Background Matrix metalloproteinases (MMPs) are critical enzymes involved in the remodeling and defense mechanisms of dental pulp tissue. While their role in permanent teeth has been extensively studied, research focusing on MMPs in primary teeth remains limited. This gap highlights the need for further investigations to understand the specific contributions of MMPs to pulpal defense in primary teeth. Moreover, the clinical efficacy of Biodentine as a pulpotomy material in primary teeth warrants further exploration through well-designed studies to establish its success and long-term outcomes in pediatric dentistry. Aim This study aims to compare the expression levels of MMP-2, MMP-8, and MMP-9 in cases of reversible and irreversible pulpitis. Additionally, it seeks to evaluate the clinical success of Mineral Trioxide Aggregate (MTA) and Biodentine when used as pulpotomy agents in primary molars. By analyzing the differential expression of these MMPs, the study will contribute to a better understanding of their role in pulpal inflammation and the potential therapeutic outcomes of MTA and Biodentine in primary molars. Design In this parallel randomized controlled trial, 63 mandibular primary second molars were assigned to two main groups: Group 1, consisting of 42 teeth diagnosed with reversible pulpitis, and Group 2, consisting of 21 teeth diagnosed with irreversible pulpitis. Group 1 was further divided into two randomized subgroups, each containing 21 teeth. The expression levels of MMP-2, MMP-8, and MMP-9 were evaluated in all samples. Pulpotomy treatments were performed using MTA and Biodentine in Group 1. Clinical and radiographic evaluations were conducted over an 18-month follow-up period. Statistical analyses were carried out using The Kolmogorov-Smirnov test, t-test and Fisher's exact test (p < 0.05). Results The study revealed that MMP-2 and MMP-9 expression levels were significantly elevated in specimens with irreversible pulpitis (p = 0.01), indicating a potential correlation between these matrix metalloproteinases and the severity of pulpal inflammation. However, no significant difference was observed in the clinical success rates of pulpotomies performed with MTA and Biodentine, suggesting that both materials are equally effective in the treatment of primary molars with reversible pulpitis. Conclusions The expression of MMP-2 and MMP-9 in pulpal blood presents a promising biomarker for assessing the degree of pulpal inflammation in primary teeth, offering a potentially valuable diagnostic tool. Additionally, the clinical success of Biodentine in pulpotomy procedures supports its viability as an effective alternative to MTA, providing a reliable option. Clinical Trial Registration ID The study protocol has been registered with an ID: NCT05145686. Registration Date: 9th November 2021.
