451. What is the PH at which initiation of caries begin ?
A. 4.3-4.5
B. 5.2-5.5
C. 4.9-5.1
D. 3.5-4.5

452. The dietary carbohydrate most likely involved in etiology of dental caries in man is____________?
A. Glucose
B. Sucrose
C. Dextran
D. Polysaccharide

453. The correct order of microscopic zones of dentinal caries starting from the D.E junction is_______________?
A. Zone of sclerosis, decalcification zone, bacterial invasion
B. Bacterial invasion, decalcification zone, zone of sclerosis
C. Zone of sclerosis, bacterial invasion, decalcification zone
D. Decalcification zone, zone of sclerosis, bacterial invasion

454. Dental caries is associated with_____________?
A. Streptococcus agalactiae
B. Streptococcus mutans
C. Streptococcus bovis
D. Streptococcus anginosus

455. Which of the following is cariogenic ?
A. Selenium
B. Vanadium
C. Strontium
D. Molybdenum

456. Starch is considered to be less cariogenic than monosaccharides and disaccharides because it_______________?
A. Does not diffuse through plaque
B. Is rapidly hydrolysed in the mouth
C. Enhances remineralisation
D. Raises the PH in the oral cavity

457. Organism involved in smooth surface caries is____________?
1 Streptococcus mutans
2 Actinomyces viscosus
3 Lactobacillus
4 Campylobacter

A. only 1
B. only 2
C. 1 and 3
D. All of the above

458. The attachment of the Actinomyces species to the tooth surface is facilitated by____________?
A. Fimbriae
B. Cilia
C. Flagella
D. Pseudopodia

459. Which of the following factors in the stephan’s curve is related to the caries incidence and sugar intake______________?
A. Physical form of sugar
B. Frequency of sugar intake
C. Ph of Plaque
D. Quantity of sugar intake

460. Cavity formation in a tooth, due to dental caries is due to______________?
A. Destructive potential of streptococcus mutans
B. Destructive potential of lactobacillus acidophilus
C. Lateral spread of caries along DE junction and weakening of the outer covering enamel
D. Mastectomy force and unrelated to the extent of carious process