Nario Matsumoto

The assessment of trigeminal sensory nerve paraesthesia after bilateral sagittal split osteotomy: modified somatosensory evoked potentials recording method

Trigeminal neurosensory impairment is frequently observed following orthognathic surgery. The purpose of the present study is to visualize the degree of trigeminal nerve impairment following bilateral sagittal split osteotomy (BSSO). Twenty patients who underwent BSSO were in the present study. To record the modified somatosensory evoked potentials (SEP), two electrostimulation clips were applied. One clip was placed on the mucous surface of the lower lip and the other was placed on the skin surface. Each contact surface contained a separate 2 mm diameter silver anode and cathode attached to a 5 x 15 mm basement plate. The results obtained using this method revealed that complete recovery from neural impairment was observed in 7 cases (36.8%) on the right operative side and 4 (20.0%) on the left side at 6 months postoperatively. A definite delay in latency was observed on the left operative side at all the examination periods. The recovery period evaluated by the SEP method was longer than that of the objective two-point discrimination thresholds. Clinical records obtained showed considerable implications for trigeminal nerve function after BSSO.

New cephalometric images with a workstation: A preliminary report

OBJECTIVE This study was designed to test the feasibility of several types of enhancements for cephalometric computed radiographs through use of the Fuji Computed Radiography system (Fuji Photo Film Corp., Tokyo, Japan). STUDY DESIGN The material consisted of four lateral cephalograms made with the Fuji Computed Radiography system that were enhanced by varying the gradient levels before processing by means of both A-type (straight gradation) curves and workstation-type (peaked) curves. The four workstation-type images were set with optical densities at the peak of the curve at 1.5, 1.7, 1.9, and 2.1. Ten observers evaluated eight anatomic landmarks comparing pairs of workstation-type images. The best workstation-type image was then compared with the A-type image for the same landmarks. RESULTS For the four workstation-type images the best visualization of the anatomic landmarks was seen with workstation-type image 3, which had a maximum optical density of 1.9. Image 3 was also superior to the results of A-type image processing for most of the landmarks. CONCLUSION Image enhancement with the application of a computed radiography system is effective for study of lateral cephalograms.

Study of bacteria isolated from infections of the oral and maxillofacial region. Part 3: Relations between the clinical symptons and the isolation of organisms.

A total 150 patients with obstructed abscesses in the oral and maxillofacial region were studied with respect to the relation between clinical symptons and the isolation of organisms.Various kinds of anaerobes were isolated from almost all patients. Mixtures of grampositive cocci and anaerobic gram-negative rods were most frequent in severe cases. Patients in whom few organisms were isolated were characterized by chronic, mild inflammation and prior chemotherapy. All patients with postoperative maxillary cysts had chronic infectionsThe results suggested that anaerobes were necessary for the occurrence of infection in the oral and maxillofacial region and that pathogenic synergy between gram positive cocci and gram negative rods contributed to increased severity of infection.

Study of bacteria isolated from infections of the oral and maxillofacial region. Part 2. Anaerobes.

Eighty-six cases of obstructed abscesses in the oral and maxillofacial region were studied bacteriologic ally.Isolated anaerobic organisms were identified in detail and assessed with regard to antimicrobial susceptibility to several agents. Anaerobes were isolated from approximately 95% of cases that had isolated organisms. Gram-positive cocci, including Peptostreptococcus and Gemella, and gram-negative rods, including Prevotella, Porphyromonas, and Fusobacterium, were isolated frequently. As for antimicrobial susceptibility, some strains of Prevotella were resistant to β-lactam agents. In particular, many strains of Fusobacterium were resistant to erythromycin. Clindamycin and levofloxacin were highly active against anaerobes isolated from infections in the oral and maxillofacial region.Our results suggest that anaerobes as well as Streptococcus should be considered when treating infections in the oral and maxillofacial region.

Beneficial Effects by Modification of Surgical Method and Intra-postoperative Care

Bilateral sagittal splitting osteotomy occasionally involve the paresthesia of the mental nerve area. In the present study, postoperative complication, especially neurosensory disturbance has been investigated after modificatioin of the surgical method and intra-postoperative care. According to patient questionnairing, the period of neurosensory disturbance was almost within 6 months for the participants who underwent the osteotomy, with the vertical line on premolar. But some of them suffered a neurosensory disturbance period of more than two years. After 1992, we changed the vertical osteotomy line from premolar to molar region. Recovery of thermoreception and nociceation were early, but most cases of nociceation was not abnormally shown. Mechanoreception recovered between 2 weeks and6months, and no patients suffered neurosensory disturbance longer than 6 months.In addition, the amount of setback was found to be related to the recovery period of neurosensory disturbance.