer while sequential chelation (NaOCl/EDTA) exposed bare collagen fibres. These surface and sub-surface effects potentially contribute to structural failures of dentin and/or dentin-biomaterial interfacial failures.

Keywords: Collagen; Dentin; Ethylene diamine tetraacetic acid; Etidronic acid; Sodium hypochlorite.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Dental Pulp Cavity
Dentin*
Edetic Acid
Root Canal Irrigants*
Root Canal Therapy
Sodium Hypochlorite

Substances

Root Canal Irrigants
Edetic Acid
Sodium Hypochlorite