Section1-1. “Doctor, I can bite any food!”

Unintentional word sometimes decides a human life. Now looking back upon the past events, one word of an old woman with teeth lost “Dr. Muratsu, I can bite any food!” stimulated my desire to study vivid elderly persons.After my completion of the graduate school courses, I moved to Texas University Life Medical Institutes and then, studied the concept about “Latent disease status” (Appendix － References 44~51) which implies that apparent healthy appearance would not necessarily represent actual health conditions. Following return to Japan from the USA, I worked as an assistant teacher appointed by the Ministry of Education for the Preventive Dentistry, Detached Hospital to Faculty of Dentistry, Kyushu University. Now that I obtained the new concept, some changes were raised in my way of thinking concerning prevention of teeth disorders. More frankly speaking, it might be better to say that my eyes have been more widely opened to gaze at the truth. As the results, I can view from the different ways the already-established stereotyped concept which has been accepted as “quite natural” without any doubt on it.One day. I visited a teacher’s home to report my safe return from the USA. Incidentally, he had kindly given me a special lesson for English conversation before my departure to the States. He lived with his grand-mother at more than 70 years of age. She was very well with good complexion. However, I found that she had a full denture but to my surprise, she told me “Dr. Muratsu, I can bite any food”.Unless I had studied in the States, I would probably have disregarded this word but in the face of this elderly woman, one simple question came to my mind because I came back to Japan after study on the concept about “Latent disease status”. The questions were “This woman looks very well but is she really healthy?” and “Are teeth really indispensable for humans?”Incidentally, preventive customs to maintain healthy conditions including “Tooth brushing” include various items covering from jugging to ingestion of health-food. Nevertheless, within the limited framework of a day, we cannot afford to do everything. Therefore, in compliance with the preventive principle “To the most dangerous lesion, the most effect measure should be applied.” we must select the most practical method among the candidate procedures and implement it. Irrespective of good or bad, the obtained influence would be significant because such a method is customarily repeated every day. Based on such a preventive principle, I have so far enlightened people for their performing the preventive measures in favor of teeth including tooth brushing, while believing in the theory “To retain own teeth is important.” as a health scientist or a preventive dentist.Contrary to my belief, the said woman with a full denture was very well and she declared that she could bite any food. This was really a shock to me because I had studied preventive dentistry and then entered the postgraduate school. I might say, my mind went blank all of a sudden. When I turned my eyes to my family, my grand-mother with a full denture lived without her own teeth. I was puzzled with these examples, besides believing in “Teeth are important” but this concept was only a theoretical one which was not supported by any actual survey or scientific data. Since an old saying tells us “There are no unnecessary things under the heaven.” and loss of teeth induces difficulty in eating food, people simply consider “Teeth might be necessary.” In recent years, a term of TBM (Evidence Based-Medicine) has been extensively used in many fields and its significance was noted; however, the scientific and medical grounds to support “Importance of teeth and its significance” have not been clarified. Accordingly, such ignorance is responsible for easy grinding of teeth or pulling out of teeth.“Human beings do not need teeth?”“Without teeth, do we feel only inconvenience for eating food? No teeth provide no disorder to our health?”“Even if we lose own teeth, is it all right for us to do well by using a full denture?”Almost 60 years have passed since the end of the World War II. During such a long period of time, dental medicine has progressed significantly. However, we come across this unique question which has been disregarded by dental specialists and dentists because of its too simple features. Scientific clarification of this question seems to be the eternal theme for the dental medicine field. I faced directly such an eternal theme which comprises the starting point for the dental medicine.In the similar question “To be or not to be, that is the question” raised by Hamlet, “Are teeth necessary or not?” and “Dr. Muratsu, I can bite any food.” mentioned by that old woman triggered my agony as a scientist dealing with health problems. In more detailed health-scientific explanation, I was wondering which the truth is, either “Teeth are regarded as only a part of chewing organ. Loss of them is associated with only lowered chewing function but no influences are given to systemic health conditions and biological mechanisms.” or “Teeth are indispensable for the whole body health rather than playing a role in chewing food. Teeth are involved in certain bio-mechanisms. The said old woman would appear healthy at a glance whereas she might have latent disease states both in mental and physical conditions thereby having lowered vital functions.” This question once again haunted under the unexpected situations later.