DDS Dental Anatomy and Histology 1 — Questions and Answers
Question 1: Which layer of enamel is formed first during tooth development?
- Inner enamel layer (Correct answer)
- Outer enamel layer
- Dentinoenamel junction layer
- Striae of Retzius
Correct answer: Inner enamel layer
The inner enamel layer adjacent to the dentinoenamel junction is formed first as ameloblasts begin secreting enamel from that interface outward.
Question 2: What is the primary organic component of mature enamel?
- Amelogenin
- Enamelin (Correct answer)
- Tuftelin
- Ameloblastin
Correct answer: Enamelin
Enamelin constitutes the main organic protein retained in fully mature enamel, whereas amelogenin is largely removed during maturation.
Question 3: The Tome's process is an extension of which cell?
- Odontoblast
- Ameloblast (Correct answer)
- Fibroblast
- Cementoblast
Correct answer: Ameloblast
Tome's process is the apical cytoplasmic extension of the ameloblast that secretes enamel matrix and determines prism orientation.
Question 4: Which type of dentin is produced throughout the life of the tooth in response to normal physiologic stimuli?
- Primary dentin
- Secondary dentin (Correct answer)
- Tertiary dentin
- Sclerotic dentin
Correct answer: Secondary dentin
Secondary dentin is deposited by odontoblasts after root formation is complete and continues slowly throughout the tooth's functional life.
Question 5: The perikymata visible on the crown surface of a tooth correspond to which histologic structure?
- Hunter-Schreger bands
- Striae of Retzius (Correct answer)
- Enamel tufts
- Enamel spindles
Correct answer: Striae of Retzius
Perikymata are the external surface manifestations of the striae of Retzius, representing incremental growth lines in enamel.
Question 6: Which root cementum type contains entrapped cementoblasts within its matrix?
- Acellular afibrillar cementum
- Acellular extrinsic fiber cementum
- Cellular intrinsic fiber cementum (Correct answer)
- Cellular mixed stratified cementum
Correct answer: Cellular intrinsic fiber cementum
Cellular intrinsic fiber cementum contains cementocytes trapped in lacunae, similar to how osteocytes are trapped in bone.
DDS Dental Anatomy and Histology 1
Which layer of enamel is formed first during tooth development?