NATIONAL BOARD PART I SAMPLE TEST ITEMS

The following 40 test items are representative of the four disciplines in the National Board Part I Dental Examinations: Anatomic Sciences, Biochemistry-Physiology, Microbiology-Pathology and Dental Anatomy and Occlusion. There is only one correct or best response for a test item. During testing, it is best to guess than leave an answer blank; there is no penalty for guessing wrong.

ANATOMIC SCIENCES

1. Which of the following blood elements is a fragment of megakaryocytic cytoplasm? 5. The muscularis externa contains some striated muscle in the A. Platelet B. Normoblast A. ileum. C. Erythrocyte B. stomach. D. Promyelocyte C. appendix. E. Proerythroblast D. esophagus. E. urinary bladder.

2. Which of the following cells is MOST likely to contain an abundant amount of rough- 6. Vessels supplying blood to the walls of large surfaced endoplasmic reticulum? are collectively known as

A. Pericyte A. arterioles. B. Macrophage B. capillaries. C. Osteoblast C. vasa vasorum. D. Endothelial cell D. metarterioles. E. Lymphocyte E. glomus.

3. Which of the following is the prime muscle 7. The one calcified structure of a tooth in retracting and elevating the mandible? incapable of continued growth after eruption is the A. Masseter B. Digastric A. enamel. C. Mylohyoid B. dentin. D. Temporalis C. . E. Lateral pterygoid D. true denticle.

4. A patient has a profound disturbance in 8. Which of the following is the first formed equilibrium, alterations of gait (ataxia), and portion of the dentin? intention tremor. This patient MOST likely has a massive lesion that involves which of A. Circumpulpal the following? B. Intertubular C. Transparent A. Amygdala D. Reparative B. Cerebellum E. Mantle C. Cerebral cortex D. Caudate nucleus E. Lenticular nucleus

9. Which of the following represents the 10. Each of the following PDL fiber groups is posterior boundary of the oral cavity and found in association with a central incisor the anterior boundary of the ? EXCEPT one. Which one is this EXCEPTION? A. Tonsil B. Soft A. Apical C. Dorsum of the B. Oblique D. C. Horizontal E. D. Alveolar crest E. Interradicular

BIOCHEMISTRY-PHYSIOLOGY

1. Hypoglycemia results from the excessive 4. Which of the following vitamins is MOST secretion of likely to be involved with bone loss in the elderly? A. glucose. B. insulin. A. Vitamin A C. glucagon. B. Niacin D. cyclic-AMP. C. Thiamine E. epinephrine. D. Vitamin D E. Vitamin E

2. The fluoride concentration in body fluids is regulated principally by which of the following? 5. Gout is a disease of purine overproduction. In this disease, joints develop crystals of A. Hormonal action B. Bone resorption and kidney tubular A. urea. secretion B. adenine. C. Simple skeletal exchange and C. guanine. resorption of bone D. hypoxanthine. D. Skeletal uptake and soft tissue E. sodium urate. deposition E. Skeletal uptake and renal excretion

6. The MOST susceptible sites in the nervous system for the effects of acute ishemic 3. Which of the following amino acids is a anoxia are the precursor for epinephrine? A. motor end-plates. A. Valine B. sensory receptors. B. Leucine C. synapses in autonomic ganglia. C. Tyrosine D. synapses in the central nervous s D. Cysteine system. E. Tryptophan

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BIOCHEMISTRY-PHYSIOLOGY (continued)

7. An enzyme increases the rate of a 9. Anemia is frequently associated with a biochemical reaction by deficiency of

A. decreasing substrate concentration. A. vitamins A and D. B. decreasing activation energy. B. vitamins C and D. C. increasing Km. C. vitamins E and K. D. increasing Keq. D. vitamin B12 and folic acid. E. increasing released free energy. E. thiamine, riboflavin, and niacin.

10. Each of the following is an important 8. Excluding the effect of drugs, apnea function of saliva EXCEPT one. Which occurring after hyperventilation of an one is this EXCEPTION? anesthetized patient results from A. Provides buffering action A. decreased demand for oxygen. B. Facilitates deglutition B. increased cerebral blood flow. C. Initiates protein digestion C. decreased carbon dioxide tension. D. Prevents demineralization D. increased hydrogen ion concentration. E. Enhances flavor E. decreased oxygenation of carotid bodies.

MICROBIOLOGY-PATHOLOGY

1. What are the "sulfur granules" found in 3. The aerosol produced during operative actinomycotic lesions? dental procedures is likely to contain a predominance of which of the following? A. Uric acid crystals B. Coagulated pus cells A. Yeasts and spirochetes C. Calcified necrotic tissue B. Spirochetes and rod forms D. Colonies of the infecting organism C. Spirochetes and rickettsiae E. Agglutinated platelets and D. Gram-positive rods and cocci lymphocytes E. Gram-negative rod forms and spirochetes

4. Ten days after being hospitalized for a large, 2. Which organ is the MOST susceptible to incapacitating myocardial infarct, a 50-year- infarction due to systemic arterial old man suddenly develops a paralysis of the thromboembolism? right side of his body. Which of the following BEST explains the damage to his A. Brain brain? B. Heart C. Liver A. Rupture of a congenital aneurysm of D. Colon the circle of Willis E. Lung B. Brain abscess from necrosis of myocardium C. Formation of a bacterial embolus from the pulmonic valve D. Embolization of a mural thrombus from the right ventricle E. Detachment of a mural thrombus from the left ventricle

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MICROBIOLOGY-PATHOLOGY (continued)

5. Which of the following conditions represents 8. Fluoride affects the metabolism of oral bacteria an intoxication rather than an infection? by inhibiting an enzyme in which of the following pathways? A. Anthrax B. Botulism A. Glycolytic C. Chancroid B. Folic acid D. Bacteroidosis C. Citric acid E. Salmonellosis septicemia D. Aspartate biosynthetic D. Extracellular polysaccharide

6. Which of the following organs possesses the greatest capacity for regeneration? 9. Which component of the HIV virus is inhibited by AZT treatment? A. Lung B. Liver A. gP120 C. Heart B. ss RNA genome D. Brain C. ds DNA genome E. Kidney D. Viral receptor E. Reverse transcriptase

7. In contrast to an exudate, a transudate has a 10. Which of the following represents the virus A. cloudy appearance. MOST likely to pass the placenta and produce B. higher specific gravity. congenital defects in the fetus? C. lower protein concentration. D. larger number of erythrocytes. A. Mumps E. characteristic cellular component. B. Rubella C. Rubeola D. Variola E. Varicella

DENTAL ANATOMY AND OCCLUSION

1. Which of the following newly erupted teeth is 2. Which of the following maxillary anterior MOST likely to exhibit only one pulp horn? teeth has a mesiodistal crown width that is greater than the incisocervical height? A. #31 B. #28 A. Primary central incisor C. #19 B. Primary lateral incisor D. #15 C. Central incisor E. #5 D. Lateral incisor E. Canine

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DENTAL ANATOMY AND OCCLUSION (continued)

3. How many pulp horns are usually present in a 7. The anatomy of the mesial surface of which typical primary mandibular first molar? of the following teeth is MOST likely to cause difficulty in restorative dentistry? A. 1 B. 2 A. Maxillary central incisor C. 3 B. Maxillary first premolar D. 4 C. Maxillary second premolar E. 5 D. Mandibular first molar

4. Considering root morphology, which of the 8. Which of the following describes the following teeth MOST readily lend themselves anatomic progression from mandibular first to to rotation during extraction? third molars?

A. Maxillary central incisor A. The roots become more divergent. B. Mandibular central incisor B. The crowns and roots become longer. C. Mandibular lateral incisor C. The crowns and roots become shorter. D. Maxillary first premolar D. The crowns become longer, but the E. Mandibular canine roots get shorter. E. The crowns become shorter, but the roots get longer. 5. Which of the following are the tissues immediately adjacent to the periodontal ligament? 9. A female child's primary first molars and primary incisors have erupted, but the A. Dentin and lamina dura primary canines and primary second molars B. Cementum and alveolar bone remain unerupted. What is the child's C. Gingiva and alveolar plate approximate age in months? D. Bundle bone and intermediate plexus E. and cortical bone A. 7 B. 10 C. 13 D. 16 6. Which of the following offers the greatest E. 20 degree of protection for , , and tongue? 10. Which of the following devices accurately A. Saliva locates the hinge axis position of the B. Adjacent contact of teeth mandible? C. Horizontal overlap (overjet) D. Deflecting function of ridges A. Kinematic face bow E. Sensory function of the periodontal B. Arbitrary face bow ligament C. Wax recording device D. Average value face bow E. Arcon articulator recorder

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National Board Dental Examination Part I Sample Test Items Answer Key

Anatomic Sciences Microbiology-Pathology

1. A 1. D 2. C 2. A 3. D 3. D 4. B 4. E 5. D 5. B 6. C 6. B 7. A 7. C 8. E 8. A 9. E 9. E 10. E 10. B

Biochemistry-Physiology Dental Anatomy and Occlusion

1. B 1. B 2. E 2. A 3. C 3. D 4. D 4. A 5. E 5. B 6. D 6. C 7. B 7. B 8. C 8. C 9. D 9. C 10. C 10. A

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