This is a clinical trial that aims to compare the success rate, child and parent acceptance of conventional Hall crown technique (CHT) to modified Hall crown technique (MHT)in treating carious primary molars. Eligible children will receive CHT on one side and MHT on the other side. The time interval between both visits will be 1-2 weeks.Patients demographics and pain history will be recorded and pre-operative radiographs will be taken. An observer will assess and record the child's pain perception during each treatment visit. Time taken for each procedure will be recorded by the research assistant each visit prospectively from the moment the child sits on the dental chair till the end of procedure. Parental preference and child acceptance for each procedure will be recorded after treatment is finished using parent and child questionnaire. Clinical follow up will be conducted at 3,6 and 12 months to assess and compare the success rates of both techniques. Radiographs will be taken at 12 months to evaluate and compare radiographic success.

This is a split mouth randomized clinical trial that aims to compare the success rate, child and parent acceptance of conventional Hall crown technique (CHT) to modified Hall crown technique (MHT)in treating carious primary molars. Eligible children will receive CHT on one side and MHT on the other side. The time interval between both visits will be 1-2 weeks.Patients demographics and pain history will be recorded and pre-operative bitewings will be taken. An observer (research assistant who will be trained, calibrated, and blinded to the treatment used) will assess and record the child's pain perception during treatment visit. Time taken for each procedure will be recorded by the research assistant each visit prospectively from the moment the child sits on the dental chair till the end of procedure. Parental preference and child acceptance for each procedure will be recorded after treatment is finished using parent and child questionnaire. Clinical follow up will be conducted at 3,6 and 12 months to assess and compare the success rates of both techniques.Bitewings will be taken at 12 months to assess for crown fit and radiographic pathology.

Inclusion Criteria:

• Fit and healthy (ASA 1) children.
• 4-9 years old children.
• Bilateral ICDAS (1, 2, 3 or 4) class I or II carious lesions on primary molars matched for tooth type.
• Teeth with vital pulp with no signs or symptoms of irreversible pulpitis, necrosis, or an abscess.
• No tenderness to percussion, or pathological mobility.
• Prior bitewings must be available showing no radiographic evidence of interradicular radiolucency or caries reaching pulp.
• Contact point is closed.
• Patient has good level of cooperation for the intended procedure.
• Parents consented for their children to be included in the study.

Exclusion Criteria:

• Child with systemic illness (ASA 2,3,4).
• Unmatched carious lesions on primary molars.
• Teeth with deep caries (ICDAS score5 or 6) requiring pulp therapy.
• Irreversible pulpitis or pulp necrosis.
• Pathological mobility.
• Prior bitewings are unavailable.
• Contact point is open.
• Patient has poor level of cooperation for the intended procedure.