Preventive effects of iontophoresis on bovine enamel decalcification through enhancing uptake and transportation of fluoride - in vitro study

The dual anti-caries effect of carboxymethyl chitosan nanogel loaded with chimeric lysin ClyR and amorphous calcium phosphate

In this study, we evaluated the anti-biofilm and anti-demineralization abilities of a novel material, CMC-ClyR-ACP nanogel, designed by loading the chimeric lysin ClyR and amorphous calcium phosphate (ACP) into a nanocarrier material carboxymethyl chitosan (CMC), in a demineralization model. Dynamic light scattering, transmission electron microscopy, and Fourier transmission infrared spectroscopy showed that CMC-ClyR-ACP nanogel was synthesized successfully. Enamel samples prepared from premolars were divided into five groups according to their treatments with: (i) double distilled water ddH₂ O, (ii) CMC-ACP, (iii) CMC-ClyR-ACP, (iv) ClyR, or (v) 0.12% chlorhexidine. Streptococcus mutans was allowed to form biofilms on the teeth for two days before treatment procedures were carried out from day 3 to day 6. The relative biofilm viability analyzed by Cell Counting Kit-8 showed that it was significantly lower (at 55.7%) for CMC-ClyR-ACP than seen for ddH₂ O (89.9%), which was consistent with result of confocal laser scanning microscopy. The percentage surface hardness loss of CMC-ClyR-ACP (29.2%) was significantly lower than that of CMC-ACP (51.0%) and ClyR (58.7%) alone, and there was no significant difference between CMC-ClyR-ACP and chlorhexidine (26.9%), which was confirmed by scanning electron microscopy. Therefore, CMC-ClyR-ACP nanogel may be an effective strategy for the control of enamel demineralization.

Selected Medicines Used in Iontophoresis

Iontophoresis is a non-invasive method of systemic and local drug delivery using an electric field. Iontophoresis enables diffusion of the selected drug via skin, mucosa, enamel, dentin, and other tissues. The amount of delivered therapeutic molecules is about 10⁻2000 times greater than conventional forms of delivery. Among other fields, this method is used in dentistry, ophthalmology, otorhinolaryngology, and dermatology. According to related literature, the most important drugs studied or administered by iontophoresis are: Local anesthetics, opioids, steroids, non-steroidal anti-inflammatory drugs, antibacterial drugs, antifungal drugs, antiviral drugs, anticancer drugs, fluorides, and vitamins. The present review covers current available data regarding the selected medicines used in iontophoresis. Furthermore, indications and conditions of iontophoresis application are reviewed.

Iontophoretic Drug Delivery in the Oral Cavity

Iontophoresis is a noninvasive method to enhance systemic and local drug delivery by the application of an electric field. For systemic drug delivery in the oral cavity, iontophoresis was studied primarily for transbuccal delivery. Significant enhancement of drug delivery was observed in buccal iontophoresis compared to passive transport for different drugs. For local drug delivery in the oral cavity, iontophoresis could enhance drug penetration into the enamel, dentin, and other oral tissues for the treatment of oral diseases. Iontophoresis was evaluated in dentistry such as to produce local anesthesia and treat tooth decalcification and hypersensitivity, but this technology has not been fully utilized. The most common drugs in these evaluations were fluoride and lidocaine. In general, there is limited knowledge of the mechanisms of iontophoresis in the oral tissues. In vivo animal and human studies have suggested that iontophoresis is safe in the oral cavity under the conditions investigated. The present review covers the topics of iontophoretic drug delivery in the oral cavity for both systemic and local treatments. The anatomy and diseases in the oral cavity for iontophoretic drug delivery are also briefly reviewed, and the challenges for this drug delivery method are discussed.