Among the words most commonly mumbled from a dentist's chair, "more Novocaine" surely must rank high. After all, anesthesia for basic dental procedures fails to numb in up to 40 percent of cases, studies have shown.
Now doctors have found that mixing dental anesthesia with mannitol, a simple sugar alcohol, greatly improves the pain-numbing effect that both patient and dentist so desperately crave.
As relayed in the current issue of the journal Anesthesia Progress, mannitol apparently helps to open the membrane that protects nerve fibers under the tooth, allowing the anesthesia to seep in. The mannitol helped reduce the pain of 40 subjects who were otherwise unfortunate enough to need three dental appointments to fix their teeth.
Best of all, mannitol, which is nearly identical to the sweetener sorbitol, is a safe and natural chemical found in fruits and vegetables and quickly passes through the body.
The most common anesthetic injection for basic dental work, such as fillings for molars, is the inferior alveolar nerve (IAN) block. The standard injection in the United States contains lidocaine and epinephrine.
Lidocaine is the anesthetic part; epinephrine is a vasoconstrictor that slows the absorption of lidocaine into the bloodstream, allowing it to linger around the tooth nerves for longer. The term novocaine often is used generically for dental anesthetics, but Novocaine, with a capital N, is technically the trade name for procaine, an anesthetic first synthesized in 1905 and not commonly used today.
In this study conducted by dental researchers from Ohio State University, 40 patients randomly received a different IAN block during three related visits to the dentist. One IAN block was the standard lidocaine-epinephrine mix; another was this plus about a milliliter of mannitol; and another was a higher volume of the lidocaine-epinephrine mix with the milliliter of mannitol.
Anything with mannitol lowered the pain sensation among patients. The mixture with a higher volume of lidocaine and epinephrine worked the best, although the pain relief wasn't uniform across the teeth, the subject for further investigation.
Lidocaine can cause dizziness, headaches, blurry vision and other adverse affects at concentrations higher than what was used in this study. Nevertheless, mannitol may allow dentists to use less lidocaine for even better results.
Unrelated to this dental work, adding powdered mannitol to standard therapy for cystic fibrosis produced sustained improvement in lung function for up to 52 weeks, according to a study to appear in the upcoming issue of the American Journal of Respiratory and Critical Care Medicine.
It all adds up possibly to 2012 being the year of mannitol, with apologies to the Chinese dragon.