Factors influencing oral hygiene behaviour and gingival outcomes 3 and 12 months after initial periodontal treatment: an exploratory test of an extended Theory of Reasoned Action Jo ¨nsson B, Baker SR, Lindberg P, Oscarson N, O ¨ hrn K. Factors influencing oral hygiene behaviour and gingival outcomes 3 and 12 months after initial periodontal treatment: an exploratory test of an extended Theory of Reasoned Action. J Clin Periodontol 2012; 39: 138–144. doi: 10.1111/j.1600-051X.2011.01822.x. Abstract Aim: The aim was to empirically test the extended Theory of Reasoned Action (TRA) and the prospective direct and indirect role of attitudes, beliefs, subjective norms, self-efficacy, and a cognitive behavioural intervention in adult’s oral hygiene behaviour and gingival outcomes at 3- and 12-month follow-up. Materials and Methods: Data were derived from an RCT evaluating the effective- ness of oral hygiene educational programs integrated in non-surgical periodontal treatment (n = 113). Before baseline examination, participants completed a self- report questionnaire. Structural equation modelling using maximum likelihood estimation with bootstrapping was used to test the direct and indirect (mediated) pathways within the extended TRA model. Results: The extended TRA model explained a large amount of variance in gingival outcome scores at 12 months (56%). A higher level of self-efficacy at baseline was associated with higher frequencies of oral hygiene behaviour at 3 months. Being female was linked to more normative beliefs that, in turn, related to greater behavio- ural beliefs and self-efficacy. Gender was also related to behavioural beliefs, attitudes and subjective norms. Both frequency of oral hygiene behaviour at 3 months and the cognitive behavioural intervention predicted gingival outcome at 12 months. Conclusions: The model demonstrated that self-efficacy, gender and a cognitive behavioural intervention were important predictors of oral hygiene behavioural change. Birgitta Jo ¨ nsson 1,2 , Sarah R. Baker 3 , Per Lindberg 4 , Nils Oscarson 5 and Kerstin O ¨ hrn 1 1 School of Health and Social Sciences, Dalarna University, Falun, Sweden; 2 Dental Health Care Administration in Uppsala County Council, Uppsala, Sweden; 3 School of Clinical Dentistry, University of Sheffield, Sheffield, United Kingdom; 4 Department of Psychology, Uppsala University, Uppsala, Sweden; 5 National Board of Health and Welfare, Stockholm, Sweden Key words: attitudes; individually tailored treatment; oral hygiene; periodontitis; self-ecacy Accepted for publication 16 October 2011 A patient’s engagement in their own oral hygiene self-care is fundamental for a successful outcome in peri- odontal treatment. However, most dental hygienists and dentists have experience of patients who find Conflict of interest and source of funding statement The authors declare that there are no conflicts of interest in this study. The study was supported by Swedish Research Council, Uppsala County Council, Swedish Patent Revenue Fund for Research in Preventive Odontology, and the support of the authors’ institutions. © 2011 John Wiley & Sons A/S 138 J Clin Periodontol 2012; 39: 138–144 doi: 10.1111/j.1600-051X.2011.01822.x