## 4 Discussion
[20], using the ELISA method, revealed that MMP-1, MMP-8, and MMP-13 had statistically significant (\(p<0.01\)) increased levels in dental pulp with chronic inflammation versus the control group. Osteocalcin presented statistically significant augmented concentrations in the chronically inflamed pulp sample group compared to acute inflamed pulp tissues (\(p=0.002\)). In chronic inflammation, granulation tissue replaces the normal architecture of the dental pulp and proliferation of small vessels may take place [21]. Histologically, chronically inflamed dental pulp is characterized by a chronic inflammatory infiltrate consisting of lymphocytes, histiocytes, and plasmocytes, newly formed vessels (through angiogenesis), fibroblasts proliferation, and collagen, which results in a fibrous tissue. Osteocalcin was associated with the presence of markers of angiogenesis, and it was also localized in areas of fibrosis [8], which may explain the elevated levels in chronically inflamed pulp samples in our study. On the other hand, [PERSON] et al. [8] reported that osteocalcin may have an important role in chronic pulpitis without irreversible changes. More studies are needed to elucidate the actual mechanisms of osteoclastcin and other biomarkers in chronic pulpal inflammation. TNF-\(\alpha\) is produced by macrophages, as a response to dental infections, and may stimulate neutrophils to form high concentrations of ROI [6]. The present results are partially in agreement with the results by [PERSON] et al. [22], who, by using the same method of testing, found statistically significant elevated levels of TNF-\(\alpha\) in irreversible asymptomatic and symptomatic pulpitis samples (\(p=0.000\)), but they also reported SS differences between the samples of irreversible symptomatic and asymptomatic pulp samples (\(p=0.000\)), without mentioning the origin of pulp tissue (primary/permanent teeth). Other studies with similar results, but realized on pulp samples from permanent teeth, include those by [PERSON] et al. [8], with statistically significant higher levels (\(p<0.01\)) in irreversibly inflamed pulp tissues, which were clinically sensitive to hot stimuli with spontaneous lingering pain; [PERSON] et al. [23], with higher concentrations in irreversibly inflamed symptomatic pulpitis samples compared to the control group (\(p<0.05\)); [PERSON] et al. [24], with statistically significant elevated levels (\(p=0.015\)) in irreversible pulpitis samples extracted from teeth with prolonged or spontaneous pain versus the control group; and [PERSON] et al. [25], with statistically significant elevated levels in pulp samples obtained from teeth with acute pulp inflammation (\(p=0.05\)). Even though [PERSON] et al. [23] utilized pulpal blood for protein determination, [PERSON] et al. [25] and [PERSON] et al. [24] investigated TNF-\(\alpha\) gene expression using RT-PCR; the inflamed pulp samples expressed increased levels of TNF-\(\alpha\) versus normal pulp tissues. We found a single paper [26], without mentioning if samples were collected from primary/permanent teeth, where the authors reported the study groups as \"normal pulp tissue\", \"acute pulitis\", and \"chronic pulpitis\", with SS differences between normal and acute and chronic pulpitis specimens (\(p<0.01\)). The results were comparable to the ones in our research; however, statistically significant differences between the acute and chronic pulpitis group (\(p<0.05\)) were also reported, in contrast with our results. In our study, statistically significant elevated levels of SOD-3 (\(p<0.001\)) were observed in both acute and chronically inflamed pulp samples, compared to healthy pulp specimens. ROIs are produced in physiological and pathological conditions, but their concentrations differ in each situation. In healthy tissues, ROIs are produced in small quantities, but elevated levels of ROI, produced by macrophages, may cause excessive tissue damage and lipid peroxidation, protein oxidation, and nucleic acid damage [27].