461. The most pronounced effect on the oral microflora of a reduction in rate of salivary flow is a_____________?
A. Significant increase in number of oral bacteria
B. Shift towards more acidogenic microflora
C. Significant decrease in number of oral bacteria
D. Shift towards more aerobic microflora
462. Which of the following organisms is found in deep carious lesions rather than in incipient lesions ?
463. Early invading bacteria in carious lesions are called___________?
B. Pioneer bacteria
C. Advancing bacteria
D. Anaerobic bacteria
464. The probable reasons for a high incidence of dental caries in the teenage population relates most directly to______________?
A. Rapid growth
B. Frequency of sucrose intake
C. Negligence in visiting the dentist
D. Carelessness in oral hygiene habits
465. The enzyme glucosyl transferase secreted by Streptococcus mutans sythesizes glucans from_____________?
466. For a bacterium to be seriously considered in the etiology of dental caries, it must______________?
A. Exist regularly in the dental plaque
B. Produce extracellular amylopectins
C. Be lethal for gnotobiotic animals
D. Produce intracellular dextrans
467. Streptococcus mutans is considered to be principle etiologic agent of caries because it produces organic acids and it ________________?
A. Forms a gelatinous matrix
B. Metabolizes substrate from saliva
C. Derives energy from enamel constituents
D. Lives symbiolically with lactobacillus
468. Which tooth in the permanent dentition is the most susceptible to dental caries ?
A. Maxillary 1st premolar
B. Maxillary 2nd molar
C. Mandibular 1st molar
D. Mandibular 2nd molar
469. Smooth surface caries is characterized by spread of caries in enamel and dentin as cones. These alignment in enamel and dentin is____________?
A. Base to base
B. Apex to base
C. Apex to apex
D. None of the above
470. Oral foci of miller’s are seen in_______________?
A. Dental caries
B. Lichen planus
C. Herpes simplex