A pilot study to assess the feasibility and accuracy of using haptic technology to occlude digital dental models.

Objectives: The use of haptic technology as an adjunct to clinical teaching is well documented in medicine and dentistry. However its application in clinical patient care is less well documented. The aim of this pilot study was determine the feasibility and accuracy of using a haptic device to determine the occlusion of virtual dental models. Methods: The non-occluded digital models of 20 pre-treatment individuals were chosen from the database of Faculty of Dentistry, The University of Hong Kong. Following minimal training with the haptic device (Geomagic® TouchTM), the upper model was occluded with the lower model until a stable occlusion was achieved. Seven landmarks were placed on each of the corners of the original and haptically aligned upper model bases. The absolute distance between the landmarks was calculated. Intra- and inter-operator errors were assessed. Results: The absolute distance between the 7 landmarks for each original and corresponding haptically aligned model was 0.54 ± 0.40mm in the x-direction (lateral), 0.73 ± 0.63mm in the y-direction (anterior-posterior) and 0.55 ± 0.48mm in the z-direction (inferior-superior). Conclusion: Based on initial collision detection to prevent interpenetration of the upper and lower digital model surfaces, and contact form resistance during contact, it is possible to use a haptic device to occlude digital study models

3D orthodontics visualization

Master'sMASTER OF ENGINEERIN

A semi-automatic computer-aided method for surgical template design

This paper presents a generalized integrated framework of semi-automatic surgical template design. Several algorithms were implemented including the mesh segmentation, offset surface generation, collision detection, ruled surface generation, etc., and a special software named TemDesigner was developed. With a simple user interface, a customized template can be semi- automatically designed according to the preoperative plan. Firstly, mesh segmentation with signed scalar of vertex is utilized to partition the inner surface from the input surface mesh based on the indicated point loop. Then, the offset surface of the inner surface is obtained through contouring the distance field of the inner surface, and segmented to generate the outer surface. Ruled surface is employed to connect inner and outer surfaces. Finally, drilling tubes are generated according to the preoperative plan through collision detection and merging. It has been applied to the template design for various kinds of surgeries, including oral implantology, cervical pedicle screw insertion, iliosacral screw insertion and osteotomy, demonstrating the efficiency, functionality and generality of our method.Comment: 18 pages, 16 figures, 2 tables, 36 reference

Technology-enhanced simulation-based learning in orthodontic education: A scoping review

ABSTRACT Introduction: Technology-enhanced simulations seem to be effective in dentistry, as they can support dental students to improve competencies in simulated environments. However, implementation of this technology in orthodontic education has not been reviewed. Objective: This scoping review aimed to comprehensively summarize the use of technology-enhanced simulations in orthodontic practice. Methods: A systematic search was conducted to identify literature on technology-enhanced simulation-based learning in orthodontic education published from 2000 to 2021. The search was conducted up to September 2021 to identify articles from Scopus, Embase, PubMed, ProQuest Dissertations & Theses Global, Google Scholar and the reference lists of identified articles. Results: The search identified 177 articles. Following the inclusion and exclusion criteria, 16 articles of 14 digital simulators were included in this review. The findings demonstrated an increasing use of technology-enhanced simulations in orthodontic education. They were designed in several formats, including three-dimensional virtual format, augmented reality, virtual reality, automaton, haptic, and scenario-based simulations. These simulations were implemented in varied areas of orthodontics including diagnosis and treatment planning, bracket positioning, orthodontic procedures, facial landmark, removable appliance and cephalometric tracing. Most included articles demonstrated the development process without outcome evaluation. Six studies provided outcome evaluations at reaction or learning levels. None of them provide the evaluation at behaviour and results levels. Conclusion: Insufficient evidence has been generated to demonstrate the effectiveness of technology-enhanced simulations in orthodontic education. However, high-fidelity computer-based simulations together with robust design research should be required to confirm educational impact in orthodontic education

Digital dental splints in orthognathic surgery and evaluation of their accuracy of fit in an anatomically articulated model

PURPOSE: The purpose of this prospective clinical study is to evaluate the accuracy of fit of digital dental splints in an anatomically articulated model on which model surgery is performed. The intermediate 3D printed splints were verified in an anatomical articulator. MATERIALS AND METHODS: A total of 4 patients (Table 1,2) who were willing to undergo orthognathic surgery (Graph 2) were included in this study. The methodology of the study were as follows: A Cone Beam Computed Tomography scan was obtained with fiducial titanium markers of standardized dimensions glued to the attached gingiva (Figure 57) for all patients excluding one patient for whom a medical Computed Tomography scan was taken. The upper and lower impressions were made, and models prepared (Figure 58). These dental casts were scanned with an optical scanner and the digital dental casts were saved as stl files (Figure 56 A, B). The CBCT scans and the digital dental scans were imported into MIMICS software (Version 17.0 Leuven, Belgium). Planned virtual osteotomy was performed virtually on the 3D reconstructed models after accurate superimposition based on the fiducial titanium markers (Figure 30,31). Intermediate splints were virtually designed (Figure 36,37,38), and 3D printed by importing into 3D printer (Inkjet printing) in our study. RESULTS: Out of the four patients, one patient with Hemifacial Microsomia had extensive bleeding during a medial cut on the mandibular ramus due to which the planned mandibular surgery was not performed. One patient was previously treated for temporomandibular joint ankylosis, who had no complications intra-operatively during orthognathic surgery. The fit of the digital dental splint was subjectively superior to the conventional acrylic splints and therefore was clinically more acceptable. CONCLUSION: The results of this study indicates that virtual planning and 3D printing of the intermediate splints have the following advantages: 1. An overall decrease in the time required for conventional planning in orthognathic surgery. 2. Aids in better understanding of the existing deformity in all dimensions. 3. Ensures more accuracy in splint fabrication, aiding in superior precision in positioning of the osteotomized segments. 4. Minimizes the errors due to conventional two-dimensional radiographs. 5. The use of fiducial markers in our study makes the superimposition process more accurate and avoids inaccuracies due to superimposition

Haptics-based Modeling and Simulation of Micro-Implants Surgery

Ph.DDOCTOR OF PHILOSOPH

Issues in Contemporary Orthodontics

Issues in Contemporary Orthodontics is a contribution to the ongoing debate in orthodontics, a discipline of continuous evolution, drawing from new technology and collective experience, to better meet the needs of students, residents, and practitioners of orthodontics. The book provides a comprehensive view of the major issues in orthodontics that have featured in recent debates. Abroad variety of topics is covered, including the impact of malocclusion, risk management and treatment, and innovation in orthodontics

Segmentation of the Oral and Facial Regions from Imaging Modalities with Reduced or No Ionizing Radiation

Ph.DDOCTOR OF PHILOSOPH