Effectiveness of iontophoresis in enhancing remineralisation of carious lesions

Abstract

People are increasingly looking toward healthy ageing, and oral health is becoming an important universal issue. Tooth loss has been identified as an extremely important factor among the oral health-related issues affecting the elderly’s quality of life (1). It has been reported that around 50% of those who are aged 75 or over have root caries, therefore putting them at a high risk of tooth loss (2). As the new older generation retain more teeth, root caries has increased due to the presence of systemic and local factors, such as gingival recession, bone loss, dentures, disability, diet, insufficient oral hygiene and dry mouth caused by medications. Development in restoring dental decay and minimally invasive techniques for caries management have been widely studied and examined. These methods are showing good results in the enamel, which is mostly made up of inorganic material and is in continuous contact with the saliva in the oral cavity, which is rich in minerals. However, other parts of the tooth are associated with challenges for remineralisation, like root dentine, which is made up of more organic materials, leading to difficulty in treatment and maintenance. Non-invasive treatment options are commercially available for use as a remineralisation agent for both enamel and dentine.

Alternatively, some novel applications have been developed to improve the efficiency of the remineralisation process. Iontophoresis technology is not a new method in the medical field; it is commonly used in dermatology to push the medication inside skin tissues. The same concept has been transferred to be used in dental treatment with more focus on enamel, but very few studies have been performed on dentine, particularly dentine that is exposed at the tooth surface on the root of the tooth rather than beneath enamel. This research compares the conventional remineralisation methods with iontophoresis technology, using microhardness measurement (Vickers hardness test), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The research presents the outcomes of a variety of different remineralisation regimes to scrutinise the relationship between typical root caries treatments and using iontophoresis technology.

Root dentine surfaces on recently extracted human third molar teeth that were free of enamel and dentine caries lesions were subjected to a sodium acetate buffer at pH4 to produce standard demineralised lesions. After completing the demineralisation process, a series of measurements were taken to validate the demineralisation method. Specimens were embedded and sectioned perpendicular to the tooth longitudinal axis in the middle of the lesion. One half of the tooth was used in the microhardness test, and the second half of the tooth with a lesion was used for scanning electron microscope (SEM) imaging and ED X-ray analysis. It was found that the demineralisation technique was able to create artificial caries in the root dentine. Remineralisation methods were applied to five demineralised teeth in each group of the remineralisation regime. The remineralisation regimes were: calcium chloride (CaCl₂) and phosphate biphosphate (K2HPO4) without polyacrylic acid; calcium chloride (CaCl₂) and phosphate biphosphate (K2HPO4) with polyacrylic acid; GC Tooth Mousse (CPP-ACP); and GC Tooth Mousse Plus (CPP-ACP with fluoride) as conventional remineralisation and using iontophoresis technology (EAER).

The findings of the analysis of this study demonstrate remineralisation achievements among all the different groups. However, these data also suggest that there are no significant differences between using the conventional remineralisation methods and using iontophoresis technology for remineralising root dentine.