The Relation between the Physical Properties of Oral Moisturizer and Denture Retention Force

Abstract

Denture wearers complain of oral dryness as the retention force of the denture decreases. The purpose of this study is both to clarify the effects of different types of oral moisturizers and their physical properties on denture retention, and also to determine whether an oral moisturizer can serve as a denture adhesive. Twenty-one types of oral moisturizers (sprays, liquids, and gels), and two types of denture adhesives as controls, were used as test materials. Spinnability tests were performed with a NEVA METER^®. Viscosity tests were carried out using a Brookfield rotational viscometer. The retention strength was measured as follows: each material was placed between the model and the experimental denture base, and a ring placed at the center of the denture base was pulled at a speed of 0.5 N/sec using a spring balance. A statistical comparison of the test results was performed using both a one-way ANOVA and a multiple comparisons test. The mean viscosity for the spray type oral moisturizer was 1.5×10² mPa·s, 3.0×10³ mPa·s for the liquid type, 1.5×10⁵ mPa·s for the gel type, and 1.4×10⁶ mPa·s for the denture adhesive. The mean retention strength was 3.6 N for the spray type oral moisturizer, 14.4 N for the liquid type, 30.1 N for the gel type, and 36.0 N for the denture adhesive. There was a positive correlation between the viscosity and the retention strength of the oral moisturizers (r=0.98, p<0.01). No correlation was found between spinnability and viscosity or between spinnability and retention strength. The gel type oral moisturizers had the same level of viscosity and provided the same retention strength as the denture adhesives used as controls, suggesting that a gel type oral moisturizer may serve as a denture adhesive.