Adopting the COM‐B model and TDF framework in oral and dental research: A narrative review

Abstract Background Recent advances in the psychological understanding of health‐related behaviour have focused on producing a comprehensive framework to model such behaviour. The Capability‐Opportunity‐Motivation‐Behaviour (COM‐B) and its associated Theoretical Domains Framework (TDF) allow researchers to classify psychological and behavioural constructs in a consistent and transferable manner across studies. Aim To identify oral and dental health‐related studies that have used the TDF and/or COM‐B as frameworks to guide research and examine the ways in which these concepts have been practically used in such research. Method Narrative review of published literature. To be included, the paper had to (1) state that the TDF or COM‐B had been used and to have targeted at least one construct identified in either framework, (2) include primary empirical data, (3) focus on a behaviour directly related to oral or dental‐related health (eg brushing, applying fluoride varnish, flossing) and/or attitudes, intentions and beliefs related to the behaviour. Studies could include any research design, and participants of any age or gender and include patients, parents or dental health professionals. Findings Nine studies were identified that had drawn on the COM‐B and/or TDF as the framework for their research. Seven of the studies were based on the TDF only, with one employing both the COM‐B and Health Belief Model, and one using the TDF with COM‐B. The nine studies covered a broad range of oral health‐related behaviours including child tooth brushing, fluoride varnish application and non‐ or micro‐invasive management of proximal caries lesions. The populations in the studies included dentists, dental teams and parents of children. All studies adopted only a subset of the constructs within the TDF, often without justification. Conclusions It is encouraging that oral health researchers are adopting standardized psychological frameworks to develop their research and oral health interventions. Future work should build on the small number of studies identified in this review and consider using standardized tools to do so.


| BACKG ROU N D
Including theory in the design of behaviour change strategies is essential, as interventions based on the theoretical modelling of behaviour have been shown to be more effective than non-theorybased interventions. [1][2][3] However, one issue that has faced researchers seeking to develop theory-based interventions for oral health-related behaviour-as well as in the wider health field-was the choice of an appropriate theoretical framework given the large number of frameworks (often with overlapping constructs) available in the psychological literature.
Over the last decade, there has been a concerted effort to synthesize the common elements of different models into a single framework for understanding the psychological determinants of behaviour and to inform the design of interventions. 4  Opportunity has two subcomponents as follows: Physical opportunity (created by environment, for example access to resources) and social (norms and expectations of behaviour). Motivation can either be automatic (such as habits) or reflective (motivational elements such as planning and decision-making). 5 It has been proposed that for behaviour change to take place within oral health settings all three components need to be carefully considered. 6 The Theoretical Domains Framework (TDF) consists of 14 constructs which are mapped onto the COM-B model in order to further analyse the proximal determinants of behaviours. 7 It was produced using a consensus methodology combining 83 behaviour change theories which together contained 128 psychological constructs. 8 Table 1 lists the TDF domains together with a brief definition for each term, while Table 2 identifies the mapping of the TDF domains to the COM-B model.
The aim of the TDF was to help provide an assessment of the broad behavioural barriers and enablers that are thought to underpin behaviour change and, as such, inform the design of appropriately targeted interventions. In relation to the wider health field outside of oral/dental health, citations of the TDF and the COM-B have increased exponentially since their original development. 9 In their recent review of health behaviour interventions, Codwell and Dyson found that the frameworks had been used to design interventions for a wide range of populations including children and young people, parents, overweight pregnant women, pregnant smokers, smokers, sedentary office workers, overweight people, heterosexual men and people with hypertension. Most of these interventions targeted diet and exercise as the behavioural outcome of interest.
The great strength of COM-B and the TDF is the ability to use a common taxonomic framework to synthesize interventions across a range of different settings and research designs, whereas a potential weakness is an opaqueness and lack of clarity pertaining to how constructs within them should be used in practice. 10,11 Nevertheless, oral health researchers have started engaging with both frameworks in order to ground their behavioural intervention work into concrete behavioural science theory. Currently, it is not known to what extent (or how) these frameworks have been used in practice, what questions they have tended to address, with what population groups or which, if any, of their components have been shown to be helpful across oral health interventions. Better understanding of how COM-B and the TDF can be used to shape oral and dental health research is paramount if these frameworks are going to be used routinely in this field.
The aim of the review was to identify oral and dental research studies that have used the TDF and/or COM-B as frameworks to guide the conduct of research, that is, the study's choice of study design, constructs, measures, analytic strategy and to understand how they have done so. It is envisaged that in this way the common elements across studies can be identified and implications of using the COM-B and TDF to enhance oral health-related behaviour studies can be outlined.
Narrative reviews are often seen as 'state of the science' type reviews and are useful for providing a narrative synthesis of previously published information. They are also beneficial for providing a broad perspective particularly on the history or development of a topic. 12 For these reasons we chose to carry out a narrative review the results of which appear next.

| ME THOD
We searched for papers that had used either COM-B or TDF to inform the study design. To be included in the review, the paper had to state clearly that the TDF or COM-B had been used and to have targeted at least one construct identified in the COM-B or TDF.
Judgements were made on the basis of information in the paper regarding the use of one/both frameworks.
We included studies of any design which analysed primary empirical data including randomized controlled trials, controlled clinical trials, cohort studies, case-control studies, qualitative interview/ focus group studies and those using mixed methods.

TA B L E 2 The COM-B Model and its relation to the TDF
Studies could include participants of any age or gender and could include patients, parents and dental health professionals.
We included studies focusing on a behaviour directly related to oral or dental-related health (brushing, applying fluoride varnish, flossing) and/or attitudes, intentions and beliefs related to the behaviour.
As the aim of the review was to identify oral and dental healthrelated studies, we only included health behaviours (eg smoking, alcohol consumption) that have been linked to certain oral health conditions (eg periodontal disease, oral cancer) if they were specifically situated within / targeted to the oral/dental healthcare context (eg providing smoking cessation advice in the dental clinic). Instead of using specific search terms, we located studies for inclusion in the re- ing titles, keywords and abstracts. Any papers that did not meet the inclusion criteria were rejected at this stage. There was a disagreement on one study, and the two reviewers were able to resolve this through discussion. Full papers were retrieved for all studies that appeared to meet the inclusion criteria. Further review led to the rejection of some papers at this stage.
The two reviewers independently extracted data for each study on a data sheet designed for the study. We based the structure of our extraction sheet on consultation with experts on the development of the COM-B and TDF and on the Template for Intervention Description and Replication. 14 The variables extracted from each of study were the author(s), year of study and country in which it was conducted, along with the journal title. Summary information from each paper was recorded as the aim, purpose and/or objective of the study, and the research design. Detail of the methods included the sampling technique, recruitment strategy and process and the participant characteristics (including age range, gender). The frameworks used (TDF and/or COM-B) were recorded, together with any rationale given for its use, and the measures used to operationalise the framework components. The main outcome and how it was measured were recorded, and any rewards that were given to participants for taking part. If the study was qualitative, the type of data analysis, together with how rigour (eg second coding) / saturation was assessed. If the study was a quantitative intervention study, the rationale for the intervention was recorded, together with the materials and procedure for the intervention, including how it was delivered, where and by whom, and whether there was any intervention tailoring (personalisation), modifications during the study, and fidelity. Finally, the findings of the study were extracted, including the main (behavioural) outcome, as well as any secondary outcomes.

| RE SULTS
A total of 2153 articles were screened and 2116 papers excluded because the papers did not report on research carried out in dental/ oral health settings. The remaining 37 full papers were read independently by two authors (HB and KA) and were assessed for eligibility. In the end, 9 papers were included in the review. The process and flow diagram of study selection appear in Figure 2. Table 3 lists the characteristics of the nine papers included in the review. The studies identified show that research was carried out internationally within Europe and North America. The published outlets for the research include both dentistry-specific journals [15][16][17][18][19] (N = 5), Implementation Science journals (N = 3) and one in a Gerontology journal. 20 A wide range of participants has been studied including: dentists, 21,22 dental teams 23 and parents of children. 16 The studies used a variety of different designs, such as qualitative, natural experiments and surveys, although the definition of these designs was of variable description and quality. Most did not include an intervention as such, but several included natural experiments, for example exploring different behaviours before and after guidance was published. 18,19 In terms of the oral health-related behaviours studied, researchers have examined a wide range of these,

| D ISCUSS I ON
The COM-B model has been widely used to identify what needs to change in order for interventions to be effective in changing healthrelated behaviour, 24 with the TDF also being increasingly utilized.
The aim of our review was to identify oral health research that had adopted the COM-B and/or TDF as a guide to the development of the study.
It was encouraging to see that some researchers are adopting these psychological frameworks to design studies to further our understanding of correlates of oral health-related behaviour and that From a practical point of view, while it is encouraging to see that the TDF has been used in a small number of oral and dental studies, the COM-B model is employed rarely. This is a surprising find To identify barriers and enablers to dentists non-or micro-invasively managing proximal caries lesions

TDF (Partial)
Barriers: -patients' lacking adherence to oral hygiene instructions -being high-caries risk -financial pressures and a lack of reimbursement -unsupportive colleagues -not undertaking professional development -sense of anticipated regret Enablers: -professional belief that early noncavitated lesions can be arrested -having up-to-date info, supportive colleague/work environments -working as part of a team -having the necessary resources -undertaking ongoing professional development -membership of professional groups -satisfaction from working in the patient's best interest.

Maramaldi et al (2018) USA
To propose empirically and conceptually supported interventions that might increase the capability and opportunity to provide oral hygiene care and oral cancer screening in long-term nursing care facilities.

Whole COM-B (& Health Belief Model)
Findings suggest testing interventions targeting (a) high barriers/low opportunity/low service provision; (b) low capability/low service provision; and/or (c) high benefits/ high capability/high service provision.

Jeggle et al (2019) Germany
To understand why German dentists are reluctant about selective carious tissue removal (SE), and to develop and test two interventions for changing dentists' behaviour Mixed methods TDF (Partial) + COM-B Opportunity and Motivation +the Behaviour Change Technique Taxonomy Version 1

Qualitative findings:
Barriers: -lack of guidelines -discrepancy between established and 'new' knowledge -lack of routine Facilitators: -understanding the biological foundations for SE -having reliable criteria for determining the endpoint of SE Intervention findings: For both interventions, the outcome behaviour (simulated) improved significantly after the intervention (dentists were 'less invasive' after both interventions). There were no significant differences between the two interventions.

Marshman et al (2016) England
To explore parents' experiences of tooth brushing with their young children and to establish barriers and facilitators to parental supervised brushing (PSB) at individual, interpersonal and environmental levels  To determine whether further intervention is required to translate the SDCEP (Scottish Dental Clinical Effectiveness Programme) guidance recommendations for the prevention and management of dental caries in children into practice.

Findings:
The results highlight a gap between current practice and recommended practice. The majority of dentists do not 'always' perform recommended behaviours, and many are following treatment strategies specifically not recommended in the guidance. More positive attitude, greater capability and motivation were significantly associated with performing more guidance recommended risk assessment and prevention behaviours.

TA B L E 3 (Continued)
studies published in journals. Thus, we may not have included some of the most up-to-date research on the COM-B and TDF. However, the focus of our review was to specifically assess the published work on this model and framework.
In conclusion, this review has identified that some oral health researchers are adopting psychological frameworks such as COM-B and TDF to ground their research. However, this is currently limited both in the small number of studies adopting these frameworks and the comprehensiveness of their adoption. We recommend that researchers interested in the development of approaches to understanding the psychological determinants of oral health-related behaviour, and in the design of interventions to enhance such behaviour, adopt the COM-B and TDF framework and associated elements in such research as well as use standardized methodologies to the design and conduct of interventional research. 5

CO N FLI C T O F I NTE R E S T
The authors have no conflicts of interest to declare.

AUTH O R CO NTR I B UTI O N S
SB commented on the manuscript; JTN carried out initial searches and commented on the manuscript; HB and KA carried out searches, screened papers, drafted and revised the manuscript.