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Description  |
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This invention relates generally to X-ray apparatus and techniques; more
particularly, it concerns method and equipment enabling rapid X-ray
examination of teeth, with substantially reduced exposure to radiation.
Present systems of X-ray examination of human teeth require twelve to
fourteen exposures, accompanied by objectionably excessive amounts of side
radiation to sensitive areas of the brain, cortex, sinus, throat, optic
and auditory nerve centers. Recently, a technique has been proposed
according to which an X-ray target is introduced into the mouth, and
radiation is directed from the target back through the teeth to film
supported outside the mouth, thereby to produce a so-called high
resolution, panoramic radiograph. One problem encountered with that type
equipment concerns the tendency to produce gagging of the patient, due to
the necessity of locating the target sufficiently close to the throat that
back teeth will be exposed to produced X-rays. Another problem has to do
with the requirement that the upper and lower teeth be alternately exposed
to radiation, which in turn requires that the shield associated with the
target be re-arranged. This means that the target is removed from the oral
cavity after the first exposure (as for example irradiation of the upper
teeth, after which the target is re-introduced to enable the second
exposure (of the lower teeth) which increases the risk of gagging and
otherwise discomforts the patient.
SUMMARY OF THE INVENTION
It is a major object of the invention to provide improvements in technique
and apparatus which will overcome the above objects and disadvantages.
Another object is to provide intra-oral X-ray equipment wherein a ceramic
window is provided in a tubular carrier for passing X-rays, and in such
manner that improved, higher clarity tooth images will be produced on
film.
Basically, the invention is embodied in apparatus that includes:
A. X-ray tube means for providing an electron beam,
B. a target for said beam, and
C. a carrier for said target and locating the target in longitudinally
spaced relation from said means to be received rearwardly into a patient's
mouth,
D. said carrier defining a tubular X-ray shield, and there being a ceramic
element defining an X-ray window carried by the carrier and positioned to
sidewardly laterally pass X-rays emanating from the target.
As will be seen, the window cooperates with the X-ray shield defined by the
carrier, and in one form of the invention the window and shield are
tubular and coaxial. In addition, an auxiliary semicylindrical X-ray
shield may be located to extend around the ceramic element and to define
certain boundaries for X-rays passing through the window. Another such
boundary may be defined by a sleeve extending about and positioning a
portion of the ceramic element and carrier.
A further important object of the invention is to provide a ceramic window
cooperating with an X-ray shielding and tongue suppressor means carried to
be received into the patient's mouth, and characterized in that when the
target is located at one side of the mouth to direct an X-ray beam passing
through the ceramic window and toward teeth at the opposite side of the
mouth, the shielding and tongue suppressor means will protect portions of
the head from the X-ray beam and the patient's tongue will be suppressed
relative to the X-ray beam. As will appear, the apparatus may include a
tubular carrier for the target projecting rearwardly of the X-ray tube
itself, and the shielding and tongue suppressor means may advantageously
comprise a component having a base defining an opening removably receiving
the tubular carrier and ceramic element; further, that component may have
arms which project sidewardly of the base with V-shaped configuration, the
lower arm extending sufficiently downwardly and sidewardly as to suppress
the patient's tongue when the base is received between the patient's upper
and lower molars. In this regard, the referenced component may consist of
plastic material containing X-ray shielding substance, as for example
barium; and it may carry upper and lower projections to fit adjacent the
outersides of the patient's upper and lower molars for positioning
purposes, and so that the molars may clench the component to position it
for tongue suppression and shielding orientation relative to the mouth and
head of the patient; also a longer source to film distance is enabled.
These and other objects and advantages of the invention, as well as the
details of illustrative embodiments, will be more fully understood from
the following description and drawings in which:
DRAWING DESCRIPTION
FIG. 1 is a perspective showing of high voltage generator equipment and
X-ray tube mobile or floor mount associated with the invention;
FIG. 2 is a cross sectional view of gun and target apparatus embodying the
invention;
FIG. 3 is a perspective showing of an alternative X-ray tube ceiling or
wall mounting;
FIGS. 4 and 5 are top plan views of gun and target relationships, in
schematic form;
FIG. 6 is an enlarged frontal view of the target and shield;
FIG. 7 is a view like FIG. 4 in FIG. 5, but showing an alternative target;
and FIG. 8 shows another target;
FIG. 7a is a section taken on lines 7a--7a of FIG. 7;
FIG. 9 is a view like FIG. 5, showing modified apparatus wherein the target
is located at one side of the patient's mouth;
FIG. 10 is a perspective view of an X-ray shield and tube positioning
tongue suppressor attachment;
FIG. 11 is a vertical section taken through a patient's mouth showing use
of the FIG. 10 attachment in conjunction with an X-ray tube, target and
carrier as for example is shown in FIG. 9;
FIG. 12 is a plan view of a carrier for an X-ray producing target, and
showing a filter on the carrier;
FIG. 13 is a cross-section taken on lines 13--13 of FIG. 12;
FIG. 14 is a side elevation showing an attachment for the FIG. 9 apparatus,
enabling its use externally of the patient's mouth:
FIG. 15 is a plan view taken on lines 15--15 of FIG. 14;
FIG. 16 is an elevation taken on lines 16--16 of FIG. 14;
FIG. 17 is a perspective view of means to delineate a head zone to be
irradiated;
FIG. 18 is a side elevation view of further modified intra-oral X-ray tube
apparatus;
FIG. 19 is a top plan view on lines 19--19 of FIG. 18;
FIG. 20 is an end view on lines 20--20 of FIG. 18;
FIG. 21 is a view like FIG. 20, with a shield and tongue suppressor
attachment;
FIG. 22 is a side elevation showing still further modified intra-oral X-ray
tube apparatus;
FIG. 23 is a section on lines 23--23 of FIG. 22;
FIGS. 24 and 25 are views like FIG. 11, showing modified attachments, and
FIG. 26 is a view like FIG. 12, showing another modified attachment.
DETAILED DESCRIPTION
Referring first to FIG. 1, X-ray apparatus 10 includes a high voltage
generator console 11 to which X-ray tube 12 is electrically connected, as
via cable 13. A suitable adjustable support for the tube 12 includes
upright post 14 carried by the console; an arm 15 adjustably attached at
16 to the post to rotate about a vertical axis; and a mount 17 for the
tube apparatus and adjustably attached at 18 to the arm 15 to rotate or
swivel about a horizontal axis.
Extending the description to FIG. 2, the tube means 12 includes a housing
19 containing the micro-focus X-ray tube 20 which produces an electron
beam 21. A beam target 23 is carried by the tube means and is located
axially rearwardly thereof (relative to the patient's head 22) to be
inserted or received relatively rearwardly into the patient's mouth. The
forward and rearward axis appears at 36. In the example shown, the target
23 is carried by the rearward end portion of a rearwardly axially
elongated tubular element 24 projecting into the patient's mouth. The
cable 13 is attached to the housing at 26, and passes through an insulator
27 to the gun 20a. The inner conductor of the cable is at high potential
while the outer cable sheath is at ground potential and is solidly
connected to the tube housing. The tube anode is also at ground potential
and only the electron gun 20a is at high potential, insulated by gas or
oil inside the tube housing. This provides the necessary electrically
shock-proof mounting for intra-oral radiography.
An alternative ceiling mount for the tube 112 in FIG. 3 includes an upright
post 114 affixed to or carried by the ceiling of a room. Elements 115-118
correspond to elements 15-18 in FIG. 1.
The target 23 may consist of tungsten embedded in a copper shield 31, the
latter having upper and lower rearwardly tapering surfaces 80 and 81 which
define an angle .alpha. therebetween. That angle subtends a zone which
encompasses the patient's upper and lower teeth (including root areas)
indicated at 32 and 33, but not including the brain or sinus area, the
latter as well as the throat being protected from radiation impingement.
In this regard, an X-ray film holder 34 is carried by the apparatus 12 to
extend at the front of the patient's mouth, and to overlap his cheeks at
opposite sides of the mouth. The film holder is also substantially
subtended by the angle .alpha.. Alternatively, the film may be held in
place against the patient's face as by an elastic strap wrapped around his
head, or the strap may incorporate VELCRO holding means. The target and
shield are carried by the anode envelope 35 which is in turn carried by
the tubular element 24. The anode envelope material is a low X-ray
absorbtion material such as beryllium, titanium, aluminum, aluminum oxide
and beryllium oxide and forms the window for radiation emission.
Extending the description to FIG. 4, the tube anode 37 is shown axially
rearwardly of the gun 20a. The target 23, located axially rearwardly of
the anode, has surfaces 23a and 23b angled rearwardly and transversely
(i.e. sidewardly) relative to the axis 36. Surfaces 23a and 23b are
transversely symmetrical relative to axis 36, and taper axially forwardly,
as shown, at angles .beta. relative to an upright plane 39 normal to axis
36; angle .beta. may for example be about 20.degree..
In accordance with an important aspect of the invention, means is provided
to effect transverse shifting of the radiation pattern produced in
response to beam incidence on the target. Such means may comprise a magnet
supported to be shifted transversely to deflect the beam transversely
relative to the target; for example, FIG. 4 shows the magnet 40 suitably
supported at 41 by the tube at the right side of the axis 36, and
rearwardly of the anode 37, the magnet acting to deflect the beam 21
transversely rightwardly so that it impinges on surface 23a. As a result,
X-rays are produced to travel forwardly through the upper and lower teeth
at the right side of the patient's mouth and to the film in holder 34,
such teeth indicated at 44. Actually, radiation may extend transversely
over the 180.degree. angle indicated, and defined by the plane of surface
23a, and the shield does not interrupt such sideward radiation. See in
this regard the shield openings 45 at opposite sides of the target, in
FIG. 6. Accordingly, the shield has sections 31a and 31b above and below
the target.
Upon completion of exposure of the right side teeth 44 to X-radiation, the
magnet 40 is transversely shifted to the left side of axis 36, i.e. to a
position as for example appears in FIG. 5. In that position, suitably
supported at 41a by the tube, the magnet acts to deflect the beam 21
transversely leftwardly, so that it impinges on target left surface 23b.
As a result, X-rays are produced to travel forwardly through the patient's
upper and lower teeth at the left side of the mouth, and to the film in
the holder 34, such teeth indicated at 44a. Here again, radiation may
extend transversely over the 180.degree. angle indicated and defined by
the plane of surface 23b. The shield does not interrupt such sideward
radiation, but does limit radiation in upper and lower directions, to
remain within the angle .alpha. previously described.
Holders 41 and 41a may suitably releasably retain the magnet, as by
detents. If desired, the magnet 40 may be rotatably carried to swing about
axis 36 between the positions seen in FIGS. 4 and 5.
FIG. 7 shows an alternative means to effect transverse shifting of the
X-ray pattern with a fixed target, seen in FIG. 8. In this view, the tube
12 and supported target 70 are rotatable about axis 136 between the solid
line and broken line target surface positions shown at 50 and 50a. For
example, in FIG. 1 the mount 17 may incorporate means rotatably support
the tube 12 to rotate about axis 136. A sidewardly projecting handle to
rotate the tube 180.degree. outside the mouth appears at 160. A tube
position locking toggle appears at 161. In target position 50, the
operation corresponds to that described in FIG. 4; whereas in target
position 50a, the operation corresponds to that described in connection
with FIG. 5. Envelope 135 and support element 124 correspond to items 35
and 24 in FIG. 2.
FIG. 8 shows the modified tungsten target 70 supported by shield 71, the
latter projecting forwardly at 71a sidewardly of the target to block X-ray
sideward travel and confine same to the region 72. The latter is related
to teeth 144 at one side of the mouth, as shown. Portions of the copper
shield 71 not shown extend above and below the target and forwardly as in
FIG. 6, so that a side opening is formed at only one side of the target.
Target 70 and shield 71 rotate with the tube, as explained above.
Finally, it should be pointed out that since the X-ray intensity necessary
for the required film density is proportional to the square of the
focus-to-film distance, the radiation output of the X-ray source at 5cm
need be only 1/25 or 4% of that required at 25cm with the conventional
extra-oral X-ray tube distance.
The wide-angle radiation pattern of the present tube can expose a panoramic
view of half the mouth including upper and lower teeth in one exposure, so
that only two X-ray pictures are necessary instead of 12 with conventional
extra-oral tubes. When this correction 1/6 is included in the 4% noted
above, the total reduction in radiation amounts to only 0.66% of that
required with conventional dental radiography for the same visual
information. This is a very significant reduction in radiation dosage
which is less than 1% of the present radiation level for whole-mouth
dental radiography.
Referring to FIG. 9, the modified apparatus 100 includes an X-ray tube
means 101, and a target 102 spaced from the tube to be received rearwardly
into a patient's mouth. A tubular carrier element 103 for the target is
attached to the tube means as at 104 and projects rearwardly. The target
may be supported by a shield 105 similar to shield 71 described above. It
is carried by the carrier tube 103 and projects forwardly at 105a
sidewardly of the target to block X-ray sideward travel in the direction
106 and confine X-ray travel to the region designated at 107. The latter
is related to teeth 108 at one side of the mouth, as shown. Portions of
the shield extend above and below the target (as in FIG. 7a) and forwardly
of the target as at 105h, so that a side opening is formed at only one
side of the target. The target and shield rotate with the carrier probe or
tube 103, and a window 109 is formed in the latter to pass X-rays. With
the 30.degree. target oriented as shown, and between upper and lower
molars at one side of the mouth, the sidewardly directed wide angle X-ray
beam at 107 traverses all the upper and lower teeth 110 at the opposite
side of the mouth, a film 111 being located outside or inside the mouth
and proximate teeth 110 for exposure to the X-radiation and recordation of
tooth and gum images. Accordingly, only two exposures are needed to record
images of all teeth, one exposure as illustrated, and an opposite side
(mirror image) exposure with the target located proximate the molars at
the opposite side of the mouth and directing X-rays rightwardly.
Referring to FIGS. 10 and 11, the elements 100-105 and 109 remain as in
FIG. 9; however, additional and very important structure is provided,
namely, X-ray shielding and tongue suppressor means carried by the
apparatus to be received into the patient's mouth and characterized in
that when the target is located at one side of the mouth to direct an
X-ray beam toward teeth at the opposite side of the mouth the shield will
protect portions of the mouth from the X-ray beam and the patient's tongue
will be suppressed relative to the X-ray beam. While such apparatus may
take various forms, that form as illustrated by component 112 in FIGS. 10
and 11 is of unusual advantage. It includes a base 113 which is rearwardly
lengthwise elongated and forms an elongated opening or semi-circular bore
114 sized to snugly receive the tube 103, i.e. with frictional or other
(such as tongue and groove at 213) interfit resisting relative rotation of
the component 112 and tube 103. Preferably, the component 112 has
removable attachment to the tube 103, for ready replacement by another
component for use with a different patient. Thus, component 112 may be
dispensible, and provides a new, sterile hygienic cover for the tube 103
for each use. Tube 103 may consist of copper or Monel, and have a titanium
window 214 to pass radiation.
The component 112 also typically includes arms projecting sidewardly from
the C-shaped base 113 with V-shaped relative configuration, the radiation
passing between the arms. As illustrated, the lower arm 116 extends
downwardly and sidewardly sufficiently to extend centrally over the
patient's tongue 117 to forcibly suppress same out of the main path of the
radiation beam, the vertical path of which may sweep an arc such as at
107a in FIG. 11. Note the edge 116a of arm 116 over the center of the
tongue, with base 113 clenched between the patient's upper and lower
molars 119 and 120 at one side of the mouth (the right side, as also
related to FIG. 9). Therefore, component 112 also acts to position tube
103. The upper arm 118 typically extends upwardly and sidewarldly toward
the root area of the upper molars 121 at the opposite side of the mouth,
and in this regard, arm 116 typically extends toward the root area of
molars 122. The two arms also function as shields to prevent X-ray travel
outside the path or arc 107a, i.e. protecting the palate and below tongue
areas of the head, containing sensitive gland, sinus and brain zones. The
X-ray paths 107 and 107a may include the temporo-mandibular joint.
The component 112 may advantageously consist of plastic material (such as
polyethylene) containing X-ray shielding material, as for example barium
particles dispersed throughout the plastic in as-molded or formed
condition. Other shield substances and component compositions may be
utilized. Coning of the beam to enhance the radiograph is also provided by
component 112 including arms 116 and 118; i.e. beam "scatter" is reduced
or eliminated.
In the mode of use as illustrated in FIGS. 9 and 11, with a substantially
longer source-to-image distance than is characteristic of FIG. 4 use, the
magnification, distortion and geometric unsharpness are all reduced to
improve the overall resolution of the X-ray beam.
FIG. 11 also illustrates the provision of upper and lower integral
projections or tabs 125 and 126 on the component 112, to engage the
outersides of the posterior molars as shown. They aid in positioning the
component relative to the molars when the patient bites down into the
outer surfaces 127 and 128 of the component. Pockets are formed between
the lengthwise extending tabs 125 and 126 and arms 116 and 118, to receive
and locate the molars, during bite-down, firmly locating the arms 116 and
118.
FIGS. 12 and 13 show the provision of an additional X-ray filter 129
extending over the tube 103. Tubular filter 129 may consist of aluminum or
other shielding material. The filter may form a window to register with
window 109.
FIGS. 14-16 illustrate the use of an extra-oral source adapter removably
carried by the tube 103. The adapter structure 130 typically projects
sidwardly of the carrier tube 103 and target 102, and is located to pass
an X-ray beam sidewardly from the target toward a patient's anatomy, and
exteriorly thereof. For example, the structure may be placed against the
cheek area 131 adjacent the teeth, the X-ray film then being located
inside the mouth in a conventional manner. The structure 130 may include a
support cylinder 132 removably slipped onto or over the tube 103, and
suitably secured to the X-ray tube housing, as at 133. The latter may
include a bracket 134 which encompasses the housing 19 and may be clamped
thereto as by tightening screw 135.
The structure 130 includes beam collimator means defined by plastic
cylinder 136 and internal metallic tubular shield 137. These elements
extend generally coaxially with respect to the axis 138 of the X-ray beam
embraced by arc 140. Element 136 projects further from the cylinder 132
than element 137, and both tend to limit the beam to a narrow cone
circumscribing the rectangular periapical X-ray film used in conventional
extra-oral radiography.
Among the advantages of the above apparatus are the following:
1. Increased magnification of the tooth area facilitates diagnosis; for
example, detection of pulp in the root area is made easier, and the
results of grinding of teeth show up more clearly. Thus, the dentist can
more accurately inform the patient of grinding and the deleterious results
of same including possible injury to the jaw hings joint. Splintering of
teeth is also more easily detectable, and sinus areas can be X-rayed to
show up more clearly.
2. The depression of the tongue prevents obscuration of the film.
3. The probe is positioned by the component 112 for obtaining a properly
aligned radiograph, eliminating need for repetitive re-taking of
radiographs, eliminating aggravation and irritability of a patient. Coning
of the beam is also achieved, to enhance the radiograph.
4. The side-to-side interior X-ray technique enabled by the invention
facilitates rapid taking of full mouth X-rays, using only two exposures,
which in turn facilitates accurate charting of teeth by the dentist. Also,
the patient can be shown the full X-ray picture, and can easily see what
dental work needs to be done, so that communication between dentist and
patient is improved.
5. The invention used for panoramic radiographs reduces need for
conventional bite-wings and their holders inserted into the mouth,
obviating discomfort and injury that can result from these items.
6. The probe itself (target and carrier) can be used in emergencies such as
accidents wherein patients undergo severe facial injury, so as to secure
pictures of the extent of that injury. Also, information highly useful for
plastic surgery can be easily obtained.
7. Irradiation of sensitive areas of the brain, optic nerve, thalmus and
thyroid glands is avoided.
8. Full X-ray data, obtainable through use of the invention, is easily
obtained for use as best evidence in legal proceedings.
Finally, FIG. 17 illustrates the provision of a support operatively
connected to the above described X-ray tube means, together with other
means carried by the support at a location to project toward the patient's
head an image delineating an area within the main path of the X-ray beam.
As illustrated, such other means typically includes a light source 200
carried by the support arm 201, the latter extending from a mount 202
attached to the X-ray tube housing 19. The light source 200 may be
suitably shielded at 204.
Light refracting structure is located in the path of light transmitted from
the source 200, such structure advantageously taking the form of a double
prism 206 attached to the shield 204, for example, and extending in openly
spaced confronting relation to the component 112. Light projected
downwardly via iris 204a and in the prism, as rays 207 and 208 is
reflected by prism face 209 as rays 207a and 208a, and an upper image 204b
of the iris 204a in the shield may be formed between the rays 207a and
208a as for example on a patient's face. Similarly, light projected
downwardly via the iris as rays 211 and 212 is reflected by prism face 210
as rays 211a and 212a and a lower image 204c of the iris may be formed
between the rays 211a and 212a as on a patient's face. Images 204b and
204c delineate the upper and lower limits of a facial area in the main
path 107 of the X-rays from the target. Accordingly, the technician will
known precisely where to locate the X-ray film adjacent the patient's
face.
Referring now to FIGS. 18-20, the illustrated X-ray tube means for
providing an electron beam along axis 300 includes an X-ray tube 301
contained within housing 302. The tube anode appears at 303, and the
housing is attached to the anode as via O-ring 304 and nut 305 threaded on
the anode at 306 to retain the housing bore portion 302a thereto.
A target for the beam is indicated at 310, and may consist of tungsten. Its
surface 310a is angled to face forwardly and sidewardly, as shown, and it
is supported by an electrically conductive part 311 located rearwardly
thereof. Part 311 and the target are located within an elongated carrier
312 adapted to be received in the patient's mouth. The carrier defines a
tubular X-ray shield, and for that purpose the tubular carrier may consist
of copper. Part 311 is in electrical contact with the carrier at 313 for
grounding of the target; thus, the part may fill carrier bore 312a. Head
311a fits against the end of the carrier to accurately position the
target, axially. The carrier is connected to the anode 303 at 299.
A ceramic element is provided to define an X-ray window carried by the
carrier and positioned to sidewardly laterally pass X-rays emanating from
the target in response to electron beam impingement on the target.
In that form of the invention shown in FIGS. 18-20, the ceramic window 313
is located in a side-opening or cut-out 314 formed in tubular shield or
carrier 312, and it may be peripherally brazed in position as shown at
315. The window is laterally arcuately curved to match the curvature of
the tubular shield, and it has longitudinally spaced, laterally extending
edges at 313a and 313b, as well as circularly spaced, longitudinally
extending edges 313c and 313d. Such edges or boundaries define the shape
of the cone of X-radiation passed by the window. Edge 313b laterally
overlaps the target, as shown in FIG. 19. The use of a ceramic window is
found to result in very clear, X-ray produced images of teeth, on film
located as previously described. The window may be of uniform radial
thickness.
FIG. 21 shows the X-ray shielding and tongue suppressor means 320
(corresponding to that described earlier at 112) carried by the shield
312, with a side opening 321 in lateral registration with window 313. Side
opening 321 is formed between laterally diverging arms 322 having
laterally diverging interior surfaces as shown. A keyway or other guide
shoulders at 323 provide a longitudinal interfit between the carrier 312
and the base 324 of the attachable means 320 to assure proper lateral
registration of opening 321 with the ceramic window. The ceramic window is
thus a cylindrical segment having rounded corners at 350.
Turning to FIGS. 22 and 23, the modified ceramic element 330 forms a
complete cylinder and is held in coaxial end-to-end relation with the
tubular shield or carrier 331, which may likewise consist of copper. For
example, a thin metallic (nickel) sleeve 332 may extend closely about and
position tubular portions of the shield 331 and ceramic element 330. In
this case, the sleeve portion 332a overlapping the ceramic element defines
an X-ray shield and a boundary of the window to limit the X-ray cone at
locus 333. Another and like sleeve 334 fits over the opposite end portion
of the ceramic element to limit the X-ray cone at 335. A metallic ring
336, as for example copper, fits within the sleeve 334 and is joined
thereto in spaced relation to the ceramic element, and the electrically
conducting support 337 for the target 338 is received within the ring 336
and the ceramic tube, as shown.
An auxiliary, semi-cylindrical X-ray shield 339 extends partly about
ceramic element 330 and about the sleeves 332 and 334 to establish an
electrically conductive grounding path between the target, part 337,
sleeves 334 and 332, carrier tube 331 and the anode 303. Shield 339 has
longitudinal edges 339a and 339b which establish boundaries 340 and 341
for X-rays passing through the window. The cone angle between the
boundaries 340 and 341 is typically about 45.degree., whereas the cone
angle between boundaries 333 and 335 is typically about 75.degree..
The shield 339 may consist of lead, and usable ceramic compositions for
tube 330 and window 313 include the following examples, others being
possible:
______________________________________
I
beryllium oxide about 90%,
by weight
silicon dioxide about 7% "
impurities
(clays, magnesium etc.)
balance "
II
aluminum oxide about 90% "
silicon dioxide about 7% "
impurities (see above)
balance "
______________________________________
Referring to FIG. 24, it shows a ceramic tubular element 430, like element
330 in FIG. 22, onto which an element positioning, X-ray shielding, tongue
suppressing means 420 is received. The means 420 corresponds to that
described at 320 in FIG. 21, excepting that the ears or tabs 421 are
located out of alignment with the tubular element 430. Molars 422 and 423
are in alignment with the tube, and are received in pockets 424 formed by
the means 420. FIG. 25 is similar, excepting in this case, the tabs 421a
on modified means 420a are sufficiently spaced from and at the outer side
of the tube 430a that the latter is positioned at the inner sides of the
molars 422a and 423a. Positioning of the tubes by the means 420 and 420a
eliminates need for repetitive re-taking of radiographs, reducing or
eliminating aggravations and irritation of the patient.
In FIG. 26 the tube positioning, X-ray shielding, tongue suppressing means
512 corresponds to means 112 of FIG. 10; however, stem 513 is annularly
flared at its end 513a to fit over the end 520 of the tube housing. As a
result, a patient's mouth does not come into contact with the tube or its
housing, and the stem 513 acts as a sterile cover for the tube and
housing. Elements 518 and 525 correspond to elements 118 and 125 in FIG.
10.
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