Of many methods of impression taking in the design of a complete denture, they can be roughly classified as pressure or strong and non-pressure or weak methods in terms of a degree of pressure exerted on the jaw membrane.
In the design of a partial denture, particularly that of a free-end denture, a strong impression taking method is generally recommended for the reason that it decreases a burden on the part of clasp teeth and, inversely, increases a burden capacity of membrane beneath a plate.
Although there is available a fair amount of published literature on this pressure impression taking method, they are devoted to the relationship between different methods and jaw membrane, there being no report dealing with possible effect on the occlusal force and mastication subsequently.
For this reason, in the present study the author was concerned with differences of impression taking pressure on the jaw morphology and occlusal force in the manufacture of a free-end partial denture whose burden is placed on the apical mucosa.
For the prescribed purpose, 7 impression taking conditions were established for the determination of strong and weak pressure methods to be adopted.
With a view to finding out what effect the differences in impression pressure would have on the jaw membrane and occlusal force as well, the membrane characteristics of a selected sample of 10 subjects consisting of 3 males and 7 females for whom a free-end partial denture was indicated were then measured.

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In recent years, much advance has been made in the realm of dental precision casting and although there is available a fair amount of the published literature on the dimensional precision, studies dealing with the surface roughness of cast structures seem to have been relatively neglected.
The clasps, burs and plates in partial denture are, unlike other crown prosthetics that are placed in contact with the teeth through a medium of cement, put in direct contact with the teeth and jaw mucosa and, for this reason, it is necessary that cast structures should be polished with a minimum degree for the purpose of enhancing their fit.
Therefore, the surface roughness of cast structures influence not only their fit, but also it is closely related to a possibility of caries incidence and an inflammation of jaw mucosa.
In the present study, the author was concerned with degrees of the surface roughness owing to various materials and during each stage of their processing. At the same time, efforts were made to find out how the roughness would be reproduced inside the clasps which are in direct contact with the teeth in terms of each stage of processing and in the final stage of finished cast structures.

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In the partial denture design, it is very complexe because of the fact that its range covers one missing tooth to a part of a remaining tooth and, for this reason, the relationship between the two are of various kinds.
In these conditions, it is required that a good refractory working model should be constructed for the purpose of manufacturing a cast plate that possesses a desirable fit. In other words, in designing a partial denture cast plate posessing a desirable fit a need is felt to investigate into various phases of dimensional changes of a refractory working model in detail from a clinical point of view.
In the present study, therefore, the author was concerned with 2 types of phosphate-bonded investment (Hi-vest D and Tai-vest) widely used in the manufacture of Co-Cr alloy cast plate and compared the differences between the effects of Kennedy's 4 kinds of defective types and 3 different impression taking methods (alginate, combined alginate with individual trays and combined alginate with commercially available trays) on a heatresistant model.

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