Investigation of coronoid process impingement by efficient collision detection method in real time mandibular movement simulation

Presentation 0811, Dental Biomechanics and Finite Elements. 11:00, Room 101B

S462

Investigation of coronoid process impingement by efficient collision detection method in real time mandibular movement simulation 1

T.C. Wu , J.J. Fang1, T.Y. Wong2, J.M.Ritchie3, J.Corney3, T.Lim3, J.Simmons3 1

Department of Mechanical Engineering, National Cheng Kung University, Taiwan 2

Institute of Oral Medicine, National Cheng Kung University, Taiwan

3

Department of Mechanical Engineering, Heriot-Watt University, UK INTRODUCTION Coronoid process impingement (CPI) can be caused by coronoid process hyperplasia, tumor in posterior maxilla, or depressed fracture in zygoma. The difficulty reason of CPI diagnosis is due to lack of three-dimensional moving information between moving jawbones. In this study, we Figure 2. Bounding spheres schema present an efficient collision detection method to distinguish organ impingement from free impingement, subsequently, RESULTS AND DISCUSSION soft impingement from hard impingement. Furthermore, a The efficient detection method is applied to eight number of occlusion difficulty cases are investigated by this FDVHV RI PRXWK RSHQLQJ GLIILFXOW\ 6\PEROV µ¶DQG µ-¶in method. table 1 denote hard and soft impingement, respectively. Via Keywords: Coronoid process impingement, Mandibular computer simulation, list in table 1, the first five cases are symptom of OSF, the cases 6 and 7 are ZMF, and the case 8 movement, Collision detection method is CPH. In movement II, the coronoid process approaches METHODS and closes to the zygomatic bone in every case. The There are two primary causes for coronoid process movement II simulation reveals that hard impingement takes impingement. Firstly, the hyperplaisa or enlargement of the place at cases 4 and 7 at the position of mouth opening coronoid process, which may be idiopathic or secondary to 17mm and 15mm, respectively. the prolonged restricted mouth opening situation initiated by some other diseases such as TMJ ankylosis or internal Table 1. CPI diagnosis application derangement. Secondly, zygoma fractures due to external Case-Symptom Movement I Movement II force striking, which may cause opening movement difficulty at the collision point between zygomatic bone and CPI Nearest CPI Nearest coronal process. However, in case the open-mouth dist.(mm) dist.(mm) tomography shows interference on one side only, it is not 1-OSF 9.69 6.57 known whether the impingement will take place on the other 2-OSF 6.72 4.3 side following a unilateral surgical treatment. In this study, we simulate mouth movement of open-close by 3-OSF 5.61 2.43 reconstructed mandibular models. Efficient collision 4-OSF 6.8 + 0 detection method is involved to reveal the minimal distance between two objects. Therefore, reasons of causing CPI can 5-OSF 3.74 2.86 be diagnosed. 6-ZMF 5.8 4.38 In this paper, we present two movement models. 7-ZMF 2.64 + 0 Movement I defines a pure rotation along a defined axis. Movement II diagram in Figure 1 illustrates a pure rotation 8-CPH 4.3 2.4 subsequent to a short distance sliding. Since the model CONCLUSIONS objects are reconstructed from computer tomography in 1mm slicing, therefore, it consists of enormous number of In this study, we propose two types of impingements for triangulated structures with merely 0.3 mm edge each. It was mouth open difficulty diagnosis. An efficient method of defined that the distance between coronoid process and impingement judgment promotes medical diagnosis zygomatic bone less than either 2mm or 0mm represents soft technique in two types of mouth open-close movements. (tissue) impingement or hard (bone) impingement, Currently, the process has been applied to eight individuals respectively. For the purpose of simultaneously illustrate and distinguish impingement type an efficient way of bounding complaining mouth open difficulty. Resultant suggests that spheres method is applied to detect impingement types. two of the eight cases need advanced surgery in coronoid In order to improve distance calculation performance, we process osteotomy. adapt bounding sphere method to represent each triangular. REFERENCES As shown in Figure 2, distance between two bounding 1. J.J. Fang, D.E.R. Clark, J.E.L. Simmons, June, 1995, spheres can judge the type of impingement or not ³&ROOLVLRQ 'HWHFWLRQ 0HWKRGRORJLHV IRU 5LJLG %RG\ impingement occurs. $VVHPEO\LQD9LUWXDO(QYLURQPHQW´-RXUQDORI9LUWXDO Reality Society, Vol. 1, No. 1, pp. 41-48. 2. J.J. Fang, D.E.R. Clark and J.E.L. Simmons, December, 1995, "An Accurate Collision Detection Method for Virtual Assembly and Locking," Proceedings of Framework for Immersive Virtual Environments - FIVE'95, pp. 151-162, London. Figure 1. Movement II

Journal of Biomechanics 40(S2)

ACKNOWLEDGEMENTS The study is supported by National Science Council in Taiwan, NSC 94-2314-B-006-068-. XXI ISB Congress, Podium Sessions, Thursday 5 July 2007