After securement of brackets to teeth of a patent to be treated, an impression is taken of the mouth. The impression is removed, replicas of brackets are inserted in the impression and a simulation or model is made, as by positioning castings of the teeth made in the impression, in ideal locations in the model. Arch wires are then preformed to fit brackets on the ideal model and after preforming, the arch wire is transferred to the brackets previously mounted on teeth of the patient.
Parent Case Data:
This application is a continuation-in-part of
ser. no. 51,411 filed May 27, 1970 for "Method and
Apparatus for Orthodontic Treatment" (parent) now
abandoned. The parent application is a division of the prior
application, Ser. No. 857,351, filed Sept. 12, 1969,
entitled "Method and Apparatus for Orthodontic
Treatment" which matured into U.S. Pat. No. 3,578,744.
A reissue application for said patent, ser. no. 229,217
filed Feb. 24, 1972 is now pending.
BACKGROUND OF THE INVENTION
In accordance with what is known as the direct method of orthodontic work, bands are positioned around the individual teeth of a patient with brackets to permit connection of the bands to the arch wire and various spring wires as are ordinarily utilized. This technique requires considerable skill and judgment on the part of an orthodontist in manipulating and forming the various force applying wires so as to attain the desired movement of teeth.
In accordance with the so-called "indirect" method utilized heretofore, bands and arch wires are formed in an ideal model and then transferred to the patient. However, it is virtually impossible to secure the bands on the patient's teeth in the same location as on the model.
SUMMARY OF THE INVENTION
In accordance with the method of the invention and utilizing the apparatus of the invention, an orthodontist is enabled to perform the difficult and intricate task of forming an arch wire so as to obtain the desired tooth movement on an ideal model of the teeth of the patient while the arch wire is out of the mouth. Thereafter, the arch wire can be transferred to the patient's mouth and easily and quickly secured to brackets on the individual teeth. The teeth are then guided to the positions on the ideal model.
More particularly, in accordance with the method of the invention, arch wire brackets are secured by bands to the teeth of a patient after which an impression is made of the patient's mouth. After removal of the impression, replicas of the brackets are inserted in a corresponding position in the impression and a casting made of the teeth in the course of which the brackets will become rigidly attached to the tooth castings. Thereafter, the individual tooth castings are separated and reset in an ideal model of the patient's mouth whereupon an arch wire can be formed so as to conform to the bracket locations of the teeth in the ideal model. After formation of such wire, it is transferred to the patient's mouth, whereupon the memory of the wire will apply corrective force to the teeth causing them to move towards their ideal location.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In accordance with the method of the invention, the orthodontic brackets are mounted on bands and are secured to the teeth of a patient. An impression of the patient's mouth is taken so as to obtain an impression of the position of the teeth with the brackets attached thereto. The impression is removed from the mouth and an ideal model of the patient's mouth is made. For example, replicas of the brackets are inserted in the corresponding apertures formed in the impression. Thereafter, a casting is made in the impression so as to obtain a model of the patient's teeth with the bracket replicas attached to the cast teeth. Next, the individual tooth castings are separated by cutting or other suitable means and reset in their ideal locations in a model. Next, an arch wire is formed so as to fit the brackets of the ideal model and upon its completion this arch wire is removed and attached to the brackets on the teeth in the patient's mouth, the memory of the wire will apply the desired pressure to the teeth in the mouth to cause them to rotate or tip or otherwise move as desired towards the ideal location. It may be preferred to start the treatment with a wire applying only a small amount of force and to increase the force applied as the treatment continues by changing the wire. In any case, the orthodontist can go back to his ideal model for forming the arch wire which is to be positioned in the patient's mouth.
While the technique described herein will work with almost any bracket, this technique has been previously described with reference to a bracket of my design in U.S. Pat. No. 3,578,744 to A. J. Wildman, the disclosure of which is hereby incorporated by reference.
Because of the simplicity of the model making method described herein, the arch wires may be mounted on the lingual side of the teeth as well as the labial side, as presently done. This is possible because brackets may be secured directly to teeth without bands. Thus, for cosmetic reasons, or otherwise, it may be desired to mount a lingual arch wire.
In order to mount brackets to the lingual side of the teeth, the brackets are preferably mounted on the teeth without bands. Two methods for doing this are as follows:
In the first method, brackets are adhesively mounted on the patient's teeth and the brackets are covered with elastomeric caps. An impression is then taken of teeth with the brackets covered. The mounted covers are then removed from the teeth and are discarded.
Next, a replica of each tooth is made or obtained, as by casting, and a bracket is mounted on each replica in the space provided by the caps. The replicas are then placed in ideal positions simulating an ideal position for all the teeth relative to each other and an ideal arch wire is formed. The ideal arch wire is then removed from the ideal model and mounted in the brackets on the patient's teeth.
In the second method, an impression of a patient's teeth is made, which is duplicated in investment, a heat resistant material used in dental castings. Next, a thin layer of wax is placed on the back sides of the duplicate teeth so that a wax shell is formed thereon. Then wax replicas of the desired brackets are placed on the wax shell at locations corresponding to desired locations on the actual teeth. Next thin wax tubes are radially connected from each wax bracket to an upward sprue, and above that is connected a reservoir. The whole assembly is placed in a crucible and the plenum of the crucible filled with investment so that no empty space exists, except in the tubes. Next the wax is dissolved and molten metal, i.e., bracket and base material, is poured in. The hot investment is quenched in water, causing it to shatter, leaving brackets mounted on bases which fit onto individual teeth on the lingual side thereof. The brackets and bases are cleaned, as by sandblasting, so that no mark left by the tubes is apparent. The individual bases and brackets are then separated. The individual bases have a contour matching the shape of each tooth, with each base extending from one side of the back of a tooth to the other side so that each base indexes the position of the corresponding bracket on one tooth.
The individual teeth of the original impression are now separated with the new base and bracket castings temporarily mounted on each one. The teeth are then placed in ideal positions relative to each other, forming an ideal model, and an ideal arch wire is formed using the brackets thereon. Next each bracket integrally connected to a custom fitting base, is mounted on a corresponding tooth of a patient and the ideal arch wire is mounted thereon.
In summary, the method disclosed herein includes the steps of affixing brackets to the teeth of a patient. The brackets are of a conventional type for holding arch wires. Next an impression is made of the teeth with brackets thereon. The impression is then used in setting up a simulation or model of an ideal position for the teeth. One way to set up such an ideal model is to insert replicas of the brackets into the impression and cast a replica of each tooth and bracket, then separate the castings and mount the teeth to form a model. Another way to accomplish the same thing is to position brackets on a tooth simulator corresponding to the position brackets have been mounted on the patient's teeth. In either instance, the position of the brackets on the patient's teeth is used in the model process thereby overcoming the prior art problem of attempting to fix the brackets to the teeth after the arch wire is formed.
The next step involves removing the arch wire or wires from the model and attaching the arch wires to the brackets on the teeth in a patient's mouth. The arch wire or wires then urge the patient's teeth to their ideal position.
One advantage of the present method is that it will greatly simplify the practice of orthodontic dentistry in the following manner. A practitioner will mount brackets directly on a patient's teeth and make an impression. He can then send the impression to a laboratory where precision arch wires are formed. The laboratory will use the impression to make an ideal model by simulating ideal positions for the patient's teeth and the position of brackets thereon. The bracket position is known exactly relative to the tooth because the impression gives the exact position. Thus, the arch wire or wires formed in the laboratory will correspond to the ideal positions determined in the laboratory.