IL20165A - Artificial teeth - Google Patents

Description

i The present invention relates to Improvements in the production of artificial teeth, and particularly in the production of members which are to be inserted into the bone structure of the human jaw and which are to support a crown, and especially jacket-type crowns. The members according to the invention consist of a pin which is to be inserted into the bone structure of the jaw and a support for the crown, the angle defined, by the pin and its crown supporting portion being-^jf a given predetermined magnitude according to the individual anatomic requirements of the patient* Members supporting a dental crown, and being in the form of pins which are inserted into the tooth root in the jaw, are commercially available in many forms and shapes, There are simple pins either having a smooth outside or being fluted, there being known also slender cones and there are further known pins which are stepped, i.e. having different diameters at different portions of the pin. Finally there are also pins which have a head-like wider end part. Λ qrEown, say a jacket crown destined to fill a gap in a patient's mouth should fulfill the following conditions: the crown must be fast with the pin and must withstand all stresses incident during chewing and such stresses must be transferred advantageously onto the holding pin. The crown -furthermore - must fit properly into the row of the natural teeth and must be aesthetically acceptable both in appearance and position.

Since meeting these conditions is closely connected with portion my be made from one piece.

The invention will- now be described in .connection with ·..-/ : '/; the annexed draxfings. · In Fig.l there is shown a piece of the starting, i.e..rod material, while Fig.2a, shows schematically, in a frontal view a pin according to the invention. Fig.2^1 shows the same pin in elevational section Fig.3 is a two part press form for shaping tho pin, Fig.4 is the same form after conclusion of the shaping step, Fig.!5a is a lateral sectional view of a toot while Fig.5b is a elevational frontal section. Fig.6a is a lateral view of a tooth and Fig. 6b is a view of the same tooth inserted into the root in the jaw* Fig. 6c is a lateral view of a slightly different form, of a tooth, and Fig, 6d is a plan view thereof.

From a round rod of appropriate raw material of sufficient strength the portion a-β is severed mechanically and is worked up to the desired pin. The new pin comprises a conical slender portion 1 which at its lower end is provided with circumferential grooves 2. In its upper part the pin is provided with a socle 3 and finally a conical head portion 4· So far we have described the making of the "blank" for making the final pin. The portion 1, (the pin proper may be integral with the head 4, or a.pin 1' may be inserted in a distinct head 4', as shown in Fig.2b.

The mould comprises as an upper part a hollow cylinder 5 the cavity of which is slightly conical and into which is press fitted a slightly conical central part 6. In the bottom portion of this latter.is provided a negative i.e. a shaping cavity which corresponds in profile to parts 1, bores passing through this form part, namely the central portion 6 and the hollow cylinder 5.

In the lower part of Pig.5 there is shown the mould portion 12 in which is provided a cavity 14 being of the shape of the head portion which is to be made and which is orientated in relation to the pin proper according to the anatomical conditions of the jaw of the particular patient for whom the prosthesis is made. Once the head portion 4 of tho pin is positioned in the cavity 14 and, the form part 5 ibeing- set on top of part 12 (the parts 5,6 being held so as to prevent their being shifted sidewardly), the head portion 4 can be pressed in the sense of arrows F into the cavity 14 by moving down part 6 until the lower side of the upper mould porian 6 contacts the upper face 13 of the lower mould portion. . " Now parts 5 and 6 can be lifted from part 12, the newly formed head 4 being thereby removed from the cavity 14.

T.

Now,, by turning the lever 11 the pin comprising positions 1, 2, 3» 4 is pushed out of the mould by the cam. In this way a product of high precision is attained and the axis of the pin proper and the crown portion are properly orientated in relation to one another.

Figs. 5a and 5b show in lateral view^ and in frontal view a tooth which has been made according to the new method. The crown 16 is held on the head portion 4 by a cement layer 15.

.Figs. 6a, 6b and 6c show lateral views of three such teeth. It can be soen that the edge of every tooth 4 may be differently positioned in relation to i s axis y-y. The or can "be behind the latter as shown at 17" in Fig. 6c. It should especially be noted that the tooth according to Pig.6c is provided at its base with an abutment 18 which can be seen also in ig.6d. This abutment serves in all those cases where a turning about the axis y-y should be obviated.