Effect of hypnosis on induction of local anaesthesia, pain perception, control of haemorrhage and anxiety during extraction of third molars: a case-control study.

INTRODUCTION: Systemic conditions are considered limiting factors for surgical procedures under local anaesthesia in the oral cavity. All the pharmacological methods to control pain in patients have some disadvantages, such as side effects and extra costs for rehabilitation. Therefore, in such cases alternative treatment modalities are considered, such as hypnosis in dentistry. The aim of the present study was to evaluate the effect of hypnosis on haemorrhage, pain and anxiety during the extraction of third molars.
MATERIALS AND METHODS: In this case-control study, 24 female and male volunteers were included. The subjects had been referred to the Department of Oral and Maxillofacial Surgery, Kerman University of Medical Sciences, for extraction of third molars. Demographic data for all the subjects were recorded. Patients with chronic medical conditions were excluded. The patients were used as their own controls, with the third molars on one side being removed under hypnosis and on the opposite side under local anaesthetic. Hypnosis was induced by one of the two methods, either fixing the gaze on one point or Chiasson's technique; both these methods are appropriate for patients in the dental chair. The Spielberger State-Trait Anxiety Inventory was used to determine patient anxiety levels before hypnosis and anaesthesia. Pain was scored using VAS (visual analogue scale). After surgery the patient was asked to bite on a sterile gauze pad over the surgical site for 30 min when haemorrhage from the area was evaluated. If there was no haemorrhage the patient was discharged. If haemorrhage persisted, the gauze pad was left in place for another 30 min and the area was re-evaluated. Any active oozing from the area after 30 min was considered haemorrhage. Haemorrhage, anxiety and pain were compared between the two groups. Data was analyzed using the t-test, McNemar's test and Wilcoxon's signed rank test using SPSS 18 statistical software.
RESULTS: Twenty-four patients were evaluated; there were 14 males (58.3%) and 10 females (41.7%). The mean age of the subjects was 24.1 ± 2.7 years (age range = 18-30 years). A total of 48 third molars were extracted. In each patient, one-third molar was extracted under hypnosis and the other under local anaesthesia. All the patients were in the ASA 1 category (normal) with no significant medical history. Of the subjects who underwent hypnosis, only two subjects (8.3%) reported pain after induction of hypnosis. In the local anaesthetic group, 8 subjects (33.3%) reported pain. There was a significant difference between the two groups. The results of the study showed that patients in the hypnosis group had less pain during the first few hours post-operatively. Anxiety scores in the two groups were very close to each other and no statistically significant differences were observed in general and when each person was compared with himself or herself. Pain intensity in the two groups at 5- and 12-h post-operatively exhibited significant differences. In the hypnosis group, 10 patients (41.7%) took analgesic medication; in the local anaesthesia group, 22 patients (91.7%) took the analgesic medication (P = 0.0001). In other words, patients reported less pain when they were under hypnosis.
CONCLUSION: The results of the study showed that hypnosis can effectively reduce anxiety, haemorrhage and pain. More studies are necessary to collect data on the effect of hypnosis on oral and maxillofacial surgeries.