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.

Micro-computed tomographic assessment of the variability and morphological features of root canal system and their ramifications

Abstract Objectives This study assessed the incidence and variability features of root canals system (RCS) and their ramifications according to Pucci & Reig (PR) (1944) and the American Association of Endodontists (AAE) (2017) by micro-computed tomography (μCT). Methodology 500 representative extracted human teeth of each tooth group (n=50) (maxillary/mandibular central and lateral incisors, canines, first and second premolars and molars) were scanned by μCT with a resolution of 26.70 μm. The reconstructed cross-sections images and the visualization of the continuous slices in the transversal axis were performed using DataViewer software. RCS were classified according to Pucci & Reig (main canal, collateral canal, lateral canal, secondary canal, accessory canal, intercanal, recurrent canal) and AAE (main canal, accessory canal, lateral canal). The apical deltas were assessed for both classifications. The prevalence of apical deltas was evaluated using the Chi-squared test (p<0.05). Results According to PR, a higher incidence of lateral canals was observed in maxillary canines (10%), central incisors (8%) and first premolars (6%). Using AAE, the highest incidence of lateral canals was observed in the mandibular first premolars (85%), first and second molars (84%), lateral incisors (67%), canines (59%), and in maxillary first premolars (52%). Regarding accessory canals, the PR showed a frequency in 2% of the maxillary lateral incisors and maxillary and mandibular first premolars and 3% of mandibular first and second molars. On the other hand, the AAE showed the highest incidence of accessory canals in 86% of the maxillary first premolars, 71% in mandibular lateral incisors, 69% in mandibular first premolars, 65% in mandibular canines, and 56% in maxillary canines. The PR showed the lowest incidence of apical deltas for all dental groups when compared with AAE (p=0.004). Interestingly, distal canals in maxillary molars showed a significant discrepancy between classifications (p=0.027). Conclusions μCT enabled accurately describing the RC system and related ramifications, adding to the PR and AAE classifications, with some discrepancies reported for maxillary molars. Clinical Relevance This μCT study enabled a thorough description of the variability among root canals and their ramifications, including clinically relevant details on the presence and location of lateral canals and accessories in all human tooth groups, beyond the currently existing classification systems.

A micro-CT evaluation of the performance of rotary and reciprocating single-file systems in shaping ability of curved root canals

Abstract To compare the shaping ability of different single-file systems in the preparation of mesial curved canals of mandibular molars using micro-CT technology. Fifteen mesial roots of mandibular molars with two independent and curved canals (n = 30) were selected, scanned at a resolution of 26.7 μm anatomically matched, and distributed into three groups (n = 10), according to the preparation system: WaveOne 25.08, Reciproc 25.08, and OneShape 25.06. A final micro-CT scanning was performed, data sets were registered with their respective counterparts, and compared regarding the three-dimensional (volume, surface area, and structure model index - SMI) and two-dimensional (perimeter, area, roundness, major and minor diameters) parameters, as well as, canal transportation, using ANOVA and post hoc Tukey tests (α = 5%). Overall, no difference was observed between groups regarding area, perimeter, volume, surface area, and canal transportation (p > 0.05). Within group, no canal transportation was significantly higherobserved in the apical third (0.10 ± 0.05 mm) compared to coronal (0.08±0.040 mm) and middle (0.07 ± 0.03 mm) thirds (p < 0.05). Structure model index (SMI) was statistically higher after preparation with OneShape instrument (0.36 ± 0.26) compared to other systems (p < 0.05). Within the parameters of this study, similar shaping ability was observed in the preparation of mesial curved root canals of mandibular molars with Reciproc, OneShape and WaveOne systems.

Root canal preparation using micro-computed tomography analysis: a literature review

Abstract: This literature review has critically analyzed the published research related to the biomechanical preparation of root canals with three-dimensional analysis using micro-computed tomography (micro-CT). In December 2017, six databases (PubMed, Cochrane, Web of Science, Embase, Scopus, and Science Direct) were accessed using keywords to find articles including the use of the micro-CT analysis in biomechanical root canal preparation. There were 60 full articles that were selected, which were screened and read by two authors. The research that was reviewed and analyzed included root canal anatomy and sample selection, changes in canal shape and untouched canal areas, canal transportation and centering ability, and kinematics (motion). Of the studies selected, 49.18% discussed anatomical characteristics, with 54.1% of these studies describing mesial roots of mandibular molars with moderate curvature. Only 35% used a stratified distribution based on root canal system morphology and quantitative data obtained by micro-CT. The analysis of canal transportation and centering ability showed that transport values in the apical third exceeded the critical limit of 0.3 mm in mesial roots of mandibular molars with moderate curvature, especially in the groups in which a reciprocating system was used. In relation to kinematics, 91.70% of the reviewed studies evaluated continuous rotating instruments, followed by reciprocating rotation (38.33%), vibratory (15%), and the adaptive kinematics, which was in only 8.33%. The reciprocating kinematics was associated with higher canal decentralization and transportation indexes, as well as a greater capacity for dentin removal and debris accumulation. This literature review showed that the anatomy, the type of design and kinematics of instruments, and the experimental design are factors that directly influence the quality of biomechanical preparation of root canals analyzed in a qualitative and quantitative manner by micro-CT.

Sella landmark variability and its effect on the Angles SNA and SNB: a comparative study / Variabilidade do ponto Sela e seu efeito em ângulos SNA e SNB: um estudo comparativo

ABSTRACT Objective: To determine intra- and inter-observer precision in Sella (S), Nasion (N), point A and B identification. Additionally, to determine how it can interfere with angular measurements of SNA and SNB by orthodontists and dentomaxillofacial radiologists. Methods: Twenty digital lateral cephalometric radiographs were evaluated by five orthodontists and five dentomaxillofacial radiologists. Results: Differences in linear and angular measuremts were assessed. Intra- and inter-observer agreement was evaluated. Intra- and inter-observer reproducibility of the horizontal and vertical components of the S landmark identification (ICC: 0.75/0.90). Orthodontists tended to produce larger SNA (-0.18º), while SNB angle had a tendency to be smaller (0.55º). In general, SNA angle was smaller (DMFRs: -0.308º and orthodontists: -0.092º), and SNB presented with larger values (DMFR: 0.078º and orthodontists: -0.074º). Conclusion: Identification of the Sella landmark revealed a better agreement amongst dentomaxillofacial radiologists. Orthodontists, however, showed a larger variability in S identification and, consequently, the SNA and SNB angles drifted significantly.

RESUMO Objetivo: Determinar a precisão intra e inter-observador na identificação dos pontos Sella (S), Násio (N), A e B. Também, verificar como a identificação dos pontos pode interferir nas medições angulares de SNA e SNB por ortodontistas e radiologistas odontológicos. Métodos: Vinte telerradiografias laterais digitais foram avaliadas por cinco ortodontistas e cinco radiologistas odontológicos. Diferenças de medidas lineares e angulares foram avaliadas. Resultados: Concordância intra e inter-observador foi avaliada e a reprodutibilidade intra e inter-observador dos componentes horizontais e verticais da identificação S marco (ICC: 0,75 / 0,90). Ortodontistas tenderam a produzir maior valor para SNA (-0.18º), enquanto que para o ângulo SNB houve tendência a dimininuição do valor (0.55º). Em geral, os valores obtidos para o ângulo SNA foram menores (radiologistas: -0.308º e ortodontistas: -0.092º) e SNB apresentados com valores maiores (radiologistas: -0.074º: 0.078º e ortodontistas). Concordância intra e inter-observador foi avaliada e a reprodutibilidade intra e inter-observador dos componentes horizontais e verticais da identificação S marco (ICC: 0,75 / 0,90). Ortodontistas tenderam a produzir maior valor para SNA (-0.18º), enquanto que para o ângulo SNB houve tendência a dimininuição do valor (0.55º). Em geral, os valores obtidos para o ângulo SNA foram menores (radiologistas: -0.308º e ortodontistas: -0.092º) e SNB apresentados com valores maiores (radiologistas: -0.074º: 0.078º e ortodontistas). Conclusão: A identificação do ponto Sella revelou uma melhor concordância entre os radiologistas odontológicos. Ortodontistas, no entanto, mostraram uma maior variabilidade na identificação do ponto S e, consequentemente, os ângulos SNA e SNB variaram significativamente. A identificação do ponto Sella revelou uma melhor concordância entre os radiologistas odontológicos. Ortodontistas, no entanto, mostraram uma maior variabilidade na identificação do ponto S e, consequentemente, os ângulos SNA e SNB variaram significativamente.

Clinical diagnosis of hyposalivation in hospitalized patients

OBJECTIVE: The aim of this study was to evaluate the effectiveness of clinical criteria for the diagnosis of hyposalivation in hospitalized patients. MATERIAL AND METHODS: A clinical study was carried out on 145 subjects (48 males; 97 females; aged 20 to 90 years). Each subject was clinically examined, in the morning and in the afternoon, along 1 day. A focused anamnesis allowed identifying symptoms of hyposalivation, like xerostomia complaints (considered as a reference symptom), chewing difficulty, dysphagia and increased frequency of liquid intake. Afterwards, dryness of the mucosa of the cheecks and floor of the mouth, as well as salivary secretion during parotid gland stimulation were assessed during oral examination. RESULTS: Results obtained with Chi-square tests showed that 71 patients (48.9%) presented xerostomia complaints, with a significant correlation with all hyposalivation symptoms (p <0.05). Furthermore, xerostomia was also significantly correlated with all data obtained during oral examination in both periods of evaluation (p<0.05). CONCLUSION: Clinical diagnosis of hyposalivation in hospitalized patients is feasible and can provide an immediate and appropriate therapy avoiding further problems and improving their quality of life.

Virtual autopsy in forensic sciences and its applications in the forensic odontology / A autópsia virtual nas ciências forenses e sua aplicação na Odontologia forense

Nowadays, technological advances are becoming more and more important in forensic sciences. Yet autopsy is still one of the very traditional methods. This also applies for dentalautopsies, in which visual, photographic and radiological evidences are collected. In this context, Virtual Autopsy appears as a helpful and complementary tool for dental and medical cadaveric examination. Usinghigh-tech radiological approaches, Virtual Autopsy may provide, through images, an efficient and more accurate view on the individual case. This critical review aims to update the dental professionalspresenting the first national paper with explanations on Virtual Autopsy.

Atualmente os avanços tecnológicos se fazem cada vez mais importantes nas ciências forenses. Por outro lado a autópsia ainda é uma abordagem tradicional na prática médica-odontológica, na qual evidências são coletadas por meio fotográfico e radiológico. Neste contexto, a Autópsia Virtual surge como uma ferramenta útil e complementar para o exame cadavérico. Através da alta tecnologia radiológica a Autópsia Virtual fornece uma visão eficiente e precisa do caso a ser analisado. Esta revisão crítica tem o objetivo de atualizar os Cirurgiões-dentistas apresentando o primeiro trabalho com o conteúdo voltado a Autópsia Virtual.