Analysis of palatal marginal alveolar exostosis and palatal torus using cone-beam computed tomography.

The aim of the present study was to analyze palatal marginal alveolar exostosis (PMAE) and palatal torus (PT). Cone-beam computed tomography (CBCT) of the maxilla in multiplanar sections and volumetric renderings were used to assess this. PT and PMAE were classified according to location and morphology. Height, width, length, and thickness of the overlying mucosa were determined. The prevalence of PT and PMAE was assessed according to sex and age group. The correlation between the occurrence of PMAE and PT was also evaluated. A total of 385 CBCT scans were examined. PT was found in 38.70% of the sample and located more frequently in the middle third of the maxilla (52.35%) with a flat shape (42.95%). PMAE was found in 54.80% of the sample, bilaterally in 56.40% of the cases, and located more frequently in the molar region (62.42%) in the form of small nodules (36.97%). The mucosa covering PMAE was generally thicker than that over PT. The use of CBCT for the identification of PT and PMAE in vivo showed high frequencies of both conditions. The occurrence of PMAE was independent of the presence of PT.

Intrusion of overerupted periodontally compromised posterior teeth using orthodontic mini implants: A mechanobiological finite element study.

INTRODUCTION: The intrusion of posterior teeth had been considered challenging up to the development of orthodontic mini implants. In periodontally compromised teeth, the challenge is even greater, because of the root resorption risk due to periodontal ligament over-compression. Still, the precise strategy to determine the force reduction level remains uncertain. OBJECTIVE: The objective of the study was to determine, by a finite element analysis (FEA), the force reduction needed to avoid root resorption and maintain the efficiency of orthodontic mechanics of periodontally compromised teeth similar to the sound one. METHODS: An anatomical model was constructed representing a premolar inserted into a maxillary bone. Based on the initial model (R0), three bone height loss conditions were simulated (R2 = 2 mm, R4 = 4 mm, and R6 = 6 mm). Two intrusive movements were simulated: pure intrusion (bilateral mini implant) and uncontrolled-tipping intrusion (buccal mini implant). The hydrostatic stress at the periodontal ligament was used to evaluate the risk of root resorption due to over-compression. RESULTS: For bilateral mini implant intrusion, the force had to be decreased by 16%, 32% and 48% for R2, R4 and R6, respectively. For buccal mini implant intrusion, the required reductions were higher (20%, 36% and 56%). A linear relationship between the intrusive force reduction and the alveolar bone height loss was observed in both intrusion mechanics. CONCLUSIONS: According to the FE results, 8% or 9.3% of force reduction for each millimetre of bone height loss is suggested for intrusion with bilateral or buccal mini implant, respectively. The buccal mini implant anchorage must be associated with a supplemental strategy to avoid buccal crown tipping.

Three dimensionally printed surgical guides for removing fixation screws from onlay bone grafts in flapless implant surgeries.

The present technique report describes a digital workflow for flapless implant surgery after onlay block bone graft healing in the esthetic area. Virtual removal of block fixation screws and optimal single-tooth implant position and digital crown waxing were planned from cone beam computed tomography (CBCT) and intraoral scans. Two different surgical guides were digitally designed and 3D-printed to allow for flapless implant surgery. The first surgical guide was used to remove all 3 fixation screws from a healed onlay block graft, whereas the second guide was used to determine the implant position and direction. The present methodology may be considered a time-efficient flapless approach for placing implants in sites with block grafts.

Computer-Aided Design/Computer-Aided Manufacturing Milling of Allogeneic Blocks Following Three-Dimensional Maxillofacial Graft Planning.

Despite the advent of stereolithography in craniofacial surgery for creating surgical guides and custom synthetic scaffolds, little is known about the feasibility of computer-aided design/computer-aided manufacturing (CAD/CAM) milling of freeze-dried allogeneic bone blocks following previously designed volumetric graft plans. The aim of this technical report is to present a methodology for CAD/CAM milling to achieve the volume and shape of allogeneic bone blocks as estimated by using a virtual planning software. To perform the current methodology, an ex vivo simulation was performed. The milled allogeneic block presented satisfactory dimensional accuracy as compared with the respective three-dimensional virtual model.

A three-dimensional finite element analysis of the sports mouthguard.

BACKGROUND/AIM: The aim of this study was to evaluate the compressive and tensile stresses on dentin and enamel in five different situations: no mouthguard and mouthguards from 1 mm thickness up to 4 mm thickness, using finite element analysis. MATERIALS AND METHODS: A three-dimensional geometry of an upper right central incisor was obtained from a computed tomography and transformed into a mesh separating enamel from dentin. A mouthguard was created covering the buccal surface of the enamel in different thicknesses, and a rubber ball with a velocity of 5 m s(-1) was made as the impact object. RESULTS: The maximum principal stress and the minimal principal stress were evaluated in all situations on dentin and enamel. Both maximum and minimal stress on enamel had the greatest value on the control situation (no mouthguard), and their value decreased as the mouthguard thickness increased. The reduction ranged from 66.62% to 85.5% for compressive stress and from 9.76% to 33.37% for tensile stress on enamel. The results for dentin were similar among the situations with or without mouthguards. CONCLUSION: The mouthguard had beneficial effect considering the stresses on enamel, and between the mouthguard thickness of 3 and 4 mm, there was minimum difference.

Mouthguard: a new technique for the partially edentulous patient.

Over the last decades, several articles have corroborated the need of using mouthguards in sports activities, manufactured with ethylene vinyl acetate (EVA) as their main material. There are different mouthguards techniques used by dentists worldwide to prevent injuries. A technique has been developed to help athletes, especially the partially edentulous patients, who were not getting the proper protection. The mouthguard technique consists in making EVA fillings to improve the adjustment and esthetics of mouthguard used by athletes. It is the authors' conviction that the technique may prevent injuries in sports activities without impairing the athletes' safety and esthetics.

Analysis of the atrophic mandible rehabilitated with fixed total prosthesis on mono or bicortical implants.

Rehabilitation of edentulous atrophic mandibles involves the placement of implants in the anterior segment of the mandible. The primary stability of these implants can be improved using the base of the mandible as complementary anchorage (bicorticalization). This study aimed to analyze the biomechanics of atrophic mandibles rehabilitated with monocortical or bicortical implants. Two three-dimensional virtual models of edentulous mandibles with severe atrophy were prepared. Four monocortical implants were placed in one model (McMM), and four bicortical implants were placed in the other (BcMM). An implant-supported total prosthesis was prepared for each model. Then, a total axial load of 600 N was applied to the posterior teeth, and its effects on the models were analyzed using finite element analysis. The highest compressive stresses were concentrated in the cervical region of the implants in the McMM (-32.562 Mpa); in the BcMM, compressive stresses were distributed in the upper and lower cortex of the mandible, with increased compressive stresses at the distal implants (-63.792 Mpa). Thus, we conclude that axial loading forces are more uniformly distributed in the peri-implant bone when using monocortical implants and concentrated in the apical and cervical regions of the peri-implant bone when using bicortical implants.

A finite element study on the risk of bone loss around posterior short implants in an atrophic mandible.

PURPOSE: This study aimed to evaluate the risk of bone loss around single short molar crown-supporting implants in an atrophic mandible. METHODS: Implants of different lengths (L = 4 or 6 mm) and diameters (Ø = 4.1 or 4.8 mm) were placed in the molar area of an atrophic mandible. Additional control mandible models were simulated for 4.1 mm diameter implants (L = 4, 6, 8, and 10 mm). A vertical masticatory load of 200 N was applied to three or six occlusal contact areas (3ca or 6ca) of the prosthetic crown. The bone strain energy density (SED) of 109.6 µJ/mm3 was assumed to be the pathological threshold for cortical bone. The peri-implant bone resorption risk index (PIBRri) was calculated by dividing the maximum SED of the crestal cortical bone by the SED pathological threshold. RESULTS: Increasing the implant length from 4 to 6 mm, implant diameter from 4.1 to 4.8 mm, and number of contact areas from 3 to 6 reduced the SED and PIBRri values by approximately 20%, 35%, and 40%, respectively, when comparing pairs of models that isolated a specific variable. All models with 6ca had a low bone resorption risk (PIBRri<0.8), while the Ø4.1 short implant with 3ca had a medium (0.8≤PIBRri≤1.0) or high (PIBRri>1.0) resorption risk. CONCLUSIONS: Increasing the diameter or occlusal contact area of a 4 mm short implant in an atrophic mandible resulted in reduced bone resorption risks, similar to or lower than those observed in a regular mandible with standard-length implants.

Can maxilla and mandible bone quality explain differences in orthodontic mini-implant failures?

Purpose: This study aimed to compare the risk of orthodontic mini-implant (OMI) failure between maxilla and mandible. A critical analysis of finite-element studies was used to explain the contradiction of the greatest clinical success for OMIs placed in the maxilla, despite the higher quality bone of mandible. Materials and Methods: Four tridimensional FE models were built, simulating an OMI inserted in a low-dense maxilla, control maxilla, control mandible, and high-dense mandible. A horizontal force was applied to simulate an anterior retraction of 2 N (clinical scenario) and 10 N (overloading condition). The intra-bone OMI displacement and the major principal bone strains were used to evaluate the risk of failure due to insufficient primary stability or peri-implant bone resorption. Results: The OMI displacement was far below the 50-100 µm threshold, suggesting that the primary stability would be sufficient in all models. However, the maxilla was more prone to lose its stability due to overload conditions, especially in the low-dense condition, in which major principal bone strains surpassed the pathologic bone resorption threshold of 3000 µstrain. Conclusions: The differences in orthodontic mini-implant failures cannot be explained by maxilla and mandible bone quality in finite-element analysis that does not incorporate the residual stress due to OMI insertion.

The Usefulness of a Facial Digital Biobank for Ameloblastoma Resection and Fracture Fixation - A Case Report.

Rationale: Ameloblastoma often requires complex facial treatments such as resection and reconstruction, which can be aided using three-dimensional resources towards improved surgical planning, reduction of surgical time, and customization. Patient Concerns: A 51-year-old patient, concerned about submandibular volumetric increase discovered performing imaging exams to install dental implants. Diagnosis and Treatment: Diagnosed with ameloblastoma, he underwent uneventful partial mandibular resection and placement of prebent mandibular reconstruction plate. Four months later, following a motorcycle accident, a deflection of the plate and mandibular fracture was observed. Using the initial prototyping, a new reconstruction plate was customized and surgically placed to reduce the mandibular fracture, with adequate titanium plate adaptation to the remaining bone and maintenance of aesthetic mandibular contour. Outcomes and Take-away Lessons: The current digital dentistry resources, such as computed tomography and intraoral scan, can be recovered and used as a backup of recorded anatomy anytime in future, providing a long-lasting facial digital biobank.

Correlation between magnetic resonance imaging and cone-beam computed tomography for maxillary sinus graft assessment.

PURPOSE: Little is known regarding the accuracy of clinical magnetic resonance imaging (MRI) protocols with acceptable scan times in sinus graft assessment. The aim of this study was to evaluate the correlations between MRI and cone-beam computed tomographic (CBCT) measurements of maxillary sinus grafts using 2 different clinical MRI imaging protocols. MATERIALS AND METHODS: A total of 15 patients who underwent unilateral sinus lift surgery with biphasic calcium phosphate were included in this study. CBCT, T1-weighted MRI, and T2-weighted MRI scans were taken 6 months after sinus lift surgery. Linear measurements of the maximum height and buccolingual width in coronal images, as well as the maximum anteroposterior depth in sagittal images, were performed by 2 trained observers using CBCT and MRI Digital Imaging and Communication in Medicine files. Microcomputed tomography (micro-CT) was also performed to confirm the presence of bone tissue in the grafted area. Correlations between MRI and CBCT measurements were assessed with the Pearson test. RESULTS: Significant correlations between CBCT and MRI were found for sinus graft height (T1-weighted, r=0.711 and P<0.05; T2-weighted, r=0.713 and P<0.05), buccolingual width (T1-weighted, r=0.892 and P<0.05; T2-weighted, r=0.956 and P<0.05), and anteroposterior depth (T1-weighted, r=0.731 and P<0.05; T2-weighted, r=0.873 and P<0.05). The presence of bone tissue in the grafted areas was confirmed via micro-CT. CONCLUSION: Both MRI pulse sequences tested can be used for sinus graft measurements, as strong correlations with CBCT were found. However, correlations between T2-weighted MRI and CBCT were slightly higher than those between T1-weighted MRI and CBCT.

Impactos da COVID-19 aos acadêmicos de Odontologia no Brasil / Impactos del COVID-19 en estudiantes de Odontología en Brasil / Impact of COVID-19 on dental students in Brazil

O presente estudo teve por objetivo analisar os efeitos da pandemia da COVID-19 sobre o rendimento e aproveitamento acadêmico dos estudantes de Odontologia no Brasil. O estudo transversal descritivo foi realizado por meio da aplicação de questionário usando o aplicativo Google Forms, compartilhado via redes sociais como WhatsApp, Instagram, Facebook e endereços eletrônicos (e-mails) para 383 estudantes, número definido por cálculo amostral. Após a realização de estudo piloto, utilizou-se a técnica da "bola de neve virtual" para a coleta das respostas. Realizou-se análise descritiva e inferencial dos dados por meio de frequências e regressões logísticas multinominais com nível de significância de 5%. A maioria dos estudantes (72%) eram do sexo feminino, 81,5%oriundos de instituições privadas. Houve insatisfação tanto para com as aulas remotas (42,1% totalmente e 25,4% parcialmente) quanto para a formação acadêmica (44,1% totalmente e 25,6% parcialmente), relatou-se queda de rendimento em 70,7% dos estudantes e pensamento em abandonar os estudos (40,5% afirmam que sim e 10,2% relatam "talvez"). Região de residência e dispositivo utilizado para acompanhar as aulas influenciaram no pensamento em desistir dos estudos (p<0,05 e p=0,031 respectivamente), assim como o nível de conhecimento em informática influenciou no rendimento acadêmico durante a pandemia (p=0,009). Conclui-se que houve queda no rendimento acadêmico dos alunos durante a pandemia. O despreparo dos estudantes frente ao modelo remoto e as dificuldadesrelacionadas à aprendizagem demonstram que o Ensino Remoto Emergencial não foi suficiente para contemplar a gama de habilidades a serem desenvolvidas durante a formação (AU).

El presente estudio tuvo como objetivo analizar los efectos de la pandemia COVID-19 en el rendimiento y logro académico de los estudiantes de odontología en Brasil. El estudio descriptivo transversal se realizó mediante la aplicación de un cuestionario utilizando la aplicación Google Forms, compartido a través de redes sociales. redes como WhatsApp, Instagram, Facebook y direcciones electrónicas (e-mails) de 383 estudiantes, número definido mediante cálculo muestral. Tras realizar un estudio piloto,se utilizó la técnica de la "bola de nieve virtual" para recoger respuestas. Se realizó análisis descriptivo e inferencial de los datos mediante frecuencias y regresiones logísticas multinomiales con un nivel de significancia del 5%. La mayoría de los estudiantes (72%) eran mujeres, el 81,5% de instituciones privadas. Hubo insatisfacción tanto con las clases remotas (42,1% total y 25,4% parcialmente) como con la formación académica (44,1% total y 25,6% parcial), reportándose una caída en el rendimiento del70,7% de los estudiantes que pensaron en abandonar sus estudios (40,5% dijo sí y el 10,2% dijo "tal vez"). La región de residencia y el dispositivo utilizado para seguir clases influyeron en el pensamiento de abandonar los estudios (p<0,05 y p=0,031 respectivamente), así como el nivel de conocimientos de informática influyó en el rendimiento académico durante la pandemia (p=0,009). Se concluye que hubo una caída en el rendimiento académico de los estudiantes durante la pandemia. La falta de preparación de los estudiantes para el modelo remoto y las dificultades relacionadas con el aprendizaje demuestran que la Educación Remota de Emergencia no fue suficiente para cubrir el conjunto de habilidades a desarrollar durante la formación (AU).

The aim of the present study was to analyze the effects of the COVID-19 pandemic on the academic performance of dental students in Brazil. A descriptive cross-sectional study was conducted using a questionnaire available on the Google Forms application andshared via social networks, such as WhatsApp, Instagram and Facebook, as well as electronic addresses (e-mails) to 383 students. This number was defined by the sample size calculation. After conducting a pilot study, the "virtual snowball" technique was used to collect responses. Descriptive and inferential analyses of the data were performed using frequencies and multinomial logistic regression, with a 5% significance level. Most students (72%) were female and studied at private dental schools (81.5%). Dissatisfaction was found for both remote classes (42.1% completely and 25.4% partially) and academic training (44.1% completely and 25.6% partially), with a reported drop in performance among 70.7% of the students and thoughts of abandoning their studies (40.5% answered "yes" and 10.2% answered "maybe"). Region of residence and device used to follow classes exerted an influence on thoughts of abandoning studies (p <0.05 and p = 0.031, respectively). Moreover, the level of computer knowledge exerted an influence on academic performance during the pandemic (p = 0.009). In conclusion, a drop in academic performance occurred among dental students during the pandemic. The lack of preparedness for the remote model and difficulties related to learning demonstrate that "Emergency Remote Education" was insufficient to cover the range of skills to be developed during training (AU).

Analysis of the atrophic mandible rehabilitated with fixed total prosthesis on mono or bicortical implants

Abstract Rehabilitation of edentulous atrophic mandibles involves the placement of implants in the anterior segment of the mandible. The primary stability of these implants can be improved using the base of the mandible as complementary anchorage (bicorticalization). This study aimed to analyze the biomechanics of atrophic mandibles rehabilitated with monocortical or bicortical implants. Two three-dimensional virtual models of edentulous mandibles with severe atrophy were prepared. Four monocortical implants were placed in one model (McMM), and four bicortical implants were placed in the other (BcMM). An implant-supported total prosthesis was prepared for each model. Then, a total axial load of 600 N was applied to the posterior teeth, and its effects on the models were analyzed using finite element analysis. The highest compressive stresses were concentrated in the cervical region of the implants in the McMM (-32.562 Mpa); in the BcMM, compressive stresses were distributed in the upper and lower cortex of the mandible, with increased compressive stresses at the distal implants (-63.792 Mpa). Thus, we conclude that axial loading forces are more uniformly distributed in the peri-implant bone when using monocortical implants and concentrated in the apical and cervical regions of the peri-implant bone when using bicortical implants.

Resumo A instalação de implantes no segmento anterior da mandíbula, é um tratamento utilizado para reabilitação de mandíbulas atróficas. Para melhorar a estabilidade primária desses implantes, a base da mandíbula pode ser usada como ancoragem complementar (bicorticalização). Este estudo objetiva analisar a biomecânica de mandíbulas atróficas, reabilitadas com prótese sobre implantes monocorticalizados ou bicorticalizados. Para isso foram confeccionados dois modelos tridimensionais de mandíbula desdentada e com atrofia severa. Em um deles foram instalados 4 implantes monocorticalizados (McMM), enquanto no segundo foram instalados 4 implantes bicorticalizados (BcMM); foi modelada uma prótese total implantossuportada sobre cada modelo e aplicada uma carga axial total de 600N, distribuída nos dentes posteriores. Os modelos foram submetidos à análise de elementos finitos. Os resultados demonstraram que as maiores tensões de compressão se concentraram na região cervical dos implantes no McMM, (-32,562Mpa); já no BcMM, as tensões de compressão foram observadas nas corticais superior e inferior da mandíbula e aumento das tensões de compressão nos implantes distais (-63,792 Mpa). Com isso, concluímos as forças de carregamento axial apresentam-se melhor distribuídas pela estrutura óssea peri-implantar, em implantes monocorticalizados. e as tensões sobre o tecido ósseo, no BcMM, ocorrem nas regiões que circundam as regiões apicais e cervicais do implante.

Avaliação dos impactos financeiros gerados pela pandemia da Covid-19 aos técnicos de prótese dentária no Brasil / Assessing the financial impacts of the COVID-19 pandemic on denture technicians in Brazil

Resumo Introdução a pandemia da Covid-19 e medidas de controle da sua expansão impactaram diferentes segmentos da economia, dentre eles os profissionais da Odontologia. Objetivo este trabalho analisou o impacto financeiro gerado pela pandemia da Covid-19 aos técnicos de prótese dentária (TPDs) no Brasil. Material e método por meio de um estudo transversal descritivo, aplicou-se aos TPDs do Brasil um questionário relacionado ao perfil sociodemográfico e profissional, impacto financeiro e medidas adotadas para minimizar seus efeitos. O questionário foi aplicado de forma on-line em redes sociais entre 27 de janeiro e 15 de fevereiro de 2021. Resultado demonstrou-se que 59,8% dos participantes eram do sexo masculino; 47,5% até 30 anos de idade e 57,3% com menos de 10 anos de prática. As medidas para contenção da propagação do coronavírus impactaram financeiramente 89,6% dos participantes; 72,0% interromperam totalmente seus trabalhos; 97,7% tiveram redução no faturamento; 98,2% tiveram mudança na rotina de trabalho; 94,8% tiveram aumento das despesas do laboratório no período; houve queda do faturamento para 41,2% entre 0% e 25,0% e para 36,3% entre 25,0% e 50,0%; 66,6% continuaram trabalhando durante a pandemia devido à sua situação financeira. Não pensaram em fechar seu laboratório de forma definitiva 71,8% dos participantes; 92,2% seguiram rotineiramente os cuidados de higienização e 21,6% fizeram uso das reservas financeiras. Conclusão os TPDs tiveram impacto financeiro durante o período da pandemia da Covid-19 causado principalmente pela diminuição da carga horária de trabalho, redução do faturamento e aumento do custo operacional devido à mudança na rotina de biossegurança.

Abstract Introduction the COVID-19 pandemic and measures to control its expansion impacted different segments of the economy, including dentistry professionals. Objective this study analyzed the financial impact of the COVID-19 pandemic on dental technicians in Brazil. Material and method this is a descriptive cross-sectional study with the application of a questionnaire of sociodemographic and professional profile, financial impact, and effect containment measures to dental technicians in Brazil. The questionnaire was applied online on social networks between January 27 and February 15, 2021. Result 59.8% of the participants were male, with 47.5% aged up to 30 years, and 57.3% with less than 10 years of practice. The measures to contain the spread of the coronavirus had a financial impact on 89.6% of the participants: 72.0% had their work completely interrupted, 97.7% had their billing reduced, 98.2% changed their work routine, and 94.8% had higher laboratory expenses in the period. Revenue decreased between 0% and 25.0% for 41.2% and between 25.0% and 50.0% for 36.3%. In addition, 66.6% continued working during the pandemic due to their financial situation. 71.8% of the participants did not consider closing their laboratory permanently, whereas 92.2% followed hygiene protocols routinely and 21.6% made use of their financial reserves. Conclusion dental technicians were financially impacted by the COVID-19 pandemic, mainly caused by fewer working hours, revenue reduction, and higher operating costs due to the change in the biosafety routine.

Detection of furcation involvement using periapical radiography and 2 cone-beam computed tomography imaging protocols with and without a metallic post: An animal study.

PURPOSE: The purpose of this study was to assess the accuracy, sensitivity, and specificity of the diagnosis of incipient furcation involvement with periapical radiography (PR) and 2 cone-beam computed tomography (CBCT) imaging protocols, and to test metal artifact interference. MATERIALS AND METHODS: Mandibular second molars in 10 macerated pig mandibles were divided into those that showed no furcation involvement and those with lesions in the furcation area. Exams using PR and 2 different CBCT imaging protocols were performed with and without a metallic post. Each image was analyzed twice by 2 observers who rated the absence or presence of furcation involvement according to a 5-point scale. Receiver operating characteristic (ROC) curves were used to evaluate the accuracy, sensitivity, and specificity of the observations. RESULTS: The accuracy of the CBCT imaging protocols ranged from 67.5% to 82.5% in the images obtained with a metallic post and from 72.5% to 80% in those without a metallic post. The accuracy of PR ranged from 37.5% to 55% in the images with a metallic post and from 42.5% to 62.5% in those without a metallic post. The area under the ROC curve values for the CBCT imaging protocols ranged from 0.813 to 0.802, and for PR ranged from 0.503 to 0.448. CONCLUSION: Both CBCT imaging protocols showed higher accuracy, sensitivity, and specificity than PR in the detection of incipient furcation involvement. Based on these results, CBCT may be considered a reliable tool for detecting incipient furcation involvement following a clinical periodontal exam, even in the presence of a metallic post.

Diagnosis of alveolar and root fractures: an in vitro study comparing CBCT imaging with periapical radiographs.

OBJECTIVE: To compare periapical radiograph (PR) and cone-beam computed tomography (CBCT) in the diagnosis of alveolar and root fractures. MATERIAL AND METHODS: Sixty incisor teeth (20 higid and 40 with root fracture) from dogs were inserted in 60 anterior alveolar sockets (40 higid and 20 with alveolar fracture) of 15 macerated canine maxillae. Each fractured socket had a root fractured tooth inserted in it. Afterwards, each maxilla was submitted to PR in two different vertical angulation incidences, and to CBCT imaging with a small field of view (FOV) and high-definition protocol. Images were randomized and posteriorly analyzed by two oral and maxillofacial radiologists two times, with a two-week interval between observations. RESULTS: Sensitivity and specificity values were good for root fractures for PR and CBCT. For alveolar fractures, sensitivity ranged from 0.10 to 0.90 for PR and from 0.50 to 0.65 for CBCT. Specificity for alveolar fractures showed lower results than for root fractures for PR and CBCT. Areas under the ROC curve showed good results for both PR and CBCT for root fractures. However, results were fair for both PR and CBCT for alveolar fractures. When submitted to repeated measures ANOVA tests, there was a statistically significant difference between PR and CBCT for root fractures. Root fracture intraobserver agreement ranged from 0.90 to 0.93, and alveolar fracture intraobserver agreement ranged from 0.30 to 0.57. Interobserver agreement results were substantial for root fractures and poor/fair for alveolar fractures (0.11 for PR and 0.30 for CBCT). CONCLUSION: Periapical radiograph with two different vertical angulations may be considered an accurate method to detect root fractures. However, PR showed poorer results than CBCT for the diagnosis of alveolar fractures. When no fractures are diagnosed in PR and the patient describes pain symptoms, the subsequent exam of choice is CBCT.

Retrospective Analysis of the Prevalence of Teeth Endodontically Treated from Radiographs of Individuals from the Midwest Region of Brazil / Análise Retrospectiva da Prevalência de Dentes Tratados Endodônticamente a Partir de Radiografia de Indivíduos da Região do Centro Oeste no Brasil

Endodontic treatment is common in dentistry and for a correct diagnosis it is necessary to observe clinical and radiographic signs, taking into account pulp and periapical changes in the element to be treated. Studying this frequency can contribute to the literature, elucidating whether the greatest number of cases is occurring in young or elderly patients, women or men, anterior or posterior teeth. The objective of this study was to analyze the prevalence of endodontically treated teeth, through 900 panoramic radiographs. A cross-sectional study was carried out evaluating the prevalence of teeth treated endodontically from a sample of 900 panoramic radiographs, corresponding to exams performed in 2020, in a radiological clinic located in central west Brazil. The sample consisted of 540 (60%) female subjects and 360 (40%) male subjects, aged between 18 and 88 years old, being more prevalent for Individuals <31 years old with (34.9%) Sample. The prevalence of endodontically treated teeth was analyzed, the results showed 1,236 teeth in this condition, individually analyzing the upper right central incisor was the most frequent 9.22%, while for group analysis the upper teeth were 7.06%. Therefore, there was a higher prevalence of teeth treated endodontically in the maxilla, the tooth with the highest treatment index, the right upper central incisor. Women were more affected and it was observed that with increasing age, the number of teeth treated endodontically also increases. (AU)

O tratamento endodôntico é frequente na odontologia e para um correto diagnóstico é necessário observar sinais clínicos e radiográficos, levando em consideração as alterações pulpares e periapicais no elemento à ser tratado. Estudar essa frequência pode colaborar com a literatura, elucidando se o maior número de casos está ocorrendo em pacientes jovens ou idosos,mulheres ou homens, dentes anteriores ou posteriores O objetivo desse presente estudo foi analisar a prevalência de dentes tratados endodônticamente, por meio de 900 radiografias panorâmicas. Foi realizado um estudo transversal avaliando prevalência de dentes tratados endodônticamente a partir de uma amostra de 900 radiografias panorâmicas, correspondentes a exames realizados em 2020, em uma clínica radiológica situada no centro oeste do Brasil. A amostra foi constituída por 540 (60%) Indivíduos do gênero feminino e 360 (40%) do masculino, com idade entre 18 e 88 anos de idade, sendo mais prevalente para Indivíduos <31 anos de idade com (34,9%) da amostra. Foi analisada a prevalência de dentes tratados endodônticamente, os resultados mostraram 1.236 dentes nesta condição, analisando individualmente o incisivo central superiores direito foi o mais frequente 9,22%, enquanto para análise de dentes por grupos foram os dentes anteriores superiores 7,06%. Portanto, houve uma maior prevalência de dentes tratados endodônticamente em maxila, o dente com maior índice de tratamento o incisivo central superior direito. Mulheres foram mais acometidas e observou-se que com o aumento da idade, aumenta-se também o número de dentes tratados endodônticamente. (AU)

Oral and maxillofacial anatomical structures acknowledgment through cone beam computed tomography images ­ a teaching practice experience / Conhecimento de estruturas anatômicas em imagens de tomografia computadorizada por feixe cônico ­ experiência de prática pedagógica

This study proposed to report a cone beam computed tomography (CBCT) teaching methodology applied to Dental School students by assessing mid-term and end-term exams correct recognition of anatomical structures. Students were instructed on oral and maxillofacial anatomical structures and clinical applications of CBCT imaging through lectures and hands-on classes, comprising forty-five hours of classes. They were submitted to two tests, the first one at mid-term and the second one at end-term. Anatomical structures recognition test scores (three variables: 1) name, 2) side ­ left/right and 3) multiplanar reconstructions (MPR) orthogonal images identification) were compared to verify if learning improvement occurred. Medians and Wilcoxon tests compared mid with end term exams. Median values for variable 1 were 6.0 (mid-term) and 8.0 (end-term). With regard to variable 2, median values ranged from 9.0 (mid-term) to 10.0 (end-term). When variable 3 results were analyzed, both mid-term and end-term medians were 10.0. Wilcoxon test (p<0.05) showed significant differences when comparing mid-term and end-term exams in each of the three categories. Linear correlations were established among the three categories. Correlations were statistically significant for two associations ("anatomical structure name" with "anatomical structure side", and "anatomical structure name" with "MPR images"). Predoctoral dental school students presented a comprehensive improvement in terms of correctly recognizing anatomical structures name and side, as well as MPR images when comparing mid-term and end-term tests (AU).

O objetivo deste estudo foi relatar uma metodologia de ensino de tomografia computadorizada de feixe cônico (TCFC) aplicada a estudantes de graduação, avaliando o conhecimento de estruturas anatômicas do complexo dentomaxilofacial. Os estudantes foram orientados quanto às estruturas anatômicas e às aplicações clínicas da TCFC em aulas teóricas e práticas, compreendendo 45 horas de aula. Foram submetidos a duas avaliações, a primeira na metade do semestre, e a segunda no término do semestre. Os escores das avaliações (três variáveis: 1) nome, 2) lado - esquerdo/direito e 3) reconstruções multiplanares (RMP) - imagens ortogonais de identificação) foram comparados para verificar se houve melhora na aprendizagem. Testes de medianas e Wilcoxon compararam os exames intermediário e final. Os valores medianos para a variável 1 foram 6,0 (intermediário) e 8,0 (final). Em relação à variável 2, a mediana variou de 9,0 (intermediário) a 10,0 (final). Quando os resultados da variável 3 foram analisados, ambas as medianas foram 10,0. Houve diferença significativa (teste de Wilcoxon, p<0,05) quando foram comparados os exames intermediário e final, nas três categorias. Correlações lineares foram estabelecidas entre as três categorias e foram estatisticamente significantes para duas associações ("nome da estrutura anatômica" com "lado da estrutura anatômica" e "nome da estrutura anatômica" com "imagens da MPR"). Os estudantes de graduação apresentaram uma melhora em termos do reconhecimento correto das estruturas anatômicas, nome e lado, bem como imagens de MPR quando comparadas as duas avaliações (AU).

Diagnosis of alveolar and root fractures: an in vitro study comparing CBCT imaging with periapical radiographs

Abstract Objective To compare periapical radiograph (PR) and cone-beam computed tomography (CBCT) in the diagnosis of alveolar and root fractures. Material and Methods Sixty incisor teeth (20 higid and 40 with root fracture) from dogs were inserted in 60 anterior alveolar sockets (40 higid and 20 with alveolar fracture) of 15 macerated canine maxillae. Each fractured socket had a root fractured tooth inserted in it. Afterwards, each maxilla was submitted to PR in two different vertical angulation incidences, and to CBCT imaging with a small field of view (FOV) and high-definition protocol. Images were randomized and posteriorly analyzed by two oral and maxillofacial radiologists two times, with a two-week interval between observations. Results Sensitivity and specificity values were good for root fractures for PR and CBCT. For alveolar fractures, sensitivity ranged from 0.10 to 0.90 for PR and from 0.50 to 0.65 for CBCT. Specificity for alveolar fractures showed lower results than for root fractures for PR and CBCT. Areas under the ROC curve showed good results for both PR and CBCT for root fractures. However, results were fair for both PR and CBCT for alveolar fractures. When submitted to repeated measures ANOVA tests, there was a statistically significant difference between PR and CBCT for root fractures. Root fracture intraobserver agreement ranged from 0.90 to 0.93, and alveolar fracture intraobserver agreement ranged from 0.30 to 0.57. Interobserver agreement results were substantial for root fractures and poor/fair for alveolar fractures (0.11 for PR and 0.30 for CBCT). Conclusion Periapical radiograph with two different vertical angulations may be considered an accurate method to detect root fractures. However, PR showed poorer results than CBCT for the diagnosis of alveolar fractures. When no fractures are diagnosed in PR and the patient describes pain symptoms, the subsequent exam of choice is CBCT.

Avaliação bidimensional e tridimensional do ângulo de curvatura de dentes permanentes: comparação entre radiografia periapical e TCFC / Bidimensional and tridimensional root canal curvature angle evaluation: comparison between periapical radiography and CBCT

A curvatura dos canais radiculares pode ser considerada um grande desafio para o sucesso do tratamento endodôntico, por tal motivo é necessária uma boa compreensão da anatomia interna dental. Diversas técnicas para avaliação qualitativa e quantitativa da curvatura foram propostas desde o século XVIII, porém ainda não foi aceita uma técnica que pudesse fornecer a pesquisadores e profissionais clínicos descrição detalhada sobre a curvatura do canal. O objetivo do presente estudo foi descrever uma técnica baseada em coordenadas delimitadas na luz do canal radicular (denominada método de pontos), utilizando fórmulas matemáticas e programas de desenho computacional, para que fosse possível determinar, tanto de maneira bidimensional quanto tridimensional, o desvio da trajetória do canal (considerado como ângulo de curvatura), o quão acentuado é esse desvio (grau de curvatura) e determinar a região em que as curvaturas se encontram no canal. Além desse objetivo, a metodologia foi aplicada em quatro grupos dentais (incisivo lateral superior, pré-molar inferior, molar superior e molar inferior) para estudar possíveis diferenças entre os grupos e entre os seus terços radiculares. Para realizar o estudo foram utilizadas imagens bidimensionais (radiografia periapical) e tridimensionais (tomografia computadorizada por feixe cônico). Na análise bidimensional, a aplicabilidade da metodologia proposta foi demonstrada comparando o método de pontos aos métodos de Schneider e de Pruett sobre radiografias periapicais de pré-molares inferiores. Os resultados mostraram que o método de pontos obteve valores angulares maiores quando comparados às outras técnicas e houve forte correlação entre o maior valor angulado encontrado pelo presente método quando comparado ao cálculo do raio de curvatura pelo método de Pruett. Para a análise tridimensional, foi comparada angulação de curvatura dos quatro grupos dentários e comparando os resultados obtidos pelo método de Schneider (por ser o mais comumente empregado), método de pontos bidimensional e método de pontos tridimensional. Os resultados desta avaliação demonstraram que em todos os grupos o valor angular obtido pelo método em três dimensões foi maior quando comparado aos outros métodos, indicando que a angulação tridimensional não é totalmente considerada ao ser realizada uma análise bidimensional da estrutura. Ao analisar a diferença entre os grupos dentários, os resultados mostraram que os dentes multirradiculares (molares superiores e inferiores) apresentaram curvatura mais acentuada da encontrada em dentes unirradiculares e na comparação entre os terços radiculares, o terço apical foi a região que concentrou os maiores valores de curvatura de canal.