Accuracy of working length determination using 3 electronic apex locators and direct digital radiography.

OBJECTIVES: The objectives of this study were to assess the accuracy of working length determination using 3 electronic apex locators and direct digital radiography and to compare the results with those obtained using the visual method (control measurement). STUDY DESIGN: Twenty extracted human maxillary premolars were selected: 17 two-rooted and 3 single-rooted (total of 37 canals). Working length was measured using electronic apex locators Elements Diagnostic, Root ZX, and Just II. Subsequently, teeth were positioned in the alveolar bone of a dry skull and submitted to direct digital radiography. A variation of ±1 mm was considered as acceptable. Results were analyzed using the Wilcoxon and the χ(2) tests. RESULTS: Results presented an accuracy of 94.6% for Elements Diagnostic, 91.9% for Root ZX, 73.0% for Just II, and 64.9% for direct digital radiography when considering the margin of ±1 mm in relation to the control measurement. Comparisons with the actual control measurements resulted in accuracy results of 13.51%, 13.51%, 10.10%, and 2.70%, respectively. CONCLUSIONS: Root ZX and Elements Diagnostic are more accurate in determining working length when compared with Just II and Schick direct digital radiography.

Accuracy of three electronic apex locators in the presence of different irrigating solutions.

The present study compared the accuracy of three electronic apex locators (EALs) - Elements Diagnostic®, Root ZX® and Apex DSP® - in the presence of different irrigating solutions (0.9% saline solution and 1% sodium hypochlorite). The electronic measurements were carried out by three examiners, using twenty extracted human permanent maxillary central incisors. A size 10 K file was introduced into the root canals until reaching the 0.0 mark, and was subsequently retracted to the 1.0 mark. The gold standard (GS) measurement was obtained by combining visual and radiographic methods, and was set 1 mm short of the apical foramen. Electronic length values closer to the GS (± 0.5 mm) were considered as accurate measures. Intraclass correlation coefficients (ICCs) were used to verify inter-examiner agreement. The comparison among the EALs was performed using the McNemar and Kruskal-Wallis tests (p < 0.05). The ICCs were generally high, ranging from 0.8859 to 0.9657. Similar results were observed for the percentage of electronic measurements closer to the GS obtained with the Elements Diagnostic® and the Root ZX® EALs (p > 0.05), independent of the irrigating solutions used. The measurements taken with these two EALs were more accurate than those taken with Apex DSP®, regardless of the irrigating solution used (p < 0.05). It was concluded that Elements Diagnostic® and Root ZX® apex locators are able to locate the cementum-dentine junction more precisely than Apex DSP®. The presence of irrigating solutions does not interfere with the performance of the EALs.

Accuracy of three electronic apex locators in the presence of different irrigating solutions

The present study compared the accuracy of three electronic apex locators (EALs) - Elements Diagnostic®, Root ZX® and Apex DSP® - in the presence of different irrigating solutions (0.9 percent saline solution and 1 percent sodium hypochlorite). The electronic measurements were carried out by three examiners, using twenty extracted human permanent maxillary central incisors. A size 10 K file was introduced into the root canals until reaching the 0.0 mark, and was subsequently retracted to the 1.0 mark. The gold standard (GS) measurement was obtained by combining visual and radiographic methods, and was set 1 mm short of the apical foramen. Electronic length values closer to the GS (± 0.5 mm) were considered as accurate measures. Intraclass correlation coefficients (ICCs) were used to verify inter-examiner agreement. The comparison among the EALs was performed using the McNemar and Kruskal-Wallis tests (p < 0.05). The ICCs were generally high, ranging from 0.8859 to 0.9657. Similar results were observed for the percentage of electronic measurements closer to the GS obtained with the Elements Diagnostic® and the Root ZX® EALs (p > 0.05), independent of the irrigating solutions used. The measurements taken with these two EALs were more accurate than those taken with Apex DSP®, regardless of the irrigating solution used (p < 0.05). It was concluded that Elements Diagnostic® and Root ZX® apex locators are able to locate the cementum-dentine junction more precisely than Apex DSP®. The presence of irrigating solutions does not interfere with the performance of the EALs.

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

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

Evaluation of the maxillary premolar roots dissociation using radiographic holders with conventional and digital radiography.

This in vivo study evaluated the dissociation quality of maxillary premolar roots combining variations of vertical and horizontal angulations by using X-ray holders (Rinn -XCP), and made a comparison between two types of intraoral radiography systems - conventional film (Kodak Insight, Rochester, USA) and digital radiography (Kodak RVG 6100, Kodak, Rochester, USA). The study sample was comprised of 20 patients with a total of 20 maxillary premolars that were radiographed, using the paralleling angle technique (GP), with a 20º variation of the horizontal angle (GM) and 25º variation of the horizontal angle combined with 15º vertical angle (GMV). Each image was independently analyzed by two experienced examiners. These examiners assigned a score to the diagnostic capability of root dissociation and the measurement of the distance between the apexes. Statistical data was derived using the Wilcoxon Signed Rank test, Friedman and T test. The means of the measured distances between buccal and lingual root apexes were greater for the GMV, which ranged from 2.3 mm to 3.3 mm. A statistically significant difference was found between GM and GMV when compared to GP with p < 0.01. An established best diagnostic dissociation roots image was found in the GMV. These results support the use of the anterior X-ray holders which offer a better combined deviation (GMV) to dissociate maxillary premolar roots in both radiography systems.

Evaluation of the maxillary premolar roots dissociation using radiographic holders with conventional and digital radiography

This in vivo study evaluated the dissociation quality of maxillary premolar roots combining variations of vertical and horizontal angulations by using X-ray holders (Rinn -XCP), and made a comparison between two types of intraoral radiography systems - conventional film (Kodak Insight, Rochester, USA) and digital radiography (Kodak RVG 6100, Kodak, Rochester, USA). The study sample was comprised of 20 patients with a total of 20 maxillary premolars that were radiographed, using the paralleling angle technique (GP), with a 20º variation of the horizontal angle (GM) and 25º variation of the horizontal angle combined with 15º vertical angle (GMV). Each image was independently analyzed by two experienced examiners. These examiners assigned a score to the diagnostic capability of root dissociation and the measurement of the distance between the apexes. Statistical data was derived using the Wilcoxon Signed Rank test, Friedman and T test. The means of the measured distances between buccal and lingual root apexes were greater for the GMV, which ranged from 2.3 mm to 3.3 mm. A statistically significant difference was found between GM and GMV when compared to GP with p < 0.01. An established best diagnostic dissociation roots image was found in the GMV. These results support the use of the anterior X-ray holders which offer a better combined deviation (GMV) to dissociate maxillary premolar roots in both radiography systems.

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

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

Analysis of apical root transportation associated with ProTaper Universal F3 and F4 instruments by using digital subtraction radiography.

INTRODUCTION: The aim of this study was to assess the occurrence of apical root transportation after the use of ProTaper Universal rotary files sizes 3 (F3) and 4 (F4). METHODS: Instruments were worked to the apex of the original canal, always by the same operator. Digital subtraction radiography images were produced in buccolingual and mesiodistal projections. A total of 25 radiographs were taken from root canals of human maxillary first molars with curvatures varying from 23-31 degrees. Quantitative data were analyzed by intraclass correlation coefficient and Wilcoxon nonparametric test (P = .05). RESULTS: Buccolingual images revealed a significantly higher degree of apical transportation associated with F4 instruments when compared with F3 instruments in relation to the original canal (Wilcoxon test, P = .007). No significant difference was observed in mesiodistal images (P = .492). CONCLUSIONS: F3 instruments should be used with care in curved canals, and F4 instruments should be avoided in apical third preparation of curved canals.

Morphological assessment of dentine and cementum following apicectomy with Zekrya burs and Er:YAG laser associated with direct and indirect Nd:YAG laser irradiation.

OBJECTIVES: This study aimed to assess the apical surface morphology of maxillary central incisors resected 3.0 mm from the tooth apex using Zekrya burs or Er:YAG laser, with or without subsequent direct Nd:YAG laser irradiation (apical and buccal surfaces) and indirect irradiation (palatal surface). STUDY DESIGN: Forty maxillary central incisors were instrumented and obturated. The roots were divided into 4 groups according to the root resection method (Zekrya bur or Er:YAG laser - 1.8 W, 450 mJ, 4 Hz, 113 J/cm(2)) and further surface treatment (none or Nd:YAG laser - 2.0 W, 100 mJ, 20 Hz, 124 J/cm(2)). The teeth were prepared for SEM analysis. Scores ranging from 1 to 4 were attributed to cut quality and morphological changes. The data were analyzed by the Kruskal-Wallis test and by Dunn's test. RESULTS: SEM images showed irregular surfaces on the apical portions resected with Zekrya burs, with smear layer and grooves in the resected dentine and slight gutta-percha displacement and plasticization. On the other hand, apicectomies carried out with Er:YAG laser showed morphological changes compatible with ablated dentine, with rough surfaces and craters. In spite of the presence of plasticized gutta-percha, with the presence of bubbles, an irregular adaptation of the filling material to the root walls was also observed. Direct Nd:YAG laser irradiation of the apical and buccal surfaces of the resected roots resulted in areas of resolidification and fusion in the dentine and cementum, with a vitrified aspect; indirect Nd:YAG laser irradiation of the palatal surfaces yielded a lower number of changes in the cementum, with irregular resolidification areas. CONCLUSIONS: There were no differences in terms of cut quality between the use of burs and Er:YAG laser or between the 2 surfaces (apical and buccal) treated with Nd:YAG laser with direct irradiation. However, morphological changes were significantly less frequent on surfaces submitted to indirect irradiation (palatal) when compared with those directly irradiated.

Estudo comparativo da reação tecidual conjuntiva de ratos, frente a três cimentos endodônticos resinosos / Comparative study of rat's connective tissue reaction, against three endodontic resin cements

Objetivo - Este estudo avaliou in vivo a biocompatibilidade dos cimentos AH Plus, Acroseal e EndoREZ, após a implantação em tecido subcutâneo de 16 ratos Wistar. Métodos - Os cimentos foram colocados no interior de tubos de polietileno e implantados em locais específicos no subcutâneo do dorso dos animais. Os blocos de tecidos foram removidos após 24 horas, 72 horas, 7 dias e 21 dias, processados histologicamente e analisados através da observação microscópica óptica. Resultados - Os resultados indicaram que todos os cimentos induziram reações inflamatórias discretas, que diminuíram ao longo do experimento. Conclusões - O cimento Acroseal apresentou o melhor comportamento biológico, seguido pelo AH Plus e EndoREZ.

Objective - The purpose of this study was evaluate in vivo the biocompatibility of the cements AH Plus, Acroseal and EndoREZ, after implantation in connective tissue of sixteen Wistar rats. Methods - The cements were put in the polyethilene tubs and implanted in specific areas in animal's dorsal subcutaneous. The block of tissues was removed after 24 hours, 72 hours, 7 days and 21 days, histological processes was conducted and analyzed under optical microscopic observation. Results - The results indicated that all cements induced mild inflammatory reaction, that decreased with the experiment time. Conclusions - The Acroseal cement showed the best biological reaction, followed by AH Plus and EndoREZ.

Apical leakage of three resin-based endodontic sealers after 810-nm-diode laser irradiation.

OBJECTIVE: To evaluate the influence of 810-nm-diode laser irradiation, applied before root canal filling, on apical sealing ability of three different resin-based sealers (AH Plus, EndoRez, and RealSeal). BACKGROUND: Lasers have been widely used in endodontics. The dentin wall changes caused by laser irradiation could improve the sealing ability of endodontic cements. METHODS: Sixty single-rooted human teeth were divided into six groups, according to the endodontic sealer used and previous 810-nm-diode laser irradiation. The protocol for laser irradiation was 2.5 W in a continuous wave, in scanning mode, with four irradiations per tooth. After sample preparation, they were analyzed according to apical leakage with silver nitrate impregnation. RESULTS: The RealSeal sealer achieved minimum leakage rates (1.24 mm), with significant differences at the 1% level (Tukey's test, p<0.01) from AH Plus (1.84 mm) in nonirradiated groups. When the laser was used, there were also significant differences at the 5% level (p<0.05) between irradiated groups (1.31 and 1.78 mm, respectively). CONCLUSION: The 810-nm-diode laser irradiation did not promote significant differences in apical leakage.

Comparação in vitro do tratamento das perfurações de furca com agregado de trióxido mineral e amálgama de prata / In vitro study comparison of furcal perforations treatments using mineral trioxide aggregate and silver amalgam

Introdução - A perfuração na região de furca é considerada um dos mais sérios fatores para o fracasso do tratamento endodôntico. Baseado nisso, o objetivo do estudo foi comparar a capacidade seladora do amálgama de prata e do MTA em perfurações de furca. Materiais e Métodos - Foram utilizados 24 molares superiores e inferiores, que após cirurgia de acesso, tiveram uma perfuração na região da furca feita com broca carbide nº 3 em alta rotação. As paredes externas foram impermeabilizadas com cianoacrilato de etila e os espécimes foram divididos em dois grupos experimentais, com 10 elementos cada, onde G1 foi vedado com MTA e G2 com amálgama de prata. Os dentes foram, então, imersos em corante azul de metileno por 24 horas e, posteriormente, seccionados longitudinalmente para mensuração das infiltrações, classificadas em 3 níveis. Resultados - Sete elementos do Grupo 1 não apresentaram infiltração de corante e 3 tiveram pequena infiltração. Já no Grupo 2, apenas 2 dentes não demonstraram infiltração enquanto que o restante ficou igualmente dividido entre infiltração pequena e severa. O teste de Kruskal-Wallis revelou diferenças significantes entre os grupos experimentais. Conclusão - É lícito concluir que o MTA apresenta capacidade superior para o vedamento das perfurações de furca do que o amálgama de prata.

Introduction - Furcal perforation is considered one of the most serious factors for the endodontic treatment failure. Based on this, the aim of this study was to compare the marginal sealing promoted by the amalgam and MTA in the furcal perforations. Materials and Methods - In present study were used 24 upper and lower molars were used. After the endodontic access, a perforation in the furcal area was made with a carbide drill #3. The external teeth walls received two layers of ethyl cyanoacrylate and then, the specimens were divided in two experimental groups, with 10 teeth each, where G1 was sealed with MTA and G2 with amalgam. The teeth were immersed in methylene blue dye for 24 hours and after that, split longitudinally to measure the leakage index, classified in three levels. Results - Seven samples of Group 1 did not show dye leakage and two showed small leakeage. In Group 2, only 2 specimens did not have any sign of dye leakage whereas the rest of them was divided in small and severe leakage. Kruskal-Wallis test showed significant differences between experimental groups. Conclusion - It was conclude that MTA promoted a better seal for furcal perforations than the amalgam.

Nd:YAG laser improves biocompatibility of human dental root surfaces.

OBJECTIVE: Our goal was to compare the in vivo biocompatibility of dental root surfaces submitted to four different treatments after tooth avulsion followed by implantation into rat subcutaneous tissue. BACKGROUND DATA: Dental root surface preparation prior to replanting teeth remains a challenge for endodontists. Root surface changes made by Nd:YAG irradiation could be an alternative preparation. METHODS: Forty-eight freshly extracted human dental roots were randomly divided into four treatment groups prior to implantation into rat subcutaneous tissue: G1, dry root, left in the environment up to 3 h; G2, the same treatment as G1, followed by a soaking treatment in a 2.4% sodium fluoride solution (pH 5.5); G3, root soaked in physiologic saline after avulsion for 72 h; G4, the same treatment as G1, followed by Nd:YAG laser irradiation (2.0 W, 20 Hz, 100 mJ, and 124.34 J/cm(2)). The animals were sacrificed 1, 7, and 45 d later. Histological and scanning electron microscopy analyses were done. RESULTS: All dental roots were involved and in intimate contact with connective tissue capsules of variable thicknesses. Differences were observed in the degree of inflammation and in connective tissue maturation. In G3 the inflammatory infiltrate was maintained for 45 d, whereas the Nd:YAG laser irradiation (G4) led to milder responses. The overall aspects of the root surfaces were similar, except by the irradiated roots, where fusion and resolidification of the root surface covering the dentinal tubules were observed. CONCLUSION: Nd:YAG laser irradiation improves the biocompatibility of dental root and thus could be an alternative treatment of dental root prior to replantation.

Comparison of different irrigants on calcium hydroxide medication removal: microscopic cleanliness evaluation.

Calcium hydroxide dressing residuals can compromise endodontic sealing. This study evaluated the cleaning efficacy of different endodontic irrigants in removing calcium hydroxide by SEM image analysis. Fifty-four single-rooted mandibular premolars were instrumented to a master apical file #60 and dressed with calcium hydroxide. After 36 hours, the teeth were reopened and Ca(OH)(2) medication was removed by 5 different experimental groups: 0.5% NaOCl (G1), EDTA-C (G2), citric acid (G3), EDTA-T (G4), and re-instrumentation with MAF using NaOCl and lubrificant, followed by EDTA-T (G5). The roots were split in the buccal-lingual direction and prepared for SEM analysis in cervical, middle, and apical thirds (9, 6, and 3mm from the apex). Five blinded examiners evaluated the wall cleanliness using a scale from 1 to 5. Statistical analysis was performed using Kruskal-Wallis at 5% level of significance. Group G5 had the best results in all thirds, with significant statistical differences compared to all other groups in the middle and coronal third, and to G1 in the apical third. On the other hand, G1, only flushed with NaOCl, had the worst results, with statistical differences in all thirds compared to the other groups. The best cleanliness was achieved by G4 and G5 groups. The recapitulation of MAF in combination with irrigants improved the removal of calcium hydroxide medication better than an irrigant flush alone.

Morphologic changes and removal of debris on apical dentin surfaces after Nd:YAG laser and diode laser irradiation.

OBJECTIVE: To verify the effects of laser energy on intracanal dentin surfaces, by analyzing the morphologic changes and removal of debris in the apical third of 30 extracted human teeth, prepared and irradiated with the Nd:YAG laser and diode laser. BACKGROUND DATA: Lasers have been widely used in endodontics. The morphologic changes in dentin walls caused by Nd:YAG and diode laser irradiation could improve apical seals and cleanliness. MATERIALS AND METHODS: The protocol used for Nd:YAG laser irradiation was 1.5 W, 100 mJ, and 15 Hz, in pulsed mode, and for diode laser was 2.5 W in continuous mode. Each specimen was irradiated four times at a speed of 2 mm/sec with a 20-sec interval between applications. Five calibrated examiners scored the morphologic changes and debris removal on a 4-point scale. RESULTS: In analyzing the scores, there were no statistically significant differences between the two types of laser for either parameter, according to Kruskal-Wallis testing at p = 0.05. The SEM images showed fusion and resolidification of the dentin surface, with partial removal of debris on the specimens irradiated with the Nd:YAG laser and the diode laser, compared with controls. CONCLUSION: Both lasers promote morphologic changes and debris removal. These alterations of the dentin surface appeared to be more evident in the Nd:YAG laser group, but the diode laser group showed more uniform changes.

Periodontite apical assintomática: relato de caso clínico / Assymptomatic apical periodontitis: clinical report

O presente trabalho relata a história clínica de uma paciente de 37 anos de idade, que se apresentou a Universidade Paulista (UNIP), queixando-se de uma "espinha no queixo que não sarava". O exame radiográfico mostrou uma extensa área radiolúcida envolvendo os dentes anteriores, que através do mapeamento com cone de guta-percha e radiografia, detectou-se que a espinha no queixo era uma fístula extra-oral associada ao dente 41. O tratamento proposto foi o endodôntico com curativos à base de hidróxido de cálcio. Durante o tratamento deste dente, a paciente se queixou de uma "bolinha" na região lingual. Com novo mapeamento constatou-se outra fístula, intra-oral, correspondente a uma lesão periapical no dente 34. Foi proposto o mesmo procedimento com curativos à base de hidróxido de cálcio. Observou-se o desaparecimento das duas fístulas. O tratamento endodôntico à base de curativos de hidróxido de cálcio foi eficaz e a proservação foi necessária para acompanhar a reparação neste tipo de patologia.

The present study relates a clinical history of a 37 years old patient that presented to the University Paulista (UNIP) reporting "a pimple in her chin that never dried". A radiographic exam showed a large radiolucense area involving the anterior teeth that traced with a gutapercha point showed that it was an extraoral fistula, concerning the 41 tooth. The treatment proposed was the endodontic with intracanal medication of calcium hydroxide. During the treatment the patient reported a pimple in the lingual region. With a new traced radiography, it was constacted another fistula, intraoral, corresponding to a periapical lesion in the 34 tooth. It was proposed the same treatment with calcium hydroxide. It was observed the cure of the both fistulas. The endodontic treatment with intracanal medication of calcium hydroxide was effective and it was necessary to accompany the cure in this patology.

Influence of Nd:YAG and diode laser irradiation on apical sealing when associated with AH plus and EndoREZ endodontic cements.

OBJECTIVE: This study aims to evaluate the influence of Nd:YAG and diode laser irradiation on apical sealing when applied before root canal filling done with two different resin-based cements (AH Plus and EndoREZ). BACKGROUND DATA: Lasers have been widely used in endodontics. The morphologic changes in dentin walls caused by Nd:YAG and diode laser irradiation could improve sealing ability of endodontic cements. METHODS: Eighty canine teeth were analyzed by apical leakage of methylene blue dye and by scanning electron microscope (SEM) images of the filling's adaptation to the apical third dentin walls. The laser irradiation parameters for the Nd:YAG laser were 100 mJ, 15 Hz, and 1.5 W, and for the diode laser was 2.5 W (continuous mode). RESULTS: The apical leakage results showed statistically significant differences at the 5% level of significance (Tukey's test, p < 0.05) among the different root canal wall treatments, independently of the root canal filling cement used. The cements also showed significant differences between them on the lased groups. The SEM analysis revealed better filling adaptation for AH Plus and the Nd:YAG laser group, confirming the microleakage results. CONCLUSION: We concluded that the combination of the Nd:YAG laser and AH Plus showed the best results.

Study of the areas and thicknesses of mesiobucal root canals prepared by three endodontic techniques.

The purpose of this study was to compare, in vitro, by means of computerized analysis of digital radiographic images, the anatomic alterations produced in the mandibular molar tooth dentinal walls of mesiobucal canals with severe curvature by three different endodontic techniques: Progressive Preparation, Staged and Serial Preparation. A selection was made of 45 extracted, human, mandibular molars, with root curvatures greater than 25 degrees. They were divided into three groups for every technique studied, which were then sub-divided into three sub-groups in accordance with the position of the curvature along the root: cervical, median or apical. After access surgery and tooth length determination, the canals were filled with 100% Barium Sulphate radiological contrast and the teeth were then radiographed with a direct digital radiography system, using a special apparatus capable of keeping the samples in the same spatial position during the different radiographic takes. After the above-mentioned endodontic techniques had been performed, the teeth were again filled with Barium sulphate and were also radiographed under the same previously mentioned conditions. The pre- and post-operative digital images were then analyzed in two computerized programs, AutoCAD 2004 and CorelDraw 10, to assess, respectively, the areas and the horizontal alterations which occurred in the internal and external walls of the root canals. The results indicated that although no significant differences among the techniques were shown in the statistical analysis, in a descriptive analysis the Progressive Preparation technique was shown to be more regular, uniform and effective.

Composição e avaliação de aplicativo hipermídia como recurso educacional na graduação de Endodontia / Composition and evaluation of applicatory hypermedia as educational resource in Endodontics graduation

Introdução - O computador tornou-se uma necessidade no mundo em que vivemos, e o ensino representado pela universidade, na missão de preparar o aluno para a carreira profissional, sente a responsabilidade de não fechar os olhos para essa realidade. Atualmente, a presença da informática na didática de ensino representa novas configurações e metodologias para a condução do processo de ensino e aprendizado, bem como a difusão das diferentes formas de conhecimentos. No desenvolvimento da computação, a hipermídia retrata com fidelidade, som, texto, imagem e animação. Aplicados em sala de aula esses recursos caracterizam interatividade e interferência na seqüência de apresentações. Frente a esta nova temática, o presente estudo teve como objetivo a introdução de um CD-ROM como coadjuvante no estudo da Endodontia, especificamente a técnica endodôntica, a fim de verificar os benefícios da hipermídia dentro do contexto educacional. Material e Métodos - A hipermídia em formato de CD-ROM foi desenvolvida a partir da coleta de todo material endodôntico, bem como o tratamento das mídias com auxílio de softwares específicos. Possibilitando assim, a realização de um arquivo auto-executável quando inserido no drive do computador, permitindo uma navegação da hipermídia de forma não linear pelo usuário. Resultados- A avaliação do CD-ROM foi realizada com alunos da disciplina de Endodontia onde foi verificada a sua aplicabilidade. Conclusão - Os resultados estatísticos mostraram que o uso da hipermídia pode ser uma ferramenta motivadora no ensino da Endodontia

Location and angulation of curvatures of mesiobucal canals of mandibular molars debrided by three endodontic techniques.

The aim of this study was to assess the correlation between the degree of angulation and the position of root curvatures and their influence on the comparative results between the performances of the Progressive, Staged and Serial Preparation Techniques. The mesiobucal canals of 70 extracted mandibular molars were filled with a radiological contrast of 100% Barium sulphate and radiographed with a direct digital radiographic system, in an apparatus that guarantees that the samples remain in the same spatial position at all times. The images were then analyzed in the Coreldraw 10 program (MicroSafe, RJ, Brasil) in accordance with two criteria: the methods of Berbert, Nishiyama(1) (1994) and Schneider11 (1971) to determine the position and the angle of the root curvatures, respectively. Initially, the possibility of correlation between these two variables was studied. The teeth were then selected according to angulation (greater than 25 degrees) and position of root curvatures (cervical, median and apical) in order to perform the endodontic techniques. After preparation, the samples were radiographed again and the images were superimposed in order to compare the pre- and post-operative areas. The difference between them showed the percentage of widening for each technique. The results showed that there was no correlation between the angulations and the root curvature positions, and that the different positions did not interfere in the performance of the techniques. The Progressive Preparation technique produced the highest widening values for all the groups, irrespective of the root curvature position.