ASSESSMENT OF TORSION RESISTANCE OF GLIDE PATH ROTARY INSTRUMENTS

NiTi endodontic instruments for glide path are the most susceptible to fractures inside the root canal, mainly as a result of high torsional stress. Objective: The present study investigated the resistance to torsion and angular deflection of instruments destined for the glide path: ProGlider #16.02; T-File #17.02 and the MK Life #16.02. Materials and methods: Thirty rotating NiTi glide path instruments (n=10) with 25mm lengths were selected. The torsion test was performed based on ISO 3630-01 (1992). Three millimeters from the tip of the instruments, it was attached to a small load cell by a lever arm connected to the torsion shaft. Torsional strength and angular deflection were evaluated. Fracture surfaces were examined by scanning electron microscopy with magnifications of 1000x and 5000x in the cross section, and 50x in the lateral section. Statistical analysis was performed using the Kruskal-Wallis H test, followed by the Down's post hoc test. Results: The ProGlider instrument showed greater torsional strength (p<0.05) compared to the T-File (p<0.05) and MK Life (p<0.05), respectively. However, the T-File showed greater angular deflection (p<0.05) than the other groups tested. Conclusion: It can be concluded that the ProGlider instrument presented greater torque for the fracture, while the T-File instrument presented greater angular deflection.

Remoção de obturações endodônticas de Endosequence BC/CPoint em canais radiculares curvos usando instrumentos rotatórios ou reciprocantes / Removal of Endosequence BC/CPoint endodontic fillings in curved root canals using rotary or reciprocating instruments

Objetivo: O presente estudo usou micro-CT para avaliar a quantidade de material obturador remanescente em canais radiculares curvos que tinham sido obturados com cimento Endosequence BC/Cpoint ou com cimento AH/ guta-percha, depois do retratamento utilizando instrumentos rotatórios ou reciprocantes. Métodos: Sessenta canais mesiovestibulares de molares superiores foram instrumentados até MTwo #35.04. As amostras foram randomicamente alocadas em quatro grupos (n=15): os canais do G1 e G2 foram obturados com AH/guta-percha, e os canais do G3 e G4 foram obturados com BC/Cpoint. O material obturador foi removido usando instrumentos rotatórios ou reciprocantes ­ G1 e G3: R25 Reciproc + reinstrumentação com R40; e G2 e G4: Sistema ProTaper Universal Retratamento + reinstrumentação com MTwo 40.06. Micro-CTs foram usadas para medir a quantidade de material obturador remanescente (mm3 ) para o canal inteiro e para cada terço, em dois momentos: 1) após a remoção do material obturador; e 2) após a reinstrumentação. Resultados: Após a remoção do material obturador, BC/CPoint permaneceu mais dentro do canal do que AH/guta-percha quando o canal inteiro (29,92% x 19,25%, p=0,0290) e o terço apical foram analisados. Após a reinstrumentação, BC/CPoint permaneceu mais do que AH/guta-percha somente no terço apical. Protocolos de tratamento com instrumentos rotatórios ou reciprocantes removeram material obturador sem diferença para AH/guta-percha (G1 e G2: p> 0,05) e BC/CPoint (G3 e G4: p> 0,05). Conclusões: BC/Cpoint é mais difícil de ser removido de canais radiculares curvos do que AH/guta-percha. Instrumentos rotatórios e reciprocantes têm habilidade similar na remoção de material obturador (AU).

Objective: This study used micro-CT to evaluate the amount of remaining filling material in curved root canals obturated with Endosequence BC Sealer/Cpoint or AH/gutta-percha after a rotary or reciprocating retreatment. Methods: Sixty mesiobuccal canals of maxillary molars were instrumented up to MTwo #35.04. Samples were randomly assigned to four groups (n=15): canals from G1 and G2 were filled with AH/gutta-percha, and canals from G3 and G4 were filled with BC/Cpoint. Filling material was removed using rotary or reciprocating instruments: G1 and G3: R25 Reciproc + re-shaping with R40; and G2 and G4: ProTaper Universal Retreatment system + re-shaping with MTwo 40.06. Micro-CT was used to measure the remaining amount of filling material (mm3 ), for the whole canal, and for each third, in two moments: 1) after filling removal and 2) after canal re-shaping. Results: After filling removal, BC/CPoint remained more into the canal than AH/Gutta-percha when the whole canal (29.92% x 19.25%, p = 0.0290) and the apical third were analyzed. After re-shaping, BC/CPoint remained more than AH/Gutta-percha only in the apical third. Rotary or reciprocating retreatment protocols removed filling material without difference for AH/gutta-percha (G1 and G2: p > 0.05) and BC/CPoint (G3 and G4: p > 0.05). Conclusion: BC/Cpoint is more difficult to be removed from curved root canals than AH/gutta-percha. Reciprocating and rotary instruments have similar ability to remove filling material (AU).

Interference of coronal enamel and dentin thickness and ambient light on pulse oximetry interpretation

Abstract This study evaluated the interference of enamel and coronal dentin thickness and ambient light in pulse oximetry interpretation, using SaO2the human finger as a reference. Forty-two intact human permanent mandibular molars were sectioned mesiodistally in the central portion. Buccal and lingual dentin surfaces were drilled, and 4 mm, 3 mm and 2 mm enamel/dentin thicknesses were interposed between finger and device, after which SaO2 levels were measured by finger pulse oximetry. A reference device was designed to align pulse oximeter light-emitting diode, buccal surface of tooth, little finger, lingual surface of tooth and photodiode. Variables were described as means and standard deviation, and the confidence interval was reported. Repeated measures analysis of variance (ANOVA) was used to compare the groups, followed by Bonferroni correction. Student t test for paired samples was used to determine presence of ambient light (α = 0.05). Mean SaO2 level was lower at 4.0 ± 0.2 mm thickness, regardless of presence or absence of ambient light (92.7% and 89.3%). The other thicknesses yielded values of 95.5% and 94.5% at 3.0 ± 0.2 mm, and 96.4% and 96.0% at 2.0 ± 0.2 mm (p < 0.001). There were significant differences between SaO2 values at 4.0 ± 0.2 mm, 3.0 ± 0.2 mm and 2.0 ± 0.2 mm thicknesses, in the presence of ambient light. Mean SaO2 level in positive control was 96.3%, and mean pulse rate was 69.5 bpm in presence of ambient light; in the absence of light, these values were 96% and 70.5 bpm. Enamel and dentin thickness interfere with SaO2, regardless of presence or absence of ambient light. The lowest SaO2 levels were found for the thickest tooth samples.

Effect of dental bleaching on pulp oxygen saturation in maxillary central incisors - a randomized clinical trial

Abstract Objective To assess pulp oxygen saturation levels (SaO2) in maxillary central incisors after dental bleaching. Materials and Methods 80 participants (160 teeth) were randomly allocated to four groups: G1 In-office bleaching with two applications of 35% hydrogen peroxide (HP) (20 minutes), followed by at-home bleaching with 10% carbamide peroxide (CP) (2 hours/day for 16 days); G2 - Same protocol as G1, plus desensitizing toothpaste; G3 - In-office bleaching with 35% HP and one application of placebo gel (20 minutes), followed by at-home bleaching with 10% CP (2 hours/day for 16 days); and G4 - Same protocol as G3, plus desensitizing toothpaste. Pulp SaO2 levels were measured before (T0) and immediately after (T1) in-office bleaching; on the 5th (T2), 8th (T3), 12th (T4), and 16th days of at-home bleaching (T5); and on the 7th (T6) and 30th (T7) days. Mean (SD) pulp SaO2 levels were compared within groups by generalized estimating equations (GEE) and Student's t-test (P<0.05). Results Mean pulp SaO2 at T0 was 84.29% in G1, 84.38% in G2, 84.79% in G3, and 85.83% in G4. At T1, these values decreased to 81.96%, 82.06%, 82.19%, and 81.15% in G1, G2, G3, and G4 respectively, with significant difference in G4 (P<0.05). During home bleaching, pulp SaO2 levels varied in all groups, with 86.55%, 86.60%, 85.71%, and 87.15% means at T7 for G1, G2, G3, and G4, respectively; G2 presented significant difference (P<0.05). Conclusions Pulp SaO2 level in maxillary central incisors was similar at baseline, reducing immediately after in-office bleaching, regardless of using desensitizing toothpaste and increasing at 30 days after dental bleaching.

Effect of at-home bleaching on oxygen saturation levels in the dental pulp of maxillary central incisors

Abstract The present study assessed oxygen saturation (SaO2) levels before, during, and after at-home bleaching treatment in the pulps of healthy maxillary central incisors. SaO2 levels were measured in 136 healthy maxillary central incisors using a pulse oximeter. The bleaching protocol consisted of 10% carbamide peroxide gel placed in individual trays and used for four hours daily for 14 days. SaO2 levels were assessed before bleaching (T0), immediately after the first session (T1), on the 7th day of treatment (T2), on the 15th day (the day following the last session) (T3), and 30 days after completion of the bleaching protocol (T4). Data were statistically analyzed using generalized estimating equations (GEE), Student's t test (p<0.05) and Pearson's correlation. Mean pulp SaO2 levels were 85.1% at T0, 84.9% at T1, 84.7% at T2, 84.3% at T3, and 85.0% at T4. Gradual reductions in SaO2 levels were observed, with significant differences (p<0.001) during the course of home bleaching treatment. However, 30 days after the end of the bleaching protocol, SaO2 levels returned to baseline levels. Home bleaching caused a reversible transient decrease in SaO2 levels in the pulps.

Resumo Este estudo verificou o grau de saturação de oxigênio (SaO2) pulpar antes, durante e após o clareamento dental caseiro em incisivos centrais superiores hígidos. O nível de SaO2 foi verificado em 136 incisivos centrais superiores hígidos usando oxímetro de pulso. A técnica de clareamento empregou peróxido de carbamida 10% em moldeira individual por quatro horas diárias durante 14 dias. Os níveis de SaO2 foram analisados antes do clareamento (T0), imediatamente após a primeira sessão (T1), no sétimo dia de tratamento (T2), no décimo quinto dia (um dia após a última sessão) (T3) e 30 dias após o término do clareamento dental (T4). A análise estatística utilizou o modelo de equações de estimações generalizadas (GEE), teste t de Student (p<0,05) e correlação de Pearson. Os níveis médios de SaO2 pulpar foram 85,1% em T0, 84,9% em T1, 84,7% em T2, 84,3% em T3 e 85,0% em T4. Foi observada uma redução gradual dos níveis de SaO2, com diferenças significantes (p<0,001) durante o clareamento dental caseiro. No entanto, 30 dias após o término do clareamento dental, houve retorno aos valores iniciais. O clareamento dental caseiro provocou uma diminuição transitória reversível no grau de SaO2 pulpar.

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.

Tissue characterization following revascularization of immature dog teeth using different disinfection pastes

Abstract Revascularization of immature teeth with necrotic pulps traditionally involves the use of triple antibiotic paste, which may sometimes lead to undesirable complications. The objective of this study was to assess tissue repair in immature dog teeth with apical periodontitis subjected to revascularization, comparing two different pastes used for root canal disinfection. Apical periodontitis was induced in 30 dog premolars. Teeth were randomly divided into three experimental groups: root canals filled with triple antibiotic paste (n = 10); root canals filled with 1% propolis paste (n = 10); and no medication (n = 10). An additional group (n = 10, no intervention) was used as control. After 7 months, the jaws were histologically evaluated for the following variables: newly formed mineralized tissue (present/absent); vital tissue in the canal space (absent/periodontal ligament-like/pulp-like); apical extension of root (present/absent); and severity of inflammatory process (absent/mild/moderate/severe). There were no statistically significant differences among the experimental groups in new mineralized tissue formation and apical root development. The formation of vital tissue in the canal space, in turn, was statistically different between the triple paste and propolis groups: vital tissues were present in all revascularized teeth disinfected with propolis paste (100%), compared to 71% of those disinfected with the triple paste. Severity of inflammatory process was different between the triple paste and no medication groups. The new tissues formed onto canal walls and in the root canal space showed characteristics of cementum and periodontal ligament, respectively. Propolis may have some advantages over the triple paste for the revascularization of immature teeth.

Endodontic retreatment: Analysis of three specialists' retreatment rates / Retratamento endodôntico: avaliação dos índices de três especialistas

Endodontic retreatment is a clinical intervention intended to correct errors that have occurred in a treatment performed previously. There are several causes of failures. The anatomical variations between root canals and the diffi culties of achieving microbial disinfection are reported as two of the main causes. However, in the dental offi ces of both general practitioners and specialists, it is very common that the causes of indications for endodontic retreatment are technical failures due to poorly executed treatment. In view of this, the objective of this study is to analyze the records of three specialists in Endodontics and analyze the causes for referral of their endodontic retreatment patients. Examination of 24,553 treatments conducted over varying periods revealed that cases of retreatment accounted for a considerable proportion of the routine work performed by these specialists, at an average of 23% of cases. The majority of retreatment indications were due to technical failure of the initial treatment, in combination with microbial factors caused by contamination of coronal restorations and poorly executed endodontic preparation and fi lling.

O retratamento endodôntico é uma intervenção clínica destinada para a correção de falhas ocorridas num tratamento anteriormente realizado. Vários são os motivos desencadeadores de insucessos. A variedade anatômica dos canais radiculares e a difi culdade de proporcionar a desinfecção microbiana são referenciadas como duas das causas principais. Entretanto, nos consultórios dentários de clínicos gerais e especialistas, é muito comum a indicação para oretratamento endodôntico por razões técnicas devido a sua mal execução. Estabelecida esta problemática, o objetivo deste estudo consiste em avaliar os prontuários de três especialistas em endodontia e verifi car quais são os motivos de encaminhamentos de seus pacientes para o retratamento endodôntico. Após o exame de 24.553 tratamentos em períodos distintos, verifi couse que os casos de retratamentos chegam a uma média relevante de 23% na rotina destes especialistas e que a maioria das indicações se deram por inabilidade no primeiro tratamento, aliadas ao fator microbiano causado por contaminações de restaurações coronárias, preparos e obturações endodônticas mal executadas.

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...

Influence of pulp condition on the accuracy of an electronic foramen locator in posterior teeth: an in vivo study

The aim of this study was to assess, in vivo, the accuracy of the NovApex® electronic foramen locator in determining working length (WL) in vital and necrotic posterior teeth. The NovApex®was used in 144 canals: 35 teeth with vital pulps (68 canals) and 42 teeth with necrotic pulps (76 canals). WL was measured with the NovApex® locator and confirmed using the radiographic method. Differences between electronic and radiographic measurements ranging between 0.0 and 0.4 millimeters were classified as acceptable; differences equal to or greater than 0.5 millimeter were considered unacceptable. Pearson's chi-square test was used to assess the influence of pulp condition on the accuracy of NovApex®(a = 0.05). Regardless of pulp condition, differences between electronic and radiographic WL measurements were acceptable in 73.61% of the canals. No statistically significant differences in accuracy were observed when comparing vital and necrotic canals (p > 0.05). There were 38 unacceptable measurements. In none of these cases was the file tip located beyond the radiographic apex; in 32, it was located short of the NovApex® measurement. Pulp condition had no significant effect on the accuracy of NovApex®.

Histopathological analysis of corticosteroid-antibiotic preparation and propolis paste formulation as intracanal medication after pulpectomy: an in vivo study

Intracanal medication in pulpectomy therapy is used between appointments with the objective of reducing pain and inflammatory processes in pulp and periapical tissues. Propolis has been known as a natural antibiotic and has been subject of medical and dental research due to its therapeutic properties such as antibiotic, analgesic and anti-inflammatory effects. OBJECTIVE: The aim was to carry out an in vivo evaluation of the periapical tissue response to propolis paste when used as an intracanal medication in the teeth of dogs after pulpectomy. MATERIAL AND METHODS: 72 dog's incisors were selected for the experiment. After biomechanical preparation the root canal was filled with a corticosteroid-antibiotic preparation, experimental propolis paste, non-medicament (negative control) or non-pulpectomy at all (positive control). The medications were left inside the root canal for 7, 14 or 28 days. At the end of the experimental period histological sections were prepared and all laboratories processes for Harris hematoxylin and eosin staining was proceeded followed by the analysis using an optical microscope. Sections were classified according to a score representing the inflammatory events observed: the presence of polymorphonuclear neutrophils, polymorphonuclear eosinophils, lymphocytes and plasma cells, macrophages and/or giant cells, fibrous condensation and abscesses. RESULTS: There were statistically significant differences between the tissue reactions caused by the two substances being tested, after different experimental periods, with the periapical tissue that was in contact with propolis paste exhibiting fewer inflammatory reactions in comparison to corticosteroid-antibiotic preparation. CONCLUSIONS: The low tissue responses from propolis paste suggest that this material could be considered as an option for root canal medication after pulpectomy.

Conhecimento dos professores de educação física sobre o atendimento de emergência da avulsão dentária / Knowledge of physical education teachers about emergency management of tooth avulsion

A great number of traumatic dental injuries occur at school, during sports-related activities. However, physical education teachers are often not prepared to provide emergency management of dental trauma in general and of tooth avulsion in particular. The aim of this study was to assess the knowledge of emergency management of tooth avulsion among physical education teachers at public and private schools of a city in southern Brazil. A questionnaire covering personal and professional information and eight multiple-choice questions to assess knowledge of emergency management of tooth avulsion was sent to 217 physical education teachers. Of a total of 217 questionnaires distributed, 102 returned. Only 23.5% of the teachers had received prior information on dental trauma. When asked about the first action to be taken if faced with an avulsed tooth, only 12.7% informed they would attempt to replant the tooth. Fifty two teachers (51%) were not aware of the optimum extraoral time. Significant differences were found between teachers who had and who had not received prior information with regard to adequate transport medium and adequate time for replantation (chi-square, p = 0.03 and p = 0.02, respectively). There is a general lack of knowledge of emergency management of avulsed teeth among physical education teachers, pointing to an urgent need to implement regular, continuing education so as to increase the level of knowledge and improve prognosis of this important traumatic dental injury.

Grande parte dos traumatismos dentários ocorre no ambiente escolar durante a prática de esportes. Porém, os professores de educação física não estão preparados para fornecer o tratamento de emergência adequado, que é essencial para o prognóstico do dente avulsionado. O objetivo deste estudo foi investigar o conhecimento dos professores de educação física das escolas estaduais, municipais e particulares na cidade de Santa Maria-RS-Brasil sobre o atendimento de emergência da avulsão dentária. Um questionário avaliando o conhecimento dos professores de educação física foi distribuído a 217 professores. Um total de 102 (47%) questionários retornaram e foram analisados. Os resultados mostraram que apenas 23,5% dos professores já tinham recebido informações sobre traumatismo dentário. Quando questionados sobre os primeiros cuidados com o dente avulsionado, somente 12,7% tentariam reimplantar. Cinqüenta e dois professores (51%) não souberam por quanto tempo o dente pode permanecer fora do alvéolo sem causar danos às células do ligamento periodontal. O teste Qui-quadrado indicou uma diferença significante entre os professores que receberam ou não informação quanto ao tempo hábil para o reimplante (p=0,02). Fica evidente que há um inadequado conhecimento sobre o tratamento de urgência de dentes avulsionados. O estudo aponta para a necessidade de educação continuada para aumentar o conhecimento sobre o manejo de urgência de dentes avulsionados.

Flexibility of K3 and ProTaper universal instruments

This study used a mechanical test to evaluate the flexibility of instruments from the K3 (conicity 0.04) and the ProTaper Universal systems when they were new and after 5 uses in simulated canals. Five sets of instruments of each system were tested: K3 (15, 20, 25, 30, 35, 40 and 45) and ProTaper Universal (S1, S2, F1, F2, F3, F4 and F5). Each set of instruments was used to prepare a simulated canal and the same set of instruments was used 5 times (50 canals). The number of each subgroup represented the number of uses: 0 (control), 1, 3 and 5 uses. Before and after each use, the instruments were submitted to a mechanical flexibility test performed in a Versat 502 universal testing machine. Interactions between the instrument and the number of uses were analyzed by ANOVA and Tukey's test at a 5 percent level of significance. Instruments from both systems presented lower flexibility after the third use compared to the flexibility obtained after uses 0 and 1 (p<0.05), and maintained the same flexibility after the fifth use. The flexibility of instruments from the K3 system decreased with the increase of diameter, irrespective of the number of uses. Among the instruments from the ProTaper Universal system, the shaping files presented greater flexibility than the finishing files. F2 and F3 were the least flexible instruments, and F4 and F5 presented flexibility values similar to those of F1.

Esta pesquisa estudou a flexibilidade de instrumentos do Sistema K3 (conicidade 0.04) e do Sistema ProTaper Universal, por meio de um teste mecânico, quando os instrumentos eram novos e após 5 usos em canais simulados. Cinco jogos de instrumentos de cada sistema foram testados, como segue: grupo I - K3 (15, 20, 25, 30, 35, 40 e 45), e grupo II - ProTaper Universal (S1, S2, F1, F2, F3, F4 e F5). Cada jogo de instrumento foi usado para preparar um canal simulado, e o mesmo jogo de instrumento foi usado 5 vezes (50 canais). O número de cada subgrupo representou o número de usos: 0 (controle), 1, 3 e 5 usos. Antes do uso e depois de cada uso os instrumentos foram submetidos a um teste mecânico de flexibilidade realizado na máquina de ensaios universais Versat 502. A interação entre o instrumento e o número de usos foi analisada pelo ANOVA e pelo teste de Tukey ao nível de significância 5 por cento. Instrumentos de ambos os sistemas apresentaram menor flexibilidade após o terceiro uso quando comparada com a flexibilidade após os usos 0 e 1 (p<0,05), e mantiveram a mesma flexibilidade após o quinto uso. A flexibilidade dos instrumentos do sistema K3 diminuiu conforme o aumento de diâmetro, independente do número de usos. Entre os instrumentos do sistema ProTaper Universal, os shaping apresentaram maior flexibilidade que os finishing. F2 e F3 foram os menos flexíveis e F4 e F5 apresentaram valores de flexibilidade similares ao F1.

CT evaluation of apical canal transportation associated with stainless steel hand files, oscillatory technique and ProTaper rotary system

This study used computed tomography (CT) to compare apical canal transportation in mesiobuccal canals of maxillary molars prepared with different techniques. Sixty teeth were assigned to 3 groups (n=20), according to the technique used for root canal instrumentation: hand instrumentation with K-Flexofiles, K-Flexofiles activated by an oscillatory system and ProTaper NiTi rotary system. Pre and post-instrumentation CT images were obtained 3 mm short of the apical foramen and were superimposed to compare canal transportation. Data were analyzed statistically by ANOVA and Tukey's test using the SPSS software (α=0.05). In the buccal direction, the manual technique produced significantly less canal transportation than the oscillatory technique (p<0.05) and both were similar to the rotary technique (p>0.05). In the distal and distopalatal directions, the oscillatory technique produced more canal transportation (p<0.05). In the mesiopalatal direction, the oscillatory technique produced more canal transportation than the manual technique (p<0.05), and both were similar to the rotary technique (p>0.05). In conclusion, all techniques produced canal transportation, and the oscillatory technique produced the greatest removal of root dentin toward the innerside of the root curvature.

Este estudo utilizou a tomografia computadorizada (TC) para comparar o transporte do canal radicular nos canais mésio-vestibulares de molares superiores preparados por diferentes técnicas. Sessenta molares superiores foram divididos em 3 grupos (n=20) de acordo com a técnica utilizada para o preparo do canal radicular: instrumentação manual com limas K-Flexofile, limas K-Flexofile acopladas a um sistema oscilatório e sistema rotatório ProTaper. Imagens de TC pré e pós-instrumentação foram obtidas 3 mm aquém do forame apical e superpostas para comparar o transporte do canal. Os dados foram analisados estatisticamente pela Análise de Variância (ANOVA) e Teste de Tukey utilizando o software SPSS (α=0,05). Na direção vestibular, a técnica manual produziu significantemente menos transporte do canal radicular do que a técnica oscilatória (p<0,05) e ambas foram similares a técnica rotatória (p>0,05). Nas direções distal e disto-palatina, a técnica oscilatória produziu mais transporte do canal radicular (p<0,05). Na direção mésio-palatina, a técnica oscilatória produziu mais transporte do canal radicular do que a técnica manual (p<0,05), sendo que ambas foram similares à técnica rotatória (p>0,05). Em conclusão, todas as técnicas produziram transporte do canal radicular e a técnica oscilatória produziu os maiores desgastes de dentina na direção interna da curvatura.

Effect of endodontic preflaring on electronic determination of working length / Efeito do pré-alargamento endodôntico na determinação eletrônica do comprimento de trabalho

PURPOSE: To evaluate the effect of preflaring on the electronic measurement of working length in mesiobuccal roots of maxillary molars. METHODS: Thirty roots were embedded in an alginate model. Root canals were irrigated with 2.5 percent sodium hypochlorite, and a size 10 K file was inserted into the canal until the locator indicated that apical constriction had been reached. Then, the cervical portion of each canal was flared using the ProTaper system shaping files, whereupon electronic measurements were carried out again. RESULTS: The Student's t test for paired samples did not reveal statistically significant differences in the measurements obtained for preflared and unflared canals (P<0.05). CONCLUSION: Based on the lack of clinical significant relevance of the comparisons carried out in the present study, it is possible to conclude that electronic working length measurement can be carried out either before or after cervical preparation.

OBJETIVO: Avaliar o efeito do pré-alargamento sobre a medição eletrônica do comprimento de trabalho em raízes mésio-vestibulares de molares superiores. METODOLOGIA: Trinta raízes foram incluídas em um modelo de alginato. Canais radiculares foram irrigados com hipoclorito de sódio a 2,5 por cento, e uma lima de tamanho 10 K foi inserida no canal até onde o localizador indicou que a constrição apical tinha sido alcançada. A porção cervical de cada canal foi alargada usando as limas do sistema ProTaper, quando então as medições eletrônicas foram realizados novamente. RESULTADOS: O teste t de Student para amostras pareadas não mostrou diferenças estatisticamente significativas nas medições obtidas para canais pré-alargados e não alargados (P<0,05). CONCLUSÃO: Com base na falta de relevância clínica significativa das comparações realizadas no presente estudo, é possível concluir que a medição do comprimento eletrônico de trabalho pode ser realizado antes ou após o preparo cervical.

Utilização de instrumentos rotatórios de níquel-titânio por endodontistas do Rio Grande do Sul, Brasil

Objetivo: avaliar o uso de instrumentos rotatórios de níquel-titânio entre endodontistas do Rio Grande do Sul.Métodos: uma pesquisa foi realizada com todos os endodontistas cadastrados no Conselho Regional de Odontologia(CRO) desse estado. Resultados: um total de 430 questionários foi enviado pelos Correios, sendo que 106 retornaram (taxa de resposta: 25%). A grande maioria dos entrevistados (88,7%) informou já ter utilizado instrumentos rotatórios de níquel-titânio; desses, 44,3% receberam treinamento durante o curso de especialização. As principais vantagens associadas à instrumentação rotatória, em relação à manual, foram menor fadiga para o profissional/maior conforto para o paciente (29%); e instrumentação mais rápida (24,9%). O preço/custo foi a razão mais frequente para não usar ou parar de usar o sistema (55,8%e 59,3%, respectivamente). O problema mais frequentemente relatado foi a fratura da lima (54%). O maior tempo trabalhando como endodontista influenciou negativamente no uso dos instrumentos (p = 0,03), mas não afetou a ocorrência de fratura da lima. Conclusões: a maioria dos endodontistas do Rio Grande do Sul utiliza e reconhece os benefícios da instrumentação rotatória. No entanto, os altos custos envolvidos e a alta frequência de fratura da lima impedem um uso mais amplo dessa tecnologia

Endodontic treatment of a 36-mm long upper cuspid: clinical case report / Tratamento endodôntico de canino superior medindo 36 mm de comprimento: relato de um caso clínico

Purpose: To report a clinical case of a 36 mm long upper cuspid submitted to root canal treatment, with emphasis on the alternative technique employed. Case description: A 32 years old, male patient had suffered subluxation of teeth 12 and 13 and coronal fracture involving enamel and dentin, as well as pulp exposition, of tooth 14 because of a motorcycle accident. The man was given dental assistance and a semi-rigid splinting of teeth numbers 12 and 13 was carried out followed by the root canal treatment in a single visit on tooth no. 14. At 30-day follow-up pulp necrosis was detected in teeth 12 and 13 and the root canal treatment was implemented. The tooth 13 was 36 mm long and since the longest possible file (31 mm) was already in use, the cervical limit of the access cavity was considered as the reference point. Conclusion: This technique not only provided adequate disinfection, preparation and filling of the root canal, but it also allowed preservation of the remaining tooth structure.

Objetivo: Descrever o tratamento endodôntico de um canino superior medindo 36 mm de comprimento, mostrando a técnica empregada no preparo do canal radicular e obturação. Descrição do Caso: Paciente do sexo masculino, com 32 anos de idade, sofreu subluxação dos dentes 12 e 13 e fratura coronária envolvendo esmalte e dentina, com exposição pulpar do dente 14, devido a um acidente de moto. No atendimento de urgência, foi realizada a contenção semirrígida dos dentes 12 e 13, seguida da endodontia em sessão única do dente 14. Trinta dias após, foi diagnosticada necrose pulpar dos dentes 12 e 13 e sua endodontia foi, então, iniciada. O comprimento aparente do dente 13 foi estabelecido em 36 mm e como o instrumento mais longo que dispomos no mercado possui 31 mm, o limite cervical da cavidade de acesso foi usado como bordo de referência. Conclusão: Além de garantir uma correta sanificação, modelagem e obturação do canal, esta técnica também permitiu a preservação da estrutura dental remanescente.

Microscópio operatório na Endodontia: magnificação visual e luminosidade / Operating microscope in Endodontics: visual magnification and luminosity

Introdução: O microscópio operatório vem sendo utilizado na Endodontia com o intuito de minimizar a obscuridade do campo operatório, pois proporciona alta magnificação e luminosidade, favorecendo os procedimentos realizados e proporcionando um resultado de maior qualidade. Objetivo e revisão de literatura: O objetivo deste trabalho foi revisar a literatura discorrendo sobre a situação atual da microscopia operatória na Endodontia, com ênfase em suas vantagens e limitações. Apesar de ser um instrumento tecnológico de custo relativamente elevado e necessitar de um período de aprendizagem e adaptação, o uso desse aparato tem se difundido gradativamente. Conclusão: A importância da magnificação está embasada cientificamente na Odontologia, de tal forma que o seu uso proporcionou à Endodontia uma melhora significativa na visão e na iluminação do campo operatório, oferecendo trabalhos de melhor qualidade com proporcionais índices de sucesso nos tratamentos, além de melhorar a comunicação entre profissionais e entre profissionais e pacientes e auxiliar na documentação legal para fins jurídicos.

Introduction: The surgical microscope has been used in Endodontics in order to minimize the obscurity of the surgical , because it provides a high magnification and luminosity, thereby enhancing the procedures performed and providing a final result of higher quality. Objective and literature review: The objective of this study was to review the literature by addressing the current situation of the operating microscope in Endodontics, emphasizing its advantages and limitations. Despite being a technological tool that is relatively costly and that requires a period of learning and adaptation, the use of this apparatus has been spreading gradually. Conclusion: The importance of magnification is scientifically based in Dentistry, in such a way that its use has provided significant improvement to Endodontics with regards to vision and lighting of the operative , by offering better quality of work with proportional success rates in treatments, besides improving communication between professionals and patients and assisting in the documentation for legal purposes.

Comparative assessment of root canal preparation by undergraduate students using manual and automated devices / Avaliação comparativa do preparo do canal radicular realizado por alunos de graduação com os sistemas manual e oscilatório

Purpose: To evaluate the preparation of root canals performed by undergraduate students using manual and automated devices, based on the amount of dentin removed from the canal walls, the time required for preparation, and student´s opinions. Methods: Mesial roots of 20 human mandibular molars extracted for clinical reasons were used in the experiment. Twenty undergraduate students prepared two canals each, one using the manual method and the other using an automated device; following root canal preparation, the students filled out a questionnaire. Time was recorded throughout the procedures. Teeth were scanned with computed tomography before and after preparation. Images were superimposed and measured for the amount and area of dentin removed. Results: There was no difference between the use of manual and automated devices with regard to the amount of material removed. Distal walls presented a greater amount of material removed from the cervical third when compared with middle third in both techniques. There were no statistically significant differences between both techniques with regard to preparation time. Conclusion: The automated system represents an adequate alternative option as an auxiliary resource for undergraduate teaching in the preparation of root canals.

Objetivo: Avaliar o preparo do canal radicular realizado por alunos de graduação com os sistemas manual e oscilatório, considerando o desgaste produzido nas paredes do mesmo, o tempo de trabalho e a opinião dos estudantes. Metodologia: Foram utilizadas raízes mesiais de 20 molares inferiores humanos extraídos por indicação clínica. Vinte alunos de graduação realizaram o preparo de dois canais, um deles com o sistema manual e o outro com o sistema oscilatório, e posteriormente responderam a um questionário. O tempo foi registrado durante os preparos. Os dentes foram examinados por tomografia computadorizada antes e após o preparo. As imagens foram sobrepostas e as áreas de contorno demarcadas. Medidas lineares e da área de desgaste foram realizadas. Resultados: Não houve diferença entre as técnicas quanto à medida linear de desgaste. A parede distal apresentou maior desgaste no terço cervical do que no médio em ambas as técnicas. A área total de desgaste foi maior no terço cervical do que no médio. Com relação ao tempo de preparo, não houve diferença estatisticamente significante entre as duas técnicas. Conclusão: O sistema oscilatório constitui-se em um recurso auxiliar para o preparo do canal radicular no ensino de graduação.