Bacterial penetration into filled root canals exposed to different pressures and to the oral environment—in vivo analysis

• Published in: Clinical oral investigations Vol. 22; no. 3; pp. 1157 - 1165
• Main Authors: Alves, Ana Maria Hecke, Pozzobon, Maria Helena, Bortoluzzi, Eduardo Antunes, da Silveira Teixeira, Cleonice, Souza, Beatriz Dulcinéia Mendes, da Fonseca Roberti Garcia, Lucas, Felippe, Wilson Tadeu
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-04-2018; Springer Nature B.V
• Subjects: Bacteria; Dentistry; Dentists; Disinfection; Endodontics; Inflammation; Medicine; Original Article; Pressure; Root canals; Statistical analysis; Teeth; Bacterial penetration; Periapical inflammation; Endodontics; Sealing methodology
• ISSN: 1432-6981; 1436-3771
• DOI: 10.1007/s00784-017-2199-7

Objectives
The study aims to correlate the depth of bacterial penetration into filled root canals with the time of exposure to the oral environment and different pressures.
Materials and methods
One-hundred and twenty-two root canals of male Beagle dog teeth were prepared and filled. The root canals were distributed into three groups, according to the pressure applied: (A) no pressure, (B) 30 kPa, and (C) 60 kPa. Then, the root canals were exposed to the oral environment, establishing sub-groups considering the time intervals of exposure: (1) 45 days and (2) 120 days (
n
 = 17). Sub-groups had positive and negative controls (
n
 = 5). The animals were sacrificed, and the specimens were prepared for histological analysis.
Results
There was no significant difference in the bacterial penetration among groups A, B, and C at 45 days (
P
 = 0.903) and 120 days (
P
 = 0.211). No statistically significant difference was found (
P
 = 0.608) between the exposure time intervals. Most of the specimens from experimental groups exposed for 120 days presented moderate inflammatory infiltrate.
Conclusions
Pressures of 30 and 60 kPa did not affect sealing ability of root canal filling. The time of exposure did not influence bacterial penetration, which was limited to the first 4 mm of the root canals exposed for 120 days.
Clinical relevance
This animal study demonstrated that disinfection of the first millimeters of root canals could be considered before retreatment of their entire length. However, clinical studies in humans should be conducted before validation of this protocol.