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Biomedical subjects

F Gehring

Publications and source records attributed to F Gehring.

At least 19 recordsLinked to original sources
PubMed1990

[In-vitro plaque accumulation on different filling materials].

The influence of the surface roughness of dental filling materials as well as of specific properties of materials on plaque accumulation was to be tested in a comparative study for various materials (Degulor S, Amalcap SAS, Visio Dispers, Ketak-Fil, CuproDur, Harvard Cement) was to be tested in a comparative investigation. For this purpose, the different materials were placed in a Streptococcus mutans NCTC 10449 culture medium containing sucrose, and incubated for three days at 37 degree C. Following this, the specific accumulation of polysaccharides formed outside of cells (plaque) was subjected to gravimetric analysis. Filling materials that take a high polish (Degulor S, Amalcap SAS, Visio Dispers) accumulated only 25 to 50% as much plaque as did cements. Within the group of cements there were also differences (up to 40%) in spite of similar surface roughness. These differences are presumably due to properties specific to the materials. In preliminary examinations of the products named, antibacterial effects were registered in three cases (Degulor S, Harvard Cement and Cupro-Dur--inhibiting areola between 1 and 7.5 mm).

Dental Amalgam↗
PubMed1990

[Demonstration of Streptococcus sobrinus in human oral cavity].

From 133 saliva samples of humans we isolated 32 strains (24%) of Streptococcus sobrinus on an BYCSB selective medium. The very hard colonies of S. sobrinus on this medium were characterized by a distinct chalky white halo of water insoluble glucan ("glucan-halo") produced in large amounts from the sucrose by extracellular glucosyltransferase which has diffused out into the isolation medium. All of the isolated S. sobrinus strains fermented ordinarily mannitol and sorbitol, but not raffinose and melibiose. The occurrence of this special subspecies within the S. mutans-group may play a more important role in the etiology of dental caries of caries-active persons in the future.

Colony Count, Microbial↗
PubMed1990

[Possibilities of assessing the individual caries risk using microbiological parameters].

The most commonly used microbiological tests for identifying patients with high caries activity are based on quantitative or semi-quantitative counts of Streptococcus mutans and Lactobacilli. In a review the prognostic value of such tests is discussed and shown, that in spite of partially high prediction rates, the prognostic value of either S. mutans or Lactobacillus tests can be confirmed only in combination with additional relevant clinical parameters (e.g. anamnesis, DMF-increment, secretation rate and bufferin capacity of saliva...).

Colony Count, Microbial↗
PubMed1990

[Inhibition of caries by Na-saccharin].

The inhibition of dental caries by Na-saccharin was studied in an optimized and standardized experiment with cara rats. The animals were given a cariogenic diet ad libitum as well as under controlled frequency feeding conditions. The addition of 0.5% Na-saccharin to the cariogenic diet produced no cariostatic effects. Ancilliary microbiological in vitro and in vivo experiments showed no appreciable bacteriostatic effects on the cariogenic bacteria flora.

Animals↗
PubMed1989

[Microbiological in vitro and animal experiments assessing the cariogenic potential of various snacks].

Microbiological in vitro and animal experiments were performed to determine the cariogenic potential of different snacks. The determination of the oral salivary sugar clearance time by the aid of a cariogenic S. mutans strain as standard for the cariogenic potential resulted in a relatively high clearance time when a praline was consumed, according to a high cariogenic potential. When consuming a "safe for teeth"-product no easily fermenting substances in the saliva can be shown, suggesting a lacking cariogenic potential. The cariogenic potential of banana, milk-chocolate, Milchschnitte, Müsli-Frucht-Schnitten (cereals and fruits) is between that of the praline and the "safe for teeth"-product. The animal experiments showed in increasing strength of fissure caries after programmed feeding of the following snacks: Basic-diet----milk-chocolate----positive control-diet/Milchschnitte Müsli-Frucht-Schnitten----banana. The highest caries values occurred after having fed banana, the lowest after having fed milk-chocolate. Milchschnitte and Müsli-Frucht-Schnitten showed similar caries values which were between the values after feeding of milk-chocolate and banana.

Animals↗
PubMed1989

[A selective, need-oriented prevention program for primary schoolchildren - results after two years].

427 first grade pupils from primary schools in Göttingen participated in a selective, need-oriented preventive program. Following a clinical examination and an additional saliva test the children were assigned to three risk groups, according to the severity of the initial findings. Each group received preventive care of varying intensity. Two years later the children of risk group 1 ("minor caries risk") showed a mean 0.5 and those of risk group 2 ("medium caries risk") a mean 1.0 new DF surfaces. In the children of the high caries risk group the average caries increment was 1.8 DF surfaces. The degree of sanation of the deciduous teeth could be improved from 10% to 47% within the two years' test period. The saliva tests revealed that the number of cariogenic organisms was markedly reduced in the course of the preventive program.

Child↗
PubMed1989

[Predictive potential of a microbiological caries activity test in preschool children--2-year results].

In a clinical trial the predictive potential of a microbiological screening test for identifying patients with increased caries activity was evaluated. Within a period of 2 years microbiological data and caries increments were found to correlate well. Of the results in 113 preschool children, only 4 proved to be false negative, i.e. only 4 children were wrongly allocated to a non-risk group. As the test is easily handled, it is excellently suited both for group and individual screening programs.

Child↗
PubMed1986

Prevalence of dental caries and Streptococcus mutans in Meo of Northern Thailand.

The prevalence of dental caries was studied in 505 Meo, a minority of Northern Thailand, using the DMFT index. Plaque material from all patients was examined qualitatively for S. mutans. The DMFT (dmft) index score ranged between 1.69 and 7.06 with a mean of 2.17 +/- 3.24 for men and 3.45 +/- 3.72 for women. There was a statistical difference in caries prevalence between males and females (P less than 0.05). There was no statistical correlation between miang chewing and caries prevalence. Fluoride concentration of water samples was between 0.043 and 0.077 ppm F-. Of 505 plaque samples, 13.3% were positive for S. mutans, mostly of biotype I. Compared to other Northern Thai hill tribes and the Thai rural population, the Meo appear to have a higher dental caries prevalence rate.

Adolescent↗
PubMed1985

Streptococcus mutans and caries prevalence in rural Thai.

The prevalence of dental caries was studied in 521 rural Thai using the DMFT index. The oral habit of chewing betel nut was recorded. Samples of drinking water were examined for fluoride concentrations. Plaque material from 500 patients was examined qualitatively for S. mutans. The DMFT (dmft) index score was comparably high for patients under 10 yr of age (4.12); the difference between the DMFT (dmft) score of this age group and the other age groups was statistically significant. The average DMFT (dmft) score was 1.34 +/- 2.67. There was no relation between oral habits and caries prevalence. Fluoride concentrations of the water samples were between 0.11 and 1.64 ppmF- X 14.2% of 500 plaque samples were positive for S. mutans, predominantly of biotype I. The higher prevalence of caries in children may be attributable to changing patterns of life and nutrition.

Adolescent↗
PubMed1984

Streptococcus mutans and caries prevalence in Lisu and Karen of northern Thailand.

The prevalence of dental caries was studied in 139 Lisu and 167 Karen using the DMF-T index. Oral habits were recorded, including the chewing of betel nut. Samples of drinking water and betel constituents were collected and assayed for fluoride concentrations. Plaque material from 100 randomly selected individuals from each village was examined qualitatively for S. mutans. The DMF-T index scores for both tribal groups were low (0.00-1.00), and there was no significant difference in caries prevalence between betel chewers and non-chewers. Fluoride concentrations of the water samples were comparably low (0.02-0.29 ppm F). 30% of 200 plaque samples were positive for S. mutans, mostly of Biotype I.

Adolescent↗
PubMed1984

Relatedness and classification of Streptococcus mutans and "mutans-like" streptococci.

The "mutans-like" streptococci can be separated into five species (Streptococcus mutans, S. rattus, S. sobrinus, S. cricetus, and S. ferus) that belong to the same rRNA homology cluster. New valuable chemical characters for differentiation of the five species--such as peptidoglycan type, presence of cell wall teichoic acid, and cell wall sugar composition--are described. The peptidoglycan type and the cell wall sugar composition can be determined by rapid procedures.

Animals↗