Evaluation of the Success Rate of Pulpal Anesthesia in Mandibular First Molar Following Infiltration of 4% Articaine Alone and as Supplemental Injection After Inferior Alveolar Nerve Block

According to inclusion & exclusion criteria, volunteers will be selected and divided into 4 groups randomly. The clinician who does the injections will not be aware of study purpose. Also the person who does the electric pulp test (EPT); the volunteer and the statistical analyzer will not be aware of group codes. Intervention in each group will be as follow: Group 1-Buccal infiltration of one 4% Articaine cartridge with 1/100000 epinephrine. Group 2-Buccal infiltration of two 4% Articaine cartridges with 1/100000epinephrine. Group 3-Inferior alveolar nerve block using one 2% Lidocaine cartridge with 1/80000 epinephrine + buccal infiltration of one 4% Articaine cartridge with 1/100000 epinephrine. Group 4- Inferior alveolar nerve block using one 2% Lidocaine cartridge with 1/80000 epinephrine. Before injection a control tooth (contralateral canine) will be tested to understand the accuracy of patient's response to EPT; also for measuring the base line vitality, each tooth will be evaluated by EPT twice before injection. After injection each tooth will be evaluated by EPT every 3 minutes; also every minute the anesthesia of lip and tongue will be checked, up to 15 minutes. The tooth will be discerned "anesthetized" if the subject will not response to 80 reading of EPT in 2 consecutive tests. Finally the information will be recorded and in addition to the success rate the mean time for onset of anesthesia and its mean duration time will be evaluated.