The aim of this study is to evaluate the quality of obturation and the time efficiency of rotary versus manual instrumentation in roots of deciduous molars clinically where the:

• Primary objective Is to evaluate the time efficiency
• Secondary objective Is to evaluate the quality of obturation Clinical and radiographical follow up will be performed for 18 months to investigate the clinical and the radiographic success for the Conventional and Rotary groups.

The study will be conducted in two parts as follows:

In-vitro part as a training part to practice, test the speed of the rotary system, followed by application clinically.

Obturation will be done using two different filling techniques:

• Incremental filling Technique
• Disposable syringe Technique.

Then the instrumentation time and the quality of obturation will be recorded.

The study will be conducted by recruiting patients from the Outpatient clinic of The Pediatric Dentistry and Dental Public Health department, Faculty of Dentistry, Ain Shams University:

Inclusion Criteria:

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Children included in the study should conform to the following criteria:

1. Patients between ages 4-7 years old with at least one mandibular vital or non-vital primary molar indicated for pulpectomy will be selected.
2. Absence of periapical or interadicular radiolucencies, inflammatory root resorption, sinus tract or gingival abscess.
3. No physiological root resorption.
4. The teeth should have enough coronal structure for full coverage Stainless-Steel crowns.

Exclusion Criteria:

• 1. Children who are extremely uncooperative and difficult to manage 2. Children suffering from any physically or mentally disability that will complicate the treatment: Special Health Care needs (SHCN) 3. Teeth of poor prognosis due to presence of an abscess or a sinus, mobility, advanced bone or root resorption or Non-Restorable teeth.