Abstract
Atrophy and infection of the tongue mucosa contribute to dysgeusia resulting from changes in lingual papillae. However, influences of the changes of lingual papillae on oral mechanoreceptive sensation is unclear. Previous studies have suggested that filiform papillae function as a unit of the mechanoreceptive system and play an important role in somatosensation. We hypothesized that lingual papillae including filiform papillae participate in intraoral texture sensation. The aim of present study was to investigate the relationship between morphometric characteristics of lingual papillae and the texture sensation in tongue-hard palate. Sensory evaluation was performed in 10 healthy participants to evaluate the sensitivity of the tongue-hard palate to granularity. The sample food was an aqueous suspension containing crystalline cellulose, with an average particle diameter of 50 μm, and a concentration of 0 to 6.4 wt%. The participants were divided into high- or low-sensitivity groups (n=6 vs. 4) by evaluating the sensitivity to the granularity of the suspension. To assess the quantitative and morphometric parameters of lingual papillae, the surface roughness defined by JIS was measured by using X-ray micro-CT for image analysis of the surface configurations, which were recorded by silicone rubber impressions taken from the anterior region of the tongue. A concentration of the sample for determining the granular sensitivity threshold ranged from 0.4 to 3.2 wt%. Comparison of the high- and low-sensitivity groups revealed that the root mean square deviation (Rq) and arithmetical mean deviation (Ra) were significantly larger in the high-sensitivity group. In contrast, the lowest valley (Rv) was significantly larger in the low-sensitivity group. These results suggest that the morphometric characteristics of lingual papillae, evaluated in terms of surface roughness, may play a role in intraoral texture sensation.
