Xylitol in toothpaste: is it effective in reducing the levels of Streptococcus mutans in high caries risk young children?

Abstract

Design

This study is an observational prospective longitudinal cohort study, following 102 children aged 1 to 12 months over a period of 24 months. At baseline, a dental examination was carried out to assess the number of carious lesions present using the ICDAS system, and a saliva sample was taken to assess the levels of Streptococcus mutans (SM) in saliva using the Dentocult SM saliva strip. Cohort caregivers received toothbrushing instruction and a 25% xylitol toothpaste tube for which they were instructed to use twice a day over a 3-month period, after which they returned to clinic at Pristina University to receive another tube. This process continued throughout the entire 24-month study period. At the end of the study, SM prevalence was recorded again.

Cohort selection

102 children and their mothers were included in this study: 43 girls and 59 boys. At the beginning of the study, the child’s mean age was 6.7 months, and at the end, 30.8 months. A random sample of 60 mothers was selected to analyse SM levels.

Data analysis

The data set was summarised descriptively using summary statistics, percentages and statistical tests. Values were expressed as a mean and standard deviation. SM prevalence comparison between baseline and endpoint was tested using chi-square statistics.

Results

At the baseline dental examination, the child’s mean age was 6.7 (±3.7 months). At this point 59% of the 102 infants were edentulous. Caries was reported to be present in 12.4% of children. The mean ICDAS score was calculated as 0.70 (2.42 SD). When caries was present (87.6% of the 102 children included in the study), the majority of the caries experience (74.2%) was determined as at an early stage (ICAS score 1 or 2).

72.6% (n = 74/102) of children were infected with SM at baseline. 28 children had Level 1 (0) SM. 57 children had Level 2 and 3 (102-4) SM. 17 children had Level 4 SM (≥105) SM. The SM categorical distribution was statistically significant (p = 0.02).

At endpoint, 53.5% (57/102) of children were SM infected. Parallel comparison of pre- and post-data sets show that there was a 19.1% reduction in SM levels overall following the introduction of the xylitol toothpaste. (p = 0.002). In the participant group with the highest SM level (Level 4), a net 12.2% reduction in SM prevalence occurred. The change in SM infection was deemed statistically significant.

Conclusions

Brushing twice a day with toothpaste containing 25% xylitol shows a statistically significant decrease in SM levels. This shows a promising anticariogenic effect. Late SM colonisation is protective for future carious lesions. Xylitol can help prevent early childhood caries and early SM contamination.

A Commentary on

Latifi-Xhemajli B, Kutllovci T, Begzati A, Rexhepi A, Ahmeti D.

A prospective longitudinal cohort study of the effectiveness of 25% xylitol toothpaste on mutans streptococci in high caries-risk young children. Eur J Paediatr Dent 2023; 24: 188–193.

GRADE rating:

Commentary

Early childhood caries (ECC) is defined as caries affecting primary teeth in children under the age of five years old¹. In the UK, the prevalence of ECC is 41.0% in Wales, 33.0% in Scotland and 27.9% in England².

An observational study design examines the effect of an intervention, without manipulation of who is exposed to the intervention³. In this case, all participants were exposed to the intervention. There was no control group for this study, making it difficult to interpret whether confounding factors influenced the results. The paper stated that a small sample size of 102 mother-infant dyads participated in the study, despite the abstract mentioning that a total of 270 dyads initially participated. This implies a sample attrition of 168 dyads, the reasoning for this reduction was not investigated nor was the sample attrition mentioned in the main body of the paper. The paper briefly mentioned that children were recruited from a previous randomised controlled trial (RCT), but whether this introduced bias was not discussed.

This study was poorly standardised, with no consideration for the behaviours of the participants outside of the confines of the study such as dietary changes, use of other oral products, or dental appointment attendance within the 24 months they were observed. Contents of the 25% xylitol toothpaste were not discussed, leaving it questionable as to whether another ingredient in the toothpaste could have been a causal factor. It would have been pertinent to investigate the side effects of xylitol in the study, given the discussion of diarrhoea being a limitation to xylitol use in children in previous studies. There was no data collection regarding toothbrushing habits pre-intervention, hence it is debatable whether the results are due to the xylitol toothpaste use or a change in oral hygiene habits. Frequency and quality of toothbrushing were not monitored during the 24-month period and mothers were given limited instructions on toothbrushing, risking it being nonstandard amongst participants.

The authors decided to collect further data on initial dental caries prevalence, family socio-economic status and maternal level of SM infection. The abstract mentions that at baseline a dental examination was completed to assess early signs of caries using the ICDAS system, and that a maternal socio-economic questionnaire was administered by a dentist, neither methodologies were mentioned in the paper other than in the abstract. The results for both the baseline dental examination and socio-economic questionnaire were stated in the paper, however neither were further discussed. The paper stated that the maternal level of SM infection was randomly collected from 60 mothers, despite not mentioning how, when, or why 60 mothers were chosen out of the 102 participants. The results of the maternal level of SM infection are not stated in the paper. It is unusual practice for authors to omit results, to not discuss results included in the paper and to include information in the abstract that is not mentioned in the body of the paper.

The study was poorly written and designed which has detracted from both the novelty and potential for xylitol to be used in toothpaste to reduce SM levels and hence reduce caries prevalence, particularly in young children. Overall, further research will need to be conducted to validate the conclusions made in this study.

Practice points

• Clinicians should have an awareness of promising future caries prevention methods and potential alternatives to fluoride toothpaste.

• The results of this study need to be validated through further research, preferably with a stronger study design such as a RCT.