Dental Anatomy and Histology Flashcards

Which permanent tooth has the longest root in the human dentition?

Answer: Upper canine

The maxillary canine has the longest root of any tooth in the human dentition. Its long, robust root provides excellent anchorage, which is why canines are often the last teeth to be lost in the ageing dentition and serve as important abutments in prosthodontics.

What is the Tome's process associated with?

Answer: Ameloblasts secreting enamel matrix

Tome's process is a cytoplasmic extension of the ameloblast cell that is responsible for secreting the enamel matrix during the secretory stage of amelogenesis. The shape and orientation of Tome's processes determine the characteristic rod and inter-rod pattern of mature enamel.

How many root canals does a mandibular first molar typically have?

Answer: Three

The mandibular first molar typically has two roots (mesial and distal) with three root canals — two in the mesial root (mesiobuccal and mesiolingual) and one in the distal root. However, a second distal canal is found in approximately 30% of cases, making four canals common.

Which type of dentine is formed as a physiological response throughout life?

Answer: Secondary dentine

Secondary dentine is deposited slowly and continuously by odontoblasts throughout the life of a vital tooth, after root formation is complete. This gradually reduces the size of the pulp chamber. Tertiary dentine, by contrast, is formed as a pathological response to stimuli such as caries or attrition.

The Hunter-Schreger bands seen in enamel are caused by which structural feature?

Answer: Changes in direction of enamel rod groups

Hunter-Schreger bands are alternating light and dark bands seen in enamel under reflected light. They are caused by changes in direction (decussation) of groups of enamel rods, which creates zones that reflect light differently. This arrangement increases enamel's resistance to crack propagation.

Which tooth is most commonly congenitally absent (excluding third molars)?

Answer: Lower second premolar

The lower second premolar is the most commonly congenitally absent permanent tooth after the third molars. The upper lateral incisor is the second most commonly absent. Congenital absence (hypodontia) affects approximately 3–8% of the population for non-third-molar teeth.