KR20220120761A - Tip structure and method for compensating the cumulative tolerance of the oral scanner - Google Patents

Abstract

The present invention relates to a tip structure for compensating for a 3D cumulative tolerance of an oral scanner, which mounts two or more mirrors to measure the exact distance between upper and lower or left and right teeth, and when an image is acquired by an oral scanner, reflects the measured exact distance between the teeth to compensate for a cumulative tolerance of the oral scanner; and a method thereof. The tip structure includes: a light output unit for outputting a predetermined light source; two or more mirrors mounted on the tip and reflecting the output light to left and right or upper and lower teeth; and two or more cameras disposed on the left and right sides of the light output unit to take images of teeth reflected from the mirrors.

Description

Tip structure and method for compensating the cumulative tolerance of the oral scanner

The present invention relates to a tip structure and a method for compensating for a 3D cumulative tolerance of an intraoral scanner, and more particularly, two or more mirrors are mounted to measure the exact distance between upper and lower or left and right teeth, and when acquiring an image with an intraoral scanner It relates to a tip structure and a method for compensating the 3D cumulative tolerance of the oral scanner that compensates the cumulative tolerance by reflecting the measured accurate inter-tooth distance.

Currently, as a method of manufacturing a dental prosthesis such as an inlay, a crown, or a bridge, a method of manufacturing a metal material or a ceramic material by casting a lost wax process is employed.

However, in recent years, as a method of manufacturing a dental prosthesis instead of the lost wax method, after measuring the oral cavity of teeth and gums using an optical three-dimensional camera, a CAD/CAM system is used to design and manufacture a dental prosthesis. The system is attracting attention. A representative example of this system is the Cerec system.

The CEREC system performs intraoral measurement of teeth and gums by directly reading the shape of teeth in the oral cavity using an optical three-dimensional camera.

As the optical three-dimensional camera, a camera that performs non-contact three-dimensional measurement typified by a phase shift method or a spatial coding method is used. In this way, by using an optical 3D camera and a CAD/CAM system as a conventional method of manufacturing a dental prosthesis, it is possible to manufacture a dental prosthesis more efficiently than the lost wax method, and at the same time, it is possible to improve the accuracy of fit in the oral cavity. Excellent dental prosthesis can be manufactured.

However, in the case of the conventional oral scanner, there is a disadvantage in that the tolerance that occurs in the process of measuring 1 to 2 teeth and stitching (Stitching) to image in 3D increases.

An object of the present invention is to provide a distance measuring device for accurately measuring the distance between teeth to reduce the cumulative tolerance that may occur during the oral scanner process.

In addition, an object of the present invention is to provide a method of compensating for cumulative tolerance for reducing cumulative tolerance that may occur during an oral scanner process by using the measured exact distance between teeth.

In order to achieve the above object, the present invention relates to a tip structure for compensating for a cumulative tolerance in an intraoral scanner, a light output unit for outputting the predetermined light source, is mounted on the tip and transmits the output light to left and right or upper and lower teeth It may include two or more mirrors for reflecting the light, and two or more cameras disposed on the left and right sides of the light output unit to photograph the teeth reflected from the mirror.

Also, the optical output unit may be a DLP.

Also, the camera may be a stereo vision camera.

In addition, the distance measurement may use the structured light distance measurement principle of the optical triangulation method.

On the other hand, the present invention is a light output unit for outputting a predetermined light source, two or more mirrors mounted on the tip to reflect the output light to left and right or upper and lower teeth, teeth disposed on the left and right of the light output unit and reflected from the mirror It relates to a method of compensating for the cumulative tolerance of an oral scanner using a device for measuring distance between teeth including two or more cameras that photograph It may include measuring the distance between the teeth and compensating for the accumulated tolerance.

In addition, in the step of measuring the distance between teeth, if left and right between teeth can be measured, the left and right tooth distance is measured to compensate for the accumulated tolerance, and when it is not possible to measure the left and right between teeth, the upper and lower tooth distance is measured to provide location information may be compensated for the occlusal data of the first scan data.

In addition, in the cumulative tolerance compensation step, (B - A) / (N - 1) values (A: cumulative tolerance value generated while moving from tooth 1 to tooth N, B: measured number 1 and distance between teeth N) can be added or subtracted.

The present invention can measure two or more teeth at the same time by using two or more mirrors at the tip of an oral scanner, to know the exact distance between the teeth, and to image an accurate 3D image by compensating for the accumulated tolerance.

1 is a conceptual diagram showing a tip structure for compensating for a 3D cumulative tolerance of an intraoral scanner according to an embodiment of the present invention;
2 is a flowchart illustrating a method for compensating for a cumulative tolerance according to an embodiment of the present invention.

Advantages and features of the present invention, and methods for achieving them, will be explained through the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. However, these embodiments are provided to explain in detail enough to be able to easily implement the technical idea of the present invention to those of ordinary skill in the art to which the present invention pertains.

In the drawings, embodiments of the present invention are not limited to the specific form shown and are exaggerated for clarity. In addition, parts denoted by like reference numerals throughout the specification denote like elements.

In the present specification, the expression “and/or” is used to mean including at least one of the elements listed before and after. The singular also includes the plural, unless the phrase specifically dictates otherwise. Also, as used herein, a component, step, operation, and element referred to as “comprises” or “comprising” refers to the presence or addition of one or more other components, steps, operations, elements, and devices.

Hereinafter, a preferred embodiment according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a conceptual diagram illustrating a tip structure for compensating for a 3D cumulative tolerance of an intraoral scanner according to an embodiment of the present invention.

Referring to Figure 1, the present invention is largely composed of a body portion and a probe tip. A light source and a camera module facing forward are mounted inside the main body, and the probe tip is formed such that its rear end is coupled to the front of the main body and its front end is inserted into the oral cavity of the examinee.

A scan hole that is opened toward a subject's teeth is formed at the front end of the probe tip, and a mirror is inclinedly disposed inside the scan hole.

The mirror reflects the light emitted from the above-described light source and sends it out through the scan hole, and reflects the light reflected back to the teeth toward the main body in which the camera module is located.

In particular, the probe tip structure in the embodiment of the present invention may be configured to include two or more mirrors inside the scan hole at the front end of the probe tip in order to accurately measure the distance between teeth. This is to check the distance between the left and right or upper and lower teeth at a time by the two or more mirrors.

Hereinafter, a method of measuring the distance between teeth using two mirrors will be described in an embodiment of the present invention.

The distance between the teeth can be measured using the optical distance measurement principle of the optical triangulation method. That is, cameras are installed on the left and right around the light source to measure the structural light reflected from the two mirrors to measure the distance between the teeth.

The light triangulation method measures the distance between the projected light and the reflected light as each light source is reflected from the surface and returned to the image sensor, and the distance of the object is measured based on the relative position and angle between the light source and the sensor. to be.

Specifically, the light source may be a digital light processing (DLP) projector pattern, and since the pattern has unique distance information according to the pattern position, the distance may be measured using the pattern position. In addition, the left and right cameras with respect to the light source may be stereo vision type cameras.

In another embodiment, the confocal laser scanning method uses a laser as a light source, and among the light reflected from the tooth surface and coming to the lens, only the light matching the focus through a pinhole such as a small needle hole is received by a photodetector and digitized to form an image way to do it

In another embodiment, the active wavefront extraction technique is a method of generating a three-dimensional image by successive camera imaging using a rotating lens stop instead of using a laser to obtain surface shape data.

2 is a flowchart illustrating a method for compensating for a cumulative tolerance according to an embodiment of the present invention. Referring to FIG. 2 , first, the entire oral cavity is scanned in 2D or 3D while moving from the first to the Nth tooth. At this time, a tolerance occurs between the first scanned tooth (first tooth) and the last scanned tooth (Nth tooth). That is, a tolerance occurs when 3D scan data is stitched in the scanning process of the intraoral scanner.

Next, the exact distance between teeth is measured in order to reduce the generated tolerance.

The exact distance between the teeth can be measured using the tip of the oral scanner equipped with the two mirrors described above. Preferably, the tip of the scanner scanned for the first time is replaced with a tip having two mirrors to measure the exact distance between teeth in an optical triangulation method.

Here, when the left and right teeth can be measured, that is, when the tip of the scanner can measure the left and right intervals between the upper and lower jaws, the left and right teeth are scanned and the distance value between the left and right teeth is compensated for the primary scan data. do.

If it is not easy to measure the left and right distance of a tooth due to the gum, tongue, or oral structure in the mouth, for example, if the left and right measurement is impossible due to the oral structure of the tip of the scanner, the opposite tooth, that is, the upper and lower teeth Measure the distance value between the liver (mandibular and maxilla). In this case, the occlusion information of the first scan data is acquired by scanning the upper and lower teeth data, and the accumulated tolerance is compensated by calculating the distance between the upper and lower teeth using the occlusion information.

The cumulative tolerance compensation value may use the following equation.

Add or subtract the value of (B - A) / (N - 1) at the distance of the teeth next to each other

(A: Cumulative tolerance value generated while moving to teeth 1 to N, B: distance between measured teeth 1 and N)

Accordingly, the accumulated tolerance compensation value can be obtained by adding or subtracting the value derived from the above equation.

For example, in the first scan, the cumulative tolerance value measured between teeth 1 and 5 is 10, and when the distance between teeth is measured with a tip equipped with two mirrors, the distance between teeth 1 and 5 is Assuming 5, (5 - 10) / (5 - 1) = -5 / 4.

Therefore, by adding or subtracting -5/4 from the neighboring tooth distance, a distance value in which the accumulated tolerance is compensated can be obtained.

Although the present invention has been shown and described in relation to specific embodiments in the above description, it is common knowledge in the art that various modifications and changes can be made without departing from the spirit and scope of the invention as defined by the claims. Anyone who has it will know it easily.

Claims (7)

It relates to a tip structure for compensating for a cumulative tolerance in an intraoral scanner,
a light output unit for outputting the predetermined light source;
two or more mirrors mounted on the tip to reflect the output light to left and right or upper and lower teeth;
Device for accurate distance measurement between teeth including two or more cameras disposed on the left and right of the light output unit to photograph the teeth reflected from the mirror. According to claim 1,
The device for accurate distance measurement between teeth, characterized in that the light output unit DLP (Digital Light Processing). According to claim 1,
The camera is a device for accurate distance measurement between teeth, characterized in that the stereo vision camera. According to claim 1,
The distance measurement is
A device for accurate distance measurement between teeth, characterized in that it uses the optical triangulation-type structured light distance measurement principle. A light output unit for outputting a predetermined light source, two or more mirrors mounted on the tip to reflect the output light to left and right or upper and lower teeth, two placed on the left and right of the light output unit to photograph the teeth reflected from the mirror It relates to a method of compensating for the cumulative tolerance of an oral scanner using a device for measuring distance between teeth including the above camera,
Acquiring primary intraoral dental scan data;
measuring a distance between teeth using the distance measuring device; and
Compensating the cumulative tolerance of the oral scanner comprising the step of compensating for the cumulative tolerance. 6. The method of claim 5,
The step of measuring the distance between the teeth,
If it is possible to measure the left and right between teeth, measure the distance between the left and right teeth to compensate for the accumulated tolerance,
When it is not possible to measure the left and right between the teeth, the method of compensating for the cumulative tolerance of the oral scanner, characterized in that by measuring the distance between the upper and lower teeth and compensating the position information to the occlusal data of the primary intraoral dental scan data. 6. The method of claim 5,
The cumulative tolerance compensation step is
The value of (B - A) / (N - 1) at the distance of the teeth next to each other
A method of compensating for the cumulative tolerance of the oral scanner, characterized by adding or subtracting (A: the cumulative tolerance value generated while moving to the 1st to Nth teeth, B: the measured distance between the 1st and Nth teeth).

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