John A. Yagiela, DDS, PhD, is professor and chairman of the Division of Diagnostic and Surgical Sciences at the University of California, Los Angeles, (UCLA) School of Dentistry and professor of Anesthesiology at UCLA School of Medicine. Yagiela authored a feature on anesthesia that appears in our May 2005 issue.

QUESTION Have you heard any discussion on the use of articaine possibly causing parasthesia if given for a block?

ANSWER Local anesthetics have the potential to damage nerve fibers. The effect is concentration dependent—the higher the concentration of local anesthetic present, the more likelihood that damage will occur. It is probable, but not proved, that injection within the nerve trunk promotes this rare adverse effect. The most likely reason is that the local anesthetic solution injected within the nerve trunk exposes the nerve fibers to a high concentration of drug for a considerable period of time. Attendant hydrostatic pressure and physical trauma from the needle may also contribute to the damage. Injecting outside the nerve sheath, as normally occurs, presumably results in considerably lower concentrations bathing the nerve fibers.

Some dental professionals inject a local anesthetic without a vasoconstrictor first for a mandibular block because administering the solution causes less pain than occurs with the more acidic local anesthetic with a vasoconstrictor. This initial injection may also numb the nerve trunk such that the patient can’t feel the second needle strike the nerve. Without the patient reacting, the clinician may think everything is fine and then proceed with an injection inside the nerve proper. I believe this practice contributes to the paresthesias that are being reported.

► Infection Control and Tattoos

John A. Molinari, PhD, is professor and chair of the Department of Biomedical Sciences at the University of Detroit Mercy School of Dentistry, Detroit. He is an editorial advisory board member for Dimensions of Dental Hygiene and a frequent contributor. The second installment of his series on avian flu will appear in the June issue. The first part is archived with the March 2006 issue here.

QUESTION I have heard that the new fad is intra-oral tattoos. How safe are they and what effects do they have on the oral cavity?  

ANSWER To look at this inquiry from an infectious disease perspective, the problem continues to be hepatitis B and hepatitis C cross-infection from contaminated needles. I don’t know if there are any data regarding the use of sterilizers in tattoo parlors but, in general, infection control precautions are not as stringent as in professional health care facilities. Coupled with the fact that the tattoo is placed in the “cesspool of the body,” you have a perfect site for secondary infection with staph or a variety of oral microbial mixtures.

► Power Brushing and Abrasion

Jill Rethman, RDH, BA, has been involved in dental hygiene for more than 30 years, from clinical practice to speaking to publishing. She currently serves as the editorial director for Dimensions of Dental Hygiene.

QUESTION Does the use of power toothbrushes cause recession and abrasion? 

ANSWER To my knowledge, the widely used power toothbrushes available on the market today have been tested to show they are gentle on the gums. However, any toothbrush (power or manual) can cause recession and/or abrasion if used improperly. For power brushes, patients need to follow the manufacturer’s instructions regarding use. Patients should also be instructed that only very light pressure is necessary with power brushes (especially sonic) because the bristles do the work for them.