Study is a Randomized clinical trial conducted at Endodontic department- Ain Shams university Cairo. Egypt. 24 eligible patients were selected and included in the study to compare healing ability of soft tissue diode laser application versus conventional root canal treatment using CBCT

Sample size is 24 24 Patients were randomly distributed in 2 groups , one group of patients received soft tissue laser therapy after root canal treatment and the other group received no treatment just conventional RCT. • Patients were equally divided into 2 groups (n=12 in each group ) The study in a Single blinded RCT , Numbers for patients will be generated and distributed randomly in a table on an Excel sheet, and in front of each number either a letter (C) for control or (I) for intervention will be typed After patients were selected in the study they will be asked to fill in a consent form , that states that they are part of a clinical trial and that they may or may not have a laser session following root canal treatment Group A Soft tissue laser application : Endodontically treated teeth were targeted by virtue of a dental applicator positioned at a right angle to the mucosa at the level of the apices. Application of the laser probe were applied to both the buccal and lingual mucosae overlying the apices of the target tooth. Total exposure time for each tooth was 60 seconds (a dose = 70 j/cm2 for analgesia) by the co-investigator The laser unit used in this study will be a diode laser (Lite Medics 1.00 Watt serial number 148 Ver.SwvM. 150VS108VT.100) of wavelength 980nm and Max power 15 WCW Class IV Laser Product ) in continuous wave mode Group B : Placebo : conventional root canal treatment : mock laser intervention A CBCT was taken preoperative and after 12 month postoperative, both linear and volumetric measurements were calculated

Inclusion Criteria:

• Adult patients age between 18-50 years
• Medically free patients.
• Patients suffering from acute or chronic infection with symptomatic apical periodontitis with Necrotic pulp
• Preoperative Pain
• Sensitivity to percussion
• Periapical radiographic X-ray showing periapical lesion with no gutta percha in canal
• Occlusal contact with opposing teeth

Exclusion Criteria:

• Pregnant females.

• Patients having a significant systemic disorder or history of drug abuse

• Patients who had administrated analgesics or antibiotics during the last 12 hours preoperatively.

• Patients having bruxism or clenching

• Teeth having:

  • No occlusal contact
  • No sensitivity to percussion
  • Greater than grade I mobility.
  • Pocket depth greater than 5mm.
  • No possible restorability
  • Procedural errors
  • Previous Root canal treatment
  • Open apex

Single blinded