Statistics of Partial Denture Based upon Our New Idea of Classification

Abstract

In order to make the former system Nakazawa's (1944) more rational for the convenience of practical application, our reformed and developed, system of classifying partial dentures was advocated and while on this subject the statistical survey of partial dentures following this new classification was investigated. The former classification was mainly based upon the position of the remaining teeth, but we have found it difficult to classify some cases when we depend upon this old system of classification and have attempted to subdivide in further detailed steps.
In the former paper, Nakazawa has classified the partial dentures from following foundation.
I. From the teeth restorated with denture:
A. Dentures restorating incisors and cuspids (Anterior teeth-Denture) shown in Fig. 1, 2
B. Dentures restorating bicuspids and molares (Posterior teeth-Denture) Fig. 3, 4, 5
C. Combined type of dentures A and B (Anterior and Posterior teeth-Denture) Fig. 11, 12, 13
II. In accordance with the condition of the edentulous ridge, opened or closed, the above classified “Posterior teeth-Denture” are divided respectively into:
a. Dentures attached only anterior (free-end) Fig. 3, 4, 11, 12
b. Dentures attached both anterior and posterior (intermediate) Fig. 5, 7, 13, 15
c. Combined type of a and b (combinated) Fig. 8, 9, 17, 18
III. In accordance with whether the edentulous ridge is beyond the median sagittal line or not, “Posterior teeth-Denture ” and “Anterior and Posterior teeth-Denture” are further divided respectively into:
a' unilateral Fig. 5, 8, 13, 17
b' bilateral Fig. 4, 7, 16, 18
Moreover, as you see, it is probable that an edentulous space may be intersected by the existence of the remaining teeth in two or more parts of space. On that occasion a set of “bilateral free-end denture” must be differentiated from the bilateral continuous free-end denture. Accordingly, we further subdivide the above classified dentures from. whether the edentulous space involves remaining teeth or not.
5, 000 partial dentures constructed by the members of the infirmary attached to our school from April 1950 to March 1953 were statistically investigated. We have obtained the following results.
1. The percentages of “Anterior teeth-Dentures” are 11.8%, “Posterior teeth-Dentures” 47.0%, “Anterior and Posterior teeth-Dentures” 41.1%.
2. As for the “Posterior teeth-Dentures”, “free-end-dentures” (19.3%) and “intermediate-dentures” (20.60) are comparatively numerous than others, and. “combination-dentures” (7.1%) are less than others. Among “free-endden tures ”, “bilateral-free-end-dentures” (11.9%) and among “intermediate-dentures” “unilateral-intermediate-dentures” (17.8%) are distinctively more than others.
3. As for “Anterior and Posterior teeth-Dentures”, “combination-dentures” show-the greater percentage of 19.9%, while “free-end-dentures” 12.6%, and “intermediate-dentures” 8.7%.
4. The denture for the lower are more than that for the upper. The percentages of “Anterior teeth-Dentures” for the upper, and that of “free-end-posterior teeth-dentures” for the lower are high rate than that for lower or upper.
5. A comparatively few number of “bilateral-intermediate-posterior teeth-dentures”, “unilateral-combination-posterior teeth-dentures”, “unilateral-free-end-anterior and posterior teeth-dentures ”, “unilateral-intermediate-anterior and posterior teeth-dentures ”, and “unilateral-combination-anterior and posterior teeth-dentures” are not so important from the statistical point of view, but have much to note from the practical point of application,