Masaru Hada

Clinical Evaluation of Chemical Denture Cleaning : Change of the Color at the Palatal Mucosa under the Denture

Recently, denture stomatitis was found in the oral mucosa of most denture wearers. It is generally accepted that the significant cause of denture stomatitis areinfection with Candida albicans. Dentists indicate that the denture plaque with Candida albicans is removed from denture surface by both mechanical denture cleaning and chemical denture cleaning. The color in the oral mucosa depends on the infection such as gingivitis and denture stomatitis.The purpose of this study is to examine the effect of the denture cleaner on the oral mucosa in the Candida-induced denture stomatitis by the change of the color in the oral mucosa.The results were as follows:1. The denture stomatitis became well after chemical denture cleaner was used. Especially, the infection at the posterior ofpalate were not found.2. The infection region have 2.8 R-5.1R in Hue, 5.7-6.1 in Chroma, 6.8-7.7 in Value. On the contrary, the non-infection region have3.8R-7.5 R in Hue, 6.4-6.9 in Chroma, 4.0-6.4 in Value.3. The color differencebetween the denture-bearing mucosa when no chemical denture cleaner was used andthat when denture cleaner was used, provided a method for estimating the effect of the denture cleaner. The greater color difference were found at the palate.

Development and application of an optical system to measure the movements of organs with soft tissue

We proposed a new optical system to measure the movements of less accessible organs with soft tissue. The sensor unit is composed of a phototransistor and two LEDs. Two LEDs of light sources are driven by two phase signals with phase shift of 90 degrees. The distance between the sensor and the measuring object can be obtained as the function of the phase angle of reflex light signal detected by the phototransistor. The system can be easily constructed and provides simultaneous recordings of multiple points with the fast response in real time. The Relative precision is 0.5 mm and the resolution is 0.05 mm. Output characteristic of the system was less affected by the reflection factor of the object. We conducted to observe the tongue movements in speech production.