Evaluation of the effect of submucosal dexamethasone injection on pain in patients undergoing third molar removal: a randomised controlled trial

Objectives Third molar removal is one of the most common oral surgery procedures performed in Ireland. Pain, swelling and trismus are well-documented, undesirable consequences following third molar removal. These sequelae have a negative impact on the patients’ quality of life post-operatively. We aimed to compare the effect of a submucosal injection containing 4mg dexamethasone on the post-operative pain experienced by the patient versus a control of standard surgical removal of a mandibular third molar on the contralateral side. We also analysed patient preference of treatment regime. Methods A randomised controlled trial was conducted involving 70 patients undergoing surgical removal of bilateral, symmetrically-impacted mandibular third molars under general anaesthetic in Cork University Hospital. Each patient acted as their own control in this split-mouth study, with all treatment carried out at one single visit. All subjects received standard local anaesthetic bilaterally in the form of inferior alveolar block and long buccal infiltration with 2% lidocaine with 1:80,000 epinephrine. The site randomised for intervention received a 1ml submucosal injection of 4mg dexamethasone in the buccal vestibule adjacent to the lower third molar following administration of local anaesthetic. Both the patient and investigator were blinded to the intervention site. The primary outcome measure of pain was self-reported and recorded by the patient for the right and left surgical site for seven days following intervention using a visual analogue scale. Results Pain and inflammation are normal physiological responses to tissue trauma such as surgery. The age range of the participants in the trial was 16 to 54 years of age, with the mean age being 22 years (SD 5.7 years) and median age 21 years. The study participants were comprised of 44 females and 26 males. We demonstrated that the reported pain scale (VAS 0-100mm) decreases moderately with the treatment intervention of 4mg dexamethasone as a submucosal injection (Estimate: -3.32, CI: -5.36 to -1.28, p < 0.01). Conclusion This trial demonstrated a minor but consistent improvement in analgesic effect when submucosal dexamethasone was administered in comparison to control supporting the alternative hypothesis. The effect size detected was minimal (estimated 3% improvement) and as such deemed not clinically meaningful for patients. Therefore, the routine use of submucosal dexamethasone injection in the extraction of impacted third molars should not be recommended