Aim of the present study is to assess the in vivo susceptibility of root canal bacteria to Chitosan,Chitosan nanoparticles ,and Chlorhexidine gluconate when used as intra canal medicaments in necrotic primary molars

Primary teeth with necrotic pulp are a common problem in pediatric dentistry especially in very young children before first permanent molar eruption. Early loss of primary teeth can cause a number of problems, including space loss, esthetic, phonetic or functional problems. However, some of the infected primary teeth can remain functional until the exfoliation via endodontic treatment. Pulpectomy is indicated in primary teeth with necrotic pulp in which the radicular tissue exhibits clinical signs of chronic inflammation.

The primary objective of pulp therapy is to maintain the integrity and health of the teeth and their supporting tissues. One of the most important aims of pulpectomy treatment is to eradicate or substantially reduce the microbial load in the root canal system. Currently, insignificant data is available regarding the identification of microbiota in deciduous teeth with pulp necrosis and periapical pathosis. However, documentation exists in relation to the polymicrobial nature of microbes predominated by anaerobes in the root canals of deciduous teeth with necrotic pulp and periapical lesions similar to permanent teeth.

Various microorganisms isolated from infected root canals include Streptococci, Staphylo-coccus, Diptheroids, Peptostreptococcus, Lactoba-cilli, Propionibacterium, Actinomyces, Bacteroides, Fusobacterium etc.

The commonly isolated facultative anaerobes microorganisms from primary root canals, Enterococcus faecalis was isolated in 30% of cases, Escherichia coli in 28.4%, Staphylococcus aureus in 25%, α-hemolytic Streptococci in 15% and Proteus mirabilis in 1.6% of cases.

E. faecalis is a persistent organism that plays a major role in the etiology of persistent periradicular lesions after root canal treatment. It is commonly found in high percentage of root canal failures and is able to survive in the root canal as a single organism or as a major component of the flora.

Therefore, intracanal medication was advocated to further reduce bacteria in the root canal system and reduce the failure of root canal treatment. Thus, chemomechanical debridement using intracanal medicament and irrigants is essential to eliminate these microorganisms, and their by-products that remained in the pulpal space which was inaccessible to systemic antibiotics and root canal instrumentations.

Chlorhexidine (CHX) usually used as a root canal irrigant especially in primary molars owing to its biocompatibility, substantivity and wide antimicrobial activity.

Recently there is an increase interest in using natural product in medical fields. Chitosan is a natural and non-toxic polysaccharide with many biological applications, particularly as an antimicrobial agent. Chitosan nanoparticle is a bioactive and environment friendly material with unique physicochemical properties .

To date, none of the studies has consistently investigated the effects of Chitosan as new alternative when used as root canal medicament in primary teeth. Therefore the present study aimed to compare in vivo susceptibility of root canal bacteria to chitosan, chitosan nanoparticals, and chlorhexidine gluconate as intra canal medicaments in necrotic primary molars.

Inclusion Criteria:

• Apparently healthy children.
• Age 4-7 years
• Children should have at least one non vital and restorable mandibular molar .
• Cooperative children.
• Children that did not take any antibiotic for at least one month before sample collection

Exclusion Criteria:

• Medically compromised children.
• Children under antibiotic therapy.
• Non restorable molars.
• Root resorption more then half of the root length.