Document Type : مقاله‌های پژوهشی

Abstract

Background: Studies have shown that failure in achieving anesthesia in the posterior mandibular teeth with irreversible pulpitis is common. Different factors have been reported to be responsible for failure of anesthesia in such teeth. The aim of the current study was to evaluate the effect of tooth length on failure rate of inferior alveolar never block anesthesia in mandibular first and second molars. Materials and methods: In this random cross-sectional study 90 patient with their first and/or second mandibular teeth affected with irreversible pulpitis were evaluated. Inferior alveolar nerve block anesthesia procedure was carried out with 2% lidocaine with 1:100000 epinephrine. Heft-parker Visual Analog Scale (VAS) was used for evaluation of pain. Lip anesthesia and absence of response to maximum pulp tester provocation after 15 minutes was considered as anesthesia. Pain was scored before treatment, during access cavity preparation and after pulp exposure. Tooth length was measured with endodontic gauge on periapical radiographs (SPSS) Data were analyzed with repeated-measures ANOVA, t-test and regression analysis, using SPSS 21 (α=0.05). Results: The total failure rate of inferior alveolar nerve block injection was 62.22%. The mean tooth lengths in patients with successful and failed inferior alveolar nerve blocks were 21.45±2.04 and 23.05±2.43 mm, respectively (p value = 0.002). Conclusion: Under the limitations of the current study, it was concluded that tooth length might be a factor affecting the failure of inferior nerve block anesthesia technique.  Key words: Anesthesia, Mandible, Pulpitis, Tooth.