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La monografía "Alteraciones Gingivo-Periodontales en niños y adolescentes", es resultado de la recopilación y análisis del material bibliográfico que en las últimas décadas se ha producido en relación al problema en los países anglosajones y habla hispana. La información recolectada se sistematiza partiendo de consideraciones generales en relación al tejido gingivo-periodontal sano para abordar así, el estudio de sus alteraciones en la niñez y adolescencia; enfatizando el papel de la placa bacteriana como factor etiológico fundamental o ligado a condicines sistémicas genéticas o adquiridas que debilitan la capacidad de resistencia del individuo y hacen vulnerable el tejido gingivo-periodontal a la acción destructiva de la microflora existente en la cavidad bucal. Estas alteraciones se engloban en el estudio bajo la denominación "cambios gingivo-periodontales por factores locales y predisponentes específicos", destacandose la etiología, evolución, patogenia e histología de la gingivitis, periodontitis y otras manifestacions periodontales asociadas con infecciones y alteraciones sanguíneas del sistema eritrocitario plaquetario y leucocitario. Por último, se hace referencia a los cambios gingivo-periodontales en pacientes con hábitos bucales y alteracioes físicas, mentales y de comunicación

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Human buccal mucosa fibroblasts and periodontal ligament cells grown in tissue culture were subjected to tensile forces approximating those used for orthodontic bodily tooth movement. The cells were synchronized into pre S phase and positively tested for response to nonmechanical physical stimuli. Two-dimensional gel analysis and immunohistochemical analysis of the three cytoskeletal components showed a lack of response. Similar negative results were found when the cells were perturbed in the presence of substance P. We hypothesize that perhaps these cells respond more readily to injury, a secondary effect of the forces of tooth movement, than to tensile forces.

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A topographical biochemical analysis of the periodontal soft tissues was carried out. The protein distribution in the tooth-supporting structures was determined from site by amino acid analysis and was compared with the collagen distribution in tissue protein, based upon hydroxyproline content. The biochemical composition of the periodontal ligament was heterogeneous but some specific patterns of protein and collagen distribution emerged. Protein concentration was highest at the gingival epithelium and adjacent to the cementum. Collagen concentrations were highest at the alveolar bone and below the junctional epithelium adjacent to the tooth. Such patterns may influence the way in which periodontal disease is propagated through the tissue.

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Mouse iodinated epidermal growth factor (EGF) was localized by light and electron microscopic radioautography in basal cells of oral epithelium, papillary cells of the enamel organ, periodontal ligament fibroblasts, preodontoblast precursor cells, and preosteoblasts of the alveolar bone of 13-day-old Sprague-Dawley rats. The specificity of binding in these cells was suggested by an observed reduction of about 90% in the labeling when excess unlabeled EGF was injected along with the 125I-EGF. In contrast, fully differentiated cells, such as ameloblasts, odontoblasts, and osteoblasts, were only poorly labeled. Quantitative analysis of the light microscopic radioautographs revealed that the papillary cells had the highest level of labeling (5.5 grains per 100 micron 2 of cell area). The significance of the rather high labeling of the preosteoblasts of the alveolar bone and the fibroblasts of the periodontal ligament is unknown. However, the well-known effect of EGF in producing precocious eruption of teeth may be a consequence of an effect on these two cell types.

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A 10 kDa collagenous peptide, derived from a 30 kDa disulfide bonded fragment, was purified from bovine periodontal ligament. Amino acid sequence analysis of tryptic peptides demonstrated a 92.8% homology with the chicken alpha 1(XII) cDNA derived sequence, demonstrating for the first time the presence of type XII collagen in a mammalian species and in an adult tissue.

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Using immunocytochemistry and a panel of monoclonal antibodies directed against various keratin polypeptides we examined specimens of normal periodontal ligament, periapical granulomas and inflammatory dental cysts. Epithelial elements with the appearance of rests of Malassez were identified in 6 specimens of normal periodontium and 10 periapical granulomas. Altered epithelium was present in 16 periapical granulomas and a lining epithelium in 10 inflammatory dental cysts. The patterns of binding of antibodies by these epithelia indicated that (a) keratin 19 was expressed by all epithelia, and (b) rests of Malassez also expressed keratin 5 but not large amounts of other keratins and (c) epithelial proliferation in periapical lesions was associated with increased expression of keratin 14, a marker of stratifying epithelia, new expression of keratins 4 and 13, differentiation markers for non-cornifying epithelia and variable, low levels of keratins 8 and 18, markers of simple epithelia. Proliferation of the epithelial rests of Malassez to form the lining of inflammatory dental cysts thus appears to be associated with a change from an unusual epithelial phenotype to that of a stratified non-cornifying epithelium in which some simple epithelial keratins are coexpressed.

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Several connective tissues were stained for proteoglycans using the cationic dye Cuprolinic Blue according to the critical electrolyte concentration method. With this method, proteoglycans are visualized as electron-dense filaments. In most tissues, two types of proteoglycan filaments are present: a small (maximum length 60 nm), thin, collagen fibril-associated filament, and a thick, heavily-staining filament which is predominantly localized between bundles of collagen fibrils. Cartilage contains very large (about 300 nm) proteoglycan filaments while in cornea they are very small. Comparison with biochemical data from the literature suggests that the appearance of the proteoglycan filaments may be indicative for the glycosaminoglycan-protein ratio and for the molecular weight of the part of the protein core to which glycosaminoglycans are attached. The data thus obtained on the localization and structure of a proteoglycan may be useful when planning a strategy for its isolation.

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Limited pepsin digestion of bovine periodontal ligament releases genetic types I, III, and V collagen and a high cystine containing low molecular weight collagenous component. Salt fractionation and molecular sieve chromatography allowed the isolation of the latter as an apparently pure homogeneous moiety which had an approximate molecular mass of 30 000 daltons. Reduction with mercaptoethanol yielded a single 10 000-dalton band on polyacrylamide gel electrophoresis in sodium dodecyl sulfate. This led us to conclude that the newly isolated low molecular weight collagen fragment consists of three similar molecular weight chains. Unreduced collagen-like glycoprotein (CGP) [Jander, R., Troyer, D., & Rauterberg, J. (1984) Biochemistry 23, 3675-3681] after extraction from tissues with collagen denaturing solvents yields the GP140 glycoprotein upon reduction and does not release any collagen fragment below 90 000 daltons upon mild or vigorous pepsin digestion. The GP140 glycoprotein [Heller-Harrison, R. A., & Carter, W. G. (1984) J. Biol. Chem. 259, 6858-6864] isolated by extraction under reducing and collagen denaturing solvent conditions did not yield a collagen fragment below 40 000 daltons after pepsin treatment. It was clearly shown that both CGP and GP140 yield type VI collagen fragments in the above-cited reports. Since this report demonstrates that the Mr 30 000 collagen fragment is only released by pepsin treatment of nondenaturing solvent treated periodontal ligament and that only very small peptides are found in denaturing solvent treated tissue after pepsin digestion, it is concluded that the newly isolated Mr 30 000 collagen fragment reported here is not derived from type VI collagen.(ABSTRACT TRUNCATED AT 250 WORDS)

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Fullmer's oxytalan fibers appear to be special connective tissue fibers belonging to elastic system fibers. We have ultrastructurally examined carbohydrates in oxytalan fibers in monkey periodontal ligaments after glutaraldehyde fixation and ethylenediaminetetraacetic acid (EDTA) decalcification using: Thiéry's periodic acid-thiocarbohydrazide-silver proteinate (PA-TCH-SP) method for thin-section staining of vicinal glycol-containing complex carbohydrates, and the concanavalin A-ferritin (Con A-ferritin) and Con A-horseradish peroxidase (Con-A-HRP) en bloc staining methods specific for alpha-D-mannosyl and alpha-D-glucosyl groups. PA-TCH-SP stained collagen fibrils weakly to moderately and stained oxytalan fibers moderately. Con A-ferritin and Con A-HRP stained collagen fibrils weakly or moderately and stained oxytalan fibers intensely within the superficial region of specimen blocks. The penetration of staining reagents was improved by prior saponin treatment and/or chondroitinase ABC digestion. Thus, these studies demonstrate that PA-TCH-SP and Con A staining of carbohydrates is very useful in identifying oxytalan fibers at the ultrastructural level and that more carbohydrate components are present in oxytalan fibers than in collagen fibrils.

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Fibrinogen and IgG were demonstrated in the hyaline zone with direct immunofluorescent staining after orthodontic tooth movement in man. It was suggested that presence of plasma proteins in the hyaline zone contributed to its hyaline appearance. Fibrin and IgG may, furthermore, attract phagocytes and form a network for the reorganization of the necrotic tissue in the hyaline zone.

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A quantitative gas-liquid chromatographic method has been developed for the simultaneous determination of the several monosaccharides present in glycosaminoglycans from animal tissues. In order to achieve a high degree of depolymerization of the glycosaminoglycans, it was found necessary to make them more susceptible to methanolysis by re-N-acetylation during the methanolysis procedure. Good resolution of all common monosaccharides, such as pertrimethylsilyl methyl glycosides, was achieved by the use of a capillary column of fused silica with the liquid phase CPtm leads to Sil 5. The method described was tested on glycosaminoglycans isolated from bovine periodontal ligament and the sensitivity (down to 3 micrograms monosaccharide) makes this method useful in the analysis of small amounts of soft connective tissues with low glycosaminoglycan contents.

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Collagen fibril diameters were measured in electron micrographs of rat skin, gingiva and periodontal ligament. Gingiva was divided into two zones, termed elastin-containing gingiva and attached gingiva, depending on the presence or absence of elastic fibrils. The results revealed that skin had the largest fibrils, followed by elastin-containing gingiva, attached gingiva and periodontal ligament respectively. These differences in fibril diameter were highly significant. The observed trend in fibril diameter was the inverse of that documented for collagen turnover and collagen phagocytosis in the same tissues. A link between fibril diameter and collagen turnover is discussed.

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A proteoglycan purified from 4 M-guanidinium chloride extracts of bovine periodontal ligament closely resembled that of bovine skin, except for a rather lower protein content and a higher molecular weight (120 000 compared with about 90 000) by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. The latter difference was explained by the molecular weights (29 000 and 16 000) of the respective dermatan sulphate components, each of which was rich in L-iduronate (about 75% of the total hexuronate). Significant amounts of other glycosaminoglycans did not occur in these proteoglycans, which were homogenous on gel chromatography and agarose/polyacrylamide-gel electrophoresis. Polydispersity was observed in sedimentation equilibrium experiments, but proteolysis or self-association of the proteodermatan sulphates may have affected these results. Ligament proteoglycans that were almost completely extracted with 0.1 M-NaCl contained less protein of a completely different amino acid composition than the proteodermatan sulphates. They were heterogeneous in size but generally smaller than cartilage proteoglycans and L-iduronate was a component, comprising about 7% of the total hexuronate of the sulphated galactosaminoglycan chains. The latter consisted of two fractions differing in molecular weight, but a dermatan sulphate with a high L-iduronate content was not present. These proteoglycans had some resemblance to D-glucuronate-rich proteoglycans of other non-cartilaginous tissues. Such compounds, however, are difficult to categorize at present.

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Sulfated galactosaminoglycans of mature bovine periodontal ligament were separated into four fractions by ethanol precipitation. Fractions I and II were dermatan sulfates with high contents of L-iduronate, but only small amounts of this hexuronic acid were present in fractions III and IV. Effects of digestion with testicular hyaluronidase or a periodate-alkali treatment showed that most if not all of the glycans in fractions I, II and III were hybrid chains containing both L-iduronate and D-glucuronate. The composition of fraction IV was less certain, but the chains strongly resembled fraction III hybrids in electrophoretic characteristics, not chondroitin sulfate. The total amount of the D-glucuronate-rich fractions III and IV in the ligament was similar to that of I plus II. In contrast, almost all of the sulfated galactosaminoglycans of mature skin were rich in L-iduronate. The more varied composition of the ligament glycosaminoglycans may be related to the mixed population of cells in this tissue.

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Mature mouse mandibular third molars together with their periodontal ligaments and alveolar bone were isografted to two heterotopic sites: the renal subcapsular site and the tibial shaft medulla. The pulps and periodontal ligaments of the grafts underwent cellular degeneration after transplantation but demonstrated signs of revascularization and cellular repopulation 7 days after transplantation. Grafts obtained at 28, 60 and 100 days after transplantation demonstrated a significant decrease in the width of the periodontal ligament, a decrease in the number and organization of mature periodontal fibre bundles, the appearance of fibers arranged parallel with the root surface and a decrease in the thickness of surrounding alveolar bone. These regressive changes in the periodontal ligament were considered to be due primarily to the nonfunctional status of the teeth at the two heterotopic sites.

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