Note: Descriptions are shown in the official language in which they were submitted.
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T I T L E
_ .
METHOD AND APPARATUS FOR THE NON-INVaSIVE
EXaMIN~TION OF THE TOOTH-JAW STRUCTURE OF
A PATIENT TO DETERMINE THE CHARaCTERISTICS
OF UNERUPTED TEETH AND TO CONTROL NUTRITIONAL
INTAKE PURSUANT THERETO
_ _
FIELD OF THE INVENTION
This invention relates generally to dental measurement,
and more particularly to a system for measuring, analyzing, and
eontrolling the growth of primary dentition soon after birth by
controlling nutri-tional intake. Such measurements are impor-tant
and useful because the detection of incipient states of dental
crowding (malocclusions) in early infancy permits the practitioner
to offer appropriate therapeutie measures before the dental
crowding progresses into a frank malocclusion.
BACKGROUND
Current methods for studying incipient states of dental
crowding during early infancy are radiological and include the
use of X-ray techniques thereby exposing neonates and young
children to ionizing radiation. There is growing concern with
adverse effects that may result from exposure to X-rays.
Onee that danger is circumvented, the problem is to
identify those infants who are at risk for developing handi-
capping malocclusion due to the size of jaw being too small for
the size of the tee-th, which shows up acutely when there is not
enough spacing in the primary dentition for changeover to the
larger permanent teeth, a condition known as incisor liability.
Knowing that the width of the arch can only increase during the
first serval mon-ths after birth, the question is how to promote
this growth of the jaw for an infant who is identified as heing
at risk for crowding. Once the infant's genetic potential
for growth is determined by measuring an unerupted primary tooth
it becomes possible to apply nutritional means for reaching the
genetically correct amount of growth; however, it is necessary
to control and periodically modify the calorie inta]ce based on
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changing amounts of growth ancl the time cons-traint for arch
width increase. It is also necessary to provide a process for
automatically controlliny the feeding of approxima-tely forty
percent of the infants who need large amounts of nutrients due
to a severe risk Eor crowding.
A significant clinical feeding problem addressed by
the present invention relates to the hospital care of premature
infants. After the acute crisis subsides with intensive feeding
measures, the attending physician needs a quantitative criterion
in order to set a desirable calorie flow rate for a particular
premature infant.
Another important practical problem for the physician
is to utilize an acceptable cri-terion that will convince infant
caregivers to follow professional feeding orders rather than
parental zeal or prejudices, in order to avoid infant overfeeding
(obesity) or underfeeding problems. Such a criterion is inherent
in the invention.
The term "tooth-jaw structure" is intended to refer -to
the general structure of the patient inclusive of the gums. It
is to be appreciated that it is the gums which are irradiated to
provide outline of the unerupted teeth present in the gums.
SUMMARY OF THE INVENTION
It is therefore an important object of this invention
to provide apparatus for measuring and analyzing the growth and
development of tooth-jaw structures which does not employ X-rays
or other ionizing radiation of film.
In view of the foregoing, transillumination of the tooth-
jaw structures with non-ionizing photons and subsequen-t de-tection
of those photons which have transilluminated the tooth-jaw
structures is an important object of this invention.
Those skilled in the art will understand that photon
sources for -transillumination should be of sufficient intensity
to penetrate and traverse the anatomical portion being studied.
This may be provided by several means. An incandescent lamp may
provide such photons. It will be understood by those skilled
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in the art that a convenient means of using an incandescent
light source is -to use a reflector-type lamp housed in a light
beam projector. A fiber optic type of light beam projector will
also provide this function. The lamp may be used with a focusing
lens with or without said fiber optic element. Yet another
photon source may be a light emitting diode. The advantage of
this light source is its low voltage and current requirements.
A light emitting diode of the infrared type may be advantageous
since infrared photons can provide good contrast between tooth-
jaw or other structures. Infrared light emitting dlodes arealso advantageous because they are detectable by photodetectors
which respond principally in the infrared region of the spectrum
thereby limiting the adverse affects of ambient light. Since
a high intensity liqht source is useful in transilluminating
methods, the use of a laser photon source is of particular utility
due to its high intensity. Furthermore, such devices are
available which emit in the infrared region and are of the light
emitting diode type thereby providing high intensity, improved
contrast, low voltage and current power requirements and the
aforementioned immunity to ambient light of a system employing
an infrared light source with a matched photodetector.
Another object of this invention is to provide apparatus
for measuring the size, space and distance between and among
tooth-jaw structures. This is provided by the combined use of
a photodetector and linear displacement transducer in integral
conjunction with the aforementioned light source and beam
projector. The photodetector senses photons which have trans-
illuminated the anatomical portion of interest. In the case of
tooth-jaw structures under transillumination, a tooth, either
unerupted or erupted will block the transmission of light from
the integral light beam source. The photodetector will sense
-the change of intensity of transilluminating pho-tons. The photo-
detector in the preferred embodiment is a phototransistor,
however, it will be understood by those skilled in the art that
a variety of photodetectors may be used wi-thin the invention.
These include but are not limited -to photodiodes, photomultipliers,
photoresistors, photovoltaic devices, vidicon tubes and charge
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coupled devices.
Nuclear magnetic resonance can be employed instead of
light. This invo~ves applying a fixed magnetic field to the
target tissue area, along with an oscillating elec-tromagnetic
field from a miniature radio transmitter and a miniature radio
receiver to detect the re-radiation from said body tissues.
The position of said radio receiver would be transduced to
provide the desired tooth width and interdental spacing measure-
ments.
In a presented embodiment, the integral linear displace-
ment transducer is a linear output Hall effect device. This
magnetically sensitive device is used in conjunction wi-th a magnet
to provide a change in output as a function of distance from the
magnet which serves the duel function of providing a magnetic
field for the Hall sensor, and a datum or reEerence in determining
the distance of the integral photodetector from the magnet. The
magnet is of the rare earth type in general and more specifically,
samarium cobalt. This type of magnet has a highly stable field
strength and a high energy product providing an accurately
measureable field throughout the distances needed to perform the
measurement. Other magnets may be employed within the scope
of the invention.
A further object of this invention is to provide a
system of the above type which is electronically isolated from the
practitioner and patient thereby avoiding the hazard of electrical
shock. This may be accomplished by the use of optoisolators and
insulated shielded wiring.
A further object of the invention is to provide a
system of the above type which includes means for processing the
outputs of the linear displacement transducer and the photodector
such that the practitioner can be provided with the desired
measurements. This may be accomplished by feeding said signals
into a subsystem comprising sample and hold amplifiers, analog
to digital converters, display electronics, storage electronics,
si~nal processing electronics and a power supply -to energize
said signal acquisition and processing electronics. The above
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function can be perEormed by a variety of means including but
not limited to such data translation methods as data acquisition
modules, comprising multiplexing circuitry, sample and hold
amplification circuitry, analog to digital conversion circuitry
and interface circuitry for subsequent processing by a computer
system.
The computer system may be microprocessor based, micro-
computer based, minicomputer based or mainframe computer based.
Such data acquisition and signal processing subsystems may
include signal conditioning circuitry and software to achieve
the desired analysis and result. Such circuitry may include
but is not limited to analog multipliers, true RMS converters,
active filters, digital filters, digital signal processing devices
such as Texas Instruments TMS 320, TRW TD 1023J, Intel 2920,
American Microsystems S 2811 and NEC 7720.
It will be understood by those skilled in the art that
the software to work in conjunction with data acquisition,
conditioning and processing circuitry and subsystems may reside
in programmable read-only-memory devices, erasable programmable
read-only-memory devices, the aforementioned digital signal
processing devices, magnetic tape or disk drive systems or other
data storage devices or systems. Algorithms for such processing
subsystems may include but are not limited to image processing
methods exemplified by skeletization, inverse skeletization,
feature extraction, content addressing, look-up table, associative
addressing, spectrum analysis, fast Fourier transforms, inverse
fast Fourier transforms, convolution integration and inverse
convolution integration. Such algorithms may be implemented on
the aforementioned digital signal processing devices upon their
manufacture or fabrication thereby made available as an integral
feature of said devices.
Another important ob~ect of this invention is to perform
the analysis of data acquired during and after -the use of the
above system by means other than those disclosed and the
aforementioned methods are merely examples of the implementation
of analysis and are not to be construed as limitations upon
the several aforementioned methods of tooth-jaw analysis.
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In accordance with the above, the invention provides for
apparatus for the non-invasive examination of the tooth-jaw
structure of a patient to determine the characteristics of un-
erupted teeth in said structure wherein the apparatus comprises
means for producing a beam of energy outside the X-ray region and
within the region of infrared, visible light or ultrasound. The
beam producing means is mounted on a support means for positioning
the beam producing means such that the beam of energy therefrom
strikes the tooth-jaw structure and undergoes modification
depending on the presence of unerupted teeth and their size and
position in the tooth-jaw structure. A receiver means is mounted
on the support means for receiving the beam of energy after striking
the tooth-jaw structure to produce the characteristics of unerupted
teeth in said structure. Coupled to the receiver means is a
locator means for producing an indication of the location of the
receiver means such that the characteristics of the unerupted
teeth are related spatially.
Preferably, the support means comprises a portable hand-
held unit adapted for being placed adjacent to the tooth-jaw
structure.
In a preferred embodiment, the beam producing means
comprises a light source for transilluminating the jaw structure,
the receiver means is a photodetector and the locator means is
a linear displacement transducer.
The invention is also concerned with a method of deter-
mining the growth of primary dentition in the tooth-jaw development
process without the use of X-rays and the method comprises
irradiating the tooth-jaw structure, in the course of development
thereof by a beam of non-ionizing energy from a non-X-ray source~
In further accordance with the method of the invention, the beam
of energy is received after irradiation of the tooth-jaw structure
by the beam and information indicating the presence or absence
of unerupted teeth in the gums of the tooth-jaw structure and the
size, spacing and location of said unerupted teeth are produced
whereby the growth of primary dentition can be determlned.
The method of the invention also contemplates controlling
the calorie intake of the patient in accordance with the determined
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values of the size, spacing, and location of the unerup-ted teeth
so that the growth of primary dentition is regulated -to provide
desired interdental spacing and consequent tooth-jaw concordance.
BRIEF DESCRIPTION OF THE SEVERAL
VIEWS OF THE DRAWING
Figure 1 is a fron-t view diagrammatically illustrating
-the apparatus of the invention of use in the irradiation of a
tooth-jaw structure.
Figure 2 is a side elevational view of the structure
shown in Fig. 1.
Figure 3 is a diagrammatic illustration of an operating
system utilized with the apparatus of the invention.
Figure ~ shows a front view of a modified structure.
Figure 5 is a plan view from above of the structure in
Fig. ~, showing an interchange in the position of two means.
Figure 6 is a side view partly in section showing a
modification of the structure.
Figure 7 is a plan view from above of the structure in
Fig. 5.
Figure 8 is a block diagram of another operating
system according to the invention.
Figure 8A is a more detailed schematic illustration
of the system of Figure 8.
Figure 9 is a schematic illustration of a system for
achieving concordant infant dental growth.
DETAILED DESCRIPTIONS
The invention will be described in detail hereafter w:ith
reference to a system for measuring, analyzing, predicting, and
controlling nutrition for preventing or reducing dental crowding
and promoting desirable infant dental growth. More particularly
this is done through a computer or microprocessor based system
that is specifically programmed according to this invention.
One aspect of the invention is to determine to what degree, if
any, tested infants are at risk to develop malocclusion due to
malnutrition. rrhis can be related -to the marked decrease in
food intake that takes place, generally, at two months of age
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which is a crucial time when the infant's jaw is capable of
favorable anterlor gxowth pat-terns.
The inven-tion considers this reduction in food intake
to be a prime environmental factor in the development of tooth-
arch discrepancies in susceptible infants. An infant's food
consumption requirements for concordant growth, as defined later
herein, can be assessed from tooth size and the genetic potential
for growth that such size variations intrinsically represent.
In use, the first examination of the infant by means of the
invention establishes and enters age and body length into the
computer, and sensors will measure tooth wid-th and interdental
spacing from illuminated gums and also provide this as an input
to the computer. In follow up examinations, it is unnecessary
to enter the infant's age because a real-time clock calendar
will be incorporated in the computer. Furthermore, in follow
up examinations it is optional to measure -tooth width since
this does not change once the tooth is fully calcified, and,
in connection wi-th the upper primary central incisor tooth, this
occurs prior to two months of age. It is also optional to measure
body length after its initial entry, since an infant's growth
can be assessed by measuring the amount of interdental spacing
with the oral sensors.
Another aspect of the invention is to use the information
from the computer analysis, described subsequently, for
determining the infant's degree of risk for developing crowding,
in order to control the flow rate of liquid nutrients through
an infant feeding tube, which may be administered by a physican
nasogastrically, enterally, or parenterally. The control of the
flow rate may be accomplished by an Oriel precision motorized
micrometer or other suitable computer controlled means known -to
those skilled in the art. Alternatively, in situations where
the infant's growth discrepancy is small, -the computer can
produce schedules for breast or bottle feeding.
Still another objective of this invention is to provide
a multi-task computer capable of simultaneously monitoring and
controlling the feeding of a number of infants through a local
area network controller.
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This invention involves the evaluation of dental growth
concordance and -the nutritional recommendations for correcting
nonconcordance which are arrived at taking into account the
following factors incorporated into a computer program of the
present type:
1. The body length of the infant is measured and based
on the infant's age, a body length percentile (hereafter %tile)
is determined on the basis of growth %tile values from standard
tables that have been programmed into the computer as look-up
tables.
2. The tooth width of the infant is measured and this
value in millimeters is multiplied by a factor K to obtain a
theoretical body length %tile. The factor K is the ratio of
the maximum body length %tile of a given population to the
maximum tooth width of the population and the value K may vary
for different populations. A typical value of K may be in the
range between 10 and 15.
3. The tooth-jaw concordance is determined by sub-
tracting the actual body length %tile from the theoretical body
length %tile to obtain length %tile discrepancy. In the small
fraction of cases where the actual body length %tile is equal
to or exceeds the theoretical body length %tile, no change in
the calorie intake is needed, however, follow up exams may be
useful. In general/ the theoretical body length %tile is the
maximum growth %tile that can be reached; if it is not reached
varying degrees of dental crowding will probably result.
4. It has been found that this discrepancy is related
to interdental spacing by the following empirical regression
equation:
snatceirngnmml = -0.4546 x %tile Discrepancy ~ 0 4407
100
The empirical equation is additive since tooth-jaw
concordance or lack thereof (i.e. crowding) is adequately
represented by the body length %tile discrepancy factor and
since interdental spacing may be measured directly with the
oral status measuring sensors of this inven-tion.
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5. For a particular age and based on a theoretical
body length ~tile, a theoretical daily calorie intake can be
obtained from various loolc-up tables programmed in the computer.
In order to determine the remedial daily calorie intake when
catch-up growth is indicated, the invention contemplates that to
the theoretical body length %tile is added the discrepancy
factor i.e., the body length %tile discrepancy. As a consequence,
a remedial daily calorie intake is obtained.
6. The position of the motorized micrometer, or other
means, required to provide the desired nutrient flow ra-te corre-
sponding to the calculated theoretical daily calorie intake, or
an intermediate value, is adjusted automatically by means described
or known to those skilled in this art.
Although the tooth width and, hence, theore-tical body
length %tile does not change as a particular infant gets older,
and although actual body length %tile normally does not change,
it is expected that when a corrective regimen of calorie intake
and necessary care is supplied to an infant who is below his or
her theoretical body length %tile and, thus, at risk for developing
tooth crowding, the infant's actual body length %tile will
increase towards the theoretical standing and simultaneously the
growth of the jaw (arch width) will increase to reduce the degree
of crowding until approximately six months after birth.
7. Hence, it is desirable to follow the progress of
the infant on a serial basis as often as may be deemed necessary
and to determine the reduction in body length %tile discrepancy
and the reduction in tooth crowding. At each age, a new corrected
calorie intake will be calculated and the regimen can be modified
to find a "critical path" to the correct calorie intake and to
the ideal amount of interdental spacing estimate to be 0.~4 mm.
plus or minus sb obtained from the intercept of the "best fit"
line represented by the empirical-regression equation. The
critical path method takes the time factor into account, which
is important because the arch width can only increase until
approximately si~ months after birth. Nutrition and nutritionally
related means can only be effec-tive in reducing crowding during
this critical period.
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8. A further regression equation which is useful is
Interdental Spacing = _ 0668 x %tile Discrepanc~ + 0.0684
Tooth Width 100
9. When the invention is -to be employed for prema-ture
infants, the width of a transilluminated tooth at birth is
determined with oral sensors or analyzers. The computer's operating
subprogram multiplies the tooth width value by the reciprocal
of a known fraction representing the degree of completed crown
formation at birth. From this the system determines calorie values,
and sets the flow rates of feeding tubes accordingly to achieve
concordant dental growth for -these premature inEants.
Since the inven-tion is based on effecting flow rates
or feeding schedules for infants, it should circumven-t the zeal
or prejudices of infant caregivers that give rise to health problems
related to obesity or dehydration.
In all operations of the invention, the attending
physician or dentist are the final arbiters, and they are pro-
fessionally responsible for using their judgemen-t to accept, modify,
or reject the information or settings that the apparatus produces.
Figs. 1 and 2 show a simplified embodiment of an
analyzer or sensor for measuring the width of unerupted teeth and
interdental spacing without the use of ~-rays and in these figures
the tooth-jaw structure is designated D,E,F,G according to
American Dental Association nomenclature.
Fig. 9 illustrates schematically a system showing the
flow of data and control signals. The system operates according
to a feedback process as will be described later.
The analyzer comprises a portable hand-held unit 3
adapted for being placed adjacent to the tooth-jaw structure 1.
More particularly, the hand-held unit 3 comprises a front branch
4 and a rear branch 5 adapted to straddle the tooth-jaw structure
1 as seen in Fig. 2. The branch 4 is disposed facially i.e.
ex-ternally of the tooth-jaw structure while branch 5 is disposed
palatally i.e. within the mouth facing the interior surface of
the tooth-jaw structure 1. Mounted on the branch 5 of the unit
3 is a light source 6 for transilluminating the tooth-jaw
structure. The light source produces a beam of energy which is
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outside -the ,Y-ray region so as no-t -to expose the infant under
examination to ionizing racliation. The beam of energy is within
the region oE inErared, visible light or ultrasonic wavelengths.
As diagramma-tieally illustrated in Fig. 2, the beam of energy
produced by the light source is indicated by numeral 7 and strikes
a photocletector 8 mounted on the unit 4. The photodetector
serves as a receiver means for reeeiving the beam of energy after
it has undergone moclifieation upon passing through the tooth-jaw
strueture depending upon the presenee of unerupted teeth and their
size and position in the tooth-iaw s-tructure. The information
received by the photodeteetor is utilized to produee -the eharae-
teristies of unerupted teeth in the tooth-jaw strue-ture as will
be explained later.
Additionally supported on the branch 4 is a loca-tor means
9 which is in fi~ed relation to the photodetector 8. The locator
means serves to produce an indication of the location of -the
receiver means such that the characteristics of the unerupted
teeth ean be rela-ted spatially. In partieular locator means 9 is
constituted as a linear distance or displacement transducer as
will be e~plained hereafter.
The linear displacement transducer is a conventional linear
output Hall effect device as, for example, found in the commercial
market as exempliEied by the Honeywell-Microswitch 9SS (Lohet TM)
This is a magnetically sensitive deviee whieh employs a magnet
10 whieh establishes a field so that the loeator 9 provides a
ehange in output as a funetion of distanee from the magnet. Hence
the masnet serves the dual function of providing a magnetie field
for the loeator or sensor and a datum for referenee in determining
the distanee of the photodetector 8 from the magnet. As is well
~nown, the magnet 10 can be of the rare earth type and, particu-
larly, a samarium cobalt magnet. This type of magne-t has a
highlv stable fielcl strength and a high energy product providing
an accurately measurable field throu~hout -the distances needed
to perform the function of the analyzer of the invention.
The unit 3 can be battery powered, in which case it will
be self-eon-tained and fully portable without any eables of any
sort. The uni-t can also be externally powered, for example,
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through a cable 11 connected -to a suitable power source. A swi-tch
12 can be provided on -the unit 3 with separate posi-tions for
energizing the op-tic source alone and the optic source as well
as the linear displacement transducer.
In operation, the unit 3 is displaced along the tooth-jaw
structure and the light beam 7 traverses the tooth-jaw struc-ture
and undergoes alteration in accordance with the size and position
of the unerupted teeth D,~,F,G. An operating system 13 is
provided as shown in Fig. 3. The receiving means 8 comprises a
photodiode, such as a Vactec VTB9A13B, which is mounted on a
movahle linear displacement transducer 9, such as a Microswitch
9SS Hall-effect device. The CPU 29 is an 8 bit microprocessor, for
example, a Motorola 6809, which is loaded with appropriate data
processing software under control of the Basic interpreter stored
in read only memory 26 through the cassette I/O port 25, directing
the processing of the signals from transducers 8 and 9 into
meaningful tooth width and spacing measurements. The signals from
the receiving means 8 and the linear transducer 9 are fed into
sample/hold amplifiers 21 and 30 which supply acceptable signal
20 characteristics to the A/D converters 23 and 31 each having 12
bit resolutlon. The digitized output signals from the A/D conver-
ters are fed into the CPU 29 across a dedicated address space 27
on the data bus 22. The CPU 29 in turn processes the outputs as
follows. The digitized A/D output values are stored in random
access memory 2~, under software control, the CPU subtracts the
values which it has been determined correspond to the ends of the
unerupted teeth using standard signal processing techniques known
to those skilled in the art. The resulting measurements of tooth
width and interdental spacing are displayed on the operator CRT 28.
Many variations of the analyzer are within the skill of
those with knowle~ge in this art and, in particular, numerous
embodiments of different linear transducers are possible. By
way of example, reference is made to Figs. ~ and 5 which show the
provision of a unit 3' which carries a photodetector 8' and
transducer 9' for sliding movement along a curved support 33. The
transducer works in accordance with the Hall effect, but it is
modified as shown in Figs. 4 and 5 to obviate the need for a
separate magnet 10 positioned independently of the appara-tus.
In Fig ~, the transducer 9' travels along a curved support 33
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to correspond to the dental arch and forms a magnetopot with -the
magnet 39. In Fig. 5, the photode-tector 8' is integrally mounted
on the magnet 39'. The magnet 39' can be a rare earth magnet or
an electromagnet and, preferably, is encapsula-ted in plastic.
The sensor or transducer is fixed to the support 33 as shown at
9" and it produces signals in relation to the magnitude of dis-
placement of the magnet 39' along the support. The signals from
sensor 9" are digitized and are fed to the storage 24 in the
embodiment of the operating system as shown in Fig. 3. The light
source 6' is also curved to conform -to the dental arch.
In operation, the magnet 39' is displaced along the
support 33 and the sensor 9" produces ou-tput signals related to
the position of the magnet 39' from the sensor 9". The detector
3' receives -the light beam after passage through the tooth-jaw
structure 1 and these are fed to sample/hold amplifier 21 in
the system shown in Fig. 3. The output display gives values
of the tooth width and the interdental spacing after data pro-
cessing.
In Figs. 4 and 5, the Hall effect device and magnet inter-
relate in a head-on mode. The Hall effect device may also be con-
figured in a slide-by mode in relation to the magnet. In other
variations of these embodiments, more than one magnet may be employed
with a sensor or more than one Hall effect device may be used with
a magnet. In order to secure the unit in a stationary position
against the jaw structure, soft positioners 32 can be provided at
the ends of the support 33 in order to hold the unit in a stationary
bearing position against the tooth-jaw structure 1. As an alternate
arrangement, the unit 3' can be secured in fixed relation in
respect to the infant under test in any other suitable fashion.
Figs. 6 and 7 show another embodiment of a linear trans-
ducer and this operates to produce an electrical output proportional
to the displacement of a movable core 40 within a housing 41
containing a primary coil 42 and two secondary coils 43 symmetrically
placed with respect to the primary coil 42. The core 40 serves
as a free moving magnetic core inside the co:il assembly to provide
a path for the magnetic flux linking the coils. Therefore, the
net output of the transducer is the difference between -the voltages
induced in the secondary coils which is zero when the core is at
the center or null position. When the core is moved from the
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null position, the induced voltage ln the coil toward which the
core i9 moved increases while the induced voltage in the opposite
coil decreases. Thls action produces a differential voltage ou-t-
put that varies linearly with changes in core position. The phase
of this output voltage changes abruptly by 180 as the core is
moved from one side of the null position to the other.
In operation, the di.splacement of the core 40 therefore
can be an indication of the linear displacement of the transducer.
The photodetector 8" is secured to the core and travels within
a slot 44 in the housing. As an alternative to the formation of
a slot, the photodetector 8" could be e~ternally connected to the
core to either of the opened ends of the housing whereby the
housing and its coils can remain intact. The optical source 6" is
linearly arranged parallel to the transducer composed of the core
40 and housing 41. In operation, the photodetector 8" is displaced
along the housing which is, itself, integrated with the unit 3"
so that the photodetector 8" will receive the beam of light from
the light source (in this case, a plane of light) after it has
passed through the -tooth-jaw structure 1 and has been altered by
the unerupted teeth D,E,F,G. The signals from the linear trans-
ducer are fed to the operating system shown in Fig. 3 and an out-
put will be produced to indicate the values of the width of the
unerupted -~eeth and the tooth spacing after date processing.
Such a transducer as shown in Figs. 6 and 7 is currently
available from the Schaevitz Company and is designated as an LVDT
linear transducer. Advantages of the use of this transducer in
its standard forms are that the photodetector can adjustably trace
the transilluminated contour outline of the gums and relative
positioning of the portions of the unerupted teeth of interest,
extremely high linearity, and long part life.
A further embodiment is shown in Fig. 8 and comprises a
measuring system which includes a Mitutoyo series 543 Digimatic
Indicator 45 which measures displacement by a photoelectric
encoder. The indicator 45 produces a digital output which is fed
to a Mitutoyo series 264 Digimatic Mini-Processor 46 having a
remote switch jack a7 for initiating a prin-ting operation. The
measurement of tooth width and interdental spacing is accomplished
by having an intecrral light source 6''' preferably of the fiber
optic autoclavable type, and an integral photodetector 8''' which
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is preferably a Vactec VTB 9413B blue-enhanced ulta-high dark
resistance photodiode. The signal Erom said photodiode is connected
to an isolation amplifier transimpedance circuit using a suitable
isolation ampliEier 48. The output voltage oE this circuit is
connected to a window comparator 49 preferably a Burr-Brown
model 4115/04 the "go" output of which is connected to the coil of
a suitable relay 51 having normally open contacts and in turn
connected to the remote switch jack 47 of Mini-Processor 46. By
setting the upper and lower cutoffs of the window comparator 49,
the positions of the tooth edges are printed out on the Mini-
Processor 46 since the anatomical crest at the side oE a tooth
is thinner than the rest of the tooth. A brief pause in advancing
the photodetector 8''' may be needed to allow the printer of the
Mini-Processor 46 sufficient time to reset itself between printing
out values. The desired measurements are obtained by manually
subtracting each adjoining number, or the subtractlons could be
obtained automatically by interfacing the output of the Digimatic
Indicator 45 and window comparator 49 to a suitably programmed
computer. The association of the calculated differences with the
corresponding dimensions of the teeth and interdental spaces are
easily deduced by the operator based on the sequence in which they
were scanned and by the fact that the interdental spaces are much
smaller than the teeth, or if the computer were informed of the
scanning sequence it would make the assignments under program
control. An advantage of this embodiment is that no zero position
need be set for the distance measurements and no distance cali-
bration is required. Furthermore, aside from the need to scan at
the level of the widest portion of each tooth of interest, the
operator is relieved from performing manual measurements which
require careful alignment. In operation, suitable power supplies
are provided, as needed; potentiometers can be used to set the
upper and lower voltage cutoffs needed to detect the edge of a
tooth of a particular infant being examined.
It should be clear that the above technique requires that
the body of the Digimatic Indicator 45 must be stationary with
respect to the infant's upper gums. This may be accomplished by
placing the Digimatic Indicator ~5 in a Mi-tutoyo 213-103P
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~.i'
~Z~S9Z06
Universal Magnetic Stand 50 and the subject's head may be s-tabi-
lized with straps from an infant restraining board and the head
may be further immobilized between the palms of the hands by an
assistant, who may at the same time deflect the upper lip away
from the gums with two fingers at the corners of the mouth.
Ano-ther variation of the above embodiment of the invention
is to connect a Mitutoyo series 542-323 linear c3age -to a Mitu-toyo
332-121 Optoeye Al that has an integral light source and photo-
detector mounted on the spindle of -the linear gage. ~ suitable
power source is provided and the above means for stabilizing
components and the subject are effected to avoid the effects
of unwanted movements upon the measurements.
Referring again -to Fig. 9 therein is seen a feedback
system controllincJ inEant feecling on the basis of input data and
control signals. As shown in Fig. 9, -the infan-t is monitored
initially for age and body length and these values are fed to the
computer which incorporates a real time clock calendar and sub-
programs of parameters previously described in detail to determine:
body length percentile
theoretical length percentile
growth discrepancy risk
feeding requirement for concordant growth.
A controller ls connected to the computer for receiving
signals therefrom and the controller can directly regulate the
feeding of the infant by controlling the flow rate in a feeding
tube connected to the infant or the controller can provide updated
schedules for manual feeding of the infant by breast or bottle
feeding.
In this way the calorie intake of the infant can be con-
trolled in accordance with the parameters furnished by the sensors
or analyzers so that the growth of primary dentition is regulated
to provide desired interdental spacing or too-th-jaw concordance.
Although the invention has been described in relation to
a number of embodiments thereof, it will become apparent to those
skilled in the art -that numerous modifications and variations
can be made within -the scope and spirit of the invention as
defined in the attached claims.
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5~2 D6
For example, in connection wi-th -the preferred embodiments,
the outpu-t of a custom-match window comparator may directly act
as a power source to drive the mini processor/printer, whose
remote switch is kept normally c].osed, thus eliminating the need
for a relay and a separate power supply for the mini/processor
printer.
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