Evaluation of cutting ability and plastic deformation of reciprocating files.

This in vitro study evaluated the cutting ability of reciprocating files and the deformations caused by their multiple use. Five Reciproc® R25 files were divided into five groups for 10 simulated root canal preparations each. The resin blocks were weighed and photographed (12.5X and 20X) before and after preparation. The canals were prepared according to the manufacturer's instructions. Enlargement of the root canals was evaluated by comparison of pre- and post-preparation images using a computer software. The preoperative and postoperative weight differences determined the cutting ability of repeatedly used instruments. The data were analyzed using Lilliefors and Friedman statistical tests. The cutting ability and enlargement of the canals gradually decreased after each use, with significant differences observed at the 8th and 9th repetitions, respectively. There was no evidence of file deformation. The cutting ability and enlargement of the simulated canals gradually decreased when a reciprocating file was used up to 10 times.

Evaluation of cutting ability and plastic deformation of reciprocating files

Abstract This in vitro study evaluated the cutting ability of reciprocating files and the deformations caused by their multiple use. Five Reciproc® R25 files were divided into five groups for 10 simulated root canal preparations each. The resin blocks were weighed and photographed (12.5X and 20X) before and after preparation. The canals were prepared according to the manufacturer’s instructions. Enlargement of the root canals was evaluated by comparison of pre- and post-preparation images using a computer software. The preoperative and postoperative weight differences determined the cutting ability of repeatedly used instruments. The data were analyzed using Lilliefors and Friedman statistical tests. The cutting ability and enlargement of the canals gradually decreased after each use, with significant differences observed at the 8th and 9th repetitions, respectively. There was no evidence of file deformation. The cutting ability and enlargement of the simulated canals gradually decreased when a reciprocating file was used up to 10 times.

Applying liquid chromatography-tandem mass spectrometry to assess endodontic sealer microleakage.

The objective of this study was to describe a new method for the quantitative analysis of a microleakage of endodontic filling materials. Forty extracted single-rooted teeth were randomly divided into three experimental groups. After root canal shaping, the experimental groups were filled using the lateral condensation technique with the Epiphany system (G1), with gutta-percha + Sealapex (G2), and with gutta-percha + AH Plus (G3). Each root was mounted on a modified leakage testing device, and caffeine solution was used as a tracer (2000 ng mL-1, pH 6.0), applied in the coronal direction towards the tooth apex, creating a hydrostatic pressure of 2.55 kPa. Presence of caffeine in the receiving solution was measured after 10, 30, and 60 days, using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). None of the groups presented microleakage at 10 days. At 30 days, G2 and G3 showed similar infiltration patterns (means: 16.0 and 13.9 ng mL-1, respectively), whereas G1 showed significantly higher values (mean: 105.2 ng mL-1). At 60 days, leakage values were 182.6 ng mL-1 for G1, 139.0 ng mL-1 for G2, and 53.5 ng mL-1 for G3. AH Plus showed the best sealing ability and HPLC-MS/MS showed high sensitivity and specificity for tracer quantification.

Penetration of a resin-based filling material into lateral root canals and quality of obturation by different techniques.

The aim of this study was to evaluate the penetration of a resin/polyester polymer-based material (Resilon Real Seal; SybronEndo Corp., Orange, USA) into simulated lateral canals, and the quality of obturations by different techniques. A total of 30 standardized simulated canals were divided into three groups according to the technique of obturation used: MS (McSpadden), SB (SystemB/Obtura II), and LC (Lateral Condensation). To analyze the penetration of the filling material, the simulated canals were digitalized and the images were analyzed using the Leica QWIN Pro v2.3 software. The data of the middle and apical thirds were separately submitted to analysis of variance (ANOVA), followed by the Tukey's test for the comparison of the techniques. Results showed a significant difference (p < 0.05) between groups (LC < SB) in the middle third, and a significant difference (p < 0.05) between groups (LC < SB and MS < SB) in the apical third. To analyze the quality of the obturations, the canals were radiographed and evaluated by three examiners. The Kappa test on interexaminer agreement and the nonparametric Kruskal-Wallis test indicated no significant difference between filling techniques. It was concluded that Resilon achieves greater levels of penetration when associated with thermoplastic obturation techniques.

Influence of calcium hydroxide dressing and two irrigants on the filling of artificial lateral canals.

CONTEXT: This study was carried out on the assumption that calcium hydroxide [Ca(OH) 2 ] dressing and irrigants may influence the obturation of lateral canals. AIMS: To evaluate the influence of 2.5% sodium hypochlorite (NaOCl), 2% chlorhexidine (CHX) gel and Ca(OH) 2 on the filling of artificial lateral canals. SETTINGS AND DESIGN: Ex vivo quantitative laboratory study. MATERIALS AND METHODS: Forty-two human mandibular premolars were selected. After cavity access, six lateral canals were performed, two in each root section, one mesial and one on the distal root surface. After preparation, the specimens were randomly divided into four groups: Group I: Under irrigation with 2% CHX and saline solution and with intracanal dressing Ca(OH) 2 paste; Group II: The same preparation as Group I, but without Ca(OH) 2 ; Group III: Under irrigation with 2.5% NaOCl without Ca(OH) 2 ; and Group IV: The same preparation as Group III, but with Ca(OH) 2 . Two teeth without intracanal dressing were used as negative controls. Lateral condensation technique was performed. Then, digital radiographic images were obtained. STATISTICAL ANALYSIS USED: Data were analyzed using SPSS 17.0, submitted to Kappa (reliability between examiners) and Kruskal-Wallis test. RESULTS: No statistical difference was registered between Groups II and III in all root sections (P > 0.05), but it was observed between Groups I and IV (P < 0.05), except on the apical section (P > 0.05). In all sections, the Group I filled more artificial lateral canals than in Group IV. CONCLUSIONS: The irrigants tested had no influence on the filling of artificial lateral canals. Nevertheless, intracanal dressing of Ca(OH) 2 influenced this filling.

Applying liquid chromatography-tandem mass spectrometry to assess endodontic sealer microleakage

The objective of this study was to describe a new method for the quantitative analysis of a microleakage of endodontic filling materials. Forty extracted single-rooted teeth were randomly divided into three experimental groups. After root canal shaping, the experimental groups were filled using the lateral condensation technique with the Epiphany system (G1), with gutta-percha + Sealapex (G2), and with gutta-percha + AH Plus (G3). Each root was mounted on a modified leakage testing device, and caffeine solution was used as a tracer (2000 ng mL-1, pH 6.0), applied in the coronal direction towards the tooth apex, creating a hydrostatic pressure of 2.55 kPa. Presence of caffeine in the receiving solution was measured after 10, 30, and 60 days, using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). None of the groups presented microleakage at 10 days. At 30 days, G2 and G3 showed similar infiltration patterns (means: 16.0 and 13.9 ng mL-1, respectively), whereas G1 showed significantly higher values (mean: 105.2 ng mL-1). At 60 days, leakage values were 182.6 ng mL-1for G1, 139.0 ng mL-1 for G2, and 53.5 ng mL-1 for G3. AH Plus showed the best sealing ability and HPLC-MS/MS showed high sensitivity and specificity for tracer quantification.

Penetration of a resin-based filling material into lateral root canals and quality of obturation by different techniques

The aim of this study was to evaluate the penetration of a resin/polyester polymer-based material (Resilon Real Seal; SybronEndo Corp., Orange, USA) into simulated lateral canals, and the quality of obturations by different techniques. A total of 30 standardized simulated canals were divided into three groups according to the technique of obturation used: MS (McSpadden), SB (SystemB/Obtura II), and LC (Lateral Condensation). To analyze the penetration of the filling material, the simulated canals were digitalized and the images were analyzed using the Leica QWIN Pro v2.3 software. The data of the middle and apical thirds were separately submitted to analysis of variance (ANOVA), followed by the Tukey’s test for the comparison of the techniques. Results showed a significant difference (p < 0.05) between groups (LC < SB) in the middle third, and a significant difference (p < 0.05) between groups (LC < SB and MS < SB) in the apical third. To analyze the quality of the obturations, the canals were radiographed and evaluated by three examiners. The Kappa test on interexaminer agreement and the nonparametric Kruskal-Wallis test indicated no significant difference between filling techniques. It was concluded that Resilon achieves greater levels of penetration when associated with thermoplastic obturation techniques.

Influence of Apical Patency and Cleaning of the Apical Foramen on Periapical Extrusion in Retreatment

This study evaluated the influence of apical patency, root filling removal technique and cleaning of the apical foramen, concerning the amount of debris extruded during root canal retreatment. Forty mandibular incisors were randomly assigned to 4 groups - GIM (n=10), GIIM (n=10), GIPT (n=10) and GIIPT (n=10), which were named according to leaving (I) or not (II) apical patency during canal preparation and filling removal technique (manual - M or ProTaper system - PT). After filling material removal, each specimen of each group had the apical foramen cleaned by sizes 15, 20 and 25 instruments, generating 12 subgroups: GIM15, GIM20, GIM25, GIIM15, GIIM20, GIIM25, GIPT15, GIPT20, GIPT25, GIIPT15, GIIPT20 and GIIPT25. Extruded filling debris was collected by a Milipore filtration system, an HV-durapore, 0.45 µm pore filter with a 25 mm diameter. The filters were weighed before and after the collection on an analytical scale (10–5 g), and the difference was calculated. The mean weight of extruded filling debris was analyzed statistically by Kruskal-Wallis and Friedman ANOVA tests (α=0.05). The mean values found in the groups (in mg) were: GIM (0.95±0.94), GIIM (0.47±0.62), GIPT (0.30±0.31) and GIIPT (0.32±0.44). There was no statistically significant difference among any of the groups or subgroups (p>0.05). ProTaper provided the smallest amount of extruded filling material, regardless of presence or absence of apical patency, followed by manual technique, without and with apical patency. Additional amounts of debris were collected during cleaning of the apical foramen, regardless of the instrument, presence/absence of patency or root filling removal technique.

Este estudo verificou a influência da patência apical, técnica de desobturação e limpeza foraminal na quantidade de material sólido extruído, durante retratamento endodôntico. Quarenta incisivos inferiores foram divididos aleatoriamente em quatro grupos - GIM (n=10), GIIM (n=10), GIPT (n=10) e GIIPT (n=10) - nomeados de acordo com a realização (I) ou não (II) de patência apical durante o preparo de canais e a técnica de desobturação - manual (M) ou sistema ProTaper (PT). Após a desobturação, realizou-se a limpeza foraminal em cada espécime de todos os grupos com instrumentos #15, #20 e #25, gerando 12 subgrupos: GIM15, GIM20, GIM25, GIIM15, GIIM20, GIIM25, GIPT15, GIPT20, GIPT25, GIIPT15, GIIPT20 e GIIPT25. O material sólido extruído foi coletado pelo sistema de filtração Millipore®, com filtros de 0,45 µm de poro e 25 mm de diâmetro. Os filtros foram pesados antes e após a coleta, em balança analítica de precisão (10–5g), e as diferenças foram calculadas. Os valores médios encontrados (em mg) foram: GIM (0,95±0,94), GIIM (0,47±0,62), GIPT (0,30±0,31) e GIIPT (0,32±0,44), sem diferença estatística entre quaisquer dos grupos ou subgrupos (p>0,05). O sistema Protaper proporcionou a menor quantidade de material sólido extruído, independente da presença ou não de patência apical seguidos da técnica manual sem e com patência apical. Quantidades adicionais foram coletadas durante a limpeza foraminal, independente do instrumento utilizado, da presença ou não da patência apical ou da técnica de desobturação.

Performance of RaCe instrumentation system in curved root canals: a comprehensive analysis by three study methods.

In this study, curved maxillary molar root canals were instrumented with RaCe rotary system to evaluate: 1. the occurrence of canal transportation using a radiographic platform; 2. the action of the instruments on the dentin walls, centering ability and canal enlargement by analysis of digital images; and the percentage of regular dentin surfaces and debris within the canal by histological analysis. Ten mesiobuccal roots of extracted human maxillary molars were embedded in acrylic resin and sectioned at the middle and apical thirds. Root canal shaping was performed using the RaCe rotary system at 250 rpm and 1 Ncm torque. Each instrument set was used five times according to a crown-down technique in the following sequence: 40/0.10, 35/0.08, 25/0.06, 25/0.04, 25/0.02 (working length - WL), 30/0.02 (WL) and 35/0.02 (WL). Each instrument was inserted until resistance was felt and then pulled back, followed by brushing movements towards all canal walls. Each specimen was assessed by three study methods: radiographic platform, digitized image assessment and histological analysis. The radiographic platform showed lack of apical transportation. No statistically significant difference (Wilcoxon test, p>0.05) was found between the middle and apical thirds regarding instrument action on dentin walls, centering ability, area of root canal enlargement, percentage of regular dentin surfaces and debris within the root canal. It may be concluded that RaCe system is a suitable method for the preparation of curved root canals, regarding the maintenance of root canal original path, action on dentin walls, canal enlargement and removal of debris from the root canal lumen.

Performance of RaCe Instrumentation System in Curved Root Canals: A Comprehensive Analysis by Three Study Methods

In this study, curved maxillary molar root canals were instrumented with RaCe rotary system to evaluate: 1. the occurrence of canal transportation using a radiographic platform; 2. the action of the instruments on the dentin walls, centering ability and canal enlargement by analysis of digital images; and the percentage of regular dentin surfaces and debris within the canal by histological analysis. Ten mesiobuccal roots of extracted human maxillary molars were embedded in acrylic resin and sectioned at the middle and apical thirds. Root canal shaping was performed using the RaCe rotary system at 250 rpm and 1 Ncm torque. Each instrument set was used five times according to a crown-down technique in the following sequence: 40/0.10, 35/0.08, 25/0.06, 25/0.04, 25/0.02 (working length - WL), 30/0.02 (WL) and 35/0.02 (WL). Each instrument was inserted until resistance was felt and then pulled back, followed by brushing movements towards all canal walls. Each specimen was assessed by three study methods: radiographic platform, digitized image assessment and histological analysis. The radiographic platform showed lack of apical transportation. No statistically significant difference (Wilcoxon test, p>0.05) was found between the middle and apical thirds regarding instrument action on dentin walls, centering ability, area of root canal enlargement, percentage of regular dentin surfaces and debris within the root canal. It may be concluded that RaCe system is a suitable method for the preparation of curved root canals, regarding the maintenance of root canal original path, action on dentin walls, canal enlargement and removal of debris from the root canal lumen.

O objetivo do presente estudo foi verificar a presença de desvio apical por meio da plataforma radiográfica, avaliar a ação dos instrumentos, centralização do preparo e ampliação por meio de imagens digitais do canal e calcular a porcentagem de superfícies regulares e presença de debris por meio da análise histológica. Dez raízes mésiovestibulares de molares superiores extraídos foram incluídos em blocos de resina e seccionados no terço médio e apical. O preparo do canal foi feito empregando o sistema RaCe, a 250 rpm e torque de 1 Ncm. Cada sistema rotatório foi usado 5 vezes no sentido coroa-ápice na seguinte sequência: 40/0.10, 35/0.08, 25/0.06, 25/0.04, 25/0.02 (comprimento de trabalho - CT), 30/0/02 (CT) e 35/0/02 (CT). Cada amostra foi avaliada por 3 métodos de estudo: plataforma radiográfica, imagem digital e análise histológica. A plataforma radiográfica mostrou ausência de transporte apical. Em relação à ação dos instrumentos sobre as paredes dentinárias, centralização do preparo, ampliação, porcentagem de superfícies regulares e presença de debris, o teste estatístico de Wilcoxon não mostrou diferença significativa entre os terços apical e médio. O sistema RaCe se mostrou adequado para o preparo de canais radiculares curvos em relação à manutenção do trajeto original do canal, ação sobre as paredes dentinárias, ampliação e remoção de debris da luz do canal radicular.

Influence of apical patency and cleaning of the apical foramen on periapical extrusion in retreatment.

This study evaluated the influence of apical patency, root filling removal technique and cleaning of the apical foramen, concerning the amount of debris extruded during root canal retreatment. Forty mandibular incisors were randomly assigned to 4 groups - GIM (n=10), GIIM (n=10), GIPT (n=10) and GIIPT (n=10), which were named according to leaving (I) or not (II) apical patency during canal preparation and filling removal technique (manual - M or ProTaper system - PT). After filling material removal, each specimen of each group had the apical foramen cleaned by sizes 15, 20 and 25 instruments, generating 12 subgroups: GIM15, GIM20, GIM25, GIIM15, GIIM20, GIIM25, GIPT15, GIPT20, GIPT25, GIIPT15, GIIPT20 and GIIPT25. Extruded filling debris was collected by a Milipore filtration system, an HV-durapore, 0.45 µm pore filter with a 25 mm diameter. The filters were weighed before and after the collection on an analytical scale (10-5 g), and the difference was calculated. The mean weight of extruded filling debris was analyzed statistically by Kruskal-Wallis and Friedman ANOVA tests (α=0.05). The mean values found in the groups (in mg) were: GIM (0.95 ± 0.94), GIIM (0.47 ± 0.62), GIPT (0.30 ± 0.31) and GIIPT (0.32 ± 0.44). There was no statistically significant difference among any of the groups or subgroups (p>0.05). ProTaper provided the smallest amount of extruded filling material, regardless of presence or absence of apical patency, followed by manual technique, without and with apical patency. Additional amounts of debris were collected during cleaning of the apical foramen, regardless of the instrument, presence/absence of patency or root filling removal technique.

Preenchimento de canais radiculares com pastade hidróxido de cálcio, utilizando-se propulsor de Lentulo, em diferentes velocidades / Root canal filling with calcium hydroxide paste using lentullo spiral at different speeds

Objetivo: este estudo analisou a efetividade do preenchimento do canal radicular com pasta de hidróxido empregando o propulsor de Lentulo, acionado em diferentes velocidades.Métodos: trinta pré-molares inferiores tiveram seus canais radiculares preparados até o instrumento #50 e divididos aleatoriamente em três grupos. Pasta de hidróxido de cálcio preparada com solução fisiológica foi inserida nos canais radiculares empregando-se um propulsor de Lentulo, acionado com velocidades de 5.000 rpm (G1), 10.080 rpm(G2) e 15.000 rpm (G3). A densidade óptica foi determinada utilizando-se o sistema de radiografia digital (Kodak Dental RGV-5000). Resultados: a maior densidade óptica obtida no terço apical foi no G3, e nos terços médio e cervical no G1. Por meio do teste Kruskal-Wallis-Anova, observou--se diferença estatística (p<0,05) entre o G1 e G3 no terço apical, e G1 e G2 no terço médio, mas nenhuma diferença estatística foi observada no terço cervical (p>0,05).Conclusão: velocidades diferentes são necessárias para o correto preenchimento de canais radiculares com pasta de hidróxido de cálcio. A velocidade de 15.000 rpm foi mais efetiva no preenchimento do terço apical e a velocidade de 5.000 rpm foi mais efetiva no preenchimento dos terços médio e cervical.

Objective: This study analyzed the effectiveness of fillingthe root canal with calcium hydroxide paste using the Lentulospiral at different speeds. Methods: Thirty mandibularpremolars after root canal preparation were divided in threegroups. Calcium hydroxide paste was inserted in the rootcanals with a Lentulo spiral at 5,000 rpm (G1), 10,000 rpm(G2) and 15,000 rpm (G3). The optical density was determinedby the use of the digital radiography system KodakDental RGV-5000. Results: The highest optical densityobtained in the apical third was in G3 and in the middle andcervical third in G1. Statistical difference (Kruskal-Wallis -Anova) was observed (p<0.05) between G1 and G3 in theapical third and G1 and G2 in the middle third. No differencewas observed in the cervical third (p>0.05). Conclusion:Different speeds are necessary for the correct fillingof the root canal with calcium hydroxide paste. The 15,000rpm speed was more effective in filling the apical third and5,000 rpm speed was more effective in filling the cervicaland middle thirds.

Capacidade de selamento marginal apical propiciado por alguns materiais retrobturadores / Apical sealing ability of some retrograde filling materials

OBJETIVO: Analisar a microinfiltração marginal através da penetração linear de corante Rodamina B em obturações retrógradas utilizando diferentes materiais. MÉTODOS: Sessenta e um dentes permanentes extraídos e tratados endodonticamente tiveram seus 3 mm apicais amputados transversalmente e retrocavidades com 3 mm de profundidade foram preparadas com pontas de ultrasson. Os espécimes foram divididos em grupos experimentais onde os materiais retrobturadores foram inseridos e submersos em corante por 24 horas. Os grupos continham Super EBA, MTA, Histoacryl além dos controles positivo e negativo. RESULTADOS: A microinfiltração marginal analisada com auxílio de computador, utilizando o programa Image J e aplicando-se o teste de comparação múltipla de Kruskal Wallis, mostraram diferença entre os materiais testados. Em ordem decrescente de capacidade de selamento marginal aparece o Histoacryl com o melhor desempenho, não apresentando nenhum espécime com microinfiltração, seguidos do Super EBA e MTA com comportamentos estatisticamente semelhantes. CONCLUSÃO: O grupo do histoacryl foi o que apresentou o melhor vedamento entre os três materiais comparados.

OBJECTIVE: Assess marginal leakage by linear penetration of rhodamine B dye in retrograde fillings filled with different materials. METHODS: Sixty-one permanent teeth extracted and treated endodontically had their 3 apical millimeters amputated cross-sectionally and 3 mm deep retro-cavities were prepared with ultrasonic tips. The specimens were divided into experimental groups where the retrofilled materials were inserted and submerged in a dye for 24 hours. The groups consisted of Super EBA, MTA and Histoacryl, in addition to the positive and negative controls. RESULTS: Marginal leakage was analyzed by the Image J software and multiple comparisons with the Kruskal-Wallis test revealed differences among the materials. The material with the best marginal sealing capacity was Histoacryl. None of the specimens sealed with this product presented leakage. Super EBA was next in terms of sealing capacity followed by MTA, but their performances were similar. CONCLUSION: Histoacryl presented the best sealing capacity of the three studied materials.

In vitro analysis of thermocompaction time and gutta-percha type on quality of main canal and lateral canals filling.

The aim of this study was to evaluate the quality of filling in main and lateral root canals performed with the McSpadden technique, regarding the time spent on the procedure and the type of gutta-percha employed. Fifty simulated root canals, made with six lateral canals placed two apiece in the cervical, middle and apical thirds of the root, were divided into 5 groups. Group A: McSpadden technique with conventional gutta-percha, performed with sufficient time for canal filling; Group B: McSpadden technique with conventional gutta-percha, performed in twice the mean time used in Group A; Group C: McSpadden technique with TP gutta-percha, performed with sufficient time for canal filling; Group D: McSpadden technique with TP gutta-percha, performed in twice the mean time used in Group C; Group E: lateral condensation technique. Images of the filled root canals were taken using a stereomicroscope and analyzed using the Leica QWIN Pro software for filling material flow, gutta-percha filling extension and sealer flow. Data were analyzed by analysis of variance (ANOVA) and Tukey test (p < 0.05). The best values of penetration in lateral canals in the middle third occurred in the groups where TP gutta-percha was used. However, in the apical third, group B showed the best values. Although a longer time of compactor use allows greater penetration of the filling material into the lateral canals, the presence of voids resulted in bad quality radiographic images, suggesting porosity. The best quality of filling material was observed in Group A (McSpadden technique with conventional Gutta-Percha, performed with sufficient time for root canal filling).

In vitro analysis of thermocompaction time and gutta-percha type on quality of main canal and lateral canals filling

The aim of this study was to evaluate the quality of filling in main and lateral root canals performed with the McSpadden technique, regarding the time spent on the procedure and the type of gutta-percha employed. Fifty simulated root canals, made with six lateral canals placed two apiece in the cervical, middle and apical thirds of the root, were divided into 5 groups. Group A: McSpadden technique with conventional gutta-percha, performed with sufficient time for canal filling; Group B: McSpadden technique with conventional gutta-percha, performed in twice the mean time used in Group A; Group C: McSpadden technique with TP gutta-percha, performed with sufficient time for canal filling; Group D: McSpadden technique with TP gutta-percha, performed in twice the mean time used in Group C; Group E: lateral condensation technique. Images of the filled root canals were taken using a stereomicroscope and analyzed using the Leica QWIN Pro software for filling material flow, gutta-percha filling extension and sealer flow. Data were analyzed by analysis of variance (ANOVA) and Tukey test (p < 0.05). The best values of penetration in lateral canals in the middle third occurred in the groups where TP gutta-percha was used. However, in the apical third, group B showed the best values. Although a longer time of compactor use allows greater penetration of the filling material into the lateral canals, the presence of voids resulted in bad quality radiographic images, suggesting porosity. The best quality of filling material was observed in Group A (McSpadden technique with conventional Gutta-Percha, performed with sufficient time for root canal filling).

Effect of pretreatment dexamethasone on postendodontic pain.

OBJECTIVE: This study evaluates the use of a preoperative single oral dose of dexamethasone for the prevention and control of postendodontic pain. STUDY DESIGN: Forty-seven patients were randomly assigned to 2 groups: placebo and dexamethasone (4 mg). The medications were administered 1 hour before the start of endodontic treatment. Postoperative pain was assessed after 4, 12, 24, and 48 hours. RESULTS: Dexamethasone resulted in a statistically significant reduction in postendodontic pain at 4 and 12 hours (P < .05). However, no statistical difference (P > .05) was observed at 24 and 48 hours (Mann-Whitney test). The placebo group exhibited higher rescue medication intake (P < .05; Student t test). No side effects were reported for any of the medications used. CONCLUSION: Preoperative single oral dose of dexamethasone substantially reduced postendodontic pain. Further studies are needed to evaluate the applicability of these findings to other clinical conditions and drug regimens.

Sistema BioRace: segurança e eficiência / The BioRace system: safe and efficiency

A eficácia do processo de sanificação do sistema de canais radiculares está em função direta de suaampliação. Quanto maior a ampliação melhor é a qualidade de limpeza e sanificação uma vez que a substânciaquímica atua com mais efetividade e, quando da necessidade de uma medicação intracanal, esta atuacom toda a sua potencialidade. Os sistemas rotatórios de NiTi tem se revelado uma inovação importante,mas os kits desenvolvidos pelos fabricantes tem se limitado a uma ampliação reduzida da crítica zona apical.O sistema BioRace da FKG Dentaire, Switzerland, foi desenvolvido atendendo os princípios de segurança,efetividade e contemplando os princípios biológicos que permitem maior ampliação do terço apical, áreacrítica para o controle da infecção endodôntica. No presente artigo os autores apresentam, analisam e apresentamo protocolo clínico para a sua utilização.

The efficacy of the sanitization process in root canal preparation is dependent on its enlargement.With greater enlargement of the root canal, the irrigating solution activity is higher and intracanal dressingacts on its total potential. The development of NiTi rotary systems is a revolution in endodontic therapy, butthe kits available in the market are limited in enlarging the apical third. The BioRace system by FKG Dentairewas developed attending to efficient, safe and biological based sequence files. The authors present the systemand establish a protocol for its clinical application.

A model system to study antimicrobial strategies in endodontic biofilms

The purpose of this work was to develop a model system to study antimicrobial strategies in endodontic biofilms. Enterococcus faecalis suspension was colonized in 10 human root canals. Five milliliters of Brain Heart Infusion (BHI) were mixed with 5 mL of the bacterial inoculums (E. faecalis) and inoculated with sufficient volume to fill the root canal during 60 days. This procedure was repeated every 72 h, always using 24-h pure culture prepared and adjusted to No. 1 MacFarland turbidity standard. Biofilm formation was analyzed by scanning electron microscopy (SEM). E. faecalis consistently adhered to collagen structure, colonized dentin surface, progressed towards the dentinal tubules and formed a biofilm. The proposed biofilm model seems to be viable for studies on antimicrobial strategies, and allows for a satisfactory colonization time of selected bacterial species with virulence and adherence properties.

A model system to study antimicrobial strategies in endodontic biofilms.

The purpose of this work was to develop a model system to study antimicrobial strategies in endodontic biofilms. Enterococcus faecalis suspension was colonized in 10 human root canals. Five milliliters of Brain Heart Infusion (BHI) were mixed with 5 mL of the bacterial inoculums (E. faecalis) and inoculated with sufficient volume to fill the root canal during 60 days. This procedure was repeated every 72 h, always using 24-h pure culture prepared and adjusted to No. 1 MacFarland turbidity standard. Biofilm formation was analyzed by scanning electron microscopy (SEM). E. faecalis consistently adhered to collagen structure, colonized dentin surface, progressed towards the dentinal tubules and formed a biofilm. The proposed biofilm model seems to be viable for studies on antimicrobial strategies, and allows for a satisfactory colonization time of selected bacterial species with virulence and adherence properties.

Antibacterial efficacy of intracanal medicaments on bacterial biofilm: a critical review

The purpose of this paper is to discuss critically the antibacterial efficacy of intracanal medicaments on bacterial biofilm. Longitudinal studies were evaluated by a systematic review of English-language articles retrieved from electronic biomedical journal databases (MEDLINE, EMBASE, CENTRAL) and handsearching records, using different matches of keywords for root canal biofilm, between 1966 and August 1st, 2007. The selected articles were identified from titles, abstracts and full-text articles by two independent reviewers, considering the tabulated inclusion and exclusion criteria. Disagreements were resolved by consensus. The search retrieved 91 related articles, of which 8.8 percent referred to in vivo studies demonstrating the lack of efficacy of endodontic therapy on bacterial biofilm. Intracanal medicaments were found to have a limited action against bacterial biofilm.