In the published studies dealing with the growth processes of human teeth from the anatomic or embryologic approach, the usual means of expressing the development of their roots is in terms of years of individuals from their births [1-6]. In Particular, the permanent root with reference to its degree of development is often used as a unique criterion in the field of biometry and for this reason, there is known the concept of root age [7-12]. In connection with our 10-year consecutive survey of succedaneous and permanent dentition in the Japanese children [13-16], the authors have turned their attention to the fact that those teeth, I1, I1, Pm2, Pm2, which received undue stress in the period when their roots were still imperfectly formed will tend to result in abnormally shorter roots . If the above finding is valid in all the cases, it follows that there will be created a definite ratiowise difference between the lengths of normally formed crown and root and those of abnormally formed crown and root under the conditions above specified, i.e., between those physiologically replaced by the successors and those replaced by abnormal ones having shorter roots. The present study was conducted to see whether the above contention could be justified.
The authors have been concerned with examinations of various medicaments used for the purpose of endodontic treatments. The present paper, which forms a third part of our comprehensive studies on the subject, relates to the antibacterial effects of a variety of pulp capping and root canal filling agents widely used in current endodontic practice.
The purpose of our studies was to determine the corrosive behavior of dental restorative alloys in the mouth and, at the same time, to examine them from a dental health point of view. The conclusions are as follows : 1. Even the copper alloy which is commonly supposed to have a high degree of corrosion actually has as small weight loss in the mouth as 0.022 to 0.034 mg/cm2 for a day. 2. The type of amalgam which is widely used in many countries today has the weight loss in vivo as little as 0.0063 mg/cm2 a day. 3. The basic reason why these alloys are not corroded as is generally supposed is that the salivary secretion has the benefit of keeping the mouth clean. It is also due to the fact that the saliva works to inhibit the corrosion of alloys. 4. As it became clear by our testing that 1950 Ministry of Welfare corrosion test was not realistic as a means of expressing the corrosive behavior of dental alloys, it was removed from the specifications. 5. Within the same oral cavity, the degree of corrosion varies from area to area, that is, anterior teeth, posterior teeth, occlusal, buccal to lingual or proximal surface. By observing the copper alloy restorations after they were removed, the corrosion is most pronounced on the proximal surface.
The dentinal tubules are differently studied from histologic, histochemical, electron microscopic or historadiographic approaches. In the present paper, the authors were concerned with an application of scanning electron microscope, a recently developed technique, to study the dentinal tubules in their longitudinally sectioned state.
GOBAB is an amino acid with anti-inflammatory activity, discovered by NAGAI and his collaborators. Its position isomer, 4-amino 3-hydroxy amino acid, has been used clinically as an anticonvulsant since 1959. The anti-inflammatory action of GOBAB is manifested in a specific fashion as never seen with conventional antiinflammatory substances. The discovery of the drug may be considered to be of such significance as to upset the traditional concept of anti-inflammation established by SELYE. In this paper, the author deals with such a concept in relation to his own viewpoint while discussing recently published clinical results with GOBAB.
Vitamin C in its various preparations is one of the most commonly administered drugs in dentistry. In connection with many researches related to the poisoning of many pharmaceuticals, research endeavors are also active in the antidotal action of these drugs. TAMURA, one of the present authors, published his experimental studies on the elimination of an injurious by-effect of promine [1, 2] and also those dealing with leucine against caffeine , substances having antidotal effects on morphine and nicotine  and anti-alcoholic agent . Although the possibility of vitamin C poisoning has drawn the attention of medical and dental profession for a long time, almost nothing is known about its effect when administered conjointly with some form of amino acid. In the present report, the authors are concerned with the antidotal mechanism of vitamin C and glucose-cysteine against acetaldehyde responsible for the alcoholism and nicotine, a potent factor in the nicotinism.