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    Inside Dental Technology

    October 2012, Volume 3, Issue 9
    Published by AEGIS Communications


    Articulating Your Way

    The versatile MainStay™ Disposable Articulator offers many advantages.

    By Bernie Jaroslow, CDT

    From fully functional and adjustable versions to the plastic simple hinge variety, dental articulators have offered features to satisfy the articulation needs of any dentist and dental laboratory. While most articulators are designed to replicate the hinge movements of the mandible, they differ greatly in their cost, adjustability, and function. The latest iteration, plastic disposable hinges, were designed to save time, money, and waste. Some use dowel pins and require multiple gypsum pours and set times, while others may offer a single gypsum application.

    The newest addition to the disposable articulator group gives the laboratory a choice. The laboratory can choose between single-pour pin or pin-less models—or combine the two styles in the upper and lower arches. In addition, Whip Mix’s MainStay™ Disposable Articulator does not require model formers or a gypsum base—which saves time/money—and it adjusts to accommodate any occlusal relationship.

    Its unique base was designed without walls or raised edges that would normally interfere with seating the dies and model segments. This unique feature also means that it can easily be used with gypsums of all expansion ratios. The base also has a spine built into it to prevent lateral swivel movement of the dies once they are placed into position. The raised numbered areas also make replacing the segments fast and simple.

    Any articulator must be designed to achieve vertical closure at the proper height. The MainStay Articulator offers two ways to do that. Built-in posterior vertical stops provide the necessary inter-arch distance to keep the vertical measurement where it needs to be. To further reinforce that terminating position, the system provides the user with rods that, when glued in place, ensure a definitive and consistent custom vertical stop. This is particularly useful for edentulous or partially edentulous arches.

    The MainStay Articulator is available to use without pins in the quadrant design, but the articulator is available with special dowel pins for full-arch, anterior, and quadrant trays. Unlike conventional dowel pins, which rotate freely once they are lifted even a fraction of a millimeter, the incomparable MainStay pins feature two flat sides and a very long, gradual taper that prevents the pin from rotating within the articulator base. The step-by-step technique for the pin and pinless Mainstay articulator is very simple and starts with preparation.

    Preparation

    As with any technique, first and foremost, preparation is required. Place the articulator hinge sections back to back on the bench and snap them together (Figure 1). Trim the impression to ensure it fits between the trays.

    Main Model

    To position MainStay pins (pin articulator only), place the preparation side of the impression above the base, and mark the center of the prepared tooth area. Place the pins in each section of the working base that you wish to remove (Figure 2). Be sure the center of the prepared tooth is aligned with the base. Tip: A separating medium may be used to ensure easy separation of the model from the articulator.

    Starting with the working side, pour the die stone into the impression and base (Figure 3).

    After pouring the impression, wait until the stone has a sufficient body before placing the impression accurately on the base.

    Opposing Model

    Invert the articulator and pour the opposing base and impression (Figure 4). Tip: When the stone has set slightly, remove the excess with your finger or a spatula.

    Finishing

    When the stone is set, separate the model from the impression, then use an arbor band to trim the sides. Trim and section the models on the base and remove the dies (Figure 5). Return the model sections to the base for the first 24 hours as the stone continues to expand and set. Tip: If the occlusion is not right, heat above or below the hinge area to soften the articulator and properly align the occlusion (Figure 6). Cool the hinge area to fix the position. Tip: If the occlusion is open, break off the built-in support rods from both sides (Figure 7).

    The auxiliary support rods are also available to create a stable and positive vertical stop. Place the rod into the radius cutout in the back of the articulator (Figure 8), and place the other end onto the flat portion of the opposing half (Figure 9). Cut the appropriate length, and use the MainStay glue to fasten the rod into place. Tip: The pin quadrant and pin-less quadrant articulator halves may be used together (Figure 10).

    Bernie Jaroslow, CDT, is the lab product manager for Whip Mix Corporation in Louisville, Kentucky.

    Disclaimer

    The preceding material was provided by the manufacturer. The statements and opinions contained therein are solely those of the manufacturer and not of the editors, publisher, or the Editorial Board of Inside Dental Technology.

    For more information, contact:

    Whip Mix Corporation
    Phone: 800-626-5651
    Web: www.whipmix.com


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    Image Gallery

    Figure 10 The pin quadrant and pin-less quadrant articulator halves may be used together.

    Figure 10

    Figure 1 Place the articulator hinge sections back to back on the bench and snap them together.

    Figure 1

    Figure 5 Trim and section the models on the base and remove the dies.

    Figure 5

    Figure 2 Place the pins in each section of the working base that you wish to remove.

    Figure 2

    Figure 3 Pour the die stone into the impression and base.

    Figure 3

    Figure 4 Invert the articulator and pour the opposing base and impression.

    Figure 4

    Figure 6 If the occlusion is not right, heat above or below the hinge area to soften the articulator and properly align the occlusion.

    Figure 6

    Figure 7 If the occlusion is open, break off the built-in support rods from both sides.

    Figure 7

    Figure 8 Place the rod into the radius cutout in the back of the articulator.

    Figure 8

    Figure 9 Place the other end of the rod onto the flat portion of the opposing half.

    Figure 9