221. Dentin formed through out the life is______________? A. Sclerotic dentin B. Secondary dentin C. Reparative dentin D. All of the above ✅ The correct answer is option B. Secondary dentin.
222. The organic lining of the calcified dentinal tubules is known as_______________? A. Lamina propria B. Lamina lucida C. Lamina limitans D. Lamina densa ✅ The correct answer is option C. Lamina limitans.
223. Ameloblasts is______________? A. A cell from which tooth enamel is formed: B. A tissue from which tooth erupts C. A tumour of the jaw D. Pertaining to dentin ✅ The correct answer is option A. A cell from which tooth enamel is formed:.
224. The first sign of future deciduous teeth as a thickening of oral ectoderm appears at about_____________? A. 25th day of Intra uterine life B. 34th day of Intra uterine life C. 56th day of Intra uterine life D. 20 wks of Intra uterine life ✅ The correct answer is option C. 56th day of Intra uterine life.
225. An enzyme present in saliva which causes cell wall lysis____________? A. Lysozhyme B. Peroxidase C. Lactoferin D. Hyaluronidase ✅ The correct answer is option A. Lysozhyme.
226. Epithelial attachment is derived from____________? A. Reduced enamel epithelium B. Dental papilla C. Inner enamel epithelium D. Dental sac ✅ The correct answer is option A. Reduced enamel epithelium.
227. The plexus of Rashkov is present in which of the following zones in pulp ? A. Cell free zone B. Cell rich zone C. Odontoblastic zone D. Pulp core ✅ The correct answer is option A. Cell free zone.
228. Oral tissue for microscopic examination is prepared by_______________? A. Embedded in paraffin and sectioned B. Embedded in paradion and sectioned C. Frozen and sectioned D. Specimens ground into thin sections ✅ The correct answer is option E. All of the above.
229. The 2nd most prominent cells in pulp are______________? A. Fibroblasts B. defense cells C. Odontoblasts D. Histocytes or resting wandering cell ✅ The correct answer is option C. Odontoblasts.
230. Second arch derivatives are all except_________________? A. Stapes B. Malleus and incus C. Styloid process D. Superior part of hyoid bone ✅ The correct answer is option B. Malleus and incus.