U.S. patent application number 09/851819 was filed with the patent office on 2002-03-14 for computerized system and method for correcting tooth-size discrepancies.
Invention is credited to Hamilton, David C..
Application Number | 20020031742 09/851819 |
Document ID | / |
Family ID | 23733031 |
Filed Date | 2002-03-14 |
United States Patent
Application |
20020031742 |
Kind Code |
A1 |
Hamilton, David C. |
March 14, 2002 |
Computerized system and method for correcting tooth-size
discrepancies
Abstract
A computerized system and method for diagnosing a tooth-size
discrepancy and recommending an ideal arch size based on the size
of an individual patient's teeth. The computerized system includes
a central processing unit, a first storage device, a second storage
device, a dynamic memory device, and input/output devices. The
input devices include a computerized caliper for measuring the
mesiodistal width of teeth and directly inputting the measurements
into the computerized system. The computerized system and method
determine the existence of a tooth-size discrepancy, the necessary
anatomical correction, at least one tooth responsible for the
tooth-size discrepancy, and a recommended arch wire size.
Inventors: |
Hamilton, David C.; (New
Castle, PA) |
Correspondence
Address: |
KENYON & KENYON
One Broadway
New York
NY
10004
US
|
Family ID: |
23733031 |
Appl. No.: |
09/851819 |
Filed: |
May 9, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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09851819 |
May 9, 2001 |
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09436588 |
Nov 9, 1999 |
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Current U.S.
Class: |
433/20 ;
705/1.1 |
Current CPC
Class: |
A61C 7/002 20130101;
A61C 7/00 20130101; A61C 19/04 20130101 |
Class at
Publication: |
433/20 ;
705/1 |
International
Class: |
A61C 003/00; G06F
017/60 |
Claims
What is claimed is:
1. A system for selecting at least one arch wire, comprising: an
input device inputting at least one of: i) at least one sum of a
plurality of tooth sizes, and ii) a plurality of tooth sizes, a
processor, the input device being interfaced to the processor and
the processor receiving from the input device the at least one of
i) the at least one sum, and ii) the plurality of tooth sizes, if
the processor receives the plurality of tooth sizes from the input
device, the processor determines the at least one sum as a function
of the plurality of tooth sizes, the processor selecting at least
one arch wire as a function of the at least one sum; and a display
device displaying the selected at least one arch wire.
2. The system according to claim 1, wherein the input device is a
digital caliper.
3. The system according to claim 2, wherein the at least one sum
includes a sum of tooth sizes of a maxillary arch and a sum of
tooth sizes of a mandibular arch, the processor determines at least
one of an anatomical correction in the maxillary arch and an
anatomical correction in the mandibular arch as a function of the
sum of tooth sizes of the maxillary arch and the sum of tooth sizes
of the mandibular arch, and the display device displays the at
least one of the anatomical correction in the maxillary arch and
the anatomical correction in the mandibular arch.
4. The system according to claim 3, wherein the processor
determines the anatomical correction in the maxillary arch using
the following formula: X=L/R-U, wherein, X is the anatomical
correction in the maxillary arch, L is the sum of the tooth sizes
of the mandibular arch, R is a ratio, and U is the sum of the tooth
sizes of the maxillary arch.
5. The system according to claim 4, wherein the ratio is one of
0.772 for a six-tooth analysis and 0.913 for a twelve-tooth
analysis.
6. The system according to claim 3, wherein the processor
determines the anatomical correction in the mandibular arch using
the following formula: Y=(U.times.R)-L, wherein, Y is the
anatomical correction in the mandibular arch, U is the sum of the
tooth sizes of the maxillary arch, R is a ratio, and L is the sum
of the tooth sizes of the mandibular arch.
7. The system according to claim 6, wherein the ratio is one of
0.772 for a six-tooth analysis and 0.913 for twelve-tooth
analysis.
8. The system according to claim 1, wherein at least one sum
includes a sum of tooth sizes of a maxillary arch and a sum of
tooth sizes of a mandibular arch, and wherein the selected at least
one arch wire includes an arch wire for the maxillary arch and an
arch wire for the mandibular arch.
9. The system according to claim 8, wherein if the sum of tooth
sizes of the maxillary arch is less than or equal to 44.5 mm, the
arch wire selected for the maxillary arch has a radius of curvature
of approximately 25.4125 mm and the arch wire selected for the
mandibular arch has a radius of curvature of approximately 23.0375
mm.
10. The system according to claim 8, wherein if the sum of tooth
sizes of the maxillary arch is between 44.5 mm and 49.4 mm, the
arch wire selected for the maxillary arch has a radius of curvature
of approximately 26.75 mm and the arch wire selected for the
mandibular arch has a radius of curvature of approximately 24.25
mm.
11. The system according to claim 8, wherein if the sum of tooth
sizes of the maxillary arch is at least 48.4 mm, the arch wire
selected for the maxillary arch has a radius of curvature of
approximately 28.0875 mm and the arch wire selected for the
mandibular arch has a radius of curvature of 25.4625 mm.
12. The system according to claim 1, wherein the input device is a
keyboard.
13. A system for determining an anatomical correction for at least
one of a maxillary arch and a mandibular arch, comprising: a
caliper for measuring at least one tooth size; a processor, the
caliper being interfaced to the processor, the processor receiving
from the caliper the at least one tooth size, the processor
determining at least one sum of a plurality of tooth sizes as a
function of the least one tooth size, the processor determining the
anatomical correction for the at least one of the maxillary arch
and the mandibular arch as a function of the least one sum; and a
display device displaying the determined anatomical correction.
14. The system according to claim 13, wherein the at least one sum
includes a sum of tooth sizes of the maxillary arch and a sum of
tooth sizes of the mandibular arch, the processor determining the
anatomical correction for the at least one of the maxillary arch
and the mandibular arch as a function of the sum of tooth sizes of
the maxillary arch and the sum of tooth sizes of the mandibular
arch.
15. The system according to claim 13, wherein the processor
determines the anatomical correction in the maxillary arch using
the following formula: X=L/R-U wherein, X is the anatomical
correction in the maxillary arch, L is the sum of the tooth sizes
of the mandibular arch, R in the ratio, and U in the sum of the
tooth sizes of the maxillary arch.
16. The system according to claim 15, wherein the ratio is one of
0.772 for a six-tooth analysis and 0.913 for a twelve-tooth
analysis.
17. The system according to claim 13, wherein the processor
determines the anatomical correction in the mandibular arch using
the following formula: Y=(U.times.R)-L, wherein, Y is the
anatomical correction in the mandibular arch, U is the sum of the
tooth sizes of the maxillary arch, R is a ratio, and L is the sum
of the tooth sizes of the mandibular arch.
18. The system according to claim 17, wherein the ratio is one of
0.772 for a six-tooth analysis and 0.913 for a twelve-tooth
analysis.
19. A computerized method for selecting at least one arch wire,
comprising the steps of: receiving from an input device by a
processor at least one of: i) at least one sum of a plurality of
tooth sizes, and ii) a plurality of tooth sizes; if the plurality
of tooth sizes are received, determining by the processor the at
least one sum; and selecting by the processor the at least one arch
wire as a function of the at least one sum.
20. The computerized method according to claim 19 further
comprising the step of: displaying the selected at least one arch
wire.
21. The computerized system according to claim 19, wherein the
input device is a digital caliper.
22. The computerized method according to claim 19, wherein the at
least one sum includes a sum of tooth sizes of a maxillary arch and
sum of tooth sizes of a mandibular arch, further comprising the
steps of: determining by the processor at least one of an
anatomical correction in the maxillary arch and an anatomical
correction in the mandibular arch as a function of the sum of tooth
sizes of the maxillary arch and the sum of tooth sizes of the
mandibular arch; and displaying the at least one of the anatomical
correction in the maxillary arch and the anatomical correction in
the mandibular arch.
23. The computerized method according to claim 22, wherein the step
of determining the at least one of the anatomical correction in the
maxillary arch and the anatomical correction in the mandibular arch
includes a step of determining the anatomical correction in the
maxillary arch using the following formula: X=L/R-U, wherein, X is
the anatomical correction in the maxillary arch, L is the sum of
the tooth sizes of the mandibular arch, R is a ratio, and U is the
sum of the tooth sizes of the maxillary arch.
24. The computerized method according to claim 23, wherein the
ratio is one of 0.772 for a six-tooth analysis and 0.913 for a
twelve-tooth analysis.
25. The computerized method according to claim 22, wherein the step
of determining the at least one of the anatomical correction in the
maxillary arch and the anatomical correction in the mandibular arch
includes a step of determining the anatomical correction in the
mandibular arch using the following formula: Y=(U.times.R)-L,
wherein, Y is the anatomical correction in the mandibular arch, U
is the sum of the tooth sizes of the maxillary arch, R is a ratio,
and L is the sum of the tooth sizes of the mandibular arch.
26. The computerized method according to claim 25, wherein the
ratio is one of 0.772 for a six-tooth analysis and 0.913 for a
twelve-tooth analysis.
27. The computerized method according to claim 19, wherein the at
least one sum includes a sum of tooth sizes in a maxillary arch and
a sum of tooth sizes in a mandibular arch, wherein the selecting
step includes a step of: if the sum of the tooth sizes in the
maxillary arch is less than or equal to 44.5 mm, selecting an arch
wire for the maxillary arch having a radius of curvature of
approximately 25.4125 mm and selecting an arch wire for the
mandibular arch having a radius of curvature of approximately
23.0375 mm.
28. The computerized method according to claim 19, wherein the at
least one sum includes a sum of tooth sizes in a maxillary arch and
a sum of tooth sizes in a mandibular arch, wherein the selecting
step includes a step of: if the sum of tooth sizes of the maxillary
arch is between 44.5 mm and 49.4 mm, selecting an arch wire for the
maxillary arch having a radius of curvature of approximately 26.75
mm and selecting an arch wire for the mandibular arch having a
radius of curvature of approximately 24.25 mm.
29. The computerized method according to claim 19, wherein the at
least one sum includes a sum of tooth sizes in a maxillary arch and
a sum of tooth sizes in a mandibular arch, wherein the selecting
step includes a step of: if the sum of tooth sizes of the maxillary
arch is at least 48.4 mm, selecting an arch wire for the maxillary
arch having a radius of curvature of approximately 28.0875 mm and
selecting an arch wire for the mandibular arch having a radius of
curvature of 25.4625 mm.
30. The system according to claim 19, wherein the input device is a
keyboard.
31. A computerized method for determining an anatomical correction
for at least one of a maxillary arch and a mandibular arch,
comprising the steps of: measuring with a caliper a plurality of
tooth sizes; receiving by the processor from the caliper the at
least one of tooth size; determining by the processor the at least
one sum as a function of the plurality of tooth sizes; and
determining the anatomical correction for the at least one of the
maxillary arch and the mandibular arch as a function of the at
least one mesiodistal width; and displaying the determined
anatomical correction.
32. The computerized method according to claim 31, wherein the at
least one sum includes a sum of tooth sizes of a maxillary arch and
sum of tooth sizes of a mandibular arch.
33. The computerized method according to claim 32, wherein the
determining step includes a step of: determining the anatomical
correction in the maxillary arch using the following formula:
X=L/R-U, wherein, X is the anatomical correction in the maxillary
arch, L is the sum of the tooth sizes of the mandibular arch, R is
a ratio, and U is the sum of the tooth sizes of the maxillary
arch.
34. The computerized method according to claim 33, wherein the
ratio is one of 0.772 for a six-tooth analysis and 0.913 for a
twelve-tooth analysis.
35. The computerized method according to claim 32, wherein the
determining step includes a step of determining the anatomical
correction in the mandibular arch using the following formula:
Y=(U.times.R)-L, wherein, Y is the anatomical correction in the
mandibular arch, U is the sum of the tooth sizes of the maxillary
arch, R is a ratio, and L is the sum of the tooth sizes of the
mandibular arch.
36. The computerized method according to claim 35, wherein the
ratio is one of 0.772 for a six-tooth analysis and 0.913 for a
twelve-tooth analysis.
37. An arch wire, comprising: a metal wire sized to fit a maxillary
arch, the metal wire having a radius of curvature of one of 25.4125
mm, 26.75 mm and 28.0875 mm.
38. The arch wire according to claim 37, wherein the metal wire
includes super-elastic preformed arch wires.
39. The arch wire according to claim 37, wherein the metal wire has
one of a round, a square, and a rectangular cross-section.
40. An arch wire, comprising: a metal wire sized to fit a
mandibular arch, the metal wire having a radius of curvature of one
of 25.4625 mm, 24.25 mm and 25.4625 mm.
41. The arch wire according to claim 40, wherein the metal wire
includes super-elastic preformed arch wires.
42. The arch wire according to claim 40, wherein the metal wire has
one of a round, a square, and a rectangular cross-section.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to the field of orthodontics,
in particular a computerized system and method for identifying and
correcting tooth-size discrepancies, and determining a recommended
arch size predicated on a patient's cranial-facial morphology and
tooth size.
BACKGROUND INFORMATION
[0002] In the field of orthodontics, a mathematical ratio exists
between the size (mesiodistal width) of the upper (maxillary) and
lower (mandibular) teeth. This mathematical ratio should exist in
an ideal dental occlusion. More often than not, and particularly in
patients with orthodontic problems, a tooth-size discrepancy
exists. Although there are no reliable epidemiological studies
confirming these statistics, it is estimated that approximately
one-third of the American public have tooth sizes that are
proportional and within a reasonable range of an ideal occlusion.
The remaining two-thirds of the American public, however, have
teeth where the mathematical ratio is not ideal and there exists a
modest to severe tooth-size discrepancy or incompatibility.
[0003] In a scientific research paper entitled "Disharmony in Tooth
Size and Its Relation to the Analysis and Treatment of
Malocclusion" by Dr. Wayne A. Bolton, a method is described for
identifying the presence and magnitude of a tooth-size discrepancy
(the "Bolton Analysis"). This method may be performed on the six
anterior teeth (two canines, two laterals, and two central
incisors) or on twelve teeth (the six anterior teeth, the four
premolar teeth, and the two first molar teeth). The mathematical
ratio is compared to the ideal mathematical ratio, which is 0.772
for the six anterior teeth, and 0.913 for the twelve teeth
analysis. This comparison identifies any existing tooth-size
discrepancy and the magnitude of the tooth-size discrepancy, which
is the difference between the mathematical ratio and the ideal
mathematical ratio.
[0004] Typically, the Bolton Analysis is performed using the tables
provided in Bolton's paper, a slide rule, which is no longer
manufactured, or a calculator. Therefore, determining the existence
of a tooth-size discrepancy using the Bolton Analysis can be very
tedious and time consuming. While the Bolton Analysis determines
the existence and the magnitude of a tooth-size discrepancy, it
does not quantify the mathematical correction necessary in the
maxillary and/or mandibular teeth to achieve an ideal occlusion.
Thus, there exists a need for a computerized system that measures
teeth and accurately determines the existence and magnitude of a
tooth-size discrepancy in an easy and expeditious manner.
[0005] The failure of an orthodontist to recognize the existence
and amount of the tooth-size discrepancy during diagnosis, and to
attain a close to ideal ratio of tooth structure during treatment,
may result in treatment problems, such as crowding or spacing of
the maxillary and/or mandibular teeth. Deviations from the ideal
ratio may also result in a relapse of treatment and/or functional,
aesthetic and health problems.
[0006] A problem arises, however, when the orthodontist attempts to
correct the tooth-size discrepancy determined using the Bolton
Analysis. Since the results of the Bolton Analysis are directly
related to a ratio, the results do not accurately address the
amount of actual anatomical correction necessary in either the
maxillary or mandibular arch. As soon as a change is undertaken in
any direction, the ratio changes. An orthodontist assuming that a
tooth-size discrepancy can be corrected merely by adding to or
removing the amount of tooth structure indicated by the results of
the Bolton Analysis, in either the maxillary or mandibular arch,
will err. Moreover, the results of the Bolton Analysis do not
clearly demonstrate to the orthodontist or researcher the actual
tooth or teeth prompting the tooth-size discrepancy. Thus, there
exists a further need for a computerized system that determines the
amount of anatomical correction necessary using the results of the
Bolton Analysis. It would be desirable if this system would
illustrate, on a monitor and/or in a printer output, the actual and
average size of each tooth so that it is immediately apparent to
the doctor the tooth or teeth that may be responsible for the
tooth-size discrepancy.
[0007] Preformed arch wires such as super-elastic preformed arch
wires are frequently used during the first and second phases of
treatment to level, align, torque, and/or shape the teeth and the
arches. Current orthodontic use of preformed arch wires (one for
the maxillary arch, one for the mandibular arch) means that
approximately 17% of patients are treated with an arch wire that is
too large and 17% of patients are treated with an arch wire that is
too small. Since these preformed arch wires are not adjustable to
the patient's facial size, they may create problems by over
expansion or constriction of the maxillary and/or mandibular arch.
These problems might be corrected later in treatment, when it is
least desired, and would extend the treatment time. In addition,
the use of these preformed wires may also result in "round
tripping," i.e., moving the teeth in the wrong direction and then
having to recorrect the teeth. Thus, there exists a further need
for a computerized system that determines the ideal arch wire size
to effectuate a more precise and stable treatment.
SUMMARY OF THE INVENTION
[0008] The computerized system according to an example embodiment
of the present invention determines the existence and magnitude of
a tooth-size discrepancy, the necessary anatomical correction, the
identity of the individual tooth or teeth responsible for the
tooth-size discrepancy and the recommended arch wire size to
effectuate treatment of the tooth-size discrepancy. The
computerized system includes a computer with various input/output
devices that include a computerized caliper. The computer executes
a program that performs an analysis and outputs (1) the sums of the
maxillary and mandibular arches, (2) the necessary anatomical
correction, (3) the individual tooth or teeth responsible for the
tooth-size discrepancy and (4) the recommended arch wire size. The
computerized caliper is used to measure the mesiodistal width of
each tooth. The computerized caliper directly inputs each
tooth-size measurement into the computer.
[0009] Once the user has inputted the individual measurements for
the teeth involved in the analysis, the user may compare the
measurements with the average measurement for each tooth via a
monitor and/or a printer output.
[0010] Using the inputted information, the program determines the
magnitude of the tooth size discrepancy, the necessary anatomical
correction and the recommended arch wire size. Once the tooth-size
discrepancy is determined, the user may utilize the necessary
anatomical correction along with a comparison of the measurements
to the average sizes to determine the proper diagnosis, i.e., how
much correction to make in the maxillary teeth, the mandibular
teeth or a combination of the two.
[0011] The method according to the example embodiment of the
present invention uses the selected arch wires during the entire
course of treatment. The arch wires are selected on the basis of
the tooth-size measurements of the patient.
[0012] In other embodiments, the constants used to calculate the
tooth-size discrepancy, anatomical correction necessary, and the
arch wire size are adjusted for the statistical differences based
on race.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 illustrates a computer system according to the
present invention.
[0014] FIG. 2A illustrates a first screen display of a program
according to the present invention.
[0015] FIG. 2B illustrates a second screen display of a pull down
menu from the screen display shown in FIG. 2A.
[0016] FIG. 2C illustrates a third screen display of a program
implementing the flow chart shown in FIG. 3.
[0017] FIG. 2D illustrates a fourth screen display of a program
implementing the flow chart shown in FIG. 3.
[0018] FIG. 3 illustrates a flowchart of a software program
according to the present invention for determining tooth-size
discrepancy, necessary anatomical correction, individual teeth
responsible for the tooth-size discrepancy and a recommended arch
wire size for the maxillary and mandibular arches.
[0019] FIG. 4 illustrates a view of a set of small medium and large
arch wires according to the present invention.
DETAILED DESCRIPTION
[0020] An example embodiment of the present invention is explained
in further detail with reference to the drawings. FIG. 1
illustrates a computer system according to the present invention.
The computer system includes a central processing unit 101, a first
storage device 102, a second storage device 103, a dynamic memory
device 104, and input/output devices 105, 106, 107, 108 and 109.
The central processing unit 101 is for executing computer programs,
in particular a software program determining tooth-size
discrepancy, necessary anatomical correction, the tooth or teeth
responsible for the tooth-size discrepancy, and arch wire size, and
for managing and controlling the operation of the computer
system.
[0021] The first storage device 102, such as a floppy disk drive,
is coupled to the central processing unit 101 for reading and
writing data and computer programs to and from removable storage
media, such as floppy disks. The second storage device 103 is also
coupled to the central processing unit 102 and provides a means for
storing computer programs and data. The second storage device 103,
however, may be, for example, a hard disk drive having a high
storage capacity.
[0022] The dynamic memory device 104, for example a RAM, is coupled
to the central processing unit 101. The computer system includes
typical input/output devices, such as, for example, a keyboard 105,
a mouse 106, a printer 108, and a monitor 109. The computer also
includes an input/output device for measuring the mesiodistal width
of teeth, such as, for example a computerized caliper 107.
[0023] In the example embodiment the computerized caliper 107 may
be a digital caliper such as, for example, the Fowler "Max-Cal: The
Computerized Caliper," order no. 54-200-000 or 54-200-0008. This
device may be modified in accordance with the example embodiment.
For example, the measuring tines may be retooled so that they are
sharply pointed and appropriate for highly accurate measurement of
individual teeth. The actual teeth or a plaster model of the teeth
may be measured. It should be noted that if the actual teeth are
measured, then the computerized caliper should be sterilized.
[0024] A driver is provided to read the input from the caliper 107.
This driver is capable of detecting each measurement taken by the
caliper 107 after an enter button of the caliper 107 has been
pressed. The driver, for example, determines which communications
port of the computer system shown in FIG. 1 the caliper is
connected. Further, the driver, for example, establishes a
communications link between the caliper 107 and the computer
system.
[0025] FIG. 2A illustrates a screen display in which the user 32
enters patient information, for example, the patient's name, age
and gender and any missing or malformed teeth.
[0026] FIG. 2B illustrates a pull-down menu 205 for selecting
whether the keyboard 105 or the caliper 107 will be used to input
the measurements. If the measurements will be entered via the
keyboard 105, the user should select none. If the measurements will
be entered via the caliper 107, the user should select the
communicatio port, i.e. COM1, COM2, etc., to which the caliper 107
is connected. Once the user has selected the input device and
inputted the patient information, the user must select the "NEXT"
button to implement the program shown in FIG. 3.
[0027] FIGS. 2C and 2D are screen displays of a program
implementing the flow chart shown in FIG. 3. The program may be
implemented using any conventional programming language, such as
C++.
[0028] FIG. 2C illustrates a screen display in which the user has
inputted the individual tooth sizes necessary for a six-tooth
analysis. As shown in FIG. 2C, the user may select six-tooth
analysis at radio button 201 or twelve-tooth analysis at radio
button 202. The user may also select to input either the individual
tooth sizes at radio button 203 or the sums of the maxillary and
mandibular arches at radio button 204. In this case, the user has
selected six-tooth analysis and to input the individual tooth
sizes. These selections may be accomplished via the keyboard 105 or
the mouse 107. If the user had selected to input the sums rather
than the individual measurements, then the user inputs the sums at
entry points 207 and 208 for six-tooth analysis and entry points
209 and 210 for twelve-teeth analysis.
[0029] At this stage, the user inputs the measurements via the
keyboard 105 or the caliper 107. If the user has selected the
keyboard 105 as the input device, the user enters the measurements
in the order indicated using the keyboard 105 and press the enter
key of the keyboard 105. In the example embodiment, the order for
entering the measurements is indicated by highlighting the
measurement to be taken as shown at entry point 206. Above entry
point 26, the average size for the upper right canine, 7.91 mm, is
shown.
[0030] If the user has selected the caliper 107 as the input
device, the user uses the caliper 107 to measure the mesiodistal
width of each of the teeth and presses the enter button on the
caliper 107 after each measurement. After all the measurements are
entered the user should click on the "print" button 211 and/or
"calculate" button 212. The "print" button 211 prints out the
screen display as shown in FIG. 2C with all of the inputted
measurements. The "calculate" button 212 executes the determination
of the arch size, tooth-size discrepancy, necessary correction, and
the arch wire size, resulting in a screen display as shown, for
example, in FIG. 2D.
[0031] FIG. 2D illustrates a screen display of an analysis summary
of an output of a program implementing the flow chart shown in FIG.
2. The screen display shows the maxillary arch sum 213, mandibular
arch sum 214, any necessary anatomical correction 215, 216, and the
recommended arch wire size 217. In this particular case, the sum of
the maxillary arch is 44.28 mm and the sum of the mandibular arch
is 36.19 mm. The necessary anatomical correction is an increase in
the maxillary arch by 2.6 mm or a reduction of the mandibular arch
by 2.01 mm. This indicates that the mesiodistal width of the
maxillary teeth should be increased by 2.6 mm, and the mesiodistal
width of the mandibular teeth should be decreased by 2.01 mm. The
orthodontist, however, may also decide to implement a treatment
that is a combination of the two calculations. The recommended arch
wire size 217, in this case, is "small."
[0032] The teeth responsible for the tooth-size discrepancy may be
determined by viewing the screen display shown in FIG. 2C after
inputting all of the individual teeth measurements. This particular
screen display shows the average size for each tooth either above
or below the tooth's measurement. For the maxillary teeth, the
average size is displayed above each measurement. The average size
for the mandibular teeth is displayed below each measurement. The
user may determine the teeth responsible for the tooth-size
discrepancy by comparing the measurement to the average size for
each particular tooth.
[0033] FIG. 3 illustrates a flowchart of a software program
determining tooth-size discrepancy, the necessary tooth-size
correction, the individual teeth responsible for the tooth-size
discrepancy, and arch wire size according to the present
invention.
[0034] During execution of the program, a user selects either six
or twelve via the keyboard 105 or the mouse 106 to indicate whether
six-tooth analysis or twelve tooth analysis will be used (Block
301). Next, the program determines whether six-tooth or twelve
tooth analysis was selected (Blocks 302 and 304). If the user
indicated six-tooth analysis, the ideal mathematical ratio R is set
to 0.772 (Block 303). If the user indicated twelve-tooth analysis,
the ideal mathematical ratio is set to 0.913 (Block 305), otherwise
the program returns to the beginning of the program (Block
301).
[0035] After the ideal mathematical ratio R is set, the program
determines whether individual tooth sizes or the sums of the
individual tooth sizes of each arch will be entered (Block 306). If
the sums are to be entered, the user inputs the sum of the
mesiodistal widths of the maxillary teeth U (Block 307). Likewise,
the user inputs the sum of the mesiodistal widths of the mandibular
teeth L (Block 308). If the mesiodistal widths for the individual
teeth are to be inputted, the user is prompted to input the
individual mesiodistal widths for the maxillary teeth and the sum
of the mesiodistal widths of the maxillary teeth U is determined
(Block 309). Likewise, the user is prompted to input the individual
mesiodistal widths for the mandibular teeth and the sum of the
mesiodistal widths of the mandibular teeth L is determined (Block
310).
[0036] Next, the necessary anatomical correction in the maxillary
and mandibular arches are determined. The magnitude of the
necessary anatomical correction in the maxillary arch, X, is
rounded to the nearest hundredth of millimeters (Block 311).
[0037] The necessary anatomical correction for the maxillary arch,
X, is determined according to the following equation:
X=L/R-U (1)
[0038] The necessary anatomical correction for the mandibular arch,
Y, is determined according to the following equation:
Y=(U.times.R)-L (2)
[0039] Then, the necessary anatomical correction for the maxillary
arch, X, is compared to zero (Block 312). If the necessary
anatomical correction for the maxillary arch, X, is greater than
zero, then the program outputs that the mesiodistal width of the
teeth in the maxillary arch should be reduced by the rounded X
(Block 313). If the necessary anatomical correction for the
maxillary arch, X, is less than zero, then the program outputs that
the mesiodistal width of the teeth in the maxillary arch should be
increased by the rounded X (Block 314). If the necessary anatomical
correction for the maxillary arch equals zero, then there is no
tooth-size discrepancy and no anatomical correction is
necessary.
[0040] Next, the magnitude of the necessary anatomical correction
in the mandibular arch, Y, is rounded to the nearest hundredth of
millimeters (Block 315).
[0041] The necessary anatomical correction in the mandibular arch,
Y, is then compared to zero (Block 316). If the necessary
anatomical correction, Y, is greater than zero, then the program
outputs that the mesiodistal width of the teeth in the mandibular
arch should be reduced by the rounded Y (Block 317). If the
necessary anatomical correction, Y, is less than zero (0), then the
program outputs that the mesiodistal width of the teeth in the
mandibular arch should be increased by the rounded Y for the
mandibular arch (Block 318). If the necessary anatomical
correction, Y, for the mandibular arch equals zero, then there is
no tooth-size discrepancy and no anatomical correction is
necessary.
[0042] Finally, the recommended arch wire size is selected and
displayed to the user (Block 319). If the sum of the maxillary
teeth is less than 44.5 mm, then a set of small arch wires is
selected for the maxillary and mandibular arches. If the sum of the
maxillary teeth is greater than 44.5 mm but less than 49.4 mm, then
a set of medium arch wires is selected for the maxillary and
mandibular arches. If the sum of the maxillary teeth is greater
than 49.4 mm, then a set of large arch wires is selected for the
maxillary and mandibular arches. These parameters were determined
based on the standard deviation of the average sum of the maxillary
anterior tooth sizes of the patients with an untreated ideal
occlusion used in the Bolton scientific study.
[0043] Once the necessary anatomical correction in the maxillary
and mandibular arches has been calculated according to the present
invention, the orthodontist may select a conventional method of
treatment. The orthodontist may correct the arch size discrepancy
by one or a combination of the following methods:
[0044] 1. Selective and measured reduction of the mesiodistal
widths of selected teeth by interproximal stripping (reduction of
the enamel surfaces by the necessary correction).
[0045] 2. Extraction.
[0046] 3. Prosthetic replacement of teeth or addition of teeth in
accordance with the necessary correction.
[0047] 4. Prosthetic treatment utilizing composite additions,
veneers or jacket crowns altering the size of existing teeth.
[0048] The recommended arch wires should be used during the entire
course of treatment. In the example embodiment, the selected arch
wires are used through the entire course of treatment, i.e., from
beginning through the end. Use of an arch wire according to the
present invention, addresses three problems. First, determination
of the arch size by measurement of the teeth assures, with few
exceptions, that the treatment outcome will provide facial and
skeletal, functional and aesthetic harmony with the patient's face
and jaws. Second, the arch wire selected by the present invention
is adapted to the individual patient's tooth-size preventing
over-expansion or constriction of the arch during the course of
treatment. Third, the arch wire according to the present invention
may prevent "round tripping" caused by moving teeth in wrong
directions and then correcting them again. Such movement may create
severe iatrogenic sequelae.
[0049] FIG. 4 is an illustration of a set of small, medium and
large arch wires according to the present invention. Each set
contains an arch wire for the maxillary arch and the mandibular
arch. The large arch wire for the maxillary arch has an approximate
radius of curvature of 28.0875 mm. The large arch wire for the
mandibular arch has a radius of curvature approximately equal to
25.4625 mm. The medium arch wire for the maxillary arch has a
radius of curvature of approximately 26.75 mm. The medium arch wire
for the mandibular arch has a radius of curvature of approximately
24.25 mm. The small arch wire for the maxillary teeth has a radius
of curvature of approximately 25.4125 mm. The radius of curvature
is approximately 23.0375 mm for the small arch wire for the
mandibular arch. The radius of curvatures for each of the arch
wires is determined from historical patient data, with the small
and large arch wires being plus and minus one standard
deviation.
[0050] The arch wires are made of, for example, stainless steel
and/or nickel-titanium (NiTi) and may be, for example, either
round, rectangular or square. The size for round arch wires made of
NiTi are, for example, 0.014 inch, 0.016 inch, and 0.018 inch. The
dimensions for rectangular NiTi arch wire are, for example, 0.016
inch.times.0.016 inch, 0.016 inch.times.0.022 inch, 0.017
inch.times.0.025 inch, 0.018 inch.times.0.025 inch, 0.02
inch.times.0.02 inch, and 0.021 inch.times.0.028 inch. The
dimensions for Bioforce arch wires are, for example, 0.016
inch.times.0.016 inch, 0.016 inch.times.0.022 inch, 0.018
inch.times.0.018 inch, 0.018 inch.times.0.025 inch, 0.02
inch.times.0.02 inch, 0.021 inch.times.0.028 inch.
[0051] The tooth-size discrepancy, necessary correction, and arch
wire size are determined using, in part, the ideal mathematical
ratio from the Bolton Analysis. The original Bolton Analysis as
described in the paper entitled "Disharmony in Tooth Size and Its
Relation to the Analysis and Treatment of Malocclusion" included
only Caucasian patients. In another embodiment, the present
invention adjusts its calculations to compensate for the modest but
statistically significant difference specific to other races. The
method and process remain the same, however, the ideal ratio and
average sizes for individual teeth would vary based on these
statistical differences.
* * * * *