[A study on measurement of hardness of oral mucosal lesions].

This study was designed to estimate objectively the hardness of the oral mucosa which is not directly supported by the bone. A new, easy-to-use hardness-measurement apparatus for measuring the oral mucosa free of the underlining bone was manufactured for trial use. The hardness values of the oral mucosa were evaluated quantitatively, resulting from pressing 2 mm into the mucosa with a 2-mm-in-diameter hand-held probe coupled to the hardness-measurement apparatus. Experimental and clinical confirmation was made that practical errors in hardness values are quite permissible when using this apparatus. This fool-proof method was further examined in extensive clinical application. The normal mucous membrane of the tongue, the floor of the mouth, and the cheek respectively measure 4.45, 4.33, and 2.96 gf on average with this apparatus. Examining 26 cases of squamous cell carcinoma on the tongue, the floor of the mouth or the buccal mucosa (16.87-80.32 gf) revealed that the value of measurement of squamous cell carcinoma was as much as 2.31-19.06 times in comparison with the normal mucous membrane. Squamous cell carcinomas were ascertained to be statistically harder than the normal mucosa (p < 0.001) and the tumor margins may be far more precisely clarified with this apparatus than with the human finger alone.