Root canal irrigation: physicochemical and biological properties of calcium hypochlorite and effects of the GentleWave system in endodontic treatment
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2022-09-05
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Universidade Estadual Paulista (Unesp)
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Parte 1: Na publicação 1, o objetivo foi avaliar as propriedades físico-químicas e a penetrabilidade nos túbulos dentinários do hipoclorito de cálcio [Ca(OCl)2] a 2,5% associado aos surfactantes cloreto de benzalcônio (BAK), cetrimida (CTR), tween 80 (T80) e triton X-100 (TR100), na concentração micelar crítica (CMC), em comparação ao hipoclorito de sódio (NaOCl) a 2,5%. Foram avaliados tensão superficial, pH, conteúdo de cloro livre (FAC), íons cálcio livres (Ca2+) e a penetrabilidade nos túbulos dentinários. A adição de surfactantes reduziu a tensão superficial das soluções (p<0,05), e não alterou o pH e o FAC (p>0,05). Os surfactantes, principalmente BAK, aumentaram a disponibilidade de Ca2+ em Ca(OCl)2 (p<0,05). Ca(OCl)2 apresentou menor penetrabilidade nos túbulos dentinários que NaOCl (p<0,05) e a adição de surfactantes àquele não aumentou a sua penetrabilidade nos túbulos dentinários. Na publicação 2, o objetivo foi avaliar o mecanismo de citotoxicidade da solução de Ca(OCl)2 em fibroblastos L929 e o seu efeito na biologia de osteoblastos-like (Saos-2), em comparação com NaOCl. Fibroblastos L929, expostos a Ca(OCl)2 e NaOCl, foram avaliados quanto ao metabolismo celular, integridade dos lisossomos, tipo de morte, alterações no citoesqueleto e na ultraestrutura. O efeito das soluções sobre a atividade da fosfatase alcalina (ALP) foi determinada em Saos-2. O Ca(OCl)2 promoveu maior viabilidade celular e menor porcentagem de apoptose e necrose do que o NaOCl (p<0,05). Ca(OCl)2 e NaOCl diminuíram o metabolismo celular e a integridade dos lisossomos, induziram ruptura de microtúbulos e filamentos de actina, promoveram alterações do retículo endoplasmático rugoso e nas cristas mitocondriais, e não induziram a atividade da ALP. Concluiu-se que, embora a adição de surfactantes ao Ca(OCl)2 não aumentou a sua penetrabilidade nos túbulos dentinários, eles promoveram menor tensão superficial, sem alterações nos valores de pH e FAC, além de maior disponibilidade de Ca2+ na solução. Adicionalmente, NaOCl e Ca(OCl)2 apresentaram o mesmo mecanismo de citotoxicidade e não induziram atividade de ALP, porém, Ca(OCl)2 foi menos citotóxico que NaOCl. Parte 2: Na publicação 3, o objetivo foi descrever, por meio de revisão de literatura, os efeitos do sistema GentleWave (GW) no tratamento endodôntico. GW mostrou resultados in vitro semelhantes ou melhores que a irrigação utrassônica passiva (PUI) sob diferentes aspectos. Clinicamente, embora GW tenha mostrado resultados promissores, ainda são necessários mais estudos. Na publicação 4, o objetivo foi avaliar a eficácia de remoção de biofilme multiespécie do GW e PUI. Molares inferiores humanos com configuração tipo II de Vertucci na raiz mesial foram inoculados com placa dental e incubados. As raízes mesiais foram instrumentadas até 20.06 (V-Taper) para o grupo GW, e até 35.04 (Vortex Blue) para o grupo PUI. Raspas de dentina foram obtidas pré e pós-tratamento para a análise por reação em cadeia da polimerase quantitativa (qPCR) e por sequenciamento do gene rRNA 16S (Next Generation Sequencing - NGS). Não houve diferença na remoção de biofilme entre GW e PUI (p>0,05). Pode-se concluir que mais pesquisas, principalmente clínicas, são necessárias para estabelecer se GW apresenta vantagens sobre outros métodos de irrigação.
Part 1: In publication 1, the aim was to assess the physicochemical properties and the penetration into dentinal tubules of calcium hypochlorite [Ca(OCl)2] at 2.5% associated with the surfactants benzalkonium chloride (BAK), cetrimide ( CTR), tween 80 (T80) and triton X-100 (TR100), at critical micellar concentration (CMC), compared to sodium hypochlorite (NaOCl) at 2.5%. Surface tension, pH, free available chlorine (FAC), free calcium ions (Ca2+) and penetration into dentinal tubules were evaluated. The addition of surfactants reduced the surface tension of the solutions (p<0.05), and did not change the pH and FAC (p>0.05). Surfactants, mainly BAK, increased the Ca2+ availability in Ca(OCl)2 (p<0.05). Ca(OCl)2 showed lower penetration into dentinal tubules than NaOCl (p<0.05) and the addition of surfactants to Ca(OCl)2 did not increase its penetration into dentinal tubules. In publication 2, the aim was to assess the cytotoxicity mechanism of Ca(OCl)2 solution on L929 fibroblasts and its effect on osteoblast-like (Saos-2) biology, compared to NaOCl. Cellular metabolism, lysosome integrity, type of cell death, changes in cytoskeleton and ultrastructure of L929 fibroblasts, exposed to Ca(OCl)2 and NaOCl, were evaluated. The effect of the solutions on alkaline phosphatase (ALP) activity was determined in Saos-2. Ca(OCl)2 promoted higher cell viability and lower percentage of apoptosis and necrosis than NaOCl (p<0.05). Ca(OCl)2 and NaOCl decreased cellular metabolism and lysosome integrity, induced disruption of microtubules and actin filaments, promoted changes in the rough endoplasmic reticulum and mitochondrial cristae, and did not induce ALP activity. It was concluded that, although the addition of surfactants to Ca(OCl)2 did not increase its penetration into dentinal tubules, they promoted lower surface tension, without changes in pH and FAC values, in addition to higher Ca2+ availability. Additionally, NaOCl and Ca(OCl)2 showed the same mechanism of cytotoxicity, and they did not induce ALP activity; however, Ca(OCl)2 was less cytotoxic than NaOCl. Part 2: In publication 3, the aim was to describe, through a literature review, the effects of the GentleWave system (GW) in endodontic treatment. GW showed similar or better in vitro results than passive ultrasonic irrigation (PUI) in different aspects. Clinically, although GW has shown promising results, further studies are still needed. In publication 4, the aim was to assess the effectiveness of multispecies biofilm removal of GW and PUI. Human mandibular molars with Vertucci type II configuration in the mesial roots were inoculated with dental plaque and incubated. Mesial roots were instrumented up to 20.06 (V-Taper) for GW group, and up to 35.04 (Vortex Blue) for PUI group. Dentin shavings were obtained pre- and post-treatment for analysis by quantitative real-time Polymerase Chain Reaction (qPCR) and 16S ribosomal RNA gene sequencing (Next Generation Sequencing - NGS). There was no difference in biofilm removal between GW and PUI (p>0.05). It can be concluded that more research, mainly clinical, is needed to establish whether GW has advantages over other irrigation methods.
Part 1: In publication 1, the aim was to assess the physicochemical properties and the penetration into dentinal tubules of calcium hypochlorite [Ca(OCl)2] at 2.5% associated with the surfactants benzalkonium chloride (BAK), cetrimide ( CTR), tween 80 (T80) and triton X-100 (TR100), at critical micellar concentration (CMC), compared to sodium hypochlorite (NaOCl) at 2.5%. Surface tension, pH, free available chlorine (FAC), free calcium ions (Ca2+) and penetration into dentinal tubules were evaluated. The addition of surfactants reduced the surface tension of the solutions (p<0.05), and did not change the pH and FAC (p>0.05). Surfactants, mainly BAK, increased the Ca2+ availability in Ca(OCl)2 (p<0.05). Ca(OCl)2 showed lower penetration into dentinal tubules than NaOCl (p<0.05) and the addition of surfactants to Ca(OCl)2 did not increase its penetration into dentinal tubules. In publication 2, the aim was to assess the cytotoxicity mechanism of Ca(OCl)2 solution on L929 fibroblasts and its effect on osteoblast-like (Saos-2) biology, compared to NaOCl. Cellular metabolism, lysosome integrity, type of cell death, changes in cytoskeleton and ultrastructure of L929 fibroblasts, exposed to Ca(OCl)2 and NaOCl, were evaluated. The effect of the solutions on alkaline phosphatase (ALP) activity was determined in Saos-2. Ca(OCl)2 promoted higher cell viability and lower percentage of apoptosis and necrosis than NaOCl (p<0.05). Ca(OCl)2 and NaOCl decreased cellular metabolism and lysosome integrity, induced disruption of microtubules and actin filaments, promoted changes in the rough endoplasmic reticulum and mitochondrial cristae, and did not induce ALP activity. It was concluded that, although the addition of surfactants to Ca(OCl)2 did not increase its penetration into dentinal tubules, they promoted lower surface tension, without changes in pH and FAC values, in addition to higher Ca2+ availability. Additionally, NaOCl and Ca(OCl)2 showed the same mechanism of cytotoxicity, and they did not induce ALP activity; however, Ca(OCl)2 was less cytotoxic than NaOCl. Part 2: In publication 3, the aim was to describe, through a literature review, the effects of the GentleWave system (GW) in endodontic treatment. GW showed similar or better in vitro results than passive ultrasonic irrigation (PUI) in different aspects. Clinically, although GW has shown promising results, further studies are still needed. In publication 4, the aim was to assess the effectiveness of multispecies biofilm removal of GW and PUI. Human mandibular molars with Vertucci type II configuration in the mesial roots were inoculated with dental plaque and incubated. Mesial roots were instrumented up to 20.06 (V-Taper) for GW group, and up to 35.04 (Vortex Blue) for PUI group. Dentin shavings were obtained pre- and post-treatment for analysis by quantitative real-time Polymerase Chain Reaction (qPCR) and 16S ribosomal RNA gene sequencing (Next Generation Sequencing - NGS). There was no difference in biofilm removal between GW and PUI (p>0.05). It can be concluded that more research, mainly clinical, is needed to establish whether GW has advantages over other irrigation methods.
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Palavras-chave
Biofilms, Calcium hypochlorite, High-throughput nucleotide sequencing, Surface-active agents, Materials testing