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 factor-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 pulpotomy 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. Highest 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 & TNF-α (p<0.005). CONCLUSION: These findings show that the inflammatory mediators MMP-9 and TNF-α are significantly increased in pulpal blood samples of diabetic patients. Also, in diabetic patients diagnosed with reversible pulpitis, 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.