Browsing by Author "Chanjira Sinthanayothin"

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    Assessment of the accuracy and reliability of cephsmile v.2 in cephalograms and model measurements
    (2012-02-20) Orrathai Watcharinporn; Surachai Dechkunakorn; Niwat Anuwongnukroh; Chanjira Sinthanayothin; Peerapong Santiwong; Wisarut Bholsithi; Wanna Suchato; Mahidol University; Thailand National Electronics and Computer Technology Center
    Objective: The study compared the measurement values from lateral cephalometric analysis, postero-anterior cephalometric analysis and study models between CephSmile version 2.0 and hand-traced method. Materials and Methods: Thirty sets of digital lateral, postero-anterior cephalograms and plaster models were selected randomly, uploaded and measured with CephSmile version 2.0 Program. All dental measurements were compared with manual measurements. Manual cephalometic measurements were obtained with a cepholomatic protractor and model measurements with vernier calipers. Both groups were assessed for accuracy and reliability. Mean and SD were calculated using SPSS version 11.0. Results: All CephSmile and hand-traced radiograph coefficients of variation were less than 0.10 suggesting high interexaminer reliability. No significant differences were found comparing lateral cephalograms, postero-anterior cephalograms, and plaster models between manual measurements and CephSmile Program version 2.0. Conclusion: CephSmile Software version 2.0 is as accurate and reliable as manual measurements for cephalometric analysis in orthodontic clinical treatment and planning. © 2012 Springer-Verlag GmbH.
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    Comparison of digitized images for cephalometric analysis from scanner and digital cameras
    (2011-09-23) Niwat Anuwongnukroh; Surachai Dechkunakorn; Chanjira Sinthanayothin; Lada Shinawatra.; Mahidol University; Thailand National Electronics and Computer Technology Center
    Objective: The aim of the study was to compare the manual tracing of lateral cephalometric radiographs with the use of cephalometric software obtained by 2 methods: use of a scanner and use of cameras to test the accuracy of measurement for clinical orthodontic diagnosis. Material and Methods: The original method of manual tracing was compared to 2 radiographic digitization methods: A) captured from a scanner, B) captured from digital cameras applied to 40 randomly selected cephalograms of orthodontic patients at Mahidol University. The digital images from cameras and scanner were analyzed with image processing software (CephSmile). The repeatability test was obtained for all methods, and the paired t-test determined the statistical significance between digitized images and original manual tracings for thirty-four measurements. Results: The paired t-test showed no significant differences among all 34 variables. Most mean differences were less than 0.25 mm and 0.25 degrees. Conclusion: The results demonstrated that there were no significant differences on measurement parameters for cephalometric analysis among manual tracing and computerized digital images from scanner and cameras. © (2011) Trans Tech Publications.
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    Point-cloud-to-point-cloud technique on tool calibration for dental implant surgical path tracking
    (2008-06-18) Auranuch Lorsakul; Jackrit Suthakorn; Chanjira Sinthanayothin; Mahidol University; Thailand National Science and Technology Development Agency
    Dental implant is one of the most popular methods of tooth root replacement used in prosthetic dentistry. Computerize navigation system on a pre-surgical plan is offered to minimize potential risk of damage to critical anatomic structures of patients. Dental tool tip calibrating is basically an important procedure of intraoperative surgery to determine the relation between the hand-piece tool tip and hand-piece's markers. With the transferring coordinates from preoperative CT data to reality, this parameter is a part of components in typical registration problem. It is a part of navigation system which will be developed for further integration. A high accuracy is required, and this relation is arranged by point-cloud-to-point-cloud rigid transformations and singular value decomposition (SVD) for minimizing rigid registration errors. In earlier studies, commercial surgical navigation systems from, such as, BrainLAB and Materialize, have flexibility problem on tool tip calibration. Their systems either require a special tool tip calibration device or are unable to change the different tool. The proposed procedure is to use the pointing device or hand-piece to touch on the pivot and the transformation matrix. This matrix is calculated every time when it moves to the new position while the tool tip stays at the same point. The experiment acquired on the information of tracking device, image acquisition and image processing algorithms. The key success is that point-to-point-cloud requires only 3 post images of tool to be able to converge to the minimum errors 0.77%, and the obtained result is correct in using the tool holder to track the path simulation line displayed in graphic animation.
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    Toward robot-assisted dental surgery: Path generation and navigation system using optical tracking approach
    (2008-12-01) Auranuch Lorsakul; Jackrit Suthakorn; Chanjira Sinthanayothin; Wichit Tharanon; Mahidol University; Thailand National Science and Technology Development Agency
    The main aim of this paper is to develop dental implant surgical navigation system based on homogenous transformation algorithms. This work is a partial section of robot-assisted surgical development. The previous works are presented in numerous basic research. They are methodology design on tool tip calibration, optical marker recognition, and pose determination using neural networks. This paper concerns with tracking path generation system based on fundamental of optical tracking. The intraoperative system is the principal focus area of this study. The homogenous transformation has been calculated in term of kinematics equation among marker relationship. The stereo camera is utilized to retrieve 3D position of different pattern styles of markers. The beneath marker recognition algorithm using rotation-invariant neural network and physical method is performed to identify markers. The fundamental relationship among markers are computed to obtain the orientation and translation between the guided path and the instrument's tool tip. The experiment has been demonstrated and performed under prototype model. The method is to work on procedure step by step. They begin with patient information input and continuously perform on marker recognition, tool tip calibrations and marker digitization. The path tracking is executed to observe the accuracy of the system. The result shows that the system can be performed to track path based on beforehand planning. © 2008 IEEE.