The use of digital dentistry is increasing at an exponential rate. The digital workflow now includes pre-operative assessment; both digital impressions and CAD/CAM technical stages, any of which may be used by the general dental practitioner to improve the process.
Digital impression taking is by no means a new concept, with a number of prominent systems already demonstrating excellent results. The accuracy of these systems is easily comparable to conventional impressions, but with the digital solutions come many advantages. Dentists can significantly improve their patient’s comfort and satisfaction; digital dentistry will help to streamline their patient’s journey in a way that will reduce unnecessary worry in the chair. Failsafe laboratory communications and cross infection control will reduce waiting times and should increase the overall effectiveness of work completed. With regards to the dental technician, the models may either be milled or printed, and the substructure more readily incorporated into the CAD/CAM systems. The digital files can easily be stored for medicolegal purposes, as well as in case of an emergency.
There has been some discussion as to the perceived disadvantages associated with digital impressions, which can include a learning curve, a diminished speed of impression taking, the need for surface powder and the size of impression units. The CS 3500 digital imaging system from Carestream Dental, has been designed to combat previous weaknesses in other systems.
Firstly, the digital information is collected via a handheld scanner that is not attached to its own specific unit, but rather to any laptop or desktop computer available via a USB connection. This gives the scanner true portability and allows for a greater flexibility of use, especially if surgeries are on different levels.
The CS 3500 is an optical scanner that takes a series of scans of the teeth and soft tissues, requiring no surface powder and thus removing potential difficulties. When a powder is used it is difficult to rescan an area, if, for example, the powder is altered by a misbehaving tongue. But if no powder is required, any areas that necessitate further examination can simply be dried and scanned.
This article aims to document three cases seen in general dental practice in order to demonstrate the effectiveness and benefits of digital dentistry. Cases 1 (figs 1-5) and 2 (figs 6-10) depict single crown examples; case 3 (fig 11-14) demonstrates a case of an anterior three-unit bridge and single crown.
Case 1: Single crown – conventional techniques
The tooth is prepared and gingival retraction cord used in conventional techniques. The teeth and opposing arch are
individually scanned. The teeth are brought into ICP and the occlusion scanned; the margins of the images are then marked by the dentist and emailed to the lab (fig 2). The STL file is imported to a model production software programme (fig 3). The model is then milled, the substructure of the crown milled via CAD/CAM and the final crown veneered with porcelain (fig 4). The crown is then cemented using a glass ionomer cement (fig 5).
Case 2: Single crown – digital techniques
The technical stages differ in this case as the entire crown is manufactured digitally without models. Clinical stages remain the same as for case 1. The tooth is once again prepared and retraction cord used (figs 6 and 7). The STL file is used to digitally design the crown (fig 8). The full contour crown is milled, stained and glazed by the technical team (fig 9) and the crown is then fitted with no adjustments required (fig 10).
Case 3: Anterior three-unit bridge and single crown
Standard techniques are used and the margins of all the preparations are individually marked by the clinician (fig 11). The STL file is used to produce a printed model (fig 12) and to design the zirconia substructure (fig 13). The zirconia substructures are married to the models and the restorations are then veneered. The restorations are fitted using conventional cements (fig 14).
In conclusion, the use of digital dentistry in any of its forms will soon become the norm for general dental practitioners.
References available on request.