One of the major concerns in pediatric dentistry is premature loss of necrotic primary teeth which may cause a deleterious effect on the growth of the facial skeletal complex. In order to sustain the primary tooth as a natural space maintainer, pulpectomy is considered the treatment of choice.

The essential part of endodontic treatment is to shape and clean the root canal effectively from infected tissue with microbial reduction, whilst maintaining the original configuration without creating any procedural errors . Even though, manual instrumentation as used for that purpose in deciduous teeth, presents some limitation concerning root canal cleaning, anatomical fidelity and chair-side time.

To achieve successful pulpectomy technique for the primary dentition in a fast and simple procedure, with short chair time as well as effective debridement of the root canals, rotary instrumentation is one of the methods recommended over the manual.

1. Trial design:

   Randomized clinical trial, parallel groups design with 1:1 allocation ratio.

2. Method:

   Interventions

   A. Diagnostic procedure:

   • Clinical examination will be done on the dental clinic using mirror and probe to assess the eligibility.
   • Diagnosis of the cases will be performed according to guidelines of AAPD 2017 for treatment of vital pulp therapy in primary teeth.
   • An individual XCP (Extension Cone Paralleling) index will be prepared for each patient by registering the bite to allow consistent comparisons of the radiographs.
   • Preoperative periapical radiograph and photographs will be taken a baseline record.

   B. Intra operative procedure:

   • Local anesthesia administration using articaine 4% with epinephrine 1:100000.

   • Rubber dam application and access cavity preparation will be established using a sterile bur.

   • Coronal pulp tissue will be removed using sharp large spoon excavator.

   • Working length will be determined using no 15 hand K-file that will be kept 2mm short of radiographic apex.

   • Then, the root canal preparation will be done

     • In control group, hand instrumentation will be carried out using hand K-file up to no. 30 K-file using quarter turn and pull motion.
     • In intervention group, rotary instrumentation will be preceded by initial hand instrumentation using no. 15 K-file to check the patency. Then, the rotary instrumentation will be done using the Kedo-S rotary files for primary teeth with D1 and E1.

   • Using EDTA gel as a lubricating paste during canal preparation with rotary files.

   • Saline irrigation for removal of debris after each file.

   • Dryness will be done using paper points size 35 and 40.

   • Root canals will be obturated using calcium hydroxide iodoform paste (Metapex). The Metapex syringe willbe inserted into the root canal space, near the apex. The paste will be pressed down into the canals and the syringe will be slowly withdrawn.

   • The access cavity will be sealed using GC Fuji IX capsule.

   • The immediate postoperative radiograph will be done to reveal optimal filling with metapex.

   • After that, stainless steel crowns will be cemented by Ketac Cem.

   C. Follow up:

   Clinical and radiographic evaluation will be performed at 1week, 3, 6, 9 and 12 months.

   D. Criteria for discontinuing or modifying intervention:

   In case of unsuccessful outcomes of the intervention technique, the case will be managed .

3. Recruitment:

   Recruitment of the patients will be from the outpatient clinic of Pediatric Dentistry and Dental Public Health Department, Cairo University. Screening of patients will continue until the target population is achieved.

4. Implementation Co-supervisor; Fatma Korany will assign which participant tooth will be included to either control or intervention groups according to the generated random sequence.

5. Masking/blinding:

The radiographic outcomes assessor will be blinded in this study. 8- Data collection, management, and analysis: 9- Data collection methods

Baseline data will be collected by the operator through a paper-based Case Report custom made form (CRF) which will be developed by the research team. It will include the following items:

1. Patient serial number.

2. Demographic data.

3. Patients medical history:

   • Past medical history.
   • Any present disease or illness.
   • Current medication.
   • Any specific pre-treatment medication.

4. Past dental history.

5. Records for current dental condition (intra-oral examination and caries index). The custom made CRF will be developed before online registration of the study protocol. CRF will be anonymous where patients will be identified by their serial number. The full detailed personal data of the patient will be written in a separate sheet having the patient's serial number for further contact with patient, this sheet can be only seen by the operator and the supervisors. The Co-supervisor; Dr.Fatma Korany, will have the role to monitor the process of data collection and check if there is any incomplete CRF.

Inclusion Criteria:

• Primary posterior teeth requiring pulpectomy.
• Cooperative patient in age range from 4 to 6 years
• Absence of internal or external pathologic root resorption.
• Presence of adequate coronal tooth structure.
• Two-thirds of each root remaining.
• Parent or guardian agree for participant in the study

Exclusion Criteria:

• Excessive mobility.
• Children lacking cooperative ability.
• Children with underlying systemic disease.
• Children with special health care needs.

after thesis defense. the study will be published internationally to be available for everyone

study will be available within 2 year.

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