OBI 2019 MCQ FINAL PDF

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2019 FINAL 1. Ossification of the mandible starts in which of the following areas? a. Alveolar process b. Condyle c. Coronoid d. Mental foramen e. Symphysis 2. The fetal stage as opposed to the embryonic stage of development is noted for: a. Differentiation of major external structures b. Induction of major internal structures c. Growth and maturation d. Extreme vulnerability to congenital defects 3. Which of the following supports the primitive embryo and is derived from ectoderm alone? a. Notochord b. Prechordal plate c. Secondary yolk sac d. Cardiac plate 4. Differentiation of ameloblasts takes place from which part of the tooth germ? a. Inner enamel epithelium b. Outer enamel epithelium c. Reduced enamel epithelium d. Stellate reticulum e. Stratum Intermedium 5. When the embryo folds (rostro-caudal) during development, which critical event takes place? a. Formation of the neural tube b. Formation of the stomatodeum c. Segmentation of the hindbrain d. Segmentation of the paraxial mesoderm 6. The roots of which permanent teeth are normally completely formed by age 10yrs a. Lower canine b. Lower second premolar c. Upper canine d. Upper central incisor 7. Embryonic connective tissue in the head and neck region is known as: a. Mesoderm b. Mesenchyme c. Ectoderm d. Ectomesenchyme 8. The highest quantity of inorganic content is present in which of the tissues related to teeth? a. Cementum b. Dentin c. Enamel d. Periodontal ligament

e. Pulp 9. Which of the following syndromes occurs due to failure of the neural crest cells to migrate properly to the facial region? a. Down syndrome b. Foetal alcohol syndrome c. Treacher Collins syndrome d. Asperger syndrome 10. During the production of enamel which of the following parts of the enamel organ disappears? a. Inner enamel epithelium b. Outer enamel epithelium c. Reduced enamel epithelium d. Stellate reticulum e. Stratum Intermedium 11. The first branchial arch gives origin to the: a. Muscles of mastication b. Muscles of facial expression c. Facial nerve d. Glossopharyngeal nerve 12. Which of the following structures are formed when the maxillary process merges with the lateral nasal process? a. Olfactory placodes b. Parathyroid gland c. Nasolacrimal duct d. Primary palate 13. During the fusion of any processes to occur, there is elimination of: a. Ectomesenchymal core b. Epithelial covering c. Neural crest migration d. Mesodermal features

14. Due to its developmental origin, the tongue is innervated by: 1. Fifth cranial nerve 2. Ninth cranial nerve 3. Twelfth cranial nerve 4. Branches of the 2nd and 7‘h cranial nerve a. 1 & 3 b. 2 & 4 c. 1, 2 & 3 d. 1 15. Teratogenic agents usually exert their effects during the stages of: a. Induction b. Induction and morphogenesis c. Morphogenesis and histodifferentiation d. Growth and maturation

16. Dental follicle cells: a. Differentiate into the ameloblast layer b. Differentiate into the odontoblast layer 0. Are derived from the vestibular lamina e. Migrate to the dentine surface and differentiate into cementoblasts 17. The dental lamina: a. Develops from the primary epithelial band b. Connects the cap stage tooth to the oral epithelium c. Undergoes apoptosis during the bell stage d. Is an epithelial structure e. All of the above 18. Osteoclasts: 1. Are mononucleated cells 2. Adhere to bone via a sealing zone 3. Phagocytose chunks of bone 4. Form an extracellular lysozyme under their ruffled border a. l, 2 & 3 b. l & 3 c. 2 & 4 d. All of the above statements are true e. None of the above statements are true 19. Changes in pulp during aging include: a. The chamber becomes smaller due to continued deposition of dentine b. Pulp is less sensitive because the number of nerve fibres decrease c. Pulp stones are likely to form d. There are more collagen bundles and fewer cells e. All of the above 20. The apical foramen is: a. Located at the cervix of the tooth b. The orifice for nerves and blood vessels to enter the pulp c. Formed from the vestibular lamina d. Found only in molars 21. The part of the alveolar bone that surrounds the root and gives attachment to the principal fibres of the PDL is... a. Alveolar crest b. Alveolar process c. Compact bundle bone d. Inner cortical plate e. Outer cortical plate 22. Which of the following is the most poorly developed cusp of the maxillary second molar? a. Mesiobuccal b. Mesiolingual c. Distobuccal d. Distolingual

23. The morphology of the crown of the tooth is determined at which of the following stages of tooth development? a. Bud stage b. Cap stage c. Bell stage d. Lamina stage e. Root sheath stage 24. The steepest cusp incline is present in which of the following permanent teeth? a. Maxillary first molar b. Maxillary first premolar c. Mandibular first molar d. Mandibular first premolar e. Mandibular second molar 25. A 20-year-old man chips the incisal edge of his 11, reducing the length of his crown. His dentist informs him that the tooth will erupt a little to compensate. This tooth movement is likely to result in an increase in the size of which of the following dental tissues. a. Cementum b. Dentin c. Enamel d. Periodontal ligament e. Pulp 26. A patient complains of loss of taste, and a numb sensation in the left half of his tongue, after removal of his left lower wisdom tooth. Which of the following nerves is most likely to have been injured during removal of this tooth? a) Facial nerve b) Glossopharyngeal nerve c) Inferior alveolar nerve d) Lingual nerve e) Mandibular nerve 27. At the age of nine years, the mandibular permanent first molar has its distal contact with which of the following teeth? a) First premolar b) No distal contact c) Second deciduous molar d) Second permanent molar e) Second premolar 28. Which of the following does not occur in the active phase of tooth eruption: a- Organization of a periodontal ligament from the dental follicle. b- Gradual separation of attachment epithelium fiom the enamel surface. c- Root formation. d- Occlusal wear 29. Which of the following terms may be used to indicate the dentin formed first in the tooth? a) Granular Dentin b) Hyaline Dentin

c) Mantle Dentin d) Primary Dentin e) Radicular Dentin 30. Differentiation of ameloblasts from the internal enamel epithelium takes place in which of the following stages of tooth development? a) Bud b) Cap c) Early bell d) Eruption e) Late bell

31. The identifying number of the permanent mandibular left second molar in the FDI numbering system is: a) 2 b) 17 c) 18 d) 37 e) 52 32. Which of the following sequence of eruption of permanent teeth is normally seen in the maxilla? a) 1,6,2,4,3,5,7,8 b) l,6,2,3,4,5,7,8 c) 6,1,2,4,3,5,7,8 d) 6,1,2,3,4,5,7,8 e) 6,2,1,3,4,5,7,8 33. A Y shaped occlusal groove is most likely to be present in which of the following teeth? a) Deciduous premolars b) Mandibular first premolar c) Mandibular second premolar d) Maxillary first premolar e) Maxillary second premolar 34. Concrescence is: a- An extra root or accessory roots in a formed tooth. b- Distorted root or roots in a formed tooth. c- A union of root structure of two or more teeth through cementum only. d- A spherical projection on the cemental root surface 35. Which of the following induces the dental papilla cells to be differentiated into odontoblasts? a- Stratum intermedium. b- Reduced enamel epithelium. c- Inner enamel epithelium. d- Outer enamel epithelium. 36. Which of the following is not a functional activity of the enamel organ: a- Inducing the differentiation of Odontoblasts. b- Secretion of enamel matrix.

c- Maturation of enamel. d- Formation of cementum 37. All of the following is the functions of The Stellate Reticulum except: a- Keep space for enamel development. b- Act as a reservoir for nutritive materials. c- Act as a cushion to protect ameloblasts. d- Secretes alkaline phosphatase enzyme 38. The down growth of an epithelial thickening buccal to the dental lamina is known as: a- Vestibular lamina. b- Linguo-alveolar Sulcus. c- Lateral dental lamina. d- Successional dental lamina 39. Calcified tissues of the tooth are derived from: a- Ectoderm only. b- Endoderm only. c- Mesoderm only. d- Ectoderm & Mesoderm. 40. The embryo's stomodeum is lined by: a- Ectoderm. b- Endoderm. c- Mesoderrn. d- Ectomesenchyme. 41. The ectomesenchymal cell condensation just beneath the enamel organ is called: A - Dental sac. B - Dental follicle. C - pulp. D - Dental papilla 42. Which of the following is not component of the enamel organ? a- Ameloblasts. b- Odontoblasts. c- Outer enamel epithelium. d- Stratum intermedium. 43. Actual eruptive movements of tooth occur mainly in a: a) Horizontal direction. b) Complex pattern. c) Axial direction. d) Rotational direction. 44. All of the following statements about the eruption of a permanent tooth and the exfoliation of its predecessor is true, except: A. Prior to eruption, the permanent tooth is completely formed. B. Resorption of deciduous roots is an intermittent process. C. Earliest resorption of deciduous roots is on root surface, facing the permanent tooth. D.Eruptive movements of the permanent tooth may not be solely responsible for deciduous root resorption

45. Cells of which germ layer are not present in the oropharyngeal membrane? a. Ectoderm b. Mesoderm c. Endoderm d. All are present 46. The first permanent anterior tooth to erupt is the: a. Maxillary central incisor b. Mandibular cuspid c. Mandibular lateral incisor d. Mandibular central incisor e. Maxillary cuspid 47. Which of the following does contribute to the formation of the upper lip? A- Lateral nasal process. B- Two maxillary processes & medial nasal process. C- Medial nasal process. D- First branchial arch. 48. The malleus of inner ear originates from: a- Condylar cartilage. b- Coronoid cartilage. c- Meckel’s cartilage. d- None of the above. 49. A unilateral cleft lip is formed when: a-The palatal shelves remain in a vertical position. b-The buceo-nasal membrane ruptures. c-One maxillary process fails to fuse with the medial nasal process. d- One lateral nasal process fails to fiise with the maxillary process. 50. During tooth eruption, bone formation is often seen at the base of socket. This newly formed bone is usually in the form of: a- Coarse fibered woven bone. b- Compact bone. c- Radiating bone. d- Horizontal trabeculae. 51. Shedding is predominantly the: a. Physiologic loss of impacted teeth. b. Pathologic loss of non-vital primary teeth. c. Physiologic loss of permanent teeth. d. Physiologic loss of primary teeth. 52. Cementoblasts: a- Are derived from the dental papilla. b- Secrete both collagen and glycosaminoglycans. c- Are multinucleated cell. d- May become incorporated into acellular cementum 53. Human teeth contain varities of cementum: a. acelllular extrinsic fiber cementum.

b. cellular intrinsic fiber cementun. c. mixed stratified cementum. d. all of the above. 54. As a result of aging, the dental pulp in human permanent teeth: a. Increase in size and becomes more vascular. b. Becomes less cellular and more fibrous. c. Becomes more cellular and contains more ground substance. d. Becomes more vascular and contains larger neural elements. 55. A false denticle: a-Consists of dentinal tubules. b-Is usually associated with a dead tract. c-Indicates a dead or dying pulp organ. d-Consists of concentric layers of calcification 56. The PDL fibers running between two adjacent teeth: a. Belong to the demo-alveolar group. b. Are gingival fibers. c. Are transseptal fibers. d. Are oxytalan fibers 57. Which of the following is not present in the periodontal ligament? a-Epithelial rests of Malassez. b-Fibroblasts. c-Cementoblasts. d- Osteocytes 58. The periodontal ligament is formed of: a. Fibers only b. Cells only c. Ground substance only d. All of the above 59. Which of the following groups of tissues comprise the periodontium? a-Alveolar bone, periodontal ligament, cementum. b-Periodontal ligament, cementum, gingiva. c-Cellular cementum, periodontal ligament, alveolar bone. d-Cementum, alveolar bone, periodontal ligament, gingiva. 60. The epithelial root sheath of Hertwig disintegrates: a. After odontoblastic differentiation & before dentin matrix formation. b. After odontoblastic differentiation & dentin matrix deposition. c. Before odontoblastic differentiation. d. After cementum formation. 61. The plexus of Raschkow is: a. A group of nerves located within the enamel layer b. A group of nerve endings in the dental organ c. A periodontal ligament structure which senses tooth movement d. Found in the pulp adjacent to the odontoblast layer e.C and D

62. A 13-year-old boy presents to his dentist with a fractured central incisor. On examination, the enamel has chipped off leaving exposed dentine. He complains of pain. Which of the contents of the dentinal tubule are most likely to be the cause of the pain? a. Collagen b. Fluid c. Nerve endings d. Odontoblastic processes e. Proteoglycans 63. Pulp is a tissue whose vitality is very fragile for the following reasons: 1. It is completely surrounded by dentin 2. The apical opening is very narrow 3. The exudate that follows hyperaemia perpetuates itself 4. It does not contain defence cells a. 1,2&3aretrue b. 1 & 3 are true c. 2 & 4 are true d. All of the above are true e. None of the above is true 64. Merkel cells are most likely to be found in which of the following tissues? a. Epithelium b. Papillary lamina propria c. Periosteum d. Reticular lamina propria e. Submucosa 65. Submucosa is found most commonly in which type of oral tissue: a. Lining mucosa b. Masticatory mucosa c. Specialized mucosa 66. A poorly informed dentist notes clusters of light yellow spots on an adult patient’s buccal mucosa. He performs a biopsy of the spots. The path report comes back as ‘Fordyce’s grannies composed of: a. Salivary glands b. Eccrine sweat glands c. Hair follicles d. Sebaceous glands e. Membrane coated granules 67. The majority of cells in non-keratinized stratified squamous epithelium are: a. Langerhans’ cells b. Merkel cells c. Keratinocytes d. Lymphocytes e. Melanocytes 68. Which cell in oral stratified squamous epithelium is most important in immune responses? a. Langerhans’ cells b. Merkel cells c. Keratinocytes

e. Melanocytes 69. Which nerves take part in the sensory innervation (taste)of the tongue? 1. XII 2.VII 3.V 4.IX a. 1,2 & 3 are true B.1 & 3 are true c. 2 & 4 are true d. All of the above statements are true e. None of the above statements are true

70. Which statement(s) is are true? 1. The mucosa of the soft palate contains fat and salivary glands 2. In the hard palate the oral mucosa is directly attached to underlying bone 3. Lymphoid nodules can be present in the posterior third of the tongue 4. 'The alveolar mucosa contains dense connective tissue a.1,2 & 3 B.2 & 4 c.1 & 4 d. All of the above statements are true...