Accuracy of a separating foil impression using a novel polyolefin foil compared to a custom tray and a stock tray technique

Abstract

PURPOSETo compare the dimensional accuracy of three impression techniques- a separating foil impression, a custom tray impression, and a stock tray impression.MATERIALS AND METHODSA machined mandibular complete-arch metal model with special modifications served as a master cast. Three different impression techniques (n = 6 in each group) were performed with addition-cured silicon materials: i) putty-wash technique with a prefabricated metal tray (MET) using putty and regular body, ii) single-phase impression with custom tray (CUS) using regular body material, and iii) two-stage technique with stock metal tray (SEP) using putty with a separating foil and regular body material. All impressions were poured with epoxy resin. Six different distances (four intra-abutment and two inter-abutment distances) were gauged on the metal master model and on the casts with a microscope in combination with calibrated measuring software. The differences of the evaluated distances between the reference and the three test groups were calculated and expressed as mean (± SD). Additionally, the 95% confidence intervals were calculated and significant differences between the experimental groups were assumed when confidence intervals did not overlap.RESULTSDimensional changes compared to reference values varied between -74.01 and 32.57 µm (MET), -78.86 and 30.84 (CUS), and between -92.20 and 30.98 (SEP). For the intra-abutment distances, no significant differences among the experimental groups were detected. CUS showed a significantly higher dimensional accuracy for the inter-abutment distances with -0.02 and -0.08 percentage deviation compared to MET and SEP.CONCLUSIONThe separation foil technique is a simple alternative to the custom tray technique for single tooth restorations, while limitations may exist for extended restorations with multiple abutment teeth.

Is a Wiggling-Motion Modified Two-Step Impression Technique as Accurate as Conventional Techniques in Restorative Dentistry?

“…Another measuring method that has been described is via image measuring software. Images were taken through a digital camera [31], or a digital camera attached to a microscope [32,33], and then measurements were taken through calibrated image software. For the present investigation, we used a laboratory scanner to scan all the models, and then STL files were processed through three-dimensional analysis software to produce all the measurements.…”

“…Even though, in some studies, varying undercuts were made at the cervical part of metal dies [26,32], those simplified master models cannot safely simulate clinical conditions. In order to get clinically relevant results, we tried to recreate a common clinical situation by using three metal dies in a partial edentulous arch, similar to two other studies [21,33]. The dies simulated full-crown preparations, two for a FPD and one for a single crown at the opposite site.…”

“…Putty/wash impressions can be conducted using either one-step or two-step techniques. Some authors have suggested that the impression technique does not play a significant role in the accuracy of impressions with addition-type silicone [23,31,33]. On the contrary, there are many studies which suggest that two-step techniques result in more accurate casts than the one-step technique [14,15,19].…”

The aesthetic management of a midline diastema with direct composite using digital smile design, putty index and button shade technique: A case report

“…The putty material in the one-step putty/wash technique also tends to push the wash impression material away from the prepared tooth and from important areas such as the finish line, which can be obscured by the putty material and thus cannot record detail satisfactorily. [22][23][24] The disadvantage of the putty index method is that some of the wash impression material can spread occlusally when the putty impression material is placed back or when the wash material is introduced. This can cause distortion that reduces dimensional accuracy.…”

Final Retention of Recemented Dental Casting Luted with Different Resin Cements

“…In the initial step, separating foils (Plicafol, GS Folienfertigung, Lebach, Germany) were applied on the external tooth surfaces, and the preliminary impression was made by putty material. After the setting time, the foil was detached and then the next phase of impression was made with low-viscosity material and poured with type IV dental stone (GC Fujirock EP, GC Corp, Leuven, Belgium) (16). The wax patterns were prepared with a flat occlusal surface and 0.5 mm thickness using type I blue inlay wax (Kerr/Sybron, Orange, CA, USA).…”