Final answer:
It is true that dentinal tubules become occluded with age due to odontoblast cellular projections. This natural aging process helps protect the tooth's inner pulp similarly to protective mechanisms seen in bone development. The occlusion minimizes the risk of decay reaching the sensitive areas of the tooth.
Step-by-step explanation:
The statement that with age, dentinal tubules become occluded because of odontoblast cellular projections is true. As a person ages, these tubules, which are channels in the dentin layer of the tooth, can become blocked by deposits or by the growth of odontoblasts' extensions. This can reduce the risk of tooth decay since fewer bacteria and harmful substances can reach the inner pulp. The dentin is the layer beneath the enamel and is also vulnerable to decay, especially if the enamel layer is compromised by tooth decay, as described in Figure 24.7 showing how decay progresses into deeper layers of the tooth.
Deciduous teeth typically emerge during infancy, permanent teeth follow starting from around the age of six, and wisdom teeth generally come in during late adolescence to early adulthood. Each phase of tooth development involves changes in the dentinal structure and susceptibility to decay.
Dentinal Tubule Occlusion with Age
Occlusion of the dentinal tubules over time is part of the natural aging process of teeth and is a defense mechanism to protect the internal pulp. This process is similar to how in endochondral ossification, as the cartilage calcifies, nutrients cannot reach the chondrocytes, resulting in their death and the eventual formation of the medullary cavity, as indicated in the chapter summary review.