Marginal gaps and voids using two warm compaction techniques and different sealers: a micro-CT study.

OBJECTIVE: To assess the percentage of marginal gaps and voids in oval-shaped canals obturated by using two warm compaction techniques with a Bio-C sealer and AH Plus Jet. MATERIALS AND METHODS: Forty canines with oval canals were scanned by microcomputed tomography (micro-CT), and root canal preparation was performed with an XP-endo Shaper system and irrigated with 5.25% sodium hypochlorite. Then, the specimens were paired into four groups (n=10) according to the root canal filling technique and endodontic sealer: Bio-C sealer and continuous wave of condensation, Bio-C sealer and Tagger's hybrid, AH Plus Jet and continuous wave of condensation, and AH Plus Jet and Tagger's hybrid. After root canal filling, a new scan was performed. The percentage of marginal gaps and voids was calculated with the ImageJ software, and the data were analyzed statistically using two-way ANOVA and Tukey tests, with a significance level of 5%. RESULTS: The percentage of marginal gaps was significantly lower in the Bio-C sealer than in AH Plus Jet (p=0.021) regardless of the technique. However, no difference was found in the percentage of voids between root canal filling techniques and the endodontic sealer (p>0.05). CONCLUSION: Both sealers and techniques demonstrated good quality of root canal filling. However, the use of the Bio-C sealer enhanced the filling ability by reducing marginal gaps, regardless of the root canal filling technique. CLINICAL RELEVANCE: This study highlights the better performance of the Bio-C sealer in the quality of the root canal filling, reducing marginal gaps when compared to AH Plus Jet independent of the technique.

Endodontic cement penetration after removal of calcium hydroxide dressing using XP-endo finisher.

We aimed to evaluate the penetration of endodontic cement following the removal of calcium hydroxide (Ca(OH)2) dressing using the XP-endo Finisher in association with different irrigating solutions. Sixty premolars were instrumented and applied with a Ca(OH)2 dressing. To remove Ca(OH)2, the teeth were divided into six groups, each with a different volume of sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid (EDTA), as well as solution stirring time with XP-endo Finisher (0, 30, and 60 sec). Root canals were filled using the lateral condensation technique. Fluorescein dye was added to the cement for microscopic laser scanning analysis. In the generated images, linear measurements were taken in micrometers, and their averages were calculated. To analyze the perimeter penetration ratio of the cement, the total perimeter of the canal and the segment of the total perimeter of the canal where the endodontic cement penetrated into the dentinal tubules were measured in micrometers. We found that using an XP-endo Finisher in irrigation was more effective than using a needle and syringe during the extension and penetration of endodontic cement. Shaking with XP-endo Finisher with 17% EDTA increased the extent and perimeter of the penetration of the endodontic cement into the dentinal tubules. However, using the XP-endo Finisher with EDTA only was more efficient than using the instrument interchangeably in NaOCl and EDTA. Although XP-endo Finisher contributes to the removal of Ca(OH)2, none of the protocols or instruments used removed all Ca(OH)2 from the root system.

The thermoplastic techniques or single-cone technique on the quality of root canal filling with tricalcium silicate-based sealer: An integrative review.

Background: The filling of the root canal system (RCS) is an important step in endodontic treatment and aims to obtain a three-dimensional sealing of the root canal spaces to prevent bacterial contamination. For this, the selection of an appropriate sealer must be performed synchronously with the choice of the root canal filling technique. This study aims, through an integrative review, to evaluate the quality of root canal filling by comparing thermoplastic and single-cone (SC) techniques. Material and Methods: The Medline/PubMed, Scopus, Web of Science and Virtual Health Library (VHL) databases were used to find articles published until November 2021. The eligibility criteria comprised articles that evaluating the quality of root canal filling comparing thermoplastic techniques with the SC technique using tricalcium silicate-based sealer. Studies that evaluated primary teeth, endodontic retreatment or perforations, different outcomes, and studies that considered artificial teeth or different sealer and material for obturation of different techniques were excluded. For articles that were not available for access, an additional contact with authors were considered. A total of 1699 articles were found. After duplicate removal, the title and abstract of 828 articles were screened. Sixteen articles were considered for full-text analysis, but only ten articles met the eligibility criteria. Data extracted from the studies were discussed and tabulated to allow the comparison of desired factors. Results: Concerning the formation of gaps/voids, the thermoplastic techniques showed better results than the SC technique in 3 articles. On the other hand, 2 articles reported no statistical difference between the tested techniques. In addition, about the penetration of tricalcium silicate-based sealer in the dentinal tubules, of the 5 articles selected, in 4 there was no significant difference between the tested techniques and only one study showed better penetration of the sealer when using thermoplastic techniques. Conclusions: The thermoplastic technique was better in most selected studies regarding gaps and voids, but regarding the penetration of the sealer into the tubules, both techniques were effective. Key words:Root canal filling, thermoplastic techniques, tricalcium silicate.

Dentinal microcracks induced by endodontic procedures: A scientometric and bibliometric analysis.

Background: Due to the large number of publications relating the occurrence of dental microcracks to endodontic procedures, this bibliometric study evaluated the scientific pattern and trends in literature and provided an overview of scientific production in this context. Aim: To analyze, quantify, and characterize the scientific production and trends of published articles evaluating dentinal microcracks formation after endodontic treatment procedures between 2010 and 2020 using bibliometric indicators. Materials and Methods: Published articles were found by the search in the Medline (PubMed) and Scopus database using the combination of the following keywords: Dentinal crack OR Dentinal Microcrack OR Crack formation OR Dentin Defect AND Endodontic treatment OR Root canal preparation OR Canal Preparation OR Root canal treatment OR endodontic procedures. The search was also conducted in the Journal of Endodontics and International Endodontic Journal. After inclusion and exclusion criteria application, data from all studies included were collected. Results: Among the 556 results after the search, 45 studies were included and analyzed in this bibliometry. No trend was observed in terms of the increasing number of articles over time. Most of them used an in vitro design, compared the effect of different endodontic techniques/systems for root canal instrumentation on dentinal microcracks formation, and were conducted in Turkey, Brazil, and India. Journal of Endodontics and International Endodontic Journal were the main journals with a higher number of articles published. Interestingly, studies conducted with some funding did not lead to higher citation numbers. Moreover, a relevant proportion of studies did not consider the inclusion of control groups, baseline evaluation, or statistical analysis. Micro-CT was the main technique used to evaluate microcrack presence. Conclusion: Microcrack formation after the use of different endodontic techniques/systems has been constantly evaluated in the literature. There is a pattern of methodologies used, which may explain the concentration of these studies in specific journals and countries.

Post-synthetic modification of aluminum trimesate and copper trimesate with TiO2 nanoparticles for photocatalytic applications.

Organic pollutants have been a significant source of concern in recent years due to their facile dissemination and harmful effects. In this work, two different metal-organic frameworks (MOFs) were initially prepared by hydrothermal treatment, namely aluminum trimesate (MIL-100(Al)) and copper trimesate (HKUST-1). These materials were subsequently submitted to a post-synthetic modification step to grow titania nanoparticles on their surface. Anatase nanoparticles with sizes around 5 nm were successfully anchored on MIL-100(Al), and the concentration of TiO2 in this sample was about 68 wt.%. This is the first time that this composite (TiO2@MIL-100(Al)) is reported in the literature. It showed an improved photocatalytic activity, removing 90% of methylene blue (k app = 1.29 h-1), 55% of sodium diclofenac (k app = 0.21 h-1), and 62% of ibuprofen (k app = 0.37 h-1) after four hours of illumination with UV-A light. A significant concentration (14 µM) of reactive oxygen species (ROS) was detected for this composite. HKUST-1 showed a structural collapse during its post-synthetic modification, leading to a non-porous material and providing fewer sites for the heterogeneous nucleation of titania. This behavior led to a low concentration of rutile nanoparticles on HKUST-1 (9 wt.%). However, the obtained composite (TiO2@HKUST) also showed an improved photoactivity compared to HKUST-1, increasing the photodegradation rates evaluated for methylene blue (0.05 h-1 vs. 0.29 h-1), sodium diclofenac (negligible vs. 0.03 h-1), and ibuprofen (0.01 h-1 vs. 0.02 h-1). This work brings new insights concerning the preparation of photocatalysts by growing semiconductor nanoparticles on trimesate-based MOFs.

Endodontic cement penetration after removal of calcium hydroxide dressing using XP-endo finisher

Abstract: We aimed to evaluate the penetration of endodontic cement following the removal of calcium hydroxide (Ca(OH)2) dressing using the XP-endo Finisher in association with different irrigating solutions. Sixty premolars were instrumented and applied with a Ca(OH)2 dressing. To remove Ca(OH)2, the teeth were divided into six groups, each with a different volume of sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid (EDTA), as well as solution stirring time with XP-endo Finisher (0, 30, and 60 sec). Root canals were filled using the lateral condensation technique. Fluorescein dye was added to the cement for microscopic laser scanning analysis. In the generated images, linear measurements were taken in micrometers, and their averages were calculated. To analyze the perimeter penetration ratio of the cement, the total perimeter of the canal and the segment of the total perimeter of the canal where the endodontic cement penetrated into the dentinal tubules were measured in micrometers. We found that using an XP-endo Finisher in irrigation was more effective than using a needle and syringe during the extension and penetration of endodontic cement. Shaking with XP-endo Finisher with 17% EDTA increased the extent and perimeter of the penetration of the endodontic cement into the dentinal tubules. However, using the XP-endo Finisher with EDTA only was more efficient than using the instrument interchangeably in NaOCl and EDTA. Although XP-endo Finisher contributes to the removal of Ca(OH)2, none of the protocols or instruments used removed all Ca(OH)2 from the root system.

Push-out bond strength and marginal adaptation of apical plugs with bioactive endodontic cements in simulated immature teeth.

OBJECTIVES: This study evaluates the bond strength and marginal adaptation of mineral trioxide aggregate (MTA) Repair HP and Biodentine used as apical plugs; MTA was used as reference material for comparison. MATERIALS AND METHODS: A total of 30 single-rooted teeth with standardized, artificially created open apices were randomly divided into 3 groups (n = 10 per group), according to the material used to form 6-mm-thick apical plugs: group 1 (MTA Repair HP); group 2 (Biodentine); and group 3 (white MTA). Subsequently, the specimens were transversely sectioned to obtain 2 (cervical and apical) 2.5-mm-thick slices per root. Epoxy resin replicas were observed under a scanning electron microscope to measure the gap size at the material/dentin interface (the largest and smaller gaps were recorded for each replica). The bond strength of the investigated materials to dentin was determined using the push-out test. The variable bond strengths and gap sizes were evaluated independently at the apical and cervical root dentin slices. Data were analyzed using descriptive and analytic statistics. RESULTS: The comparison between the groups regarding the variables' bond strengths and gap sizes showed no statistical difference (p > 0.05) except for a single difference in the smallest gap at the cervical root dentin slice, which was higher in group 3 than in group 1 (p < 0.05). CONCLUSIONS: The bond strength and marginal adaptation to root canal walls of MTA HP and Biodentine cement were comparable to white MTA.

Dentes gretados: o que clínicos e especialistas precisam saber / Cracked teeth: What clinicians and specialists need to know

A proposta da presente revisão de literatura foi estabelecer as evidências existentes sobre etiologia, sinais e sintomas, métodos de diagnóstico e tratamento de dentes gretados. Segundo a American Association of Endodontists (AAE), o termo dente gretado (DG) foi definido como uma fratura em um plano que quebra a continuidade do esmalte e da dentina, sem separação das partes, geralmente no sentido mesiodistal, passando pela superfície oclusal, podendo envolver uma ou ambas as cristas marginais. Essa fratura, por apresentar profundidade e direção desconhecidas, pode se estender até a polpa e/ou ligamento periodontal, levando a um quadro de pulpite reversível, pulpite irreversível, necrose pulpar ou, até mesmo, evoluir para uma fratura completa. Atualmente, os DGs estão relacionados à terceira maior causa de dentes perdidos, após cárie e doença periodontal. Estudos indicam uma falta de consenso entre profissionais sobre como tratar dentes gretados, uma questão clínica relevante, que precisa ser priorizada e esclarecida. Nesse contexto, essa revisão abordou a etiologia, sinais e sintomas, métodos de diagnósti- co e tratamento de dentes gretados (AU)

The purpose of this literature review is to examine the existing evidence regarding etiology, signs, symptoms, methods of diagnosis, and treatment of cracked teeth. According to the American Association of Endodontists (AAE), the term cracked tooth (CT) is defined as "a fracture in a plane that breaks the continuity of the enamel and dentin, without separation of the parts, usually in the mesiodistal direction, passing through the surface occlusal, which may involve one or both of the marginal ridges." Due to its unknown depth and direction, this fracture can extend to the pulp and periodontal ligament, leading to reversible pulpitis, irreversible pulpitis, pulp necrosis, or even progress to a complete fracture. Currently, cracked teeth are related to the third largest cause of missing teeth, after caries and periodontal disease. Studies indicate a lack of consensus among professionals about treating cracked teeth, a clinically relevant issue that needs to be prioritized and clarified. In this context, this review addressed the etiology, signs and symptoms, diagnostic methods, and treatment of cracked teeth (AU).

Hospital transfusion service operations during the SARS-CoV-2 pandemic: Lessons learned from the AABB hospital survey in preparation for the next infectious disease outbreak.

BACKGROUND: The SARS-CoV-2 pandemic disrupted hospital operations, affected the blood supply, and challenged the health care system to develop new therapeutic options, including convalescent plasma (CCP). The aim of this study is to describe and analyze blood supply fluctuations and the use of convalescent plasma in 2020. METHODS: AABB distributed a weekly and biweekly questionnaire through email to hospital-based members (HBM). RESULTS: The survey was sent to 887 HBM with 479 unique respondents, most of the hospitals served pediatric and adult patients, and all states of the country participated, except Idaho and Vermont. Fifty four percent of HBM reported increased wastage in the early phase of the pandemic (May), which decreased to 4% by the end of June and throughout the rest of the year. The majority of HBM reported receiving alerts from their blood suppliers reporting blood shortages throughout the year. During March and April, only 12% of HBM were performing elective surgical procedures. The top reasons to delay procedures were: bed availability (28%); COVID-19 caseload (23%; and blood availability (19%). By mid-April, 42% HBM had transfused CCP and reported >24 h delay in getting the units; the vast majority obtained CCP using the Expanded Access Protocol, and later, the Emergency Use Authorization. HBM consistently prioritized the most severe patients to receive CCP, but the proportion of severely ill recipients fell from 52% to 37% between May and October, with an increase from 5% to 21% of HBM providing CCP transfusion early in the course of the disease. DISCUSSION: Blood utilization and availability fluctuated during the pandemic. The fluctuations appeared to be related to the number of COVID-19 in the community. The use and regulatory landscape of CCP rapidly evolved over the first 8 months of the pandemic.

Tratamento endodôntico de incisivo central inferior permanente com dilaceração radicular incomum, após trauma no predecessor decíduo: relato de caso / Endodontic treatment of mandibular central incisor with unusual root dilaceration, following trauma to the deciduous predecessor: case report

Introdução: Alterações morfológicas na cavidade pulpar e na anatomia radicular podem constituir um desafio ao tratamento endodôntico. A dilaceração pode ser resultado de trauma na dentição decídua, na época da formação das raízes, provocando acentuada curvatura da raiz ou da coroa em um dente permanente. Objetivo: O presente relato de caso teve por objetivo descrever o tratamento endodôntico de um dente #41 com acentuada dilaceração radicular. Radiograficamente, a região periapical do dente #41 mostrou extensa área radiolúcida, sugestiva de osteólise periapical em decorrência de necrose pulpar, que foi confirmada pela ausência de resposta aos testes pulpares. O tratamento endodôntico foi realizado. Conclusão: Após 90 meses de acompanhamento, constatou-se ausência de sinais ou sintomas, e o exame radiográfico forneceu evidências de cicatrização óssea periapical (AU).

Introduction: The morphological changes in the pulp cavity and root anatomy can lead to difficulties in carrying out endodontic treatment. Dilaceration can be the result of trauma in primary dentition, in the root formation phase, provoking accentuated root or crown curvature in a permanent tooth. Objective: The present case report aimed to describe the endodontic treatment of tooth 41 with accentuated root laceration. Radiographically, the periapical region of tooth #41 showed an extensive radiolucent area, suggestive of periapical osteolysis due to pulp necrosis, which was confirmed by the lack of response and pulp tests. Endodontic treatment was realized. Conclusion: The follow-up at 90 months showed no signs or symptoms, and the radiographic examination provided evidence of periapical bone healing.

Composite vignettes of former Brazilian high-performance volleyball athletes' perspective on life skills learning and transfer.

The purpose of this study was to examine former Brazilian high-performance volleyball athletes' perspectives on life skills learning and transfer through their experiences in sport. This qualitative study involved a narrative approach through composite vignettes. The creation of the composite vignettes included the most relevant life events and participants' perspectives through their accounts of the experience transformed in one unique voice. Participants were five former Brazilian high-performance volleyball athletes. Data were collected through rappaport timeline and semi-structured interviews. Findings showed athletes were able to learn and transfer life skills throughout their careers and later in life through an implicit approach to life skills development and transfer. The trials and tribulations of high-performance sport were, in these cases, used as life lessons that transformed into life skills used in athletes' lives beyond sport. Moving forward, more research is needed to understand the high-performance sport's role in life skills transfer and its implication for athletes' development across socio-cultural contexts.

Gamma sterilization of collagen/hydroxyapatite composites: Validation and radiation effects.

In this work, gamma sterilization was validated, and the impact of this sterilization process on collagen/hydroxyapatite (Col/HAp) composites was investigated. It has been already recognized that the improper sterilization of healthcare products may lead to infection and mortality/morbidity issues in patients. Gamma sterilization has emerged as a promising sterilization method because it shows advantages such as low cost, a small increase in temperature of irradiated materials, and no production of toxic residues. Moreover, gamma rays can reach the products even when contained in sealed packages. The dose of gamma radiation applied in this study ranged from 17.5 to 50 kGy. The studied samples were examined by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetry (TG), and differential scanning calorimetry (DSC). No apparent effect of gamma radiation on HAp was observed even when doses as high as 50 kGy were applied. On the other hand, Col was greatly affected by gamma radiation, displaying cross-linking and degradation after sterilization. These structural changes may alter Col's properties, which could, in turn, impact its medical use. As a consequence, it is strongly recommended that the irradiation dose used to sterilize the Col/HAp composites shall be kept as low as possible to mitigate the structural changes induced in Col. It was noticed that a radiation dose of 17.5 kGy was sufficient to sterilize the examined samples because a sterility assurance level (SAL) below 10-6 was detected. Although dramatic structural changes were observed in Col when this dose was applied, the sterilized samples showed no toxicity to human mesenchymal stem cells. Based on these results, we established a VDMax of 17.5 kGy for Col/HAp-based healthcare products.

Micro-CT evaluation of maxillary first molars: interorifice distances and internal anatomy of the mesiobuccal root.

This study aimed to describe the morphometric relationship of root canal orifices on the pulp floor in the presence/absence of mesiobuccal second canal (MB2) in the maxillary first molars and other aspects of its internal anatomy. Sixty-two maxillary first molars were scanned by micro-CT. The presence of the MB2 canal was verified. The distance between the center points of the MB1, MB2, distobuccal (DB), and palatal (P) canal orifices on the pulp floor were measured (MB1-MB2, MB1-DB, MB2-DB, MB1-P, and DB-P). The MB1-P to DB-P ratio was calculated. The distances between the anatomic apex and the MB1 and MB2 apical foramina were measured. The length of the band-shaped isthmus was also measured. Student's t-test was applied to verify the association between the presence of an MB2 canal, the interorifice distances, and the ratio of the MB1-P to DB-P distance (α = 5%). The MB2 canal was present in 43 roots (69.35%). Statistics showed significant differences when MB2 was present for the largest MB1-P distance (p < 0.05) and higher values for the MB1-P to DB-P ratio (p < 0.05). A band-shaped isthmus was detected in 25.8% of MB roots. The mean distance from the apical foramen to the isthmus floor ranged from 1.74 for MB1 canals to 1.42 for MB2 canals. Canal orifice distances on the pulp floor may predict the presence of MB2 canals. There was a high incidence of isthmus, accessory canals, and apical delta in the critical apical zone in MB roots of maxillary first molars.

Bio-C Repair - A New Bioceramic Material for Root Perforation Management: Two Case Reports.

These case reports aimed to describe the management of lateral perforation in the middle cervical third of the root in two maxillary incisors with pulp canal calcification using Bio-C Repair, with safe and viable clinical treatment strategies. Digital radiographic exams were obtained with different angles and analyzed using different filters. Cone-beam computed tomography (CBCT) images were requested to show the actual position of the canal, location of the perforation, and guide the strategic planning of the case. Subsequently, cavity access was prepared with the aid of dental operating microscopy. After perforation was identified, granulation tissue was removed and the original canal was identified and then dressed with calcium hydroxide. In the second visit, the perforation was filled with Bio-C Repair and the canal system filled with gutta-percha points and a root canal sealer (Bio-C Sealer). The teeth were restored with glass fiber post, 4 mm beyond the perforation level, and provisory crowns. Both teeth treated as described above were functional and asymptomatic with a 1-year clinical and radiographic assessment. The Bio-C Repair is suggested as a new cement option for the management of lateral canal perforations, with effective results as observed after a one-year follow-up.

Dentinal Microcracks Induced by Endodontic Procedures: Suggested Design for Experimental Studies Using Micro-Computed Tomography and Strain Gauges.

INTRODUCTION: The present study aimed to describe an in vitro study model to investigate root surface strain (RSS) and its correlation with the initiation/propagation of microcracks during different endodontic procedures. METHODS: Four lower human incisors extracted microcrack free were selected by micro-computed tomographic imaging. Two strain gauges were bonded to the root surface of each incisor. Then, the teeth were prepared to reproduce the periodontal ligament artificially. The gauges were attached to a data acquisition system. The RSS was recorded during the entire endodontic procedure, which consisted of accessing the endodontic cavity, cleaning, shaping preparation with an Mtwo rotary system (VDW, Munich, Germany), and filling with a standardized technique. Each incisor was submitted to a different retreatment protocol and supplementary cleaning method as follows: (1) Reciproc (RC, VDW) + Flatsonic (FS; Helse, Santa Rosa de Viterbo, Brazil), (2) RC + XP-endo Finisher (XPF; FKG Dentaire, La Chaux-de-Fonds, Switzerland), (3) Mtwo retreatment (MR) + FS, and (4) MR + XPF. Finally, the teeth were rescanned to establish the postoperative microcrack formation by 2 well-trained and blinded examiners. RESULTS: The maximum and minimum RSS values were -120 and 510 microstrains, respectively, for all of the files. RC showed the highest RSS values during endodontic retreatment compared with MR. FS demonstrated a higher variation between the minimum and maximum RSS than XPF. No microcracks were observed in the specimens. CONCLUSIONS: This preliminary study proposed an experimental model that would combine 2 methods to evaluate the effects of endodontic systems on dentin. Although strain gauges would provide data on the stresses created, the pre- and postoperative evaluation of micro-computed tomographic images would enable microcrack formation to be determined.

Root canal shaping of curved canals by Reciproc Blue system and Pro Taper Gold: A micro-computed tomographic study.

BACKGROUND: This study aimed to evaluate the centralization and transportation of ProTaper Gold (PTG) rotary system and Reciproc Blue (RB) reciprocating system in curved canals, by using micro-CT. MATERIAL AND METHODS: Twenty extracted mandibular molars were previously scanned by using the SkyScan 1174 microtomograph to select the Vertucci IV anatomic type. The specimens were divided into two groups (n=10) according to the mechanized system used to prepare the root canals. The teeth were scanned by micro-CT to calculate the increase volume, percentage of dentin removed, remaining dentin thickness, structure model index (SMI), degree of transportation and centering ability of root canals. The Student's t test was used to evaluate differences between PTG and RB in each measurement evaluated. RESULTS: No significant differences were found between the groups in the increase of the total root canal and apical volume; percentage of dentin removed after preparation; SMI of the mesiolingual canal; degree of transportation of the canal and centering ability of the cervical and middle thirds (P>0.05). There were significant differences in the mesiobuccal canal in SMI and in the centering ability of the apical third (P<0.05). Concerning the remaining dentin thickness, there was also no significant diferences between the groups, except for some regions were RB was observed to have a superior cutting capacity (P<0.05). CONCLUSIONS: Both systems were efficient and safe for performing preparation of the moderately curved root canals of mandibular molars. RB instruments produced more circular and better centralized canals in the apical third of the mesiobuccal canal, with superior cutting action when compared with PTG instruments. Key words:Nickel-titanium instrument, heat treatment, micro-computed tomography, canal transportation.

Bio-c repair - a new bioceramic material for root perforation management: two case reports

Abstract These case reports aimed to describe the management of lateral perforation in the middle cervical third of the root in two maxillary incisors with pulp canal calcification using Bio-C Repair, with safe and viable clinical treatment strategies. Digital radiographic exams were obtained with different angles and analyzed using different filters. Cone-beam computed tomography (CBCT) images were requested to show the actual position of the canal, location of the perforation, and guide the strategic planning of the case. Subsequently, cavity access was prepared with the aid of dental operating microscopy. After perforation was identified, granulation tissue was removed and the original canal was identified and then dressed with calcium hydroxide. In the second visit, the perforation was filled with Bio-C Repair and the canal system filled with gutta-percha points and a root canal sealer (Bio-C Sealer). The teeth were restored with glass fiber post, 4 mm beyond the perforation level, and provisory crowns. Both teeth treated as described above were functional and asymptomatic with a 1-year clinical and radiographic assessment. The Bio-C Repair is suggested as a new cement option for the management of lateral canal perforations, with effective results as observed after a one-year follow-up.

Resumo O presente relato de caso teve como objetivo descrever o manejo da perfuração lateral no terço médio cervical da raiz em dois incisivos superiores com calcificação pulpar utilizando o Bio-C Repair, com estratégias de tratamento clínico seguras e viáveis. Radiografias digitais foram obtidas em diferentes ângulos e analisadas com diferentes filtros. Imagens de tomografia computadorizada de feixe cônico (TCFC) foram solicitadas para mostrar a real posição do canal e a localização da perfuração, e orientar o planejamento estratégico do caso. Posteriormente, o acesso à cavidade foi preparado com auxílio de microscopia cirúrgica. Após a identificação da perfuração, o tecido de granulação foi removido, o canal original foi identificado e, em seguida, recebeu medicação intracanal à base de hidróxido de cálcio. Na segunda visita, a perfuração foi selada com Bio-C Repair e o sistema de canais obturado com cones de guta-percha e cimento endodôntico (Bio-C Sealer). Os dentes foram restaurados com pino de fibra de vidro, 4 mm além do nível da perfuração, e coroas provisórias. Ambos os dentes tratados conforme descrito acima se mostraram funcionais e assintomáticos na avaliação clínica e radiográfica de 1 ano. O Bio-C Repair é sugerido como uma nova opção de cimento endodôntico para o manejo de perfurações laterais, com resultados efetivos observados após um ano de acompanhamento.

Strain-inducing photochemical chlorination of graphene nanoribbons on SiC (0001).

As different low-dimensional materials are sought to be incorporated into microelectronic devices, graphene integration is dependent on the development of band gap opening strategies. Amidst the different methods currently investigated, application of strain and use of electronic quantum confinement have shown promising results. In the present work, epitaxial graphene nanoribbons (GNR), formed by surface graphitization of SiC (0001) on crystalline step edges, were submitted to photochemical chlorination. The incorporation of Cl into the buffer layer underlying graphene increased the compressive uniaxial strain in the ribbons. Such method is a promising tool for tuning the band gap of GNRs.

Micro-CT evaluation of maxillary first molars: interorifice distances and internal anatomy of the mesiobuccal root

Abstract: This study aimed to describe the morphometric relationship of root canal orifices on the pulp floor in the presence/absence of mesiobuccal second canal (MB2) in the maxillary first molars and other aspects of its internal anatomy. Sixty-two maxillary first molars were scanned by micro-CT. The presence of the MB2 canal was verified. The distance between the center points of the MB1, MB2, distobuccal (DB), and palatal (P) canal orifices on the pulp floor were measured (MB1-MB2, MB1-DB, MB2-DB, MB1-P, and DB-P). The MB1-P to DB-P ratio was calculated. The distances between the anatomic apex and the MB1 and MB2 apical foramina were measured. The length of the band-shaped isthmus was also measured. Student's t-test was applied to verify the association between the presence of an MB2 canal, the interorifice distances, and the ratio of the MB1-P to DB-P distance (α = 5%). The MB2 canal was present in 43 roots (69.35%). Statistics showed significant differences when MB2 was present for the largest MB1-P distance (p < 0.05) and higher values for the MB1-P to DB-P ratio (p < 0.05). A band-shaped isthmus was detected in 25.8% of MB roots. The mean distance from the apical foramen to the isthmus floor ranged from 1.74 for MB1 canals to 1.42 for MB2 canals. Canal orifice distances on the pulp floor may predict the presence of MB2 canals. There was a high incidence of isthmus, accessory canals, and apical delta in the critical apical zone in MB roots of maxillary first molars.

Tratamento endodôntico de segundo molar inferior com presença de canal mesiomediano: relato de caso / Endodontic treatment of second mandibular molar with presence of middle mesial canal: case report

Introdução: A identificação de possíveis variações anatômicas é decisiva para o correto diagnóstico e planejamento da terapia endodôntica. Objetivo: Relatar o tratamento endodôntico de um dente #37, no qual foi identificado um terceiro canal na raiz mesial (canal mesio-mediano, CMM). Caso clínico: Dente #37 com diagnóstico de pulpite irreversível sintomática, foi encaminhado para realizar tratamento endodôntico. Durante o acesso coronário, e com auxílio de microscópio operatório (MO), foram identificadas trincas coronárias. Foi solicitada uma tomografia computadorizada de feixe cônico (TCFC), a partir da qual foi descartada a presença de trinca radicular. A TCFC possibilitou, também, identificar a presença de um terceiro canal na raiz mesial, localizado entre os canais mesiovestibular e mesiolingual. O tratamento endodôntico foi executado pelo sistema reciprocante WaveOne GOLD. A solução irrigadora de escolha para o preparo químico-mecânico foi o hipoclorito de sódio a 5,25%. Imediatamente antes da obturação, os canais foram irrigados com EDTA a 17%, para auxiliar na remoção da smear layer e, em seguida, foi realizada nova irrigação com hipoclorito de sódio a 5,25%. Os canais foram secos com pontas de papel absorvente e obturados pela técnica de onda contínua de condensação. Resultados: Os canais radiculares do dente #37 foram devidamente instrumentados e obturados. A paciente não apresentou qualquer sintomatologia pós-operatória, sendo encaminhada para a reabilitação protética final. Conclusão: A TCFC e o microscópio operatório foram decisivos para o correto planejamento do caso, tanto em relação à trinca observa- da quanto à detecção do canal mesiomediano (AU).

Introduction: Identification of possible anatomical variations is crucial for the correct diagnosis and planning of endodontic therapy. Objective: To report the endodontic treatment of tooth #37, in which a third canal was located in the mesial root (middle mesial canal - MMC). Methods: Tooth #37 was diagnosed with symptomatic irreversible pulpitis and referred for endodontic treatment. Coronary cracks were found during coronal access using a dental operating microscope (DOM). A cone-beam computed tomography (CBCT) was requested. CBCT revealed cracks involving the pulp chamber floor and a third root canal in the mesial root, between the mesiobuccal and the mesiolingual canals. Endodontic treatment was performed with the WaveOne GOLD reciprocating system. The chemical-mechanical preparation was performed with 5.25% sodium hypochlorite and 17% EDTA to remove the smear layer, followed by another irrigation with sodium hypochlorite. The canals were dried with absorbent paper points. The root canal obturation was performed with the continuous wave of condensation technique. Results: The root canals of tooth #37 were correctly instrumented and obturated. The patient did not present with any postoperative symptoms, and was referred for final prosthetic rehabilitation. Conclusion: CBCT and DOM were paramount for the correct planning of the case, as regards the presence of cracks and the detection of the middle mesial canal (AU).