Establishment of an in-vitro root canal-apical complex model / 重庆医学

ABSTRACT

Objective To establish an in-vitro root canal-apical complex model for studying the mechanisms of the infected root canal to apical periodontitis and periapical biofilm .Methods Single rooted premolar extracted for orthodontic ,was sealed in sterile vial containing LB solid medium ,and the culture medium covered apical thirds .Totally 25 root canal-apical complex models were prepared .Five models were randomly selected for the bacteria detection in periapical by PCR at 1st day .The remained 20 models were randomly subjected to a control group(n=10) and experimental group(n=10) .Extracted teeth were opened in experimental group and control group with no treatment .All models were exposed in air .At 21st day ,bacteria were detected through PCR in root canal and apical;endotoxin content in apical was assayed by chromogenic end-point limulus test .Results In apical ,bacteria was not found in all groups ,but not for the experimental group .The mean endotoxin content was (8 .913 ± 0 .614)EU/mL in control group and (10 .525 ± 0 .981)EU/mL in experimental group .The endotoxin content was increased significantly in experimental group ,when compared with control group(P<0 .01) .Conclusion Root canal-apical complex was established in vitro through this method .Bac-teria was not easy to reach the apical when the infected root canal was not disturbed .Bacteria in the infected root canal caused apical periodontitis through the secretion of virulence factors such as endotoxin .