Disease activity and need for dental care in a capitation plan based on risk assessment.

This article describes a capitation model of care which would stimulate both dentists and patients to apply existing preventive knowledge.

The effect of monitored chlorhexidine gel treatment on mutans streptococci in margins of restorations.

OBJECTIVES: The objective of this study was to compare the effect of a monitored chlorhexidine (CHX) gel treatment with a conventional two-day CHX treatment in subjects with well-restored dentitions and high numbers of salivary mutans streptococci (MS). METHODS: In the test group (n = 8), the effect of the CHX gel applications was monitored in margins of restorations and in saliva during a period of 12 weeks. Strip Mutans was used for monitoring and whenever a sample revealed growth of MS, the subject received a 3 x 5 min 1% CHX gel treatment at the clinic. Nine subjects (control group) were only given the baseline (conventional) treatment with CHX gel 3 x 5 min on two consecutive days. RESULTS: The monitored treatment in the test group resulted in a more pronounced reduction of MS both in margins of restorations and in saliva than the conventional treatment. The difference between the level of MS in the margins in the two groups was, however, only significant at the 20-week examination. There was a large individual variation in the effect of the CHX treatment, and three to nine extra CHX gel applications were needed in the test group to keep MS below a detectable level during the 12 weeks. CONCLUSIONS: Our findings illustrate the difficulties to obtain a long-lasting reduction of MS in subjects with a large number of restorations and a high number of MS by antimicrobial treatment only. The results indicate the necessity to combine antimicrobial treatment with, for example, sucrose restriction, in order to keep MS at a low level for a longer period of time.

Serendipity or luck: stumbling on gingival crevicular fluid.

The word "serendipity" comes from the tale "The Three Princes from Serendip" by Horace Walpole. It is defined as an aptitude for making fortunate discoveries accidentally." The demonstration of crevicular fluid was truly an accidental discovery. Niels Brill, a successful private practitioner in Copenhagen with prosthodontics as a specialty, and Bo Krasse, associate professor of cariology, were examining the microflora of gingival pockets in a dog. Before the samples were taken, gingiva and teeth were disinfected with an iodine solution. The solution disappeared from different pockets at different speeds. After intravenous injection of a fluorescein solution, the occurrence of fluorescein could be recorded on filter paper strips. Thus, after stumbling on the disappearance of iodine from the cervical areas of the teeth, two non-periodontologists managed to demonstrate why it disappeared. This article describes the details of the discovery and subsequent studies, and offers some reflections by one of the original authors 37 years later.

From the art of filling teeth to the science of dental caries prevention: a personal review.

The journey from the art of filling teeth to the science of prevention is reviewed. First, a private winding road is described that produced some new methods of value in risk assessment, treatment of the causes of dental caries, and prevention of the disease. The description illustrates the importance of monitoring the effects of different measures. Next, the new knowledge and methods that form the primary basis of prevention on a large scale are reviewed. They represent a golden era in caries research and form a solid ground for the prevention of dental caries and for the treatment of the causes of disease. The prevalence and incidence of dental caries has fallen not only among schoolchildren, but also among adults in developed countries. Improvement in dental health is due to the successful application of new knowledge-it has not happened by chance. New or improved opportunities for prevention could lead to a further reduction in dental caries. The problem is to find ways to stimulate both dentists and patients to use them. Finally, the next part of the journey is discussed. In some countries the journey probably will be an uphill struggle; in others, it could be fairly undulating, eventually leading to further declines in dental caries.

Caries incidence, effect of preventive measures, and caries prediction in Uruguayan children.

In 1988, 100 12- to 13-year-old children from two neighborhoods in Montevideo with different standards of living were examined. Twenty-three children with large numbers of mutans streptococci, lactobacilli, or decayed surfaces or a combination of these factors were considered to be at high risk of developing caries. Twelve of these 23 children were selected for special preventive measures. A second examination was made 18 months later, at which 81 of the originally 100 children were studied. The clinical and microbiologic variables were tested for their ability to predict caries by calculating their sensitivity, specificity, the positive and negative predictive values. The incidence of new DMFS was significantly higher in the children from the low than in those from the high socioeconomic area. It was also significantly higher in the children considered being at high risk than in those at low risk at the start of the study. Preventive measures reduced the caries risk. The highest sensitivity was obtained with the clinical test, whereas the highest specificity was obtained with the combined clinical and microbiologic tests. The findings indicate that methods for identifying children at risk which started to be used in Scandinavia 20 years ago could be applied in the Uruguayan population of today. It is valuable to know this, as the resources for both treatment and prevention are very limited.

Dental caries and microbial and salivary conditions in Uruguayan children from two different socioeconomic areas.

Dental caries, microbial and salivary conditions, dietary habits, and socioeconomic conditions were studied in 100 12- to 13-year-old children from 2 different socioeconomic areas in Montevideo: Pocitos and Piedras Blancas. The residents of Pocitos had a higher educational level, better housing conditions, and occupations involving higher earnings than those of Piedras Blancas. The caries prevalence in the two areas was about the same, but the children in Piedras Blancas had more decayed surfaces and fewer filled surfaces than the children in Pocitos. The mean values for caries in Piedras Blancas and Pocitos were, DMFT, 4.2 and 4.2; DMFS, 8.1 and 7.8; DS, 4.7 and 2.5; and FS, 1.7 and 4.7, respectively. The differences in DS and FS were statistically significant. The frequency of sugar intake and the salivary secretion rate were similar, but the buffer capacity was significantly higher in Pocitos than in Piedras Blancas. The plaque index was the same, but the distribution of cariogenic microorganisms differed significantly. Fifty-eight per cent of the children in Piedras Blancas had more than 10(6) CFU of mutans streptococci per milliliter saliva, compared with 17% of the children in Pocitos. Similar differences were found with regard to the lactobacilli. The percentage of children with high numbers of mutans streptococci was higher in Piedras Blancas and lower in Pocitos than in previous epidemiologic studies in Scandinavia. It was, however, higher than that recently noted in Finland.

Effect of chlorhexidine treatment followed by stannous fluoride gel application on mutans streptococci in margins of restorations.

The effect of antimicrobial treatment on the numbers of mutans streptococci (MS) in plaque from margins of restorations and in saliva was studied. Nineteen persons with well-restored dentitions and > 0.5 x 10(6) MS per ml saliva were treated with 1% chlorhexidine (CHX) gel in individually designed applicators 5 min/day for 9 days. Ten of the subjects continued the treatment with 0.4% stannous fluoride (SnF2) gel and the remaining 9 with a placebo gel for another 14 days. Plaque samples from margins of selected restorations and stimulated saliva were collected at baseline, after the completion of each gel treatment and then again at regular intervals up to 24 weeks. The CHX gel treatment suppressed MS in the margins of restorations as well as in saliva. Additional treatment with the SnF2 gel prolonged this suppression compared with CHX treatment alone. In the CHX-SnF2 group, the number of MS in margins of amalgam and composite restorations was still significantly lower at the end of the study compared with the baseline. In the CHX placebo group, the margins of amalgam restorations, mainly placed in premolars and molars, were recolonized somewhat faster than the margins of composite restorations in the front teeth.

A simple method for monitoring mutans streptococci in margins of restorations.

Plaque material collected from margins of restorations using a sharp toothpick was streaked across one and the same plastic strip from a commercially available test kit and inoculated in a liquid medium containing bacitracin. The reproducibility of the method was good. The method is simple, inexpensive and suitable for the chairside demonstration of the colonization of mutans streptococci in localized areas of the mouth, such as margins of restorations.

Dietary habits and dental caries in a population of Spanish schoolchildren with low levels of caries experience.

The aim of this study was to analyze the relationship between current dietary habits and dental caries in schoolchildren from an area of Spain on which the prevalence of caries was low. The results of an epidemiological study conducted on a random sample of 893 children from the cities of Girona and Figueres are presented. The method of dietary interview consisted of a food-frequency questionnaire. This showed a positive relationship between dental caries and consumption of ice cream, pastries, cakes, sliced bread, on the one hand, and sugar-free chewing gum and sugar-free candies, on the other. A protective effect of skimmed milk and artificial sweeteners was also observed. Results reflect the role of certain foods in caries development, but also the outcome of selective dietary counseling to high-risk children.

Mutans streptococci in margins of fillings and crowns.

A significant correlation was found between the number of mutans streptococci in saliva and the proportional distribution of these microorganisms in pooled plaque from the margins of all restorations. At high salivary numbers there was a tendency towards a higher porportion of mutans streptococci in plaque from the margins of separate restorations. At low and medium salivary numbers, plaque samples could, however, contain greater than 10 per cent mutans streptococci and even less than 1 per cent was found in plaque from margins of restorations at high salivary numbers. The reproducibility of the plaque sampling method was good. Plaque material collected on different occasions from the same margins did not vary significantly in terms of proportions of mutans streptococci. The numbers of mutants streptococci in plaque samples from different restorations of the same kind collected on the same occasion in the same mouth could, however, show a considerable variation. The observations made in this study, indicate that a low salivary number of mutans streptococci does not exclude a high proportion of these microorganisms in plaque from the margins of separate restorations. This has to be considered when efforts are made to reduce the risk of recurrent decay.

Crevicular IgG antibodies and recovery of locally implanted Streptococcus mutans in humans.

This study was undertaken with the aim of examining the effect of highly different IgG antibody activities in gingival crevicular fluid (GCF) on the elimination of a streptomycin-resistant strain of Streptococcus mutans (S. mutans) topically implanted on the tooth. Two groups of people were selected for the study, one with high and one with low specific IgG antibody activity (IgG antibody activity against S. mutans) in GCF. During an experimental period of 15 d the specific IgG antibody activity in GCF in the same individual stayed on a relatively constant level. Between individuals, however, the specific IgG antibody activity varied considerably. The number of indigenous mutans streptococci and the number of implanted bacteria on the same tooth surface were strongly correlated. The implanted S. mutans strain was rapidly eliminated in all subjects. No difference in the elimination of the implanted strain of S. mutans could be demonstrated between the groups of high and low specific IgG antibody activity.

Dental caries and salivary and microbial conditions in 50-60-year-old persons.

In a group of 124 persons, 50-60 yr old, the prevalence at baseline of mutans streptococci (MS) and lactobacilli and the salivary secretion rate and buffer capacity were examined. The mean secretion rate was 1.58 mL/min with a flow rate below 1 mL/min found in 20% of the persons. A buffer capacity below end pH 5.5 was observed in 64% of the subjects. MS was not detected in 5% of the persons whereas 17% had 10(6) or more MS per ml saliva. Lactobacilli were not found in 10% of the persons while 21% had counts in excess of 10(5) CFU mL. A new examination 5 yr later in 1986 revealed no significant changes in secretion rate and buffer capacity or in the population of lactobacilli, whereas markedly elevated levels of salivary MS were found. S. sobrinus was detected in 35-37% of the persons at the two examinations. Persons with both S. mutans and S. sobrinus had more MS than persons with only S. mutans.

Crevicular IgG antibodies and Streptococcus mutans on erupting human first permanent molars.

The specific IgG antibody activity against indigenous Streptococcus mutans in gingival crevicular fluid (GCF) was determined in 25, 6-7-yr-old children. Samples of plaque and GCF were collected from all erupting first permanent molars. Plaque samples were also collected from the adjacent second primary molars. The presence of clinical caries was scored as defs. In the same individual a highly significant correlation (p less than 0.005) was found between the level of specific antibody activity in GCF when comparing first permanent molars with each other. No correlation was found between the specific antibody activity in GCF and the number of indigenous Strep. mutans colonizing the buccal surfaces of the first permanent molars. Caries-free children had significantly less specific antibody activity in GCF than children with caries experience (p less than 0.05). In the same child a highly significant correlation (p less than 0.0001) was found between the level of colonization by mutans streptococci on the permanent molars and the adjacent second primary molars.

Human strains of mutans streptococci show different cariogenic potential in the hamster model.

The cariogenic potential of fresh humans strains of Streptococcus mutans and Streptococcus sobrinus was examined in hamsters maintained on a high sucrose diet. The strains 1B 16 (S. mutans) and B13 (S. sobrinus) isolated 20-25 yrs ago served as positive controls. Three series of experiments were run. Some strains were tested once and some strains were tested in all 3 experiments. The animals infected with S. sobrinus strains generally showed lower caries scores than those infected with S. mutans strains. Among the groups infected with the different strains of S. mutans the caries scores varied. In one of the experiments the caries score of the animals infected with one of the Icelandic S. mutans strains was significantly higher than that of the positive control group and the group infected with one of the fresh Swedish isolates. Thus, different strains of mutans streptococci where shown to induce varying caries activity in the hamster model.