Blood reflux into cartridges for dental anesthesia: detection in residual solution

The study examines blood reflux into cartridges under infiltration anesthesia. When imitation examination was carried out using Pontamine blue dye solution in 7 kinds of syringes using cartridges, dye reflux was observed in all of them. Dye reflux was observed in all but 1 of 4 kinds of cartridges on the market. The amounts of protein in residual anesthetic solution of cartridges after infiltration anesthesia were quantitatively measured by a dye binding method. Human hemoglobin was also measured by enzyme immunoassay (EIA). The detection rates of protein and human hemoglobin were 26.2% (85/324) and 24.2% (24/99), respectively. Study results show that blood reflux cannot be avoided in the cartridge system so reuse of residual anesthetic solution from cartridges should be prohibited as quickly as possible to avert risk of cross-infection of HB and AIDS virus.