Dental modeling system and method

Abstract

A method for simulating tooth movement utilizes electronic modeling to represent the teeth. Instant centers of rotation are determined and projected paths of movement are plotted. The electronic model provides improved precision and provides a method for simulating movement in three dimensions. The movement from growth and/or correction is shown with the electronic model. The simulation provides for improved correction.

1 . A method of modeling tooth movement of a patient, comprising: creating a first virtual model of the patient's teeth;
 identifying a first reference point on a first virtual tooth of the model; identifying a second reference point on the patient's mandible; creating a second virtual model of the patient's teeth after a time period;   tracking the movement of the first reference point from a first location to a second location over the time period;   tracking the movement of the second reference point from a third location to a fourth location over the time period; extending a first segment between the first location and the second location;   extending a second segment between the third location and the fourth location; projecting a first perpendicular bisector from the first segment; projecting a second perpendicular bisector from the second segment;   determining an intersection of the first and second bisectors, defining a rotational axis;   plotting an arc centered on the rotational axis along which the first reference point will travel.   
   
   
       2 . A method according to  claim 1 , wherein the computer projects tooth movement in the future and creates a third virtual model representing a future tooth position. 
   
   
       3 . (canceled) 
   
   
       4 . A method of modeling a patient's tooth movement on linkage configurations, comprising:
 defining a ground point axis of rotation;   adopting a first point on the patient's ramus as a first link pivot;   adopting a second point on one of the patient's lower teeth as a second link pivot;   tracing a first path of the first point pivoting about the axis of rotation, tracing a second path of rotation about the axis of rotation pivoting about the axis of rotation;   moving the first point along the first path a first distance;   applying a relative movement factor to the first distance to determine a second distance between the first point and the second point;   moving the second point along the second path until the second point is the second distance from the first point to arrive at a predicted location.   
   
   
       5 . A method according to  claim 4 , wherein the linkage is oriented with virtual modeling. 
   
   
       6 . A method according to  claim 4 , wherein the ground point axis of rotation is determined with virtual models. 
   
   
       7 . A method according to  claim 4 , growth factor to determine distance between two pivots. 
   
   
       8 . A method according to  claim 4 , wherein coefficient of relative growth is applied to the first distance to determine the second distance. 
   
   
       9 . A method according to  claim 4 , further adopting a segment connecting the axis of rotation and the first point as the first link;
 adopting and a segment connecting the axis of rotation and the second point as the second link;   rotating the first point along the first path a first angle;   applying a relative movement factor to the first angle to determine a second angle between the first segment and the second segment; moving the second link along the second path the second angle to arrive at a predicted location.   
   
   
       10 . A method according to  claim 9 , wherein the first link is a driven link. 
   
   
       11 . A method according to  claim 10 , wherein the first link is on the patient's ramus. 
   
   
       12 . A method of modeling tooth movement, comprising:
 creating a first virtual model of a tooth; creating a second virtual model of the tooth after a period of time;   identifying a rotational axis of the tooth;   projecting an arc along which the tooth will travel centered on the rotational axis.   
   
   
       13 . A method according to  claim 12 , wherein the virtual models are stored on a computer, and wherein the computer performs identifying the rotational axis and projecting the arc. 
   
   
       14 . A method of according to  claim 12 , further comprising:
 making a first positioning location on a patient's mandible;   tracking the movement of the positioning location over the period of time wherein the rotational axis of the tooth is based on positions of the tooth and the positioning location before and after the period of time;   projecting an arc along which the tooth will travel centered on the rotational axis.   
   
   
       15 . A method according to  claim 13 , wherein the virtual models are stored on a computer, and wherein the computer performs the steps of identifying the rotational axis and projecting the arc. 
   
   
       16 .- 17 . (canceled) 
   
   
       18 . A method of modeling tooth movement, comprising:
 creating a virtual model of a patient's mouth;   selecting an element for projecting movement;   determining a first instant center of rotation associated with a first location on the element; determining a second instant center of rotation associated with a second location on the element;   tracing a path of movement through the first location and centered on the first instant center of rotation;   tracing a path of movement through the second location and centered on the second instant center of rotation; and   tracing a path of movement for the element with the first location centered on the first instant center of rotation and the second location centered on the second instant center of rotation.   
   
   
       19 . A method according to  claim 18 , wherein the element defines a link in a virtual four-bar linkage. 
   
   
       20 . A method according to  claim 19 . wherein the pivots in the four-bar linkage are at the first location, the second location, the first instant center of rotation and the second instant center of rotation. 
   
   
       21 . (canceled) 
   
   
       22 . A method according to  claim 18 , wherein the virtual model comprises a three dimensional model.