###### Abstract  
Patients with a high level of anxiety anticipate extremely intense pain during dental treatment and frequently avoid visiting dentists, showing a tendency to become caught in a vicious circle of pain-anxiety-avoidance. This research aimed to examine whether dental anxiety mediates the impact of pain anticipation before endodontic treatment in the subjective avoidance of future treatments as a function of positive affect (moderating variable). One hundred consecutive patients that required endodontic therapy were enrolled in this study. In this prospective observational study, patients had to fill out a questionnaire twice: (a) first, prior to treatment (a baseline measurement including pain anticipation, MDAS (dental anxiety), PANAS (positive affect), ASA-PS (physical health), previous medication, an assessment form, and pulpal / periapical status); (b) second, once treatment had ended, the patients were registered for subjective avoidance and their number of canals of treated teeth. The results showed a significant correlation between pain anticipation, dental anxiety, and subjective avoidance; furthermore, the index of the association between pain anticipation and dental anxiety was diminished at higher levels of positive affect. In conclusion, there does not seem to be a direct and deterministic association between pain anticipation, dental anxiety, and subjective avoidance, but rather this relationship would depend on the possible influence of the personality variables of the patients. root canal treatment; pain anticipation; dental anxiety; subjective avoidance; positive affect; previous medication 2023  
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(i.e., vicious circle) because they avoid dental treatment due to overestimated pain [9; 12]. Particularly, endodontic therapy is one of the dental treatments that causes the highest anxiety and pain overestimation in patients [13]. Additionally, previous studies highlighted the fact that the incidence of pain increased as the pulpal histopathosis worsened [14]. Patients who reported dental pain often already had a history of pain in the same tooth [14]. Having suffered repeated pain can make them more anxious when they attend the dentist. In general, patients who need root canal treatment are in this vicious circle due to years of missing regular dental check-ups or avoiding preventive treatment [15; 16; 17]. Thus, the vicious circle of pain-anxiety-avoidance should be faced by governments because it harmfully affects oral health and represents a failure in preventive treatments. In order to gain knowledge of this complex relationship, biopsychosocial approaches constitute effective instruments that can progress deeper into patients' personality traits that could be affecting this vicious circle [18; 19]. In this context, this study aimed to examine whether dental anxiety (mediating variable) mediates the effect of pain anticipation before endodontic treatment (independent variable) on the subjective avoidance of future treatments (assessed at the end of endodontic therapy) (dependent variable) as the function of a positive affect (moderating variable). We hypothesized that positive affect (moderator) operates on dental anxiety, which is statistically reflected by an interaction between dental anxiety and positive affect. Figure 1 illustrates the hypothesized process. In order to achieve this goal, three steps were carried out, examining (1) whether anticipation of pain before endodontic treatment affected subjective avoidance through dental anxiety (i.e., dental anxiety as mediator), (2) whether the effect of the pain anticipation on dental anxiety depended on the level of positive affect and how this effect influenced the mediation (whether the mediation is moderated by positive affect), and (3) whether this moderated mediation was maintained after controlling for the possible influence of different endodontic variables (only those with statistically significant relationships with the variables under study).