Radiographic and micro-computed tomography classification of root canal morphology and dentin thickness of mandibular incisors.

CONTEXT: Root canal anatomy is evaluated using different methodologies. AIMS: The aim of this study is to evaluate and classify root canal morphology and dentin thicknesses (DT), comparing radiographic and micro-computed tomography (CT) analysis. MATERIALS AND METHODS: Canal diameter and DT of mandibular incisors (n = 520) were evaluated using digital radiographs in buccolingual (BL) and mesiodistal (MD) directions. The diameter ratio (DR) BL/MD was classified: flattened (FL, DR >4); oval (OV, 2≤ DR ≥4); rounded (RN, 1.1< DR >2); round (RO, 0.9≤ DR ≥1.1); and with BL flatness (BL, DR <0.9). OV (n = 110) were subjected to micro-CT. DT and DR were evaluated at 3, 6, and 9 mm. ANOVA, Tukey, and paired Wilcoxon tests (P < 0.05) were used. RESULTS: Radiographic classification was 23.3% FL, 41.3% OV, 27.3% RN, 4.5% RO, and 3.6% BL. DT was similar. Radiographic DT at 3 and 9 mm was greater than micro-CT (P < 0.05) and was similar at 6 mm (P > 0.05). DR differed between the analyses. Oval canals were predominant at all levels radiographically and at 9 and 6 mm in micro-CT analysis, with greater variation at 3 mm. CONCLUSION: Oval root canals are predominant in mandibular incisors at 9 mm. Radiographic DT is larger than observed in micro-CT at 3 and 9 mm, and the classification differed in each root level. The classification at 9 mm is indicated.

Antimicrobial activity of root canal irrigants associated with cetrimide against biofilm and planktonic Enterococcus faecalis.

AIM: To evaluate the antibacterial activity of sodium hypochlorite (NaOCl) and chlorhexidine (CHX) alone or associated with cetrimide (CTR), and QMiX against biofilm and planktonic Enterococcus faecalis (E. faecalis) [American type culture collection (ATCC) 29212]. MATERIALS AND METHODS: The solutions 2.5% NaOCl, 2.5% NaOCl + 0.2% CTR, 2% CHX, 2% CHX + 0.2% CTR, 0.2% CTR, and QMiX were evaluated. E. faecalis biofilms were induced for 14 days on bovine dentin blocks. The irrigants were evaluated after contact with E. faecalis suspension and biofilm for 1 and 3 minutes. After that, serial decimal dilutions were made and plated on tryptic soy agar (TSA) medium. Plates were incubated for 24 hours at 37°C and the colony-forming unit (CFU) 1 ml was determined. Data were subjected to ANOVA and Tukey's tests at 5% significance. RESULTS: All microorganisms were eliminated by direct contact of the irrigants with planktonic cells. Only NaOCl and NaOCl + CTR were able to completely eliminate the microorganisms by direct contact with E. faecalis biofilm. CHX presented effectiveness similar to CHX + CTR CTR, and QMiX after 1 minute of contact and similar to NaOCl and NaOCl + CTR after 3 minutes (p > 0.05), but was unable to completely eliminate the microorganisms. CTR and QMiX did not differ from each other. CONCLUSION: CTR addition to CHX and NaOCl solutions did not improve the antimicrobial activity against biofilm. All evaluated irrigants and associations presented activity against planktonic E. faecalis. Only NaOCl and NaOCl + CTR eliminated biofilm after 1 and 3 minutes of direct contact.

Use of nanoparticulate zinc oxide as intracanal medication in endodontics: pH and antimicrobial activity.

The aim of this study was to evaluate the pH and antimicrobial activity of micro or nanoparticulate zinc oxide (ZnO) pastes with or without calcium hydroxide (CH). The following medications were evaluated: microparticulate ZnO + polyethylene glycol (PEG) 400; nanoparticulate ZnO + PEG 400; PEG 400; CH + microparticulate ZnO + PEG 400 and CH + nanoparticulate ZnO + PEG 400. The pH was assessed between 12 hours and 28 days, using a digital pH meter. The antimicrobial activity against Enterococcus faecalis (ATCC-9212), Candida albicans (ATCC-10231), Pseudomonas aeruginosa (ATCC-27853), Staphylococcus aureus (ATCC-6538) and Kocuria rhizophila (ATCC-9341) was determined in triplicate using agar diffusion test. The results were submitted to Kruskal-Wallis/Dunn and ANOVA/Tukey tests with 5% significance. The highest pH values were found for CH+ZnO, with higher values for nanoparticulate ZnO after 12 hours and 21 days (p < 0.05). CH+ZnO medication promoted higher growth inhibition against P. aeruginosa and lower against E. faecalis. Calcium hydroxide pastes have higher pH and antimicrobial activity when associated with either micro- or nanoparticulate zinc oxide.

Use of nanoparticulate zinc oxide as intracanal medication in endodontics: pH and antimicrobial activity. / Use of nanoparticulate zinc oxide as intracanal medication in endodontics: pH and antimicrobial activity.

The aim of this study was to evaluate the pH and antimicrobial activity of micro or nanoparticulate zinc oxide (ZnO) pastes with or without calcium hydroxide (CH). The following medications were evaluated: microparticulate ZnO + polyethylene glycol (PEG) 400; nanoparticulate ZnO + PEG 400; PEG 400; CH + microparticulate ZnO + PEG 400 and CH + nanoparticulate ZnO + PEG 400. The pH was assessed between 12 hours and 28 days, using a digital pH meter. The antimicrobial activity against Enterococcus faecalis (ATCC-9212), Candida albicans (ATCC-10231), Pseudomonas aeruginosa (ATCC-27853), Staphylococcus aureus (ATCC-6538) and Kocuria rhizophila (ATCC-9341) was determined in triplicate using agar diffusion test. The results were submitted to Kruskal-Wallis/Dunn and ANOVA/Tukey tests with 5

significance. The highest pH values were found for CH+ZnO, with higher values for nanoparticulate ZnO after 12 hours and 21 days (p < 0.05). CH+ZnO medication promoted higher growth inhibition against P. aeruginosa and lower against E. faecalis. Calcium hydroxide pastes have higher pH and antimicrobial activity when associated with either micro- or nanoparticulate zinc oxide.

Ação antibacteriana da cetramida associada às solucões irrigadoras sobre Enterococcus Faecalis / Antibacterial action of cetrimide associated irrigants solutions on Enterococcus faecalis

O objetivo do estudo foi avaliar a ação das soluções de hipoclorito de sódio e clorexidina associadas à cetramida e do QMiX, produto comercial que combina clorexidina, EDTA e cetramida, sobre Enterococcus faecalis (ATCC 29212) em fase planctônica e biofilme. As soluções avaliadas foram: G1: Hipoclorito de sódio (NaOCl) a 2,5%; G2: NaOCl a 2,5% + cetramida (CTR) a 0,2%; G3: Clorexidina (CLX) a 2%; G4: CLX a 2% + CTR a 0,2%; G5: CTR a 0,2%; G6: QMiX. Como controle negativo foi utilizada solução salina. O estudo foi dividido em dois capítulos. No capítulo 1, foi realizada a avaliação da atividade antibacteriana sobre os micro-organismos em fase planctônica e biofilme. Para o contato direto com E. faecalis em fase planctônica, 50 µl da suspensão bacteriana foram colocados em tubos contendo 1,45 mL de cada solução irrigadora ou associações e, após os períodos de 1 e 3 minutos foram utilizadas soluções neutralizantes da ação antimicrobiana dos irrigantes. Em seguida, foi realizada diluição decimal seriada e plaqueamento em meio Tryptic Soy agar (TSa). Para a indução dos biofilmes foram utilizados blocos de dentina bovina como substrato no período de 14 dias. Os biofilmes foram colocados em contato com as soluções avaliadas, e transferidos para tubos de ensaio contendo soluções neutralizantes. Após agitação por 60 segundos para a suspensão das células remanescentes, foi realizada diluição decimal seriada e plaqueamento em TSa em triplicata. A incubação foi realizada em microaerofilia a 37°C por 24 horas e a análise efetuada por meio da contagem de UFC mL-1 . Os resultados foram submetidos aos testes ANOVA e Tukey, com nível de significância de 5%. Todas as soluções irrigadoras e associações avaliadas eliminaram completamente os micro-organismos em fase planctônica. Sobre biofilme, somente NaOCl e NaOCl+CTR apresentaram 100% de eliminação bacteriana. A CLX mostrou ação semelhante à CLX+CTR, CTR e QMiX após 1 min (p>0,05). A CTR e QMiX foram similares após 3 min. CLX e CLX+CTR mostraram atividade antibiofilme comparável à NaOCl e NaOCl+CTR após 3 min, no entanto não foram capazes de eliminar os micro-organismos do biofilme. Conclui-se que a associação da CTR às soluções irrigadoras não altera a efetividade antibiofilme. No Capítulo 2, foi realizada a análise da atividadade antibiofilme das soluções irrigadoras e associações por microscopia confocal de varredura a laser. Os biofilmes de 14 dias foram colocados em contato direto com as soluções irrigadoras por 1 minuto, e após o lavagem em soluções neutralizantes, foram corados com Live/Dead® BacLight, sendo levados para a análise em microscópio confocal de varredura a laser. As imagens foram avaliadas no software BioImage_L, sendo analisados biovolume total (µm3), biovolume verde (µm3) e percentual de cobertura do substrato. Os dados foram submetidos ao teste não paramétrico de Kruskal-Wallis e de Dunn, com nível de significância de 5%. Os menores valores de biovolume total e verde foram apresentados por NaOCl e NaOCl+CTR (p<0,05). CTR e QMiX mostraram valores intermediários para o biovolume verde após sua utilização, com atividade superior à CLX e CLX+CTR (p<0,05). NaOCl e NaOCl+CTR mostraram maior capacidade de remoção de microorganismos e limpeza do substrato. QMiX não proporcionou elimiminação bacteriana sobre a dentina, com resultados intermediários. Conclui-se que NaOCl a 2,5% e NaOCl+CTR a 0,2% são os únicos irrigantes com maior atuação sobre a viabilidade, arquitetura e eliminação de biofilme

The aim of this study was to evaluate the action of conventional endodontic solutions such as sodium hypochlorite and chlorhexidine associated with cetrimide and QMiX, a commercial product composed by chlorhexidine, EDTA and cetrimide, on biofilm and planktonic phase of Enterococcus faecalis (ATCC 29212). The evaluated solutions were: G1: 2.5% Sodium Hypochlorite (NaOCl); G2: 2.5% NaOCl + 0.2% cetrimide (CTR); G3: 2% Chlorhexidine (CLX) 2%; G4: 2% CLX + 0.2% CTR; G5: 0.2% CTR; G6: QMiX. Saline solution was used as negative control. The study was divided into two chapters. In Chapter 1, the antibacterial activity of the solutions on microorganisms in planktonic phase and biofilm was evaluated. For direct contact with E. faecalis in planktonic phase, 50 µL of bacterial suspension were placed in tubes containing 1.45 mL of each irrigation solution or associations and after 1 and 3 minutes, neutralizing solutions were used to stop of the antimicrobial action of endodontic solutions. Decimal serial dilutions were performed and the suspensions were plated in Tryptic Soy agar medium (TSa). Dentin bovine blocks were used as substrate for induction of biofilms for 14 days. The biofilms were placed in contact with the solutions evaluated and transferred to test tubes containing neutralizing solution. After agitation for 60 seconds to suspend the remaining cells, decimal serial dilutions were performed and the suspensions were cultivated in triplicate on TSA plates. The incubation was held in microaerophilic at 37 ° C for 24 hours and the analysis was performed by counting CFU mL-1. The results were submitted to ANOVA and Tukey test, with significance level of 5%. All irrigating solutions and associations evaluated completely eradicated the microorganisms in planktonic phase. On biofilm, only NaOCl and NaOCl+CTR showed 100%- of bacterial elimination. CLX showed similar activity to CLX+CTR, CTR and QMiX after 1 min (p>0.05). CTR were similar QMiX after 3 min. CLX and CLX+CTR presented similar antibiofilm activity to NaOCl and NaOCl + CTR after 3 min, however, these solutions were not able to eradicated micro-organisms of the biofilm. It is concluded that the association of the CTR does not alter the antibiofilm effectiveness of endodontic solutions. In Chapter 2, the antibiofilm activity of endodontic solutions and associations was analysed by confocal laser scanning. Biofilms were cultivated for 14 days and then placed in direct contact with the irrigating solutions for 1 minute, after this period they were washed in neutralizing solutions and stained with dye Live/Dead® BacLight for analysis under a confocal laser scanning microscope. The images were evaluated using the software BioImage_L and the parameters total biovolume (µm 3), green biovolume (µm 3) and percent substratum coverage were evaluated. The data were were analysed to nonparametric Kruskal-Wallis and Dunn, with a significance level of 5%. The lowest values of total biovolume and green biovolume were presented by NaOCl and NaOCl+CTR (p<0.05). CTR and QMiX showed intermediate values for the green biovolume after use and higher activity than CLX and CLX+CTR (p<0.05). NaOCl and NaOCl+CTR showed better microorganism's removal capacity and substrate cleaning. QMiX did provided bacterial elimination on dentin, with intermediate results. It is concluded that 2.5% NaOCl and NaOCl+ 0.2% CTR are the only solutions with higher acting on the viability, architecture and removal of biofilm

Ação solvente do salicilato de metila sobre Resilon e guta-percha / Solvent action of methyl salicylate on Resilon and gutta-percha

Objetivo: O objetivo deste estudo foi avaliar a ação do salicilato de metila na dissolução de Resilon e guta-percha. Material e método: Dez discos de Resilon, guta-percha (Alpha) e guta-percha (ProTaper) foram preparados (10 mm de diâmetro × 1 mm de espessura) e mantidos a 37 °C por 48 horas. Cada amostra foi pesada em uma balança de precisão, determinando a massa inicial. Os espécimes foram imersos em salicilato de metila ou xilol (controle) por 5 minutos, lavados em água por 30 minutos, secos e, posteriormente, pesados em intervalos de 24 horas, até a estabilização da massa (massa final). A capacidade solvente foi expressa pela diferença entre a massa final e a inicial. Os dados foram submetidos à análise de variância e teste de Tukey, com nível de significância de 5%. Resultado: Os resultados mostraram que o salicilato de metila foi mais efetivo sobre o Resilon do que sobre a guta-percha (p <0,05). A capacidade solvente do salicilato de metila foi semelhante à do xilol sobre o Resilon (p >0,05). O xilol mostrou melhor atuação sobre a guta-percha em comparação ao salicilato de metila (p < 0,05). Conclusão: Concluiu-se que o salicilato de metila não apresenta atuação solvente sobre guta-percha, sendo eficaz na dissolução do Resilon. O salicilato de metila demonstra ser alternativa ao uso do xilol durante o retratamento endodôntico de dentes obturados com Resilon.

Objective: The aim of this study was to evaluate the action of methyl salicylate in dissolving Resilon and gutta-percha. Material and method: Ten discs of Resilon, Alpha gutta-percha and ProTaper gutta-percha were prepared (10 mm diameter × 1 mm thick) and kept at 37 °C for 48 hours. Each sample was weighed in a balance of accuracy determining the initial mass. The specimens were immersed in methyl salicylate or xylene (control) for 5  minutes, rinsed in water for 30 minutes, dried and subsequently weighed in 24 hours intervals until the stabilization of weight (final mass). The solvent capacity was expressed by the difference between the final and initial mass. The data were analyzed by using ANOVA and Tukey test with significance level of 5%. Result: The results showed that the methyl salicylate was more effective on Resilon than on gutta-percha (p < 0.05). Methyl salicylate and xylene had similar solvent action on Resilon (p > 0.05). The xylene showed better performance on gutta-percha than methyl salicylate (p < 0.05). Conclusion: It was concluded that methyl salicylate did not show solvent action on gutta-percha, however it showed effectiveness in dissolution of Resilon. Thus methyl salicylate can be a possible alternative to the use of xylene during endodontic retreatment of teeth obturated with Resilon.

Avaliação do pH, da solubilidade e da infiltraçãomarginal em retrobturações com o Sealer 26®puro ou acrescido de iodofórmio / Evaluation of pH, solubility and marginalleakage in retrobturation cases using Sealer 26®alone or with iodoform

Introdução: O cimento Sealer 26® contém resina epóxi associada aohidróxido de cálcio, apresentando menor radiopacidade que algunscimentos endodônticos. Com o intuito de melhorar essa propriedade,tem-se agregado iodofórmio ao pó do cimento. Entretanto, aoexecutar tal procedimento, desconhecem-se as possíveis alteraçõesnas propriedades físicas e químicas do material. Objetivo: Avaliar acapacidade de selamento marginal apical, a solubilidade e o pH doSealer 26® puro ou acrescido de iodofórmio em diversas proporções.Material e métodos: Foram manipuladas e submetidas ao teste desolubilidade três associações experimentais de Sealer 26®, puroou acrescido de iodofórmio. Paralelamente, as combinações foraminseridas em tubos de polietileno e imersas em água destilada, e opH das soluções foi avaliado nos períodos de 24 horas e 7 dias. Emseguida, 40 raízes de incisivos inferiores extraídos, subdivididosem quatro grupos de dez espécimes cada, foram retrobturados comuma das misturas anteriormente descritas. Imergiram-se as raízesem Rhodamine B, sob vácuo, por 72 horas. Concluída a imersão,os espécimes foram desgastados longitudinalmente, os fragmentosradiculares fotografados, as imagens digitalizadas e a infiltração apicalmedida pelo programa Image Tool. Os dados obtidos foram submetidosa análise estatística, com nível de significância de 5%. Resultados:Os testes de infiltração e solubilidade não demonstraram diferençasentre os grupos experimentais (p > 0,05). A análise do pH apresentoudiferença apenas no período de 24 horas entre o grupo do Sealer 26®puro e o grupo com 1,1 g de iodofórmio (p < 0,05). Conclusão: Aadição de iodofórmio ao Sealer 26®, nas proporções descritas, nãoalterou as propriedades de selamento marginal apical, a solubilidadenem o pH do cimento original

Introduction: Sealer 26® cement contains bisphenol epoxy resinassociated with calcium hydroxide, presenting smaller radiopacity thanother endodontic cements. Aiming to improve this property, iodoformhas been added in its composition. However, this addition?s possiblechanges in physical and chemical properties still need to be studied.Objective: To evaluate the apical sealing ability, solubility, and pH ofSealer 26® alone or with iodoform, at several proportions. Material andmethods: Three experimental mixtures of Sealer 26®, alone or withiodoform, were prepared and subjected to solubility test. Additionally,these combinations were inserted into polyethylene tubes and immersedin distilled water, and, their pH was evaluated after 24-h and 7-dayperiods. Subsequently, forty roots of extracted lower incisors subdividedinto four groups of 10 specimens each, were retrograde filled with oneof the previously described mixtures and gutta-percha points. The rootswere immersed in Rhodamine B, under vacuum, for 72 hours. Afterthis period, the specimens were longitudinally sectioned, root fragmentsphotographed, these images scanned, and apical infiltration measuredby Image tool software. The obtained data were subjected to statisticalanalysis, at a significance level of 5%. Results: Marginal leakage andsolubility tests did not show any difference among the experimentalgroups (p > 0.05). pH analysis was only statistically different at 24-h period and between Sealer 26® alone and 1.1g iodoform group(p < 0.05). Conclusion: The presence of iodoform in Sealer 26®, at theused proportions, did not alter the solubility, apical marginal leakageand pH properties of the original cement.

Capacidade de termoplastifcação da guta-percha com diferentes conicidades / Thermoplasticity capacity of gutta-percha with different tapers

Objetivo: O objetivo deste estudo foi avaliar a capacidade de termoplastificação da guta-percha com diferentes conicidades utilizadas na obturação de canais radiculares: Dentsply convencional (Dentsply Ind. e Com. Ltda., Petrópolis - RJ, Brasil), Dentsply 0,04, (Dentsply Ind. e Com. Ltda., Petrópolis-RJ, Brasil), Antaeos 0,04 (VDW GmbH, München, Alemanha), Protaper (Dentsply Ind. e Com. Ltda., Petrópolis-RJ, Brasil) e Alfa 0,06 (VDW GmbH, München, Alemanha). Material e método: Corpos de prova de cada material (n = 10) foram confeccionados após aquecimento. Depois de 24 horas, foram novamente aquecidos à temperatura de 70 °C e posicionados entre duas placas de vidro, sendo submetidos a uma compressão de 5 kg por 2 minutos. A imagem digitalizada dos grupos antes e depois da compressão foi analisada no software Image Tool (UTHSCSA Image Tool for Windows version 3.0, San Antonio, TX, USA). A capacidade de escoamento dos diferentes materiais foi determinada pela diferença entre as áreas inicial e final da cada espécime. Os resultados obtidos foram submetidos ao teste ANOVA e Tukey com nível de significância de 5%. Resultado: Dentre os materiais analisados, os cones de guta-percha Alfa 0,06 e Protaper apresentaram maior termoplastificação quando comparados aos demais (p < 0,05). O grupo Dentsply apresentou termoplasticidade intermediária, enquanto que os grupos Dentsply 0,04 e Antaeos 0,04 apresentaram menor termoplastificação após aquecimento (p > 0,05). Conclusão: Os cones de guta-percha apresentam diferentes propriedades de termoplastificação, sendo esta característica importante na seleção das técnicas de obturação termoplásticas.

Objective: The objective of this study was to evaluate the thermoplasticity of the gutta-percha cones used for root canal obturation: Dentsply convencional (Dentsply Ind. e Com., Petrópolis, RJ, Brazil), Dentsply 0.04, (Dentsply Ind. e Com., Petrópolis, RJ, Brazil), Antaeos 0.04 (VDW GmbH, Munich, Germany), ProTaper (Dentsply Ind. e Com., Petrópolis, RJ, Brazil) and Alfa 0.06 (VDW GmbH, Munich, Germany). Material and method: Specimens of each material (n = 10) were prepared after heating. After 24 hours were again heated to 70 °C and placed between two glass plates and subjected to a compression of 5 kg for 2 minutes. The scanned image of the groups before and after the compression was analyzed with the software Image Tool (UTHSCSA Image Tool for Windows version 3.0, San Antonio, TX, USA). The flow capacity of the different materials was determined by the difference between the initial and final area of each specimen. The results were submitted to ANOVA and Tukey test with significance level of 5%. Result: Among the material evaluated, the gutta-percha cones Alpha 0.06 and ProTaper presented more thermoplasticity than other groups (p < 0.05). The Dentsply gutta-percha presented thermoplasticity intermediate. The groups Dentsply 0.04 and 0.04 showed lower thermoplasticity after heating (p > 0.05). Conclusion: The gutta-percha present different property of thermoplasticity, which is important to selection of thermoplastic obturation techniques.

Deslocamento axial de fluido em capilar de vidro, após a reação intracoronária de diversos agentes clareadores / Axial displacement of fluid in glass capillary after intracoronary reaction of several bleaching agents

Introdução e objetivo: Buscou-se quantificar, indiretamente, a liberaçãode oxigênio após a reação química intracoronária, por deslocamentoaxial de fluido em capilares de vidro, adaptados em coroas dentárias.Material e métodos: Coroas bovinas foram acessadas, e foi executadoo tampão cervical e posicionado um capilar de vidro na face externavestibular, contendo um veículo oleoso. Na sequência, foram preparadasquatro associações de clareadores e colocadas em seu interior: G1? perborato de sódio e peróxido de hidrogênio a 3%; G2 ? perborato de sódio e água; G3 ? associação de percarbonato de sódio e peróxidode hidrogênio a 3%; G4 ? associação de percarbonato de sódio eágua destilada. Após serem mantidas por 24 horas, quantificou-se odeslocamento axial do fluido, interpretado como liberação de oxigêniopela reação química. Resultados: Os resultados mostraram umatendência das associações com o peróxido de hidrogênio em promovermaior liberação de oxigênio. Entretanto não houve diferença entre operborato de sódio e o percarbonato de sódio (p > 0,05). Conclusão:Os grupos experimentais não demonstraram diferenças entre si duranteas 24 horas de reação química.

Objective: To indirectly quantify the release of oxygen after intracoronarychemical reaction, by axial displacement of fluid in glass capillariesarranged in dental crowns. Material and methods: Bovine crownswere accessed, the cervical plug was executed and a glass capillarywas placed in the vestibular external face, containing an oily vehicle.Following that, four associations of bleaching were prepared and placedin its interior: G1 ? sodium perborate and hydrogen peroxide 3%; G2? sodium perborate and water, G3 ? sodium percarbonate and hydrogenperoxide 3%; G4 ? sodium percarbonate and distilled water. After beingkept for 24 hours, the axial displacement of the fluid was quantifiedand interpreted as the release of oxygen by the chemical reaction.Results: The results showed a trend of the associations with hydrogenperoxide to promote the release of more oxygen. However, there wasno difference between sodium perborate and sodium percarbonate(p > 0.05). Conclusion: The experimental groups showed no differencesbetween them during the 24 hours of chemical reaction.