Article History
Received: 7 October 2016
Revised: 16 March 2017
Accepted: 12 April 2017
First Online: 23 June 2017
Competing interests
: SM is an employee of GSK Consumer Healthcare; RK and MH are employed by Oral Health Services Research Centre, which has received funding from GSK Consumer Healthcare; LS is a consultant who received funding from GSK Consumer Healthcare.