National Board Dental Hygiene Examination (NBDHE) Dental Hygienist Practice Test

Hypersensitivity of a root lessens as the tooth forms which of the following?

1. Periodontal Ligament

2. Pulp

3. Cellular cementum

4. Enamel

The correct answer is: Cellular cementum

The correct choice relates to the role of cellular cementum in the context of tooth development and hypersensitivity. As a tooth forms, particularly during the eruption process, the development of cellular cementum plays a critical role in covering the root surface. This formation helps to provide a protective layer over the dentin that could be exposed and potentially sensitive. As cellular cementum is deposited, it effectively seals the dentinal tubules that might otherwise be exposed to external stimuli. This sealing action reduces the permeability of the dentin and helps diminish hypersensitivity by buffering the effects of cold, hot, or sweet stimuli on the dentinal nerve endings. Consequently, as more cellular cementum is formed, it lessens sensitivity in the root area. The other options, such as periodontal ligament, pulp, and enamel, do not directly contribute to reducing root hypersensitivity in the same way that cellular cementum does. The periodontal ligament provides support and anchors the tooth but doesn't seal the root surface. The pulp is involved in tooth vitality and sensory functions but does not directly affect hypersensitivity related to root exposure. Enamel, while crucial for tooth protection, primarily covers the crown of the tooth and does not play a role in root hypersensitivity. Therefore, cellular cementum is the