US3391461A - Convertible buccal tube and bracket - Google Patents

Description

July 9, 1968 w. JOHNSON 3,391,461

CONVERTIBLE BUCCAL TUBE AND BRACKET Filed Oct. 23, 1965 2 Sheets-Sheet 1 Z INVENTOR.

y 9, 1968 F. w. JOHNSON 3,391,451

CONVERTIBLE BUCCAL TUBE AND BRACKET Filed Oct. 23, 1965 2 Sheets-Sheet 2 INVENTOR. @m/x Jim/mu United States Patent Oflice 3,391,461 Patented July 9, 1968 3,391,461 CONVERTIBLE BUCCAL TUBE AND BRACKET Frank W. Johnson, Monrovia, Calif., assignor to Unitek Corporation, Monrovia, Califl, a corporation of California Filed Oct. 23, 1965, Ser. No. 503,307 1 Claim. (CI. 32-14) ABSTRACT OF THE DISCLOSURE An orthodontic bracket assembly having a removable cap which covers an arch-wire slot in an orthodontic bracket. The cap has bendable tabs which are folded over the bracket to secure the cap in place, and further has a tab or hook to anchor one end of an elastic band. A buccal tube is secured to the cap, and the cap and tube are removable as a unit to convert the assembly to a conventional bracket for use in latter stages of orthodontic treatment.

Background of the invention An orthodontic treatment program involves the application of mechanical force to teeth which are to be repositioned in the dental arch of the patient. The corrective force is commonly applied by a tensioned or torqued arch wire which extends around the dental arch to be secured to orthodontic brackets mounted on individual teeth.

Each bracket is slotted to receive the arch wire, and includes a pair of overhanging tie wings forming a cleat around which a ligature or tie wire is fastened to secure the arch wire in the slot. The bracket is welded to a tooth band which is in turn cemented to a tooth.

The ends of the arch wire are anchored at each end of the dental arch in a buccal tube. The buccal tube is secured to a tooth band which is cemented to a terminal or anchor tooth.

The band on the anchor tooth may also carry additional orthodontic fixtures. For example, a face-bow tube may be mounted on this band to provide an anchoring socket for a conventional face bow. A hook may also be secured to this tooth band to anchor one end of an orthodontic elastic band.

The anchor teeth are typically the rearmost molars in the dental arch. As orthodontic treatment is usually begun at an early age, the first or six year molars normally serve as the anchor teeth during at least the initial treatment stage.

The second molars, which normally grow in or erupt around age twelve, may be used as anchor teeth for later stages of the treatment program. Thus, the dentist may begin the orthodontic program using the first molars as anchor teeth, and plan to use the second molars as anchor teeth after they erupt.

In such a case, the practice in the past has been to cement tooth bands carrying the desired anchoring fixtures to the first molars during the initial state of treatment. When the second molars erupt, a new set of tooth bands and anchoring fixtures are cemented to them.

It is then often desirable to apply corrective force (to correct, for example, a crossbite condition) to the first molars which are no longer needed as anchor teeth. The anchoring fixtures already in place on the first molars do not provide the desired open slot and tie wings to accommodate the arch wire. The fixtures and the associated tooth bands must therefore be removed from the first molars and replaced by new tooth bands on which are mounted conventonal arch-wire-receiving brackets.

This conversion process is both time consuming for the dentist and uncomfortable for the patient. Typically, approximately one-half hour of chair time is required to remove the old anchoring fixtures and tooth bands, and to install new brackets and tooth bands on the first molars. The molars are in a relatively inaccessible position in the patients mouth, and the conversion process is awkward for both dentist and patient.

Attempts have been made in the past to avoid the replacement of first-molar bands and fixtures by initially installing a bracket which has a plate welded across the bracket slot to form a buccal tube. The plate is ground off in the patients mouth when the second molars are established as anchor teeth. Unfortunately, the required grinding can be as time consuming as replacing the entire band and bracket, and is very uncomfortable for the patient.

The convertible buccal tube and bracket of this invention overcomes the difiiculties just described. A tooth band carrying a conventional orthodontic bracket is cemented to the first molar at the beginning of the treatment program. A cap is installed over the bracket, covering the arch-wire slot to form a buccal tube. The cap slides over the bracket in engagement with the bracket tie wings, and is secured in place by bending tabs on the cap against the bracket. The cap may also be equipped with a face-bow tube, and a hook for an elastic band.

When the second molars grow, in new tooth bands and anchoring fixtures are installed on them. The caps are then removed from the brackets on the first molars whereby a conventional bracket is made available to accept the arch wire. The conversion of the appliance on the first molars can be accomplished very quickly with little or no discomfort, and the expense of new bands and brackets for these teeth is avoided.

Briefly stated, the invention comprises an orthodontic bracket having a lingual surface adapted to be secured to a tooth band, a buccal surface having a slot to receive an arch wire, and a pair of overhanging wings on opposite lateral edges of the bracket and extending toward the tooth band to define a pair of generally V-shaped notches opening toward the tooth band and adapted to retain a tie-wire used to secure the arch wire in the slot; and a removable cap having a body portion adapted to fix over the buccal surface of the bracket to cover at least a portion of the slot. A pair of retaining flanges are integrally formed on opposite lateral edges of the body portion. The flanges extend first rearwardly over the wings toward the tooth band, and then inwardly behind the wings toward each other and toward the V-shaped notches whereby the cap is slidably engageable with the bracket.

In a preferred form, the cap includes bendable tabs extending from the mesial and distal ends of the body portion for locking the cap to the bracket. The distal end of the body portion may further have a distally extending hook to anchor an elastic band. Preferably, the body portion which overlies the slot is bulged outwardly away from the slot to provide clearance for the arch wire. In another form, a face-bow tube is secured to the cap body to anchor the end of a conventional face bow.

These and other aspects of the invention will be described in detail with reference to the attached drawings, in which:

FIG. 1 is a perspective view of a conventional orthodontic bracket as used in the invention;

FIG. 2 is a perspective view of a cap adapted for sliding engagement with the bracket;

FIG. 3 is a perspective view of the assembled bracket and cap, showing a face-bow tube secured to the cap;

FIG. 4 is a perspective view of the bracket and cap secured to a tooth band on a first molar tooth and engaged with an arch wire; and

FIG. 5 is a perspective view of the bracket shown in FIG. 4 with the cap removed, and a second molar serving as an anchor tooth.

Referring to FIG. 1, a conventional orthodontic bracket has a base 12, the rear or lingual surface 13 of which is adapted to be secured to a tooth band. The bracket has an outwardly extending main body 15 secured to the base and having a buccal surface 16. The buccal surface has a slot 18 into the main body to receive a conventional arch wire. A pair of overhanging wings 20 are integrally formed on opposite lateral edges of the bracket main body, and extend rearwardly to define a pair of generally V- shaped notches 21.

This type of bracket has received widespread acceptance by Orthodontists and has been in use for many years. It is a feature of this invention that a conventional and generally accepted bracket may be used to provide the ordinary functions of a bracket, as Well as temporarily serving as part of a buccal-tube fixture.

The improvement of this invention is shown in FIG. 2, and comprises a cap 24 which is arranged to be slidably engagable with bracket 10. The cap has a body portion 25 formed to fit snugly over the buccal surface of the bracket, whereby at least a portion of the bracket slot is covered. A pair of retaining flanges 26 are integrally formed on opposite lateral edges of the body portion. The flanges extend first rearwardly and then inwardly toward each other to dovetail with the cleat-like bracket wings. The body portion has a mesial end 28 and a distal end 29. A pair of bendable tabs 31 extend from the mesial and distal ends.

Preferably, a center area 33 of the body portion which overlies the slot is bulged outwardly to provide clearance for an arch wire which may extend slightly above the buccal surface of the bracket when fitted in the slot. A distally extending tab 35 is secured to the distal end of the body-portion center area to serve as an anchor for an orthodontic elastic band.

FIG. 3 illustrates the assembled cap and bracket, and shows an alternative form of cap 24 which includes a face-bow tube 37. The face-bow tube is positioned on the surface of the cap body portion adjacent the bulged center area, and preferably is secured to the cap by spot Welding. Preferably, a fillet 38 of silver solder is formed along the junction of the face-bow tube and cap to avoid a crevice which might otherwise trap food particles when the bracket and cap are mounted in the patients mouth.

To install the cap on the bracket, the cap is slipped sideways over the bracket, with cap retaining flanges 26 in engagement with bracket wings 20. Cap tabs 31 are then bent against the bracket body as shown in FIG. 3, locking the cap securely in place. The cap closes the open side of the bracket slot to form a buccal tube '39.

FIG. 4 shows the convertible buccal tube and bracket of this invention installed in a patients mouth having a second bicuspid 41 and a first molar 42. The first molar is serving as an anchor tooth, and a second molar 43 is just beginning to erupt through the patients gum.

A conventional bracket and tooth-band assembly 45 are cemented to the second bicuspid. Cap 24 is assembled on bracket 10 welded to a tooth band 46 which is cemented to the first molar. An arch wire 48 extends around the dental arch and is secured to assembly 45 by a con- 4 ventional tie wire 49. The end of the arch wire extends through buccal tube 39 formed by cap 24 and bracket 10 In FIG. 5, second molar 43 has grown in and is adapted as an anchor tooth by installation of a conventional tooth-band assembly 52 carrying a buccal tube and facebow tube. The cap has been removed from bracket 10 by straightening the cap tabs and sliding the cap off the bracket. A conventional bracket is thereby made available on the 'first molar, and the arch wire is secured in place in the bracket slot by a tie wire 54.

There has been described a convertible buccal tube and bracket which provides a buccal tube on the first molars during the early stages of an orthodontic treatment program. When the dentist desires to use the second molars as anchor teeth, the first molars are quickly and easily provided with a conventional orthodontic bracket by simply removing the cap of this invention. Patient discomfort is minimized, and a substantial saving in chair time for dentist and patient is made possible. The cap has been illustrated in combination with a conventional edgewise bracket, but it is to be understood that it is also usable with multiphase brackets or other bracket types having the general characteristics described above.

I claim:

1. In combination with an orthodontic bracket having a lingual surface adapted to be secured to a tooth band, a buccal surface having a slot to receive an arch wire, and a pair of overhanging wings on opposite lateral edges of the bracket and extending toward the tooth band to define a pair of generally V-shaped notches opening toward the tooth band and adapted to retain a tie wire used to secure the arch wire in the slot, the improvement comprising a removable cap having a body portion adapted to fit over the buccal surface of the bracket to cover at least a portion of the slot, the body portion having mesial and distal ends, each end having a tab which is bendable rearwardly toward the tooth band to lock the cap to the bracket, the distal end further having a distally extending hook to anchor an elastic band, the body portion overlying the slot being bulged outwardly away from the slot to provide clearance for the arch wire, a pair of retaining flanges integrally formed on opposite lateral edges of the body portion, the flanges extending first rearwardly over the wings toward the tooth band and then inwardly behind the wings toward each other and toward the V-shaped notches whereby the cap is slidably engagable with the bracket, and a face bow tube secured to the body portion.

References Cited UNITED STATES PATENTS 1,369,665 2/1921 Johnson 32-14 3,091,857 6/ 1963 Rubin 32-14 3,128,552 4/1964 Broussard 3214 3,256,602 6/1966 Broussard 3214 OTHER REFERENCES ORMCO publication, figure represented by catalog number 150.

LOUIS G. MANCHENE, Primary Examiner. N. RUSHE'FSKY, Assistant Examiner.

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