Evaluation of Postoperative Pain and Bacterial Load After Hyalone or Calcium Hydroxide Medication in Mandibular First Molars

This randomized controlled clinical trial aims to evaluate the effect of Hyalone hydrogelcompared with calcium hydroxide as an intracanal medicament on postoperative pain andbacterial load reduction in mandibular first molars with necrotic pulp and symptomaticapical periodontitis. The rationale for the study is based on the important role ofintracanal medicaments in reducing residual microorganisms between treatmentappointments. Calcium hydroxide is widely used because of its antimicrobial activity andalkaline pH; however, it has limitations related to its distribution, adherence to canalwalls, antimicrobial spectrum, and effectiveness against microorganisms in complex rootcanal anatomy. Hyaluronic acid hydrogel has demonstrated potential benefits in dentistry,including supporting tissue healing and reducing inflammation and pain, and may thereforerepresent a promising alternative intracanal medicament.The study will include 28 patients, equally divided into two groups of 14 participants.Patients will be recruited from the Endodontic Department outpatient clinic at theFaculty of Oral and Dental Medicine, Future University in Egypt. Eligible participantswill be medically healthy patients aged 20‐40 years, with mandibular first molarsdiagnosed with necrotic pulp and symptomatic apical periodontitis. Teeth should haveclosed apices, be restorable, be sensitive to percussion, and demonstrate slight wideningof the lamina dura radiographically. Patients with systemic diseases, pregnancy orlactation, allergies to study medications, recent use of antibiotics or analgesics,swelling or acute apical abscess, open apices, vital pulp, periodontal mobility, previousroot canal treatment, or abnormal/calcified canal anatomy will be excluded.All participants will receive standardized endodontic treatment over two visits. Duringthe first visit, medical and dental histories, clinical examination, radiographicexamination, and preoperative pain assessment using the Numerical Rating Scale (NRS) willbe performed. Following local anesthesia, caries removal, access cavity preparation, andrubber dam isolation, working length will be determined using an electronic apex locatorand confirmed radiographically. The initial bacteriological sample (S1) will then becollected using sterile #15 paper points placed in the canal for one minute each. Thesamples will be processed microbiologically, and bacterial counts will be expressed ascolony‐forming units per milliliter (CFU/mL).Cleaning and shaping will then be performed using a crown‐down rotary instrumentationtechnique, with sterile saline irrigation between instruments. Following completion ofinstrumentation, a second bacteriological sample (S2) will be obtained to determine thereduction in bacterial load resulting from chemomechanical preparation. Patients willsubsequently receive either Hyalone or calcium hydroxide, according to their randomizedallocation. The medicament will be placed under aseptic conditions, and the access cavitywill be temporarily restored using glass ionomer.At the second visit after 7 days, the temporary restoration and intracanal medicamentwill be removed. The canals will be irrigated with sterile saline and a thirdbacteriological sample (S3) will be collected. This sample will allow assessment of theadditional bacterial reduction associated with the intracanal medicament. Followingsampling, the canals will be irrigated with 2.5% sodium hypochlorite and obturated usingthe cold lateral condensation technique with gutta‐percha and resin sealer. The teethwill then receive a final composite restoration.The primary outcome of the study is postoperative pain. Pain will be recorded using an11‐point NRS ranging from 0 (no pain) to 10 (pain as bad as could be). Patients willrecord their pain preoperatively and at 6, 12, 24, 48, and 72 hours and one weekfollowing treatment. Pain scores will also be categorized as none, mild, moderate, orsevere.The secondary outcome is the antimicrobial effect of the two intracanal medicaments.Bacterial samples obtained at S1, S2, and S3 will be analyzed using the serial dilutiontechnique, with bacterial counts expressed as CFU/mL. Samples will be processed underaerobic and anaerobic conditions to assess the cultivable bacterial population. Thechanges in bacterial load before instrumentation, after chemomechanical preparation, andafter intracanal medication will then be compared.The sample size was calculated based on a previous study, with a minimum required sampleof 11 participants per group. The number was increased to 14 participants