Comparing the postoperative flare ups and pain after adding the XP Endo Finisher to the final irrigation protocol on necrotic mandibular premolars.

patients are randomized into 2 groups after meeting the eligibility criteria,

1. Each patient will be given pain scale chart in order to record his /her pain level before any intervention.
2. The tooth is anesthetized, accessed and mechanical instrumentation to be made 3 A) For the experimental group: The canals will be thoroughly irrigated using 3ml syringe of 2.5% Sodium hypochlorite between every subsequent instrument. XP Endo finisher is used after the last instrument in preparation

B) For the control group :

The canals will be thoroughly irrigated using 3ml syringe of 2.5% Sodium hypochlorite between every subsequent instrument.

4) Obturation is done and postoperative instructions are given to the patient

Inclusion Criteria:

i. Age between 18-50 years old. ii. Males or Females. iii. mandibular Premolars

• Asymptomatic.
• Non-vital response of pulp tissue (negative response).
• With or without periapical radiolucency.

Exclusion Criteria:

i. Patients allergic to penicillin. ii. Pregnant females. iii. Patients having significant systemic disorder. iv. If antibiotics have been administrated during the past two weeks preoperatively.

v. Patients having bruxism or clenching. vi. Teeth that have :

• Vital pulp tissues.
• Association with swelling
• Acute peri-apical abscess
• Periodontally affected teeth
• No possible restorability
• Previous endodontic treatment.