The effect of hyaluronic acid addition to collagen in reducing the trismus and swelling after surgical extraction of impacted lower third molars: a split-mouth, randomized controlled study.

Background: Removal of impacted third molars is associated with postoperative complications such as pain, swelling, ecchymosis, trismus, infection, and hematoma. Thus, contemporary surgery aims to reduce complications by applying collagen or hyaluronic acid in the socket after extracting the impacted mandibular third molars. This study aimed to study the efficacy of hyaluronic acid (HA) addition to collagen, compared to collagen application alone, on the magnitude of swelling and trismus following impacted mandibular third molar surgery. Methods and materials: A total of 40 impacted molars of 20 participants who had completely bilateral impacted lower third molars were enrolled in this split-mouth, randomized, clinical trial. Randomization was carried out by two opaque envelops; two materials were applied topically in the socket collagen alone or with hyaluronic. The postoperative mouth-opening limitation and swelling rate were assessed on the third and seventh days after the extraction. Results: The mean age was 22.7 ± 3.079 years (75% female and 25% male). Regarding the rate of trismus, the test sides had less values than the control sides on 3rd days (44.03 ± 12.8 vs. 52.14 ± 13.7) and 7th days (19.22 ± 12.8 vs. 32.45 ± 15.3) postoperatively but the difference is only significant on the seventh day (P = 0.005). The swelling scores of the hyaluronic acid addition group were significantly lesser than those of the collagen alone group on the third and the seventh day (P < 0.05) except for the lateral canthus to the angulus mandibulae on the third day (P = 0.133). Conclusion: Adding hyaluronic acid to collagen could effectively reduce the severity of facial swelling and trismus following surgical extraction of impacted lower third molars. Statement of clinical relevance : Swelling and trismus are the most sequela following impacted third molar surgical extraction. This study showed that applying hyaluronic acid with collagen can reduce the severity of facial swelling and trismus which could be useful in surgeons' daily practice. We should mention that this original article has a preprint edition (44). [ABSTRACT FROM AUTHOR]