The aim of study was to evaluate the effect of dental operating microscope use on the healing outcome of non surgical endodontic treatment of maxillary molars.

Prior to treatment a thorough clinical and radiological examination was carried out. A thorough history was taken from each patient and written informed consent was taken after explaining the procedure, risks and benefits. Mature maxillary first permanent molar with diagnosis of periapical periodontitis (as confirmed clinically & by periapical radiograph) was chosen for the study. Fifty participants were randomly assigned to either the dental operating microscope group or to control group (without using dental operating microscope) for the treatment.

After administration of local anesthesia and rubber dam isolation of the involved tooth ; access cavity was prepared using carbide bur and refined using ultrasonic tip in both groups. In both the groups similar protocol for irrigation, obturation and post operative restorations was followed. Immediate post-operative radiograph was taken using preset exposure parameters and follow up clinical and radiographic examination was carried at 12th month.

Inclusion Criteria:

• Patient willing to participate in the study
• Age > 18 years
• Maxillary permanent first molar having apical periodontitis requiring primary endodontic treatment
• Radiographic evidence of periapical radiolucency (minimum size 2 mmx 2 mm) and a diagnosis of pulpal necrosis as confirmed by negative response to cold and electrical tests and absence of bleeding on entering the pulp chamber

Exclusion Criteria:

• Unwillingness of patient.
• Retreatment cases
• Presence of internal or external resorption ,root canal perforations during endodontic treatment and immature teeth.
• Periodontally compromised teeth
• Immunocompromised, diabetic, pregnant and hypertensive patients
• Vertical root fractures
• Teeth those are not suitable for rubber dam application