Top‐down self‐regulation processes as determinants of oral hygiene self‐care behaviour: A systematic scoping review

Abstract Objectives Understanding the psychological mechanisms that moderate oral hygiene self‐care behavior is anticipated to benefit efforts to change such behavior. Top‐down self‐regulatory (TSR) processes represent one group of relatively unexplored, yet potentially influential, moderating factors. This systematic scoping review aims to explore whether there is evidence that TSR processes moderate oral hygiene self‐care engagement within the current literature. Methods CINAHL, The Cochrane Library, Embase, MEDLINE, PsycINFO, Scopus, and Web of Science databases were searched up to April 2020 for articles that compared measures of TSR processes (such as self‐monitoring, inhibitory control, and task switching) to oral hygiene self‐care behavior, or tested interventions that aimed to change or support TSR processes. Results The search returned 6626 articles, with 25 included in the final sample. Weak evidence supported both the role of TSR processes as moderators of interdental cleaning and the value of interventions targeting self‐monitoring of interdental cleaning behavior. Overall, methodological limitations rendered the findings somewhat inconclusive, with an absence of objective assessments of TSR capacity, and little focus on TSR processes as moderators of intervention effects. Conclusions The inconclusive, but reasonably promising, findings point to the value of continuing to apply TSR processes within studies of oral hygiene behavior. Exploring why interdental cleaning appears more reliant on TSR processes than toothbrushing, employing objective neuropsychological assessment, and measuring TSR constructs within interventions targeting TSR processes, are encouraged. As a scoping review, the study hopes to generate interest and serve as a starting point for further investigation.


| INTRODUCTION
Top-down self-regulatory (TSR) processes are executive functions of the brain that govern the effortful selection and redirection of behavior.
While bottom-up processes represent the formation of beliefs, motivations, and associations that increase the salience of a behavioral option (e.g., increasing perceptions of value, adding cue-associations), top-down processes work to retrieve and compare behavioral options before shifting effort towards a single task or goal (Hofmann et al., 2011(Hofmann et al., , 2012. Without TSR processes, behavior would be heavily reliant on automaticity, leading to engagement solely in actions that are immediately fulfilling or triggered by the immediate environment (Diamond, 2013). This is an important consideration when thinking about preventive health behaviors, as the long-term focus of preventive actions may mean they require sufficient TSR capacity to facilitate being favored over competing alternatives (Hall & Fong, 2007).
Being synonymous with executive functions, TSR processes typically relate to the cognitive tasks of self-monitoring, response inhibition, and task switching (Diamond, 2013;Miyake et al., 2000). The role of these processes in health behavior is also highlighted by Temporal Self-Regulation Theory, which suggests that TSR processes represent the necessary biological capacity required to both ignore unwanted behavioral tendencies and translate positive behavioral intentions into actual engagement (Hall & Fong, 2007). In the oral health field, reduced TSR functionality may explain why a person fails to recall oral hygiene plans, or why they experience difficulties ignoring competing tendencies or redirecting behavior despite knowledge that oral hygiene self-care will be beneficial.
Although the role of executive functions in health behavior has been advocated (Allan et al., 2016;Gray-Burrows et al., 2019), few reviews have explored TSR processes in the oral health field. While there is evidence demonstrating the benefits of self-monitoring interventions (Newton & Asimakopoulou, 2015) and links between conditions such as ADHD (a condition related to difficulties with inhibition and impulsivity) and oral health (Chau et al., 2020), there has been little focus on whether specific TSR processes may contribute significantly to an overall explanation of engagement in preventive oral hygiene self-care.
Deeper appreciation of the mechanisms that underpin positive health behaviors is expected to benefit attempts to elicit behavioral change (Aklin et al., 2020;Hagger et al., 2020), with understanding the role of TSR processes as moderators of oral hygiene self-care thus anticipated to help preventive oral health efforts. However, with limited exploration of TSR processes among existing reviews from the oral hygiene field, such a relationship between TSR processes and oral hygiene self-care is not anticipated to be readily apparent. Establishing whether a relationship exists, therefore, potentially requires broad searching to reveal and assess the applications of TSR constructs within the existing literature. The current study attempts this very goal, taking the form of a systematic scoping review to explore whether existing applications of TSR processes show evidence of moderating engagement in oral hygiene self-care behavior. The aim is to explore: (i) the role of TSR processes as potential moderators of action and (ii) the methods used to apply TSR processes to the study of oral hygiene behaviors. Analysing these aspects is expected to assist in directing future research and offering conclusions regarding the value of TSR processes within explanatory models of oral hygiene self-care behavior.

| Eligibility criteria
Studies were selected if TSR constructs were examined as moderators of oral hygiene self-care behavior, or targeted by an oral hygiene intervention. In either case, studies were required to provide a quantitative statistical comparison and have a full-text version available in Norwegian, Swedish, Danish, or English language.
Psychological and self-care measures had to be self-reported or objective measurements pertaining to a single person. This meant that data from caregivers administering oral hygiene care to patients, or parents cleaning the teeth of their children, were excluded. While the review sought to discuss interventions that targeted TSR processes, it did not aim to review specific intervention designs or behavioral change techniques. For example, self-monitoring and working memory updating represent TSR processes that may be implicitly targeted through keeping a diary or calendar of behavior T A B L E 1 Description of the review design in PICO format

PICO item Definition
Population Any population.

Intervention/independent variable
Any intervention that explicitly targets top-down self-regulatory processes or any quantitative measure of top-down self-regulatory capacity.

Comparison
Any quantitative intervention result, or any quantitative comparison.

Outcome
Any quantified measure of oral hygiene self-care behavior, typically toothbrushing or interdental cleaning. (Carey et al., 2019). However, the review did not aim to collect information pertaining to all uses of dairy interventions, only those that mentioned targeting TSR processes-that is, self-monitoring or working memory.

| Search
The following databases were searched on April 2nd, 2020: CINAHL

| Data collection
Data were extracted through collaboration between three reviewers (AAR, TW, J-AKJ). To address the research question regarding the relationship between TSR processes and oral hygiene self-care, data items included the instruments used to assess oral hygiene behavior and TSR constructs, the methods used within intervention processes, and the observed statistical relationships or effects. Where data were unavailable, corresponding authors were contacted.

| RESULTS
The initial search returned 6626 results. After duplicate removal and screening of the remaining 3257 unique articles, 73 advanced to fulltext review and the final sample included 25 studies and 25 unique populations. A flow-chart of the review process is presented in Figure 1 and demographic information presented in Table 2. Details of the studies excluded during full-text review are provided in Appendix B. The samples included participants from 13 different countries, with a median sample size of 151 participants, and with 60% of samples taken from school or university students.
The included studies showed a distinct preference to focus on either plaque removal via toothbrushing or plaque removal via the use of interdental cleaning aids. Extracted data were therefore grouped based on study design (cross-sectional or intervention) and target behavior (toothbrushing or interdental cleaning), and is presented in Tables 3-6. 3.1 | Findings from cross-sectional studies Table 3 presents data from the studies (n = 8) that examined the relationship between TSR processes and toothbrushing frequency.
Overall, little evidence suggested a significant relationship. However, it should be noted that only one study attempted neuropsychological assessment of executive functions instead of self-report methods (Naorungroj et al., 2013), and only one explored variations in toothbrushing beyond daily frequency (Pakpour et al., 2016), with both studies observing stronger relationships. Only four linear relationships were reported, with three of these between flossing and action control (Hamilton et al., 2018;Schuz et al., 2007;Suresh et al., 2012). Among the flossing studies, there was a reduced tendency to use daily-frequency as the timeframe for behavior with studies favoring weekly or monthly recall periods.

| Findings from intervention studies
Looking at the intervention studies, the data from those that tested TSR interventions on toothbrushing frequency is presented in self-monitoring program, with two reporting positive results (Schuz et al., 2007;Suresh et al., 2012). In 10 out of 17 applications the results suggested a relationship between the use of self-monitoring interventions and increased interdental cleaning behavior.
Overall, the results demonstrated that top-down processes were more related to interdental cleaning behavior than toothbrushing behavior and that self-monitoring interventions may have a positive influence on interdental cleaning frequency. Among the methods, there was considerable heterogeneity in the measures used to quantify oral hygiene self-care and TSR processes, as well as heterogeneity in the design of TSR-focussed interventions. Although the scoping review did not plan to offer rigid comparisons, the apparent general heterogeneity points to some interesting considerations for future study that are discussed below.

| DISCUSSION
This systematic scoping review aimed to explore whether TSR processes play a role in the moderation of oral hygiene self-care behaviors. Based on the current findings, interdental cleaning appears to have a stronger relationship with TSR processes, although due to varied methodological limitations and incomparable construct definitions these findings are somewhat inconclusive. As a scoping review, inconclusive results were neither unexpected nor fruitless. Rather, the results point to interesting gaps in the literature and potential pathways for the continued application of TSR processes within future research.

| Between-behavior differences in association with TSR processes
A key finding from the current review was the differences in association strength based on the behavior in focus. TSR processes, in general, appeared to be more associated with interdental cleaning than with toothbrushing. As executive functions are associated with a range of health behaviors (Gray-Burrows et al., 2019; Reimann et al., 2020), this difference was not anticipated. One explanation is that interdental cleaning may be perceived as more challenging to perform than toothbrushing, with reliance on executive resources increasing with task difficulty (Tun & Lachman, 2008). However, alternative F I G U R E 1 Flow chart of the review process explanations might also relate to the automaticity of toothbrushing behavior or the time-perspective of outcomes linked to interdental cleaning. Automaticity increases with behavioral familiarity, allowing for increased unconscious processing and reducing demand on topdown self-regulatory control (Reisberg, 2013). As toothbrushing is usually emphasized more than interdental cleaning from an early age, it may be predisposed to greater implicit familiarity and automaticity, meaning an increased possibility of engagement in the absence of conscious self-regulatory effort. Hall and Fong (Hall & Fong, 2007) refer to this quality as behavioural prepotency, suggesting that implicit tendencies towards a behavior, based on past familiarity, increase the likelihood of action and present a moderating factor that acts independently of explicit intentions and executive function capacity.
Regarding time-perspective, the temporal proximity of reward outcomes is suggested to influence how competing actions are weighed against one another (Hall & Fong, 2007 (Hall & Fong, 2007). Although task difficulty, automaticity, and time-perspective were not explored within the current studies, they may represent key factors that explain the observed differences between unique oral hygiene self-care behaviors and their relationships with TSR processes.

| Interpretation of intervention effects
The results also point to the mixed effects of self-monitoring

| Strengths and challenges
The current study did have considerable strengths as a novel scoping review concerning a relatively unexplored pathway within the field of preventive oral health. Namely, the review aimed to be broad and impartial, to incorporate learning from the behavioral sciences, and to employ a systematic and inclusive search strategy that avoided testing any particular theory or approach. However, it should be noted that defining where top-down and bottom-up processes differentiate is a topic of continued debate (Evans & Stanovich, 2013). Thus, the selection criteria should be interpreted as an attempt to include higher-order functions occurring within close T A B L E 4 Relationships between TSR processes and interdental cleaning frequency in cross-sectional studies   Flossing, daily frequency, interval measure Initial motivational intervention focussed on education, outcomes, costs and benefits, and intention-formation. After 17 days, the selfregulation intervention was delivered and focussed on goal setting, coping strategies, goal review, and self-monitoring of daily behavior for the following 17 days Self-monitoring plus motivation and goal-setting Lhakhang et al. (2015) 205 (111) Written intervention, single exposure, followed up at the conclusion of a 17-day selfmonitoring intervention Flossing, daily frequency, interval measure Self-regulation intervention focussed on goalsetting, coping strategies, goal-review, and self-monitoring of daily behavior for 17 day Abbreviations: ○, no effect; •, effect registered but no control comparison; ••, more effective than control but not better than alternative treatment; •••, more effective than comparative treatment; CBI, cognitive-behavioral intervention.
temporal proximity to the behavior itself, and a reflection of executive functions associated with task control in the wider literature (Miyake et al., 2000).
This inclusivity, though, resulted in rather inconclusive findings; there were few linear relationships between TSR processes and oral hygiene behavior, and an inability to generalize them based on the apparent heterogeneity. An interesting observation was that three of the five linear relationships involved the construct of action control (Hamilton et al., 2018;Schuz et al., 2007;Suresh et al., 2012), a construct that attempts to capture general capacity for effortful topdown self-regulation. Stronger relationships with broader construct definitions, but not with more specific ones, provides some evidence that while a relationship may indeed exist between TSR processes and oral hygiene behavior, there may be inherent difficulties in isolating and exploring the underlying sub-processes themselves.
One reason for such difficulties can be explained by the methods used to quantify TSR processes. Within the current studies, for example, only one attempted neuropsychological assessment (Naorungroj et al., 2013). Neuropsychological assessment involves testing performance on a behavioral task, with measures shown to differentiate considerably from self-report (Saunders et al., 2018) and with neuropsychological assessment favored within theoretical behavior models that include TSR processes (Hall & Fong, 2013). It is plausible that using objective cognitive assessment may tell a different narrative to the one observed in the present study. Similarly, the study found that measures used to quantify oral hygiene self-care could also benefit from refinement. With weaker relationships generally observed when behavior was measured on a times-per-day basis, it is recommended that recall periods be extended to a weekly timeframe. Not only do daily measures also have a tendency to mirror internalized habits (Hagger et al., 2015), rather than actual behavior, but weekly recall periods offer a reasonably valid approximation that is likely to better estimate the real variability in the target action (Stull et al., 2009).

| Future directions
Overall, the current review may be used as a guide for several novel research pathways. First, future research may consider neuropsychological testing as a means of continuing research into TSR process within the oral health field. With objective measures potentially likely to tell a different narrative, applying neuropsychological assessment and a theoretical framework that includes TSR processes, such as Temporal Self-Regulation Theory (Hall & Fong, 2007), represents an ideal starting point.
Second, experimental studies may consider similar tactics. As evidenced in the health field, executive functions may moderate the influence of behavior-change interventions (Allan et al., 2013). Thus, TSR processes may represent important confounders to consider when assessing intervention effectiveness. For example, if self-monitoring/workingmemory capacity influences participant responses to a self-monitoring intervention, then understanding this relationship is vital to understanding the true treatment effect. For this reason, the current review echoes sentiments to focus on mechanisms of action within experimental studies (Hagger et al., 2020), and especially the inclusion of TSR constructs in intervention studies that target TSR-related processes.

| Conclusion
This scoping review aimed to explore the relationship between topdown self-regulatory processes and oral hygiene self-care behavior. It found that interdental cleaning appears to depend on TSR more than toothbrushing and that there appears to be value in the use of selfmonitoring-focused interventions to improve interdental cleaning frequency. The review recommends that the task-difficulty of interdental cleaning be investigated to explain greater reliance on executive resources, and that future studies aim to employ more objective measures of quantifying TSR processes, especially within intervention studies that target these constructs. TSR processes represent a promising research path and their continued application is expected to improve current explanations of oral hygiene habits and contribute to the continual improvement of behavior change strategies within the oral health sector.

CONFLICT OF INTERESTS
The authors declare no conflict of interest.

DATA AVAILABILITY STATEMENT
The sharing of data is not applicable to this study as no new data were created. 1 self-regulation/or agency/or emotional regulation/or self-control/or self-management/or self-monitoring/or "self-monitoring (personality)"/ 41,274 2 (self adj1 (regulat* or monitor or control* or analy* or conscious or correcti* or criti* or disciplin* or evaluat* or judg* or manag* or observ* or reflect* or restr*)).ti,ab,id. 67,077 3 (action control or agency or attention or autoregulation or behavio?ral disinhibition or behavio?ral inhibition or behavio?ral regulat* or cognitive control or cognitive shifting or (delay* adj3 gratification*) or executive control or executive funct* or focus?ed atten* or impulse control or inhibitory control or introspect* or metacogniti* or mindful* or reflective* or response inhibition or set-shifting or social comparison or task switching or volition* or willpower or working memory Total results: 2316 1 TITLE-ABS-KEY (self PRE/0 (regulat* OR monitor or control* OR analy* or conscious OR correcti* OR criti* OR disciplin* OR evaluat* OR judg* OR manag* OR observ* OR reflect* OR restr*)) 142,499 2 TITLE-ABS-KEY ("action control" OR agency OR attention OR autoregulation OR "behavio*ral disinhibition" OR "behavio*ral inhibition" OR "behavio*ral regulat*" OR "cognitive control" OR "cognitive shifting" OR (delay* W/2 gratificat*) OR "executive control" OR "executive funct*" OR "focus*ed atten*" OR "impulse control" OR "inhibitory control" OR introspect* OR metacogniti* OR mindful* OR reflective* OR "response inhibition" OR "set-shifting" OR "social comparison" OR "task switching" OR volition* OR willpower OR "working memory") Total results: 1247 1 TS = (self NEAR/0 (regulat* OR monitor or control* OR analy* or conscious OR correcti* OR criti* OR disciplin* OR evaluat* OR judg* OR manag* OR observ* OR reflect* OR restr*)) 110,925 2 T S=( "action control" OR agency OR attention OR autoregulation OR "behavio$ral disinhibition" OR "behavio$ral inhibition" OR "behavio$ral regulat*" OR "cognitive control" OR "cognitive shifting" OR (delay* NEAR/2 gratification*) OR "executive control" OR "executive funct*" OR "focus$ed atten*" OR "impulse control" OR "inhibitory control" OR introspect* OR metacogniti* OR mindful* OR reflective* OR "response inhibition" OR "set-shifting" OR "social comparison" OR "task switching" OR volition* OR willpower OR "working memory")  Miyake et al. (2000). Dumitrescu et al. (2007) Investigating the relationship between selfreported oral health status, oral healthrelated behaviors, type A behavior pattern, perceived stress and emotional intelligence

ORCID
Did not quantify a top-down self-regulatory construct. Emotional Intelligence did to not relate enough to the executive functions defined by Miyake et al. (2000). (Continues)