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Biomedical subjects

C van Loveren

Publications and source records attributed to C van Loveren.

At least 19 recordsLinked to original sources
PubMed2002

[Double teeth].

Double teeth are not really rare, but it is still enigmatic why and how they develop. Based upon the clinical, morphological and anatomical appearance and the number of teeth in mouths with double teeth, the double teeth are labelled as products of 'fusion' and 'clefting', but the criteria to attach such etiological names are lacking. It is assumed that heredity is involved in the development of double teeth. Therefore it is attempted to explain why only one of a homozygotic twin had a double tooth.

Child, Preschool↗
PubMed2001

The role of diet in caries prevention.

Over the last three decades the condition of the teeth of children has improved tremendously. This has generally been attributed to the increased use of fluoride toothpaste. During this period the total amount of sugars disappearing into the population per capita has hardly changed. This suggests that the relationship between diet and caries has to be reassessed, which provokes different opinions among dental experts. Some suggest a maximum threshold level for the daily amount of sugars to prevent caries. Others propose that in general the amount of sugars eaten is not an important determinant of caries experience. The scientific evidence for the various opinions on the role of diet in caries development will be discussed. It is concluded that the role of diet is not so much related to the diet itself but to the individual behaviour of people. Where oral hygiene and fluoride supplementation are adequate, the diet has become a lesser factor in caries prevention. However, those diets may cause caries when there is too little fluoride. It is a mistake to classify a diet as cariogenic it may be potentially cariogenic. When one wants to decrease this potency, one should modify those factors that are actually controlling it, which is, in most cases, the topical presence of fluoride and not the composition of the diet. A model is proposed to guide caries prevention. The (insufficient) use of fluoride, (insufficient) oral hygiene and (insufficient) clearance by saliva form a window of risk. The total burden of cariogenic food that can be seen through the window constitutes the actual caries risk.

Child↗
PubMed2001

Dental considerations for dietary counselling.

A decline in the prevalence of dental caries over three decades has occurred without a significant change in the consumption of fermentable carbohydrates, indicating that good dental health is achievable with the presence of cariogenic factors in the diet. Since, in many countries 80% of the caries is present in only 20% of the population, 'targeted intervention' would seem a better preventive option, stressing the judicious use of fluoride, plaque control, fissure sealants and a sensible diet. Dietary modification is notoriously difficult to achieve, being incumbent upon the subject's willingness to effect a change in behaviour. Many texts refer to the frequency of consumption of carbohydrates as being all-important, recommending a reduction in the frequency. However, recent evidence suggests it is the frequency of toothbrushing with a fluoride containing dentifrice which is of fundamental importance in promoting remineralisation of enamel. Dietary advice should be formulated which is both realistic and positive. Trying to dissuade children from consuming products, which they perceive to be tasty and pleasurable is counter productive and more emphasis should be given to tooth brushing using a fluoride toothpaste. Also, a fundamental shift away from the idea of 'good foods versus bad foods' is required and more emphasis laid on good diets as opposed to bad diets. Children should be able to enjoy foods traditionally considered 'bad' from a dental viewpoint, as long as they brush their teeth with a fluoride containing dentifrice and have a sensible approach to their consumption.

Bottle Feeding↗
PubMed2000

The effect of triclosan toothpaste on enamel demineralization in a bacterial demineralization model.

Triclosan has been incorporated into toothpaste to enhance inhibitory effects on bacterial metabolism in dental plaque. Many studies have confirmed these effects by showing a reduction of accumulation of dental plaque, gingivitis and calculus. However, there is no evidence for triclosan having an inhibitory effect on the dental plaque-induced demineralization of the dental hard tissues. Therefore, the effect of 0.3% triclosan added to non-fluoride and fluoride toothpaste was tested in an in vitro model, in which bovine enamel specimens were to be demineralized by acids produced in overlaying Streptococcus mutans suspensions. In a first set of experiments the toothpastes were added to the S. mutans suspensions at 1:100, 1:1000 and 1:10,000 (w/v) dilutions. After 22 h incubation at 37 degrees C the suspensions were removed and assessed for calcium and lactate content, and pH. In this set of experiments, triclosan had no additive protective effect to the non-fluoride or fluoride toothpaste. In a second set of experiments, the enamel specimens were immersed daily for 3 min in 30% (w/v) slurries of the toothpastes before the 22 h incubation with the S. mutans suspensions. Under these conditions, triclosan showed an additional protective effect compared with non-fluoride toothpaste at a low concentration of S. mutans cells (0.07 mg cells dry weight per 600 microL suspension). It is concluded that the enamel surface may act as a reservoir for triclosan, which may protect the enamel surface against a mild acid attack. In combination with fluoride, however, as in toothpaste, triclosan has no additional protective effect against demineralization.

Animals↗
PubMed1999

Protection of dentin by triclosan toothpaste in a bacterial demineralisation model.

The effect of the addition 0.3% triclosan to a non-fluoride and fluoride toothpaste was tested in an in vitro demineralisation model. This model comprised bovine dentin specimens overlaid with acidogenic Streptococcus mutans suspensions in agarose at two different concentrations of cells. Before the experiments, subsurface lesions were made in the dentin specimens in a methylcellulose gel system. In a first set of experiments, the toothpastes were diluted in the S. mutans suspensions at w/v dilutions of 1:100, 1:1,000, and 1:10,000, respectively. After 22 h of incubation at 37 degrees C, the suspensions were removed and assessed for calcium, lactate and pH. In this set of experiments, an additive protective effect of triclosan to the non-fluoride toothpaste was found at the lowest concentration of S. mutans cells and when the toothpaste was relatively undiluted (1:100 w/v). No additive effect was observed to the fluoride toothpaste. In the second set of experiments, the specimens were immersed daily for 3 min in 30% (w/v) slurries of the toothpastes before the 22-h incubations with the S. mutans suspensions. At the lowest concentration of S. mutans cells, triclosan had an additional protective effect to the non-fluoride and fluoride toothpaste. It is concluded that triclosan may contribute to the protection of dentin under a mild acid attack both when it is present in dental plaque and when it has been adsorbed to the dentin.

Adsorption↗
PubMed1999

Fluoride mechanisms.

This article discusses fluoride mechanisms in relation to dental caries. The authors specifically address firmly bound versus loosely bound fluoride; different fluoride active ingredients; fluoride and demineralization and remineralization; fluoride slow-release devices and F-releasing dental materials; antimicrobial effects of fluoride; the uptake of fluoride by oral bacteria; inhibition of enolase, protein-intruding ATPase and sugar transport; the various aspects of plaque as it relates to fluoride; and the rational use of fluoride.

Anti-Bacterial Agents↗
PubMed1998

Incidence of mutans streptococci and lactobacilli in oral cleft children wearing acrylic plates from shortly after birth.

Children with a palatal cleft can be treated with preoperative infant orthopedics including an acrylic plate that is applied shortly after birth to obturate the cleft. It is advised to wear these plates until the 18th month of age. Such a plate, being a hard non-shedding surface, may be expected to facilitate early colonization of mutans streptococci. The first aim of the present investigation was to assess the incidence of mutans streptococci and lactobacilli in children with cleft lip and/or palate during the first 2 years of life. The second aim was to study whether preoperative orthopedics, that is, the wearing of an acrylic plate, had facilitated the establishment of mutans streptococci and lactobacilli. The third aim was to determine other factors associated with colonization of these organisms in these children. Sixty-two Caucasian Dutch children with cleft lip and/or palate participated in this study. Twenty-four of these children were treated with preoperative infant orthopedics and had been wearing an acrylic plate from within a few days after birth. At regular control visits plaque and saliva samples and samples from the surface of the acrylic plate were taken, while a dental examination was performed to document the emergence of the primary teeth, caries status, gingival condition and oral hygiene procedures. Saliva samples were also taken from the accompanying parents. At the visit at the age of 18 months, the parents were interviewed using a structured questionnaire. At this age, the prevalence of mutans streptococci and lactobacilli was compared to that in a control group of non-cleft children. The oral cleft children wearing an acrylic plate from shortly after birth were colonized earlier with mutans streptococci and lactobacilli than the non-plate oral cleft children. In the children wearing acrylic plates, the prevalence of lactobacilli decreased with age, while the prevalence of mutans streptococci increased. At the age of 18 months the prevalence of mutans streptococci was comparable in both groups of oral cleft children and in the control children. There was no relation between the numbers of mutans streptococci in the saliva of the mothers and their children. The presence of mutans streptococci in the saliva of the oral cleft children was significantly associated with between-meal snacking and with the presence of lactobacilli.

Acrylic Resins↗
PubMed1998

Colonization with mutans streptococci and lactobacilli and the caries experience of children after the age of five.

Some authors suggest that there is a "window of infectivity" for mutans streptococci (MS) at an early age, after which colonization is not likely to occur. Moreover, children with low or non-detectable levels of MS at an early age are at lower risk for caries. It was our aim to study caries experience and colonization with MS and lactobacilli in a group of children at 11 years of age who had been documented to have been MS-free until 5 years of age. For this group, the mfs and MFS values at 11 years of age were found to be 1.12+/-2.81 and 0.44+/-0.88, respectively. These values are much lower than those of a control group of 11-year-old children who had always been MS-positive since the age of 2, being 3.10+/-3.43 and 1.20+/-1.91, respectively. Of the 30 children without detectable MS up to the age of 5, 22 had acquired MS at 11 years of age, but their MS counts were significantly lower than those of the control group. No correlation was observed between the levels of MS of the children and the mothers. In children at 11 years of age, no differences were found in the numbers of lactobacilli and sugar intakes per week between the children MS-free and the children MS-colonized at 5 years of age. The present study indicates that the acquisition of MS is still possible after the so-called "window of infectivity" and that a delayed acquisition of MS may reduce the caries experience in the primary and permanent dentition at a later age.

Age Factors↗
PubMed1998

Transmission of mutans streptococci between mothers and children with cleft lip and/or palate.

OBJECTIVE: The aim of this study was to investigate the transmission of Streptococcus mutans between children with cleft lip and/or palate and their mothers. DESIGN: Saliva samples of 21 mother-child pairs were collected and cultured on plates containing a selective growth medium for mutans streptocci. At least five separate colonies of each colony morphotype were isolated. A polymerase chain reaction (PCR) with randomly chosen primers was used to type the isolates. RESULTS: The number of morphotypes and PCR types was significantly lower in the children than in the mothers. Significant correlations were found between the number of morphotypes and PCR types, in the children as well as in the mothers. In only 38% of the mother-child pairs were the same PCR types found in mother and child. CONCLUSIONS: This suggests that S. mutans had been transmitted from mother to child in one-third of the population studied. No correlations were found among the number of colony-forming units, the number of colony-colony-morphotypes, and the number of PCR types of the mothers and transmission. Similar PCR types in mother and child were found significantly more often in children who had more than one PCR type. The results indicate that transmission of S. mutans from mother to child is not frequent in children with oral cleft. This may have consequences for preventive treatment of cleft lip and/or palate children and their mothers.

Chi-Square Distribution↗
PubMed1998

[Dental caries, dental fluorosis and use of fluoride tablets. Results of survey by 8, 14, and 20 year old insurance patients].

OBJECTIVE: To assess the prevalence of fluorosis at the age of 8, 14 and 20 years; to evaluate the prevalence of caries and fluorosis at the age of 8 and 14 years in relation tot the use of fluoride tablets during the first 5 years of age. DESIGN: Retrospective study. SETTING: The investigation was carried out in four cities in the Netherlands. METHODS: Caries and fluorosis data were obtained in 8-, 14- and 20-year-old persons by clinical examination. For 8- and 14-year-olds results were compared with data about the use of fluoride tablets during the first 5 years of life. These data were obtained by questionnaires completed by the parents when the child was 5 years old. RESULTS: Prevalence of fluorosis in permanent teeth of 8-, 14 and 20-year-olds was 16%, 31% and 26% respectively. Univariate analysis revealed a statistically significant relation between the frequency of the use of fluoride tablet and caries prevalence in deciduous and permanent teeth on the age of 8. Prevalence of fluorosis and fluoride tablet use did not show such a relation. These findings were confirmed by logistic regression analysis, using frequency of tooth brushing on the age of 5 as possible confounding factor. CONCLUSION: In this group of children the use of fluoride tablets during the first 5 years of life does not seem to increase the prevalence of fluorosis.

Administration, Oral↗
PubMed1997

Progression of radiopacities and radiolucencies under amalgam restorations on bite-wing radiographs.

Radiolucent and radiopaque areas in the dentine under amalgam fillings represent demineralized tissue. The aim of this study was to investigate whether caries progresses in radiolucent and radiopaque areas under amalgam fillings, by assessing their enlargement longitudinally on bite-wing radiographs. Bite-wings from dentitions of persons aged 17, 20 and 23 years were compared. For a 3-year evaluation, 365 teeth with class I and class II amalgam restorations were available on bite-wings; 16 radiopacities, 46 radiolucencies and 28 combinations could be followed longitudinally. All radiopacities remained the same size, 14 radiolucencies enlarged and 8 combinations enlarged. For a 6-year evaluation, 236 filled teeth were available; 10 radiopacities, 30 radiolucencies and 11 combinations could be compared longitudinally. All radiopacities remained the same size, 12 radiolucencies enlarged and 6 combinations enlarged. Because the radiopaque areas had not enlarged visibly on bite-wing radiographs over 3 or even 6 years, it was concluded that radiopacities may be non-progressing caries. A substantial number of radiolucent areas, with or without concomitant radiopacities, did not enlarge while radiolucent areas are considered as progressing caries.

Adolescent↗
PubMed1997

Validity of radiographs for diagnosis of secondary caries in teeth with class II amalgam restorations in vitro.

In the present in vitro study, the validity was determined of bite-wing radiographs for the diagnosis of secondary caries in approximal parts of teeth with class II amalgam restorations in vitro. The study was performed on 47 molars and 49 premolars providing 68 and 69 filled approximal surfaces, respectively. The teeth were radiographed in a buccolingual direction to obtain images comparable to bite-wings. Radiolucencies and radio-opacities were scored as caries. Subsequently the teeth were sectioned (700 microns) in transverse or sagittal direction and then the sections were radiographed. Validation was performed against these radiographs of sections, on which also radiolucencies and radio-opacities were scored. Statistical analysis of the results revealed significant differences between the validity parameters for molars and premolars, being for sensitivity 73 and 80%, respectively, for specificity 90 and 95%, for positive predictive value 95 and 92%, and for negative predictive value 58 and 86%. For molars, the results did not differ significantly from the results of our previous study on caries diagnosis in teeth with occlusal fillings. The present experiment showed that bite-wing radiographs are useful for the diagnosis of secondary caries under approximal parts of class II amalgam restorations, just as for secondary caries diagnosis adjacent to class I restorations.

Bicuspid↗
PubMed1997

[Caries treatment strategy. 'Tip the balance'--drilling or not drilling].

Traditionally caries treatment strategy has been based on the detection of caries lesions, and directed to a restorative procedure whereby the detected defects were filled. However, the detection of lesions is not synonymous to caries diagnosis. The main purpose of caries diagnosis should be the determination of the caries activity. The diagnosis is based on several parameters, which are evaluated by an intellectual process in a dentally trained mind. The treatment should be confined, in the first instance, to stopping the caries process, and to tipping the balance in the right direction, so that the caries can cure or anyway is prevented from extending. The treatment philosophy has to be pointed to a general approach of the disease caries in the patient who it concerns on the one side, and to a local approach of individual lesions on the other hand. In the second case a lesion can be treated in a symptomatic, invasive manner or, even better, by causal, not-invasive treatment.

Child↗
PubMed1997

[Prevention of caries in children].

There is a stagnation in the previously ongoing improvement of the dental health of children. Therefore, an evaluation of the guidelines for dental care is necessary. Prevention should be based on an improvement of home care. It is advised to use a dentifrice with 500 to 750 ppm fluoride till the age of five. Professional applications in the dental office are most beneficial when early signs of decay are observed. Indications for professional applications are proposed.

Child↗
PubMed1997

[The new fight against mutant streptococci].

Mutans streptococci are an important factor in the aetiology of dental caries. New ways of combating these bacteria have become available with the development of molecular biological techniques. One of these strategies involves the genetic modification of mutans streptococci to develop less cariogenic mutants. Acid production and the production of intracellular polysaccharides have been eliminated. But it is not clear yet whether these less cariogenic mutant strains are able to replace the normal mutans streptococci in dental plaque. Immunization is another possibility to suppress mutans streptococci. Antibodies against proteins involved in adherence of mutans streptococci have been raised by active immunization. It is also possible to raise antibodies in cow serum and milk, in eggs of chickens and even in tobacco plants. After isolation, these antibodies are to be applied topically. In the future, these new strategies may prevent or reduce caries. However, further research is necessary to resolve the obstacles on the way to commercial application.

Antibodies, Bacterial↗
PubMed1996

Protection of bovine enamel and dentine by chlorhexidine and fluoride varnishes in a bacterial demineralization model.

In an in vitro demineralization model, the protective effect of two chlorhexidine varnishes, Cervitec (1% w/w chlorhexidine diacetate and 1% w/w thymol) and EC40 (40% w/w chlorhexidine diacetate), was compared with that of Fluor Protector, a varnish containing 0.1% w/w F. The demineralization model comprised an acidogenic Streptococcus mutans suspension in agarose placed on enamel or dentine specimens. The experiments extended over three serial 22-hour demineralization periods with fresh S. mutans suspensions for each period. To determine whether the varnishes released enough demineralization-inhibiting compounds, approximately 10 microliters of the varnishes was applied adjacent to the enamel and dentine specimens just before the first application of the S. mutans suspensions and left during the serial experiments (release study). In a separate series of experiments, the effect of the pretreatment of the enamal and dentine specimens with the various varnishes was tested (pretreatment study). In the release study the protective effect for enamel decreased in the order: EC40 = Fluor Protector >> Cervitec = no treatment. For dentine this order was: EC40 >> Fluor Protector = Cervitec > no treatment. In the pretreatment study, the enamel specimens were best protected by Fluor Protector (Fluor Protector >> Cervitec = EC40 > no treatment), while the dentine specimens were best protected by the chlorhexidine treatments (Cervitec = EC40 > Fluor Protector > no treatment). A 1:1 mixture of Cervitec and Fluor Protector was as effective as the most effective component alone. It is concluded that a varnish containing both fluoride and chlorhexidine may be useful, since it could give optimal protection to both enamel and dentine.

Animals↗