Effects of Alternative Solvents in Experimental Enamel Infiltrants on Bond Strength and Selected Properties.

Objective: To evaluate different concentrations of solvents (tetrahydrofuran (THF) and dimethyl sulfoxide (DMSO) and monomers on the degree of conversion, microtensile bond strength, and mechanical properties of experimental resin infiltrants. Materials and Methods: Resin infiltrants were formulated and divided into eleven groups: (1) Icon, (2) 75% TEGDMA (T) +25% UDMA (U), (3) T +25% BIS-EMA (B), (4) T + U +0.5%DMSO, (5) T + U +5% DMSO, (6) T + U +0.5% THF, (7) T + U +5% THF, (8) T + B +0.5% DMSO, (9) T + B +5% DMSO, (10) T + B +0.5% THF, and (11) T + B +5% THF. One hundred and ten bovine mandibular incisors were sectioned, treated, and destined to the degree of conversion, tensile cohesive strength, microtensile bond strength, flexural strength, and elastic modulus. Data were submitted to one-way ANOVA and Tukey's test (α = 0.05). Results: The degree of conversion was lowest for T + B +5%THF (41.9%) and highest for T + U +5%THF (62.1%). In flexural strength and E-modulus, the T + B (96.5 MPa and 0.49 GPa) obtained the highest values and the lowest for T + U +5% DMSO (18.5 MPa and 9.7 GPa). Icon showed the highest bond strength (19.3 MPa) and cohesive strength (62.2 MPa), while T + U +5%DMSO (9.7 MPa) and T + B +5% DMSO (9.8 MPa) the lowest values and T + B +0.5% DMSO (12.3 MPa) the lowest cohesive strength. Conclusions: The addition of lower concentrations of DMSO or THF (0.5%) did not impair bond strength or significantly affect monomer conversion, but reduced the mechanical properties of resin infiltration.

Influência da ativação ultrassônica e veículo no pH dentinário em dentes com reabsorção radicular externa simulada reparados com MTA / Influence of ultrasonic activation and mixing vehicle on dentinal pH in simulated external root resorptions repaired with MTA

Avaliar o efeito da ativação ultrassônica e do veículo do MTA no pH dentinário em dentes com reabsorção radicular externa simulada. Métodos: Uma cavidade foi preparada na superfície radicular de 46 dentes bovinos, as quais foram seladas com MTA preparado com 100% de água destilada (DW) ou com 80% DW e 20% de propilenoglicol (PG). Os dentes foram divididos em quatro grupos (n = 10), de acordo com o veículo e o protocolo de ativação ultrassônica utilizado durante a inserção do material (ativação ou sem ativação). O grupo controle (n = 6) foi deixado sem selamento. O pH foi mensurado após 15, 30 e 60 dias de imersão. Resultados: A ativação com ultrassom não alterou significativamente o pH (p>0,05). Os cimentos manipulados utilizando DW + PG apresentaram maior pH aos 15 dias, em relação ao MTA manipulado com DW (p<0,05). Conclusão: A associação de 80% de água destilada com 20% de propilenoglicol aumentou o pH dentinário, o que é positivo para o reparo de reabsorções radiculares (AU).

The aim of this study was to evaluate the effect of ultrasonic activation and MTA vehicle on dentinal pH in simulated external root resorptions. So, a cavity was prepared in the root of forty-six bovine teeth. They were filled with MTA mixed with 100% distilled water (DW) or MTA mixed with 80% DW and 20% propylene glycol (PG). Teeth were divided into four groups (n = 10), according to the vehicle (DW or PG) and ultrasonic protocol used for material insertion (activated or not). Control group (n = 6) was unfilled. The pH was assessed after 15, 30 and 60 days of immersion. As results of all that, activation with ultrasound did not significantly alter the pH (p > 0.05). The cements were mixed with either DW or DW + PG, with the later association presenting higher pH at 15 days of assessment than the former (p < 0.05). Thereby, it can be concluded that mixing MTA with 80% DW and 20% PG increased the dentinal pH, which is positive for root resorption repair (AU).

Effect of a resin-modified glass-ionomer with calcium on enamel demineralization inhibition: an in vitro study.

We assessed the effect of a new coating material based on resin-modified glass-ionomer with calcium (Ca) in inhibiting the demineralization of underlying and adjacent areas surrounding caries-like lesions in enamel. The measures used were surface hardness (SH) and cross-sectional hardness (CSH). Thirty-six bovine enamel specimens (3 × 6 × 2 mm) were randomly allocated into three groups (n = 12): No treatment (NT); resin-modified glass-ionomer with Ca (Clinpro XT Varnish, 3M ESPE) (CL), and fluoride varnish (Duraphat, Colgate) (DU). The specimens were subjected to alternated immersions in demineralizing (6 h) and remineralizing solutions (18 h) for 7 days. SH measurements were conducted at standard distances of 150, 300, and 450 µm from the treatment area. CSH evaluated the mean hardness profile over the depth of the enamel surface and at standard distances from the materials. The energy-dispersive X-ray spectroscopy analysis was conducted to evaluate the demineralization bands created on the sublayer by % of calcium (Ca), phosphorus (P), and fluoride (F). Ca/P weight ratio was also calculated. Based on SH and CSH measurements, there was no difference between groups at the distances 150 µm (p = 0.882), 300 µm (p = 0.995), and 450 µm (p = 0.998). Up to 50 µm depth (at 150 µm from the treatment area), CL showed better performance than DU ( p< 0.05). NT presented higher loss of Ca and P than CL and DU (p < 0.05). There was no significant difference in the % of F ion among the three groups. The new coating material was similar to F varnish in attenuating enamel demineralization.

Effect of a resin-modified glass-ionomer with calcium on enamel demineralization inhibition: an in vitro study

Abstract We assessed the effect of a new coating material based on resin-modified glass-ionomer with calcium (Ca) in inhibiting the demineralization of underlying and adjacent areas surrounding caries-like lesions in enamel. The measures used were surface hardness (SH) and cross-sectional hardness (CSH). Thirty-six bovine enamel specimens (3 × 6 × 2 mm) were randomly allocated into three groups (n = 12): No treatment (NT); resin-modified glass-ionomer with Ca (Clinpro XT Varnish, 3M ESPE) (CL), and fluoride varnish (Duraphat, Colgate) (DU). The specimens were subjected to alternated immersions in demineralizing (6 h) and remineralizing solutions (18 h) for 7 days. SH measurements were conducted at standard distances of 150, 300, and 450 µm from the treatment area. CSH evaluated the mean hardness profile over the depth of the enamel surface and at standard distances from the materials. The energy-dispersive X-ray spectroscopy analysis was conducted to evaluate the demineralization bands created on the sublayer by % of calcium (Ca), phosphorus (P), and fluoride (F). Ca/P weight ratio was also calculated. Based on SH and CSH measurements, there was no difference between groups at the distances 150 µm (p = 0.882), 300 µm (p = 0.995), and 450 µm (p = 0.998). Up to 50 µm depth (at 150 µm from the treatment area), CL showed better performance than DU ( p< 0.05). NT presented higher loss of Ca and P than CL and DU (p < 0.05). There was no significant difference in the % of F ion among the three groups. The new coating material was similar to F varnish in attenuating enamel demineralization.

Laser therapy as an adjunct in the treatment of sodium hypochlorite extrusion through a root perforation: a case report.

Accidental sodium hypochlorite extrusion can occur during endodontic irrigation procedures. The symptoms appear immediately and include severe pain, swelling, and probable tissue necrosis adjacent to the root of the treated tooth. Treatment of sodium hypochlorite extrusion involves immediate and copious saline irrigation to neutralize the area and prescription of analgesic, anti-inflammatory, and antibiotic medications. Low-level laser therapy (LLLT) might be useful as an adjuvant treatment for damaged soft tissues to improve healing. This case report describes the treatment of accidental extrusion of 1% sodium hypochlorite through a root canal perforation in a mandibular incisor during endodontic treatment. The extrusion caused minor swelling within the mentolabial sulcus and a large area of necrosis in the gingivolabial mucosa and right edentulous premolar area. Conventional treatment was performed in association with LLLT. Clinical and radiographic examinations after 6 months showed complete healing of the necrotic area without paresthesia and the repair of apical tissues.

Análise do EDTA tetrassódico associado ao hipoclorito de sódio no preparo biomecânico dos canais radiculares e em protocolos de irrigação final / Analysis of tetrasodium EDTA associated with sodium hypochlorite in the preparation biomechanical parameters of root canals and in final irrigation protocols

Introdução: O objetivo deste estudo foi avaliar a associação do hipoclorito de sódio e EDTANa4 como irrigante comparado ao EDTANa3 quanto a capacidade de limpeza, preparo biomecânico e na irrigação final, associados ou não com a agitação ultrassônica. Materiais e Método: Foram utilizados 40 pré-molares inferiores, instrumentados e analisados em MEV para comprovar a formação de smear-layer. Realizou-se então os protocolos de irrigação utilizando diferentes associações, associadas ou não a agitação ultrassônica. Resultados: O EDTA trissódico agitado ou não com ultrassom, favoreceu limpeza significante (P<0.05) apenas nos terços médio e cervical, enquanto que para o EDTA tetrassódico sem agitação a limpeza foi significante (P<0.05) apenas no terço médio. Comparando os irrigantes, independente do método de irrigação, houve diferença estatisticamente significante (P<0.05) apenas no terço médio na comparação entre o EDTA trissódico pela irrigação convencional e EDTA tetrassódico pela irrigação convencional. Conclusão: O EDTA trissódico favoreceu uma melhor limpeza em relação ao EDTA tetrassódico, principalmente no terço médio. Além disso, a agitação ultrassônica não favoreceu melhor limpeza de parede em relação à irrigação convencional.

AIM: The aim of this study was to evaluate the efficacy of Sodium Hypochlorite associated or not with Tetrasodium EDTA in smear layer removal during root canal preparation. Additionally, to compare the cleaness of dentin walls after a final irrigation of Trisodium EDTA and Sodium Hypochlorite associated with Tetrasodium EDTA, activated or not by utrasonic. Methods: 40 mandibular premolars were used, which were divided in 2 groups (n=20). G1 the root canals were instrumented using Sodium hypochlorite and G2 using Sodium hypochlorite associated with Tetrasodium EDTA. Then, the dentin walls were analyzed by Scanning Electron Microscopy (SEM) to assess presence or not of smear-layer. After this step, it was performed a final irrigation of Trisodium EDTA and Sodium Hypochlorite associated with Tetrasodium EDTA, activated or not by utrasonic. Results: The was no significantly difference between the Sodium Hypochlorite and Sodium Hypochlorite associated with Tetrasodium EDTA during root canal preparation (P>0.05). Regarding the final irrigation, the Trisodium EDTA presented significantly difference when activated ultrasonic in the coronal and middle thirds (P<0.05). The association of Sodium Hypochlorite and Tetrasodium EDTA presented significantly difference only in the middle third without ultrasonic activation (P<0.05). In general, the Trisodium EDTA favoured better smear layer removal than Tetrasodium EDTA. Conclusion: The Trisodium EDTA favored a better smear layer ramoval than Tetrasodium EDTA, mainly in the middle third. In addition, ultrasonic activation improved the smear layer removal in comparison with conventional irrigation.

Evaluation of dentin desensitization protocols on the dentinal surface and their effects on the dentin bond interface.

OBJECTIVES: To evaluate the effect of desensitizing agent containing calcium phosphate nanoparticles on the bond strength of etch-and-rinse adhesive system (Scotchbond Multi-Purpose), presence of precipitate, dentinal tubule obliteration and hybrid layer formation in dentin in comparison with potassium nitrate plus sodium fluoride or strontium chloride compounds. METHODS: 150 bovine incisors were treated with (n = 10): G1, Desensibilize Nano P (Ca3(PO4)2+5%KNO3+0.9%NaF); G2, Desensibilize (10%SrCl2+5%KNO3); G3, Desensibilize KF2% (5%KNO3+0.2%NaF); G4, Ultra EZ (3%KNO3+0.25%NaF) and G5, no treated (control). Scanning electron microscopy was used to assess the incidence of precipitates (500×) and obliterated dentinal tubule counts (1.000×). The adhesive system was used after all desensitization treatments. The bond strength (n = 40) and the fracture pattern were evaluated. Confocal laser microscopy was used to quantify the hybrid layer formation in dentin. RESULTS: G1 and G2 presented higher adhesive system bond strength (MPa) than G4 and G5, however no significant differences were observed in comparison with G3. Cohesive fracture was frequently found: G1 (58.5%), G2 (51.3%) and G3 (43.8%). G1 showed the highest incidence of precipitates and the highest number of blocked dentinal tubules. G1 and G2 presented similar hybrid layer formation and the highest hybrid layer formation values. CONCLUSIONS: Desensibilize Nano P (G1) favored the bond strength of the adhesive system to dentin, increased the precipitation of residues, obliteration of dentinal tubules, and hybrid layer formation in comparison with other agents. CLINICAL RELEVANCE: Desensitizers promote dentin obliteration, however, may affect dentin bonding.

Physicochemical properties of calcium silicate-based formulations MTA Repair HP and MTA Vitalcem.

OBJECTIVE: This study aimed to analyze the following physicochemical properties: radiopacity, final setting time, calcium release, pH change, solubility, water sorption, porosity, surface morphology, and apatite-forming ability of two calcium silicate-based materials. MATERIAL AND METHODS: We tested MTA Repair HP and MTA Vitalcem in comparison with conventional MTA, analyzing radiopacity and final setting time. Water absorption, interconnected pores and apparent porosity were measured after 24-h immersion in deionized water at 37°C. Calcium and pH were tested up to 28 d in deionized water. We analyzed data using two-way ANOVA with Student-Newman-Keuls tests (p<0.05). We performed morphological and chemical analyses of the material surfaces using ESEM/EDX after 28 d in HBSS. RESULTS: MTA Repair HP showed similar radiopacity to that of conventional MTA. All materials showed a marked alkalinizing activity within 3 h, which continued for 28 d. MTA Repair HP showed the highest calcium release at 28 d (p<0.05). MTA Vitalcem showed statistically higher water sorption and solubility values (p<0.05). All materials showed the ability to nucleate calcium phosphate on their surface after 28 d in HBSS. CONCLUSIONS: MTA Repair HP and MTA Vitalcem had extended alkalinizing activity and calcium release that favored calcium phosphate nucleation. The presence of the plasticizer in MTA HP might increase its solubility and porosity. The radiopacifier calcium tungstate can be used to replace bismuth oxide.

Physicochemical properties of calcium silicate-based formulations MTA Repair HP and MTA Vitalcem

Abstract Objective This study aimed to analyze the following physicochemical properties: radiopacity, final setting time, calcium release, pH change, solubility, water sorption, porosity, surface morphology, and apatite-forming ability of two calcium silicate-based materials. Material and methods We tested MTA Repair HP and MTA Vitalcem in comparison with conventional MTA, analyzing radiopacity and final setting time. Water absorption, interconnected pores and apparent porosity were measured after 24-h immersion in deionized water at 37°C. Calcium and pH were tested up to 28 d in deionized water. We analyzed data using two-way ANOVA with Student-Newman-Keuls tests (p<0.05). We performed morphological and chemical analyses of the material surfaces using ESEM/EDX after 28 d in HBSS. Results MTA Repair HP showed similar radiopacity to that of conventional MTA. All materials showed a marked alkalinizing activity within 3 h, which continued for 28 d. MTA Repair HP showed the highest calcium release at 28 d (p<0.05). MTA Vitalcem showed statistically higher water sorption and solubility values (p<0.05). All materials showed the ability to nucleate calcium phosphate on their surface after 28 d in HBSS. Conclusions MTA Repair HP and MTA Vitalcem had extended alkalinizing activity and calcium release that favored calcium phosphate nucleation. The presence of the plasticizer in MTA HP might increase its solubility and porosity. The radiopacifier calcium tungstate can be used to replace bismuth oxide.

Comparison of two methods of irrigant agitation in the removal of residual filling material in retreatment.

The aim of this study was to compare the efficacy of passive ultrasonic irrigation and EasyClean for removing residual filling material in retreatment. Twenty-two maxillary lateral incisors with apical curvature were instrumented with ProTaper files and filled with Endofill using the lateral compactation technique. Removal of filling material was performed with Reciproc, Mtwo and ProDesign Logic 50/.01 files. The teeth were inserted in a silicone mould, which was placed in a metal muffle, and split to visualize the residual filling material. The samples were divided into two groups (n = 11) according to the irrigation protocol: Passive ultrasonic irrigation (PUI group) with 3 activations of 20 seconds and EasyClean (Easy Equipamentos Odontológicos, Belo Horizonte, Brazil) (EC group) used in continuous rotation with 3 activations of 20 seconds, both using NaOCl and EDTA. Environmental scanning electron microscopic images of the apical, middle, and cervical thirds were taken before and after the irrigant activation. The Kappa test was used to determine interexaminer agreement. Statistical analysis was performed using Kruskal-Wallis, Mann-Whitney, and Wilcoxon tests (p < 0.05). PUI and EC improved the removal of remnant filling material in all root canal thirds (p < 0.05). PUI and EC presented similar performance in the final step of retreatment (p > 0.05). No significant difference was observed in the removal of filling material in the apical, middle, and cervical thirds in both groups (p > 0.05). EasyClean in continuous rotary motion is useful in retreatment and was shown to be as effective as ultrasonic activation in the removal of remnant filling material.

Chemical-physical Properties and Apatite-forming Ability of Mineral Trioxide Aggregate Flow.

INTRODUCTION: This study aimed to analyze the chemical-physical properties, including pH, volumetric change, radiopacity, and apatite-forming ability in simulated body fluid, of a new tricalcium silicate material (MTA Flow; Ultradent Products Inc, South Jordan, UT). METHODS: MTA Flow was tested in comparison with MTA Angelus (Angelus, Londrina, PR, Brazil). The pH of soaking water was tested up to 168 hours in deionized water. In the solubility test, the root-end fillings of 20 acrylic teeth were scanned twice by micro-computed tomographic imaging before and after immersion in ultrapure water for 168 hours. In addition, using an aluminum step wedge, the radiopacity of each material was evaluated as recommended by international standards. The mean gray values of the test materials were measured using ImageJ software (National Institutes of Health, Bethesda, MD). The morphologic and chemical analyses of the material surface were performed using scanning electron microscopic energy-dispersive X-ray spectroscopic analysis after 28 days in Hank's balanced salt solution (HBSS). The data were analyzed using 2-way analysis of variance with the Student-Newman-Keuls test (P < .05). RESULTS: MTA Flow showed similar alkalizing activity to that of MTA Angelus. In the solubility test, both materials presented lower values without statistical differences. Both materials showed a marked alkalinizing activity within 3 hours, which continued for 168 hours. MTA Angelus showed statistically higher radiopacity values (P < .05). All materials showed the ability to nucleate calcium phosphate on their surface after 28 days in HBSS. CONCLUSIONS: MTA Flow showed remarkable alkalinizing capability, low solubility, good radiopacity, and the ability to form calcium phosphate deposits after being soaked in simulated body fluid, showing values similar to those of MTA Angelus.

Zinc Oxide Inhibits Dental Discoloration Caused by White Mineral Trioxide Aggregate Angelus.

INTRODUCTION: The aim of the study was to investigate the addition of variable amounts of zinc oxide to inhibit dental discoloration caused by mineral trioxide aggregate (MTA) Angelus. METHODS: MTA Angelus and MTA with additions of 5%, 15%, and 45% zinc oxide (ZnO) in weight were tested. The set cements were characterized by using a combination of scanning electron microscopy, energy dispersive spectroscopy, and x-ray diffraction. Radiopacity and setting time were analyzed according to American National Standards Institute/American Dental Association (57/2012) and American Society for Testing and Materials (C266-08). Volume change was evaluated by using micro-computed tomography analysis. The pH and calcium ion release were measured after 3 hours, 24 hours, and 28 days. Dental discoloration in contact with the cements was measured after 24 hours, 28 days, and 90 days. Biocompatibility to subcutaneous implantation in rats was verified after 30 and 60 days. RESULTS: Addition of ZnO did not alter significantly the radiopacity, setting time, volume change, pH, and biocompatibility compared with MTA Angelus (P > .05). Calcium ion release increased with addition of ZnO (P < .05). Proportions of 15% and 45% ZnO interfered in hydration. The 5% ZnO addition was sufficient to prevent the dental discoloration observed with MTA Angelus. CONCLUSIONS: The addition of 5%, 15%, or 45% zinc oxide to MTA Angelus inhibits dental discoloration without modifying the radiopacity, setting time, volume change, pH, and biocompatibility.

Evaluation of sealing ability, color alteration and surface morphology of MTA and Portland cement associated with different radiopacifiers and liquids / Avaliação da capacidade seladora, alteração de cor e de componentes superficiais do MTA e cimento Portland associado à diferentes radiopacificadores e diferentes líquidos

This study aimed to analyze the influence of two different vehicles for MTA manipulation on color alteration, chemical characteristics, and radiopacity after immersion in blood or distilled water (DW). In addition, some physical-chemical properties, volumetric solubility and bioactivity of new brands of calcium silicate cements such as MTA Repair HP, MTA Vitalcem and MTA Flow were compared with MTA Angelus. MTA Angelus mixed with 100% Distilled Water (DW) or 80% DW/20% propylene glycol (PG) as vehicles were placed into rubber rings and incubated at 37°C and 100% relative humidity. Color assessment and scanning electron microscopy/energy-dispersive spectroscopy (SEM/EDX) analysis were performed after setting and repeated after 7, 15, and 30 days after immersion in blood and DW. The data were analyzed by using Kruskal-Wallis followed by the Dunn test. The association of 80% DW/20% PG used as vehicle presented significantly lower color alterations compared with 100% DW, when immersed in blood (p < 0.05). All samples surfaces displayed loss of bismuth after immersion in both media and consequently a decrease in radiopacity was observed with significant results after 30 days. This study showed that ratio of 80% DW/20% PG as a vehicle for MTA Angelus results in a lower color alteration when in contact with blood. The physical-chemical properties such as radiopacity, calcium release, the pH change, solubility, water sorption, porosity, surface morphology, and bioactivity of MTA Repair HP and MTA Vitalcem were compared with MTA Angelus. Water absorption, interconnected pores and apparent porosity were measured after 24h-immersion in DW at 37ºC. Calcium and pH were tested up to 28d in DW. Morphological and chemical analyses of the material surfaces were performed by using ESEM-EDX after 28d in HBSS. All the materials showed good bioactivity after 28d in HBSS. The data were analyzed by using two-way ANOVA followed by the RM Student-Newman-Keuls test (p<0.05). MTA Repair HP and MTA Vitalcem had some positives properties, such as extended alkalinizing activity and calcium release that favored the bioactivity. However, MTA Vitalcem showed scant radiopacity, long setting time and high solubility. The radiopacifier Calcium Tungstate, present in MTA Repair HP can be used to replace the traditional Bismuth Oxide. In relation to the comparison between MTA Angelus and MTA Flow, it was analyzed the pH, volumetric change, radiopacity and bioactivity. In the volumetric change test, the root-end fillings of 20 acrylic teeth with both materials were scanned twice by a Micro- CT, before and after immersion in DW for 168 h. The morphological and bioactivity of the materials were performed by using SEM-EDX after 28d in HBSS. The data were analyzed by using two-way ANOVA followed by the RM Student-Newman-Keuls test (p<0.05). MTA Angelus showed statistically higher radiopacity values (p<0.05). the results pointed that the new cement MTA Flow showed good physical-chemical characteristics and bioactivity, showing values similar to those of MTA Angelus. (AU)

O objetivo do estudo foi analisar a influência de dois diferentes veículos utilizados na manipulação do MTA em relação a alteração de cor, características superficiais e radiopacidade, antes de depois do contato com sangue ou Água Destilada (AD). Adicionalmente, foram analisadas as propriedades físico-quimicas, solubilidade volumétrica e a bioatividade de novas marcas comerciais de cimentos de silicato de cálcio como MTA Repair HP, MTA Vitalcem e MTA Flow comparados com o MTA Angelus. Foram realizadas associações do MTA Angelus com 100% de Água Destilada (AD) e outra com 80% de AD e 20% de Propilenoglicol (PG) como veículos e, após isso, estas foram inseridas em anéis de borracha e encubadas a 37ºC e 100% de humidade. A análise de cor e realização do escaneamento da amostra em microscópio eletrônico de varredura (MEV) juntamente com a espectroscopia de energia dispersiva (EDX) foram realizadas após a presa e depois de 7, 15 e 30 dias após a imersão em sangue ovino e água destilada. Os dados foram submetidos aos testes não paramétricos de Kruskal-Wallis e Dunn. A associação com o veículo de 80% AD com 20% de PG apresentou alteração de cor significativamente menor quando comparada com o veículo de 100% de AD quando imersos em sangue (p < 0.05). Em todas as amostras a análise superficial comprovou a perda de partículas de bismuto durante a imersão nos diferentes líquidos e consequentemente a redução da radiopacidade apresentando resultados significativos após 30 dias. Esse estudo demonstrou que o uso do veículo 80% de AD com 20% de PG no MTA Angelus apresentou menor alterações de cor quando em contato com sangue. As propriedades físico químicas como radiopacidade, liberação de cálcio, pH, solubilidade, absorção de água, porosidade, análise das características superficiais e bioatividade dos cimentos MTA Repair HP e MTA Vitalcem foram comparadas com as do MTA Angelus. A absorção de água e a porosidade aparente foram analisadas 24h após a imersão dos espécimes em AD a 37ºC. A liberação e cácio e o pH foram anaisados após 28d de imersão em AD. As características superficiais e a Bioatividade foram analisadas em MEV/EDX após 28 dias de imersão em HBSS. Os dados foram submetidos aos testes de two-way ANOVA seguido por RM Student-Newman-Keuls (p<0.05). Todos os materiais apresentaram boa bioatividade após 28 dias de imersão em HBSS. O MTA Repair HP e o MTA Vitalcem apresentaram boa atividade alcalinizante e liberação de ions cálcio favorecendo a bioatividade. Entretanto o MTA Vitalcem mostrou baixa radiopacidade, longo tempo de presa e alta solubilidade. O radiopacificador Tungstato de Cálcio, utilizado no MTA Repair HP pode ser usado como substituto do tradicional óxido de bismuto. Em relação a comparação entre o MTA Angelus e o MTA Flow, foram realizados as analises de pH, alteração volumétrica, radiopacidade e bioatividade. Em relação a alteração volumétrica, 20 retro-cavidades de dentes de acrílico preenchidas com os materiais foram escaneadas duas vezes em um aparelho de Micro-CT antes e após a imersão por 168h em AD. As características superficiais e a bioatividade foram realizadas por MEV/EDX depois de 28d de imersão em HBSS. Os dados foram submetidos aos testes de two-way ANOVA seguido por RM Student-Newman-Keuls (p<0.05). O MTA Angelus apresentou estatisticamente maior radiopacidade (p<0.05). Os resultados apontaram que o novo cimento MTA Flow apresentou boas características físico-quimicas e bioatividade similares ao MTA Angelus. (AU)

Influence of the instrument used for cervical preflaring on the precision of 2 Eletronic Apex Locators / Influência do instrumento utilizado no preparo cervical na precisão de 2 localizadores apicais eletrônicos

ABSTRACT Objective: This study was aimed at evaluating the influence of cervical preflaring using LA-Axxes No. 1 bur (SybronEndo, Glendora, USA) or S1 and SX ProTaper files (Dentsply Maillefer, Ballaigues, Switzerland) on the accuracy of the Electronic Apex Locators (EALs): Root ZX mini (J. Morita Corporation, Tokyo, Japan), and Joypex 5 (Denjoy, Changsha, China). Methods: Thirty mandibular incisors were accessed, and the root canal length (RCL) was determined with a K-file #15, with the aid of a stereo microscope. Afterwards, the specimens were divided into 2 groups (n = 15) referring to the cervical preflaring with LA-Axxess or ProTaper files. The teeth were embedded in alginate and the RCL was determined by the EALs before and after preflaring. Data were classified into: accurate, if the difference in RCL measurement were ≤0.05 mm; and inaccurate, if the difference were >0.5 mm or beyond the RCL. Results: McNemar's test (α<0.05) was used to detect differences in the accuracy of the EALs before and after each preflaring with different instruments, and to detect difference in accuracy among devices. No differences were found concerning the accuracy of the EALs (P > 0.05) after the cervical preflaring, regardless of the used instrument. Conclusion: The preflaring procedure increased the number of accurate measurements for both EALs, with statistical difference for Joypex 5 when the preflaring was performed with LA-Axxess. However, after the cervical preflaring, the EALs showed similar accuracy, regardless of the used instrument.

RESUMO Objetivo: Avaliar a influência do preparo cervical utilizando a broca LA-Axxess nº 1 (SybronEndo, Glendora, EUA) ou os instrumentos ProTaper S1 e SX (Dentsply Maillefer, Ballaigues, Suíça) na precisão dos Localizadores Apicais Eletrônicos (LAEs): Root ZX mini (J. Morita Corporation, Tóquio, Japão) e Joypex 5 (Denjoy, Changsha, China). Métodos: Trinta incisivos inferiores foram acessados e o comprimento do canal radicular (CCR) determinado com uma lima K #15 com o auxílio de um estereomicroscópio. Em seguida, os dentes foram distribuídos em dois grupos (n=15) referentes ao preparo cervical com LA-Axxess ou instrumentos ProTaper. Os dentes foram incluídos em alginato e o CCR determinado pelos LAEs antes e após o preparo cervical. Os dados foram classificados em: precisos, se a diferença na medida do CCR era ≤ 0,05 mm; e imprecisos, se a diferença era >0,5 mm ou estava além do CCR. Resultados: O teste de McNemar (α<0.05) foi utilizado para detectar diferenças na precisão dos LAEs antes e após o preparo com os diversos instrumentos, e para detectar diferenças na precisão entre os aparelhos. Não foram identificadas diferenças na precisão entre os dois LAEs (P>0,05) após o preparo cervical, indiferente do instrumento utilizado. Conclusão: O preparo cervical aumentou o número de medições precisas dos LAEs, com diferença estatística para Joypex 5 após o uso da LA-Axxess, contudo os aparelhos apresentaram precisão similar após o preparo cervical, indiferente do instrumento utilizado.

Physical and Chemical Properties and Subcutaneous Implantation of Mineral Trioxide Aggregate Mixed with Propylene Glycol.

INTRODUCTION: The aim of this study was to evaluate the physical, chemical, and biological properties of mineral trioxide aggregate (MTA) mixed with 80% distilled water and 20% propylene glycol (PG) compared with MTA mixed with distilled water only. METHODS: Flowability, film thickness, and solubility were analyzed according to American National Standards Institute/American Dental Association specification 57/2000. Initial and final setting times were assessed according to American Society for Testing and Materials specification C266/08. Porosity was assessed by using mercury intrusion porosimetry after 1 and 28 days of hydration, and the pH and calcium ion release were assessed after 3, 24, 72, and 168 hours. For the tissue reaction, the cements were implanted in 24 albino rats (2 groups, n = 12). An analysis of the inflammatory infiltrate was performed after 15, 30, and 60 days. RESULTS: MTA + PG exhibited lower film thickness and higher final setting time. No differences were verified for flowability (P > .05). MTA + PG showed high porosity at 1 day of hydration (P < .05). All the test cements demonstrated an alkaline pH. Microscopic analysis of the specimens revealed neoformation of connective tissue in contact with the cements. CONCLUSIONS: The introduction of PG as a mixing vehicle alters the physical and chemical properties of MTA and is biologically acceptable.

Influência do tipo de instrumento empregado para agitação ultrassônica na capacidade de remoção da smear layer / Influence of the type of instrument used in passive ultrasonic irrigation on the smear layer removal capacity

Introdução: o objetivo do presente estudo foi avaliar a capacidade de remoção da smear layer de limas manuais de aço inoxidável e de NiTi e de fio ortodôntico de NiTi, ativados pelo ultrassom. Métodos: 50 canais de raízes palatinas de molares superiores foram dilatados, no terço cervical, com a broca Laxxess 35 e, no terço apical, com o sistema ProTaper, até o instrumento F4, no comprimento real de trabalho. Os canais foram irrigados com hipoclorito de sódio a 1% e divididos em cinco grupos: GI = EDTA + ultrassom por 1 minuto com lima 15 do tipo K de aço inoxidável; GII = EDTA + ultrassom por 1 minuto com lima tipo K 15 de NiTi; GIII = EDTA + ultrassom por 1 minuto com fio ortodôntico #25 x 11 de NiTi; GIV = EDTA por 3 minutos sem agitação com ultrassom; GV = sem EDTA nem ultrassom. Posteriormente, cada raiz foi seccionada longitudinalmente e uma hemissecção foi metalizada e analisada em microscópio eletrônico de varredura, sendo feitas imagens de cada uma delas, nos três terços, estipulando-se os seguintes escores: 0 = nenhuma camada de detritos dentinários, com túbulos dentinários limpos e abertos; 1 = camada moderada de detritos dentinários; 2 = camada espessa de detritos dentinários, cobrindo a superfície dos túbulos dentinários. Os dados foram comparados estatisticamente. Resultados: após observar a smear layer nos três terços, verificou-se que todos os grupos que usaram o EDTA se diferenciaram estatisticamente (p < 0,05) do grupo sem EDTA. Não houve, porém, diferenças significativas entre os grupos com agitação ultrassônica e o grupo de EDTA sem ultrassom. Não houve diferenças significativas (p < 0,05) entre os três instrumentos empregados. Conclusão: o uso do EDTA favoreceu a remoção da smear layer. A ativação ultrassônica do EDTA por 1 minuto, independentemente do instrumento empregado, favoreceu a obtenção de paredes mais limpas.

Color stability, radiopacity, and chemical characteristics of white mineral trioxide aggregate associated with 2 different vehicles in contact with blood.

INTRODUCTION: Discoloration of mineral trioxide aggregate (MTA) can be exacerbated by the interaction of the cement with body fluids such as blood. This study aimed to analyze the color alteration, chemical characteristics, and radiopacity of MTA manipulated with 2 different vehicles after immersion in blood or distilled water (DW). METHODS: MTA mixed with 100% DW or 80% DW/20% propylene glycol (PG) as vehicles were placed into rubber rings and incubated at 37°C and 100% relative humidity until set. Color assessment and scanning electron microscopy/energy-dispersive spectroscopy analysis were performed after setting and repeated after 7, 15, and 30 days after immersion in blood and DW. Statistical analysis for color alteration and radiopacity was performed using nonparametric Kruskal-Wallis and Dunn tests (P < .05). RESULTS: When 80% DW/20% PG was used as the vehicle, significantly lower color alterations were observed for all time periods compared with 100% DW when immersed in blood (P < .05). All surfaces displayed morphologic changes after immersion in both media because of loss of bismuth. A decrease in radiopacity was observed over time in all groups, with a statistically significant difference after 30 days for groups DW immersed in blood and 80% DW/20% immersed in both media (P < .05). CONCLUSIONS: The ratio of 80% DW/20% PG as a vehicle for MTA results in a lower color alteration when in contact with blood.

Accuracy evaluation of three electronic apex locators in teeth with immature apices

Introduction and Objective: The aim of this randomized controlled study was to evaluate the accuracy of Root ZX, iPex and YS-RZ-A apex locators in tooth with incomplete apices. Material and methods: Thirty human mandibular pre-molars without dental caries, fracture and with 1-3mm apical diameter and ¾ of root development stage were used. After coronal access, tooth length was determined with the visualization of a K-file, compatible with the root canal diameter, at the apex. To determine the root canal length using electronic methods, the teeth were included in alginate. The 30 teeth were measured with the three apex locators until achieving the apex foramen. During the measurement, the canals were inundated with 1% sodium hypochlorite. Statistical analysis was performed using Qui-square test (p < 0.05). Results: The Root ZX apex locator showed the higher accuracy (53.3%), with statistical difference in relation to iPex apex locator (33.3%) and YS-RZ-A apex locator (26.7%) (p < 0.05). Regarding the security limit of ±1 mm, the Root ZX apex locator did not show statistical difference in comparison with iPex apex locator (p > 0.05), but both were statistically different in relation to YS-RZ-A apex locator (p < 0.05). Conclusion: The results showed that all the studied apex locators were efficient in determining the root canal length in tooth with incomplete apex, considering the tolerance of ±1 mm. The Root ZX apex locator showed the highest accuracy with 100% of agreement.

Microscopic analysis of the quality of obturation and physical properties of MTA Fillapex.

This study analyzed the quality of obturation and physical properties of MTA Fillapex and AH Plus sealer. A sample of 30 human maxillary central incisors were instrumented with Protaper until a F5 (50/05) file. Both sealers were mixed with Rhodamine-B dye to allow visualization on a confocal laser-scanning microscope (CLSM). Next, the canals were filled using the single cone technique. After setting, all samples were sectioned at 2, 4, and 6 mm from the apex. CLSM was used to analyze the gaps and sealer penetration into the dentinal tubules. All samples were scanned 10 µm below the dentin surface and images were recorded at 100× magnification using the fluorescent mode. Additionally, the solubility, flowability and setting time of the sealers were evaluated. All the measured quantities of the examined materials were evaluated for significant differences by means of statistical analysis. The CLSM analysis of the MTA Fillapex showed the highest percentage of gaps at all sections (P = 0.0001). Physical tests revealed adequate properties for both sealers except for a higher solubility of the MTA Fillapex (P = 0.0001). The MTA Fillapex presented flowability and intratubular penetration similar to the AH Plus. Nevertheless, the MTA Fillapex sealer presented a higher solubility and considerable quantity of gaps between the sealer/dentin interface in relation to the AH Plus sealer. Clinicians must take into consideration, the quality of endodontic sealers as it is essential in the outcome of the root canal filling.

Antimicrobial activity and synergism of lactoferrin and lysozyme against cariogenic microorganisms.

The present study evaluated the antimicrobial in vitro effects of the salivary proteins lactoferrin and lysozyme on microorganisms involved in the carious process, obtaining their minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Streptococcus mutans (ATCC 25175) and Lactobacillus casei (ATCC 7469) were submitted to broth macrodilution of lysozyme at 80 mg/mL and lactoferrin at 200 mg/mL. The tubes were read in a spectrophotometer after they had been incubated at 37 °C for 18 h, in a carbon dioxide chamber, in order to read the MIC. A new subculture was carried on agar plates to obtain the MBC. The agar diffusion method was also tested, using BHI agar with 100 µL of the standardized microbial inocula. Filter-paper disks soaked in 10 µL of the solutions lactoferrin (200 µg/mL) and lysozyme (80 µg/mL) were placed on the agar surface. Inhibition halos were not observed on the plates, showing the absence of the antimicrobial effects of these proteins in this method. The bactericidal and bacteriostatic effects of lysozyme on L. casei were 50.3 mg/mL and 43.1 mg/mL respectively. The bactericidal and bacteriostatic effects on S. mutans were 68.5 mg/mL and 58.7 mg/mL. Lactoferrin did not induce any inhibitory effects on any microorganism, even in the concentration of 200 mg/mL. There was not a synergic antimicrobial effect of proteins, when they were tested together, even in the concentration of 42.8 mg/mL of lysozyme and 114 mg/mL of lactoferrin (the highest values evaluated). S. mutans and L. casei were only inhibited by lysozyme, not affected by lactoferrin and by the synergic use of both proteins.