Influence of photoactivation on tissue response to different dyes used in photodynamic therapy and laser ablation therapy.

Laser ablation therapy (LA) uses Indocyanine Green dye (ICG) which efficiently absorbs laser energy and the increased temperature results in an instantaneous flame that chars tissue and microbes. Photodynamic therapy (PDT) uses different dyes that are activated by light to kill bacteria. This study evaluated the biocompatibility of the dye Curcumin (CUR), Methylene Blue (MB), and Indocyanine Green (ICG) before and after laser activation (ACT). Polyethylene tubes containing one of the dyes were implanted in the subcutaneous tissue of 32 rats (4 tubes per rat) which were divided into 8 groups: C - control (saline solution); C + ACT (Red Laser 660 nm); CUR; CUR + ACT (480 nm blue LED); MB; MB + ACT (Red Laser 660 nm); ICG; ICG + ACT (810 nm Infrared Laser). After 7 and 30 days (n = 8/time), the rats were euthanized and the tubes with the surrounding tissue were removed and processed for histological analysis of inflammation using H&E stain, and collagen fiber maturation using picrosirius red (PSR). A two-way analysis of variance statistical test was applied (p < 0.05). At 7 days, regardless of laser activation, the CUR group showed a greater inflammatory infiltrate compared to the ICG and control groups, and the MB group had a greater inflammation only in relation to the control (p < 0.05). At 30 days, CUR and MB groups showed a greater inflammatory infiltrate than the control (p < 0.05). ICG group was equal to the control in both periods, regardless of the laser activation (p > 0.05). Laser activation induced the proliferation of collagen immature fibers at 7 days, regardless of the dye (p < 0.05). The CUR group showed a lower percentage of immature and mature fibers at 7 days, compared to ICG and control (p < 0.05) and, at 30 days, compared to control (p < 0.05). Regardless of laser activation, the ICG showed the results of collagen maturation closest to the control (p > 0.05). It was concluded that all dyes are biocompatible and that laser activation did not interfere with biocompatibility. In addition, the maturity of collagen was adequate before and after the laser activation. These results demonstrate that the clinical use of dyes is safe even when activated with a laser.

Clinical Study of Antimicrobial Efficacy of Laser Ablation Therapy with Indocyanine Green in Root Canal Treatment.

INTRODUCTION: Laser ablation (LA) therapy is used as an adjunct to endodontic treatment to improve microbial reduction. However, studies evaluating the impact of LA with indocyanine green (ICG) are scarce. This study aimed to evaluate the antimicrobial efficacy of LA therapy with ICG in root canal treatment. METHODS: Sixty patients with periapical lesions in teeth with a single canal and absence of pain, edema, and previous treatment were selected. Patients were randomly allocated into 3 groups according to the apical sizes used (n = 20); 25/04, 30/04, and 35/04 were the final sizes used. In half the patients of each group, 2.5% sodium hypochlorite was used as an irrigating solution, and in the other half, saline solution was used. After instrumentation, all patients received LA therapy with ICG. Root canal sampling was performed before (S1) and after (S2) root canal instrumentation and immediately after LA therapy with ICG (S3). Colony-forming units were counted, and statistical tests were applied (P < .05). RESULTS: There was a significant reduction in colony-forming units from S1 to S2 in all treatment protocols (P < .05); 2.5% sodium hypochlorite as an irrigating solution showed a greater microbial reduction compared with saline solution (P < .05). LA therapy with ICG further reduced the microbial counts significantly (S2 to S3 and S1 to S3) whether sodium hypochlorite or saline was used (P < .05). CONCLUSIONS: LA therapy with ICG significantly increased microbial reduction in root canals regardless of instrumentation sizes or the irrigation solution used.

Micro-computed tomographic evaluation of the flow and filling ability of endodontic materials using different test models.

OBJECTIVES: This study compared the flow and filling of several retrograde filling materials using new different test models. MATERIALS AND METHODS: Glass plates were manufactured with a central cavity and 4 grooves in the horizontal and vertical directions. Grooves with the dimensions used in the previous study (1 × 1 × 2 mm; length, width, and height respectively) were compared with grooves measuring 1 × 1 × 1 and 1 × 2 × 1 mm. Biodentine, intermediate restorative material (IRM), and mineral trioxide aggregate (MTA) were evaluated. Each material was placed in the central cavity, and then another glass plate and a metal weight were placed over the cement. The glass plate/material set was scanned using micro-computed tomography. Flow was calculated by linear measurements in the grooves. Central filling was calculated in the central cavity (mm3) and lateral filling was measured up to 2 mm from the central cavity. RESULTS: Biodentine presented the least flow and better filling than IRM when evaluated in the 1 × 1 × 2 model. In a comparison of the test models, MTA had the most flow in the 1 × 1 × 2 model. All materials had lower lateral filling when the 1 × 1 × 2 model was used. CONCLUSIONS: Flow and filling were affected by the size of the test models. Higher grooves and materials with greater flow resulted in lower filling capacity. The test model measuring 1 × 1 × 2 mm showed a better ability to differentiate among the materials.

Effects on Bone Tissue After Osteotomy with Different High-Energy Lasers: An Ex Vivo Study.

OBJECTIVE: The purpose of this study was to evaluate the application of Er:YAG and Er,Cr:YSGG lasers during osteotomy in bovine bone blocks. BACKGROUND DATA: Er:YAG/Er,Cr:YSGG lasers for osteotomy procedures have been used to induce tissue ablation without thermal damage. However, even these lasers can induce thermal damages, which can cause a delay on the bone healing. MATERIALS AND METHODS: Sixty standardized bovine bone mandible samples were divided into three groups with 20 samples each: Group 1, Bur; Group 2, Er:YAG laser; and Group 3, Er,Cr:YSGG laser. Two irradiations/cuts were made in each sample. The first was performed until the sample was completely separated into two fragments, and the time required for this procedure was recorded in seconds. The second irradiation/cut was made the same way as the first one; however, it was made partially, without separating the sample into two fragments, but rather making sulci ∼1.5-2 mm deep. Ten samples in each group were used to evaluate the surface morphology of the osteotomy by scanning electron microscopy (SEM), while the other 10 samples were submitted to descriptive histological analysis. RESULTS: The bur was the instrument that performed the osteotomy in the shortest amount of time (p < 0.05). All the instruments caused thermal damage; however, the Er,Cr:YSGG laser was the only type that induced carbonization. CONCLUSIONS: The Er:YAG laser induced the lowest degree of thermal damage in bone tissue after osteotomy; however, a shorter clinical time was required to perform the osteotomy in the bur group.

Solubility and bacterial sealing ability of MTA and root-end filling materials.

Objective To evaluate solubility and sealing ability of Mineral Trioxide Aggregate (MTA) and root-end filling materials. Material and Methods The materials evaluated were: MTA, Calcium Silicate Cement with zirconium oxide (CSC/ZrO2), and zinc oxide/eugenol (ZOE). Solubility test was performed according to ANSI/ADA. The difference between initial and final mass of the materials was analyzed after immersion in distilled water for 7 and 30 days. Retrograde cavities in human teeth with single straight root canal were performed by using ultrasonic tip CVD 9.5107-8. The cavities were filled with the evaluated materials to evaluate sealing ability using the bacterial leakage test with Enterococcus faecalis. Bacterial leakage was evaluated every 24 hours for six weeks observing the turbidity of Brain Heart infusion (BHI) medium in contact with root apex. Data were submitted to ANOVA followed by Tukey tests (solubility), and Kruskal-Wallis and Dunn tests (sealing ability) at a 5% significance level. Results For the 7-day period, ZOE presented highest solubility when compared with the other groups (p<0.05). For the 30-day period, no difference was observed among the materials. Lower bacterial leakage was observed for MTA and CSC/ZrO2, and both presented better results than ZOE (p<0.05). Conclusion MTA and CSC/ZrO2 presented better bacterial sealing capacity, which may be related to lower initial solubility observed for these materials in relation to ZOE.

Solubility and bacterial sealing ability of MTA and root-end filling materials

ABSTRACT Objective To evaluate solubility and sealing ability of Mineral Trioxide Aggregate (MTA) and root-end filling materials. Material and Methods The materials evaluated were: MTA, Calcium Silicate Cement with zirconium oxide (CSC/ZrO2), and zinc oxide/eugenol (ZOE). Solubility test was performed according to ANSI/ADA. The difference between initial and final mass of the materials was analyzed after immersion in distilled water for 7 and 30 days. Retrograde cavities in human teeth with single straight root canal were performed by using ultrasonic tip CVD 9.5107-8. The cavities were filled with the evaluated materials to evaluate sealing ability using the bacterial leakage test with Enterococcus faecalis. Bacterial leakage was evaluated every 24 hours for six weeks observing the turbidity of Brain Heart infusion (BHI) medium in contact with root apex. Data were submitted to ANOVA followed by Tukey tests (solubility), and Kruskal-Wallis and Dunn tests (sealing ability) at a 5% significance level. Results For the 7-day period, ZOE presented highest solubility when compared with the other groups (p<0.05). For the 30-day period, no difference was observed among the materials. Lower bacterial leakage was observed for MTA and CSC/ZrO2, and both presented better results than ZOE (p<0.05). Conclusion MTA and CSC/ZrO2 presented better bacterial sealing capacity, which may be related to lower initial solubility observed for these materials in relation to ZOE.

Effectiveness of gutta-percha and Resilon in filling lateral root canals using thermomechanical technique / Eficácia da guta-percha e Resilon na obturação de canais laterais usando técnica termomecânica

Objetivo: O objetivo do estudo foi avaliar a efetividade da guta-percha e Resilon no preenchimento de canais laterais nos terços cervical, médio e apical radicular quando utilizada a técnica termomecânica. Material e Método: Canais radiculares de dentes artificiais foram preparados utilizando um método padrão. Canais laterais foram confeccionados utilizando broca com 0,3 mm de diâmetro nos três terços radiculares. Os canais radiculares foram obturados pela técnica híbrida de Tagger utilizando-se o compactador de McSpadden. Foi avaliado o preenchimento dos canais laterais pelos seguintes materiais: cones de guta-percha Dentsply, guta-percha Endopoint e Resilon. A avaliação foi realizada por meio da análise de radiografias digitalizadas usando o programa Image Tool. A porcentagem da área preenchida pela área total de cada canal lateral foi determinada. Os dados foram submetidos à análise de variância (ANOVA) e teste de Tukey com nível de significância de 5%. Resultado: O Resilon mostrou melhor efetividade como material de preenchimento. Na comparação entre os terços, o Resilon foi mais efetivo no terço apical que no cervical (p < 0,05). Conclusão: O Resilon foi o material mais efetivo para o preenchimento dos canais laterais quando utilizada a técnica termoplástica.

Objective: The aim of this study was to evaluate the effectiveness of gutta-percha and Resilon in filling lateral root canals in cervical, middle, and apical third using a thermomechanical technique. Material and Method: Root canals of artificial teeth were prepared using a standard preparation. The lateral canals were fabricated using a 0.3-mm-diameter bur at 3 parts of each root. By using Tagger's hybrid technique with a McSpadden thermomechanical compactor, the root canal was filled using the following filling materials: Dentsply gutta-percha, Endopoint gutta-percha, and Resilon cones. The root canal fillings were evaluated using digitized radiographs and the Image Tool software. The percentage of filled area of each lateral canal was determined. The data were subjected to analysis of variance (ANOVA) and Tukey tests at a 5% significance level. Result: Resilon showed better effectiveness as a filling material. When the three thirds were compared, Resilon was more effective in the apical third than in the cervical third (p < 0.05). Conclusion: Resilon is an effective filling material for lateral root canals using a thermomechanical technique.

Cleaning capacity promoted by motor-driven or manual instrumentation using ProTaper Universal system: Histological analysis.

AIM: The aim of this study was to assess the cleaning capacity of the Protaper system using motor-driven or manual instrumentation. MATERIALS AND METHODS: Ten mandibular molars were randomly separated into 2 groups (n = 5) according to the type of instrumentation performed, as follows: Group 1 - instrumentation with rotary nickel-titanium (Ni-Ti) files using ProTaper Universal System (Dentsply/Maillefer); and, Group 2 - instrumentation with Ni-Ti hand files using ProTaper Universal (Dentsply-Maillefer). Afterwards, the teeth were sectioned transversely and submitted to histotechnical processing to obtain histological sections for microscopic evaluation. The images were analyzed by the Corel Photo-Paint X5 program (Corel Corporation) using an integration grid superimposed on the image. RESULTS: Statistical analysis (U-Mann-Whitney - P < 0.05) demonstrated that G1 presented higher cleaning capacity when compared to G2. CONCLUSIONS: The rotary technique presented better cleaning results in the apical third of the root canal system when compared to the manual technique.

Adaptação marginal do agregado de trióxido mineral com e sem cloreto de cálcio em retrocavidades / Marginal adaptation of the Mineral Trioxide Aggregate with and without calcium chloride in root-end cavities

Objetivo: Avaliar a adaptação marginal do Agregado de Trióxido Mineral (MTA) com e sem cloreto de cálcio (CaCl2) em retrocavidades. Método: Vinte dentes unirradiculados foram instrumentados e obturados com gutapercha e AH-Plus. Os ápices das raízes foram cortados com uma broca Zekrya e preparos retrógrados foram realizados com pontas ultrassônicas. Réplicas em resina dos ápices preparados foram obtidas, metalizadas com ouro e examinadas em microscopia eletrônica de varredura (MEV). Os espécimes foram divididos em dois grupos experimentais (n = 10 dentes), de acordo com o material retrobturador empregado: G1 ­ MTA e G2 ­ MTA + CaCl2. Após as retrobturações, os dentes foram mantidos em ambiente úmido a 37 °C por 24 horas. Novas réplicas de resina foram obtidas e levadas ao MEV. A adaptação marginal dos cimentos foi classificada como: 1) margem contínua; 2) margem não contínua. Além disso, os percentuais de margem contínua foram calculados. Os resultados foram analisados pelo teste de Mann-Whitney. Resultados: Falhas de adaptação foram observadas em duas raízes no G1 e três raízes no G2. O percentual de margem contínua foi de 95,59% no grupo com MTA e 87,48% no grupo com MTA + CaCl2 . Não houve diferença estatística significativa entre os dois grupos (p > 0,05). Conclusão: A adição do cloreto de cálcio ao MTA não alterou a sua capacidade de adaptação marginal às paredes dentinárias das retrocavidades.

Objective: To evaluate the marginal adaptation of the Mineral Trioxide Aggregate (MTA) with and without calcium chloride (CaCl2) in root-end cavities. Method: Twenty extracted single-rooted teeth were instrumented and obturated with gutta-percha and AH Plus. All roots were resected using a Zekrya bur and root-end cavities were prepared by using ultrasonic retrotips. Epoxy resin replicas of root-end surfaces after root-end cavity preparation were obtained, sputter coated with gold, and examined by using a scanning electron microscope (SEM). The sampleswere divided into two experimental groups (n = 10 teeth) according to the root-end filling material employed: G1 - MTA; and G2 - MTA + CaCl2. After the root-end filling, the teeth were stored in moist gauze at 37 °C for24 hours. New replicas of the root-end surfaces were obtained and examined under a SEM. Marginal adaptation of the filling materials were categorized as: 1) continuous margin; 2) non-continuous margin. Besides, percentages of continuous margin were calculated. The results were analyzed by the Mann-Whitney test. Results: Visible gaps were seen in 2 roots in G1 and in 3 roots in G2. A continuous margin was observed with 95,59% of MTA and 87,48% of MTA + CaCl2 root-end fillings. There was not statistical difference between the two groups (p > 0.05).Conclusion: The addition of CaCl2 to MTA did not alter its marginal adaptation capability to the dentin walls of root-end cavities.

Quantification of fibrosis and mast cells in the tissue response of endodontic sealer irradiated by low-level laser therapy.

Low-level laser therapy (LLLT) accelerates tissue repair. Mast cells induce the proliferation of fibroblasts and the development of local fibrosis. The objective of this study was to quantify fibrosis rate and mast cells in connective tissue after endodontic sealer zinc oxide and eugenol (ZOE) was implanted and submitted to LLLT, immediately after implant and again 24 h later. Sixty mice were distributed into three groups: GI, GII, and GIII (n = 20). In GI, the tubes filled with Endofill were implanted in the animals and were not irradiated with LLLT. In GII, the tubes containing Endofill were implanted in the animals and then irradiated with red LLLT (InGaAIP) 685-nm wavelength, D = 72 J/Cm(2), E = 2 J, T = 58 s, P = 35 mW, and in GIII, the tubes with Endofill were implanted and irradiated with infrared LLLT (AsGaAl) 830-nm wavelength, D = 70 J/Cm(2), E = 2 J, T = 40 s, P = 50 mW. After 7 days and 30 days, the animals were killed. A series of 6-µm-thick sections were obtained and stained with Toluidine Blue and Picrosirius and analyzed under a standard light microscope using a polarized light filter for the quantification of fibrosis. The statistics were qualitative and quantitative with a significance of 5%. The irradiation with LLLT did not offer improvement in the fibrosis rate, however, it provided a significant decrease in the concentration of independent mast cells for the period studied.

Apical sealing quality of in vitro apicectomy procedures after using both Er:YAG and Nd:YAG.

The aim of this study was to evaluate the apical sealing of dentinal tubules after root-end surface cutting by using Er:YAG and Nd:YAG lasers. After root-canal instrumentation and filling, apices of 50 extracted maxillary canine human teeth were resected by Er:YAG with 400 mJ, 10 Hz, for 30 sec. The samples were randomly assigned to five groups (n = 10): (GI) treated without root-end cavity, but with Nd:YAG (1.0 W, 10 Hz, 20 sec) for dentinal tubules sealing; (GII) treated with root-end cavity without the use of Nd:YAG; (GIII) treated with root-end cavity and Nd:YAG application; (GIV) treated with root-end cavity made by Er:YAG with no focus and without Nd:YAG application; and (GV) treated without root-end cavity and without Nd:YAG application. The root-end cavities were performed by using Er:YAG at 300 mJ, 10 Hz, for 20 sec. Subsequently, all teeth were waterproofed and immersed in 2% methylene blue for 48 h in a vacuum environment. The samples were longitudinally sectioned, and microleakage was measured. ANOVA and the Fisher LSD test showed that GIV was less susceptible to microleakage than were the other groups (p < 0.05). Interestingly, the use of the Er:YAG with no focus showed superior dentinal tubule sealing in comparison with the other groups, even with or without root-end cavity and Nd:YAG application.

Retratamento endodôntico empregando a nova geração de instrumentos rotatórios de níquel-titânio: relato de caso / Endodontic retreatment using the new generation of nickel-titanium rotary instruments: report of 2 cases

A remoção segura e eficiente do material obturador dos canais radiculares é essencial para o sucesso do retratamento endodôntico. A utilização de limas manuais com ou sem o auxílio de solventes para remoção do material obturador consome tempo, especialmente quando a obturação do canal radicular apresenta boa condensação. Os instrumentos rotatórios de níquel-titânio têm sido usados satisfatoriamente na limpeza e modelagem de canais radiculares. As vantagens dos instrumentos rotatórios incluem a manutenção da forma do canal e o menor tempo de trabalho, enquanto que a maior incidência de fraturas de lima e a maior quantidade d ematerial remanescente após retratamento constituem pontos negativos. Recentemente, uma nova geração de limas rotatórias de níquel-titânio, o ProTaper Universal Retratamento, o R-Endo e o Mtwo R, foi desenvolvida. Elas foram projetadas especificamente para remoção d ematerial obturador nos casos de retratamento. O objetivo deste artigo é relatar dois casos de retratamento empregando as limas ProTaper Universal Retratamento e R-Endo...

Safe and efficient removal of filling material from canal systems is essential for optimal root canal retreatment. Removal of gutta-percha using hand files with or without solvents is time-consuming, especially when the filling materials are well condensed. Nickel-titanium rotary instruments have been used successfully in root canal cleanign and shaping. Advantages of rotary instruments include maintenence of canal shape and shorter working time, whereas disadvantages include higher incidence of file fracture and momre remaining filling material after retreatment. Recently, a new generation of nickel-titanium rotary instruments, ProTaper Universal Retreatment, R-Endo and Mtwo R, became available. They have been designed specifically for root filling removal in case of retreatment. This paper reports two cases of retreatment using ProTaper Universal Retreatment and R-Endo files...

In vitro evaluation of the obturation ability, adaptation and compaction of gutta-percha in the root canal system employing different filling techniques.

The aim of this study was to evaluate the in vitro obturation quality of four filling methods: active lateral condensation, a modification of Tagger's hybrid technique, ENAC ultrasound technique and the Microseal technique. The study was performed on one hundred and sixteen single-rooted human teeth, divided into four groups of twenty nine teeth, embedded in resin, longitudinally sectioned and placed together on a wooden device with screws. After instrumentation, a cavity was made with a bur in the cervical, medium and apical thirds of the root canal in order to simulate lateral canals. The teeth were filled with the different techniques. Obturation quality was evaluated employing photographs and radiographs. The statistical analysis using the Chi square (chi2) test revealed that the Microseal technique reached the best results followed by the modified Tagger's hybrid technique, the ENAC ultrasound technique and the active lateral condensation technique.

pH changes after manual or ultrasonic instrumentation and smear layer removal with EDTA or ultrasonic.

The purpose of the present study was to evaluate the influence of instrumentation techniques associated with the smear layer removal, in the pH changes of the root surface. Thirty mandibular humans premolars were divided into three groups: Group I - instrumentation by Ohio technique and final cleaning with EDTA (3 minutes); Group II - instrumentation by Ohio technique and final cleaning with ultrasonic (1 minute); Group III - instrumentation by the ultrasonic technique and final cleaning with ultrasonic (1 minute). The pH was measured in the cavities prepared in the cervical, middle and apical thirds of the lateral wall of each root. The teeth were evaluated at the initiation of the experiment, and 3, 7, 14, 21, 30 days after of the intracanal dressing of the calcium hydroxide with camphorated p-monochlorophenol (Calen/PMCC). All the groups presented increasing pH values; group III presented the highest average pH, followed by groups II and I; the values for the apical third were lower than those of the middle and cervical thirds (anova and Tukey test). The results showed that the biomechanical preparation by the ultrasonic technique and smear layer removal with ultrasonic showing the highest diffusion of the calcium and hydroxyl ions from the intracanal dressing (P < 0.05).

Selamento apical em obturações retrógradas. Estudo em dentes bovinos empregando solução corante Rodamina B / Apical sealing in retrograde fillings. Study in bovine teeth using Rhodamine B dye solution

A capacidade de selamento de materiais utilizados em endodontia tem sido avaliada por testes de infiltração com corantes. A proposta deste estudo foi avaliar o selamento apical de materiais utilizados em obturações retrógradas empregando modelo experimental com dentes bovinos. Quarenta incisivos bovinos recém extraídos, com raízes retas tiveram seus canais radiculares instrumentados e obturados. Após a secção da porção apical, cavidades retrógradas foram preparadascom pontas de retropreparo ultra-sônico e os dentes divididos aleatoriamente em três grupos experimentais (n=12) equatro controles (n=4). Foram utilizados os materiais: Grupo I - MTA Angelus Cinza; Grupo II - Cimento de Óxido Zinco e Eugenol; Grupo III - Sealer 26. Em seguida, os dentes foram imersos em solução de Rodamina B a 0,2 % por 48 horas em ambiente com vácuo. Decorrido este período, os dentes foram seccionados longitudinalmente e as imagens digitalizadas analisadas por meio do programa Image Tool. Grupos controle positivo e negativo apresentaram infiltração máxima ou zero, respectivamente. Os resultados obtidos foram submetidos ao teste ANOVA e de Tukey demonstrandomenor infiltração apical para o Sealer 26 (p<0,05). MTA e OZE apresentaram infiltração apical semelhante (p>0,05).Conclui-se que o cimento Sealer 26 proporciona selamento apical superior ao MTA e OZE, sendo o modelo experimental com dentes bovinos viável para a avaliação do selamento apical em obturações retrógradas.

Efeito do desgaste da linha de cimento, da vibração ultra-sônica e da associação de ambas sobre a força de tração empregada na remoção de pinos intra-radiculares / Effect of wearing in cement line, of the ultrasonic vibration and of the association of both on the tensile stress employed in the removal of intraradicular posts

O presente estudo avaliou o efeito de diferentes meios auxiliares e associações sobre a força de tração empregada na remoção de pinos intra-radiculares. Foram selecionados 50 dentes pré-molares inferiores extraídos de humanos que tiveram suas coroas removidas, os canais radiculares submetidos ao preparo biomecânico e posterior obturação. Os 7 mm cervicais dos canais radiculares tiveram as obturações removidas e foram preparados e submetidos à moldagem para confecção dos núcleos, sendo estes cimentados com cimento de fosfato de zinco. Decorridos 48 horas, cada grupo de 10 raízes foi submetido a, respectivamente: desgaste + ultra-som linha de cimento + tração (Grupo I), desgaste + ultra-som porção coronária do núcleo + tração (Grupo II), ultra-som porção coronária do núcleo + tração (Grupo III), desgaste + tração (Grupo IV) e tração simples (Grupo V). O último passo deu-se em máquina de tração, onde a força necessária para a tração do pino foi determinada por meio de um programa de computador especializado. Os resultados foram submetidos à análise estatística, comprovando maior efetividade e segurança na remoção dos pinos intra-radiculares, quando se utilizou a associação dodesgaste mais ultra-som na linha de cimento e tração (Grupo I)

Influence of root canal dressings and sealers on repair of apical periodontitis after endodontic treatment.

OBJECTIVE: The objective of this study was to evaluate the histopathologic response of periapical tissues after root canal treatment of necrotic dog teeth with chronic apical periodontitis by using 2 calcium hydroxide-based root canal dressings and 2 root canal sealers. STUDY DESIGN: Seventy-eight root canals were instrumented by using 5.25% sodium hypochlorite as the irrigating solution, after which a calcium hydroxide paste (Calen/PMCC or Calasept) was placed for 30 days as a dressing. The root canals were then filled by using cold lateral gutta-percha condensation and an endodontic sealer (Sealapex or AH Plus). After 360 days, the animals were killed by anesthetic overdose; then, the teeth were histologically prepared, sectioned, and stained with hematoxylin and eosin for optical microscopic analysis of apical and periapical tissue repair. RESULTS: Statistical analysis showed that the poorest histopathologic results were observed in the Calasept/AH Plus group and that the Sealapex sealer overall resulted in better apical repair than the AH Plus sealer. The histopathologic results of Calen/PMCC paste with both AH Plus and Sealapex and Calasept paste with only Sealapex were statistically similar but were different from the results of Calasept with AH Plus. CONCLUSIONS: The results of this study in the dog showed differences in apical and periapical tissue repair of teeth with chronic apical periodontitis by using 2 calcium hydroxide root canal dressings and 2 sealers. More research is necessary to determine the best combination of dressings and sealers.

Quelantes em endodontia / Chelating agents in endodontics

Revisäo de literatura sobre o uso de quelantes, particularmente o EDTA, em endodontia. Säo abordados os seguintes aspectos: definiçäo de quelaçäo, as propriedades químicas e o modo de açäo EDTA e sua aplicaçäo em endodontia

Análise histológica da reparaçäo apical e periapical pós-tratamento endodôntico de dentes de cäes com reaçäo periapical crônica induzida, em funçäo do curativo de demora com Calen/PMCC ou Calasept, e da obturaçäo do canal radicular com Sealapex ou AH Plus / Histological analysis of endodontic post-treatment periapical and apical reparation of dog's teeth with induced periapical periodontitis, in function of temporary dressing with Calen/PMCC or Calasept, and of root canal filling with Sealapex or AH Plu

Foram utilizados 78 canais radiculares de dentes de 6 cäes, sem vitalidade pulpar e com reaçäo periapical crônica induzida. Após o preparo biomecânico utilizando o hipoclorito de sódio a 5,25 por cento como soluçäo irrigadora, os canais radiculares receberam as pasta à base de hidróxido de cálcio Calen com PMCC ou Calasept como curativo de demora por 30 dias. Decorrido este período, os canais radiculares foram obturados com guta-percha e o cimento endodôntico Sealapex ou guta-percha e AH Plus empregando-se a técnica de condensaçäo lateral da guta-percha e tiveram suas aberturas coronárias seladas com amálgama. Após o período de 360 dias, os animais foram sacrificados por sobredose anestésica e as peças submetidas ao processamento histológico. Os cortes histológicos com 6 µm de espessura foram corados pela Hematoxilina e Eosina, sendo submetidos à microscopia óptica para a avaliaçäo do reparo apical e periapical. Os resultados demonstraram que o grupo Calasept AH Plus apresentou os piores resultados histopatológicos, com significância estatística quanto ao infiltrado inflamatório, selamento apical biológico, reabsorçäo óssea e espessura do ligamento periodontal. O cimento Sealapex mostrou melhores resultados histopatológicos do que o AH Plus. A pasta Calen/PMCC comportou-se ecleticamente bem com ambos os cimentos obturadores, e a pasta Calasept mostrou sugestivamente sinergismo com o Sealapex e antagonismo com o AH Plus