Cytotoxic and antifungal effects of different teething oral gels: an in-vitro study

This study aimed to evaluate the effects of various teething oral gels, containing lidocaine, hyaluronic acid, and herbal-based ingredients, on cell viability and to compare the antifungal properties.

The effect of the six different teething oral gels (Gengigel Teething, Orajel Baby, Calgel, Hyland's Baby Organic Soothing Gel, Buccotherm Teething Gel and Aftamed Teething) on cell viability was evaluated through the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay on L-929 mouse fibroblast cells. The antifungal activity of teething oral gels against Candida albicans ATCC 90,028, C. tropicalis ATCC 750, C. glabrata ATCC 2001, C. parapsilosis ATCC 22,019, and C. krusei ATCC 6258 was assessed using the broth dilution method.

The cell viability analysis revealed that Aftamed Teething exhibited the highest level of cytotoxicity among the tested teething oral gel products, whereas Buccotherm Teething Gel demonstrated the lowest cytotoxicity. The teething oral gels can be ordered based on their respective cytotoxicity profiles: Aftamed Teething (IC₅₀ 4.62 mg/ml) > Calgel (IC₅₀ 33.40 mg/ml) > Gengigel Teething (IC₅₀ 122.85 mg/ml) > Orajel Baby (IC₅₀ 137.13 mg/ml) > Hyland's Baby Organic Soothing Gel (IC₅₀ 229.20 mg/ml) > Buccotherm Teething Gel (IC₅₀ 284.38 mg/ml) (p < 0.05). The results indicate that Buccotherm Teething Gel, Hyland's Baby Organic Soothing Gel and Orajel Baby did not exhibit any antifungal activity against C. albicans, while Gengigel Teething and Aftamed Teething demonstrated marginal effects at the 100 mg/ml concentration threshold. The Calgel exhibited the highest efficacy against C. albicans, with a minimum inhibitory concentration of 12.5 mg/ml (p < 0.05). From non-albicans Candida species, it was ascertained that Gengigel exhibited a modest antifungal effect on C. tropicalis and C. parapsilosis, while Calgel demonstrated a modest antifungal effect on C. glabrata. Additionally, Calgel demonstrates antifungal activity against C.tropicalis and C.parapsilosis, with a minimum inhibitory concentration of 25 mg/ml (p < 0.05).

Teething oral gels containing lidocaine, hyaluronic acid, and herbal formulations demonstrated varying degrees of cytotoxicity and antifungal efficacy. Herbal-based teething oral gels may be a more suitable option for young children compared to products containing lidocaine or hyaluronic acids, as they exhibit reduced cytotoxicity and enhanced biocompatibility. Lidocaine-containing gel may be preferred for opportunistic fungal infections, considering their high cytotoxic properties, solely to leverage their antifungal capabilities on different species.

Lidocaine-containing teething oral gel has demonstrated potent antifungal properties on both C. albicans and non-albicans Candida species, but the high cytotoxic effect revealed by the study, together with reported adverse effects, precludes its recommendation for use in infants.