Secondary and Tertiary Dentin
Secondary dentin is that which is deposited in the pulp structures. This process occurs after the primary dentin has fully formed, usually as part of aging.9 Dentinal deposition can be a response to a variety of conditions such as moderate carious lesions, prolonged tooth trauma, deep restorative treatments, and tooth-wearing processes like attrition (Figure 52), abrasion, and erosion.7,9 In such instances, the term tertiary dentin may be applied, suggesting that the additional dentin is deposited in response to conditions unrelated to aging.7,9
Age-related secondary dentin deposition diminishes the size of the pulp chamber, especially the pulp horns early in the process, and the pulp canals.9 These changes can be visualized radiographically. This process may eventually result in obliteration of all pulp structures.7,9 Tertiary dentinal deposition tends to be a more rapid, localized process by comparison.7
Periapical radiographs showing secondary dentin deposition likely due to attrition.
Several other types of calcifications can affect the pulpal structures of the teeth including pulp stones and pulpal sclerosis. The stones tend to be more localized while pulpal sclerosis is more generalized.
Pulp stones are small focal calcifications that occur within the pulp structures of the teeth. Of unknown origin, pulp stones are rather common and affect the teeth of both the young and old.9 Most stones are so tiny that they cannot be seen radiographically, while others are large and calcified enough to be visualized.7Their size, shape, number, and density are variable, and they can be found in every type of tooth, but especially the molars (Figure 53).9 No treatment is required.
Bitewing and periapical radiographs showing posterior pulp stones of varying sizes.
Another alteration of the pulp structures, sclerotic changes can result in complete obliteration of the pulp chamber and canals (Figures 54‑55). Although the etiology is unknown, total obliteration may be a result of trauma to the affected tooth.7 The calcifications are diffuse and ill-defined radiographically, with a strong association with older age.9 This process is asymptomatic and requires no treatment. If endodontic therapy is indicated, the calcification may present difficulty in completing the procedure.9
Periapical radiograph of pulpal sclerosis with total obliteration of pulp structures #30.
Periapical radiograph of pulpal sclerosis in the mandibular anterior teeth