Vol.:(0123456789) 1 3 Clinical Oral Investigations https://doi.org/10.1007/s00784-023-04864-z RESEARCH Efciency of diode laser in control of post‑endodontic pain: a randomized controlled trial Hend H. Ismail 1  · Maram Obeid 1  · Ehab Hassanien 1 Received: 15 September 2022 / Accepted: 10 January 2023 © The Author(s) 2023 Abstract Objectives As post-endodontic pain control is one of the main targeted addressed in endodontics, our aim was delignated to compare two diferent methods for low-level laser application utilizing diode laser: low-level laser therapy (LLLT) and laser-activated irrigation (LAI) in the control of post-endodontic pain. Materials and subjects A total of 180 patients received single-visit root canal treatment; they were randomly allocated into 3 equal groups. Group I received LAI, group II received LLLT, and group III served as control with normal root canal treat- ment and mock laser intervention (ML group). Postoperative pain was recorded using visual analogue scale (VAS) after 24, 48, and 72 h. Data were tabulated and statistically analyzed. Results At 24 h, there was a statistically signifcant diference between median pain scores in the three groups (P value < 0.001) with ML group scored highest score followed by LAI and then LLLT group. At 48 h, there was a statistically signifcant diference between the three groups (P value < 0.001), with ML group scoring highest median pain scores while LLLT and LAI showed statistical insignifcant scores. At 72 h, there was no statistically signifcant diference between the 3 groups (P value = 0.179). Conclusion LLLT is superior to LAI and ML group in the control of immediate postoperative pain after 24 h while after 48 h both LAI and LLLT were equally efective, but they still showed signifcant diferences when compared to ML group. Clinical relevance Diode laser can be used by clinicians as it decreases the post-endodontic pain in patients with symptomatic apical periodontitis undergoing endodontic treatment. Keywords Low-level laser therapy · Postoperative endodontic pain · Laser-activated irrigation · VAS Introduction The control of postoperative pain is a golden target with mis- cellaneous tactics to achieve as it is a frequent sequalae after endodontic treatment and is accredited to either mechanical, chemical, or microbial aspects [1]. The usage of analgesics namely nonsteroidal anti-infammatory drugs (NSAIDs) is the most familiar way utilized to minimize this pain as they have a well-recognized pathway through the direct inhibition of cyclo-oxygenase enzymes 1 and 2 (COX) and infammation [2]. Although their analgesic property is well understood, NSAIDs have been accompanied with numerous adverse efects, such as gastrointestinal bleeding [3]. Laser therapy has been employed in dentistry widely since its development by Maiman in 1960 [4]. Its usage had a benefcial efect on pain relief [5] and wound healing [6]. With the rapid improvements in its technology and increased knowledge about its interactions with tissues (bio-interac- tion), the clinical uses of laser in endodontics are broader nowadays [7–9]. The commonest form of that is the use of diode laser in a low-level laser therapy (LLLT) and to acti- vate the root canal irrigants. LLLT reacts with cells through light, a phenomenon called photo-biomodulation [8, 10]. It was reported that this has anti-infammatory pain-relieving efect and considered as an aide to alleviate postoperative pains [5, 7, 11]. It was explained by the ability of low-level laser to modify pain threshold, lessen bradykinin, and histamine release, boost the formation of endogenous endorphins, and change pros- taglandin production [12, 13]. * Maram Obeid maramobeid@dent.asu.edu.eg 1 Dept of Endodontics, Faculty of Dentistry, Ain Shams University, Cairo, Egypt