maxillofacial prosthesis materials

1. Presented by:-
DR. ROHIT PATIL
MDS I
MAXILLOFACIAL
PROSTHESIS MATERIALS

2. Contents
• Introduction
• Review of literature
• Classifications
• Ideal properties
• Individual material & their advantages & disadvantages
• Comparison of physical properties
• Recent advances
• Materials for retention
• Coloring
• Disinfection of prosthesis
• Conclusion
• References

3. • Maxillofacial : Pertaining to the dental arches, the face, head, and neck
structures.
• Maxillofacial prosthetics : The branch of prosthodontics concerned with
the restoration and/or replacement of stomatognathic and
craniofacial structures with prostheses that may or may not be
removed on a regular or elective basis.
• Maxillofacial prosthesis : Any prosthesis used to replace part or all of any
stomatognathic and/or craniofacial structures.
DEFINITION (GPT 9)

4. Introduction
• Maxillofacial materials are used to correct facial defects or deformities resulting
from cancer surgery, accidents, or congenital defects.
• Maxillofacial prostheses are difficult to fabricate and have a relatively short life of
6 months to a few years in service.
• Despite availability of materials like silicone which are best suited for fabrication
of maxillofacial prostheses, the high costs especially in the Indian scenario are a
limiting factor in its usage.
• Due to economical considerations, acrylic resins which are not the best of
materials are still used more often in the fabrication of maxillofacial prostheses.

5. Review of literature
• Auricular, nasal and even ocular prostheses fabricated of various
materials like silver, gold, bronze have been found on Egyptian
mummies.
• Chinese are known to have fabricated nasal and auricular
prosthesis using natural waxes and resin.
• Alphonse Louis fabricated silver mask to French soldier who was
known as the "Gunner with the silver mask”.

6. • According to Beder; the first obturator was described in 1541 by
Ambroise Pare.It consisted of a simple disc attached to sponge.
• Tycho Brache (1546-1601), used an
artificial nose made from gold to replace
his own nose.
• William Morton (1800 to 1900) was
credited for fabrication of nasal
prosthesis using enameled porcelain
to match complexion of patient.

7. • In 18th century, Pierre Fauchard described more advanced prosthesis
which were supported by wings that could be positioned by the patient
from the oral side of the obturator and made use of the floor of the nose
for retention.
• In 1880 - Kingsley described combination of nasal palatal prosthesis in
which obturator portion was integral part of nasal prosthesis.
• Upham described the fabrication of nasal and auricular prosthesis made
from vulcanite in 19th century.
• In 1905, Ottofy and Baker used black vulcanized rubber.

8. • In 1913 – Gelatin-glycerin compounds were introduced for use in facial
prosthesis in order to mimic the softness and flexibility.
• Barnhart was the first to use silicone rubber for construction and coloring of
facial prosthesis.
• Tashma used dry earth pigments dispersed in colorless acrylic resin polymer
powder for intrinsic coloring of silicon facial prosthesis.
• In 1970 to 1990:- Gonzalez described the use of polyurethene elastomer.
• Lewis and Castel-berry described potential use of silphenylene for facial
prosthesis.

9. CLASSIFICATIONS

10. According to Beumer:
1. Acrylic resins.
2. Acrylic copolymers.
3. Polyvinyl chloride & copolymers.
4. Chlorinated polyethylene.
5. Polyurethane elastomers.
6. Silicone elastomers – HTV, RTV, Foaming silicones.
7. New materials - Silicone block copolymers, Polyphosphazenes.

11. According to Anusavice:
1. Latex- a tripolymer of Butyl acrylate, Methyl methacrylate & Methyl
methacrylamide.
2. Vinyl Plastisols.
3. Silicone Rubbers.
4. Polyurethane Polymers.

12. Extraoral
materials
acrylic resin
vinyl chloride
polymers
polyurethane
silicone
Intraoral
materials
silicones
poly (methyl
methacrylate)
J of Biomedical material research 2004:8(4);349-363

13. IDEAL PROPERTIES
Ideal Physical & Mechanical properties:
• High edge strength, elongation, tear strength.
• Softness compatible to tissue.
• Low coefficient of friction, glass transition temperature, specific
gravity, surface tension & thermal conductivity.
• Odorless, Non-inflammable, No water sorption.

14. Ideal Processing characteristics:
• Chemically inert after processing.
• Dimensionally stable during & after processing.
• Easy to repair & refabricate if needed.
• Long shelf life & working time.
• Retain intrinsic & extrinsic coloration during use.
• Short processing time.
• Low processing temperature.

15. Ideal Biological properties:
• Non-allergenic.
• Cleansable with disinfectants.
• Color stable.
• Inert to solvents and skin adhesives.
• Resistance to growth of microorganisms.
• Compatible with supporting tissues.

16. INDIVIDUAL MATERIALS

17. 1. ACRYLIC RESINS:
• In cases where little movement of tissue bed during function. (Orbital or Ocular etc).
– Acrylic powder: Polymethyl methacrylate
– Liquid : Methyl methacrylate
• The polymerization of MMA is initiated by UV light / heat as well as chemical
initiations.
• Heat polymerizing MMA is preferred over the autopolymerizing form because of the
presence of free toxic tertiary amines and color stability.
• However, since it is economical as compared to the silicones, it is still quite commonly
used.

18. Advantages:
• Durable
• Can be relined or
repaired
• Good shelf life
• Can be color matched
according to individual
skin.
• Both extrinsic & intrinsic
coloring can be
performed.
• Compatible with most
adhesive system & can
be cleaned easily.
Disadvantages:
• Rigidity
• Duplicate prosthesis is
not possible, because of
destruction of mold
during processing
• high thermal
conductivity
• Does not move as face
moves.
• Does not have the feel of
skin.
• Poor margin esthetics.

19. 2. ACRYLIC COPOLYMERS: (Palamed, Polyderm)
• Acrylic & methacrylic acid.
• Made soft by adding plasticizers.
Advantages:
• Soft
• Elastic.
Disadvantages:
• Poor edge strength
• Poor durability
• Degradation when exposed to
sun
• Processing coloration is difficult
• Completed restoration often
become tacky, predisposing to
dust collection and staining.

20. Toxicology of PMMA:
• Contact of the mucous membranes with polymer powders may cause
allergic and irritating reactions.
• Liquid monomer is a potent solvent that is highly volatile and flammable.
Due to the residual monomer release severe skin reaction may occur.
• Monomer vapors may irritate the respiratory tract leading to asthma.
• The vapors are also potentially harmful to the liver and may cause
reactions with soft contact lenses.

21. 3. VINYL PLASTISOLS & COPOLYMERS: ( Realistic, Mediplast, Prototype III)
• Introduced in 1940.
• The earliest form consisted of a combination of polyvinyl chloride (a hard,
clear resin that is tasteless and odorless) and plasticizers.
• Commonly used - vinyl chloride-vinyl acetate copolymer.
• The amount of vinyl acetate in the polymer varies from 5-20%.
• Vinyl resins that are relatively rigid in their pure state made flexible by
addition of plasticizers.

22. Polyvinyl chloride :
• Is a clear, hard resin which is tasteless and odorless.
• Darkens when exposed to ultraviolet light and heat. Therefore requires heat
and light stabilization.
Polyvinyl acetate :
• It is stable to light and heat, but has low softening temperature.
• Colouring pigments are incorporated to match the skin color.

23. Advantages:
• Flexible
• Adaptable to both intrinsic
and extrinsic coloration.
• Inexpensive & easy to
manipulate.
• Can be remade by
resoftening & reheating.
• Hydrophilic properties.
Disadvantages:
• Loss of plasticizer resulting
in discoloration.
• Edges tear easily.
• These compound can be
stained easily but degrade
when exposed to UV light.
• Absorbs sebaceous
secretions, they
compromise the physical
properties.
• Require metal molds for
curing at high temperature
which are expensive.

24. 4.Polyurethane :
• It is the most recent addition to maxillofacial prosthetics.
• Initiator used 1,4-butanediol
• It requires accurate temperature control as a
slight change in temperature can alter the
chemical reaction.
• The reaction must be carried out in a dry
atmosphere or carbon dioxide will be produced
and a porous elastomer will result.

25. Advantages
• They can be made elastic
without compromising
strength.
• They can be colored
extrinsically and intrinsically.
• Superior cosmetic results
can be obtained, surpassing
the other materials
currently available.
Disadvantages
• Difficult to process
consistently.
• Isocyanate is moisture
sensitive.
• No color stability.
• Poor compatibility of this
material with adhesive
systems.

26. 5. SILICONES:
• Introduced in 1946.
• Consists of alternate chains of silicone and oxygen which can be modified
by attaching various organic side groups to the silicon atoms or by cross
linking the molecular chains.
• They have a wide range of properties from rigid plastics through
elastomers to fluids.
• They exhibit good physical properties over a range of temperature.
• Additives are used to provide color.

27. • Most rubbery forms of silicone are compounded with fillers that provide
additional strength.
• Anti-oxidants and vulcanizing agents are used to transform the raw mass from
a plastic to a rubbery resin during processing.
• The long chained polymers, when tied together at various points (cross-
linked), create a network that can be separated only with difficulty.
• This network makes the silicones especially resistant to degradation from
ultra-violet exposure.
• The process of cross-linking the polymers is referred to as ‘Vulcanization’.
• Vulcanization occurs both with and without heat and depends on the catalytic
or cross-linking agents utilized.

28. • The tear strength of a Polydimethylsiloxane (PDMS) maxillofacial material
is extremely important particularly at the thin margins surrounding nasal
and eye prostheses.
• This thin margin helps to mask the presence of a facial prosthesis to the
surrounding facial tissue.

29. CLASSIFICATIONS :

30. HEAT VULCANIZED SILICONES (HTV) :
eg:- SILASTIC 370, 372, 373, 4-4514, 4-4515, PDM SILICONES :
• HTV silicone is a white, opaque material highly viscous, putty like consistency.
• Catalyst / vulcanizing agent  Dichlorobenzyl peroxide/ platinum salt.
• Filler  Silica (Size 30 m)
• Processing of heat cured silicones requires sophisticated instrumentation and
high temperature ( 2200C).
• Working time varies from 10-15 minutes to several hours.
• Display better strength and color stability than room-temperature vulcanizing
silicones.

31. Advantages
• Excellent thermal stability
• Color stability when exposed to
UV light.
• Superior strength
• Biologically Inert
Disadvantages
• Low edge strength
• Opaque
• Metal molds necessary for high
temperature.
• Poor wettablility
• Low elasticity

32. ROOM TEMPERATURE VULCANIZED SILICONES (RTV)
eg: (Silastic 382, 299, MDX 4-4210).
• Composed of comparatively short – chain silicone polymers which are
partially end-blocked with hydroxyl groups.
• Cross-linking agent - tetraethyoxysilane
• Filler – Silica, diatomaceous earth
• Catalyst – Chlorplatinic acid or stannous octate
• They are supplied as two-paste systems

33. • Prostheses can be polymerized in stone molds.
• Because of their good physical properties and favorable processing
characteristics RTV silicones are used more often than any other
maxillofacial prosthetic material.
• They are available as clear solution that enable the fabrication of
translucent prosthesis.
• RTV silicone is blended with suitable earth pigment; to produce the
patient basic skin color.

34. Advantages:
• Easy handling
• Quick processing
• Good thermal and color stability
• Biologically inert
• Retain physical and chemical
properties at wide range of
temperature
• Stone molds can be used.
Disadvantages:
• Poor edge strength
• Stiff
• Poor wettablility
• Costly
• Cosmetic appearance of the
material is inferior to that of
polyurethenes, acrylic resins,
polyvinyl chloride.

35. Procedure:
• Material in fluid state

• Molds – cure for 30 min

• Chloroform (cleaning)

• Uncured + xylene = Desired consistency

• Surface is tinted with artistic brushes, allowed it to stand over night

• Catalyst is gently applied with brush (Stippling other skin characteristic is done).


36. 
• Glossy surface is dulled with pumice using mild finger pressure

• Prosthesis is fitted using medical grade adhesive

• Cosmetic effect may be achieved by the patient with commercially available
make up creams.

37. Physical properties (CRAIG)
Material Tensile
strength
(psi)
Max. %
elongation
Pants tear test
(dynes/cm×106
Dynamic
modulus
(MPa)
Plasticized
polyvinylchloride
3.99 215 4.3 4.32
Polyurethane 0.83 422 6.7 3.46
HTV 5.87 441 Doesn't tear but
stretches as in tensile
4.66
RTV 4.20 445 Elongation.
2.12

38. NEWER MATERIALS

39. NEWER MATERIALS:
1. MDX4-4210 : (two component kit)
• This medical-grade silicone elastomer is basically a modified (PDMS) poly
dimethyl siloxane structure popular among clinicians.
• It exhibits improved qualities relative to coloration and edge strength.
• The polymerization reaction - no reaction by-products.
• Vulcanizing mechanism involves addition of Si-H groups to Silicone vinyl
units. JIADS VOL 1 ISSUE 2 APRIL- JUNE 2005;

40. 2. SIPHENYLENES :
• Silicone & carbon polymer.
• Three component kit –
• Base elastomer
• Tetrapropoxysilane (cross linking agent)
• Organotin (catalyst)
• Many desirable properties including bio-compatibility and resistance to
degradation on exposure to ultra violet light and heat.
• They exhibit improved edge strength and color stability over the more
conventional poly-dimethyl siloxanes.
JIADS VOL 1 ISSUE 2 APRIL- JUNE 2005;

41. 3.Silicone Block Copolymers:
• It is introduced to improve some of the weakness of silicone
elastomers, such as decreased tear strength, low percent elongation
and to support bacterial growth.
• It incorporates Polymethyl methacrylate into Siloxane blocks.
4.Polyphosphazenes:
• Fluro-elastomer has been developed for use as a resilient denture
liner, and has the potential to be used as a maxillofacial prosthetic
materials.

42. 4.COSMESIL / SILSKIN 2 SYSTEMS :
• It is a RTV silicone showing high degree of tear resistance.
• Two curing system
a) Platinum cure:
- Utilizes vinyl terminated silicone & a platinum catalyst
- Addition reaction so no by-products. Hence no shrinkage
- Working time 1 hr & curing at 1000C for 1 hr
(b) Tin cure:
- Utilizes hydroxy terminated silicone fluids & a tin catalyst
- Condensation reaction so by-product is formed
- Working time 1hr & cures in 24 hr at room temperature.

43. Advantage
• Formation of bubbles within the
mass can cause the volume to
increase by as much as 7 fold.
• Purpose of the foam silicon is to
reduce the weight of the
prosthesis.
Disadvantage
• Foamed material has reduced
strength and is susceptible to
tearing.
• This coating adds strength but at
the expense of increased stiffness.
5.FOAMING SILICONES (SILASTIC 386):
• A form of RTV silicone.
• The gas forms bubbles within the vulcanizing silicone. After the silicon is
processed, the gas is eventually released; leaving spongy material.

44. 6.LIQUID SILICONE RUBBER (LSR) SYSTEMS :
• LSR Systems are two part 100% solids, pure dimethyl silicone
elastomers, engineered for optimum performance in liquid injection
molding (LIM) processes where high clarity, high strength molded parts.
• Liquid Silicone Rubber (LSR) is a pump able, colorless, translucent paste.
• When A and B components are mixed together in equal portions by
weight, the paste will cure to a tough, optically clear elastomer via
platinum catalyzed addition-cure chemistry.
Joseph¹ S, George S, Mathew¹ C. A REVIEW OF MAXILLOFACIAL PROSTHESIS MATERIALS. EXPERT PANEL OF CONSULTANTS.

45. RECENT ADVANCES

46. • Ti, Zn, or Ce nano-oxides at concentrations of 2.0% and 2.5% improved
the overall mechanical properties of the silicone maxillofacial elastomer.
• TiO2 nanocoting effectively reduced the color degradation of the
silicone elastomer.
Effect of nanoparticles on color stability and mechanical and biological properties of maxillofacial silicone elastomer: A systematic review.
The Journal of Indian Prosthodontic Society. 2020 Jul 1;20(3):244.

47. Computer aided design and manufacturing system
• Maxillofacial prostheses are usually fabricated on the basis of
impressions made with dental impression material.
• The extent to which the prosthesis reproduces normal facial
morphology depends on the clinical judgement of the
individual fabricating the prosthesis

48. Using the CAD-CAM
Facial contours are measured using a laser.
• This method minimizes patient discomfort
and avoids soft tissue distortion by
impression material.
• Moreover, the digital data obtained is easy to
store and transmit, and mirror images can be
readily generated by computer processing.

49. Before After

50. OTHER MATERIALS
Adhesives
• Adhesives are commonly used to improve
retention and stability of a facial prosthesis to
skin.
• They provide psychological benefit to the
patient.
• Bi-phase adhesive tape is useful in materials
with poor flexibility and for patients whose
defects demonstrate little or no movement.
Double sided adhesive tape

51. • Most facial prostheses are retained with a medical
grade adhesive.
• Its selection depends on patient tolerance, ease of
application and removal, and compatibility with the
material used for the facial prosthesis.
• Most cured silicones, because of their low solubility
and low surface energy, will not adhere to
conventional tissue adhesives.
• The one - component RTV silicones were developed
to serve as adhesives for silicone prostheses.
Primers
Adhesives

52. Types of Adhesives
• Silicone-based - These are the most commonly used adhesives.
Commonly silicone particles are dispersed in ethyl acetate. e.g.
MDX 4-4210, Silastic 891( Medical Adhesive A), Dow Corning 355.
• Water-based - These are commonly used with polyurethane liners
e.g. Daro adhesive, Daro Hydrobond, Pros Aide.
• Acrylic - These adhesives can be easily mixed with water and
applied. On drying, they leave a clear layer of the material. E.g.
Beta Bond.

53. MATERIALS FOR RETENTION
Adhesive magnet plate
Neo- mini magnets
Implants
Spectacles
Sprung steel head band

54. COLORING
• Colour wise a life like maxillofacial prosthesis is defined as
the one that has distribution of pigments equivalent to
that of human skin and Whose overall colour appears to
change precisely as does that of human skin under all
types of illumination .
• Accurate representation of skin color in a facial prosthesis
is essential in achieving a successful esthetic result, yet it
remains one of the greatest challenges to the clinician.
• These include pigments (Art skin), rayon flock, thread or
yarn, and kaolin (opacifier).

55. • Achieving realistic skin color, texture, translucency, and heterogeneity requires
balance of these components.
• Effective coloration employs intrinsic and extrinsic coloring.
• Intrinsic coloration is longer lasting and is therefore preferred but is more
difficult to accomplish than extrinsic coloration.

56. Materials for Pigmentation
Basic shades are mainly metal oxides like:
– Nickel oxide - Brown
– Manganese oxide - Lavender
– Titanium oxide - Yellowish brown
– Iron oxide - Brown
– Copper oxide - Green

57. INTRINSIC COLORATION
• Intrinsic coloration is color applied within the mold during processing
procedure.
• A realistic 3-dimensional quality is accomplished by incorporating
subsurface details like blood vessels, freckles etc.
• Colours used – Enamel porcelain, Ceramics, Artist’s paint, Water soluble
dyes, Celluloid paints, Photographic stains, Acrylic resins stains, Oil
colours, etc
• Advantages - Increased service life of the prosthesis and planned
translucency.

58. Laminar glazes
• 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.
• The application of laminar glazes is an attempt to mimic the histologic
structures of human skin.
Common colors for laminar glazes are :
1. Red blush glaze – simulates classic pink appearance of skin
2. Golden tan glaze – tan color observed due to presence of
melanin.
3. Dark brown – simulates freckles and moles.
4. Dark blue or purple – applied to shadow areas

59. 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

60. Computerized Color formulation
• Spectrophotometry combined with computerized color
formulation provides an objective means of achieving a skin
match through a mix-correct-correct procedure (Troppmann et
al, 1996).
• This is accomplished with color formulation software that
matches a measured skin color.
• Advantages – decreased clinical time, metamerism is
minimized, formula can be mixed repeatedly.

61. • Facial prostheses exposed to the oral /
nasal secretions harbor micro-organisms
within the porous silicon leading to
discoloration and offensive odors.
• Microwave energy has been used to
sterilize Medical devices made of Plastic,
Silicon and Rubber.
• Even Acrylic resin Dental prostheses
have been disinfected and sterilized
with Microwave energy.
Disinfection of the Prosthesis :

62. • When reviewing the advantages and disadvantages of each of these materials, it
is obvious that no single material is ideal for every patient.
• Some of the problems inherent in all these materials are:
1. The continued effect of sunlight and vascular dilation and contraction on
the natural tissues, which cannot be duplicated in the prosthesis.
2. The variations of skin tone when the patient is exposed to different light
sources (e.g., incandescent, fluorescent, and natural light).
3. Emotional factors which cause color changes in the skin.
4. The inability of the prosthesis to duplicate the full facial movement of the
non defective side.
5. Lack of predictability of the life of the prosthesis, because of the variations
among the patients (i.e., secretions, smoking and environment).
SUMMARY :

63. Conclusion:
• As it is evident, no material has gained a favorable consensus from clinicians.
• All materials in use exhibit undesirable properties.
• Selection of a material for a facial restoration more often is dependent on the
individual experiences and preferences of the clinician.
• A keen eye and attention to detail are paramount in the ability to detect and
duplicate skin tone.
• Ultimate challenge to a material is its clinical performance.

64. • Laboratory testing should be correlated to clinical performance.
• Future research should concentrate on 2 major goals:
Improving the properties of materials, so that it will behave more like human
tissue.
Color-stable coloring agents for coloring facial prosthesis.

65. References :
1. Kenneth J Anusavice: Phillips science of dental materials, 11th edition, 755-756
2. John Beumer: Maxillofacial Rehabilitation, 323-328
3. Varoujan A. Chalian: Maxillofacial Prosthetics, 89-107
4. William R. Laney: Maxillofacial Prosthetics, 2, 6, 10,281-284, 288-291
5. D.H. Lewis &D.J. Castleberry: An Assessment Of Recent Advances In External Maxillofacial Prosthetics. JPD, 43:
426-432,1980
6. Sudarat Kiat-Amnuay et al: Color Stability of Dry Earth Pigmented Maxillofacial Silicone A-2186 Subjected to
Microwave Energy Exposure. Journal of Prosthodont Vol 14 No.2(June) 2005
7. Joseph¹ S, George S, Mathew¹ C. A REVIEW OF MAXILLOFACIAL PROSTHESIS MATERIALS. EXPERT PANEL OF
CONSULTANTS.:36.
8. J. Oral Rehab 2005,(32), 518-525
9. Restorative dental material - Craig