“…In the volition phase, coping self-efficacy, planning, and action control (such as self-monitoring) are proposed as key self-regulatory factors that are important in ensuring an intended behaviour is initiated, and then maintained once initiated (See Figure 1, Schwarzer, 2008). Several studies have showed the usefulness of the HAPA in explaining oral health behaviour in general (Gholami, Knoll, & Schwarzer, 2015;Hamilton, Bonham, Bishara, Kroon, & Schwarzer, 2017;Hamilton, Cornish, Kirkpatrick, Kroon, & Schwarzer, 2018;Hamilton, Orbell, Bonham, Kroon, & Schwarzer, 2018;Lhakhang et al, 2016;Zhou, Sun, Knoll, Hamilton, & Schwarzer, 2015), and specifically in adolescents (Pakpour et al, 2016;Scheerman et al, 2016;. There is also growing support for the effectiveness of HAPA-based interventions in the context of promoting oral hygiene behaviours (e.g.…”