Evaluating the Concentration of MMP-9 and TNF- α in Pulpal Blood at Various Stages of Pulpal Inflammation in Diabetics: A Cross Sectional Study.

Objective: To investigate the concentration of Matrix metalloproteinases-9 (MMP-9) and Tumor necroses fac- tor-alpha (TNF- α) in pulpal blood at various stages of pulpal inflammation in diabetics and to establish the relationship between these two biomarkers.

Methods: 77 patients, each having a tooth with pulpal exposure due to caries presenting with distinct stages of pulpitis were grouped into 2 main study groups as based on the HbA1c Levels-Group 1: Non-Diabetics (Control Group) (HbA1c < 5.6%) and Group 2: Type 2 Diabetics (Experimental Group) (HbA1c>6.5%; Random Plasma Glucose > 200) and diabetes mellitus with less than 10-year history. Depending on the radiological and clinical diagnosis, these two groups were again sub-divided into 2 subgroups: Sub-group A: Tooth with Symptomatic Irreversible Pulpitis. Sub Group B: Tooth with Reversible Pulpitis. Thus, for comparison purposes, a total of 4 sub-divisions were formed: Sub-group 1A- Non-Diabetic, Symtomatic Irreversible Pulpitis, Sub- group 1B: Non-Diabetic, Reversible Pulpitis, Sub-group 2A: Diabetic, Symptomatic Irreversible Pulpitis, Sub- group 2B: Diabetic, Reversible Pulpitis. Blood sample was collected from pulp chamber after partial pulpo- tomy was done. The total levels of MMP-9 and TNF-α were assessed by enzyme linked immunosorbent assays (ELISA). Inter-group comparison in levels of MMP-9 and TNF- α were conducted using the Kruskal Wallis test and pairwise comparison was done Mann-Whitney U test.

Results: The inter-group comparison in levels of MMP-9 and TNF- α were conducted using the Kruskal Wallis test and pairwise comparison was done using Mann-Whitney U test. Pearson correlations were conducted in order to investigate correlations between the paired TNF-α and MMP-9 values and also their correlation with the blood sugar levels within the pulp diagnosis groups. MMP-9 and TNF-α levels were significantly higher (p<0.005) in irreversible pulpits than reversible pulpits and also in Type-2 diabetics than non-diabetics. High- est level of MMP-9 and TNF-α was found in Group 2A (Diabetic, symptomaticirreversible pulpitis) and lowest in Group 1B (Non-Diabetic, reversible pulpitis). There exists a very high significant positive correlation between MMP-9 and TNF-α (p<0.005).

Conclusion: These findings show that the inflammatory mediators MMP-9 and TNF-α are significantly in- creased in pulpal blood samples of diabetic patients. Also, in diabetic patients diagnosed with reversible pul- pitis, higher levels of inflammatory pulpal biomarkers were reported that could compromise the success of Vital Pulp Therapy (VPT) and may necessitate endodontic intervention. MMP-9 and TNF- α were reported to have a positive correlation. (EEJ-2023-01-04).