The study is designed as a randomized parallel controlled trial with three groups. Participants aged above 18 years with the first permanent molars with symptomatic signs of irreversible pulpitis will be randomly assigned into 3 groups. The first group (experimental group) will be injected with 4% articaine 1:100.000 epinephrine (inferior alveolar nerve block) will be anesthetized using 4% articaine 1:100.000 plus cryotherapy application, and the second group (experimental group) will be anaesthetised with IANB plus buccal infiltration. For the third group (control group), the mandibular molars will be anaesthetized using epinephrine using the inferior alveolar nerve block.

Inclusion Criteria:

• Patients aged above 18 years
• Presence of at least one mandibular first permanent molar, with signs and symptoms of irreversible pulpititis

Exclusion Criteria:

• Participants with a history of taking medications that could interfere with the action of the anaesthetic solutions
• Presence of paresthesia
• Presence of psychological problems
• Taking analgesics or other medications that would alter the inflammatory response of the pulp or provide analgesia 12 h pre-operatively