Alexandre Silva Bramante

Heat release, time required, and cleaning ability of MTwo R and ProTaper universal retreatment systems in the removal of filling material.

INTRODUCTION This ex vivo study evaluated the heat release, time required, and cleaning efficacy of MTwo (VDW, Munich, Germany) and ProTaper Universal Retreatment systems (Dentsply/Maillefer, Ballaigues, Switzerland) and hand instrumentation in the removal of filling material. METHODS Sixty single-rooted human teeth with a single straight canal were obturated with gutta-percha and zinc oxide and eugenol-based cement and randomly allocated to 3 groups (n = 20). After 30-day storage at 37 °C and 100% humidity, the root fillings were removed using ProTaper UR, MTwo R, or hand files. Heat release, time required, and cleaning efficacy data were analyzed statistically (analysis of variance and the Tukey test, α = 0.05). RESULTS None of the techniques removed the root fillings completely. Filling material removal with ProTaper UR was faster but caused more heat release. Mtwo R produced less heat release than the other techniques but was the least efficient in removing gutta-percha/sealer. CONCLUSIONS ProTaper UR and MTwo R caused the greatest and lowest temperature increase on root surface, respectively; regardless of the type of instrument, more heat was released in the cervical third. Pro Taper UR needed less time to remove fillings than MTwo R. All techniques left filling debris in the root canals.

Root Canal Area Increase Promoted by the EndoSequence and ProTaper Systems: Comparison by Computed Tomography

INTRODUCTION The aim of this study was to compare the increase of the root canal area after instrumentation with EndoSequence or ProTaper rotary systems. METHODS Twenty-two mesial root canals from mandibular molars were instrumented. Teeth were mounted on a base, numbered, and divided into 2 groups; teeth from 1-11 (PT group) were instrumented by using the ProTaper system, and teeth from 12-22 (ES group) were instrumented by using the EndoSequence system. Cone beam computed tomography was performed on all teeth before and after instrumentation. Measurements at 3, 5, and 7 mm as well as differences in instrument performance were statistically compared by the Student t test at 5% significance level. RESULTS Both systems increased significantly the root canal area (P < .05) at all levels. Comparison between the rotary systems showed significantly greater increase (P < .05) for EndoSequence at 3 mm, with no statistically significant difference (P < .05) at the other levels. CONCLUSIONS Both rotary systems increased significantly the root canal area.

Biocompatibility and setting time of CPM-MTA and white Portland cement clinker with or without calcium sulfate

Objective: To evaluate the biocompatibility and the setting time of Portland cement clinker with or without 2% or 5% calcium sulfate and MTA-CPM. Material and Methods: Twenty-four mice (Rattus norvegicus) received subcutaneously polyethylene tubes filled with Portland cement clinker with or without 2% or 5% calcium sulfate and MTA. After 15, 30 and 60 days of implantation, the animals were killed and specimens were prepared for microscopic analysis. For evaluation of the setting time, each material was analyzed using Gilmore needles weighing 113.5 g and 456.5 g, according to the ASTM specification Number C266-08 guideline. Data were analyzed by ANOVA and Tukeys test for setting time and Kruskal-Wallis and Dunn test for biocompatibility at 5% significance level. Results: Histologic observation showed no statistically significant difference of biocompatibility (p>0.05) among the materials in the subcutaneous tissues. For the setting time, clinker without calcium sulfate showed the shortest initial and final setting times (6.18 s/21.48 s), followed by clinker with 2% calcium sulfate (9.22 s/25.33 s), clinker with 5% calcium sulfate (10.06 s/42.46 s) and MTA (15.01 s/42.46 s). Conclusions: All the tested materials showed biocompatibility and the calcium sulfate absence shortened the initial and final setting times of the white Portland cement clinker.

Evaluation of the effects of processing delays and protective plastic cases on image quality of a photostimulable phosphor plate system

This ex vivo study evaluated the quality of digital radiographic images obtained with the photostimulable phosphor plate system (Digora) according to the processing delay and maintenance of optical plates in either opaque (supplied with the system) or transparent protective plastic cases during this period. Five radiographs were obtained from the mandibular molar region of a dry human mandible using optical plates. These plates were placed in the protective plastic cases before obtaining the radiographs and were processed immediately or after processing delays of 5, 60 and 120 min, when the case was removed. The results revealed a reduction in image quality when processing was delay 120 min compared to the other times. The opaque case provided better protection to the sensor than the transparent case. In conclusion, a 120-min processing delay for the Digora system caused a reduction in image quality, yet without interfering with the quality of diagnosis. The opaque case supplied by the systems manufacturer provided better protection to the optical plate than the transparent case.

Use of a 660-nm Laser to Aid in the Healing of Necrotic Alveolar Mucosa Caused by Extruded Sodium Hypochlorite: A Case Report

The extrusion of sodium hypochlorite through the apical foramen is an accident that can occur during the flushing procedure in endodontic treatment. The symptomatology is immediate and intense, and there is a long period before the tissues return to normal. Low-level laser therapy might be useful as an adjunctive treatment for damaged soft tissues because of its anti-inflammatory and analgesic effects, which may reduce edema and prevent infection. In this clinical case, the accidental leakage of 1% sodium hypochlorite during the preparation of the root canal of a maxillary right central incisor is reported. This leakage caused immediate and intense pain and edema formation and resulted in an extensive necrotic area in the alveolar mucosa adjacent to the root of the treated tooth. The conventional treatment protocol was combined with low-level laser therapy. Clinical and radiographic examinations after 7 months revealed complete repair of the necrotic area with no paresthesia and further indicated the integrity of the apical region of the tooth where the extrusion of sodium hypochlorite occurred. The combination of low-level laser therapy with a conventional treatment protocol in this case of the extrusion of 1% sodium hypochlorite resulted in the healing of the wounds.

Diagnóstico de Defeitos Ósseos por Meio da Radiografia Convencional, Digital e Tomografia Helicoidal

This study evaluated the accuracy of, conventional and digital radiography and helicoidal tomography images in localizing and visualizing experimental bone defects. Dry human mandibles with good bone integrity in the evaluated regions were selected. The bone defects were performed in the socket of posterior teeth, with # 2, 6 and 10 spherical burs. The mandibles were radiographed with an Insight Plus IP-21 Kodak film, digital radiography system (Digora) and helicoidal tomographs. The visualization of bone defects was performed in the radiographic images and helicoidal tomography, with the aid of a viewbox; in the digital images, it was performed in the computer screen, with the support of Windows for Digora. Images obtained with helicoidal tomography were superior to radiographic and digital images in detecting bone defects, confined to marrow bone.

Influência da penetração de instrumentos, empregados na condensação lateral ativa, na qualidade da obturação de canais radiculares

ABSTRACT Purpose: the purpose of this study was to comparethe quality of the obturation and the difference ofpenetration depth inside the root canal of theinstruments Finger Spreader, file type Kerr, Flexofileand Nitiflex when used as spreaders during the fillingby Active Lateral Condensation Technique. Materialand Method: 40 extracted permanent human teeth wereinstrumented by the Modified Goerig Technique anddivided in four groups. In the group I the fingerspreader was used; in the group II, files type Kerr wasused; in the group III, files Flexofile was used and, inthe group IV, files Nitiflex, all number 30, for spaceopening for placement of the secondary cones, duringthe Technique of Active Lateral Condensation. Theradiographic quality of the obturation and the depthof penetration of the instruments was evaluated andanalysed statisticaly (Kruskal-Wallis and Dunn’s Test).Results and Conclusion: with relationship to theradiograph analysis of the quality of the filling, thegroup II was what it presented the best result, followedby the groups I, IV and III, respectively. In relation tothe depth of penetration of the instruments, the groupIV approached more the desired distance, or, 1millimeter less than the length of the work, followed,respectively, by groups II, III and I.

Avaliação do sistema Quantec SC usado nas velocidades de 350 ou 700rpm em retratamento endodôntico

O objetivo deste estudo foi analisar a capacidade do sistema rotatorio Quantec SC de remover guta-percha e/ou cimento de canais quando usado na velocidade de 350 ou 700rpm. Vinte incisivos inferiores extraidos foram obturados pela tecnica da condensacao lateral com guta-percha e cimento Ketac-Endo. Apos seis meses as obturacoes foram removidas com o sistema rotatorio Quantec SC na velocidade de 350 ou 700rpm. Inicialmente foram avaliados o tempo para a remocao da obturacao, a extrusao de material obturador bem como o desvio do trajeto do canal, perfuracao e a fratura de instrumento. A seguir os dentes foram seccionados longitudinalmente e a limpeza das paredes dos canais foi avaliada usando o software Sigma Scan. Aos dados obtidos foi aplicado o teste estatistico de Kruskal-Wallis. Observou-se que todos os canais exibiram residuos de material obturador; a 700rpm o tempo de remocao da obturacao foi menor, porem, a 350rpm menor quantidade de residuos de guta-percha e cimento foram observadas. Quanto a extrusao de material obturador, nao foram observadas diferencas estatisticas entre as velocidades de 350 e 700rpm. Fraturas de instrumento ocorreram em ambas as velocidades sendo mais frequentes no instrumento no5; o numero de perfuracoes e desvios do trajeto do canal foi maior na velocidade de 350rpm. Conclui-se que os instrumentos rotatorios do sistema Quantec SC podem ser utilizados para desobstrucao de canais na velocidade de 700rpm.

Análise de Defeitos Ósseos Utilizando a Radiografia Convencional e Sistema de Imagem Digital Digora

Resumo Foi avaliada a precisao das imagens digitais, obtidas com o Sistema Digora e radiografias convencionais, na localizacao e visualizacao de defeitos osseos criados experimentalmente, em mandibulas humanas secas. As imagens digitalizadas, padrao, 3D e com inversao de contraste, foram comparadas com as radiografias convencionais, obtidas com filmes Ekta-speed Plus EP-21 da Kodak. Os resultados mostraram que os defeitos produzidos no osso cortical foram melhores detectados do que os do osso esponjoso. A radiografia convencional foi a que melhor mostrou o defeito do osso cortical e a digitalizada no osso esponjoso. Entre as digitalizadas a melhor foi a padrao e com inversao de contraste. Em todas as imagens, radiografia convenciona e digitalizadas os defeitos somente foram visualizados quando alcancou o tamanho de uma broca numero 6.

Determinação do comprimento de dentes em função da posição da placa óptica do sistema de imagem digital Digora em relação ao eixo dentário

The aim of this article was to investigate the influence of the position of the imaging plate of the Digora digital system in the determination of tooth length. Sixty extracted human teeth were evaluated, divided into: ten maxillary incisors, ten mandibular incisors, ten maxillary bicuspids, ten mandibular bicuspids, ten maxillary molars, and ten mandibular molars. They were radiographed with the Digora imaging plate in two positions: long axis of the tooth parallel to the length of the plate, and long axis of the tooth parallel to the width of the same. The digital radiographic measurements of the specimens were obtained with the Digora system. The results showed no statistically significant differences between the digital radiographic measurements in either position, except for maxillary bicuspids and distal root of mandibular molars, although this difference was not clinically significant.