Making impressions of abutments prepared using the subgingival vertical preparation technique in full-mouth rehabilitation cases is challenging, both in terms of bleeding control and effectiveness of gingival displacement. Although gingival retraction techniques include the use of gingival cords and astringents, which represent the current gold standard, they do not guarantee the opening of the gingival sulcus to ensure an uninterrupted reading stream of all the arch elements. In fact, once the retraction cord is removed, the gingival sulcus tends to revert to its original position after the initial 60 s, thereby preventing the detection of the subgingival preparation of most elements in the full arch by the scanner. Thus, to ensure precise recording of the subgingival preparation of all the arch elements, various scanning software techniques, such as cutting and stitching the areas of the distorted impression, have been devised. The prosthetic technique described in this article uses modified provisional restoration in its margins, thereby allowing impression making of individual teeth or the full arch. Upon removal of the provisional restoration, gingival displacement exposes the subpreparation zone, with pink and nonbleeding gingiva, which maintains its stability beyond 5 min. This technique allows immediate recording of the full arch, thereby reducing the scan time in the absence of the use of cords and anesthesia, interference at the apical one-third, interruptions, mesh hole creation, and overlapping seam. Thus, this technique improves overall patient compliance and the chairside time.
Stefano et al. (Thu,) studied this question.