Surgery Setup in the Surgery-First Approach

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© Springer Nature Singapore Pte Ltd. 2021

J.-W. Choi, J. Y. LeeThe Surgery-First Orthognathic

3. Model Surgery Setup in the Surgery-First Approach

Jong-Woo Choi1   and Jang Yeol Lee2  

Department of Plastic Surgery, Asan Medical Center, Seoul, Korea (Republic of)

SmileAgain Orthodontic Center, Seoul, Korea (Republic of)
Jong-Woo Choi (Corresponding author)
Jang Yeol Lee

Model surgerySetupArticulatorMountingMagnetic platesSurgical occlusionWaferFinal occlusionPrematurityTooth movement

3.1 Model Setup Procedure

  1. 1.

    Mounting procedure

The Z4 dental articulator is a specially designed instrument that can be utilized for mounting dental casts for patients undergoing the surgery-first approach (SFA) (Fig. 3.1). The main components of this articulator are the detachable magnetic plates that hold the maxillary and mandibular models. The thin magnetic plates have a uniform thickness and can be stacked; the final models of the upper and lower arches are ultimately attached to a transparent acrylic plate, using conventional gypsum. Another characteristic part of this articulator is the throttling plate that allows three-dimensional (3D) control of the maxillary surgery. The regulator allows the desired surgical position of the maxilla to be simulated, without cutting the gypsum board.

Fig. 3.1

A photograph of the Z4 Articulator

  1. (a)

    Face-bow transfer

Like mounting a conventional surgical patient on a dental articulator, a face-bow application is needed to view the 3D spatial location of the maxilla relative to the rest of the skull (Fig. 3.2). Clinically, careful attention is required to compare the extent of left and right canting of the maxilla. Based on the Frankfort horizontal plane, the maxilla is positioned, and the bite fork is fixed. Often, when the vertical positions of the right and left external ear rods are different, the surgical plan may need to be calibrated.

Fig. 3.2

Clinical application of the face-bow transfer

  1. (b)

    Mounting models

First, three pairs of models are mounted onto the Z4 Articulator, using the maxillary face-bow and bite occlusion information (Fig. 3.3). One model pair is set up to allow individual tooth movements (Fig. 3.4). The remaining pairs are used to create an intermediate wafer, which will guide the later maxillary surgery, and a final wafer that will allow the final postoperative occlusion.

Fig. 3.3

Mounting models for wafer creation

Fig. 3.4

Mounting the individually cut model

  1. 2.
    Individual setup procedure

    1. (a)

      Drawing vertical and horizontal reference lines

Mar 5, 2021 | Posted by in Orthodontics | Comments Off on Surgery Setup in the Surgery-First Approach
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