 All patients undergoing wisdom tooth removal on both sides, of similar surgical difficulty, to be carried out under a General Anaesthetic of the Daycase Unit of One Hospital will be eligible. Both extractions will be carried out by the same surgeon. Participants who undergo complications during or after the procedure will be excluded from our study. Extractions which end up being too dissimilar will also be excluded, and patients unsuitable for use of the Hilotherm mask for example allergies will also not be considered. Any patients with immune system affecting diseases, and patients who suffer allergic reactions to pharmaceutical agents will also not be considered. 