Influência do retratamento na formação de microtrincas dentinárias em molares inferiores obturados com o cimento biocerâmico total fill: análise por micro-ct / Influence of retreatment on the formation of dentinal microcracks in lower molars filled with total bioceramic cement fill: micro-ct analysis

Objetivo Este estudo teve como objetivo avaliar a incidência de microtrincas dentinárias após a remoção do material obturador utilizando o cimento biocerâmico TotalFill BC através de análises de microtomografia computadorizada (micro-CT). Metodologia Vinte raízes mesiais de molares mandibulares foram obturadas com guta percha e cimento Total Fill BC e em seguida o material obturador foi removido. As amostras foram escaneadas por micro-CT antes do preparo químico-mecânico, após a obturação e posteriormente a remoção do material obturador. As imagens transversais das raízes mesiais obtidas após a obturação foram analisadas e comparadas com as imagens após a remoção do material obturador, utilizando o programa Image J. Resultados Dos 24.444 cortes transversais analisados, 5,67% apresentaram algum defeito de dentina, sendo que nas imagens iniciais foram encontradas 0,51%, nas imagens pós obturação 2,58%, e nas imagens obtidas após a desobstrução 2,58%. Nas análises comparando as imagens iniciais e pós-obturação foram observados 1,65% dos cortes com novas microtrincas. Todos os defeitos dentinários identificados na análise das imagens obtidas após a remoção do material obturador já estavam presentes nas imagens correspondentes obtidas após a obturação. Desta forma, nenhuma nova microfissura foi observada após remoção do material obturador. Conclusão O estudo não visualizou a produção de novas microtrincas dentinárias durante a fase de desobstrução do retratamento endodôntico. (AU)

Aim The present study aimed to evaluate the frequency of dentinal micro-cracks after removal of the filling material using the TotalFill BC bioceramic-based root canal sealer through microcomputed tomography (micro-CT) analyzes. Methodology Twenty mesial roots of mandibular molars were filled with gutta-percha and TotalFill BC sealer and then the filling material was removed. The specimens were scanned by micro-CT, before instrumentation, after filling and after removal of the filling material. Subsequently, the transversal images of the mesial roots obtained after filling were analyzed and compared with that obtained after removal of the filling material, using the program Image J. Results Among the 24.444 cross sections analyzed, 5,67% presented some type of defect, with 0.51% in the initial images, 2.58% in the post-filling images and 2.58% in the final images. In the analysis comparing the initial images with the post-filling, 1,65% of the sections presented new microcracks. All the dentin defects identified in the analysis of the images obtained after the removal of the filling material were already present in the corresponding images obtained after the filling. Therefore, no new microcrack was observed after removal of the filling material. Conclusion The study did not visualize the production of new dentin microcracks during the removal of filling material in the endodontic retreatment. (AU)

Diameter and Taper Variability of Single-file Instrumentation Systems and Their Corresponding Gutta-percha Cones.

INTRODUCTION: Manufacturers offer single-file instrumentation systems with matching gutta-percha (GP) cones to simplify root canal preparation and obturation. The purpose of this study was to determine whether file diameters and tapers match with corresponding cone diameters and tapers (precision) as well as industry standards (accuracy). METHODS: Twenty files and corresponding GP cones from each size of F360 (#25, #35, #45, #55 with .04 taper) and Reciproc (#25, #40, #50 with variable tapers) instruments were examined by using optical microscopy (×32) to determine their diameter and taper. Precision was evaluated by using one-way analysis of variance (α = 0.05) with Scheffé post hoc tests and t tests with Bonferroni correction. Accuracy was calculated by subtracting the nominal values from the measured values of all files and GP cones, and mean diameter and taper differences were compared by using one-way analysis of variance (α = 0.05) and Scheffé post hoc test for pairwise comparison. RESULTS: For F360, the majority of file and cone diameters were within the tolerance levels, but most of the file diameters were significantly larger than GP cone diameters (P < .05), but the majority of all measured values were within the tolerance levels. For Reciproc, file and cone diameters at D1 and D3 mostly approached the nominal values. At the coronal end, file diameters #25 and #50 were significantly smaller than cone diameters (P < .05). For both instrumentation systems, almost all file and cone tapers matched with the preset tolerance ranges. For Reciproc, significant differences between file and GP cone demonstrated either smaller cone or smaller file diameters and tapers, depending on the size. Most of the measured values were within the acceptable range, but diameters at the coronal end exhibited the highest percent difference from the nominal values. CONCLUSIONS: Despite the call for standardization, variability in diameter and taper dimensions between single-file instrumentation systems and their corresponding GP cones can be expected.

Radiographic Diagnosis of Periapical Status and Quality of Root Canal Fillings in a Saudi Arabian Subpopulation.

PURPOSE: To assess the prevalence of apical periodontitis (AP), as determined by orthopantomograms (OPGs), and its correlation with the quality of root fillings and coronal restorations. MATERIALS AND METHODS: This cross-sectional study evaluated a random sample of 193 patients--112 (58%) females and 81 (42%) males--who presented as new patients at the Division of Endodontics. Digital OPGs were independently examined by two reliability-calibrated endodontists. The total number of teeth present, the location of the root canalfilled teeth, and the presence or absence of AP were recorded for each radiograph. The results were statistically analysed using the chi-square test followed by model building using multiple logistic regression. RESULTS: A total of 324 endodontically treated teeth from the 193 selected radiographs were analysed. The mean number of teeth per patient was 25.5 ± 4.6, with an average of 1.64 root canal treatments per subject. Radiographically detected AP was associated with 190 (58.6%) root canal-treated teeth. The logistic model shows that the quality of endodontic treatment (adjusted odds ratio [ORa] = 1.82; 95% confidence interval [CI]: 1.40-3.17), status of coronal restoration (ORa = 1.77; 95% CI: 1.20-2.61) and the type of material used for coronal restorations (ORa = 1.39; 95% CI: 1.03-1.87) were significantly related to the periapical health of the teeth. CONCLUSIONS: The quality of endodontic treatment, status of coronal restoration and the type of coronal restorative material were found to be the most important factors influencing the health of periradicular tissue.

Quality of obturation achieved by a non-gutta-percha-based root filling system in single-rooted canals.

INTRODUCTION: The present study examined the quality of obturation in root canals filled by an experimental non-gutta-percha-based (NGP) root filling system using warm vertical or cold lateral compaction. The quality of obturation was evaluated by comparing the volumetric percentage of gaps and voids identified from similar canals obturated with gutta-percha and an epoxy resin-based sealer using the same obturation techniques. METHODS: Forty single-rooted premolars with oval-shaped canals were cleaned, shaped, and obturated with 1 of the 4 material/obturation technique combinations (n = 10). Filled canals were scanned with micro-computed tomographic imaging. Reconstructed images were analyzed for the volumetric percentage of gaps and voids at 3 canal levels (0-4, 4-8, and 8-12 mm from the working length). Roots were sectioned at the 4-mm, 8-mm, and 12-mm levels. Scanning electron microscopic images of negative replicas of root sections were examined to quantify the circumferential percentage of interfacial gaps and the area percentage of intracanal voids. Data were analyzed with parametric or nonparametric statistical methods. RESULTS: A statistically significant difference was found for the volumetric percentage distribution of gaps and voids for "obturation technique" but not for "material." Significantly higher percentages of gaps and voids were identified in canals obturated with the NGP system using cold lateral compaction. Examination of negative replicas ascribed this difference to a higher area percentage of interfacial gaps rather than more intracanal voids. CONCLUSIONS: Using warm vertical compaction, the NGP system fulfils the objective of 3-dimensional obturation of the canal space in a manner comparable with the results achieved with gutta-percha and a root canal sealer.

Quality of obturation achieved by an endodontic core-carrier system with crosslinked gutta-percha carrier in single-rooted canals.

OBJECTIVES: The present study examined the quality of obturation in root canals obturated by GuttaCore, a gutta-percha-based core-carrier system with a cross-linked thermoset gutta-percha carrier, by comparing the incidence of gaps and voids identified from similar canals obturated by cold lateral compaction or warm vertical compaction. METHODS: Thirty single-rooted premolars with oval-shaped canals were shaped and cleaned, and obturated with one of the three obturation techniques (N=10): GuttaCore, warm vertical compaction or cold lateral compaction. Filled canals were scanned with micro-computed tomography (micro-CT); reconstructed images were analysed for the volumetric percentage of gaps and voids at three canal levels (0-4mm, 4-8mm and 8-12mm from working length). The roots were subsequently sectioned at the 4-mm, 8-mm and 12-mm levels for analyses of the percentage of interfacial gaps, and area percentage of interfacial and intracanal voids, using scanning electron microscopy (SEM) to examine negative replicas of root sections. Data were analysed with parametric or non-parametric statistical methods at α=0.05. RESULTS: Both micro-CT and SEM data indicated that canals obturated with GuttaCore core-carriers had the lowest incidence of interfacial gaps and voids, although the results were not significantly different from canals obturated by warm vertical compaction. Both the GuttaCore and the warm vertical compaction groups, in turn, had significantly lower incidences of gaps and voids than the cold lateral compaction group. CONCLUSIONS: Because of the similarity in obturation quality between GuttaCore and warm vertical compaction, practitioners may find the GuttaCore core-carrier technique a valuable alternative for obturation of oval-shaped canals. CLINICAL SIGNIFICANCE: The quality of obturation achieved by GuttaCore in single-rooted canals is not significantly different from that achieved by warm vertical compaction.

Quality of different gutta-percha techniques when filling experimental internal resorptive cavities: a micro-computed tomography study.

The purpose of this ex vivo study was to determine the quality of root fillings in experimental internal resorptive cavities filled using cold lateral condensation (CLC), vertical condensation and Thermafil techniques. Forty-five extracted maxillary canine teeth were selected. After root canal instrumentation, the roots were sectioned horizontally and experimental internal resorption cavities were prepared. The root sections were re-approximated with a luting agent and randomly assigned to three groups (n = 15) to be filled using CLC, vertical condensation and Thermafil, respectively. Assessment of obturation quality in the internal resorptive cavity was performed using a desktop X-ray micro focus computed tomography scanner, and the percentage of gutta-percha (GP), sealer and voiding was calculated for each specimen. Data were statistically analysed using non-parametric tests, with P < 0.05 denoting a statistically significant difference. Vertical condensation filled 96.25 ± 8.31% of the total artificial cavity, and was superior to CLC (63.20 ± 16.87%) and Thermafil (59.26 ± 18.47%). The mean percentage of voids was 3.75 ± 8.31% in the vertical condensation group, 37.09 ± 17.13% in the CLC group and 41.06 ± 18.60% in the Thermafil group. We conclude that obturation of experimental resorption cavities is significantly better when using vertical condensation than when using other GP-based techniques.

Carrier-based root canal filling materials: a literature review.

A review of the literature on the use of carrier based obturation materials focusing on Thermafil and Resilon based obturator (RealSeal 1) are presented in this article. The review addressed the history, apical leakage, coronal leakage, biocompatibility, sealing ability and clinical success of Thermafil and RealSeal 1. Based on the studies gathered, this review concluded that both treatment techniques (Thermafil and RealSeal 1) did not provide excellent apical sealing ability. More research should be done to try to overcome their main drawback, its sealing ability.

The association between complete absence of post-treatment periapical lesion and quality of root canal filling.

AIM: The technical quality of a root canal treatment is clinically judged by the apical extension and homogeneity of the filling material imaged by periapical radiographs (PA). The aim of this experiment was to evaluate the association between the technical quality of the root canal filling and treatment outcome. MATERIALS AND METHODS: In 234 teeth (268 roots) that underwent root-canal treatment, the quality of the root canal filling as well as the outcome of the treatment were assessed with both PA and cone-beam computed tomography (CBCT) 2 years after treatment. Satisfactory root filling on PA was defined as 0-2 mm within the radiographic apex without voids; on CBCT scans, the apical end of the canal replaced the radiographic apex. The outcome predictors were analyzed using multivariate logistic regression. RESULTS: At recall, periapical radiolucent areas were absent in 198 (74%) roots on PA and 164 (61%) roots on CBCT scans. The presence of preoperative periapical radiolucency and the quality of root filling and coronal restoration were identified by both PA and CBCT as outcome predictors (p < 0.01). Complete absence of post-treatment periapical radiolucency was observed in CBCT scans in 81% and 49% of satisfactory and unsatisfactory root fillings, respectively, as compared to 87% and 61% revealed by PA. CONCLUSION: Satisfactory root fillings were associated with a favorable outcome, confirmed by both PA and CBCT. CLINICAL RELEVANCE: The outcome of root canal treatment is improved once the filling is 0-2 mm from the apex, and no voids could be detected. Technical skills and performance of root canal filling procedures should be emphasized, and suitable methods should be developed in order to achieve more compacted filling materials without voids and at the correct length.

Tip diameter of 0.04 and 0.06 tapered gutta-percha points from different commercial brands / Diâmetro da ponta (d0) de cones de guta-percha de conicidades 0, 04 e 0, 06 de diferentes marcas comerciais

Objective: The aim of this study was to determine the correlation between the diameter D0 of guttapercha points from three different commercial brands (Tanari Man, Cone Tech and Dentsply) and their original respective values. Materials and methods: A high precision micrometer was used by a single calibrated operator to evaluate if the gutta-percha points are in aggrement with the n. 57 ANSI/ADA specification. Results: For the 0.04 tapered points, Cone Tech showed lower percentage of inadequate points (52%), followed by Dentsply (56%) and Tanari (80%). For the 0.06 tapered points, Cone Tech showed lower percentage of inadequate points (50%), followed by manufacturers Dentsply (53%) and Tanari (81%). Conclusions: It can be concluded that there is no standardization in the diameter D0 of the gutta-percha points of different commercial brands.

Objetivo: O objetivo deste estudo foi determinar a correlação entre o diâmetro D0 dos cones de guta-percha detrês diferentes marcas comerciais (Tanari Man, Cone Tech e Dentsply) com seus respectivos valores originais. Materiais e métodos: Um micrômetro de alta precisão foi utilizado por um único operador devidamente calibradopara avaliar se os cones de guta-percha estavam de acordo com a norma n. 57 da ANSI/ADA. Resultados:Para a conicidade 0.04, Cone Tech apresentou menor percentual de cones inadequados (52%), seguido deDentsply (56%) e Tanari (80%). Para a conicidade 0.06, Cone Tech apresentou menor percentual de conesinadequados (50%), seguido de Dentsply (53%) e Tanari (81%). Conclusões: Pôde-se concluir que não há padronizaçãono diâmetro D0 dos cones de guta-percha das diferentes marcas comerciais.

[Comparison of guttapercha points of different brands]. / Különbözô gyártmányú guttaperchacsúcsok összehasonlító vizsgálata.

Many new devices and instruments have been developed in the field of endodontics, however, even today guttapercha is the most commonly used root canal filling material and lateral condensation is still widely the technique of choice. It is crucial that the guttapercha point should not bend away during insertion into the root canal, and that the size of the guttapercha point is in accordance with the size-coding marked on the container. However, there is no data on the difference between the dimensional accuracy and the rigidity of guttapercha points produced by various manufacturers. The aim of the authors' study was to compare guttapercha points of different brands (ANTEOS, DENTSPLY, DIADENT, EXPORDENT, FKG, META, ROEKO, ROSA BECHT, SURE ENDO). The rigidity of guttapercha points (n = 10 in each group) and the dimensional accuracy has been measured (n = 10 in each group) with an instrument developed for this purpose. Statistical analysis has been performed by ANOVA, level of significance was (p < 0.05). In the group FKG significant (p < 0.05) higher forces were necessary to bend guttapercha points. No other significant difference has been shown between the investigated groups (p > 0.05). In the dimensional accuracy there were significant differences (p < 0.05). The least deviation from the assigned dimension has been found in the ROSABECHT group, and the highest in the FKG group. In the dimensional accuracy the least standard error has been found in ROSABECHT group, and the highest in EXPORDENT group. The most extreme deviations have been shown in META and DENTSPLY group. The results of the present study show that guttapercha points frequently deviate from the marked dimension: a guttapercha point from the ISO 25 container may even reach the size of an ISO 30 guttapercha. This has to be taken into account during root canal obturation.

In vitro antimicrobial activity of different gutta-percha points and calcium hydroxide pastes.

The aim of this study was to evaluate the antimicrobial activity of different trademarks and compositions of gutta-percha points and calcium hydroxide pastes used in endodontic therapy. The evaluated material consisted of gutta-percha points containing calcium hydroxide (Roeko), gutta-percha points containing chlorhexidine (Roeko), two conventional gutta-percha points (Endo Points and Roeko) and two calcium hydroxide pastes (Calen and Calen/PMCC). Antimicrobial tests included five species of microorganisms: Escherichia coli (ATCC10538), Staphylococcus epidermidis (ATCC12228), Staphylococcus aureus (ATCC6538), Pseudomonas aeruginosa (ATCC27853), and Micrococcus luteus (ATCC9341). The Agar diffusion method was employed. The plates were kept at room temperature for 2 h for prediffusion and then incubated at 37 degrees C for 24 h. The triphenyltetrazolium chloride gel was added for optimization and the zones of inhibition were measured. Statistical evaluation was carried out using analysis of variance and Tukey Test. The obtained results showed that all microbial species used in the study were inhibited by the gutta-percha points containing chlorhexidine and by the calcium hydroxide pastes (Calen and Calen/PMCC), with similar results (p > 0.05). No antimicrobial activity was observed for the other groups. It was concluded that the gutta-percha points containing chlorhexidine presented antimicrobial activity, whereas the gutta-percha points containing calcium hydroxide did not.

In vitro antimicrobial activity of different gutta-percha points and calcium hydroxide pastes

The aim of this study was to evaluate the antimicrobial activity of different trademarks and compositions of gutta-percha points and calcium hydroxide pastes used in endodontic therapy. The evaluated material consisted of gutta-percha points containing calcium hydroxide (RoekoTM), gutta-percha points containing chlorhexidine (RoekoTM), two convencional gutta-percha points (Endo PointsTM and RoekoTM) and two calcium hydroxide pastes (CalenTM and Calen/PMCC TM). Antimicrobial tests included five species of microorganisms: Escherichia coli (ATCC10538), Staphylococcus epidermidis (ATCC12228), Staphylococcus aureus (ATCC6538), Pseudomonas aeruginosa (ATCC27853), and Micrococcus luteus (ATCC9341). The Agar difusion method was employed. The plates were kept at room temperature for 2 h for prediffusion and then incubated at 37°C for 24 h. The triphenyltetrazolium chloride gel was added for optimization and the zones of inhibition were measured. Statistical evaluation was carried out using analysis of variance and Tukey Test. The obtained results showed that all microbial species used in the study were inhibited by the gutta-percha points containing chlorhexidine and by the calcium hydroxide pastes (CalenTM and Calen/PMCC TM), with similar results (p > 0.05). No antimicrobial activity was observed for the other groups. It was concluded that the gutta-percha points containing chlorhexidine presented antimicrobial activity, whereas the gutta-percha points containing calcium hydroxide did not.

O objetivo deste estudo foi a avaliação da atividade antimicrobiana de diferentes marcas e composições de cones de guta-percha e pastas à base de hidróxido de cálcio utilizados em endodontia. Os materiais avaliados foram: cones de guta-percha contendo hidróxido de cálcio (RoekoTM), cones de guta-percha contendo clorexidina (RoekoTM), duas marcas de cones de guta-percha (Endo PointsTM e RoekoTM) e duas pastas à base de hidróxido de cálcio (CalenTM e Calen/PMCC TM). Os testes antimicrobianos incluíram 5 espécies de microrganismos: Escherichia coli (ATCC10538), Staphylococcus epidermidis (ATCC12228), Staphylococcus aureus (ATCC6538), Pseudomonas aeruginosa (ATCC27853) e Micrococcus luteus (ATCC9341). O método empregado foi o de difusão em Agar. As placas foram mantidas em temperatura ambiente por 2 horas para pré-difusão e então incubadas a 37°C por 24 horas. O gel de cloreto de trifeniltetrazólio foi acrescentado para otimização e as zonas de inibição foram medidas. A análise estatística foi realizada pela análise de variância e pelo teste de Tukey. Os resultados obtidos demonstraram que todas as espécies microbianas usadas foram inibidas pelos cones de guta-percha com clorexidina e pelas pastas à base de hidróxido de cálcio (CalenTM e Calen/PMCC TM), com resultados similares entre os materiais (p > 0.05). Nenhuma atividade antimicrobiana foi observada para os demais grupos. Concluiu-se que os cones de guta-percha com clorexidina apresentaram atividade antimicrobiana, enquanto os cones com hidróxido de cálcio não demonstraram esta propriedade.

Effect of diode laser irradiation on the apical sealing of MTA retrofillings.

Apical sealing is essential for the success of paraendodontic surgery, so any procedure that may favor an adequate sealing of the apical remainder should be performed. The purpose of this study was to evaluate the influence of diode laser irradiation on the apical sealing of root-end cavities with MTA retrofillings. Root canals in twenty extracted human teeth were shaped with K-files and filled with gutta-percha. The apexes were cut off and root-end preparations were performed. The roots were divided randomly in 2 groups. Group 1 (ten specimens) was retrofilled with MTA. Group 2 was irradiated with diode laser, with 1 W for 20 seconds, on the apical surface and root end cavity before retrofilling with MTA. The specimens had their external surfaces impermeabilized with cyanoacrylate, except for the apical surface, and were then immersed in 1% rhodamine B dye for 72 h and placed in plaster stone. After that, the specimens were submitted to longitudinal abrasion until half of the root remained. The linear dye leakage was observed in these mid-roots between the root canal wall and retrofilling. The linear dye leakage was measured with Image Lab software, and the results were statistically analyzed with Student's t test. There were no statistically significant differences between the two groups (p > 0.05). The diode laser irradiation did not improve the apical sealing of MTA retrofillings under the conditions of this in vitro study.

Variability of the diameter and taper of size #30, 0.04 gutta-percha cones.

The purpose of this investigation was to examine variability of gutta-percha (GP) cone tip diameter (D(0)) and taper among five different brands of #30, 0.04 GP cones (n = 15/brand). Mean percent D(0) difference from the manufacturer's reported (nominal) diameter of Maillefer (-15.42 +/- 7.16%) and Lexicon (-12.76 +/- 4.98%) were significantly different (p < or = 0.05) from Maxima (3.18 +/- 7.06%), Diadent (3.62 +/- 11.37%), and K(3) (7.27 +/- 7.84%), which were not significantly different from each other but exhibited diameters larger than the nominal diameter as indicated by positive values. Mean taper percent difference of Maxima (-3.00 +/- 3.80%) was significantly different (p < or = 0.05) from Lexicon (3.67 +/- 3.64%) and Maillefer (6.67 +/- 3.49%), with comparisons to Diadent (-0.17 +/- 6.37%) and K(3) (1.50 +/- 6.93%) not significantly different (p > 0.05) from each other or any other brand. Based on the evidence, there is significant variability between GP cone brands for both diameter and taper, with Maxima and Diadent, respectively, exhibiting the smallest mean difference from manufacturer's nominal tip diameter and taper. However, the high standard deviation values associated with most of the diameter and taper differences from nominal values also suggest high variability within individual brands.

Effect of diode laser irradiation on the apical sealing of MTA retrofillings / Efeito da irradiação de laser de diodo no selamento apical em retrobturações com MTA

Apical sealing is essential for the success of paraendodontic surgery, so any procedure that may favor an adequate sealing of the apical remainder should be performed. The purpose of this study was to evaluate the influence of diode laser irradiation on the apical sealing of root-end cavities with MTA retrofillings. Root canals in twenty extracted human teeth were shaped with K-files and filled with gutta-percha. The apexes were cut off and root-end preparations were performed. The roots were divided randomly in 2 groups. Group 1 (ten specimens) was retrofilled with MTA. Group 2 was irradiated with diode laser, with 1 W for 20 seconds, on the apical surface and root end cavity before retrofilling with MTA. The specimens had their external surfaces impermeabilized with cyanoacrylate, except for the apical surface, and were then immersed in 1 percent rhodamine B dye for 72 h and placed in plaster stone. After that, the specimens were submitted to longitudinal abrasion until half of the root remained. The linear dye leakage was observed in these mid-roots between the root canal wall and retrofilling. The linear dye leakage was measured with Image Lab software, and the results were statistically analyzed with Student's t test. There were no statistically significant differences between the two groups (p > 0.05). The diode laser irradiation did not improve the apical sealing of MTA retrofillings under the conditions of this in vitro study.

O selamento apical é fundamental para o sucesso da cirurgia parendodôntica. Assim, procedimentos que melhorem o selamento do remanescente apical devem ser utilizados. O objetivo deste estudo foi verificar se a irradiação de laser de diodo poderia aumentar o selamento apical em cavidades retrógradas obturadas com MTA. Foram utilizadas 20 raízes de dentes humanos extraídos que, após preparo com lima tipo K, tiveram seus canais obturados com guta-percha. Os ápices foram cortados e sofreram preparo de cavidades retrógradas. As raízes foram divididas aleatoriamente em 2 grupos. O grupo 1 (dez espécimes) foi retrobturado com MTA, e o grupo 2 sofreu irradiação de laser de diodo na potência de 1 W por 20 s na superfície apical e na cavidade retrógrada antes da obturação com MTA. Os espécimes foram impermeabilizados externamente com cianoacrilato, com exceção da superfície apical, imersos em corante rodamina B a 1 por cento por 72 h, incluídos em gesso e posteriormente desgastados no sentido longitudinal até obter-se metade da raiz. Foi feita a leitura da infiltração linear do corante nessas hemi-raízes, entre a parede do canal radicular e a retroobturação, com auxílio do programa de computação Image Lab. Os resultados foram analisados estatisticamente pelo Teste t de Student. Não houve diferença estatística significante entre os dois grupos (p > 0,05). A irradiação com laser de diodo não proporcionou aumento do selamento apical em retrobturações com MTA sob as condições do presente estudo in vitro.

Analysis of the sealing ability of different obturation techniques in oval-shaped canals: a study using a bacterial leakage model.

The aim of this study was to evaluate the sealing ability of 3 obturation techniques in oval canals using a bacterial leakage model. Seventy mandibular incisors with oval canals were selected after buccolingual and mesiodistal radiographs, and divided into three groups. After instrumentation, the canals were obturated respectively by lateral condensation (G1), warm vertical condensation (G2) and Thermafil (G3). Five root canals were not obturated and served as positive controls; five teeth with intact crowns served as negative controls. All teeth were mounted on a 2 chamber apparatus and then exposed to human saliva. The number of days required for the entire contamination of the root canals was recorded, observing the turbidity of the BHI broth, for a period of 100 days. 84.21% of the samples from the lateral condensation group (G1); 84.21% of the samples from the warm vertical condensation group (G2); and 89.47% of the samples from the Thermafil System group (G3) showed no contamination at the end of the study. No statistical significant difference was found among the three techniques. The quality of the apical seal in the three techniques tested was similar.

Analysis of the sealing ability of different obturation techniques in oval-shaped canals: a study using a bacterial leakage model

O objetivo deste estudo foi avaliar a qualidade do selamento obtido por 3 técnicas de obturação em canais ovais, através de um modelo de infiltração bacteriano. Setenta incisivos inferiores com canais ovais foram selecionados após radiografias bucolinguais e mésio-distais, e divididos em 3 grupos. Após a instrumentação, os dentes foram obturados respectivamente pela condensação lateral (G1), condensação vertical da guta-percha aquecida (G2) e pelo Thermafil (G3). Cinco canais radiculares que não foram obturados serviram como grupo controle positivo, e cinco com as coroas intactas serviram como grupo controle negativo. Todos os dentes foram montados em um aparato de 2 câmaras e expostos à saliva humana. O número de dias necessário à total contaminação do canal radicular foi verificado, através da observação do turvamento do BHI, por um período de 100 dias. Não apresentaram contaminação ao término do estudo 84,21% das amostras do grupo da condensação lateral (G1); 84,21% das amostras do grupo da condensação vertical da guta-percha aquecida (G2); e 89,47% das amostras do grupo do Thermafil. Não houve diferença estatisticamente significativa entre as 3 técnicas. A qualidade do selamento apical nas 3 técnicas testadas foi similar.

An evaluation of the quality of root fillings in mandibular incisors and maxillary and mandibular canines using different methodologies.

OBJECTIVES: To evaluate the quality of root fillings in mandibular incisors and maxillary and mandibular canines using different methodologies of evaluation, namely radiographs, the fluid transport test and the percentage of gutta-percha (PGP), and to determine if a correlation occurs between the results of the different methodologies used. METHODS: One group of mandibular incisors with oval canals (n=20) and one group of maxillary and mandibular canines (n=20) were instrumented and obturated by cold lateral compaction using AH 26 as the sealer. The filled roots were bucco-lingually and mesio-distally radiographed. Using a scoring system, the quality of each root filling was radiographically evaluated, the higher the score the poorer the quality. Fluid transport along the root filling was then measured using a fluid transportation device. Each root was horizontally sectioned 4 and 6mm from the apex. Images of the cross-sections were taken, using a microscope and a digital camera. Images were scanned into a PC as TIFF images. Using a KS 100 Imaging system the canal area and the gutta-percha filled areas were measured. The percentage of gutta-percha filled areas was calculated. RESULTS: Considering the radiographic scores of the two different projections together the score was significantly higher for the mandibular incisors than for the canines (P=0.039). The radiographic score was significantly higher for the mesio-distal radiograph in comparison with the bucco-lingual radiograph (P=0.0001), for the canines as well as the incisors. Using only the bucco-lingual radiograph there was no significant difference between the mandibular incisors and the canines (P=0.992). The mandibular incisors displayed significantly more fluid transport than the canines (P=0.049). A significantly greater percentage of gutta-percha filled areas was found in the cross-sections of canines as compared to the cross-sections of mandibular incisors (P=0.000001). The correlation between the radiographic score of the mesio-distal radiograph and the PGP 4 and 6mm was significant (P=0.013). There was no significant correlation between the FT and the radiograph or the FT and the PGP. CONCLUSIONS: The quality of the root fillings in oval canal-mandibular incisors may be compromised.

Análise quantitativa in vitro da obturação de canais laterais / Quantitative in vitro analysis of the filling of lateral canals

O objetivo deste trabalho foi analisar a capacidade de penetração de guta-percha e cimento nos canais laterais simulados em blocos de resina acrílica realizados com o auxílio de uma microbiota cilíndrica de 0,2 mm de diâmetro. Os canais foram obturados utilizando duas técnicas de obturação: técnica de compactação vertical de Schilder modificada utilizando o Sistema Obtura II e técnica híbrida de Tagger. A técnica utilizando o Sistema Obtura II promoveu maior preechimento de guta-percha nos três terços, enquanto que a técnica híbrida de Tagger promoveu maior preenchimento de cimento nos canais laterais cervicais e mediais

Variability of master gutta-percha cones.

The common technique to hermetically fill prepared root canals involves the use of "standardised" gutta-percha cones that are selected to fit the apical portion of the prepared canal space. These gutta-percha cones are manufactured to conform to a standard size and taper which should correspond to the size and taper of standard root canal instruments. Clinical observation of commercially available gutta-percha cones seemed to indicate that there is wide variation in the diameter and taper of "standardised" gutta-percha cones within the size range 25-35. The present study was undertaken to determine how closely current commercially available gutta-percha cones sizes 25, 30 and 35 conformed to the current ISO standard, and was initiated by the above clinical observation. It was not the purpose of this study to compare the results from different brands or manufacturers, but rather to establish whether commercially available gutta-percha cones collectively conformed to expected standardised sizes. One phial of cones for each of the sizes 25, 30 and 35 of eight different brands was selected for examination. The diameter of each of ten cones for each size from each brand was measured at two points, at 1 mm and at 6 mm from the tip of the cone. The results obtained for each size and each brand were tabulated and compared with ISO 6877:1995 for dental root canal obturating cones. This study demonstrated wide variability for cones from all brands, for all sizes, when individual cones of the same size were compared. While collectively the arithmetic means showed a closer correlation to the ISO Standard, irrespective of the brand size of the cone, or whether the cone was measured at 1 mm or 6 mm, many individual cones showed a great variation from the ideal. The need for less variability is discussed. It is concluded that ISO standard 6877:1995 is inappropriate- and allows for too much variation in the size of "standardised" gutta-percha cones.