Effects of Buffering and Preparation Time of Topical Anesthetics on Pain of Injection into Oral Mucosa

Abstract

Background: Many dental patients are afraid of injections. There are different methods for reducing pain during topical anesthetic injections. Some studies have reported buffering lidocaine to reduce injection pain. In this study, the effects of fresh and buffered topical anesthetic on injection pain were evaluated. Methods: In this prospective study, 4 groups of 20 dental treatment candidates were selected. Topical anesthetics for the 1st-4th groups included carpules of lidocaine/epinephrine, carpules of lidocaine/epinephrine/bicarbonate, freshly prepared lidocaine/epinephrine, and freshly prepared lidocaine/epinephrine/ bicarbonate, respectively. The initiation of topical anesthesia and injection pain were evaluated using a visual analogue scale (VAS). Findings: The highest and lowest mean scores of pain belonged to the carpule group (2.67 ± 0.28) and fresh lidocaine/epinephrine/bicarbonate (0.86 ± 0.37), respectively. While topical anesthesia started 2 minutes after injection in 95% of fresh lidocaine/epinephrine/bicarbonate group, the rate was as low as 50% in carpule group. Conclusion: Adding bicarbonate to carpules of lidocaine/epinephrine and fresh lidocaine/epinephrine is recommended to decrease injection pain and accelerate the onset of effect. Keywords: Bicarbonate, Dentistry, Local anesthesia, Pain