Influence of some chemical characteristics on the use of chlorine-containing solutions as root canal irrigants

• Main Author: Rossi-fedele, Giampiero
• Other Authors: Figueiredo, Jos? Antonio Poli de
• Format: Others
• Language: English
• Published: Pontif?cia Universidade Cat?lica do Rio Grande do Sul 2015
• Subjects: ODONTOLOGIA; ENDODONTIA; PERIODONTIA; TRATAMENTO DE CANAL RADICULAR; CNPQ::CIENCIAS DA SAUDE::ODONTOLOGIA
• Online Access: http://tede2.pucrs.br/tede2/handle/tede/1190

Made available in DSpace on 2015-04-14T13:30:18Z (GMT). No. of bitstreams: 1 445196.pdf: 1621776 bytes, checksum: e673407b63b49acb88ac4cdca25478b3 (MD5) Previous issue date: 2013-01-15 === Aim : the goal of the present investigation was to look into chemical interactions and characteristics, other than chlorine concentration, and their effect on the overall performance of chlorine-containing root canal irrigants. Methodology : Three different searches were performed in the Medline electronic database, with the purpose of identifying publications that: (a) reviewed the influence of pH changes on the efficacy of chlorine-containing endodontic irrigating solutions; (b) studied unwanted chemical interactions between sodium hypochlorite (NaOCl), chlorhexidine (CHX), EDTA and Citric acid; (c) compared NaOCl alone and NaOCl modified with the addition of a surface-active agent in endodontics. A hand search of articles published online, and appearing in the reference list of the articles included (for search c only), was further performed, using the same search criteria as the electronic search. Four investigations were carried out: (a) to evaluate the antimicrobial effect of Sterilox and sodium hypochlorite against Enterococcus faecalis in a bovine root canal model; (b) to evaluate the bovine pulp tissue dissolution ability of Sterilox, HealOzone, and 0.5% sodium hypochlorite, used alone or in combination; (c) to understand the effect of storage conditions on Sterilox s stability. Eight bottles (four completely full, four half-full) of freshly prepared solution were divided into four groups and subsequently stored by being either exposed to or protected from sunlight; (d) to evaluate whether the immersion of CHX impregnated guttapercha points in chlorine-containing endodontic irrigants causes colour changes and precipitate formation, eighty-one CHX medicated points were immersed in microtubes, containing the following solutions: 0.5 and 5.25% NaOCl or Aquatine (Sterilox). The samples were visually assessed by two independent observers at regular intervals over three weeks to detect colour changes and precipitate formation. Results : The searches identified: for topic a: 1304 publications, 20 fulfilled the inclusion/exclusion criteria; for topic b: 1285 publications, 19 fulfilled the inclusion/exclusion criteria; for topic c: 302 publications 11 fulfilled the inclusion/exclusion criteria. For investigation a: statistically significant differences between the groups exposed to sunlight and non-exposed groups (p <0.001) were found, whilst the presence of air did not affect the chlorine decomposition in the bottles. For investigation b: the groups containing 5.25% NaOCl started to produce a visible precipitate after fourteen days (16.48 ? 0.98) for the impregnated points; no other test group presented with changes. Conclusions : Regarding investigation (a), on antimicrobial efficacy, NaOCl appears to be the best preparation amongst chlorine-containing irrigants; this can be enhanced by reducing its pH. Interactions with chelating agents can reduce this action, and there is no clear evidence regarding the effect of surface-tension modification. Investigation (b) on tissue dissolution ability showed that NaOCl is the only chlorine-containing solution with a clinically relevant action. Sodium hypochlorite dissolution ability may be speeded up with the adjunct use of ozone. The literature reviews also pointed out that interaction with chelators reduce this ability, whilst the surface tension of the preparations has no influence. By mixing NaOCl and CHX in liquid or gel forms, a precipitate is formed; this is likely to contain a cancerogenic substance. Investigation (c) showed that Sterilox chlorine concentration is stable for a twoweek period if protected from direct sunlight; if exposed to sunlight the degradation process started after 4 days. Investigation (d) allowed stating that the placement of impregnated guttapercha points in 5.25% NaOCl for a two-week period caused the formation of a precipitate in the experimental conditions of this study. === Objetivo : este estudo buscou avaliar as intera??es e caracter?sticas qu?micas, al?m da concentra??o de cloro, que afetam o desempenho das solu??es irrigadoras contendo cloro na desinfec??o dos canais radiculares. Metodologia : Sete estudos foram realizados, sendo tr?s de revis?o de literature e quarto trabalhos experimentais. (1) revisou a influ?ncia das modifica??es de pH na efic?cia das solu??es irrigadoras contend cloro. (2) estudou as intera??es qu?micas indesej?veis entre hipoclorito de s?dio e clorexidina, EDTA e ?cido c?trico. (3) comparou o hipoclorito de s?dio usado isoladamente e adicionado com agente surfactante. Uma busca manual foi realizada dos artigos dispon?veis online, quando necess?rio, utilizando o mesmo crit?rio da busca eletr?nica. (4) avaliou a atividade antimicrobiana do Sterilox e do hipoclorito de s?dio em dentes bovinos infectados por Enterococcus faecalis. (5) avaliou a capacidade de dissolu??o de tecido pulpar bovino do Sterilox, do HealOzone e do hipoclorito de s?dio a 0,5%, tanto em uso isolado como em combina??o. (6) Buscou compreender o efeito da luz solar na estabilidade do Sterilox comparado ao hipoclorito de s?dio. (7) avaliou o efeito da imers?o, em hipoclorito de s?dio a 0,5% e a 5,25%, de cones de guta-percha impregnados com clorexidina na modifica??o de cor e na forma??o de precipitado em tubos de Eppendorf transparentes. As metodologias espec?ficas de cada estudo encontram-se nas publica??es. Resultados : Os estudos de revis?o mostraram que o pH pode interferir positivamente na a??o antimicrobiana e negativamente na capacidade de dissolu??o tecidual das solu??es contendo cloro (1). Al?m disso, intera??es com as subst?ncias contendo cloro podem afetar positiva ou negativamente nas propriedades dessas subst?ncias (2). O uso de surfactante ainda necessita maiores estudos para avaliar o potencial no favorecimento da a??o dessas subst?ncias no sistema de canais radiculares (3). Em rela??o aos estudos experimentais, foram encontradas os seguintes achados: o Sterilox tem atividade antimicrobiana, mas estatisticamente inferior ao hipoclorito de s?dio (4); o Sterilox n?o tem capacidade de dissolver tecido pulpar, mas a velocidade de dissolu??o do hipoclorito de s?dio pode ser aumentada com o uso do oz?nio (5); a luz solar interfere no tempo de estabilidade do Sterilox (6); precipitados s?o formados depois da imers?o em hipoclorito de s?dio por 14 dias, tanto em cones sem como com clorexidina, embora a clorexidina propiciasse precipitados bastante expressivos (7). Conclus?es : Do ponto de vista de a??o antimicrobiana, o hipoclorito de s?dio parece ser a melhor solu??o irrigadora. Sua a??o pode ser aumentada com a diminui??o do seu pH. As intera??es com outras subst?ncias podem reduzir a a??o do hipoclorito de s?dio, e o efeito de um surfactante necessita maiores estudos para avaliar seu efeito. O hipoclorito de s?dio ? a ?nica subst?ncia contendo cloro que tem a??o relevante na dissolu??o de tecido pulpar, mas sua atividade pode ser potencializada por oz?nio. A mistura de hipoclorito de s?dio com clorexidina forma precipitados e a libera??o de subst?ncia potencialmente cancerog?nica. Este precipitado pode ocorrer inclusive em cones de guta-percha impregnados com clorexidina quando em contato com o hipoclorito de s?dio. A concentra??o de cloro no Sterilox permanence est?vel por 14 dias se estiver protegida da luz solar.