Mesiolingual Canal Prevalence in Maxillary First Molars assessed through Different Methods.

AIM: Evaluate the prevalence of mesiolingual canal prevalence orifice in mesiobuccal roots of maxillary first molars using five methods of visualization. MATERIALS AND METHODS: About 73 first permanent maxillary molars were analyzed. Visual clinical analysis of the presence of the fourth canal was performed using a straight end-odontic exploratory probe (EXDG16®) and a K10 manual file (SybronEndo®). Dental elements that were not located on the fourth canal were analyzed with the aid of a magnifying glass (Zeiss®) with a 2.5-fold increase and those teeth in which the fourth canal was not found went through the examination with clinical surgical microscope (OPTO®) with magnification of 20 times with both the explorer and endodontic file. Next, a periapical radiography of the teeth was performed in the teeth in which the mesiolingual canal was not yet found to observe the presence or absence of the fourth canal. Afterward, the teeth in which the canal was not yet located were scanned using the microtomography equipment (SkyScan®), at 100 kV and 100 µA, with an isotropic resolution of 16 µm. RESULTS: The mesiolingual canal was located in 70 teeth (95.8%) and in only 3 teeth it was not identified. CONCLUSION: The visual method in the fourth canal search has limitations, whereas the composite magnifying glass, the clinical surgical microscopy, and the computerized microtomography are efficient methods for locating the fourth canal in the upper first molars. CLINICAL SIGNIFICANCE: The anatomical complexity of the first maxillary molars is one of the factors that leads to high failure rates in the endodontic treatments of this group of teeth. In most clinical situations, the mesiolingual canal goes unnoticed by professionals, since conventional radiographs do not always allow the visualization of all root canals. Determining an effective method for locating the mesiolingual canal is of paramount importance to the success of endodontic treatment.

Comparação da resistência à compressão entre materiais restauradores provisórios na endodontia: estudo in vitro / Comparison of compressive strength between temporary restorative materials in endodontics: in vitro study

Objetivo: este trabalho avaliou in vitro a resistência à compressão (RC) de diferentes materiais restauradores provisórios utilizados na endodontia: G1 (Vitremer®), G2 (Bioplic®), G3 (Coltosol ®) e G4 (IRM®). Material e método: Foram feitos 8 corpos de prova (n=8) de cada material totalizando 32 amostras (n=32) em matriz de silicone altura de 3,5mm e 6 mm de largura. Metade das amostras (n=16) foram mantidas 7 dias em soro fisiológico em estufa a 37ºC e a outra metade (n=16) mantidas por 14 dias e então foram submetidos ao ensaio de resistência a compressão, em uma máquina de Ensaios Universal (Emic 200) à velocidade de 0,5mm/min com uma célula de capacidade de carga de 200 kgf. Os dados obtidos em Mpa foram submetidos ao teste ANOVA a um critério, Tukey para comparações múltiplas (p<0,05) e por último T-test para amostras pareadas. Resultados: houve diferença estatisticamente significativa entre os grupos em 7 dias (p=0,000) sendo os grupos G1 e G2 iguais entre si (420,72 Mpa e 396,50 Mpa), porém em 14 dias não houve diferença entre os 4 grupos (p=0,104). O T-test mostrou a diferença entre os diferentes períodos de tempo dos grupos sendo G1 e G2 sem diferença estatística (p=0,178 e p=0,066), mas entre os grupos G3 e G4 houve diferença estatística (p=0,001 e p=0,000). Conclusão: O material a base de ionômero de vidro (Vitremer®) e a base de resina (Bioplic®) apresentaram os maiores valores em 7 dias. Em 14 dias os grupos não apresentaram diferenças estatísticas entre si, tiveram o mesmo comportamento apesar dos materiais à base de óxido de zinco (IRM® e Coltosol®) apresentarem maiores valores de resistência a compressão.

Objective: this study compared in vitro the compreesive strengt (CS) of the diferents materials used in endodontics: G1 (Vitremer®), G2 (Bioplic®), G3 (Coltosol®) e G4 (IRM®). Were made 8 specimens (n= 8) of each material, totalizing 32 samples (n=32) in a silicone matrix of 3,5mm height and 6mm diameter. Half the samples (n=16) was held 7 days in saline solution in an oven at 37ºC, and the other half (n=16) in 14 days and then subjected to the CS test in a universal machine (Emic 200), at a crosshead spreed of 0,5mm/min. Data in Mpa were submitted to one-way ANOVA, Tukey test for multiplex comparisons (p<0,05) and finally T-test for paired samples. Results: there was a statistically significant difference between the groups in 7 days (p=0,000), being the G1 and G2 equal to each other (420,72 Mpa e 396,50 Mpa), but in 14 days there was not a statically significant difference between the 4 groups (p=0,104). The T-test showed the difference between the different periods of the groups being G1 and G2 without statically difference (p=0,178 and p=0,066), between G3 and G3 groups there was significant differences (p=0,001 e p=0,000). Conclusion: materials based on glass ionomer (Vitremer®) and resinous (Bioplic®) showed higher values in 7 days. In 14 days the groups did not show statistically differences each other, had the same behavior dispite the fact that zinc oxide materials (Coltosol® and IRM®) had higher valuer of compressive strenght.

Comparação in vitro da sorção e da solubilidade de quatro materiais restauradores provisórios em endodontia / In vitro comparison of the sorption and solubility properties of temporary restorative materials used in endodontics

Objetivo: Este estudo comparou as propriedades de sorção e solubilidade de materiais restauradores provisórios utilizados em endodontia. Material e método: Foram confeccionados 60 corpos de prova, divididos em quatro grupos: G1-IRM® (Dentsply), G2- Coltosol® (Coltene), G3- Riva Light Cure® (SDI), G4 Clip F® (Voco) e pesados após 24h em balança analítica de precisão. Após, foram imersas em água destilada por 12 dias e pesados novamente. Retornaram à estufa a 37 °C por 24h. Resultados: Apresentaram diferenças estatisticamente significativas entre os grupos para sorção e solubilidade. O grupo G4 apresentou menor grau de sorção com diferença estatística dos demais grupos (0,0000087). Os níveis de sorção, encontrados nos grupos G3 (0,0000313) e G1 (0,0000493), apresentam- -se estatisticamente semelhantes entre si e o G2 (0,0000573) foi estatisticamente semelhante ao G1(0,0000493). Quanto à solubilidade, G1 (0,0000107) apresentou o menor nível com diferença estatística em relação aos demais grupos. Os valores de solubilidade, em ordem crescente, foram verificados respectivamente nos grupos G4 (-0,0000213), G3 (-0,000064) e G2 (-0,0002693). Conclusões: 1. Materiais provisórios fotoativados apresentaram os menores resultados quanto à sorção de água; 2. Compostos à base de óxido de zinco e eugenol apresentaram o menor nível de solubilidade comparado com todos os outros materiais provisórios e 3 - compostos livres de eugenol de uso imediato obtiveram os maiores valores tanto de sorção quanto de solubilidade.

Objective: This study compared the sorption and solubility properties of temporary restorative materials used in endodontics. Material and method: 60 specimens were divided into four groups: G1-IRM® (Dentsply), G2-Coltosol® (Coltene), G3-Riva Light Cure® (SDI), G4 Clip F® ) and weighed after 24 hours in precision analytical balance scale. Afterwards, they were immersed in distilled water for 12 days and weighed again. They returned to the stove at 37 ° C for 24 hours. Results: There were statistically significant differences between the groups for sorption and solubility. The G4 group presented lower degree of sorption with statistical difference of the other groups (0.0000087). The sorption levels, found in groups G3 (0.0000313) and G1 (0.0000493), were statistically similar to each other and G2 (0.0000573) was statistically similar to G1 (0.0000493). Regarding solubility, G1 (0.0000107) presented the lowest level with statistical difference in relation to the other groups. The solubility values, in ascending order, were respectively verified in groups G4 (-0.0000213), G3 (-0.000064) and G2 (-0.0002693). Conclusion: 1. Temporary photoactivated materials presented the lowest results regarding sorption of water; 2. Compounds based on zinc oxide and eugenol showed the lowest level of solubility compared to all other provisional materials and 3. eugenolfree compounds of immediate use obtained the highest values of both sorption and solubility.

Apical Transportation, Centering Ratio, and Volume Increase after Manual, Rotary, and Reciprocating Instrumentation in Curved Root Canals: Analysis by Micro-computed Tomographic and Digital Subtraction Radiography.

INTRODUCTION: This study aimed to evaluate apical transportation (AT), centering ratio (CR), and volume increase (VI) produced after instrumentation of mesiobuccal canals of maxillary molars with hand files, rotary, and reciprocating instruments using micro-computed tomographic (micro-CT) imaging and to demonstrate the ability of digital subtraction radiography (DSR) to evaluate AT. METHODS: Forty-five canals were randomly assigned to either group K, manual K-files; PTN, ProTaper Next (Dentsply Maillefer, Ballaigues, Switzerland); or Rec, Reciproc (n = 15 for each group) for preparation. Master apical files were #25, X2 (#25/06), and R25 (#25/08), respectively. Micro-CT imaging was used to measure AT (mm) and CR (mm) at 3 different locations (1, 4, and 7 mm from the apex). VI (mm3) was measured for each root third and for the whole canal. DSR (mesiodistal and buccolingual projections) was used to measure AT at 1 mm from the apex. RESULTS: AT and CR values were statistically similar across the groups at 1, 4, and 7 mm. AT results obtained for the different locations were similar within each group; CR, in turn, showed statistically lower values at 1 mm. VI was statistically similar in all groups. Both DSR and micro-CT imaging showed that AT always occurred on the outside of canal curvature. The highest mean value obtained for AT was 0.215 mm. CONCLUSIONS: AT, CR, and VI were similar for the K, PTN, and Rec groups. AT results were clinically irrelevant. DSR was as effective as micro-CT imaging in AT analysis and could be considered as an alternative method for assessing this outcome.

Eficácia dos sistemas de retratamento ProTaper Universal® e D-RaCe® na remoção de material obturador: estudo in vitro utilizando subtração radiográfica digital / Effectiveness of ProTaper Universal® and D-RaCe® retreatment files in the removal of root canal filling material: an in vitro study using digital subtraction radiography

Comparar a eficácia dos sistemas de retratamento ProTaper Universal®, D-RaCe® NiTi e Hedstrõem na remoção de material obturador de canais curvos. Metodologia: Um total de 39 primeiros molares inferiores foram selecionados, e seus canais mesiobucais (MB) foram utilizados. Os dentes foram atribuídos a um entre três grupos idênticos (n = 13 por grupo), de acordo com a técnica de remoção do material: G1 – ProTaper Universal® (D1, D2, D3); G2 – D-RaCe® (DR1, DR2); ou G3 – Hedstrõem (35, 30, 25, 20). Em todos os grupos, instrumentos complementares foram usados no repreparo. Imagens de subtração radiográfica digital foram obtidas sobrepondo a primeira radiografia, obtida após o preenchimento do canal, à segunda, obtida após a remoção do material, em projeções bucolingual (BL) e mesiodistal (MD). Dados quantitativos foram analisados usando coeficientes de correlação intraclasse e os testes não paramétricos de Kruskal-Wallis e Friedman (p ≤ 0,05). Resultados: A comparação entre os grupos não detectou diferenças na remoção do material obturador entre os dentes preparados utilizando os sistemas ProTaper Universal®, D-RaCe®, ou Hedstrõem nos terços cervical e médio (nas projeções BL ou MD). No terço apical (projeção MD), o sistema ProTaper Universal® produziu os melhores resultados; já os instrumentos Hedstrõem mostraram os piores resultados (projeção MD). As comparações intragrupo mostraram que o terço cervical era o mais limpo, e que o terço apical era o menos limpo, nos grupos tratados tanto com ProTaper Universal® quanto com D-RaCe® (projeção MD); no grupo tratado com instrumentos Hedstrõem, menos material obturador foi removido à medida que os canais se aproximavam do terço apical (projeções MD e BL). Conclusões: Nossos resultados indicam que o sistema ProTaper Universal® é a melhor escolha para a remoção de material obturador, combinado com instrumentação suplementar para a obtenção de melhores resultados no terço apical...

To compare the effectiveness of the ProTaper Universal® Retreatment system, the D-Race® NiTi system and Hedstrõem files for removal of filling material from curved root canals. Methodology: A total of 39 first mandibular molars were selected and their mesiobuccal (MB) canals were used for the study. Teeth were assigned to one of three identical groups (n = 13 per group) according to removal technique: G1 – ProTaper Universal® Retreatment (D1, D2, D3); G2 – D-RaCe® (DR1, DR2); or G3 – Hedstrõem files (35, 30, 25, 20). In all groups, supplementary files were used for re-preparation. Digital subtraction radiography images were produced by superimposing the first radiograph, taken after filling the canal, over the second, taking after removal of the filling, in buccolingual (BL) and mesiodistal (MD) projections. Quantitative data were analyzed using intraclass correlation coefficients and the Kruskal-Wallis and Friedman non-parametric tests (p ≤ 0.05). Results: Comparison of groups detected no differences in filling removal between teeth in the ProTaper Universal® Retreatment, D-RaCe® or Hedstrõem file groups for the cervical or mid thirds (for either MD or BL projections). In the apical third (MD projection), ProTaper Universal® Retreatment produced the best results; and Hedstrõem files exhibited the worst results (MD projection). Intra-group comparisons showed that the cervical third was the cleanest and the apical third was the least well-cleaned, for the ProTaper Universal® Retreatment and D-RaCe® groups (MD projection), while less filling material was removed using Hedstrõem when the canals approached the apical third (MD and BL projections). Conclusions: Our findings indicate that the ProTaper Universal® Retreatment system is the best choice for endodontic filling material removal, combined with supplementary instrumentation to achieve better results in the apical third...