AbstractUniversity of Manchester - Catherine Potter - Doctor of PhilosophyINVESTIGATING HYPNOSIS FOR THE ALLEVIATION OF DENTAL ANXIETY - DOES THE ADDITION OF HYPNOSIS TO INHALATION SEDATION REDUCE DENTAL ANXIETY MORE THAN INHALATION SEDATION ALONE28th November 2013Chapter 1 reviews the literature. It gives a historical overview of hypnosis. It reviews the literature on dental anxiety, including its prevalence and aetiology. It reviews behavioural and cognitive behavioural treatments of dental fear. Inhalation sedation its mechanism of action, effectiveness and draw-backs are discussed. The literature on hypnosis is selectively reviewed, its use in anxiety and dentistry and lastly, the combination of sedation techniques, particularly IHS, is discussed. It is concluded that evidence for the use of hypnosis for the alleviation of dental anxiety needs to be critically addressed.Chapter 2 presents the published protocol of a Cochrane systematic review followed by qualitative results of this review. 11 studies of generally poor quality were included in the review which concludes that there are significant problems with the evidence due to methodological issues, the different outcome measures used and the generally high or unclear risks of bias. There is some evidence that hypnosis may help patients who have a normal range of dental anxiety but who are undergoing a stressful dental procedure. Studies of phobic patients were characterised by high levels of drop-out behaviour and hypnosis could not be shown to be superior to other forms of behavioural treatment.Chapter 3 describes two studies which aimed to develop a Mood Induction Procedure to induce temporary dental anxiety in volunteers. This was used in two later studies. A non-clinical sample was used as a 'proof of concept' study was desirable. Study 1tested excerpts of a film, producing only a medium rise in anxiety (ES r = .49). The second study used a shorter, more concentrated film. This produced a large increase in anxiety (ES r=.86). Heart rate was investigated as a possible physiological measure of anxiety, but was not found useful.Chapter 4 describes two randomised controlled studies aiming to investigate whether hypnosis combined with IHS would reduce the anxiety produced by the film more than a control procedure in which IHS was combined with the reading of a story. These studies suggested there may be some effects attributable to hypnosis, but conclusive benefit was not demonstrated.Chapter 5 presents discussion and the overall conclusions of the thesis. Conclusions include the need for further well designed large scale trials involving hypnosis.