Making Accurate Detailed Impressions
A trifecta for impression material with NoCord VPS
Frank J. Milnar, DDS, AAACD
Taking impressions for the dentist is a critical step to create quality restorations. All these steps take time. Pressure, astringency, and time are the elements needed to create the proper environment for taking a good impression. There are well over 40+ brands of impression material offered by nearly 30 different companies.1 It can be overwhelming and confusing to understand and select the right material types and properties for your clinical use.2 NoCord VPS Impressioning System (Centrix, www.CentrixNoCordVPS.com) is one of the newest impression materials in the market today that brings all three critical areas into play. It is an impressioning system that retracts the tissue, stops bleeding, and takes an accurate impression all in one step. It is able to do this because it incorporates the astringent within the NoCord Wash Material (Centrix) and combines it with NoCord™ MegaBody™ Tray Material (Centrix) to help create the force for retraction and hemostasis. The purpose of this article is to introduce a new class of impression material that takes advantage of these properties.
Here is a typical case that one may run into during an average day in the dental office.
A 34-year-old patient presented with decay and discoloration with ferrous contamination under an all ceramic e.max crown (Ivoclar Vivadent, www.ivoclarvivadent.com) on No. 14 (Figure 1). The patient was given a local anesthetic using Anutra’s buffered anesthetic system (http://anutramedical.com). Before removing the crown, an Access Blue (Centrix) quick set impression was made in order to make a temporary restoration. The crown was removed by sectioning it in half using an 850-814-ML diamond (Diatech, www.diatechusa.com). After the sectioned crown was removed, the tooth was re-prepared by removing the decay and stain using an 850-814-ML diamond and H32.31.012 diamond (Brasseler USA, www.brasselerusa.com). The defects in the tooth were filled with the core paste and were finally finished with a final modified chamfer using 850-814.10ML (Diatech).
As a result of extensive subgingival decay on the distal, there was excessive bleeding (Figure 2). NoCord VPS was indicated as our final impression. NoCord Wash Material can be used by itself where there is minimal bleeding because of its astringent property by simply washing and drying the preparation before using NoCord VPS to achieve an accurate impression with gingival retraction. In instances such as this, it may be necessary to control excessive bleeding by using additional hemostatic methods such as GingiTrac (Centrix) (Figure 3).
After the excessive bleeding had mostly been controlled, the impression was taken using NoCord VPS (Figure 4 through Figure 9). Before and after the impression, the preparation was disinfected with Consepsis® (Ultradent, www.ultradent.com). The preparation may be desensitized using Glu/Sense™ Dentin Desensitizer (Centrix), a glutaraldehyde gel in a syringe with a unique sponge tip.
The impression was sent to the laboratory to fabricate the final EZR Zirconia Crown (Valley Dental Arts, http://valleydentalarts.com). The pre-restorative impression was fabricated using Access Blue and the impression taken at the start was used to make the temporary crown using Access Crown Ultra (Centrix). The provisional crown was cemented with Bifix Temporary dual cure (Voco, www.voco.com).
After crown fabrication, the temporary crown and residual cement was removed. The tooth was rinsed with Concepsis, and the fit and occlusion of the crown were verified. The crown was cemented with AbsoLute (Centrix) dual-cure permanent cement (Figure 10 and Figure 11).
The challenge facing dentists every day is to take quality impressions, which requires a trifecta of circumstances—sulcus expansion, hemostasis, and impression accuracy. Approximately 95% of impressions sent to dental laboratories are VPS and more than 80% of cases are single unit. NoCord VPS is the next generation of impression materials that allows the dentist to save time with fewer steps and excellent results.
1. Cowie RR. Understanding impression materials and techniques. Dent Today. 2007;26(3):108, 110-111.
2. Brown RL. An elastomeric impression material breakthrough. Dent Today. 2009;28(10):118, 120.
3. Boksman L. Eliminating variables in impression taking. Ont Dent. 2005:34:22-25.