The effects of fluoride and chlorhexidine varnishes on the microflora of dental root surfaces and on the progression of root-surface caries were studied. Forty-four patients, surgically treated for advanced periodontal disease, were distributed at random among three groups. All patients received a standardized preventive treatment. Furthermore, the dentition of the patients in the two experimental groups was treated, at three-month intervals, with chlorhexidine and fluoride varnish, respectively. Patients in the control group received no additional treatment. In the experimental groups, plaque samples were collected from selected sound and carious root surfaces at baseline and at three, six, and nine months after the onset of the study. The presence of root-surface caries was scored at baseline and after one year. In addition, the texture, depth, and color of the root-surface lesions were monitored. Mutans streptococci on root surfaces were suppressed significantly (p less than 0.05) during the whole experimental period in the chlorhexidine varnish group, but not in the fluoride varnish group. A non-significant increase in the number of Actinomyces viscosus/naeslundii was noted after treatment with chlorhexidine and fluoride varnish. The increase in the number of decayed and filled root surfaces after one year was significantly lower in the experimental groups than in the control group. After treatment with chlorhexidine varnish, significantly more initial root-surface lesions had hardened than in the other groups.

For the isolation of Streptococcus mutans, several selective media have been developed, of which Mitis-Salivarius Sucrose Bacitracin agar (MSB) is the most widely used (Gold et al., 1973). Recently, the Trypticase Yeast-Extract Cystine agar medium (TYC, de Stoppelaar et al., 1967) was modified into a selective medium for S. mutans, called Trypticase Yeast-Extract Cystine Sucrose Bacitracin (TYCSB, van Palenstein Helderman et al., 1983). The aim of this study was to compare the recovery of S. mutans from clinical samples on Mitis-Salivarius agar (MS), MSB, TYC, and TYCSB. Further, a new simple selective medium for S. mutans was introduced. This medium, called TSY20B, was supposed to have the same qualities as TYCSB, but its preparation is less laborious. One hundred eighty-five plaque and saliva samples from 37 subjects were plated on MS, MSB, TYC, and TYCSB, and 285 samples from 23 subjects were plated on TYCSB and TSY20B. All plates were incubated at 37 degrees C in a 91% N2, 5% CO2, 4% H2 atmosphere for five days. The S. mutans counts on TYC and TYCSB were significantly higher than on MS or MSB by almost a factor of 10. Seventy-seven percent of the samples gave higher S. mutans counts on TYCSB than on MSB. Especially, samples with high S. mutans d/g numbers gave lower S. mutans counts on MSB. These data clearly indicate that MSB agar is inhibitory for S. mutans and should not be used. An additional advantage of TYCSB over MSB agar is the possibility of distinguishing S. mutans serotypes d/g from other serotypes.(ABSTRACT TRUNCATED AT 250 WORDS)

This study describes the effects of varnishes containing 0%, 10%, 20%, or 40% chlorhexidine diacetate on the microflora of human fissure dental plaque. Sandarac, a natural resin, was used as the varnish base. Ten subjects, each with at least four sound fissures harboring high levels of Streptococcus mutans, participated in the study. The fissures in each of the individuals were randomly assigned to four experimental groups, in each of which one of the varnishes was tested. The varnish treatment consisted of a single application of a small amount of varnish onto the fissures. Apart from the selected fissures, the rest of the dentition was left untreated. All chlorhexidine-containing varnishes selectively suppressed S. mutans in fissure plaque, and had no effect on total viable counts or on the numbers of Actinomyces viscosus/naeslundii and Streptococcus sanguis beyond one week. The extent of the suppression depended upon the concentration of chlorhexidine in the varnish, 40% chlorhexidine varnish giving the greatest suppression of S. mutans. At 22 weeks, after a single treatment with varnish containing 40% chlorhexidine, mean S. mutans counts were more than ten times lower than in the control or 10%-chlorhexidine varnish group. At that time, S. mutans was still undetectable in five out of ten experimental fissures in this group. The results suggested that sandarac varnishes containing high concentrations of chlorhexidine can be used successfully for long-term suppression of S. mutans in dental fissures.

A 3-year cohort study was carried out in 252 pre-school children for early identification of caries-active individuals. During this period information was collected about the acquisition of mutans streptococci and lactobacilli from the age of 2 till 5 years old. At baseline mutans streptococci were detected in 43% of the children while the detection frequency of lactobacilli was low (11.5%). On an individual level, numbers of colony-forming units of mutans streptococci and lactobacilli in plaque and saliva varied largely during the study period. The correlations between the numbers of lactobacilli and mutans streptococci in the saliva of the mother and the saliva and plaque of the child were low and never exceeded r = 0.22. Very low correlations (< r = 0.22) were also found between the numbers of mutans streptococci or lactobacilli and the diet in terms of the number of sugar intakes. Nevertheless, in children older than 2.5 years correlations between the clinical caries score and lactobacilli in saliva (range 0.31–0.62) and mutans streptococci in plaque or saliva (range 0.24–0.46) were highly significant (p < 0.01).

The objective of this study was to compare the performance in occlusal caries diagnosis of various available diagnostic systems when applied to the same teeth. The sample investigated consisted of 13 children for whom 4 premolar and 19 molar teeth were judged to require a sealant. The indication was based on the criteria ‘fissure discoloration’, ‘enamel decalcification’ and ‘absence of dentinal decay’. For predefined locations within these occlusal fissures a diagnosis was obtained by the following diagnostic systems: clinical examination, examination on fiber-optic transillumination (FOTI), fissure discoloration, electrical resistance measurement, radiographic examination and ratings of fissure morphology. Tooth material was removed until no (more) carious enamel or dentin was left. Two dentists then jointly decided on the status of decay for each of the defined locations within the fissure. These ratings served as the ‘gold standard’ diagnoses. The electrical resistance measurement with a sensitivity of 0.96 and a specificity of 0.71 was the only diagnostic tool with acceptable performance. Radiographic diagnosis was characterized by a moderate sensitivity and specificity. All other diagnostic systems had either very low sensitivities or very low specificities, or both. The positive predictive value of FOTI examination and the negative predictive value of the electrical resistance measurements were very high, irrespective of the prevalence of occlusal dentinal decay.