Dental anxiety is extremely common and may become a significant deterrent to optimal oral health. It can become a ‘vicious circle’ in which a patient’s anxiety is maintained and increased by a self-perpetuating pattern of dental avoidance, augmented with feelings of shame and inferiority.
Dental anxiety has been described as a reaction to ‘unknown danger or fear of the unknown’. This differs from a dental phobia, defined as an experience based on ‘a fight or flight’ response to ‘a known danger or fear’, making the sufferer feel ‘out of control’. The Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) define it as ‘a marked and persistent fear of a particular object or situation’.
Moderate dental anxiety has been estimated to affect 36% of the population in the UK (Scotland excluding), whilst extreme dental anxiety or phobia affects 12% of the population. The level of anxiety of the interviewed population of 11,380 adults in the Adult Dental Health Survey 2009 was measured using the Modified Dental Anxiety Scale (MDAS). Its findings reported that extreme dental anxiety was experienced by 30% of adults undergoing a tooth cavity preparation; 28% receiving a local anaesthetic injection; 15% while seated in the waiting room; 13% undergoing dental appointment next day and 8% receiving a regular scale and polish.7-8
Numerous publications have reported that dental phobia has an early onset at mean age of 12 years with approximately 50% of dentally fearful individuals indicating that their fear developed in childhood. A further 27% report that their fear originated in adolescence while for 23% it began in adulthood. Among many, the most common determinant factors are pain–related or traumatic dental experiences, dentists’ inappropriate behaviour during or before dental intervention and emotional, behavioural or psychological disorders. The aetiology of dental anxiety and phobia is therefore diverse and often multifaceted.
There is an estimated 11,000 dentally anxious adults in the UK, therefore it is critical that dental care professionals assess a patient’s anxiety levels and utilise appropriate intervention to help to reduce their anxiety. Hypnosis, as a method of reducing dental anxiety, may provide some patients with an effective ‘sedation’ at the same time as reducing or eliminating their dental anxiety and phobia.13 Recently a trial protocol has been published in the Cochrane library to examine the effect of hypnosis in reducing dental anxiety in adult patients.15
This paper will focus on the efficacy of hypnosis in reducing dental anxiety in an adult population.
A literature search was conducted using online databases available through Medline /PubMed, Science Direct, the Knowledge Network, Google Scholar, UHI Multisearch, Wiley Online Library, Sage Publishing and the Dental Update Website, The Society for the Advancement of Anesthesia in Dentistry, and text books and further review of references within papers reviewed were also reviewed.
Papers were excluded if they were not published in English language and if the population sample were not adults aged 18 years and over, undergoing dental treatment under hypnosis. Hypnosis was used as either stand-alone intervention or as an adjunct or comparison to other pharmacological or behavioural intervention and/or a control group.
The search for the review was limited to papers published from 1981 to present, and only peer- reviewed journals were used. Key words used were dental anxiety/fear/phobia in adults, dental hypnosis in dentistry, dental hypnosis for dental anxiety/fear/phobia, efficacy of hypnosis in dental anxiety.
In order to distinguish between the hypnosis used in the reviewed studies, the author has developed a simple nomenclature: ‘live hypnosis’ (LH) is that which is delivered by the clinician, and ‘audio hypnosis’ (AH) hypnosis delivered using a tape cassette recording or CD.
In total only 14 papers met the search criteria and were reviewed.
The dates of publications range from 1981 to 2014. Three studies were published between 1981 and 1996, eleven studies between 2000 and 2014. Eleven studies were carried out in Europe, two in the United States and one in the Middle East. The references of included studies were reviewed whenever necessary. The majority of studies were observational studies from which two were longitudinal studies16-17, one cohort study3 two case-control studies,18-19 and six case-report studies. 9-11,13,20-21 Only three were experimental studies, including one comparative clinical study22 one prospective study23 and one randomised control partially blinded trial.24
All subjects in the reviewed literature were adults ranging from 18 to 80 years old. In total there was 762 participants, from which 311 were males (40%) and 451 were females (59%). Eight studies included a mix of both genders 3,16-19,22-24 whilst six studies included only females.9-11,13, 20-21
In total, 21% of studies included patients presenting with a clear medical history, while nearly 36% of studies included patients who had a complex medical history, or no medical history was provided.
One of the reasons why hypnosis was chosen in 28% of the studies was due to the patient’s complex medical history.9-11,20-21
An example is the earliest report reviewed, which is more than 30 years old.20 This discussed the case of a 29 year-old female who had severe cardio- pulmonary disease, suffered from extreme dental anxiety with an inability to accept local anaesthesia for dental treatment. In this case, the use of hypnosis was the only option to ‘sedate’ the patient and deliver optimal dental treatment, as the use of pharmacological methods, such sedation or general anaesthetics (GA) was contra-indicated due to the patient’s medical history.
Hypnosis by eye distraction and progressive relaxation, together with ego strengthening, was employed. The patient was taught autohypnosis, which kept her calm and relaxed not just for successful completion of this treatment but also for future dental visits. Despite successful treatment of the patient, this study exhibited many limitations, most notably its lack of any reliable methods to measure pre and postoperative anxiety levels using reliable scales such as Corah’s or modified Corah’s dental anxiety scale.7-8
Patients also presented with additional fears or phobias.3 In other cohort case studies, in a addition to dental anxiety the researchers included disorders, such as ‘additional specific phobia’, ‘social phobia’, ‘agoraphobia’, ‘generalised anxiety disorder’ and ‘effective disorder’ among its patients.9-11 Alarmingly in 64% of those studies with participants reporting high levels
of anxiety, 44% were identified as patients suffering from dental needle phobia.3,9-11,13,21 The results of these studies found that the application of hypnosis delivered to the patient helped to reduce both their anxiety levels and their dental needle phobia.
In one case report9 the authors described the effectiveness of short-term delivered hypnosis for reducing dental needle phobia in a 48-years old female with a complex medical history and additional fears of heights, spiders, snakes and flying. The patient was ‘self-administering’ a number of injections for numerous medical conditions, which she described as ‘painful’ and ‘burning’, but did not fear them. Interestingly, the patient only complained of dental anxiety and ‘dental needle phobia’ that she believed was triggered by a traumatic dental extraction when she was only five years old. The application of hypnosis with ego strengthening to aid muscle relaxation allowed the author to carry out successful needle desensitization with the patient. The results of the patient’s level of anxiety scores were measured using MDAS with significant reduction between pre-treatment (MDAS = 26/30) and post-treatment (MDAS=12/30). The patient MDAS post hypnosis indicated low-level anxiety that would be common in patients with no dental anxiety.
The author of a case involving a 55-year-old visually impaired female with dental phobia (DAS = 20/20; MDAS=29/30) also reported additional fears, in this case it was wasps and cats. The patient had previous painful dental experiences and believed that these had also contributed to her phobia.
The application of hypnosis with ego strengthening allowed the author to carry out needle desensitisation with the patient. Applying the principles
of tell/show/do on instruments needed in the next appointment was a
very important part of acclimatisation for this patient. The results of the patient’s level of anxiety scores showed a significant reduction post-treatment (DAS=10/20; MDAS = 14/30).11
Two papers refer to the presence of several additional fears as a possible indication for an innate predisposition and preparedness to anxiety and discuss the ‘Pavlovian conditioning’s’ as a widely accepted and significant cause of dental phobia. The importance of trust between dentist and patient is ‘pivotal’ in relation to reducing a patient’s anxiety and fear when visiting a dental environment.9,11
All papers used a different form of measure to assess the level of their patients’ anxiety. Although almost 86% of studies used the self–reporting method to measure anxiety levels, the heterogeneity of those measures has made the comparison of outcomes between studies problematic and posed as a great limitation to reliability of the evidence.
Table 1. Describes different self-reporting anxiety measuring methods in the reviewed studies.
|Visual analogue Scale||AZI||A German scale that was modified from Corah’s DAS; 6-item questionnaire assessing affective, cognitive and somatic reactions. Overall total can be between 0-60|
|Norman Corah Dental Scale||DAS||4-item questionnaire measure individuals tendency to be anxious about or during dental treatment; each question scores 1-5 with (5) being ‘most anxious’ and with overall ranges from 4-20.|
|Corah’s (Modified) Dental Anxiety Scale||MDAS||Modified version of Corah’s DAS including extra question relating to Local Anesthesia. Total scores ranges from 5-25|
|State-Trait Anxiety Inventory||STAI||Sometimes called Spielberger’s 20 questions that are divided into 2 groups: 20 for assessing Trait anxiety and 20 for State anxiety. Each question is scored1-4, where (4) means ‘most anxious’|
|Dental Fear Survey||DFS||Measures existence of other phobias and fears.
24 questions with answers scoring from 1-5, with (1) ‘ no fear’ and (5) ‘extreme fear’; Final scores ranges from 24-120.
|Gear Fear Scale||GFS||Measures existence of other phobias or fears|
|Dental Anxiety Questionnaire||DAQ||Two part dental anxiety measure; first part multiple choice, second part visual smiley faces represent emotion|
|Dental Belief survey||DBS||Scores evaluated patients beliefs and security in relation to dentist|
|Visual Analogue Scale||VAS||Respondent marks the level of pain they feel on a 10cm continuum long line that records the level of pain from 1- 100.|
|Dental Cognition questionnaire||DCQ||38 questions of negative cognitions (beliefs and statements) related to dental treatment|
|Revised Iowa Dental Control Index||RIDCI||9-item questionnaire, 5 of which relate to desire for control and 4 for perceived control during dental treatment, items rated from 1-5 where (1) no need (5) means need for total control|
|Hierarchical Anxiety Questionnaire||HAQ/ DAH||11 hierarchically ordered phobic situations and graded 1-5|
|Subjective Ratings of Treatment Effectiveness and Treatment Dependence||Carried out at the end of treatment- participants ask to rate the efficacy of the treatment on their level of dental anxiety, rated from 0-3, and what their expectancy of future treatment would be rating 0-4; the highest number would score highest distress or efficacy|
DAS was found to be the most common self-reporting methods used in 35% of studies.3,9-11,16-17,24 STAI was found in 28,5% of studies.3,16-18,24 The State anxiety was used for pre-treatment screening and group comparison by four studies3,16-18 whilst one other used the Trait anxiety as outcome measure.24
Three studies measured dental anxiety with MDAS 9-11 and DFS.16-17,19 The GFS, HAQ, DBS, and DAQ were used in 14% of studies and DCQ, RIDCI and Subjective Ratings of Treatment Effectiveness and Treatment Dependence were used in 7% of studies.
With the exclusion of two studies that used the behavioural method, the remaining studies used a self-reporting method to measure anxiety.13,20
Only two studies have included both self-reporting and physiological or neurophysiological parameters to measure anxiety levels.22-23 Both studies evaluated the effect of audio (tape) hypnosis on patients’ anxiety levels in the placement of implants. A randomly selected group (n=17) of highly (DAS<13) and less anxious (DAS >12) dental patients were compared with a control group (n=8) that underwent the same treatment without the hypnotic intervention. The authors also measured patient’s neurophysiological parameters such as respiratory rate, blood pressure (systolic and diastolic), heart rate, salivary cortisol, pulse oximetry measuring oxygen and temperature. The results showed that hypnosis had a “sedative” effect on the anxious patients and reduced both their dental anxiety to a low anxiety level (DAS=11) as it had equally also decreased their neurophysiological parameters.22
These findings were subsequently confirmed in a prospective study where the patients in the experimental group used a ‘pillow’ playing music with audio hypnosis. The effectiveness of the pillow-audio hypnosis was reflected in a decrease of both the AZI (state anxiety) scores (p=0.000) and the 23 intraoperative diastolic BP and HR in comparison to the control group.
Reliable statistical testing was carried out by only eight studies, which was relevant to the data and verified its reliability.3,16-19,22-24
Characteristics and the results from intervention
Table 2. Summarises the interventions used and outcomes from the treatments in the reviewed studies.
Of all studies reviewed, 71% used hypnosis delivered by a trained clinician and found that live hypnosis was beneficial in reducing dental anxiety in adults.3,9-11,13,16-17,19-21
One research group divided 137 highly anxious patients into 4 groups (LH, AH, CBT and GA) and compared their efficacy on reducing dental anxiety. Although the results showed an improvement of DAS in all 4 groups between the start of the treatment (M1) and the final visit (M4), (p<0.001), when comparing live vs. audio hypnosis the verdict was in favour of live hypnosis rather than audio hypnosis that, according to the authors, did not show any benefit in the treatment of dental phobia.3
In contrast, the results from three other studies found that the use of audio-hypnosis was effective in decreasing pre and post-operative anxiety.22-24 One paper recorded a series of vomiting post hypnosis, which may be of some limitation to the study.24
One study3 appeared to have a number of bias and a lower grade of evidence. In comparison, the remaining three studies 22-24 were presented with mostly low risk of bias and were graded as the highest level of evidence according to Scottish Intercollegiate Guidelines Network.26
The use of a control group, or intervention, varied between studies. Seven studies compared hypnosis with a control group.16-19,22-24
In a case-control study, a mixed cohort of 24 patients were referred for a surgical extraction of third molars under live hypnosis using either a gaze at one point or a Chiasson’s technique. The authors of the study used the same patients as the control group that had teeth extracted on one side of the mouth under hypnosis, and on the other side with LA only. The result of STAI mean scores (46,8 and 47,4) in the two groups were very close to each other and no statistically significant differences were observed between them.18
Hypnosis was used in five studies as an adjunct to other behavioural therapies including systematic and needle desensitization. 3,9-11,21 study also used audio hypnosis as an adjunct to intravenous and inhalation sedation.24
Comparison with behavioral techniques such as with cognitive behavioural therapy (CBT)3 or the group therapy16-17 indicated that the effects on anxiety were almost identical, with the advantage for CBT which proved to have a better long term dental attendance in comparison to a control group in three years.
Hypnosis was used as an adjunct to specialist procedures or surgeries in 71% of studies, such as implant placement, orthodontics, endodontic or extractions9-11,13,18-24 while only 21% of studies used hypnosis adjunctively to everyday dental treatments, such as scale and polish or dental fillings.9,12,20- 21
When different types of hypnotic techniques such as the Ericksonian, fixing gaze or Chiasson’s were compared with control group, the results in those studies indicated a positive effect on reduction of dental anxiety, regardless of the technique used.18-19,22
Although nearly 86% of studies used the self–reporting method to measure anxiety, the heterogeneity of measures used made the comparison of outcomes between studies problematic and posed as a greater limitation to reliability of the evidence. Three of the included studies in this review did not use any form of validated measure of dental anxiety such as the use of Corah dental anxiety scale (DAS) or its modified form MDAS.7-8,13,20-21
The participants in the review were mostly highly anxious/phobic and of a small to a medium size cohort. Some were treated in a specialist environment, others in a private clinic with a wide range of measures of anxiety and intervention techniques used.
The review revealed a high drop out rate averaging 50% in three studies during hypnotic interventions of highly anxious patients, which were considered a major limitation to these studies.3,16-17 One group of researchers speculated whether the immediate dropouts in their study were related to the fee of EUR 50.00 paid by the audio hypnosis group while the other treatments were free of charge.3
The presence of further bias was related mainly to a lack of patients’ randomisation in a number of studies.3,16-17 In one study the patients were allocated by the referral clinics’ receptionist, whilst the general anaesthetics (GA) was self-elected by patients alone.3 In two longitudinal studies only the systematic desensitisation group was randomly assigned.16-17 In one it was not obvious how patients were appointed between the experimental and control group.19
Interestingly there were recorded episodes of vomiting post-hypnosis as an unexplained side effect of the treatment.24 Also the levels of anxiety prior to treatment were not given in three studies.18,23-24
It seems apparent from some studies that hypnosis delivered by a specially trained clinician is more effective than hypnosis delivered by audio recordings. However, some contradictory results to this were found between three experimental studies that showed a high level of evidence and low bias.22-24
Hypnosis was found effective as an adjunct to both general and specialised dental treatments and the results showed hypnosishad a positive effect on pre- and post-operative anxiety. Despite recommendations that ‘hypnotisability tests’ in order to determine its applicability of hypnosis to individual patients,17 only 50% of studies in this review tested their subject’s hypnotisability. It is estimated
that approximately 20% of patients are not hypnotisable and some of that percentage applies to patients with borderline syndromes
and schizophrenia.13,17 One group of researchers suggested that the predictability of the outcome of hypnosis was linked to the therapist- patient relationship rather than to the patient’s susceptibility to hypnosis. 24
An interesting point was raised that further research is needed with regards to utilising hypnotisability when carrying out hypnosis with a visually impaired patient.11
In agreement with others one paper17 proposed that ‘the trust’ in patient and clinician relationship should be promoted as a primary therapeutic goal to successful treatment as only this type of approach can strengthen patients’ positive attitudes towards dentistry itself, and decrease their anxiety as well.9,11,13
In most of the studies the patients were taught autohypnosis, which they could also self-apply for future dental treatments, as it allowed them autonomy to facilitate such treatments without the need for the presence of a skilled clinician. Additionally it underlined the importance of the need for suitably trained dental clinicians who can both apply this form of therapy and also teach their patients to learn to attribute their success to their own efforts, rather that of the clinicians.9,11,17
The results of all fourteen studies indicated that hypnosis hasa positive effect on reducing dental anxiety in adult patients. Significantly over 43% of studies in this review reported that the aetiology of dental anxiety was related to previous traumatic dental experiences. Most of these studies were small cohorts and of low level of evidence, however they do highlight a possible correlation between aetiology and the existence of dental anxiety. This would be an interesting topic for further research, including large cohorts and randomised clinical trials, especially as 50% of the reviewed papers did not specify this in their studies.
This review demonstrated the efficacy of hypnosis in reducing dental anxiety on adults. Unfortunately, the evidence of bias within studies, the number of poor quality clinical studies together with the heterogeneity of evaluation measures, are a major problem in interpreting the outcomes in order to support the evidence in favour of the efficacy of hypnosis in reducing dental adult anxiety.
For this reason it is necessary to conduct further randomised controlled clinical studies with larger cohorts and agreed measuring methods of anxiety to confirm the effectiveness of hypnosis in reducing dental anxiety among adult patients.
Ladislava Da Prato is originally from the Czech Republic but has lived in UK for over 23 years now. She graduated from the University of Highlands and Islands in June 2015 with a BSc in Oral Health Science, with distinction.
Ladislava undertook postgraduate training in hypnotherapy in November 2015 under BSMDH (Scotland), lead by Dr Mike Gow, and is now competent in the delivery of hypnosis, neuro-linguistic programming and relaxation techniques, as an adjunct to dental care.
There are currently no comments
If you are not yet a member you can register here: Member Registration