Blood group substances as differentiation markers in human dento-gingival epithelium

The level of cellular differentiation of human oral, sulcular, and junctional epithelium was compared by immunohistochemical analysis of cell membrane-associated blood group-specific carbohydrates. Identification of the blood group A-specific carbohydrate and its two immediate precursor substances, type 2 chain H and N-acetyllactosamine, was accomplished by an indirect immunofluorescence technique. Murine monoclonal antibodies reacting specifically with the antigenic determinants of the blood group substances were used as markers. The blood group A substance, indicating the highest level of cellular differentiation, was demonstrated on the cells in the upper layers of the oral epithelium. In the sulcular epithelium, the A substance was present on a few cells only, while type 2 chain H was observed frequently. This indicates an intermediate differentiation level of sulcular epithelium. The type 2 chain H precursor, N-acetyllactosamine, the indicator of the lowest level of cell differentiation among the tested substances, was the only blood group substance detected on the junctional epithelial cells and on the basal cells of the sulcular and oral epithelium. Based upon previous studies of cell renewal and differentiation in oral epithelium, the present results indicate that the variations in distribution of the different blood group substances correspond with the regional rates of cell division and the levels of cellular differentiation. The findings also suggest that the cells in the junctional epithelium differentiate to a level similar to that of basal cells in the oral epithelium.     

Use of systemic fluoride supplements by North Carolina dentists

This 1984 survey focuses on the use of systemic fluoride supplements by North Carolina dentists. Respondents included all the state's pediatric dentists and general practitioners who assay water supplies before prescribing fluoride supplements, and other randomly selected general practitioners who treat children. Whether practicing in fluoridated or nonfluoridated communities, most dentists prescribed systemic fluoride supplements but only a small number of practitioners assayed water supplies before doing so.     

In situ characterization of mononuclear cells in human chronic marginal periodontitis using monoclonal antibodies

Acetone fixed cryostat sections from 25 patients with adult chronic marginal periodontitis were characterized using an indirect immunofluorescence technique with monoclonal antibodies. The amount of B lymphocytes (Leu-12 positive) varied considerably between the specimens and were usually seen in largest numbers in the most apical parts of the cellular infiltrates beneath the pocket epithelium (PE). Varying amounts of T lymphocytes (OKT 3 positive) were demonstrated in all specimens. The amount of T helper cells (OKT 4a positive) exceeded that of T suppressor/cytotoxic cells (OKT 8 positive) in the cellular infiltrates beneath the PE (OKT 4a/ OKT 8 =1.13). There was a more even distribution of these cell types beneath the oral gingival epithelium (OGE). Langerhans cells were observed within and occasionally subjacent to the OGE. Scattered macrophages (Leu-M3 or OK Ia 1 positive) were observed in the inflammatory cell infiltrates and on the connective tissue papillae beneath the OGE. HLA-DR antigen reacting with OK Ia 1 was present on cells corresponding to OKT 6 positive cells in the OGE and subjacent to the OGE as well as in the inflammatory cell infiltrates beneath the PE and in the perivascular infiltrates. In some specimens HLA-DR antigen was also found to be associated with keratinocytes in the outer parts of the OGE. Occasional NK cells (Leu-7 positive) were localized inside and subjacent to the OGE. There was a considerable variation with respect to the number and distribution of the various mononuclear cells between specimens and from section to section from the same specimen.     

Frontzahnstellung und Weichteilprofil—eine experimentelle Studie

Zusammenfassung Zahnlose Patienten mit noch guten Kieferverh?ltnissen, bei denen eine Versorgung mit Totalprothesen durchgeführt worden war, dienten als Modell, um die Auswirkungen einer systematischen Variation der Frontzahnstellung auf das Weichteilprofil studieren zu k?nnen. Dafür wurden Durchzeichnungen von bei verschiedenen Frontzahnstellungen gewonnenen Fernr?ntgenseitenbildern überlagert und miteinander verglichen. Es zeigte sich, da? die Auswirkungen von verschiedenen Faktoren abh?ngen. Der bisher kaum berücksichtigte Faktor „vertikale Lagerelation” erwies sich dabei als besonders bedeutsam.

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Summary In order to study the effect of variation of the front teeth on the soft tissue profile, edentulous patients with good jaw relationships and fitted with dentures were taken as models. Radiographs were made with the front teeth in different positions and the tracings were superimposed and compared with one another. We saw that the effect depends on various factors. The factor “vertical position” proved particularly significant.

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Résumé Afin d'étudier les effets de la variation systématique de la position des incisives sur le profil cutané, nous avons pris comme modèle des patients édentés qui portaient une prothèse, mais dont les machoires étaient encore en bon état. Après avoir radiographié les patients avec les incisives en différentes positions, nous avons superposé les radiographies et nous les avons comparées. Nous avons vu que l'effet produit dépend de plusieurs facteurs. Le facteur ?position verticale? s'est révélé être particulièrement significatif.

     

Correlation of scanning and transmission electron microscopy of human dentinal tubules

Areas of human dentine were examined first with the scanning electron microscope (SEM) and subsequently with the transmission electron microscope (TEM). Structures observed in dentinal tubules from outer dentine by SEM were identified by TEM as electron-dense structures lining the tubules and not as odontoblast processes. These structures, termed lamina limitans, correspond to the previously described inner hypomineralized lining of dentinal tubules.