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18 I I case report _ smile design First, the instant silicone model was lubricated with a water-based lubricant (such as KY Jelly). Next, the putty matrix was filled with bis-acryl and then placed onto the silicone model. After a minute and a half, the provisional was set up and ready to be trimmed. Because this method of temporisation in- volves a quick way to make a model of the prepared teeth, the provisional can be trimmed and polished inthelaboratory.Finishingprovisionalsinthismanner is much more accurate, as well as kinder to and easier for the patient, and particularly the gingival and the preparedandimpressedteeth(Figs.9a–10c). Inordertopreparethegingivaforthefinalimpres- sions, Expasyl (Kerr) was placed around the gum line. Final impressions with a PVS material (examples are Take 1 Advanced, Kerr; and Virtual, Ivoclar Vivadent) were then taken in custom trays. A slow-setting material was used to record her bite registration (SuperDent). In order to cement the provisionals, the same bis-acryl was placed in the temporaries and seated in the mouth. The excess was removed with amicrobrushbeforethematerialset.Thepatientloved the way her provisionals looked and fitted (Fig. 11). There were no surprises, as she had chosen the smile designshelikedbestbeforeanyworkhadevenbegun. When she returned for the final porcelain restora- tions, the patient was concerned that they might not lookasgoodasherprovisionals.Becausetheminimal preparation was all in enamel, we could try the resto- rations with no anaesthetic and no discomfort. This is important to allow the patient to gain a true feel of the teeth, especially when length is being increased. We assured her that we would try-in the restorations and gain her approval before seating them perma- nently.Thus,weinvitedherentirefamilytotheseating appointment in order to offer their opinions. As is often the case, it was especially important to please one family member in particular, and for this case it washerdaughter. For the try-in, we used different shade combina- tions of try-in pastes in order to determine what looked the most natural. I call this the mix-to-match method. This method is especially important for ex- tensive cases with multiple types of restorations and porcelains. In this case, feldspathic porcelain was Fig. 8_Upper preparations and preparation shade. Figs. 9a–10c_Upper and lower indirect provisionals on instant silicone models. CAD/CAM 1_2010 Fig. 8 Fig. 9a Fig. 9b Fig. 10a Fig. 10b Fig. 10c