Darby Histology and Embryology

CASE A

use for the next 12 questions

age: 5

gender: female

vitals: 90/60 bp, 85 pulse, 10 respiration

CC: mother concerned about dark spots on teeth. Child complains of dental pain when eating candy.

Social history: Entering kindergarten, plays soccer

Meds: rescue inhaler

Med history: diagnosis of asthma

Dental history: 1st dental appt

Ext/Intra findings: extraoral: wnl, Intraoral: several carious lesions on primary dentition 6-yr molars are partially erupted

Gingival examination: red tissue at gingival margins

Dentition: 20 primary teeth

Radiographic findings: interproximal carious lesions

Deposits: mod biofilm

CASE A

1. The tissue(s) that have nerve innervation are:

a. Dentin

b. Pulp and dentin

c. Pulp and periodontal ligament

d. Cementum

d. All of the above

c. Pulp and periodontal ligament

CASE A

2. The free unmyelinated nerve endings of the pulp can sense:

a. Hot

b. Cold

c. Pressure

d. Pain

e. All of the above

c. pressure

D. The free unmyelinated nerve endings of the pulp tissue can sense pain only. It cannot distinguish between hot or cold. It cannot distinguish the sensation of pressure. All stimuli are interpreted as a pain perception. The encapsulated nerve endings are responsible for registering pressure changes

CASE A

3. Nonsuccedaneous permanent molars develop from buds that grow from:

a. A successional dental lamina.

b. Primary tooth buds.

c. The posterior part of palatal shelves.

d. Extension of the primary second molar’s dental lamina.

d. Extension of the primary second molar’s dental lamina

D. Six permanent molars per dental arch develop from a posterior extension of the dental lamina

CASE A

4. What is the angled part of the ameloblast that secretes the enamel matrix?

a. Inner enamel epithelium

b. Repolarized preameloblasts

c. Tomes’ process

d. Disintegrating basement membrane

c. Tome’s process

CASE A

5. The pink labial mucosa or buccal mucosa meets the redder _____ at the mucobuccal fold.

a. Marginal gingiva

b. Attached gingiva

c. Alveolar mucosa

c. alveolar mucosa

CASE A

6. The outer cells of the dental papilla are induced to differentiate during tooth development into:

a. Pulp tissue

b. Preameloblasts

c. Odontoblasts

d. Cementoblast

c. odontoblasts

CASE A

7. Which stage of tooth formation occurs for the primary dentition during the 11th and 12th week of prenatal development?

a. Bell Stage

b. Initiation Stage

c. Cap Stage

d. Bud Stage

a. bell stage

CASE A

8. What is connective tissue derived from during prenatal development?

a. Ectoderm

b. Endoderm

c. Neural crest cells

d. Mesoderm

d. mesoderm

CASE A

9. Enamel _____form the crystalline structural unit of enamel.

a. Tubules

b. Granules

c. Rods

d. Cuticles

c. rods

CASE A

10. The patient’s mother was informed the multiple carious lesions caries on her maxillary molars had progressed into the dentin. Caries in the dentin of the tooth progresses through the

a. Interglobular dentin

b. Dentinal tubule

c. Secondary dentin

d. Predentin

b. dentinal tubule

CASE A

11. Enamel hypocalcification is a type of enamel dysplasia that involves:

a. an increased number of ameloblasts

b. reduction in the quantity of enamel matrix

c. grooves and pitting on the enamel surface

d. interference in the metabolic processes of ameloblasts

b. reduction in the quantity of enamel matrix

CASE A

12. During the 4th week of embryonic life, the tongue develops from several swellings arising on the internal aspect of brachial arches 1–4 (pouches). Which swellings form the body of the tongue?

a. Branchial arch 1

b. Branchial arches 2, 3, and part of 4

c. Branchial arch 4

d. Thyroid gland

a. branchial arch 1

CASE B (questions 13-25)

age: 10

gender: male

vitals: 110/60 BP, 80 pulse, respirations 14

CC: mother concerned about crooked teeth

social history: pt is entering grade 5. Plays a reed instrument

Medications: none

Medical history: pt is up to date with vaccinations

Dental history: pt had repaired cleft lip/palate

Gingival: coral, pink, stippled attached gingiva

Dentition: normal eruption pattern

Deposits: light supragingival calculus on lower anterior teeth

CASE B

13. What histologic structure(s) comprise(s) healthy attached gingiva?

a. Circular fibers

b. Rete pegs

c. Connective tissue papilla

d. Fibroblasts

e. All of the above

e. all of the above

CASE B

14. What type of epithelium comprises attached gingiva?

a. Keratinized stratified squamous epithelium

b. Nonkeratinized stratified squamous epithelium

c. Keratinized simple squamous epithelium

d. Pseudostratified columnar epithelium

e. Nonkeratinized simple squamous epithelium

a. keratinized (orthokeratinized) stratified squamous epithelium

CASE B

15. A cleft lip occurs when the maxillary process fails to fuse with which one of the following embryonic processes?

a. Palatine process

b. Globular process (medial nasal process)

c. Lateral nasal process

d. Mandibular process

e. Opposing maxillary process

b. globular process (medial nasal process)

cleft lip occurs whne the maxillary process fails to fuse with the globular process. The maxillary process forms the sides of the lip, and the globular process (medial nasal process) forms the center or philtrum of the lip can occur on one side or both sides

CASE B

16. Embryonically, the mandible is derived from the:

a. Stomodeum

b. First branchial arch

c. Frontal process

d. Second branchial arch

e. Third branchial arch

b. first branchial arch

CASE B

17. The anterior portion, or body, of the tongue develops from the:

a. Second branchial arch

b. Maxillary process

c. Mandibular process

d. Globular process (medial nasal process)

e. Rathke’s pouch

c. mandibular process

From the mandibular process (first branchial arch), two lateral swellings and one medial swelling (tuberculum impar) merge to form the tongue

CASE B

18. Which of the following orofacial structures is located in the midline of the face or neck?

a. Nasal Septum

b. Submandibular salivary gland

c. Naris and ala

d. Parotid salivary gland

a. nasal septum

CASE B

19. Continuous replacement of cells is characteristic of which type of epithelium?

a. Simple squamous

b. Stratified squamous

c. Pseudo-stratified columnar

d. Stratified transitional

b. stratified squamous

CASE B

20. When a cleft of the alveolar process is present, it occurs between the

a. First and second premolars

b. Central incisors

c. Lateral incisor and canine

d. Canine and first premolar

c. lateral incisor and canine

a cleft of the alveolar ridge results from the lack of fusion of the premaxilla, which forms the anterior portion processess (palatal shelves), which give rise to the posterior 2/3rds of the hard palate and contain maxillary canines and posterior teeth. The lines of fusion, therefore, fall between the laterals and the canine teeth

CASE B

21. The overlapping period between the primary and permanent dentition is considered the period of:

a. Primary

b. Secondary

c. Tertiary

d. Mixed

d. mixed

CASE B

22. During the cell cycle, interphase involves the cells engaging in:

a. Chromatin removal

b. Organelle replication

c. Centromere reduction

d. Substance destruction

b. organelle replication

within interphase engage in growth, metabolism, organell replacement, and substance production including chromatin replication

CASE B

23. Meckel’s cartilage is derived from neural crest cells which migrate cephalad and interact with cephalic ectoderm and mesoderm to result in the development of:

a. Facial skeleton

b. Neck Skeleton

c. Connective tissue components

d. Tooth development

CASE B

24. Each germ cell contains ____ chromosomes (haploid number); during the process of fertilization, the number is restored to ____ chromosomes (diploid).

a. 22, 45

b. 21, 44

c. 20, 43

d. 23, 46

d. 23, 46 haploid and diploid numbers

CASE B

25. Each tooth is the product of two tissues that interact during tooth development:

a. Epithelium, ectomesenchyme

b. Endoderm, epithelium

c. Ectomesenchyme, endoderm

d. Mesenchyme, ectoderm

a. epithelium, ectomesenchyme

CASE C (26-35)

Age: 30 

Gender: female

Vitals: 110/60 bp, pulse 70, respirations 12

cc: gingival recession

social history: teacher, mother of 2

Medications: birth control pills

Medical history: Gravida para two

dental history: regular dental tx, history of periodontal treatment

gingival: localised recession

dentition: history of orthodontic tx

perio charting: pocket depth 4-6mm, mod bleeding on probing

CASE C

26. A connective tissue graft from the hard palate area was recommended for the gingival recession. What type of epithelial tissue is in this area?

a. Nonkeratinized simple squamous epithelium

b. Keratinized simple squamous epithelium

c. Orthokeratinized stratified squamous epithelium

d. Pseudostratified columnar epithelium

e. Nonkeratinized stratified squamous epithelium

c. orthokeratinized stratified squamous epithelium

CASE C

27. A graft procedure would include a surgical flap in the epithelial tissue of the palate and harvesting the underlying connective tissue. The connective tissue would be placed in the recipient site. What type of connective tissue is usually found underlying the gingiva?

a. Loose connective tissue

b. Dense connective tissue

c. Mixed connective tissue

d. Cannot be determined

b. dense connective tissue

CASE C

28. All of the following tissues have little or no keratinization, except one. Which one is this exception?

a. Attached gingiva

b. Sulcular epithelium

c. Alveolar mucosa

d. Soft palate

a. attached gingiva

CASE C

29. Which of the following is not a component of the periodontium?

a. Gingiva

b. Crown

c. Periodontal ligament

d. Alveolar bone

b. crown

CASE C

30. Which of the following is not a histological component of the gingival connective tissue?

a. Enamel

b. Lymphatic tissues

c. Collagen fibers

d. Blood cells

a. enamel

CASE C

31. Which tissue surrounds the tooth and creates a cuff of gingiva extending coronally approximately 1.5 mm from the CEJ?

a. Periodontal ligament

b. Free gingiva

c. Attached gingiva

d. Oral mucosa

b. free gingiva

CASE C

32. What are the clinical observations noted during an examination of the gingiva indicating gingival health?

a. Loosely attached gingiva

b. Firm attached gingiva

c. Purple-colored gingiva

d. Inflamed gingiva

b. firm attached gingiva

CASE C

33. What relationship does tooth size have on the interdental papilla?

a. The smaller the tooth the larger the papilla

b. The larger the tooth the smaller the papilla

c. The larger the tooth the larger the papilla

d. Tooth size does not relate to papilla size

d. tooth size does not relate to papilla size

CASE C

34. The inner and outer surfaces of alveolar bone are made up of ________________.

a. Spongy bone

b. Cortical plates

c. Cementum

d. Oblique fibers

b. cortical plates

CASE C

35. The wall of the tooth socket is lined by what type of bone?

a. Trabecular

b. Dentin

c. Lamina Dura

d. Cancellous

c. lamina dura

CASE C

36. The tooth is attached to the underlying bone through which of the following?

a. Periodontal fibers

b. Attached gingiva

c. Cementum

d. Interradicular bone

a. periodontal fibers

CASE C

37. Which tooth appears in the permanent dentition but not in the primary?

a. Molars

b. Lateral Incisors

c. Central Incisors

d. Premolars

d. premolars

CASE C

38. Which one of the tooth components has an equivalent hardness to bone?

a. Cementum

b. Enamel

c. Dentin

d. Dentin Tubules

b. enamel

CASE D (39-50)

age: 76

gender: male

weight: 200lbs

vitals: 130/85 bp, 80 pulse, 14 respirations

social history: enjoying retired life

cc: maintain oral health

med: statin, NSAIDS, inhaler

medical history: elevated cholesterol, osteoarthritis in back, asthma, sleep apnea

dental history: spradic recall visits

gingival: generalized recession w exposed cementum

dentition: mod restorative restorations

radiographs: generalized horizontal bone loss

deposits: moderate subginigval interproximal deposits

perio charting: bop, mucogingival defects in lower molars, pocket depths ranfing from 4-7mm

CASE D

39. What attachment mechanism attaches the cells in the basal layer of stratified squamous epithelium?

a. Desmosome

b. Hemidesmosome

c. Gap

d. Tight

a. desmosome

CASE D

40. Which of the following are characteristics of bundle bone?

a. Covered by endosteum

b. Adjacent to periodontal ligament and adjacent to fatty marrow

c. Adjacent to fatty marrow and covered by endosteum

d. Contains Sharpey’s fibers and is adjacent to periodontal ligament

d. contains sharpey’s fibers and is adjacent to periodontal ligament

CASE D

41. What type of cells are found in Howship’s lacunae?

a. Osteocytes

b. Osteoclasts

c. Cementocytes

d. Cementoblasts

b. osteoclasts

Howship’s lacunae are found in areas of resorbed bone. The bone-resorbing cells (osteoclasts) are found in these hollowed out depression that the osteoclasts created

CASE D

42. What is the name of the space occupied by the body of the cementocyte?

a. Lamellae

b. Lacuna

c. Canaliculi

d. Cementicle

b. lacuna

CASE D

43. Cementum differs from bone in that cementum:

a. Contains cells

b. Has no blood vessels

c. Is 50% inorganic and 50%organic

d. Resorbs more readily

b. has no blood vessels

CASE D

44. What is the name for the outer, less-calcified layer of cementum?

a. Cellular cementum

b. Acellular cementum

c. Cementoid

d. Cementicles

c. cementoid

CASE D

45. What name is given to the remnants of Hertwig’s epithelial root sheath found in the periodontal ligament of a functioning tooth?

a. Enamel pearls

b. Denticles

c. Rests of Malassez

d. Cementicles

c. rests of malassez

these are the source of cyst formation

CASE D

46. The crystalline formation of mature bone consists of mainly which of the following?

a. Calcium hydroxyapatite

b. Osteoid

c. Osteocytes

d. Canaliculi

a. calcium hydroxyapatite

CASE D

47. What tissue component of the periodontal ligament is responsible for the production of the fibrous matrix and ground substance?

a. Osteoblast

b. Cementoblast

c. Odontoblast

d. Fibroblast

d. fibroblast

CASE D

48. Which portion of the tooth germ is the primary source of the periodontal ligament?

a. Dental follicle

b. Herwig’s epithelial root sheath

c. Stratum intermedium

d. Central cells of dental papilla

a. dental follicle

this is the tooth germ and three embryological structures the enamel organ, dental papilla, and dental sac

CASE D

49. The upper deep cervical nodes primarily drain all except:

a. Tonsils

b. Base of the tongue

c. Third molars

d. Soft palate

d. soft palate

it is drained by the retropharyngeal nodes

CASE D

50. Pulp changes result from aging. Changes result from:

a. Increased collagen fibers

b. True denticles

c. False denticles

d. Diffuse calcification

a. increased collagen fibers