Sedation is the reduction of agitation experienced by patients through the use of medication and is commonly used in dentistry. The type of sedation used can range from a tablet taken before the appointment to a hospital stay for a general anesthetic.
There are many reasons for using sedation in dentistry. In general, it allows for more difficult procedures to be carried out, for more treatment to be carried out in fewer appointments, and for simple treatments to be carried out in patients otherwise too anxious.
Treatments typically requiring dental sedation include;
- minor oral surgery, such as the removal of wisdom teeth,
- reconstructive surgery
- some cosmetic surgery, especially those involving dental implants.
Types of sedation
There are different ways patients can be given drugs in order to receive dental treatment. Three are types of conscious sedation, and the fourth is general anesthetic:
- Oral sedation
- Inhalation sedation / relative analgesia
- IV (intravenous) sedation (injected into a vein)
- General anesthetic
We will look at these in more detail now.
This is the taking of medication in tablet form before treatment begins.
Often diazepam (trade name Valium) or midazolam (trade names include Versed, etc) are used for oral sedation.
Midazolam is shorter acting than diazepam and so is more useful for shorter treatments, for example with simple treatments on very nervous patients. Its amnesic properties are better and many patients report their experience of the procedure is similar to having a general anesthetic, whereby they remember little afterwards.
There are situations where caution is required with these drugs however, including:
- where patients take drugs which interact with drugs like diazepam and midazolam
- in elderly patients
- in children
- during pregnancy
- in patients with kidney or liver impairment
- in cases of alcohol or drug dependency or abuse
- in patients with certain types of psychiatric disorder
- patients who take other drugs which depress the nervous system.
There is also a long list of other drugs which can be used as oral sedatives including triazolam (Halcion), zaleplon (Sonata), lorazepam (Ativan), among others. A doctor or dentist may choose these depending on whether the patients have any of the issues listed above.
Inhalation Sedation / Relative Analgesia
Inhalation sedation is where a patient breathes in the sedative in the form of a gas. The desired effect is that the patient is less sensitive to pain but still fully conscious. It is almost exclusively carried out with nitrous oxide (laughing gas) mixed with oxygen, and is relatively common to be used in an ordinary dental surgery. In sedation dentistry, the gas is inhaled through a nose mask, inducing a state commonly referred to as ‘twilight sleep’.
Nitrous oxide has an extremely long history and has been proved very safe over many years. It is difficult to overdose on nitrous oxide, side effects are relatively minor generally and it is relatively hard to achieve full anesthesia when used properly.
The few reasons not to use nitrous oxide in dentistry would be;
- the inability to use a nasal mask (in patients with sinus problems or very difficult children susceptible to crying).
- middle ear / sinus disease
- patients who have been scuba diving in the previous 24 hours
- violently disturbed psychiatric patients.
IV sedation is where sedatives are injected intravenously (directly into a vein) just before treatment. The drugs used are often midazolam and diazepam, similar to oral sedatives, but there is a long list of alternatives depending on the requirements of treatment of medical issues in the patient.
In the US, drug administration is taught at a high level and therefore a large variety of combinations of drugs are used, although midazolam is the most common.
- diazepam (Valium)
- meperidine (Demerol)
- butorphanol (Stadol)
- nalbuphine (Nubain)
- fentanyl (Sublimaze)
- pentazocrine (Talwin)
- pentobarbital sodium (Nembutas) – less common
- propofol – a common drug, but not recommended for IV sedation as it is easy to overdose
As with oral sedatives, there are reasons why a doctor or dentist would take extra care when prescribing these drugs, and theses are similar to those of taking diazepam or midazolam orally above.
General Anesthetic (GA)
(While not strictly a sedation in some circles, this is included for completeness)
General anesthetic involves being given a series of drugs either by inhalation, intravenous injection, or both, and sometimes with oral premedication. Different stages gradually move the patient to a situation where they feel no pain, all natural reflexes are inhibited (including breathing) and all muscles relax.
General anesthetics are now only performed in hospitals with proper monitoring of vital systems and full medical backup. It is now less common to be given a general anesthetic for dental work, but there remains a hard core of patients for whom there is no other option.
- complicated wisdom tooth removal
- extremely uncooperative children or children who require extensive dental work
- adults with severe learning disabilities
- other highly complex surgery or surgical reconstruction
There are three main stages to a general anesthetic:
1. Premedication This is a drug which can be given before the start of the operation and is to calm patients at an early stage. Drugs used include midazolam, melatonin and clonidine among others.
2. Induction Most GA regimens have a different method of inducing anesthesia to the one used during the operation itself. The stage is defined as when the patient has been given anesthetic medication but is not yet asleep. The following drugs are the most common for induction, and all but the last are given intravenously:
- propofol (also used for maintenance of GA)
- sodium thiopental
- sevoflurane (for inhalation induction)
3. Maintenance This is the stage where the patient is fully asleep and the operation proper can begin. There are a very large number of drugs which can be used for this stage, some injected, some inhaled through a mask.
The most common drugs used for GA are:
- propofol This is a very common GA drug although is usually mixed with others as it has no analgesic (pain-killing) properties.
- fentanyl This is usually used alongside propofol as it has strong analgesic properties 100 times more powerful than morphine.
The disadvantages and cautions of propofol and fentanyl include;
- the main contraindication of these drugs is known intolerance / allergy to these or similar compounds
- they cannot be used in patients with Chronic Obstructive Pulmonary Disease and some other respiratory problems
- some cases of muscle rigidity have been reported after use of fentanyl, although proper monitoring and access to respirators would mitigate adverse effects
- propofol has recently become more difficult to obtain due to manufacturing difficulties cited by one of the main manufacturers, and also possibly related to it’s licensing for executions by the state of Missouri.
- propofol was also administered to Michael Jackson at home by his doctor for 60 continuous days before the artist’s death in 2009.
Midazolam can also be used alongside fentanyl for maintenance.
Patients are often asked to stop taking all other medication before a general anesthetic and this is due to the extremely complex group of drugs given during GA. However, never do this of your own accord, always do as instructed by your health professionals.
Risks- There are, of course, many risks involved with receiving treatment under GA, but these are usually complications due to the treatment being undertaken (bleeding, blood-borne infection, organ failure) or due to pre-existing medical problems.
Risks from being the GA itself include breathing in stomach contents after vomiting and suffocation from insufficient oxygen.
There are a wide variety of choices when considering receiving dental treatment under sedation, and while each has its own benefit and advantage each carries its own risk as well. In most cases a procedure carried out by teams with proper training and experience should be trouble free and for the benefits which it can achieve for some patients is worthwhile.