Microbes in Dental Disease

Question 1

What bacteria is indicated in caries?

Answer 1

Streptococcus Mutans

Question 2

What virulence factor does Strep mutans have?

Answer 2

Glycolytic systems

EPS/sucrose metabolism

Very acidic

Attachment mechanisms- GTF, Ag

Ecological competitiveness at low pH

Question 3

Describe caries progression in terms of biofilm formation.

Answer 3

Adhesion of bacteria
Survival and growth
Biofilm formation
Complex plaque
Acid
Caries

Question 4

What clinical specimen would you take if there was caries?

Answer 4

Specimen from occlusal surface swab.

Question 5

What methods could be used to detect the organism present?

Answer 5

PCR
Cell culture
DNA probes
NGS

Question 6

What bacteria is present in Periodontitis?

Answer 6

Porphyromonas Gingivalis- strict anaerobe
Prevotella Intermedia
Tannerrella Forsythia
Treponema Denticola

Question 7

What bacteria is present in Gingivalis?

Answer 7

Prevotella Intermedia
Fusobacterium Nucleatum
Actinomyces

Question 8

Describe the development of a plaque biofilm.

Answer 8

Adhesion
Colonisation
Accumulation
Complex community- nutrients can be shared, difficult to remove now
Dispersal

Question 9

What are the virulence factors of P.Gingivalis?

Answer 9

Fimbriae- help invade membrane vesicles of host cells by binding to cellular integrals

Endotoxin- LPS

Proteases

Capsular polysaccharide and outer membrane vesicles

Gingipains

Question 10

If you wanted to try determine the bacteria present in perio disease of a patient, what would you do?

Answer 10

Take a sample of plaque from the gingival margin and subgingivally of the worst site- use a paper point.

Question 11

What are the 4 types of oral candidiasis?

Answer 11

Pseudomembranous- thrush
- can be rubbed off.

Erythematous- atrophic, denture related

Hyperplastic- candidal leukoplakia
- looks like lichen planus.
- The hyphae invade the tissues and grow inside- cannot be wiped off.

Angular Cheilitis- hyphae interact with gram positive bacteria.

Question 12

What treatment would be used for Angular Cheilitis?

Answer 12

Topical miconazole cream- 2% 20g tube- apply to angles of the mouth twice a day.

If someone cannot use miconazole
- Prescribe sodium Fusidate ointment 2%, 15g tube, apply to angles of the mouth 4 times a day.

Question 13

Why might someone get a candida infection?

Answer 13

Immunocompromised- chemotherapy, radiotherapy, HIV, diabetes

Steroid inhaler

Poor denture hygiene

Patients with nutritional deficiency

Question 14

What treatment is advised for pseudomembranous candidiasis?

Answer 14

Local measures first- OHI, if taking corticosteroid inhaler then rinse mouth out after using it, Chlorhexidine mouthwash 0.2%.

Fluconazole capsules 50mg- 1 capsule per day for 7 days.

or

Nystatin- oral suspension 100,000 units/ml.

Question 15

Describe Newton’s classification of denture stomatitis.

Answer 15

Type 1- localised inflammation

Type 2- Diffuse inflammation

Type 3- Granular inflammation

Question 16

What fungal species are responsible for candida infections?

Answer 16

Candida albicans- sensitive to fluconazole and miconazole

Candida Glabrata- not sensitive to azaleas.
- Must use Nystatin instead.

Question 17

Describe the pathogenesis of Candida.

Answer 17

Adhesion
Colonisation
Hyphal penetration and invasion
Vascular dissemination
Endothelial colonisation and penetration

Question 18

How do Azoles work?

Answer 18

Inhibit the synthesis pathway so ergosterol isn’t synthesised.

Question 19

How do polyenes work?

Answer 19

Bind directly to ergosterol and make pores in it so that the cell contents leak out and cause the fungus to die.

Question 20

What types of bacteria are present in primary and secondary endodontic lesions?

Answer 20

Primary infection- gram negative bacilli

Secondary infection- E.Faecalis