SURGICAL MODEL ACCURACY DEVICE 25 years - manufacturing and distribution - around the globe research - design - manufacturing - distribution
2 SMAD - SURGICAL MODEL ACCURACY DEVICE SMAD has be designed specifically to enable the orthodontist to create accurate and precise acrylic splints, which serve as a guide to recognize when the patient is ready for surgical intervention. Precisely and independently modify oral and maxillofacial surgical models Modify model in single millimeter and degree steps Create exact surgical splints safely and precisely on the dental model before surgery J K L M I H F G E O N S R V P Q D C B U A W T X All dental segments can be moved independently with the precision orthodontists and surgeons have been looking for. A. System Base. B. Guiding Axes with the Height Recording Scale. C. Occlusal Plane Inclination Screw. D. Height Fixing Screw. E. Occlusal Plane Inclination Recording Scale. F. Multidirectional Adaptation Appliance (MAA) Height Fixing Screw. G. Occlusal Plane Transverse Inclination Recording Scale. H. Multidirectional Adaptation Appliance (MAA). I. Surgical Simulator Plate Sagittal Adjusting and Fixing Screw. J. Surgical Simulator Plate Fixing Screw. K. Occlusal Plane Transverse Inclination Adjusting and Fixing Screw. L. Occlusal Plane Inclination Fixing Screw. M. Central Sagittal Axis. Surgical Simulator Plate Sagittal Movements Recording Scale. N. Anterior Segment of Segmental Osteotomy Simulator. O. Surgical Simulator Plate. P. Surgical Simulator Plate 1: Anterior Segments Movement. Q. Surgical Simulator Plate 1: Posterior Segments Movement. R. Surgical Simulator Plate 2: Fan expansion. S. Surgical Simulator Plate 2: Rotation Movement. T. Accessories for Segmental Osteotomy Simulation with Vertical Displacement. U. Model Holder. V. Rotation Simulator Plate. W. Model Fixation Screw. X. Screwdriver.
3 PRINCIPAL MOVEMENTS POSSIBLE WITH THE SMAD Dr. Pablo Echarri Eng. Claus Schendell Dr. Martín Pedernera The Adenta LAB TEC system, designed by Echarri and Schendell, includes the Model Maker (MM, for creating study models), the Set-Up Maker (SUM, for creating setup models), the Occlusal Plane Reference (OPR, for correcting setup models and for positioning brackets for indirect bonding), and the Surgical Model Accuracy Device (SMAD, for performing model surgery in cases treated with orthognathic surgery) Model Maker (MM) Set-Up Model Maker (SUM) Occlusal Plane Reference (OPR) Surgical Accuracy Device (SMAD) According to Arnett and McLaughlin the Seven steps of cephalometric treatment planning (CTP) for surgical cases are: Step 1: Correct torque of the upper incisors Step 2: Correct torque of the lower incisors Step 3: Position the maxillary incisors Step 4: Auto-Rotate the mandible to 3 mm of overbite Step 5: Move the mandible to 3 mm of overjet (A/P movement) Step 6: Set the maxillary (upper) occlusal plane Step 7: Access the chin height and AP projection to TVL (True Vertical Line) Arnett and McLaughlin, through their facial and cephalometric analysis, set the standards for what the ideal position for each element is, which translates into orthodontic movements (Steps 1 and 2) that must be performed in presurgical orthodontic treatment, and movements that must be performed in orthognathic surgery (Steps 3 to 7). When planning the case, Dr. Echarri recommends creating setup models using the SUM and correcting the torque of the incisors, as well as the alignment, leveling, and rotation of the upper and lower teeth using the OPR. This will give us an insight into how the teeth should be positioned in order to prepare the patient for surgical treatment. The corrected setup models will be fitted with an acrylic splint, which we call a diagnostic guide, and will serve as a guide to recognize when the patient is ready for surgical intervention. The OPR can also be used to position brackets on the model if an indirect bonding technique is used. When the patient is ready for surgical intervention, new impressions and images will be taken and mounted on the articulator. The next step is to perform the model surgery, which must accurately reproduce the planned surgery in order to create the surgical guides, which will guide the surgeon during the operation. The SMAD allows simple, quick, precise, and safe linear and angular movements in the upper and lower study models, while maintaining the interocclusal relations of the articulator or adjusting them according to the treatment plan. In an article of this length, only a brief explanation of the principal movements possible with the SMAD will be provided. Le Fort I (LFI) maxillary surgery can be classified as follows: A/P Vertical Sagittal Rotation Horizontal Rotation Advancement Downgraft Impaction Steepening (Clockwise rotation of the upper occlusal plane) Flattening (Counter Clockwise rotation of upper occlusal plane) Center the midline Segmental LFI Two pieces (transversal expansion) Three Pieces (Transversal - A/P - Vertical movements)
4 Mandibular surgery (Sagittal Splint) can be classified as follows: A/P Sagittal Rotation Horizontal Rotation Canting Advancement Set Back Clockwise Rotation Counter Clockwise Rotation Center the midline Leveling Genioplasty or Chin Implants* *Not planned with the SMAD The normal protocol for cases treated with orthodontic care and orthognathic surgery is detailed in the table below. Orthodontic / Orthognatic Surgery Cases Model Maker (MM) Case History Clinical examination Study Models (MM) X-Rays Photographs Lab steps Clinical steps Orthodontic Set-up Models (SUM) Set-Up Model Maker (SUM) Orthodontic Set-up Correction (OPR) Occlusal Plane Reference (OPR) Diagnostic Splint Pre-Surgical Orthodontic Treatment Model Surgery (SMAD) Surgical Accuracy Device (SMAD) Surgical Splint Orthodontic Surgery Detailing Orthodontic Treatment
5 The SMAD acts as a universal base (1) for the MM, SUM, and OPR with the Model Holder (2). The Multidirectional Adaptation Device (MAD)(3), which allows controlled movements in all planes, and the SMAD plate (4), which holds the model and also allows displacement and segmentation in all planes. (Figure 1) (Figure 4) (Figure 1) Le Fort I Advancement: After presurgical orthodontic treatment, impressions and images are taken and mounted on the articulator. (Figure 2) (Figure 5) (Figure 2) The upper model with the articulator mounting plate is fixed to the base of the SMAD with the Model Holder, and a silicone impression of the teeth is taken using the SMAD tray. This silicone impression of the model accurately records the dental position of the teeth and the occlusal plane (Figure 3). A horizontal incision is made in the base of the model (Figure 4), using the SMAD the maxilla is advanced by the predefined number of millimeters (Figure 5). The displaced model is fixed to the plaster base with plaster and is returned to the articulator in order to make the surgical guide (Figure 6). (Figure 6) Figure 7 shows a diagram comparing Le Fort I surgery in progress on a patient, and using the SMAD. The displaced segments on the patient and the model are shown in red, and the screw that must be manipulated to perform the displacement is shown in green. (Figure 3)
6 (Figure 4) Le Fort I Downgraft: (Figure 7) Le Fort I Canting Leveling: (Figure 9) The procedure is exactly the same; presurgical models are fitted to the articulator, the upper model is transferred to the SMAD with the mounting plate, silicone impressions of the upper teeth are taken, and a horizontal incision is made in the base of the model. To bring the maxilla down, turning the screw shown in green and vertically displacing the maxilla by the planned number of millimeters is sufficient (Figure 8). Next, plaster must be added to fix the model to the base, then the model is returned to the articulator and the surgical guide is created. To correct maxillary transverse inclination (Canting), turning the SMAD screw shown in Figure 10 is sufficient, which allows maxillary rotation in both directions in the frontal plane. (Figure 10) Le Fort I Segmental in two pieces Expansion: Once the upper model is fixed to the SMAD plate with silicone, a horizontal incision must be made in the base, as well as a sagittal incision at the midline of the base. The SMAD plate will allow the transverse expansion of one or both segments by the planned number of millimeters, as can be seen in Figure 11. Asymmetric expansion is also possible, with greater posterior rather than anterior expansion, as can be seen in Figure 12. (Figure 8) Le Fort I Clockwise rotation Steepening: Following the same procedure and once the upper model is fixed to the SMAD plate with silicone and separated from its plaster base, the sagittal rotation screws (shown in green) must be rotated to rotate the maxilla as indicated in Figure 9.
7 (Figure 13) Not represented in graphic: Anterior and posterior segments can also be moved parallel individually. (Figure 11) Mandibular Sagittal Splint Advancement The procedure for mandibular advancement is the same as the procedure for maxillary advancement. The lower model is transferred to the SMAD, a silicone impression of the teeth is taken, the base of the model is sectioned, and the segment is moved forward by the planned number of millimeters (Figure 14). (Figure 12) Le Fort I Segmental in four pieces: Following this exact procedure, the SMAD plate allows the independent movement of up to four segments of the maxilla, as can be seen in Figure 13. This example shows the posterior expansion and horizontal adjustment of the anterior segments. Independent vertical movement of each of the segments is also possible, and can be combined with a vertical or anteroposterior movement of the entire maxilla. Mandibular Sagittal Splint Set Back: (Figure 14) For mandibular setback, the lower model is fixed to the base with the Model Holder, but the SMAD tray must be advanced by a sufficient number of millimeters before the silicon impression is taken to allow retrusion. Then proceed in the manner explained above (Figure 15).
8 (Figure 4) Mandibular Sagittal Splint Counter Clockwise rotation: (Figure 15) Figure 16 shows the procedure for mandibular rotation; turning the sagittal rotation screws shown in green is sufficient. Rotations can be combined with anteroposterior movements of the mandible. Mandibular Sagittal Splint Canting - Levelling: (Figure 17) Figure 19 shows the frontal plane mandibular rotation for leveling of the lower occlusal plane as well as the mandibular edges. (Figure 18) Due to length restrictions, only some of the possible movements have been described in this article, but one can conclude that all of the movements are performed in a simple, accurate, controlled manner and are completely reproducible, facilitating the creation of high-precision surgical guides. Their creation is also very fast and low cost. (Figure 16) Mandibular Sagittal Splint - Horizontal Rotation - Center the midline: Figure 17 shows the horizontal rotation to center the indicated midline to correct facial asymmetries. This movement can also be combined with other mandibular movements in the sagittal or horizontal plane. In this way, although the axis of rotation is uncertain, the planned facial aesthetic can be achieved.
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