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350 Quick Review Series: BDS 2nd Year
Part VI
Dental Microbiology
Topic 40
Dental Microbiology
SHORT ESSAYS
Q. 1. Cultural methods of Candida albicans Q. 2. Enumerate the clinical features of congenital
syphilis.
Ans. Methods used in laboratory diagnosis of Candida are
as follows: Ans. Congenital syphilis exhibits the following clinical
1. Direct examination: Scrapings from the lesions of skin, features:
nails or mucosa are examined in a wet film in KOH or
Gram-stained smear. The Candida albicans appears as 1. Hutchinson’s teeth (centrally notched, widely-spaced
budding yeast cells. peg-shaped upper central incisors)
2. Culture 2. Mulberry molars
a. Specimens are inoculated on the Sabouraud’s dex- 3. Frontal bossing
trose chloramphenicol agar medium at 25–37°C for 4. Saddle nose
24 h. Candida produces creamy white, smooth colo- 5. Poorly developed maxillae
nies with a yeasty odour. 6. Enlarged liver and spleen
b. The Candida albicans is identified by the following: 7. Anaemia
i. Germ tubes: When Candida is grown in human 8. Lymph node enlargement
serum at 37°C for 3 h a wet KOH film shows 9. Jaundice
filamentous outgrowths (Reynolds Braude phe- 10. Pseudoparalysis
nomenon). 11. Snuffles (rhinitis)
ii. Chlamydospores: These develop in a nutrition-
Q. 3. Name the microorganisms causing dental caries.
ally poor medium such as cornmeal agar at
28°C. Ans. Dental caries is a microbial disease that damages the
iii. Biochemical reactions: Candida albicans can be structure of teeth.
identified by the assimilation and fermentation
of sugar. Aetiology
iv. Serology: Candida albicans can also be identi-
fied by the precipitation test with a carbohydrate The common bacteria causing dental caries are Streptococ-
extract of group A antigens. cus mutans, Lactobacilli and actinomycosis, etc.
v. Antigen detection: It is done by ELISA and RIA
which detects cell wall manner or cytoplasmic Predisposing Factors
constituents. 1. Poor oral hygiene
vi. Skin test: Delayed hypersensitivity to Candida 2. Carbohydrates (sugars and starches)
extracts is a useful indicator of functional integ- 3. Habit of snacking in between meal time
rity of CMI.
vii. Animal inoculation: Candida albicans kills the
animal (rabbit, guinea pig and mice) in 4–5 days Pathogenesis
with typical renal abscess on intravenous inocu- 1. The bacteria act on all types of foods—especially
lation. sugar and starch and convert them into acids. Bacteria,
350 Quick Review Series: BDS 2nd Year
Part VI
Dental Microbiology
Topic 40
Dental Microbiology
SHORT ESSAYS
Q. 1. Cultural methods of Candida albicans Q. 2. Enumerate the clinical features of congenital
syphilis.
Ans. Methods used in laboratory diagnosis of Candida are
as follows: Ans. Congenital syphilis exhibits the following clinical
1. Direct examination: Scrapings from the lesions of skin, features:
nails or mucosa are examined in a wet film in KOH or
Gram-stained smear. The Candida albicans appears as 1. Hutchinson’s teeth (centrally notched, widely-spaced
budding yeast cells. peg-shaped upper central incisors)
2. Culture 2. Mulberry molars
a. Specimens are inoculated on the Sabouraud’s dex- 3. Frontal bossing
trose chloramphenicol agar medium at 25–37°C for 4. Saddle nose
24 h. Candida produces creamy white, smooth colo- 5. Poorly developed maxillae
nies with a yeasty odour. 6. Enlarged liver and spleen
b. The Candida albicans is identified by the following: 7. Anaemia
i. Germ tubes: When Candida is grown in human 8. Lymph node enlargement
serum at 37°C for 3 h a wet KOH film shows 9. Jaundice
filamentous outgrowths (Reynolds Braude phe- 10. Pseudoparalysis
nomenon). 11. Snuffles (rhinitis)
ii. Chlamydospores: These develop in a nutrition-
Q. 3. Name the microorganisms causing dental caries.
ally poor medium such as cornmeal agar at
28°C. Ans. Dental caries is a microbial disease that damages the
iii. Biochemical reactions: Candida albicans can be structure of teeth.
identified by the assimilation and fermentation
of sugar. Aetiology
iv. Serology: Candida albicans can also be identi-
fied by the precipitation test with a carbohydrate The common bacteria causing dental caries are Streptococ-
extract of group A antigens. cus mutans, Lactobacilli and actinomycosis, etc.
v. Antigen detection: It is done by ELISA and RIA
which detects cell wall manner or cytoplasmic Predisposing Factors
constituents. 1. Poor oral hygiene
vi. Skin test: Delayed hypersensitivity to Candida 2. Carbohydrates (sugars and starches)
extracts is a useful indicator of functional integ- 3. Habit of snacking in between meal time
rity of CMI.
vii. Animal inoculation: Candida albicans kills the
animal (rabbit, guinea pig and mice) in 4–5 days Pathogenesis
with typical renal abscess on intravenous inocu- 1. The bacteria act on all types of foods—especially
lation. sugar and starch and convert them into acids. Bacteria,
