Description of the condition
Anxiety towards dental treatment is widespread in the population. The latest adult dental health survey in the UK reported that 36% of participating adults had moderate dental anxiety and 12% extreme dental anxiety (NHS information Centre 2010). It is also a global problem, although published figures vary throughout the world. It is also possible that much severe anxiety goes unreported as sufferers may not attend the dentist due to their fear. Dental anxiety and fear of dentistry can be considered facets of the same problem and the terms can be used interchangeably in both lay and scientific discourse.
Dental anxiety is unpleasant for sufferers. There are physical, psychological and behavioural consequences of anxiety and it may lead to neglect of the dentition. Physical effects include shaking, sweating and increased heart rate, sometimes at the thought of dental treatment. Psychological effects include feelings of low self esteem, shame, fear etc. Behavioural changes include the avoidance of dental appointments and in severe cases sufferers may avoid mention of dentists in television, film, newspapers and conversation.
For dental care professionals anxious patients are an important cause of stress as it is often difficult to provide treatment for such individuals. In addition, anxiety may lead patients to cancel their appointments or simply fail to attend their appointments on the day.
Both pharmacological and psychological approaches to overcoming fear of dental treatment are widely reported in the literature, but no one approach is acceptable or applicable to all (de Jongh 2005). Behavioural methods have been shown to be effective and there is some evidence that long term improvement is more likely in patients who receive such methods compared to those who receive pharmacological interventions (Aartman 2000).
Description of the intervention
Hypnosis has been proposed as a potential mode of treatment in the alleviation of dental anxiety and has been used by dentists since the first reports of tooth extraction under hypnosis in the 1800s. Hypnosis in dentistry has been used in many ways. These include as a method of pain control, to control or reduce anxiety towards treatment, to treat dental and needle phobia and to assist in changing habits detrimental to oral health such as smoking (Simons 2007).
According to the British Psychological Society:
"The term 'hypnosis' denotes an interaction between one person, the 'hypnotist', and another person or people, the 'subjects'. In this interaction the hypnotist attempts to influence the subjects' perceptions, feeling, thinking and behaviour by asking them to concentrate on ideas and images that may evoke the intended effects. The verbal communications that the hypnotist uses to achieve these effects are termed 'suggestions'. Suggestions differ from everyday kinds of instructions in that they imply that a 'successful' response is experienced by the subject as having a quality of involuntariness or effortlessness. Subjects may learn to go through the hypnotic procedures on their own, and this is termed 'self hypnosis'" (page 3) (British Psychological Society 2001).
How the intervention might work
Hypnosis has been used to treat anxiety in many contexts not just dentistry. It has been evaluated as an adjunct to cognitive behavioural therapy and considerable benefit was demonstrated in a number of conditions with obesity studies having the largest effect sizes in one meta-analysis (Kirsch 1995) and long term follow-up (Schoenberger 2000). Benefit has also been demonstrated in anxiety disorders, although further well designed studies are needed (Schoenberger 2000).
There may be a number of mechanisms by which hypnosis could relieve anxiety about dentistry. These may be specific to hypnosis or non-specific effects of the therapeutic situation using hypnosis.
During dental treatment, hypnotic suggestions for relaxation may ameliorate anxiety by reducing autonomic arousal. Hypnotic relaxation is used here in a similar way to reciprocal inhibition (Wolpe 1958).
Hypnosis is dependent upon good rapport between hypnotist and subject and the dentist/patient relationship is an important modifying factor in anxiety, a poor relationship increasing the likelihood of a patient becoming anxious. In a survey of Danish adults, anxious people were more likely to have negative experiences of dentists' behaviours (Moore 1993).
Hypnotic procedures could make dental treatment more acceptable which may challenge patient's negative beliefs about dentistry. This could include using techniques aiming to help patients to reformulate memories of traumatic experiences of dental treatment with the help of appropriate intervention by the therapist (British Psychological Society 2001).
Fear of pain is one of the reasons that patients may be anxious and hypnosis is a well established method of pain control (Montgomery 2000).
Hypnosis can potentiate the use of imagery and can be used as an adjunct to techniques such as systematic desensitisation, modelling and other behaviour modification techniques (Simons 2007).
People having hypnotic experiences such as pain sensation show patterns of brain activity closely corresponding to those found when the person has the same experience in reality. It is possible that suggestions to experience other effects, for example relaxation and comfort may reduce anxiety in similar ways (Derbyshire 2004).
Why it is important to do this review
There is published work on the effectiveness of hypnosis as a treatment for dental anxiety, including clinical trials comparing hypnosis to other behavioural methods and to normal treatment protocols (for example Eitner 2006; Hammarstrand 1995; Moore 2002) but so far, the evidence for its effectiveness has not been subject to systematic review. As the public become more interested in complementary approaches in health care in general it becomes more important than ever that evidence is evaluated.
Hypnosis is regarded as a benign procedure. It is recommended that it is used within the expertise of the hypnotist - hypnosis should only be used to treat conditions that the professional would treat without hypnosis. In addition, the British Psychological Society recommends that only those with considerable experience in treating such patients should use it with psychotic patients (British Psychological Society 2001).
Many researchers contend that hypnosis cannot evoke psychotic states such as schizophrenia and that a minority of people report such things as headaches, dizziness, nausea or stiff necks, with a much larger percentage reporting positive effects (Lynn 2000).
However, there are documented instances of adverse effects of the use of hypnosis in clinical and experimental contexts. Most are mild and of short duration, but practitioners should have appropriate training in order to recognise and deal effectively with such occurrences (Gruzelier 2000).
Costs to the patient will vary according to the healthcare system in place, but one US study showed that using hypnosis as an adjunct to sedation may reduce costs (Lang 2002).
Hypnosis is of international interest, the International Society of Hypnosis (ISH) has constituent societies in 19 countries worldwide (ISH 2013).
A similar review of hypnosis in dentistry for children has recently been published (Al-Harasi 2010), so a corresponding review for adults would be desirable.