Identical survey instruments were used at both sites. Before administration in the field, the questionnaire was reviewed by experienced local researchers, dental academics and health administrators. The survey instrument was adapted from instruments previously employed in SSA [38] . In Tanzania, the survey instrument was constructed and completed in English. In Sudan, the survey instrument was constructed in English, translated into Arabic (the Sudanese national language) and then back translated into English by independent language experts. The survey instrument covered socio-demographic factors and each component of the TPB developed according to the guidelines proposed by Ajzen and Fishbein [39] .