oral histology Mcqs
151. Transmission of stimulus across dentin is______________?
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A. Stimulus induced fluid flow

B. There is no transmission of stimulus across dentin

C. Direct activation of nerve endings

D. Correlated with the innervation density of the dentin

152. Narrowing of periodontal ligament in labially placed mandibular canine with age is due to_____________?
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A. Down growths of gingival epithelium

B. Reversal of function of horizontal and oblique fibres

C. Gingival cysts formed from cell rests

D. Due to deposition of cementum and bone
153. Inorganic content of cementum is_____________?
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A. More than that of enamel

B. More than bone

C. Less than bone

D. Equal to that of bone

154. One of the following statement is unique about circumpulpal dentine______________?
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A. Contain phosphophoryn

B. Requires matrix vesicle for mineralization

C. Collagen fibers are oriented perpendicular to DEJ

D. Vonkorff fibers are present

155. Which of the following structures is not of ectodermal origin_______________?
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A. Enamel spindles

B. Hunter schreger bands

C. Enamel tufts

D. Enamel lamellae

156. Which of the following is least mineralized ?
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A. Cellular cementum

B. Acellular cementum

C. Cementoid

D. Incremental line

157. The percentage of inorganic matter in fully developed enamel is about____________?
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A. 76%

B. 86%

C. 96%

D. 66%

158. Hertwigs root sheath is formed from______________?
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A. Outer enamel epithelium

B. Stratum inter medium

C. Stellate reticulum

D. Cervical loop
159. The class of low molecular weight calcium binding proteins seen predominantly in developing enamel are_____________?
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A. Ameloplakin

B. Amelogenin

C. Enamelin

D. Tuftelin

160. The cells of the enamel organ which differentiate into future ameloblasts are_____________?
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A. Cells of inner enamel epithelium

B. Cells of stratum intermedium

C. Cells of stellate reticulum

D. Cells of outer enamel epithelium

161. Tooth develops from_______________?
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A. Ectoderm, mosoderm

B. Mesoderm

C. Ectoderm

D. Ectoderm and endoderm

162. The type of dentin that is formed prior to root completion______________?
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A. Circum pulpal dentin

B. Peritubular dentin

C. Secondary dentin

D. Inter tubular dentin

163. Width of PDL is_______________?
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A. 0.25 mm

B. 0.75 mm

C. 0.10 mm

D. 0.50 mm

164. The enamel has no capacity of self repair because______________?
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A. It has no direct connection with the active cells of the dental pulp

B. Its formative cells are lost once it is completely formed

C. It is essentially a keratin tissue and has no blood vessels

D. It has only a small percent of organic content

165. Intermediate cementum is___________?
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A. Apical third

B. Coronal third

C. Found at dentinocemental junction

D. Between enamel and cementum

166. Neonatal lines are found in all of the following except____________?
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A. Dentin of permanent mandibular incisors

B. Enamel of permanent canines

C. Enamel and dentin of permanent first molars

D. Enamel of primary incisors

167. Odontoblasts are derived from______________?
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A. Lymphocytes

B. Histocytes

C. Macrophages

D. Undifferentiated mesenchymal
168. Accessory canals result from____________?
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A. Adherent epithelial rests

B. Break in Hertwigs root sheath

C. Defects in cementogenesis

D. Dividing epithelial bridges

169. The formation of which of the following does not represent normal physiologiacl process of dentin formation_______________?
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A. All of the above

B. Tetiary dentin and sclerotic dentin

C. Primary and secondary dentin

D. Secondary dentin and circumpulpal dentin

170. Unmyelinated nerve fibres of pulp are____________?
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A. Respond to hot and cold

B. Sensory in nature

C. carry pain sensation

D. Associated with blood vessels and are sympathetic in nature
171. Nutrition for ameloblasts after 1st layer of enamel is laid is______________?
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A. Odontoblastic process

B. Dental sac

C. Ree

D. Dental Papilla

172. The main function of horizontal fibres of P.D ligament is____________?
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A. Prevent rotation

B. Maintains the mesiodistal width

C. Prevent extrusion

D. All of the above

173. The fibroblasts associated with capillaries are__________?
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A. Lymphocytes

B. Pericytes

C. Histocytes

D. Plasma cell

174. Width of the periodontal ligament is least at______________?
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A. Fulcrum of rotation

B. Apical third

C. Cervical third

D. It has uniform width

175. Enamel pearls are found in_____________?
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A. Occlusal surface of premolars

B. On the incisal edges of incisors

C. None of the above

D. Furcation areas of permanent molars
176. Size of pulp chamber____________?
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A. Increases with age

B. Increased in some cases and decreases in some cases

C. Decreases with age

D. None of the above

177. The most abundant principle fibre group in periodontal ligament is____________?
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A. Transeptal

B. Horizontal

C. Apical

D. Oblique
178. The hertwigs epithelial root shealth is essential to development of the root because it_______________?
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A. Remians as an essential constituents of the periodontal ligament

B. Given rise to odontoblasts that lay down dentin of the root

C. Moulds the shape of roots and stimulates differentiation of odontoblasts

D. Gives rise to cementoblasts that produce cementum of the root

179. Outer and inner enamel epithelium first seen in____________?
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A. Advanced bell stage

B. Bud stage

C. Bell stage

D. Cap stage
180. During the formation of primary teeth_______________?
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A. Dentin forms faster than enamel

B. Enamel forms faster than dentin

C. Enamel forms more cervically than dentin

D. Processes of their cells remain in content with each other

181. Cementum_____________?
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A. Does not contain collagen fibres

B. Often overlaps the enamel

C. Is derived from the sheath of hertwig

D. Is acellular in the apical third of the tooth

182. Disturbance during the morphodifferentition stage of tooth development will result in______________?
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A. Change in number of teeth

B. Ameloblastoma

C. Change in form and shape of the teeth

D. Hypoplasia

183. Incremental lines of Retzius appear_____________?
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A. As lines in the enamel running at right angles to the enamel surface

B. As lines in the dentin running at right angles to the dentino-enamel junction

C. In dentin and follow the appositional pattern

D. In enamel and follow the apposition pattern
184. Which of the following statement is true______________?
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A. The apical foramen is surrounded by cementum

B. Cementum is thinnest at CEJ (20-50?m)

C. Cementum is thickest towards the apex (150-200?m)

D. All of the above
185. Blunt cell processes seen on the developing ameloblasts are celled as________________?
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A. Tomes fibres

B. Tomes layer

C. Odontoblastic processes

D. Tomes processes

186. 1st formed dental tissue______________?
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A. Enamel

B. Bone

C. Dentin

D. Cementum

187. Inorganic content of cementum is______________?
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A. 60 to 65%

B. 45 to 50%

C. 55 to 60%

D. 50 to 55%

188. The 2nd most prominent cells in pulp are______________?
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A. defense cells

B. Odontoblasts

C. Fibroblasts

D. Histocytes or resting wandering cell

189. The primary response of the pulp to tissue destruction is_______________?
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A. Inflammation

B. Necrosis

C. Calcific degeneration

D. Ulceration

190. Morphological stages of tooth development are explained based on_____________?
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A. Function of enamel organ

B. Shape of enamel organ

C. Shape of dental papilla

D. Shape of tooth germ
191. Incremental lines of retzius are seen in______________?
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A. Dentin

B. Enamel

C. Pulp

D. Cementum

192. Maximum fluoride content is seen in_____________?
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A. Enamel

B. Dentin

C. Dental cementum

D. Dental pulp

193. Ratio of diameter of enamel rods in the DEJ to the enamel surface is______________?
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A. 2:01

B. 1:04

C. 1:02

D. 1:1
194. Hertwigs epithelial root sheath is made up of_______________?
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A. Hyaline layer of Hopewell-smill

B. Stratum intermedium

C. Stellate reticulum

D. Outer and inner enamel epithelium
195. True about osteoclasts_____________?
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A. All of the above are true

B. The plasma membrane of osteoclasts adjacent to bone that is being resorbed is known as striated or ruffled border

C. Contain lysosomes with acid phosphates

D. Monocytes are precursor cells of osteoclasts

196. Nutritional supply of the ameloblasts during most of their life cycle is from the_____________?
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A. Reduced dental organ

B. Odontoblastic processes

C. Dental sac

D. Dental pulp

197. Dentino enamel junction is_________________?
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A. Straight

B. Scalloped and the convexities are directed towards enamel

C. Scalloped and the convexities are directed towards dentin

D. Non-scalloped

198. Korffs fibres are seen in______________?
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A. Mantle dentin

B. Reactionary dentin

C. Secondary dentin

D. Indeed dermal tubules

199. All factors govering dentine permeability EXCEPT_______________?
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A. Smear layer

B. Length of dentinal tubules

C. Fluid convection

D. Diffusion coefficient

200. The vascular supply of the periodontal ligament is______________?
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A. A net like plexus that runs closer to the bone than to the cementum

B. Greatest in the middle-third of a multirooted tooth

C. Greatest in the middle-third of a single rotted tooth

D. A net like plexus that runs closer to the cementum than to the bone