A pathohistological study was made with use of 63 Wistar-strain rats on the behaviour of tongue tissue after cryosurgery. The freezing temperatures chosen were -50℃, -100℃ and -160℃ for 60 seconds. The results were as follows : 1. Epithelial tissue degenerated and disappeared to the 5th day after freezing, and the beginning of regeneration was on the 7th day after freezing. To the 22nd day, conjunction of epithelial tissue was restored. 2. To the 3rd day after freezing, breakdown and disapperance of the muscular bundles developed in the muscular tissue at the center of the frozen area. Arrangement and runing of muscular bundles were recovered on the 22nd day. 3. To the 5th day after freezing, blood vessels fell into breakdown and disappearance, and thrombus covered a wide area extending to the zone of muscular tissue. On the other hand, small blood vessels began to regenerate about the same time. 4. In the groups of below -100℃, thrombus was found in larger vessels and in wider areas than in the group of -50℃. 5. When larger vessels were frozen, these vessels fell into thrombus ; therefore, secondary injury of distal tissues was found. 6. Nerve tissues in the area of freezing fell into degeneration. Degeneration became severer to the 3rd day after freezing. Regeneration of nerve fibers began from the 5th day. Restoration of nerve distribution was on the 14th day in the group of -50℃, and on the 22nd day in the other groups. 7. Degeneration of nerve fibers extended to the larger nerve bundles in the medial and deep regions of the tongue. And this appearance was more remarkable and extended to the distal region in the groups below -100℃ than in the group of -50℃. 8. Regeneration of nerve fibers and recovery of nerve distribution were delayed in the groups of lower temperatures under -100℃ 9. Under the freezing temperature of -50℃, tongue tissues fell into degeneration, breakdown and disapperance at the center of the frozen area. These findings were found in wider areas in the groups of lower temperatures. 10. The tongue healed with a scar centering around the frozen area and with more remarkable deformation of the tongue in the groups under -100°.

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The radiographic examination of the maxillary sinus pathosis is usually accomplished by the Waters' projection, postero-anterior projection, and computed tomography. However, some lesions, such as the mucous retention cyst, post-operative maxillary cyst, and maxillary sinus carcinoma, as well as some lesions extending into the maxillary sinus, may be shown by panoramic radiography. In this study the detection of a globular radiopaque mass in the maxillary sinus of dry skull was compared experimentally using Waters' projection, postero-anterior projection, and panoramic radiography. Oil-clay masses with diameters of 5mm, 7mm, and 10mm were used as globular radiopaque masses, and they were always placed on the internal surface of the left maxillary sinus. The results obtained were as follows : 1. Globular radiopaque masses with diameters of 5mm, 7mm, and 10mm on the anterior wall of the maxillary sinus were detected in the sinus by every radiographic technique, but their correct positions were not clear. 2. Globular radiopaque masses with diameters of 5mm, 7mm, and 10mm on the posterior wall of the sinus were better shown by panoramic radiography. In panoramic radiography it was possible not only to detect a small radiopaque mass with a diameter of 3mm on the posterior wall, but also to determine its correct position in the sinus. 3. Globular radiopaque masses with diameters of 5mm, 7mm, and 10mm on the medial wall of the sinus were better shown by postero-anterior projection. But a globular radiopaque mass with a diameter of 3mm on the medial wall was not detected in the sinus. 4. Globular radiopaque masses with diameters of 5mm, 7mm, and 10mm on the floor of the sinus were better demonstrated by postero-anterior projection and panoramic radiography. In panoramic radiography, especially, it was possible not only to detect a globular radiopaque mass with a diameter of 5mm on the floor of the sinus, but also to determine its correct position on the floor of the sinus. A globular radiopaque mass with a diameter of 5mm on the floor of the sinus was also detected by postero-anterior projection, but its correct antero-posterior position on the floor was not clear. 5. Waters' projection is clinically utilized for the radiographic examination of the maxillary sinus pathosis. But it seems that Waters' projection is less effective for detection of globular radiopaque masses in the maxillary sinus. A radiopaque globular mass, especially on the floor of the maxillary sinus, is not clearly detected by Waters' projection, because of the overlapping of the maxillary molar teeth.

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Periodontal diseases and arthrosis of temporomandibular joint attributed to inadequate crown or bridge have recently been increasing. To prevent these diseases the functional performance of the prosthesis should be checked by temporarily cementing for some period prior to final fixation. However, very few descriptions were found on the elevation of the crown or even on the film thickness with temporary luting cements for that purpose. In this study, therefore, the elevation of the crown by cementation with temporary and permanent luting cements was examined using experimental crown and abutment tooth models. The space between the crown and abutment was approximately 30μm both at the axial and occlusal plane when the crown was seated on the abutment without cement. The decreasing rate of the elevation of the crown with time under loading was significantly different among the cements, suggesting that the outflow of the cement slurry from the crown margin might be markedly affected by its thixotropical behavior and particle size as well as its consistency. As for the effect of the particle size, it seemed rational to refer the maximum size of the residual particles after setting rather than that of the original powder particles. The temporary luting cements used were devided into two groups showing elevations as small as 4 to 14μm and more than 120μm, respectively. On the other hand, the elevation with the permanent cements ranged from 6 to 47μm. The applied load and load initiation time for cementation affected the elevation. No significant changes were found in the elevation if the load application was started within one minute after the end of mixing. It was also found that the load of 5 kg was sufficient for minimizing the elevation by cementation. The results indicate that in order to check the functional performance of the prosthesis prior to final fixation it is essential to properly select the temporary cement showing compatible elevation with the permanent cement to be used.

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Granular convoluted tubules of rat submandibular glands contain many kinds of physiological active peptides, namely NGF, EGF and some proteases, such as kallikrein, tonin, and so on. Recently, many kinds of trypsin-like proteases with different isoelectric points (pI) have been found in the homogenate of the rat submandibular gland, although they were only fractionated with electrofocusing. Two types of TAMEases which hydrolyze p-tosyl-arginine methyl ester (TAME) were thus purified by gel filtration, and DEAE ion-exchange chromatography and high-performance liquid chromatography and then their properties were investigated in this paper. The results obtained were as follows ; One TAMEase with pI 5.2 had a molecular weight of 28, 000 consisted of two subunits with molecular weights of 20, 000 and 8, 000, whereas the other TAMEase with pI 6.1 was of 32, 000. The former (pI 5.2) hydrolyzed TAME, TLME, BAPA and H-Pro-Phe-Arg-MCA, but not BTEE, whereas the latter (pI 6.1) hydrolyzed TAME and weakly TLME and BAPA but not H-Pro-Phe-Arg-MCA or BTEE. pH optima of the activities of two TAMEases for TAME were at 8.5 and temperature optima of the activities of two TAMEases for BAPA were around 50℃. TAMEase (pI 5.2) was strongly inhibited by soybean trypsin inhibitor, leupeptin, PMSF, TLCK, whereas TAMEase (pI 6.1) was weakly inhibited. Both TAMEases were not inhibited by PCMB at all. TAMEase (pI 6.1) was activated by 20μM of EGTA, although it was markedly inhibited by 10nM of Zn^<2+> ion. TAMEase (pI 5.2) was slightly activated by 1mM of Cd^<2+> and Mn^<2+> and cleaved 42K band, which resulted in a major band of 39k and minor bands of 37K, 34K and 32K. The 42K band was identified as actin by the method of Western blotting. TAMEase (pI 6.1) also cleaved 42K band without EDTA, and 52k band, still unidentified, in the presence of 20μM EDTA. The pH optimum of these cleavages was at 7.5. Anti TAMEase (pI 6.1) IgG did not form any precipitin line with TAMEase (pI 5.2), whereas anti TAMEase (pI 5.2) IgG did a slight precipitin line with TAMEase (pI 6.1) with a spur formation between anti TAMEase (pI 5.2) IgG and TAMEase (pI 5.2). By the indirect immunofluoresence method, these TAMEases were found to localize in the granular convoluted tubules of the submandibular glands of rats. TAMEase (pI 5.2) was nearly identical to PSR-V described by lkeno et al., although minor differences were observed between them, whereas TAMEase (pI 6.1) was partly similar to tonin, although there is no report on the esteroprotease activity of tonin inhibited by the very low concentration of Zn^<2+> ion. Both TAMEases might cleave a cytoskelton protein and actin, and TAMEase (pI 6.1) with EDTA might only cleave an unknown 52K band when the physiological active enzymes were secreted into the blood stream, although the physiological roles of the two types of TAMEase have not yet been fully clarified.

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熱可塑性注入充填法による根管充填を評価する目的で, ユニテックオブチュラデリバリーシステムを用いて抜去歯10歯に根管充填を行い, X線写真および走査電子顕微鏡による根管各部(根中央部, 根尖1/3部, 根尖部)の充填状態, ガッタパーチャのアピカルシートへの到達状況の観察を行った.X線写真による観察では, シーラーの有無にかかわらず根中央部と根尖1/3部の根管充填状態は5例中4例が良であった.しかし, 根尖部ではシーラーを使用すると5例中5例が良であったのに対し, 使用しなければ5例中2例が不良であった.ガッタパーチャのアピカルシートへの到達は, シーラーを使用した場合Flushは1例で, 残り4例はOverであった.シーラーを使用しなかった場合Flushは3例で, 残り2例はunderであった.電顕による観察では, シーラーの有無にかかわらず根中央部と根尖1/3部の根管充填状態は5例中4例が良で, 残り1例がやや不良であった.しかし, 根尖部ではシーラーを使用した場合5例中3例が良で, 残り2例がやや不良であったのに対し, 使用しなかった場合5例中1例が良, 残り4例はやや不良であった.

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The state of root canal obturation at various portions of the canal after the use of ultrasonic vibration for root canal irrigation was examined in this study. Ten extracted human teeth were used and the canals were filled by two methods, lateral condensation method (LCM) and vertical condensation method (VCM). Degree of canal obturation and reaching of the gutta-percha to the apical seat were examined on radiograms and obturation of various portions of the canal (mid-canal, apical third, and root apex) was observed by scanning electron microscope. The results were as follows : 1. On radiograms, obturation was good at the mid-canal portion in four cases out of five cases. At the apicai third and root apex portions, obturation was good in all cases for LCM. For VCM, obturation was good at mid-canal portion in three cases out of five cases. At the apical third and root apex portions, obturation was good in four cases. 2. Reaching of the gutta-percha to apical seat was "flush" in four cases out of five cases and one case was "under" for LCM. For VCM, the cases varied widely with cases of "flush", "over" and "under". 3. Scanning electron microscopically, obturation was rather poor or poor at the mid-canal and apical third portions in many cases for both LCM and VCM. At the root apex portion, obturation was good in four cases, and rather poor in one case for LCM. For VCM, obturation was good in one case, and rather poor or poor in four cases.

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This study was designed to examine root canal cleansing effect produced by combined use of NaOCl and EDTA of various concentrations. The commercial preparation of each was analyzed quantitatively and diluted with distilled water ; the concentrations of NaOCl were 1.25%, 2.5% and 5%, and those of EDTA 1.875% 3.75% and 7.5%. Extracted maxillary and mandibular anterior teeth and mandibular premolars with the root canals untreated were employed. Enlarging and preparation of the root canals were made with K-files after the root canals were filled with distilled water. Then the root canals were given 1-minute irrigation with 2 ml of NaOCl holded in the syringe with a standard needle, and continuously with EDTA. In another group the same irrigation procedure was made with distilled water. Inner wall surfaces were observed through scanning electron microscope. The results were as follows : 1. when the canals were cleansed with water only, or with 1.25% NaOCl and 1.875% EDTA, smeared layer was observed ni mid-canal and root apex ; the root canal could not be cleansed sufficiently. 2. when the canals were cleansed with 2.5%-5% NaOCl and 3.75%-7.5% EDTA, cleansing effect was sufficient at mid-canal, but insufficient at root apex. 3. In order to increase cleansing effect on root canals, abundant use of the irrigation agents appears to be necessary.

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The enamel thickness of upper central incisor in different facial contour types was measured as a guideline of enamel reduction for porcelain laminate veneer technique. The enamel thickness was 0.42±0.07mm at the cervical portion, 0.75±0.10mm at the middle portion and 0.83±0.01mm at the incisal portion. No significant differences in thickness were found among the different facial contour types. The results indicate that the enamel reduction should be at most 0.3mm around the cervical portion up to the crest of curvature in preparation for this technique although 0.5mm reduction might be allowed in other portions. The enamel thicknesses of mesial and distal portions showed good correlation with that of facial middle portion. Therefore, it is possible to estimate the reducible facial enamel thickness from the mesial or distal thickness through the radiographic examination.

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エプーリスは歯肉部に発生する良性の限局性腫瘤を総称した臨床診断名である.近年, 医療機関の増加に伴い, 早期に治療を受ける場合が多いため, 小豆大から拇指頭大までのものが多く, それ以上のものは少ない.最近, われわれは, 43才, 男性の下顎前歯部に発生した大きな線維腫性エプーリスの1例を経験したので, その概要を報告した.

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