الفهرس 
Microbiology of necrotic primary teethOnly 14 pages are availabe for public view
Abstract
The treatment of pulp necrosis, particularly in primary teeth, is very complex making the access to the root canal difficult and is based on the elimination of the root canal infection through a good mechanical preparation and profound irrigation. Microorganisms found in the root canals of primary teeth are similar to those in the root canals of permanent teeth. Bacterial species such as E. faecalis has been reported in high prevalence in primary endodontic infections affecting children.
The aim of the current in vivo randomized controlled trial was to assess the antibacterial effect, as well as clinical and radiographical success of Chitosan, Chitosan nanoparticles, and Chlorhexidine gluconate gels as intra canal medicaments in necrotic primary molars.
The current study was approved by the ethical committee of Faculty of Dentistry Ain Shams University. A total of 45 necrotic mandibular primary molars in 42 patients aging 4-7 years old were randomly divided among 3 groups as follws:
group I (CS): 15 necrotic mandibular primary molars which were treated with a specially prepared gel containing 0.5% chitosan as an intracanal medicament for one week.
group II (CNPs): 15 necrotic mandibular primary molars which were treated with a specially prepared gel containing 0.5% chitosan nanoparticles as an intracanal medicament for one week.
group III (CHX); control: 15 necrotic mandibular primary molars which were treated with a specially prepared gel containing 1% chlorhexidine gluconate as an intracanal medicament for one week.
Teeth were isolated with a rubber dam. All carious tooth structure was removed and access cavity was created. The root canals lengths were measured from the pre-operative periapical radiographs. The first microbiological samples were collected with the help of 3 sterile absorbent paper points that was introduced into the distal root canal and was left for approximately one minute. Thereafter, the paper points were removed from the canals and transferred to a BHI transport medium and was sent to the laboratory for microbiological analysis and culture.
The canals were dried by using paper points and one of the experimental intracanal medicaments (Chitosan gel or Chitosan nanoparticles gel or1%CHX Gluconate gel) was placed in all root canals according to the test group. The teeth were then restored temporarily with reinforced Zinc oxide eugenol.
Patients were recalled after one week. The canals were irrigated with normal saline to remove the intracanal medicaments. The second microbiological samples were collected again with the help of absorbent paper points as described previously.
The canals were dried and filled with a resorbable paste of Zinc oxide eugenol. The pulp chamber was filled with a fast setting reinforced Zinc oxide eugenol, and molars were restored permanently with a stainless steel crown. After that, patients were recalled after 3 and 6 months for clinical and radiographic evaluations.
The results of the current study revealed an insignificant increase in total bacterial counts following treatment with CS. While both CNPs and CHX groups showed a significant reduction in total bacterial counts after one week compared to their pretreatment mean counts.
Regarding the effect of each medicament on E. faecalis after treatment, CS showed an insignificant reduction in the number of teeth that were positive for E.faecalis after treatment. While both CHX and CNPs groups, showed a significant reduction in the number of teeth that were positive for E.faecalis.
Results of CS and CNPs showed insignificant reduction in the number of teeth with S.aureus after treatment, while CHX showed significant reduction in the number of teeth with S.aureus after treatment. Table (8), fig(22)
However, odds ratio calculation revealed that CS had a greater antibacterial effect against S.aurues than E.fecalis, where CS was found to have the potential to reduce the number of teeth with E.fecalis and S.aurues after treatment by 25% and 59%, respectively.
Odds ratio calculation showed that CNPs have a greater potential to decrease the number of teeth with E.fecalis after treatment more than teeth with S.aurues.
While odds ratio calculation for CHX it has showed that a greater potential to decrease the number of teeth with both E.fecalis and S.aurues after treatment more than CS and CNPs.
Regarding follow up assessments, the highest clinical and radiographic failure rates were found to be in molars treated using 0.5 % chitosan gel. At 6 months, the most commonly encountered clinical failures were pain on percussion, incomplete resolution of gingival abscess, and minimal bone formation at radiographic follow up in comparison to other groups. At the last recall, one of the fifteen molars treated using 0.5 % chitosan gel was extracted due to persistent gingival abscess. While both CNPs and CHX groups showed high clinical and radiographic success rates that could also be attributed to their eater antibacterial effect than that of CS