Intentional replantation for the retreatment of mandibular second molar: a case report / 华西口腔医学杂志

When the use of root canal retreatment and apical surgery experiences difficulty in treating endodontic diseases, intentional replantation is an optional clinical technique used to retain the tooth. A 28-year-old female complained of chewing discomfort at the mandibular second molar after undergoing root canal treatment 3 month ago. History record and radiographic examination revealed that a C-shaped root canal system was filled with gutta-percha in the mandibular second molar. A radiolucency area existed at the root furcal area with a thin canal wall in the distal and mesial roots. Intentional replantation was used to treat this tooth. The clinical and radiographic results showed that intentional replantation and nano-biomaterial application facilitated infection control, tooth retention, and periodontal tissue regeneration.

Influência do cimento na radiopacidade de obturações com cone único / Sealer influence on radiopacity of single cone root canal fillings

Objetivo: o objetivo deste estudo foi avaliar a influência dos cimentos AH Plus e Endofill na radiopacidade de obturações em canais simulados, usando-se a técnica do cone único. Métodos: vinte blocos de resina com canais curvos simulados foram preparados até o instrumento rotatório ProTaper Universal F3. Após a irrigação final, os canais foram secos com cones de papel, e um cone de guta-percha F3 foi inserido no canal; em seguida, uma radiografia digital foi realizada para cada espécime. Os espécimes foram distribuídos aleatoriamente em dois grupos experimentais (n = 10), de acordo com cimento empregado. AH Plus e Endofill foram os cimentos associados à guta-percha para obturação dos canais. Após a presa final dos cimentos, novas imagens digitais foram realizadas, da mesma forma que as radiografias pré-operatórias. As imagens das radiografias antes e após a associação da guta-percha com o cimento foram sobrepostas e analisadas, para se registrar o número de pixels das imagens. A análise estatística foi realizada utilizando-se os testes t de Student e Wilcoxon, com nível de significância de 5%. Resultados: ambos os grupos apresentaram radiopacidade semelhante para a guta-percha (p > 0,05). No entanto, a adição do cimento aumentou significativamente (p < 0,05) a radiopacidade das imagens radiográficas. A radiopacidade foi aumentada em 68,10% com o cimento AH Plus e em 46,02% com o cimento Endofill, com diferença estatisticamente significativa entre os cimentos. Conclusões: os cimentos aumentaram significativamente a radiopacidade da obturação com a técnica do cone único. O cimento AH Plus foi mais radiopaco do que o cimento Endofill.

Materials used for indirect pulp treatment in primary teeth: a mixed treatment comparisons meta-analysis

Abstract: This study aimed to systematically review the literature to address the question regarding the influence of different materials in the clinical and radiographic success of indirect pulp treatment in primary teeth. A literature search was carried out for articles published prior to January 2017 in PubMed/MEDLINE, CENTRAL, Scopus, TRIP and ClinicalTrials databases; relevant articles included randomized clinical trials that compared materials used for indirect pulp treatment in primary teeth. Two reviewers independently selected the studies and extracted the data. The effects of each material on the outcome (clinical and radiographic failures) were analyzed using a mixed treatment comparisons meta-analysis. The ranking of treatments according to their probability of being the best choice was also calculated. From 1,088 potentially eligible studies, 11 were selected for full-text analysis, and 4 were included in the meta-analysis. In all papers, calcium hydroxide liner was used as the control group versus an adhesive system, resin-modified glass ionomer cement or placebo. The follow-up period ranged from 24 to 48 months, with dropout rates of 0-25.7%. The material type did not significantly affect the risk of failure of the indirect pulp treatment. However, calcium hydroxide presented a higher probability of failure. In conclusion, there is no scientific evidence showing the superiority of any material used for indirect pulp treatment in primary teeth.

Efeito de diferentes sistemas de obturação na resistência à fratura de raízes tratadas endodonticamente / The Influence of different obturation systems on the fracture resistance of endodontically treated roots

Objective: This study aimed to compare the fracture resistance of endodontically treated roots filled by different obturation systems. Material and methods: Ninety-six maxillary central incisors were used and decoronated, retaining 12 mm of the roots. On the basis of obturation systems, the roots were randomly divided into 4 groups (n=24): Group1 (COGR): control group (unprepared, unfilled), Group 2 (AVGR): ActiV GP points/ActiV GP sealer, Group 3 (GPGR): Gutta percha points / AH plus sealer, and Group4 (GAGR): Gutta percha points/ActiV GP sealer. The last three groups were obturated with the single cone technique. The roots were then stored in 100% relative humidity at 37 °C for 2 weeks. A vertical compressive force was exerted in a universal testing machine until fracture occurred. Data were statistically analyzed using one-way ANOVA. Results: Mean (SD) failure loads for groups ranged from 920.51 ± 210.37 to 1113.44 ± 489.42 N. The fracture resistance between the different study groups indicated no statistical difference (p>0.05). Conclusions: ActiV GP system did not exert a significant effect on the fracture resistance of endodontically treated teeth.(AU)

Objective: Comparar a resistência à fratura de raízes tratadas endodonticamente obturadas através de diferentes sistemas. Materiais e Métodos: Noventa e seis incisivos centrais superiores foram utilizados, tiveram as coroas removidas, restando 12 mm de raíz. De acordo com o sistema de obturação, as raízes foram divididas em 4 grupos (n=24): Grupo1 (COGR): grupo controle (sem preparo, sem preenchimento), Grupo2 (AVGR): cones ActiV GP / cimento ActiV GP, Grupo3 (GPGR): cones de guta percha / cimento AH plus, e Grupo4 (GAGR): cones de guta percha / cimento ActiV GP. Os últimos três grupos foram obturados através da técnica de cone único. As raízes foram armazenadas em 100% de umidade relativa a 37 °C durante 2 semanas. Uma força compressiva vertical foi aplicada através de uma máquina de ensaio universal até ocorrer fratura. Os dados foram analisados estatisticamente através de ANOVA ­ 1 fator. Resultados: A carga média (SD) obtida no momento da falha variou entre 920.51 ± 210.37 até 1113.44 ± 489.42 N. A resistência à fratura entre os diferentes grupos estudados não indicaram diferença estatística. Conclusão: O sistema ActiV GP não exerceu um efeito significante na resistência à fratura em dentes tratados endodonticamente.(AU)

Effect of root canal filling techniques on the bond strength of epoxy resin-based sealers

Abstract The aim of this study was to evaluate the effects of different root canal filling techniques on the bond strength of epoxy resin-based sealers. Sixty single-rooted canines were prepared using ProTaper (F5) and divided into the following groups based on the root filling technique: Lateral Compaction (LC), Single Cone (SC), and Tagger Hybrid Technique (THT). The following subgroups (n = 10) were also created based on sealer material used: AH Plus and Sealer 26. Two-millimeter-thick slices were cut from all the root thirds and subjected to push-out test. Data (MPa) was analyzed using ANOVA and Tukey's test (α = 0.05). The push-out values were significantly affected by the sealer, filling technique, and root third (p < 0.05). AH Plus (1.37 ± 1.04) exhibited higher values than Sealer 26 (0.92 ± 0.51), while LC (1.80 ± 0.98) showed greater bond strength than THT (1.16 ± 0.50) and SC (0.92 ± 0.25). The cervical (1.45 ± 1.14) third exhibited higher bond strength, followed by the middle (1.20 ± 0.72) and apical (0.78 ± 0.33) thirds. AH Plus/LC (2.26 ± 1.15) exhibited the highest bond strength values, followed by AH Plus/THT (1.32 ± 0.61), Sealer 26/LC (1.34 ± 0.42), and Sealer 26/THT (1.00 ± 0.27). The lowest values were obtained with AH Plus/SC and Sealer 26/SC. Thus, it can be concluded that the filling technique affects the bond strength of sealers. LC was associated with higher bond strength between the material and intra-radicular dentine than THT and SC techniques.

Eficácia das limas manuais e do sistema MTwo R na redução bacteriana em dentes tratados endodonticamente com lesão periapical crônica / Effectiveness of hand files and the MTwo R system in bacterial reduction in endodontically treated teeth with chronic apical periodontitis

Objetivo: o objetivo desse estudo foi comparar, in vivo,a eficácia de duas técnicas para remoção da guta-percha(limas manuais e o sistema MTwo R) na redução microbianaapós o preparo químico-mecânico em dentes tratadosendodonticamente e com lesão periapical crônica.Material: trinta dentes unirradiculares obturados, comlesão periapical crônica, foram divididos em dois grupos.Um grupo teve a remoção da guta-percha por meiode limas manuais (n = 15), enquanto o outro grupo utilizouas limas rotatórias MTwo R (n = 15). Após a remoçãoda guta-percha, a primeira amostra (S1) foi obtida.Em seguida, foi realizado o preparo químico-mecânico euma segunda coleta (S2). A carga bacteriana foi determinadapor meio da técnica de cultura. Aplicou-se ostestes estatísticos de Wilcoxon e de Mann-Whitney. Resultados:em S1, todos os canais mostraram a presençabacteriana nos grupos manual e MTwo R, com medianade 5,14 x 103 (variação 20-1,7 x 105) e 3,4 x 102 (variação20-3,14 x 103), respectivamente. Em S2, a redução bacterianafoi detectada nos dois grupos (p < 0,05). Conclusão:conclui-se que o MTwo R mostrou significativaredução bacteriana durante o retratamento endodôntico.

Acurácia do diâmetro de ponta de cones de gutapercha com diferentes conicidades / Accuracy of the tip diameter on gutta-percha cones of different tapers

Objetivo: O objetivo deste estudo foi analisar o diâmetro da ponta de cones de guta-percha com diferentes conicidades, considerando a especificação do fabricante. Materiais e Métodos: Cento e quarenta cones de guta percha (Dentsply Maillefer): F2, F3, e 25, 30, 35 e 40 de conicidade .02, .04 e .06 (n = 10) foram utilizados neste estudo. Os cones foram presos em uma régua calibradora, e observados em microscópio ótico com aumento de 40x. Então, o diâmetro da ponta de cada cone foi medido com paquímetro digital. Os dados foram categorizados como corretos ou incorretos utilizando margem de erro de ±0,01 mm e submetidos ao teste Exato de Fisher (p ≤ 0,05). Resultados: Somente 4 cones de guta percha estavam incorretos, porém não houve diferença estatisticamente significativa entre os cones em relação ao padrão estabelecido pelo fabricante.Conclusão: Conclui-se que os cones principais da marca Dentsply Maillefer, independente de sua conicidade(.02, .04, .06, F2 e F3), possuem o diâmetro da ponta calibrado de acordo com a especificação do fabricante.

Efeito da adição de partículas de vidro niobofosfato bioativo à guta-percha: desenvolvimento, caracterização, resistência de união à dentina e influência na formação de biofilmes microbianos / Effect of the addition of the niobophosphate bioactive glass in the gutta-percha: Development, characterization, bond strength to dentin and influence on biofilm formation

Os objetivos deste estudo foram desenvolver e caracterizar um compósito para obturação endodôntica à base de guta-percha e vidro niobofosfato. Foi avaliado a resistência de união à dentina radicular do compósito experimental, da guta EndoSequence BC, ambos sem o uso de cimento além do cimento AH Plus associado a guta-percha através do ensaio de push-out. A análise dos padrões de fratura foi realizada com auxílio de MEV. Análises usando EDX and MEV-EDS foram realizadas para verificar a composição e distribuição das partículas de vidro na superfície e no interior da matriz de guta-percha dos materiais testados. Os resultados foram analisados estatisticamente pelos testes ANOVA e Tukey, sendo considerado significante quando p < 0,05. Foi avaliado também a influência do compósito experimental, do vidro niobofosfatos bioativo, diferentes tipos de gutapercha e hidroxiapatita na adesão e formação de biofilme por bactérias orais com coloração Live/dead usando um microscópio confocal à laser. O biofilme multiespécies foi formado na superfície de discos de hidroxiapatita - HA, vidro niobofosfato - VNB, guta-percha Obtura - OBT, guta-percha Protaper - PTP, EndoSequence BC guta-percha - GBC e o compósito experimental guta-percha associado com o vidro niobofosfato - GNB. O biovolume total (mm3), biovolume de bacterias viáveis (mm3), e porcentagem de bactérias viáveis (%) foram quantificados...

The objectives of this study were to develop and characterize a composite for endodontic obturation based gutta-percha and niobium phosphate glass. The study evaluated the composites micropush-out bond strength to root dentine of the experimental gutta-percha and niobium phosphate glass composite applied with thermoplastic technique to the root canals without sealer in a moist environment and compare to the conventional root canal obturation Ah Plus and gutta-percha, and a commercial bioceramic gutta without sealer. Additionally, the cores materials were characterized using Scanning Electron Microscopic/Energy-dispersive X-ray (SEM/EDS) and Energy Dispersive X-ray fluorescence spectrometry (EDX) analysis. The failure mode was analyzed with SEM. Analysis using EDX and SEMEDS was carried out to verify the composition and distribution of the particles of the tested materials. Data were statistically analyzed by one-way ANOVA and Tukeys test (p < 0,05). Also was analysed the influence of different types of gutta-percha and bioactive niobium phosphate glass on the adherence and biofilm formation by oral bacteria from human dental plaque with Live/dead staining assay using confocal laser scanning microscopy (CLSM). The multispecies biofilm was grown from plaque bacteria on discs of hydroxyapatite - HA, niobium phosphate bioactive glass- VNB, Obtura pellets - OBT, Protaper gutta-percha - PTP, EndoSequence BC gutta-percha - GBC and gutta-percha associated with niobium phosphate glass - GNB in brain-heart infusion broth for 3,14 and 30 days. After the growth induction periods, specimens were stained by using Live/Dead, and the images were analyzed under a CLSM...

Sealing Ability of MTA Used as a Root End Filling Material: Effect of the Sonic and Ultrasonic Condensation

Despite the excellent properties of mineral trioxide aggregate (MTA), the condensation technique may have some influence in its sealing ability. The purpose of this study was to compare the sealing ability of sonic and ultrasonic setting of MTA. Thirty-four extracted human teeth had their canals prepared and filled with Sealapex sealer and gutta-percha using the active lateral condensation technique. The teeth were rendered waterproof and apicoectomy performed at 3 mm from the apex. Root-end cavities (3.0 mm deep and 1.4 mm diameter) were prepared with diamond ultrasonic tips. The root-end cavities were filled with Pro-Root MTA® with ultrasonic vibration, sonic vibration or no vibration. The positive control group did not receive any material while the negative control group was totally rendered waterproof. After material set, the specimens were immersed in Rodhamine B for 24 h, under vacuum in the first 15 min, then washed, dried and split longitudinally for evaluating the infiltration at the dentin/material interface. Data were analyzed using ANOVA and Tukey's tests at 5% significance level. Sonic vibration promoted the lowest infiltration values (p<0.05). It was concluded that sonic vibration could be considered an efficient aid to improve the sealing ability of MTA when used as root-end filling material.

Resumo O objetivo deste estudo foi avaliar in vitro, a influência da vibração sônica e ultrassônica no selamento marginal proporcionado pelo MTA. Trinta e quatro dentes humanos tiveram seus canais radiculares instrumentados e obturados com cimento Sealapex® pela técnica da condensação lateral ativa. Os dentes foram impermeabilizados e seccionados os 3 mm apicais. Retrocavidades (3 mm de profundidade e 1,4 mm de diâmetro) foram preparadas com pontas ultrassônicas diamantadas. As retrocavidades foram preenchidas com Pro-Root MTA® com auxílio da vibração ultrassônica, com auxílio da vibração sônica e sem vibração alguma. O grupo controle positivo não recebeu material retrobturador, enquanto que o negativo foi totalmente impermeabilizado. Após a presa do material, os espécimes foram mergulhados em Rodamina B por 15 min em vácuo, permanecendo nesta solução por mais 24 h. Em seguida, foram lavados, secados e clivados longitudinalmente para avaliação da infiltração do corante na interface dentina/material retrobturador. Os dados foram analisados utilizando a análise de variância e o teste de Tukey (p<0,05). Observou-se que apenas a vibração sônica foi diferente apresentando os menores índices de infiltração. Pode-se concluir que vibração sônica contribui com a melhora da capacidade de selamento marginal proporcionado pelo MTA quando empregado como material retrobturador. .

Apical Barrier Formation After Incomplete Orthograde MTA Apical Plug Placement in Teeth with Open Apex - Report of Two Cases

Two cases are reported in which incomplete placement of 4 mm mineral trioxide aggregate (MTA) plug was performed unintentionally at the apical third of permanent immature teeth with open apex and apical periodontitis. As confirmed radiographically, there were gaps between MTA and dentinal walls along the MTA-dentin interface. After setting of MTA was confirmed, endodontic treatment was completed and access was sealed with composite resin. At 6 to 16 months follow-up examinations, formation of dentin in contact with the MTA surface, as well as apical closure and periapical healing were ideied radiographically for both cases. The results of these cases showed that apical barrier formation and complete periapical healing is possible despite the incomplete apical placement of the MTA plug. This might be due to the biological properties of the MTA. Even so, an incomplete three-dimensional placement of the filling material is not advocated.

An in vitro comparison between the apical sealing abilities of resilon with Epiphany® sealer and gutta-percha with AH plus sealer.

Context: The study assesses the apical sealing ability of two obturating materials (resilon and gutta-percha) with their sealants by means of the dye penetration method using India ink. Aims: To compare the resistance to apical dye penetration between resilon (with Epiphany sealer; Epiphany®, Pentron clinical technologies, USA) and gutta-percha (with AH Plus sealer; Dentsply, Maillefer, Germany). It was hypothesized that there would be no difference between the two groups with regard to apical dye penetration. Settings and design: Hundred mandibular first premolars from individuals aged between 20 to 25 years were selected after their lengths were standardized. Materials and Methods: Instrumentation was performed with NiTi hand protaper files (Dentsply, Maillefer) using EDTA paste and copious irrigation with 2.5% sodium hypochlorite. Experimental group 1 consisted of roots that were treated with Epiphany primer and obturated with resilon (with Epiphany sealer). Experimental group 2 consisted of those obturated with gutta-percha using AH Plus sealer. The samples were immersed in blue India Ink and cleared using 5% nitric acid. Dye penetration was assessed under a stereomicroscope. Statistical analysis: Mann-Whitney U test. Results: Roots obturated with resilon core material and Epiphany sealer exhibited lesser mean apical dye penetration (1.281 mm; SD: 0.742) in comparison to those obturated with gutta-percha and AH plus sealer (2.154 mm; SD: 0.814). The difference was found to be highly significant (P<0.0025). Conclusion: Resilon (with Epiphany sealer) provided better radicular apical sealing in comparison to gutta percha (with AH Plus sealer).

A SEM evaluation of dentinal adaptation of root canal obturation with GuttaFlow and conventional obturating material.

Objective: The aim of this in-vitro study was to compare dentinal adaptation of conventional obturating material and GuttaFlow in young permanent teeth of child patients. Materials and Methods: Ten young permanent anterior teeth with closed foramen were selected for the study. Root canal preparations were carried out using a step back technique. The canal was alternately irrigated with 5.25% sodium hypochlorite solution and 17% EDTA and normal saline. After root canal preparation specimens were randomly divided into two groups (n=5). GROUP "A": Obturated with zinc-oxide eugenol sealer and gutta-percha cone using cold lateral obturation technique. GROUP "B": Obturated with GuttaFlow as per the manufacturer's instruction. The teeth were split into two halves. Five randomly chosen longitudinal split teeth samples each from Group "A" and Group "B" was observed under scanning electron microscope to access the interface between obturating material and dentin at the level of 2 mm from the apex. Results: On statistical analysis the dentinal adaptation (μm) of Group A was observed with a mean of 0.52 and standard deviation 0.15, while the value of mean and standard deviation were noted 0.12 and 0.02 for Group B. The "t" value on comparison of Group A and Group B is 5.79 with "P " value of <0.001, which is highly significant. Conclusion: From result of the study it can be concluded Group B samples showed significantly superior seal when compared with Group A. Complete seal was not observed in any of Group A samples.

Microscope-aided endodontic treatment of maxillary first premolars with three roots: A case series.

Maxillary premolars have a highly variable root canal morphology. However, the presence of three roots is a rare occurrence. This clinical article describes the unusual anatomy detected in maxillary premolars during routine endodontic treatment using microscope. The diagnosis and clinical management of maxillary first premolars with three roots and canals using radiographic interpretation, access cavity modification and visual enhancement with operative microscopes is discussed in the article.

Effectiveness of gutta-percha and Resilon in filling lateral root canals using the Obtura II system

The aim of this study was to evaluate the effectiveness of gutta-percha and Resilon in filling lateral root canals by using the Obtura II system. Root canals of artificial teeth were prepared using a standard protocol, and lateral canals were made in three thirds of the root canal. The root canals were filled with either Obtura gutta-percha (OB), Endo-points flow gutta-percha (ED), or Resilon (RE) by using the Obtura II system. The fillings were evaluated using digitized radiographs and analyzed by using Image Tool software. Outlines of the total areas of the lateral canals and the filled areas were used to determine the percentage of filling in each lateral canal. Data were analyzed with the Kruskal-Wallis and Dunn tests at a 5 percent significance level. RE and ED showed better results than OB did in the three thirds of the root canals. When the root canal thirds were compared, OB and RE were more effective in the cervical third than in the apical third (p < 0.05). In conclusion, Resilon and EndoFlow gutta-percha were effective in filling lateral canals by using the Obtura II system.

Effect of cavity varnish and intermediate restorative material on coronal microleakage in endodontically treated tooth.

Aim: Evaluation of microleakage in endodontically treated teeth that have been coronally sealed with eugenol and noneugenol containing zinc oxide cement, with and without the use of cavity varnish. Materials and Methods: The crowns of single rooted teeth were removed at the cementoenamel junction (CEJ) and the root canals were prepared and obturated with gutta-percha points and zinc oxide eugenol (ZOE) sealer using lateral condensation technique. The samples were randomly divided into four groups-group 1, coronal seal was obtained with ZOE cement; in group 2, three coats of cavity varnish followed with coronal seal of ZOE cement; in group 3, Litark a (noneugenol cement) was placed in the prepared cavity as in group 1; and in group 4, cavity varnish and Litark were placed instead of ZOE as in group 2. The specimens were immersed in 2% methylene blue dye and examined under traveling microscope for evidence of dye penetration of the material. Statistical Analysis: In this study, Kruskal-Wallis test, Mann-Whitney U, and Wilcoxon W tests were used. Results: Kruskal-Wallis test with P=0.000 indicated that a significant difference exists between the four groups. Mann-Whitney U test and Wilcoxon W test showed a significant difference at 0.05 levels as follows: group 1 with group 3 and 4, group 2 with group 3 and 4, and group 3 with group 4. There was no significant difference at 0.05 levels between group 1 and group 2. Conclusion: Group 4 showed significant less amount of dye penetration as compared with other groups.

Avaliação da extrusão de material obturador durante a técnica termomecânica usando diferentes tampões apicais / Extrusion evaluation of root filling material during thermomechanical condensation of gutta-percha using different apical plugs

Objetivo: Analisar a extrusão de material obturador durante a técnica termomecânica, valendo-seda utilização de tampão apical com hidróxido de cálcio associado ao iodofórmio e com o AgregadoTrióxido Mineral (MTA). Materiais e Métodos: Foram utilizados 30 caninos permanentes, os quais foramdivididos em três grupos: G1 - tampão apical com MTA; G2 - tampão com hidróxido de cálcio associadoao iodofórmio; G3 (controle) - sem tampão apical. Após a obturação dos dentes foi verificada a extrusão dematerial obturador, por análise direta do ápice através de lupa. Os dados obtidos foram submetidos ao teste Qui-quadrado com nível de significância de 5%. Resultados: O grupo do tampão apical com hidróxido de cálcio associado ao iodofórmio foi similar ao grupo sem tampão apical, e ambos foram estatisticamente diferentes do grupo do MTA (p=0,024). Conclusão: O tampão apical realizado com MTA foi mais eficaz no controle da extrusão de material obturador durante a obturação pela técnica termomecânica.

Estudo comparativo de quatro técnicasde obturação dos canais radiculares: (revisão de literatura)

Todas as etapas que constituem um tratamento endodôntico são de fundamental importância para se obter o sucesso terapêutico. A partir de um efetivo selamento apical, é possível impedir a entrada de fuidos teciduais oriundos do periápice...

Nd:YAG laser irradiation effect on apical intracanal dentin - a microleakage and SEM evaluation

The purpose of this in vitro study was to evaluate the effect of neodymium:yttrium-aluminum-garnet (Nd:YAG) laser irradiation on intracanal dentin surface by SEM analysis and its interference in the apical seal of filled canals. After endodontic treatment procedures, 34 maxillary human incisors were randomly assigned to 2 groups. In the negative control group (n=17), no additional treatment was performed and teeth were filled with vertically condensed gutta-percha; in the laser-treated group (n=17), the root canals were irradiated with Nd:YAG laser (1.5 W, 100 mJ, 15 Hz) before filling as described for the control group. Two specimens of each group were prepared for SEM analysis to evaluate the presence and extent of morphological changes and removal of debris; the other specimens were immersed in 0.5 percent methylene blue dye (pH 7.2) for 24 h for evaluation of the linear dye leakage at the apical third. SEM analysis of the laser-treated group showed dentin fusion and resolidification without smear layer or debris. The Student’s t-test showed that the laser-treated group had significantly less leakage in apical third than the control group. Within the limitations of this study, it may be concluded that the morphological changes on the apical intraradicular dentin surface caused by Nd:YAG laser resulted in less linear dye apical leakage.

Apical microleakage and SEM analysis of dentin surface after 980 nm diode laser irradiation

This study evaluated the effect of 980-nm diode laser on apical microleakage and intraradicular dentin morphology. Roots of 110 mandibular incisors were used in the study: 92 for microleakage test and 18 for scanning electron microscopy (SEM). Roots were randomly assigned to 3 groups according to the irrigating solution (water, NaOCl and NaOCl/EDTA) and were divided into 3 subgroups according to the laser irradiation protocol (without irradiation, irradiated at 1.5 W and irradiated at 3.0 W). Two specimens of each subgroup were prepared for SEM. The remaining roots were filled with AH Plus and gutta-percha. Apical leakage was assessed by ink penetration and data were analyzed statistically by ANOVA and Tukey-Krammer test (α=0.05). SEM analysis showed intensification of changes with increase of laser power as well as variations according to the irrigating solution. Modified smear layer was observed in specimens treated with water and irradiated with laser. Roots irrigated with NaOCl/EDTA had lower levels of infiltration (0.17 ± 0.18 mm) differing significantly (p<0.05) from those of roots irrigated with water (0.34 ± 0.30 mm), but similar (p>0.05) to those irrigated with NaOCl (0.28 ± 0.29 mm). Non-irradiated roots had lower levels of infiltration (0.10 ± 0.14 mm), differing (p<0.05) from those irradiated at 1.5 W (0.32 ± 0.22 mm) and 3.0 W (0.37 ± 0.32 mm). The 980 nm diode laser modified dentin morphology and increased apical microleakage.

Este estudo avaliou o efeito do laser de diodo 980 nm na microinfiltração apical e na morfologia intrarradicular da dentina. Raízes de 110 incisivos inferiores foram utilizadas no estudo: 92 para o teste de microinfiltração e 18 para microscopia eletrônica de varredura (MEV). As raízes foram divididas em 3 grupos de acordo com a solução irrigante (água, NaOCl e NaOCl/EDTA) e subdivididas em 3 de acordo com a irradiação laser (sem irradiação, irradiados com 1,5 W e irradiados com 3,0 W). Duas amostras de cada subgrupo foram preparadas para MEV. As raízes restantes foram preenchidas com AH Plus e guta percha. A infiltração apical foi avaliada nas raízes por meio da penetração do corante e os dados foram analisados por ANOVA e teste de Tukey-Krammer (α=0,05). Os resultados da MEV mostraram intensificação das mudanças quando se aumentou a potência do laser e variações de acordo com a solução irrigadora. Camada de smear modificada foi observada em espécimes tratados com água e irradiados com laser. Raízes irrigadas com NaOCl/EDTA tiveram níveis menores de infiltração (0,17 ± 0,18 mm) estatisticamente diferente (p<0,05) das raízes irrigadas com água (0,34 ± 0,30 mm), mas semelhante (p>0,05) aos irrigados com NaOCl (0,28 ± 0,29 mm). As raízes não irradiadas tiveram níveis menores de infiltração (0,10 ± 0,14 mm), diferente (p<0,05) de 1,5 W (0,32 ± 0,22 mm) e 3.0 W (0,37 ± 0,32 mm). O laser de diodo 980 nm alterou a morfologia da dentina e aumentou a infiltração marginal apical.

Influence of ferrule preparation with or without glass fiber post on fracture resistance of endodontically treated teeth

OBJECTIVE: This study evaluated the effect of ferrule preparation (Fp) on the fracture resistance of endodontically treated teeth, restored with composite resin cores with or without glass fiber posts. MATERIAL AND METHODS: Forty-four bovine teeth were sectioned 19 or 17 mm (2 mm ferrule) from the apex, endodontically treated and assigned to four groups (n = 11): Group 1: Fp and post; Group 2: Fp and without post; Group 3: without Fp and with post; Group 4: without Fp and without post. All specimens were restored with composite resin core and metal crown. Specimens were subjected to fracture resistance testing in a universal testing machine at a crosshead speed of 0.5 mm/min. The data were analyzed by two-way ANOVA and Tukey's tests (α=0.05). RESULTS: The mean fracture resistance values were as follows: Group 1: 573.3 N; Group 2: 552.5 N; Group 3: 275.3 N; Group 4: 258.6 N. Significantly higher fracture resistance was found for the groups with Fp (p<0.001). CONCLUSION: There was no statistically significant interaction between the "Fp" and "post" factors (p = 0.954). The ferrule preparation increased the fracture resistance of endodontically treated teeth. However, the use of glass fiber post showed no significant influence on the fracture resistance.