Graphics Technology In The Digital Processing Of Dental Casts

Orthodontics is very important to dentistry. Now the tools used for measuring dental cast which is pivotal for saving the information are rule and brass wires, the result of it is effected by manipulator, precision and efficiency are ecumenic, It is very difficult to keep the dental cast well because it is effected by temperature and humidity easily. The digital processing which is high subtly and simple become more and more important for stomatology. This paper first introduces the method of getting two-dimensional digital images information by the basic principle of optics and processing the digital images by the computer image processing technology, and the two-dimensional means to measure dental cast by comparing it with reference line for getting the valuable medical information. The error of result is analyzed and then we know that the longer the reference line is, the smaller the error is, and discuss its realization by C++ language. And the paper introduces the basic principle of getting the dental cast three-dimensional data, discusses the methods of the construction of surface path, the conversion of coordination, the concept of windows and wiew and the conversion of them, projection transformation and illumination mode which are used in the processing of tree-dimensional image construction, analyses the real dental cast 3-D digital information, shows the flow of displaying the exterior three-dimensional data of dental cast, and the method to save and label the scan datas of dental cast by arrays with flags is bring forward, so we can replace the complex matrix calculation with simple mathematic calculation in the processing of examination, put forward the method that we can get matching points in the condition of influencing the dental cast trivially by deleting the scanning points in the relatively smooth scan beam, that we can get construct quadrangle plane by triangle plane and show it by analyzing its illumination mode, and finally show the result of constructing the fragment of dental cast by this means. To contrast the advantages and disadvantages of 2-D measurement with those of 3-D measurement, and get the result that 2-D measurement cost fewer money, realize easily, but it can process datas only on a plane., and 3-D measurement can process datas in 3-D space, measure the dental cast from different direction, but it need high precision measurement instrument, cost more and the calculation is complex. The paperintroduces the importance of keeping 3-D conformation data by virtual reality, that is it can lessen the difference between real model and constructional model. To realize the keep of dental cast by object mode, and advise to realize the 3-D measurement of dental cast by virtual reality technology. The digital process improve the precision and efficiency greatly, can keep data constantly, and change the conventional method of diagnosis radically for doctors.