(PR75) Interaction Between 5.25% NaOCl and Local Anesthetic Agents

Introduction: Endodontic therapy often involves copious irrigation with 5.25% NaOCl. Additionally intrapulpal injections are frequently administered to provide additional anesthesia for patients. The interaction between the anesthetic solution has not been widely studied with only one previous study acknowledging a precipitate formed from this interaction. The purpose of this study was to provide additional analysis between 5.25% NaOCl and three commonly used anesthetic agents (2% lidocaine with 1:100k epinephrine, 4% articaine with 1:00k epinephrine, and 3% mepivicaine plain). Materials and methods: Samples were divided into four groups which involved 5.25% NaOCl added to saline or the previously mentioned anesthetic agents. The reaction was observed for 15 minutes and notes on color change and precipitate formation were recorded. The precipitate was then isolated and identified using mass spectrometry.

Results: All groups other than the control group (saline) formed a precipitate. The experimental groups exhibited a brown color change over the course of 15 minutes. The results of the mass spectrometry are still pending, but from a chemical standpoint are likely to contain 2,6-xylidine, as one previous study has identified.

Conclusion: A precipitate forming reaction occurs between 5.25% NaOCl and frequently used anesthetic agents. The toxicity and effects of these precipitates should be analyzed to indicate that the interaction of these solutions should be avoided.