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Biomedical subjects

V Baelum

Publications and source records attributed to V Baelum.

At least 55 records · Page 3Linked to original sources
PubMed1992

Putative periodontopathogens in "diseased" and "non-diseased" persons exhibiting poor oral hygiene.

The aim of the study was to assess the occurrence of some putative periodonto-pathogens in "test" and "control" sites in "diseased" and "non-diseased" persons, respectively, from an adult rural Kenyan population exhibiting poor oral hygiene and widespread loss of attachment (LA). 14 persons (less than 35 years) were assigned to a "diseased" category on the basis of at least 4 sites with LA greater than or equal to 4 mm; at least 5 mm LA and a pocket greater than or equal to 4 mm interproximally in a lower incisor ("test" site): and less than 2 mm LA and no pocket greater than or equal to 4 mm distal to a lower canine or mesial to a lower first premolar ("control" site). Age-matched "non-diseased" persons were identified on the basis of no sites with LA greater than 2 mm and no pockets greater than or equal to 4 mm associated with LA. Paperpoint samples from test and control sites as well as a scraping sample from the dorsum of tongue were examined for presence of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Bacteroides intermedius, B. melaninogenicus group, Capnocytophaga, Selenomonas spp., and Wolinella recta. P. gingivalis was found in 79% of test sites and 36% of control sites in "diseased" persons, and in 18% and 35% of test and control sites, respectively, in "non-diseased" persons. "No other bacterial group discriminated significantly between test and control sites or between diseased and non-diseased subjects. The surprisingly high occurrence of P. gingivalis in non-diseased subjects, both subgingivally and on tongue, indicates that deep periodontal pockets are not prerequisite ecological environments for P. gingivalis establishment.

Adult↗
PubMed1992

Fluoride concentrations in unerupted fluorotic human enamel.

Unerupted fluorotic human enamel was obtained from teeth surgically removed from patients with dental fluorosis. Fluoride was measured in samples produced by serial acid etching from the surface to the interior of blocks of buccal and lingual enamel. The severity of fluorosis, according to the TF index, was determined from the macroscopic and microradiographic appearance of the specimens. The shape of the fluoride profiles was not affected by the degree of severity of fluorosis, but the fluoride concentrations increased with increasing severity of lesions. Fluoride concentrations were similar to those previously recorded in erupted fluorotic enamel and were not related to the length of time the teeth had been present in the jaws. It was concluded that the fluoride content of erupted fluorotic enamel represents fluoride acquired during tooth formation and that further uptake prior to eruption may be negligible.

Acid Etching, Dental↗
PubMed1991

A random effects model for some epidemiological features of dental caries.

We describe a random effects model for caries lesion development and progression based on considering the effects of the pH fluctuations over time in microbial dental plaque as a Wiener process with a single absorptive barrier. The model predicts that the period of greatest risk to developing caries occurs shortly after eruption, but thereafter the longer a surface survives without developing a lesion, the less likely will it be that a lesion will subsequently develop. The model is able to anticipate why the effect of water fluoridation on caries prevalence is most pronounced when caries is diagnosed at cavity level. This model offers one way in which the variability which characterizes the complex ecosystem associated with dental caries may be considered a subject of interest for enhancing our understanding of its pathogenesis and epidemiology.

Absorption↗
PubMed1990

Effect of cigarette smoking on the transition dynamics in experimental gingivitis.

This paper reports the findings of an experimental gingivitis study conducted in smokers and non-smokers. 33 volunteers were examined and underwent prophylaxis during a period of 4 weeks. 28 subjects who showed a plaque index less than 0.20 on all prophylaxis occasions were permitted to continue in the study. Subjects then had their gingival status recorded, had their teeth polished and were requested to abstain from all oral hygiene measures for the following 21 days. After 5 days, 10 days and 21 days, plaque and gingival status were recorded using the criteria of the plaque index and gingival index. After the examination on day 21, the teeth were polished and oral hygiene was re-instituted. Following 2 weeks of supervised oral hygiene, recordings of plaque and gingival status were performed. At the initial examination, there was no difference between the clinical assessment of plaque and gingival status in smokers and non-smokers. Similar amounts of plaque accumulated in the 2 groups during the period of no oral hygiene, but smokers exhibited less gingival inflammation assessed clinically than non-smokers. This difference occurred as a result of an apparently lowered incidence rate and a markedly higher recovery rate in smokers compared to non-smokers. These findings may indicate that smokers for reasons yet unknown have a reduced capacity to mount and maintain an effective defense reaction to a given plaque challenge.

Adult↗
PubMed1990

A new approach to investigating associations in periodontal disease data.

This paper presents a method for the analysis of data originating from studies of destructive periodontal disease. The proposed method is an extension of the Mantel-Haenszel technique for the analysis of case-control studies and allows for expression of the site-specificity of destructive periodontal disease while maintaining the individual as the unit of analysis. Using data originating from a cross-sectional study of periodontal breakdown and oral hygiene parameters in a random sample of adult rural Kenyans, the proposed method is illustrated and the results compared with results obtained when two alternative analytical methods are used. The results demonstrate that the choice of analytical strategy may have profound implications for the conclusions to be drawn. Depending on the strategy chosen, one may draw conclusions which are qualitatively different and the present study indicates that the direction of these differences is not predictable.

Adolescent↗
PubMed1990

The nature and mechanisms of dental fluorosis in man.

Any use of fluorides, whether systemic or topical, in caries prevention and treatment in children results in ingestion and absorption of fluoride into the blood circulation. The mineralization of teeth under formation may be affected so that dental fluorosis may occur. Dental fluorosis reflects an increasing porosity of the surface and subsurface enamel, causing the enamel to appear opaque. The clinical features represent a continuum of changes ranging from fine white opaque lines running across the tooth on all parts of the enamel to entirely chalky white teeth. In the latter cases, the enamel may be so porous (or hypomineralized) that the outer enamel breaks apart posteruptively and the exposed porous subsurface enamel becomes discolored. These changes can be classified clinically by the TF index to reflect, in an ordinal scale, the histopathological changes associated with dental fluorosis. Compared with Dean's and the TSIF index, we consider the TF index to be more precise. Recent studies on human enamel representing the entire spectrum of dental fluorosis have demonstrated a clear association between increasing TF score and increasing fluoride content of the enamel. So far, no useful data on dose (expressed in mg fluoride/kg b.w.)-response (dental fluorosis) relationships are available. In this paper, we have, therefore, re-evaluated the original data by Dean et al. (1941, 1942), Richards et al. (1967), and Butler et al. (1985) from the USA, by applying the equation of Galagan and Vermillion (1957) which permits the calculation of water intake as a function of temperature.(ABSTRACT TRUNCATED AT 250 WORDS)

Dental Enamel↗
PubMed1990

The effect of a single dose of 1-hydroxyethylidene-1, 1-bisphosphonate (HEBP) on presecretory ameloblast differentiation in rat incisors.

A single, high dose of HEBP to rats results in a triad of lesions along the mineralizing front of the incisor enamel. One type of lesion is a shallow groove crossing the apical enamel surface. The purpose of this study was to explore the pathogenesis of this "demarcation groove", and to characterize changes in the involved regions of amelogenesis. Rats were given a subcutaneous dose of 10 mg/kg body weight of HEBP and sacrificed by vascular perfusion at intervals ranging from 1 to 36 hours. Mandibular incisors were processed for light and electron microscopy. The region of ameloblasts facing dentin was divided into two subregions: A region of ameloblasts facing unmineralized dentin, comprising a posterior (Aud/p) and an anterior portion (Aud/a), and a region of ameloblasts facing mineralized dentin (Amd). The progressive apical mineralization of the predentin was arrested up to 12 hours after injection of HEBP, while ameloblasts related to already mineralizing dentin continued to differentiate and secrete enamel matrix. At 8 hours the dentin and enamel layers had assumed a common apical border at the start of Amd, marking the position of the future demarcation groove. The length of Aud/p remained constant, Aud/a doubled in length, and Amd was drastically reduced up to 24 hours after injection of HEBP. The normal migration rate of the ameloblasts was unaffected by HEBP. Accumulations of ameloblast secretory products occurred at certain time intervals between the cell apices, but no morphological changes were recorded in the organelles. Most of the changes observed may be indirect in nature resulting from the physico-chemical effect of HEBP on normal mineralization of dentin and enamel. However, further studies are needed to elucidate possible direct cellular effects on ameloblasts.

Ameloblasts↗
PubMed1990

Dental health of children and adults in Guinea-Bissau, West Africa, in 1986.

The aim of the present study was to assess the dental health situation of a relatively urban population in Guinea-Bissau, West Africa. A total of 312 persons aged 12, 30-39 and 50-59 years, respectively, were examined for dental caries, oral hygiene, periodontal pockets, gingival recession and mobility of the teeth present. The state of their oral hygiene was very poor. Although most persons examined had a relatively high number of teeth present a substantial number of these teeth had carious lesions, many of which were rather deep. Teeth with increased mobility were seen in a number of individuals but it appeared that periodontal breakdown was not the major cause of tooth mortality in the majority of the population. The results suggest that future dental health care strategies should focus on the development of a new type of dental health worker. This health worker should be capable of performing simple extractions, simple restorative treatment and intercepting early ongoing carious lesions using modern biologically-founded principles and appropriate technology.

Adult↗
PubMed1989

Black-pigmented Bacteroides species and Actinobacillus actinomycetemcomitans in subgingival plaque of adult Kenyans.

A microbiological study was performed of the subgingival plaque on 2 sites in each of 20 adults originating from a rural area 40 km outside Nairobi, Kenya. The recovery rate of B. gingivalis was 70%, of B. intermedius 100% and of A. actinomycetemcomitans 40% of the subjects, and 50%, 90% and 28%, respectively, of the sites. The isolated strains exhibited similar biochemical characteristics and antibiotic susceptibility pattern as type strains of these species. The high recovery rate of these 3 bacterial species in adult Kenyans was a rather surprising finding, since pathological pocketing was found only sporadically. Furthermore, the results of 2 methodological approaches tested demonstrated that such microbiological studies can be carried out in countries with limited laboratory facilities.

Actinobacillus↗
PubMed1989

Tooth mortality and prosthetic treatment patterns in urban and rural Chinese aged 20-80 years.

The study describes tooth mortality levels and pattern of prosthetic treatments in a sample of 1744 Chinese aged 20-80 yr who are residents of Beijing area. Complete edentulousness was rarely seen before the age of 60 yr. Beyond this age up to 26% were edentulous, depending on age and sex. The mean number of teeth present ranged from 10.0 to 29.7 depending on age, sex, and area of residence. Below the age of 60 yr very few persons had experienced extensive loss of teeth but thereafter the number of teeth missing was substantially increased. Prosthetic treatments in the form of partial dentures, crowns, and bridges were frequently observed even in the younger age groups. In all age groups the number of teeth exhibiting caries lesions involving the pulp was much higher than the number of teeth exhibiting extensive mobility. Although many people retain a high number of teeth even late in life our findings indicate a substantial need for, in particular, relief of pain services. Concurrently, emphasis must be placed on preventive programs aiming at interfering with ongoing disease.

Adult↗
PubMed1989

Langerhans cells in oral epithelium of chronically inflamed human gingivae.

This study describes the histopathological features and the distribution of oral epithelial Langerhans cells in 19 gingival biopsies originating from an adult Tanzanian population characterized by very poor oral hygiene and severe gingival inflammation. Light-microscopically, all biopsies contained often large inflammatory connective tissue infiltrates, 6 of which predominantly contained plasma cells while the rest were dominated by lymphocytes. Seven specimens contained peculiar accumulations of round lymphoid and dendritic cells in the lower cell layers of the oral epithelium. These phenomena have not previously been demonstrated in human gingiva and deserve further attention in studies on the pathogenesis of periodontal diseases. Immuno-histochemical staining with OKT6, OKT4 and OKT8 antibodies showed markedly increased numbers of OKT6-positive cells in 7 specimens and clusters of OKT4- and OKT8-positive cells in the oral epithelium of 4 specimens. High numbers of OKT6-positive cells were not related to the presence of intra-epithelial, non-keratinocyte infiltrates or large connective tissue infiltrates. The variable numbers of oral epithelial Langerhans cells may therefore result from different bacterial antigens elucidating different responses or, alternatively, reflect different responses to similar plaque antigens penetrating the surface of the oral epithelium.

Adult↗
PubMed1989

Transition dynamics in experimental gingivitis in humans.

This study was conducted in order to investigate the dynamics of the gingival inflammatory status during periods of plaque accumulation and thorough oral hygiene. After a period of prophylaxis, 42 volunteers were asked to abstain from all oral hygiene measures for 2 weeks, whereafter oral hygiene was reinstituted. In the absence of oral hygiene, plaque was found at virtually all sites after 7 days and the number of sites with gingivitis increased simultaneously. A reduction in gingival inflammation occurred subsequent to plaque removal. During phases of both plaque accumulation and thorough oral hygiene, sites were found to convert from non-inflamed to inflamed status concurrently, as in the reverse direction. No association between plaque and gingivitis was revealed. The gingival status of a single site was a poor predictor of its status on the subsequent occasion. The proportion of inflamed sites converting to non-inflamed status was greater than the proportion of non-inflamed sites converting to inflamed status at any time. The estimated incidence rate remained fairly constant during both the plaque accumulation phase and the oral hygiene phase, whereas the estimated recovery rate was considerable lower during the plaque accumulation phase compared to oral hygiene phase. The clinical appearance is the outcome of the dynamics between these rates. The steady-state prevalences derived from the estimated "incidence" and "recovery" rates were quite similar to the actual findings after 14 d of plaque accumulation and the subsequent 10 d of thorough oral hygiene.

Adult↗
PubMed1989

Pattern of dental caries in an adult rural population.

A study was conducted amongst 1,131 randomly selected persons aged 15-65 years in a rural area of Kenya, having minimal access to dental care. A relatively low prevalence of frank cavitation was found in the 15- to 24-year-old cohort, but in the older age groups over 80% were so affected. Caries in the youngest cohort was characterized by a predominance of enamel lesions. At the age of 25-34 years, however, involvement of pulpal tissues and loss of teeth due to caries was more common, and this age group exhibited the largest number of dentinal lesions. The 35- to 44-year-old cohort exhibited fewer enamel and dentinal lesions, but more pulpally involved lesions and more extracted teeth. In the group aged 45-54 years, enamel and dentinal lesions were less common, and at the age of 55-65 years, such lesions were less common in comparison to their occurrence in younger cohorts. The 55- to 65-year cohort could generally be characterized as having larger numbers of root surface lesions, lesions involving the pulp, and extracted teeth. Root surface lesions were principally associated with age over 35 years. In all age groups caries exhibited a skewed distribution, most of the lesions occurring in a minority of individuals. This study demonstrates that caries activity continues throughout life and is not a phenomenon confined to any one period of life.

Adolescent↗
PubMed1989

Associations between salivary levels of Streptococcus mutans, Streptococcus sobrinus, lactobacilli, and caries experience in Kenyan adolescents.

Salivary levels of mutans streptococci (S. mutans and S. sobrinus) and lactobacilli were determined in a random sample of rural Kenyans between 15 and 19 years of age (n = 149). It is possible for the natural history of dental caries in this population to be studied since it is characterized by a limited access to conventional dental treatment. Using a short set of biochemical tests, we identified from seven to ten presumptive mutans streptococcus colonies--cultured from the saliva of each individual--to differentiate between S. mutans and S. sobrinus. No colonies resembling S. rattus (S. mutans serotype b) were isolated. Lactobacilli were identified as Gram-positive, catalase-negative rods. The mean D1-4MFS and D3-4MFS were 7.03 +/- 6.43 and 1.46 +/- 3.44, respectively. The mean mutans streptococcus and lactobacillus levels were 8.7 x 10(4) and 6.7 x 10(4), respectively. The salivary mutans streptococcus and lactobacillus levels were significantly correlated (p less than 0.01). Of the subjects, 64% harbored only S. mutans, 4% only S. sobrinus, 30% both species, and 2% neither. Lactobacilli were ubiquitous. The caries experience of the group was significantly (p less than 0.001) correlated with both the total salivary level of mutans streptococci and the salivary S. mutans levels, but not with the salivary S. sobrinus level.

Adolescent↗
PubMed1989

Dental caries in adult and elderly Chinese.

This paper reports on a study of dental caries conducted among 1744 urban and rural Chinese (from 20 to 80 years old), who were selected by means of a systematic stratified sampling procedure. The prevalence of one or more decayed or filled teeth ranged from 48 to 90% in urban residents, and from 51 to 97% in rural residents, depending on age. The mean number of decayed or filled teeth ranged from 1.2 (+/- 1.9) among 20-29-year-olds, to 6.2 (+/- 5.5) among 70+-year-olds, and was highest among rural residents. Among 20-29-year-olds, the main components of the DFT were enamel lesions and fillings. Among 30-49-year-olds, the DFT consisted mainly of enamel lesions and filled teeth, as well as teeth with lesions involving the pulpal tissues. In subjects over the age of 50 years, lesions involving pulpal tissues were the predominant type, followed by root-surface lesions. In subjects below the age of 50 years, most of the caries experience derived from coronal surfaces, particularly occlusal surfaces. Root-surface caries was predominantly a feature of persons aged 50 years and above. Despite a large number of surfaces being at risk of root-surface caries, less than 10% of the surfaces were so affected. Although cross-sectional in nature, these data indicate that when the oral hygiene standards are poor, caries lesions continue to develop and progress throughout life. With age, dental caries becomes a substantial oral health problem in this population of adult and elderly Chinese, despite the availability of some dental services.

Adult↗
PubMed1989

Enamel fluoride in relation to severity of human dental fluorosis.

The aim of this study was to test whether the concentrations of fluoride in fluorotic human enamel are related to the degree of severity of dental fluorosis classified according to the index described by Thylstrup and Fejerskov. Teeth representing the entire spectrum of human dental fluorosis were analyzed. Fluoride concentrations were determined by serial acid-etching from surface to interior of blocks of enamel cut from each tooth. Fluoride was measured by ion electrode and calcium by atomic absorption spectrophotometry. The results showed that the pattern of distribution of fluorotic enamel is similar to that described for normal enamel. Increasing severity of fluorotic lesions was associated with increasing concentrations of fluoride throughout the enamel. It is concluded that although further studies are required to establish the relative contribution of fluoride which may be taken up posteruptively by fluorotic enamel, the findings support the hypothesis that the TF index reflects increasing exposure to fluoride during tooth development.

Chi-Square Distribution↗
PubMed1989

Chewing sticks, toothpaste, and plaque removal.

The aim of the present study was to assess the efficacy of brushing with chewing sticks in removing plaque and to evaluate whether toothpaste has any additional effect on the removal of established dental plaque. Kenyan schoolchildren had their plaque deposits disclosed by means of disclosing tablets and subsequently recorded on four buccal sites of all permanent teeth. The children were then allocated to two groups in a crossover design; in one group the children brushed with chewing sticks and toothpaste; the other group brushed with chewing sticks only. Substantial amounts of plaque were recorded at base line in most children. Brushing with a chewing stick for 5 min resulted in a net reduction of the proportion of plaque deposit sites per child. Toothpaste resulted in no additional effect.

Adolescent↗