Annotation
Formation of the occlusal surface of the restoration is possible in several ways - the Correlation correlation technique, the Replication replication technique, the Data base modeling technique or the Biogeneric biogenerics (for the latest versions of the program) with and without antagonists .
To carry out the correlation technique, it is necessary to preserve the shape of the occlusal surface of the tooth before preparation using the optical impression in the “Occlusion” section.
Further, after preparing the virtual model and drawing the preparation boundaries, the stage of introducing the equator line and the copying line is proposed. The pink equator line proposed by the computer should be corrected and drawn so that it repeats the outer contours of the original tooth, recorded on a preliminary optical impression in the occlusal view. To correct this line, double-clicking on the cursor marks the starting point and then smoothly, with the segments indicated by single clicks on the left key, a new line or fragment is drawn. Ends with a double click on the left key. After editing the equatorial line, go to edit the copy line by pressing the “Next” button. On the new versions of the CEREC program, there is no equatorial line correction stage. The green line of copying on the original tooth limits that part of the occlusal surface, which should be transferred to a new restoration. To improve the quality of copying, it is necessary to expand the copy line as much as possible so that it covers all the outer slopes of the hillocks and approaches the equatorial line (equatorial level).
Imposition and intersection with the equatorial line (equator), as well as expansion on vertical vertical planes, as all this leads to design errors, is unacceptable.
After this, the occlusal surface itself is transferred to the restoration. The system proposes the preparation of the restoration, taking into account the correlation technique. It is possible to control the quality of copying the occlusal surface during the further virtual refinement of the finished restoration. By pressing the “Occlussion” button on the 3D model image, you can turn the overlay of the original occlusion image on and off. Copying and overlaying can be considered correct if, when the “Occlussion” button is turned on, the restoration is evenly covered with gray specks. This restoration completely repeats the shape of the initial occlusal surface. The “Occlussion” button in the “View” window is active only if an optical impression has been made in the occlusion section.
When constructing a restoration from the database, taking into account antagonists, after preparing the model, the stage of trimming the imprint of the antagonist “Trim antagonist” (bite registration) is proposed. On the screen with the help of the cursor and the line it is necessary to select the imprint of the tooth or antagonist teeth corresponding to the area of the occlusal surface of the restoration.
To prevent design errors, one should not unnecessarily extend the boundaries of antagonist trimming, that is, approach the equators and exit to the vertical vertical surfaces of the antagonist tooth. The peculiarity of working with a line in this situation is that a certain zone (in this case, from the antagonist print) is allocated. Therefore, to complete the trimming of the antagonist imprint, the line that started “from outside” must cross (close) to limit the selected zone.
Finish the outline by double-clicking on the left key. Only the selected area remains on the screen. It will be the upper limiter for the virtual modeling of the restoration.
When modeling the restoration with allowance for antagonist teeth, the "Antagonist" button is active in the "View" window. When you click on it in the upper left corner of the screen, the Antagonist function settings menu appears.
The program "Biogenerika", introduced in 2005, allows you to recreate the shape of the chewing surface of the tooth, taking into account the basic laws of gnathology. The system calculates the anatomical shape of the tooth, as close as possible to the individual form of the tooth being restored, reading information from the neighboring teeth, stores it on a virtual model, focusing on the approximate teeth and antagonist teeth.