Wisdom teeth removal is one of the most common surgical procedures performed, often requiring some form of deep sedation or general anesthesia. Patients must follow specific pre-operative instructions precisely to ensure a safe experience during the procedure. Understanding the exact rules regarding what can and cannot enter the body is paramount before the day of your appointment.
The Specific Rule Regarding Swallowing Saliva
The good news is that swallowing your own saliva is perfectly acceptable and does not violate the required fasting protocol. Saliva is a naturally produced bodily fluid, not an ingested food or liquid that needs to be withheld. The body continuously produces saliva, which is composed primarily of water, and swallowing it does not increase the volume of contents in the stomach in a problematic way.
The concern lies with intentional drinking or eating, which introduces external substances into the digestive system. Saliva is not classified in the same category as a drink of water or a sip of juice. It is important to avoid intentionally drinking water, even in small amounts, unless directed to take medication with a single sip by your surgical team.
Why Strict Fasting is Required Before Surgery
The requirement to fast before surgery is known as the NPO protocol, meaning “nothing by mouth.” Standard guidelines recommend an eight-hour fast for solid foods and heavy meals. This long timeframe ensures the stomach is empty of complex, difficult-to-digest particles. A shorter fasting period of six hours is often permitted for a light meal or non-human milk products, as these substances clear the stomach faster than fatty foods.
The most modern guidelines allow clear liquids—such as water, black coffee, or pulp-free juice—up to two hours before the scheduled time of the procedure. Adhering to these strict timeframes is necessary because the presence of any significant volume of food or liquid in the stomach creates a serious medical hazard once sedation is administered. Patients must also refrain from chewing gum or using hard candy, as these stimulate the production of gastric secretions.
Understanding the Danger of Aspiration
The medical reason behind the NPO rule centers on the danger of pulmonary aspiration, a rare but life-threatening complication. When a patient receives IV sedation or general anesthesia, the protective reflexes that guard the airway become significantly relaxed or temporarily inactive. These reflexes include the gag reflex and the tone of the lower esophageal sphincter, which acts as a muscular valve between the esophagus and the stomach.
If the stomach contains food or liquid, the relaxation of the esophageal sphincter can allow stomach contents to passively flow back up the esophagus and into the back of the throat. Since the protective reflexes are suppressed, these contents can then be inhaled, or aspirated, into the lungs. Aspiration of gastric contents can cause severe chemical pneumonitis or even bacterial pneumonia, as the highly acidic stomach fluid damages the delicate lung tissue. Ensuring the stomach is empty by following the NPO instructions is the primary way to reduce this serious risk.