Aim

To examine the efficacy rate of four anaesthetic protocols in mandibular first molars with symptomatic irreversible pulpitis (SIP).

Methodology

One-hundred-sixty patients with a SIP diagnosis were included in this randomized clinical trial. Patients were randomly allocated into 4 treatment groups (N=40) according to the administered technique: Group 1 (IANB): standard inferior alveolar nerve block (IANB) injection; Group 2 (IANB + IO): standard IANB followed by a supplemental intraosseous infusion (IO) injection; Group 3 (IANB + PDL): standard IANB followed by a supplemental periodontal ligament (PDL) injection; Group 4 (IANB + BI): standard IANB followed by a supplemental buccal infiltration. Patients rated pain intensity using a verbal rating scale (VRS) when root canal treatment procedure was initiated, i.e. during caries removal, access preparation, and pulpectomy. Heart rate changes were recorded before, during and after each injection. The anaesthetic efficacy rates were analyzed using chi-square test, age differences using One Way ANOVA, gender differences using Fischer Exact test whilst heart rate changes were analyzed using Kruskal Wallis test. Statistical significances were set at P < 0.05 level.

Results

All the included patients were analysed. No differences in the efficacy rate were found in relation to the age or gender of the participants amongst the study groups (P >0.05). IANB+IO injections had a significantly higher efficacy rate (92.5%) when compared to other techniques (p<0.05), followed by IANB+PDL injections (72.5%), IANB+BI injections (65.0%), with no significant differences between the IANB+PDL or IANB+BI injections (p>0.05). IANB injection alone had a significantly lower rate (40%) compared to the other techniques (p<0.05). A transient but significant rise in the heart rate was recorded in 60% (24/40) of patients who received the IANB+IO injection compared to other groups (p<0.05).

Conclusions

IANB injection alone did not reliably permit pain-free treatment for mandibular molars with SIP. The use of an additional IO supplemental injection provided the most effective anaesthesia for patients requiring emergency root canal treatment for SIP in mandibular posterior teeth.