Tore Arwill

A qualitative microradiographic study of the ename and the dentine in ground sections of impacted human permanent teeth

52 totally or partially embedded teeth were studied in ground sections by soft microradiography to assess the quality of the enamel and the dentine. In 79 % the dentine was more or less globularly mineralized. In 50 % the dentine-enamel junction (D.E.J.) was more scalloped than normally and in three cases the border-forming globules were vacuolated. All kinds of hypoplasia were found, gross, minor, and tube. The enamel-cementum junction was irregular in 63 %, hypoplastic in 60 %, hypomineralized in 42 %, and provided with loose enamel globules in 27 %. Cementum or bonelike tissue covered the enamel lingually in two front teeth and occlusally in a third lower molar. The fissures could be extremely narrow and penetrate the enamel till near the dentine border. The distance between the fundus of the fissure and the D.E.J, was measured to 0.15-0.5 mm, is one case only 0.06 mm. In their basal parts the fissures could be invaginated or ampullar. T-hypoplasia could be found in the walls or the fundus of the fissu...

Epidermolysis bullosa hereditaria

Abstract Pathologic alterations of the teeth and tooth germs in one case of epidermolysis bullosa hereditaria dystrophica polydysplactica and two cases of epidermolysis bullosa hereditaria letalis are described. The chief features were an intense proliferation of the outer and inner enamel epithelia, metaplasia of the ameloblastema to a stratified squamous epithelium at the onset of the mineralization process, and formation of epithelial whorls and vacuoles containing epithelial debris, partly mineralized, in the tooth sac, the outer and inner enamel epithelia, the stellate reticulum, the stratum intermedium, and the enamel stroma. In microradiograms the mineralized content of the vacuoles appeared as a conglomerate of mineralized globules, joined by a less mineralized substance, within or outside the enamel. The enamel matrix was hyaline, lamellar, or sometimes globular. A prism structure was found only in one case, and then only in a few sections. The thickness of the enamel was about one twelfth to one eighth the normal thickness. The enamel of the permanent tooth germs was strongly folded. The folds appeared helical in the tangential sections. Some roots in the dystrophic case were folded. The dentinoenamel junction was even in the deciduous teeth but folded in the permanent teeth. There were hemorrhages in the tooth sac and stellate reticulum. Rich proliferations of the capillaries were seen around the tooth germ.

Follicular choristoma of the gingiva: A peculiar lesion

Abstract In a 9-year-old girl a tumorlike nodular projection lingual to the lower permanent incisors contained sebaceous cells, hair follicles with hairs, a small keratocyst, melanocytes, and lymphocytes and plasmocytes, and, associated with disintegrated sebaceous cells, a foreign-body giant-cell reaction. The “tumor” is termed a follicular choristoma .

A NEW ROUTINE IN HISTOPATHOLOGY

The positive artifacts are informative in diagnostic work, but the negative ones are usually detrimental in thatthey interfere with the interpretation of tissue changes. Positive artifacts may be exemplified by the nuclear staining reactions in histology, and by the coloured precipitates, indicating enzyme activities, in histochemistry. Negative artifacts may be represented by the loss of stainable substances and by morphological defects usually from chemical and thermal damage during paraflin embedding, and diffusion problems and mechanical defects during freezing and thawing of tissues in enzyme histochemical studies. The methods used today in routine histopathology are extensively based on fixation and paraffin embedding of the tissues. Most of the procedures have been unchanged for many decades. The reluctance to introduce variations in the laboratory routine maintains the continuity of criteria for morphologic evaluation of tissue changes and thus simplifies the training of pathologists.

Histochemical tests on lipids in the oral and skin epithelia in the mouse

SummaryThe present study concerns the application of a new tissue transport medium, Histocon, in lipid histochemical analysis of biopsies. It was generally found that this medium visibly retained more lipids quantitatively than did a fixation of the tissues. The lipid “preserving” capacity of Histocon seemed to be superior even to the use of fresh frozen specimens. These beneficial effects may be due to membrane stabilizing factors in the transport medium.Two types of lipids were usually found when comparing oral mucosa with epidermis. The mucosa was characterized chiefly by phospholipids with an increasing concentration gradient towards the stratum granulosum. The skin showed, in addition to the similar phospholipid gradient, also the presence of unsaturated hydrophobic lipids in the stratum corneum and granulosum.

Die Epidermolysis bullosa hereditaria dystrophica mit Oesophagusveränderungen

ZusammenfassungZwei Fälle von Epidermolysis bullosa hereditaria dystrophica polydysplastica mit Oesophagusveränderungen werden beschrieben. Der eine Patient, ein 32 jähriger Mann, hat eine Stenose im oberen Drittel des Oesophagus. Der andere, ein 19 Monate alter Junge, hatte Schleimhautveränderungen, die hauptsächlich im unteren Drittel des Oesophagus lokalisiert waren. Diese hatten keine klinischen Beschwerden verursacht und wurden erst bei der Sektion entdeckt.Eine Literaturübersicht über die Oesophagusveränderungen bei E.b.h. wird tabellarisch wiedergegeben. Im ganzen sind früher 16 Fälle in der Literatur beschrieben.In einer darauf folgenden Diskussion wird die Ätiologie der Oesophagusveränderungen bei Epidermolysis bullosa behandelt.Zwei Falle von Epidermolysis bullosa hereditaria dystrophica polydysplastica mit Oesophagusveranderungen werden beschrieben. Der eine Patient, ein 32 jahriger Mann, hat eine Stenose im oberen Drittel des Oesophagus. Der andere, ein 19 Monate alter Junge, hatte Schleimhautveranderungen, die hauptsachlich im unteren Drittel des Oesophagus lokalisiert waren. Diese hatten keine klinischen Beschwerden verursacht und wurden erst bei der Sektion entdeckt.

Hyaline bodies and odontogenic epithelium in the follicles of unerupted permanent human teeth

In 58 embedded teeth and 126 follicles it was found that the enamel-forming epithelium could be heavily disturbed especially in narrow fissures and at the cemento-enamel junction by premature reduction preventing the enamel from being fully mineralized. The congestion of capillaries in the connective tissue of the follicle caused hemorrhage which imbibed the epithelium and the enamel stroma. In the follicles two types of hyaline bodies could be discerned. One type consisted of hyalinized islands of odontogenic epithelium. They could calcify and constituted a fluent transition to odontogenic tumors, e.g. odontoma and dentinoma. They were PAS positive and elastin negative. The other type (the Rushton type) consisted of white thrombi in congested capillaries in inflamed areas. They were PAS negative and elastin positive. The described mechanism might explain the caries susceptibility in molars and premolars with narrow fissural pits and grooves. The same is valid for the cervical areas when the enamel epithe...

The significance of the innervation of the predentine

Abstract 1. 1. Nerve fibrils may exist in large numbers in the predentine zone of teeth of persons aged 50 to 70 years. 2. 2. This condition may be pathologic and lead to pictures similar to damaged and regenerating peripheral nerve fibrils. 3. 3. The claviform or fusiform swellings of nerve fibrils in the predentine may be due to degeneration or regeneration and may simulate nerve endings. 4. 4. From the facts that (a) nerve fibrils do not exist at all in the vicinity of the predentine at an embryonic stage, (b) they exist but occasionally in this tissue in young persons and, (c) they exist abundantly in the secondary predentine of older persons, it is deduced that the enclosure of the nerve fibrils in the predentine is due to advancing years, pathologic conditions, or both. 5. 5. The diversity of opinion concerning the innervation of the teeth may thus be partly ascribed to a tendency to draw general conclusions from too little material and to disregard the dynamics of the tooth.