Ocular prosthesis
1. The eye was a symbol of life to the ancient world,
particularly in Egypt, where bronze and precious stone eyes were placed on the
deceased. The Romans decorated statues
with artificial eyes made of silver. history
2. Ambrose Paré
(1510-1590), a famous French surgeon, was the first to describe the use of
artificial eyes to fit an eye socket. These pieces were made of gold and
silver.
3. Enamel prostheses
(1820s-1890s) were attractive but were expensive and not very durable. The introduction of cryolite glass, made of
arsenic oxide and cryolite from sodium-aluminum fluoride (Na6A2F12), produced a
grayish- white color suitable for a prosthetic eye.German craftsmen are
credited with this invention in 1835.
4. To make these
glass eyes, a tube of glass was heated on one end until the form of a ball was
obtained. Various colors of glass were used like paintbrushes to imitate the
natural color of the eye The glass art
form flourished in France and Germany where fabricating secrets were handed
down from one generation to the next.
5. The town of
Lausche, Germany, had a particularly rich history in both decorative (doll
eyes, Christmas ornaments) and prosthetic arts. In the 19th century, German craftsmen
("ocularists") began to tour the United States and other parts of the
world, fabricated eyes and fit them to patients.
6. Stock eyes (or
pre-made eyes) were also utilized. An "eye doctor" might keep
hundreds of glass stock eyes in cabinets, and would fit patients with the best
eye right out of the drawer.
7. In the United
States, eyes continued to be made of glass until the onset of World War II,
when German goods were limited and German glass blowers no longer toured the
United States. The United States
military, along with a few private practitioners, developed a technique of
fabricating prostheses using oil pigments and plastics. Since World War II,
plastic has become the preferred material for the artificial eye in the United
States.
8. By the mid-1940s,
glass eyes were being replaced by plastic counterparts. In Virginia, this was led by Joseph Galeski
(of Richmond, Virginia), Although
American Optical and several military hospitals started to experiment and
dispense plastic artificial eyes.
9. An ocular implant
replaces the lost volume of the natural eye. The first account of placing an
implant in the socket, following enucleation, was in 1841. Implants have been made of many different
materials, shapes, and types throughout the years. It also helps the artificial
eye to have some degree of movement
10. Naval dental school (1940), tested the use of acrylic
resin in fabricating a custom ocular prosthesis. Unlike a glass eye, an acrylic
eye was easy to fit and adjust, unbreakable, inert to ocular fluids, esthetical
good, longer lasting and easier to fabricate
11. Surgical procedures in the removal of an eye are
classified into three categories Evisceration- Removal of the contents of the
globe, but leaving the sclera and sometimes the cornea in place. Because the
extra-ocular muscles are left intact, good mobility of the prosthesis is
usually possible Enucleation- Removal of the eyeball itself Exenteration-
Removal of the entire contents of the orbit, including the extraocular muscles
12. Stock ocular prosthesis Stock acrylic resin eyes are supplied in three
basic shapes: oval, standard and three- cornered. Each shape has three sizes: small, medium and
large, and they may be prepared for the right or the left eye.
13. The irises are
produced in three basic colours: brown, hazel and blue, and the individual
colours have been formulated so that they have some elasticity and overlapping
quality in matching effects. The scleral
colours are also varied.
14. One basic size of
iris (11.5 mm) is used, and it has a pupil opening of 3.5 mm. Where possible, the stock eye should be made
to duplicate as closely as possible the superior fit and aesthetics of the
custom eye.
15. impressions Dental impression materials such as
impression compound, dental waxes, irreversible hydrocolloids ,tissue conditioners
and elastomeric materials have been successfully used to register the
topography of the eye socket
16. Stock tray impression technique: • An impression is made
of the ocular defect using a disposable syringe, stock ocular trays and
irreversible hydrocolloid. •Stock acrylic resin impression trays available in
different sizes for ophthalmic impressions •Trays have a hollow handle which
accomodates an impression syringe
17. During the
procedure ,the patient should be seated in an upright position with the head
tilted backward at app 450 This position allows the natural positioning of the
palpebrae and surrounding tissue relative to the force of gravity.
18. The tray should
be placed into the defect to determine the proper orientation and fit without
overextension. The tray is then removed
and the impression material is loaded in the syringe and sufficient material is
ejected to fill the concavity of the tray.
19. Ophthalmic
irreversible hydroclloid is mixed in a 30 ml medicine cup –app 5 ml of powder
to 5 cc of room temp water. Alginate –
warm ,runny mix flow easily not distort the fatty tissues in the socket
20. The tray is
reinserted and sufficient material is injected to elevate the lid contours
similar to the normal side. once filled
the patient is directed to move their eyes both up and done. After the impression sets the assembly is
removed and examined for defects and voids.
21. L. M. Sykes,Essop, Veres(J Prosthet Dent 1999;82:362-5.)
described a procedure for fabricating
acrylic resin ocular custom-made conformers to maintain socketsize and contour.
These custom-made ocular conformers act
as an interim measure and as valuable diagnostic indicators of problems
experienced by the patients..
22. While stock
conformers merely maintain the socket size and prevent scar tissue
contractures, the custom-made conformers can also be used to enlarge
unfavorably small sockets, stimulate eyelid movement, aid hygiene, help the
clinician develop the final shape for the definitive prosthesis, and reduce the
amount of postinsertion adjustments needed.
23. If further
surgery is needed to deepen the socket bed or alter the eyelids, the socket is
enhanced by using the conformer as a surgical stent to maintain the mucosal
grafts in position and support the fornices.
24. Early settling
and sinking occurs with most patients, so that modifications to their
conformers are required to maintain an esthetic appearance and adequate eyelid
support.
25. These advantages
and the ease of fabrication make custom-made conformers a viable initial
treatment option in patients with ocular defects
26. The presence of
the custom-made conformer and its close approximation to the tissues in the
socket, stimulates the eyelid muscles to move, thus,exercising them and
preventing disuse atrophy. Stock
conformers lack a close fit and therefore cannot stimulate eyelid movement
27. Beumer et al
advocated placing a plastic stock conformer immediately into the socket to fit
the contours of the cavity and to fill the depths of the fornices. These were to be left in place while healing
occurs to reduce edema and to maintain the socket contours for the definitive
prosthesis
28. Anesthetize the
socket with 1 or 2 drops of topical anesthetic Select an ocular special tray of the
appropriate size and try it into the socket to verify the fit.
29. If the special
tray is not available, a tray can be fabricated at the chairside by heating a
small piece of modeling compound and adapting it to the area around the eye or
around a small rubber ball.
30. This should be
kept as thin as possible [2 to 3 mm].) Place a small tube in the center of the
compound and lute it into position with sticky wax. The addition of a few small holes in the wax
aids retention of the impression material.
31. Hydrocolloid
material is mixed to a runny consistency by adding 1.5 parts warm water to 1
part powder. Inject the hydrocolloid
down the tube into the socket under slight pressure while supporting the tray
in position, then allow the impression to set.
32. Remove the
impression and use it to pour a 2- piece split cast mold that is used to
fabricate the acrylic resin conformer. Once fabricated, the conformer can be fitted
immediately and adjusted at the chairside where needed, thus not allowing time
for the socket to shrink and scar tissues to contract.
33. Dismiss the
patient with instructions to wear the conformer continuously and only to be
removed for cleaning. Severe pain or
discomfort must be reported immediately to ensure that necessary adjustments can
be made.
34. Once the
clinician and patient are satisfied with the size and conformity of the
conformer, and the socket is well healed and dimensionally stable, a
conventional, definitive ocular prosthesis can be manufactured. A duplicate of the modified conformer in wax
can be used as a template for the definitive prosthesis
35. Alginate
impression material is expressed into the defect using a disposable syringe. Next a perforated acrylic resin tray is loaded
and placed over the defect. The impression
is first recovered from the lower, shallower sulcus first, then rotated out of
the deeper, upper sulcus. 38 External tray impression technique(Taylor)
36. The impression is
boxed and poured in the dental stone up to the height of contour of the
impression. A separating agent is placed
and the reminder of the impression is poured
37. Engelmier.R.L.Autoclavable custom made metal impression
trays to improve infection control.JPD 1987;58:121-2 Has suggested casting a set of stock trays in
ticonium which is a non precious,removable partial denture alloy (Ticonium Co
,Albany,NY) which can be sterilized in an autoclave for reuse The impression material of choice is
ophthalmic alginate(Ophthalmic Moldite)
38. Ow,Amrith.Use of a tissue conditioner material to modify
a stock ocular prosthesis.JPD 1997;78:218-22 Advocated the use of tissue conditioners as a
reline material because of its bio compatibilty and ease of manipulation. Stock acrylic resin prosthesis is selected and
is modified by trimming its periphery to fit the eye socket
Visogel(Dentsply,England) is added and inserted for 20 mins.
39. Excess material
is removed and the ocular prosthesis is worn for 24-48 hrs If the esthetics and adaptation are acceptable
,the prosthesis is relined with heat cure resin.
40. Smith R M.Relining an ocular prosthesis-A case
report.JPD 1995;4:160-3 Described a
reline procedure for an existing ocular prosthesis The ocular prosthesis is reduced in size until
it fit comfortably in the socket. Melted
base plate wax is added to the borders until the ocular prosthesis is
positioned properly
41. Borders of modified prosthesis are shaped with baseplate
wax until proper gaze is establishcd
42. The lid contours
and gaze were assessed and wax carved or added until the position of the ocular
prosthesis was satisfactory in all dimensions
43. Ocular prosthesis in place after borders are adjusted,
and gaze is established.
44. A thin layer of
Korrecta wax No.4 is added to the intaglio surface and the borders The prosthesis is then dipped into 123 0 F
water bath,inserted and left for 5 mins
45. Ocular prosthesis showing reline impression made with
Korecta-wax
46. During this time,
the patient was directed to take the prosthesis through a full range of motion.
The ocular prosthesis was removed,
inspected for coverage, and wax added in deficient areas or the excess removed
as indicated.
47. The borders and
intaglio surface were covered completely by the Korecta-wax. If there were any show throughs, the underlying
surface was relieved and covered with more wax. Again, the prosthesis was placed and worn for
5 minutes
48. Once the
dimensions are corrected kept in the patients eyes for 30 mins while he moved
it intermittently in all directions A
laboratory reline procedure is then performed .
49. Ocular prosthesis relined with Crystal Clear acqlic
resin.
50. Impression With Custom Ocular Tray Miller suggested that
a custom ocular tray is necessary in certain situations. For example, the
anophthalmic socket could be highly irregular or stock trays may not be
available. Miller BJ: Custom ocular impression trays. J Facial SomatoProsthet
1996;2:109-113
51. Miller’s method
involves attaching a solid suction rod to the patient’s existing prosthesis,
conformer, or wax shell and investing it in an alginate mold. After the alginate sets, the prosthesis,
conformer, or wax is removed and replaced with clear acrylic resin.
52. Perforations are
made in the resulting tray, and a tunnel is cut into the stem through which
impression material can be delivered. An
impression is made using injected alginate.
53. Mark F. Mathews, DDS, Rick M. Smith, DDS, Alan J.
Sutton, DDS,and Ron Hudson .The Ocular Impression: A Review of the Literature
and Presentation of an lternate Technique .JPD December 2000, Volume 9, Number
4 1. The patient’s existing prosthesis or conformer was disinfected and lightly
lubricated
54. 2. Medicine cup was filled with quick set stone
(Whip-Mix Blue Mounting Stone; Whip- MixCorporation, Louisville,KY), and the
tissue side of the prosthesis was invested till the height of contour.
55. 3. When set, the edges of the stone cast were notched. A
small amount of PVS putty (Reprosil Putty; DentsplyInternational Inc, Milford,
DE),was mixed and was adapted over the top of the prosthesis and into the
notched indices. Putty cope,was removed and a large, beveled sprue hole was cut
into its center and a small vent to the side.
56. 4. The prosthesis were removed from the mold, The stone
surface was lubricated (Liquid Tin Foil Substitute; Robert B.Scott, Inc, Tampa,
FL), and the putty cope was replaced.
57. 5.Chemical-cure polymethylmethacrylate (Great Lakes Co,
Chicago, IL),was mixed and poured into the mold .The assembly was placed in a
pressure pot for 20 minutes at 25 psi.
58. 6.The acrylic resin tray was removed, trimed and thined
as needed. The tray was perforated approximate at pupil location with a 3- to
4-mm diameter hole. Multiple perforations were placed over the remainder of the
surface. The custom tray was then polished .
59. The tray was repolished, and checked for rough spots.
Tray was checked for overextension and proper orientation. Now the barrel of
the 5-mL syringe was attached to the injection tube.
60. 3 teaspoons water and 1 tablespoon of ophthalmic
alginate impression material was mixed(Robert B. Scott, Inc), and back loaded
in the syringe. Tray was seated and the alginate was injected. After the
alginate impression material was set, the impression was removed and was
checked for for acceptability
61. When set, the
alginate mold was removed with impression from the cup.The alginate mold was
partially sectioned,and the original impression was retrieved. The different mixes of alginate will not adhere
to each other. The second alginate
impression becomes a mold to form the wax blank. The alginate mold is poured in
the cup,with ivory wax (40/40 Ivory Wax; MDLDental Products Inc, Seattle, WA)
through the sprue hole created by the syringe tip.
62. Upon cooling,the impression is removed from the cup to
retrieve the wax blan.The sprue is cut off, The wax trial ocular prosthesis is
shaped and polished. Try in of the wax trial prosthesis is done to assess fit,
contour, and comfort. The iris button is added to the pattern, and then it is
processed.
63. Formulation of the cast Imp poured in two sections using a 30 ml cup
filled halfway with dental stone .
64. D.stone is added
to the post.surface of the impression and then placed into the cup upto the ant
of the postr edge of the imp and allowed to set . 2 keyways are made ,1 each adjacent to the
region of the nasal and temporal canthus.
65. Stone is coated
with a seperating medium [tin foil substitute] allowed to dry. Second half of the mold is poured with dental
stone leaving a funnel shaped hole around the stem of the tray .
66. The hole used as
a funnel to fill the mold with molten wax . After the d.stone has set ,2 halves of the
mold are separated and the imp material is removed .
67. Wax pattern: The
melted wax is then poured through the funnel shaped hole and into the assembled
mold. Soaking the mold in water for a
few minutes prior to filling it with molten wax will prevent the wax from
adhering to the stone.
68. After the wax has
cooled, the wax pattern is recovered. Once the wax pattern has been smoothed
and polished, it is ready to be tried in the eye socket.
69. To insert the wax pattern, the upper lid is lifted, and
the superior edge of the pattern is placed behind the lid and gently pushed
upward.
70. While drawing the
lower lid down, the inferior border of the pattern is seated in the inferior
fornix, and then the lower lid is released. The eye contours are checked.
Pressure points and areas of discomfort is noted and relieved
71. Iris position The
iris should be bilaterally symmetrical; therefore, accurate placement of the
custom- painted iris disk on the scleral wax pattern is critical. The gaze and the position of the iris is
determined .
72. McArthur RD: Aids for positioning prosthetic eyes in
orbital prosthesis. J Prosthet Dent 1977;37:320-326 McArthur described methods for positioning the
artificial eye in the orbital prosthesis using an ocular locator and fixed
caliper. This determined the placement
of the prosthetic eye in the mediolateral and supero-inferior planes.
73. Benson P: The fitting and fabrication of a custom resin
artificial eye. J Prosthet Dent 1977;38:532-539 Benson suggested a method for fabricating
aBenson suggested a method for fabricating a custom-made acrylic resin ocular
prosthesiscustom-made acrylic resin ocular prosthesis in which he determined
the size and positionin which he determined the size and position of the iris
byof the iris by visual judgment.visual judgment. Because irisBecause iris
positioning is a technique-sensitivepositioning is a technique-sensitive
procedure, visual assessment alone may notprocedure, visual assessment alone
may not be accurate.be accurate.
74. Roberts.A.An instrumeny to achieve pupil alignment in
eye prosthesis.JPD 22;4:1969 Roberts has
suggested the use of aRoberts has suggested the use of a
pupillometerpupillometer for precise alignment of the pupilfor precise
alignment of the pupil in the eye prosthesis. Though the advocatedin the eye
prosthesis. Though the advocated method may be more precise, it may not
bemethod may be more precise, it may not be feasible to use the pupillometer in
everyfeasible to use the pupillometer in every clinical set-upclinical set-up
75. The iris should be bilaterally symmetrical; therefore,
accurate placement of the custom- painted iris disk on the scleral wax pattern
is critical.
76. Satyabodh S. Guttal, Narendra P. Patil. A Simple Method
of Positioning the Iris Disk on a Custom-Made Ocular Prosthesis. A Clinical
Report.JOP ;17: (2008) 223–227 The
transparent graph grid was used in this method to attach the iris disk.
77. During the trial
of the scleral wax pattern, certain guidelines were marked on the patient’s
face with an indelible pencil ,a vertical midline was marked considering the
stable anatomical landmarks and prominent points on the face
78. The midline was
marked passing through the forehead crease, glabella, tip of the nose, and
chin. The distance from the right eye
medial canthus to the midline and left eye medial canthus to the midline was
measured. This distance standardized the
midline marking and was used to reposition the grid template each time during
the try-in visit.
79. The patient was
asked to gaze straight at an object kept 4 feet away. The operator then marked the vertical lines
coinciding with the medial and distal extremities of the iris of natural eye.
80. Similarly, the
horizontal lines referring to the center, inferior, and superior limits of the
iris were marked. The facial markings
were transferred to the grid template by placing it on the patient’s face.
81. Markings were
also made on the transparent grid template, on the X-axis from A through H
starting from the midline, and on the left side A1 to H1; similarly, on the
Y-axis from 1 through 7 and 11 to 71. The distance between each marking was 1 cm on
both X and Y axes.
82. These markings
were transposed onto the side of defect. This can be done either directly on
the patient’s face or on the facial moulage The markings were transferred onto the
sculpted scleral wax pattern, and the iris button attached to the wax pattern
83. The method
described in this article involves a simple procedure for positioning the iris
in a prosthetic eye The accurate
placement of the iris and pupil component in the ocular prosthesis simulated
the conversational gaze
84. Thus, the use of
a transparent grid template helped to accurately locate and position the iris
on the custom-made ocular prosthesis rather than relying purely on the visual
assessment, the latter being subjective with possible interobserver errors
85. Paper Iris Disk Technique When the wax pattern is
determined to be appropriate, it is flasked and processed in scleral resin. The
scleral blank is then finished, and it is polished using pumice and acrylic
resin polish
86. The scleral blank
is tried in and the middle of the pupil is marked while the patient gazes
directly at the clinician. The size of
the iris is measured using a millimeter measurement gauge or optical scale. The outline of the iris is then marked on the
scleral blank using Carmen red ink.
87. This ink will
transfer to the investing stone, facilitating the appropriate placement of the
corneal prominence. The blank is tried
in again to verify the location and size of the iris.
88. The location of the iris will transfer to the investment
and a scraper can then be used to create the corneal prominence of the
prosthesis in the investment
89. A disk of
ordinary artist's watercolor paper is punched out using a die. The size selected should be 1 mm smaller than
the measured size of the iris. This will
allow the iris to appear to be the appropriate size because the corneal
prominence will cause a slight magnification of the iris disk patient's iris.
90. A good selection
of colors for this purpose includes ultra-marine blue, yellow ochre, burnt
sienna, burnt umber, yellow oxide, titanium white. Colors should be mixed and reapplied in a
layering fashion to mimic the colored striations in the patient’s iris.
91. Medial canthus Pupil IRIS ANATOMY
92. Begin by painting
the darkest color, the area toward the outer edge of the iris ring (limbus). The color of the limbus varies from eye to
eye, but it usually is a combination of gray and iris body color.
93. In the natural
eye, it can appear as a shadow from the overlapping sclera, covering the edge
of the cornea. Next the collarette is
painted. It is usually a lighter color
than the body of the iris. A black spot
should be painted in the center of the disk to represent the pupil
94. The diameter
should mimic the natural pupil under indoor light conditions. This will make size appear relatively
appropriate under most conditions.
95. After the paint
has dried, a drop of water is applied to create the magnification of the
corneal prominence and the color matched.
96. Using a flat-end
bur, a flat surface is prepared in the scleral blank for the iris painting. A sprue wax is luted to the prepared flat
surface and tried in.
97. The orientation
of the surface is adjusted until the sprue points directly at the observer
while the patient looks directly into the observer's eye. This will ensure that the prosthesis and the
natural eye will have the same gaze
98. •Using a large abrasive stone, the entire anterior
surface of the scleral blank is reduced at least 1 mm. •The remainder of the
prosthesis is then painted to match the sclera of the natural eye.
99. Fine red
embroidery threads are placed on the scleral painting to mimic the blood
vessels of the patient's natural eye. The entire scleral portion is then coated with
monomer polymer syrup to keep the blood-vessel fibers in place and allowed to
set.
100. Once the monomer-polymer syrup has set, the scleral
blank is replaced into the flask, and the iris painting is placed on the flat
section.
101. Clear ocular
acrylic resin is mixed and placed into the mold space and the flask trial
packed. Once trial packed, the flash is
removed and the location of the painting verified to ensure that it has not
moved during trial packing.
102. BLACK IRIS DISK TECHNIQUE The natural eye is observed closely and the
diameter of the iris is estimated using a millimeter measurement gauge or optical
scale. Ocular discs, which are used in
the iris painting, are available in half- mm sized increments, ranging from 11
mm to 13 mm. 120
103. They come in
black or clear, and either with or without pupil apertures. Clear corneal buttons are available in the
same sizes as the discs. The buttons can
also be purchased with pupils of various sizes already in place.
104. The technique
employed in painting the disk produces a three-dimensional effect. oil pigments
are employed in this technique but are mixed with a monomer-polymer syrup
during the painting process. This mixing
procedure provides some degree of translucency in the iris painting and permits
rapid drying of the pigments
105. The basic eye
color or background color is observed along with the limbus color. The background color is applied to the disk
first, using brush strokes from the center toward the periphery.
106. After the
background color is applied and dried, a coat of the clear syrup is applied and
allowed to dry. Characteristic
striations are applied over the clear layer and allowed to dry. A second clear
layer is then applied and further characterization accomplished
107. After the second
layer is dried, the limbus color is matched around the periphery of the disk
and a third clear layer applied. The
color around the pupil is applied over the last clear layer and the final color
evaluated with the water interface. After a satisfactory color match has been
obtained, a final clear layer is applied and allowed to stand for 15 minutes.
108. A single droplet
of the monomer-polymer syrup is then placed in the center of the iris disk and
the lens button is gently placed and centered. The positioning of the iris-lens assembly on
the wax scleral pattern is the most important phase in fabrication of the
prosthesis.
109. Fix the lens button to the scleral pattern in a manner
such that the apparent gaze of both natural and artificial eyes is on the same
object, or parallel to one another and in the same plane.
110. The size of the
lens assembly selected should be large enough to include the limbus. The lens assembly is placed in a slight
depression in the scleral pattern, and a thin layer of wax should be brought up
over the curvature of the lens assembly.
111. This thin layer
of wax will allow the opaque white scleral acrylic resin to flow up over the
edge curvature of the lens assembly during the packing procedure, forming a
very thin, translucent layer.
112. The finished
pattern is then invested in a small two-piece brass flask. The resulting scleral blank is deflasked,
trimmed, and polished
113. The position and
gaze of the artificial eye is again observed. The sclera is slightly roughened using
sandpaper disks in preparation for adding the simulated vasculature. Rayon-thread fibrils are placed onto the
surface of the sclera using the monomer- polymer syrup.
114. The pattern and
type of vessels ( tortuous, straight, branched) of the opposite eye are
reproduced. The colors found in the
sclera are usually yellow and blue, or combinations of these. Greens and browns
can also be present.
115. The scleral
painting begins with the application of a wash of yellow comparable to that
found on the patient's natural eye. Next, blue is added, which is usually located
inferior and superior to the iris. Finally, any characteristic details present in
the natural eye are added.
116. Once complete, a
coat of monomer and polymer is applied to the sclera. The eye is now ready for the final processing,
the application of a layer of clear acrylic resin
117. The prosthesis is cleaned and placed in socket. The fit
of the artificial eye are evaluated and adjustments are made as necessary.
118. Digital imaging in the fabrication of ocular prostheses
Ioli-Ioanna Artopoulou, DDS, MS,a Patricia C. Montgomery,b Peggy J. Wesley,
CDA,c (J Prosthet Dent 2006;95:327-30.) Using digital imaging in the fabrication of
the ocular prostheses presents several advantages compared to the conventional
oil paint and monopoly iris painting technique
119. The digital
image provides acceptable esthetic results be cause it closely replicates the
patient’s iris with minimal color adjustments and modifications. The described technique is simple, decreases
treatment time, and requires minimal artistic skills, which are necessary in
the iris painting technique .
120. However, special
digital photography equipment and settings, as well as computer software that allows
for image adjustments, are required.
121. Make an
impression of the anophthalmic socket with a stock acrylic resin tray designed
for ophthalmic impressions (Factor II Inc) using the ophthalmic irreversible
hydrocolloid (J-603 Special Formula Alginate; Factor II Inc).
122. Pour a master
cast and fabricate a wax pattern using baseplate wax (Truwax Baseplate Wax;
Dentsply Intl, York, Pa).
123. Evaluate the wax
pattern in the patient, and evaluate and finalize the sculpting following the
eye socket contours and lids configuration
124. Make a digital
photograph of the patient’s iris using a digital camera (Canon EOS Digital
Rebel; Canon Inc, Tokyo, Japan) with a macro lens (Canon Macro Lens EF 100 mm
f/2.8 USM; Canon Inc) and a ring flash (Canon Macro Ring Lite Flash MR-14EX;
Canon Inc) attached. Set the shutter
speed to 125 seconds, the aperture to F 16, and the sensitivity to ISO 640
125. Evaluate the
photograph and compare it to the patient’s iris. Using graphics software (Photoshop 7.0; Adobe Systems Inc, San Jose, Calif),
adjust for slight differences in color, brightness, contrast, or hue, and
format the image.
126. Print the final
image on 20-lb white paper with brightness87 (HP Office; Hewlett- Packard, Palo
Alto, Calif) using a laser printer with a color-ink print cartridge
127. Cover the paper
iris with 3 light coats of water-resistant spray (Workable Fixatif; Krylon,
Solon, Ohio) used for artwork, and attach it to the ocular disk. Use monopoly syrup (J-305 Monopoly
Syrup;Factor II Inc) to position the ocular button (Factor II Inc) on the iris,
and paint around the edges of the button and the disk to achieve maximum seal
128. Ocular button positioned on paper iris using monopoly
syrup
129. Disk assembly attached to wax pattern and ready for
trial insertion
130. Attach the disk
assembly to the wax pattern and evaluate it in the patient. Process the selected scleral acrylic resin at
the same temperatures, using the procedure previously described for the
conventional technique
131. After
characterization is added, reprocess the ocular prosthesis with clear acrylic
(Factor II Inc) using the previously described temperatures. Pumice and polish the completed eye and insert
it
132. COMPLICATIONS IN FITTNG ANOPHTHALMIC SOCKET Ptosis:
Superior eyelid ptosis is a frequent problem in the restoration of an
anophthalmic patient. Pseudoptosis is due to the loss of volume between the
implant and the lids after removal of the eye.
133. If the
physiological function of the eyelids is intact, correction of Pseudoptosis is
achieved by increasing the volume of the prosthesis in the socket. This condition usually occurs whenever a
small, poorly fitted prostheses is used.
134. A simple
technique of correcting Pseudoptosis is to make a larger prosthesis that will
thrust forward and separate the eyelids
135. Persistent ptosis requires modification of the ocular
prosthesis to correct for a deficient levator muscle, which causes the upper
eyelid to droop..
136. Attempts aimed
at increasing the size of the ocular prosthesis, as seen in Pseudoptosis, will
not correct the problem in persistent ptosis. The tension on the superior lid forces the
larger prosthesis downward, thus depressing the lower eyelid, deflecting the
gaze downward and creating patient discomfort
137. A thin transparent shelf can be made across the front
surface of the eye to hold the upper eyelid at the desired open position. The
shelf is 3 to 4 mm wide and is placed along the upper limbus.
138. This
modification of the prosthesis works well for ptosis caused by a superiorly
migrated, large, spherical implant with limited socket space between the
implant and the upper eyelid. The major
drawback to the shelf is that eye cannot blink or close. The weight of the
upper eyelid and the action of the orbicularis muscle may press the eye
downward.
139. This may be corrected by adding material to the
inferior tissue surface of the prosthesis to contour it backward and upward.
The surface above the shelf can be reduced to decrease the weight of the
prosthesis and to create space for a tight upper eyelid.
140. Ectropion: - Inferior displacement of the implant can
lead to the loss of the inferior fornix and cause ectropion of the lower lid.
Patients have difficulty with retention of the prosthesis, since it has a
tendency to slip down and out over the everted lower lid.
141. This is
rectified by extending a thin lower edge that will press downward upon the
tarsus, and rotate it into a more vertical plane, thus creating a lower fornix.
142. The lower edge
should be rounded and at least 1 mm in thickness so it will not cut into the
socket. The lower fornix will deepen
within minutes of modification, and insertion of the prosthesis and retention
will improve
143. Sagging lower eyelid: The weight of the prosthesis, and
the contraction force of the upper eyelid on the prosthesis can cause a
downward displacement of the lower eyelid, causing it to droop.
144. Degenerative disease may also weaken the lower eyelid,
causing it to droop. By removing resin from the mid inferior margin of the
prosthesis, downward pressure against the middle of the lower fornix is
relieved.
145. Wax is added to
extend the nasal and temporal aspects of the inferior margin to create pressure
in the medial and lateral areas of the lid. This directs the weight of the prosthesis
where the lower eyelid is strongest, near the palpebral ligaments. These
modifications tilt the tarsus of the lower eyelid favorably so that the eyelid
margin is elevated.
146. Ocular implants are classified as 1. Integrated 2. Semi
- integrated 3. Non-integrated and 1. Buried or 2. Non-buried
147. Integrated
implants are designed to improve prosthesis motility by coupling to the
overlying prosthesis. Implants is exposed through the conjunctiva to be
directly coupled to the prosthesis with a peg, pin, screw or other method.
148. Semi-integrated ocular implants consist of an acrylic
resin implant with 4 protruding mounds on the anterior surface. These acrylic
resin mounds on the implant protrude against the encapsulating tissue. When an
ocular prosthesis is made, a counter contour to the implant is formed on the
posterior surface of the prosthesis. Nonintegrated implant This is done by
placing a hollow or solid acrylic resin sphere ranging from 10 to 22mm in
diameter.
149. The placement of an orbital implant into an enucleated
socket was first described by Frost in 1886
150. Soil described
an improved surgical method of placing the orbital implant deep within the
muscle cone, and buried beneath the posterior layer of Tenon’s capsule,
following the enucleation of the eye .
151. The optic nerve
and its associated vessels are severed and tied close to the posterior wall of
the capsule. The implant is placed and the posterior portion of Tenon’s capsule
is closed over the implant providing the first layer of closure.
152. Next, the
anterior portion of Tenon’s capsule and conjunctiva are then closed to form the
second and third layers over the implant. The horizontal rectus muscles are
then attached to the medial and lateral fornix.
153. It is the
movement of the fomix in the enucleated socket that provides the motility to
the artificial eye. For example, as a person looks up. the inferior fomix
shortens, the superior fornix deepens and the prosthesis revolves upward
154. By utilizing the
posterior layer of Tenon’s capsule,a larger implant can be placed deep within
the muscle cone decreasing the incidence of implant migration and reducing the
tension on the anterior Tenon’s capsule sutures.
155. The larger
implant reduces the volume deficit in the superior and inferior sulcus.
preventing enophthalmos which can be produced by smaller implants. Postoperative complications may develop during
the first weeks following surgery.
156. Early extrusion
of the implant may occur secondary to orbital hematoma formation and infection,
traumatic manipulation of the tissues, or placement of too large an implant.
thus creating excess tension on Tenon’s capsule
157. The technique of
wrapping the orbital implant with fresh or preserved scleral tissue is thought
to be a deterrent for extrusion and migration of the implant and it is a
technique used quite frequently with enucleation After enucleation. a plastic conformer and
corticosieroid antibiotic ointment is placed in the socket.
158. The conformer
should fit the contour of the socket and fill the depths of the fomices. The conformer should not be removed by the
patient, and should be unnecessary, as it is designed with drainage holes to
allow mucoid discharge to escape and for insertion of postoperative medication.
159. The plastic
conformer is left in place for 4 to 6 weeks to reduce edema and maintain the
socket contours for the prosthetic eye. Following healing of the anophthalmic socket,
a stock or custom eye should be placed temporarily for cosmetic and
psychological reasons.
160. CRITERIA FOR SUCCESS OF CRANIOFACIAL OSSEOINTEGRATED
IMPLANTS According to “Swedish council on Technology assessment in Health
care”. The criteria for success is as follows. Implants are immobile as verified by clinical
examination. No prolonged symptoms, such
as pain, infection, tactile disorders or nerve damage should be present in
connection with the implants.
161. Penetrated soft
tissue should be free from irritation in at least 85% of regular out patient
postoperative checks. At least 95% of
the temporal bone implants and at least 75% of other extraoral implants should
be functional after 5 years.
162. The orbital defect The ideal defect is circumscribed fully by
bony orbital rim. The eyebrow should be intact. The soft tissue defining the
defect should be thin and immobile. The surface with in the defect may be lined
with a skin graft or even a free tissue flap.
163. An orbital
defect may be the result of a congential anomaly (facial cleft), trauma
(gunshot wound, road traffic accident) or surgery. Even with the advent of
microscovascular surgery and free tissue transfers, surgical reconstruction
alone cannot fully restore this area. Prosthetic rehabilitation is needed.
164. If the defect is
more extensive, bone and softissue grafting should be considered to restore
missing portions of the orbital rim, zygoma, or temporal or midface regions
before implant placement. The surgical restoration of contour can contribute to
a less extensive prosthesis.
165. Implant Placement Implants are commonly placed in the orbital
rim most often superiorly and laterally. Placement in the inferior rim is desirable if
the shape of the defect and access permit.
166. This improves
the stability and retention of prosthesis. In larger defects extending beyond the orbital
rim, implants can be placed in the zygoma or maxilla. Evan a single implant can help stabilize and
retain a prosthesis.
167. Surgical Positioner Actual placement of the implants is guided by
a surgical positioner. This is an
acrylic resin prototype of the prosthesis that is used intraoperatively. It indicates the ideal position for implant
placement.
168. It also serves as guide for selection of the retentive
mechanism and later as a time saving reference for the shape of the prosthesis.
169. The surgical positioner also helps determine if
preprosthetic surgery is needed before implant placement. Most often, the
lateral superior aspect of the orbital rim needs reduction to place an implant
at the location and remain with in guidelines of the positioner .
170. Implant
angulation should be parallel to the frontal plane of the face or be inward
slightly. A protrusive angulation can
interfere with positioner contour and require compromise of the ideal shape of
the prosthesis.
171. At the same time
implant should not be over- angulated inward because prosthetic access for
fabrication of retentive mechanism can be hampered. This is true especially in smaller shallow
defects when a soft-tissue flap has been used to close the opening of the
defect.
172. Abutment selection and retention systems The shortest abutment that protrudes to 1 to 2
mm above the level of skin should be selected at second-stage surgery. This can minimize stress to the implant and
still allow for hygiene and prosthetic access. A shorter abutment takes up less space in
conjunction with the retentive mechanisms.
173. At second-stage
surgery, the gauze strip surgical dressing should be wrapped carefully around
the abutments and under the healing caps so that close adaptation of skin to
the abutment and underlying bone is achieved.
174. Rubenstein
reported that orbital prostheses were fabricated with a wider variety of
attachments than any other type of bone- anchored facial prosthesis : bar
clips, magnets, ball studs or a combination of types.
175. Bar-clip systems yield the highest retentive forces. good retention for large defects, especially
when there are implants in only the superior orbital rim. When implants are splinted together by the
bar, loading can be shared among them.
176. This type of
system permits retention and support beyond the actual position of implant. At least two implants must be used for this
system, but three or more spread in a slight arch are preferred to control and
distribute forces
177. Because the
mechanism takes up more space than individual magnets, care must be taken that
the bar does not interfere with the ideal position of the ocular prosthesis.
178. REQUIREMENTS of
the bar system so as not to stress the implants.
179. Impression
making and bar construction can be difficult, especially if the implants are
excessively divergent (more than 350 ) or widely distributed around the orbital
defect. Asymmetric withdrawl of the prosthesis can result in amplification of
loads to the implants.
180. Some divergence
of implants is desirable to offer stability of the prosthesis against
horizontal forces
181. Use is limited: when the implants are divergent, and they can
introduce forces that are not along the axis of the implants. Like the bar-clip system, a prosthesis with
ball attachments can be more difficult for the patient to place than one with
magnetic attachment.
182. No retention system is ideal for all situations; each
case must be evaluated to select the optimal one
183. PROSTHETIC TECHNIQUES: I) Fabrication of the ocular
prosthesis: Ocular prosthesis is made in conjunction with the surgical
positioner because its shape and position relate to the overall shape of the
orbital prosthesis.
184. A stock eye
piece can be used. However, custom fabrication yields the best aesthetic
results. A pyramidal index of acrylic
resin is incorporated on to the back surface of the eyepiece to aid in
registering its position in the wax prototype and for subsequent mold making.
185. II) Impression making: Impression making for an orbital
prosthesis varies depending on the anatomic configuration of the orbital
defect, location of implants and type of retention system selected
186. If individual
magnets are used for retention, the MAGNACAPs are threaded into the abutments,
and the transfer magnets are placed on them. These can be connected with
autopolymerising resin to stablize them in impression.
187. The impression
can be made using irreversible hydrocolloid, a silicone rubber . The impression
should include the entire midface to provide adequate references and landmarks
for accurate sculpting
188. Orientation
lines are marked on the patient indelible pencil and will be transferred to the
cast to aid this process. After removal of the impression and disinfection,
LAB- ANALOGUE CAPS are placed against the transfer magnets and the impression
is poured in dental stone.
189. III Design and Fabrication of resin plate The resin
plate retains the retentive components in a rigid base and provides stability
for the prosthesis. In most cases, it should be as small as possible so as not
to interfere with the placement of the ocular prosthesis
190. Magnets are
placed on the lab-analogue caps on the cast. Wax is used to block out the defect and the
abutments
191. The resin
engages this area to help retain the magnets in the plate. The area is bordered
with boxing wax, and clear autopolymerising acrylic resin is poured over the
area, covering the magnets and engaging the retentive rim. The thickness should
be minimal and uniform to control distortion
192. A sprinkle on method can be used to apply the resin to
better control the thickness of the plate. Alternatively, colourless urethane
dimethacrylate visible light cure resin can be used to fabricate the plate. It
is cured initially on the cast with a handheld light and then placed in the
curing unit to complete curing.
193. The processed
plate is shaped not to interfere with the ideal contour of the prosthesis. It
is adjusted on cast and then tried on the patient. Complete engagement of
retentive elements should be verified
194. IV Sculpting the wax prototype: This is where art takes
over from science. To achieve a life like orbital prosthesis, attention to
anatomy and surface detail is important. Input from the patient and family
members is encouraged during this process.
195. To begin the
sculpting process, the ocular prosthesis is attached to resin plate with soft
utility wax while both are on the mastercast, using the orientation lines as a
guide. When the prosthesis is transferred to the patient, depth, position, and
gaze are evaluated relative to natural eye.
196. V Mold making: A three – piece mold of white improved
dental stone is made : tissue side, eyepiece and outer surface.
197. Once the wax
prototype is completed, its outline is marked on the cast with indelible pencil
. An impression of the defect extending
beyond the margins of the prosthesis is made with duplicating silicone
elastomer and resin forced with plaster backing.
198. The periphery of
this impression is poured in stone so that the center of the defect is left
open. Registration keys are placed in the tissue side of the mold.
199. Lab-analogues of
magnetic caps are placed on the magnets with in the resin plate.
200. The wax
prototype is seated back on the cast by using the transferred pencil line as
guide for orientation, and the margins are sealed. Skin surface detail can be refined at this
time
201. Stone is poured into the back of the wax prototype
through the opening of the cast .
202. Once set, wax
spacers to facilitate later mold seperation are placed in the first piece of
the mold, a seperator is applied to the stone surface, paper tape or wax is
used to box the mold, and the top portion or outer surface of the mold is
poured .
203. Once the stone
has set, the mold is separated and the eyepiece and resin plate are removed.
The mold is cleaned with boiling water and detergent to remove all wax residue
204. Before casting
the prosthesis, silicone elastomer is used to make a mold of the outer surface
of the resin plate while it is in place of on the tissue side of the mold. The impression material should be applied with
a syringe around the edges to capture the ledge on the tissue side of the
plate.
205. Then a two piece
silicone mold is of the eyepiece and this is poured in stone. This stone
reproduction is used in the mold in place of resin eyepiece during processing
to protect it from damage. These steps allow the resin plate and prosthesis to
be remade without the patient and the prosthesis present, when a replacement
prosthesis is necessary.
206. Maintenance of Prosthesis To maintain the health of the implants and
surrounding soft tissue and to preserve the prosthesis and retention mechanism.
Bone anchored facial prosthesis does
require more care on the patient’s part and closer professional follow-up than
one retained with adhesive.
207. HOME CARE AFTER ABUTMENT CONNECTION Follow up management actually begins once the
abutments have been placed. After the initial healing period and once a
surgical dressing is no longer needed, the patient should be instructed to
clean this area on a daily basis
208. The purpose is
to remove cellular material on the skin or abutment, which can come from the
interface of the epithelium and abutment. This is performed with a soft, end tuft nylon
bristle toothbrush, an interproximal dental brush or a cotton swab. To
facilitate cleaning the area should be moistened first with an even mixture of
hydrogen peroxide and water to soften any dried debris
209. When checking
abutment tightness, an abutment clamp should be placed on the abutment body to
provide countertorque so that undue force is not placed on the implant.If the
abutment loosens, complete seating should be verified before retightening. This
is done with an abutment holder.
210. HOME CARE AFTER PROSTHESIS PLACEMENT On the day that the prosthesis is given to the
patient, adequate time should be allotted for instructions on placing and
removing the prosthesis as well as proper maintenance of the prosthesis,
abutments, and surrounding skin areas. This information should be written and
given to the patient, and all steps should be demonstrated.
211. patient should
be careful when removing the prosthesis so that the thin margins do not tear
and the silicone rubber does not separate from the resin plate
212. At night, the
prosthesis should be removed and cleaned. The patients should wash their hands
first to decrease chances of soiling the prosthesis during handling. All
surfaces of the prosthesis should be cleaned gently with a soft, nylon-bristle
toothbrush and mild soap and water
213. The prosthesis
should be patted dry with a towel and placed in a covered container. A denture cup or similar type of covered
container can be used.
214. Should be stored
away from extreme heat or direct sunlight, which can cause degradation and
discolouration of the prosthetic material. The prosthesis should not be worn during sleep
so that air can circulate around the abutments to help maintain skin health
215. conclusion The goal of any prosthetic treatment is to
return the patient to society with a normal appearance and reasonable motility
of the prosthetic eye. The disfigurement resulting from loss of eye can cause
significant psychological, as well as social consequences. However with the
advancement in ophthalmic surgery and ocular prosthesis, patient can be
rehabilitated very effectively.
216. The maxillofacial
Prosthodontist should provide prosthetic treatment to the best of his ability
and should also consider psychological aspects and if necessary the help of
other specialist should be taken into consideration.
217. Sophistication
in the surgical and prosthetic reconstruction of structural and functional
defects in the craniomaxillofacial region improves the final rehabilitation
results, if carefully planned, unbiased rehabilitation regimens are established
218. Bone anchored
implant retention offers patients who wear facial prosthesis increased
security, especially with large defects or where the prosthesis rests on highly
mobile tissues. Perspiration and vigorous physical activity will not affect the
retention of bone- anchored prosthesis.
219. Independence
from reliance on adhesives for retention frees the patient from tedious task of
applying and removing adhesive at each application and removal of prosthesis.
It prolongs the life of prosthesis, because the edges are not subjected to
excessive handling.
220. The implant team must develop a co- ordinated
treatment plan that is delivered in an efficient manner. As much attention
should be paid to the fitting and care of soft tissues as to issues of hardware
articulation and registration.
221. A commitment of follow-up for the clinical evaluation
of implant tissues and the maintenance and periodic replacement of the facial
prosthesis are a team responsibility and in the best interests of the patient.
222. Textbook of
Medical Physiology – GUYTON AND HALL Review of Medical Physiology - WILLAM F.
GANONG Medical Physiology – CHAUDHARY
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