Physiochemical Analysis of Fluoride Availability and pH in Moroccan Mouthwashes: Clinical Implications for Enamel Safety

Abstract

A bstract Objectives: Fluoride mouthwashes are essential tools for caries prevention; however, their efficacy and safety depend on accurate fluoride concentrations and non-erosive pH levels. Deviations from labeled specifications can compromise therapeutic outcomes or pose risks to dental enamel. The aim was to quantify the available fluoride concentration and evaluate the pH of commercially available mouthwashes in Morocco, benchmarking them against international ISO standards and clinical safety thresholds. Methods: Twenty commercially available mouthwashes were collected from Moroccan pharmacies and supermarkets. Fluoride concentration was determined using the Belcher–West colorimetric method with Alizarin complexone, based on spectrophotometric measurements at 618 nm following appropriate calibration and method validation. The pH of each product was measured using a calibrated digital pH meter. The accuracy of fluoride labeling was examined based on international quality standards. Statistical analysis included a 15% deviation benchmark (ISO 16408) and Pearson’s correlation to assess the relationship between fluoride stability and acidity. Packaging materials (polyethylene terephthalate/high-density polyethylene) were assessed for their impact on physicochemical stability. Results: Among fluoridated mouthwashes, 80% ( n = 8) complied with international quality standards, showing relative deviations between 0.71% and 5.76% from labeled values, while 20% ( n = 2) were non-compliant due to significant under-labeling. Measured fluoride concentrations ranged from 95.50 ± 0.78 ppm to 475.90 ± 3.55 ppm, with sodium fluoride identified as the active ingredient in all fluoridated formulations. All non-fluoridated mouthwashes exhibited fluoride levels below the detection limit (<0.7 mg·L −1 ). The pH values varied widely across products, ranging from 3.9 to 8.0 in fluoridated mouthwashes and from 2.8 to 5.5 in non-fluoridated formulations. No statistically significant correlation was observed between fluoride concentration and pH among fluoridated products, indicating that fluoride presence was not restricted to neutral or alkaline formulations. Packaging analysis revealed a consistent absence of pH information on product labels. Conclusion: A substantial proportion of Moroccan mouthwashes fail to meet international standards for fluoride labeling accuracy. Furthermore, the presence of acidic formulations in the market necessitates stricter regulatory oversight to ensure enamel safety. Clinicians should be cautious when recommending specific low pH formulations to patients with high erosive risk.