Differences in Lip Support with and without Labial Flanges in a Maxillary Edentulous Population. Part 1: Objective Analysis.

Abstract

To study the objective differences in lip support using common facial soft tissue markers, when evaluating patients wearing a maxillary denture with a labial flange in comparison to an experimental flangeless denture. A total of 31 maxillary edentulous patients who were esthetically satisfied with their existing maxillary denture were recruited in this clinical study. The maxillary denture was then duplicated in clear acrylic resin. Two standardized full-face digital photographs (frontal and profile) were made with the duplicate denture in the mouth. The labial flange of the duplicate denture was then removed from first premolar to first premolar region, to create the experimental flangeless denture. It was returned to the oral cavity, and 2 additional full-face digital photographs were made. The differences between these images were studied using 5 facial anatomic markers (subnasale, labrale superior, stomion, nasolabial angle, lip thickness). A paired sample t-test was used to compare differences in measurements for various anatomic markers using an alpha value of 0.05. For profile images, there were no statistically significant differences between photographs with and without a labial flange for anatomic markers- labrale superior and stomion (p < 0.05). There was a statistically significant difference for subnasale as well as the nasolabial angle but the magnitude of the difference was too small to be clinically significant (p < 0.05). For frontal images, there was no statistically significant difference in lip thickness between photographs with and without a labial flange. Additionally, there was no association between differences in measurements and patient-related factors such as gender and prior years of edentulism. Removal of a labial flange in a maxillary denture resulted in minimal and clinically insignificant anatomic differences in lip support between flange and flangeless dentures, when analyzed in frontal and profile images.