Pulp stones are calcified masses that occur in the pulp, either in the apical or coronal portions.  They are classified according to their structure or location. According to their location, pulp stones can either be classed as free (completely surrounded by soft pulp tissue), embedded (surrounded by dentine tissue) or adherent (attached to pulp wall and are continuous with dentine but not fully enclosed). Depending on the structure of the pulp stones they are either true (dentine lined by odontoblasts), false (formed from degenerating cells that mineralise) or diffuse (more irregular in shape to false stones). The cause of pulp stones is little understood however it has been recorded that pulpal calcifications can occur due to: