The paper presents the creation of a dental bridge through two rapid prototyping technologies, SLA and FDM. The dental bridge model was made in a dental laboratory, being used later for 3D printing, ...through rapid prototyping, using the two technologies, FDM and SLA.
Although 3D-printing is common in dentistry, the technique does not produce the required quality for all target applications. Resin type, printing resolution, positioning, alignment, target ...structure, and the type and number of support structures may influence the surface roughness of printed objects, and this study investigates the effects of these variables. A stereolithographic data record was generated from a master model. Twelve printing processes were executed with a stereolithography Desktop 3D Printer, including models aligned across and parallel to the printer front as well as solid and hollow models. Three layer thicknesses were used, and in half of all processes, the models were inclined at 15°. For comparison, eight gypsum models and milled polyurethane models were manufactured. The mean roughness index of each model was determined with a perthometer. Surface roughness values were approximately 0.65 µm (master), 0.87-4.44 µm (printed), 2.32-2.57 µm (milled), 1.72-1.86 µm (cast plaster/alginate casting), and 0.98-1.03 µm (cast plaster/polyether casting). The layer height and type and number of support structures influenced the surface roughness of printed models (
≤ 0.05), but positioning, structure, and alignment did not.
Objectives
This study investigated the application of an intraoral banana peel suturing model in helping students to acquire intraoral surgical techniques.
Methods
This is a self‐control study ...conducted from January 2021 to March 2021. An intraoral banana peel suturing model was implemented to provide oral suture experience for undergraduates majoring in stomatology. The sutures students placed in the model were photographed and evaluated blindly by a professional team using an established scoring system. Training scores were recorded before (training 1) and after 2 months of training (training 2). Linear regression was used to examine factors related to the scores. Suturing training was conducted in the School and Hospital of Stomatology at Peking University. A total of eighty‐two students in Peking University School and Hospital of Stomatology were in their fourth pre‐clinical year and followed a workshop on surgical sutures according to the curriculum. All students who should take this course were included, and the response rate was 100%.
Results
The mean training 2 score (23.04 ± 3.83) was higher than the mean training 1 score (13.94 ± 3.15). The training 1 score was not significantly correlated with any of the students' general characteristics. The training 2 score was correlated with the training 1 score and the cumulative duration of practice outside of class.
Conclusion
The intraoral banana peel suturing model can be used for suture training, and dental students’ suture ability was improved after using the banana peel for suture practice.
Background: Due to advances in digital technology, it is possible to obtain digital dental models through intraoral scanning. The stereolithographic data collected from the scanner can subsequently ...be printed into a three-dimensional dental model in resinic material. However, the accuracy between digital dental models and printed dental models needs to be evaluated since it might affect diagnosis and treatment planning in orthodontic treatment.
This study aimed to evaluate the accuracy of digital models scanned by a Trios intraoral scanner and three-dimensional dental models printed using a Formlabs 2 3D printer in linear measurements and Bolton analysis.
Methods: A total of 35 subjects were included in this study. All subjects were scanned using a Trios intraoral scanner to obtain digital study models. Stereolithographic data from previous scanning was printed using a Formlabs 2 3D printer to obtain printed study models. Mesiodistal, intercanine, intermolar, and Bolton analysis from all types of study models were measured. The intraclass correlation coefficient was used to assess intraobserver and interobserver reliability. All data were then statistically analyzed.
Results: The reliability tests were high for both intraobserver and interobserver reliability, which demonstrates high reproducibility for all measurements on all model types. Most of the data compared between study models showed no statistically significant differences, though some data differed significantly. However, the differences are considered clinically insignificant.
Conclusion: Digital dental models and three-dimensional printed dental models may be used interchangeably with plaster dental models for diagnostic and treatment planning purposes.
Keywords: Accuracy, 3D printing, digital dental model, printed dental model.
Automatic teeth segmentation and labeling on dental models are basic tasks in computer-aided dentistry. Many existing works can achieve promising results in teeth segmentation, but they heavily rely ...on aligned input dental models, which leads to additional manual intervention. Moreover, tooth labeling is an essential task in digital dentistry for treatment planning ( e.g. , orthodontic), and is usually ignored in these methods. In this article, we propose an AlignNet for aligning dental models of arbitrary sizes and orientations automatically. Meanwhile, a multi-task hybrid learning network is designed that effectively plays the advantages of semantic segmentation and instance segmentation, and synergistically improves the performance of teeth point clouds segmentation and labeling. Particularly, for the teeth-gingival boundaries with large segmentation errors, we utilize the filtered curvature information as a constrained feature to detect the weak boundary more accurately. At last, we propose a DiffLoss and postprocessing step based on the dental arch to address the teeth classification problem. Through extensive evaluations of oral scanning models, our method is robust to handle dental model point clouds with arbitrary size and orientation, and outperforms state-of-the-art teeth segmentation and labeling methods, demonstrating its full automation and robustness in clinical practice.
•We have proposed a graph attentional convolution network for 3D dental model segmentation.•We have proposed a local spatial augmentation module that can adaptively capture the local structure of ...dental model.•We have designed a learning-based graph attention mechanism to learn local geometric features from dental model.•We achieved best segmentation performance on a real-patient dataset when compared with state-of-the-art methods for 3D shape segmentation.
Precisely segmenting teeth from digitized 3D dental models is an essential task in computer-aided orthodontic surgical planning. In recent years, various deep learning-based methods have been proposed to process dental models for teeth segmentation, however, these methods usually ignore or coarsely model the dependency between vertices/mesh cells in local space, which fails to exploit local geometric details that are critical to capture complete teeth structure. In this paper, we propose a specific end-to-end network for teeth segmentation on 3D dental models. By constructing a graph for the raw mesh data, our network adopts a series of graph attentional convolution layers and a global structure branch to extract fine-grained local geometric feature and global feature, respectively. Subsequently, these two features are further fused to learn comprehensive information for cell-wise segmentation tasks. We have evaluated our network on a real-patient dataset of dental models acquired through 3D intraoral scanners, and experimental results show that our method outperforms state-of-the-art deep learning methods for 3D shape segmentation.
This study investigated the effectiveness of simulation training in improving the confidence and competency of oral and maxillofacial surgery (OMS) residents in performing orthognathic surgery (OGS).
...Kern's six-step approach was applied when designing the simulation training for OMS residents. The difficulties encountered by the residents when learning OGS were considered when designing the training program. A training course consisting of didactic sessions, hands-on training on three-dimensional training models, and an assessment tool was implemented for OMS residents. Improvement in the confidence and competence of OMS residents in performing OGS, fidelity of the three-dimensional models, and satisfaction with the course was evaluated.
All OMS residents (10/10) completed the course. The perceived difficulty in learning OGS was mainly related to the manipulation of the jawbones. While there were improvements in the median confidence and competence scores (3/5 to 4/5), only the differences in competence were found to be statistically significant (p < 0.01, Wilcoxon signed-rank test). Improvements in confidence and competence did not correlate. The mean fidelity scores of both the maxillary and mandibular models were adequate at 3.2 out of 5. Overall, satisfaction with the course was high (5/5).
The six-step approach provides a guided process for educators to formulate a training course directed toward the perceived needs of students. Targeted training can significantly enhance the students' competence. Greater efforts should also be put in place to allow simultaneous developments in the students' confidence along with their competence.
Objectives: This study aims to compare the measurements of the extraction spaces in the plaster models and digital dental models and to investigate the usability of the digital models in preventive ...and interceptive appliances in pediatric dentistry clinics.Material and Methods: In the dental models of 56 patients whose first molar teeth were extracted in the early period, the dental arch length of the extraction spaces were measured with a digital caliper in the plaster model (Control Group), with computer software in the digital model (Experimental Group). Measured values were compared using a t-test and statistical significance levels were determined.Results: In plaster models and digital models, the measured mean arc length of the extraction spaces were 6.94 mm and 6.83 mm, respectively. There was no statistically significant difference between the two measurement methods (p>0.05). Conclusions: The use of digital models is recommended in pediatric dentistry clinics due to shorter chair time in pediatric patients, effective treatment planning/follow-ups, reducing treatment costs and other advantages.
•We introduce a novel implicit-function-based approach for 3D shape synthesis.•We demonstrate this approach can successfully generate realistic complete dental models from partial inputs.•We validate ...our approach qualitatively and quantitatively by extensive experiments against the state-of-art methods.
While complete dental models are crucial for digital dentistry, current technologies mostly focus on the 3D dental crown but overlook the dental gum that is important for applications in orthodontics and prosthodontics. To reconstruct the complete dental models with visually realistic geometry from the given crown data, we propose to combine the implicit function representation with the self-attention mechanism. Recent studies have shown that the implicit function is an effective 3D representation for shape completion. However, existing methods fail in dealing with dental models with complex shapes and details, because the convolution and linear operations adopted in their networks are inefficient for modeling long-range dependencies or hard to maintain detailed geometry of the shapes. Therefore, we propose to introduce self-attention to the implicit function network for the first time and use it to effectively capture non-local features at different levels. Extensive ablation studies were conducted to validate the efficiency of our method. Quantitative and qualitative comparisons demonstrate that the feature extracted by our network is more expressive and thus leads to better dental model completion and reconstruction results.
PDF
