Morphologic, Structural, and Chemical Properties of Pulp Stones in Extracted Human Teeth

Pulp stones are mineral structures that develop in the pulp tissue triggered by several clinical conditions. The exact biochemical process behind the occurrence of pulp stones is uncertain. This study aimed to perform a structural and crystallographic characterization of pulp stones and dentin from extracted human teeth. The sample consisted of 13 erupted and unerupted permanent human teeth diagnosed with pulp stones. The teeth were analyzed with scanning electron microscopy with secondary and backscattered electrons, energy-dispersive spectroscopy, micro-Raman spectroscopy, micro–X-ray diffraction, and inductively coupled plasma atomic emission spectroscopy. The pulp stones revealed a heterogeneous morphology and structure compared with each other. Compared with the adjacent dentin, the pulp stones had a similar structure. From a chemical point of view, oxygen, calcium, carbon, and phosphorus were the most prevalent chemical elements in the inner part of the stones, whereas on the surface carbon, nitrogen, sulfur, chlorine, aluminum, potassium, zinc, copper, and lead were the most prevalent. Copper, iron, and zinc were higher in the stones than the dentin (P < .05). Statistically significant differences between the chemical structure of stones from erupted and unerupted teeth were not detected (P > .05). Pulp stones have structural and chemical properties that are similar to dentin. Variations in morphology are common.