Sedation dentistry

Sedation dentistry uses a combination of techniques, ranging from nitrous oxide (NO₂) also called “laughing gas” or “happy gas” to general anesthesia, to relax a patient during surgeries or otherwise uncomfortable appointments. Nitrous oxide gas, delivered with oxygen acts as an NMDA receptor antagonist. Before and during dental work, patients breathe the odorless and tasteless nitrous oxide gas (“laughing gas” or “happy gas”) in through a mask, which can help to relax them. Nitrous oxide gas has a rapid anxiolytic/sedative/analgesic effect and is delivered by inhalation. Nitrous oxide gas doses may be titrated to achieve target effect. Afterwards, the effects usually disappear within five to ten minutes.

Sedation is a state of depressed consciousness. There are depths or levels of sedation that range from minor to major depression of consciousness. Whereas depression of consciousness is a continuum, with no clear boundaries between levels, three levels of sedation have been defined and are in common use: minimal, moderate and deep sedation. The target level of sedation is the level that is intended for the patient. The level of sedation can vary according to the drug, the dose, the patient and the stimulus of the procedure. The level of sedation varies over time due to two main factors: the change in the concentration of the sedation drug within the patient and the variation in the stimulation that opposes sedation.

Although most dentists are qualified to administer nitrous oxide (NO₂), other types of sedation require additional training, equipment and emergency supplies. And because a relevant qualification is required to perform these techniques, not every dental clinic will provide the service you’d like. For this reason, some may choose to contract qualified doctors or dentists to come to their office to perform sedation for their patients. It is essential you find a qualified professional(s) who is qualified and familiar with dental sedation guidelines.

Types of dental sedation

Nitrous oxide (NO₂) or Laughing Gas

Probably the most common form of sedation in the dental office is nitrous oxide or “laughing gas” / “happy gas”. Also called inhalation analgesia and used to alleviate pain when giving birth, according to the National Institutes of Health – nitrous oxide does not put you to sleep, and is effective at reducing your anxiety about a dental procedure. It is very safe and provided in most dental offices. Local injections of anesthesia, which are still used in combination with nitrous oxide, now see consistent effectiveness, and some are practically painless. Nonetheless, the nitrous oxide gas can be administered by a machine to further reduce the discomfort of the injection.

Nitrous oxide (NO₂) or Laughing Gas is safe as it is a combination of Nitrogen and Oxygen which are present in the air we breathe. Happy Gas never goes past 70% Nitrogen, of which there is 80% in normal air.

You can’t overdose on the nitrous oxide gas, as the mixture quickly leaves your body if you breathe in one or two breaths of ordinary air. There are no after-effects either, and you can drive a car after about 15 minutes. This is the most frequently used and safest sedation method used in dentistry.

Advantages of nitrous oxide inhalation sedation:

• Safe
• Rapid Onset
• Flexible duration can be used for any appointment length
• Absolute Control. It is easy to quickly control the level of sedation
• People recover quickly
• Very few side effects
• There is an analgesic effect (pain-free)
• You can return to normal activities immediately after the appointment

Enteral sedation

The next type of sedation comes in the form of a pill or liquid that you take orally. This is called enteral sedation. Like local anesthetics, oftentimes it is used in combination with nitrous oxide. You may still be awake, but not nervous about the dental work.

Twilight anesthesia or IV sedation

Twilight sleep anesthesia also known as a twilight anesthesia, “I.V. sedation”, “conscious sedation” or “zombie state,” is an anesthetic technique wherein the dental sedation drugs are directly injected into a vein, is characterized by insensibility to pain without loss of consciousness, induced by an injections of scopolamine–morphine mixture. Twilight sleep anesthesia allows patients to be sedated without completely losing consciousness. This technique will allow the dentist to provide a deeper sedation, although you will still be awake but less aware of the procedure. The process requires recovery time after you leave the office. You must have someone take you home after the procedure. During surgery or other medical procedures, the patient is under what is known as a “twilight state”, where the patient is relaxed and “sleepy”, able to follow simple directions by the doctor, and is responsive. Generally, twilight anesthesia causes the patient to forget the surgery and the time right after. It is used for a variety of surgical procedures and for various reasons. Just like regular anesthesia, twilight anesthesia is designed to help a patient feel more comfortable and to minimize pain associated with the procedure being performed and to allow the medical practitioner to practice without interruptions. Twilight sleep anesthesia is safe and effective for people who need minor surgery or a procedure to diagnose a condition.

There are four levels of sedation by anesthesia. Twilight anesthesia is level 2, also known as moderate sedation/analgesia or conscious sedation, a drug induced depression of consciousness during which the patient responds purposefully to verbal commands, either alone or accompanied with light physical stimulation. Breathing tubes are not required for this type of anesthesia. Some of the same drugs used in general anesthesia are also used for twilight anesthesia, except in smaller doses and in a bolus interval (a concentrated mass of a substance administered intravenously for diagnostic or therapeutic purposes). These drugs can be administered via gases, such as nitrous oxide (laughing gas), or intravenously, with drugs such as ketamine (pediatrics primarily, and infrequently in adults), propofol, and midazolam. Twilight anesthesia alone is not used to provide relief from surgical pain, therefore, it is always given in conjunction with a local or regional anesthetic. Additionally, IV sedation is frequently administered as a concoction of several agents including those previously mentioned for induction and maintenance of anesthesia, as well as a benzodiazepine (usually midazolam, but temazepam or flunitrazepam are also used via the oral route) and a narcotic/systemic analgesic such as demerol or fentanyl. As discussed in the levels of sedation by anesthesia, assistance with breathing tubes (endotracheal tube or laryngeal mask airway) are not generally used for this type of anesthesia.

Patients under twilight anesthesia are carefully maintained in a state of drowsy relaxation during their surgical procedure. It is common for patients to fall into a light sleep during this type of anesthesia. The medication for sedation is delivered intravenously, while the surgeon or anesthesiologist injects the area to be operated on with a local anesthetic (ie. numbing medicine) for pain. It is completely normal for people to remember being in the operating room while under twilight anesthesia, or to remember people talking to them while the procedure is occurring. It is also possible to have vivid dreams, and to recall them after the procedure. These are all normal with twilight anesthesia, yet many people remember nothing at all. You should not feel pain, however, during twilight anesthesia, because the area to be operated on will always be numbed by the surgeon. These numbing medications last anywhere from 1-6 hours.

As with any anesthetic, all of the patient’s vital signs are continuously monitored throughout the procedure, but a breathing tube is not required Conscious Sedation because the patient is responsive enough to continue breathing. The recovery period for twilight anesthesia is usually very brief, and many patients feel better after this type of sedation than with general anesthesia.

IV Sedation indication

Patients that are suitable for IV sedation include those who:

• are anxious or have a fear/phobia of dental procedures
• have had bad experiences in the past
• require complex dental treatments
• have difficulty getting numb with local anesthetic
• have a strong gag reflex
• have a needle phobia

Types of procedures (under IV sedation)

• Dental fillings
• Cleans
• Extractions (including complex surgical extractions)
• Wisdom Teeth Extractions
• Dental Implants
• Veneers/Crowns
• Emergency Procedures
• Pain Relief

IV Sedation contraindications

There are some relative contraindications where we won’t be able to provide IV sedation.

These include:

• Pregnant patients
• Age below 15
• Diagnosed Obstructive Sleep Apnea
• BMI (body mass index) greater than 40
• Unstable medical conditions

IV Sedation side effects

IV sedation or twilight sleep anesthesia is usually safe. A very small minority of patients have dream-like recollections of the experience but these are not distressing. IV sedation is generally well tolerated, with transient side-effects which can include dizziness and nausea. However, if you are given too much of the medicine, problems with your breathing may occur. A doctor will be watching you during the whole procedure.

Your doctors always have special equipment to help you with your breathing, if needed. Only certain qualified health professionals can provide twilight sleep anesthesia.

Some common side effects of twilight sleep anesthesia may last for a few hours after the procedure, including:

• drowsiness.
• feelings of heaviness or sluggishness.
• loss of memory of what happened during the procedure (amnesia)
• slow reflexes.
• low blood pressure.
• headache.
• feeling sick.

General anesthesia

General anesthesia is a form of sedation by which you will be asleep for the entire procedure. It is practiced using drugs that are directly injected into a vein, along with the possible inhalation of a gaseous anesthetic. A thorough recovery time in the office may be required before leaving.

When you come in for your dental procedure, it usually takes about 20 minutes for an anesthetist or trained dentist to put in the IV line and administer sedation. Anesthetic cream can also be used beforehand on your skin to reduce the sensation of the IV line being put in.

During the dental procedure, professionals constantly monitor blood pressure and measure your pulse and oxygen. If you’re having several different procedures, the sedation may be adjusted, with more being used during extraction and less being used for a dental filling.

After a short period of recovery, you’ll be awake and can get up and walk around. But if you sit down or rest, you could very quickly fall asleep again. For this reason, patients shouldn’t drive or use heavy equipment after twilight sedation and should have someone with them at home after the procedure.

General anesthesia indications

Most of dental procedures can be performed under local anesthesia which is safe in nature. Decisions regarding general anesthesia can only be made according to each patient’s condition, but its use in dentistry should be restricted to ¹⁾:

1. Acute infection such as acute dento-alveolar abscess and severe pulpitis, which preclude to achieve appropriate local anesthesia, and pain relief during dental treatment. Meanwhile, in these circumstances medications or drainage procedures are failed due to local change in pH and a risk of spreading infection;
2. Small children who may not tolerate dental procedures under local anesthesia or those who experienced failures of previous attempts using local anesthesia constitute a majority of outpatient general anesthesia in dentistry. It is recommended that administration of general anesthesia to very young children be accomplished only by pediatric anesthetists;
3. Mentally compromised patients are unlikely to allow safe completion of treatment under local anesthesia because of problems related to physical/mental disability; therefore they might need general anesthesia;
4. Dental phobia: patients suffering from long-term dental phobia are best managed under general anesthesia in the first visit with the aim of gradual shift to local anesthesia, conscious sedation and behavior management techniques respectively;
5. Allergy to local anesthetic ingredients mostly the preservative methyl paraben can cause allergic reactions, which should be differentiated with vasovagal attacks;
6. Extensive dentistry and maxillofacial surgery: local anesthesia is unable to provide pain relief in an alert patient during extensive procedures ²⁾.

General anesthesia complications

D’Eramo et al. ³⁾, in studies demonstrated that the most common complication related to dental anesthesia was syncope (up to 80%) followed by laryngospasm, phlebitis, dysrhythmia, bronchospasm, and hypotension. Death was one of the most crucial side effects of anesthesia in dentistry most commonly caused by hypoxia according to Tomlin PJ ⁴⁾. Hypoxia can mimic a syncope attack with a low blood pressure, and a low cardiac output state with severe bradycardia ⁵⁾. According to review of the literature, the mortality rate associated with dental office anesthesia has been estimated to be between 1:1639 to 1: 1,733,000 ⁶⁾.