Characterization of inflammatory cell infiltrate in human dental pulpitis.

INTRODUCTION: To evaluate the microscopic characteristics and densities (per mm(2) ) of tryptase(+) mast cells, CD4(+) T helper lymphocytes, CD45RO(+) memory T lymphocytes, foxp3(+) T regulatory lymphocytes, CD20(+) B lymphocytes, CD68(+) macrophages, and CD31(+) blood vessels in human dental pulpitis (n=38) and healthy pulpal tissue (n=6). METHODOLOGY: The pulps of 38 human teeth with a clinical diagnosis of irreversible pulpitis were removed by pulpectomy. The pulp tissue was immersed in 10% buffered formalin for evaluation using light microscopy. Tryptase, CD4, CD45RO, foxp3, CD20, CD68, and CD31 expressions were analysed using immunohistochemistry; other microscopic features, such as intensity of inflammatory infiltrate and collagen deposition, were evaluated using haematoxylin and eosin stain. Wilcoxon and Mann-Whitney tests were used for statistical analysis. The significance level was set at α=5%. RESULTS: Two microscopic patterns of pulpitis were found: group 1 (G1) (n=15) had an intense inflammatory infiltrate and mild collagen deposition; conversely, group 2 (G2) (n=23) had a scarce inflammatory infiltrate and intense collagen deposition. The numbers of CD68(+) macrophages (P=0.004) and CD20(+) B (P=0.068) lymphocytes and the density of blood vessels (P=0.002) were higher in G1 than in G2. However, a similar number of CD4(+) and CD45RO(+) T lymphocytes was found in both groups (P>0.05). When present, tryptase(+) mast cells were equally distributed in G1 and G2, whereas foxp3(+) T regulatory lymphocytes were detected in 59% and 14% of the samples of G1 and G2. Controls exhibited lower numbers of foxp3, tryptase, CD4, CD45RO, CD68 and CD20 positive cells than G1 and G2. CONCLUSIONS: Irreversible pulpitis had distinct microscopic features with important quantitative and qualitative differences in inflammatory cell infiltration.

Digital subtraction radiography evaluation of the bone repair process of chronic apical periodontitis after root canal treatment.

AIM: To monitor radiographically the progress of bone repair within chronic periapical lesions after root canal treatment using digital subtraction radiography (DSR). METHODOLOGY: Twelve patients with 17 single-rooted teeth with chronic apical periodontitis associated with an infected necrotic pulp were selected for root canal treatment. Periapical radiographs were taken before treatment (baseline) and immediately post-treatment, 45, 90, 135 and 180 days after treatment. The radiographic protocol included the use of individualized film holders with silicone bite blocks. The six radiographic images were digitized and submitted to digital subtraction using DSR software, resulting in five subtracted images (SI). Quantitative analysis of these SI was performed using Image Tool software to assess pixel value changes, considering a step-wedge as the gold standard and a cut-off value of 128 pixels. The aim was to identify any increase or decrease in mineral density in the region of the periapical lesion. RESULTS: A minor decrease in mineral density at the canal filling session and a significant progressive mineral gain in the following evaluations (P < 0.001) occurred. Pairwise comparison of pixel grey values revealed that only the 180-day follow-up differed significantly from the previous SI. CONCLUSION: Digital subtraction radiography is a useful method for evaluating the progress of bone repair after root canal treatment. Noticeable mineral gain was observed approximately 90 days after root canal filling and definite bone repair after 180 days.