WO2006016389A1

WO2006016389A1 - Dental scanning method using a lcd projector, a ccd video camera and mirrors

Info

Publication number: WO2006016389A1
Application number: PCT/IT2005/000485
Authority: WO
Inventors: Guido A. Danieli; Gionata Fragomeni; Francesco Giuzio
Original assignee: Calabrian High Tech Srl
Priority date: 2004-08-09
Filing date: 2005-08-08
Publication date: 2006-02-16
Also published as: WO2006016389A9; ITCS20040012A1; EP1898828A1

Abstract

Implantology allows to return a correct masticatory cycle in case of very damaged, if not absent dentures. At the actual technological level, this requires high preparation times, between initial dental embossing determination and prosthesis implant, with an entire series of intermediate steps, each of which requires days and sometimes months. This often causes a possible decay of the implant, that is not loaded for long periods. Purpose of the present invention, a new technology allowing to shorten such times, bringing potentially to a single day the time to realize a dental prosthesis, from embossing detection to implant and prosthesization. The substantial innovation consists in a new method for direct scanning of the denture shape, that allows, using a combination of instruments already available on the market and new software, to immediately realize prosthesis defined with this methodology usin numerical control milling machines.

Description

New Technology for one-step Prosthetic Implantology General Description of the Previous State of the Art.

Implantology is becoming an attractive alternative allowing to return to normal masticatory cycles patients having severely damaged denture if not totally absent. But while up to now it was necessary to distinguish between the phase of implant of the artificial root from the following phase of load, the principle of early loading as a strategy to improve the following rehabilitation is gaining momentum. This is however practically impossible to date, since it is necessary to accomplish a series of tasks, each of which requires a well defined actuation time, often of the order of a few days. This without taking into account the fact that dental embossing detection is one of the operations least accepted by the patient, even if unavoidable to build a correct prosthesis.

Till today, in the more advanced technologies of embossing detection, this, once obtained, must be scanned to import in CAD the necessary information to the preparation of the correct prosthesis. Which often requires sending the embossing in specialized centres lengthening the times. Purpose of the present patent is the description of a new technology allowing to shorten these time delays, bringing potentially to one day only the actuation time of a dental prosthesis. Substantial process innovation, a new method for direct scanning the patient's denture. Description of the preferred embodiment The method to be used for scanning is structured light, simple, economic and precise method of shape detection, presently utilized mainly in detection of the anatomically correct shoes, and for posture measurements. The method is based on the fact that projecting a series of horizontal lines on a surface with a certain angle with respect to the perpendicular to said surface, while detecting the lines from a different point of view, the lines are seen as deformed when the surface is not oerfectlv flat and oeroendicular to a olane containing both the central beam of the projected light and that of the receiving beam. In fact this curvature allows, through calibration, to correlate the displacement from the horizontal and the local depth of the point observed. Projecting also, or in sequence, lines inclined by 45°, it is possible to correlate also the relative depth between horizontal lines. Projecting then in rapid sequence various lines of different thickness and position both horizontal and inclined, it is possible to obtain the shape with a high precision. This is simple when surfaces are relatively smooth, but becomes extremely difficult and complex in the case of denture shape detection, both for the small access size and the complexity of the surfaces. However we believe we will be able to succeed using a series of small mirrors fixed to a rigid structure to be inserted into the mouth, also fixed to both image projector and detector, as usually done to take pictures of the teeth.

Projecting then the images by sectors, while the rest of the field is darkened, one should be able to scan the entire cavity in extremely reduced times, eventually using more digital cameras in order to obtain more high resolution images in reduced sampling times, or a single video camera of very high resolution. A following post processing could allow, in a few minutes, to obtain 3D images of the oral cavity, that could be superimposed to previously obtained CAT representation of the mouth, in order to better study also the bone situation, not evidenced by an external scanning process. Once obtained the 3D image of the oral cavity the doctor may decide which are the best positions for the implants in order to obtain the desired results. He will then proceed with the surgery implanting the new artificial roots. Once this is done, special identifying abutments will be placed on the implants, then the digital acquisition will be repeated, new data will be supplied to the CAD program that will propose to the doctor a possible solution for the prosthesis. Finally the numerical control milling machine will produce the prosthesis to be immediatelv installed in the ϋatient's oral cavitv if the NC milline machine is near bv. If this were not the case, this operation will take place in the following days, but early prosthesis loading and high precision will be obtained in any case.

Figure 1 shows projector and video camera fixed together and to the mirror that, introduced into the patient's mouth, allows the embossing detection.

Claims

Claims:

1) New Technology for one-step Prosthetic Implantology consisting in a new equipment for the detection of the dental model on line utilizing a structured light scanner.

2) In particular, the structured light scanner referred in claim 1 will consist in a LCD projector and a CCD video camera both high definition, mutually placed in a position defined a priori, and by a system of mirrors fixed to a small frame, itself fixed to projector and video camera, to be placed in the patient mouth, and that, illumined by sectors and sequentially, allow the video camera to acquire the images needed to shape reconstruction.