7. HISTORY
2500 B.C EGYPTIAN PERIOD
• First historical report of facial prosthetic replacement
was attempted during the fourth dynasty 2613/2494
B. C
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8. 200 A .D
• In china prosthesis were fabricated in lacquer
supported by a specific type of metallic
substructures .
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9. Ambroise Pare
• Has given us an excellent description of a simple
but very practical obturators for closing a
perforation in hard palate .
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11. • Pare recommended the use of prosthetic nose
made up of silver and attached to the face by
strings
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12. • He also advocated the use of a prosthesis to
replace ear and eye as well .
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13. Pierre Fauchard
• Fauchard designs for a palatal obturators
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14. • The wings are in the shape of propellers which
can be folded together while being inserted and
spread out after insertion with key .
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15. • In another type the retaining features is in the form
of a butterfly wing which is made to open by a key
after the closed wings have been inserted through
the palatal perforation .
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16. • Another of Fauchard inventions
• Is the special spring which he devised for the
retention of upper and lower denture .
JPD 1965 page 554- 568
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17. • Branemark and his associated first placed
modified osseointegrated fixtures in the cranial
bone skeletal for the purpose of retaining a
prosthetic ear in 1977.
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21. Anatomic retention
• The success of intraoral retention relates to the
size and location of the defect and outcome of
the surgery.
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22. Anatomic retention
Support
• Support is the resistance to movement of a
prosthesis toward the tissue .
• Residual maxilla and within the defect .
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23. Residual maxilla support
• Primary area available for support are
• Residual teeth
• The alveolar ridge
• Residual hard palate
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24. • The alveolar ridge support
• The size and shape of the ridge should be
consider
• Large ,broad ridge or the ridge with square or the
ovoid provide better support
(JPD 1978 vol 39 no 4 424-435)
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25. • Residual hard palate support
• Broad flat palate is more conducive to support
than the high , tapering palate
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26. With in the defect support
Floor of the orbit
Bony structures of the Pterygoid plate
Anterior surface of temporal bone
Nasal septum may used if the defect extends
beyond midline
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27. RETENTION
• Retention is the resistance to vertical displacement
of the prosthesis .
Residual maxilla retention
Alveolar ridge retention
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28. Within the defect retention
Residual soft palate
Residual hard palate
Anterior nasal apertures
Lateral scar band
Height of lateral wall
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29. • Residual soft palate retention
Palatal seal
Extension on superior surface of soft palate is
limited by the extend of the defect .
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30. • Residual hard palate
Objective of prosthesis extension is to provide
resistance to vertical and horizontal displacement
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31. • Anterior nasal apertures
Entered unilaterally or bilaterally
Depending on the extent of the defect or beyond
the midline
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32. • Lateral scar band
skin superior to the junction tends to stretch
creating an area above the scar band that can be
engaged by the obturators
Minimized vertical displacement
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33. • Height of lateral wall
In addition to the physical engagement of the floor
structures mentioned the lateral wall of the defect
can be utilized for indirect retention .
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34. STABILITY
Stability is the resistance of prosthesis displacement
by functional forces .
Rotation of prosthesis around the horizontal plane is
seen in fulcrum line .
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36. • Residual maxilla stability
If natural teeth are present prosthesis framework
can prevent the movement in all three direction
In edentulous patient , maximum extension of
prosthesis will minimized the movement.
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37. • Within the defect stability
Maximum extension of the prosthesis
Maximum contact with the medial , anterior and
lateral walls of the defect
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38. Occlusion
Unstable prosthesis results if the occlusal
relationship doesnot maintain intimate prosthesis
contact with the supporting and retentive structures.
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40. • This necessitates the use of both hard and soft
tissue .
• Retention depends on location and size of
defects
• Tissue mobility or lack of undercuts
• Weight of the facial prosthesis
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41. • Hard tissue act as a base against which to seat
the prosthesis
• Soft tissue prove to be more trouble because of
their flexibility , mobility lack of support .
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43. • Temporary mechanical retention
Stainless steel wrought wire of 18 gauge size .
some preformed wire clasps can be readily
incorporated to acrylic plate of prosthesis.
Preformed stainless steel wire clasps include
Adams , arrowhead , Akers or Hawley labial wire
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44. Permanent mechanical retention
Cast clasp other forms
Circumferential clasp
Cast wrought clasp
Combination clasp
Roach Akers clasp
Ring clasp
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45. Permanent mechanical retention
Cast clasp other forms
Attachments
Adhesives
Magnets
implants
Swing lock device
Spring
Screws
Suction cups
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46. CAST CLASP
• The clasp extends into an undercut of the
supporting tooth in order to gain retention.
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47. Circumferential clasp
• Indicated –
class III
Modification space
On the side of the arch opposite a unilateral
edentulous space
• Contraindicated-
Class I
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48. CAST WROUGHT COMBINATION
CIRCUMFERENTIAL CLASP
• In 1965 , Dr O.C. Applegate introduced a
modified wrought wire clasp assembly known as
the combination clasp .
• Indicated – class I or class II
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49. Advantages
• Has thin light contact
• Can flex in all planes
• Adjustable
• Rigid reciprocal arm can compensates for any
orthodontic force applied by the retentive arm
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51. T bar cast circumferential combination or Roach
Akers clasp
• This clasp provides a cervical approach to the
tooth surface
• Take distobuccal distolabial undercut
• Indicated
• Unilateral or bilateral distal extension
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52. Contraindicated
• When mesial undercuts are presents
• It should not be used when height of contour is
placed closer to occlusal or incisal surface.
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53. Ring or ring around clasp
• Indication
tipped molars
• The ring clasp engages undercut by encircling
almost entire tooth from its point of origin .
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54. • Disadvantages
• Difficult to adjust or repair
• Increased tooth surface coverage
• Contraindication
• If the bracing arm have to cross a soft tissue
undercut
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55. • The loss of support of a removable partial denture
by a patient who has had a maxillolectomy causes
increased pressure , torque and lever action on
the associated hard and soft tissue.
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58. Attachments can be placed into cast crowns for
the best esthetic and mechanical retention.
Most useful in rehabilitating cleft lip and cleft
palate cases .
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59. Intracoronal precision attachment
• Advantages
• Esthetic
• Less bulky
• Stable
• Less food accumulation
• Decreases stresses in abutment
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60. • Disadvantages
• Preparation of crown
• Complicated procedure
• Repair and replacement is difficult
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62. Extracoronal attachments
• Indication
• Adequate vertical space
• Disadvantages
• Damages the gingiva distal to distal abutment
tooth
• Small dead space under the male portion
• Not as precise as intracoronal attachmentwww.indiandentalacademy.com
64. STUD ATTACHEMENTS
• E.g. Dalla bona , Rotherman
• Advantages
• Easy to adjust
• Less leverage
• Disadvantages
• Cannot be use with limited space
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65. BAR ATTACHMENT
• E.g. Dolder and header
• Indication
• Bone loss around abutment
• Advantages
• Rigid splinting and
• cross arch stabilization
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68. • First given by Gillette in 1923
• Advantages
a)Adaptability to wide variety of clinical situations
b)Variations in tooth size & shape accommodated
c)Better crown contour in gingival area
Semi precision attachment/custom made
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69. DISADVANTAGES:
a) Greater lab skill
b) Repair & replacement difficult
c) Wear resistance less(made of gold alloys)
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71. • Adhesive can provide both intraoral and extra
oral defects .
• they aid in intraoral retention when surgical
defect is large
• when palate is flat
• The anterior posterior lateral septal wall with no
undercut .
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72. •Missing tuberosities
•Patient with diminished salivary flow due to pre
and post radiation therapy.
(JPD 1992 68 943-9)
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73. • Most modern prosthetic replacement are secured
with adhesives.
• All are readily available ,easily applied and can
provide satisfactory retention for limited period of
time.
(JPD 1980 vol 43 no 5)
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76. • Most commonly used adhesive .
• Strongest bond with skin .
• Care should be taken while using on compromised
skin surface .
• Can easily removed from skin .
• Difficult to remove from silicone
Dow corning 355
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77. PSAI and PROS AIDE
• Not easily removed from the skin surface
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78. Technique
Apply adhesive 6 to 7mm periphery of the surface
Repeated cleaning might lead to breakage
Not to apply at the edges of the prosthesis to
increase the life of the prosthesis
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79. Adhesive remover
• Adhesive remover are used to remove adhesive
from the skin .e.g. plastic remover , acetone
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80. • Cotton bud is socked in remover and apply slowly
under and around the fitting surface of the
prosthesis.
Technique to remove adhesive
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81. • Some patient may develop allergic and irrigational
response .
• Poor hygiene may limit the effectiveness of a
prosthesis.
• Damage external pigmentation.
( JPD 1980 vol 43 no 5 )
Disadvantages of adhesive
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82. • Difficulty in applying the adhesive or adhesive
retained prosthesis repeatedly to the proper
position.
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83. Sebum – fatty substance release from gland can
cause barrier between skin and adhesive .
Moisture – can affect the action of adhesive
Hair- prevent adhesive layer contacting skin .
Solvent – continue use of removal solvent can be
allergic to skin
Problem with adhesive
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86. History
• Magnets in maxillofacial
Prosthesis have been used for
decades to reconstruct large
defect .
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87. • Federick rehabilitated a patient with large orofacial
defect using a 2-component obturator that was
locked to each other with the help of magnets.
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88. • advances in technology have made avail-able a
new family of magnetic alloys based on cobalt and
other rare earth metals.
• They are small but strong and can be used for
dental purposes for retention.
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89. • The mutual attraction of unlike poles has been
utilized successfully to assemble multicomponent,
maxillofa-cial prostheses and even sectional
dentures
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90. • Magnets were first introduced for applications in
dentistry in the year 1953 in the field of
orthodontics.
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91. • 1960 as retentive devices for over dentures,
removable partial dentures, and maxillofacial
prostheses.
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92. • Magnets is the most efficient means of providing
combined prostheses with retention and stability in
patient with deformities requiring complex defect .
• Majority of prosthesis with magnets are sectioned
and have a magnet in each section .
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93. • When section are assemble properly
• Magnets are attracted to each other and retain the
section
( The Journal of Contemporary Dental Practice Vol 8 No 7 2007)
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97. • Ease of placement
• easy replacement
• small size with strong attractive forces
• Ease of cleaning
• Can be used with implant supported prosthesis
• They can be embedded on thin sections of
acrylic
Advantages of magnets
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98. • Tissue undercuts can be used for additional
retention of prosthesis .
( JPD 1984 VOL 52 NO 4 page 556-558)
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99. • Low corrosion resistance
• High cost
• Cytotoxic effect
Disadvantages of magnets
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100. The challenge in magnets as retentive elements
in MFP depends on ability to resist corrosion
The development of samarium iron nitride as
magnetizeable material may offer better corrosion
resistance
use of magnets in prosthodontics may be viewed
with much interest in future
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102. History
• In 1975 Branemark considered that skin penetration
implant may be possible .
• In 1977 Branemark and his coworkers Installed
specifically designed Implants
• in the mastoid region.
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103. • In 1979 these same workers placed the first
implants in the mastoid region to retain an
auricular prosthesis .
• Since these developments , craniofacial
osseointegration has become an accepted part of
head and neck reconstruction.
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104. • Implants are placed into the residual bone and then
used for retention , support and stability of a
prosthesis .
• The use of similar implants in extra oral site is
growing popularity .
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105. • Osseointegration technology offers the first real
promise for overcoming the disadvantages of
adhesive in the appropriate patient .
( JPD 1988 VOL 55 NO 5 page 600-605)
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106. Indication
Extra oral implants are used for retaining eye , ear
and nose maxillofacial prosthesis .
Patient with cartilaginous or peripheral tissue or
thick layer of skin .
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107. Contraindication
• Poor immune defense
• Use of steroids
• Neoplasm as a result of chemotherapy
• Uncontrolled endocrinopathy
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108. • Relative contraindication
• Diabetes mellitus
• Irradiated bone or ongoing radiotherapy
• Inflammation of implant site
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109. Retention system in extra oral implant
• Osseointegration implants in craniofacial
reconstruction improves prostheses retention ,
stability , comfort and safety for a patient .
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111. Bar clip attachment
Most commonly used
metallic bar clip system
present expensive laboratorial procedure
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112. • Advantages
Good load distribution on the implants.
• Disadvantages
risk of damaging the bar during construction of
prosthesis
( JPD 1996 vol 76 page 603)
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113. Magnet systems
Consists of a magnet cap that
is threaded onto the abutment
and a magnet is placed onto the
tissue surface of the prosthesis.
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114. Indicated
When abutment are not parallel
In orbital and auricular prosthesis with or without bar
clip system
Swallow defects with insufficient space for a bar and
clip attachment .
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115. • Advantages
• Ease of removing and inserting
• Makes the wearing and daily care beneficial
• Easy hygiene control
• Reduce probability of infection
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116. Ball attachment system
Three implants creating
a tripod
Provide satisfactory
retention and stability
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117. • Indication
• Shallow defects as they occupy less space
behind the prosthesis .
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118. • Advantages of ball system
• Induces less stress to implant
• Absence of bar optimizes more hygiene
• Provides freedom of movement
• Disadvantages
• Wear of the rubber ring
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120. • System provides security to patient because the
prosthesis keeps in position until the system is
unlocked .
• Disadvantages
• Silicone tear
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122. • Implant for orbital prosthesis
• Superior , lateral , and inferior rims are possible
site for implant
• 3 to 4mm implants are needed
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123. • For the large defect it is best to connect the
abutment with a bar .
( JPD 1993 70 329-332)
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128. Bar can be extended 10 to15mm
Two retention system are used gold alloy bar ,
and magnets
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129. In gold bar system 2mm gold cylinder is
attached to the abutment .
retention clip system incorporated into
prosthesis providing attachment to the bar .
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130. Excellent retention for the prosthesis .
However it may limit the access for performing
hygiene procedures , require extension of the
base of the prosthesis to cover the bar .
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131. • Second retention technique is use of magnets .
• Magnets are connected to abutment.
• 6mm diameter and 2mm thickness .
• The bar structure must be designed to contain
housings to hold magnets
• Corresponding magnets are placed within the
silicone prosthesis .
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132. • Alternative technique employed only the use of
magnets
• This technique employs a magnet keeper that
connects directly to the abutment thus elimination
the need for a retaining bar .
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134. Nasal defects
Implant can be placed in maxillary
or frontal bone
4mm implant s are required
Positioned in each lateral rounded nasal
eminence
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135. • The prosthesis is completed before the placement
of implant .
• Position of the abutments and the retentive
elements do not compromise the contours of the
prosthesis
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136. • Split thickness graft is needed .
• The septal cartilage must be reduced surgically
• Provide room for the prosthesis to engage the
lateral walls of the defect
• Increase stability of prosthesis
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138. Implant design for maxillectomy defect
• Prosthetic rehabilitation close oral & nasal
cavities, substitute teeth and anterior soft tissues
of the face.
• Anchorage - skeletal components are removed
- zygoma & pterygoid region used
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140. Implant design for midfacial defect
• Midfacial defects often result from ablative
procedures used to control malignancies of nasal
& maxillary structures.
• As the size of defect increases, complexity of
prosthetic rehabilitation increases.
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141. Jenson DT et al (1992):
• Described available sites for the implant
placement in the midfacial region
• Suggested craniofacial site classification for the
osseointegrated implants – alpha, beta & delta
sites
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147. • The titanium implant is placed during a short
surgical procedure and over time naturally
integrates with the skull bone
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148. • One stage surgical procedure ↓LA.
• Placement of Ti implant & abutment in mastoid
cortex.
• Maintenance of hair free area around the
abutment is required.
• After osseointegration, abutment is loaded with
the mechano-electric transducer system.
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149. • For hearing, the sound processor transmits
sound vibrations through the external
abutment to the titanium implant.
• The vibrating implant sets up vibrations
within the skull and inner ear that finally
stimulate the nerve fibers of the inner ear,
allowing hearing.
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151. Advantages of implants
• Aesthetic is better
• Implant simplify the cleaning procedures
• Life of prosthesis is long
• Implant retained prosthesis have provided the
opportunity to participate in routine activities .
• Provide ability to function in society with
confidence
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In maxillofacial prosthesis there exists the wide variety of types and method for gaining retention , stabilization and immobilization of the prosthesis. The problems of retention of maxillofacial prosthesis should be solved by the prosthodontists. Therefore at the time a prosthesis is designed full consideration must be given to the retention of the prosthesis .
Excavation of tombs from this period have provided evidence of the fabrication of nasal ,orbital , auricular prosthesis . Egyptologiest have reported that such prosthetic appliances were inserted after death in order to meet the religious belief that only those without physical defect would enter the kingdom of Osiris.
In one variation of this device a dried sponge was attached to the upper surface of the obturators , when the sponge become moist it expanded and held the prosthesis in place . In another variation he used a mechanical button to lock the obturators in place .
In one variation of this device a dried sponge was attached to the upper surface of the obturators , when the sponge become moist it expanded and held the prosthesis in place . In another variation he used a mechanical button to lock the obturators in place .
Both of these device were held in place by a metal band that went over the head
Anatomic undercut areas are a welcome features in the post surgical case .these may be found in the palatal area ,cheek ,retromolar ,labial ,septal posterior pharyngeal or anterior nasal spine areas
The support is available from the residual maxilla and from within the defect both must be considered
The residual alveolar ridge is important for support in both the dentulous and edentulous patient .
Although the floor has broad area for support it usually is not needed because positive support within the defect should be achieved mainly to prevent rotation of the prosthesis into the defect .the patient should use contralateral side for mastication .Pterygoid plate or temporal bone most commonly used region for support of an obturators prosthesis. Positive contact of the prosthesis with bony structures is adequate to tripod the support for an obturators so that rotation of the prosthesis into the defect is minimized. If defect that extends across the midline of the nasal septum become available for support .the nasal septum is poor support for extensive prosthesis coz it is partly cartilage and very little bearing area.
Consideration should be given both structures within the residual maxilla as well as to those within the defect that must be relied on to provide adequate prosthesis retention. Both direct and indirect retention are important .
The residual soft palate provide the palatal seal so that prevents the passage of food and liquid above the obturators .total surgical removal of the soft palate should be avoided because it creates a clinical situation similar to a congenital cleft palate in which the severity of the defect is increased because a significant protion of the maxillar also has been removed .
Anterior extension from the medial portion of the obturators prothesis provides some resistance to vertical displacement of the anterior portion of the prosthesis because this extension competes for insertion and removal with the extension over the soft palate it often must be limited .
For adequate surgical closure most large maxillary resections are lined with a split thickness skin graft along the anterior , lateral and post lateral walls of defect. A scar band result after the surgery at the level of mucobuccal fold .this graft will contract but the tissue above this graft tends to stretch crating an area above the scar band that can be engaged by the obturators
As with retention and support specific areas of the residual maxilla as well as the defect itself must be considered in minimizing the extend of these potential movement .
And provide better seal of the prosthesis with the use of an adhesive eg would be any bony wall of a defect with which part of the prosthetic device will come in contact or a cartilaginous remnant of the ear .
The most common method for retaining a prosthesis is a cast metal clasp which enters the undercuts of tooth .
Cast circumferential clasp is most commonly used clasp design in all definitive removable partial denture and also in obturators prothesis .
Generally wrought wire clasps are used for surgical and interim obturators prosthesis . However they are also used effectively in definitive obturators .
Removable partial denture designed for maxillectomy patient are further complicated by the added weight of the obturators . To help compensates for the differences of torque and levers in maxillectomy patient some dentists use retentive surfaces on the lingual aspect of the abutment teeth .
The prognosis of obturators improves with size and curvature of arch, the quality of the tissue covering the ridge and lining the defect , an abutment alignment that is curved instead of linear, the availability of teeth on the defect side for support and retention .many design require full coverage of the remaining palate for maximum support.
Chyes attachment ,chrismani ,Channel shoulder pin system
Male portion distal of abutment tooth and female part in denture base ‘
Stabilex units ,scot attachment ,
They are most commonly classified according to the manner of dispensing and described as double sided tapes, liquid , pastes, and spray adhesive
Heptane or ethyl acetate.
Patient with poor dexterity or coordination have
In 1977 branemark and his coworker installed specifically desighned implants in the mastoid region to support a bone conduction hearing aid , this pioneering work was conducted at sahlgrenska hospital in goteborg sweden.
Efficacy of implant support has been established in the restoration of edentulous and partially edentulous jaws ,
The bone in the post auricular temporal region superior lateral orbital rim , malar process or superior maxillae are excellent sites for fixture placement with appropriate access ,
It is a wire soldered to the gold cylinders and attached to the abutments by gold cylinders and attached to the abutment by gold screws .
Retentive clips are placed on the inner aspects of the prosthesis .
One of the drawbacks of bar and clip system has been that during prothesis construction the bar has to be placed into the mold so there is always the risk ,
However in selecting the magnetic systems one must consider daily activities of the patient because an accidental dislodgement of the prosthesis can occur with lateral
This system provides security to patient because the prosthesis keeps in position until the system is unlocked.
However excessive forces applied without disengagement of the system can cause silicone tear and system displacement from acrylic base.
However excessive forces applied without disengagement of the system can cause silicone ear tear and system displacement from acrylic
Because implants are not evenly distributed .the retentive bar will contain the stainless steel keepers . An acrylic resin section house the magnets possibly a clip for the prosthesis .
The temporal bone has sufficient thickness to accept a 3 to 4 mm implant , a minimum of 2 implants are needed ,positioned approximately 18mm from the center of the external auditory meatus and 15 mm from each other .the abutments are joined by a bar constructed in a c shaped design to improve the stability and retention of the prosthesis . The bar can be extended 10 to 15mm beyond the abutment for better distribution of stability and retention .
Beyond the abutments for better distribution of stability and retention .
The use of a bar and clip system can provide excellent retention for the prosthesis .
The advantage of this technique are improved access around the abutment for cleaning and easier concealment of the retention system within the normal contours of the prosthesis, early application of implants for auricle prosthesis . Lack of knowledge concerning the survivability of the shorter implants and the amount of stress applied may have attributed to an excessive number of implants being placed . Currently two implants are considered adequate for the retention of an auricle prosthesis and the supporting of eye glasses.
Abutments are connected with bar .the bar can be extended superiorly 10 to 15 mm from the abutment for better distribution of retention for the prosthesis .an acrylic resin is constructed with the prosthesis to house the retentive elements . Retentive clips or magnets can be used
A split thickness graft is needed on the sides of the defect to provide a firm no movable foundation for the nasal prosthesis . This procedure will provide room for the prosthesis will reduce the mobility of the tissue bed under the prosthesis and minimize the stress on the implants .the septal cartilage must be surgically reduced surgically anteriorly .this procedure provide
Minimum of two implant are required ,positioned in each lateral rounded nasal eminence . Because implants are not evenly distributed and are located and one part of the defect the abutments are connected with a bar. The bar can be extended superiorly 10 to 15mm from the abutments for better distribution of retention for the prosthesis . An acrylic resin section is constructed to house the retentive element .retentive clip or magnets can be used .
Tumors requiring maxillary surgical resection Para nasal sinus, palatal epithelium or from minor salivary glands in submucosa.
Alpha sites: 6 mm or more in axial bone volume available.
E.g. - anterior maxilla through the nasal fossa & the zygoma; zygomatic arch and lateral periorbital region.
Beta sites: 4-5 mm of bone available.
E.g. - superior, lateral & inferolateral orbital rims, temporal bone & zygoma.
Delta sites: marginal sites with 3 mm or less of bone available.
E.g. - locations in temporal bone, piriform rim, infraorbital rim, zygomatic buttress.
The system is surgically implanted and allows sound to be conducted through the bone rather than via the middle ear - a process known as direct bone conduction.
The Baha consists of three parts: a titanium implant, an external abutment, and a sound processor. The system works by enhancing natural bone transmission as a pathway for sound to travel to the inner ear, bypassing the external auditory canal and middle ear. Implant & cover screws are made up of pure Ti.
Flange implants - 3.75 x 3 mm
- 3.75 x 4 mm
That there defects will be less noticeable and their ability to respond to the environment enhanced .as the art and science of this technique evolve however it is anticipated that it will result in the ability to provide improved health care for patients .