Anaesthesia or sedation for dental surgery is Challenging. Over-sedation, leading to upper
airway obstruction, desaturation and apnoea, is very common. On the other hand, it is also
very common that inadequate sedative drugs were given, leading to under-sedation with
unsatisfactory experience during operation. Therefore, it is good if some other methods are
provided for sedation, avoiding side effects associated with sedative drugs.