Effect of Betamethasone Injection Into the Pterygomandibular Space on Postoperative Sequelae of Impacted Lower Third Molar Surgery: A Randomized, Double-blind, Placebo-controlled Clinical Trial With a Split-mouth Design

A prospective, single center, double-blind, randomized controlled design study was conducted between January 2022 and February 2023, in the department of oral and maxillofacial surgery, Rizgary teaching hospital, Erbil, Iraq. The participants were patients presented for the surgical removal of bilateral symmetrical impacted lower third molars. To achieve 95% power, a sample size of 40 patients with bilateral impacted third molars was required.

The study was approved by the Ethical Committee of the institutional board and was conducted in accordance with the guidelines of the World Medical Association Declaration of Helsinki (1964) and its seventh amendment (2013) and to the Consolidated Standards of Reporting Trials (CONSORT) (Figurec1). The objectives of the study, as well as the risks and benefits were explained to the patients and those who agreed to participate have signed a consent form.

The inclusion criteria of the study were: individuals of both genders aging between 18 and 35 years, classified as ASA I according to the American Society of Anesthesiologists, and who have symmetrical bilateral impacted mandibular third molar detected by a panoramic radiograph. Impacted teeth categorized as mesiaoangular (Winter classification) and class II position B (Pell and Gregory classification) were included. The patients had no infection, pain, trismus, and swelling at the time of surgery.

Patients who are smokers, with pericoronitis, active infection, systemic disorders, on long term steroids, pregnant and lactating women were excluded. Patients were also precluded if they had taken analgesics 24 hours before- and antibiotics one week before the surgery, and if the surgical procedure exceeded 30 minutes or if more than three cartridges of local anaesthesia were used during the procedure.

By implementing the split mouth model, each participant underwent two surgical procedures, with an interval of at least 4 weeks between them. Prior to the first procedure, randomization of the first side to be operated (right or left) was performed using the "heads or tails" technique using a coin, where the head represented the right side and tails the left side.