1.7 mL is actually the minimum included amount for truth-in-advertising purposes. In reality they all contain a little more. Please see documentation and explanation from Dr. Ken Reed below, as well as the resources he sent us on this topic.
The email response included below was an email response to Dr. Travis Coulter (Xchart co-founder) from Dr. Ken Reed.
Dr. Reed, has written numerous textbooks about dental anesthesia and spends most of his time these days teaching: https://www.klrdmd.com
Explanation Email from Dr. Ken Reed:
---------- Forwarded message ---------
From: Ken Reed <klrdmd@gmail.com>
Date: Tue, May 31, 2022 at 9:04 PM
Subject: Re: Local anesthetic question
To: Travis Coulter <travis@xchart.com>
Dental cartridges are made in the same factory they have been for over 50 years. Nothing has changed. They should be considered as 1.8 mL. The reason they say 1.7 mL is because that's the “minimum volume” the cartridge will contain. Al Reader and others did a study where they measured cartridge volume and found that both lidocaine and articaine averaged 1.76 mL. (the last sentence before the discussion in the attached paper)
The change from 1.8 to 1.7 on the label started with articaine in the year 2000. It said back then, “minimum contents of each: 1.7mL". Eventually, they dropped the “minimum contents of each” part on the label. It is an FDA “truth in advertising” thing. You’re better off using 1.8 mL for calculations with respect to overdose.
—
Ken Reed
Attachments:
The relevant portion of the referenced paper:
Note the "minimum contents of each" denotation on the label.
