Biomedical subjects
Publications and source records attributed to J Vreven.
This study determined the effect of a modification of the drilling technique on the retention of self-threading pins. The drilling technique in two stages significantly increased the retention of self-threading pins.
During the last 20 years, existing data show that caries activity has decreased in some industrialized countries, while marked increases have occurred, often rapidly, in developing countries. Changes in the prevalence of a multifactorial disease like dental caries are difficult to explain but seem to coincide either with increased intake of refined sugar-containing feeding or with the widespread availability of fluorides from many sources, more particularly in the tooth-pastes. The combination of fluorides with different other factors must be considered to explain the reduction in caries prevalence in the 1970's, but only the cariostatic effect of fluorides can be measured significantly. In spite of few studies in Belgium, a trend to a reduction of caries prevalence has been observed in temporary and permanent dentition. The aims of this study are to assess: 1. the oral health in a population of 5 to 21 old schoolchildren 2. and the effect of water naturally fluoridation on the dental caries prevalence. The dental caries prevalence is determined in each age group using the dft, dfs, D (2-4) MFT and D (2-4) MFS indices. The situation in this population is not satisfactory and there is a marked need for better oral health. The D (2-4) MFT increases from 1.67 to 11.29 between 6 and 20 years of age. In each age group, the numbers of carious and untreated surfaces in temporary and permanent dentition are more important than the number of filled surfaces. The percentage of children with caries-free teeth decreases from 27.0 to 0% between 5 and 20 years of age. A relation is recorded between the caries indices and the socio-economic category of the father, with the lowest indices among the higher educational group. The results show that the prevalence of dental caries is significantly lower in lifetime residents of the fluoridated community (Mouscron). Fluoridation reduces but does not eliminate social inequalities. The benefits of water fluoridation have been demonstrated in most countries but fluoridation alone is not sufficient to achieve total prevention.
Today, we know the caries aetiology and prevention rather well. We also know that caries-related levels of dental health are inequitably distributed among social classes: on the average, disadvantaged people experience higher DMFS then privileged people. This difference can be explained by a differential access to health care, which can be shown by the study of components of the DMFS index: proportion of filled surfaces (F/DMFS), proportion of missing surfaces (M/DMFS), and proportion of recurrent caries (secondary caries/filled surfaces). Though we are able to describe the social distribution of levels of dental care, we cannot "explain" the differences we observe. The explanation of those differences defines the field of social epidemiology. This consists in determining the social aetiology of diseases, starting from social determinants of attitudes and behaviors influencing health.
There are many circumstances under which the condition of the pulp calls for root canal work, due to the real or potential risk of pain, infection, inflammation or functional difficulties (acute, irreversible pulpitis, chronic pulpitic conditions, necrosis and its consequences, etc.). Other circumstances exist in which injury to the pulp is not necessarily irreversible: initial pulpitis, iatrogenic fracture of the pulp, traumatisms, dystrophic deteriorations. The high success rate for endodontic therapy could argue for elimination of impaired or necrose-prone pulp. In fact, however, unsuccessful pulpectomies often lead to loss of the dental organ and successful endodontic treatment severely weakens the whole tooth structure and often implies prosthetic restoration, with the consequent increase in tissular loss. In order to preserve pulp and crown tissues, pulpal vitality should be protected in all cases where such conservative efforts do not worsen the prognosis for maintaining the tooth on its arch or jeopardize a planned restoration. Solutions are presented for various types of situations, according to the risks encountered.
The antibacterial activity of camphorated phenol, iodine-potassium iodide, aqueous 2% glutaraldehyde, Rockles 4, Cresophene and Terra-Cortril has been tested in vitro against 21 species of bacteria. After 2 minutes of contact between medication and bacteria, Rockles 4, Cresophene, IKI and camphorated phenol inhibited completely all the tested bacteria. Terra-Cortril and aqueous glutaraldehyde 2% even pures were ineffective against all the bacteria species. Only Cresophene remained effective against 4 bacteria species when diluated 100 times.
The results of a cross-sectional study of the prevalence of caries in a sample of 3,237 children aged 5 to 21 are described in relation to some objectives of the WHO program. The prevalence of caries is high in the sample: 1. 31.5% of the children aged 5 to 6 are free of caries (according to the WHO objectives, 50% of the children aged 5 to 6 should have no caries), 2. the mean number of decayed, missing and filled permanent teeth (DMF/T index) in children aged 11 to 12 is 6.6 (The DMF/T should be less than or equal to 3). The frequency of toothbrushing is distributed as follows: 23% of the children brush their teeth once a week or less, 46% brush their teeth once a day, and 31% brush their teeth twice a day or more. The purpose and the frequency of the consultations at the dentist's office have been examined: 15% of the children never consult the dentist, 44% consult the dentist in case of toothache, and 41% go to the dentist's office for screening or control. Only 3.2% of the children use regularly and appropriately fluoride tablets. Since the variance of the results is large, it is difficult to distinguish explaining variables or determinants. However, the data indicate that social groups show differences in DMF indices as well as in the behaviors associated with dental hygiene and prevention.
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Monoclonal antibodies to Streptococcus mutans OMZ175 (serotype f) cell wall-associated antigens (wall-extracted antigens [WEA]) were derived from the fusion of Lou C plasmocytoma rat cells (IR 983 F) and spleen cells from Wistar R inbred rats immunized with WEA. Four cell lines producing monoclonal antibodies directed against a component of S. mutans WEA have been established. All four monoclonal antibodies reacted only with two antigens of WEA from S. mutans OMZ175 by Western blotting and immunoprecipitation techniques, enzyme-linked immunosorbent assay (ELISA), and competitive ELISA. Western blot analysis of WEA showed that the four monoclonal antibodies recognized two related cell wall-associated proteins with apparent molecular weights of 125,000 and 76,000. Immunoprecipitation of whole cells with the monoclonal antibodies confirmed the surface localization of the two antigens. The ELISA and competitive ELISA were used to analyze the distribution of the epitopes on seven S. mutans serotypes. All S. mutans serotypes were found to express the recognized epitopes; however, different reactivity patterns could be distinguished among the various strains tested, and the four monoclonal antibodies reacted only weakly with S. mutans serotypes d and g.
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The activities of acid and alkaline pyrophosphatases were measured in human plaque of thirty subjects and saliva of twenty-two subjects. A study of correlation and analysis of variance were done between the pyrophosphatasic activity and the calculus index. A significant positive relationship has been established.
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