The purpose of this study is to solve the influence of various developmental processes upon the granularity of the film. Factors which affect the granularity are the temperature of developer, the mixing method of developer, and whether an automatic processor is used or not.
The temperatures used in this study were 15°C, 20°C, 25°C and 30°C.
The mixing method of the developer was done by rotating films in the solution. The rotating velocity was from 0mm/sec to 117.8mm/sec.
Siemens Pantomat P-6 was used as an automatic processor and the films were EKTASPEED of Kodak.
Ag-particle size of film developed under each developmental condition was measured by the computer. The results were as follows.
1. As the temperature of the developer rose higher, the Ag-particle size of the film became larger and the film-speed also went up. But its granularity became worse.
2. It was understood that the mixing process of developer the Ag-particle size smaller. The filmspeed that was developed under 117.8mm/sec (which is the maximum rotating velocity), fell about 10% compared with that of the stationary tank development.
3. By using an automatic processor (roller type), the Ag-particle size became smaller in comparison with the stationary tank development.
4. The factor which mostly effect the film granularity was the developing temperature. It is considered that in the film developed in higher temperature, Ag-particles get entangled in each other to became larger granulation mottles, which makes the granularity worse.

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Secretory sialograms were analyzed on 32 healthy individuals (Group I) and 70 patients. The patients were categorized as follows.
Group IIa: 16 patients complaing of xerostomia with punctate or globular pattern on sialogram.
Group IIb: 25 patients complaing of xerostomia without abnormal pattern on sialogram.
Group IIIa: 13 patients having inflammetory symptom with sialographic abnormality.
Group IIIb: 16 patients having inflammetory symptom without sialographic abnormality.
Radiographic examination was carried out during the injection of contrast medium and 5, 15, 30 seconds after removing the catheter without stimulation. In some of them 60 seconds empty phase was examined.
The results of the present study include: (1) The image of the terminal duct disappeared earlier than that of the main and primary ducts in the overall group. However, the clearance rate of contrast medium in the terminal duct was not significantly different between each groups, at the empty phase of 30 seconds., (2) Clearance of the punctate and globular images were delayed compared with that of the duct system., (3) Considering the main duct width, the clearance rate was significantly different between group I and patient group (except for group IIIb)., (4) Considering the length, the clearance rate in the main duct was not significantly different between each group.

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One hundred and nineteen cases (124 cysts) of histologically confirmed dentigerous cysts were reviewed radiographically and the relationship to the periapical lesion of preceding deciduous tooth was studied.
The incidence was twice in male and rather higher in less than 20 years of age. The mandibular premolars were predisposing site.
Through the long-term records of clinical and radiographic informations, almost all the preceding deciduous tooth had received the endodontic treatments such as the vital amputation or pulpotomy. In addition, their roots were irregularly resorbed.
From the results, it is suggested that some kinds of inflammatory changes in the periapical area of the preceding deciduous tooth might play an important role in the dentigerous cyst formation.

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On dental radiograph, a thin radiopaque layer bordering tooth socket is called lamina dura, which is widely accepted as one of the landmarks on radiographic diagnosis. However, lamina dura may occasionally change without pathologic condition.
We experimentally studied about influence of factors related change of normal lamina dura using Mp-Mc system.
The results are as follows:
1. The change of lamina dura was quantified with the two parameters, lamina dura width and Al equivalent of lamina dura.
2. Exposure factors does not change lamina dura.
3. The change seems to depend on the geometric relationship between root shape and x-ray projection.
4. On the angle of the x-ray beam to the root, lamina dura of the flattening root of mandibular first molar is more changeable than one of the rounding root of mandibular second premolar. The more root shape is complex, the larger the change of lamina dura is.
5. It may be difficult to identify lamina dura at the apex of a root and arround a rounding root.

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We retrospectively reviewed the cases of 116 patients who underwent scintigraphy at the Okayama University Hospital Attached to Dental School. This study was done to learn more about the indications and the value of scintigraphy in the diseases of Oral and maxillo-facial region compared with CT scans and MR Imaging as well as conventional radiographic studies.
The ^99mTc-MDP bone images provided very useful information for evaluating the presence of bony involvement, metastases of the remoted areas and the recurrence of the malignant tumors which escaped detection by conventional radiographs.
In the cases of malignant tumors, tumor size was correlated directly with the degree of uptake of ⁶⁷Ga-citrate and small primary foci under the size of T1 did not result in a positive scan. The degree of abnormal uptake of ⁶⁷7Ga-citrate was correlated with the rate of the progression of malignant tumors, and ⁶⁷Ga-citrate scans very useful for assessing the surrounding tissue infiltration of the maligmant tumors. But ⁶⁷Ga-citrate scans provided less useful information in assessing metastases of the regional lymph nodes as compared with the usefulness of CT scans and MR Imaging.
While ^99mTc-MDP bone images and ⁶⁷Ga-citrate scans have proved most useful in the evaluation of metastases of the remoted ares and initial detection of the metastases depended entirely upon the scintigraphic findings in most cases.
The result of this study indicated that false positive findings by physiologic uptake and inflammation were seen in the areas of subauricular, submandibular and oral mucosa with ⁶⁷Ga-citrate and in the lower and upper jaw bones with ^99mTc-MDP bone images. These false positive uptake caused confusion to detect the malignant tumors. In inflammatory cases very active sites of infection accumulated enough ⁶⁷Ga-citrate as compared with chronic inflammation. In the cases of chronic osteomyelitis of mandible, the ^99mTc-MDP scans provided more subtle assessments of regional and total bony involvment of the inflammatory process as compared with that of conventional radiographic images. Thus, it was suggested that the use of scintigraphy might provide useful information for monitoring the pathological conditions of iniflammatory diseases.
^99mTc-pertchnetate was most useful to evaluate the functional status of salivary gland and ⁶⁷Ga-citrate was required for most effective evaluation of sialoadenitis. We found that the combined ^99mTc-pertehhnetate and ⁶⁷Ga-citrate scans provided most useful means of investigating the salivary gland tumors.

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Patient is a 44-year-old man with multiple myeloma of the left mandible. The radiogram showed multiple punched-out appearance in the skull plate and large ostolytic destruction of the left mandible. The Tc-99m-MDP bone scintigram of the whole-body revealed positive image in the left mandible, multiple ribs and lumbers, however the lesion of skull plate did not show positive image. The Ga-67 scintigram indicated weakly positive image in the left parotid region. According to the procedure of image diagnosis, the multiple metastatic lesions were detected. In conclusion, we discussed about the clinical evaluation of the diagnostic imaging of multiple myeloma.

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