Sintes 2002.

Methods	Trial design: parallel (2 arms) Location: schools in the central plateau of Costa Rica (including San José, Cartago, Alajuela, and Heredia) Number of centres: 28 schools Recruitment period: not stated
Participants	Inclusion criteria: 7‐ to 12‐year‐olds; minimum of one decayed/filled surface (DFS) Exclusion criteria: not stated Baseline caries: (DFS) Gp A: mean 3.69 (SD 2.2); Gp B: mean 3.7 (SD 2.19) Age at baseline: all children were 7 to 12 years old; stratified by age Gender: not stated but stratified by gender Any other details of important prognostic factors: the water supply had a fluoride concentration of less than 0.1 ppm Number randomised: 3394 (not reported by group) Number evaluated: 2539 (Gp A: 1280; Gp B: 1259)
Interventions	Comparison: xylitol plus fluoride toothpaste versus fluoride toothpaste Gp A (n = 1280 evaluated): twice daily brushing for 1 minute with toothpaste containing 10% xylitol plus 0.836% sodium monofluorophosphate (1100 ppm fluoride); participants were instructed to spit out the slurry after brushing and rinse thoroughly with water; eating/drinking was discouraged for at least 30 minutes following brushing; application of toothpaste to toothbrush was supervised Gp B (n = 1259 evaluated): as above but without xylitol Duration of treatment: 30 months
Outcomes	Caries: DFS increment. Assessed at 12 and 30 months Adverse effects
Notes	Sample size calculation: not stated Adverse effects: none observed Funding source: several authors employed (or formerly employed) by Colgate‐Palmolive Declarations/conflicts of interest: not stated
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "Children accepted for participation were stratified into two balanced groups within the participating schools on the basis of age and sex" Comment: although the word 'random' is not used, and we were unable to obtain a response from the corresponding author, we are confident that participants would have been randomised on the basis that: a) the Sintes 1995 study with three of the same authors was randomised; and b) we have information from another Cochrane review that toothpaste trials by Colgate‐Palmolive are normally randomised. However, there is insufficient information on the method of sequence generation
Allocation concealment (selection bias)	Unclear risk	Allocation concealment not mentioned
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote: "Each subject was provided the assigned study dentifrice in tubes with colour‐coded labels, to ensure that the use of the assigned dentifrice was maintained throughout the study" Comment: the use of colour‐coded labels implies that blinding was carried out. We feel that this was probably done properly in this study
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "double blind" Comment: we assumed that this refers to blinding of participants and outcome assessors
Incomplete outcome data (attrition bias) All outcomes	High risk	25% of randomised participants were not included in the final analysis (not reported by group). If the missing participants had higher mean caries increments in one group than the other, as the attrition rate increased, so would over/understatement of the mean difference
Selective reporting (reporting bias)	Low risk	Appropriate outcome measures were considered and reported in full, as described in the methods section
Other bias	Low risk	Caries evaluations were carried out by a single dentist who was calibrated before and during the study. We consider that the risk of differential diagnostic activity was low