Maxillofacial materials

Maxillofacial materials are used in dentistry for prosthodontic reconstruction, for example with patients who have experienced accidents or cancer surgery that involved the orofacial complex. Currently, silicone and polyurethane elastomers are employed for these applications [1,2]. 

Essential requirements for maxillofacial materials are biocompatibility, the capability of shade matching to the surrounding soft tissues, and adequate mechanical properties to provide acceptable clinical longevity. It is desirable that the viscoelastic response and creep compliance of these materials mimic the in vivo force response of these soft tissues under ftmctional loading without undergoing excessive dimensional changes over time. 

Since the viscoelastic and creep properties of polymeric materials are often correlated with their glass-transition temperatures (Tg) [40], we considered that DSC would be a useful technique to investigate commercial maxillofacial materials. In our pioneering study [41], the effects of pigments on the DSC plots were studied for a heat-polymerized maxillofacial silicone (MDX 4-4515, Dow Coming, Midland, MI, USA), which served as a model material. 

Figure 13. Heating DSC plot for lightest shade of MDX 4-4515 silicone maxillofacial material [41]. Reproduced with permission from Quintessence Publishing Company, Inc.

The preceding research on the model maxillofacial material was followed by TMDSC study of several representative elastomeric impression materials, which are extensively used in dentistry for the accurate fabrication of inlays and crowns from dental alloys, metal-ceramic restorations, and fixed and removable partial dentures [1-3]. There have been numerous studies reporting the clinically relevant properties of these impression materials (viscosity before setting by polymerization, strain in compression after setting, permanent deformation for simulated in vivo removal of the impressions, and tear strength of the thin impressions). However, only minimal research has been reported [44] on some thermal properties of impression materials obtained by conventional DSC. Our pioneering TMDSC study [45] was designed to obtain fundamental information about impression materials and seek correlations with their relevant properties. 

Dootz, E. R.. Koran, A. Craig, R. G. (1994) Physical properties of 3 maxillofacial materials as a function of accelerated aging. Journal of Prosthetic Dentistry, 71, 379-383. 

The various dental polymers discussed in this article include impression materials, dentures and denture liners, artificial teeth, crown and bridge materials, mouth protectors, maxillofacial materials, restoratives (consisting of glass polyalkenoates or glass-ionomers and composites), adhesives, and sealants. Specifications and standards for dental materials are also briefly mentioned in the text. 

Silicones were also used for the preparation of finger prosthesis, in the case of loss of fingers because of trauma, congenital disorders and excision for neoplastic disorders. Although microsurgical reconstruction by reimplantation or transplantation can be attempted to restore function of many finger defects, it may not be possible in crush and severe injuries. Customized silicone prostheses have a wider rate of acceptance, owing to their comfort, durability and stain resistance, which are far superior to any other available extraoral maxillofacial materials [17]. 

ALUMMUMCOMPOUMDS - ALUMINIUMOXIDE(ALUMINA) - CALCINED, TABULAR, AND ALUMINATE CEMENTSl (Vol 2) -maxillofacial pENTAL MATERIALS] (Vol 7)... 

Denture Bases. Prosthodontics is involved with materials and techniques for the replacement of missing oral and extraoral maxillofacial tissues. A large part of prosthodontics involves replacing the teeth of edentulous patients, eg, making dentures. 

J. M. Antonucci, Transactions of the Academy of Dental Materials Proceedings of the Conference on Materials Research in Maxillofacial Prosthetics, 1992, pp. 136-155. 

Another important class of ceramic biomateiials is based on AI2O3 (aluminum oxide or corundum). These materials are bioinert and are widely used for the knob of replacement hip joints and other joint endoprostheses. Other uses include tooth-root implants, parts for osteosynthesis, maxillofacial implants, and skull surgeryAluminum oxide ceramics prepared for use as biomateiials must have a low concentration of impurities such as silicon oxide and alkaline earth oxides, which can interfere with the bioinertness of the implant. ... 

Other biomedical applications of polymers include sustained and controlled drug delivery formulations for implantation, transdermal and trans-cornealuses, intrauterine devices, etc. (6, 7). Major developments have been reported recently on the use of biomaterials for skin replacement (8), reconstruction of vocal cords (9), ophthalmic applications such as therapeutic contact lenses, artificial corneas, intraocular lenses, and vitreous implants (10), craniofacial, maxillofacial, and related replacements in reconstructive surgery (I), and neurostimulating and other electrical-stimulating electrodes (I). Orthopedic applications include artificial tendons (II), prostheses, long bone repair, and articular cartilage replacement (I). Finally, dental materials and implants (12,13) are also often considered as biomaterials. 

The TMDSC results for Examix silicone impression material and modulation condition (b) in Figure 16 are similar to those for the maxillofacial silicone in... 

There are two types of maxillofacial implants extraoral and intraoral. The former deals with the use of artificial substitutes for reconstructing defective regions in the maxilla, mandible, and face. Useful polymeric materials for extraoral implants require (1) match of color and texture with those of the patient (2) mechanical and chemical stability (i.e., material should not creep or change color or irritate skin) and (3) ease of fabrication. Copolymers of vinyl chloride and vinyl acetate (with 5 to 20% acetate), polymethyl methacrylate, silicones, and polyurethane rubbers are currently used. Intraoral implants are used for repairing maxilla, mandibular, and facial bone defects. Material requirements for the intraoral... 

Ni a, T. Concepts in biological analysis of resorbable materials in oro-maxillofacial surgery. Revista de Chirurgie Oro-Maxilo-Faciala i Implantologie, 2(1), 33-38 (2011)... 

S. A. Woife, Autogenous Bone Grafts versus AUoplastic Material in Maxillofacial Surgery, Clin. Plast. Surg., 9, 539-40 (1982). 

Wolfe SA. Autogenous bone grafts versus alloplastic material in maxillofacial surgery. Clin Plast Suig 1982 9 539-40. 

Sinclair, R.G. and Gynn, G.M. (1972) Preparation and Evaluation of Glycolic and Lactic Acid-Based Polymers for Implant Devices Used in Management of Maxillofacial Trauma. II, Battelle Memorial Institute, Columbus, OH. Sinclair, R.G. (1973) Slow-release pesticide system. Polymers of lactic and glycolic acids as ecologically beneficial, cost-effective encapsulating materials. Environ. Sci. TechnoL, 7 (10), 955—956. Manninen, M.J. and Pohjonen, T. 

Silicones and polyurethanes have been used to produce denture liner materials and maxillofacial prostheses. Most of these materials are silicone based, e.g., Flexibase, Molloplast-B, Prolastic, RS 330 T-RTV, Coe-Soft, Coe-Super Soft, Vertex Soft, PERform Soft, and Petal Soft. Other custom... 

S. Torgersen and N.R. Gjerdet, Retrieval study of stainless steel and titanium miniplates and screws used in maxillofacial surgery. Journal of Materials Science Materials in Medicine, 5, 256-262 (1994). 

Goldberg, A. J., Craig, R. G. Filisko, F. E. (1978) Polyurethane elastomers as maxillofacial prosthetic materials. Journal of Dental Research, 57, 563-569. 

Cutright, D.E., Hunsuck, E.E., Beasley, J.D. Ill (1971) Fracture fixation using a biodegradable material. Polylactic acid./. Oral Maxillofacial Surg., 29, 393-397. 

Vinyl Plastisols. These materials have some utility in maxillofacial prostheses. The formulations are viscous liquids, made up of small vinyl particles dispersed in a plasticizer, along with colorants. They are heated to generate the... 

Silicones. These materials have some only recently been used to produce maxillofacial prostheses. Both the RT- and heat-vulcanized materials may be used. Heat-vulcanized formulations are supplied as a semisolid or putty-like material, which requires the addition of colorants. The molded material is cured under pressure at 180°C/30 min. The heat-cured materials exhibit better strength and color stability than the RT-cured materials. 

Poiyurethanss. This is the most recent material used in maxillofacial applications. Fabrication requires accurate proportioning of the components. The isocyanate and polyol are blended, placed in a suitable mold, and allowed to cure at room temperature. Colorants and other additives are also used in the formulations. Even though the fabricated prosthesis has a natural feel and appearance, the final product is still relatively unstable. 

Soft-tissue Prosthesis. Several useful reviews adequately cover the present status and recent advances in materials for oral, maxillofacial, plastic, and reconstructive surgery. ... 

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