Is backflow possible when using a saliva ejector?

Backflow occurs when the pressure in the patient's mouth is less than that in the evacuator. When a patient closes their lips and forms a seal around the tip of the ejector a partial vacuum is created. Research suggests that in these situations previously suctioned fluids might be retracted into the patient's mouth. Furthermore, studies have shown that gravity pulls fluid back toward the patient's mouth whenever a length of the suction tubing holding the tip is positioned above the patient's mouth, or during simultaneous use of other evacuation equipment. The Centers for Disease Control and Prevention is not aware of any adverse health effects associated with the saliva ejector. However, in light of these findings, practitioners should allow the tubing to hang below the patient's head when the saliva ejector is in use, and avoid asking patients to close their lips around the tip of the saliva ejector. Suction lines should be disinfected daily. Dentists should contact the manufacturer of the dental unit to review proper use and maintenance, including appropriate disinfection methods.

Selected References and Additional Resources

American Dental Association. Statement on Saliva Ejectors. Available at http://www.ada.org/prof/prac/issues/statements/saliva.html *; INTERNET. Accessed August 2002.

Barbeau J, ten Bokum L, Gauthier C, Prevost AP. Cross-contamination potential of saliva ejectors used in dentistry. J Hosp Infect 1998;40:303-11.

Mann GLB, Campbell TL, Crawford JJ. Backflow in low-volume suction lines: the impact of pressure changes. J Am Dent Assoc 1996;127:611-15.

Watson CM, Whitehouse RLS. Possibility of cross-contamination between dental patients by means of the saliva ejector. J Am Dent Assoc 1993:124;77-80.