Effect of Iontophoresis of 20%Lidocaine through Carious Dentine in Humans

Objective: The objective of this study is to evaluate the effectiveness of iontophoretic delivery of 20% lidocaine with 1:1,000 epinephrine for pain control during cutting the carious dentine in the dental patients. Methods: The experiments were carried out on 59 molars that had occlusal caries in 42 subjects (aged 15-20 yr., means 16.7 yr.). The teeth were isolated with composite resin wall and soft caries were removed. The baseline pain sensation induced by drilling, probing and air blast was assessed on 10 cm Visual analogue scale (VAS). In group I, the cavity was filled with 20% lidocaine with 1:1,000 epinephrine. An iontophoresis device (Dentaphore-II model 611 D, Life-tech, Inc. USA) was used with current 0.1-0.2 mA for 2 minutes then pain assessment to all stimuli was done every 2 minutes. In group II, the experiments were performed exactly the same as group I, excepted distilled water was used. The criteria for categorized as successful was that the pulpal anesthesia was obtained when iontophoresis used no longer than 10 minutes. Results: In group I, the baseline pain and sensation cause by drilling, probing and air blast were 3.56±1.66, 0.54±1.02 and 1.33±1.74 cm respectively. After Iontophoresis of lidocaine with epinephrine application, the mean VAS scores from drilling were 2.46±1.74, 1.57±1.73, 0.85±1.43, 0.55±1.13, 0.2±0.59, 0.2±0.59 cm, probing were 0.27±0.70, 0.16±0.53, 0.07±0.32, 0.0±0.0, 0.0±0.0, 0.0±0.0 cm, air blast were 0.84±1.54, 0.50±1.04, 0.18±0.51, 0.14±0.48, 0.07±0.32, 0.07±0.32 cm respectively after 2, 4, 6, 8, 10, 12 min (P<0.05, 1 way RM ANOVA). The time produced pulpal anesthesia was 2-10 min and the success rate was 87.5% (49 of 56 teeth). In group II, distilled water application had no effect. Conclusion: It is concluded that iontophoretic delivery of 20% lidocaine with epinephrine with in 10 minutes causes pulpal anesthesia up to 87.5 %