Unstable and stable chromosomal aberrations in lymphocytes of people exposed to Chernobyl fallout in Bryansk, Russia.

Analyses of unstable and stable chromosomal aberrations in peripheral blood lymphocytes were used in the assessment of radiation exposure of residents of a village situated in the Chernobyl fallout-contamination zone of Bryansk, Russia. Blood samples were taken from subjects residing in villages with high (> 1100 kBq/m2 137 Cs; Mirnyi) and very low (< 37 kBq/m2 137 Cs; Krasnyi Rog) contamination, 7 years after the Chernobyl accident. The groups were matched by age, sex, smoking habits and previous medical radiological exposures. A total of 200 people (100 exposed, 100 controls) were analysed for the presence of unstable aberrations from Giemsa-stained slides. To study stable aberrations, chromosome painting analyses were performed on 100 subjects (50 exposed, 50 controls), using painting probes for chromosomes 1, 2 and 4 and a pancentromeric probe. People living in the contaminated area showed significantly higher rates of unstable chromosome-type aberrations but not chromatid-type aberrations in their lymphocytes, indicating radiation exposure as a causative factor for the observed difference. No significant differences were found in the aberration rates between the two areas by the chromosome painting method. The levels of chromosome exchanges were low in both populations, but consistently higher in Mirnyi compared with the control area. The magnitude of radiation exposure resulting from Chernobyl fallout was estimated on the basis of excess stable chromosomal aberrations in the lymphocytes of the Mirnyi population compared with the controls.

Morphology of the mandibular cortex on panoramic radiographs as an indicator of bone quality.

OBJECTIVES: To determine whether the bone mineral density (BMD) of the mandibular cortex is correlated with an ordinal classification of the morphology of the inferior cortex on panoramic radiographs. METHODS: The cortical BMD of the mandible was measured by single-energy quantitative computed tomography at two sites: (1) buccally and distally from the mental foramen, (2) lingually and distally from the mental foramen. The morphology of the mandibular cortex was assessed on panoramic radiographs, and classified into three groups. RESULTS: The severity of the changes in the mandibular cortex was significantly related to the BMD of the buccal cortex (ANOVA: p = 0.002). CONCLUSIONS: The use of an ordinal classification of the mandibular cortex on panoramic radiographs may be helpful for general dental practitioners in the assessment of the local quality of the cortical bone.

Thyroid ultrasound findings 7 years after the Chernobyl accident. A comparative epidemiological study in the Bryansk region of Russia.

AIMS: The accident at the Chernobyl nuclear power station occurred in April 1986. We report on a comparative epidemiological study on thyroid abnormalities in the contaminated and uncontaminated populations of the Bryansk region, South-West Russia, in 1993, 7 years after the accident. MATERIAL AND METHODS: The study material consisted of all inhabitants aged 3-34 years in the contaminated village of Mirnyi and in the uncontaminated village of Krasnyi Rog, excluding those who had moved to the villages after the accident. The total material comprised 302 inhabitants in Mirnyi and 200 in Krasnyi Rog. RESULTS: No pathological US findings in either village were found in children born after the accident. In the age group 0-9 years old at the time of the accident, the prevalence of thyroid abnormalities was 8.1% in the contaminated village compared to 1.6% in the uncontaminated village. In the age group 10-27 years the corresponding figures were 18.8% and 17.7%. Only 55% of the pathological US findings were detected by physical palpation. CONCLUSION: The total prevalence of thyroid abnormalities was higher among children in the contaminated village. We recommend an active screening of young contaminated subjects with US, supplemented with fine needle biopsy.

Caries experience and treatment need among adults responding to an invitation for dental examination and treatment in two Karelian communities in Russia.

This study was planned and conducted by the Health Authorities of Karelia in the Russian Federation and the Faculty of Dentistry, University of Kuopio, Finland. The aim of the study was to analyze caries experience and treatment need among adults who responded to an invitation for dental examination and offered free dental treatment in two communities in Karelia. A total of 227 adults aged 30-72 years from 2 rural communities were examined clinically in accordance with WHO criteria by a team of Finnish dental specialists. The participants represented two major ethnic groups (Fenno-Ugrians, 68%; Slavs, 32%). The mean DMFT and DMFS were 15.8 and 58.8, respectively. Among dentate subjects (n = 225) 88% had at least one carious tooth and 80% had one or more filled or crowned teeth. Altogether, 34% of the subjects needed extraction(s), and 83% needed restorative treatment. The main finding of the study was that with regard to caries experience, oral health was quite good compared with that found in Finland and the UK.

Dental caries and stress among South African political refugees.

The aim of this study, which was conducted in a refugee camp of the African National Congress in Tanzania, was to analyze the caries experience in relation to perceived stress and sleeping problems and stressful experiences among South African political refugees. A sample of 194 persons, aged 11 to 39 years, was examined clinically and interviewed. There was a consistent association between caries experience and the different parameters for estimating perceived and experienced stress. In particular, the aggregation of different stress indicators seemed be strongly related to higher caries experience.

Background factors affecting dental caries in permanent teeth of Finnish and Soviet children.

The aim of this study was to analyze the association between some general background factors and caries experience in two groups of Finnish children (from Helsinki and Kuopio) and Soviet children (Moscow and Leningrad). A total of 1187 schoolchildren, ages seven, nine and twelve years, were examined and information about their health habits was gathered by questionnaire. Questions included use of sweets, cakes, soft drinks, sugar-sweetened coffee and tea, toothbrushing frequency and mother's education. Except for age, the factors that explain caries experience clearly differ in Finnish and Soviet children.

Effect of the mineralizing agent on the permanent teeth.

In a two-year pragmatic clinical trial, the effect of the mineralizing agent was evaluated on permanent teeth of the first eruption group among Finnish children (7-years old at the beginning of the study) with a low prevalence of DFS. In the test group (n = 123, biweekly mouthrinsing with a 2% solution of mineralizing agent and 0.2% NaF solution) the percentage reduction in increment of both EFDS and DFS was high, whereas in the control group (n = 123, biweekly mouthrinsing with placebo and 0.2% NaF solutions) the incidence for symptoms of caries disease did not differ from that normally found in this age cohort. Positive clinical effect of tested solution was age-related and was associated with remineralization of old and inhibition of occurrence of new EFD lesions.

Surface-specific effect of a mineralizing agent on the permanent teeth and on periodontal status.

In a two-year clinical trial the surface-specific effect of a mineralizing agent on selected permanent teeth was evaluated as well as the effect of this agent on periodontal health in children. Compared with positive controls (Control group, n = 123, biweekly mouthrinsing with placebo and 0.2% NaF solutions), among children in the test group (n = 123, biweekly mouthrinsing with 2% Remodent and 0.2% NaF solutions) the mineralizing agent clearly affected periodontal health (as determined by the prevalence of subjects with gingival bleeding and occurrence of affected sextants at risk) positively, in addition to having a positive effect on the incidence of EFD lesions. The mineralizing agent tested was not found to have adverse effects (as determined by the prevalence of subjects with dental calculus and occurrence of affected sextants at risk). Use of the mineralizing agent is recommended especially during posteruptive maturation of permanent teeth.

Dento-facial morphology and caries experience: an epidemiological study.

The aim of this study was to analyze the association between occurrence of enamel focal demineralization (EFD) lesions and caries on the smooth surfaces of permanent teeth and some parameters concerning dentofacial morphology in different age groups of Finnish children. Altogether 587 children aged 7, 9 and 12 years living in Helsinki and Kuopio, Finland were examined clinically and some parameters of dento-facial morphology were measured. Of the dento-facial morphological parameters, the size of the gonial angle seemed to be associated with caries indicators. The possible predictive value of dento-facial morphology for caries should be confirmed by longitudinal study.

Mineralizing agents in caries prevention: a review of the effects of Remodent.

Caries reduction from tooth brushing with Remodent occurs according to age, from 37.8% to 83.7% during a two to three year follow-up. The highest reduction was gained when the program was started at the age of 2. When Remodent-solution and -varnish were tested in one to three year follow-up, reductions in caries occurred from 20% to 91%. These studies also showed that the effect was best when the preventive treatment was started early.

Dental health status in 7-year-old children: a basis for mineralizing therapy.

Initial dental health status of permanent teeth among 584 children aged seven years selected for clinical trial with mineralizing agent, Remodent in Varkaus (Finland) and in Moscow (U.S.S.R.) was described and analyzed. These results were compared systematically with those reported previously for the same age groups from the different data. The similarity in patterns of occurrence of EFD lesions and caries and differences in their prevalences between children in the two ethnic groups remained the same. Differences in prevalence of EFD lesions cannot be explained as due to the influence of local branches of Public Dental Health systems (influence on oral hygiene habits and use of fluorides). Differences in prevalence of caries may be explained as being due to the influence of local branches of Public Dental Health systems (use of sealants). The cariogenic situation, measured as a number of EFD lesions, and the activity of these lesions on the smooth surfaces of permanent teeth also remained constant over time. This indicates a need for active caries prevention among children in both ethnic groups.

Factors predicting caries risk in children.

Selection of caries-risk groups is difficult and unreliable. In this study we analyzed the known correlates of caries and their interrelations. The subjects (n = 153) were seventh graders (13 yr old) from a school in Kuopio. Data were collected by mail survey (n = 150), from the clinical registers of the local health center (n = 135), and from a saliva test. In the first stage we computed the bivariate correlates between the D-index and its traditionally defined determinants. In the second stage the predictors of caries risk were ranked using discriminant and multiple regression analyses. The bivariate correlates of caries were: DMF-index of the previous year (r = 0.69), D-index of the previous year (r = 0.59), lactobacillus count (r = 0.26), buffer capacity (r = 0.20), and toothbrushing frequency (r = 0.07). In discriminant analyses the DMF-index among girls and the frequency of consumption of sweets among boys were the only significant discriminators. In the multiple regression analyses, however, the final model (P less than 0.001) for girls included: DMF-index of the previous year (beta = 0.64) and lactobacillus count (beta = 0.31). The corresponding model for boys (P less than 0.001) included: DMF-index of the previous year (beta = 0.55) and frequency of consumption of sweets (beta = 0.24). Using these variables, it is difficult to develop a reliable method for determining the caries susceptible groups, but of them, the DMF-index seems the most reliable for predicting caries risk among children.