Microbial factors and host inflammatory response deleteriously affect the periapical tissues, resulting in the formation of periapical (PA) lesions. Though majority of the periapical lesions heal subsequent to meticulous non-surgical endodontic treatment, iatrogenic errors like inadvertent sealer extrusion could jeopardize healing. Previous studies have highlighted the inflammation-inducing potential of epoxy resin root canal sealer (AH Plus, Dentsply, DeTrey GmbH, Konstanz, Germany) following its extrusion into the periapical tissues. Sealer-induced cytotoxicity results in the induction of an inflammatory response, which in turn causes periapical destruction, alveolar bone resorption, and even loss of tooth. There is a constant search for a biocompatible sealer that is less toxic or nontoxic and less irritating to the periapical tissues. The addition of antioxidants such as N-acetyl L-cysteine and peroxisome proliferator-activated receptor gamma agonists to epoxy resin-based sealers has been shown to reduce oxidative stress and inflammatory reaction induced by these sealers.

Another bio-pharmacologic agent that was found to be effective is pachymic acid (PA), a triterpenoid, extracted from the fruiting body of Fomitopsis nigra mushroom, known to possess anti-inflammatory property. Kim et al, 2013 demonstrated that the antioxidant effect of PA restored cell viability and alkaline phosphatase activity in mouse osteoblast (MC-3T3 E1) cells exposed to AH Plus. Arun et al, 2017 reported that incorporation of PA to AH Plus significantly reduced the cytotoxicity associated with the latter, when tested on L929 mouse fibroblast cells. Preethi et al, 2020 reported that AHP/PA exhibited physicochemical properties that were within the requirements of ISO and with time, showed apical sealing ability that was comparable to AH Plus. But the effect of the addition of PA to AH Plus on periapical healing in teeth with periapical lesions under in vivo conditions has not yet been explored.  

Root canal sealers can play a crucial role when in contact with the periapical tissues causing a localized inflammation with a direct influence on the degree of inflammation based on the composition of the sealer in turn influencing postoperative pain levels. Imaging forms an essential part of endodontics, from diagnosis to long-term assessment of healing outcomes. Studies have referred to the periapical index (PAI) as a scoring system for radiographic assessment of periapical lesions. The PAI represents an ordinal scale of 5 scores ranging from no disease to severe periodontitis with exacerbating features. Hence the benefit of using radiograph with a PAI index in endodontics corresponds to a high accuracy in detecting periapical lesions even in its earliest stages and aiding in differential diagnosis as a non-invasive technique. Postoperative pain usually ranges from 3% to 58% based on the individual’s pain perseverance and stimulus and is considered to be a significant clinical outcome exhibiting a multifactorial response to treatment related factors including the type of endodontic sealer used for obturation. Hence, the aim of this observational study is to evaluate the periapical healing following root canal treatment of single rooted permanent teeth with periapical lesion using pachymic acid modified epoxy resin root canal sealer.