Evaluation of Matrix Metalloproteinase-9 (MMP-9) in Dentine Pulp Complex of Normal and Carious Tooth by an Immunohistochemical Analysis- An Invitro Study

Abstract

Introduction: Dental caries is a multifactorial disease that requires a susceptible host as well as cariogenic bacteria and diet in order to develop. MMP-9 is a gelatinases that have the ability to break down denatured collagen and type IV collagen (the main structure of extracellular matrix). The inhibition of MMPs may represent a key piece of the troubleshooting during dentin adhesion, and resulting in long-lasting  hybrid layer.

Aim: To evaluate the possible role of Matrix Metalloproteinase-9 (MMP-9) in Dentine Pulp Complex during caries progression.

Objectives: To compare and evaluate the expression Matrix Metalloproteinase-9 (MMP-9) in  Dentine Pulp Complex of normal teeth and carious teeth.

Methodology: 12 control (normal teeth) and 12 study (carious extracted teeth) Samples are collected and fixed in neutral buffered formalin. Decalcification done using EDTA. Tissue processing done. Evaluated for hematoxylin and eosin staining then immunohistochemical analysis is done.

Result: Brown coloured precipitate observed in the dentino-pulpal area and the cells of the pulp were considered as positive for MMP-9. The intensity of the staining reaction and the number cells expressing the MMP-9 stain were considered for the scoring of expression of MMP-9 for the particular tooth. Mann whitney U test revealed that MMP-9 staining score were significantly higher in test group  compared to control group.

 Conclusion:  In our study we tested MMP-9 in dentine-pulp complex of  two groups one with carious dentine and other with non-carious dentine. The non-carious teeth showed less positivity while comparing with carious teeth, which is one of the indicator and additive for carious progression.