In-vitro subsurface remineralisation of artificial enamel white spot lesions pre-treated with chitosan

Jing Zhang; Victoria Boyes; Frederic Festy; Richard J M Lynch; Timothy F Watson; Avijit Banerjee

doi:10.1016/j.dental.2018.04.010

In-vitro subsurface remineralisation of artificial enamel white spot lesions pre-treated with chitosan

Dent Mater. 2018 Aug;34(8):1154-1167. doi: 10.1016/j.dental.2018.04.010. Epub 2018 May 8.

Authors

Jing Zhang¹, Victoria Boyes¹, Frederic Festy¹, Richard J M Lynch², Timothy F Watson³, Avijit Banerjee⁴

Affiliations

¹ Tissue Engineering & Biophotonics Research Division, King's College London Dental Institute, King's Health Partners, London, UK.
² Department of Health Services Research and School of Dentistry, University of Liverpool, Liverpool, UK; GlaxoSmithKline Consumer Healthcare, Weybridge, UK.
³ Tissue Engineering & Biophotonics Research Division, King's College London Dental Institute, King's Health Partners, London, UK; Conservative & MI Dentistry, Dental Institute, King's College London Dental Institute, King's Health Partners, London, UK.
⁴ Tissue Engineering & Biophotonics Research Division, King's College London Dental Institute, King's Health Partners, London, UK; Conservative & MI Dentistry, Dental Institute, King's College London Dental Institute, King's Health Partners, London, UK. Electronic address: avijit.banerjee@kcl.ac.uk.

PMID: 29752161
DOI: 10.1016/j.dental.2018.04.010

Abstract

Objective: To test the null hypothesis that chitosan application has no impact on the remineralisation of artificial incipient enamel white spot lesions (WSLs).

Methods: 66 artificial enamel WSLs were assigned to 6 experimental groups (n=11): (1) bioactive glass slurry, (2) bioactive glass containing polyacrylic acid (BG+PAA) slurry, (3) chitosan pre-treated WSLs with BG slurry (CS-BG), (4) chitosan pre-treated WSLs with BG+PAA slurry (CS-BG+PAA), (5) remineralisation solution (RS) and (6) de-ionised water (negative control, NC). Surface and cross-sectional Raman intensity mapping (960cm^-1) were performed on 5 samples/group to assess mineral content. Raman spectroscopy and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) were used to identify the type of newly formed minerals. Surface and cross-sectional Knoop microhardness were implemented to evaluate the mechanical properties after remineralisation. Surface morphologies and Ca/P ratio were observed using scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDX). Data were statistically analysed using one-way ANOVA with Tukey's test.

Results: BG+PAA, CS-BG, RS presented significantly higher mineral regain compared to NC on lesion surfaces, while CS-BG+PAA had higher subsurface mineral content. Newly mineralised crystals consist of type-B hydroxycarbonate apatite. CS-BG+PAA showed the greatest hardness recovery, followed by CS-BG, both significantly higher than other groups. SEM observations showed altered surface morphologies in all experimental groups except NC post-treatment. EDX suggested a higher content of carbon, oxygen and silicon in the precipitations in CS-BG+PAA group. There was no significant difference between each group in terms of Ca/P ratio.

Significance: The null hypothesis was rejected. Chitosan pre-treatment enhanced WSL remineralisation with either BG only or with BG-PAA complexes. A further investigation using dynamic remineralisation/demineralisation system is required with regards to clinical application.

Keywords: Bioglass; Chitosan; Dental caries; Polyacrylic acid; Raman; Remineralization.

MeSH terms

Acrylic Resins / chemistry
Ceramics / chemistry
Chitosan / pharmacology*
Dental Enamel / chemistry
Dental Enamel / drug effects
Hardness
Materials Testing
Microscopy, Electron, Scanning
Spectrometry, X-Ray Emission
Spectroscopy, Fourier Transform Infrared
Spectrum Analysis, Raman
Surface Properties
Tooth Demineralization / drug therapy*
Tooth Remineralization / methods*

Substances

Acrylic Resins
Bioglass
carbopol 940
Chitosan