WHY ENDO FAIL Flashcards
The goal of endodontic treatment
is to eliminate or significantly reduce the bacteria within the root canal system, and to prevent recontamination of the root canal filling/prevent the development of apical periodontitis.
The aim of endodontic treatment
is to disinfect in the root canal system and prevent or heal apical periodontitis.
most imp prognostic factor in successful endo?
Complete eradiation or reduction in microbial burden in the root canal system is a crucial prognostic factor in determining the successful outcome of endodontic treatment.
is it possible for complete eradication of m/o?
Despite meticulous cleaning and shaping, not every surface of the root canal system is touched by the mechanical instrumentation. The complex morphology of the root canal system presents space in the dentinal tubules, apical ramifications, isthmuss and recesses where bacteria are able to evade the noxious antiseptics and medicaments used in endodontic treatment.
why does endo fail?
Endodontic treatment might still fail in some cases despite thorough cleaning and shaping. This is most likely due to the presence of bacteria in the apical ramifications of the root canal system (Nair 2006 ). Failure of endodontic treatment is usually due to either persistent infection in the root canal system or reinfection of the root canal system.
Persistent infection: M/O must:
- Survive in a drastically changed environment, where nutrient is scarce to non, and bacteria must be able to survive in starvation
- Resist intracanal medicaments and irrigants used:
a. E. Faecalis able to withstand high ph of caoh. Hide in dentinal tubules, starvation, mono-infection. 22-77%
b. C. Albican able to withstand high ph caoh. Can grow in monoinfection, go through long periods of starvation
c. S. Cocci. 20%
d. Actinomyces - Virulence
a. Produce metabolites to mount periradicular inflammation
b. Able to utilise nutrients from serum transudate in apical foramen and accessory canals
c. Some are able to degrade collagens from dentinal tubules
To mount a AP: M/O must
- Adapt to this new harsh environment
- Able to source nutrients. Remaining tissues remnants are temporary, bacteria must be able to source fluids from the ramifications and apical foramens.
- Be able to multiply
- Reach number high enough to elicit tissue damage.
Microbiodata in untreated canals
- Polymicrobial infection
- Changing with stage and time of infection.
- Predominantly obligate anaerobes bacteria
- Equal amount of Gram +ve and Gram –ve bacteria
- 3 distinct phases:
a. Sacchorolytic m/o predominantly fermenting carbohydrates from the oral cavity.
b. Degrades protein into amino acid and peptide, some carbohydrate (F. Nucleatum, P. intermedia, Veillonella parvulla)
c. Utilised amino acid and peptide as main nutrient source (P. micros, Eubacteria, F. Nucleatum) - Associated with Periapical abscess
a. P. Micros
b. P. intermedia
c. P. endodontalis
D/Dx of PA lesion
- Intraradicular infection
- Extraradicular infection
- Cyst
- Cholesterol crystals
- Foreign body reaction
- Scar tissue
Intra-radicular infection
- m/o present
- cause
a. Main cause of persistent infection.
b. Bacteria in apical ramification of root canal system known to cause persistent infection.
c. Enterococci. Streptococci, candida albicans
Extra-radicular infection
- m/o present
- cause
Actinomyces Israeli , Proprionibacterium spp
- Populate extra-radicular via extrusion of infected dentinal chips, long standing abscess, sinus tract
Cholesterol crystals
- Locally dying inflammatory cells
- Erythrocyte from stagment blood cells
- Lipids from cholesterol.
- Inflammation mounted by (macrophage, neutrophils, plasma cells) release pro-inflammatory cytokines (IL-1Alpha) root resorption worsen PA lesion
Foreign body reaction
GP/plant material/cellulose/paper point.
scar tissue
Healing by CT.
Not a pathology
Oral micro-flora
- Diverse species
- > 500 species
- 10 to power of 10 bacteria in the oral cavity
- correlation exist between size of PA lesion and no of bacteria present
- consist of : bacteria, fungi, viruses and occasionally protozoa
- Polymicrobial microflora
endodontic disease and oral micro-flora
- Endodontic disease is caused by the pathogenic effect of bacteria and the host response.
- Dental pulp exposed to the oral cavity can become infected in the presence of opportunistic m/o.
- Only some selective m/o are able to survive and proliferate in the harsh environment of the root canal system and are able to cause a disease state at the periradicular tissues.
- Identification of these m/o are important for study of efficiency of root canal treatment and for future research into modalities to help improve treatment outcomes.
Test to assess/investigate m/o:
Sensitivity - parameter that can be used to determine the relative effectiveness of a diagnostic test
Specificity - the ability to identify organisms correctly.
DETECTION OF MICROORGANISMS:
- Microscopy
- Culturing
- Immunoessay
- Molecular methods
Factors affecting radiographic changes of lamina dura
- Direction of X-ray beam
- Shape and position of root in relation to X-ray Beam
- Occlusal forces
Factors affecting radiographic changes of AP:
- location of the lesions in different types of bone (Because there are more minerals per unit volume in cortical than cancellous bone, the resorption or demineralization process will manifest radiolucent changes)
- lesion may be visualized more readily when it is near, or in the cortex. It may not be or is less likely to become apparent in the cancellous bone.
(Hoomonan & Ostravik 2002)
Bender and Seltzer have reported that peri- apical lesions can be detected radiographically only when loss of alveolar bone is accompanied by cortical bone involvement.
Sensitivity of PA and OPG in detecting PA lesion by Estrella 2008
- Sensitivity of PA- 0.55
* Sensitivity of OPG- 0.27
Nutrient for microbes in the root canal system
• Derived from the oral cavity, degenerating connective tissue, dentinal tubule contents or serum-like fluid from periapical tissue.
• Permits growth of anaerobic bacteria capable of fermenting amino acids and peptides
• Coronal
- Dominated by Facultative anaerobic bacteria (streptococci) when root canal exposed to the oral cavity (for source of nutrient, carbohydrates)
• Apical 3rd
- Dominated by anaerobic bacteria
• Facultative anaerobic bacteria grow well in anaerobiosis, although prime energy source is carbohydrates.
Whats is a pathogen
Pathogen microbe capable of causing host damage, where the host damage can result from either direct microbial action of the host immune response.
what is an endodontic pathogen
Endodontic pathogen microorganism capable of inducing the tissue destruction of AP
