Selenium intracanal dressing: effects on the periapical immune response.

OBJECTIVES: To evaluate the selenium (Se) behavior when used as an endodontic dressing in teeth with pulp necrosis. Additionally, its effects was also compared with the calcium hydroxide (C.H.), which is used globally as a root canal dressing, and the combination of the C.H. with Se (C.H. + Se). MATERIALS AND METHODS: The sample consisted of 60 patients requiring endodontic treatment who were divided into groups, i.e., without intracanal medication (empty) and with medications as follows: selenium (Se), calcium hydroxide (C.H.), and calcium hydroxide + selenium (C.H. + Se) (n = 15). After the coronary opening, three absorbent paper points were placed in the RCS and maintained for 2 min for microbial evaluation. Following the cleaning and shaping procedures, new paper points were introduced into the root canal system, passing passively through the root apex (2 mm) into the periapical tissues for 2 min, for immune evaluation. The collections were performed again 15 days later. Real-time PCR quantified the expression of the prokaryotic 16S ribosomal RNA. The 16S mRNA was evaluated before the cleaning and shaping procedures and 15 days later in the groups treated with or without medication. RESULTS: A significant reduction in the microbial load was observed only in the groups that received endodontic dressing (p < 0.05). The cytokines IFN-γ, TNF-α, IL-1α, IL-17A, IL-10, IL-6 and MCP-1, were also quantified by real-time PCR. There was an increase in the gene expression level of the cytokines (T15) TNF-α and IL-10 in the C.H. group compared to the other groups (p < 0.05). The IFN-γ mRNA expression was reduced in the groups treated with the medications (Se, C.H., and C.H. + Se). CONCLUSIONS: The findings of the present study indicate that in the case of treatment over multiple sessions, the use of root canal dressing is essential to avoid the root canal system (RCS) microbial recolonization. Selenium potentiated the effects of calcium hydroxide inducing an anti-inflammatory response in periapical tissues. CLINICAL RELEVANCE: Se is a mineral essential for the formation of the amino acid selenocysteine, which is directly involved in the maintenance of the immune response. Selenium has been widely used in the medical field in the treatment of cancer, as an activator of bone metabolism, and as a stimulator of the immune system. In this study, it was shown that the incorporation of Se, whether as intracanal medication alone or in conjunction with other medications, may potentiate periapical tissue repair after RCS cleaning and shaping procedures.

Resposta imune periapical à medicação intracanal à base de hidróxido de cálcio e selênio / Periapical immune response to intracanal medication based on calcium hydroxide and selenium

O tratamento endodôntico tem como objetivo eliminar a contaminação microbiana dos sistemas de canais radiculares (SCR) por meio da instrumentação mecânica e irrigação química (PMQ). Quando não for possível a resolução em uma única sessão, o SCR deverá ser preenchido com uma medicação intracanal para evitar a recolonização microbiana tardia. O presente estudo teve como objetivo avaliar a ação do hidróxido de cálcio, mundialmente utilizado como medicação intracanal, associado ao selênio (H.C + Se), em dentes portadores de necrose pulpar. A amostra foi composta por 60 pacientes que possuiam dentes com indicação de tratamento endodôntico, divididos em grupos (n=15): sem medicação intracanal (Empty); que foram medicados com hidróxido de cálcio (H.C), Selênio (Se) e hidróxido de cálcio + selênio (H.C + Se). Após a abertura coronária, 3 cones de papel absorvente foram inseridos no terço inicial do conduto e mantidos por 2 min para avaliação microbiana. Após o PMQ, novos cones foram introduzidos nos SCR, ultrapassando-se 2mm do ápice radicular, e mantidos no tecido perirradicular por 2min para a coleta do fluido intersticial periapical. A coleta foi novamente realizada 15 dias após o PMQ. A expressão gênica do mRNA do fragmento 16S de procariontes, das citocinas INF-γ, TNF-α, IL-1α, IL-17A, IL-10, IL-6 e MCP-1 foram quantificadas por PCR em tempo real. O mRNA 16S foi avaliado antes do PMQ e 15 dias após, nos grupos sem medicação e com medicação intracanal. A redução significativa da carga microbiana foi observada apenas no grupo com medicação intracanal (p<0,05). Observou-se um aumento da expressão gênica das citocinas (T15) TNF-α e IL-10 no grupo H.C+Se em comparação aos demais grupos (p<0,05). A expressão de mRNA de IFN-γ reduziu nos grupos tratados com as medicações (H.C, Se, H.C + Se). Conclui-se que o uso de medicação intracanal é imprescindível para se evitar a recolonização do SCR. A inclusão do selênio na pasta de hidróxido de cálcio resultou na potencialização da expressão de citocinas que permitirão o reparo dos tecidos perirradiculares.

Endodontic treatment aims to eliminate the microbial contamination of the root canal system (RCS) and is achieved with the use of mechanical instrumentation and chemical irrigation. When resolution in a single session is not possible, the RCS should be filled with intracanal medication to avoid subsequent recolonization. The present study aimed to evaluate the effect of calcium hydroxide, wich is used globally as an intracanal medication, in combination with selenium (CH + Se) as an intracanal medication in teeth with pulp necrosis. The sample consisted of 60 patients requiring endodontic treatment who were divided into groups: without intracanal medication (empty) and with medication; calcium hydroxide (CH), selenium (Se) and calcium hydroxide + selenium (CH + Se) (n = 15). After the coronary opening, three absorbent paper cones were inserted in the initial third of the RCS and maintained for 2min for microbial evaluation. After the cleaning and shaping procedures, new cones were introduced into the RCS, extending 2 mm from the root apex and were kept in the periradicular tissue for 2 min' to collect the periapical fluid. The collection was also performed 15 days later. Real time PCR was used to quantify the expression of the prokaryotic 16S ribosomal RNA gene. Additionally, the cytokines IFN-γ, TNF-α, IL-1α, IL-17A, IL-10, IL-6 and MCP-1 were also quantified by real-time PCR. The 16S mRNA was evaluated before the cleaning and shaping procedures and 15 days later in the groups treated with or without medication. A significant reduction in the microbial load was observed only in the intracanal group (p <0.05). There was an increase in the gene expression level of the cytokines (T15) TNF-α and IL-10 in the CH+ group compared to the other groups (p <0.05). The expression of IFN-γ mRNA was reduced in the groups treated with the medications (CH, Se, and CH + Se). The findings of the present study indicate that in the case of treatment over multiple sessions, the use of intracanal medication is essential to avoid the recolonization of the RCS. The inclusion of selenium with calcium hydroxide resulted in the potentiation of the anti-inflammatory phase of the periradicular tissues.

Experimental furcal perforation treated with mineral trioxide aggregate plus selenium: immune response.

The aim of this study is to evaluate the expression of cytokines in response to mineral trioxide aggregate (MTA) plus selenium in germ-free mice with experimental furcal perforation. The first left maxillary molar was opened, and the furcal area was perforated and treated with post-MTA-Se (experimental group). The same surgical intervention was performed for the maxillary right first molar, which was treated with MTA (control group). Fifteen mice were sacrificed 7, 14, and 21 days after furcal perforation, and periapical tissue samples were collected. The mRNA expression levels of the cytokines TGF-ß, TNF-α, IFN-γ, HPRT, IL-10, IL-4, RANK, RANKL, IL-1, and IL-17 were assessed by using real-time polymerase chain reaction. In the experimental group, at 21-days post-MTA-Se sealing, the mRNA levels of TNF-α and IL-10 were upregulated compared with those in the control group (p < 0.05). Futher assessment revealed basal mRNA expression levels of IL-1α, IFN-γ, RANK, RANKL, IL-17A, IL-4, and TGF-ß, over long experimental times, in both the experimental and control groups (p > 0.05). In conclusion, MTA+Se sealing favoured increased expression of IL-10 and TNF-α at later time points (day 21).

Experimental furcal perforation treated with mineral trioxide aggregate plus selenium: immune response

Abstract The aim of this study is to evaluate the expression of cytokines in response to mineral trioxide aggregate (MTA) plus selenium in germ-free mice with experimental furcal perforation. The first left maxillary molar was opened, and the furcal area was perforated and treated with post-MTA-Se (experimental group). The same surgical intervention was performed for the maxillary right first molar, which was treated with MTA (control group). Fifteen mice were sacrificed 7, 14, and 21 days after furcal perforation, and periapical tissue samples were collected. The mRNA expression levels of the cytokines TGF-β, TNF-α, IFN-γ, HPRT, IL-10, IL-4, RANK, RANKL, IL-1, and IL-17 were assessed by using real-time polymerase chain reaction. In the experimental group, at 21-days post-MTA-Se sealing, the mRNA levels of TNF-α and IL-10 were upregulated compared with those in the control group (p < 0.05). Futher assessment revealed basal mRNA expression levels of IL-1α, IFN-γ, RANK, RANKL, IL-17A, IL-4, and TGF-β, over long experimental times, in both the experimental and control groups (p > 0.05). In conclusion, MTA+Se sealing favoured increased expression of IL-10 and TNF-α at later time points (day 21).

Perfurações experimentais de furca tratadas com MTA acrescido de selênio: análise da resposta imune / Experimental furcal perforation treated with mineral trioxide aggregate plus selenium: immune response

A perfuração de furca é uma comunicação mecânica ou patológica entre o sistema de canais radiculares e a superfície externa do dente, permitindo contaminação bacteriana do tecido periodontal e consequente inflamação e perda do tecido de suporte. Atualmente, o MTA (Agregado de trióxido mineral) é o material mais indicado no tratamento dessas perfurações, por ser biocompatível e apresentar bom selamento. A literatura atual relata a capacidade do selênio em inibir crescimento bacteriano, alterar o metabolismo ósseo e estimular o sistema imunitário. O objetivo deste estudo foi avaliar a resposta imunológica do MTA acrescido de selênio. Neste estudo, induziram-se perfurações experimentais de furca em molares de camundongos isentos de germes. O primeiro molar superior esquerdo teve a furca perfurada e tratada com MTA + Selênio (grupo experimental) e no lado direito a furca foi perfurada e tratada com MTA (grupo controle). Os animais foram sacrificados com 07, 14 e 21 dias após a intervenção sendo 5 animais para cada grupo, (n=5). Os tecidos perirradiculares adjacentes à lesão foram extraídos e macerados, fazendo-se, a seguir, a extração do RNA. As expressões das citocinas TGF-ß, TNF-α, IFN-γ, IL-10, IL.4, RANK, RANKL, IL-1α, IL-17A e HPRT foram investigados por PCR em tempo real. No grupo experimental, após o 21 dias, houve um aumento da expressão de TNF-α e IL-10 em comparação com o grupo controle (p <0,05). A avaliação revelou expressão basal de IL-1α, IFN-γ, RANK, RANKL, IL-17A, IL-4 e TGF-ß nos níveis de mRNA, em ambos os grupos experimental e controle, , em todos os tempos experimentais (p > 0,05). O selamento com MTA + Se favoreceu a expressão da citocinas pró-inflamatórias TNFα na fase tardia de resposta (21o dia) paralelo ao aumento da citocina regulatória IL10 no mesmo período. Concluiu-se que, o aumento destas citocinas no grupo tratado com selênio na fase tardia da resposta, provavelmente, se deveu aos seus efeitos imunoregulatórios.

Furcal perforation is a mechanical or pathological communication between the root canal system and outer surface of the tooth. It may allow bacterial contamination and subsequent periodontal tissue inflammation and loss of supportive tissue. Currently, the MTA (mineral trioxide aggregate) is the most suitable material in the treatment of these perforations to be biocompatible and provide good sealing. The literature reports the selenium's ability to inhibit bacterial growth, alter bone metabolism and stimulate the immune system. The objective of this study was to evaluate the immune response of MTA associated with selenium. In this study, experimental furcal perforations were induced in molar of germ-free mice. The first maxillary left molar had the furcal perforated and treated with MTA / Selenium (experimental group) and the right molar, furcal was perforated and treated with MTA (control group). The animals were killed in 07, 14 and 21 days after the intervention (n = 5). mRNA was extracted from periradicular tissues and the eexpressions of TGF-ß, TNF-α, IFN γ, IL10, IL-4, RANK, RANKL, IL-1α, IL-17A e HPRT were investigated by real time PCR. In the experimental groups, on 21 days post MTA+Se sealing it was observed an upregulation of the mRNA levels of TNF-α and IL-10 compared with the control group (p<0.05). Assessment revealed basal expression of IL-1α, IFN-γ, RANK, RANKL, IL17A,IL-4 and TGF-ß gene expression all long of the experimental times, in both groups treated with MTA or MTA+Se (p>0.05). The MTA+Se sealing favored the expression of TNF-α and IL-10 in the later phase of response (21th day). The increase of these cytokines was probably due to immunoregulation of Se levels.