Aetiology, Pathology, Microbiology, Immunology of pulpal and periapical disease Flashcards
Through what routes might micro-orgs enter into the pulp/root canal and cause pulpal/peri-apical disease
- Dental caries
- Cracks
- Trauma
- Resorption
- Perio-related
- Microleakage
What is the pulp responsible for
- Sensory response
- Dentine tubule sclerosis
- Tertiary dentine (reparative and reactionary)
- Inflammatory response
When might micro-org penetration damage be reversible and how can these cases be treated
- Before they penetrate into pulp/deep into pulp
- Treatment by removing dental caries if present and place an effective and appropriate restoration
What can happen to the pulp if the damage is irreversible and how can these cases be treated
- The pulp can become inflamed, and areas of necrotic tissue and abscess formation
- Treatment either RCT or extraction
What can the inflammatory response of endodontic origin result in
Eventually can lead to pulp deaths and peri-radicular radiolucency
Describe the distribution of bacteria in the root canal
- More micro-organisms coronal
- Facultative anaerobes coronal
- Obligate anaerobes apical
- Micro-organisms are within the root canal and not in the peri-apical lesion
What is the function of the periapical lesion
It is an inflammatory lesion that is the first line of defence preventing micro-organisms invading periapical tissues
What non specific host defence reactions are elicited by bacteria and their by products in the pulp
- Acute inflammation
- Activation of the kinin and complement systems - release of histamine, plasmins, hangman factor, prostaglandins and leukotrienes
- Chronic inflammation is infection persists
What specific host defence reactions are elicited by bacteria and their by products in the pulp
- Cellular and humoral immunity involves T and B lymphocytes, lymphokines, plasma cells and immunoglobulins
- Type 1-4 reaction can be involved
What factors will lead to apical periodontitis
- Distribution of different cell populations in the lesion
- Presence of absence of epithelial cells
- Whether the lesion has transformed into a cyst or not
- Relationship of the cyst cavity to the root canal of the infected tooth
What can acute apical periodontitis develop into
A primary abscess, maybe from an acute exacerbation of a chronic apical periodontitis (secondary)
What are the characteristics of chronic apical periodontitis
Inflammation at the tooth of a long standing nature called a periapical granuloma:
Presence of:
- Granulomatous tissue
- Predominantly lymphocytes, plasma cells and macrophages
- Either epithelialise or non epithelialised
What is a periapical true cyst
A classification of apical periodontitis that is a distinct pathological cavity completely enclosed in an epithelial lining so that no communication to the root canal exists
What is a periapical pocket cyst
A classification of apical periodontitis that is an apical inflammatory cyst sac like epithelial-lined cavity that is open to and continuous with root canal (responds to root canal treatment)
Where in root canal are the majority of infections
Intraradicular
What are some common micro-orgs found in necrotic pulp tissue
- Peptostreptococcus
- Eubacterium
- Prevotella
- Fusobacterium
- Streptococcus
- ## Yeasts
What do most necrotic pulp cultures contain
- Obligate anaerobes
- Anaerobes, peptide and amino acid degrading bacteria
- Oral yeasts: candida albicans
What kinds of bacteria are commonly found in persistent/secondary endodontic infections and give examples
Many +ve gram and many coccoid facultative anaerobes:
- Streptococci
- Enterococci
- Lactobacillus
- Yeasts
- Peptosterptococcus
What seems to be the predominant species of bacteria in root filled teeth with unsuccessful outcomes
Enterococcus Faecalis
Yeasts are commonly asccoaited with persistent infections as well
When can extra-radicular infections be established
Apical periodontitis lesions are effective barriers to infection, if this barrier is overcome, an extra-radicular infection can be established
What makes the root canal an ideal environment for microbe growth
- Warm, moist
- Nutritious
- Anaerobic
- Largely protected from host defences
- Bacteria can communicate each other
- Bacteria can produce virulence factors that create tissue damage
What forms do bacteria survive in the pulpal/periapical tissue
- Planktonic state - free floating micro-orgs not attached to a surface (may be single cells or clumped together)
- Biofilms - community of bacteria or micro-organism and their extracellular polymer that is attached to a surface
Bacteria in what form are resistant to treatment
Biofilms in root canals -
- exopolysaccharide in which bacteria are embedded may resist diffusion of antibacterial agents
- different layers of bacterial cells may act as barrier to diffusion
- Some bacterial cells maybe dormant and more resistant to killing
- Cell may exhibit specific resistance mechanisms
