At that time Nakamura dentist recommended me to definitely announce at the dental ergonomics society meeting When being perplexed, he said that you have a good friend Dr. Y. Sakashita who is opening a dental clinic in the nearby Ohbayashi Building. When I talk to Y.Sakashita he is willing to support me as well. We prepared necessary materials for the conference so we finished the first conference present. The interdental brush is used in accordance with the size between teeth, so there are various sizes. Therefore, with S as the standard size, we decided SS s as medium size and SSS as extremely fine. The part where the gums between the teeth are raised is called the interdental papilla. This falls with age. The place where teeth and teeth stick on it is called the adjacent face. The distance between this adjacent surface and the interdental papilla upper part changes with age. The size was determined based on this distance. Later, the size was unified at the Toothbrush Industry Association, but since there are no interdental brushes around, anyway it is a setting that the standard is considered necessary. The reason for this setting was announced by the 5th Dental Ergonomics Association in 1990 (Aichi Gakuin university, dental division.)
Furthermore, since the ergonomics society is an academic pursuit of ease of use, I explained the reasons for the length and thickness of the steering wheel. Reaching to the back teeth (molar), the length of the easy-to-use handle is 55 mm, the thickness is set to 3.4 mm of the contact as it grips with three fingers. So you can convince your ease of use once you use it. Although it has been over 30 years since its release, we have strong fans. With this ergonomic idea you can be taught by the teachers' enthusiastic efforts about the importance of doing things making things, and Doctor Sakashita's gracious guidance. There was no translation and I felt a sense of being blessed with good teachers. Considering that packaging is one of the medical supplies to clean the narrow interdental space, we packed one by one with sterile paper and sold it. Then it gradually expanded. It is said to want also for a narrower interdental space, adding 4S (superfine). Furthermore, L (extremely thick) and LL (super-thick) are also sold, as in the wider gap, and the quantity is smaller than other sizes but accepted by the elderly.
In this year (1990), Y. Goto joined as a technical manager. In the same year, "Toothpicks Gallery" was opened, and Saturday's public release every week began. I thought that it was necessary to convey the history and culture of "toothpick" as a local industry. I wanted to contribute to the local in some way because we have continued the job for many years in the same place. In connection with this establishment, we consulted with Mr. Y. Mitobe, who was an official of the prefecture and was at the trade pavilion at that time. I got guidance in all aspects including the method. After all, because people never had the factory seen, I received an indication from orderly cleaning. Place the cardboard on the wall of the building on a flat stack. A lot of dust comes out when we take it. After finishing the work, he got close to home on the way home and as soon as he got it, he picked up a broom and a rag I was able to start cleaning. One of the unforgettable words is "different from old and dirty".
更に人間工学会は使い易さを追求する学問であるから、ハンドルの長さと太さの根拠を説明した。奥歯（臼歯）に届き、使い易いハンドルの長さは５５ミリ、太さは三本指でつまむのでその接点の３．４ミリに設定した。だから一度使って下さればその使い易さに納得いただける。発売後30年以上経過したが根強いファンがいて下さる。 この人間工学的な発想でものづくりをすることの大切さを会員の先生方の熱心な指導で教えられると共に坂下先生の懇切丁寧な指導がなければ、素人の私が大それたことが出来る 訳がないし、よい先生方に恵まれていると痛感した。 包装は狭い歯間部を清掃する医療用品の一つだからと考えて、一本ずつを滅菌紙で包装して販売した。
