有床義歯破損例の臨床的観察

抄録

There are three kinds of disturbances ; they are
1) fracture of the denture base
2) fracture of the clasp
3) broken or displacement of the artificial teeth from a denture
To determine the frequencies and portions of these disturbances, we have made a clinical sur-vey of the broken dentures.
The purpose of this survey is to improve the way of repairing dentures or to find the measure of prevention.
The cases examined were not selected of the 184 fractured bases, 127 were removable partial dentures, 91 in the upper and 36 in the lower and 57 were complete dentures, 48 in the upper and 9 in the lower.
Approximately twice of five fold as many were found in the upper dentures as in the lowers. In the complete dentures, cracks were .originated mainly from median line or cuspid areas.
In the removable partial dentures, fracture were originated from anchored area of clasps, area of isolated remaining tooth and boundary between bar and base material.
The percentage of broken artificial teeth of upper dentures was larger than that of lower, 2 times in partial dentures and 4, 3 times in complete dentures.
Anterior teeth (incisors and cuspids) had larger percentage than that of posterior teeth.
Broken clasps were found in the upper dentures of 18 and in the lower denture of 12.
The cause of these damages seemed to resolve into malconstru, .tion and inadequate indikation of clasps and not material itself (18-8 steel wire or co-cr wire) .