effect of occlusal reduction on post-operative pain is evaluated after single visit root canal treatment in upper and lower molar teeth in patients with sypmtomatic irreversible pulpitis and apical periondontis

Inclusion Criteria:

1. Patient's age between 20-50 years with no sex predilection.

2. Medically free patients.

3. Patients suffering from symptomatic irreversible pulpitis with symptomatic apical periodontitis in maxillary and mandibular molars with:

   • Preoperative pain.
   • Vital pulp.
   • Sensitivity to percussion.
   • Occlusal contact with the opposing teeth.
   • Normal periapical radiographic appearance or slight widening in the periodontal membrane space.

Exclusion Criteria:

1. Pregnant females.

2. Patients having a significant systemic disorder.

3. Patients who had administered analgesics or antibiotics during the last 12 hours preoperatively.

4. Patients having bruxism or clenching.

5. Teeth having :

   • No occlusal contact.
   • No sensitivity to percussion.
   • Association with swelling or fistulous tract.
   • Acute or chronic peri-apical abscess.
   • Greater than grade I mobility.
   • Pocket depth greater than 5mm.
   • No possible restorability.
   • Previous endodontic treatment