Masami Fujishita

Radiographic interpretation of so-called developmental defect of mandible

Ten cases of so-called development defect were detected on panoramic radiograms. One of them was bilocular, two were round, three were ovoid, and four were half-ovoid. Eight were in men and two were in women. These cystlike lesions are sometimes misdiagnosed as epithelium-lined cysts or benign tumors, such as ameloblastoma. For the detection of this kind of defect, panoramic radiography is available, and the lesion is differentiated from many cysts and tumors in the jaws by posteroanterior projection and occlusal films. From the published literature, some tendencies of age distribution and sex incidence were reviewed.

Clinicopathological study of odontogenic keratocyst

Fifty-five cases of odontogenic keratocyst in the mandible were classified into two subtypes according to the histopathologic characteristics of the epithelium (Group-1; the epithelium was parakeratotic with cuboidal or columnar, accentuated and palisadelike arranged basal cells, Group-2; the epithelium was orthokeratotic with a distinct stratum granulosum.) and were examined for the following four factors; 1) age distribution, 2) size of bone destruction, 3) degree of lateral bone expansion, and 4) features of the cyst contents. Most cases of Group-1 indicated radiographically lateral bone expansion and large cystic bone destruction and had fluid cyst content. On the contrary, the majority of Group-2 cases indicated no lateral bone expansion, were relatively small lesions, and their cystic cavities were filled with caseous materials.

The clinicoradiologic predictability of perforations of the soft tissue of the temporomandibular joint

One hundred thirty-one arthrographic examinations of temporomandibular joints were performed on 119 patients. The relationships between clinical symptoms, tomographic findings, and soft-tissue perforation were examined. Perforations of the articular disk or posterior attachment were revealed in 58 joints. Joints with crepitation showed a high frequency of perforation (20 of 22). Pain in the joint area and limitation of opening correlated to disk reduction. Perforations were observed in 12 of 21 joints with continuous pain. Osseous changes were detected in 89 joints. Joints with abnormal radiodensity (erosion, sclerosis) combined with abnormal shape (pocket erosion, osteophyte formation, deformity) showed a high frequency of perforation (41 of 45), which corresponded to 84% in this study. In those cases with osseous change or crepitation, positive predictive values of perforation were both 91%. These types of osseous change and their clinical significance might predict soft-tissue perforation with high accuracy before an arthrogram is performed.

Preliminary nuclear magnetic resonance studies on human saliva

Of gustatory-stimulated human whole, parotid, submandibular and sublingual saliva only parotid saliva, a serous rather than mucous secretion, presented a relatively well-resolved proton NMR spectrum with satisfactory signal-to-noise ratio in a short time (30 min). The proton signal intensities showed significant circadian rhythms related to the circadian rhythms of protein concentrations in saliva. Age- and sex-associated differences in spectra were not observed for healthy saliva. On the other hand, marked differences in the spectra were observed for patients with suspected sialoadenitis.

Correlation between radiographic and histopathological findings in squamous cell carcinomas of the gingiva

SummaryThe relationship between the radiographic features of jaw bone destruction and the histopathological features of tumor cells in 115 squamous cell carcinomas of the lower gingiva was investigated. The radiographic features were classified into four patterns as saucer-shaped, permeated, geographic and moth-eaten. Histopathologically, the cases were divided into three groups, a) the highly differentiated type showing papillary and nest structure well keratinized, b) the moderately differentiated type showing small cord and strand structure with moderate keratinization, and c) the poorly differentiated type showing marked cellular dissociation with poor keratinization. In the group of saucer-shaped, permeated, geographic and moth-eaten type, the proportion of histologically highly differentiated tumors was high. Namely, highly differentiated tumors tended to reveal a fairly mild and compressive resorption and poorly differentiated tumors showed more invasive and aggressive potential to the bone.This study suggested that the radiographic images of the mode of bone destruction in squamous cell carcinomas of the gingiva are influenced by the histopathological nature of the tumor cells.

Myxoma of the Jaws—report of six cases

SummaryClinical-radiographical analysis of six cases with myxoma of the jaws diagnosed histopathologically was attemped, and the following summary was obtained.1.All patients presented with either painless swelling or no symptoms, and it is suggested that myxoma of the jaws is not a rapidly growing and is a benign lesion according to their histories and clinical-radiographical findings.2.Radiographs of six cases showed rather variable appearances and needed to be differentiated from that of ameloblastoma, hemoangioma, giant cell tumor, fibrous dysplasia or dentigerous cyst.3.Though most of myxomas in the jaws are considered to be of odontogenic origin, odontogenic epithelium was found histopathologically in only one of five cases.

Large recurrent ameloblastoma

The ameloblastoma is the most common odontogenic tumor. It is usually described as a locally malignant lesion, because it has been characterized as a benign tumor with a marked tendency to recur. In a recent survey of the literature, t reatment by curettage was found to have resulted in a 50-90 per cent recurrence rate 1,2) and hemiresection in about a 10 per cent recurrence rate% The following two cases are unusual due to the long period elapsed before their recurrence after a hemimandibulectomy and in that they showed large recurrent lesions.

Radiographic features of chronic osteomyelitis of the mandible

ConclusionAs shown in the present cases, osteomyehtis varies in its radiographic appearance depending greatly on the stage of the disease at which the radiograph is taken, as well as the resistance of the tissue and the virulence of the infection.Therefore, when we make a radiographic diagnosis of osteomyelitis, it would be also of utmost importance to understand what type and what stage in the radiographic transition of chronic osteomyelitis are shown in mature consideration of the present status, history of the disease, age of the patient and any other factors.As shown in the present cases, osteomyehtis varies in its radiographic appearance depending greatly on the stage of the disease at which the radiograph is taken, as well as the resistance of the tissue and the virulence of the infection. Therefore, when we make a radiographic diagnosis of osteomyelitis, it would be also of utmost importance to understand what type and what stage in the radiographic transition of chronic osteomyelitis are shown in mature consideration of the present status, history of the disease, age of the patient and any other factors.

The integral dose in panoramic intraoral x-ray tube radiography

A Monte Carlo computer program was developed to estimate the integral dose to the head and thyroid for panoramic intraoral x-ray tube radiography. The advantage of this computer simulation is that it is able to avoid many of the difficulties associated with low-energy and low-dose x-ray dosimetry. The calculations were made for maxillary and mandibular projections separately, using 10 kv. increments between 40 and 60 kv. The results obtained were presented in terms of the integral dose per milliampere second. Typical integral doses for a routine examination of the head are 2.1 mJ. and 8.5 microJ for the thyroid during mandibular radiography and 1.7 microJ for the thyroid during radiography of the maxilla using 55 kv. and 0.5 mAs.

Monte carlo calculations of mean bone marrow dose and energy imparted from CT head scanner

Because of the potential for high radiation doses in CT procedures, the object of this study was to estimate the mean bone marrow dose and the energy imparted from a 3rd generation CT head scanning procedure using Monte Carlo simulation. The simulated and calculated mean bone marrow dose (μGy) and energy imparted (mJ) per 1cm slice thickness scan are as follows:Adult 120kV,effective mAs 553mAsChild 120kV, effective mAs 213mAs173-376μGy, 16.0-18.3mJ (Western)67-136μGy, 5.5-6.5mJ (Western)110-208μGy, 16.0-18.3mJ (Japanese)64-120μGy, 5.5-6.5mJ (Japanese)