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.
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.