A study of the mineral phase of pulp calcification

The Pulp Stones: Morphological Analysis in Scanning Electron Microscopy and Spectroscopic Chemical Quantification

Background and objectives: Pulp stones are hard tissue structures formed in the pulp of permanent and deciduous teeth. Few studies have evaluated their morphology and chemical composition. However, their formation, composition, configuration and role played in overall health status are still unclear. Clinically, they may be symptomatic; technically, they impede access during endodontic therapy, increasing the risk of treatment errors. Thus, this study aimed to morphologically analyze pulp stones and present their chemical quantification, identifying their main chemical elements. It also correlates the results with their possible induction mechanisms. Materials and Methods: Seven pulp nodules were collected from molar teeth needing endodontic treatment. The morphology of the stones was analyzed by scanning electron microscopy (SEM), and their chemical composition was determined by X-ray dispersive energy spectroscopy (EDX). Results: These structures varied considerably in shape, size and topography. The site of the stones in the pulp cavity was the factor that most affected the morphology. The majority of the stones found in the pulp chambers presented nodular morphology, while those in the root canals presented a diffuse shape, resembling root canal anatomy. The topography of the nodules showed heterogeneous relief, revealing smooth and compact areas contrasting with the rugged and porous ones. The chemical composition varied depending on the location of the nodule in the pulp cavity and the relief of the analyzed area. Radicular stones presented considerably lower calcium and phosphorus content than coronary nodules. Conclusions: The high cellularity rate of the coronal pulp predisposes this region to nodular mineralizations around injured cells. The presence of larger caliber vascular bundles and higher collagen fiber content in radicular pulp determines a diffuse morphological pattern in this region. Understanding the morphology and chemical composition of the pulp stones allows future translational pathways towards the prevention or treatment of such conditions.

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

INTRODUCTION

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.

METHODS

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.

RESULTS

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).

CONCLUSIONS

Pulp stones have structural and chemical properties that are similar to dentin. Variations in morphology are common.

Correlation between Pulp Stones and Gall Bladder Stones: A Radiographic Retrospective Case-Control Study

Background

Calcifications can occur in the dental pulp as discrete bodies known as pulp stones. Their etiology remains obscure. They were believed to be formed as a result of local irritating factors within the pulp; however, a few authors now suggest that they may be a part of systemic biomineralization process that affects many body parts such as kidneys, gall bladder, joints, arteries as well as pulp leading to formation of stones.

Aim

This retrospective case-control study was taken up to (i) determine the prevalence of pulp stones as well as pulp chamber narrowing in patients with gallbladder stones as well as the controls (ii) whether any correlation exists between the prevalence of pulp stones and gallbladder stones so as to test the hypothesis that pulp stones and gallbladder stones may be a part of a common systemic calcification process.

Setting and Design

This retrospective case-control study was conducted in the Department of Gastroenterology and Department of Radiodiagnosis, Sri Guru Ram Das Institute of Medical Sciences and Research, Amritsar. A total of 200 individuals were taken up for the study. Group I consisted of 100 patients (cases) with confirmed diagnosis of gallbladder stones. Group II included the control group in which individuals who were the close relatives of the patients with gall bladder stones were taken (n = 100), so as to eliminate the common confounding factors in these two groups such as diet, air, water, environment, genes, and age, which could affect the formation of pulp stones could not be the reason for the formation of pulp stones.

Materials and Methods

Standard bitewing radiographs were taken for all the patients in each group and presence or absence of pulp chamber narrowing and pulp stones were observed.

Statistical Analysis Used

McNemar's statistical test was used to find the difference between the two groups, and the P value was determined. Coefficient of association using the Phi coefficient was used to determine if there was any association between the two groups.

Results

In Group I, 37% of the patients with gallbladder stones showed the presence of pulp stones; whereas in the Group II which was the control, 57% of individuals showed the presence of pulp stones. McNemar's test of significance calculated with one-degree freedom (1-df) showed that P = 0.01, thereby showing that there was a significant difference between these two groups.

Conclusion

According to the study, a negative correlation between pulp stones and gallbladder stones was found and they are not related to each other.

Pulp biology: progress during the past 25 years

During the past 25 years there has been a rapid expansion in our knowledge of the dentine and pulp complex. This paper provides representative examples of important advances that researchers have made in this field. Topics to be considered include: differentiation of odontoblasts, dentine matrix proteins, extent of odontoblast processes, pulpal stem cells, apoptosis, interstitial fluid pressure in normal and inflamed pulps, class II antigen-presenting cells of the pulp, cytokines, antibodies, pulpal calcifications, tertiary dentine and pulpal inflammation associated with bacterial contamination of exposed dentine beneath restorations.

Unusual case of general pulp calcification (pulp stones) in a young Greek girl

An unusual case of generalized pulp calcification is reported in a 14-year-old Greek girl. Radiographic examination revealed large pulp stones in all permanent teeth located in the pulp chamber and sometimes extending to the coronal portion of the root canal. The patient's dental, medical and family history, as well as the findings from the clinical examination were non-contributory. Biochemical analysis of one pulp stone removed from the right maxillary central incisor revealed large amounts of urates, proteins and phospholipids, but a blood test of the patient showed no metabolic disturbance. Therefore, it is suggested that this unusual case may be of idiopathic origin.

Brushite in the pulp of primary molars

This study was undertaken to investigate the mineral phase of spherulitic calcifications discovered in the pulpous mesenchyme of human primary molars by microradiography. Analytical scanning electron microscopy and x-ray diffraction disclosed that well-crystallized brushite is the major compound of the spherulites. The mechanism leading to the crystallization of brushite is far from well understood. Histologically, on decalcified sections, inflammatory cells and capillaries can be seen trapped in the spherulites. In the light of these findings, it could be suggested that metabolic conditions may promote the crystallization of brushite in the pulp of primary molars.

Transmission electron microscopy of the morphological relationship between fibroblasts and pulp calcifications in temporary teeth

Calcifications found in the coronal pulps of primary teeth extracted in an 8-year-old child were studied by TEM. Different types of relationship were observed between fibroblasts and pulp calcifications: extension of cell processes towards calcifications, modelling of the cells upon calcifications, internalizing process of calcifications. Fibroblasts proved to be able to enclose small pulp calcifications within intracytoplasmic vesicles. There was no evidence of any active role played by fibroblasts in the genesis of pulp calcifications. It was shown that collagen fibres could be involved or not in the mineralizing process. It is suggested that mitochondria might provide an adequate environment for initial mineralization. It is likely that the role played by the cytoskeleton in the internalizing process of calcifications is important.