Method for teeth model parameterization

Abstract

The invention discloses a method for teeth model parameterization. The method comprises the steps of calculating geometric center points of all teeth; fitting an upper jaw dentofacial plane and a lower jaw dentofacial plane, and calculating an upper jaw dental arch curve and a lower jaw dental arch curve; determining tip points of canine teeth of the upper jaw and the lower jaw; determining far-near-middle points, near-middle points and far-middle points of the teeth; determining a teeth coordinate system according to the tip points, the far-near-middle points, the near-middle points and the far-middle points; calculating FA points, central points and cutting edge points of the teeth, and the near-far-middle cheek points of accessional teeth; performing lip cheek-direction adjustment, tongue jaw-direction adjustment, single-tooth characteristic point adjustment and original tooth die long-axis adjustment; arranging the teeth at a single jaw according to a tooth position number sequencefrom incisor teeth along a dental arch through using the middle line of the dental arch as a reference; calculating a collision value between the single tooth and the adjacent tooth with a relativelysmall tooth position number, and moving a near-middle edge point according to the collision value. The method of the invention effectively improves accuracy and rationality of the parameters after teeth model parameterization.

Description

technical field [0001] The invention relates to a tooth model parameterization method. Background technique [0002] Tooth model parameterization refers to the abstraction of the tooth model into a combination of a three-dimensional space coordinate system and several feature points, so as to be used for the calculation and description of the position and posture in space. By 3D scanning the patient's bite mold, the digital three-dimensional model of the patient's teeth can be obtained, and then the individual digital model of each tooth can be obtained through the operation of recognition and segmentation. Using the tooth model parameterization method, the three-dimensional space coordinates of the tooth model can be obtained system and feature points. [0003] There are two main defects in the tooth model parameterization technology that has been widely used at present: [0004] 1) High dependence on the integrity of the patient's teeth. [0005] a) The existing tooth m...

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Problems solved by technology

[0005] a) The existing tooth model parameterization technology is based on the morphological characteristics of the tooth model itself, and the three-dimensional space coordinate system of the tooth model is obtained by marking the feature points and calculating the feature points. However, in actual cases, the patient's teeth are often Defects, abrasions, etc., make the patient's tooth model unable to accurately reflect its morphological characteristics

[0006] b) In the pre-order steps of the digital processing of the tooth model, the identification and segmentation operations may cause the tooth model to be incomplete, or the gums will swell when the patient bites the mold, which will also cause errors and omissions in the identification and segmentation, resulting in the obtained tooth model deviates when parametrized

[0007] 2) Only the shape of the tooth itself is considered and the relationship between adjacent teeth is ignored

[0008] a) Existing methods will perform parameterization based on the morphological characteristics of a single tooth, but the so-called concept of tooth alignment is originally an evaluation of the arrangement of multiple teeth, so only the parameterization of a single tooth is considered. In the process of arranging teeth, it is often impossible to provide the reference function of parameters for arranging teeth

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