Physicochemical properties and penetration into dentinal tubules of calcium hypochlorite with surfactants

Abstract The aim was to assess the physicochemical properties and the penetration into dentinal tubules of calcium hypochlorite solution [Ca(OCl)2], with or without surfactants. The surfactants benzalkonium chloride, cetrimide, Tween 80 and Triton X-100 were mixed at different concentrations with sodium hypochlorite solution (NaOCl), Ca(OCl)2 and distilled water (control). Once the critical micellar concentration (CMC) of the surfactants in Ca(OCl)2 and NaOCl was determined, pH, free chlorine, surface tension and free calcium ions were evaluated. The penetration into dentinal tubules of NaOCl and Ca(OCl)2, with or without benzalkonium chloride and Triton X-100 [surfactants that promoted the lowest surface tension of Ca(OCl)2], was assessed using human premolars stained with crystal violet. The statistical tests were one-way ANOVA and Tukey's post-test, Kruskal-Wallis and Dunn's post-test, two-way ANOVA and Bonferroni's post-test, and t-test; depending on the assay. The addition of surfactants reduced the surface tension of NaOCl and Ca(OCl)2, and did not alter the pH or the free available chlorine of either solution. The addition of all surfactants increased the availability of free calcium ions in Ca(OCl)2, especially benzalkonium chloride. Ca(OCl)2 exhibited lower penetration into dentinal tubules than NaOCl, and the addition of surfactants did not improve the penetration of Ca(OCl)2, but did increase the penetration of NaOCl. It can be concluded that the addition of surfactants to Ca(OCl)2 did not increase the penetration into dentinal tubules, but it did promote lower surface tension, without changing the pH or free available chlorine values, and higher availability of free calcium ions in Ca(OCl)2.

Resumo O objetivo foi avaliar as propriedades físico-químicas e a penetrabilidade nos túbulos dentinários da solução de hipoclorito de cálcio [Ca(OCl)2], com ou sem surfactantes. Os surfactantes cloreto de benzalcônio, cetrimida, Tween 80 e Triton X-100 foram misturados em diferentes concentrações com a solução de hipoclorito de sódio (NaOCl), Ca(OCl)2 e água destilada (controle). Uma vez determinada a concentração micelar crítica (CMC) dos surfactantes em Ca(OCl)2 e NaOCl, foram avaliados o pH, cloro livre, tensão superficial e íons de cálcio livre. A penetrabilidade nos túbulos dentinários de NaOCl e Ca(OCl)2, com ou sem cloreto de benzalcônio e Triton X-100 [surfactantes que promoveram a menor tensão superficial de [Ca(OCl)2] foi avaliada utilizando pré-molares humanos corados com cristal violeta. Os testes estatísticos foram ANOVA de uma via e pós-teste de Tukey, Kruskal-Wallis e pós-teste de Dunn, ANOVA de duas vias e pós-teste de Bonferroni, e teste t; dependendo do ensaio. A adição de surfactantes reduziu a tensão superficial do NaOCl e Ca(OCl)2, e não alterou o pH ou cloro livre das soluções. A adição de todos os surfactantes aumentou a disponibilidade de íons de cálcio livre de Ca(OCl)2, principalmente o cloreto de benzalcônio. Ca(OCl)2 apresentou menor penetrabilidade nos túbulos dentinários do que NaOCl, e a adição de surfactantes não aumentou a penetrabilidade de Ca(OCl)2, mas aumentou a penetrabilidade de NaOCl. Pode-se concluir que a adição de surfactantes no Ca(OCl)2 não aumentou a penetrabilidade nos túbulos dentinários, mas promoveu menor tensão superficial, sem alterar os valores de pH ou cloro livre, e maior disponibilidade de íons de cálcio livre em Ca(OCl)2.

Different formulations of peracetic acid: effects on smear layer removal, dentine erosion, cytotoxicity and antibiofilm activity

Abstract Objective: To assess the effects of different peracetic acid (PAA) formulations on smear layer (SL) removal, dentine erosion, cytotoxicity, and antibiofilm activity. Methodology: SL removal and dentine erosion were assessed using 90 premolars, distributed into six groups, according to final irrigation: PAA formulations (1% Sigma, 1% Bacterend OX, 1% Arposept, and 0.09-0.15% Anioxyde), 17% ethylenediaminetetraacetic acid (EDTA), and water (control). Cytotoxicity was assessed by methyl-thiazol-tetrazolium (MTT) and neutral red assays. Antibacterial and antibiofilm effectiveness was evaluated against Enterococcus faecalis. For cytotoxicity and antibiofilm activity assessment, the 2.5% NaOCl was also included. Results: EDTA, Sigma, and Bacterend OX removed more SL than Arposept, Anioxyde, and water (p<0.05). EDTA caused more severe dentine erosion than Sigma and Bacterend OX (p<0.05). Sigma and Bacterend OX had higher cytotoxicity than the other solutions (p<0.05). NaOCl, Bacterend OX, Sigma, and Anioxyde significantly reduced E. faecalis colony-forming units (CFU) (p<0.05). The 2.5% NaOCl solution promoted greater biofilm biomass reduction (p<0.05) than the other solutions. All PAA formulations promoted greater biomass reduction than 17% EDTA (p<0.05). Conclusions: Although Sigma and Bacterend OX had higher cytotoxicity, they had a SL removal capability similar to that of EDTA, were as effective as NaOCl against E. faecalis biofilm, and promoted less dentine erosion than EDTA. Arposept and Anioxyde failed to remove the SL, had lower cytotoxicity, and showed less bacterial activity than NaOCl.

Physicochemical properties and effect of bioceramic root canal filling for primary teeth on osteoblast biology

Abstract Bio-C Pulpecto (Bio-CP) was recently developed as the first bioceramic root filling material for primary teeth. Objective To evaluate the physicochemical properties of radiopacity, setting time, pH, cytocompatibility and potential of Bio-CP to induce mineralisation, compared with (1) Calen thickened with zinc oxide (Calen-ZO), and (2) zinc oxide and eugenol (ZOE). Methodology Physicochemical properties were evaluated according to ISO 6876. Saos-2 (human osteoblast-like cell line) exposed to extracts of the materials were subjected to assays of methyl thiazolyl tetrazolium, neutral red, alkaline phosphatase (ALP) activity and mineralised nodule production. The results were analysed using one-way or two-way ANOVA and Tukey's or Bonferroni's post-tests (α=0.05). Results All the materials showed radiopacity higher than 3 mm Al. Bio-CP had lower pH than Calen-ZO, but higher pH than ZOE. Calen-ZO and Bio-CP did not set. The setting time for ZOE was 110 min. The cytocompatibility order was Calen-ZO > Bio-CP > ZOE (1:2, 1:4 dilutions) and Calen-ZO > Bio-CP = ZOE (1:12, 1:24 dilutions) and Calen-ZO = Bio-CP > ZOE (1:32 dilution). Bio-CP induced greater ALP activity at 7 days, and greater mineralised nodule production, compared to Calen-ZO (p<0.05). Conclusions Bio-CP showed adequate physicochemical properties, cytocompatibility and potential to induce mineralisation.

Radiopacity of endodontic materials using two models for conversion to millimeters of aluminum

Abstract The aims of the present study were to compare conventional radiography, radiographs digitized with a scanner or photographic camera, and digital radiography, used to evaluate the radiopacity of endodontic materials, and to compare the accuracy of linear and quadratic models used to convert radiopacity values to equivalent millimeters of aluminum (mm Al). Specimens of AH Plus, Endofill, Biodentine and BioMTA materials (n = 8) were radiographed next to an aluminum step-wedge using radiographic films and digital radiography systems (FONA CMOS sensor, Kodak CMOS sensor and photosensitive phosphor plate-PSP). Conventional radiographs were digitized using a scanner or photographic digital camera. Digital images of all the radiographic systems were evaluated using dedicated software. Optical density units (ODU) of the specimens and the aluminum step-wedge were evaluated by a photo-densitometer (PTDM), used in conventional radiographs. The radiopacity in equivalent mm Al of the materials was determined by linear and quadratic models, and the coefficients of determination (R2) values were calculated for each model. Radiopacity of the materials ranged from -9% to 25% for digital systems and digitized radiographs, compared to the PTDM (p < 0.05). The R2 values of the quadratic model were higher than those of the linear model. In conclusion, the FONA CMOS sensor showed the lowest radiopacity variability of the methodologies used, compared with the PTDM, except for the BioMTA group (higher than PTDM). The quadratic model showed higher R2 values than the linear model, thus indicating better accuracy and possible adoption to evaluate the radiopacity of endodontic materials.

Effect of peracetic acid used as single irrigant on the smear layer, adhesion, and penetrability of AH Plus

Abstract The aim of this study was to evaluate the effect of peracetic acid (PAA) as a single irrigant on the smear layer, on the intraradicular dentinal bond strength, and on the penetrability of an epoxy-based resin sealer into the dentinal tubules. A total of 120 roots were distributed into 4 groups according to the irrigant used in root canal preparation: 1% PAA (PAA); 2.5% NaOCl followed by final irrigation with 17% EDTA and 2.5% NaOCl (NaOCl-EDTA-NaOCl); 2.5% NaOCl (NaOCl); and saline solution (SS). The smear layer was evaluated using scanning electron microscopy. The bond strength of an epoxy-based resin sealer (AH Plus) to root dentin was evaluated by the push-out test and penetrability of the sealer into dentinal tubules was observed by confocal laser microscopy. The results were analyzed by the Kruskal-Wallis and the Dunn post-test (α = 0.05). The use of 1% PAA as single root canal irrigant provided smear layer removal and improved the penetrability and bond strength of AH Plus to root dentin in a manner similar to that of the NaOCl-EDTA-NaOCl group (p > 0.05). The NaOCl and SS groups had higher values of smear layer and lower values of sealer penetrability and dentin bond strength than the PAA and NaOCl-EDTA-NaOCl groups (p < 0.05). Thus, 1% PAA has the potential to be used as a single irrigant in root canals.

Influence of resin-modified glass ionomer and topical fluoride on levels of Streptococcus mutans in saliva and biofilm adjacent to metallic brackets

Abstract Decalcification of enamel during fixed orthodontic appliance treatment remains a problem. White spot lesions are observed in nearly 50% of patients undergoing orthodontic treatment. The use of fluoride-containing orthodontic materials has shown inconclusive results on their ability to reduce decalcification. The aims of this investigation were to compare the levels of Streptococcus mutans (SM) in saliva and biofilm adjacent to orthodontic brackets retained with a resin-modified glass ionomer cement (RMGIC) (Fuji ORTHO LC) and a light cured composite resin (Transbond XT), and to analyze the influence of topical application of the 1.23% acidulated phosphate fluoride (APF) on SM counts. In a parallel study design, two groups (n=14/15) were used with random allocation and high salivary SM counts before treatment. Biofilm was collected from areas adjacent to the brackets on teeth 13, 22, 33, and 41. Both saliva and biofilm were collected on the 7th, 21st, 35th, and 49th days after appliance placement. Topical fluoride application was carried out on the 35th day. Bonding with RMGIC did not alter SM counts in saliva or biofilm adjacent to the brackets. On the other hand, the biofilm adjacent to brackets retained with composite resin showed a significant increase in SM counts along the trial period. Topical application of 1.23% APF did not reduce salivary or biofilm SM counts regardless of the bonding material. In conclusion, fluoride topical application did not show efficacy in reducing SM. The use of RMGIC as bonding materials allowed a better control of SM cfu counts in dental biofilm hindering the significant increase of these microorganisms along the trial period, which was observed in the biofilm adjacent to the composite material.

Effects of application of texture insoles on the balance of subjects with Multiple Sclerosis / Efeitos da aplicação de palmilhas com textura no equilíbrio de sujeitos com Esclerose Múltipla

Objective: The aim of this study was to evaluate the effects on static and dynamic balance after the use of textured insoles. Method: Fifteen subjects with multiple sclerosis were evaluated before using the insoles, after using them for 1 month, and after 2 months without using, them using the following measuring instruments: the Berg Balance Scale, Dynamic Gait Index, and 10-meter Walk Test, a means of functional gait assessment. Results: Improvement was observed in the Berg Balance Scale and Dynamic Gait Index scores, walking time, number of steps and step length after using the insoles for 1 month. The improvement in Berg Balance Scale score remained after two months without the insoles and there were no changes in gait speed. Conclusion: The use of textured insoles was effective as an intervention to improve static and dynamic balance in patients with multiple sclerosis.(AU)

Objetivo: O objetivo deste estudo foi avaliar os efeitos sobre o equilíbrio estático e dinâmico após o uso de palmilhas texturizadas. Método: Quinze indivíduos com esclerose múltipla foram avaliados antes de usar as palmilhas, após usá-las por 1 mês e depois de 2 meses sem usá-las, utilizando os seguintes instrumentos de medição: a Escala de Equilíbrio de Berg, Dynamic Gait Index e teste de caminhada de 10 metros, meios de avaliação funcional da marcha. Resultados: Houve melhora na pontuação Escala de Equilíbrio de Berg e Dynamic Gait Index, tempo de caminhada, o número de passos e comprimento do passo depois de usar as palmilhas. A melhora permaneceu após dois meses sem as palmilhas e não houve mudanças na velocidade da marcha. Conclusão: O uso de palmilhas texturizadas foi eficaz como uma intervenção para melhorar o equilíbrio estático e dinâmico em pacientes com esclerose múltipla.(AU)

Cytotoxicity and Bioactivity of Calcium Silicate Cements Combined with Niobium Oxide in Different Cell Lines

Abstract The aim of this study was to evaluate the cytotoxicity and bioactivity of calcium silicate-based cements combined with niobium oxide (Nb2O5) micro and nanoparticles, comparing the response in different cell lines. This evaluation used four cell lines: two primary cultures (human dental pulp cells - hDPCs and human dental follicle cells - hDFCs) and two immortalized cultures (human osteoblast-like cells - Saos-2 and mouse periodontal ligament cells - mPDL). The tested materials were: White Portland Cement (PC), mineral trioxide aggregate (MTA), white Portland cement combined with microparticles (PC/Nb2O5µ) or nanoparticles (PC/Nb2O5n) of niobium oxide (Nb2O5). Cytotoxicity was evaluated by the methylthiazolyldiphenyl-tetrazolium bromide (MTT) and trypan blue exclusion assays and bioactivity by alkaline phosphatase (ALP) enzyme activity. Results were analyzed by ANOVA and Tukey test (a=0.05). PC/Nb2O5n presented similar or higher cell viability than PC/Nb2O5µ in all cell lines. Moreover, the materials presented similar or higher cell viability than MTA. Saos-2 exhibited high ALP activity, highlighting PC/Nb2O5µ material at 7 days of exposure. In conclusion, calcium silicate cements combined with micro and nanoparticles of Nb2O5 presented cytocompatibility and bioactivity, demonstrating the potential of Nb2O5 as an alternative radiopacifier agent for these cements. The different cell lines had similar response to cytotoxicity evaluation of calcium silicate cements. However, bioactivity was more accurately detected in human osteoblast-like cell line, Saos-2.

Resumo O objetivo deste estudo foi avaliar a citotoxicidade e bioatividade de cimentos à base de silicato de cálcio associados com óxido de nióbio (Nb2O5) micro e nanoparticulados, e comparar a resposta em diferentes linhagens celulares. Foram utilizadas quatro linhagens celulares: duas culturas primárias (células da polpa dentária humana - hDPCs e células do folículo dentário humano - hDFCs) e duas culturas imortalizadas (células osteoblásticas humanas - Saos-2 e células do ligamento periodontal de ratos - mPDL). Os materiais analisados foram: Cimento Portland branco (PC); Agregado trióxido mineral (MTA); PC associado com micropartículas (PC/Nb2O5µ) ou nanopartículas (PC/Nb2O5n) de óxido de nióbio (Nb2O5). A citotoxicidade foi avaliada pelos ensaios de brometo de metil-tiazolil-difeniltetrazólio (MTT) e azul de tripan, e a bioatividade pela atividade da enzima fosfatase alcalina (ALP). Os resultados foram analisados por ANOVA e teste de Tukey (a=0,05). O grupo do PC/Nb2O5n apresentou viabilidade celular semelhante ou maior do que o grupo do PC/Nb2O5μ em todas as linhagens celulares. Além disso, ambos os grupos apresentaram viabilidade celular semelhante ou maior do que o MTA. Saos-2 apresentaram maior atividade de ALP, com destaque para o material PC/Nb2O5μ aos 7 dias de exposição. Concluiu-se que cimentos de silicato de cálcio associados com Nb2O5 micro ou nanoparticulado apresentaram citocompatibilidade e bioatividade, demonstrando potencial do Nb2O5 como agente radiopacificador alternativo para estes cimentos. As linhagens celulares estudadas apresentaram resposta semelhante na avaliação da citotoxicidade de cimentos de silicato de cálcio. No entanto, a bioatividade é melhor detectada na linhagem de células osteoblásticas humanas, Saos-2.

Effect of addition of nano-hydroxyapatite on physico-chemical and antibiofilm properties of calcium silicate cements

ABSTRACT Objective Mineral Trioxide Aggregate (MTA) is a calcium silicate cement composed of Portland cement (PC) and bismuth oxide. Hydroxyapatite has been incorporated to enhance mechanical and biological properties of dental materials. This study evaluated physicochemical and mechanical properties and antibiofilm activity of MTA and PC associated with zirconium oxide (ZrO2) and hydroxyapatite nanoparticles (HAn). Material and Methods White MTA (Angelus, Brazil); PC (70%)+ZrO2 (30%); PC (60%)+ZrO2 (30%)+HAn (10%); PC (50%)+ZrO2 (30%)+HAn (20%) were evaluated. The pH was assessed by a digital pH-meter and solubility by mass loss. Setting time was evaluated by using Gilmore needles. Compressive strength was analyzed by mechanical test. Samples were radiographed alongside an aluminum step wedge to evaluate radiopacity. For the antibiofilm evaluation, materials were placed in direct contact with E. faecalis biofilm induced on dentine blocks. The number of colony-forming units (CFU mL-1) in the remaining biolfilm was evaluated. The results were submitted to ANOVA and the Tukey test, with 5% significance. Results There was no difference in pH levels of PC+ZrO2, PC+ZrO2+HAn (10%) and PC+ZrO2+HAn (20%) (p>0.05) and these cements presented higher pH levels than MTA (p<0.05). The highest solubility was observed in PC+ZrO2+HAn (10%) and PC+ZrO2+HAn (20%) (p<0.05). MTA had the shortest initial setting time (p<0.05). All the materials showed radiopacity higher than 3 mmAl. PC+ZrO2 and MTA had the highest compressive strength (p<0.05). Materials did not completely neutralize the bacterial biofilm, but the association with HAn provided greater bacterial reduction than MTA and PC+ZrO2 (p<0.05) after the post-manipulation period of 2 days. Conclusions The addition of HAn to PC associated with ZrO2 harmed the compressive strength and solubility. On the other hand, HAn did not change the pH and the initial setting time, but improved the radiopacity (HAn 10%), the final setting time and the E. faecalis antibiofilm activity of the cement.

Comparação da deformação e degradação de força entre elásticos látex e não látex – estudo in vitro / Comparison of deformation and force decay between latex and non latex elastics – in vitro study

A Ortodontia, desde que surgiu como especialidade, faz uso de elásticos para correção das más oclusões, sendo impossível imaginar um tratamento ortodôntico corretivo sem essa ferramenta. O objetivo deste estudo foi testar a hipótese que elásticos 1/8”, 3/16”, 1/4” e 5/16” não látex sofrem maior deformação e degradação que elásticos látex de mesmo diâmetro. O modelo experimental foi constituído de placa de acrílico contendo bráquetes ortodônticos e os elásticos foram inseridos no bráquete do canino e segundo pré-molar. O diâmetro interno e a magnitude de força de cada elástico foram mensurados nos intervalos de 0, 24 horas, 72 horas e 504 horas. A amostra foi armazenada em saliva artificial em temperatura ambiente durante todo período de avaliação e os elásticos foram removidos e novamente inseridos três vezes ao dia para simular as trocas realizadas pelo paciente. O diâmetro interno e a magnitude de força entre os elásticos látex e não látex nos diferentes períodos experimentais foram comparados pela ANOVA de medidas repetidas e pelo pós-teste de Bonferroni. A deformação dos elásticos de látex foi menor e mais uniforme do que os de não látex. Elásticos não látex apresentaram maior degradação de força do que os de látex em todos os períodos.

Since Orthodontics emerged as specialty elastics are used for malocclusion correction. It is impossible to imagine a corrective treatment without this tool. The objective of this study was to test the hypothesis that 1/8”, 3/16”, 1/4” and 5/16 non-latex intermaxillary elastics suffer bigger deformation and degradation over time than latex elastics of the same diameter. The experimental model consisted of an acrylic plate containing orthodontic brackets and the elastics were inserted in brackets of the canine and second bicuspid. Internal diameter and magnitude of force of each elastic were measured at intervals from 24 hours, 72 hours, and 504 hours. The sample was stored in artificial saliva at room temperature throughout the evaluation period and the elastics were removed and reinstalled at the plates three times daily in order to simulate the changes made by the patient. The internal diameter and magnitude of force between the non-latex and latex elastics at the different periods were compared by ANOVA with repeated measures and the Bonferroni post-test. The deformation of the latex elastics was lower and more uniform than those of non-latex. The non-latex elastics showed higher force degradation than latex in all periods.

Fracture resistance of endodontically-treated teeth submitted to bleaching treatment with hydrogen peroxide and titanium dioxide nanoparticles photoactivated by LED-laser / Resistência à fratura de dentes tratados endodonticamente submetidos a tratamento clareador com peróxido de hidrogênio e nanopartículas de dióxido de titânio fotoativado por LED-laser

Objective: The aim of this study was evaluate the fracture resistance of endodontically-treated teeth after bleaching treatment using 15% hydrogen peroxide plus titanium dioxide nanoparticles (15HPTiO2) photoactivated by LED-laser, in comparison with protocols using 35% hydrogen peroxide (35HP), 37% carbamide peroxide (37CP) or sodium perborate (SP). Material and method: After endodontic treatment, fifty bovine extracted incisors were divided into five groups (n = 10): G1- without bleaching; G2- 35HP; G3- 37CP; G4- 15HPTiO2 photoactivated by LED-laser and G5- SP. In G2 and G4, the bleaching protocol was applied in 4 sessions, with a 7 day interval between each session. In G3 and G5, the materials were kept in the pulp chamber for 21 days, but replaced every 7 days. After 21 days, the crowns were subjected to compressive load at a cross head speed of 0.5 mm/min, applied at 135° to the long axis of the root using an eletromechanical testing machine, until fracture. The data were submitted to ANOVA and Tukey tests (p = 0.05). Result: The bleaching treatment in endodontically-treated teeth with 15HP plus TiO2 nanoparticles and photoactivated by LED-laser caused reduction of the fracture resistance similarly provided by 35HP, 37CP or SP (p>0.05). All bleaching treatments reduced the fracture resistance compared to unbleached teeth (p<0.05). Conclusion: All bleaching protocols reduced the fracture resistance of endodontically-treated teeth, but there were no differences between each other. .

Objetivo: Avaliar a resistência à fratura de dentes tratados endodonticamente após tratamento clareador usando peroxido de hidrogênio a 15% com nanopartículas de dióxido de titânio (15HPTiO2) fotoativado por LED-laser, em comparação aos protocolos usando peróxido de hidrogênio 35% (35HP), peróxido de carbamida 37% (37CP) ou perborato de sódio (SP). Material e método: Após tratamento endodôntico, 50 incisivos bovinos extraídos foram divididos em 5 grupos (n = 10): G1- sem clareamento; G2- 35HP; G3- 37CP; G4- 15HPTiO2 fotoativado por LED-laser e G5- SP. Nos grupos G2 e G4, o protocolo de clareamento foi aplicado em 4 sessões, com 7 dias de intervalo entre cada sessão. Nos grupos G3 e G5, os materiais foram inseridos na câmara pulpar por 21 dias e trocados a cada 7 dias. Após 21 dias, as coroas foram submetidas à força de compressão com velocidade de 0,5 mm/min, aplicada a 135º em relação ao longo eixo da raiz. empregando máquina de ensaios mecânicos, até a fratura. Os dados foram submetidos aos testes de ANOVA e Tukey (p = 0.05). Resultado: O tratamento clareador em dentes tratados endodonticamente com 15HP e nanopartículas de TiO2 fotoativado por LED-laser proporcionou redução da resistência à fratura semelhante ao 35HP, 37CP ou SP (p>0,05). Todos os tratamentos clareadores reduziram a resistência coronária à fratura quando comparados aos dentes sem tratamento (p<0,05). Conclusão: Todos os protocolos de clareamento reduziram a resistência à fratura dos dentes tratados endodonticamente, sem diferenças estatisticamente significantes entre os grupos. .

Effects of calcium hydroxide addition on the physical and chemical properties of a calcium silicate-based sealer

Recently, various calcium silicate-based sealers have been introduced for use in root canal filling. The MTA Fillapex is one of these sealers, but some of its physicochemical properties are not in accordance with the ISO requirements. Objective: The aim of this study was to evaluate the flowability, pH level and calcium release of pure MTA Fillapex (MTAF) or containing 5% (MTAF5) or 10% (MTAF10) calcium hydroxide (CH), in weight, in comparison with AH Plus sealer. Material and Methods: The flowability test was performed according to the ISO 6876:2001 requirements. For the pH level and calcium ion release analyses, the sealers were placed individually (n=10) in plastic tubes and immersed in deionized water. After 24 hours, 7 and 14 days, the water in which each specimen had been immersed was evaluated to determine the pH level changes and calcium released. Flowability, pH level and calcium release data were analyzed statistically by the ANOVA test (α=5%). Results: In relation to flowability: MTAF>AH Plus>MTAF5>MTAF10. In relation to the pH level, for 24 h: MTAF5=MTAF10=MTAF>AH Plus; for 7 and 14 days: MTAF5=MTAF10>MTAF>AH Plus. For the calcium release, for all periods: MTAF>MTAF5=MTAF10>AH Plus. Conclusions: The addition of 5% CH to the MTA Fillapex (in weight) is an alternative to reduce the high flowability presented by the sealer, without interfering in its alkalization potential. .

Influence of Sealer Placement Technique on the Quality of Root Canal Filling by Lateral Compaction or Single Cone

The aim of this study was to evaluate the influence of the sealer placement technique on the quality of root canal filling using Lateral Compaction (LC) or Single Cone (SC). In order to do that, 60 mesial roots of mandibular first molars were prepared and divided into 2 groups (n=30), according to the filling technique: LC and SC. Each group was subdivided into 3 subgroups (n=10), according to the different sealer placement methods: A: Master gutta-percha (GP) cone; B: Lentulo spiral; C: File. The roots were sectioned at 2, 4 and 6 mm from the apex and photographed with the aid of a digital microscope. Then, areas of GP, endodontic sealer and voids were measured, and these data were subjected to statistical analysis. LC technique showed no statistically difference (p>0.05) in the percentage of GP area, sealer and voids between the subgroups at any of the three levels. After use of SC, higher percentages of sealer area were found at all levels (p<0.01) when the sealer was placed with a file. At 2 mm, higher percentage of void areas (p<0.05) was observed when the cone was used, lower percentage with K-file and the lowest percentage with Lentulo. At 4 mm, cone showed higher percentage of void areas (p<0.05). At 6 mm, there were no significant differences (p>0.05) between the three methods. Considering these results, using an instrument for sealer placement was important in the SC technique to reduce voids. Regarding LC, the sealer placement techniques provided similar results.

O objetivo deste estudo foi avaliar a influência das técnicas de inserção de cimento endodôntico na qualidade da obturação, usando Compactação Lateral Ativa (CLA) e Cone Único. Para tal, 60 raízes mesiais de primeiros molares inferiores foram preparadas e divididas em 2 grupos (n=30), de acordo com a técnica de obturação: CLA e Cone único. Cada grupo foi subdividido em 3 subgrupos (n=10), de acordo com as diferentes técnicas de inserção aplicadas: A - Cone de guta-percha principal; B - Lentulo; C - Lima. As raízes foram seccionadas a 2, 4 e 6 mm do ápice e fotografadas com microscópio digital. Então, as áreas de guta-percha, cimento endodôntico e falhas foram medidas e tais dados foram submetidos à análise estatística. CLA não revelou diferenças estatisticamente significantes (p>0,05) nas porcentagens das áreas de guta-percha, de cimento endodôntico e de falhas, em nenhum dos grupos ou níveis de corte. Com a aplicação da técnica do Cone Único, maiores porcentagens de área de cimento foram encontradas nos três níveis (p<0,01) quando este foi inserido por meio de uma lima. Aos 2 mm, a maior porcentagem de área de falhas (p<0,05) foi observada quando o cone foi utilizado. Uma porcentagem menor foi encontrada quando foi utilizada a lima; e a menor porcentagem foi observada com o Lentulo. Aos 4 mm, a inserção por meio do cone apresentou maior porcentagem de falhas (p<0,05). Aos 6 mm, não houve diferença estatisticamente significante (p>0,05) entre os três métodos. Considerando esses resultados, foi importante o uso de um instrumento para a inserção do cimento quando a técnica do Cone Único foi aplicada. Já com CLA, qualquer técnica de inserção de cimento apresentou resultados similares.

The impact of the addition of iodoform on the physicochemical properties of an epoxy-based endodontic sealer

Due to the low radiopacity of Sealer 26, iodoform is frequently empirically added to this sealer. Thus, the interference of this procedure with the physicochemical properties of Sealer 26 must be evaluated. Objective: This study evaluated the influence of the addition of iodoform on setting time, flow, solubility, pH, and calcium release of an epoxy-based sealer. Material and Methods: The control group was pure Sealer 26, and the experimental groups were Sealer 26 added with 1.1 g, 0.55 g or 0.275 g of iodoform. Setting time evaluation was performed in accordance with the ASTM C266-03 speciflcation. The analysis of flow and solubility was in accordance with the ISO 6876-2001 speciflcation. For the evaluation of pH and calcium ion release, polyethylene tubes were filled with the materials and immersed in flasks with 10 ml of deionized water. After 24 h, 7, 14, 21, 28, and 45 days pH was measured. In 45 days, the calcium released was evaluated with an atomic absorption spectrophotometer. Results: The addition of iodoform increased setting time in comparison with pure sealer (P<0.05). As for flow, solubility, and calcium release, the mixtures presented results similar to pure sealer (p>0.05). In the 24 h period, the mixture with 1.1 g and 0.55 g of iodoform showed lower pH than pure sealer and than sealer added with 0.275 g of iodoform (P<0.05). Conclusions: The iodoform added to Sealer 26 interferes with its setting time and solubility properties. Further studies are needed to address the clinical signiflcance of this interference. .

Evaluation of the pH, calcium release and antibacterial activity of MTA Fillapex / Avaliação do pH, liberação de cálcio e atividade antibacteriana do MTA Fillapex

Objetivo: O estudo avaliou, em diversos períodos de análise, o pH e liberação de cálcio e a atividade antibacteriana proporcionada pelo MTA Fillapex, em relação ao Sealapex e AH Plus. Material e Método: Tubos de polietilenos foram preenchidos com um dos cimentos e imersos em água destilada. Após de 24 horas, 14 e 28 dias, o valor do pH e o cálcio liberado pelos cimentos foram avaliados diretamente na água destilada em que os espécimes permaneceram imersos. A atividade antibacteriana dos cimentos foi avaliada em culturas de Enterococcus faecalis ou Staphylococcus aureus, por meio do teste de difusão em ágar. Os dados obtidos foram submetidos aos testes de ANOVA e Tukey (α=0.05). Resultado: Em todos os períodos analizados, o Sealapex proporcionou os maiores valores de pH (p<0,05) em relação aos demais cimentos e o MTA Fillapex proporcionou maiores valores que o dos AH Plus (p<0,05). Em 14 dias, o MTA Fillapex promoveu maior liberação de cálcio que o proporcionado pelo Sealapex (p<0,05). Em 28 dias, o Sealapex proporcionou maior liberação de cálcio que o MTA Fillapex (p<0,05). Em todos os períodos, o AH Plus apresentou a menor liberação de cálcio em relação aos outros cimentos (p<0,05). Em relação ao E. faecalis, não foram observadas diferenças (p>0,05) entre as zonas de inibição de crescimento bacteriano produzidas pelos diveros cimentos. Em relação ao S. aureus, o Sealapex apresentou maior atividade antibacteriana que o MTA Fillapex e o AH Plus (p<0,05), que por sua vez foram semelhantes entre si (p>0,05). Conclusão: Após o período final de avaliação, o pH e a liberação de cálcio proporcionado pelo MTA Fillapex foram menores que os do Sealapex e maiores que os do AH Plus. A atividade antimicrobiana do MTA Fillapex não diferiu dos demais cimentos endodônticos.

Objective: This study evaluated, in several analysis periods, pH and calcium release and antibacterial activity provided by MTA Fillapex sealer compared to Sealapex and AH Plus sealers. Material and Method: Polyethylene tubes were filled with a sealer and immersed in distilled water. After 24 hours, 14 and 28 days, pH and calcium release by endodontic sealers were evaluated directly in water which the tubes were stored. Sealers antibacterial activity was evaluated against Enterococcus faecalis and Staphylococcus aureus by means of agar diffusion test. All data were submitted to ANOVA and Tukey tests (α=0.05). Result: In all periods evaluated, Sealapex had the highest pH value (p<0.05) in comparison to other sealers and MTA Fillapex provided higher pH values than AH Plus (p<0.05). In 14-days period, MTA Fillapex had greater calcium release value than Sealapex (p<0.05). In 28-days period, Sealapex provided higher calcium release than MTA Fillapex (p<0.05). In all periods, AH Plus provided lower calcium release than other sealers (p<0.05). In relation to E. faecalis, there were no differences among the sealers, in relation to antibacterial activity (p>0.05). In relation to S. aureus, Sealapex presented better antibacterial effectiveness than the MTA Fillapex and AH Plus (p<0.05), which were similar each other (p>0.05). Conclusion: In final evaluation period, pH values and calcium release provided by MTA Fillapex were lower than provided by Sealapex and higher than provided by AH Plus. The MTA Fillapex antimicrobial action was similar to other endodontic sealers.

The efficacy of the self-adjusting file and ProTaper for removal of calcium hydroxide from root canals

OBJECTIVE: The goal of this study was to evaluate the efficacy of the Self-Adjusting File (SAF) and ProTaper for removing calcium hydroxide [Ca(OH)2] from root canals. MATERIAL AND METHODS: Thirty-six human mandibular incisors were instrumented with the ProTaper system up to instrument F2 and filled with a Ca(OH)2-based dressing. After 7 days, specimens were distributed in two groups (n=15) according to the method of Ca(OH)2 removal. Group I (SAF) was irrigated with 5 mL of NaOCl and SAF was used for 30 seconds under constant irrigation with 5 mL of NaOCl using the Vatea irrigation device, followed by irrigation with 3 mL of EDTA and 5 mL of NaOCl. Group II (ProTaper) was irrigated with 5 mL of NaOCl, the F2 instrument was used for 30 seconds, followed by irrigation with 5 mL of NaOCl, 3 mL of EDTA, and 5 mL of NaOCl. In 3 teeth Ca(OH)2 was not removed (positive control) and in 3 teeth canals were not filled with Ca(OH)2 (negative control). Teeth were sectioned and prepared for the scanning electron microscopy. The amounts of residual Ca(OH)2 were evaluated in the middle and apical thirds using a 5-score system. RESULTS: None of the techniques completely removed the Ca(OH)2 dressing. No difference was observed between SAF and ProTaper in removing Ca(OH)2 in the middle (P=0.11) and the apical (P=0.23) thirds. CONCLUSION: The SAF system showed similar efficacy to rotary instrument for removal of Ca(OH)2 from mandibular incisor root canals. .

Incomplete vertical root fracture associated with lateral compactiontechnique: a microscopic analysis / Fratura radicular vertical incompleta associada com a técnica de condensação lateral: Análise microscópica

Objective: This study evaluated the effects of root canal obturation employing lateral compaction technique and spreader load of 1.5 kg on the incidence of complete (CVRF) or incomplete vertical root fractures (IVRF). Material and Methods: Twenty-seven distal roots of extracted human mandibular molars were used. All root canals were prepared by biomechanical step-back technique and obturated by lateral compaction technique. The prepared roots were distributed into two groups: G1- experimental (n = 17)= and G2- control (n = 10). During obturation, load of 1.5 kg was applied to a size # 30 finger spreader. Pre- and post-obturation images of the coronal portion of the roots were captured by inverted digital microscopy and analyzed by one trained examiner. Data were evaluated by Fisher’s test (p < 0.05) using GrapH Pad Prism 5.0. Results: No roots exhibited CVRF. All fractures observed before and after obturation were IVRF or “other defects”. In G2 (control group), there was no increase of IVRF number. Interestingly, G1 presented an increase in the IVRF number to 70.59% in the 12 teeth out of 17 teeth studied. The statistical analysis showed that the mean of IVRF increased significantly in G1 when compared to G2 (p < 0.05). Conclusion: The application of a 1.5 kg spreader load during lateral compaction technique does not produce complete vertical root fractures, but may produce incomplete fractures or “other defects”.

Objetivo: Este estudo avaliou os efeitos da obturação dos canais radiculares, empregando a técnica de condensação lateral com uma força do espaçador de 1,5 kg, na incidência de fraturas radiculares verticais completas (FRVC) ou incompletas (FRVI). Material e Métodos: Foram usadas 27 raízes distais de dentes molares mandibulares humanosextraídos. Todas as raízes foram instrumentadas por meio da técnica clássica ápice-coroa e obturadas pela técnica de condensação lateral. Após o preparo biomecânico, as raízes foram distribuídas em 2 grupos: G1- experimental (n = 17) e G2- controle (n = 10). Durante a obturação, uma força de 1,5 kg foi aplicada ao espaçador digital # 30. As imagens pré- e pós-obturação da superfície coronal das raízes foram capturadas por meio de um microscópio digital invertido e analisadas por um examinador treinado. Os dados obtidos foram avaliados por meio do teste de Fisher (p < 0,05) usando o programa GrapH Pad Prism 5.0. Resultados: Não foram detectadas FRVC. Todas as fraturas observadas antes e após a obturação foram FRVI ou “outros defeitos”. No G2 (grupo controle), não houve um aumento no número de FRVI. Curiosamente, G1 apresentou um aumento das FRVI em 70,59% (12/17 raízes). A análise estatística mostrou que a média de FRVI aumentou significativamente no G1 quando comparado ao G2 (p < 0,05). Conclusão: A aplicação de uma força de 1,5 kg ao espaçador durante a realização da técnica de condensação lateral não produz fraturas radiculares verticais completas, mas pode produzir fraturas incompletas ou “outros defeitos”.

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.

Interference of the assessment method in pH values of an epoxy-based cement

Introduction :Alkalinization potential is a fundamental property of endodontic epoxy-based cements containing calcium hydroxide. Studies have shown discrepant pH results for same materials at different evaluation periods. A possible reason accounting for these differences may be the assessment procedures. Objective: To evaluate the pH value of an epoxy-based cement (Sealer 26) in different periods of analysis, using two assessment methods. Material and methods:Sealer 26 was manipulated and immediately placed into polyethylene tubes (n=10, each group) and immersed in distilled water. In G1, the tubes were kept in the same water during all experiment; and in G2, the tubes were removed and placed into another flask with an equal amount of water after the pH evaluation. The pH of these solutions was measured at 24 hours, 7, 14 and 28 days. Analysis were made within the same group according to the experimental periods and between groups in each experimental period. Data were submitted to ANOVA (a = 5%) and t test, respectively.Results:For G1 and G2, all periods showed different pH values (p < 0.05), except between 14 and 28 days (p > 0.05) and between 7 and 14 days (p > 0.05), respectively. In each period, no significant differences were observed between the groups.Conclusion: The method to obtain the pH values in different experimental periods no interfered in the final results. However, difference was observed when the results were analyzed at same group.

Clinical evaluation of the failure rate of metallic brackets bonded with orthodontic composites

The purpose of the present study was to evaluate in vivo the failure rate of metallic brackets bonded with two orthodontic composites. Nineteen patients with ages ranging from 10.5 to 38.7 years needing corrective orthodontic treatment were selected for study. The enamel surfaces from second premolars to second premolars were treated with Transbond Plus-Self Etching Primer (3M Unitek). Next, 380 orthodontic brackets were bonded on maxillary and mandibular teeth, as follows: 190 with Transbond XT composite (3M Unitek) (control) and 190 with Transbond Plus Color Change (3M Unitek) (experimental) in contralateral quadrants. The bonded brackets were light cured for 40 s, and initial alignment archwires were inserted. Bond failure rates were recorded over a six-month period. At the end of the evaluation, six bond failures occurred, three for each composite. Kaplan-Meyer method and log-rank test (Mantel-Cox) was used for statistical analysis, and no statistically significant difference was found between the materials (p=0.999). Both Transbond XT and Transbond Plus Color Change composites had low debonding rates over the study period.

O objetivo do presente estudo foi avaliar in vivo a taxa de falha de braquetes metálicos colados com dois compósitos ortodônticos. Dezenove pacientes com idades entre 10,5 e 38,7 anos, que necessitavam de tratamento ortodôntico corretivo, foram selecionados para estudo. As superfícies de esmalte de segundos pré-molares a segundos pré-molares foram tratadas com Transbond Plus Self-Etching Primer (3M Unitek). Em seguida, 380 bráquetes foram colados nos dentes superiores e inferiores, como segue: 190 com compósito Transbond XT (3M Unitek) (controle) e 190 com Transbond Plus Color Change (3M Unitek) (experimental), em quadrantes contralaterais. Os bráquetes colados foram fotopolimerizados por 40 s e arcos de alinhamento inicial foram inseridos. As taxas de insucesso na adesão foram registrados durante um período de seis meses. No final da avaliação, seis falhas de adesão ocorreram, três para cada composto. Para a análise estatística foram utilizados os testes de Kaplan-Meyer e log-rank (Mantel-Cox), e não houve diferença estatisticamente significante entre os materiais (p=0,999). Ambos compósitos, Transbond XT e Transbond Plus Color Change, tiveram baixas taxas de descolagem durante o período de estudo.