Many patients regard dental treatment as potentially painful and stressful. Reactions range from ‘normal’ apprehension, through various degrees of anxiety to irrational fear or even phobia.

Conscious sedation is considered by both the General Dental Council and the Department of Health to be an integral element of the control of pain and anxiety. In other words, conscious sedation is an important fundamental aspect of the modern practice of dentistry and should be available to patients.

Conscious sedation depresses the central nervous system and reduces anxiety to allow dental treatment to be carried out. You must be able to talk to the patient and the drug or drugs used must not cause the patient to become unconscious.

This is an overview of current ‘standard’ conscious sedation techniques, before administering any form of conscious sedation the dental team must have received appropriate training.

Patient assessment

A satisfactory first visit is crucial to the success of subsequent treatment under sedation. If possible this is better done in a non-clinical environment. Questionnaires can be used to assess the degree of anxiety. A detailed medical, dental and social history is important and the dental treatment plan must be appropriate and realistic.

Sedation options

  • Nitrous oxide/oxygen mixture with local anaesthesia

  • Intravenous sedation with local anaesthesia

  • Oral or intranasal sedation followed by intravenous sedation and local anaesthesia.

Inhalational sedation

Nitrous oxide in low concentrations with oxygen provides sedation suitable for mildly anxious children and adults and is administered via a nasal hood. Nitrous oxide has excellent anxiolytic, sedative and analgesic properties, with little effect on breathing. Induction and recovery are rapid and administration by titration reduces the risk of over-sedation. The technique does require semi-hypnotic suggestion from the dental team to enhance the sedative effect. The sedationist and the dental nurse must observe the patient's respiration, the level of sedation and skin colour. Pulse oximetry is not routinely used unless the patient has serious medical problems.

The advantages of inhalational sedation include:

  • No ‘needles’

  • Level of sedation easily altered

  • Minimal impairment of reflexes

  • Rapid onset and recovery

  • Some analgesia though local anaesthesia is required for most procedures

  • Can be used for both long and short treatment.

The disadvantages are:

  • Sedation also depends on good psychological support

  • Mask may limit access

  • Nitrous oxide pollution; good scavenging is required.

Contra-indications:

  • Nasal obstruction

  • Poor co-operation

  • First trimester of pregnancy

  • Fear of masks.

Effects:

  • Light-headed

  • Changes in visual/auditory sensation

  • Tingling of hands and feet

  • Suffusing warmth.

Intravenous sedation

Midazolam has an excellent safety record for sedation in dentistry. The correct dose is not based on the patient's age or weight but is determined by careful titration: giving 2 milligrams of the drug, gauging its effect then giving more if required.

Clinical effects

Intravenous midazolam produces a period of detachment for 20-30 minutes followed by a state of relaxation for a further hour or so. Most patients have little or no recollection of the dental care. Some degree of respiratory depression is seen in all patients having sedation with midazolam therefore pulse oximetry must be used.

Advantages of IV sedation with midazolam:

  • Rapid onset (five minutes or less)

  • Good patient co-operation

  • Good amnesia.

Disadvantages:

  • No clinically useful analgesia

  • Respiratory depression

  • Occasional disinhibition effects

  • Occurrence of sexual fantasies (rare)

  • Post-operative supervision for a minimum of eight hours is required

  • Elderly patients are easily over-sedated

  • Less predictable in young people.

Contraindications:

  • Allergy to any benzodiazepine represents an absolute contraindication.

Caution is required with the following groups:

  • Severe psychiatric disease

  • Alcohol or drug abuse

  • Impairment of hepatic function

  • Needle phobia

  • Doubts about the ability to provide a suitable escort.

Oral and intranasal sedation

Oral sedation is useful for patients who are unable to accept cannulations due to needle phobia or a learning disability. The sedation produced may be adequate for the dental procedure to be carried out or it may achieve sufficient relaxation to allow cannulation for intravenous sedation. The most commonly used drug is midazolam which can also be administered intranasally. These routes produce less predictable sedation, as the drug is not titrated to individual requirements. Oral and intranasal sedation must only be administered by practitioners who are also trained and experienced in the use of intravenous sedation.

Summary

Conscious sedation is fundamental to providing dental care and all anxious patients should have access to dentistry in this way. Sedation also helps non-anxious people cope with unpleasant treatment such as oral surgery.

Further reading

Craig D, Skelly D. Practical conscious sedation. London: Quintessence Publishing Co Ltd, 2004.