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Results for “Mandibular Prosthesis”

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PubMed1998

McCune-Albright syndrome progressing with severe fibrous dysplasia.

We present the case of an 11-year-old girl with McCune-Albright syndrome associated with severe fibrous dysplasia. In addition to bone lesions, she has apparent manifestations of precocious puberty. In examination, a mass at the mentum spreading to mandibular corpus bilaterally was seen. This mass has affected the mandibular teeth. It was nearly 20 x 20 x 15 cm in size and had local necrotic regions on it. The lower lip was expanded too much by the mass. Another mass filled the left maxillary sinus, expanding the left zygomatic region outwardly and closing the left nasal fossa completely. A rectangular skull shape was related to the involvement of cranial bones. After stainless steel, custom-made mandibular prosthesis was prepared, the patient underwent surgery. A partial mandibulectomy was performed, and resulting mandibular bone defect was reconstructed by steel prosthesis. Craniofacial involvement occurs in 100% of disseminated cases. In the dental literature, mandibular involvement was found in 20% of cases. However, in studied literature, we did not find a dramatic mandibular lesion as severe as that presented here.

Acute Disease↗
PubMed1998

Dental devices; effective date of requirement for premarket approval; temporomandibular joint prostheses--FDA. Final rule.

The Food and Drug Administration (FDA) is issuing a final rule to require the filing of a premarket approval application (PMA) or a notice of completion of a product development protocol (PDP) for certain devices, namely, the total temporomandibular joint (TMJ) prosthesis, the glenoid fossa prosthesis, the mandibular condyle prosthesis (for permanent reconstruction), and the interarticular disc prosthesis. At a later date, FDA will propose reclassifying from class III into class II the generic type of temporary mandibular condyle prosthesis intended for temporary reconstruction following surgical ablation of malignant and benign tumors. This action establishing the effective date of the premarket approval requirement for certain devices is being taken under the Federal Food, Drug, and Cosmetic Act (the act), as amended by the Medical Device Amendments of 1976 (the 1976 amendments), the Safe Medical Devices Act of 1990 (the SMDA), and the FDA Modernization Act of 1997 (FDAMA).

Device Approval↗
PubMedDate not supplied

Mersilene mesh chin augmentation. A 14-year experience.

During the past 20 years, a variety of alloplastic materials have been introduced for chin augmentation. Mersilene mesh (Ethicon, Sommerville, NJ), introduced in 1950, demonstrates many qualities that make it an ideal implant. This article reviews the senior author's (S.W.P.) successful 14-year experience using Mersilene mesh chin implants. Between 1983 and 1997, 264 patients underwent chin implantation procedures. The results show a low rate of infection (0.8%) and displacement (1.5%). There were 14 temporary paresthesias and no cases of permanent anesthesia. There were no incidences of absorption, rejection, or extrusion. Mersilene provides a soft, natural appearance to the chin, and it continues to be our choice for chin implantation.

Adult↗
PubMedDate not supplied

Resorption beneath silastic mandibular implants. Effects of placement and pressure.

OBJECTIVE: To evaluate the extent to which silicone rubber mandibular implant (Silastic; Dow Corning, Midland, Mich) pressure and placement (supraperiosteal or subperiosteal) affect underlying mandibular resorption. DESIGN: A randomized, controlled animal trial. SUBJECTS: Ten mixed-breed adult hounds. INTERVENTIONS: Each animal's mandible was implanted with 6 Silastic blocks, 3 inserted supraperiosteally and 3 subperiosteally. Within each grouping of 3 implants, pressure was varied from "minimum" to "moderate" to "maximum" by compressing the implant with titanium miniplates. After 4 months, the animals were killed and their mandibles sectioned for microscopic examination. RESULTS: Mandibular resorption occurred in varying degrees beneath all implants by the end of the study period. The extent of resorption was consistent with retrospective studies in humans. No statistically significant difference was found between supraperiosteal or subperiosteal placement of the implants. However, higher-pressure implants tended to produce less resorption than lower-pressure implants. CONCLUSIONS: While some bone resorption seems inevitable with Silastic mandibular implants, these results would seem to suggest that the placement of implants above or below the periosteum need not be a concern for the surgeon attempting to minimize this consequence. On the other hand, increased pressure may actually decrease resorption, contrary to current assumptions.

Animals↗
PubMed2004

Comparison of miniplates and reconstruction plates in mandibular reconstruction.

BACKGROUND: The aim of this study is to compare complication rates of miniplates versus reconstruction plates in the fixation of vascularized grafts into segmental mandibular defects. METHODS: Retrospective analysis of 143 consecutive successful microvascular composite flaps performed between 1993 and 2001 was performed. Data were gathered from a computerized database, case notes and pathology reports. Complications were classified as dehiscence, infection, plate or bone removal. RESULTS: In the series, 49% of patients received miniplates, and 51% received plates. No significant differences in complication rates were found between those grafts fixed with miniplates (27%) and those with reconstruction plates (30%). Plate choice was primarily determined by consultant preference. No significant differences were found in patient, defect, treatment, or follow-up characteristics between the plate groups. Twenty-nine percent of patients had at least one late complication at the reconstructed site, and this was higher (39%) in those who had postoperative radiotherapy. CONCLUSIONS: No evidence was found in this study that the increased rigidity offered by reconstruction plates influences the rate of plate or bone removal, infection, or plate exposure. Thus, the decision to use reconstruction or miniplates is not dependent on the rate of plate complications.

Adult↗
PubMed2004

[Mandibular reconstruction with autologous bone and osseoinductive implant in the Göttingen minipig].

BACKGROUND: Direct mandibular reconstruction with an autologous bone transplant was compared with an osteoinductive implant following an extensive continuity resection of the lower jaw in Göttinger mini-pigs. METHOD: In nine full-grown mini-pigs a one-sided continuity defect (5 cm) was created in the lower jaw. In four animals it was filled with a 50 x 25 x 15 mm(3) collagenous carrier enhanced by rhBMP-2 (400 micro g/cm(3) rhBMP-2). In two animals only the carrier was implanted as a control. Three animals received the resected autologous bone as a free transplant. Bone regeneration and consolidation of the defects was analyzed radiographically and histologically. RESULTS: Following implantation of the osteoinductive implant, complete osseous consolidation of the continuity defect in the lower jaw was observed in all animals. The defects were completely filled with a biomechanically stable bone which showed signs of functional adaptation. The replantation of the orthotopic autologous bone did not lead to functional stability quickly enough. In the periphery only an incomplete bony bridge was formed which was interrupted by large pseudarthrosis. No consolidation of the defects was found in the control group (carrier alone). CONCLUSION: Direct reconstruction of an extensive, biomechanically loaded defect with an osteoinductive implant proved to be the superior method. The osseous regeneration observed shows an immediate functional orientation. The necessity for extensive adaptive remodeling is thus minimized.

Animals↗
PubMed2005

The outcome of various cements in combination with titanium reconstruction plates after segmental resection of the mandible.

We report on 82 patients who had segmental resection of the mandible and immediate reconstruction with titanium plates, which were supplemented by polymethylmethacrylate cement (n=32), glass ionomer cement (n=27), silicone (n=9), or nothing (n=14). The mean (S.D.) follow-up time was 92 (26) months. Six months after operation, 27 (46%) of the plates with polymethylmethacrylate cement or glass ionomer cement were removed. During the same time period, four (28%) of the plates were removed in the group with no additional material and two (22%) in the group that had silicone. There was a significant difference in survival time of the metal between the group with silicone and the group with glass ionomer cement (p=0.014, log rank). Although silicone performed slightly better than the reconstruction plate on its own, we doubt whether any cement is necessary.

Aluminum Silicates↗
PubMed2004

Mandibular reconstruction using the titanium functionally dynamic bridging plate system: A retrospective study of 34 cases.

PURPOSE: We sought to examine the use of the Titanium Functionally Dynamic Bridging Plate System (Howmedica Leibinger, Freiburg, Germany) for mandibular reconstruction after oncologic resection in 34 patients. PATIENTS AND METHODS: A retrospective study of 34 patients who had mandibular reconstruction using the titanium dynamic bridging plate system for mandibular reconstruction after oncologic resection were evaluated. The indications and postoperative outcomes were studied. Our evaluation focuses on the tolerance and aesthetic and functional results of this system. RESULTS: The follow-up ranged from 1 to 4 years. At the end of the study, 18 of the 34 patients (53%) still had the plate in place. One plate fracture and 1 plate exposure requiring surgical management were found. Surgical results were satisfying, particularly when looking at healing delay or long-term tolerance. Aesthetic (79% rated the results as good or acceptable) and functional results of this reconstruction material were satisfying. CONCLUSION: This reconstruction system provides a solution for a safe and rapid mandibular reconstruction for patients with a poor prognosis or poor general condition. This method also preserves the possibility of secondary reconstruction.

Adult↗
PubMed2004

Design and fabrication of custom mandible titanium tray based on rapid prototyping.

UNLABELLED: During the past few years, the combination of medical imaging and rapid manufacturing technique has proven to be a very important development. On the other hand, the conventional method has some drawbacks. For example, it takes longer time to complete an operation and it also presents some difficulty in matching the repaired contours. With advanced software and hardware, an image of an undamaged bone similar to that of the patient can be made from computerised tomography (CT); and a physical object constructed by the mirror-processed image data can be quickly fabricated with a high degree of fitting with the patient's bone. This paper presents a methodology for the design and fabrication of an individual titanium tray for the repair of mandible defects. Methods for the tray modeling using CAD system are presented: A 3D model of the bony defect is generated after the acquisition of helical CT data. An individual tray is designed using freeform surfaces geometries and fabricated by rapid prototyping (RP) technology. The results of tray filling with bone-grafting materials are then presented. RESULT: the tray is inserted into the patient mandible segment. The symmetry and reconstruction quality contour of the repaired mandible was satisfactory. Thus, the patient is able to eat normally. The bone-grafting material harvested from the anterior ilium was low. The clinical experience showed that rapid prototyping and reverse engineering software are effective methods of fabricating custom trays for mandibular reconstruction after bone loss due to a tumor.

Adult↗
PubMed2002

Reconstruction of lateral mandibular defects with dynamic bridging plates.

The principle of mandibular reconstruction by dynamic bridging plates in association with a bone graft is based on the double bridge reconstruction method. However, the plate can be used alone. Our aim was to report the long-term results of this treatment for mandibular lateral defects in fragile patients. From 1993 to 1999, 38 consecutive patients had primary reconstructions with bridging plate for lateral mandibular defects. Their mean age was 58.4 years (26-86) and the mean follow-up was 50 months (6-89). Excluding removal of plates for local recurrences, the overall success rate was 78%. Plates were removed after a mean of 20.4 months (1-66). No plates fractured. Dynamic bridging plates allow an immediate and efficient reconstruction with reduced operating time and compare favourably with conventional plates. They can also be used as a stand-by for patients who are to have a delayed free flap reconstruction.

Adult↗
PubMed1997

Individual prostheses and resection templates for mandibular resection and reconstruction.

This new technique uses helical computed tomography data and computer-aided design and manufacturing for preoperative fabrication of individual mandibular prostheses together with corresponding resection templates. Coherent 3D geometries for computer-based models are the basis for the construction of prostheses and provide data for a computerized numerical control fabrication. Fixation plates are fabricated with the titanium prostheses. The identical data of these plates are used for the computer-aided design and manufacturing of resection templates, which guide an oscillating saw in a precisely determined resection plane. This plane again is identical with the prostheses' margins for mandibular body replacement. The use of this technique in four patients is reported on: after temporary insertion of the templates for resection and after resection, the prostheses were stabilized with the same screws in the same screw-holes where the templates had been. Resection and reconstruction were thus highly precise, safe and fast and primarily led to excellent aesthetic and functional results. Wound-healing depends on a safe soft-tissue reconstruction over these large prostheses. Coverage with flaps seems obligatory. In spite of the superior technical aspects, the clinical long-term results of this new technique were poor.

Adult↗
PubMed1998

Augmentation genioplasty with hard tissue replacement implants.

PURPOSE: This study assessed the soft tissue changes produced by the placement of hard tissue replacement (HTR) polymer chin implants for augmentation genioplasty and evaluated the dimensional stability as well as any bony changes associated with the implants. PATIENTS AND METHODS: The study group consisted of 18 patients (3 males, 15 females) with an average follow-up of 21.5 months (range, 12 to 44 months). All implants were placed through an intraoral incision and stabilized to the symphysis with a single 2.0-mm diameter titanium screw. Preoperative, postoperative, and long-term cephalometric radiographs were analyzed for changes in soft tissue thickness in the chin region, implant stability, and the presence of bone resorption. RESULTS: The net hard tissue chin augmentation achieved averaged 6.0 mm (range, 4.5 to 9 mm). Average preoperative soft tissue thickness was 12.1 mm (range, 11 to 14.5 mm) and postoperatively it was 10.6 mm (range, 10 to 13.5 mm). The average increase in soft tissue projection was 77.6% (range, 71.4% to 83.3%) of the implant thickness. There was no radiographic evidence of implant migration or bony resorption beneath the implant. CONCLUSIONS: HTR implants appear to be a predictable means of augmenting the chin, providing the desired aesthetic change, without causing resorption of underlying bone.

Adolescent↗
PubMed1998

Functional reconstruction of the mandible: a modified titanium mesh system.

This paper describes a method for mandibular reconstruction utilizing autogenous cancellous bone in a titanium mesh. The mesh is designed preoperatively based on a duplicate of the patient's mandible which is modified to simulate an anatomically correct edentulous segment in the region to be reconstructed. The duplicate mandible is articulated with a maxillary dental cast, and a locating splint is fabricated for intraoperative use to aid the positioning of the mesh in relation to the upper teeth. The method facilitates future rehabilitation with dental implants and results in a symmetric and highly functional reconstruction of the mandible.

Adult↗
PubMed2001

Importance of chin evaluation and treatment to optimizing neck rejuvenation surgery.

The chin is the keystone linking the aesthetics of the face and neck but is often neglected in the analysis. Procedures related to the chin play an important role in defining neck anatomy. Alloplastic implants can provide the illusion of a longer jaw line in a patient with retrogenia. Even greater anatomic changes to the neck result when a sliding genioplasty is performed. This effect is primarily due to the digastric attachments from the mentum and mastoid. Advancing the mentum may have a more direct effect of elevating the position of the hyoid, which sharpens the angle between the jaw and neck. Finally, the diagnosis of a witch's chin is also discussed for the patients who present for aging neck surgery.

Chin↗
PubMed2001

Surgical options for aesthetic enhancement of the neck.

A slender neckline is recognized as an attractive feature of youth. With aging, laxity develops in the skin and subcutaneous tissues that results in blunting of the cervicomental angle. Many surgical options are available to restore definition to the neck region. This article reviews the methods used to evaluate the appearance of the mentocervical area and also outlines the algorithm used by the senior author to surgically enhance its appearance.

Chin↗
PubMed2001

Comprehensive approach to rejuvenation of the neck.

A comprehensive rejuvenation of the neck depends on accurate analysis of the lower face and neck with attention to the contours and deep-lying structures. Although many surgeons address the well-recognized changes in skin and soft tissue that occur with aging, we believe bone resorption is also an important component. Loss of bone volume leads to loss of support for the soft tissues of the face. The result is soft tissue ptosis and loss of angularity between the various planes of the face. Initially, there is loss of the submental shadow and loss of height of the mandibular ramus. The gonial angle loses its prominence, and the chin becomes ptotic. The line of the body of the mandible is further obscured by the appearance of jowls. As the mandible shrinks, the submandibular gland as well as the muscles that make up the floor of the mouth are pushed inferiorly. For loss of bone support, implants tailored to the areas of deficit and to the aesthetic goals are used. These implants used for the mandible are tridimensional structures made from beaded polyethylene material. This restores the bone volume and provides good support for the soft tissues. We routinely perform a deep-layer cervicoplasty. This involves removing fat from the subplatysmal layer and between the anterior bellies of the digastric muscles. The digastric muscles are plicated toward the midline. The platysma muscle is separated from the underlying submandibular gland. Ptosis of the submandibular gland is treated by suspension of the fascia with sutures or imbrication of the overlying muscle. A short corset platysmaplasty brings the platysma muscles to the midline. Above the level of the hyoid bone, the digastric muscles are included in the sutures. If the patient has an obtuse cervicomental angle, but good-quality skin, there may be no need to perform skin resection. In these patients who are candidates for nonexcisional cervicoplasty, we routinely place a neck suspension suture. Patients with poor skin quality or excessive skin on the neck and jawline will require an excisional cervicoplasty or cervicofacial rhytidectomy. We have obtained consistently good results using this comprehensive approach.

Chin↗
PubMed2005

Chin and prejowl augmentation in the management of the aging jawline.

The effects of aging in the lower face and neck are reflected in the contour of the jawline. Soft tissue atrophy, the formation of jowls, and retrusion of the chin are all age-associated changes that contrast starkly with the smooth harmony of a young lower face. These soft tissue changes in the jawline are exacerbated by the effects of aging on the bony portion of the mandible. Bone resorption of the mandible seen with aging can lead to the development of a hypoplastic mentum and the formation of an anterior mandibular groove. Rhytidectomy serves to address the soft tissue changes from aging but cannot counter the effects of aging on the bony mandible itself. Understanding the effects of bone resorption on the aging mandible allows the facial plastic surgeon to augment the mandible appropriately to achieve a more effective rejuvenation of the lower face. The aging process in the mandible and the development of the prejowl sulcus are reviewed. The use of chin and prejowl augmentation as a valuable adjuvant to facelift surgery is discussed.

Aging↗