Research On The Path Planning For Orthodontics In Invisalign Technique

Having a neat set of white teeth can make people feel more confident.Cater to the modern people aesthetic concept of life,dental health is gradually being taken seriously.The cross integration of computer aided design and stomatology makes invisalign technique a hot topic of research.The invisalign orthodontics technique can predict orthodontic results.How to automatically calculate the pose of intermediate stages of orthodontic teeth is the key point of this orthodontic technique.To solve this problem,this thesis is divided into two parts for the orthodontic path planning problem.Aim at the ideal orthodontic position and posture of the teeth problem.Define the dental posture using Euler angles,an automatic alignment of malocclusion based on fitting optimization is proposed in this paper.Analyze the position and posture of teeth in the dentition at two dimensional,weighted fitting optimization method was employed to calculate the coordinate translation and local axis rotation of tooth,acquiring association constraints of position and posture of tooth and spatial dental curves.Then,combined with rectangular bounding box collision detection method,we design an iterative algorithm based on method of steepest descent to adjust teeth within the constraints of spatial dental curves.Finally,validate the effectiveness of the algorithm through experiments.At the same time,the method was compared with the methods of manual artificial tooth extraction and existing tooth arrangement,and the experimental results and analysis were given.Focus on the orthodontic path planning problem.Using the quaternion to define the tooth posture,combined with the initial pose of the tooth and the target pose,it is divided into two steps to determine conflict-free paths for teeth moving in three dimensions space.In the first step,the quaternion spherical linear interpolation and position linear interpolation are used to obtain the median orthodontic tooth position and posture,we can get the initial orthodontic stages,and the result of intermediate posture will be as a sampling node applied to the next step.In the second step,considering orthodontic collision interference problems,a method for defining orthodontic priorities is proposed to obtain teeth movement sequence,and improve the random node extension in the RRT(Rapid-exploration Random Tree)algorithm,a random tree of orthodontic nodes is obtained for iterative with the orthodontic stage of first step is the iterative initial value.Finally,a path with no collision and the least number of orthodontic phases is searched from the random tree of each tooth node.The experimental results and analysis show that this method can quickly and efficiently solve Orthodontics path.