INBDE (Integrated National Board Dental Examination) 2025 – 400 Free Practice Questions to Pass the Exam

Reactionary secondary dentin is a response to minor injuries or irritants, such as dental caries or abrasion. Primary dentin is formed before the completion of the root, and reparative dentin forms in response to more severe damage, such as trauma or cavity preparation. Secondary dentin can be formed by the odontoblasts in the pulp cavity, as a reactive process, to provide additional protection to the pulp against external stimuli. This process helps to maintain the pulp's vitality and protect it from further damage. Therefore, choice C is the most appropriate answer. Choices A, B, and D are all incorrect because they refer to either different types of dentin or the degree of damage that induces their formation. Therefore, option C, reactionary, is the best fit for the question.