Background: Dentin caries involves dissolution of minerals which eventually leads to degradation of organic matrix. This degradation which was thought to be by bacterial proteases is now considered to be orchestrated by endogenous collagenases such as Matrix Metalloproteinases (MMPs). This paper aims to estimate the salivary levels of MMP-8 in dental caries and also to asses the various risk factors that contribute to the formation of dental caries.

Material and methods: A random sample of 75 adults aged 18-35 were included and categorized based on the number of caries lesions (MCL). Standard clinical examinations were performed, and stimulated saliva was collected and analyzed for concentrations of MMP-8 using enzyme-linked immunosorbent assay. Caries risk factors were assessed using a chair-side kit. Correlation of MMP-8 in varying MCL using Spearman's correlation was done. Multiple linear regression analysis was done to asses the relationship between various caries risk factors with MMP-8 and MCL as dependent variable.

Results: The study results showed a statistically significant higher concentration of MMP-8 in carious group (MCL 1-2) and MCL ≥3 compared to non-carious group. On correlating, the levels of MMP-8 were seen to be higher in MCL ≥3 than in MCL = 0 and MCL 1-2. The mean MMP-8 of controls, MCL 1-2, and MCL ≥3 were 131.34ng/ml, 230.14ng/ml, and 391.91ng/ml respectively. Multiple linear regression analysis with MMP-8 as the dependent variable revealed caries, buffer capacity and S. mutans count as significant variables. Using MCL as the dependent variable the only significant variable was MMP-8 levels.

Conclusions: The study suggests that subjects with caries have elevated MMP-8 levels compared with subjects with no carious lesions. There is also a positive correlation between the number of carious lesions and MMP-8 levels suggesting that MMP-8 plays an important role in the degradation of dentin and causes progression of caries. Key words:Caries, Dentin, Enzyme-linked Immunosorbent Assay, MMP-8.