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.

Preventive measures in mothers influence the establishment of the bacterium Streptococcus mutans in their infants.

First-time mothers who had a high salivary number of Strep. mutans [greater than or equal to 10(6) colony-forming-units (c.f.u.) per ml] were selected. Every second mother was given a special preventive programme to reduce her salivary level below 3 x 10(5) c.f.u. per ml. Where a reduction of Strep. mutans was achieved in the mother, the establishment of Strep. mutans in her infant was prevented or delayed. Thus, 28 mothers were successfully treated until their infants were 23 months old and only 3 of their infants (11 per cent) were infected with Strep. mutans, compared with 17 out of 38 infants in the control group (45 per cent). In both groups, the percentage of infected infants increased with increasing age, although at all ages fewer infants were infected with Strep. mutans in the test group than in the control group. Sixteen infants of successfully treated mothers had reached the age of 36 months. Three were infected (19 per cent) compared with 17 out of 27 in the control group (63 per cent). These findings show that the spread of Strep. mutans can be delayed or prevented by measures directed against the main source of infection, an approach which is successful in the prevention of other infectious diseases.

The relationship between IgA antibodies to Streptococcus mutans antigens in human saliva and breast milk and the numbers of indigenous oral Streptococcus mutans.

The influence of indigenous Streptococcus mutans on naturally-occurring levels of IgA antibodies was studied in 42 lactating females. Breast milk, parotid and whole-saliva samples were collected and analysed by the ELISA method for IgA antibodies, reacting with antigens from Strep. mutans. All salivas and breast milk showed IgA antibody activity to five antigenic preparations from Strep. mutans and to a pool of Escherichia coli antigens. No correlation was observed between the IgA antibody level in breast milk and that in saliva. The total IgA in breast milk was, however, considerably higher than in the salivas. In subjects with active caries and subjects with high DMFS scores, there was a tendency toward lower levels of IgA antibodies in whole saliva than in subjects with low caries experience. The levels of specific IgA antibodies in saliva did not reflect the amount of indigenous Strep. mutans present in the mouth at the time of sampling.

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.

Effect of caries preventive measures in children highly infected with the bacterium Streptococcus mutans.

The number of Strep. mutans in saliva samples was examined in 101 13-14-year-old children, 53 in a control and 48 in the test group. All in the test group with 2.5 X 10(5) Strep. mutans per ml saliva were treated with 1 per cent chlorhexidine gel, once a day, for 14 days when the number of Strep. mutans was greatly reduced. Saliva samples were then examined in the test group every 4th month and all children with Strep. mutans levels above 2.5 X 10(5) were treated. A few selected children had fissure sealants applied to the occlusal surfaces. After 3 years, the mean number of new carious lesions was 9.6 in the control group and 4.2 in the test group. In the children with 10(6) Strep. mutans at the start of the study, the corresponding figures were 20.8 compared with 3.9. Thus a reduction in caries activity can be achieved by controlled antimicrobial treatment.

Antibodies reacting with Streptococcus mutans in secretions from minor salivary glands in humans.

1) Antibodies reacting with S. mutans in secretions from minor salivary glands in humans were determined by a modified Enzyme Linked Immunosorbent Assay. 2) IgA antibodies reacting with S. mutans serotype c were found in all samples examined. 3) The antibody level in the secretions of the minor salivary glands varied considerably between different subjects and was considerably higher than that of parotid saliva. 4) A variation in antibody concentration over time was observed in some individuals. 5) Topical application of a streptococcal vaccine consisting of formalin killed cells increased the level of antibodies in the secretions of one person. In two persons no effect was observed.

Dental health education by "barefoot doctors".

In an insurance company 18 out of 507 employees were trained as dental health educators. They then informed their fellow workers about prevention of caries and periodontal disease in groups of about 10 persons. Two information meetings were held during a period of 10 months. Eighty-nine percent of the employees were positive to this educational programme. Twenty-two percent said that they had reduced the intake of sucrose after the first meeting. Even more persons reduced their sucrose intake later. Saliva secretion rate and buffer capacity were analyzed and the number of lactobacilli and Streptococcus mutans were determined before and after the information meetings. A significant reduction in the number of lactobacilli was found, confirming the change in carbohydrate intake. The information raised the level of knowledge about dental health among the employees. It was suggested that this type of educational programme should be used in other health areas.

Streptococcus mutans, lactobacilli and dental health in 13-14-year-old Swedish children.

The dental health and the prevalence of Streptococcus mutans and lactobacilli were examined in 101 13-114-year-old children. The average number of decayed (incipient caries) and filled surfaces (DFS) was 10.1 and 12.8, respectively. S. mutans was not detected in 11% of the children while 21% had 10(6) or more S. mutans per ml saliva. Lactobacilli were not found in 21% of the children whereas 11% had 10(5) or more lactobacilli per ml saliva. Statistically significant correlations were found between S. mutans and lactobacilli, S. mutans and DFS, lactobacilli and DFS and S. mutans plus lactobacilli and DFS. Increasing numbers of S. mutans and lactobacilli, alone and in combination, were associated with an increased caries frequency.

Microbial conditions and caries increment 2 years after discontinuation of controlled antimicrobial measures in Swedish teenagers.

The purpose of the present study was to examine the long-term effect of a special caries preventive program in teenagers. Over a 3-yr period directed and controlled antimicrobial treatment using Streptococcus mutans as an indicator organism resulted in a remarkable caries reduction especially in children with greater than 10(6) S. mutans per ml of saliva at the start of the study. Two years after discontinuation of the special preventive program 83 out of 101 subjects, 18-19 yr old, were reexamined. All the children had followed the same basic preventive program in the Dental Health Service. The number of S. mutans and lactobacilli per ml of saliva within and between control and test groups was with few exceptions practically the same as 5 yr earlier. During the posttreatment period the caries activity was similar in the control and test groups and lower than during the experimental years especially in the control group. Subjects with initial S. mutans level of greater than 10(6) CFU per ml of saliva continued to show incremental caries scores higher than those subjects with lower S. mutans levels.

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.

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.

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.

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.

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.

Asymmetrical dental caries and Streptococcus mutans infection.

A 27-year-old woman chewed unilaterally and had restorations and caries only on the right side of the dentition. The left side had a greater amount of soft and hard deposits and more severe periodontal disease. Plaque samples from occlusal and interproximal tooth surfaces were collected and cultured. The proportion of Streptococcus mutans of the total anaerobic count in the plaque samples from the right side was 1,000 to 10,000 times as high as from the left side. The proportion of S mutans of the total streptococcus was 6% to 20% on the right and less than 1% on the left side.

The cariogenic potential of foods--a critical review of current methods.

Current methods used in examining the cariogenic potential of foods are plaque pH measurements, measurements of adhesiveness of foods, experimental caries models and animal tests. pH measurements can be used for separating the non-acidogenic foods from the acidogenic ones but they are not suitable for separating foods with different levels of caries inducing potential. This is illustrated by the fact that virtually all foods which contain carbohydrates cause the pH of human plaque to fall below 5.5. Cooked rice and beans also give such a pH drop but these foods have a very low caries-inducing potential, as shown in studies of persons with hereditary fructose intolerance. Furthermore, experimentation has shown that acid formation and enamel dissolution are not directly correlated. Animal models exist in which various test foods can be examined under identical conditions. By using the same microbial challenge and a reference food, for example sucrose, the relative cariogenic potential of a test food can be calculated. One limitation with these animal models is that the foods have to be given in powdered form and not in the physical form in which they are consumed by humans. The main objection against most of the current methods is that they reflect important factors in our concept of the pathogenesis of dental caries only to a limited extent. For example, only the animal tests can be used to illustrate the extent to which foods support the colonization of S. mutans on teeth. The qualitative composition of the plaque is practically never considered. A series of tests can, however, be combined to give more relevant information about the caries-inducing potential of foods.(ABSTRACT TRUNCATED AT 250 WORDS)

Biological factors as indicators of future caries.

During the last ten years the principal biological factors which have been used as indicators of future caries activity are counts of mutans streptococci and lactobacilli. The evidence that these micro-organisms play a key role in the development of dental caries has now become very strong. Methods for the identification and enumeration of mutans streptococci and lactobacilli in saliva and plaque material have been developed which are both feasible and reliable. In a few studies counts of these micro-organisms together with other factors have been related to caries incidence. The validity of the various tests show a large variation but in some studies the predictive value has been high. The best prediction of future caries activity is obtained by the combination of factors which are important contributors to the pathogenesis of dental caries.

Oral effect of other carbohydrates.

Historical data, epidemiological surveys, laboratory and animal experiments, clinical studies and observations in ordinary dental practice all illustrate that starchy fibrous foods have a low cariogenic potential. The recommended substitution of sucrose in Western diets by starchy foods would lead to a reduction of caries provided that these other carbohydrates replace the between meal consumption of sugar-rich products. The low cariogenic potential of a diet containing carbohydrates with a fibrous character is probably not solely due to its low sucrose content. Such a diet promotes mastication and saliva secretion which tend to reduce the caries risk. Furthermore, unrefined foods may contain caries-protective substances like phytates, trace elements and antibacterial factors. Lectins, which are found in many plants could be of importance by influencing the attachment of micro-organisms to the teeth in a favourable manner. The tradition to end a meal with fruit may thus have other oral effects than hitherto considered. In addition, a diet containing carbohydrates with a fibrous character and a low amount of sucrose probably has a low pathogenic potential for the periodontal tissues. However, no epidemiological data are available to support this assumption.

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.