Dental Materials for Maxillofacial Prosthetics

Maxillofacial Prosthetics

• Branch of prosthodontics concerned with restoration and/or replacement of stomatognathic and craniofacial structures with prosthesis due to acquired and congenital defects of the face.

Classification of Maxillofacial Prosthetic Materials

• Two main groups: extra oral prosthetic materials and intraoral prosthetic materials.

Extra Oral Prosthetic Materials

• Include vinyl chloride polymers, poly (methyl methacrylate), silicone, and polyurethane.
• Used for facial prosthetics.
• Silicones and polyurethane are considered most desirable for their strength.

Intraoral Prosthetic Materials

• Include silicones, poly (methyl methacrylate), Vitallium, and Titanium mesh materials.
• Silicone is valued for its tissue tolerability.
• Metallic mesh materials permit granulated tissue to migrate through the mesh.

Ideal Requirements for Maxillofacial Materials

• Biocompatibility (non-irritating, non-carcinogenic).
• Strength: strong enough to endure peripherally.
• Flexibility: flexible at temperatures from 4.4°C to 60°C.
• Chemical and environmental stability: resistant to various chemicals and environmental factors.
• Thermal conductivity: poor conductor of heat.
• Ease of processing and ease of duplication.
• Weight: light and easily retained in position, comfortable for the patient.
• Easy to sterilize.

Physical and Mechanical Properties of Maxillofacial Materials

• Tear strength: important in thin sections, such as nasal and eye prosthesis.
• Ultimate Tensile Strength and Percent (Maximum) Elongation: indicates flexibility.
• Hardness or resistance to abrasion.
• Water Sorption: affects physical properties, including color perception.
• Weight: lightweight for patient comfort and retention.

Materials for Construction of Maxillofacial Prosthesis

Acrylic Resins

• Polymethyl methacrylate was used for facial defects with little movement.
• Advantages: compatible with adhesive systems, good strength, color stability, easy to reline and repair.
• Disadvantages: rigidity, discomfort.

Polyvinylchloride and Copolymers

• Clear, tasteless, and odorless material.
• Advantages: adaptable to intrinsic and extrinsic staining.
• Disadvantages: susceptible to degradation by UV light, ozone, and peroxide, relatively rigid, and require plasticizers.

Polyurethane Elastomer

• Advantages: good stability, high tear resistance, low modulus without plasticizers, good ultimate strength and elongation, accepts intrinsic coloration.
• Disadvantages: poor color stability, poor compatibility with adhesive systems, and moisture sensitivity.

Silicones

• Most successful maxillofacial prosthetic material.
• Advantages: excellent tear and tensile strength, easier to manipulate, chemically inert, low toxicity, and high thermal and chemical stability.
• Can be stained intrinsically and/or extrinsically for a lifelike appearance.

High Temperature Vulcanized (HTV) Silicone

• Heat-vulcanized silicones for maxillofacial prostheses.
• Advantages: excellent tear strength, highest tensile strength, excellent thermal, colour and chemical stability.
• Disadvantages: poor esthetics due to opacity, less elasticity, technique sensitive.

Room Temperature Vulcanizing (RTV) Silicone

• Room-temperature-curing silicones supplied as single-component materials.
• Cure by evaporation of acetic acid.
• Prostheses are polymerized by bulk multiple packing.