Condylar position following mandibular advancement: Its relationship to relapse

Forty-one patients who elected to receive a bilateral sagittal osteotomy to advance the mandible were examined clinically and radiographically to assess condylar position preoperatively and at three specific times post-operatively. Parameters designed to measure changes in condylar and distal fragment position were located on tracings and digitized for statistical analysis. Changes in distal fragment position included advancement and clockwise rotation during the surgical interval and significant posterior relapse with continued clockwide rotation during the period of maxillomandibular fixation. A small amount of counterclockwise rotation associated with interocclusal splint removal was seen following fixation release. No significant condylar movement was seen during the surgical interval. During the period of maxillomandibular fixation, both condyles exhibited a significant superior movement, and the left condyle also moved posteriorly. No changes in condylar position were noted following release of fixation. The clinical significance of these condylar movements is not clear. Despite minimal changes, 18 patients, six of whom had had no preoperative symptoms and one of whom had exhibited reciprocal clicking, complained of temporomandibular joint pain or noise postoperatively. This suggests that maintenance of condylar position during surgery may not prevent temporomandibular joint dysfunction. In addition, the observed 37% relapse in surgical advancement in the absence of significant condylar distraction implies the interaction of other factors in the relapse process.     

The effect of preparation procedures on original canal shape and on apical foramen shape

With the use of clear casting resin, simulated curved canals were created so that canal preparation procedures could be directly visualized and compared. Regardless of the type of enlarging instrument or the technique used, undesirable characteristics were produced in all preparations that would make canal filling difficult. To modify the typical preparations, alteration of the enlarging flutes, use of rasping rather than rotation of the instruments, and a flaring technique are recommended.     

The image intensifier in oral and maxillofacial surgery

The mobile image intensifier has been found useful in the removal of foreign bodies from both intraoral and extraoral sites. The safety of the machine has been verified, and a technique for its application is described. Additional uses for the machine are stated.     

Pathologic evaluation of disc dysfunction and osseous abnormalities of the temporomandibular joint

The arthrographic findings in 141 patients with TMJ symptoms were compared with the linear tomographic evaluation to assess the incidence and severity of associated osseous abnormalities. Thirty-nine temporomandibular joints (28%) had significant osseous abnormalities compatible with degenerative joint disease. The incidence and severity of the degenerative changes compared favorably with the arthrographic assessment of the degree of soft-tissue injury. A cause-and-effect relationship between TMJ disc damage and dysfunction and degenerative arthritis is suggested.     

Operative management of 194 cases of combined maxillofacial-frontobasal fractures: Principles and surgical modifications

The treatment modalities and results of 346 cases of frontobasal and midface fractures, 194 of which had to be managed by surgery, are reported, and the operative results are evaluated. The importance of an early one-stage operative repair of combined frontobasal-maxillofacial fractures is stressed. The indications for the pure transethmoidal, combined transethmoidal-transfrontal, and single neurosurgical handling of these patients are analyzed. Important surgical modifications that are decisive in the operative management of these fractures are described.     

Crestal ostectomy and lateral wall compression for management of the enlarged pneumatized tuberosity

The crestal ostectomy with lateral antral wall compression is a simple, predictable procedure to correct soft tissue and osseous hypertrophy in the pneumatized maxillary tuberosity. It offers certain advantages over other techniques: 1) simultaneous reduction of vertical and lateral aspects of the hyperplastic tuberosity; 2) simultaneous revision of hypertrophic or mobile mucosal tissue overlying the tuberosity; 3) avoidance of a hrizontal scar band in the buccal vestibule, which may subsequently interfere with the denture flange; 4) negligible effect on the depth of the buccal vestibule; 5) fixation wires are not required; 6) rapid healing of the osteotomy site, since there is intimate bony contact; 7) expedient initiation of denture fabrication is possible because the palatal aspect of the tuberosity is not mobilized; and 8) no surgical stent is necessary.     

Use of the titanium-coated hollow screw and reconstruction plate system in bridging of lower jaw defects

Clinical results obtained with hollow titanium screws and reconstruction plates in the bridging of mandibular bone defects of 17 patients are described. Following implantation the newly forming bone establishes direct contact with the sprayed titanium surface of the screw and the underside of the plate and permeates the screw. The stability of anchorage therefore increases with the duration of implantation. The reconstruction system also allows salvaging of small fragments such as the condyloid process. The adjustable, individually shaped, mandibular condylar prosthesis permits precise restoration of articular guidance on the reconstructed side while preventing incorrect loading of the opposite joint. The clinical results confirm the recently published findings from animal studies.     

Perturbation of cobalt 60 radiation doses by metal objects implanted during oral and maxillofacial surgery

The influence on cobalt 60 dose distributions of typical metal parts used in oral and maxillofacial surgery was studied. Relative doses were determined by exposing x-ray films in a polystyrene phantom set-up containing samples of Vitallium, titanium, and stainless steel. Optical densities were converted to doses with the aid of sensitometric curves. The results show that for normal incidence there is a 25% to 40% increase in dose at the entrance side of the metal and a 20% to 25% decrease in dose at the exit side. The enhancement effect falls off rapidly and becomes negligible at about 1 mm from the interface. The reduction effect decreases more gradually and is still evident at distances of a few centimeters. These dose perturbations should be taken into account in the planning of radiation therapy for patients in whom metal objects have been implanted.     

The empty sella syndrome

Oral and maxillofacial surgeons, in the course of patient evaluation, may incidentally discover abnormalities of the sella turcica. A large percentage of patients with sella deformities will be found to have the empty sella syndrome. The clinical and radiographic manifestations of this disorder, and the significance of this diagnosis, are discussed.     

New concepts in the reconstruction of mandibular defects following tumor resection

The results of experiments with a new reconstruction plate used to bridge defects in irradiated and nonirradiated mandibles of dogs are presented. The principles of fixation of the plate with hollow titanium powder-sprayed screws and a titanium mesh for stabilizing the autologous cancellous bone are discussed. The direct contact between the surface of the screw and the bone, as well as proliferation of bone into the hollow screw, are demonstrated by light and scanning electron microscope studies. Autologous cancellous bone fixed with the new mesh leads to bridging of the defect even in irradiated areas.