Evaluation of Vitamin D and of Some Biomarkers of Bone Remodelling (CTX-1, Osteocalcin, BALP) in Subjects with Periapical Inflammatory Cysts: An Observational Study

<b>Objectives:</b> The aim of this observational study was to evaluate whether the presence of periapical inflammatory cysts (PIC) is accompanied by a state of vitamin D (25OHD) 25(OH)D insufficiency or deficiency and biochemical variations in biomarkers of bone metabolism such as osteocalcin (OC), isoenzyme of bone alkaline phosphatase (BALP), and C-terminal telopeptide of type 1 collagen (CTX). <b>Methods:</b> A total of 56 patients (group P), 36 males and 20 females, of which 42 had one cyst (group P1) and 14 had multiple periapical cysts (group P2), alongside 56 healthy subjects (group H) were recruited. Rx-OPT and clinical evaluation were used to evaluate the presence of PIC. At the first visit, all subjects underwent venous sampling (group P and H) to measure bone biomarkers by the chemiluminescence method. The Mann-Whitney test was used to compare the different biomarkers in the H vs. P, H vs. P1, H vs. P2, and P1 vs. P2 groups. The Mann-Whitney test was used to compare biomarker levels between the study groups. ROC curves were used to search for the concentration of the different biomarkers in which the best sensitivity and specificity were found. <b>Results:</b> 25OHD and CTX showed a difference between H vs. P, H vs. P1, H vs. P2, and P1 vs. P1 groups (<i>p</i> < 0.05). The study of the ROC curves with a comparison between concentrations in the H vs. P group showed the best sensitivity and specificity for 25OHD at a concentration <19 ng/mL, highlighting a picture of 25OHD deficiency. <b>Conclusions:</b> The presence of apical cysts could be indicative of a vitamin D deficiency that should be appropriately treated. The findings suggest that vitamin D deficiency, given its role in bone metabolism and mineralisation, may contribute to a biological environment that favours the development or persistence of periapical cystic lesions.