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Biomedical subjects

R M Frank

Publications and source records attributed to R M Frank.

At least 55 records · Page 3Linked to original sources
PubMed1989

[The orodental status of the French population 6-15 years of age].

A representative sample of 19,366 schoolchildren of France, aged 6 to 15 years, was randomly selected. Examiner teams from each of the 16 Faculties of Dental Surgery of France were trained together to be well calibrated. The dental caries prevalence was determined in each age group using the dft, dfs, DMFT and DMFS indices. The periodontal conditions were measured using the plaque index (Silness and Löe, 1964), the calculus index (Marthaler, 1966) and the gingival index (Löe and Silness, 1963). The mean DMFT index increased from 0.5 at age 6 to 6.9 at age 15 years. This index increased by 0.5 from one age group to the next until age 10, and from 1.0 from age 11 to age 15. The DMFS index increased from 0.8 to 13.0 between 6 and 15 years of age. In each age group, the numbers of carious and untreated surfaces were very similar to the number of filled surfaces. The percentage of children with caries-free permanent teeth decreased from 78.5% to 8.2% between 6 and 15 years of age. A direct relation was observed between the caries indices and the socio-economic category of the parents. The senior management and private professions presented the lowest indices.

Adolescent↗
PubMed1988

Transmission electron microscopy of the human odontoblast process in peripheral root dentine.

Various methods of fixation were tried on dentine of 45 premolars from children. Two methods based on immediate or delayed use of liquid nitrogen, as well as a cryoprotector (10 per cent dimethylsulphoxid), gave the best results in transmission electron microscopy. Using these methods, the presence of an odontoblast process could be demonstrated in the inner, middle and peripheral human root dentine. The presence of unmyelinated nerve fibril in outer root dentine supports the hypothesis of direct neural stimulation in peripheral dentine.

Adolescent↗
PubMed1988

Age-related lead increase in human permanent teeth demonstrated by energy dispersive X-ray fluorescence.

The combined use of a systematic sampling procedure with energy dispersive X-ray fluorescence on non-erupted and erupted permanent premolars and molars in patients aged 9 to 64 years, who have lived all their lives in Strasbourg, showed a higher total lead content in dentine compared to enamel, with an approximate ratio of 2:1. In addition, a lead increase was observed in both tissues with age. The lead increase in dentine was more significant and the highest lead values were noted in the inner pulpal dentine layer of the oldest age group. When compared to similar lead studies made on permanent teeth in urban areas, it can be concluded that the lead content in the teeth of the inhabitants of Strasbourg can be considered as low.

Adolescent↗
PubMed1988

A method of lead determination in human teeth by energy dispersive X-ray fluorescence (EDXRF).

A systematic sampling procedure was combined with a method of energy dispersive X-ray fluorescence (EDXRF) to study lead content and its variations in human teeth. On serial ground sections made on unembedded permanent teeth of inhabitants of Strasbourg with a special diamond rotating disk, 2 series of 500 microns large punch biopsies were made systematically in 5 directions from the tooth surface to the inner pulpal dentine with a micro-punching unit. In addition, pooled fragments of enamel and dentine were made for each tooth. On each punched fragment or pooled sample, lead content was determined after dissolution in ultrapure nitric acid, on a 4 microns thick polypropylene film, and irradiation with a Siemens EDXRF prototype with direct sample excitation by a high power X-ray tube with a molybdenum anode. Fluorescence was detected by a Si(Li) detector and calcium was used as an internal standard. This technique allowed a rapid, automatic, multielementary and non-destructive analysis of microsamples with good detection limits.

Biopsy↗
PubMed1988

Approximal caries diagnosis in epidemiological studies: transillumination or bitewing radiographs?

The aim of this study was to compare the results obtained by transillumination and bitewing radiography in the diagnosis of caries affecting approximal surfaces of molar and premolar teeth for epidemiological surveys. 3960 posterior approximal surfaces on the right side of 330 patients aged 5 to 35 years were examined using a transillumination probe with a 1.5 mm diameters light source (Oralum, Rocky Mountain, Denver, Colorado) and bitewing radiographs using a portable dental apparatus (Elin, Wien, 60kV, 15mA. Transillumination detected 89% of the carious lesions reaching dentine diagnosed on radiographs and no statistically significant differences were observed in the diagnosis yield of the two systems. However, transillumination detected only 45% of these lesions diagnosed from bitewings as being confined to the enamel. Transillumination also made it possible to detect approximal caries into dentine in teeth covered by orthodontic bands. Thus comparative study gives experimental support to the use of transillumination in large epidemiological studies. The transillumination method is however not suitable for epidemiological trials including caries confined to the enamel.

Adolescent↗
PubMed1988

[Evaluation of the Caridex system and its pulp biocompatibility].

A study of the pulpal biocompatibility of the Caridex system was carried out on human premolars to be extracted bilaterally for orthodontic reasons, in 3 volunteers aged 10 to 13 years. A class V cavity was prepared bilaterally on the 2 premolars to be extracted: one of the cavities was washed with Caridex. The other was used as a control. The extractions were made immediately, 4 and 7 weeks after these operative procedures. Histological examinations showed that the Caridex system was biocompatible for the human dental pulp. A comparative study of carious cavities was conducted using light microscopy, Gram stain and transmission electron microscopy on the quality of the cleaning obtained after conventional cavity preparation and use of the Caridex system. After Caridex treatment, the dentinal surface was free of demineralized zones and no smear layer was present. The occasional presence of bacteria was noticed after conventional use of a bur as well as after Caridex. More limited clinical indications of the Caridex system are proposed.

Adolescent↗
PubMed1988

[Epidemiological study of the oro-dental status of the children of the Alsace and the Franche-Comté].

Within a national epidemiological study conducted in France by the 16 Faculties of Dentistry, 946 school-children aged 6 to 15 years were randomly selected and examined in East of France. The Dental Faculty of Strasbourg studied the following departments: Doubs, Jura, Bas-Rhin, Haut-Rhin and Territoire de Belfort. Twenty per cent of the 12 year old children had a DMFT of 0, whereas by the age of 15 this percentage felt to 7%. The mean DMFT and DMFS of the 12 year old children were respectively of 4.6 and 8.7. The mean plaque index varied from 1.2 to 1.5 for all age groups. The mean calculus index increased progressively with age from 0.1 to 0.6. The mean gingival index was almost constant until the age of 8 (0.6 to 0.8). It reached 1.2 at 9 and remained unchanged until 15.

Adolescent↗
PubMed1987

Transmission electron microscopy of lattice planes in human alveolar bone apatite crystals.

Periodic fringes corresponding to six different lattice planes have been observed in apatite crystals of human normal alveolar bone by transmission electron microscopy. Three of these sets of fringes have spacings less than 3.5 A corresponding to the Scherzer resolution of the microscope used. The (0002) lattice plane of hydroxyapatite of 3.4 A d-spacings, the (2111) lattice plane with a d-spacing of 2.81 A, and the (3030) lattice plane with a d-spacing of 2.72 A have been identified. The (0002) and (2121) lattice planes have been observed for the first time in bone microcrystals. Some of the crystals studied were characterized by a mean width/thickness ratio of 6.91, typical of platelike habit, whereas observations of crystals aligned along the (1210) and (1211) directions showed a needlelike habit. The mean length of the bone apatite crystals was 470 A. A dark line similar to the one observed in enamel and dentine crystals was also seen. The bone microcrystals observed have shown a high sensitivity to beam damage.

Adolescent↗
PubMed1987

Local response in rat to liposome-associated Streptococcus mutans polysaccharide-protein conjugate.

The effect of gastric intubation with soluble or liposome-associated Streptococcus mutans serovar polysaccharide, 74-kDa saliva receptor (74K SR protein) or polysaccharide-74K SR protein conjugate on the locally induced salivary IgA response and memory in rats was investigated. Animals immunized on four successive days with soluble antigens showed a weak salivary anti-74K SR protein or anti-polysaccharide IgA response. Rats primed and boosted by a single injection of liposome-associated 74K SR protein or polysaccharide-74K SR protein conjugate developed a salivary anti-74K SR protein IgA and IgG primary and secondary response. A primary anti-polysaccharide response was only observed in saliva of animals immunized with either high concentration of liposome-associated polysaccharide or liposome-associated polysaccharide-74K SR protein conjugate. However, a secondary local anti-polysaccharide IgA response was detected in animals boosted with liposome-polysaccharide-74K SR protein conjugate. No such anamnestic response was seen when high dose of liposome-associated polysaccharide was used to boost the animals. Furthermore, the salivary anti-polysaccharide IgA response paralleled the anti-74K SR protein IgA response. These studies showed that intragastric immunization of rats with liposome-associated polysaccharide-74K SR protein conjugate produced a local anti-polysaccharide IgA memory.

Animals↗
PubMed1987

Comparative study of oral conditions in schoolchildren of Strasbourg, France, 1974-85.

A representative sample of 1650 children randomly selected in the 6-15-yr-old schoolchild population of Strasbourg was examined by well-calibrated examiners. The prevalence of caries was determined with the DMFT, DMFS and dft indices using bitewing radiographs. Plaque, calculus and gingival indices were also determined. The results obtained were compared with the initial study of 1974 performed in Strasbourg using the same epidemiologic methods. Whereas no important variations were observed in caries prevalence of primary teeth, a significant reduction of caries activity was observed in DMFT and DMFS indices in all age groups. There was a reduction of these two indices of respectively 32% and 33% in the 12-yr-old children. The reduction was the most significant on approximal surface lesions. A statistically significant decrease of the calculus and gingival indices was also observed between 1974 and 1984. A less significant decrease was observed for the plaque index.

Adolescent↗
PubMed1987

[Ultrastructural study of bone formation after bioapatite implantation in man].

Synthetic hydroxyapatite crystals (Bioapatite) were implanted in a vestibular longitudinal groove made in the alveolar bone, the periodontal membrane and the superficial root dentine of 2 human canines in the absence of periodontal disease. The healing process was followed in scanning as well as in transmission electron microscopy. At 6 months, the aggregate of synthetic hydroxyapatite crystals was surrounded by a fibrous connective tissue, devoid of inflammatory cells. Small apatite crystals, similar to the neighbouring bone crystals, were deposited between the Bioapatite crystals in the central area of the aggregates. These small crystals filled the intercrystalline spaces from the center to the periphery. The mineralization extended then directly in the collagen matrix (osteoid tissue) surrounding the synthetic apatite aggregates. Bone tissue was thus formed around the apatite implants. At 1 year, the thickness of the bone tissue formed around the synthetic hydroxyapatite aggregates was increased. It consisted of bone with a well-oriented collagen matrix, with osteocyte lacunae, osteocytes and interosteocytic canaliculi, with normal ultrastructure.

Alveolar Process↗
PubMed1987

Scanning electron microscopic search for peritubular dentine in some early perissodactyls.

A scanning electron microscopic study has shown the presence of a typical layer of peritubular dentine in Hyrachyus. An homogeneous ring-shaped layer in continuity with intertubular dentine and considered as peritubular dentine despite its acid resistant character was observed around the lumens of dentinal tubules in Protungulatum, Tetraclaenodon and Propachynolophus maldani teeth; there is some evidence that the acid solubility of peritubular dentine has been altered during fossilization. No peritubular dentine was found in Phenacodus, Hyracotherium or Homogalax.

Animals↗
PubMed1986

MAV-2-O replicates at a reduced rate in cells from the osteopetrosis resistant G-B1 chicken.

The replication of the avian osteopetrosis virus MAV-2-O was compared in chick embryo fibroblasts from two strains of chicken. These were G-B1 which is relatively resistant to MAV-2-O and CB which is susceptible. The production of MAV-2-O was delayed in G-B1 cells (compared with CB cells). The same result was observed after infection with Rous sarcoma viruses of subgroups B, C, and D. In addition, the transforming viruses induced foci on G-B1 fibroblasts 24 to 48 hours later than on CB fibroblasts. In G-B1 cells there was also a delayed kinetics of intracellular viral RNA production. Integrated and linear unintegrated MAV-2-O DNA species were also present in lower amounts in G-B1 than in CB fibroblasts at 3 days postinfection. In vivo studies confirmed the in vitro situation. There was a marked difference in the amount of virus present in the osteoid bone matrix and the osteocytic lacunae of osteopetrotic bones from susceptible and G-B1 chickens. In contrast to the bone lesions from susceptible animals, budding virus particles were not detectable in lesions from G-B1 chickens. There was no difference in the amount of virus in osteopetrotic and non-osteopetrotic bone of susceptible chickens suggesting that virus replication alone is not sufficient for induction of osteopetrosis and that an additional specific virus-cell interaction is required. The relative resistance of strain G-B1 may therefore, be a consequence of a reduced frequency of this interaction. Its basis may be the lower amount of integrated, as well as unintegrated, viral DNA.

Animals↗
PubMed1986

Fluoride content of water, dust, soils and cereals in the endemic dental fluorosis area of Khouribga (Morocco).

The fluoride contents of drinking water, dust, soil, straw, raw barley (ears and stems) and barley grains in Khouribga were compared with those from Beni-Mellal, 90 km east of Khouribga where no fluorosis occurs. Identical fluoride levels were found in water samples from both areas, whereas high amounts of F- were in soil, dust, dried straw and dried barley grown in Khouribga. Equilibrated with water, large phosphate rock particles, probably of francolite, and smaller phosphate particles of clay-contaminated francolite, randomly collected in the factories of Khouribga never contained more than 1.2 parts/10(6) F-. Unwashed samples of straw and whole barley had a higher F- content than washed samples. The marked fluorosis in herbivores of the Khouribga area comes more from the ingestion of dust-contaminated food (unwashed straw and unwashed raw barley) with a high fluoride content than from inhalation of fluoride-containing dust. By contrast, the endemic human fluorosis in the same region is mostly due to inhalation of fluoride-containing phosphate dust, and not to fluoride in the drinking water and only exceptionally to fluoride deposited during storage onto cereals, because grains grown in Khouribga have a low fluoride content.

Dust↗
PubMed1986

Theoretical detection of a dark contrast line in twinned apatite bicrystals and its possible correlation with the chemical properties of human dentin and enamel crystals.

Electron microscope images of twinned apatite bicrystals oriented along the [1120] crystallographic direction have been simulated for various experimental conditions, and the validity of the calculation has been checked. These images show a dark contrast line similar to the one observed experimentally in enamel and dentin crystals and therefore strongly suggest the presence of a twin plane parallel to the (1100) crystallographic planes, in these crystals. The presence of a twin boundary in teeth and bone crystals is of prime importance for the adsorption and the dissolution properties of the calcified tissues as a whole.

Apatites↗