Success of root canal treatment is largely dependent on the elimination of harmful
microorganisms and primarily bacteria from the root canal system through chemomechanical
preparation and using intracanal medication in order to cure or prevent periapical
disease and allowing the maintenance of the dental element.
Failure of endodontically treated teeth is multifactorial; it is believed that the most
important reason for endodontic treatment failure is the presence of microorganisms in
the apical third of the root canal that survive after endodontic procedures.
Enterococcus faecalis (E. faecalis) is among the most commonly isolated bacteria from the
failed endodontically treated root canals. Enterococcus is a facultative anaerobic
gram-positive coccus that invades dentinal tubules, can survive in alkaline environment,
endure prolonged periods of starvation, and have certain virulence factors and lytic
enzymes. Its prevalence in primary endodontic infection ranges from 4% to 40 % and
secondary endodontic infection ranges from 24% to 77%.
Moreover, anatomical complexity and diversity of root canals that hinders a complete
disinfection of root canal space by chemo-mechanical instrumentation alone. So, the use
of an intracanal medication remains an important adjunct to complete elimination of
remaining bacteria by reaching areas that instruments and irrigation could not reach in
addition to long-standing infections.
So, using of intracanal medication is mandatory in infected endodontic cases as more
thorough debridement is achieved because of the longer overall time used for the
treatment.It prevents regrowth of the remaining microbiota within the root canal system
and also to increase the level of disinfection.
Chlorohexidine (CHX) is an intracanal medication that has an antibacterial effect plus
high substantivity which leads to a prolonged action; however it isn't able to eradicate
bacteria completely from root canals.
Triple antibiotic paste (TAP) is a combination of metronidazole, ciprofloxacin, and
minocycline. This combination is able to remove diverse groups of obligate and
facultative gram-positive and gram-negative bacteria, providing an environment for
healing. So, this allows disinfection, and possible sterilization of the root canal
system.
Introduction of nanotechnology in dentistry has been developed by using nanoparticles
(NPs) exclusive features that include smaller sizes and increased surface area to volume
ratio. They have higher chemical reactivity and charge density leading to greater
interaction with the environment and negatively charged bacterial cells, compared to
their bulk counterparts. These advantages may be used to design highly anti-microbial
agents with maximal therapeutic efficacy and minimal side effects.
Intracanal medications in the nano-form can achieve optimal therapeutic activity through
their interaction with microorganisms at both the sub-cellular and molecular levels.
Because of their small size, they can penetrate well into the complex anatomy of the root
canal system.
Chlorohexidine and triple antibiotic paste cannot be converted into nanosized forms, they
can be loaded with other nanosized materials like silver and chitosan nanoparticles to
gain the benefit of both materials and become nanoparticulate.
The triple antibiotic was utilized together with chitosan as a vehicle to increase its
stability and controlled release of the medicament. Triple antibiotic-loaded chitosan
nanoparticles (tachnp) paved the way for the use of chitosan which has an excellent
antiviral, antifungal and antibacterial properties.
On the other hand, Chlorohexidine loaded by silver nanoparticles (Ag-np) had high
antimicrobial efficacy which is due to the dual antibacterial effect of Ag-np and
chlorohexidine, it also allowed the use of silver nanoparticles which are known for their
ability to destabilize the bacterial cell membrane and increase its permeability which
leads to bacterial death.
According to the current knowledge, there is limited information concerning the efficacy
of different new combinations of intracanal medications on bacterial count reduction of
retreatment cases. Therefore, the purpose of the present study is to evaluate the
antimicrobial effect of nano-based intracanal medications on Enterococcus Faecalis in
secondary endodontic infection cases.