Aim The aim of the study was to investigate: i) the geographical reach and reaction of the online participants engaging in an oral health campaign 'National Smile Month' UK 2016 (NSM); and ii) whether dental practices during NSM were using Twitter to help address regional oral health inequalities.Methods Twitter posts, that is 'tweets', were collected using the application programming interface (API) software Mozdeh, for one month. Tweets were classified into high, medium or low engagement. Participants' postcode data of the organisation/practice were obtained via an internet search using Google. The geolocation of tweets was then linked by organisations' postcode to the 2015 Index of Multiple Deprivation and the oral health survey of five-year-olds 2014/15, and subsequently mapped using Google Fusion Tables.Results A total of 23,100 tweets were captured with a final total of 2,968 usable tweets from 763 separate accounts. Two hundred and twelve tweets were from dental practices, with 107 classified as low engagement, 99 medium, and 45 high engagement (39 of those tweets were from organisations allied to oral health). Interactive maps were created to give a visual representation of the relationship between those participants producing 'high' impact tweets and the level of dental decay in five-year-olds and deprivation levels.Conclusion The majority of tweets did not promote any specific preventative behaviour. Dental practices in England were not contributing to National Smile Month via Twitter in a way that would improve regional oral health inequalities. In areas of high-need there is evidence of proactive engagement with NSM via Twitter by local authorities and their healthcare partners.