ISRCTN63382258.

Methods	Allocation: randomised Blinding: not clearly described and tested Duration: 12 months Design: cluster randomised controlled trial Setting: Early Intervention in Psychosis (EIP) teams in Nottinghamshire, Derbyshire, and Lincolnshire, UK
Participants	Diagnosis: History: EIP teams, all care coordinators and all service users in the teams N = 26 teams, 1682 participants Age: 18 to 56 years Sex: both Inclusion criteria: Initially any EIP team in Nottinghamshire, Derbyshire, and Lincolnshire and any service users under the care of a care coordinator in one of these teams, aged 18 years or above were included. Later the inclusion was broadened to any EIP team willing to participate for which some sort of follow‐up could be provided Exclusion criteria: Any EIP team that does not wish to take part, any individual care coordinator or service user within a team that does not wish to take part, any service user aged less than 18 years old at randomisation and unable to provide informed consent were excluded
Interventions	1. Staff dental awareness training and dental checklist for service users. N = 882 2. Standard care. N = 800*
Outcomes	Primary outcome: Number of service users who have visited a dentist within 12 months of exposure to the checklist Secondary outcomes: Registered with dentist, routine check‐up within last 12 months, owning a toothbrush, cleaning teeth twice a day, non‐routine visit to a dentist in last year, replacing existing toothbrush within the last 6 months, problems with mouth and teeth, Oral Impacts on Daily Performance (OIDP). A cost analysis was also carried out, and other outcomes included whether any service users have left the EIP service for any reason, including whether they refused to give consent, were discharged to another service, or whether they had passed away
Notes	*Trialists assumed these numbers. Analysis suggested that clustering was unimportant, so data are presented as if individually randomised
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "we then block randomised these; the block being the number of teams within each County" Response: low risk of selection bias
Allocation concealment (selection bias)	Unclear risk	Quote: "The Nottingham Clinical Trials Unit (CTU) created a randomisation program that was used by the researcher to randomise the EIP teams" Response: We do not know which programme was used to randomise the EIP teams
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Blinding of participants has not been described, but it seems that participants and examiners were aware of the interventions
Blinding of outcome assessment (detection bias) All outcomes	High risk	There is no mention of blinding of the outcome assessment
Incomplete outcome data (attrition bias) All outcomes	Low risk	Quote: "Overall the percentage with returns of the second sheet after one year was 31%" Response: Follow‐up data has been clearly reported
Selective reporting (reporting bias)	Low risk	All stated outcomes were reported
Other bias	Low risk	Seems to be free of other biases