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Title: 0222 - Protection and Acid Resistivity of Bioactive-Glasses, Arginine and Calcium Silicate

Authors:

Behrad Mahmoodi (Presenter)
University of Southampton

Robert Wood, University of Southampton
Richard Cook, University of Southampton

Abstract:

Objectives: The purpose of this study was to evaluate the acid resistivity, tribological protection and remineralisation offered by five toothpastes containing Calcium-Sodium-Phosphosilicate (Novamin®), Chloro-Calcium-Phospho-Silicate (BioMinC®), Fluoro-Calcium-Phospho-Silicate (BioMinF®), Arginine (Pro-Argin®), and Calcium Silicate (Regenerate®) using nanomechanical characterisation in a hydrated state and Raman microscopy.

Methods: 50 Bovine dentine discs were divided into 5 toothpaste groups. Discs were brushed twice daily for two minutes over 7 days and stored in artificial saliva after every brushing cycle. Scanning electron microscopy was used to demonstrate layer formation after 7 days of simulated brushing. 20 indents were performed on each disc pre and post brushing using a 5μm radius spherical diamond to a maximum load of 10mN. 5 discs were chosen at random from each group for the citric acid challenge. Dentin discs were immersed into 15ml of 1 wt% citric acid (pH 3.2) for 2 minutes. Nanoindentation were repeated after the acid challenge to evaluate the resistance of the hydroxyapatite like layers. The other 5 discs were initially characterised by Raman spectroscopy followed by multi-pass wear test using the above tip and 300mN load.

Results: After brushing the layers formed by all 5 toothpaste significantly increased the hardness and modulus (p<0.05). Regenerate® produced the hardest layer followed by Pro-Argin®. The layer deposited on dentine by Pro-Argin® was significantly more acid resistant than the layers formed by other 4 toothpastes. There was no significant difference between the hadness, modulus and acid resistivity of layers formed by Novamin®, BioMinC®, BioMinF®, Raman measurements showed increase in phosphate intensity after brushing. The increase in intensities followed the same trend as mechanical properties.

Conclusions: Although Regenerate toothpaste produced the hardest layer after brushing it did not perform well under acid challenge. The layer formed by Pro-Argin® had the highest hardness and demonstrated the best acid resistance out of the five pastes, and may offer the best protection to the dental tissue.

Table(s):

Hardness/GPa Regenerate® Pro-Argin®
Novamin®
BioMinC®
BioMinF®
Baseline 0.58
0.52 0.55 0.57 0.53
After brushing (7 days) 0.83
0.78 0.75 0.75 0.72
After acid Challange 0.57 0.71 0.66 0.65 0.58

This abstract is based on research that was funded entirely or partially by an outside source:
EPSRC

Disclosure Statement:
The submitter must disclose the names of the organizations with which any author have a relationship, the nature of the relationship, and the clinical or research area involved. The following is submitted: NONE

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