Epithelial-Induced Intrapulpal Denticles in B6C3F1 Mice

Abstract

Multiple intrapulpal denticles were observed in maxillary incisors of control and treated B6C3F1 mice used in a chronic inhalation study. Histologically, the denticles originated from multiple small budlike projections emanating from the epithelial sheath, immediately adjacent to the pulp chamber. The denticles were round to ovoid in shape with a central cavity surrounded by tubular dentin. Immature denticles contained epithelial cells within the central cavity, whereas mature denticles were either devoid of cells or contained cell fragments. A layer of columnar odontoblasts surrounded the outer surface of each denticle. Denticles advanced in a coronal direction as the incisors grew. With continued incisor growth, some denticles impacted the tooth wall and were associated with defects in dentinogenesis , altered tooth shape, and microfractures. Some denticles became partly or entirely incorporated into the dentin of the tooth. Intrapulpal denticle formation may represent a previously unidenti ed alteration that could contribute to the developmen t of dental dysplasia in mice by interfering with normal tooth development and predisposing affected teeth to malformation and biomechanica l failure with fracture.

Practical pathology of aging mice

“…7 as examples of subclinical histologic disease, which likely contributes significantly to the decline in functional health of the affected mouse and may be under diagnosed. We and others (54) have noted dysplastic intrapulpal denticles in the incisors of older mice (Fig. 7A,B).…”

Mouse

“…As a result, the reported incidence of more subtle changes in the teeth of mice may be artificially lower than would occur if sections of teeth were routinely examined. Long & Herbert (2002) presented information on the occurrence of calcified bodies (denticles) within the dental pulp, which they considered could affect the normal growth pattern of the teeth and lead to malformations and malocclusion of mouse incisors.…”

Proceedings of the 2017 National Toxicology Program Satellite Symposium

“…The voting choices and results were denticle (0%), dentin matrix alteration (5%), odontoblast disorganization with disruption of predentin/dentin (29%), denticle and odontoblast disorganization with disruption of predentin/dentin (41%), all of the above (26%), and other (0%). The audience voted for the correct answer of denticle and odontoblast disorganization with disruption of predentin/dentin (Long and Herbert 2002; Weber 2007).…”

“…The audience voted for the correct answer of denticle and odontoblast disorganization with disruption of predentin/dentin (Long and Herbert, 2002; Weber, 2007). …”