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MATERIALS IN 
MAXILLOFACIAL 
PROSTHODONTICS
C 
O 
N 
T 
E 
N 
T 
s
 . 
INTRODUCTION
In evolving a successful prosthetic facial 
replacement ,3 factors are necessary: 
1. Creative ability 
2. Technical knowledge, & 
3. Materials which will allow the prosthodontist 
to fully exploit these talents.
Objectives Of Maxillo-facial 
Prostheses 
Restoration of esthetics or cosmetic appearance of 
the patient 
Restoration of function 
Protection of tissues 
Therapeutic or healing effect 
Psychologic therapy 
CHALIAN,
MATERIALS
Ideal Requisites Of Maxillo-facial 
Materials…… 
1. Biocompatibility 
2. Flexibility 
3. Color and translucency 
4. Chemical and environmental stability 
5. Thermal conductivity 
BEUMER, CHALIAN
6. Ease of Processing 
7. Strength – 
8. Ease of duplication 
9. Weight 
10.Dimensional stability 
BEUMER, CHALIAN
Criteria For Maxillo-facial Materials 
Processing 
Characteristics- 
1.Low Viscosity at 
ambient temperature 
2. Intrinsic and 
extrinsic Coloration 
possible 
3.Low Solubility 
parameter 
4. Sufficient working 
time 
5. Low curing 
temperature 
Performance 
Characteristic 
(mechanical and 
physical properties) 
Tensile strength 
Tensile modulus 
Tear resistance 
Surface hardness 
JPD 1984:51;521-523
Patient accommodation 
properties- 
• Non allergic 
• Non-carcinogenic 
• Chemical and environmental 
stability 
• Moderate cost 
• Hygienic 
• Easy adherence to living 
tissue 
JPD 1984:51;521-523
Classification 
Impression 
phase Modelling 
phase 
Fabrication 
phase
Prosthetic reconstruction
The impression serve 2 purposes: 
1. Allows the dentist to accomplish the 
preliminary modeling without the patient 
present, which saves chairside time, 
eliminates unnecessary discomfort to the 
patient. 
2. Patient education and teaching aids are also 
served with the resulting model.
Room Temperature Vulcanizing 
Materials- 
Advantages 
1. Fine detail obtainable 
2. Inherent strength. 
3. Easy to obtain. 
Disadvantages 
1. Needs backing. 
2. Difficulty in adjusting setting time. 
3. Retaining walls needed for confinement of 
material. 
4. High cost. 
CHALLIAN
Modeling materials… 
Ideal Properties: 
• Malleable 
• sufficient body and strength 
• Should be possible to accept texture into this 
material which will be imparted to the 
finished mold. 
• The closer the color of the material to skin 
tone, less visual distortion 
LANEY
1. Modeling clay (sculptor’s clay) 
water based clay , when allowed to dry, becomes 
a hard stone like substance. 
Advantages 
Inexpensive 
Readily available 
Consistency can 
be adjusted 
feathered on the 
edge 
Disadvantages 
gray in color, and 
the color differential 
causes visual 
distortion 
Must be kept moist 
at all times
2. Plaster…… 
• Readily available 
• Inexpensive 
• Can be shaped or molded 
in its plastic state 
• Easily and quickly prepared 
for use 
Advantages 
• Lacks elasticity 
• Adding material to build 
contour is difficult 
• Tendency to flake on the 
surface 
• Cannot be used in 
undercuts 
Disadvantages
3. PLASTOLENE… 
prepared modeling clay with oil base 
Advantages 
Takes texture well 
Always ready for use 
Easily malleable 
Requires comparatively 
little care 
Keep a 
feather edge 
Disadvantages 
more expensive 
Color does not match skin 
tone 
seep into stone model and 
affect the finished product
4. Waxes…… 
Advantages 
keeps a feather 
edge 
Readily available 
Nominal cost 
Color similar 
to skin tone 
Disadvantages 
Model must be 
carved rather 
than sculpted 
Brittle when 
cooled 
Affect the 
finished product
Undertaker’s waxes 
Properties similar standard dental waxes, 
except for 2 characteristics: 
1. Due to low melting point, body heat allow 
it to become malleable & modeled quite 
readily with the fingers and hands 
2. The color is good in relation to skin tissue.
Fabrication phase materials 
Extraoral materials – acrylic resin 
vinyl chloride polymers 
polyurethane 
silicone 
Intraoral materials -- silicones 
poly (methyl methacrylate) 
At present silicones and polyurethane materials 
are considered most desirable - strength, even 
though both are somewhat difficult to color. 
J of Biomedical material research 2004:8(4);349-363
Extra oral materials 
1. Poly-methyl methacrylate 
- Palamed 
2. Polyvinyl polymers and copolymers 
- Realastic (poly vinyl chloride) 
- Mediplas (polyvinyl acetate chloride) 
3. Elastomers 
a) Polyurethane 
- epithane 3 
b) Silicone 
- HTV 
- RTV 
BEUMER
1. Acrylic resin 
Indications: 
 Preferred for restoring 
defects which require 
minimal movements. 
e.g. fabrication of 
orbital prostheses. 
• Useful in cases of 
rapidly changing 
defects where relining is 
mandatory. 
BEUMER
Advantages 
1. Easy to work with & to maintain. 
2. Durable. 
3. Easy to reline with a tissue conditioner or reliner. 
4. Both extrinsic & intrinsic coloring can be 
performed. 
5. Compatible with most adhesive system & can be 
cleaned easily. 
Disadvantages 
1. Rigidity 
2. Does not have the feel of skin. 
3 High thermal conductivity. 
4. Poor margin esthetics. 
5. Surface gloss present. 
BEUMER
Palamed 
 Cross linked co-polymer of methacrylics and acrylics. 
 Consists of base powders and stain concentrates, 
solvent liquid. 
 Shade guide is provided for base shade powders and 
stain concentrates. 
 Produces a soft, resilient skin with a spongy central 
mass, light weight 
 The sculptured wax is weighed to achieve the 
recommended ratio according to the weight ratio 
table. 
CHALLIAN, BEUMER
 In 1943 Tylman claimed that MMA could be 
combined with plasticizer ( PALAMED) 
 Plasticized MMA resin has been formulated 
with a foaming agent. 
 Palamed must be carefully proportioned 
because too much will result in a stiff heavy 
unstable product or too little will result in 
incomplete filled mold with large pores. 
BEUMER
Use of visible light cure resin system in 
maxillofacial prosthetics 
 VLC resins underwent polymerization without 
substantial exothermic reaction. Biologic testing 
indicated– 
 they are non toxic & biocompatible. 
 Useful in the replacement of large full-thickness 
defects in the cranium & other 
regions. 
 Also used in mandibular augmentation 
Advantages :
2. VINYL POLYMERS & 
COPOLYMERS 
 Most widely used plastics for fabrication of MFP 
 Copolymers of vinyl chloride & vinyl acetate 
 Properties are superior to those of natural rubbers 
in flexibility & resistance to sunlight & aging 
 Clinical usefulness may extend from 1-6 months 
Vinyl plastisol 
 Introduced in 1940. 
 Vinyl resins are relatively rigid in their pure state, 
made flexible by addition of plasticizers. 
 In its plastisol stage the material is a thick liquid 
formed by dispersion of small vinyl particles in 
plasticizer 
BEUMER
Advantages 
1. Inexpensive & easy to manipulate 
2. Can be remade by resoftening & reheating. 
3. Hydrophilic properties. 
Disadvantages 
1. Prosthesis made from plastisol looses its 
flexibility with aging & become hard & 
distorted. 
2. Degradation & destruction by UV light. 
3. Linotype Metal molds are used which are 
expensive. 
4. Stains easily 
BEUMER
3. Elastomers 
Elastomers have been used for over 50 years now 
to fabricate facial prostheses for individuals 
missing facial anatomy due to resection, trauma or 
even congenital anomalies. 
BEUMER
a) Polyurethane elastomer 
• ……But only 
Epithane-3 facial restorations. 
 3 component system 
Part A - polyol 
Part B- isocyanate 
Part C- initiator such as dibutyltin dilaurate or 
stannous octate) 
 Varying amount of isocyanates will change the physical 
properties of final products. 
BEUMER
ADVANTAGES 
- They can be made elastic without compromising edge 
strength. 
- Flexibility well suited to defects with movable tissue 
beds 
- Colored extrinsically & intrinsically 
- Superior cosmetic results. 
DISADVANTAGES 
- Difficult to process consistently 
- Isocyanate is moisture sensitive & toxic 
- The presence of moisture in the air, leads to 
production of CO₂ resulting in porous elastomer. 
BEUMER
 Water contamination is difficult to control 
 Requires thorough dehydration before processing if 
stone molds are used 
 Poor compatibility with existing adhesive systems 
 Difficulty in clearing adhesive from prosthesis. 
 Not color stable. 
 Clinical usefulness less than 6 months ( approx. 
3mths.) 
BEUMER
Silicone Elastomer 
• Properties of silicone 
• Disadvantages of silicone 
• Classification of silicone 
• HTV silicone 
• RTV silicone 
• Advantages of HTV over RTV
b) Silicone elastomer 
 The silicon elastomers -- introduced -1946, 
 Silicones are a combination of organic and 
inorganic compounds. 
 The first step in their production is the 
reduction of silica to elemental silicon. 
 Then by various reactions the silicon is combined 
with methyl chloride to form Dimethyl dichloro 
siloxane, which, when it reacts with water, 
forms a polymer 
BEUMER
 Polymers – translucent , watery , white fluids . 
 Fillers -- additional strength. 
 Anti-oxidants & vulcanizing agents -- transform 
the raw mass from a plastic to a rubbery resin 
during processing 
 Cross linking makes the silicones especially 
resistant to degradation from ultra-violet 
exposure. 
BEUMER
Disadvantages of silicones 
 Poor strength 
 Receive colors poorly or with difficulty 
 Some are opaque resulting in prosthesis that are 
cold and lifeless. 
 Microbial growth 
 Poor wet ability 
 Good only with silicone adhesives
Classification of silicone 
• Based on the Mechanism 
• Acc. to Application 
• Based on chemistry 
JIADS VOL 1 ISSUE 2 APRIL- JUNE 2005;
Based on the 
Mechanism 
• Room 
temperature 
(RTV) 
• High 
temperature 
(HTV) 
Acc.to 
Application 
• Implant grade 
- FDA 
requirement 
• Medical grade 
- external use 
• Clean grade 
- packaging 
• Industrial 
grade - 
industrial 
applications 
Based on 
chemistry 
• Polydimethyl 
siloxanes 
• Methyl vinyl 
/dimethyl 
siloxanes 
• Phenyl 
methylsiloxanes 
• Fluoro dimethyl 
siloxanes 
Industrial use 
JIADS VOL 1 ISSUE 2 APRIL- JUNE 2005;
HTV Silicone 
1. 1 or 2 component system with putty like 
consistency 
2. 2 primary catalysts - platinum salt (addition) 
and dichlorobenzoyl peroxide (condensation). 
3. Filler - very pure, finely divided silica (size 
30 ) 
4. Processing of heat cured silicones requires 
sophisticated instrumentation and high 
temperature. 
BEUMER
• Excellent thermal stability 
• Biologically inert 
• Color stable when exposed to 
ultraviolet light 
HTV Silicone 
Advantages 
• Opaque, lifeless 
appearance 
• Not adequate 
elasticity in 
function 
• Metal Molds 
Disadvantages
HTV silicone 
 Silastic S-6508 
 Silastic 370, 372, 373 
 Silastic 4-4514 
 Silastic 4-4515 
 MDX 4-4159 
 SE- 4524U 
 Q7- 4635 
 Q7- 4650 
 Q7- 4735 
These silicones can be preformed into various 
shapes for alloplastic implantation or facial 
prostheses. 
BEUMER. CHALLIAN;
RTV Silicone 
 Available as clear solutions 
 A viscous silicone polymer that includes a filler 
& a catalyst – 
 Stannous octoate is the most common catalyst . 
 Fillers usually diatomaceous earths - improve 
strength, but significant loss of translucency 
occurs. This problem primarily exists typically 
with Silastic 382 & 399.
2 types of RTV 
Condensation 
type 
Orthoalkyl 
silicate cross-linking 
agent 
Stannous octate 
catalyst 
Addition type 
Hydro-methyl siloxane 
cross-linking agent 
Chloroplatinic acid 
catalyst
ADVANTAGES: 
- Color stable 
- Biologically inert 
- Easier to process 
- Retain physical & chemical properties at wide range 
of temperature 
- Stone molds can be used 
DISADVANTAGES: 
- Poor edge strength 
- Costly 
- Cosmetic appearance of the material -- inferior to 
that of polyurethanes, acrylic resins, polyvinyl 
chloride.
ADVANTAGES OF 
HTV OVER RTV 
1. Less chances of air bubble entrapment, 
since hand mixing of catalyst & pigments 
with the elastomer is avoided. 
2. Increased tear strength mechanical 
durability, & chemical resistance. 
3. Increased biocompatibility and 
flexibility
FOAMING SILICONES 
 The purpose -- reduce the weight of the 
prosthesis. 
 After the silicone is processed, the gas is 
eventually released leaving a spongy material. 
 ADV--The formation of the bubbles within the 
mass can cause the volume to increase by as much 
as 7 times. 
 However, the foamed material has reduced 
strength and is susceptible to tearing. This 
weakness can be partially overcome by coating the 
foam with another silicone 
BEUMER 
Silastic 386:
Recent Advances 
MPDS- Silicone block copolymer 
Polyphosphazenes 
Silphenylenes 
MDX4-4210
MDX 4 - 4210 
 Low temperature, vulcanizing 
silicone polymer 
 Provided as a two component 
kit 
 The polymerization reaction 
is addition reaction with no 
by product 
 Very colour stable 
JIADS VOL 1 ISSUE 2 APRIL- JUNE 2005;
Advantages of this material 
 Most importantly it has a high tear strength 
compared to RTV silicones 
 Unusually thin edges can be designed in a 
prosthesis without the risk of damage during 
wear & removal. 
 Accelerated aging tests have shown that the 
elastomer is very color stable. 
JIADS VOL 1 ISSUE 2 APRIL- JUNE 2005;
SilPhenylenes 
 Arylene silicone polymer - synthesized & 
formulated as a pourable, viscous, RTV liquid 
 Transparent ,Reinforced with silica fillers. 
 Three component kit – 
 Base elastomer, 
 Tetrapropoxysilane (cross linking agent) and 
 Organotin catalyst 
JIADS VOL 1 ISSUE 2 APRIL- JUNE 2005;
Improved property 
 Unusual combination of high-tensile strength & 
low modulous (relative to other conventional RTV 
silicones) 
 Improved edge strength 
 Superior coloration 
 Feel like skin 
JIADS VOL 1 ISSUE 2 APRIL- JUNE 2005; BEUMER
MPDS -- Silicone Block Copolymers 
(Methacryloxy propyl-terminated poly dimethyl siloxane) 
 It is introduced to improve some of the 
drawbacks of silicone elastomers, such as 
decreased tear strength, low percent elongation 
& bacterial growth over prosthesis. 
 Methacrylate - (ADHEOPHILIC) reduces the 
hydrophobicity which enhances the adhesive 
bond strength to non-silicone-based adhesives
Polyphosphazenes 
 Fluoro elastomer has been developed for use as 
a resilient denture liner (NovusTM, Hygienic 
Corp.) 
 It has the potential to be used as a 
maxillofacial prosthetic material.
New organosilicone maxillofacial 
prosthetic materials 
Lai, wang, Delong, Hodges. 
 The purpose of this study is to evaluate the physical properties 
of new prosthetic materials based on methacryloxypropyl 
terminatedpolydimethylsiloxane (MPDS-MF) and to compare 
the properties with those of A-2186. 
 The hardness of MPDS-MF is similar to A-2186. However, 
tensile strength, tear strength, ultimate elongation, and 
adhesive bonding strength of MPDS-MF are higher than those 
of A-2186 
Dental Materials 18 (2002) 281 ±286
Effect of nano-oxide concentration on the mechanical 
properties of a maxillofacial silicone elastomer, 
 The purpose of this study was to evaluate the effect of different 
concentrations of nanosized oxides of various composition on the 
mechanical properties of a commercially available silicone 
elastomer. 
 Nanosized oxides (Ti, Zn, or Ce) were added in various 
concentrations to a commercial silicone elastomer (A-2186), 
 Incorporation of Ti, Zn, or Ce nano-oxides at 
concentrations of 2.0% and 2.5% improved the overall 
mechanical properties of the silicone A-2186 
maxillofacial elastomer. 
(J Prosthet Dent 2008;100:465-473)
Coloration 
 Defined as one that has a distribution of pigments 
equivalent to that of human skin and whose overall 
colour appears to change precisely as does that of a 
human skin under all types of illumination. – Chalian 
 Coloration of the prosthesis varies with the 
materials used and the preference of the clinician. 
 Basic skin tones should be developed into a shade 
guide for the materials that are used. 
 The base shade selected should be slightly lighter 
than the lightest skin tones of the patient because 
the prosthesis will darken by either extrinsic or 
intrinsic coloration. 
TAYLOR
 Coloration techniques can be divided into 3 groups: 
Extrinsic, intrinsic or combination technique. 
 The combination technique is widely used because it 
produces prosthesis with a more natural appearance. 
 The color match of the prosthesis depends largely on the 
skill of the clinician, color activity of the individual and light 
source. 
 At present the procedure is done using an empirical trial 
and error method having no standardization for future 
reference. 
TAYLOR
Intrinsic coloration: 
 Intrinsic coloration is the color applied within 
the mold during the casting procedure. 
 A three dimensional quality is accomplished by 
incorporating subsurface details such as 
blood vessels, freckles and moles. 
TAYLOR
 Knowledge of primary, secondary and 
complementary colors is helpful in selection of 
chroma. 
Primary Color Secondary Color 
Complementary 
Color 
1) Red Red+Yellow=orange Red-Green 
2) Yellow Yellow+blue=Green Yellow-Violet 
3) Blue Blue+Red=Violet Blue-Orange. 
TAYLOR
 Spectrophotometers used to measure patient skin 
color 
Kaolin Powder Calcined White 
G-102 used to create opacity with 
silicone products 
Basic Skin Pigments for 
intrinsic stain 
Dry Pigments 
Flocking / Fibres for intrinsic stains Veins
Accelerated color change in a maxillofacial 
elastomer with and without pigmentation 
 This study attempted to determine whether predictable color 
changes occur when 3 pigments are individually incorporated into 
a specific silicone elastomer. 
 The materials included an RTV elastomer; 1 natural inorganic 
pigment, burnt sienna and 2 synthetic organic pigments, Hansa 
yellow and alizarin red. 
 Acceleration was achieved… 
 If left indoors with exposure to normal levels of daylight, the 
observed color change of the specimens would likely occur but 
take more time. 
(J Prosthet Dent 2001;85:614-20.)
 Once the base color is identified, laminar glazes are 
applied to simulate the skin complex appearance. 
 Laminar glazes are layers of color painted into the 
mould before packing the base color and this is 
combined with placement of threads and flocks for 
blood vessel simulation. 
 Common colors for laminar glazes are: 
 Red bluish glaze . 
 Golden tan glaze 
 Dark brown glaze 
 Opaque Yellow White color 
 Dark blue or purple 
 Opaque, Pink to red helix color 
TAYLOR
Base color is compared to patient 
skin with red bluish glaze , layered 
over a base color 
Red bluish glaze is painted into the first layer of 
mould 
Tweezers and periodontal 
probe to place thread for blood 
vessel simulation 
Syringe used to inject 
silicone into the helical group 
Instrinsically painted 
mould prior to packing the 
base color
Extrinsic Coloration: 
 It is more predictable 
 It should be used sparingly 
 Apply the extrinsic pigments in small 
amounts and on the surface of the 
prosthesis in a stippled fashion. 
Curing can be done by placing in an 
air-circulating oven at 90°centigrade. 
 Additional glazes are applied and 
cured by using air drier. 
TAYLOR
 
Application of extrinsic color Blending the Seam 
Application of kaolin to Compressed air used to 
Cured surface of the prosthesis eliminate excess kaolin 
TAYLOR
In vitro evaluation of color change in maxillofacial elastomer 
through the use of an ultraviolet light absorber and a 
hindered amine light stabilizer. 
 This study evaluated color stability when an ultraviolet light 
absorber and hindered amine light stabilizer were mixed in the 
maxillofacial elastomer containing either organic or inorganic 
pigments. 
 The materials used were an RTV silicone elastomer, 1 natural 
inorganic dry-earth pigment (burnt sienna) and 2 synthesized 
organic pigments (hansa yellow and alizarin red), ultraviolet light 
absorber (UVA) and hindered amine light stabilizer (HALS). 
 UVA and HALS were shown to be effective in retarding color 
changes. 
J Prosthet Dent. 2004 May;91(5):483-90
Adhesives 
Introduction 
Classification 
Problem with adhesives
Introduction 
 Adhesives are expected to retain prostheses 
during ordinary & extreme facial expressions, 
build-up of sebaceous secretions & water & 
change of weather conditions. 
 Most facial prostheses are retained with a 
medical grade adhesive. 
 Selection depends -- Biocompatibility, 
-- Retentive properties 
-- Ease of applicability 
-- Removal on daily basis 
-- Nature of the material 
from which prosthesis is 
fabricated. 
BEUMER
Classification of Adhesive 
 Rubber-based liquid adhesives (natural & latex) 
 Silicone 
 Cyanoacrylates
Pressure-sensitive tape 
(double-coated polyethylene, 3M surgical tape) 
 These materials are backing strips composed of 
cloth, paper, film, foil, or laminate coated 
with a pressure-sensitive adhesive.
 The bond weaker than that of rubber adhesives. 
 Advantages - the ease of application & cleaning 
after removal. 
 Indication for biphasic tape is with materials 
that have poor flexibility & nonmobile tissue 
beds.
Silicone adhesives 
(Holister) 
 Are a form of RTV silicone dissolved in solvent. 
 Once applied, the solvent evaporates & a tacky 
surface forms that form bond with another 
surface 
 Despite their low adhesive strength, they have 
good resistance to moisture & weathering with 
low water sorption
Acrylic resin emulsions 
(Epithane-3, ProsAide) 
 Composed of acrylic resin dispersed in water 
solvent when evaporated, leaves a rubber-like 
substance. 
 Other materials -- synthetic rubber, vinyl 
acetate, reclaimed rubber, vinyl chloride, 
styrene, & methacrylic 
 Penetration & wetting -- controlled by addition 
of surfactants or altering the particle size of 
the dispersion. 
 Increasing the viscosity -- prevent penetration 
into porous surfaces.
Problems with Adhesives 
 Patients with poor manual dexterity or 
coordination may not be able to apply the 
adhesive or position the prosthesis in a 
consistent manner. 
 Margins adjacent to mobile tissue require 
constant reattachment with facial movements. 
 Allergic or irritational responses may persist. 
 Some aromatic base adhesives may curl thin 
prosthesis margins.
 Poor hygiene limit the wearing of a prosthesis , 
because of interference with adhesive qualities. 
 Routine removal of adhesive -- remove the 
external pigmentation
Limitations of the Maxillofacial 
Materials…
 No single maxillofacial material is ideal for every 
patient 
1. Continued effect of sunlight and vascular 
dilatation & contraction on the natural tissues 
cannot be duplicated in the prosthesis. 
2. Variations of skin tone when the patient is 
exposed to different light sources (e.g., 
incandescent, fluorescent, & natural light) 
cannot be duplicated in the prosthesis 
3. The prosthesis cannot duplicate the full facial 
movement of the non defective side
4. Varying physiologic conditions of the patient 
in everyday living (e.g., lack of sleep, infectious 
diseases, and edema resulting from 
interrupted lymph drainage caused by surgery) 
cannot be duplicated in the prosthesis. 
5. Inflammation caused by recent surgery, which 
subsides with time -- necessitates remaking 
the prosthesis. 
6. Lack of predictability of the life of the 
prosthesis, because of variations among 
patients (i.e., secretions, smoking, and 
environment
Conclusion…
References 
1. “Maxillofacial Prosthetics”, Chalian 
2. “Maxillofacial prosthetics” Laney WR 
3. “Clinical maxillofacial Prosthetics” Thomas D Taylor 
4. Oral and maxillofacial rehabilitation by Buemer. 
5. Robert Sanchez, comparision of physical properties of two 
types of polydimethyl siloxane, MDX4-4210 and new 
material A-2186 JPD 1992:67(5);679
6. Effect of nano-oxide concentration on the mechanical properties 
of a maxillofacial silicone elastomer, Ying Han, DDS, MS,a 
Sudarat Kiat-amnuay, DDS, MS,b John M.Powers, PhD,c and 
Yimin Zhao, DDS, PhDd, J Prosthet Dent 2008;100:465-473 
7. New organosilicone maxillofacial prosthetic materials 
Lai, wang, Delong, Hodges, Dental Materials 18 (2002) 281 ±286 
8. Accelerated color change in a maxillofacial elastomer with and 
without pigmentation, John J. Gary, Eugene F. Huget and Larry D. 
Powell, J Prosthet Dent 2001;85:614-20. 
9. In vitro evaluation of color change in maxillofacial elastomer 
through the use of an ultraviolet light absorber and a hindered 
amine light stabilizer, J Prosthet Dent,2004 May;91(5):483-90
10. An in vivo evaluation of adhesives used in 
extraoral maxillofacial prostheses. 
Haug SP, Richard GE, Margiotti E, Winkler MM, Moore 
DJ, J Prosthodont 1995 Mar;4(1):11-5. 
11. . Mechanical behavior of three maxillofacial prosthetic 
adhesive systems: A pilot project, John F. Wolfaardt, Victor 
Tam, M.Gary Faulkner, Narasimha Prasad, The journal of 
prosthetic Dentistry,vol 68;6:December 1992, Pages 943– 
949 
12. . JPD 1984:51(4):523-226.

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Maxillofacial materials

  • 1. MATERIALS IN MAXILLOFACIAL PROSTHODONTICS
  • 2. C O N T E N T s
  • 4. In evolving a successful prosthetic facial replacement ,3 factors are necessary: 1. Creative ability 2. Technical knowledge, & 3. Materials which will allow the prosthodontist to fully exploit these talents.
  • 5. Objectives Of Maxillo-facial Prostheses Restoration of esthetics or cosmetic appearance of the patient Restoration of function Protection of tissues Therapeutic or healing effect Psychologic therapy CHALIAN,
  • 7. Ideal Requisites Of Maxillo-facial Materials…… 1. Biocompatibility 2. Flexibility 3. Color and translucency 4. Chemical and environmental stability 5. Thermal conductivity BEUMER, CHALIAN
  • 8. 6. Ease of Processing 7. Strength – 8. Ease of duplication 9. Weight 10.Dimensional stability BEUMER, CHALIAN
  • 9. Criteria For Maxillo-facial Materials Processing Characteristics- 1.Low Viscosity at ambient temperature 2. Intrinsic and extrinsic Coloration possible 3.Low Solubility parameter 4. Sufficient working time 5. Low curing temperature Performance Characteristic (mechanical and physical properties) Tensile strength Tensile modulus Tear resistance Surface hardness JPD 1984:51;521-523
  • 10. Patient accommodation properties- • Non allergic • Non-carcinogenic • Chemical and environmental stability • Moderate cost • Hygienic • Easy adherence to living tissue JPD 1984:51;521-523
  • 11. Classification Impression phase Modelling phase Fabrication phase
  • 13. The impression serve 2 purposes: 1. Allows the dentist to accomplish the preliminary modeling without the patient present, which saves chairside time, eliminates unnecessary discomfort to the patient. 2. Patient education and teaching aids are also served with the resulting model.
  • 14. Room Temperature Vulcanizing Materials- Advantages 1. Fine detail obtainable 2. Inherent strength. 3. Easy to obtain. Disadvantages 1. Needs backing. 2. Difficulty in adjusting setting time. 3. Retaining walls needed for confinement of material. 4. High cost. CHALLIAN
  • 15. Modeling materials… Ideal Properties: • Malleable • sufficient body and strength • Should be possible to accept texture into this material which will be imparted to the finished mold. • The closer the color of the material to skin tone, less visual distortion LANEY
  • 16. 1. Modeling clay (sculptor’s clay) water based clay , when allowed to dry, becomes a hard stone like substance. Advantages Inexpensive Readily available Consistency can be adjusted feathered on the edge Disadvantages gray in color, and the color differential causes visual distortion Must be kept moist at all times
  • 17. 2. Plaster…… • Readily available • Inexpensive • Can be shaped or molded in its plastic state • Easily and quickly prepared for use Advantages • Lacks elasticity • Adding material to build contour is difficult • Tendency to flake on the surface • Cannot be used in undercuts Disadvantages
  • 18. 3. PLASTOLENE… prepared modeling clay with oil base Advantages Takes texture well Always ready for use Easily malleable Requires comparatively little care Keep a feather edge Disadvantages more expensive Color does not match skin tone seep into stone model and affect the finished product
  • 19. 4. Waxes…… Advantages keeps a feather edge Readily available Nominal cost Color similar to skin tone Disadvantages Model must be carved rather than sculpted Brittle when cooled Affect the finished product
  • 20. Undertaker’s waxes Properties similar standard dental waxes, except for 2 characteristics: 1. Due to low melting point, body heat allow it to become malleable & modeled quite readily with the fingers and hands 2. The color is good in relation to skin tissue.
  • 21.
  • 22. Fabrication phase materials Extraoral materials – acrylic resin vinyl chloride polymers polyurethane silicone Intraoral materials -- silicones poly (methyl methacrylate) At present silicones and polyurethane materials are considered most desirable - strength, even though both are somewhat difficult to color. J of Biomedical material research 2004:8(4);349-363
  • 23. Extra oral materials 1. Poly-methyl methacrylate - Palamed 2. Polyvinyl polymers and copolymers - Realastic (poly vinyl chloride) - Mediplas (polyvinyl acetate chloride) 3. Elastomers a) Polyurethane - epithane 3 b) Silicone - HTV - RTV BEUMER
  • 24. 1. Acrylic resin Indications:  Preferred for restoring defects which require minimal movements. e.g. fabrication of orbital prostheses. • Useful in cases of rapidly changing defects where relining is mandatory. BEUMER
  • 25. Advantages 1. Easy to work with & to maintain. 2. Durable. 3. Easy to reline with a tissue conditioner or reliner. 4. Both extrinsic & intrinsic coloring can be performed. 5. Compatible with most adhesive system & can be cleaned easily. Disadvantages 1. Rigidity 2. Does not have the feel of skin. 3 High thermal conductivity. 4. Poor margin esthetics. 5. Surface gloss present. BEUMER
  • 26. Palamed  Cross linked co-polymer of methacrylics and acrylics.  Consists of base powders and stain concentrates, solvent liquid.  Shade guide is provided for base shade powders and stain concentrates.  Produces a soft, resilient skin with a spongy central mass, light weight  The sculptured wax is weighed to achieve the recommended ratio according to the weight ratio table. CHALLIAN, BEUMER
  • 27.  In 1943 Tylman claimed that MMA could be combined with plasticizer ( PALAMED)  Plasticized MMA resin has been formulated with a foaming agent.  Palamed must be carefully proportioned because too much will result in a stiff heavy unstable product or too little will result in incomplete filled mold with large pores. BEUMER
  • 28. Use of visible light cure resin system in maxillofacial prosthetics  VLC resins underwent polymerization without substantial exothermic reaction. Biologic testing indicated–  they are non toxic & biocompatible.  Useful in the replacement of large full-thickness defects in the cranium & other regions.  Also used in mandibular augmentation Advantages :
  • 29. 2. VINYL POLYMERS & COPOLYMERS  Most widely used plastics for fabrication of MFP  Copolymers of vinyl chloride & vinyl acetate  Properties are superior to those of natural rubbers in flexibility & resistance to sunlight & aging  Clinical usefulness may extend from 1-6 months Vinyl plastisol  Introduced in 1940.  Vinyl resins are relatively rigid in their pure state, made flexible by addition of plasticizers.  In its plastisol stage the material is a thick liquid formed by dispersion of small vinyl particles in plasticizer BEUMER
  • 30. Advantages 1. Inexpensive & easy to manipulate 2. Can be remade by resoftening & reheating. 3. Hydrophilic properties. Disadvantages 1. Prosthesis made from plastisol looses its flexibility with aging & become hard & distorted. 2. Degradation & destruction by UV light. 3. Linotype Metal molds are used which are expensive. 4. Stains easily BEUMER
  • 31. 3. Elastomers Elastomers have been used for over 50 years now to fabricate facial prostheses for individuals missing facial anatomy due to resection, trauma or even congenital anomalies. BEUMER
  • 32. a) Polyurethane elastomer • ……But only Epithane-3 facial restorations.  3 component system Part A - polyol Part B- isocyanate Part C- initiator such as dibutyltin dilaurate or stannous octate)  Varying amount of isocyanates will change the physical properties of final products. BEUMER
  • 33. ADVANTAGES - They can be made elastic without compromising edge strength. - Flexibility well suited to defects with movable tissue beds - Colored extrinsically & intrinsically - Superior cosmetic results. DISADVANTAGES - Difficult to process consistently - Isocyanate is moisture sensitive & toxic - The presence of moisture in the air, leads to production of CO₂ resulting in porous elastomer. BEUMER
  • 34.  Water contamination is difficult to control  Requires thorough dehydration before processing if stone molds are used  Poor compatibility with existing adhesive systems  Difficulty in clearing adhesive from prosthesis.  Not color stable.  Clinical usefulness less than 6 months ( approx. 3mths.) BEUMER
  • 35. Silicone Elastomer • Properties of silicone • Disadvantages of silicone • Classification of silicone • HTV silicone • RTV silicone • Advantages of HTV over RTV
  • 36. b) Silicone elastomer  The silicon elastomers -- introduced -1946,  Silicones are a combination of organic and inorganic compounds.  The first step in their production is the reduction of silica to elemental silicon.  Then by various reactions the silicon is combined with methyl chloride to form Dimethyl dichloro siloxane, which, when it reacts with water, forms a polymer BEUMER
  • 37.  Polymers – translucent , watery , white fluids .  Fillers -- additional strength.  Anti-oxidants & vulcanizing agents -- transform the raw mass from a plastic to a rubbery resin during processing  Cross linking makes the silicones especially resistant to degradation from ultra-violet exposure. BEUMER
  • 38. Disadvantages of silicones  Poor strength  Receive colors poorly or with difficulty  Some are opaque resulting in prosthesis that are cold and lifeless.  Microbial growth  Poor wet ability  Good only with silicone adhesives
  • 39. Classification of silicone • Based on the Mechanism • Acc. to Application • Based on chemistry JIADS VOL 1 ISSUE 2 APRIL- JUNE 2005;
  • 40. Based on the Mechanism • Room temperature (RTV) • High temperature (HTV) Acc.to Application • Implant grade - FDA requirement • Medical grade - external use • Clean grade - packaging • Industrial grade - industrial applications Based on chemistry • Polydimethyl siloxanes • Methyl vinyl /dimethyl siloxanes • Phenyl methylsiloxanes • Fluoro dimethyl siloxanes Industrial use JIADS VOL 1 ISSUE 2 APRIL- JUNE 2005;
  • 41. HTV Silicone 1. 1 or 2 component system with putty like consistency 2. 2 primary catalysts - platinum salt (addition) and dichlorobenzoyl peroxide (condensation). 3. Filler - very pure, finely divided silica (size 30 ) 4. Processing of heat cured silicones requires sophisticated instrumentation and high temperature. BEUMER
  • 42. • Excellent thermal stability • Biologically inert • Color stable when exposed to ultraviolet light HTV Silicone Advantages • Opaque, lifeless appearance • Not adequate elasticity in function • Metal Molds Disadvantages
  • 43. HTV silicone  Silastic S-6508  Silastic 370, 372, 373  Silastic 4-4514  Silastic 4-4515  MDX 4-4159  SE- 4524U  Q7- 4635  Q7- 4650  Q7- 4735 These silicones can be preformed into various shapes for alloplastic implantation or facial prostheses. BEUMER. CHALLIAN;
  • 44. RTV Silicone  Available as clear solutions  A viscous silicone polymer that includes a filler & a catalyst –  Stannous octoate is the most common catalyst .  Fillers usually diatomaceous earths - improve strength, but significant loss of translucency occurs. This problem primarily exists typically with Silastic 382 & 399.
  • 45. 2 types of RTV Condensation type Orthoalkyl silicate cross-linking agent Stannous octate catalyst Addition type Hydro-methyl siloxane cross-linking agent Chloroplatinic acid catalyst
  • 46. ADVANTAGES: - Color stable - Biologically inert - Easier to process - Retain physical & chemical properties at wide range of temperature - Stone molds can be used DISADVANTAGES: - Poor edge strength - Costly - Cosmetic appearance of the material -- inferior to that of polyurethanes, acrylic resins, polyvinyl chloride.
  • 47. ADVANTAGES OF HTV OVER RTV 1. Less chances of air bubble entrapment, since hand mixing of catalyst & pigments with the elastomer is avoided. 2. Increased tear strength mechanical durability, & chemical resistance. 3. Increased biocompatibility and flexibility
  • 48. FOAMING SILICONES  The purpose -- reduce the weight of the prosthesis.  After the silicone is processed, the gas is eventually released leaving a spongy material.  ADV--The formation of the bubbles within the mass can cause the volume to increase by as much as 7 times.  However, the foamed material has reduced strength and is susceptible to tearing. This weakness can be partially overcome by coating the foam with another silicone BEUMER Silastic 386:
  • 49. Recent Advances MPDS- Silicone block copolymer Polyphosphazenes Silphenylenes MDX4-4210
  • 50. MDX 4 - 4210  Low temperature, vulcanizing silicone polymer  Provided as a two component kit  The polymerization reaction is addition reaction with no by product  Very colour stable JIADS VOL 1 ISSUE 2 APRIL- JUNE 2005;
  • 51. Advantages of this material  Most importantly it has a high tear strength compared to RTV silicones  Unusually thin edges can be designed in a prosthesis without the risk of damage during wear & removal.  Accelerated aging tests have shown that the elastomer is very color stable. JIADS VOL 1 ISSUE 2 APRIL- JUNE 2005;
  • 52. SilPhenylenes  Arylene silicone polymer - synthesized & formulated as a pourable, viscous, RTV liquid  Transparent ,Reinforced with silica fillers.  Three component kit –  Base elastomer,  Tetrapropoxysilane (cross linking agent) and  Organotin catalyst JIADS VOL 1 ISSUE 2 APRIL- JUNE 2005;
  • 53. Improved property  Unusual combination of high-tensile strength & low modulous (relative to other conventional RTV silicones)  Improved edge strength  Superior coloration  Feel like skin JIADS VOL 1 ISSUE 2 APRIL- JUNE 2005; BEUMER
  • 54. MPDS -- Silicone Block Copolymers (Methacryloxy propyl-terminated poly dimethyl siloxane)  It is introduced to improve some of the drawbacks of silicone elastomers, such as decreased tear strength, low percent elongation & bacterial growth over prosthesis.  Methacrylate - (ADHEOPHILIC) reduces the hydrophobicity which enhances the adhesive bond strength to non-silicone-based adhesives
  • 55. Polyphosphazenes  Fluoro elastomer has been developed for use as a resilient denture liner (NovusTM, Hygienic Corp.)  It has the potential to be used as a maxillofacial prosthetic material.
  • 56. New organosilicone maxillofacial prosthetic materials Lai, wang, Delong, Hodges.  The purpose of this study is to evaluate the physical properties of new prosthetic materials based on methacryloxypropyl terminatedpolydimethylsiloxane (MPDS-MF) and to compare the properties with those of A-2186.  The hardness of MPDS-MF is similar to A-2186. However, tensile strength, tear strength, ultimate elongation, and adhesive bonding strength of MPDS-MF are higher than those of A-2186 Dental Materials 18 (2002) 281 ±286
  • 57. Effect of nano-oxide concentration on the mechanical properties of a maxillofacial silicone elastomer,  The purpose of this study was to evaluate the effect of different concentrations of nanosized oxides of various composition on the mechanical properties of a commercially available silicone elastomer.  Nanosized oxides (Ti, Zn, or Ce) were added in various concentrations to a commercial silicone elastomer (A-2186),  Incorporation of Ti, Zn, or Ce nano-oxides at concentrations of 2.0% and 2.5% improved the overall mechanical properties of the silicone A-2186 maxillofacial elastomer. (J Prosthet Dent 2008;100:465-473)
  • 58.
  • 59. Coloration  Defined as one that has a distribution of pigments equivalent to that of human skin and whose overall colour appears to change precisely as does that of a human skin under all types of illumination. – Chalian  Coloration of the prosthesis varies with the materials used and the preference of the clinician.  Basic skin tones should be developed into a shade guide for the materials that are used.  The base shade selected should be slightly lighter than the lightest skin tones of the patient because the prosthesis will darken by either extrinsic or intrinsic coloration. TAYLOR
  • 60.  Coloration techniques can be divided into 3 groups: Extrinsic, intrinsic or combination technique.  The combination technique is widely used because it produces prosthesis with a more natural appearance.  The color match of the prosthesis depends largely on the skill of the clinician, color activity of the individual and light source.  At present the procedure is done using an empirical trial and error method having no standardization for future reference. TAYLOR
  • 61. Intrinsic coloration:  Intrinsic coloration is the color applied within the mold during the casting procedure.  A three dimensional quality is accomplished by incorporating subsurface details such as blood vessels, freckles and moles. TAYLOR
  • 62.  Knowledge of primary, secondary and complementary colors is helpful in selection of chroma. Primary Color Secondary Color Complementary Color 1) Red Red+Yellow=orange Red-Green 2) Yellow Yellow+blue=Green Yellow-Violet 3) Blue Blue+Red=Violet Blue-Orange. TAYLOR
  • 63.  Spectrophotometers used to measure patient skin color Kaolin Powder Calcined White G-102 used to create opacity with silicone products Basic Skin Pigments for intrinsic stain Dry Pigments Flocking / Fibres for intrinsic stains Veins
  • 64. Accelerated color change in a maxillofacial elastomer with and without pigmentation  This study attempted to determine whether predictable color changes occur when 3 pigments are individually incorporated into a specific silicone elastomer.  The materials included an RTV elastomer; 1 natural inorganic pigment, burnt sienna and 2 synthetic organic pigments, Hansa yellow and alizarin red.  Acceleration was achieved…  If left indoors with exposure to normal levels of daylight, the observed color change of the specimens would likely occur but take more time. (J Prosthet Dent 2001;85:614-20.)
  • 65.  Once the base color is identified, laminar glazes are applied to simulate the skin complex appearance.  Laminar glazes are layers of color painted into the mould before packing the base color and this is combined with placement of threads and flocks for blood vessel simulation.  Common colors for laminar glazes are:  Red bluish glaze .  Golden tan glaze  Dark brown glaze  Opaque Yellow White color  Dark blue or purple  Opaque, Pink to red helix color TAYLOR
  • 66. Base color is compared to patient skin with red bluish glaze , layered over a base color Red bluish glaze is painted into the first layer of mould Tweezers and periodontal probe to place thread for blood vessel simulation Syringe used to inject silicone into the helical group Instrinsically painted mould prior to packing the base color
  • 67.
  • 68. Extrinsic Coloration:  It is more predictable  It should be used sparingly  Apply the extrinsic pigments in small amounts and on the surface of the prosthesis in a stippled fashion. Curing can be done by placing in an air-circulating oven at 90°centigrade.  Additional glazes are applied and cured by using air drier. TAYLOR
  • 69.  Application of extrinsic color Blending the Seam Application of kaolin to Compressed air used to Cured surface of the prosthesis eliminate excess kaolin TAYLOR
  • 70. In vitro evaluation of color change in maxillofacial elastomer through the use of an ultraviolet light absorber and a hindered amine light stabilizer.  This study evaluated color stability when an ultraviolet light absorber and hindered amine light stabilizer were mixed in the maxillofacial elastomer containing either organic or inorganic pigments.  The materials used were an RTV silicone elastomer, 1 natural inorganic dry-earth pigment (burnt sienna) and 2 synthesized organic pigments (hansa yellow and alizarin red), ultraviolet light absorber (UVA) and hindered amine light stabilizer (HALS).  UVA and HALS were shown to be effective in retarding color changes. J Prosthet Dent. 2004 May;91(5):483-90
  • 71. Adhesives Introduction Classification Problem with adhesives
  • 72. Introduction  Adhesives are expected to retain prostheses during ordinary & extreme facial expressions, build-up of sebaceous secretions & water & change of weather conditions.  Most facial prostheses are retained with a medical grade adhesive.  Selection depends -- Biocompatibility, -- Retentive properties -- Ease of applicability -- Removal on daily basis -- Nature of the material from which prosthesis is fabricated. BEUMER
  • 73. Classification of Adhesive  Rubber-based liquid adhesives (natural & latex)  Silicone  Cyanoacrylates
  • 74. Pressure-sensitive tape (double-coated polyethylene, 3M surgical tape)  These materials are backing strips composed of cloth, paper, film, foil, or laminate coated with a pressure-sensitive adhesive.
  • 75.  The bond weaker than that of rubber adhesives.  Advantages - the ease of application & cleaning after removal.  Indication for biphasic tape is with materials that have poor flexibility & nonmobile tissue beds.
  • 76. Silicone adhesives (Holister)  Are a form of RTV silicone dissolved in solvent.  Once applied, the solvent evaporates & a tacky surface forms that form bond with another surface  Despite their low adhesive strength, they have good resistance to moisture & weathering with low water sorption
  • 77. Acrylic resin emulsions (Epithane-3, ProsAide)  Composed of acrylic resin dispersed in water solvent when evaporated, leaves a rubber-like substance.  Other materials -- synthetic rubber, vinyl acetate, reclaimed rubber, vinyl chloride, styrene, & methacrylic  Penetration & wetting -- controlled by addition of surfactants or altering the particle size of the dispersion.  Increasing the viscosity -- prevent penetration into porous surfaces.
  • 78. Problems with Adhesives  Patients with poor manual dexterity or coordination may not be able to apply the adhesive or position the prosthesis in a consistent manner.  Margins adjacent to mobile tissue require constant reattachment with facial movements.  Allergic or irritational responses may persist.  Some aromatic base adhesives may curl thin prosthesis margins.
  • 79.  Poor hygiene limit the wearing of a prosthesis , because of interference with adhesive qualities.  Routine removal of adhesive -- remove the external pigmentation
  • 80. Limitations of the Maxillofacial Materials…
  • 81.  No single maxillofacial material is ideal for every patient 1. Continued effect of sunlight and vascular dilatation & contraction on the natural tissues cannot be duplicated in the prosthesis. 2. Variations of skin tone when the patient is exposed to different light sources (e.g., incandescent, fluorescent, & natural light) cannot be duplicated in the prosthesis 3. The prosthesis cannot duplicate the full facial movement of the non defective side
  • 82. 4. Varying physiologic conditions of the patient in everyday living (e.g., lack of sleep, infectious diseases, and edema resulting from interrupted lymph drainage caused by surgery) cannot be duplicated in the prosthesis. 5. Inflammation caused by recent surgery, which subsides with time -- necessitates remaking the prosthesis. 6. Lack of predictability of the life of the prosthesis, because of variations among patients (i.e., secretions, smoking, and environment
  • 84. References 1. “Maxillofacial Prosthetics”, Chalian 2. “Maxillofacial prosthetics” Laney WR 3. “Clinical maxillofacial Prosthetics” Thomas D Taylor 4. Oral and maxillofacial rehabilitation by Buemer. 5. Robert Sanchez, comparision of physical properties of two types of polydimethyl siloxane, MDX4-4210 and new material A-2186 JPD 1992:67(5);679
  • 85. 6. Effect of nano-oxide concentration on the mechanical properties of a maxillofacial silicone elastomer, Ying Han, DDS, MS,a Sudarat Kiat-amnuay, DDS, MS,b John M.Powers, PhD,c and Yimin Zhao, DDS, PhDd, J Prosthet Dent 2008;100:465-473 7. New organosilicone maxillofacial prosthetic materials Lai, wang, Delong, Hodges, Dental Materials 18 (2002) 281 ±286 8. Accelerated color change in a maxillofacial elastomer with and without pigmentation, John J. Gary, Eugene F. Huget and Larry D. Powell, J Prosthet Dent 2001;85:614-20. 9. In vitro evaluation of color change in maxillofacial elastomer through the use of an ultraviolet light absorber and a hindered amine light stabilizer, J Prosthet Dent,2004 May;91(5):483-90
  • 86. 10. An in vivo evaluation of adhesives used in extraoral maxillofacial prostheses. Haug SP, Richard GE, Margiotti E, Winkler MM, Moore DJ, J Prosthodont 1995 Mar;4(1):11-5. 11. . Mechanical behavior of three maxillofacial prosthetic adhesive systems: A pilot project, John F. Wolfaardt, Victor Tam, M.Gary Faulkner, Narasimha Prasad, The journal of prosthetic Dentistry,vol 68;6:December 1992, Pages 943– 949 12. . JPD 1984:51(4):523-226.

Editor's Notes

  1. As human face constitutes a centre of attention in human relationships, the emotional pressure because of facial disfigurement can produce high degree of handicap. The rehabilitation needed is more because of patient’s psychological & emotional demands rather than their physical deficits
  2. Materials design & properties are the main problems faced by scientists in this field. Materials used for maxillofacial prostheses are not ideal, but they have been perfected to the point of practical use
  3. In either of the situtatuion a prosthesis that has greates cmfort and security has to be fabriacted for the patient
  4. compatible with human skin & with skin adhesives. non-carcinogenic. should not cause any irritation to the tissues and any inflammatory reaction. blend with the adjacent skin as close as possible, be resistant to abrasion, outdoor weathering, body oils .It should be resistant to microorganisms commonly found in the orofacial environment.
  5. prosthetic material should be easy to manipulate, mold and process. processing should not employ complicated techniques and machinery.
  6. Ten str- max strength the srtucture will withstand witout fracture. Ela mod-relative stiffness or rigidity of the material within the elastic range.
  7. to facilitate making gross adjustments to the contours. o permit sculpting a feather edge and yet be able to withstand slight abuse.
  8. Specific types of facial defects, particularly those in which little movement occurs in the tissue bed during function
  9. Base- 20 pale, 21 med, 24 dark Stain- 30 brown, 40 red, 50 violet, 60 gray Every I gm of wax- liquid powder ratio is suggested.
  10. Due to heat or initiating chemical, a foaming agent releases gas i.e. incorporated in the material as it cures. The resulting product is spongy, with a solid skin wherever the material contacts the mold surface
  11. Accuracy of fit Ease of fabrication Ease of manipulation
  12. Polyurethane elastomer serve a variety of commercial uses, but only epithane-3 available for facial restoration .termed as polyurethanes coz they contain urethane linkages.
  13. most widely used materials for facial restorations today Objectionable properties like poor tear & tensile strength….n receives color with difficulty
  14. Based on the Mechanism Acc. to Application
  15. Implant grade- material undergo extensive testing and must meet FDA requirements. Medical grade - approved for external use. This material is used for the fabrication of maxillofacial prosthesis. Polydimethylsiloxanes & methyl vinyl /dimethyl siloxanes – medical grade
  16. Varying amounts of filler are added to these polymers depending on the degree of hardness, strength and elongation desired.
  17. that enable the fabrication of translucent prostheses. acts as a cross-linking agent, makes up a two component system of silicones
  18. ( HTV-65psi, RTV- 29) ( Sialistic S-6508 -490% , Sialistic 399- 230% , Sialistic 382 – 100% )
  19. This weakness can be partially overcome by coating the foam with another silicone This coating adds strength but at the expense of increased stiffness. Because of these problems the foaming silicones have been used by only few clinicians for facial prostheses
  20. This material is not heavily filled & has a different catalyst (chloroplatinic acid ) & hydro-methyl siloxane as a cross-linking agent.
  21. Silicone block co polymers are new materials under development to improve some of the weakness of silicone elastomers. It has been found that silicone block co polymers are more tear resistance than conventional cross linked silicone polymers.methacrilate loacated at side chain undergo free radical thermal polymerisation and crosslinking and responsible for improved mech and bonding charsacteristics. The presence of methacrylate groups in MPDS-MF enhances its adhesion to non-silicone based adhesive. - ! %
  22. Significance: MPDS-MF is cured by free radical thermal polymerization and crosslinking. The working time of MPDS-MF, unlike A- 2186, is long. The presence of methacrylate groups in MPDS-MF enhances its adhesion to non-silicone based adhesive. Based on the present study, it appears that MPDS-MF is suitable for use in fabricating of clinical prostheses.
  23. Incorporation of Ti, Zn, or Ce nano-oxides at concentrations of 2.0% and 2.5% improved the overall mechanical properties of the silicone A-2186 maxillofacial elastomer.
  24. Depth of color and translucency can be more accurately achieved through intrinsic techniques. Advantages: Increases service life of the prosthesis. Less vulnerable to environmental conditions and handling. A basic understanding of color theory (Hue, Chroma, Value) will help the clinician to select the color of patient's skin tone
  25. Proper lightening is essential for an effective color match in facial prosthesis. However a color match is best evaluated under various light sources such as daylight, fluorescent and incandescent light to reduce metamerism. 
  26. The colorants used in the coloring of a facial prosthesis are: Enamel porcelain Ceramics Artist's paint Water soluble dyes Celluloid paints Photographic stains Acrylic resins stains Oil colors and paints Dry earth pigment Nylon flocking Commercial cosmetics Ceramic pigments
  27. …by outdoor actinic radiation in concert with other factors, such as air temperature, relative humidity, dampness caused by meteorologic precipitation, and possible air pollutants.
  28. Intrinsic laminar painting is best achieved using fast set silicone. If colors migrate during processing, corrections can be made with extrinsic coloration. The base color is the last color placed in the mold. While packing, take care not to disturb the laminar color. Syringe is used to inject the silicone into the mold. Close the flask, place the mold in clamps and process according to manufacture's instructions. After processing, prosthesis is carefully retrieved and trimmed. Evaluate the value of the prosthesis. It can be corrected by extrinsic coloration.
  29. Extrinsic coloration is the color applied to the surface of a prosthesis that has been cured and removed from the mold. Isopropyl alcohol or methanol is used to clean the surface of the prosthesis prior to extrinsic coloration of silicone. due to its vulnerability to environmental conditions and handling.
  30. The application of extrinsic glazes often results in a glossy appearance which may appear unnatural. Several techniques exist to eliminate the shiny surface. Cosmetic foam applicators. Alteration of surface geometry by incorporating silica fibers into silicone elastomer. Application of Kaolin powder to the cured surface of prosthesis.
  31. Specimens (n=160) were fabricated in a custom mold and randomly assigned and exposed to weathering sites in Miami and Phoenix for approximately 3 months. In specimen groups with the additives (UVA and HALS), color change decreased significantly (P<.05) in burnt sienna and hansa yellow in Phoenix and in the control and hansa yellow in Miami. Additives did not affect color change in the alizarin red group. Ultraviolet light absorber (UVA) and hindered amine light stabilizer (HALS) retard sun-induced pigment degradation in silicone elastomeric maxillofacial prostheses. HALS inhibits polymer degradation and UVA dissipates UV radiation. Their effects on oral cells are unknown.
  32. Other materials within mixture – synthetic rubber…..
  33. All materials in use exhibit undesirable properties Selection of a material for a facial restoration -- dependant on the individual experiences & preferences of the clinician Planning the prosthesis, making the impression, sculpting the model, & choosing the material – all contribute to a successful prosthesis