Chapter 4 : Injury and the Recovery Reaction due to the Penetration of Material into the Mandibular Canal

A root canal filling material paste, mainly made of calcium hydroxide and iodoform with the addition of silicone oil, was experimentally introduced into the mandibular canals of dogs. The tissue reactions to the paste were examined by radiography, histopathology, and electron microscopy. The examination results showed that the paste was phagocytosed by macrophages and, in general, was gradually resorbed by the passage of time. The paste was also found to cause heterotopic calcification and/or bone formation within the limited area of original penetration. The histopathological tissue changes of the alveolar nerve tissue were also examined. No injury-related histopathological change was observed as long as the injected paste did not contact alveolar nerve tissue, but tissue damage was observed at sites of direct contact. After removal of degenerated nerved debris by macrophages and Schwann cells, the persisting external membrane or “Schwann tubes” appeared to provide a scaffold for axonal regeneration and Schwann cell proliferation.Editor, Toshiyuki KawakamiLanguage Editor, David M Carlsonviii, 232 p. ill. (some col.

形態計測のためのメタノール・硝酸セルロースによる組織包埋法

Very recently we developed a new embedding medium, "Shiojirin-E", made chiefly of cellulose nitrate (Kawakami et al. 1995)^&;t;1\u272)>. During the course of its development, we noted that cellulose nitrate would be a very suitable embedding medium for morphometric analysis, especially because of its low and constant rate of contraction. But the highviscosity of this medium resulted in a very slow rate of infiltration. Therefore we sought to develop a new, better histological embedding medium for morphometric analysis based on information on the methanol-cellulose nitrate method by Seki (1937)^. After trial and error, we succeeded in our goal : The composition of the medium is as follows : cellulose nitrate 15.0g, methanol 78.6g, and others 6.4g (total of 100.00g). When the specimens are not so big, we can easily get 3-5 micron-thick sections like paraffin sections with complete non-contractibility. We believe that this new methanol-cellulose nitrate medium will be useful especially for histological morphometrical analysis

Light and Electron Microscopic Studies of Microcalcifications Appearing in Monomorphic Adenomas

Microcalcifications appearing in two cases of monomorphic adenomas were studied histopathologically, electron microscopically, and electron-microanalytically. One case was basal cell adenoma that occurred in a 56-year-old man and the other was canalicular adenoma in a 71-year-old woman. The calcified granules were observed both in the lumina formed by the tumor cells and in the stromal tissues. The surroundings of the granules were stained by alcian blue and showed a sulfur peak by EPMA. These facts suggest that the surroundings contain sulfated glycosaminoglycans and that sulfur has a significant role in the mechanisms of pathological calcification as well as physiological calcification

Chapter 1 : Root Canal Treatment and the Role of Filling Materials

Endodontics includes diagnosis and treatment as well as management of pulpal and periapical diseases. Treatment aims to reduce inflammation of the periapical tissues, to dissolve remaining organic material, and to counteract coronal microleakage in the root canal through the use of medication and mechanical instruments. Finally, irrigated root canals should be obturated with filling material and sealer to prevent reinfection.Editor, Toshiyuki KawakamiLanguage Editor, David M Carlsonviii, 232 p. ill. (some col.

Amyloid Deposition in Human Pulp

A tooth with a pulp having a rare degenerative change was found among numerous extracted tooth specimens. Microscopically eosinophilic dimunutive granules existed around vesseles in the coronal pulp. These were stained positively with Congo red and periodic acid-Schiff. Electron microscopic observation revealed that granules were composed of bundles showing one of the characteristic appearances of amyloid deposition

Chapter 5 : Deciduous Tooth Resorption after Overfilling of Root Canal Filler: Function and Nature of Multinucleated Giant Cells

There are numerous reports on physiological root resorption claiming that the root resorption process of primary teeth is regulated in a manner similar to bone remodeling [28]. However, complex histological changes occur under several pathological conditions. Abnormal tooth resorption could be found in primary teeth due to certain causes until the completion of the permanent dentition. In Japan and eastern Asia, calcium hydroxide paste with silicon oil added iodoform is widely used for endodontic treatment of deciduous teeth. This material is sometimes excessively filled within root canals, and pathological reactions have been already discussed in previous sections. In this part, the influences on deciduous tooth endodontic therapy will be described in detail. The most characteristic feature is abnormal tooth resorption via osteoclast-like multinucleated giant cells (MGCs) and foreign body giant cells (FBGCs). In the later part of this section, the characteristics of foreign body type giant cells will be discussed through in vivo experiments.Editor, Toshiyuki KawakamiLanguage Editor, David M Carlsonviii, 232 p. ill. (some col.

Chapter 2 : Tissue Reaction to Root Canal Filling Material Embedded Subcutaneously in Rats

The reaction of subcutaneous connective tissues to root canal filling material pastes, made chiefly of calcium hydroxide, has been studied by means of radiography, histopathology, and electron microscopy. Radiography has revealed that embedded paste displays a well-demarcated radiopaque mass just after embedding, then gradually disappears over time. The resulting images have shown granulation tissue appearing, as well as and the phagocytosis by macrophages and giant cells, as observed histopathologically. Furthermore, there have been heterotopic calcifications within the proliferating granulation tissues in some cases, with electron microscopic examinations revealining phagocytosis. In the present study, the ultrastructural aspects of initial calcification in rat subcutaneous tissues elicited by root canal filling material paste, made up of calcium hydroxide and iodoform with the addition of silicone oil, were examined. The embedded paste caused heterotpic calcifications, which can be divided into two types: dystrophic calcification; and matrix vesicle calcification, which resembles that of bone tissue. These data suggest that the paste may elicit the differentiation of osteoblasts and/or cementoblasts from mesenchymal cells in periodontal ligament.Editor, Toshiyuki KawakamiLanguage Editor, David M Carlsonviii, 232 p. ill. (some col.

Chapter 3 : An In Vivo Examination of the Fate of the Components of a Root Canal Filling Paste made of Calcium Hydroxide and Iodoform with Silicone Oil

Using radioactive compounds, we investigated the fate of the calcium hydroxide and dimethylpolysiloxane (silicone oil) components in a root canal filling paste. The paste was made of calcium hydroxide and iodoform with the addition of silicone oil. Whole body, light, and electron microscopic autoradiographic surveys were used. Additionally, quantitative analysis using a liquid scintillation spectrometer was performed on the component dimethylpolysiloxiane. The calcium component moved to the bone tissue through the body fluid and blood, and some of it was excreted through the digestive tract. The calcium came partly from the calcium components of the paste in both types of heterotopic calcifications: dystrophic and matrix vesicle. Some of dimethylpolysiloxane component also passed into the digestive tract. Furthermore, the dimethylpolysiloxane played some part in the calcification caused by the embedded paste.Editor, Toshiyuki KawakamiLanguage Editor, David M Carlsonviii, 232 p. ill. (some col.

Characteristics of Clinical and Imaging Findings of Epidermoid Cysts under the Skin of the Mental Region

Epidermoid cyst often arises in the fl oor of oral cavity; however, it is relatively rare to arise subcutaneously in the mental region. We reported characteristics of clinical and imaging fi ndings of epidermoid cysts under the skin of the mental region. The patient was a 53-year-old male. He complained of a subcutaneous mass without pain in the left mental region. A palpable soft and movable thumb-sized mass without pain was observed at the fi rst examination. Ultrasound examination revealed a well-demarcated mass with heterogenous hyper-echoic internal echo and posterior echo enhancement. On power Doppler sonography, a small amount of blood supply was found around the periphery of the mass. Plain CT scan revealeda globular soft-tissue mass with peripheral high and central low CT values area. The mass was removed under local anesthesia using intraoral approach. A histopathologic diagnosis was epidermoid cyst. Recurrence is not observed 2 years after surgery. There were only 3 reports of epidermoid cysts in the mental region, including our case in Japan, clinically characteristics of age ranging 20 to 66 years of age and the mean age of 46 years, with 2 males and 1 female. The size wasfrom 20 mm to 12 mm in diameter and from the tip of a thumb up to the tip of a small fi nger. Ultrasound images of the inside of epidermoid cysts that we experienced this time showed enhancement of relatively uniform hyperechoic image and posterior echo, which was characteristically slightly diff erent from fi ndings of epidermoid cysts generally reported

含歯性嚢胞より生じた原発性骨内歯原性癌腫

Malignant tumors arising from dentigerous cysts are classified as primary squamous cell carcinoma derived from an odontogenic cyst or as odontogenic carcinoma according to the 2005 WHO classification and are extremely rare. We report a malignant tumor arising from a dentigerous cyst in the right maxillary anterior teeth , together with a literature review. The patient was a 75-year-old man who visited a hospital with complaining of discomfort in the lingual part of the right maxillary anterior teeth. On panoramic radiography and plain computed tomography (CT), dentigerous cyst, keratocystic odontogenic tumor or ameloblastoma was suspected. The extirpated material was histopathologically diagnosed as an odontogenic carcinoma (in situ) arising from the dentigerous cyst. Postoperative ultrasonography (US) and contrast enhanced CT revealed no metastasis to the cervical lymph nodes. The patient is currently being followed up without resection or anticancer drug administration. Neither local recurrence nor metastases were observed 18 month after surgery.症例は75歳男性で、右上顎前歯の舌部不快感を主訴として受診した。パノラマX線撮影とCT検査により含歯性嚢胞、角化細胞歯原性腫瘍またはエナメル上皮腫が疑われた。切除切片の病理組織学的検査の結果、含歯性嚢胞より生じた歯原性癌腫と診断した。術後超音波検査と造影増強CT画像では頸部リンパ節への転移は見られなかった。抗癌剤投与はせずに経過観察中で、術後18ヵ月時点で再発や転移は見られていない。含歯性嚢胞より生じる悪性腫瘍は2005年のWHO分類によれば歯原性嚢胞由来の原発性扁平上皮癌または歯原性癌腫に分類され、極めて稀である。本症例は右上顎前歯の含歯性嚢胞より生じた悪性腫瘍であった。他の症例についても文献レビューした