Thorild 2003.

Methods	Randomised controlled trial (multi‐arm trial, with 3 arms)
Participants	173 women (new mothers) and their infants were randomised (116 to the groups included in this review). Inclusion criteria: healthy mothers with high counts of salivary mutans streptococci (MS) (> 150 CFU) and their three‐month old infants residing in the study area Exclusion criteria: not reported Setting: city of Varberg, a mid‐sized community in south‐west Sweden Important health characteristics of mothers reported: included women had high counts of salivary mutans streptococci at 3 months postpartum, otherwise healthy.
Interventions	Group 1: xylitol gum (n = 61 randomised) Women received gum containing 650 mg xylitol (Xylitol, Leaf, Finland), total weight/gum 1050 mg; requested to chew three pieces/day, for five minutes, in the morning, at noon, and in the evening. Group 2: chlorhexidine/xylitol gum (n = 55 randomised) Women received gum containing 532.5 mg xylitol, 5.0 mg chlorhexidine, and 141.9 mg sodium fluoride for a total weight/gum 1120.1 mg; they were requested to chew three pieces daily for five minutes, in the morning, at noon and in the evening. Group 3: sodium fluoride/xylitol gum (n = 57 randomised) Women received gum containing 288.5 mg xylitol, 188.8 mg sorbitol and 0.55 mg sodium fluoride, total weight/gum 870 mg; they were requested to chew 3 pieces daily, for five minutes, in the morning, at noon and in the evening. Intervention timing: intervention delivered 6 though 18 months postpartum (> 6 months intervention duration) Theory or model used as a basis for intervention: not reported
Outcomes	Data in meta‐analysis for: primary outcome: caries presence in primary teeth; defs score; defs score categories; secondary outcomes: child microbiological presence: mutans streptococci colonisation (any); child microbiological presence; mutans streptococci score categories Additional narrative text for: none Tabulated data for: none Additional outcomes that had not been prespecified: Child: none reported. Mother: none reported
Notes	Funding: "The study was supported by grants from the Swedish Dental Society, the Swedish Patent Revenue Fund and the County Councils of Halland and Västerbotten". Declarations of interest: none declared As fluoride is not an eligible intervention in this review, we have excluded the sodium fluoride/xylitol/sorbitol gum group, and included this trial in the comparison of xylitol versus CHX combined with xylitol.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "Three experimental groups and one reference group were formed on the basis of the maternal MS counts. The mothers with high counts of salivary MS (≥ 150 colony forming units CFU) were randomly assigned to three experimental groups".
Allocation concealment (selection bias)	Unclear risk	Not reported
Blinding of participants and personnel (performance bias) All outcomes	High risk	Not reported; unlikely considering the type of intervention assessed
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "all children were examined in a dental chair by one trained examiner (IT) blind to which group the child belonged".
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	At the 3‐year time point: 56/61 (91%) and 44/55 (80%) of infants were available for assessment in the xylitol and CHX/ and fluoride groups respectively. At the 4‐year data collection time point: 52/61 (85%) and 44/55 (80%) infants of mothers randomised to the xylitol and CHX/xylitol groups, respectively, were available for assessment.
Selective reporting (reporting bias)	Unclear risk	Without access to study protocol, cannot assess confidently as high or low risk
Other bias	Low risk	There were no signs of other bias in the study reporting.