• Preservation of the primary teeth is a mandatory issue for maintaining the integrity of the normal dentition and functioning till the eruption of the successors.
• furcal perforations may occur due to iatrogenic and non-iatrogenic causes.
• Despite the high successful outcomes in perforation repair with MTA, there are some issues which prevent the clinicians from using it for many cases such as its very long setting time and its difficult manipulation.
• Biodentin could be used as an alternative to MTA in reparative treatment procedures due to its ability to provide a hermetic seal and durable restoration and thus an optimal sealing is expected.
• The importance of the trial lies in testing the sealing ability of Biodentine using scanning electron microscope. Biodentine has short setting time and is easier in manipulation than MTA which are major needs when dealing with pediatric patients to be able to give best results in short time.

• By immediate diagnosis and sealing of furcal perforations in primary molar teeth with a biocompatible material, the prognosis is usually favorable.
• MTA has high clinical efficacy, but there were some drawbacks which made it difficult for the clinicians to use it in many cases. The major ones being very long setting time and difficult manipulation.
• Biodentine has a good sealing ability, high compressive strengths, short setting time, biocompatibility, bioactivity and biomineralization properties that make it available to be used in endodontic repair procedures.
• 42 extracted primary molar teeth will be collected, sterilized and stored according to the Occupational Safety and Health Administration guidelines and regulations.
• A standard access cavity will be prepared in each tooth using a diamond bur and non-end cutting bur in high-speed handpiece with water spray. A 0.5 mm round bur will be used to standardize the size of furcal perforation, and the furcal involvement will be made on the center of the pulpal floor.
• After the furcal perforation, the blocks will randomly be divided into two groups
• Control group: MTA Group, Using amalgam applicator the material will be carried and sealed in the furcation site.
• Intervention group: Biodentin Group,The material will be scooped and applied on the perforation site.
• Outcome : sealing ability measurement method : scanning electron microscope unit of measurement : µm

Inclusion Criteria:

• Freshly extracted discarded primary molars
• Primary molars with intact furcation ( no caries, no perforation, no resorption )
• Physiologic root resorption not more than two-third of root length

Exclusion Criteria:

• Exfoliated primary molars
• Primary molars with internal resorption
• Primary molars with extensive tooth decay of the crown
• Primary molars with discoloration
• Cracked tooth