Efficacy of anesthetic rice nanogel on pain reduction in human oral cavity

The aim of this study was to determine the efficacy of two local anesthetic rice nanogels (RNG) on pain reduction from needle insertion in oral cavity. Nanogel base was prepared using modified rice as gelling agent. The average particle size of RNG determined by photon correlation spectrophotometer was 485 ± 70 nm. Lidocaine hydrochloride (LH) and prilocaine hydrochloride (PH) were incorporated into RNG to obtain anesthetic RNG containing 5% and 20% LH or PH. Clinical efficacy test of each gel was performed in oral cavity of 100 healthy volunteers (25-60 years old). Evaluation was done by recording different pain measurements after inserting a needle into buccal mucosa after applying 5% and 20% anesthetic RNG. RNG base (placebo) and commercial anesthetic gels were used as negative and positive controls, respectively. It was found that the pain level in the negative control group was significantly higher than those of the anesthetic groups. Moreover, the pain level of the anesthetic RNG groups were lower than that of the commercial groups, especially in 20% anesthetic groups. For patient's satisfaction, most of the volunteers were appreciated with the anesthetic RNG as well as the commercial gels. They preferred to use high drug content RNG more than those with low drug content or placebo. It can be concluded that the anesthetic RNG has potential clinical efficacy in pain reduction during needle insertion in oral cavity.