Dentistry – Orthodontics – Method of positioning or aligning teeth
Reexamination Certificate
1999-07-23
2001-01-16
Manahan, Todd E. (Department: 3732)
Dentistry
Orthodontics
Method of positioning or aligning teeth
Reexamination Certificate
active
06174163
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a bracket fitting method of an orthodontic appliance to be used for correcting teeth.
BACKGROUND OF THE ART
The orthodontic appliance is fitted by bonding its bracket to the tongue side face of a tooth of a patient. Since the tongue side face of the tooth has a more complicated shape than that of a lip side face, it is difficult to bond the bracket to an ideal position.
In order to bond the bracket to the ideal position on the tongue side face of the tooth, there has been adopted an indirect bonding method using the T.A.R.G. (Torque Angulation Reference Guide) or the C.L.A.S.S. (Custom Lingual Appliance Setup System). When the bracket is to be bonded to the tooth of the patient, according to that method, three to six teeth are individually bonded by using a bracket fitting core (or indirect tray) made of a flexible member such as silicone.
In the C.L.A.S.S., on the other hand, there is used a set-up tooth impression in which the tooth impression of the patient is re-arrayed into a target state, so that the bracket can be positioned more correctly than the T.A.R.G. This set-up tooth impression is prepared by forming a duplicate mold from the original impression mold of the tooth impression of the patient and by dividing the duplicate mold into individual teeth to re-array them.
In order to form the indirect tray by using the set-up tooth impression, the bracket is positioned at first with respect to the set-up tooth impression by using a gauge or the like, and the gap between the positioned bracket and the mold is filled with an adhesive (or an advance adhesive). As a result, the base face of the bracket is formed to conform to the tongue side face intrinsic to each tooth (advance of bracket). Next, the bracket positioned with respect to the set-up tooth impression is returned to the original impression mold, and the indirect tray is formed by covering the original impression mold with the silicone.
The indirect tray over all the teeth is usually divided into those for three to six teeth. Then, the adhesive is applied to the base face of the advanced bracket, and the indirect tray is fitted to the teeth of the patient, so that the bracket is bonded to the teeth of the patient. Finally, the indirect tray is removed from the bracket.
However, the indirect tray of the prior art has the following problems.
First of all, in both the T.A.R.G. and the C.L.A.S.S., the indirect tray extends over the three to six teeth and has flexibility so that it is liable to distort. This may cause a displacement of the bracket when this bracket is fitted to the teeth of the patient.
At the fitting time, on the other hand, the tray may distort to float the base of the bracket from the teeth of the patient. This makes it necessary to apply more adhesive to ensure the adhesion and fitting. If much adhesive is applied to the bracket, however, the excess adhesive will exude from the fitting face. This makes a work necessary for removing the excess adhesive.
Since the indirect tray of the prior art has a size to extend over the three to six teeth, moreover, it has to be supported till the adhesive sets after it was fitted to the teeth of the patient, so that it may go out of position.
Since the indirect tray of the prior art samples not only the tooth shape of the patient but also the alignment of teeth, still moreover, it cannot be used if the tooth alignment of the patient changes after the sampling of the tooth impression of the patient and before the fitting of the bracket. For this time period, therefore, it is impossible to extract or separate the tooth.
Next, according to the method using the C.L.A.S.S., the bracket has to be returned to the original impression mold after it was advanced with the set-up tooth impression. Since the original impression mold has to be left as it is, therefore, a duplicate is required for forming the set-up to the impression.
In order to return the bracket to the original impression mold, on the other hand, complicated technical works are required for making a person tray or for forming a notch or mark in the original impression mold. With these troubles, the bracket may goes out of position when it is returned to the original impression mold.
DISCLOSURE OF THE INVENTION
In order to solve the aforementioned problems, an object of the invention is to provide a bracket fitting method and a bracket fitting core of an orthodontic appliance which is enabled to position correctly by fitting a bracket for each tooth.
According to the invention, there is provided an orthodontic bracket fitting method of an orthodontic appliance for correcting each tooth of a patient by fitting the base of an orthodontic bracket individually to the tooth and by extending an orthodontic wire between the orthodontic brackets. First of all, the orthodontic brackets are individually positioned to the individual tooth of the impression mold of the patient. Next, each tooth of the impression mold is with a resin in an unset state, to form individually for each tooth a bracket fitting individual resin core which is integrally molded of an advance portion packed between the tooth and the base of said bracket positioned with respect to said tooth, and a core portion extending from said advance portion to a cut edge of the tooth or an occlusal surface. Then, said bracket fitting individual resin core in the state integrated with said bracket is taken out from each tooth of said impression mold and is fitted and bonded to each corresponding tooth of the patient. Finally, each bracket fitting individual resin core is removed.
In the invention, the individual resin core is used as the bracket fitting core. This individual resin core is formed of a resin having little flexibility for each tooth so that no distortion occurs when it is fitted to the tooth of the patient. As a result, the bracket can be correctly positioned on the tooth of the patient.
Since no distortion occurs, on the other hand, the advance portion for the fitting face does not flat from the tooth of the patient. As a result, the bonding can be ensured with a small amount of adhesive so that the exudation of the adhesive is eliminated to make it unnecessary to remove the excess adhesive.
Since this individual resin core is formed individually for each tooth, it is simply shaped to cover the bracket fitting face of the tooth and the cut edge of the tooth or an occlusal surface so that it can be taken out without any breakage from the mold even if it has little flexibility.
On the other hand, the individual resin core is small and light because it is formed individually for each tooth. This makes it unnecessary to support the individual resin core till the adhesive is set after it was fitted to the tooth of the patient.
Since the individual resin core samples the shape of each tooth of the patient and has no relation to the alignment of teeth of the patient, moreover, it can be fitted even if the alignment of teeth of the patient changes for the time period from the sampling of the tooth impression of the patient to the fitting of the bracket. For this time period, therefore, a treatment such as a tooth extraction or separation can be made.
When this individual resin core is formed using the C.L.A.S.S., on the other hand, the alignment of teeth has no relation so that the bracket need not be returned to the original impression mold after the bracket was advanced with the set-up tooth impression. This makes it possible to eliminate the technical work which might otherwise be required for making a personal tray or for forming a notch or mark in the original impression mold. On other hand, there arises no problem of the positional displacement which might otherwise occurs when the bracket is returned to the original impression mold.
Thus, the duplicate mold can be eliminated, said impression mold can be exemplified by a set-up tooth impression which is prepared by dividing the original impression mold of the patient for each tooth and by re-arraying it to a target alignment of teeth.
On the other
Burns Doane Swecker & Mathis L.L.P.
Manahan Todd #E.
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