The searches across the four databases yielded 173 papers, with 49 duplicates. Of the remaining 124 results, 57 studies were excluded via abstract screening, as they did not meet inclusion criteria. From 67 full texts, a further 42 were excluded, as they did not meet the inclusion criteria for a variety of reasons. In total, 25 full texts were subsequently included for comprehensive review (see Figure 1).

Study characteristics

Online Supplementary File 2 summarises characteristics from all 25 included studies. These included two editorials; one systematic review, synthesising evidence from eight cross-sectional studies; two qualitative studies; one single-blind, quasi-randomised controlled study; fifteen surveys; and six qualitative studies utilising semi-structured interviews or focus groups. Ten papers focused on issues related to childhood obesity only, with insights from the perspectives of both DPs, including paediatric dentists, and parents.13,14,15,16,17,18,19,20,21,22 No studies included the perspectives of administrative and dental assistant staff or commented on their role in the dental teams' contribution to weight stigma.

Papers were categorised regarding main themes relating to weight stigma among DPs and in the dental setting. Qualitative techniques encouraged nuanced and detailed understanding of the research questions under investigation, for example, the exploration of disability-focused themes in a cohort with clinically severe obesity,23 while quantitative analyses assisted in establishing significance and strength of findings.24 Qualitative methods were used in papers reporting direct experiences of patients living with obesity who had experienced weight stigma from DPs.23,25

Attitudes and beliefs about obesity and people living with obesity

Two studies explicitly investigated attitudes and beliefs regarding obesity and people living with obesity, with findings reflecting weight stigma in DPs.26,27 Study populations included convenience samples of dental students in years 2-4 of their studies and dental hygiene students. The study groups were based in the USA and Pakistan.26,27 Participants were surveyed to determine any negative reactions towards the appearance of patients with obesity, whether empathy was challenging, if there were any feelings of discomfort during examination of a patient with obesity, or perceptions of people with obesity by asking if they thought they were ‘lazier, lacking willpower and motivation'26,27 in comparison to patients without obesity. One study found that >31% of a dental and dental hygiene student cohort agreed that they considered people with overweight as having reduced motivation and willpower, and 21% reported negative reactions towards the appearance of a person with obesity.26 In the study by Awan et al., 64% of dental students associated obesity with personality traits of laziness, lack of motivation and self-control.27 Similar results were evident from a US study, which explored attitudes of 518 dental hygienists towards obesity.28 The primary outcome, weight stigma, was assessed using two survey instruments - the Fat Phobia scale29 and the Anti-fat Attitudes Questionnaire30 -revealing mildly negative attitudes and slight fat phobia among dental hygienists towards people with obesity.28

In contrast, another US study reported overall slightly positive attitudes among dental hygienists towards people with obesity,15 using the Nutrition, Exercise and Weight Management Attitudes scale. This study predicted that participants with a positive attitude towards children with obesity were more likely to provide weight-related counselling.15 Of concern is that 7% of participants in this study agreed with the statement ‘I do feel a bit disgusted when treating a patient with obesity'.15

Weight-based discussions with people with obesity related to weight stigma

Findings across multiple studies reported a lack of confidence of DPs to provide education for obesity prevention and management.15,31 Surveys were predominantly used to assess discomfort in asking about dietary habits, initiating discussion of weight issues and asking about current or historical use of appetite suppressants or anti-obesity medications. Providing a contrasting patient perspective from adults with clinically severe obesity, one study reported weight stigma as a factor influencing weight discussions and willingness to engage with the dental team.23 Another study reported that individual engagement with health promotion messages was not influenced by weight stigma towards DPs.32

Qualitative methods were also used to establish perceptions about the role in weight-based discussions and barriers faced by DPs. Both positive and negative perceptions were reported. The most common finding, which was reported in two papers as being statistically significant,14,18 was an apprehension among DPs in providing treatment and concern that they may offend parents or patients, or appear judgemental.14,15,18,21 These were also the major barriers identified in a large US survey involving 2,965 dentists.33 Other barriers to weight-based discussions included the fear of creating dissatisfaction among parents; a perceived lack of accepting guidance about obesity; lack of time; training or knowledge of obesity-related guidelines about best practice; and a lack of appropriate reimbursement.14,15,18,22,33 Several studies found that DPs cited a weak link between obesity and oral disease as a reason for not addressing obesity with their patients.14,18,22,31,33,34

A lack of training was identified in multiple studies as a barrier to obesity prevention and management and weight-based discussions by DPs.13,14,15,18,21,22,31,33,34,35,36,37 In one study, 93% of dental hygienists reported no postgraduate continuing education courses relating to obesity.28 In two other studies, based in the US and Pakistan, there were variable reports of 40% and 78.9% of the dental student and >35% of dental hygienist student cohorts having received up to one hour of obesity education, while 80% reported fewer than five hours.26,27 While number of hours were not investigated, another study involving paediatric residents reported that only 47% received formal obesity education within their specialist training curriculum.20 One included study investigating the inclusion of obesity topics in predoctoral dental curricula in 62 US dental schools revealed that obesity had been incorporated into the curricula; however, this was variably applied practically.38

Service implications - an example of structural stigma

Structural stigma is a type of weight stigma.39 It can occur when institutions, including in the health sector, have policies, procedures, a culture and/or physical environments that disadvantage people with obesity, including via exclusion.9,39 This was reflected in two studies that explored the perspectives of adults living with obesity using focus groups and semi-structured interviews.23,25 Participants described a lack of tailored and suitable services or accommodation of their needs, in addition to discrimination and a lack of awareness of care pathways.25

Similarly, deficiencies within the physical environment were also described in two opinion papers. Descriptions were made of inadequate doorway entry to the practice, mobility issues, inadequate toilet facilities, narrow waiting room chairs without arm rests and the features of the dental chair itself,40 including dental chair dimensions and/or limited safe working weight limits.41 While situations like these can lead to compromised care approaches, this may additionally have medicolegal implications.41

Implications of weight stigma or mitigation strategies in the dental setting

When weight stigma was specifically mentioned, negative impacts on quality and access to dental services have been reported,23,25 and weight stigma should be reduced in order to ensure that comprehensive dental care is provided.28 No specific intervention for reduction of weight stigma in the dental setting was identified from the included studies targeting DPs. It has been documented that unconscious biases held by DPs, and at the institutional level, need to be addressed when providing obesity-related education and managing the dental needs of this population.28