” DOUBLE STEP REVERSE”( DSR): A NEW PROTOCOL IN POLYVINYLSILOXANES( PVS) IMPRESSION- TAKING PROCESS- TWO CASE REPORTS
Figure 19. The crown on 16 after cementation
Figure 20. Clinical picture after the cementation of both crowns
impressions of multiple preparations without worrying about the setting times of PVS when he combines both wash and tray materials. The Double Reverse Step gives enough ease to the operator, allowing him to carefully the preps and apply PVS over multiple teeth in sequence; then doublechecking any potential transudation, and the presence of saliva. Furthermore, the patient’ s increased comfort must be considered, due to the use of less fluid materials that are not likely to leak down the throat if they are in excess, and to the decreased mouth removal time of the tray( 3 minutes).
Figure 21. The crowns from the buccal side
tion and, at the end, was sent to the laboratory. After the laboratory phase, the finishing line of the cases on the respective abutments was checked through an optical microscope and probed carefully through endodontic files from 06 to 150( according to ISO standards) in order to properly assess any hidden gaps( Fig. 13). In the same way, we checked directly in the mouth, with Fit Checker Blue GC before resending the substructures to the laboratory for the ceramic layering. The definitive crown was again controlled and it was clear that there was no more than 120 µ m and a maximum gap of 1 / 10 of the entire extension edge of the crown of 1.6, it was decided to proceed with cementation under dental dam for every single crown( Fig. 14 to 21).
3. Discussion and Results By obtaining the absolute accuracy of the impressions, this new protocol allows the clinician to take
4. Conclusions In our practice, the DSR protocol has become the standard in every clinical situation since it provides us with a perfect control of the operative field, a chance of managing any sudden problems( exudation, crevicular fluid, saliva), a drastic reduction of bubbles on the finishing line( which are often related to the delivery mode of the wash material through the syringe), the absence of the V-shaped voids that often occurs when the delivery of the wash material is delayed or due to an incorrect positioning of the impression tray( not parallel to the occlusal surface nor pushed too quickly). Eventually, we have noticed a greater patient cooperation and a greater serenity during the 3 minutes of the setting time.
Acknowledgments The authors declare no conflict of interest related to this study. There are no conflicts of interest and no financial interests to be disclosed.
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