Effectiveness of Early Intervention with Palatal Expansion Versus Late Orthodontic Treatment for Correcting Maxillary Crowding.

Background: Maxillary crowding is a common orthodontic issue that can impact a patient's oral health and overall well-being. The timing of orthodontic treatment plays a crucial role in achieving optimal results. Materials and Methods: Thirty patients who received early intervention with palatal expansion (Group A) and 30 patients who underwent late orthodontic treatment (Group B) were included in this study. The age range for Group A was 8-10 years, while Group B had an age range of 16-18 years. Pretreatment and posttreatment records, including dental models and cephalometric radiographs, were analyzed to assess the effectiveness of the respective treatments. Results: In Group A, the mean duration of treatment was 12 months, and the maxillary crowding was corrected by an average of 4.5 mm. In Group B, the mean treatment duration was 24 months, and maxillary crowding was corrected by an average of 3.2 mm. The early intervention group (Group A) exhibited a statistically significant reduction in treatment duration and greater correction of maxillary crowding compared to the late orthodontic treatment group (Group B) (P < 0.05). Conclusion: Early intervention with palatal expansion is an effective approach for correcting maxillary crowding, leading to shorter treatment duration and greater improvement compared to late orthodontic treatment.

DilatedToothSegNet: Tooth Segmentation Network on 3D Dental Meshes Through Increasing Receptive Vision.

The utilization of advanced intraoral scanners to acquire 3D dental models has gained significant popularity in the fields of dentistry and orthodontics. Accurate segmentation and labeling of teeth on digitized 3D dental surface models are crucial for computer-aided treatment planning. At the same time, manual labeling of these models is a time-consuming task. Recent advances in geometric deep learning have demonstrated remarkable efficiency in surface segmentation when applied to raw 3D models. However, segmentation of the dental surface remains challenging due to the atypical and diverse appearance of the patients' teeth. Numerous deep learning methods have been proposed to automate dental surface segmentation. Nevertheless, they still show limitations, particularly in cases where teeth are missing or severely misaligned. To overcome these challenges, we introduce a network operator called dilated edge convolution, which enhances the network's ability to learn additional, more distant features by expanding its receptive field. This leads to improved segmentation results, particularly in complex and challenging cases. To validate the effectiveness of our proposed method, we performed extensive evaluations on the recently published benchmark data set for dental model segmentation Teeth3DS. We compared our approach with several other state-of-the-art methods using a quantitative and qualitative analysis. Through these evaluations, we demonstrate the superiority of our proposed method, showcasing its ability to outperform existing approaches in dental surface segmentation.

Evaluating and Comparing Flexure Strength of Dental Models Printed Using Fused Deposition Modelling, Digital Light Processing, and Stereolithography Apparatus Printers.

INTRODUCTION: The introduction of three-dimensional (3D) printing in dentistry has mainly focused on applications such as surgical planning, computer-guided templates, and digital impression conversions. Additive manufacturing (AM), also known as 3D printing, involves layering resin material sequentially to construct objects and is gaining recognition for its role in creating custom-made medical appliances. The field of orthodontics has also embraced this technological wave and with the advent of cost-effective printers and biocompatible resins, 3D printing has become increasingly feasible and popular in orthodontic clinics. The limitations of traditional plaster models may have prompted the emergence of 3D-printed models, but it led to enhancing treatment planning and device fabrication, particularly in orthodontics. Notable desktop printing technologies include fused deposition modelling (FDM), digital light processing (DLP), and stereolithography (SLA), each employing distinct methods and materials for fabricating appliances. Evaluating mechanical properties, like flexure strength, is crucial to determine the material's ability to withstand bending forces and thus prove useful in fabricating thermoformable appliances, surgical templates, etc. This study aims to assess the flexure strength of 3D-printed models using FDM, DLP, and SLA technology, providing insights into their suitability as replacements for conventional models and shedding some light on the durability and sustainability of 3D-printed models. MATERIALS AND METHODOLOGY: Cuboids measuring 20 x 5 x 2 mm were cut from models, creating 10 samples per printer group. These samples underwent flexure strength testing using a three-point bending system in a universal testing machine. RESULTS: The FDM group exhibited the highest flexure strength at 69.36 ± 6.03 MPa, while the DLP group showed the lowest flexure strength at 67.47 ± 20.58 MPa. The results can be attributed to the differences in resin materials used for fabrication, with FDM using acrylonitrile butadiene styrene (ABS) polymer and SLA/DLP using polymethyl methacrylate (PMMA), and also to the variation in their printing mechanism. CONCLUSION: The findings affirm the suitability of FDM models for orthodontic applications, suggesting enhanced efficiency and reliability in clinical practices.

Effect of different storage conditions on dimensional accuracy of 3D-printed dental models.

PURPOSE: The objective was to determine the accuracy of 3D-printed dental models subjected to different storage conditions using six different material and printer combinations. MATERIALS AND METHODS: Three completely dentate models were designed using dental CAD software (3Shape Dental System). A horseshoe-shaped solid base with a posterior horizontal bar was used. The models were printed in a horizontal direction against the building platform without support. The models were printed using six printers with the corresponding recommended resin material: Carbon M2 (DPR10), HeyGears A2D4K (Model HP UV2.0), Stratasys J5 (MED610), Stratasys Origin One (DM200), Envision One (E-Model LightDLP), and Asiga Pro4K (VeriModel) with a standard layer thickness of 50 µm. All printed models underwent scanning using a laboratory scanner (Sirona inEOS X5) after printing. Subsequently, the models were randomly assigned into three groups of storage conditions, LT: cold environment (4 ± 1°C), HT: hot and dry environment (50 ± 2°C), and RT: room temperature (25 ± 2°C) serving as the control. Each group was kept under the designated condition and was scanned at 1, 2, 3, 4, and 8 weeks. The total number of models (N) was 72, with 6 printers producing 12 models per printer for 3 storage conditions, resulting in 4 models for each storage condition and each printer. The generated STL files were imported into a 3D inspection software for comparison with the original STL files. In-tolerance percentage, the deviation RMS, trueness, and precision were obtained and analyzed with least square mean linear regression using JMP Pro 15 to identify the significant effects (α = 0.05). RESULTS: The in-tolerance percentage as-printed was significantly different among different printers. Significant dimension deviations were observed after the first week of storage at HT and with subsequent weeks of storage. RT and LT did not show significant dimensional changes. Models printed with Carbon M2 showed the highest in-tolerance percentages compared to the other printers. CONCLUSIONS: The model deviations were affected by storage conditions and the printer used, with high-temperature storage showed least stability compared to low and room temperatures. No significant difference was observed between low and room temperature storage conditions. The Carbon M2 printer showed the highest accuracy among all printers tested. The region had a significant effect on the deviation measured, with the abutment body showing the least deviation. Among the 3D printers evaluated, A2D4K by HeyGears and Carbon M2 printers demonstrated the highest accuracy in terms of both precision and trueness.

Accuracy of models of partially edentulous arches obtained by three-dimensional printing: An in vitro study.

Aim: The aim of this study was to evaluate the accuracy of models of partially edentulous arches obtained by three-dimensional (3D) printing. Settings and Design: This was an in vitro study. Materials and Methods: Fifteen partially edentulous models were evaluated, using two methods of measuring dimensions: virtual, using the Standard Tessellation Language files of the models and software (control group), and physical, through printing the models and digital caliper (test group). For both methods, measurements were made regarding the dimensions of the teeth (width and length - buccal/lingual or palatal/occlusal) and distances between the teeth. Statistical Analysis Used: For the variable of linear measurements (width and length) and distances between teeth of the same hemiarch, the Wilcoxon test was used, while for the variable between opposite hemiarches, the paired t-test was used. Results: In the evaluation of the linear measurements, a significant difference was observed only when the width of the molar tooth was analyzed (P = 0.014). When the buccal length was measured, all teeth had linear measurements provided by the virtual method that was lower than the physical (P = 0.000), as well as the lingual/palatal length in incisors (P = 0.003) and molars (P = 0.009) and in total (P = 0.001). As for the analyses between teeth, no difference was identified between the measurements provided by the virtual method compared to the physical one. Conclusions: The 3D printer used to print partially edentulous models provided linear distortions in the teeth but without changes in the distances between teeth of the same hemiarch and between teeth of opposite hemiarches.

Diagnostic Applications of Intraoral Scanners: A Systematic Review.

In addition to their recognized value for obtaining 3D digital dental models, intraoral scanners (IOSs) have recently been proven to be promising tools for oral health diagnostics. In this work, the most recent literature on IOSs was reviewed with a focus on their applications as detection systems of oral cavity pathologies. Those applications of IOSs falling in the general area of detection systems for oral health diagnostics (e.g., caries, dental wear, periodontal diseases, oral cancer) were included, while excluding those works mainly focused on 3D dental model reconstruction for implantology, orthodontics, or prosthodontics. Three major scientific databases, namely Scopus, PubMed, and Web of Science, were searched and explored by three independent reviewers. The synthesis and analysis of the studies was carried out by considering the type and technical features of the IOS, the study objectives, and the specific diagnostic applications. From the synthesis of the twenty-five included studies, the main diagnostic fields where IOS technology applies were highlighted, ranging from the detection of tooth wear and caries to the diagnosis of plaques, periodontal defects, and other complications. This shows how additional diagnostic information can be obtained by combining the IOS technology with other radiographic techniques. Despite some promising results, the clinical evidence regarding the use of IOSs as oral health probes is still limited, and further efforts are needed to validate the diagnostic potential of IOSs over conventional tools.

Evaluation and comparison of linear and diagonal odontometry of first molars as a tool for gender discrimination; assessed in a population from Maharashtra.

Background: Linear odontometry is customarily used in gender determination which can pose difficulties in cases of tooth decay, attrition since they mainly involve the proximal surfaces. Objectives: The present cross-sectional observation study, estimated the efficacy of alternative measurements, that is, diagonal measurements and cervical measurements in gender determination in comparison to routine odontometry. Material and Methods: A total of 200 dental cast models (upper and lower) of 100 individuals (50 male and 50 female) from Maharashtra state were included. Results: Univariate discriminant function analysis showed that, in maxillary molars, MD width gave the highest gender dimorphism of 64%, followed by BL with 62%. In the mandibular teeth, MD gave an accuracy of 75% followed by MB-DL with 73%. Multivariate logistic regression analysis showed that overall diagonal and linear measurements gave the highest dimorphism of 81% with 80% correctly identified as females and 82% as males. The mandibular MD, BL and MB-DL gave an accuracy of 79% with 78% corrected identified as females and 80% correctly identified as males. Mandibular ML-DB and Cervical DB-CML together gave an accuracy of 77% and mandibular MD with75%. Conclusion: Thus, the study proves that diagonal measurements give almost equivalent or better results than linear measurements in gender determination.

Dental changes induced by a modified Herbst appliance followed by fixed appliances: A digital dental model analysis.

BACKGROUND: Herbst therapy is an effective treatment for Class II malocclusions. However, the maintenance of the effects after fixed appliances treatment remains questionable. This retrospective study aimed to assess, using digital dental models, the sagittal and transverse dental arch changes in young patients during two Class II Division 1 treatment phases, first with modified Herbst appliance (HA) and then with fixed appliances. METHODS: The treated group (TG) comprised 32 patients (17 boys, 15 girls; mean age, 12.85 ± 1.16 years) treated with HA and fixed appliances. The control group comprised 28 patients (13 boys, 15 girls; mean age, 12.21 ± 1.35 years) with untreated Class II malocclusions. Digital models were obtained immediately before and after HA therapy and after fixed appliances. Data were statistically analyzed. RESULTS: Compared with the control group, the TG showed an increase in maxillary and mandibular arch perimeters and in intercanine and intermolar arch widths, a decrease in overjet and overbite, and an improvement in canine and molar relationships. In the time after HA therapy until the end of fixed appliances treatment, the TG showed a decrease in maxillary and mandibular arch perimeters, overjet, upper and lower intermolar widths; an increase in molar Class II relationship; and no changes in canine relationship, overbite, and upper and lower intercanine widths. CONCLUSIONS: In this sample of patients treated with HA, on average, there was an improvement in the Class II relationship, which seemed to remain after fixed appliances. The transverse dental changes achieved in HA phase relapsed after treatment with fixed appliances.

Three-dimensional changes after maxillary molar distalization with a miniscrew-anchored cantilever.

OBJECTIVES: To evaluate the changes after maxillary molar distalization in Class II malocclusion using the miniscrew-anchored cantilever with an extension arm. MATERIALS AND METHODS: The sample included 20 patients (9 male, 11 female; mean age 13.21 ± 1.54 years) with Class II malocclusion, treated with the miniscrew-anchored cantilever. Lateral cephalograms and dental models obtained before (T1) and after molar distalization (T2) were evaluated using Dolphin software and 3D Slicer. Superimposition of digital dental models using regions of interest on the palate was performed to evaluate three-dimensional displacement of maxillary teeth. Intragroup change comparisons were performed using dependent t-test and Wilcoxon test (P < 0.05). RESULTS: The maxillary first molars were distalized to overcorrected Class I. The mean distalization time was 0.43 ± 0.13 years. Cephalometric analysis demonstrated significant distal movement of the maxillary first premolar (-1.21 mm, 95% confidence interval [CI]: -0.45, -1.96) and maxillary first (-3.38 mm, 95% CI: -2.88, -3.87) and second molars (-2.12 mm, 95% CI: -1.53, -2.71). Distal movements increased progressively from the incisors to the molars. The first molar showed small intrusion (-0.72 mm, 95% CI: 0.49, -1.34). In the digital model analysis, the first and second molars showed a crown distal rotation of 19.31° ± 5.71° and 10.17° ± 3.84°, respectively. The increase in maxillary intermolar distance, evaluated at the mesiobuccal cusps, was 2.63 ± 1.56 mm. CONCLUSIONS: The miniscrew-anchored cantilever was effective for maxillary molar distalization. Sagittal, lateral, and vertical movements were observed for all maxillary teeth. Distal movement was progressively greater from anterior to posterior teeth.

Reproducibility and reliability of digital occlusal planning for orthognathic surgery.

The digital articulation of dental models is gradually replacing the conventional physical approach for occlusal prediction planning. This study was performed to compare the accuracy and reproducibility of free-hand articulation of two groups of digital and physical dental models, 12 Class I (group 1) and 12 Class III (group 2). The models were scanned using an intraoral scanner. The physical and digital models were independently articulated 2 weeks apart by three orthodontists to achieve the maximum inter-digitation, with coincident midlines and a positive overjet and overbite. The occlusal contacts provided by the software color-coded maps were assessed and the differences in the pitch, roll, and yaw were measured. The reproducibility of the achieved occlusion of both the physical and digital articulation was excellent. The z-axis displayed the smallest absolute mean differences of 0.10 ± 0.08 mm and 0.27 ± 0.24 mm in the repeated physical and repeated digital articulations, respectively, both in group 2. The largest discrepancies between the two methods of articulation were in the y-axis (0.76 ± 0.60 mm, P = 0.010) and in roll (1.83° ± 1.72°, P = 0.005). The overall measured differences were< 0.8 mm and< 2°. Despite the steep learning curve, digital occlusal planning is accurate enough for clinical applications.

Elaboración de modelos dentales didácticos en resina epóxica / Elaboration of didactic dental models in epoxy resin

Los modelos de estudio son un registro fundamental para el diagnóstico, el plan de tratamiento, la presentación de caso y la evaluación del progreso del tratamiento dental; son registros anatomofisiológicos de las arcadas dentarias que sirven para evaluar la dentición en los tres planos del espacio y la oclusión en la relación cúspide-fosa, en una dimensión estática y dinámica. Para obtener los modelos de estudio es imprescindible obtener impresiones totales con diversos materiales de impresión de los arcos dentarios, que reproduzcan fielmente todos los detalles anatómicos, para posteriormente obtener un modelo en yeso piedra. Los modelos obtenidos a partir de una impresión generalmente son a base de yeso odontológico, los cuales a pesar de sus mejoras aún conservan algunas características negativas como: baja resistencia a la fractura por impacto, baja resistencia al desgaste por abrasión, inestabilidad dimensional y radiopacidad que impide la simulación de procedimientos endodóncicos. Con la finalidad de mejorar la simulación en la práctica odontológica, se usa la resina epóxica que puede emplearse en la obtención de modelos, este material es más resistente y presenta una mayor resistencia a la abrasión; además es radiolúcido, por lo que es útil para la réplica de preparaciones y procedimientos de simulación endodóntica. Los detalles de la superficie obtenidos con resina epóxica son superiores a los obtenidos con yeso. El uso de simuladores es una herramienta educativa con la que se favorece la adquisición de ciertas habilidades, destrezas, técnicas y competencias necesarias para la formación de estudiantes o profesionales de odontología. En el presente trabajo se describe la técnica para la elaboración de modelos dentales didácticos en resina epóxica para utilizarlos en la enseñanza de la práctica odontológica (AU)

Study studies are a fundamental record for diagnosis, treatment plan, case presentation and evaluation of the progress of dental treatment. They are anatomo-physiological records of the dental arches to evaluate the dentition in the three planes of space and the occlusion in the cusp-fossa relationships, in a static and dynamic dimension. To obtain the study models, it is essential to obtain total impressions with various impression materials of the dental arches, which faithfully reproduce all the anatomical details, in order to later obtain a stone plaster model. Those obtained from an impression are generally based on dental plaster, which despite its improvements still retain some negative characteristics such as: low resistance to fracture by impact, low resistance to wear by abrasion, dimensional instability and radio opacity that prevents the simulation of endodontic procedures. In order to improve simulation in dental practice, the use of epoxy resin can be used to obtain models, this material is more resistant and has greater resistance to abrasion, it is radiolucent, which makes them Useful for replicating preparations and endodontic simulation procedures, the surface details obtained with epoxy resin are superior to those obtained with plaster. The use of simulators is an educational tool that favors the acquisition of certain abilities, skills, techniques and competencies necessary for the training of the student or professional in dentistry. In the present work, the technique for the elaboration of didactic dental models in epoxy resin to be used in the teaching of dental practice is described.(AU)

Modular Digital and 3D-Printed Dental Models with Applicability in Dental Education.

Background and Objectives: The ever more complex modern dental education requires permanent adaptation to expanding medical knowledge and new advancements in digital technologies as well as intensification of interdisciplinary collaboration. Our study presents a newly developed computerized method allowing virtual case simulation on modular digital dental models and 3D-printing of the obtained digital models; additionally, undergraduate dental students' opinion on the advanced method is investigated in this paper. Materials and Methods: Based on the digitalization of didactic dental models, the proposed method generates modular digital dental models that can be easily converted into different types of partial edentulism scenarios, thus allowing the development of a digital library. Three-dimensionally printed simulated dental models can subsequently be manufactured based on the previously obtained digital models. The opinion of a group of undergraduate dental students (n = 205) on the proposed method was assessed via a questionnaire, administered as a Google form, sent via email. Results: The modular digital models allow students to perform repeated virtual simulations of any possible partial edentulism cases, to project 3D virtual treatment plans and to observe the subtle differences between diverse teeth preparations; the resulting 3D-printed models could be used in students' practical training. The proposed method received positive feedback from the undergraduate students. Conclusions: The advanced method is adequate for dental students' training, enabling the gradual design of modular digital dental models with partial edentulism, from simple to complex cases, and the hands-on training on corresponding 3D-printed dental models.

Dental arch changes comparison between Expander with Differential Opening, Hyrax-type and Haas-type expanders: A prospective clinical study.

OBJECTIVE: Compare changes in arch form after RME achieved by Expander with Differential Opening (EDO), Hyrax-type and Haas-type expanders. MATERIALS AND METHODS: Dental models were obtained from 61 patients aged 7-11 years before expansion (T1) and 6 months after the active phase when the appliances were removed (T2). The groups were formed according to the expander used: EDO (n = 18, mean age: 9.46 ± 0.82 years), Hyrax-type (n = 22, mean age: 9.62 ± 1.57 years) and Haas-type (n = 21, mean age: 9.29 ± 1.05 years). The expander`s activation protocol consisted of 7 mm, except for EDO`s anterior screw, which was 9 mm. The measurements of upper and lower intercanine distance, inter-first permanent molar, arch perimeter and length, maxillary canine and first-permanent molar inclination, and palatal depth were performed using the OrthoAnalyzer 3D software. Intergroup comparisons of T1 and between changes (T2-T1) were performed using ANOVA followed by Tukey. RESULTS: In the upper intercanine distance EDO provided a greater increase than Haas-type. In the distance between upper fist permanent molars EDO showed higher values than Haas-type and Hyrax-type. In the lower intercanine distance and maxillary arch length, Haas-type promoted higher increase than EDO. CONCLUSIONS: The EDO promoted greater transverse changes in anterior region than Haas-type and greater transverse changes in posterior region of the maxilla than both conventional expanders. The appliance used for RME influences dental arch changes after treatment; therefore, it is recommended to individualize the choice of expander depending on the clinical necessity of each case.

Accuracy of five different 3D printing workflows for dental models comparing industrial and dental desktop printers.

OBJECTIVES: The aim of this study was to evaluate the accuracy, in terms of trueness and precision, of printed models using five different industrial and dental desktop 3D printers. MATERIALS AND METHODS: Full-arch digital models with scanbodies of 15 patients were printed with five different 3D printers. The industrial printers were 3D system Project MJP2500 (3DS) and Objet30 OrthoDesk (Obj). The dental desktop printers were NextDent 5100 (ND), Formlabs Form 2 (FL) and Rapidshape D30 (RS). A total of 225 printed models were analysed. The printed models were digitized and compared with the reference cast model using the Control X software (Geomagic). The descriptive statistics and one-way ANOVA with the post hoc Tukey test were performed (α = 0.05). RESULTS: The one-way ANOVA for the trueness and precision of the printed model presented the best results for the 3DS, followed by ND, Obj, FL and RS (P < 0.01). In the scanbody zone, the best results were for the 3DS group, followed by Obj, ND, FL and RS (P < 0.01). Comparing the technologies, the Multijet technology used in industrial printers presented better results than the DLP and SLA technologies used in dental desktop printers (P > 0.01). CONCLUSIONS: There were statistically significant differences in terms of the accuracy of the printed models, with better results for the industrial than the dental desktop 3D printers. CLINICAL RELEVANCE: The industrial 3D printers used in dental laboratories presented better accuracy than the in-office dental desktop 3D printers, and this should be considered when the best accuracy is needed to perform final prosthetic restorations.

Comparison of the perception of orthodontists and general clinicians on the use of digital dental models in the city of Aracaju/Sergipe / Comparação da percepção de ortodontistas e clínicos gerais sobre o uso de modelos digitais odontológicos na cidade de Aracaju / Sergipe

ABSTRACT Context: Digital study models have become a safe and advantageous alternative for diagnosis and planning in dentistry. Despite the superior characteristics in comparison with traditional plaster models, professionals seem to resist the use of new technologies. Aims: To assess the level of knowledge and the use of digital models through a questionnaire applied to dental professionals. Methods: A questionnaire with 12 multiple-choice questions about plaster models, digital, and use of the 3Shape - 3D viewer software was answered by 76 orthodontists (42 women and 34 men; mean age =37.82 years (SD ± 7.60)) and 30 general dental surgeons (18 women and 12 men; mean age of 33.93 years (SD ± 8.45)) in Aracaju, Sergipe, Brazil. Data were tabulated in Excel spreadsheets and then analyzed using the SPSS statistical software version 20. An absolute analysis of frequency and percentage of responses was performed. Results: Most professionals reported using plaster models and claimed their low cost as justification for their use (P = 0.001). Aware of the benefits of digital models, professionals of both classes highlighted the facilitated storage and search for information as the main advantages, the cost and infrastructure as the main disadvantages. Regarding the use of the 3Shape - 3D viewer software, orthodontists showed better utilization of this resource than general dental surgeons (P = 0.0198). Conclusion: It verified that most professionals make use of plaster models. However, despite knowing the advantages of digital models, their cost is sees as a limiting factor for adherence to this technology.

RESUMO Contexto: Os modelos digitais de estudo têm se tornado uma alternativa segura e vantajosa para o diagnóstico e planejamento em odontologia. Apesar das características superiores em comparação aos modelos tradicionais de gesso, os profissionais parecem resistir ao uso de novas tecnologias. Objetivos: Avaliar o nível de conhecimento e a utilização de modelos digitais por meio de questionário aplicado a profissionais da área odontológica. Material e Métodos: Questionário com 12 questões de múltipla escolha sobre modelos de gesso, digitais e uso do software 3Shape - 3D viewer foi respondido por 76 ortodontistas (42 mulheres e 34 homens; idade média = 37,82 anos (DP = ± 7,60) ) e 30 cirurgiões-dentistas gerais (18 mulheres e 12 homens; média de idade de 33,93 anos (DP = ± 8,45)) em Aracaju, Sergipe, Brasil. Os dados foram tabulados em planilhas do Excel e posteriormente analisados no software estatístico SPSS versão 20. Foi realizada uma análise absoluta de frequência e percentual de respostas. Resultados: A maioria dos profissionais relatou utilizar modelos de gesso e alegou seu baixo custo como justificativa para seu uso (P = 0,001). Cientes dos benefícios dos modelos digitais, os profissionais de ambas as classes destacaram o armazenamento facilitado e a busca de informações como as principais vantagens, o custo e a infraestrutura como as principais desvantagens. Em relação à utilização do software 3Shape - 3D viewer, os ortodontistas apresentaram melhor aproveitamento desse recurso do que os cirurgiões-dentistas gerais (P = 0,0198). Conclusões: Verificou-se que a maioria dos profissionais faz uso de modelos de gesso. Porém, apesar de conhecer as vantagens dos modelos digitais, seu custo é visto como um fator limitante para a adesão a essa tecnologia.

The Effect of Stacking on the Accuracy of 3D-Printed Full-Arch Dental Models.

The objective of this study was to assess the effect of stacking on the dimensional and full-arch accuracy of 3D-printed models, utilising a standardised assessment methodology. A previously validated methodology involving a standard tessellation language image (STL) reference model, comprising seven spheres on a horseshoe base resembling a dental arch, was used. Six 3D-designed STL models were prepared, optimised, and stacked horizontally using 3D Sprint software. The stacking file was transferred to the NextDent 5100 printer to build the physical models. To assess accuracy, a coordinate measuring machine (CMM) measured the diameter of the spheres n=210, and twenty-one vectors extended between the centres of each of the seven spheres (n = 630). When compared to the reference model, significant differences were observed for dimensional (p = 0.006) and full-arch accuracy (p = 0.006) for all stacked models. Additionally, significant differences were observed between the stacked models for the dimensional accuracy between the posterior (p = 0.015), left posterior (p = 0.005) and anteroposterior (p = 0.002). The maximum contraction was observed in the fourth stacked model, which demonstrated the highest median deviation and least precision within the full-arch (MD = 666 µm, IQR = 55 µm), left posterior (MD = 136 µm, IQR = 12 µm), posterior (MD = 177 µm, IQR = 14 µm) and anteroposterior (MD = 179 µm, IQR = 16 µm) arch segments. In general, the anterior and left posterior arch segments recorded the highest contractions with a median deviation of 34 µm and 29 µm, and precision of 32 µm and 22 µm, respectively. Statistically significant differences were observed between the stacked models in terms of dimensional accuracy that were within clinically acceptable thresholds. The greatest contraction was noted in the fourth model, displaying the least full-arch accuracy compared to the other models. Stacked, additively manufactured, full arch models are a viable alternative for diagnostic, orthodontic, and single-unit prosthodontic applications. In contrast, caution should be exercised when utilising stacked models for full arch high accuracy prosthodontic applications. Further research is needed to assess the impact of additional variables including different printers and resins.

Métodos para medir asimetrías sagitales y transversales en los modelos de estudio de ortodoncia / Methods to measure sagittal and transverse asymmetries in orthodontic study models

Introducción Para el diagnóstico acertado en el tratamiento de los pacientes de ortodoncia se requiere de una serie de exámenes auxiliares, que son herramientas esenciales en ortodoncia; sin embargo, encontramos cierto grado de dificultad para la valoración de asimetrías dentarias en los hemiarcos de cada arcada dentaria; la importancia de la correcta valoración de las asimetrías es ya ampliamente mencionada en diferentes estudios, porque nos ayudará con la localización co-rrecta, de los dientes en su arcada,al final del tratamiento En la actualidad existe poca literatura sobre los métodos para evaluar y diagnosticar las alteraciones por hemiarcos, especialmente en el plano transversal. Objetivo acer una revisión de literatura sobre los métodos de medición de las asimetrías dentarias intra-arco para poder identificar y cuantificar las alteraciones dentarias en los tres planos del espacio en su respectiva arcada dentaria, el Método para los términos de búsqueda de la información fueron: dental and facial asymmetry, molar asymmetry in ortho-dontics, arch width prediction indices, as well as transverse discrepancies, para tal efecto se empleó Pubmed, Medline, Scielo, Schoolar Google, de los cuales se recopilaron 80 artículos relacionados con nuestro tema de estudio y solo se eligieron 30 artículos y 6 libros de ortodoncia en los que se sustenta este artículo. Resultados En el presente artículo presentamos las herramientas con las que contamos para el diagnóstico de la asimetría dentaria intra-arcos como la placa de Sthmuch y la placa milimetrada de Korkhaus, y finalmente proponemos un método que nos permite cuantificar objetivamente la asimetría en los tres plano del espacio de una manera sencilla, reproducible y de fácil almacenaje en un computador. Conclusión La etapa del diagnóstico es importante porque permitirá obtener la mayor y mejor información de las alteraciones dentarias que presenta el paciente, siendo las alteraciones transversales las más difíciles de cuantificar por que la mayoría de los estudios e índices, ya que solo evidencian las distancias de dientes contra laterales, los cuales son datos limitados pero que aún así contribuyen en el diagnóstico, el método de la placa de Sthmuch, Korkhaus y Bernklau son propuesta para medir las asimetrías dentarias intraarcos, no en tanto es desgastador para el operador y sus resultados objetivos radica en la experiencia del operador; el método KLO nos permite cuantificar objetivamente la falta de sime-tría dentaria en cada arcada de una manera fácil, reproducible y de almacenaje en un computador o en un archivo.

Introduction The correct diagnosis in the treatment of orthodontic patients requires a series of auxiliary examinations, which are essential tools in orthodontics, however we found a certain de-gree of difficulty in assessing dental asymmetries in the hemiarchs of each dental arch; The im-portance of the correct assessment of asymmetries is already widely mentioned in different stud-ies, because it will help us with the correct location of the teeth in their arch, at the end of the treatment. Currently there is little literature on the methods to evaluate and diagnose hemiarchal alterations, especially in the transverse plane. Objective Is to review the literature on the methods of measuring intra-arch dental asymmetries in order to identify and quantify dental al-terations in the three planes of space in their respective dental arch. Method The search terms of the information were: dental and facial asymmetry, molar asymmetry in orthodontics, arch width prediction indices, as well as cross-sectional discrepancies. Pubmed, Medline, Scielo, Schoolar Google, of which 80 articles related to our study topic were collected and only 30 articles and 6 orthodontic books were chosen on which this article is based, Results Also in this article we present the tolos that we have for the diagnosis of intraarch dental asymmetry such as the Sth-much plate and the Korkhaus millimeter plate, and finally we propose a method that allows us to objectively quantify the asymmetry in the three space plan in a simple, reproducible way and easy to store on a computer. Conclusión The stage of diagnosis is important because it will allow obtain-ing the greatest and best information on the dental alterations that the patient presents, being the transversal alterations the most difficult to quantify because most studies and indices, since they only show the distances of Contralateral teeth, which are limited data but still contribute to the diagnosis, the Sthmuch, Korkhaus and Bernklau plate method are proposed to measure intra-arch dental asymmetries, not as it is wearisome for the operator and his patients. objective results lies in the experience of the operator; The KLO method allows us to objectively quantify the lack of dental symmetry in each arch in an easy, reproducible way that can be stored on a computer or in a file.

Evaluation of an open access generic 3D software for Orthodontic diagnosis and treatment planning

Aim: To evaluate the accuracy and the validity of orthodontic diagnostic measurements, as well as virtual tooth transformations using a generic open access 3D software compared to OrthoAnalyzer (3Shape) software; which was previously tested and proven for accuracy. Methods: 40 maxillary and mandibular single arch study models were duplicated and scanned using 3Shape laser scanner. The files were imported into the generic and OrthoAnalyzer software programs; where linear measurements were taken twice to investigate the accuracy of the program. To test the accuracy of the program format, they were printed, rescanned and imported into OrthAnalyzer. Finally, to investigate the accuracy of editing capabilities, linear and angular transformation procedures were performed, superimposed and printed to be rescanned and imported to OrthoAnalyzer for comparison. Results: There was no statistically significant difference between the two groups using the two software programs regarding the accuracy of the linear measurements (p>0.05). There was no statistically significant difference between the different formats among all the measurements, (p>0.05). The editing capabilities also showed no statistically significant difference (p>0.05). Conclusion: The generic 3D software (Meshmixer) was valid and accurate in cast measurements and linear and angular editing procedures. It can be used for orthodontic diagnosis and treatment planning without added costs

Three-dimensional digital applications for implant space planning in orthodontics: A narrative review.

In the digital dentistry era, new tools, algorithms, data science approaches, and computer applications are available to researchers and clinicians. However, there is also a strong need for better knowledge and understanding of multisource data applications, including three-dimensional imaging information such as cone-beam computed tomography images and digital dental models for multidisciplinary cases. In addition, artificial intelligence models and automated clinical decision systems are rising. The clinician needs to plan the treatment based on state-of-the-art diagnosis for better and more personalized treatment. This article aimed to review basic concepts and the current panorama of digital implant planning in orthodontics, with open-source and closed-source tools for assessing cone-beam computed images and digital dental models. The visualization and processing of the three-dimensional data allow better implant planning based on bone conditions, adjacent teeth and root positions, and the prognosis of the case. We showed that many tools for assessment, segmentation, and visualization of cone-beam computed tomographic images and digital dental models could facilitate the treatment planning of patients needing implants or space closure. The tools and approaches presented are toward personalized treatment and better prognosis, following the path to a more automated clinical decision system based on multisource three-dimensional data, artificial intelligence models, and digital planning. In summary, the orthodontist needs to analyze each patient individually and use different software or tools that better fit their practice, allowing efficient treatment planning and satisfactory results with an adequate prognosis.

Comparison in Terms of Accuracy between DLP and LCD Printing Technology for Dental Model Printing.

BACKGROUND: The aim of this study is to evaluate the accuracy of a Liquid Crystal Display (LCD) 3D printer compared to a Direct Light Processing (DLP) 3D printer for dental model printing. METHODS: Two different printers in terms of 3D printing technology were used in this study. One was a DLP 3D printer and one an LCD 3D printer. The accuracy of the printers was evaluated in terms of trueness and precision. Ten STL reference files were used for this study. For trueness, each STL file was printed once with each 3D printer. For precision, one randomly chosen STL file was printed 10 times with each 3D printer. Afterward, the models were scanned with a model scanner, and reverse engineering software was used for the STL comparisons. RESULTS: In terms of trueness, the comparison between the LCD 3D printer and DLP 3D printer was statistically significant, with a p-value = 0.004. For precision, the comparison between the LCD 3D printer and the DLP 3D printer was statistically significant, with a p-value = 0.011. CONCLUSIONS: The DLP 3D printer is more accurate in terms of dental model printing than the LCD 3D printer. However, both DLP and LCD printers can accurately be used to print dental models for the fabrication of orthodontic appliances.