Dentistry – Orthodontics – Tool
Reexamination Certificate
1999-12-27
2001-01-16
Wilson, John J. (Department: 3732)
Dentistry
Orthodontics
Tool
C433S141000
Reexamination Certificate
active
06174162
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to the field of orthodontic expanders of the type which are placed in a patient's mouth and engage teeth on opposing sides of the palate. The expander is then forced apart by means of a double-threaded shaft called a retention or expansion screw to exert a lateral force on the palate to expand it. In particular, the present invention is directed to an improved hand-held and hand-activated device for torquing the expansion screw of an orthodontic expander appliance.
BACKGROUND OF THE INVENTION
There are various held-held and manually operated devices for adjusting an orthodontic expander by turning or torquing the double-threaded expansion screw. All of these devices suffer from one or more disadvantages.
One disadvantage of some prior art devices results from the fact that the torquing device itself is small enough to fit entirely within the patient's mouth. This has a primary disadvantage of blocking off the dentist's view because the hand holding and operating the torquing device covers the patient's mouth, making it difficult to insert the device in the expansion screw. Secondly, the torquing device is so small that if the dentist inadvertently drops the device while it is in a patient's mouth, it could possibly be swallowed or cause discomfort to the patient since the patient is normally positioned with his or her mouth opening upwardly. Thus, the torquing device is typically placed on a tether for safety and comfort, making manipulation of the device even more cumbersome.
Many prior art devices which are capable of torquing an expansion screw are easily dislodged from the screw, either because it is difficult accurately to use the device through a full 90° rotation of the screw as is required, or, as is equally common, while effecting a full quarter turn rotation of the expansion screw, the activating tip may slide out of the aperture in the center of the expansion screw in which the tip is received. In the case of an adjusting device becoming dislodged from the expansion screw while the dentist is turning the device, the pointed tip of the activating device has the potential to poke or scratch the tissue of the patient's mouth, causing discomfort or pain. Dentists, as well as patients, of course, are desirous of eliminating such discomfort.
Another disadvantage of some prior art devices is that they are difficult to operate in the sense that because of the structure of the device, the dentist's hand holding the device partially or substantially occludes the opening of the mouth. This restricts the amount of light that might enter the patient's mouth to illuminate the expander and adjusting mechanism, thereby rendering it more difficult to make an adjustment. Manipulating the small tool with the hand also restricts the field of vision of the dentist inside the patient's mouth.
These disadvantages are overcome by the improved device of the present invention.
SUMMARY OF THE INVENTION
The present invention provides a dental instrument capable of torquing the double-threaded expansion screw of a conventional orthodontic expander appliance with an integral device having an elongated handle and an angled activator tip. The activator tip is in the form of a wire-like extension, and it defines an angle with the axis of the handle which is either approximately 90° or slightly greater.
The length of the handle is such that the dentist may comfortably grasp the handle with his or her hand completely outside of the mouth and to the side of the mouth so that the dentist's view is not occluded. That is, the length of the handle and the angle at which the tip is directed relative to the axis or extension of the handle, are such that the hand of the dentist holding the instrument is to the side of the patient's mouth while adjusting the expander; and the dentist's hand is completely to the side of the medial plane of the patient's mouth. As used herein, the “medial plane” is a plane passing through the center of the patient's mouth and bisecting the patient's palate. Thus, when the patient is standing upright or looking in a vertical direction, the medial plane is also vertical, as is the case, normally, when a dentist is adjusting an orthodontic expander appliance.
Due to the construction of the inventive instrument, the activating tip is easily inserted in the torquing apertures of the expansion screw, the view of the user is largely unobstructed, and the user may exert more force to torque the screw than with prior devices without fear of dislodging the torquing device from the expansion screw.
Other features and advantages of the present invention include the fact that the instrument is constructed similar to a typical dental instrument having an extended handle of the type commonly employed by dentists and orthodontists for other appliances so it is more familiar to most dentists. Moreover, the new instrument can be made of more permanent metal which enables the dentist to sterilize and re-use the instrument, or it can be made of plastic as a disposable instrument, so that it can be used by the patient or associate of the patient having knowledge of what is required to be done, and then the instrument may be disposed of after use. Of primary benefit is the ease with which the user of the instrument, whether dentist or layman, can position the tip into the center torquing hole of the expansion screw of an expander appliance without obstructing his or her vision of the appliance. This greatly reduces the tendency to miss the hole in the expansion screw and perhaps poke the palate tissue of the patient. Moreover, once the instrument is properly seated in the expansion screw, the dentist or other user may place his or her index finger onto the shaft of the instrument, adjacent the handle, and thereby apply greater leverage in rotating the expansion screw to expand the appliance while maintaining a firm grip on the instrument and assuring that the instrument remains properly seated in the expansion screw during an adjustment procedure.
Other features and advantages of the present invention will be apparent to persons skilled in the art from the following detailed description of a preferred embodiment accompanied by the attached drawing wherein identical reference numerals will refer to like parts in the various views.
REFERENCES:
patent: 4280808 (1981-07-01), Johnsen et al.
patent: 4483674 (1984-11-01), Schutz
patent: 5133659 (1992-07-01), Shilliday
patent: 5423677 (1995-06-01), Brattesani
patent: 5904479 (1999-05-01), Staples
American Tooth Industries
Emrich & -Dithmar
Wilson John J.
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