Maxillofacial implants serve a crucial role in full rehabilitation by restoring physical and psychological well-being to patients who have lost or deformed anatomical features as a result of congenital anomalies, trauma, or disease. A well-designed prosthesis, such as an artificial ear, eye, nose, cranial plate, or a combination of these, can help the patient regain appearance, functionality, and self-confidence.
Objectives of maxillofacial implants are given by,
- Enhancing the patient’s psychology
- Protecting the surgical wound
- Restoration of function
- Promoting the process of healing
- Restoring the aesthetics of the patient
The parameters that have to be considered while designing the maxillofacial implants are given by,
- The colour and texture compatibility with the patient
- The chemical and mechanical stability of the material
- Easy to fabricate
The most commonly used biomaterials are given by
- Polymers
- Acrylic resins
- Copolymers of vinyl chloride and acetate
- Silicones
- Rubbers made up of polyurethane
- Titanium, tantalum, CoCr alloys
There are two main types of maxillofacial implants, intraoral implants and extraoral implants.
Intraoral implants
Intraoral implants or dental implants are medical devices that are surgically inserted into the jaw to improve a person’s look or ability to chew. They offer support for dentures, bridges, and other artificial (fake) teeth, like crowns. When a tooth is lost as a consequence of trauma or illness, a person may encounter complications like quick bone deterioration, speech problems, or altered eating habits that are uncomfortable. The patient’s quality of life and health can be greatly enhanced by replacing a missing tooth with a dental implant. The main types of intraoral restorations that are used are given by,
- Obturators: After a maxillectomy, the obturators are a prosthesis that is used to repair palate abnormalities, restore masticatory function, and enhance speech.
- Prosthesis for congenital clefts: Congenital clefts occur when a baby’s lips or mouth don’t develop properly during pregnancy.
- Intraoral splint: A detachable dental device known as a splint covers some or all of the upper or lower teeth. Splints are normally fashioned from an impression of your teeth and made of strong acrylic resin.
- Intraoral stents
- Resection appliances: the appliances used in a mandibular resection is known as resection appliances. The surgical removal of all or a portion of the mandible is known as a mandibular resection.
Materials used for intraoral implants:
- Tantalum, titanium and CoCr alloys are used for maxilla, mandibular and facial bone.
- Silicone rubber, polymethylmethacrylate, PMMA, is used for soft tissues like gum and chitin
Ear implants
Otosclerosis and chronic otitis media-related conductive hearing loss can both be treated with implants. Silicone rubber, stainless steel, titanium, tantalum, polytetrafluoroethylene, and polyethylene are examples of materials used in such procedures. Recently, porous polyethylene, pyrolytic carbon, and polytetrafluoroethylene-carbon composites have been characterised as suitable materials for cochlear (inner ear) implants. There are two types of ear implants,
- Total implants, or TORP (Total Ossicular Replacement Prosthesis)
- Partial implants, or PORP (Partial Ossicular Replacement Prosthesis)
The reconstruction of the ossicular chain when the incus and the arch of the stapes get eroded or the malleus, incus and arch of the stapes are absent, is known as Total Ossicular Replacement Prosthesis
Cochlear implants
A cochlear implant is an electrical device that is surgically inserted into the ear. It receives sound and sends the ensuing electrical signals to electrodes inserted into the cochlea. The cochlea is stimulated by the signals, enabling the patient to hear. It also goes by the name “Bionic ear.”
Components of a cochlear implant:
- A microphone or microphones.
- Speech processor that prioritizes audible speech by carefully filtering sound.
- The transmitter, a coil kept in place by a magnet behind the external ear, uses electromagnetic induction to transport power and the signal-processed sound through the skin to the internal device.
- A receiver and stimulator anchored in the bone beneath the skin that transforms inputs into electric impulses and transmits them to electrodes through an internal connection.
- An array of up to 22 electrodes looped through the cochlea, which transmits the impulses to the auditory nerve system and the scala tympani nerves, which then travel straight to the brain.
Eye implants
To make unhealthy or damaged corneas and lenses functional again, eye implants are used. Typically, a qualified donor is used to transplant the cornea. In order to replace the natural eye lens and to regain function, intraocular lenses (IOLs) are surgically inserted. The most common complications are infection and attachment of the lens to the tissues. There are two types of eye implants,
- Non-integrated eye implants
- Integrated eye implants
Non integrated eye implants
NI do not permit the ingrowth of organic tissue into their inorganic material and do not have a special mechanism for attachment to the extraocular muscles. The extraocular rectimuscles may usually be fixed to these implants thanks to materials like donor sclera or polyester gauze, which also increases implant motility. The silicone spheres, acrylic PMMA, and glass are non-integrated implants.
Integrated eye implants
As integrated implants are porous, fibrovascular ingrowth can occur throughout them, enabling the insertion of pegs or posts. It has been attempted to create so-called “integrated implants” that are mechanically coupled directly to the artificial eye in order to increase the artificial eye’s motility. Currently, a range of materials, including natural and synthetic hydroxyapatite, aluminium oxide, and polyethylene, are used to make porous enucleation implants.
Artificial eye
An example of a craniofacial prosthesis is an artificial eye. The prosthetic is worn underneath the eyelids and over an orbital implant. Ocular prosthesis is made of medical-grade acrylic plastic and resembles a convex shell in general. Today, a small number of ocular prosthesis are built using cryolite glass.
Next – Hard tissue replacement implants
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