Dentistry – Orthodontics – By device having means to apply outwardly directed force
Reexamination Certificate
2000-09-15
2002-01-01
Wilson, John J. (Department: 3732)
Dentistry
Orthodontics
By device having means to apply outwardly directed force
C433S019000
Reexamination Certificate
active
06334771
ABSTRACT:
1. FIELD OF THE INVENTION
This invention relates to a palatal expander and particularly a dual-joint palatal expander to expand upper jaw bone effectively and quickly for accommodating and aligning the front teeth of a patient.
2. BACKGROUND OF THE INVENTION
Because of oral disorder or disease, there are cases in which patients, particularly children of young age, need surgical or plastic operation to cut through the palatal or upper jaw bone and gum. After surgical operation, the upper jaw bone need to be expanded for accommodating and aligning the front teeth. Hence a palatal expander is usually employed to expand the upper jaw bone sideward and forward to create more space for the front teeth to grow and align properly.
FIG
1
shows a conventional palatal expander
6
which is also known as jackscrew mounted in the upper jaw of the patient. It has a pair of spaced anchor blocks
62
which have respectively an opposite internal screw bore engageable with a screw bar
64
. The anchor blocks
62
are slidable movable along two spaced guide rods
63
which run through the anchor blocks
62
. Each anchor block
62
has one side attached to a pair of brackets
61
which have one end fastened to a first upper barrel band
11
and a second upper barrel band
21
. The first and second barrel bands
11
and
21
are mounted respectively on a molar
1
and a premolar
2
. There is a wire anchor
30
on each barrel band and a steel wire
3
to fasten the first and second barrel bands
11
and
21
together. Turning a screw head
641
located between the anchor blocks
62
, the screw bar
64
will be turned and drives the anchor blocks
62
away from each other. The brackets
61
will then push the barrel bands
11
and
21
of two sides away from each other. As the molar
1
and premolar
2
have relatively strong root deeply planted in the upper jaw bone, the upper jaw bone will be stretched and expanded.
FIG. 2
shows what is actually happening when using the jackscrew
6
shown in FIG.
1
. The upper jaw bone at the front teeth position will be stretched in two opposite directions A and B sideward and slightly backward against a center O and forming a fan angle &agr;. The stretch direction A and B is not linear. Instead of expanding the upper jaw bone sideward and forward, the upper jaw bone will be expanded sideward but crowed backward. The direction of front teeth expansion is unpredictable. This will cause the misalignment of the front teeth. Then an orthodontic treatment is needed to align the front teeth. This adds more pain and trouble to the patients.
FIG
3
shows another conventional palatal expander
6
′ also known as a fan-type jackscrew. The operation principle is generally same as the one shown in FIG.
1
. However instead of a pair of anchor blocks
62
and guide rods
63
, a pair of rocker arms
65
are used to engage with the screw bar
64
′. Each rocker arm
65
has a screw end
642
engaged with the screw bar
64
′ and a pivotal center
66
engaged with another rocker arm
65
. Turning the screw head
641
′, the screw bar
64
′ will turn and drive the screw end
642
away from each other. Then the rocker arms
65
will be expanded to a wider angle about the pivotal center
66
to move the bracket
61
to push the barrel bands
11
and
21
. As a result, the upper jaw bone may also be expanded. The expanding direction A′ and B′ (shown in
FIG. 4
) is also being stretched slightly backward against a center O′ and forming a fan angle &agr;′. It also has similar disadvantage shown in the
FIG. 1
example.
Furthermore the prior arts set forth above are difficult to install and use. It is particularly troublesome for children who generally have not much patience to endure such an ordeal for a long period of time. Most children have great resistance to take this long and painful treatment. Even to those children who take this treatment, the effectiveness will be compromised when proper adjustment is not performed regularly. The treatment takes long time and great cost. All this begs for improvement.
SUMMARY OF THE INVENTION
It is an object of this invention to provide a rapid palatal expander that is able to expand upper jaw bone of a patient sideward and forward almost linearly so that the upper jaw bone will be stretched horizontally and forward to accommodate the front teeth and growing alignment.
It is another object of this invention to provide a rapid palatal expander that can expand upper jaw bone of a patient effectively and quickly so that total treatment time may be shortened to relieve patient's trouble and inconvenience and to reduce expense.
It is a further object of this invention to provide a rapid palatal expander that has a constant expansion feature that enables the upper jaw bone of a patient be stretched as desired constantly and automatically without patient's active involvement or extra efforts. It may further speed up total treatment time and save medical expense.
In one aspect, the palatal expander according to this invention includes a dual-joint fan-type jackscrew. A pair of rocker arms each has one end respectively engaged with a fulcrum and another end engageable with a screw bar. Turning the screw bar, the rocker arms will be moved away sideward in opposite direction to stretch the upper jaw bone sideward and forward. The two fulcrums may be spaced from each other to enable the sideward movement of the rocker arms become almost a linear path. The backward stretching that happened to a single joint fan-type jackscrew thus may be minimized.
In another aspect, this invention provides an elastic means which has two ends engageable with molars of the upper and lower jaw. When patients mouth is closed, the elastic means will be compressed by the upper and lower jaw and produces a forward force to push the upper jaw bone forward.
This may be done without patient's additional effort, during day time and even in sleep. The jaw bone expanding effect is thus greatly enhanced. It may further shorten total treatment time and may also save the patient a lot of trouble and medical expense.
REFERENCES:
patent: 4348179 (1982-09-01), Nardella
patent: 5645423 (1997-07-01), Collins, Jr.
patent: 5775898 (1998-07-01), Schellino et al.
patent: 5964588 (1999-10-01), Cleary
patent: 5975894 (1999-11-01), Pozzi
Dougherty & Troxell
Wilson John J.
LandOfFree
Rapid palatal expander does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Rapid palatal expander, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Rapid palatal expander will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2854146