What component makes up the majority of primary dentin?

Primary dentin is the type of dentin that forms during the development of the tooth, before eruption. It is laid down by odontoblasts and constitutes the bulk of the tooth structure beneath the enamel and cementum. This dentin is responsible for the overall strength and structural integrity of the tooth.

The majority of dentin in a mature tooth is primary dentin, which is formed continuously during tooth development and is characterized by its uniform structure and composition. Because primary dentin forms before any significant wear or repair processes occur, it provides a foundational role in supporting the tooth as it comes into function within the oral cavity.

The other components listed do not constitute the majority of the tooth structure as primary dentin does. Secondary dentin forms later in life and contributes to the tooth’s ability to withstand wear but is not present in the same volume as primary dentin. Cementum is a calcified tissue covering the roots of teeth, while enamel is the hard outer layer covering the crown, neither of which surpasses the volume of primary dentin as a component of the entire tooth structure. Therefore, primary dentin being identified as the majority component is accurate and reflects its critical importance in dental anatomy.