How to Quickly Stop Tooth Pain

Benzocaine gels can successfully relieve toothaches

(RxWiki News) Toothaches should be examined by your dentist, but sometimes the pain is so strong that you may want temporary relief before your appointment. A new study proved that benzocaine gels can help.

Benzocaine gel is an over-the-counter anesthetic that is commonly applied on the skin, mouth and gums to relieve pain by numbing the tissue.

However, it was uncertain whether benzocaine can also be effective when applied on the exposed pulp in a tooth cavity. This study supported the efficacy and safety of benzocaine gels on improving toothache.

"Ask your dentist if you can benefit from benzocaine gels."

Elliot V. Hersh, DMD, MS, PhD, from the Department of Oral Surgery and Pharmacology, University of Pennsylvania, and other collaborators, recently investigated the efficacy of benzocaine gels to relieve the pain caused by a tooth cavity.

To prove the efficacy of benzocaine, 576 individuals were examined between the ages of 12 and 82 years with toothaches of at least moderate intensity caused by an open cavity.

The amount of pain experienced by each subject was estimated using a common measure called the visual analog scale — where the subject indicates their level of pain along a 100 mm horizontal line. No pain corresponds to zero. All subjects had at least a pain level of 50 mm, and their average pain level was 73 mm.

Researchers followed some of the patients that participated in the study, and they found that all of the individuals needed either a root canal or a tooth extraction.

The participants were randomly assigned to one of the three gels that they were told to self-apply to the affected tooth.

Ten percent benzocaine gel was assigned to 233 individuals, 20 percent benzocaine gel assigned to 229 individuals, and a sham gel (polyethylene glycol) was assigned to the remaining 115 individuals. It should be noted that one of the ingredients in the benzocaine gels is polyethylene glycol.

The results showed that 81 percent of the individuals in the group who used ten percent benzocaine gel and 87 percent of the participants in the group who used 20 percent benzocaine gel experienced pain decrease after applying the benzocaine gel — compared to 70 percent of individuals in the control group. 

However, the authors commented that one of the main limitations in this study is that the gel used as a placebo (the sham gel) was composed of polyethylene glycol, and they indicated that this substance also blocks pain. The article explained this as the reason that patients using the sham gel also reported an improvement (although less) in their toothache. 

The study didn’t investigate whether the location of the cavity, the severity of the pain (moderate or severe), or how many times a day the gel was applied had an influence on their results. Additionally, the study didn’t specify if the authors used statistical methods to compare differences in the results across groups.

The FDA has stated that methemoglobinemia is a rare but serious condition associated with the use of benzocaine. However, the authors noted that the dose necessary to decrease toothache is lower than the amount associated with risk of methemoglobinemia. The researchers commented that all the participants in this study tolerated the use of benzocaine gels well, and they didn’t observe problems.

Mark Bornfeld, DDS, who has run a private dental practice in Brooklyn, NY since 1977 and is editor at the Queens County Academy of General Dentistry, explained, “Methemoglobinemia is still considered an idiosyncratic side effect, and it may be difficult to predict the patients for whom the use of benzocaine products would be problematic. Another consideration is benzocaine chemical structure is similar to some allergens such as sulfonamides and thiazide diuretics, and topical application of allergens to mucous membranes is particularly efficient in provoking sensitivity in susceptible individuals.”
This study advised that benzoic gels should only be used during short periods of time in a dental emergency, and that the user should not delay in visiting a dentist. 
The authors concluded that benzoic gels can benefit individuals with toothache. But they didn’t recommend a specific concentration of the benzoic gel (ten percent or twenty percent) because even though the twenty percent benzoic gel appears to be slightly more efficient, its price is disproportionately higher than the ten percent gel. 
In his comments to dailyRx News, Mark Bornfeld said, “Although this study raises some interesting academic questions of dental pulp physiology, its failure to control for dosage in the experimental groups is a serious design deficiency. It is doubtful whether the conclusions of this study have any direct practical application, because there are already products on the market with lower risk potential.”
This study was published on October 10 in The Journal of Evidence-Based Dental Practice and was founded by Pfizer Consumer Healthcare, Madison, NJ and Church & Dwight, Princeton, NJ.
Review Date: 
October 20, 2013