## 4 Discussion  
This prospective study investigated whether dental anxiety mediated the effect of pain anticipation (before endodontic treatment) on the subjective avoidance of future dental treatments as a function of positive affect. Our results show a significant relationship between pain anticipation, dental anxiety, and subjective avoidance. These results are in accordance with the vicious circle model [34]. Due to the close associations between pain anticipation and dental anxiety found in previous studies, different authors, in the context of dental health, have used fear of dental pain constructs, which emerge as a concept that attempts to explain complex interactions between anxiety and pain [9]. A differential aspect of the current study is that subjective avoidance was measured separately from other variables associated with dental health, such as dental fear. In the study by [PERSON] et al. [11], patient avoidance was registered, requesting if patients had delayed any dental appointments because of fear. In our opinion, it is important to study differential behavioral variables to understand the influence they have on the separate time points of dental treatment. Regarding the medical variables registered in the present study, another result was that only prior medication held a significant association with the variables that made up the pain-anxiety-avoidance vicious circle. This result is in accordance with previous research that has shown that people with a high level of anxiety look for dental care solely when they are in pain [35]. One of the most novel aspects of the present study is that it introduces the possible influence of personality variables in patients within the pain-anxiety-avoidance vicious circle. The results of the present study demonstrated that the value of the association between anticipation of pain and dental anxiety was diminished at higher levels of positive affect. In this way, the indirect effect of pain anticipation on subjective avoidance via dental anxiety was higher in patients with a lower positive affect. Therefore, there does not seem to be a direct and deterministic association between pain anticipation, dental anxiety, and subjective avoidance, which contradicts what previous studies have shown [9; 17]. Over the past few years, certain psychological flexibility models within the Acceptance and Commitment Theory (ACT) have supported this type of result [36; 37]. What this model proposes is that as opposed to a linear and clearly determined relationship between variables, what actually occurs is that associations are much more complex and depend on interactions with moderating and mediating variables, such as situational, contextual, and personality factors [38; 39]. In dentistry, the Acceptance and Commitment Theory has scarcely been studied. As far as we know, only [PERSON] et al. [40] used ACT as a theoretical framework to promote behavioral changes in young adult patients with dental caries. Their study focused on the prevention of dental caries, acting upon bad habits such as sugar consumption as well as upon hygiene techniques and regular dental visits. This type of preventive strategy allows for more conservative and minimally invasive dental treatment of patients. Their suggestion, by means of the ACT, allows for individual risk prevention of oral diseases due to certain risk factors [39; 41; 42; 43]. In the current study, a precise personality factor (positive affect) has been shown to establish differences between the relationship between anticipation of pain and dental anxiety and the whole pain-anxiety-avoidance vicious circle. These results could be discussed within the area of personalized treatments. Therefore, in this case, the association between pain anticipation and dental anxiety is personalized based on each patient and is closely associated with personal traits, specifically positive affect.