• Ratchanee Panjinda B.N.
• Oranart Matangkasombut D.D.S., Ph.D.
• Ruchanee Ampornaramveth D.D.S., Ph.D.
• Keskanya Subbalekha D.D.S., Ph.D. Diplomate Thai Board of Oral and Maxillofacial Surgery

Objective To conduct a preliminary survey of the prevalence of bacterial contamination on dental
anesthetic cartridges and to examine the antibacterial efficacy of alcohol for cartridge decontamination.

Materials and methods Bacterial culture of dental anesthetic cartridges collected from 25 dental
clinics in Bangkok was performed. Positive cultures were examined by Gram staining. The antibacterial
efficacy of 70% alcohol was tested against 3 bacterial species, Staphylococcus aureus, Pseudomonas
aeruginosa, and Bacillus subtilis. Anesthetic cartridges inoculated with bacterial cultures were
immersed in 70% alcohol for 1, 5, and 10 minutes, and subsequently transferred to culture medium.
The leakage of alcohol into cartridges was examined after immersing the cartridges in 70% alcohol
with 5% crystal violet for 10 minutes.

Results Bacterial contamination on dental anesthetic cartridges was observed in 32% of the clinics
examined. Gram positive bacilli, Gram positive cocci, and mixtures of Gram positive cocci and Gram
negative bacilli were found at 50%, 41.7% and 8.3%, respectively. Immersion of contaminated
cartridges in 70% alcohol for 10 minutes was effective in decontaminating Staphylococcus aureus and
Pseudomonas aeruginosa, but not Bacillus subtilis. No significant leakage of alcohol into the content of
the cartridges was found.

Conclusion Bacterial contamination on dental anesthetic cartridges is common. Immersion of
cartridges in 70% alcohol for 10 minutes is an effective decontamination procedure against Staphylococcus
aureus and Pseudomonas aeruginosa, with minimal risk of alcohol leakage into the content.

(CU Dent J. 2014;37:59-68)