Inside Dental Technology
Cost-Effective Approaches to Maximizing Esthetics
Finding the right material for a better bottom line
Considering the enormous economic pressure felt by today’s dental laboratories, finding cost-effective strategies for producing highly esthetic restorations has become a priority in keeping the laboratory afloat. For most, developing strategies for controlling manufacturing costs requires a two-phase approach—streamlining processes to reduce labor costs and minimizing the cost per unit relative to the materials selected for the case. The challenge is to accomplish this cost reduction without compromising quality or esthetics. Pressed lithium disilicate (IPS e.max® Press) offers some unique advantages that enable laboratories to balance esthetic demands and economic realities.
Controlling Material Costs
Despite the growing popularity of CAD/CAM technologies, which do offer some benefits in terms of process management, the time-tested process of pressing ceramic materials offers some significant advantages relative to material cost. In the simplest comparison, a single lithium disilicate ingot costing $22.40 shows moderate cost savings over a lithium disilicate milling block costing $31. As we look closer at the cost comparison, however, the milled block is designed to produce one unit only, so the material cost will always be $31 per unit. By comparison, the pressed lithium disilicate was designed to produce multiple units from each ingot. Assuming an average of three units per ingot pressed, the material cost then will be reduced to $7.47 per unit. For laboratories averaging 100 all-ceramic units per week, this represents a potential weekly savings of $2,353.
Of course, this example is based on maximizing the number of units per pressing. One sound strategy for accomplishing this is to batch similarly shaded restorations into a single ring to maximize ingot usage. For example, if today’s production has two restorations requiring an A1 shaded ingot and one restoration requiring A2, it would make economic sense to press all three using the A1 ingot because the A2 shade can be easily achieved with a minor color correction.
Another area where pressed lithium disilicate offers an opportunity for cost savings lies in the streamlined processes available for producing restorations. Two common strategies for creating process efficiencies in the development of wax patterns are rapid prototyping and wax injection techniques.
Rapid prototyping can be highly technological in nature, using CAD/CAM processes to design and print detailed patterns for pressing, or it can be fairly low-tech, using prefabricated wax forms to speed the hand-waxing process. The printing process will produce a more detailed result requiring less hand modification to achieve an anatomically and functionally correct pattern; however, the start-up cost of establishing the CAD/CAM infrastructure can be quite high. This method is therefore best-suited for laboratories with a significant throughput in order to ensure a timely return on investment. For laboratories that do not have the work volume to support the investment in a CAD/CAM system, outsourcing the printed patterns to a milling center may be an option. A low-tech alternative may also be considered in which the laboratory uses pre-manufactured occlusal wax forms to quickly produce the functional areas of the wax-up. Although these forms typically will require hand adjustments to customize the anatomy and occlusal contact relationships, this process requires much less labor than full individual waxing. The axial contours, which normally are less detailed and simpler to form, are then finalized by hand.
Another waxing strategy that can be employed by laboratories creating large reconstructions or smile designs is to use wax injection techniques. Since these types of cases typically involve a detailed diagnostic wax-up to guide the temporization of the prepared teeth, a silicone matrix taken from the wax-up or a model of the approved temporaries can serve as a mold in which to inject wax to form the initial wax-up. This will greatly speed the waxing process, since upon injecting wax into the matrix, there will be only minor corrections necessary to finalize the wax contours. There are commercially available jewelry injectors that can be used for this process; however, a very good result can also be achieved using simply a glass eye dropper, a heated pot of wax, and a Bunsen burner.
A final thought on the process advantages that can be achieved with pressed lithium disilicate lies in its ability in many cases to press to full contour and deliver the restoration through a simple staining technique. With the wide selection of ingot shades and translucencies, it makes sense to, whenever possible, minimize the labor costs associated with layering techniques. While in the esthetic zone some minimal layering may at times be necessary to meet the esthetic demands of the case, a monolithic approach, whenever possible, can not only give exceptional esthetic results, but can also provide the added benefit of placing the occlusal loads on the high-strength and highly durable lithium disilicate material.
In today’s competitive business environment, where cost-effective manufacturing practices are key to the success of the dental laboratory, pressed lithium disilicate offers some unique advantages that can make a significant impact on the business’s bottom line.
About the Author
Jeff Smith, CDT is a technical representative for Ivoclar Vivadent.