Introduction

The gag reflex is an involuntary response that protects the pharynx and throat from foreign objects.1 It was likely developed as an evolutionary preventive measure to prevent choking. Although all humans can exhibit a gag response, the level and type of stimulation necessary to trigger it vary among individuals.2 A sensitive gag reflex can hinder dental treatment, leading patients to avoid dental care due to discomfort and fear.3 Therefore, finding ways to manage this reflex in dental settings is crucial.

Psychological factors play a significant role in the frequent and sensitive gag responses observed during dental care.4,5 Trigger areas are often unique to patients and may be linked to past negative dental experiences.6 Additionally, sensory stimuli, such as the sound, smell, sight, or even the thought of dental treatment can provoke a gag response in some people.7 Associative learning is a key psychological process involved, where patients learn to identify certain stimuli as triggers for gagging, leading to avoidance behaviours.8 Strong beliefs about gagging, such as fears of choking, embarrassment, or gagging itself, further contribute to the avoidance of dental care.9 Psychological therapies aim to help people break these associations and develop coping skills to manage moments of heightened distress.10 This suggests that targeted psychological interventions may effectively reduce the severity of the gag reflex and improve patient comfort during dental treatments.

Various approaches for managing the gag reflex during dental treatment have been proposed. However, there is limited evidence and clinical guidance to support dentists in effectively managing this reflex during treatment.11,12 Furthermore, reviews to date have yet to examine the outcomes of psychological approaches to managing gagging during dental care, despite these being commonly proposed as treatment approaches. Therefore, we conducted this scoping review to assess the effects of psychological interventions on the management of gagging in people accessing dental care and treatment.

Objectives

This review examined the effectiveness of psychological interventions for managing gagging among dental patients. The primary objective was to map and synthesise evidence regarding interventions based on psychological models delivered to individuals with gag reflex sensitivity in dental settings, focusing on intervention types, delivery, and outcomes.

Methods

This scoping review was conducted in accordance with guidance from Mak and Thomas13 and prospectively registered on PROSPERO (CRD42024546940).

Eligibility criteria

The following criteria were used to consider studies for this review.

Types of studies

In this review, we included randomised controlled trials, quasi-experimental studies, case-control studies, and case studies examining a psychological intervention used to manage the gag response in dental settings. We excluded opinion pieces and ‘top tip' articles.

Types of participants

Participants of all ages classified as having gagging of any degree of severity (assessed by any means) that impacted dental care were included. We excluded studies involving the following participants: i) those using any medications that might reduce the gag reflex; ii) those with any neurological condition; and iii) those with oral lesions or who have undergone surgery that might alter gag sensation.

Types of intervention

We included any psychological intervention compared to placebo, no intervention, or another intervention, given alone or in combination. For this review, psychological intervention is defined as any range of therapeutic techniques based on a known psychological model or therapeutic approach aimed at addressing psychological factors contributing to the increased sensitivity of the gag reflex. This includes, but is not limited to, systemic desensitisation, cognitive behavioural therapy (CBT), relaxation techniques, and mindfulness-based interventions. Per the aims of this review, we excluded any pharmacological or non-psychological interventions (e.g., acupuncture or laser therapy). Distraction techniques were excluded from this review, as they are not based on psychological models but on general sensory diversion.

Types of outcome measure

The primary outcome examined was whether dental treatment was completed without any observed gagging. Secondary outcomes included: i) a reduction in gagging measured by any scale or method and assessed by the patient, clinician, or both; ii) patient satisfaction with the intervention measured by any scale or method; and iii) any adverse effects related to the intervention.

Information sources

The following databases were searched using a combination of MeSH (Medical Subject Headings) headings and free-text search terms: Medline, Embase, CINAHL and AMED. Abstracts from scientific meetings and conferences were searched using the International Association of Dental Research and the American Association of Dental Research Conference Proceedings. Furthermore, reference lists of included studies were searched to identify additional studies. The search was not restricted by language or date of publication. The database searches were conducted on 24/06/2024.

Search strategy

The search strategy used for this review is outlined in the Appendix 1. This was adjusted as necessary to meet the specific requirements of each of the aforementioned databases.

Selection of studies

Two review authors (MS and FOD) independently screened the titles and abstracts from the electronic searches to identify potentially eligible studies. We obtained full-text copies of all eligible and potentially eligible studies, and these two review authors further evaluated the studies for inclusion. Covidence systematic review software by Veritas Health Innovation was used for screening studies identified by the search.

Any reasons for excluding a study at full-text review are recorded below. Disagreements were resolved by discussion, and articles in languages other than English were assessed by their abstracts where possible. We obtained and translated the full-text articles if they appeared to be potentially eligible.

Data extraction and management

Two review authors (MS and FOD) independently completed data extraction using a data extraction form designed explicitly for this review. The following details were recorded for each included study:

  • Study characteristics (e.g., author[s] names, year of publication, language, and study design)

  • Demographic details of participant(s)

  • Sample size, method of randomisation/blinding if appropriate, method of assessing the outcome, and any dropouts

  • Type or description of the psychological intervention and details of the outcome reported.

Any disagreements were resolved by discussion with a third reviewer (LJSG). For obtaining clarifications, we contacted the authors via email up to a maximum of two attempts. All the details extracted on the characteristics of the included studies were tabulated for descriptive synthesis.

Assessment of risk of bias of included studies

Two reviewers (MS and FOD) independently assessed the risk of bias in the included studies using the Joanna Briggs Institute (JBI) Critical Appraisal Checklist for Case Reports. This checklist was chosen due to the predominance of case reports in the literature. The JBI checklist evaluates the methodological quality of case reports through eight criteria, with responses categorised as ‘yes', ‘no', ‘unclear', or ‘not applicable'. A higher number of ‘yes' responses indicates stronger methodological quality. Results were tabulated to provide an overview of each included study's methodological strengths and weaknesses.

Data synthesis methods

Following data extraction, we conducted a descriptive synthesis of the included studies. This synthesis involved detailing the psychological interventions used to manage gagging in dental settings, evaluating their outcomes, and noting any adverse effects. The aim was to assess the overall effectiveness of these psychological interventions in managing gagging among dental patients, thereby aiding clinicians and researchers in making informed decisions about treatment options.

Ethical considerations

Ethical approval and consent was not required as this study synthesised data from previously published case reports and did not collect or analyse any new data or identifiable participant information.

Results

Study selection

The electronic search strategies identified 857 records, and we had 854 records after de-duplication. We excluded 831 records after screening the abstracts as irrelevant and requested full-text copies of 23 studies for full review. From the 23 studies, we excluded 14 as they did not evaluate a psychological intervention. We assessed the remaining nine studies for eligibility and excluded one additional study because the participant had a neurological condition affecting the gag reflex. Eight studies met the inclusion criteria of this review. A PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) flow diagram is presented below in Figure 1 (see online Supplementary Information for PRISMA Checklist).

Fig. 1
Fig. 1
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PRISMA flow diagram

Study characteristics

The characteristics of the included studies are summarised in online Supplementary Table 1. There was a collective total of 14 participants across all included studies. The collective sex breakdown was 28.6% female (n = 4) and 71.4% male (n = 10). The mean age across all studies was 41.6 years, with a reported age range of 18–65. The included studies all employed case report designs and were published in English between 1970–2022. The primary research objective of all included studies was to investigate whether the sensitivity of a patient's gag response was reduced following a psychological intervention. All included studies examined a psychological approach based on systematic desensitisation. Across the eight included studies, 35.7% (n = 5 patients) received interventions that additionally incorporated techniques from hypnotherapy, 57.1% (n = 8 patients) received applied relaxation exercises, and one study (n = 1 patient) incorporated a thought modification exercise as part of the intervention.

Table 1 The risk of bias ratings for included studies using the JBI critical appraisal checklist for case reports
Full size table

Risk of bias in included studies

The quality appraisal of the included case reports using the JBI checklist revealed several key insights into their methodological strengths and weaknesses. The ratings for the included studies are provided in Table 1.14,15,16,17,18,19,20,21 Additionally, Cohen's kappa level of agreement between reviewers was 0.87, indicating a substantial level of agreement.22

All studies provided clear descriptions of the patient's demographic characteristics, clinical conditions at assessment, and details of the intervention offered. The majority of studies (n = 7) provided a clear patient history. However, this was rated as ‘unclear' in Kavaz et al.17 due to the limited information provided on the patient's past dental or gagging history.

The clarity of diagnostic tests and assessment methods varied across the included studies. Only the study by Ramazani et al.19 received a positive rating, as it used a standardised assessment scale to measure gagging severity. The remaining studies (n = 7) were given ‘unclear' ratings because, while they provided information on what elicited the gag response and its functional impacts, they did not include formal or standardised assessments of the gag response.

Considering the details of the post-intervention clinical condition, six studies were rated positively, as they provided detailed information on the presence of symptoms and whether dental treatment was achieved post-intervention. Two studies had limited descriptions of post-treatment outcomes and were thus rated as ‘unclear'. No studies provided patient feedback post-intervention or quantitative details of change from pre- to post-intervention, and only two studies examined changes after follow-up.

The reporting of adverse or unanticipated events was often not explicitly stated within the studies, suggesting a need for improved reporting standards. Nonetheless, all included studies provided detailed accounts of patient progress and unanticipated events, resulting in positive ratings.

Effects of psychological interventions for managing gagging in dental settings

In all 14 case reports, a patient's ability to tolerate dental treatment was used as the primary measure of the psychological intervention's effect. Additionally, the observation that no gag response was elicited during dental treatment was reported as a secondary outcome in eight case reports. No quantitative data on outcomes were provided; only qualitative descriptions from the case reports were available.

All studies demonstrated that patients could tolerate dental treatment after a psychological intervention. In four case reports, successful dental treatment referred specifically to tolerating procedures such as impression taking or wearing dentures. No adverse effects were reported across the included case reports. Among the eight studies that reported on gag response during dental treatment, seven (87.5%) described the absence of an exaggerated or problematic gag reflex, with patients demonstrating a tolerable or normal gag response that did not interfere with treatment. It is also important to note that one patient (7.1%) continued to experience gagging when swallowing certain foods, despite being able to wear a lower partial denture without gagging. This suggests that while dental treatment was tolerable, the psychological intervention did not entirely eliminate gag-related responses in other contexts. Only two studies (14.3%) evaluated the effects of psychological interventions at follow-up, showing that these benefits were maintained at six and 12 months.

A total of 11 case reports (78.6%) provided details on the number of sessions, with an average of five sessions per patient used to manage gagging in dental settings. Only three case reports (21.4%) specified the frequency of sessions, with patients most often being seen fortnightly. Additionally, three case reports detailed the duration of treatment, which, despite varying significantly, averaged 19.3 weeks and ranged from 2–52 weeks.

Discussion

The current review evaluated the effectiveness of psychological interventions in managing gagging among dental patients. Our analysis included 14 case reports that examined various psychological approaches, primarily systematic desensitisation, to support patients in accessing dental care.

The findings revealed that psychological interventions generally improved patients' tolerance of dental treatments. All patients in the included case reports were reported to have successfully completed dental procedures following the psychological intervention, with reduced gagging observed during treatment. Specifically, 87.5% of the cases reported an absence of gagging during dental treatments following a period of psychological intervention. In several cases, this included tolerating procedures related to denture construction and fitting, such as impression taking or wearing dentures. One patient continued to experience gagging when eating certain foods, suggesting that psychological interventions may not completely resolve gag responses outside of the dental context. The effectiveness of interventions was measured qualitatively, with no adverse effects reported. The most frequently used approach was systematic desensitisation, often combined with other techniques, such as applied relaxation and hypnotherapy. The average intervention consisted of approximately five sessions, with the total treatment duration averaging 19.3 weeks, ranging from 2–52 weeks. Although follow-up data were limited, two studies suggested that the benefits of these interventions were sustained at six and 12 months.

The evidence base for psychological interventions for managing gagging is smaller compared to other treatment modalities, such as acupuncture, which has a larger body of research supporting its effectiveness.23 The limited data available suggest that psychological approaches may reduce gagging during dental treatment, but further research is needed to establish whether these interventions are superior or at least equivalent to other available treatment methods. Additionally, psychological approaches commonly used for managing anxiety related to choking or swallowing may share common mechanisms with those employed in this review, including addressing maladaptive beliefs, introducing ways to reduce physiological arousal, and employing desensitisation techniques.24 These shared mechanisms may help explain the findings observed in this review, suggesting that these well-established principles used in similar contexts could partly explain the psychological intervention effects on reducing gagging.

This review highlights several significant limitations in the literature regarding the use of psychological interventions to manage gagging in dental settings. Notably, there is a lack of quantitative data and standardised methods to measure changes in the frequency or severity of gagging pre- and post-interventions. The limited availability of psychometrically valid tools to assess gagging severity and frequency constrains efforts to evaluate the effectiveness of interventions.25 To address these gaps, future research should employ standardised outcome measures and compare psychological interventions with other treatment methods used to manage the gag reflex in dental settings. Additionally, incorporating patient feedback on the acceptability of psychological interventions would be highly valuable, as this could help identify which patients may benefit most from psychological approaches compared to other recommended treatments for gagging in dental settings.

Furthermore, given the variability in psychological intervention protocols identified in this review, expert opinions from patients, psychology professionals, and dental providers experienced in managing gagging are required to establish a consensus on the most effective ways to implement these approaches in dental settings. Future research employing the Delphi methodology could establish a consensus on the most effective psychological interventions for managing gagging in dental settings. It could also help identify the most suitable practitioners and determine the optimal timeframe for implementing these interventions.

Conclusion

Overall, while psychological interventions show promise for managing gagging in dental settings, further research with larger sample sizes, standardised methodologies, and thorough follow-up assessments is essential before routinely recommending these interventions in clinical practice.