Intraoral Cryotherapy on Anesthetic Efficacy in Mandibular Incisors

Achieving profound pulpal anesthesia in mandibular anterior teeth with symptomatic irreversible pulpitis remains a significant clinical challenge. Inflammation within the pulp tissue lowers the pain threshold and alters the local tissue environment, reducing the effectiveness of conventional local anesthetic techniques. Buccal infiltration anesthesia alone may be insufficient in mandibular incisors due to accessory innervation and anatomical variations, often necessitating supplemental techniques such as lingual infiltration or intraligamentary injections. However, repeated injections may increase patient discomfort and anxiety, highlighting the need for effective, non-pharmacological adjunctive methods to enhance anesthetic success.

Cryotherapy is a non-toxic, non-pharmacological method that has been widely used in medicine for its anti-inflammatory and analgesic effects. Local cold application induces vasoconstriction, reduces nerve conduction velocity, and limits inflammatory responses, thereby potentially enhancing anesthetic efficacy. Previous studies have demonstrated that intraoral cryotherapy can improve the success of inferior alveolar nerve block anesthesia in mandibular molars with irreversible pulpitis. However, there is currently no clinical evidence evaluating the effectiveness of intraoral cryotherapy in improving infiltration anesthesia success in mandibular incisor teeth diagnosed with irreversible pulpitis.The present randomized clinical study aims to compare the anesthetic efficacy of intraoral cryotherapy and supplemental lingual infiltration when used in conjunction with buccal infiltration anesthesia in mandibular incisors with symptomatic irreversible pulpitis. Additionally, the study evaluates whether intraoral cryotherapy can serve as an alternative to supplemental lingual infiltration for improving anesthetic success. The study also investigates the effect of vasoconstrictor-containing and vasoconstrictor-free local anesthetic solutions on anesthetic outcomes.

Eligible participants diagnosed with symptomatic irreversible pulpitis in mandibular central or lateral incisors are randomly assigned to one of seven experimental groups receiving different combinations of buccal infiltration, lingual infiltration, and intraoral cryotherapy, with or without vasoconstrictor-containing anesthetic solutions. Pain levels are assessed using a combination of Numerical Rating Scale (NRS) and Wong-Baker FACES scale during anesthetic administration and endodontic treatment procedures. Anesthetic success is determined based on patient-reported pain levels, electric pulp testing results, and the need for supplemental anesthesia. Additionally, thermal imaging is used to evaluate temperature changes in oral mucosa following anesthetic and cryotherapy applications, providing objective data on vasoconstriction and tissue response.

This study is expected to provide clinical evidence regarding the effectiveness of intraoral cryotherapy as an adjunctive method for improving anesthetic success in mandibular incisors with irreversible pulpitis. The findings may contribute to the development of safer, less invasive anesthetic protocols that improve patient comfort and reduce the need for multiple injections during endodontic emergency treatment.

Inclusion criteria

• Adults aged 18 to 60 years
• Classified as ASA Physical Status I or II
• Presence of symptomatic irreversible pulpitis in a single-rooted mandibular incisor tooth
• Preoperative pain score ≥8 on the Numerical Rating Scale (NRS) and Wong-Baker FACES scale
• Positive response to cold test and electric pulp testing
• Absence of periapical pathology on preoperative periapical radiograph
• No analgesic intake within 6 hours prior to treatment
• Ability to understand and complete pain assessment scales
• Willingness to provide written informed consent

Exclusion criteria

• Age below 18 years or above 60 years
• Pregnancy
• Known allergy to local anesthetic agents
• Diagnosis of diabetes mellitus
• Presence of hypothyroidism
• Diagnosis of adrenal insufficiency
• Presence of Raynaud disease
• Uncontrolled diabetes (HbA1c >7%)
• Presence of periapical pathology detected radiographically
• Presence of sinus tract
• Presence of intraoral or extraoral swelling
• Teeth diagnosed with necrotic pulp
• Presence of referred pain from another tooth or anatomical structure