Surgical extraction of impacted mandibular third molars often requires bone removal using rotary instruments, in which friction between the bur and bone generates heat. Excessive temperature rise may lead to local bone necrosis, delayed healing, and increased postoperative complications. Continuous irrigation with saline solution is routinely performed to reduce heat generation, and cold saline irrigation (0-4℃) has been shown to provide better thermal control than room-temperature saline.

This study aims to evaluate the effect of cold saline irrigation compared with room-temperature saline irrigation on postoperative outcomes following impacted mandibular third molar surgery. The assessed parameters include pain, swelling, trismus, and salivary C-reactive protein (CRP) levels as a biomarker of inflammation. Salivary CRP serves as a minimally invasive marker that reflects the systemic inflammatory response after surgery.

This randomized controlled trial will be conducted at the University of Medicine and Pharmacy at Ho Chi Minh City. Eligible patients with bilateral impacted mandibular third molars will be enrolled. Each patient will undergo extraction of one tooth with cold saline irrigation (0-4℃) and the contralateral tooth with room-temperature saline irrigation. Postoperative outcomes will include pain intensity (VAS) on days 1, 2, and 7; facial swelling on days 1, 2, and 7; trismus on days 1, 2, and 7; and salivary CRP levels at baseline and postoperative day 2.

The findings are expected to clarify the role of irrigation solution temperature in both subjective clinical outcomes and objective inflammatory markers, thereby providing evidence to optimize clinical protocols and reduce postoperative morbidity in third molar surgery.

Inclusion Criteria:

• Healthy patients with an ASA physical status classification of I or II.
• Patients with bilaterally impacted mandibular third molars of comparable difficulty, with an angulation difference between the two teeth not exceeding 15 degrees, confirmed by clinical and panoramic radiographic examination.
• Patients who have provided written informed consent after being fully informed about the study purpose and procedures.

Exclusion Criteria:

• Patients presenting with systemic or local acute inflammation or infection at the surgical site.
• Patients with systemic diseases contraindicating surgical tooth extraction.
• Patients with a history of corticosteroid or anti-inflammatory drug use within 3 weeks prior to participation.
• Patients with clinical or radiographic signs suggestive of tumors (benign or malignant) associated with or adjacent to the impacted mandibular third molar.