Sohair E. Ata Allah, Ibrahim H. Elkalla, Abeer M. Abd Elatif And Rizk A. El-Agamy,

ABSTRACT
Background: Since The Major Goal Of Endodontic Treatment Is To Decrease The Bacterial Load In The Root Canal System,. So The Lesion Sterilization And Tissue Repair Therapy Were Developed (L.S.T.R.) That Can Disinfect And Repair Damaged Tissue.

Purpose: To Compare Conventional Root Canal Preparationand L. S.T.R. Techniques In Endodontic Treatment Of Primary Molars. Methods: 45 Children, With Age Ranging From 3-9 Years-old Were Selected From The Clinic Of Pediatric Dentistry, Faculty Of Dentistry, Mansoura University. The Selected Children Were Classified Randomly Into Three Equal Groups According To The Material Used And Root Canal Preparation. Group I (control) Treated With Conventional Root Canal Preparation And Calcium Hydroxide -iodoform Paste, While Groups II And III (experimental Groups) Treated With 3-Mix Paste, And Calcium Hydroxide - Iodoform Paste Respectively, But Without Root Canal Preparation.

Results: At 3 Months Follow Up, There Was A Marked Improvement Of The Clinical Signs And Symptoms Including Pain To Percussion, Mobility, And Abscess Formation. No Significant Difference Was Found Between The Three Studied Groups Clinically. Radiographically After 3 Months Decreased Size Of Radiolucency In (2 Cases GI, I Case GII). Their Was A Significant Difference Between GI,GII, GIII,(P=0.12). At 6 And 9 Months, No Significant Difference Was Found Clinically Or Radigraphically. CLINICAL SIGNIFICANCE: From The Result Of This Study It Was Concluded That, LSTR Using 3- Mix Showed High Success Rate Clinically And Radiographically In Treatment Of Primary Teeth. LSTR Can Be Used As Alternative Treatment To Pulpectomy Especially In Uncooperative Children As It Is Simple And Takes Short Chair Side Time.