Evaluating the Effects of Hyaluronic Acid on Postoperative Outcomes in Impacted Mandibular Third Molar Surgery: A Split-Mouth Study

Background: This study evaluated the postoperative effects of hyaluronic acid (HA) on pain, swelling, and trismus following mandibular third molar surgery. Material and Methods: Thirty healthy patients with bilateral impacted mandibular third molars underwent two surgeries at 21-day intervals. In a split-mouth design, one extraction socket was treated with 0.2 mL of high-molecular-weight hyaluronic acid gel (Monovisc® [molecular weight ≈ 1.5–2.2 million Da]), while the contralateral socket received no additional treatment. Perioperative medications, including NSAIDs, were standardized for all patients. Data collection included postoperative pain, swelling (using Gabka and Matsumura’s method), analgesic consumption, and trismus (mouth opening) on designated days. Data were analyzed using the Mann–Whitney U and Wilcoxon signed-rank tests with Bonferroni correction (adjusted significance level: p > 0.0083). Results: The mean VAS pain scores on day 1 were 63.5 ± 22.3 in the HA group and 61.9 ± 12.5 in the control group, decreasing to 3.9 ± 7.6 and 3.3 ± 7.2, respectively, by day 7 (p > 0.0083). The maximum interincisal distance on day 7 was 45.9 ± 7.4 mm in the HA group and 43.5 ± 7.3 mm in the control group, showing a slight improvement (p = 0.002). Swelling, measured using the tragus–pogonion distance, was 164.6 ± 20.7 mm in the HA group and 166.3 ± 18.9 mm in the control group on day 7 (p > 0.0083). Analgesic consumption remained comparable across all postoperative days (p > 0.0083). No statistically significant differences were observed between the HA and the control groups at any evaluated time point. Conclusions: Hyaluronic acid application after mandibular third molar surgery demonstrated a slight improvement in trismus on day 7, but no significant long-term advantages in pain or swelling. While early postoperative improvements in trismus were observed, these findings require further validation. Additional studies are needed to explore HA’s potential clinical applications in oral surgery.