The Effect of Viscosity of Oral Moisturizers and Residual Ridge Form on the Retention Force of Maxillary Complete Dentures

Aim: To study the effects of viscosity of oral moisturizers and residual ridge form on theretention force of maxillary complete dentures.Methods: Thirty-five maxillary edentulous participants were recruited. Three types of oralmoisturizers with different viscosities, artificial saliva, and denture adhesive were used. Thesewere applied between the intaglio surface of the denture and basal seat mucosa. The centralincisor was loaded 45° upward to the occlusal plane. The force needed to dislodge the denturewas measured using a digital force gauge. Dental impressions of the polished surfaces andintaglio surfaces of the maxillary complete dentures were obtained. Then, duplicate dentureswere cast using auto polymerizing acrylic resin. The buccolingual molar residual ridge form wasassessed using the dental impressions. The duplicate denture was used to measure the positionalrelationship of the central incisor edge, anterior residual ridge crest, and posterior border ofdentures. The effect of residual ridge form on retention force was analyzed.Results: The gel-type oral moisturizer showed significantly greater retention than theother types (P < .05). The retention force and buccolingual molar residual ridge form were notcorrelated. As the ratio of the distance from the central incisor to the anterior residual ridgecrest and the distance from the anterior residual ridge crest to the posterior denture borderincreased, retention force decreased (r = -0.352; P < .01).Conclusion: The results indicate that the retention force of dentures is affected by oralmoisturizer viscosity and the relative position of the anterior residual ridge crest