Dentosphere : World of Dentistry

# Dentinal tubules are : A. Concave B. Straight C. S-Shaped D. None of the above # The cells that form secondary dentin are: A. Cementoblasts B. Fibroblasts C. Odontoblasts D. Osteoblasts # Dead tracts in ground section appears as: A. Dentinal tubules B. Coarse fibril bundles arranged at right angle to the dentinal surface C. Black in transmitted light and white in reflected light D. White in transmitted light and dark in reflected light

# Chemico-parasitic theory of dental caries is proposed by : A. G.V. Black B. Miller C. Gottlieb D. Schwartz # Which of the following organisms is found in deep carious lesions rather than in incipient lesions ? A. Streptococci B. Lactobacilli C. Veillonella D. Bacteroides # Pioneer bacteria in dental caries are in: A. Enamel B. Dentin C. Pulp D. Cementum # 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 # Ammonia causes: A. increase in plaque formation B. increase in calculus formation C. decrease in plaque formation D. precipitation of salivary proteins # Cavity formation in a tooth, due to dental caries is due to: A. Destructive potential of Streptococcus mutans B. Destructive potentia...

# Streptococcus mutans is considered to be a principal etiologic agent of caries because it produces acid and it: A. forms a gelatinous matrix B. metabolizes substrate from saliva C. derives energy from enamel constituents D. lives symbiotically with lactobacillus # Miller put forth the acidogenic theory of dental caries in the year: A. 1890 B. 1920 C. 1924 D. 1980 # 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 # Initiation of dental caries depends upon: A. formation of large amount of acid B. availability of carbohydrate food C. viscosity of saliva D. Localisation of acid over tooth surface # Caries, all are true except: A. Lactobacillus is the main causative organism in plaque B....

# Streptococcus mutans is involved in dental caries initiation. Other bacteria also involved is: A. S. sarcinus B. S. macae C. S. sanguis D.S. salivarius # The dietary carbohydrate most likely involved in etiology of dental caries is : A. Glucose B. Sucrose C. Dextran D. Polysaccharide # Bacteria responsible for initiation of caries is : A. Actinomyces B. Streptococcus mutans C. Lactobacillus D. Streptococcus viridans # What is the pH at which initiation of caries begins? A. 4.3-4.5 B. 5.2-5.5 C. 4.9-5.1 D. 3.5-4.5 # Oral foci of Miller's are seen in : A. Dental caries B. Lichen planus C. Herpes simplex D. Syphilis # In the earliest stages of carious lesion, there is loss of : A. Enamel cuticle B. Interprismatic substance C. Organic matrix D. Enamel lamellae # Smooth surface caries is characterized by spread of carie...

# Lactobacilli are numerous in carious lesions because they: A. Are the main causative agent B. Can produce insoluble extracellular polysaccharides C. Can attach to smooth enamel surfaces D. Are secondary invaders # 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

# Morphological stages of tooth development are explained based upon: A. Shape of enamel organ B. Shape of tooth germ C. Functions of enamel organ D. Shape of dental papilla # The disturbances occured during "calcification" stage of tooth development is seen in: A. Peg laterals B. Microdontia C. Supernumerary tooth D. Interglobular dentin # Tooth develops from: A. Ectoderm, mesoderm B. Ectoderm C. Mesoderm D. Ectoderm and endoderm # Which of the following is not an ectomesenchymal derivative? A. Dentin B. Cementum C. Pulp D. Enamel # The relationship between the pulpal and periodontal tissue complex beegins during dental development at: A. Adolescent stage B. 5-10 years C. Embryonic stage D. None of the above # In cap stage, regulating factor for cusp shape formation is present in: A. Dental papilla B. Dental follicle C. Inne...

# High levels of albumin is present in: A. Inner enamel epithelium B. Outer enamel epithelium C. Stellate reticulum D. Stratum intermedium # Nutrition for ameloblasts after the first layer of enamel is formed is: A. Dental sac B. Odontoblastic process C. REE D. Dental Papilla # Membrana preformativa is seen in: A. Bell stage B. Cap stage C. Bud stage D. Advanced bell stage # Enamel pearls are found in: A. Occlusal surface of premolars B. Furcation areas of permanent molars C. On the incisal edges of incisors D. None of the above # Which statement is correct ? A. Enamel cannot form in absence of dentin B. The formation of enamel and dentin are independent of each other C. Enamel formation can occur in absence of dentin D. None of the above # Atypical or osteodentin is formed due to disturbance during : A. Morphodifferentiation B. Histodiff...