L20 Dentoalveolar abscess

Question 1

Where is streptococcus salivarius found?

Answer 1

In the saliva and on the tongue

Question 2

What bacteria are found subginigvally?

Answer 2

Strictly anaerobic bacteria
- S. sanguinis
- Lactobacillus species
- Actinomyces species
- Fusobacterium species
- Treponema species
- Veillonella species
- Capnocytophaga
- Prevotella
- A.a
- P.gingivalis

Question 3

What type of bacteria cause periapical abscesses?

Answer 3

Subgingival bacteria
Strict anaerobes
Gram negative

Question 4

How does dental caries progress to a dentoalveolar abscess?

Answer 4

• Necrotic tooth can either progress to dentoalveolar abscess straight away or a periapical granuloma which can last weeks, years etc before becoming an abscess
• Chronic inflammatory processes at the root apex cause bone resorption

Question 5

What is Ludwig’s angina?

Answer 5

Where a dental infection spreads into the pharyngeal tissue planes (neck), obstructs the airway and can lead to death.

Question 6

What is cavernous sinus thrombosis?

Answer 6

Where infection from the maxilla spreads backwards into the sinus.

Question 7

What are alternative names for dentoalveolar abscesses?

Answer 7

• Periapical abscess
• Acute periapical periodontitis

Question 8

What dictates the spread of infection?

Answer 8

• Anatomical structures e.g. muscle attachments
• Infection perforates alveolar bone below attachment of buccinator = extra oral swelling
• Infection perforates bone above the attachement of buccinator = intra oral swelling

Question 9

What are the clinical and radiological features of a dentoalveolar abscess?

Answer 9

• Constant throbbing pain
• Often localised to a single tooth
• TTP
• Negative to sensibility testing
• Intraoral and/or extraoral swelling
• Radiograph will show a periapical radiolucency

Question 10

How should a microbiological sample be taken?

Answer 10

Needle aspiration to reduce contamination from saliva and protect the strict anaerobes present.
- Will see a mixed bacterial species
- The gram negative bacteria are those causing the abscess
- Strict anaerobes
- PMNs present

Question 11

Name the facultative and strib anaerobes found in dental abscesses.

Answer 11

Question 12

What are the 2 forms of antimicrobial suscpetibility testing?

Answer 12

• Incubated agar plate with a disc of antimicrobial, check for zone of inhibtion
• E-Test: incubated agar plate with a strip of antimicrobial of varying concentrations, can get a value of the MIC - minimum inhibitory concentration for that specific bacterial species

Question 13

What species is most commonly resistant to penicillin, why is this?

Answer 13

Prevotella species
Produce beta lactamase

Question 14

How can drainage be established?

Answer 14

• Incision of soft tissues (drain placed for continued drainage)
• Extraction of tooth
• Pulp extirpation

Question 15

When should you consider antibiotics for a dentoalveolar abscess?

Answer 15

• Infection is spreading
• Drainage not achieved
• Patient is systemically unwell
• Patient is immunocompromised

Question 16

What are the 3 first line abx?

Answer 16

• Amoxicillin 500mg capsules TDS for 5 days (double dose for severe infection)
• Phenoxymethylpenicillin 500mg (250mg tablet x2) QDS for 5 days (double dose for severe infection)
• Metronidazole 400mg tablets TDS for 5 days (interacts with alcohol and warfarin)

Question 17

What is the mechanism of penicillin action?

Answer 17

Binds to transpeptidase active site on cell wall of bacteria. Causes cell wall to break down = bacterial lysis.

Question 18

What are the 3 second line abx?

Answer 18

• Clindamycin 150mg QDS for 5 days (risk of abx associated colitis) capsules
• Co-amoxiclav 250/125mg TDS for 5 days (risk of cholestatic jaundice) clavulanic acid inhibits beta lactamase, tablets
• Clarithromycin 250mg BD for 7 days (not for statins, warfarin, preg, breast feeding, caution with hepatic or renal impairment or prolonged QT interval) tablets

Question 19

What prescribing considerations should be made?

Answer 19

• Previous hypersensitivity reactions
• Drug interactions
• Pregnancy or breastfeeding
• Medical conditions e.g. hepatic or renal impairment

Question 20

What is a chronic discharing sinus?

Answer 20

Untreated abscess = chronic infection tract extraorally

Question 21

Describe pericoronitis.

Answer 21

• Operculum overlying partially erupted tooth
• Ecological niche for anaerobic bacteria to proliferate under the operculum
• Irrigation
• Abx if there is swelling or systemic involvement
• Metronidazole
• May require XLA of ipsilateral maxillary third molar, on occlusion the upper third molar may cause trauma to the operculum so can be removed

Question 22

Describe suppurative sialadentitis.

Answer 22

• Acute bacterial infection of a salivary gland
• Usually the parotid or submandibular gland
• Painful swelling and purulent discharge
• Amoxicillin if pt systemically unwell

Question 23

How is peri-implantitis managed?

Answer 23

A destructive inflammatory proves affecting the soft and hard tissues surrounding a dental implant.
Microbiology is similar to that of periodontal disease.
Treatment = debridement, not abx