2.2. Exclusion Criteria 
endo-perio, AIDS, allergic, bleeding, carious lesion, necrotic, immunocompromised diseases, pain, Wong-Baker, tooth, systemic disorders, inferior alveolar block
DENTAL CARIES, BLEEDING, LOCAL INFILTRATION, AIDS, SMEAR LAYER, NECROTIC, PULP NECROSIS, STERILE, CAVITY
Patients were excluded from the study in the following cases Non-restorable teeth;Presence of endo-perio lesions;Teeth associated with an acute or chronic apical abscess;Teeth with chronic periodontitis;Teeth with anatomical difficulties, such as open apices;Teeth with calcified canals;Teeth with severe dilacerations;Teeth with internal/external root resorption;Teeth with occlusal interferences;Patients who were allergic to medications that were used in the study;Patients who were taking medicines that could influence pain perception;Patients that had serious medical illness;Patients with systemic disorders; andPatients with immunocompromised diseases such as AIDS or HBV.The participants were randomly assigned to four groups according to a simple random number table available online (All the cases were diagnosed and treated by a single endodontist with eight years of experience, under 3.5× magnification and using dental magnifying loupes (Univet Loupes, Rezzato, Italy). After confirming the eligibility, the offending tooth was anesthetized with 1.8 mL of 2% lidocaine, with 1:100,000 epinephrine (Octocaine 100, Novocol Pharmaceutical, Cambridge, ON, Canada) using the local infiltration (mandibular anterior/maxillary teeth) and inferior alveolar block (mandibular premolars). Rubber dam isolation was performed for each patient to prevent teeth contamination by saliva. The dental caries was removed followed by complete deroofing of pulp chamber. The size of the access cavities was not standardized and was dependent upon the size of the carious lesion. A diagnosis of pulp necrosis was confirmed at this step, and only those teeth showing no bleeding upon access preparation and a visibly necrotic, dark pulp tissue were included (ICD 10 Code K 04.1). The pre-endodontic tooth build-up was carried out with glass ionomer cement to ensure the proper isolation and inter-appointment sealing of the access cavity for cases in which access preparation extended to more than one surface. The glide path was prepared with stainless steel hand K-files, #06, #08, and #10 (Dentsply Maillefer, Switzerland). The working length was obtained by an electronic Apex locator (Dentaport ZX, J Morita, Kyoto, Japan) and verified by periapical radiograph. The root canal preparation was carried out to #20 (0.02 taper) with a hand K-file (Dentsply Maillefer, Switzerland). The Ni-Ti Rotary assorted files (Protaper Universal; Dentsply Maillefer, Switzerland) were then used to prepare the root canals using the crown down technique. Copious irrigation with 3% NaOCl was carried out. The canals were flooded with 17% EDTA solution (MD-Cleanser, Meta Biomed, Cheongju, Republic of Korea) for 3 min, post root canal preparation, to remove the inorganic component of the smear layer. 5 mL saline solution was used as the final rinse, and the canals were dried with sterile paper points (Dentsply Maillefer, Ballaigues, Switzerland). Intra-canal medicaments, using a Lentulo spiral, were placed according to the groups assigned to the patients in the random number table.Group 1 received CH (20%) as intra-canal medicament; Group 2 received CHX (2%) gel; Group 3 received TAP (ciprofloxacin, minocycline, and metronidazole mixture in a proportion of 1:1:1 by weight); Group 4 received no dressing (Control group).Excess medicaments coronal to the cementoenamel junction were removed with a moist cotton pellet, followed by placement of a sterile dry cotton pellet in the pulp chamber. Subsequently, the cavities were sealed with glass ionomer cement of minimum 3 mm thickness. The teeth were ground out of occlusion to prevent pain from occlusal forces. No medications were prescribed to the patients. Before dismissal, patients were instructed to record their pain intensity score on Wong-Baker’s FACES pain rating scale at 4, 48, 72, 96 hrs. Data were entered into an excel sheet and was later exported to SPSS. All analysis was carried out using SPSS version 24 (IBM, Armonk, NY, USA). The normal distribution of data was checked by creating histograms, and after confirmation, parametric tests were used. A one-way ANOVA test and Tukey’s post hoc test were utilized to perform multiple comparisons of pain scores between different groups at different time intervals. The level of significance was set at less than 0.05. Lastly, all the experimental groups were compared with the control group using Dunnett’s test.