Design Of A Surgical Simulator For Root Canal Preparation Training Based On Virtual Reality

With the improvement in healthcare,the skill requirement of clinical staff has become more and more highly.A lengthy and repetitive surgical training would be inevitable in the course of transformation,which is from students to clinical doctors.As a novel training teaching system,virtual surgery has solved a series of problems in the training of clinical staff.To improve the efficiency of skills training which is gone on for root canal preparation to dental students,research on the design of a surgical simulator for root canal preparation training based on virtual reality has been described in this paper.Firstly,requirement analysis of the training system has been processed according to the essential of root canal preparation surgery and the traditional training method,to design a virtual surgical simulator for root canal preparation training.At the same time,to make sure the system real-time,a software scheme has been designed based on multi-thread in the paper,that achieves visual image rendering by OpenGL,which is a graphic programming library with high portability and strong expansibility,and achieves force-feedback haptics by HDAPI,which is the nearest part to the force-feedback device in the OpenHaptics Toolkit.Secondly,to build and control the virtual scene,work of the management and searching about 3D model’s data has been done.That is a simplification to the traditional AIF method,by keeping two graphic elements Vertex and Face only,to construct the topology of graphic elements in the 3D model of the tooth.On the other hand,the unified management of space coordinates system,space pose scene’s coordinate projection transformation and 3D’s kinematic operator used a homogeneous matrix.And it has completed the view angle transforming in the virtual scene and coordinates mapping between virtual scene and interact device in the paper.Thirdly,based on orienting vertex and triangular patch,two collision-detecting methods have been designed to complete the collision detection of the tanglesome tooth’s model accurately and real-timely.And an optimization algorithm based on space octree has been taken to make sure the collision-detecting method real-time.Preliminary tests showed that the level of accurately and real-timely is satisfactory in both methods.And the optimization algorithm worked obviously.Finally,the feed-back force has been computed by the God-Object method in the virtual system of root canal preparation surgery.Based on the principle of bar’s bending moment,a method of bend-shaping dynamic control on the model of rod-shaped tool has been designed.It achieves the bend-shaping physical property simulating from the root canal file model,which is the tool in root canal preparation surgery.To simulate the shaping of tooth model,a method has been signed based on energy erosion,which used work of friction to corrode the energy of tooth’s vertex.The test experiment showed the three methods could simulate the physical property effectively.And they are in favour of the level of realism of the simulator.