Fucidic acid, of which fucidin is the sodium salt, was isolated from the fermentation broth of the fungus Fucidium coccineum (GODTFREDSEN et al.) . Fucidin is a new antibiotic and mainly active against gram-positive microorganisms and Neisseria [2-5]. The chemical structure of fucidic acid is shown in Figure 1 , and related to that of cephalosporin P1. Consisting of the cyclopentanoperhydrophenanthrene ring system, it is important to determine if fucidin has the measurable effects as a steroid hormone. From such a point of view, there has been published only a report on the human being , though it is insufficient. In the present study, the steroid hormonal activities of fucidin have been investigated in the experimental animals.
Fineness, time of setting, compressive strength, linear thermal expansion, hygroscopic expansion, normal setting expansion, and surface defects of alloy castings were determined using casting investments of three types thermal inlay, hygroscopic inlay, and thermal partial denture. The use of the normal setting expansion combined with either the hygroscopic or thermal expansion to compensate for the shrinkage of casting gold alloys is discussed. The values for significant properties of some commercial casting investments, along with the corresponding requirements of American Dental Association Specification No. 2 for Casting Investment for Dental Gold Alloy, are presented. The setting times of all the investments were in the lower or middle third of the 5 to 25 minute range permitted by the specification. Compressive strengths of most of the investments were 11/2 to 21/2 times the minimum specification value. Setting expansion in air was generally near the specified maximum while setting expansion in water was near or below the specified minimum.
Presently available observations from these examinations of teeth treated by direct and indirect pulp capping suggest that the dentinal response to indirect pulp capping is mild, as evidenced by the numbers of cases with tubular dentin or no new dentin formed after treatment. Tt appears likely also that if the rate of new dentin formation is greater during the first three months following direct pulp capping, it does not remain so since there is some evidence that both treatments eventually result in about the same amount of new dentin. The absence of a dentin bridge following direct pulp capping is of unknown significance in cases where clinical and histological examination reveal a normal pulp.
Available published literature on the antibacterial effects of various medicaments used for the treatment and prevention of dental caries of bacterial origin [1, 2, 3, 4, 5] is almost confined to studies from a bacteriological point of view and, for this reason, it does not provide sufficient evaluation of their clinical efficacy. For the purpose of making good this deficiency, therefore, the present authors performed a series of tests in which clinical efficacy was highlighted on the 5 dental cavity varnishes commonly in use in the general dental practice.
As has been indicated in a previous report , the authors carried out a detailed measurement of physical properties during the setting procedures of zinc phosphate cement and established the facts that 1) an increase in powder-to-liquid ratio will result in the retardation of setting speed and 2) although changes in an enviromental temperature are not directly linked to either retardation or promotion of speed in any regular manner, there is found a peculiar phenomenon in the neighborhood of 27°C. Since this is similar phenomenon which takes place in the setting mechanism of alginate impression material studied by HIGASHI , it provided a basis for our inference that the setting of this kind of cement may be explained as due to the gelation of colloidal particles. As for changes in pH readings, they increased in proportion to a rise in temperature but its manner of rise was somewhat checked in the neighborhood of 27°C. On the other hand, although the internal temperature of cement owing to heat generation was in parallel to that of external or environmental temperature, nothing peculiar was observed around 27°C. As the setting of this kind of cement has been hitherto ascribed to the crystallization of phosphate salt through a chemical reaction of zinc oxide with phosphoric acid, the above inference of ours may prove significant but, before it is fully substantiated, we still need many other items by way of irrefutable evidence. Along this line of thinking, our effort in this part of studies was directed to possible influence of water to be added to the reaction with specific reference to the setting speed.