Birgitta Köhler

The effect of caries-preventive measures in mothers on dental caries and the oral presence of the bacteria Streptococcus mutans and lactobacilli in their children.

Seventy-seven first-time mothers were selected on the basis of high salivary counts of Strep. mutans [greater than 10(6) c.f.u. (colony forming units) per ml saliva]; 40 mothers were in the control group and 37 in the test group. Their infants were 3-8 months of age at the start of the study. A prophylactic programme for the test mothers, aiming at a reduction of Strep. mutans, was repeated at intervals of 2-4 months as and when necessary until their children were 3 years old. The test mothers as a group showed approx. 10-fold fewer Strep. mutans during the test period. At the age of 3 years, 70 per cent of the children in the control group carried Strep. mutans, compared with 41 per cent in the test group (p less than 0.01). Fifty-two per cent of the children who carried Strep. mutans had caries at this age, compared to 3 per cent of the children without this organism. The time when Strep. mutans was first detected in the children seemed to influence subsequent development of caries because 77 per cent of the children who carried Strep. mutans at the age of 15 months had caries at the age of 3 years. Approximately 40 per cent of the children in both the control and the test group had detectable lactobacilli in their saliva at 3 years. In general, the children in the control group had more lactobacilli.(ABSTRACT TRUNCATED AT 250 WORDS)

Streptococcus mutans serotypes: some aspects of their identification, distribution, antigenic shifts, and relationship to caries.

For an immunologic point of view, several facts are worth consideration. S mutans can be separated into at least seven serotypes. Five of the types are based on antigens that may be specific for S mutans. One type, e, is related to the Lancefield group E streptocci, and one type, f, may lack an antigen that shows serological specificity. Analyses of plaque samples from individuals with a high caries activity have, in most instances, shown the presence of c, d, and possibly the g types. This does not necessarily mean that they are per se more cariogenic than the other types, but if all the serotypes cannot be combatted simultaneously, the c, d, and g types are an obvious first choice. S mutans strains do have antigens other than those used for serological identification, and it is not known which antigens can evoke antibodies with the highest protective capacity in humans. The phenomenon of antigenic shifts may make it possible for the bacteria to elude antibodies. However, the number of possible changes may be restricted. If certain antigens are of importance for the cariogenicity of S mutans, a change in their structure might result in a less cariogenic flora.

A 3-YEAR CLINICAL EVALUATION OF TWO COMPOSITE RESINS IN CLASS-II CAVITIES

The purpose of this investigation was to study the clinical performance of a new system with a proposed expanding liner for composite restorations introduced in the late 1980s. The present study reports on baseline data and the result after 3 years. One hundred and four class-II cavities in 95 patients were alternatively restored by Superlux Molar and the reference material P-50 APC by 12 general practitioners in 3 public dental health clinics. After 3 years 82 restorations (79%) were available for examination. The restorations were evaluated on the basis of USPHS criteria after 1 week and again after 3 years. Stone casts were used to quantitatively categorize wear in accordance with the Leinfelder method. Color slides and bitewings were taken to supplement the clinical evaluation of color match and marginal adaptation, respectively, and secondary caries. The failure rate (USPHS rating, Charlie) was four restorations of Superlux Molar and seven of P-50 APC. The average wear after 3 years of Superlux Molar was 131 microm and of P-50 APC, 128 microm. There were no statistically significant differences between the two materials with regard to, for example, handling characteristics, anatomic form, color match, marginal discoloration, or failures. A significantly higher wear rate was found after 3 years in patients with a high level of salivary lactobacilli (> 10(5) colony-forming units (CFU)/mL at base line) compared with those with lower levels. This suggests that an acidic environment might enhance the wear rate.

Immunofluorescent determination of the relative proportions of Streptococcus mutans in human dental plaque: a comparison with cultural techniques.

Abstract The relative proportions of Strep. mutans were determined by direct cell counts in sonified plaque smears treated with fluorescein-isothiocyanate labelled antisera against Strep. mutans . In parallel, the plaque samples were cultivated on blood agar plates, mitis-salivarius and MC agar plates. The mean percentage of Strep. mutans in 36 samples was 7.3 per cent as determined by immunofluorescence and 6.1 per cent by cultural methods. The determinations with immunofluorescence showed an overall linear relationship with those obtained by culturing on mitis-salivarius agar. Compared with MC agar, a few samples showed considerably higher values in fluorescence.