CAMPANELLIProgrammed Death 1 (PD-1) and PD-1 Ligand (PD-L1) Expression in Chronic Apical Periodontitis.

OBJECTIVE: This study aimed to examine programmed death protein 1 (PD-1) and programmed death lig-and 1 (PD-L1) expression on leukocytes from chronic apical periodontitis, and to determine the levels of cytokines in the apical periodontitis lesions. METHODS: Leukocytes from healthy gingival tissue (n=16) and chronic apical periodontitis (n=10) were eval-uated using flow cytometry. The PD-1 and PDL-1 expressions were evaluated using flow cytometry. The cy-tokine levels were evaluated by enzyme-linked immunosorbent assay. Data were analyzed using one-way ANOVA. The statistical significance level was set at P<0.05. RESULTS: Results showed that the apical periodontitis lesions are more infiltrated by PD-1+ and PDL1+ lym-phocytes than the control samples. In addition, the PDL-1 expression was detected on macrophages in the apical periodontitis lesions, and was significantly higher compared to leukocytes from healthy gingival tis-sue. The IFN-γ, TGF-ß, IL-10, and TNF-α levels were significantly higher in the apical periodontitis lesions com-pared to control samples. CONCLUSION: The PD-1, PD-L1, and CTLA-4 molecules are evident in apical periodontitis, and can be an impor-tant immune checkpoint in chronic periapical periodontitis.

Antimicrobial activity of calcium hydroxide and chlorhexidine on intratubular Candida albicans.

This study investigated the efficacy of calcium hydroxide and chlorhexidine gel for the elimination of intratubular Candida albicans (C. albicans). Human single-rooted teeth contaminated with C. albicans were treated with calcium hydroxide, 2% chlorhexidine gel, calcium hydroxide plus 2% chlorhexidine gel, or saline (0.9% sodium chloride) as a positive control. The samples obtained at depths of 0-100 and 100-200 µm from the root canal system were analyzed for C. albicans load by counting the number of colony forming units and for the percentage of viable C. albicans using fluorescence microscopy. First, the antimicrobial activity of calcium hydroxide and the 2% chlorhexidine gel was evaluated by counting the number of colony forming units. After 14 days of intracanal medication, there was a significant decrease in the number of C. albicans colony forming units at a depth of 0-100 µm with chlorhexidine treatment either with or without calcium hydroxide compared with the calcium hydroxide only treatment. However, there were no differences in the number of colony forming units at the 100-200 µm depth for any of the medications investigated. C. albicans viability was also evaluated by vital staining techniques and fluorescence microscopy analysis. Antifungal activity against C. albicans significantly increased at both depths in the chlorhexidine groups with and without calcium hydroxide compared with the groups treated with calcium hydroxide only. Treatments with only chlorhexidine or chlorhexidine in combination with calcium hydroxide were effective for elimination of C. albicans.

Envolvimento de sinais coestimulatórios na periodontite apical crônica em humanos / Co-stimulatory signals in chronic periapical periodontitis

As lesões periapicais são induzidas por uma infecção crônica da polpa dental. Antígenos microbianos estimulam a resposta imune específica e inespecífica nos tecidos apicais. Como consequência desse processo, diante da incapacidade das defesas do hospedeiro para erradicar a infecção, uma lesão periapical é formada, com o objetivo de restringir a invasão microbiana. O desenvolvimento da periodontite apical crônica depende de uma fina regulação da ativação dos linfócitos. A ativação das células T requer dois sinais, um mediado pelo complexo TCR, após o reconhecimento do antígeno, e o outro mediado pela interação dos receptores coestimulatórios. CD28 é um receptor coestimulatório, enquanto CTLA-4 e PD-1 induzem um sinal inibitório para a ativação de células T. Para compreender o envolvimento de células T na periodontite apical crônica, avaliamos a presença destas células na lesão periapical e os fatores coestimulatórios, citocinas e espécies reativas do oxigênio que estas células estariam produzindo. As amostras analisadas foram de tecido gengival para o grupo controle (n = 20) e lesões periapicais para o grupo com periodontite apical crônica (n = 20). Quanto ao perfil celular das lesões periapicais, os resultados mostraram que linfócitos T (59,3 ± 3,7%) foram as células predominantes, sendo a subpopulação CD4+ (72,7 ± 3,4%) a mais encontrada. A seguir, verificou-se a expressão de moléculas de superfície em células T. Observou-se que a expressão de CD28 (0,5 ± 0,5%) foi significativamente mais baixa em amostras de lesões periapicais que no grupo controle principalmente para linfócito T CD8+. Já CTLA-4 foi identificado em altos níveis para pacientes com periodontite apical tanto para CD3+CD4+ (86,1 ± 2,6%) quanto para CD3+CD8+ (59,8 ± 8,6%). PD-1 (73,5 ± 5,6%) e PD-L1 (59,8 ± 8,6%) apresentaram alta positividade para CD3+CD4+. Esses resultados indicaram um possível envolvimento da via de sinalização de PD-1 e PD-L1 na modulação da resposta de células T de...

Periapical lesions are induced by the chronic infection of dental pulp. Microbial antigens stimulate both non-specific and specific immune response in periapical tissue. As a consequence of these processes and the inability of host defense mechanisms to eradicate infection, chronic periapical lesion are formed, with the aim of restricting microbial invasion. Negative co-stimulatory signals mediated via cell surface molecules such as cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) and programmed death-1 (PD-1) play a critical role in down- modulation immune responses and maintaining peripheral tolerance. Both CTLA-4 and PD-1 are induced on actived T cell, and these are involved in the immunophatogenesis of periapical lesions. Inhibitory signals mediated via molecules such as programmed-death-1 (PD-1) play a critical role in down-modulating immune responses and maintaining peripheral tolerance. We investigated the involvement of cytokines and PD-1 engagement in mediating the T cell activation in chronic periapical diseases. Gingival samples from healthy individuals (n= 20) and patients with chronic periapical periodontitis (n= 20) were collected and used for the subsequent assays. The leukocytes in the lesion site were evaluated using flow cytometry. The production of cytokines interferon-gamma (IFN-), interleukin (IL)-10, tumor necrosis factor-alpha (TNF-) and transforming growth factor-beta (TGF-) was evaluated by ELISA. We observed a significant increase in the total number of leukocytes from periapical lesions as compared with healthy group. Our results for the composition of infiltrating cell in periapical lesion showed that the predominant cells were lymphocytes T (59,3 ± 3,7%) and contained a higher proportion of CD4+ cells (72,7 ± 3,4%). T cells from patients with periapical lesions expressed significantly higher levels of PD-1 (73,5 ± 5,6%) and PD-L1 (59,8 ± 8,6%). The levels of CTLA-4 were higher in CD3+CD4+ (86,1± 2,6%) and CD3+...

Evaluation of single root canals filled using the lateral compaction, tagger's hybrid, microseal and guttaflow techniques.

The aim of this study was to determine the percentage of voids, gutta-percha and root canal sealer using 4 different filling techniques. Fifty-two extracted maxillary lateral incisors were prepared using the crown-down pressureless technique. The teeth were randomly divided in 4 groups (n=13): Lateral compaction (LC), Tagger's hybrid (TH), MicroSeal (MS) and GuttaFlow (GF) techniques. Horizontal cross-sections were made at the 2, 10 and 15 mm levels from the apex. Digital images of the root canal areas were acquired using a stereomicroscope and examined using the Image Tool 3.0 software. Statistical analysis was performed using the Kruskal-Wallis test (α=0.05). In general, a significant decrease in the gutta-percha filled area and increase of sealer area were observed at the apical level for all the evaluated techniques (p<0.05). With regard to the presence of voids, no significant difference was found. MS and TH techniques showed a larger gutta-percha filled area than LC and GF techniques at the coronal and middle third level (p<0.05). From the results of the present study, it may be concluded that the gutta-percha filled area of fillings decrease at the apical level, regardless of the filling technique used.

Evaluation of single root canals filled using the lateral compaction, tagger's hybrid, microseal and guttaflow techniques

The aim of this study was to determine the percentage of voids, gutta-percha and root canal sealer using 4 different filling techniques. Fifty-two extracted maxillary lateral incisors were prepared using the crown-down pressureless technique. The teeth were randomly divided in 4 groups (n=13): Lateral compaction (LC), Tagger's hybrid (TH), MicroSeal (MS) and GuttaFlow (GF) techniques. Horizontal cross-sections were made at the 2, 10 and 15 mm levels from the apex. Digital images of the root canal areas were acquired using a stereomicroscope and examined using the Image Tool 3.0 software. Statistical analysis was performed using the Kruskal-Wallis test (α=0.05). In general, a significant decrease in the gutta-percha filled area and increase of sealer area were observed at the apical level for all the evaluated techniques (p<0.05). With regard to the presence of voids, no significant difference was found. MS and TH techniques showed a larger gutta-percha filled area than LC and GF techniques at the coronal and middle third level (p<0.05). From the results of the present study, it may be concluded that the gutta-percha filled area of fillings decrease at the apical level, regardless of the filling technique used.

O objetivo do estudo foi determinar a porcentagem de espaços vazios, guta-percha e cimento após a obturação por 4 diferentes técnicas. Cinquenta e dois incisivos laterais superiores humanos extraídos foram instrumentados pela técnica coroa-ápice sem pressão. Os dentes foram randomicamente divididos em 4 grupos (n=13): Condensação lateral (LC), Técnica híbrida de Tagger (TH), MicroSeal (MS) e GuttaFlow (GF). Foram feitas secções horizontais a 2, 10 e 15 mm do ápice. Imagens digitais foram obtidas dos canais por meio de estereomicroscópio e analisadas no programa Image Tool 3.0. A análise estatística foi feita utilizando o teste de Kruskal-Wallis (α=0,05). Em geral foi observado um significante decréscimo na área de guta-percha e um aumento na área de cimento para todas as técnicas analisadas (p<0,05). Com relação à presença de espaços vazios, não houve diferença estatística entre as técnicas (p>0,05). As técnicas MS e TH apresentaram área de guta-percha maior que as técnicas LC e GF nos terços médio e cervical (p<0,05). Após análise dos resultados foi possível concluir que a área de guta-percha nas obturações diminui em sentido apical, independente da técnica utilizada.