Quantitative Analysis of Lactobacillus and Enterococcus faecalis between Irreversible Pulpitis and Pulp Necrosis in Primary Teeth

Introduction: Root canal infection is a common consequence of dental caries which can cause premature loss in primary dentition. The exposure of pulp tissue to the oral environment allow oral microorganisms to access into the pulp chamber and lead to pulp necrosis without treatment. To identify bacteria associated with root canal infection would be beneficial and lead to providing more effective treatment. Aims: To quantify Lactobacilli and Enterococcus faecalis levels in infectious root canal of primary teeth between irreversible pulpitis and pulp necrosis groups, and to analyze the association between these bacteria and clinical signs and symptoms. Materials and methods: Total subjects were 170 Thai children aged 2-10 years old. All subjects were selected from patients who came to the pediatric dental clinic, Pediatric Department, Faculty of Dentistry, Mahidol University, Thailand and needed a pulpectomy treatment. DNA extraction and quantitative real-time PCR was performed. Results: Mean age of the children was 5 ± 1.3 years old. One hundred and ten samples were diagnosed with irreversible pulpitis and 60 with pulp necrosis. One hundred and seven subjects (63%) had a history of pain. One hundred and twenty subjects (71%) had clinical signs and symptoms. One hundred and thirty-four radiographs (79%) showed radiographic pathology. The detection of total bacteria, Lactobacillus and E. faecalis was 100%, 100% and 84% (142/170), respectively. The ratio of Lactobacillus and E. faecalis to total bacteria levels was 20% and 9%, respectively. When compared between irreversible pulpitis and pulp necrosis groups, the quantities of total bacteria (p=0.000), Lactobacillus (p=0.000) and E. faecalis (p=0.001) in pulp necrosis group were higher than those of the irreversible pulpitis group. The ratio of Lactobacillus to total bacteria in the pulp necrosis group was higher than in the irreversible pulpitis group (p=0.004), whereas the ratio of E. faecalis to total bacteria was not different between the two groups. Only Lactobacillus was associated with a history of pain (p=0.013). Gingival swelling was correlated with Lactobacillus quantities (p=0.01). When analyzed within each group, E. faecalis quantity was correlated with clinical pain (p=0.01) in pulp necrosis group. In the irreversible pulpitis group, the data showed pathologic finding of lamina dura (p=0.000) and furcation involvement (p=0.016) which correlated with E. faecalis quantities. Conclusion: The bacterial levels of total bacteria, Lactobacillus and E. faecalis in pulp necrosis group were higher than the irreversible pulpitis group. Levels of Lactobacillus and E. faecalis were associated with a history of pain, pathologic finding of lamina dura and furcation involvement. Gingival swelling was correlated with Lactobacillus quantities.