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Biomedical subjects

B Kerebel

Publications and source records attributed to B Kerebel.

At least 19 recordsLinked to original sources
PubMed1992

Histologic case reports of coralline hydroxyapatite grafts placed in human intraosseous lesions: results 6 to 36 months postimplantation.

Four intrabony lesions from four patients were studied. Presurgical measurements included clinical attachment level, degree of recession, probing pocket depth, Plaque Index, Gingival Index, and Sulcular Bleeding Index. These measurements were also taken at 6-month intervals after surgery. Surgery involved exposing the intrabony defects by a papillary preservation technique, planing, and placing blocks of coralline hydroxyapatite. Three biopsy specimens and one block section were removed from the treated lesions at various periods ranging from 6 to 36 months. Clinical and histologic observation provided evidence of osteogenesis around and through the coralline hydroxyapatite.

Adult↗
PubMed1991

Scanning electron microscopic study of odontoblasts and circumpulpal dentin in a human tooth.

Two combined scanning electron microscopic methods including modified fixative procedures were used for studying the morphologic aspects of the odontoblasts and the corresponding dentinal wall at different endodontic levels. The odontoblasts were tightly packed in the pulp horn, where they assumed pear-shaped profiles and, from crown to apex, successively looked spindle shaped, club shaped, and globular. Their number decreased in the pulp radicular portion, where the interglobular spaces were enlarged. The filling fibrillar material varied from crown to apex. A globular circumpulpal dentin was observed at all levels of the root canal. The tubule openings varied in number and size.

Adult↗
PubMed1991

[A clinical and histological study of the efficacy of betadine on gingival inflammation].

12 patients (7 men and 5 women) with advanced periodontitis and probing depths of 4mm or more were selected to assess the effectiveness of an antiseptic: betadine used in situ, as a subgingival irrigation in periodontal pockets. Although widely used in other fields of medicine such as gynecology and dermatology, betadine has not been used in periodontology. However, betadine is an excellent antiseptic with a wide range of action. The slow release of iodine explains why this antiseptic is well tolerated by mucosae. The oral cavity was divided in 2 parts: the left side was irrigated with betadine while the right side was irrigated with saline which was used as a control. Irrigations were performed once a day during a period of 15 days. Patients were able to carry out the irrigations themselves after careful, instruction. Thc practitioner carried out the irrigation on day 0 and day 8. The comparison of clinical and histological data showed a decrease in gingival inflammation after 15 days of treatment. By means of the Student "t" test significant decreases in the plaque index, the gingival, index and the bleeding index were observed between day 0 and day 15 as well as a significant increase in recession. These clinical results were correlated with histological findings. Significant decreases in the volumetric density of the infiltrated connective tissue, the non collagenous structures and the number of plasma cells were observed as well as significant increases in the volumetric density of the non-infiltrated connective tissue of the collagenous structures and the number of fibroblasts.

Administration, Topical↗
PubMed1991

[Clinical and histological evaluation of implantation of a microporous resin in periodontitis. Report of a case after 13 months].

A patient with adult periodontitis was treated for a 2 and 3-walled intrabony lesion on tooth n degrees 27. After scaling and root planing, the defect was surgically exposed and filled with a micro-porous resin. Following healing, there was a reduction in pocket depth as a result of gingival recession and a gain in probing attachment levels. This was confirmed 13 months post-operatively by clinical observation on re-entry. A biopsy of the treated site was taken at that time and undecalcified sections were studied by light microscopy and microradiography. New bone formation was noted inside and on the surface of the resin granules and at a distance from the particles. From a clinical and histologic point of view, the material seemed to be well tolerated by the host.

Adult↗
PubMed1989

Transformation of biphasic calcium phosphate ceramics in vivo: ultrastructural and physicochemical characterization.

Specially prepared biphasic calcium phosphate (BCP) macroporous ceramics consisting of an intimate association of beta tricalcium phosphate (beta-TCP) and hydroxyapatite (HA) with beta-TCP/HA weight ratios of 15/85, 35/65, and 85/15 were implanted in surgically created periodontal osseous defects in dogs and recovered after 6 months. A decrease in average size of crystals in BCP ceramics and an increase in the size of microporosities in the surface and at the core of the ceramic after implantation were observed, indicating that in vivo dissolution has taken place. The resorbability (reflecting in vivo dissolution) of BCP ceramics depended on their beta-TCP/HA ratios, the higher the ratio, the greater the resorbability. The formation of microcrystals with crystallographic properties and Ca/P ratio similar to those of bone apatite crystals were also observed. The abundance of these crystals were directly related to the beta-TCP/HA ratio of the BCP ceramic before implantation. The formation of the bone apatite-like crystals may be due to the precipitation of calcium and phosphate ions released from the dissolving ceramic crystals (the beta-TCP component dissolving preferentially to the HA component). Results from this study suggested that one of the means of controlling resorbability (in vivo dissolution) of BCP ceramic is by varying its beta-TCP/HA ratio.

Animals↗
PubMed1989

Chemical changes in hydroxyapatite biomaterial under in vivo and in vitro biological conditions.

The introduction of a synthetic calcium phosphate into a biological environment is likely to result in surface-mediated chemical events. On the basis of such an assessment, we studied the chemical changes occurring in the mineral after exposure of a synthetic hydroxyapatite ceramic to both in vivo (implantation in human) and in vitro (cell culture) conditions. A small amount of the material was phagocytized but the major remaining part behaved as a secondary nucleator as evidenced by the appearance of a newly formed mineral. Morphologically, the newly formed mineral appeared as tiny crystals precipitated and grown from the surface of the initial synthetic crystals. The density of the additional mineral increased from the periphery to the core of each biomaterial aggregate. Chemically, it was identified by IR spectroscopy as a carbonated apatitic mineral. We propose that the adsorption of biomolecules could inhibit precipitation, accounting for the increasing amount of precipitate from the periphery to the core of the aggregates.

Adult↗
PubMed1989

A transmission electron microscope study of fibroblast changes in human deciduous tooth pulp.

The coronal pulps of four primary canines, free from radicular resorption, and of three primary teeth, with roots entirely resorbed, were prepared for electron microscopy. Mature fibroblasts, similar to those reported in the pulps of permanent teeth, were present in the pulps of the clinically mature teeth. Regression of fibroblasts, evident in the pulps of deciduous teeth at the root resorption stage, was characterized by cytoplasmic changes, modifications in the cytoskeleton and dissociation of cells and fibrils. Deciduous teeth might provide a model for studying pulp fibroblast ageing.

Actin Cytoskeleton↗
PubMed1989

Regional odontodysplasia: new histopathological data.

Light microscopy, microradiography, SEM and TEM of 4 tooth follicles in a 12-year-old caucasian girl presenting regional odontodysplasia showed widespread globular dentin, calcifications located in the enlarged pulp chambers, hypoplastic and hypomineralized enamel. Hypomineralized strands were sandwiched between two normal enamel layers, which indicates that amelogenesis, interrupted for a while, has once more become established. The enamel surface was covered with calcoglobules. Numerous rounded calcifications were scattered within the dental follicles. Some of these occurred in microfibrils (possibly oxytalan fibers), distinct from collagen fibers. Calcification of the sheath surrounding epithelial rests was a conspicuous feature. The fibroblasts in contact with calcifications developed numerous cytoplasmic extensions, which suggests that they may have assumed a phagocytosis behaviour.

Child↗
PubMed1989

Comparison of the dental health status of 8 to 14-year-old children in France and in Jordan, a country of endemic fluorosis.

In the present paper, data obtained from a survey dealing with dental carie, dental fluorosis and gingival health, involving 2618 Jordanian schoolchildren, aged 8 to 14, were compared with data from another survey dealing with 1058 schoolchildren of the same age groups living in a non-fluoridated area in the west of France. As regards dental carie in temporary teeth, up to the age of 12, the dft and dfs scores were higher in France than in Jordan. Over the age of 12, the difference was no longer significant. As regards dental carie in permanent teeth, the data showing that Jordanian children are less subject to caries than the French were very highly significant. Also, it was shown that caries index in girls was higher than in boys. These data were not significant in the French survey, but highly significant in the Jordanian investigation. A possible explanation is that, due to the custom of the country, boys in Jordan drink much more tea (with high fluoride content) than girls. As regards gingival health, an interesting finding was that, compared to the French children, the percentage of Jordanian children presenting gingivitis is remarkably low. The fluoride content of the dental plaque might play a restricting and preventing role.

Adolescent↗
PubMed1989

[Anomalies of enamel formation in subjects with maxillary clefts].

A structural and ultrastructural study of teeth located in the vicinity of maxillary cleft and teeth located outside the cleft region, was made in 12 cases, using correlated light microscopy, microradiography and SEM. All teeth directly involved in cleft process presented gross hypoplasia of the crown where the enamel surface was hypomineralized. Globular calcified masses of different radiodensity were seen on the hypomineralized enamel surface. The teeth located outside the cleft region presented less pronounced anomalies constituted by isolated or group microhypoplasia on hypomineralized enamel. The observation of enamel pearl was not pathognomonic of maxillary cleft.

Cleft Lip↗
PubMed1989

[Comparative study of bioactive calcium phosphate ceramics after implantation in spongy bone in dogs. Histologic, ultrastructural and electron probe microanalysis].

An experimental model of posterior spine arthrodesis in dogs was created using 3 types of calcium phosphate biomaterials already known for their applications as bone substitutes, namely: hydroxyapatite (HA), which is not readily resorbable; highly resorbable tricalcium phosphate (TCP); and a mixture of HA and TCP (BCP), the resorbability of which depends on the proportion of HA and TCP. The BCP implants had a macroporous structure, whilst the HA and TCP implants were used in dense form. The creation of macropores increases the surface exchange area, thus enabling the osseous colonization processes. By carefully removing the posterior articular facets it was possible to remove the articular surfaces and to fit into each appropriate location a block a few millimeters in diameter. The anatomopathological assessment was performed using histological methods, transmission electron microscopy, and energy dispersion microprobe analysis. Our results indicate that calcium phosphate ceramics may be used as bone substitutes for carrying out arthrodeses, provided (1) immediate immobilization using a spine containment technique is effected; (2) their chemical composition is sufficiently stable over time; (3) they are sufficiently bioactive so as to allow their colonization and replacement by bone.

Animals↗
PubMed1989

[Osteogenesis imperfecta and dentinogenesis imperfecta. Apropos of 4 cases].

Based on four personal cases of osteogenesis imperfecta and dentinogenesis imperfecta, the authors review the semiological elements constituting the syndrome, and assign each case to the Sillence (1979) classification. The author established his classification on clinical criteria and the genetic nature of the various forms of osteogenesis imperfecta, however, the most recent discoveries concerning collagen biochemistry confirm that the condition is without doubt more heterogenous than suggested clinically, thereby better explaining the wide range of mutations encountered.

Child↗
PubMed1989

Hydroxyapatite biomaterial implanted in human periodontal defects: an histological and ultrastructural study.

The purpose of the present work was to study the response of human periodontium to hydroxyapatite biomaterial particles (180-200 microns). The biomaterial was implanted in two infra-osseous periodontal defects (two patients) after clearing of the granulation tissue. At two months post-surgery, biopsies were studied using light and electron microscopy. No sign of inflammation was observed, the biomaterial aggregates were surrounded either by typical fibroblasts or larger phagocytotic cells with phagocytosis vesicles containing biomaterial crystals. These intracellular crystals were noticeably smaller than the non-phagocytized ones. Some of the phagocytized crystals showed morphological signs of intracellular dissolution. The spaces between the crystals constitutive of the aggregates were filled with organic substance containing collagen fibers.

Biopsy↗
PubMed1989

Treatment of a periodontal intrabony pocket in man by a mucoperiosteal free graft combined with a calcium phosphate implant.

A two-walled intrabony pocket was treated by a mucoperiosteal free graft interposed between the curetted root surface and a calcium phosphate implant. The eighteen months follow up radiography showed complete healing of the bone defect, a normal periodontal ligament space, an uninterrupted lamina dura and a well-formed septum. The use of mucoperiosteal free graft may supply the wounded area with different cells such as fibroblasts, undifferentiated mesenchymal cells, periosteal cells, intercellular fibers and biochemical substances such as glucosaminoglycans, proteoglycans etc...

Adult↗
PubMed1989

Structural and ultrastructural study of the teeth in a suspected case of pseudohypoparathyroidism.

Two premolars removed from a 14 year old girl, with suspicion of pseudohypoparathyroidism (PHP) have been studied, using several of the correlated techniques applied to the study of calcified tissues (light microscopy, microradiography and scanning electron microscopy). Enamel gross and micro hypoplasia, hypomineralization of the enamel surface and dentin hypocalcification were similar to dental abnormalities observed in pseudohypoparathyroidism. Microradiography showed for the first time calcifications present in blood vessels of the dental pulp. Light microscopy and SEM revealed dystrophic globular calcifications within enamel hypoplastic pits. Cemental changes consisting of hypoplasia, aplasia, localized hyperplasia and cementicules were described for the first time. It is suggested that enamel, dentine and pulp abnormalities observed in the present case might be pathognomonic of PHP.

Adolescent↗
PubMed1989

[The role of tea consumption in dental fluorosis in Jordan].

2,516 children of both sexes, six to fourteen years old, were examined in Jordan in the course of an epidemiological study. 81.11% of girls and 76.43% of boys presented severe forms of dental fluorosis according to DEAN's index. Drinking water analysis revealed fluoride concentrations ranging from 0.27 to 1.4 mg F/l. These concentrations are neighbouring optimum tolerated fluoride supplementation in drinking water. However high annual temperature mean and ten hours daily sunshine must also be taken in consideration. For social and climatic reasons, Jordanian children drink daily high quantities of tea. Analysis of tea prepared on jordanian way revealed a concentration of 1.2 mg F/l. This continuous intake of fluoride might explain the high severity of dental fluorosis in Jordan.

Adolescent↗
PubMed1989

[Structural, ultrastructural and microanalytical study of multiple enamel pearls].

Numerous enamel drops and compound enamel pearls were found on the radicular proximal faces of maxillary molars and mandibular third molars of a young woman. Enamel and dentin of compound pearls as well as cementum next to drops and pearls presented the same structure and ultrastructure as enamel, dentin and cementum of the corresponding teeth. Microanalysis did not reveal differences between enamel of the mother tooth and enamel of drops and pearls. The enamel drops had no incremental growth lines. Cementum next to enamel drops and compound enamel pearls was acellular and covered occasionally with a thick layer of cellular cementum. Only enamel drops were partially covered by acellular cementum. Close to the enamel drops and at their surface, numerous fusing globular calcifications were observed. Formation of enamel drops and compound enamel pearls on dental root surfaces is rare. The simultaneous presence of numerous enamel drops and some compound enamel pearls on several roots of molars in the same denture seems to be an exceptional phenomenon. The involved factors inducing enamel formation remain still unknown. The multitude of both enamel drops and compound enamel pearl might be due to constitutional predisposition.

Adult↗