Patent GB-321586-A (GB)
Title: Improvements in method of and apparatus for forming artificial dentures
IPC: A61C13/24
Filed: 1928-12-17
Abstract: 321,586. Barbour, F. W. Dec. 17, 1928. Teeth, artificial.-In a method of fitting a denture having a close-fitting flexible margin secured thereto, the flexible margin 10 is first built out by means of impression material 11 so as to fit the patient's mouth, then a mould is obtained of the built up margin, the impression material removed and the flexible margin displaced so that it. fits the mould, the denture being finally treated in the mould so as to set the flexible margin to the moulded shape. Impression material 1 carried on a tray 22 is used to form a model 2 of the mouth, preferably in plaster of paris. A dark band having an outer edge 3<a> may be scratched in the plaster to define the area of the proposed denture. If the teeth are to be fitted before completing the denture, they are first mounted as usual on wax 4 and, after fitting, are placed on the model and the wax trimmed back to about “ in. from the edge 3<a>. A strip of flexible pattern material 5, having rounded ends 5a, is next screwed to the model with one edge closely following the line 3<a> and wax 6 is employed to fill the space between the pattern and the wax 4, Fig. 5. If it is not desired to fit the teeth before completing the denture, the pattern may be applied directly to the model before the teeth and wa.x carrier are applied thereto. The model is then placed in the lower part of the flask and the teeth in the upper half and, after separation of the flask, the pattern 5 is removed from the groove 9, Fig. 7. The wax 4 and 6 around the teeth is then removed from the upper half. A flexible margin 10 made of soft rubber with a concaved surface and rounded lower edge 10<b> is now inserted in the groove 9 with the concaved side fitting against the model. The remainder of the groove 9 is filled with vulcanite rubber and the upper side of the flask is filled with vulcanite rubber as usual. The flask is then assembled and by pressure the flexible margin is forced against the model. The flask is heated and more pressure applied, a temperature of 300‹ being preferably maintained for about 2¢ hours. Having thus formed the denture with a flexible edge, some soft wax 11 is fitted to the inner side of the edge 10<b>, and the denture placed in the mouth and even pressure is exerted, this process being repeated if necessary until the desired fit is obtained. The denture is then embedded in the lower flask section 7<b>, Fig. 11. A channel 12 is then cut round the outer edge of the denture and the wax 11 is washed out to leave a groove 13. Soft tape 14 is then packed in the groove 12 so as to force the flexible margin into the groove 13. The flask sections are closed and the flask heated to 300‹ for about 15 minutes. The flexible strip, which is plastic at high temperatures, thus assumes the desired shape and it regains its resilience after cooling. In a modification, Fig. 15, the impression material 1<a> may be trimmed down to the shape of the desired denture and the soft wax 11<a> moulded to give the correct fit before making the model 2a which is now formed with a groove 15. The pattern material 5 is then placed with one rounded edge lying in the groove and the model is flasked to form a groove 9<a> into which the flexible material 10 is inserted, the packing and vulcanizing steps being then carried out as before. Existing dentures may be fitted with the flexible margin which may also be used on partial dentures. The invention may also be applied to upper dentures, in which case the flexible margin may be extended across the back of the denture to engage the roof of the mouth. If desired a vulcanite base fitted with the flexible margin may be made first, the teeth being subsequently fitted to this base and a second vulcaniza. tion being made.