How does nano-focus computed tomography impact the quantification of debris within the root canal system?

Abstract The aim of this study was to compare the quantification of hard-tissue debris by using micro-computed tomography (micro-CT) and nano-focus computed tomography (nano-CT) after root canal instrumentation. Ten mandibular molars containing an isthmus in the mesial root were scanned in a SkyScan 1172 micro-CT device with a voxel size of 12.8 µm and in a NanoTom nano-CT device with 5.5 µm. The mesial root canals were irrigated with 5 mL of saline solution at the orifice level, instrumented with Reciproc R25 files and a second scanning was performed by micro-CT and nano-CT devices for post-instrumentation images. DataViewer software was used for registering the pre- and post-operative micro-CT and nano-CT images. The root canal and the debris were segmented for quantitative analysis of the volume of the canal and volume of debris using CTAn software. Statistical analysis was performed using the T test for comparison between volume of the canal after instrumentation and volume of debris in both image modalities. The level of significance was set at p < 0.05. Nano-CT images showed higher values of debris when compared with micro-CT (p < 0.05) after root canal instrumentation. No difference was observed between the volume of the root canal after instrumentation in the two imaging methods used (p > 0.05). Nano-CT technology can be recommended as a more precise method for quantitative analysis of hard-tissue debris. Moreover, in Endodontic research it is a promising method, as it is capable of providing higher spatial and contrast resolution, faster scanning and higher image quality.

Influence of working length and anatomical complexities on the apical root canal filling: a nano-CT study

Abstract The present study aimed to compare the filled volume by gutta-percha and sealer in the apical region of the main canal and ramifications, after instrumentation at two different working lengths using nano-computed tomography (nano-CT). Twenty-two premolars with apical ramifications were selected after micro-computed tomography evaluation and were randomly divided into groups for further endodontic instrumentation at two different working lengths: G1 - Root canals shaped 1 mm short of the apical foramen (n=11), and G2 - Root canals shaped at the apical foramen (n=11). After completing root treatment, nano-CT images were acquired, and the filled volume by gutta-percha and sealer in the main canal apical 0-4 mm and 0-1 mm ranges, and apical ramifications were objectively measured by an operator specialized in both radiology and endodontics, blinded for both groups. The Mann-Whitney test was applied to compare both groups regarding the filling of the main canal apical ranges and apical ramifications with a significance level of 5% (α ≤ 0.05). It was observed that root canals shaped at the apical foramen had a larger volume of the main canal filled than root canals shaped 1 mm short of the apical foramen, at both apical ranges (0-4 and 0-1 mm) (p<0.05). Regarding the filling of the apical ramifications, there was no significant difference between groups (p>0.05). In conclusion, the root canals shaped at apical foramen exhibited increased filling volume of the main canal in the apical region. However, neither of both working lengths influenced filling of the apical ramifications.

Resumo O presente estudo teve como objetivo comparar o volume preenchido por guta-percha e cimento na região apical do canal principal e ramificações, após instrumentação em dois comprimentos de trabalho diferentes, por meio de nano tomografia computadorizada (nano-TC). Vinte e dois pré-molares com ramificações apicais foram selecionados após avaliação por micro-tomografia computadorizada e foram divididos aleatoriamente em grupos para posterior instrumentação endodôntica em dois comprimentos de trabalho diferentes: G1 - Canais radiculares instrumentados 1 mm aquém do forame apical (n = 11) e G2 - Canais radiculares instrumentados até o forame apical (n = 11). Após a obturação dos canais radiculares, imagens de nano-CT foram adquiridas, e o volume preenchido por guta-percha e cimento nas faixas apicais de 0-4 mm e 0-1 mm do canal principal, e ramificações apicais, foram avaliadas objetivamente por um especialista em radiologia e endodontia, cego para ambos os grupos. O teste de Mann-Whitney foi aplicado para comparar os dois grupos quanto ao preenchimento das faixas apicais do canal principal e ramificações com nível de significância de 5% (α ≤ 0,05). Observou-se que canais radiculares instrumentados até o forame apical apresentaram maior volume do canal principal preenchido do que canais radiculares instrumentados 1 mm aquém do forame apical, em ambas as faixas apicais (0-4 e 0-1 mm) (p <0,05) Em relação ao preenchimento das ramificações apicais, não houve diferença significativa entre os grupos (p> 0,05). Em conclusão, os canais radiculares instrumentados até o forame apical mostraram um maior volume de preenchimento na região apical do canal principal. No entanto, os dois diferentes comprimentos de trabalho não influenciaram o preenchimento das ramificações apicais.

CBCT Post-Processing Tools to Manage the Progression of Invasive Cervical Resorption: A Case Report

Abstract This case report aimed to highlight the usefulness of cone beam computed tomography (CBCT) and its post-processing tools for the diagnosis, follow-up and treatment planning of invasive cervical resorption (ICR). A 16-year-old female patient was referred for periapical radiographic examination, which revealed an irregular but well demarcated radiolucency in the mandibular right central incisor. In addition, CBCT scanning was performed to distinguish between ICR and internal root resorption. After the diagnosis of ICR, the patient was advised to return shortly but did so only six years later. At that time, another CBCT scan was performed and CBCT registration and subtraction were done to document lesion progress. These imaging tools were able to show lesion progress and extent clearly and were fundamental for differential diagnosis and treatment decision.

Resumo Com este relato de caso clínico objetiva-se enfatizar a contribuição das ferramentas de pós-processamento aplicadas às imagens de tomografia computadorizada de feixe cônico (TCFC) no diagnóstico, acompanhamento e decisão do tratamento de reabsorção cervical invasiva (ICR). Paciente do sexo feminino, com 16 anos de idade foi encaminhada para realização de radiografia periapical e foi observada radiolucência irregular, na raiz do incisivo central inferior direito. A TCFC foi realizada no intuito de se obter diagnóstico diferencial entre ICR e reabsorção radicular interna. Após o diagnóstico de ICR, o paciente foi orientado a retornar em breve, mas o fez somente seis anos mais tarde. Fez-se assim outra tomografia e registro e subtração foram realizados para documentar a progressão da lesão. Essas ferramentas foram capazes de revelar claramente o progresso da lesão, sua real extensão e foram fundamentais para o diagnóstico diferencial e decisão de tratamento.

Racionalización de la dosis de radiación / Streamlining the radiation dose

En la actualidad existe una gran aceptación por la medicina y la odontología, en que la práctica clínica debe ser ôbasada en evidencia científicaõ, tanto como sea posible. Es por eso que múltiples trabajos se han publicado orientados a disminuir las dosis de radiación en los diferentes tipos de modalidades imaginológicas usados en la odontología, ya que el mayor efecto de las radiaciones, sobre todo en niños, nos obliga a tomar medidas necesarias para racionalizar su uso, especialmente con la tomografía computarizada Cone Beam (TCCB), método que aporta las mayores dosis en la odontología. Esta revisión fue escrita utilizando un enfoque de este tipo con el propósito de racionalizar la dosis de radiación en nuestros pacientes. El equipo del proyecto SEDENTEXCT recopiló y analizó relevantes publicaciones en la literatura, pautas que han demostrado su eficacia en el pasado, para llegar a formular recomendaciones que contribuyan a la optimización del uso de las radiaciones ionizantes en la odontología, ayudando de esa manera a ver con otros ojos la dosis recibida por los pacientes, y con la presente se recomienda tener en cuenta dicho documento para poder prescribir de manera más adecuada los exámenes complementarios que usamos diariamente...

There is now wide acceptance in medicine and dentistry that clinical practice should be as ôevidence-basedõ as possible. Which is why many works have been published aimed at reducing radiation doses in different types of imaging modalities in dentistry, and that the major effect of radiation especially in children requires us to take necessary steps to rationalize their use especially the Cone Beam Computed Tomography (CBCT) method that provides the highest doses in dentistry. This review was written using this approach because of the purpose of streamlining the radiation dose in our patients. SEDENTEXCT team collected and analyzed relevant publications in the literature, guidelines that have proven effective in the past to reach recommendations, which can contribute to optimizing the use of ionizing radiation in dentistry, helping to see with others eyes the dose received by our patients. This paper recommend to consider the SEDENTEXCT project to prescribe more appropriately complementary exams we use daily...

Reliability of measurements on virtual models obtained from scanning of impressions and conventional plaster models

Aim: To evaluate the reliability of linear measurements in virtual models by comparing measurements performed on virtual models obtained from alginate impression scans, plaster model and measurements performed on conventional plaster model. Methods: The sample comprised 26 randomly selected patients to have impressions of their upper and lower jaws taken using alginate and their bite registration using a wax bite. The virtual models were obtained by scanning the alginate impression and the plaster model in a laser surface scanner (R700; 3Shape, Copenhagen, Denmark), and the measurements were performed using the Ortho Analyser (3Shape) proprietary software. The linear measurements of the size of the teeth mesial to distal, arch perimeter, intercanine distance and intermolar distance in the upper and lower arches were performed on plaster models, digital impressions and digital models, by three observers and repeated after 15 days on 8 models for intra-observer evaluations. Data were tabulated and analyzed statistically. Intra-class correlation to check the agreement of intra and inter-observers and ANOVA test were used to analyze the differences between measurements of digital models from impression and digital models from plaster. Results: The results showed a statistically significant difference (pd"0.05) for the posterior teeth, anterior teeth, upper arch perimeter and lower inter-canine distance, comparing the digital models with plaster models, but these differences are considered clinically non-significant. Conclusions: Digital models were proven be reliable and clinically acceptable for measuring tooth width, perimeter arches, intercanine and intermolar distances.

A survey on dental undergraduates' knowledge of oral radiology

Dentists’ incorrect behavior with regards to Oral Radiology, as reported in the literature, has beenrelated to inadequate training of undergraduates. Aim: This study assessed dental undergraduates’knowledge of Oral Radiology. Methods: A questionnaire containing 30 questions pertaining tothree domains - General Principles, Radiobiology/Radioprotection and Technique/Interpretation- was used as data collection instrument. A total of 195 students answered the questionnaires.Results: No statistically significant differences were found between second-, third- and fourthyearstudents (p>0.05) when the whole questionnaire and the General Principles domain (p>0.05)were considered. The Technique/Interpretation domain presented a borderline statistical significancelevel (p=0.051), with more correct answers attributed to second-year students. A statisticallysignificant difference (p<0.05) was seen for the Radiobiology/Radioprotection domain, in whichthe fourth-year students performed better. Conclusions: Dental undergraduates’ knowledge ofOral Radiology did not increase or decrease significantly comparing the undergraduate years.However, with the exception of the Technique/Interpretation domain, students of more advancedundergraduate years answered more correctly the questions. Nevertheless, the Technique/Interpretation domain should be reinforced throughout the undergraduate course.

Diagnosis of invasive cervical resorption by using cone beam computed tomography: report of two cases

A radiographic interpretation is essential to the diagnosis of invasive cervical resorption (ICR) and the difficulty in distinguishing this lesion from internal root resorption has been highlighted in the literature. This paper reports the use of cone beam computed tomography (CBCT) in the diagnosis of ICR. The cases reports describe how CBCT can be used to make a differential diagnosis and also show that the use of this technology can provide relevant information on the location and nature of root resorption, which conventional radiographs cannot. As a result, the root canal treatment was not initially considered. The patients will be monitored and will undergo a scan after a short period of time to detect any small changes. It was observed that both cases benefited from CBCT in the diagnosis of ICR, because this imaging modality determined the real extent of resorption and possible points of communication with the periodontal space.

A interpretação radiográfica é essencial para o diagnóstico da reabsorção cervical invasiva (RCI) e a dificuldade em distingui-la da reabsorção radicular interna tem sido destacada na literatura. Este trabalho relata o uso da tomografia computadorizada de feixe cônico (TCFC) no diagnóstico da RCI. Os casos descrevem como a TCFC pode ser utilizada no diagnóstico diferencial e relatam também como esta tecnologia pode providenciar relevantes informações sobre a localização e natureza das reabsorções radiculares, limitadas pelas radiografias convencionais. Como resultado, o tratamento do canal radicular não foi inicialmente considerado. Os pacientes serão acompanhados e após curto período de tempo novos exames tomográficos serão realizados no intuito de detectar pequenas alterações. Observa-se que ambos os casos beneficiaram-se com o uso da TCFC no diagnóstico de RCI, pois esta modalidade de imagem determinou a real extensão da reabsorção e possíveis pontos de comunicação com o espaço periodontal.

Relação entre a microbiota do canal radicular de dentes humanos permanentes traumatizados com coroa intacta e o teste de percussão vertical / The relation between the microbiota of the root canals in traumatized human permanent teeth with intact crown and the vertical percussion test

O presente estudo teve como objetivos avaliar a microbiota do canal radicular de 20 dentes humanos permanentes traumatizados com coroa intacta e diagnóstico clínico de necrose pulpar e relacionar a resposta ao teste de percussão vertical com a presença de microrganismos nesses dentes. A coleta microbiológica foi realizada com cones de papel absorvente autoclavados e a determinação do número de unidades formadoras de colônias (ufc) de bactérias foi efetuada pela semeadura do material coletado em ágar chocolate (contagem de bactérias totais), ágar mitis salivarius (contagem de estreptococos bucais) e ágar SB20 (contagem de estreptococos do grupo mutans). O Teste de Regressão Linear e Análise de Diagnóstico revelaram que: em apenas 15% das amostras não foi detectado o desenvolvimento microbiano. O tempo decorrido do traumatismo dentário até a intervenção endodôntica variou de 15 dias a 31 meses, sendo que o transcurso desse tempo só foi estatisticamente significante (p = 0,047) em relação ao número de estreptococos bucais isolados no canal radicular. Verificou-se um aumento desse número à medida que o tempo também era maior. O teste de percussão vertical apresentou alta sensibilidade (80%) na detecção de microrganismos no canal radicular de dentes traumatizados. Diante dos resultados, as seguintes conclusões podem ser destacadas: 85% dos dentes apresentaram microrganismos no canal radicular, com coroa intacta; o diagnóstico clínico da necrose pulpar foi realizado, em 70% dos dentes, em até 3 meses e a resposta positiva ao teste de percussão vertical esteve associada à necrose pulpar com presença de microrganismos.

This study aimed to evaluate the microbiota of root canals of 20 human permanent traumatized teeth with crown intact and clinical diagnosis of pulpal necrosis and relate the response to vertical percussion test with the presence of microorganisms in these teeth. The microbiological sampling was performed with autoclaved absorbent paper cones and determining the number of colony-forming units (cfu) of bacteria was performed by seeding the material collected on chocolate Agar (count of total bacteria), mitis salivarius agar (count of buccal streptococcus) and agar SB20 (counts of mutans streptococcus of the group). The Linear Regression test and Diagnostics Analysis revealed that in only 15% of the samples was not detected the microbial development. The time of dental trauma to the endodontic intervention ranged from 15 days to 31 months, with the passage of time only was statistically significant (p = 0.047) on the number of buccal streptococcus isolated in the root canal. There is an increase that number as time was also higher. The vertical percussion test showed high sensitivity (80%) in the detection of microorganisms in root canals of traumatized teeth. Basing on these results we can conclude that: 85% of teeth showed microorganisms in root canal with crown intact, the clinical diagnosis of pulpal necrosis was achieved in 70% of the teeth, up to 3 months and the positive response to the vertical percussion test was associated with pulpal necrosis with the presence of microorganisms.