Microbiomes of Endodontic-Periodontal Lesions before and after Chemomechanical Preparation

By Gomes B, Berber V, Kokaras A, Chen T, Paster B

Date: 10/2011
Journal: JOE

Purpose: to compare the microbial profiles of endodontic-periodontal lesions before and after chemo-mechanical preparation (CMP) using Next Generation Sequencing (NGS) and culture techniques. 

N= 15 teeth


•Endo-Perio lesions defined as having PP > 6 mm, necrosis, PARL.

•PA and BW taken at baseline visit along with PD, BOP, CAL, PI.

•All measurements were performed using a periodontal probe at 6 sites per tooth and were recorded

Periodontal plaque sample collected from deepest probing depth of each tooth with paper points before RCT then again at the end of visit after RD removed.

Endodontic sample (1st) collected from root canals with paper point •Teeth isolated, crowns disinfected with 30% HP and 2.5% NaOCl

•2-stage access was made under saline irrigation (no water)

•Before entering pulp chamber access was disinfected, and new sterile bur used to access

•A single canal sample was taken in multirooted teeth from canal with deepest PP

•Canals C&S with irrigation between files with 2% CHX and inactivated •Final rinse with EDTA 17% after complete C&S  for 3 minutes then 5 mL saline

2nd Endodontic sample collected, Obturation completed if canals dry and asymptomatic; otherwise CaOH applied.


•Microbial DNA from Endo/Perio samples extracted and purified

•DNA quantified

•2 separate PCR reactions performed to amplify the 16S rRNA due to small amount of DNA in samples

•Over 50,000 sequences of 441 bp each were obtained, bad reads and chimeric sequences were removed from analyses.

•Endodontic sample cultured in anaerobic chamber

•Cultures characterized based on morphologic type, and according to gaseous requirements, Gram stain, and catalase production

•Associations between clinical parameters and microbial profiles were determined

Most highlighted Results:  

1.+50% of the sample were molars

2.Obligate anaerobes and rods predominated in the RCs investigated. 3.The number of gram-positive and gram-negative taxa detected in the RC was very similar before and after treatment, with a slight predominance of gram-negatives after CMP.

4.After C&S significant decrease in bacterial count was noted