Impact of maxillary teeth morphology on the failure rate of local anesthesia

To investigate the effect of maxillary single and multiple rooted teeth on the success rate of buccal infiltration anesthesia.

This clinical study was performed by dividing the participants into three groups. Group one included 30 patients with upper anterior teeth, group two 23 patients with upper premolars teeth and group three 39 patients with upper molars for extraction. Onset time of anesthtic action was evaluted by using electronic pulp tester. Pulp testing assessments were carried out immediately before the injection and at the intervals of 2 mins following the injection until the anesthetic success obtains.

Seventy-nine patients in this study secured anesthetic success within study duration time (10 min). However, there were 13 patients with dental anesthesia failures (3 patients with single rooted teeth and 10 patients with multiple rooted teeth). There were no significant differences in the mean onset time of pulpal anesthesia between the anterior, middle and posterior teeth (P value = 0.449). Clinically, patients with single rooted teeth reported faster dental anesthesia and earlier teeth extraction than patients with multiple rooted teeth.

This study showed that the single rooted teeth have faster pulpal anesthesia and early extraction than teeth with multiple roots but not statistically significant. Administration of extra local anesthetic cartridge or using intraseptal injection technique can be a solution to overcome the failure of anesthesia in the maxillary posterior teeth.