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A consideration of how we must do it in order to one day be able to use cad assisted by artificial intelligence.(Part4)


The design of dental prosthetics using CAD called Solidworks

Solidworks has three license styles: Standard, Professional, and Premium. The basic price differs depending on the features. The “General-Purpose CAD” is a better value than the dental-specific CAD, not only in terms of features, but also in terms of price. There are two types of product specifications: the traditional perpetual license type and a license type that can be used only for the duration of the contract. In the perpetual license type, once purchased, the user can continue to use that version of the license forever, although version upgrades are not possible. To upgrade to a newer version, you must sign an annual maintenance contract called a subscription, which is separate from the license. If you purchase a perpetual license, a subscription is only required for the first year.

There are two types of licenses, one for one year and the other for three months, available only for the duration of the contract. Any service pack updates or version upgrades within this contract period are available at no additional charge. Prices for license purchases vary somewhat from agency to agency, and conditions and services also seem to differ.

The reason why we recommend “general-purpose CAD” is because it is a format that supports both surface and solid modeling. It also allows the use of subdivision surface functionality with the addition of third-party options. Subdivision surface functionality means that surfaces or solids can be treated like polygonal modelers, i.e., like clay modeling. This versatility allows you to use a single CAD system for a wide variety of modeling styles and purposes.

Now, with the addition of subdivision surface modeling capabilities that work seamlessly with Solidworks, users can easily create non-geometric shapes and complex surfaces in the original Solidworks product.

Use of dedicated plug-ins

Power Surfacing RE v6 for Solidworks is a plug-in for Solidworks that adds the ability to work with subdivision surfaces in Solidworks. Thanks to this, Solidworks can now be used for dental technology.

Dental technology using general-purpose CAD requires a bit of preparation

The value of using “generic CAD” goes beyond modeling tooth geometry. It allows you to study mandibular motion and also to study occlusion in your own unique way. The trajectories of multiple mandibular movements can be imported into CAD, allowing you the freedom to create devices within CAD to measure and analyze them.

How to fabricate bridges with zirconia frames

We demonstrated the fabrication of a full bridge made of zirconia. Although we do not actually fabricate such long bridges in practice, we created this demonstration video to discuss the fabrication process. It shows the process of creating the cement space and the pontic of the bridge. It also includes the creation of the molar reinforcement.

How to make a single crown with a zirconia frame

The presentation focuses on the creation of frames for the anterior teeth of the mandible.

How to Create Ceramic Crowns

Even though we go to the trouble of using computers to perform dental work, I think it would be boring to simply replace the traditional wax-up operation with computer operation. After all, I think that “crown shape recovery” by artificial intelligence is essential when using computers to perform dental work. Once computers acquire this kind of functionality, I believe that anyone will be able to perform the work easily and without stress. Unfortunately, it is not possible to do so at present.

How to make an inlay

This is a maxillary molar case. Creating the basic surface shape is quite tedious.

Embedding on Zirconia Disk

This operation is used to shave the frame shape.

How to make a metal plate

This is a case of missing right-sided first and second molars

How to make a complete denture (lower jaw only)

The demo will be the lower jaw. Ready-made artificial teeth may not be usable.

Using CATIA and Solidworks:  Setting up simulation motion

It can motion the mandible. The following shows the settings for this.

Masticatory movement simulation

Simulate how crushed food fragments are ejected buccally and lingually when an object is actually chewed instead of the usual lateral movement.

Applications of the Finite Element Method

I don’t know to what extent this is valid, but I applied the finite element method.

Applying Artificial Intelligence to Dental Technology

It has been some time since the use of artificial intelligence, machine learning, and deep learning became a hot topic in the industrial world, and it has already been put to practical use in various fields such as voice synthesis and image restoration. I hear that some of this technology is already being used in dental CAD. I have been advocating the use of “general-purpose CAD” in the dental field, but unfortunately, “general-purpose CAD” with the desired artificial intelligence functionality built in does not yet exist today.

My ultimate goal is to enable dentists to design their own prosthetics using CAD, or to provide direct study of crown geometry in clinical practice. If CAD is too complicated to use, dentists will probably leave it to dental technologists to do it for them. Although we have been trying to port dental technology to “general-purpose CAD” so that anyone can do it easily and accurately, the problem of “generation and editing” of individual crown shapes still remains.

For a single crown or a 3-unit bridge, it is not too burdensome to read a pre-made basic crown shape and manually edit it individually. However, for a full bridge consisting of an upper and lower jaw, it would be very difficult to manually edit each of the 28 teeth individually. It is not possible for a dentist to do this during the day while practicing dentistry. The technology of “automatic crown shape generation with mandibular movement” has been a dream of mine for many years. The main reason for the transfer of dental technology to “general-purpose CAD” was to combine the automatic crown shape generation and shape editing operations.

So how can we achieve automatic crown shape generation? I think we will use artificial intelligence functions, but at this point I don’t know exactly how to do that. In the field of deep learning, examples of using “Python” often appear in many reference books, but most of them seem to be used for 2D image recognition.

PyTorch3D seems to be useful for special libraries that manipulate “point clouds,” such as machine learning for 3D, even when creating 3D shapes, as in this example. However, it is not so widely used at this time, and there are no appropriate manuals available to the general public.

Even Google Trends is unable to collect data on “PyTorch3D” at this level. Although it seems to be rarely searched for today, 3D is an area that will surely become popular in the near future. Google Trend is a tool provided by Google Inc. that allows users to check the trend of searches on Google and shows the number of searches for keywords.

Recently, this kind of book was published. The book “Detailed 3D Point Cloud Processing: Implementing Basic Algorithms in Python – Publisher, KS Science and Engineering Specialty Book, 2022_10_5” has been published. I believe that the day when 3D shape restoration can be realized will come gradually.

Chapter 3 Challenges to Image Understanding