Options for Aligning 3D Face Models with Dental Jaw Models
The integration of 3D face models with upper and lower jaw models to create a digital virtual patient has become a powerful tool for patient motivation and face-based design for dental planning. One of the challenges in creating this virtual patient is that the face model and jaw models are independently captured by two different types of 3D scanners that have no correlation to each other.
Establishing a correct spatial relationship between the two models is a process of model alignment. Within the Bellus3D dental apps the face and jaw model alignment is accomplished by the repositioning of the face model in 3D space relative to the selected jaw models. This is important to note because the user interface of our apps show alignment adjustments as movements of jaw models which we implemented to make for a simpler user interface within the app. It is also important to note that the spatial alignment relationship that is established between the face model and the selected jaw models is only valid for those models. If the face model is to be used with another set of jaw models a new alignment will need to be established.
General Recommendations and Overview
There are three options for aligning a Bellus3D face model with jaw models that are presented in this document.
1. Dental Pro for iOS
The Dental Pro for iOS app can be used to capture and view a 3D face model and align the face model to a set of imported jaw models. The jaw models can originate from any intraoral or dental lab scanner and must be in either an .stl or .ply file format. Dental Pro uses the concept of a Workspace to contain the 3D face model, jaw models and smile design guides. The models used in the Workspace are selected in the Workspace Creation screen as shown below.
Jaw Models and Face Model selected for a new workspace
To integrate the 3D face model with the 3D jaw model, an opening needs to be cut out of the 3D face model shell to reveal jaw models. This opening is called a lip line cut out.
Once a satisfactory adjustment has been made between the face and jaw models, the resulting aligned face model can be exported from the Tools tab by tapping on the down arrow export icon. Aligned face models can be exported as a .obj, .ply or .stl file for subsequent use in dental planning software.
2. Dental Pro Web
Dental Pro Web is a web-based application that enables viewing, exporting and alignment of 3D face models to jaw models within a web browser. Dental Pro Web is not a scanning app. Some dental practitioners prefer to delegate the alignment of face models with jaw models to the lab or prefer to operate the adjustment work on a computer. The face models shown in the gallery screen of the app are models originating from the user's own Dental Pro iOS account or models the user has upload from using a Bellus3D ARC Camera App. Face models in the gallery can also be models that have been shared by other Dental Pro accounts.
3. ARC Models with Dental Bite Plate
The Bellus3D ARC4 and ARC7 cameras enable the use of the Bellus3D Dental Bite plate enhancement feature. The .stl file of the bite plate can be downloaded from with the ARC scanning app and printed on a 3D printer. The bite plate needs to be attached to a bite fork for placement in the mouth. During normal scanning the ARC scanning software performs smoothing and maps any external objects such as eyeglasses or bite plates as part of the face.
Edges of Bite Plate shown as a result of automatic applied smoothing
By selecting the “Enable Dental bite plate feature” in the ARC 4 or ARC7 scanning settings of the Bellus3D ARC Scan App (see screen below) , the app will detect the presence of the Bellus3D bite plate in the face model and substitute the smoothed bite plate front surface in the model with a sharp well-defined surface to provide more precise points for 3 - point alignment in dental planning software.
Dental Bite Plate Setting Dialog from the Bellus3D ARC Scan App Settings Menu