Inger Sjöström

Effect of Long-Term Consumption of Milk Supplemented with Probiotic Lactobacilli and Fluoride on Dental Caries and General Health in Preschool Children: A Cluster-Randomized Study

The aim of this study was to evaluate the effect of milk supplemented with probiotic bacteria and fluoride on caries development and general health in preschool children. Children 1–5 years of age (n = 248) attending 14 day care centres with 27 units in northern Sweden entered the study. The centres were randomly assigned to two parallel groups: children in the intervention group were served 150 ml milk supplemented with Lactobacillus rhamnosus LB21 (107 CFU/ml) and 2.5 mg fluoride per litre for lunch while the control group received standard milk. The double-blind intervention lasted for 21 months (weekdays) and data were collected through clinical examinations and questionnaires. The primary outcome was caries increment and secondary outcomes were measures of general health. The dropout rate was 25%. The mean baseline caries experience was 0.5 dmfs in the intervention units and 0.6 in the control units and after 21 months 0.9 and 2.2 (p < 0.05). The number of days with sick leave was similar in both groups but the children of the intervention units displayed 60% fewer days with antibiotic therapy (mean 1.9 vs. 4.7 days) and 50% less days with otitis media (0.5 vs. 1.0) (p > 0.05). In children who had participated during the whole 21-month intervention, fewer days with otitis media were reported (0.4 vs. 1.3 days, p < 0.05). No serious side effects were reported. It is concluded that daily consumption of milk containing probiotic bacteria and fluoride reduced caries in preschool children with a prevented fraction of 75%. Additional beneficial health effects were evident.

Sugar fermentation in probiotic bacteria – an in vitro study

INTRODUCTION Food supplemented with probiotic bacteria is a rapidly growing sector of the market. The aim of the present study was to evaluate and compare the acid production of selected probiotic strains available in commercial products. METHODS Six Lactobacillus strains (Lactobacillus plantarum 299v and 931; Lactobacillus rhamnosus GG and LB21; Lactobacillus paracasei subsp. paracasei F19, and Lactobacillus reuteri PTA 5289) were cultivated at 37 degrees C in an anaerobic atmosphere on Man, Rogosa, Shape (MRS) agar for 48 h or MRS broth for 16 h. After centrifugation, the cells were washed and resuspended in sterile phosphate-buffered saline and immediately subjected to a fermentation assay with 12 different carbohydrates (nine sugars and three sugar alcohols) in microtiter plates with a pH indicator. The plates were examined for color changes after 24, 48, and 72 h of incubation under aerobic and anaerobic conditions. Three scores were used: negative (pH > 6.8); weak (pH 5.2-6.8), and positive (pH < 5.2). The strains were characterized with the API 50 CH system to confirm their identity. RESULTS L. plantarum fermented all the sugars except for melibiose, raffinose, and xylitol. Both L. rhamnosus strains were generally less active although L. rhamnosus GG was slightly more active than strain LB21 in the 5% CO(2) setting. The latter strain exhibited negative reactions for sucrose, maltose, arabinose, and sorbitol under anaerobic conditions. The assays with L. paracasei and L. reuteri had negative or weak reactions for all tested sugars under both aerobic and anaerobic conditions. CONCLUSION The metabolic capacity to form acid from dietary sugars differed significantly between the various probiotic strains.

Xylitol Concentration in Saliva and Dental Plaque after Use of Various Xylitol-Containing Products

The study consisted of two sets of experiments, one in saliva and one in dental plaque. The xylitol concentration in saliva was determined enzymatically in 12 children (mean age 11.5 years) after a standardised use of various xylitol products: (A) chewing gums (1.3 g xylitol), (B) sucking tablets (0.8 g xylitol), (C) candy tablets (1.1 g xylitol), (D) toothpaste (0.1 g xylitol), (E) rinse (1.0 g xylitol), and (F) a non-xylitol paraffin. Unstimulated saliva was sampled 1, 3, 8, 16 and 30 min after use. The concentration in dental plaque was determined after mouthrinses with contrasting amounts of xylitol (LX = 2.0 g, HX = 6.0 g, and control) and supragingival plaque was collected and pooled after 5, 15 and 30 min. The mean xylitol concentration in saliva at baseline was ≈0.1 mg/ml. All xylitol-containing products resulted in significantly increased levels (p < 0.05) immediately after intake and remained elevated for 8–16 min in the different groups. The highest mean value in saliva was obtained immediately after use of chewing gums (33.7 ± 16.4 mg/ml) and the lowest was demonstrated after using toothpaste (8.2 ± 4.9 mg/ml). No significant differences were demonstrated between chewing gums (A), sucking tablets (B), candy (C) and rinses (E). In dental plaque, the mean values were 8.6 ± 5.4 and 5.1 ± 4.0 mg/ml 5 min after HX and LX rinses. Concerning the higher concentration, the values remained significantly elevated (p < 0.05) during the entire 30-min follow-up. In conclusion, commonly advocated xylitol-containing products gave elevated concentrations of xylitol in unstimulated whole saliva and dental plaque for at least 8 min after intake.

Effect of xylitol-containing chewing gums on interdental plaque-pH in habitual xylitol consumers

Objective. The aim was to investigate the effect of high and low amounts of xylitol on the interdental plaque-pH, directly and after sucrose challenge, in schoolchildren with habitual consumption. Material and methods. The study group consisted of 11 healthy children (10–15 years) with low caries risk and the experiment had a single-blind crossover (Latin square) design. After a 2-week run-in period with a daily 4.0 g xylitol intake, the children were subjected to single-dose exposures of chewing gums with (i) paraffin (CTR; no xylitol), (ii) low-dose xylitol (LX; 2.0 g xylitol), and (iii) high-dose xylitol (HX; 6.0 g xylitol) in a randomized order separated by a washout period of 1 week. Samples of chewing-stimulated whole saliva were collected prior to and after the experimental period for determination of bacterial counts. The outcome measures were in situ plaque-pH (micro-touch method) and area under the pH curve (AUC). Results. The AUC was significantly greater (p<0.05) in the HX group compared to the LX and control groups during the first 5 min after chewing. After a 10% sucrose rinse, the interdental plaque-pH dropped in all groups but the HX regimen displayed significantly less reduction 0–5 min after chewing (p<0.05). No significant alterations of the total viable counts or mutans streptococci levels in saliva were disclosed during the 4-week experimental period. Conclusions. The present results suggested that a high single dose of xylitol had a short and limited beneficial effect on interdental plaque-pH in habitual xylitol consumers, while a low single dose, resembling normal chewing gum use, did not differ from the control.

Influence of a low xylitol-dose on mutans streptococci colonisation and caries development in preschool children

Aim: To evaluate the effect of xylitol-containing tablets on mutans streptococci colonisation and caries development in preschool children. Study design: Randomised single-blind prospective design. Methods: The material consisted of 132 healthy 2-year-old children, 71 boys and 61 girls and they were assigned to a xylitol tablet (test) group or a non-intervention control group. The mean age was 2 years + 1 month in both groups. The drop-out rate was 10.6% during the 2-year trial. The test group was given 1`-2 xylitol tablets (0.5`-1 g) per day during 1.5 years. Mutans streptococci (MS) enumeration was performed at baseline and semi-annually in the children and at baseline or shortly after in the mothers with a chair-side technique. Caries prevalence was scored at baseline and the age of 4 years. Results: No statistically significant differences in MS colonisation were disclosed between the test and control groups at baseline or any of the designated follow-ups. A statistically significant positive relationship was found between the maternal salivary MS levels and the colonisation of the children in the control group at 2.5 years, 3 years and 3.5 years (r=0.39, r=0.35; r=0.30; p<0.01, p<0.01 and p<0.05) but not in the xylitol tablet group (p>0.05). The mean caries prevalence was lower in the test group compared with the control group at 4 years of age (dmfs 0.38 ±1.05 vs. 0.80 ±2.60) but the difference was not statistically significant. Conclusion: The findings do not support a low-dose xylitol tablet program for caries prevention in preschool children.

Fluoride concentration in saliva after consumption of a dinner meal prepared with fluoridated salt.

The aim was to determine the fluoride concentration in saliva after intake of a dinner meal prepared with fluoridated salt. The investigation had a randomized cross-over design, and 10 healthy adolescents with natural fluoride content (1.06 ppm) in their drinking water participated after informed consent. After a run-in week, the subjects were served a standardized dinner of spaghetti with minced meat sauce prepared with either fluoridated salt (test arm) or non-fluoridated salt (control arm). The fluoride concentration of the test salt was 250 ppm. Samples of stimulated whole saliva was collected at baseline, directly after eating (0 min) and then after 10, 30 and 180 min. After a 1-week wash-out period, the experimental procedure was repeated with the opposite salt. Fluoride concentration in saliva was measured with a fluoride-specific electrode and the post-ingestion levels were compared with baseline using repeated-measures ANOVA.The mean baseline concentrations were 10.9 and 8.0 µg/l in the test and control arms, respectively. Immediately after the intake, the mean fluoride values increased significantly to 81.6 µg/l in the test arm and to 31.5 µg/l in the control arm (p < 0.05). The fluoride levels remained elevated (p < 0.05) for 30 min after ingestion of the test meal but not following the control meal. In conclusion, consumption of a dinner meal prepared with fluoridated salt increased the salivary fluoride levels for about 30 min.

Saliva profiles in children using heart failure medication: a pilot study

AIM: To study the saliva profiles in children with severe heart disease taking heart failure medication compared with the saliva from healthy age and gender matched controls. STUDY DESIGN: Cross sectional case-control design. METHODS: Twenty-four age and gender matched pairs of children, mean age 12.0 years participated. Stimulated saliva was collected in a standardized way before lunchtime and the subjects were asked to refrain from all eating, drinking and tooth brushing 90 mins before sampling. Stimulated salivary secretion rate, buffering capacity, total salivary viable count of bacteria, mutans streptococci and lactobacilli, calcium, chloride, magnesium, potassium, sodium and salivary IgA were determined. RESULTS: There were 7 of the 24 children in the cardiac group who had secretions below 0.5 ml/min compared with no child in the control group (p<0.01). Lower than 106 total viable counts of bacteria (TVC) were detected in the cardiac group 1.4×106 ± 1.2×107 vs. 2.7×106 ± 2.9×107 in the control group (p<0.05). Mutans streptococci (MS) in the cardiac group were 5.2×104 ± 1.5×105 vs. 8.1 ×103 ± 1.3×104 in the control group, (p>0.05) and MS ratio of TVC constituted 0.11±0.35 per cent compared to 0.01±0.02 per cent for the control group (p>0.05). STATISTICS: Continuous data were analysed by an analysis of variance (ANOVA) and categorical data by chi-square test. CONCLUSION: Reduced salivary secretion could be a caries risk factor in children taking heart failure medication.

Composition of the salivary microflora during habitual consumption of fluoridated milk

The aim was to evaluate the effect of habitual consumption of fluoridated milk on the composition of the salivary microflora. The study group comprised 20 healthy schoolchildren and young adults with a mean age of 13.6 years and the investigation had a randomized double-blind crossover design with a washout period of 1 month. After professional tooth-cleaning at baseline, the subjects were supplied with either fluoridated (250 mL, 5 ppm F) or non-fluoridated milk for one daily intake during a period of 4 weeks. Salivary samples were collected immediately before tooth-cleaning and after 1, 2, and 4 weeks, respectively. The samples were immediately cultivated for total viable counts, oral streptococci, mutans streptococci, lactobacilli, and actinomyces spp. Bacterial counts were logarithmically transformed before statistical evaluation using ANOVA. No significant alterations of the salivary microflora were found during any of the milk regimens compared with baseline. There was a slight reduction in the proportion of mutans streptococci after 2 and 4 weeks during consumption with fluoridated milk but the difference failed to reach statistical significance. In conclusion, this study was unable to disclose any significant alteration of the composition of the salivary microflora following daily intake of fluoridated milk.