摘要:

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 fissure and the lingual aspect of the front teeth. The mineralization of the dental hard tissues in embedded teeth thus displays heavy disturbances especially in the fissures and the D.E.J.

ISSN:0001-6357    

DOI:10.3109/00016357409002528

出版商:Taylor&Francis    

年代:1974

数据来源: Taylor

摘要:

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 epithelium is prematurely reduced and the enamel stroma imbibed with hematic material.

ISSN:0001-6357    

DOI:10.3109/00016357409002529

出版商:Taylor&Francis    

年代:1974

数据来源: Taylor

摘要:

The sensitivity of experimentally exposed dentin, where the conditions at the outer tubule apertures were changed by various treatments, was studied in 40 contralateral pairs of teeth by intra-pair comparison. The results showed: (1) Dentin areas exposed by fracture were more sensitive than wet-ground dentin surfaces to application of dry, absorbent paper, scraping with a probe and a short blast of air. (2) Ground dentin surfaces treated for 2 minutes with 50% citric acid were more sensitive to the above mentioned stimuli and to application of a hyperosmotic solution (4-M CaCl2) than were untreated ground surfaces. (3) The sensitivity of ground dentin surfaces was markedly reduced by dehydration by a jet of air for 1 minute. The sensitivity rose after rehydration of the dehydrated surfaces by rubbing with water or gentle wet grinding. It is concluded that mechanical and dehydrating pain-producing stimuli are more readily transmitted from a dentin surface when the exposed tubule apertures are wide open, and the tubule contents are thereby easily accessible. This is the case in fractured and acid-treated surfaces, while following grinding and dehydration the apertures are blocked, and this results in a less sensitive surface.

ISSN:0001-6357    

DOI:10.3109/00016357409002530

出版商:Taylor&Francis    

年代:1974

数据来源: Taylor

摘要:

The position of the bolus in persons with mandibular prognathism was examined using a cineradiographic method before and after surgical correction of the prognathism. The pre-operative study included 30 persons, 18 women and 12 men. The test foods were bread and toffee. The results showed that the upper incisal region participated more and the premolar and molar regions less frequently in the chewing act than in other patient groups examined earlier with the same method. This was especially the case in persons with pronounced mandibular prognathism. It was concluded that these patients may have a poor masticatory ability.The post-operative registration was carried out on 23 of the patients. The results showed a more«normal»chewing pattern with a higher participation of the molar region. Due to this change the possibilities for a good masticatory function was considered increased after operation, but whether the chewing efficiency was improved could not be decided from the present study.

ISSN:0001-6357    

DOI:10.3109/00016357409002531

出版商:Taylor&Francis    

年代:1974

数据来源: Taylor

摘要:

Extra-cellular neutrophil collagenase and elastase were demonstrated by immunochemical methods in crevicular material from clinically healthy and chronically inflamed human gingivae. Collagenolytic activity was shown by viscosimetry and elastolysis by its digestive action on elastin agarose plates. Also the serum protease inhibitors,a,1-antitrypsin anda2-macroglobulin, were demonstrated in the crevicular material. The inflamed gingivae contained increased amounts of enzymes and inhibitors. The protease inhibiting capacity ofa1-antitrypsin was saturated in material from inflamed as well as from healthy gingivae, but free neutrophil collagenase and elastase were found mainly in crevices of the inflamed gingivae. It was suggested that free activities of these two proteolytic enzymes might contribute to collagen break-down in gingivitis and periodontitis.

ISSN:0001-6357    

DOI:10.3109/00016357409002532

出版商:Taylor&Francis    

年代:1974

数据来源: Taylor

摘要:

Penetration of bacteria into the tubules of intact dentin exposed by fracture was comparedin vitroin pairs of teeth, one of which in each pair was mounted with an intrapulpal hydrostatic pressure equivalent to 30 mm Hg. The teeth were incubated at 37°C for 21 days. Intra-pair comparisonsin vivowere made of bacterial invasion into dentinal tubules beneath ground dentin surfaces and beneath fractured or acid-treated surfaces, which were exposed for 1 week. It was found that an outward fluid flow in the dentinal tubules due to intrapulpal pressure may mechanically hinder bacterial growth into the tubules. Of greater importance as an obstruction to bacterial invasion was the blocking of the outer apertures of the dentinal tubules by grinding debris. This barrier, however, seemed to be removed after some days and this would allow bacterial ingrowth into intact vital dentin. It is concluded that dentinal surfaces that have been left unprotected and are covered with plaque for some days should be treated as carious dentin, and the surface layer should be ground off to remove widened apertures filled with bacteria.

ISSN:0001-6357    

DOI:10.3109/00016357409002533

出版商:Taylor&Francis    

年代:1974

数据来源: Taylor

摘要:

In the resting position and in persons with normal jaw relations the lips have a mutual surface of contact. Clinically, the area of contact constitutes a well-defined zone. This contact zone was made visible by smearing with ointment and measured in 24 young and 21 older persons. In all subjects the contact zone was band-shaped. Its widest dimension occurred laterally, narrowing medially. In the corner of the mouth it measured approx. 7.0 mm on an average, and in the median plane approx. 3.5 mm. A comparison was made of the changes that occur in the pars intermedia and the contact zone with advancing age. In the older subjects a significant reduction was recorded in the width of the pars intermedia (approx. 40 %). The dimensions of the contact zone on the other hand altered only slightly with age. The function of the contact zone is probably to seal the oral fissure when the mouth is closed. Surface contact between the two lips ensures effective adhesion.

ISSN:0001-6357    

DOI:10.3109/00016357409002534

出版商:Taylor&Francis    

年代:1974

数据来源: Taylor

ISSN:0001-6357    

DOI:10.3109/00016357409002535

出版商:Taylor&Francis    

年代:1974

数据来源: Taylor