Dental Science for Dental Assisting Exam Practice Problems

Practice Answers and Explanations

1. b. Anatomical crown. The anatomical crown is supragingival, above the gingiva and partially subgingival, below the gingiva. The clinical crown is the portion of the anatomical crown that is supragingival, above the gingiva and can be seen by a clinical examination.

2. c. Root. The root is what anchors the tooth into the alveolar bone.

3. a. Enamel. The enamel is the hardest tissue of the tooth and makes up the outermost layer of the crown.

4. c. Cementum. The cementum is the lining around the dentin in the root portion of the tooth. The cementum is attached to the periodontal ligament.

5. d. Pulp. The pulp is the innermost tissue of the tooth. It contains blood vessels and nerves and is sometimes referred to as the “heart” of the tooth.

6. e. Dentin. The dentin is the tissue underneath the enamel in the coronal portion of the tooth and under the cementium in the root of the tooth.

7. b. Dentin. The dentin is the tissue of which the root is mostly made. It is the largest layer of the tooth.

8. e. Alveolar process. The root of the tooth is embedded into the alveolar process or alveolar bone.

9. b. #3. The Universal Numbering System consists of #1–16 in the maxillary arch and #17–32 in the mandibular arch. The first molar in the maxillary right quadrant is #3.

10. d. The ISO Numbering System/International Standards Organization assigns a number to each quadrant in the permanent dentition and to each quadrant in the primary dentition. This quadrant number represents the first number. The second number relates to the tooth in the quadrant counting from the midline to the posterior of the mouth. There are eight teeth in each permanent dentition quadrant and five teeth in each primary dentition quadrant. Therefore, the permanent second molar is #7.

11. b. There are three major salivary glands in the human body. They are the parotid, the sublingual, and the submandibular glands.

12. c. The larynx is the scientific term for the voicebox. Without the larynx, humans could not speak.

13. b. The mandible is the bone of the lower arch. It is the only bone in the human skull that is movable.

14. b. There are two sets of teeth we call dentitions: the primary dentition and the permanent dentition.

15. c. A mixed dentition occurs in patients aged six to 12. During this age period, primary teeth are being exfoliated and permanent teeth are erupting, and both are present in the mouth at the same time.

16. a. There are two types of saliva in the human mouth: serous and mucous. Serous is considered normal saliva, and mucous, sometimes referred to as ropey saliva, is very thick.

17. d. There are five surfaces on every tooth. These surfaces are mesial, distal, occlusal/incisal, lingual, and buccal/facial.

18. c. The anterior portion of the mouth is located toward the face and consists of the central incisors, the lateral incisors, and the cuspids. The posterior portion of the mouth is located behind the anterior. It consists of the first and second bicuspids/premolars, and the first, second, and third molars.

19. a. The curve of Spee is also known as the curve of the occlusal plane. It forms a slight smile curve.

20. a. The triangular space above the contact just before the gumline is the embrasure.

21. a. The anterior naris is the scientific name for the nostril.

22. d. The cuspid is the longest rooted tooth in the permanent dentition and is located at the corner of the arch.

23. d. The Cusp of Carabelli is the name of the fifth cusp on the permanent maxillary first molar. It is located on the lingual surface.

24. c. There are 44 teeth developing when a baby is born.

25. c. The top of the tongue is referred to as the dorsal. The underneath side of the tongue is referred to as the ventral.

26. d. First bicuspids/premolars, second bicuspids/premolars, and third molars are not present in the primary dentition. The primary dentition consists of only five teeth in each quadrant: the central incisor, the lateral incisor, the cuspid, the first molar, and the second molar.

27. b. The smallest teeth in the permanent dentition are the mandibular central incisors. They are also the first permanent teeth to erupt into the mouth.

28. b. The clinical crown is the portion of the anatomical crown that is visible upon examination, above the gumline.

29. e. Drifting occurs when a tooth is missing and there is no contact for an opposing tooth. The two teeth on either side of the missing tooth drift toward the space, and the opposing tooth to the missing tooth supraerupts toward the space.

30. d. Periodontal disease is classified into five types. Type I is gingivitis. Types II through V are acute periodontitis, moderate periodontitis, advanced periodontitis, and refractory periodontitis.

31. b. In order for caries to develop, there needs to be a susceptible tooth, some bacteria, and fermentable carbohydrates.

32. c. The first stage of caries is incipient caries. This is when the caries begin to demineralize the enamel of the tooth.

33. a. Periodontal disease is the process of breaking down the periodontium. The periodontium consists of the gingiva, the epithelial attachment, the sulcus, the periodontal ligament, the cementum, and the alveolar bone. With periodontal disease, the periodontium is broken down, and there is a loss of tissue and destruction of the alveolar bone.

34. e. In America, 75% of the population have one form of periodontal disease.

35. c. Anorexia nervosa is an eating disorder that is characterized by self-starvation. Periodontal tissues are reduced, and the teeth are not as strong since the calcium intake is decreased by not eating.

36. a. Water is often referred to as the forgotten nutrient. The human body is approximately 80% water, which is needed to build tissues, regulate the temperature of the body, and lubricate the joints and mucous membranes. Saliva is made up of water, calcium, and phosphate, which can promote reminerialization of incipient caries.

37. d. Glossitis is the scientific term used to describe inflammation of the tongue.

38. b. When a patient undergoes radiation or chemotherapies and the salivary glands are affected, saliva can no longer be produced. The mouth becomes severely dry, and there is less blood supply sent to the tissues. This condition will aid in oral infection, delay any healing, and make it difficult to wear any dentures.

39. a. The human body consists of 206 bones.

40. d. The integumentary system includes the skin.

41. d. The dentinoenamel junction is where the enamel in the crown meets the underlying layer of dentin.

42. a. The cementoenamel junction is where the enamel that surrounds the crown meets the cementum that surrounds the root at the neck of the tooth.

43. b. The dentinocemental junction is where the dentin meets the layer of cementum on the root.

44. The eight surfaces of the teeth are shown in Figure 4.3 below.

45. The 14 structures of the oral cavity are shown in Figure 4.4 below.