Comparative Evaluation of the Effect of 970 nm Diode Laser With or Without N Acetyl Cysteine on Post Operative Pain After Endodontic Treatment in Teeth With Symptomatic Apical Periodontitis: a Randomized Clinical Trial

One of the most important aspect of endodontic treatment is management of postoperative pain management . Post operative pain after endodontic treatment is a frequent complication. frequency of post operative pain is between 3% to 58% .

Post operative pain could also occur as a result of inadequate instrumentation, extrusion of irrigation solutions, extrusion of intra-canal dressing, traumatic occlusion, missed canals, preoperative pain, periapical pathosis and extrusion of apical debris. Furthermore, instrument choice might also play an important role. The apical extrusion of infected debris during chemo-mechanical instrumentation of root canals might exacerbate the inflammatory response and cause peri-radicular inflammation.

The use of diode lasers, in addition to conventional endodontic therapy, has recently been proposed in RCT Various researchers have observed effective disinfection of the root canal by diode laser irradiation Due to the large water transmission capacities of diode lasers (810, 940 and 980-nm wavelengths), they can reach bacteria in deeper layers of dentinal tubules(3) Schoop et al. reported that using a 980-nm diode laser resulted in changes in dentinal surfaces and an increased bactericidal effect.

Other studies noted that laser irradiation decreases PP after RCT Over the years, studies have focused on identifying molecular mediators of inflammation induction, such as cytokines and chemokines in apical periodontitis. It was widely accepted that the loss of pro-inflammatory mediators was the 'turn off' signal of inflammation, ending subsequent responses passively.

Karapinar et al N-acetylcysteine (NAC) has been proposed as a potential alternative therapeutic agent in root canal treatment. NAC is an antioxidant mucolytic agent derivative of the amino acid L cysteine. As the precursor of glutathione, NAC can incorporate into cells and neutralize oxygen-derived free radicals (ROS), diminishing the cumulative effects of oxidative stress Previous studies have demonstrated the antimicrobial properties of NAC against several biofilm phenotypes, including oral pathogens such as Enterococcus faecalis, which is often found in endodontic infections. Moreover, NAC has been reported to exert anti-inflammatory activity by inhibiting the expression of lipopolysaccharide-induced inflammatory mediators.

Another study showed that the antibacterial effect of NAC is higher than that of NaOCl and CHX. More specifically, 200 mg/ ml solution of NAC was found to be more efficient than 5.25% NaOCl and 2% CHX in killing E. faecalis and S. mutant bacteria.(5) NAC exerts anti-inflammatory activity through its ability to inhibit the expression and release of a variety of proinflammatory cytokines. NAC can be a substitute for ibuprofen for post-endodontic pain. All these findings provide support for a superior potential for NAC in endodontic treatment.(6) Due to the scarcity of information on the effect of NAC as an intracanal medication, and the lack of systematic review on the same, this study aimed to compare and evaluate the post-operative pain when 970nm diode laser used with or without N acetyl cysteine as intracanal medicament

RESEARCH QUESTION : Will there be a difference in the postoperative pain after Endodontic treatment of mandibular molars with symptomatic apical periodontitis using 970nm diode laser with or without N acetyl cysteine ?

RESEARCH HYPOTHESIS (H1): There will be a difference in the postoperative pain after Endodontic treatment of mandibular molars with symptomatic apical periodontitis using 970nm diode laser with or without N acetyl cysteine

NULL HYPOTHESIS (H0): There will be no difference in the postoperative pain after Endodontic treatment of mandibular molars with symptomatic apical periodontitis using 970nm diode laser with or without N acetyl cysteine