|Year : 2015 | Volume
| Issue : 2 | Page : 91-96
An insight into the future beckons of maxillofacial prosthodontics: Anaplastology
Department of Prosthodontics, Bapuji Dental College and Hospital, Davanagere, Karnataka, India
|Date of Web Publication||20-Jul-2015|
Department of Prosthodontics, Bapuji Dental College and Hospital, Davanagere, Karnataka
Source of Support: None, Conflict of Interest: None
It is the god given right of every human being to appear human. Few areas of dentistry offer more challenges to the technical skills or greater satisfaction for the successful rehabilitation of function and esthetics in the patient with gross anatomic defects and deformities of the maxillofacial region. Although remarkable advances in the surgical management of oral and facial defects, but cannot be satisfactorily repaired by plastic surgery alone. Hence, the demand for maxillofacial prosthetic devices for the rehabilitation of patients with congenital or acquired defects has intensified in recent years. This paper gives an insight into the latest innovations and improvisations in the field of maxillofacial prosthodontics.
Keywords: Anaplastology, hanger burn mask, high density porous polyethylene cranial hemisphere, intra-anatomy-airway replication, silicone elastomer, three-dimensional printing, 3dMD face™ system
|How to cite this article:|
Padmaja S. An insight into the future beckons of maxillofacial prosthodontics: Anaplastology. J Dent Res Rev 2015;2:91-6
|How to cite this URL:|
Padmaja S. An insight into the future beckons of maxillofacial prosthodontics: Anaplastology. J Dent Res Rev [serial online] 2015 [cited 2020 Jul 6];2:91-6. Available from: http://www.jdrr.org/text.asp?2015/2/2/91/161213
| Introduction|| |
Face is the patient's contact with the world and it forms the physical basis for personal recognition. As the father of Indian surgery Sushrutha Samhitha said hundreds of years ago, "the love of face is next only to the love of our life and thus the mutilated cry for help." Hence in this appearance conscious society of ours, it is virtually mandatory now to have a reasonably pleasant appearance, to be accepted. Thus, people having severely disfigured or missing parts of the maxillofacial skeleton or the face in particular come for a normal appearance by artificial restorations to us. Today, with the improved knowledge, skill, materials and technique in the dentistry, it has become easy to rehabilitate oral, and facial defects with the maxillofacial prosthesis.
| Social Forces Operating to Disadvantage of Maxillofacial Patient|| |
One of the many factors which tend to operate to the disadvantage of the facially deformed is the high social value we assign to physical appeal. Television, movies, magazines, and other mass media constantly impress us with the importance of good looks for marriage, jobs and success. Hence, much emphasis is placed upon first impressions that qualities of character and mind seem negligible compared to the importance of external appearance, physical attractiveness is regarded as an important ingredient of success. With the social premium placed on physical attractiveness, unattractive facial features can effect an individual's job, personal life, and social interactions. With maxillofacial prosthesis, patient's negative attitude can be reframed into a positive attitude.
Recent advances in maxillofacial dentistry have increased demand for prosthetic rehabilitation of patients with facial defects. Increasing awareness of cancer resulting in early diagnosis and treatment employing many new surgical techniques, which are extensive and thus leave large defects that compromise function, esthetics but also the psychological status of patient. These problems require prompt rehabilitation with surgery or prosthetics. However, surgical reconstruction is often contraindicated in the presence of the large defect/high-risk patient. Prosthetics offer the advantage of quick, reversible, and medically uncomplicated rehabilitation. In addition, the restoration may be readily removed to allow evaluation of the health of underlying tissue. Prosthetic reconstruction of maxillofacial defects has become easy with the help of anaplastological team. So what is anaplastology?
Anaplastology is a branch of medicine dealing with the prosthetic rehabilitation of an absent, disfigured, developmental, and acquired defects. The term anaplastology was coined by Walter G. Spohn and is used worldwide. An individual who has the knowledge and skill in providing customized craniofacial or somato prosthesis is known as an anaplastologist. Maxillofacial prosthodontist, dental technicians, and an ocularist can be called as an anaplastologist.
It is a basic requisite for rehabilitation providing a prosthetic substitute for lost anatomy that looks normal, both topographically and optically and has borders that become part of the movements of the adjacent tissue. Considerable skill and experience is required to create such prosthesis.
| Contraindications for Plastic Surgery|| |
Traditionally, it has always been known that the role of maxillofacial prosthetist commences where the role of surgery ends in cases such as:
(1) Very large deformity (2) poor blood supply on the postradiated tissue (3) maxillofacial prosthetic repair may also be indicated for displaced facial bones in a fracture. A temporary prosthesis may be used to close the defect at various stages of plastic surgery (4) obturators can be used when surgery is contra-indicated for closure of cleft palate (5) advanced age of the patient (6) poor health.
| Maxillofacial Prosthetics as an Alternative to Plastic Surgery|| |
Maxillofacial prosthetist normally provides appliances and devices to restore esthetics and function to the patient who cannot be restored to normal appearance or function by means of plastic reconstruction. The prosthetist also may be called upon to treat individuals who are poor surgical risks for extensive plastic surgery/or those who refuse further surgery.
| Requisites of Materials Used for Maxillofacial Prosthesis|| |
Biocompatibility is the major prerequisite for a prosthetic material, but the prosthesis must also be easy and in expensive to fabricate. The finished prosthesis must be skin-like in appearance and touch. The desirable qualities include translucence, color, texture, and the tactile sensation of softness. The finished prosthesis should be resistant to chemical and physical insult, including ultraviolet light. It should be durable and strong enough to prevent tearing and should be color stable. A large number of materials have evolved in the field of anaplastology like porcelain, natural rubber, gelatin, latex, etc., in which methyl methacrylate and silicones have established themselves.  Methacrylates are relatively hard and more durable. Silicones are soft and flexible. Different elastomers have their own physical and mechanical properties and share common clinical problem such as discoloration over time (intrinsic and extrinsic discoloration due to environmental factors and loss of external pigments) and degradation of physical and mechanical properties (tear) at the margin, lack of compatibility with medical adhesives, weakening of margins by colorants, adhesives, solvents and cleansers and deterioration of static and dynamic mechanical properties. Most discoloration and tear occurs when patients remove prosthesis or adhesives.  It is reported that 12% of patients who receive ear, nose, eye, and cheek prostheses using silicone materials never wear them and there are numerous reports of dissatisfaction with the aesthetics, color stability, function or longevity of prostheses. ,,
Over the years, there has been some improvement in facial biomaterials; but still there exists a clear need for new or improved facial materials in all clinical situations. In 1976-77, the Gulf South Research Institute in New Orleans examined a variety of industrial rubber materials in response to the proposal issued by the National Institute for Dental Research in 1973. Many tests and small clinical trials were conducted on new facial prosthetic material made of low cost thermoplastic chlorinated polyethylene (CPE) at charity hospital of New Orleans (Louisiana state University). ,,,, However, studies have shown that CPE may have an advantage over conventional silicone rubber material in its ability to be repaired, relined or reconditioned, extending the life of the prosthesis. In addition, it can be used with any adhesive type. It has greater edge strength, does not support fungal growth and is cost effective as compared with silicone materials except processing of this material is complex and difficult.  A newer material like three-dimensional (3D) - Lite is an open-weave polyester material impregnated with a nontoxic resin which results in light weight and breathable material. High definition silicone gives "life-like" prosthesis with superior comfort, cosmetic restoration as close to natural as possible by providing considerable functional benefits.
| Role of Maxillofacial Prosthodontist as a Member of Anaplastology Team|| |
- Oral and maxillofacial surgeons are facing with increasing frequency situations that demand a close working relationship with maxillofacial prosthodontist. In recent years, the combined approach of surgical, orthodontic, and prosthodontics intervention has made possible the correction of many maxillomandibular deformities, previously not amenable by surgical, orthodontic or prosthodontic means alone
- The prosthodontist predetermines the most acceptable occlusal relationships attainable surgically and orthodontically; often is relied onto detail and finalize occlusal relationships to ensure a stable and long-lasting result. Consultation with speech pathologist helps prosthodontist in designing the prosthesis that fulfill the requirements of phonation 
- Maxillofacial prosthodontist can rehabilitate postsurgical defect undergoing chemotherapy/radiation therapy with radiation shielding device and radiation therapy appliances 
- With the aid of recent advancements in material science and technology, maxillofacial prosthetist will have a thorough knowledge about material property, anatomical accuracy and stability in designing orofacial prosthesis. 
| Retention of Extra Oral Facial Prosthesis|| |
Extensive surgical procedures may sacrifice a large part of anatomic retentive features which compromises retention of the maxillofacial prosthesis. Various means of retention can be categorized into:
- Anatomical anchorage - by utilizing tissue undercuts/concavities, etc
- Mechanical anchorage - by external devices such as eyeglasses, headbands or straps, stud clips, snap buttons, magnets
- Chemical anchorage - with adhesives
- Surgical anchorage - with implants which are most commonly used.
| Recent Advances in Anaplastology|| |
In 2003, Wolfaardt et al.  suggested rapid prototyping as an adjunctive tool in digitally designing maxillofacial prosthesis in head and neck construction.
In case of rhinectomy nasal defects, fabrication of nasal prosthesis should not be just for cosmetic purpose, but should be functional. The reason being, cosmetic prosthesis may not control air passage through the defect. With the use of intra anatomy airway replication design [Figure 1], the prosthesis and its sub-dermal prosthesis structure re-direct the air flow to a normal pattern thereby reducing chances of displacement of prosthesis which may occur as in coughing or sneezing that occur with cosmetic prosthesis and also it maintains voice resonance that may affect with speech articulation. Intra anatomy designs with its bone-like alloplastic removable implant act as a retentive scaffold and maintain the sub-dermal section of the prosthesis. 
In fabrication of ocular prosthesis, most traditionally followed steps are injecting impression material into the defect which may distort the site due to weight of the impression material, changes in tissue location with modification of the patient position, which cause discomfort to the patient. Recent advances in digital technique like 3dMD face™ system ,, (3dMD, Atlanta, GA) which records the impression of soft tissue digitally creating a 3D surface image [Figure 2] without contacting the impression area thereby producing 3D physical model of impression surface without any discomfort to the patient and without distorting the soft tissue as occurs in conventional impression material.
The cosmetic finger prosthesis are held in place using suction effect produced between the stump and the prosthesis or by mechanical means like rings, implants. With recent advances in implants, functional finger prosthesis can be fabricated  [Figure 3].
Implants have been widely used to retain/support intra oral/extra oral prosthesis. In case of large facial defects, fabricating implant retained facial prosthesis is multi-staged and time-consuming procedure. Till the definitive prosthesis is ready, the patient has to be with the defect. Thanks to the new protocol which uses laser scanning, computer-aided design/computer-aided manufacturing, and rapid prototyping technique, with which a provisional prosthesis can be digitally designed and fabricated [Figure 4]. This new technique provisionally restores esthetics till the patient receives a definitive prosthesis. 
|Figure 4: Reference nose with eye glasses positioned on digital model of patient|
Click here to view
After oncologic resection, the form and function of the face and body can be restored by means of reconstructive surgery. However, there are limitations to reconstructive surgery due to lack of tissue substitutes, which require the use of prosthetics to achieve the desired esthetic and functional outcome. Thus anaplastology plays an important role in reconstructive surgery in improving patient confidence and quality of life. Apart from autogenous bone, the various alloplastic materials which are most commonly used for cranioplastic reconstruction are tantalum, titanium, stainless steel (austenite), vitallium. There are a number of disadvantages associated with metal cranial implants like their high thermal conductivity which may precipitate headache and other neurological symptoms, infection, less biocompatible,  and difficult to interprete radiologically as they produce scattering in computed tomography and magnetic resonance imaging , evaluation. With the evolution of acrylic resins, silicone, and polyethylene, metals have been used less. Heat polymerized polymethyl-methacrylate are widely used in cranioplasty with no complications like infection. Only drawback with this is the radiolucency. It becomes difficult to locate it radiographically in case of fracture. A complication rate of 2 ± 12% within the first 2 years is reported in the literature with acrylic cranioplasty plate.  Eufinger and Wehmöller used customized titanium implants to restore cranial defects to achieve good esthetic results. However, the high cost and difficulty in casting are the limiting factors with the titanium implants. 
A newer implantable material, high-density porous polyethylene (HDPE)  which is available in various shapes and forms is found to be an excellent alternative to existing methods of calvarial reconstruction in being biocompatible and with good flexibility to be molded into desired contours. These HDPE hemispheres [Figure 5] are used to recontour the natural shape of the skull .
No matter how good we are, putting silicone on soft tissue during impression will deform the soft tissue, but with a digital scan, we can record the tissues more accurate 3D. In comparison with the traditional hand-sculpted, hand-cast pieces, use of 3D process along with digital principles helps an anaplastologist to create more life-like facial prosthetics that gives more accurate fit, because the prosthesis is based on a scan of the patient, not a cast. Mueller et al. used rapid prototyping to plan the facial prosthetics which makes it easy in the reconstruction of patient's features in specific shape when other techniques like mirroring techniques cannot be applied. The 3D color models  created by rapid prototyping provides contours, color shading to more "life-like" when compared to the conventional moulage impression techniques.
One of the latest innovations in the field of rapid prototyping is the Infinite Technologies Orthotics and Prosthetic 3D scanner which is used currently in fabrication of cranial helmets, smaller pediatric devices such as a prosthetic finger, foot orthotics, and small componentry used to put together the helmet.
Example: Recently a bald eagle, which was shot in the face, disfiguring upper half of her beak was rehabilitated (implanted) with a 3D printed nylon-based polymer prosthetic beak [Figure 6].
Fractures of the facial bones usually occur as a result of vehicle accidents, industrial accidents, sporting injuries, accidental fall or domestic assaults which can result in facial disfigurement or compromise in function. Most of the women are the victims of domestic violence in her lifetime. Every year, an average of 1.3 million women is the victims of physical assault caused by their intimate partner. Facial disfigurement due to acid attack, gunshot, and physical abuse make "women without a face" The American Academy of Facial and Reconstructive Surgery and American Academy of Cosmetic Dentistry sponsored two projects - "Face to Face" and "Give back a Smile." This group works in partnership with the National Coalition Against Domestic Violence to repair facial and dental injuries of victims of domestic and dating violence. 
Treating facial burn patient is a special challenge due to their close proximity to the eyes, ears, nose and nasal passages causing serious visual and pulmonary complications, impaired breathing or swallowing. Every effort should be made to prevent scarring or contracture of scar that may impact on person's self-perception and well-being. The formation of these scars can be reduced by fabricating burn mask. Historically, the conventional method used to fabricate a custom burn mask starts with impression of the affected area with alginate or plaster molding compound which is applied directly to the affected area causing pain and discomfort to the patient. Thanks to Insignia,  which employs a 3D motion tracking laser scanner and computer-aided design software to provide a custom burn mask to the patient without contacting patient's skin [Figure 7].
So what are custom burn mask/hanger burn mask? A custom splint/burn splint or mask is a clear plastic prosthesis used to apply pressure to minimize the formation of hypertrophic scars or to flatten those already present. By applying direct pressure over the wound site, it prevents the excess formation of collagen fibers and realigns them in a normal pattern, while protecting the wound site from unwanted external forces that may impair wound healing.
| Future Vision|| |
The anaplastology with its two integrated subspecialty method of management; surgical and prosthetic is at the midway position between many therapeutic options to be selected for further development to resolve the critical situations and offering better results at affordable cost and simple technique that can be used by even newly graduated practitioners. The interested researchers and developing companies are invited to investigate and fabricate new brands of materials with detailed enhanced features and properties to fulfill the requested objectives. Use of anaplastologic skills is not confined only to restorative prosthetics but forms an eye-maker for special effects head, aliens, and creature in films and television shows. Much research has to be carried out in the field of tissue engineering for the regeneration of new tissue, which may have impact in orofacial reconstruction in the future.
| Conclusion|| |
Prosthetic restoration of maxillofacial defects is an ancient art, in which success has always been limited by the unavailability of adequate materials. Although there is a tremendous improvement in the material science and technologies, there is still no ideal material that resembles or duplicates human skin.
Maxillofacial prosthetist as a part of anaplastological team can rehabilitate the maxillofacial disfigurement with more comfortable, durable, and life-like prosthesis using the latest research, advancements, materials, and techniques in our field to create confidence and sense of well-being to our patients. Advancement in technology has a profound impact on the maxillofacial restoration of form and function. And finally, prospective clinical trials to develop new treatment techniques and assess outcomes have improved treatment strategies.
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