Types of anaesthesia in dentistry
Fear of pain is one of the basic reasons for anxiety before a visit to the dental practice. The history of the fight against pain reaches back to the 19th century, when nitrous oxide, i.e. "laughing gas", was first tried during a tooth extraction. Today, the progress of medicine makes it possible to practically completely abolish the sensation of pain during procedures. The variety of methods makes it possible to match the type of anaesthesia to the patient's needs. Classically, anaesthesia is divided into two large groups: general and local. In dentistry, local anaesthesia is used more often, eliminating the sensation of unpleasant experiences in a defined, relatively small area. Anaesthetic preparations, besides eliminating pain, contain an addition of substances that constrict the blood vessels, which limits bleeding and prolongs the action time of the agent.
Local anaesthesia
Among local anaesthesia one can distinguish a gradation of switching off the sensation of pain. The simplest, completely non-invasive, is surface anaesthesia – applied to the mucosa in the form of a gel or spray, without the use of a needle and syringe. It has drawbacks, however: a short time and a weak effect. It is sometimes used for minor procedures (e.g. removing a loose milk tooth) and to abolish unpleasant sensations during needle insertion in classic anaesthesia.
The second type is infiltration anaesthesia, consisting of saturating the tissues surrounding the tooth with an anaesthetic agent. It is most often used in dentistry – during the treatment or removal of upper teeth and lower front teeth. A needle and syringe are necessary to perform it. In most cases it is sufficient, but procedures on the lower lateral teeth and extensive treatment in the area of the upper teeth require conduction anaesthesia. It has a much larger area of action: the agent is administered in the area of the course of the nerve trunks (for the mandible – at the point where the inferior alveolar nerve enters the mandibular canal), which switches off sensation in the whole area supplied by that nerve. It causes numbness not only of the lower teeth on the given side, but also of the lip, cheek and half of the tongue. The action time varies individually.
Computer-controlled anaesthesia
A variety of local anaesthesia is computer-controlled anaesthesia – a solution for anxious patients who are afraid of the administration of the agent itself. Software designed so that the unpleasant sensations are minimal is responsible for the process of administering the fluid. The speed of administering the preparation is key here – because the process takes a long time and the speed is low, the patient does not feel the unpleasant pressure in the tissues. It is not, however, needle-free equipment: the doctor still has to insert the syringe in the appropriate place, but the needles used are smaller than those used classically.
The comfort of anaesthesia and sedation
Performing procedures under local anaesthesia ensures comfort and the absence of pain in most patients. There are, however, people for whom a visit is associated with such great stress that, despite anaesthesia, treatment is not possible – usually children or disabled patients, as well as adults with significant dentophobia. Such patients should be treated after prior premedication, under nitrous oxide sedation or general anaesthesia. These methods are more complicated and should be preceded by a consultation visit with a treatment plan.
The least invasive process of sedation is premedication – administering to the patient an agent, most often in the form of a tablet (sometimes intramuscularly), 30–60 minutes before the visit. The preparations used include, among others, diazepam, phenobarbital, hydroxyzine and the most frequently used midazolam. Oral premedication helps to control anxiety in both adults and children, but it does not guarantee the cooperation required for treatment.
Inhalation sedation and general anaesthesia
Another possibility is inhalation sedation, i.e. the use of a mixture of nitrous oxide with oxygen. Inhalation of "laughing gas" relaxes and calms the patient and reduces the level of fear and sensitivity to pain. Verbal contact is maintained, although patients describe procedures performed during sedation as seeming distant. The downside is the need to use a special mask during inhalation.
The most advanced method is intravenous analgosedation, i.e. general anaesthesia. It must be performed by an anaesthesiologist and consists of the intravenous administration of drugs and the constant monitoring of the patient. It makes it possible to keep the patient under anaesthesia for even 2–3 hours, to quickly reverse the action of the drug and to dose individually. Appropriate preparation is necessary before the procedure: additional tests (e.g. a blood count), taking into account concomitant diseases and medications being taken; the patient comes fasting, with an accompanying person, and gives written consent. After the procedure they remain under observation for 30–60 minutes, then should not drive vehicles or consume alcohol. General anaesthesia is a solution for uncooperative children, adults with dentophobia, disabled people and for extensive surgical or implant-prosthetic procedures.
Choosing the anaesthesia method
The availability of forms and types of anaesthesia used in dentistry is very great, which is why it is always possible to match the method to the individual case. Today, pain at the dentist need not be a reason for concern – the variety of methods allows for comfortable procedures, and the decision on the choice of anaesthesia is made by the doctor together with the patient.
Studies
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Efficacy of computer-controlled local anesthesia delivery system on pain in dental anesthesia: a systematic review of randomized clinical trials
Altuhafy M., Sodhi G. S., Khan J. (2024) · Journal of Dental Anesthesia and Pain Medicine · systematic review of randomised trials
Computer-controlled local anaesthesia usually reduced the pain felt during delivery in children compared with the traditional method. Differences in anxiety and behaviour were less clear-cut.
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Pain perception following computer-controlled versus conventional dental anesthesia: randomized controlled trial
Attia S., Austermann T., May A., Mekhemar M., Conrad J., Knitschke M., Böttger S., Howaldt H. P., Riad A. (2022) · BMC Oral Health · randomised controlled trial
Computer-controlled delivery of local anaesthetic reduced pain during the injection and during delivery compared with a traditional syringe. The technology can help anxious patients but does not replace conversation and good technique.
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Pregnancy outcome after in utero exposure to local anesthetics as part of dental treatment
Hagai A., Diav-Citrin O., Shechtman S., Ornoy A. (2015) · The Journal of the American Dental Association · prospective cohort study
Exposure to local anaesthetics during dental procedures in pregnancy was not associated with more frequent major birth defects or other adverse outcomes in this cohort. Standard assessment of the indication and of the patient's condition is still needed.