Influence of melatonin supplementation on tissue response of endodontic sealers in Wistar rats.

OBJECTIVE: This study evaluated the influence of melatonin supplementation on tissue's response of endodontic sealers in Wistar rats. METHODOLOGY: Forty-eight rats received subcutaneous implants of four polyethylene tubes: one empty (control) and three filled with endodontic sealers (AH Plus, Endofill and Sealapex). Half of the animals were supplemented with melatonin (ME) and the remaining treated with water (WA) for 15 days before the implantation until euthanasia, forming the groups: control-WA, AH Plus-WA, Endofill-WA, Sealapex-WA, Control-ME, AH Plus-ME, Endofill-ME and Sealapex-ME. After 5, 15 and 30 days, (n = 8) tubes were removed and evaluated in H&E., immunohistochemistry, PSR, VK and POL. The results were statistically analyzed (p < 0.05). RESULTS: In animals treated with water, Endofill-WA evoked more intense inflammatory infiltrate compared to AH Plus-WA and Control-WA in a 30-day period (p < 0.05). In animals supplemented with melatonin, there was any difference among endodontic sealers' response in any period of analysis (p > 0.05). Comparing the individual response of each sealer, over a 30-day period, Endofill-ME and Sealapex-ME showed less inflammatory infiltrate compared to Endofill-WA and Sealapex-WA, respectively (p < 0.05). Immunostaining for IL-6 and TNF-α was less intense for all groups in animals supplemented with melatonin, in most periods, except for the Endofill sealer (p < 0.05). Furthermore, Endofill-ME at 5 days and AH-Plus-ME at 30 days showed a higher percentage of mature collagen fibers compared to the Endofill-WA and AH Plus-WA, respectively (p < 0.05). Positive structures for von Kossa staining and birefringent to polarized light were observed only for Sealapex-WA and Sealapex-ME in all periods. CONCLUSIONS: It can be concluded that melatonin influences the tissue response to endodontic sealers, modulating the inflammatory and reparative process.

Tissue response after subcutaneous implantation of different glass ionomer-based cements

Abstract The aim of this study was to evaluate the subcutaneous connective tissue response of isogenic mice after implantation of different glass ionomer-based cements (EQUIA® Forte Fil, EQUIA® Fil and Ketac™ Universal Aplicap™). Eighty-seven isogenic BALB/c mice were allocated in 12 groups, 9 were considered as experimental groups (Ketac, E. Fil and E. Forte at 7, 21 and 63 days) and 3 controls (empty polyethylene tubes at 7, 21 and 63 days). After the experimental periods, the subcutaneous connective tissue surrounding the implanted material was removed and subjected to histotechnical processing and staining with hematoxylin and eosin. A histopathological description of the tissue reaction surrounding each material and a semi-quantitative analysis of collagen fiber formation and inflammatory infiltrate were performed. Additionally, the thickness of the granulomatous tissue in contact with each material was measured. Data were analyzed statistically (α=0.05) by the Kruskal-Wallis test, followed by Dunn post-test. Initially, the collagen fiber formation was not different among all the tested materials (p>0.05) but was different at 21 days with the control group presenting the most advanced stage of collagen fiber formation. At 63 days, EQUIA® Forte Fil group showed the most advanced stage of collagen fiber formation, compared to EQUIA® Fil group (p<0.05). The inflammatory infiltrate was not different among the tested materials in any experimental period (p>0.05). The thickness of the granulomatous tissue was greater in the E. Forte group, compared to control in all periods. All glass ionomer-based cements showed tissue compatibility, according to the evaluated parameters.

Resumo O objetivo deste estudo foi avaliar a resposta subcutânea do tecido conjuntivo de camundongos isogênicos após o implante de diferentes cimentos à base de ionômero de vidro (EQUIA® Forte Fil, EQUIA® Fil e Ketac ™ Universal Aplicap ™). Oitenta e sete camundongos isogênicos BALB/c foram alocados em 12 grupos, 9 como grupos experimentais (Ketac, E. Fil e E. Forte aos 7, 21 e 63 dias) e 3 controles (tubos de polietileno vazios aos 7, 21 e 63 dias). Após os períodos experimentais, o tecido conjuntivo subcutâneo ao redor do material implantado foi removido e submetido ao processamento histotécnico e coloração com hematoxilina e eosina. Uma descrição histopatológica da reação tecidual envolvendo cada material e uma análise semi-quantitativa da fibrose e infiltrado inflamatório foram realizadas. Além disso, foi realizada a mensuração da espessura do tecido granulomatoso em contato com cada material. Os dados foram analisados estatisticamente (α=0,05) pelo teste de Kruskal-Wallis, seguido do pós-teste de Dunn. Inicialmente, a fibrose não foi diferente entre todos os materiais testados (p>0,05), mas foi diferente aos 21 dias, com o grupo controle apresentando o estágio mais avançado de fibrose. Aos 63 dias, o grupo EQUIA® Forte Fil apresentou o estágio mais avançado de fibrose, comparado ao grupo EQUIA® Fil (p<0,05). O infiltrado inflamatório não foi diferente entre os materiais testados em nenhum período experimental (p>0,05). A espessura do tecido granulomatoso foi maior no grupo E. Forte, comparado ao controle em todos os períodos. Todos os cimentos à base de ionômero de vidro apresentaram compatibilidade tecidual, de acordo com os parâmetros avaliados.

Impact of infected and noninfected human dentine debris on bone healing in rats.

AIM: To evaluate in vivo the bone tissue response of rats to varying amounts of infected and noninfected dentine debris. METHODOLOGY: Bone tissue reactions were evaluated histologically in 42 Wistar rats after 7, 30 and 60 days. For each animal, three surgical cavities were prepared on the femur and filled with varying amounts (5, 10 or 20 mg) of infected or noninfected dentine debris pellets. In the negative control group, the surgical cavities were not filled. At the end of each experimental period, the animals were euthanized. The samples were processed histologically and analysed using a light microscope. The presence and the severity of inflammatory reaction, as well as hard tissue deposition were evaluated. Data were subjected to statistical analysis and the effects of the dependent variables calculated using nonparametric tests Kruskal-Wallis and Mann-Whitney U with due Bonferroni corrections at P = 0.05. RESULTS: At 7 days, the presence of infected debris significantly increased the histopathological scores for neutrophils (P < 0.05), and abscess formation (P < 0.05). Noninfected debris scored significantly higher for lymphocyte infiltrate compared with the control group and infected debris (P < 0.05). Both infected and noninfected debris equally triggered eosinophil cells compared with no-dentine (P < 0.05). As for giant cells and macrophages, no difference was detected amongst the dentine groups (P > 0.05). Hard tissue deposition was similar regardless of the presence or the bacteriological status of the dentine (P = 1.00). None of the above histopathological parameters was significantly influenced by the amount of debris (P > 0.05). For all parameters evaluated, at 7 days of analysis, the inflammatory response was significantly more intense compared with 30 and 60 days (P < 0.05). Inflammatory parameters were scored similarly for the evaluated groups after 30 and 60 days (P > 0.05). However, hard tissue deposition has significantly increased after 30 days (P < 0.05). No difference was seen between 30 and 60 days of analysis (P = 1.00) for all histological parameters evaluated. CONCLUSION: The assumption that the amount of extruded debris may negatively affect the inflammatory response of bone tissue was not validated in the present in vivo animal study. Infected dentine may trigger acute inflammatory parameters especially during the first 7 days of contact with the tissue; however, in the long term, these negative effects are mitigated.

Biocompatibility of a New Dental Glass Ionomer Cement with Cellulose Microfibers and Cellulose Nanocrystals

Resumo Os novos materiais restauradores em desenvolvimento devem evitar danos aos tecidos dentários. Portanto, o objetivo deste estudo foi avaliar a biocompatibilidade de uma marca comercial de cimento de ionômero de vidro convencional (CIV) modificado com microfibras de celulose (CIV+MC) ou nanocristais de celulose (CIV+NC) através da implantação de três amostras em tecido subcutâneo na região dorsal de 15 ratos Rattus norvegicus albinus. Cada rato recebeu um exemplar de cada cimento, resultando nos seguintes grupos (n=15): Grupo CIV (controle, n=15), Grupo CIV+MC e Grupo CIV+NC. Nos intervalos de 7, 30 e 60 dias os animais foram sacrificados e os seguintes aspectos foram avaliados histologicamente: tipo de células inflamatórias, fibroblastos, vasos sanguíneos, macrófagos, células gigantes, tipo de reação inflamatória e espessura da cápsula (µm). Estes eventos foram quantitativamente classificados conforme os escores: (-) ausente, (+) suave, (++) moderado e (+++) intenso. Os resultados foram analisados estatisticamente pelo teste Kruskal-Wallis e pós-teste Mann-Whitney. Aos 7 dias, o Grupo CIV+NC demonstrou um nível mais elevado de reparação tecidual porque havia maior quantidade de fibroblastos (p=0,022) e uma menor quantidade de macrófagos (p=0,008) e células mononucleares (p=0,033). Neutrófilos e células gigantes estavam ausentes em todos os períodos experimentais. Aos 60 dias, o Grupo CIV+NC apresentou cápsula de tecido fibroso com espessura mais reduzida (26,72±2,87 µm) em comparação ao Grupo CIV+MC (41,21±3,98 µm (p=0,025). No geral, todos os materiais apresentaram satisfatória biocompatibilidade, no entanto, o cimento de ionômero de vidro modificado com nanocristais de celulose proveu reparação tecidual mais avançada comparativamente aos demais materiais avaliados.

Developing new restorative materials should avoid damage to tissue structures. This study evaluated the biocompatibility of a commercial dental glass ionomer cement (GIC) mechanically reinforced with cellulose microfibers (GIC+CM) or cellulose nanocrystals (GIC+CN) by implantation of three test specimens in subcutaneous tissue in the dorsal region of 15 Rattus norvegicus albinus rats. Each rat received one specimen of each cement, resulting in the following groups (n=15): Group GIC (Control), Group GIC+CM and Group GIC+NC. After time intervals of 7, 30 and 60 days, the animals were sacrificed and the following aspects were histologically evaluated: type of inflammatory cells, fibroblasts, blood vessels, macrophages, giant cells, type of inflammatory reaction and capsule thickness (µm). These events were scored as (-) absent, (+) light, (++) moderate and (+++) intense. The results were statistically analyzed by Kruskal-Wallis test and Mann-Whitney post test. At 7 days, Group GIC+NC showed more favorable tissue repair because quantitatively there were more fibroblasts (p=0.022), fewer macrophages (p=0.008) and mononuclear cells (p=0.033). Polymorphonuclear neutrophils and giant cells were absent in all experimental periods. At 60 days, test specimens in Group GIC+NC were surrounded by a fibrous tissue capsule with reduced thickness (26.72±2.87 µm) in comparison with Group GIC+CM (41.21±3.98 µm) (p=0.025). In general, all biomaterials showed satisfactory biocompatibility, but glass ionomer cement modified with cellulose nanocrystals showed a more advanced tissue repair.

Novel endodontic sealers induce cell cytotoxicity and apoptosis in a dose-dependent behavior and favorable response in mice subcutaneous tissue.

OBJECTIVES: The objective of the present study is to evaluate the in vitro cytotoxicity and in vivo biocompatibility of two novel endodontic sealers: RealSeal XT1 and Sealapex Xpress on the subcutaneous connective tissue of mice. MATERIALS AND METHODS: The cytotoxicity was assessed by cell viability using the MTT assay (one-way ANOVA), trypan blue test (Mann-Whitney) and cell apoptosis by flow cytometer. For the subcutaneous study, polyethylene tubes filled with the sealers were implanted in 70 BALB/c mice: 6 experimental groups (n = 10/group) and 2 control groups with empty tubes (n = 5/group). At the end of experimental periods (7, 21, and 63 days), the tissue was removed and histotechnically processed. Angioblastic proliferation and edema (Fisher's exact test) were evaluated, besides thickness measurement (µm) of the reactionary granulomatous tissue and neutrophil counts (Kruskal-Wallis and Dunn's post test; Mann-Whitney) (α = 0.05). RESULTS: MTT assay, trypan blue, and analysis of apoptotic cells showed a dose-dependent direct effect: the more diluted the sealer, the less cytotoxic. Regarding the angioblastic proliferation and edema, difference between the sealers at 7 and 63 days occurred (p < 0.05). Both endodontic sealers initially promoted perimaterial tissue reaction as a foreign body granuloma and thus stimulated favorable tissue responses. CONCLUSIONS: Both sealers showed a dose-dependent effect and promoted satisfactory subcutaneous tissue response; the sealer Sealapex Xpress was less cytotoxic and more biocompatible than RealSeal XT. CLINICAL RELEVANCE: The step of root canal filling during endodontic treatment is highly important for the preservation of the periapical tissue integrity. Subcutaneous reaction to endodontic sealers enables scientific basis for clinical use.

eHSP70/iHSP70 and divergent functions on the challenge: effect of exercise and tissue specificity in response to stress.

Heat-shock proteins including HSP70 are stress-related proteins that have been reported in cell protection and survival. In contrast to this, the increase in circulating levels of HSP70 (eHSP70) is associated with cellular damage and inflammatory factors. Physical stress, like exercise, is effective to induce both iHSP70 and eHSP70 in several tissues and cell types, which have different behaviours in response to stress. The different functions of HSP70 before the challenge are dependent of intracellular localization and subsequent molecular chaperone action, but when present in the extracellular space, it activates pro-inflammatory pathways. The different forms in which tissues and cells respond to stress like physical exercise, as well as the optimal intensity of the stress, are determinants for the beneficial effects or as an indicator of dangerous conditions, summoning immune cells as a warning sign to the body.

Resin luting materials: Tissue response in dog's teeth.

The aim of this study was to evaluate radiographically and histologically the pulpal and periapical response to self-adhesive (Rely X™ Unicem) and self-etching and self-curing (Multilink(®)) resin-based luting materials in deep cavities in dogs' teeth. Deep class V cavities (0.5-mm-thick dentin) were prepared in 60 canine premolars and the following materials were applied on cavity floor: Groups I/V-RelyX™ Unicem; Groups II/VI-Multilink(®); Groups III/VII-zinc phosphate cement (control) and; Groups IV/VIII-gutta-percha (control). Cavities were restored with silver amalgam. Animals were euthanized after 10 days (groups I-IV) and 90 days (groups V-VIII). Tooth/bone blocks were radiographed and processed for histopathological evaluation of pulp and periapical tissue response to the materials. All materials presented similar histopathological features and radiographic findings at both periods. The pulp tissue was intact. The apical and periapical regions and periodontal ligament thickness were normal. No inflammatory cells, resorption of mineralized tissue (dentin, cementum, and alveolar bone) or bacteria were observed. The lamina dura was intact and no areas of periapical bone rarefaction or internal/external root resorption were observed radiographically. It can be concluded that Rely X™ Unicem and Multilink(®) caused no adverse tissue reactions and may be indicated for cementation of indirect restorations in deep dentin cavities without pulp exposure.

In vivo evaluation of tissue response to new endodontic sealers

Introduction: The sealers can be in direct contact with the periapical tissues. Thus, these materials must have appropriate physical and biological properties, providing conditions for repair to occur. Objective: The aim of this study was to evaluate the response of rat subcutaneous tissue to endodontics sealers. Material and methods: Three materials comprised the groups: group I - Zinc Oxide, Eugenol and Iodoform paste, group II - Portland cement with propylene glycol, and group III - MTA Fillapex® (Angelus). These materials were placed in polyethylene tubes and implanted into dorsal connective tissue of Wistar rats for seven and 15 days. The specimens were stained with hematoxylin and eosin and evaluated regarding to inflammatory reaction parameters through a light microscope. The data were compared using Kruskal-Wallis test with significance level of 5%. The intensity of inflammatory response against the sealers was analyzed by two blinded and previously calibrated observers for all experimental periods. Results: The histological evaluation showed that all the materials caused a moderated inflammatory reaction at seven days which decreased with time. A greater inflammatory reaction was observed at seven days in group I. The other specimens had significantly less inflammatory cells when compared to this group. Tubes with MTA Fillapex® presented some giant cells, macrophages and lymphocytes after seven days. At 15 days, the presence of fibroblasts and collagen fibers was observed indicating normal tissue healing. The group II showed similar results to those observed in MTA Fillapex® already at seven days. At 15 days the inflammatory reaction presented was almost absent at the tissue, with many collagen fibers indicating normal tissue healing. Statistical analysis showed a significant statistical difference amongst the group I (seven days) and II (15 days) (p < 0.05). In the other groups no significant statistical differences were observed. Conclusion: MTA Fillapex® and Portland cement with propylene glycol were more biocompatible than the other tested cements.

Subcutaneous connective tissue response to primary root canal filling materials

This study evaluated the response of the subcutaneous connective tissue of BALB/c mice to root filling materials indicated for primary teeth: zinc oxide/eugenol cement (ZOE), Calen paste thickened with zinc oxide (Calen/ZO) and Sealapex sealer. The mice (n=102) received polyethylene tube implants with the materials, thereby forming 11 groups, as follows: I, II, III: Calen/ZO for 7, 21 and 63 days, respectively; IV, V, VI: Sealapex for 7, 21 and 63 days, respectively; VII, VIII, IX: ZOE for 7, 21 and 63 days, respectively; X and XI: empty tube for 7 and 21 days, respectively. The biopsied tissues were submitted to histological analysis (descriptive analysis and semi-quantitative analysis using a scoring system for collagen fiber formation, tissue thickness and inflammatory infiltrate). A quantitative analysis was performed by measuring the area and thickness of the granulomatous reactionary tissue (GRT). Data were analyzed by Kruskal-Wallis, ANOVA and Tukey's post-hoc tests (?=0.05). There was no significant difference (p>0.05) among the materials with respect to collagen fiber formation or GRT thickness. However, Calen/ZO produced the least severe inflammatory infiltrate (p<0.05). The area of the GRT was significantly smaller (p<0.05) for Calen/ZO and Sealapex. In conclusion, Calen/ZO presented the best tissue reaction, followed by Sealapex and ZOE.

Neste estudo avaliou-se a resposta do tecido conjuntivo subcutâneo de camundongos BALB/c a materiais obturadores de canal radicular de dentes decíduos: óxido de zinco/eugenol (OZE), pasta Calen® espessada com óxido de zinco (Calen/OZ) e cimento Sealapex®. Os camundongos (n=102) receberam implantes de tubos de polietileno??? e foram divididos em grupos: I, II, III - Calen/OZ (7, 21 e 63 dias, respectivamente); IV, V, VI - Sealapex (7, 21 e 63 dias, respectivamente); VII, VIII, IX - OZE (7, 21 e 63 dias, respectivamente); X, XI - tubo vazio (7 e 21 dias, respectivamente). Os tecidos foram submetidos ao processamento e análise histopatológica descritiva e por meio de escores do fibrosamento, espessura tecidual e infiltrado inflamatório. Para a análise quantitativa mensurou-se a área e a espessura do tecido granulomatoso reacional (TGR). Os resultados foram analisados pelos testes de Kruskal-Wallis, ANOVA e pós-teste de Tukey (?=0,05). Não houve diferença significante (p>0,05) entre os materiais, com relação ao fibrosamento e à espessura do TGR. Contudo, Calen/OZ apresentou infiltrado inflamatório de menor intensidade (p<0,05). A área do TGR foi menor (p<0,05) para Calen/OZ e Sealapex. Pôde-se concluir que Calen/OZ foi o material que apresentou a melhor compatibilidade tecidual, seguido pelos cimentos Sealapex e OZE.

Subcutaneous tissue response of isogenic mice to calcium hydroxide-based pastes with chlorhexidine

This study was evaluated the response of subcutaneous connective tissue of isogenic mice to calcium hydroxide-based pastes with chlorhexidine digluconate (CHX). Seventy isogenic male BALB/c mice aged 6-8 weeks and weighing 15-20 g were randomly assigned to 8 groups. The animals received polyethylene tube implants as follows: Groups I, II, and III (n=10) - Calen® paste mixed with 0.4 percent CHX (experimental paste; Calen/CHX) for 7, 21, and 63 days, respectively; Groups IV, V, and VI (n=10) - UltraCal™ paste mixed with 2 percent CHX (experimental paste supplied by Ultradent Products Inc.; Ultracal/CHX) for 7, 21, and 63 days, respectively; and Groups VII and VIII (n=5): empty tube for 7 and 21 days, respectively. At the end of the experimental periods, the implants were removed together with the surrounding tissues (skin and subcutaneous connective tissue). The biopsied tissues were subjected to routine processing for histological analysis. Using a descriptive analysis and a four-point (0-3) scoring system, the following criteria were considered for qualitative and quantitative analysis of the tissue around the implanted materials: collagen fiber formation, tissue thickness and inflammatory infiltrate. A quantitative analysis was performed by measuring the thickness (µm), area (µm²) and perimeter (µm) of the reactionary granulomatous tissue formed at the tube ends. Data were analyzed statistically by the Kruskal-Wallis test and Dunn's post-test (á=0.05). Calen/CHX showed biocompatibility with the subcutaneous and reactionary tissues, with areas of discrete fibrosis and normal conjunctive fibrous tissue, though without statistically significant difference (p>0.05) from the control groups. In Groups I to III, there was a predominance of score 1, while in Groups IV to VI scores 2 and 3 predominated for all analyzed parameters. UltraCal/CHX, on the other hand, induced the formation of an inflammatory infiltrate and abundant exudate, ...

O objetivo do presente estudo foi avaliar a resposta do tecido conjuntivo subcutâneo de camundongos isogênicos frente a pastas à base de hidróxido de cálcio, associadas ao digluconato de clorexidina (CHX). Setenta camundongos isogênicos BALB/c machos, com 6-8 semanas e pesando 15-20 g foram aleatoriamente divididos em 8 grupos. Os animais receberam implantes de tubos de polietileno contendo: Grupos I, II e III (n=10) - pasta Calen® associada à CHX a 0,4 por cento (Calen/CHX), por 7, 21 e 63 dias, respectivamente; Grupos IV, V e VI (n=10) - pasta UltraCal™ associada à CHX a 2 por cento (pasta experimental fornecida pela Ultradent Products Inc.; Ultracal/CHX), por 7, 21 e 63 dias, respectivamente; e Grupos VII e VIII (n=5) - tubo de polietileno vazio, por 7 e 21 dias, respectivamente. Decorridos os períodos experimentais, os implantes foram removidos juntamente com os tecidos circundantes (pele e tecido conjuntivo). Os tecidos foram submetidos ao processamento histotécnico de rotina, para análise histopatológica. Empregando um sistema de escores, os seguintes critérios foram considerados para a análise qualitativa e quantitativa: fibrosamento, espessura tecidual e infiltrado inflamatório. Foi efetuada, também, a análise quantitativa da medida da espessura (µm), área (µm²) e perímetro (µm) do tecido granulomatoso reacional formado na abertura dos tubos. Os dados obtidos foram submetidos à análise estatística, empregando o teste de Kruskal-Wallis e o pós-teste de Dunn. O nível de significância adotado foi de 5 por cento. Os resultados demonstraram biocompatibilidade da pasta Calen associada à CHX a 0,4 por cento com o tecido adjacente, com fibrosamento discreto, assim como tecido conjuntivo normal, sem diferença estatística significante com os controles (p>0,05). Nos Grupos I, II e III houve predominância do escore 1, enquanto que nos Grupos IV, V e VI houve predominância dos escores 2 e 3, em todos os parâmetros analisados. Em relação ...