Reinforcement of facial prosthetic dental stone molds.
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Acrylic Resins↗
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Results for “Maxillofacial Prosthesis”
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Functional impression technique in the management of an unusual facial defect: a clinical report.
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Eye, Artificial↗
In vitro testing of the bond between soft materials used for maxillofacial prostheses and cast titanium.
STATEMENT OF PROBLEM: The choice of soft materials for maxillofacial prostheses is important for covering extraoral defects after tumor surgery or radiation therapy. The use of cast commercially pure titanium as reinforcement seems to be a suitable option. PURPOSE: Making use of the advantages of titanium frameworks for maxillofacial prostheses requires exploring ways of combining it with soft materials. This study investigated such combinations and evaluated discoloration of the soft material to determine whether it was attributable to the titanium reinforcement. MATERIAL AND METHODS: Five soft materials used for maxillofacial prostheses and their bond strengths to cast titanium were tested. Different ways of conditioning the titanium surface and different adhesives were used. Plain mechanical retention was also studied. The Gretag SPM 100 was used to determine the potential effects on coloring after 24 hours of radiation in the Suntest rapid exposure unit. RESULTS: Suitable material combinations for bonding soft materials to titanium were found for all soft materials studied. Bond strength varied depending on the chemical basis of the soft material. Results indicated that maximal bond strengths were obtained by the combinations Supersoft with Super-Bond, Supersoft with subsequent silicoating, and bonding with Dentacolor connector. Few color shifts attributable to the titanium reinforcement were evident in the 2-mm layers of the soft materials applied. CONCLUSION: The results of this study showed that it is possible to combine a titanium framework and soft silicone materials.
Acrylic Resins↗
Accelerated color change in a maxillofacial elastomer with and without pigmentation.
STATEMENT OF PROBLEM: Maxillofacial prostheses require frequent replacement because the elastomer and its color additives undergo changes. PURPOSE: This study attempted to determine whether predictable color changes occur when 3 pigments are individually incorporated into a specific silicone elastomer. MATERIAL AND METHODS: The materials included an RTV elastomer; 1 natural inorganic pigment, burnt sienna; and 2 synthetic organic pigments, Hansa yellow and alizarin red. Eight test groups of 10 polymerized specimens were established. Groups 1 and 2, acting as the control, involved only the elastomer. Groups 3 and 4 were composed of elastomer and burnt sienna. Groups 5 and 6 consisted of elastomer and Hansa yellow. Groups 7 and 8 comprised elastomer and alizarin red. Odd-numbered groups were assigned to a test site in Miami, Fla., whereas the even numbered groups went to Phoenix, Ariz. Specimens weathered in Miami and Phoenix received sunlight exposures of 1305.7 MJ/m2 and 1310.2 MJ/m2, respectively, over time. Before and after weathering, the L* a* b* color parameter (DeltaE*) of each specimen was determined spectrophotometrically. RESULTS: Mean color changes that occurred in Arizona were larger than those produced in Florida. Specifically, these differences ranged from 0.4 (alizarin red groups) to 2.36 units for the 2 unpigmented control groups. Other differences showed significance for the unpigmented (P=.001), burnt sienna (P=.006), and Hansa yellow groups (P=.001). CONCLUSION: Outdoor weathering tests in which documented ASTM methods were used provided a valid baseline for future research on color changes in maxillofacial prostheses.
Analysis of Variance↗
Extraoral maxillofacial prosthetic rehabilitation at the M. D. Anderson Cancer Center: a survey of patient attitudes and opinions.
STATEMENT OF PROBLEM: Measures of satisfaction after extraoral maxillofacial prosthetic rehabilitation have been sparsely reported. PURPOSE: This article reviews the care-related opinions of patients who were provided extraoral prostheses at the M. D. Anderson Cancer Center over the course of 10 years. MATERIAL AND METHODS: A questionnaire was delivered to 263 extraoral prosthetic patients to elucidate their degree of satisfaction with several parameters, including prosthetic use, care, quality, durability, longevity, and cost. In addition, issues relating to self-image, socialization frequency, and income-earning ability before and after rehabilitation were surveyed. RESULTS: The views of 76 respondents demonstrated a general satisfaction with their prostheses. A majority believed that their prostheses fit comfortably, and most were satisfied with cosmesis. In addition, a preponderance of respondents reported no substantial alteration in social activity after rehabilitation. Although the number of respondents relying on their own employment fell by more than 50% after rehabilitation, nearly all reported a relatively static income before and after rehabilitation. CONCLUSION: The survey revealed a high degree of patient satisfaction with extraoral maxillofacial prostheses. Nevertheless, areas of potential improvement were not lost on the survey's population. The patients desired prostheses that last longer and have improved color stability. An interest in improved retentive mechanisms was mentioned by several patients, and only about half of the respondents perceived prosthetic cost to be completely reasonable.
Adult↗
Can we assess quality of life in patients with head and neck cancer? A preliminary report from the American Academy of Maxillofacial Prosthetics.
Survival statistics alone may no longer be valid when used as evidence of effective outcomes. Patient satisfaction is an end point that needs further evaluation and should be included in the outcomes assessment. A 133-item questionnaire has been designed by a special committee of the American Academy of Maxillofacial Prosthetics (AAMP) to assess the quality of life of patients with head and neck cancer impacting the orofacial region. This survey will be distributed to the entire population of 7 geographically dispersed treatment centers in the United States for a 2-year period. Patients will be stratified into several subgroups, including radiation/nonradiation, maxillary/mandibular, and surgical reconstruction/prostheses. Separate analyses will be conducted for each subgroup, and comparisons will be made within subgroups to test the sensitivity of the questionnaire to a known difference. A revised version of the AAMP questionnaire, limited to 50 items of interest to patients, will be validated against 2 established head and neck cancer questionnaires. This article provides background on previous quality-of-life studies and reviews the need for and aims of the AAMP assessment instrument.
Head and Neck Neoplasms↗
Physicomechanical and cytotoxic properties of room temperature vulcanizing silicone prosthetic elastomers.
The physicomechanical and cytotoxic properties of two newly introduced room temperature vulcanizing (RTV) silicone prosthetic elastomers, Ideal and Silskin 2000, were investigated. Another RTV silicone, Elastosil M3500, was also investigated as a potential facial material. The in vitro cytotoxicity was assessed with the agar diffusion test and mouse fibroblast cells (L929). The properties investigated were tensile strength, percentage elongation, modulus, tear strength, hardness, and color changes (deltaE*). The properties tested were selected because of their clinical significance in fabricating facial prostheses. The results indicate that Elastosil M3500 has a better combination of high tear strength, elongation at break, and low hardness than Ideal and Silskin 2000. All materials demonstrated a low cytotoxic profile. Elastosil M3500 warrants further attention with clinical trials.
Agar↗
Measurement of bone metal contact (BMC) in retrieved maxillofacial osseointegrated implants.
Eighteen screw-shaped extraoral osseointegrated implants retrieved from 10 patients were analysed by microradiography. Retrieved implants were trephined with a border of surrounding bone, fixed, embedded in epon plastic, ground and processed for microradiography. The reasons for retrieval were unexplained pain (n = 4), inability to cope with the implants (n = 2), fracture of central screw (n = 2), skin penetration problems (n = 1) and trauma (n = 1). The study group comprised six males and four females with a mean age of 53.4 years (range: 9-81 years). All implants were clinically stable at the time of removal, and mean osseointegration time was 3 years (range: 1-5 years). Six implants were removed from the temporal bone, five from the frontal bone and seven from the maxilla. Bone metal contact was estimated to vary between 27% and 83%. Bone metal contact was lower in the frontal bone compared to the temporal bone or maxilla, and was further reduced after preoperative irradiation. Longer osseointegration time increased bone metal contact, as did increased age up to 60 years. It is concluded that extraoral osseointegrated implants in humans may integrate morphologically as well as clinically. By microradiography it was possible to define bone metal contact in the region of implant installation.
Adolescent↗
The long-term impact of a training program in maxillofacial prosthodontics.
A follow-up survey of trainees in a National Cancer Institute-sponsored program in maxillofacial prosthodontics was conducted. Information about the trainees' current professional activities indicated that the majority work in private practice or a dental school, are primarily involved in clinical work or teaching, and see few cancer patients. Inadequate reimbursement and lack of collaboration with surgeons were cited as barriers to involvement in cancer patient care. It is suggested that barriers to applying training expertise in actual practice settings require emphasis in the planning and curricula of training programs.
Career Choice↗
Influences of different surgical procedures on growth of dentomaxillary complex in dogs with artificially created cleft palate.
Possible detrimental effects of palate repair on dentomaxillary growth have been reported before. In our study, two principally different surgical techniques were compared. Dogs with artificially created clefts of the palate were subjected to either a periosteal flap (Langenbeck) or to a bone flap (Dieffenbach) closure. Skull roentgenograms and upper jaw impressions were used to study the possible effects on growth. Definite abnormalities were found following both procedures; there are strong indications that the bone flap is the more detrimental one.
Animals↗
Custom-fabricated silicone implants for contour restoration.
A 15-year review is made of contour restoration by custom silicone inlay technique. Eighty-three patients have undergone surgery since 1962. The indications, preparation of moulage and implant, surgical technique, and care of complications are described. The custom silicone technque has proved successful, precise, and relatively free of complications. Tolerance of uncomplicated implants has been permanent.
Adolescent↗
Total midface reconstruction after radical tumor resection: a case report and overview of the problem.
We report an unusual repair of a massive midface defect resulting from resection of a recurrent squamous cell carcinoma of the nasal vestibule. The defect included both maxillas, the hard palate, the upper lip, and all nasal and perinasal tissues. After treatment, reconstruction was accomplished using prostheses and autologous tissue transferred from local and distant sites. The osseous component of the transferred tissue permitted placement of osseointegrated implants for fixation of maxillary and nasal prostheses. The rationale for this reconstruction and the problems associated with midface reconstruction after radical tumor resection are discussed.
Carcinoma, Squamous Cell↗
Dynamic cleft maxillary orthopedics and periosteoplasty: benefit or detriment?
In 1990, Drs Millard and Latham published their initial experience with dynamic maxillary appliances (DMAs) and periosteoplasty for children with cleft lip and palate. The technique provided for alveolar alignment and consolidation, with elimination of oronasal fistulas. Opponents to this approach speculated about impairments to facial growth. To date no longitudinal studies have been published. Over the last 10 years, 35 unilateral and 10 bilateral complete clefts have been treated with this technique. All patients have been followed and documented clinically, orthodontically, and radiographically. Cephalometric analyses were performed on children after the age of 6 years. The children have excellent facial aesthetics with well-balanced lips and noses. Radiographs demonstrate bone within the repaired alveolar clefts. Articulated impressions show anterior and lateral crossbites in the unilateral patients that improve over time and appear to be correctable orthodontically. The bilateral patients have satisfactory occlusions and arch forms. Cephalometric analyses confirmed no evidence of skeletal crossbites or midfacial growth retardation. This is a work in progress that will continue as the children grow. Although definite and final conclusions would be premature, it can be stated that to date all patients are following consistent and favorable growth patterns. Our team is confident in proceeding with this technique.
Alveoloplasty↗
Statistical investigation of mandibular dimensions for the planning of a series of mandibular corpus replacements.
The mandibular corpus height, the width measured at the height of the foramina mental and at a distance of 3 mm from the base, the mandibular corpus length and the mandibular angle were examined in 368 (185 male, 167 female, and 34 uncertain) intact, European anthropologic skulls. The differences between the left and right sides and the two sexes were evaluated. No significant difference was found between the two sides. The differences between males and females did prove statistically significant, but was considered unimportant with regard to the aim of planning a series of mandibular prostheses. The experimental data were broken down into five classes, and the class medians were taken to be the dimensions for the replacements. For a five-piece series, the relative percentage distribution of the class medians suggests the following proportions for production (mean -2SD and mean +2SD 6%, mean -SD and mean +SD 25% and mean 38%). Mandibles with these average dimensions can be chosen from the anthropologic collection, wax models of which may facilitate the planning of a series of mandibular corpus prostheses.
Adult↗
Biomaterials in the face: benefits and risks.
An extensive review of biomaterials in the face was conducted in an American Society of Maxillo-facial Surgeons-sponsored biomaterials symposium. The symposium was held in Boston, MA, immediately preceding the 1998 annual meeting of the ASPRS/PSEF. The scope of the symposium extended from current reconstructive techniques for the facial skeleton, including autogenous bone and biomaterials, to potential application of new techniques in molecular biology that may enable the body's own tissues to be engineered to provide bone and cartilage to reconstruct the facial skeleton. The authors review the presentations and relevant literature on biomaterials in the face. The following topics are reviewed: current reconstructive techniques using autogenous bone grafts, methyl methacrylate cranioplasty, demineralized bone, and hydroxyapatite; biomaterials used for rigid fixation, including metallic and bioabsorbable implants; biomaterials used for facial augmentation, including porous polyethylene, hard-tissue replacement, and ceramic biomaterials; biofilm, or a layered polysaccharide matrix secreted by bacteria on the surface of implants; and potential means of inducing bone formation by directing the body's own tissues through cytokine interaction, gene transfer, and tissue engineering.
Absorbable Implants↗
An algorithm for maxillectomy defect reconstruction.
A maxillectomy defect creates a communication from oral cavity to nasal cavity that may extend to the orbit. Functional deglutition and speech problems with a significant soft tissue deficit ensue. This paper defines the reconstruction options for the spectrum of inferior partial maxillectomy defects to midface-orbital exonerations. Treatment protocols from maxillectomy patients treated in January 1991 to February 1996 at a major tertiary care institution were reviewed (n = 108). An ascension of care from dental obturator, nonvascularized graft, local flap, regional flap, and free tissue grafts (n = 28) is described. These data and experience were organized to provide a treatment algorithm to assist in presurgical planning for maxillectomy reconstruction.
Algorithms↗
Advances in head and neck reconstruction.
There are numerous advances that have taken place over the last several years in head and neck reconstruction. In this article, the author has outlined three exciting developments. The first is in the area of palatomaxillary reconstruction using free tissue transfer. In select cases, depending on the nature of the defect, soft tissue flaps have been highly successful. However, in more extensive defects, the author chooses to transfer vascularized bone composite flaps to achieve successful dental restoration as well as closure of the palatal defect. Sensory restoration through the use of sensate flaps has been a topic of considerable controversy. The author presents his experience with three patients who underwent a unique reconstruction of the laryngopharynx that has demonstrated conclusively that targeted sensory restoration can be achieved through neural anastomoses. By anastomosing the sensory nerve to the superior laryngeal nerve, there are implicit physiologic implications with respect to the feedback that is achieved and its role in achieving glottic closure during deglutition. Extensive laryngeal reconstruction with subglottic involvement can be a very challenging problem. The author describes a new technique using vascularized tracheal autografts with the thyroid gland as a carrier. This provides the necessary ingredients for transferring a cartilaginous infrastructure within a thin layer of vascularized mucosa to restore the framework and the lining to the laryngotracheal region. Three patients have been restored who had extensive glottic and subglottic stenoses that have since been decannulated and are successfully eating as well as speaking. In addition, the author feels that this is a very promising technique for the management of chondrosarcomas, in which a significant portion of the cricoid arch requires reconstruction.
Bone Transplantation↗
The resistance of maxillofacial reconstruction plates to biofilm formation in vitro.
OBJECTIVES/HYPOTHESIS: Bacterial biofilms, bacteria surrounded by a protective glycocalyx, have been demonstrated on bioimplants placed within and outside of the head and neck region. The presence of the biofilm often makes decontamination of an infected implant impossible, requiring removal of the implant. Infections attributable to biofilm formation within the facial skeleton after reconstruction with implants may result in delayed union, fibrous union, malunion, nonunion, and malocclusion. These complications often require removal of the implant and secondary surgery. Although the incidence of infections necessitating implant removal is relatively low, the increased numbers of implants being placed make this a growing problem. Previous work in the authors laboratory has demonstrated a resistance to biofilm formation on different types of pressure-equalizing tubes. The hypothesis evaluated in the study is that such resistance to biofilm formation is due to the inability of bacteria to adhere to the tubes because of the material's smoothness or surface charge. STUDY DESIGN: A controlled observational study. METHODS: Scanning electron microscopy was used to evaluate the formation of biofilms in vitro for a common strain of Staphylococcus aureus on four implantable materials. The implantable materials included titanium and polylactide resorbable plates. RESULTS: Consistent with the authors' prior findings, they were able to produce bacterial biofilm reliably on a silicone pressure equalizing tube but were unable to demonstrate biofilm formation on the titanium or resorbable implants. CONCLUSION: The absence of biofilm formation on these implants can best be explained by the surface charge or polarity properties of these materials. These findings are consistent with the relatively low incidence of infections among patients receiving these implants in maxillofacial applications.
Biofilms↗