Biomedical subjects
Publications and source records attributed to B N Epker.
Arteriovenous malformations of the mandible are rare and potentially life threatening lesions. They are very unusual in young individuals. A case is reported in which a form of surgical treatment is advocated that permits preservation of the continuity of the mandible and the dentition with little potential for life threatening bleeding.
It is commonly assumed that nasorespiratory function can exert a dramatic effect upon the development of the dentofacial complex. Specifically, it has been stated that chronic nasal obstruction leads to mouth breathing, which causes altered tongue and mandibular positions. If this occurs during a period of active growth, the outcome is development of the "adenoid facies" (dentofacial morphology). Such patients characteristically manifest a vertically long lower third facial height, narrow alar bases, lip incompetence, a long and narrow maxillary arch, and a greater than normal mandibular plane angle. These dentofacial traits have repeatedly been attributed to restricted nasorespiratory function. It is generally believed that environmental factors can exert subtle or dramatic effects upon dentofacial morphology, depending upon their magnitude, duration, and time of occurrence. The purpose of this article is to present a critical review of the literature concerning the effect of one such environmental factor, nasal airway function, upon dentofacial morphogenesis. This review will critically examine the most frequently cited papers reporting a relationship between nasorespiratory function and dentofacial morphology. In summary, this critical review fails to support a consistent relationship between obstructed nasorespiratory function and the adenoid facies or long-face syndrome. Additional objective evaluations of this relation are encouraged.
Mandibular autorotation is a generally accepted cephalometric phenomenon that occurs when surgical superior repositioning of the maxilla is planned. This investigation was undertaken to determine whether autorotation of the mandible is a biologic phenomenon as well. Fifteen adults with vertical maxillary excess who underwent a mean surgical superior repositioning of 6.2 mm. were evaluated with cephalometric, kinesiometric, and electromyographic instrumentation immediately before and 3 months following surgery. Five persons selected at random from the original group (who also underwent a mean surgical superior repositioning of 6.2 mm.) were similarly evaluated 24 months following surgical intervention. The results of this study, which were analyzed by the Wilcoxon Matched-Pairs Signed-Rank test, revealed that a significant compensatory autorotation of the mandible occurred by the third month and was still constant 2 years later. We propose, on the basis of this preliminary evidence, that an "occlusal programming feedback mechanism" within the central nervous system mediated the compensatory autorotation of the mandible following surgical superior repositioning of the maxilla.
The kinesiometric and electromyographic findings from the evaluation of mandibular resting posture in 30 individuals with diverse vertical dentofacial morphology can be summarized as follows: 1. The RVD and TESP of the mandible are two distinctly different biologically dynamic neuromuscular entities. They differ with respect to their spatial position in that the RVD is 2.6 mm closer to centric occlusion than TESP. 2. The intrapersonal reproducibility of the RVD and TESP at various time intervals predictably demonstrated some biologic variability. 3. The occlusal neuromuscular mechanism apparently maintains a functional tone in the masticatory musculature at the RVD as a result of stimuli from the periodontal mechanoreceptors following tooth contact. 4. A physiologic range of neuromuscular adaptability exists within each diverse morphologic group. Adaptations are apparently mediated by the central nervous system and the musculoskeletal complex. 5. The interocclusal distance at the TESP is inversely related to the vertical dentofacial morphology. 6. Sophisticated computerized morphometrics in combination with the kinesiometric and electromyographic findings of this study demonstrate the dentoalveolar nature of VME and VMD and suggest that correction of these dentofacial deformities by various biologically compatible means will tend to normalize neuromuscular-skeletal relations.
One hundred consecutive cases were reviewed from two centers for correction of dentofacial deformities following simultaneous mobilization of the maxilla and mandible. The mean length of surgery was 5.15 hours, twenty patients received blood transfusions, and the mean length of hospitalization was 3.6 days. No patients experienced significant airway embarrassment requiring emergency procedures. An increased incidence of relapse, compared to single-jaw procedures, appears to be associated with these procedures. This study suggests that the simultaneous mobilization of both jaws should not be done without due consideration to specific indications and treatment planning. In select cases, with careful treatment planning, meticulous execution of surgical techniques, optimal supportive anesthesia, and postoperative care, the simultaneous mobilization of both the maxilla and the mandible can be achieved with few adverse sequelae and complications.
Simultaneous mobilization of the maxilla and mandible is indicated for the optimal correction of specific dentofacial deformities, as discussed in the preceding publication. Because of the added complexity of this type of surgical-orthodontic treatment, it is important to determine the absolute need for surgery and to construct a detailed blueprint of the specific changes to take place at the time of surgical intervention as well as those to be made by the orthodontist prior to initiation of any treatment. The intent of this article is to describe a technique of treatment planning which includes cephalometric prediction tracings, model surgery, determination of orthodontic-surgical sequencing, splint construction, and specific sequencing of surgery. When followed, these guidelines will enable the surgeon and the orthodontist to accurately determine the need for simultaneous mobilization of both the maxilla and the mandible and provide more predictable and stable results when it is performed.
The changes in external nasal morphology or nasal esthetics which accompany total maxillary surgery are often favorable. However, select patients who would otherwise benefit optimally from total maxillary surgery experience worsening of nasal esthetics secondary to the surgery. In our experience, this is primarily due to widening of the alar bases. The purpose of the present article is to identify those persons who will undergo undesirable nasal esthetic changes with total maxillary surgery and recommend a method of avoiding these changes.
As improvements in diagnosis, treatment planning, and surgical techniques have evolved it has become increasingly more common to consider simultaneous mobilization of the maxilla and mandible in order to achieve optimal correction of selected dentofacial deformities. In the experiences of the authors, there are patients with specific deformities of the Class III, Class II, Class I, and asymmetry types who can benefit from simultaneous mobilization of both jaws. It is the purpose of this article, the first in a series of three, to detail those specific conditions which warrant consideration for simultaneous mobilization of the maxilla and mandible. In the second article the details of treatment planning for simultaneous mobilization of the maxilla and the mandible will be presented, and in the third article the results of treatment in 100 consecutive cases will be evaluated.
Basic descriptive principles governing mandibular growth have been discussed. These principles were applied to evaluate growth changes after mandibular advancement surgery in 15 patients with idiopathic mandibular retrognathism. Subsequent mandibular growth proceeded in a downward and backward direction in all cases. This pattern of growth is not seen normally in patients with a low or median mandibular plane angle type of facial morphology. Since the functional biomechanical vector of force in the condylar-ascending mandibular ramus complex was changed surgically, it is postulated that this affected the subsequent pattern of mandibular relocation. A hypothesis for the specific manner in which surgical alteration of the basic biomechanics of mandibular function can deliberately affect subsequent mandibular growth direction is presented. Case reports are used to illustrate these effects. Further animal and clinical studies are currently underway to better elucidate the hypothesis put forth herein.
Sixteen individuals between the ages of 10 and 16 years who underwent superior surgical repositioning of the maxilla to correct vertical maxillary excess and were followed up for at least one year after surgery were evaluated. Follow-up ranged from 12 to 78 months with a mean of 36.7 months. The effects of subsequent growth on the esthetic, occlusal, and skeletal results achieved immediately following surgery were evaluated through analysis of profile esthetics, dental occlusion, and skeletal changes which occurred from the immediate postoperative period to longest follow-up examination.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Despite recent innovative technical and biological advances, surgical advancement of the mandible does not demonstrate uniform skeletal stability. In fact, the results of recent investigations have shown that considerable skeletal relapse occurs quite early in the post-surgical period. This article reviews current literature to implicate the factors primarily responsible for early skeletal relapse following surgical advancement of the mandible via the modified sagittal split ramus osteotomy. Three specific mechanisms which commonly predispose this orthognathic procedure to skeletal relapse are delineated. Prolonged skeletal stabilisation with control of the proximal segment of the mandible is advocated to insure predictably stable results.
A surgical technique for transoral exposure and secondary repair of the inferior alveolar nerve via a sagittally split mandible is described. The use of this approach in certain individuals enables the maxillofacial surgeon to perform a minor resection and re-anastomosis or major resection and autogenous grafting. This procedure provides adequate exposure for re-anastomosis of minor inferior alveolar nerve injuries under minimal tension and without a facial scar. However, postoperative intermaxillary fixation is required for four to six weeks.
Explore the source record for details and available documents.