The dental pulp has a rich microvasculature and a dense innervation to maintain homoeostasis of the pulp microenvironment and to preserve the integrity of the pulpo-dentine complex. In a hostile oral environment, the dental pulp is equipped with its neurovascular and cellular mechanisms to face the challenges of bacteria, trauma and functions, despite its lack of collateral blood supply and its low-compliance microenvironment. Dentine sensitivity and inflammatory pain are the two mechanisms involved in pain arising from the dental pulp and they are mediated by different types of pulp nerve fibres with their own characteristics. Clinicians are often faced with patients who have toothaches that are elusive and evade accurate diagnosis. This review aims to help clinicians gain insights into the dynamic interaction of the pulp nerves, microvasculature and cells in the pulp microenvironment, and to offer clinicians valuable aids in understanding the mechanisms that cause and modulate pain arising from the dental pulp. Various connections are made between biological science and clinical scenarios in relation to diagnosis of painful pulp conditions.