Quantification of Surface Modification by Traditional Denture Cleansing Regimens

A variety of products are currently marketed for the daily maintenance of dentures. Although some products such as effervescent denture cleansing tablets are able to clean effectively without mechanical action, toothpastes and liquid denture cleansers must be applied with a toothbrush in order to best remove stain and plaque. While the potential for scratching and dulling by abrasive-containing toothpastes is well understood, it is unclear whether the simple act of brushing in the absence of abrasives (but in the presence of surfactants) will also result in some surface modification. Objectives: We examine gloss as a marker for abrasivity of three denture cleansing formulations applied by toothbrushing. Products under consideration include a typical toothpaste, an abrasive-free denture cleansing liquid, and a solution prepared from an effervescent denture cleansing tablet. Methods: In order to facilitate prolonged cycles of manual brushing, a flat “denture-on-a-stick” prototype was developed consisting of a Lucitone 199 denture acrylic base and 4 Classic acrylic incisor teeth. After being polished with 0.05µ g-alumina, initial gloss measurements were taken. Prototypes were then manually brushed by technicians trained to apply 300 grams of downforce to an Oral-B 40 soft toothbrush. Gloss measurements were taken after 200, 400, 600, 800, 1000, 1500, and 2000 brushstrokes using a Beta Gloss Meter. Results: Statistically significant loss of gloss was detected as early as 600 brushstrokes for the toothpaste with continuous deterioration of gloss through all measurements. In contrast, no loss of gloss was detected for the abrasive-free formulations. Conclusion: Abrasivity, as measured by loss of gloss, appears to be strictly dependent on the abrasive content of the denture cleanser when applied by brushing. Research supported by GlaxoSmithKline.