Discussion
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DENTAL EROSION, HYDROXYAPATITE, PROTEIN ALLERGY
In the present study, we aimed to examine the enamel erosion preventive effect of the experimental Arg-NaF varnishes (at 2, 4, and 8% Frequently consumed by children, paracetamol and chlorpheniramine, were used for PLM-mediated erosive challenges in the present study as pH of these PLM were 4.74 and 2.50, respectively. A severe erosive pattern was observed with chlorpheniramine, primarily due to the pH of the medicament. Furthermore, chlorpheniramine maleate is the active ingredient of the Chlorpheniramine Maleate Syrup (used in this study) which when dispensed in the oral environment dissociates to form a chlorpheniramine base and maleic acid. The acid component chemisorbs to the hydroxyapatite (HA) through ionic interactions [The CPP-ACFP (as MI varnish®) has been available in the market for several years and is known to reduce surface roughness caused by dental erosion [The erosivity of PLM depends on several factors including the content pKa, temperature, viscosity, and the consumption frequency. As reported earlier, acidic PLM can result in softening of enamel and increase the risk of erosive wear [Based on the overall results of PLM-mediated erosive challenges, it can be explicitly deciphered that the varnish treatment groups exhibited an order of protection against erosive wear when challenged with PLM containing chlorpheniramine (pH < 3.0) as opposed to paracetamol (pH > 4.50) whereby all treatment groups demonstrated no additive preventive effect. Therefore, forthcoming, the results with chlorpheniramine-mediated erosive challenges and the subsequent effect of varnish applications are discussed. With SPA, the measured Ra for all treatment groups was significantly lower than the negative control. However, the results with AFM identified significant differences between the treatment groups. This is likely as the 2D surface profiler runs across a straight line while detecting limited surface characteristics roughness. Whereas, the AFM scans surface area and detects finer details while characterising the surface of interest and thus, such differences between characterization were identified.The results of Ca/P determined using SEM-EDX align well with the results of Ra estimated with AFM whereby 4%/8% Arg-NaF and CPP-ACFP had significantly higher Ca/P ratio than the baseline and the negative control. The higher Ca/P ratio than the baseline could be attributed to the precipitation of Ca and POThe results of the present study suggest that incorporating Arg at 4%/8% Although the study was comprehensively performed to address the objectives, the study limitations include being an in vitro investigation, experiments on third permanent molars due to difficulty in obtaining sound primary teeth, and teeth-related characterizations limited to SPA, AFM, and SEM-EDX. However, the results of the study present a platform for further investigation of the 4%/8% Arg-NaF varnish as a professionally-deliverable erosive wear preventive agent, which can be applied to patients with suspected or proven milk protein allergy whereby application of MI varnish® is contra-indicated. To delineate the erosive wear preventive potential of Arg-NaF varnish on a larger scale, future research targeted on investigating the erosive wear preventive effect of Arg-NaF varnish against the regularly consumed acidic fruit juices and soft drinks can provide additional insights.