The aim of this study is effect of premedication on success of inferior alveolar nerve block injection. Sixty healthy adult volunteers including criteria, are participating. The patients will be divided into 3 groups and will be randomly given one of premedications including 1) 10 mg Ketorolac, 2) 10 mg Ketorolac plus 1000mg Acetaminophen, and 3)Placebo, 45 minutes before applying the injection. All patients will receive standard Inferior Alveolar Nerve Block injection . Patients with no lip numbness and positive responses to cold and electric pulp tests would be excluded from the study. Endodontic access preparation will be initiated 15 minutes after Inferior Alveolar Nerve Block injection. Pain during treatment will be recorded using a Heft parker Visual Analog Scale(VAS). Success will be considered as no or mild pain (VAS≤54) during caries/dentin removal, access cavity preparation and working lengths measurements. Data will be analysed using Mann-U-Whitney and Kruskal-wallis tests.

The aim of this study is effect of premedication on success of inferior alveolar nerve block injection. Sixty healthy adult volunteers with including criteria and with no spontaneous pain, reporting no or mild (Visual analog scale≤54) pain in response to cold testing and electric pulp tester, are participating. The patients will be divided into 3 groups on a random basis and will be randomly given one of the oral medications including 1) 10 mg Ketorolac, 2) 10 mg Ketorolac plus 1000mg Acetaminophen, and 3)Placebo, 45 minutes before applying the injection. All patients will receive standard Inferior Alveolar Nerve Block injection with one carpule of 4% Articaine with 1:100000 Epinephrine. Patients with no anesthetic sign (lip numbness) and positive responses to cold and electric pulp tests would be excluded from the study. Endodontic access preparation will be initiated 15 minutes after Inferior Alveolar Nerve Block injection. Pain during treatment will be recorded using a Heft parker Visual Analog Scale(VAS). Success will be considered as no or mild pain (VAS≤54) during caries/dentin removal, access cavity preparation and working lengths measurements. Data will be analysed using Mann-U-Whitney and Kruskal-wallis tests.

Inclusion Criteria:

• Patients with age ranged 18-65
• without systemic diseases
• without any medicine consumption
• non smoking
• non pregnant
• non breast feeding
• with asymptomatic irreversible pulpitis ( Visual Analog Scale ≤ 54) in one mandibular molar that needs root canal treatment
• without any medicine consumption or analgesic and sedation
• understand and sign the VAS and consent forms

Exclusion Criteria:

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