The study will be two parallel group, triple blinded randomized controlled clinical trial that based on CONSORT (consolidated standards of reporting trials) guideline .The selected participants according to inclusion and exclusion criteria will be randomly allocated in two groups using (Research Randomizer Program) .

Blinding All participants don't know the type of received restorative material (ACTIVA Kids or High -viscosity GI restorative material) and the outcome will be evaluated by a examiner other than operator who doesn't know the type of received restorative material also.

Study setting The study will be performed at pediatric Department and Dental Public Health Department of Faculty of Dentistry, Ain Shams University, and at the institute of Graduate Studies and Research, Ain Shams University.

Sample size: 60 participants Recruitment/Setting The all participants of this study have been selected after complete clinical examination has been done with full medical and dental history , history of medications and history of hospitalization. In patients who receive dental treatment as an usual care in clinics of Pediatric Dentistry and Dental Public Health Department at faculty of dentistry, Ain-Shams University.

Informed consent designed to include all data about dental procedures in this study and clear more details about time consuming in the procedure and follow up visits, used materials and adverse event of this procedure . All participants have the wright to withdraw from this study at any time .The consent will be assigned from each patient by the patient's parents or guardians after explanation of the study.

The full mouth rehabilitation will be performed by postgraduate student registered at the master Degree at the Pediatric Dentistry and Dental Public Health Department Faculty of Dentistry, Ain- Shams University All subjects receive instructions on oral health, particularly in relation to oral hygiene and sugar consumption

Inclusion Criteria:

1. Children aged from 4 to 8 years old, in good general health
2. Children classified as class 3 or 4 based on Frankel et al. classification. (26)
3. The children have at least one primary molar with class I carious lesion.
4. Asymptomatic teeth (without spontaneous pain)

Exclusion Criteria:

1. Medically compromised patient
2. Presence of pulp exposure, pain, mobility
3. Presence of swelling, abscess or fistula near the tooth
4. Not accessible carious lesion to hand instruments

carious primary molars limited to occlusal table (class I cavity) in 4-8 yrs old patients

3 months, 6 months,1 year

failure of restorations in participated primary molars. (non-serious adverse event)