3D scanners are devices that analyze objects of interest in order to collect data on its shape and appearance so that 3-dimensional, digital models are constructed, useful for a wide variety of applications.In dentistry, the conventional intraoral and panoramic radiography offer two-dimensional view of the oral structures. Because of uperimposition, both technologies have a limited value in detecting subtle anatomical and pathological structures (Hirsch 2007). Digital 3D has increasingly been prominent in dental radiology since the advent of computed tomography. Soft tissue volumetric data and surface topography can be measured accurately, whereas in 2-dimensional radiography, only linear angles, areas and distances can be measured. The ability to capture images in 3 dimensions has opened up new ways for observation and analyses.
Prosthodontics:There are at least 2 methods of usage of the 3D scanner in prosthodontic restorations. One is the use of the scanner in the laboratory and the second is the use of intraoral camera in the dental office. In the first method, the process begins in the dental chair wherein if a crown, for example is needed, the damaged tooth is drilled and a plastic impression from the patient is taken. The impression is then sent to the laboratory where a stone master model and a crown made of wax are created using conventional methods. The 3D process starts with the scanner, where a model of the tooth stump is captured for 3 minutes with an accuracy of 20 micrometers (Geomagic 2004)....
3D Scanner 3
a turntable that tilts, captures then the data from different angles to produce 15 point clouds of
geometric samples of the tooth stump model (Geomagic 2004). The data is then processed in the
control software, which is pre-installed in the computer connected to the scanner. In the Everest
System, the control software has 4 modules: the scan, surface, CAD and CAM modules
(Geomagic 2004). In the scan unit, extremely accurate data of the models is created. In the
surface module, a mathematical surface calculation is automatically performed, detecting
undercuts and preparation lines. After preparation of the model, the file is then passed on to
the CAD module. In the CAD module, the design of the final copings or bridges for example,
happen on the computer screen providing a digital approach to traditional steps in the design
process, as well as speeding the design (SensAble Technologies 2008). The CAM module
calculates the cutting data, taking into account the processing properties specific to the material
being used. The data is then transfered to the CNC system called the Everest Engine
(Geomagic 2004). The system is a computerized grinding and five-axis cutting machine defining
horizontal, vertical, pivot, and rotational travel. With the system, several workpieces are
manufactured at one time. Sintering of materials for ceramic pieces, which takes about 12 hours
is performed using a thermal unit controlled by a microprocessor. The finished piece is then
ready for the patient with a guarantee of perfect fit and with no excess material to be removed.
In the second method, the