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1 Quintessence copyright. You are not allows to show or use this file for any other purpose than personal use. P. Tardieu November Radiological Templates A radiological template is a radiopaque duplicate of the provisional tooth setup. This template is worn by the patient during the CT scan. The radiopaque images of the desired tooth set-up will be visible in the CT data. Having the tooth set-up information in the same images as the patient s anatomical data enhances the implant clinician s ability to plan the implant treatment. Both clinical and esthetic considerations can be incorporated. We can note that the radiological template has a variety of names, including scan prosthesis, scanning template or CT-appliance. To let the prosthetic outcome drive the implant treatment plan requires secure and precise preparation and planning. First the final position, size and number of teeth have to be determined. Second this information can be incorporated into the radiological template and worn during the CT scan. The resulting images provide a blueprint for treatment planning. Third number, size and type of implants, position and orientation can be fully analyzed during the next steps of implant treatment planning. Objectives of the Radiological Template The main objective of a radiological template is to visualize the diagnostic tooth set-up in the CT images. In addition, the template, when properly designed, can also include soft tissue surface and crestal defects. There are a variety of formulas for creating radiological templates and after years of trials, mistakes and improvement we developed the concept and fabrication of the ScannoGuide. The ScannoGuide is a radiological template which incorporates tooth information, as well as soft tissue detail in the base plate when required. 3. ScannoGuide From years of data, the formula for creating a new template was developed. This radiological template has advantages in all steps of the implant treatment planning process. 1. For the CT scan, the ScannoGuide: - stabilizes jaws - defines the alignment of the jaws for proper orientation 2. For implant planning, the ScannoGuide: - provides visualization of the teeth that need to be replaced - defines the longitudinal axis of teeth - illustrates the overall volume of teeth to replace - outlines tooth position in relation to surrounding anatomical structures - helps in determining missing volumes at the level of teeth - allows for determination of soft tissue height - differentiates tooth information and soft tissue 3. For the surgery, the ScannoGuide: The Art of Guided Implantology 1/14 Chapter 2 Diagnosis and Planning

2 - provides necessary information for the creation of a mucosa supported surgical guide. 4. For immediate load procedures, the ScannoGuide: - provides critical information for fabrication of a temporary immediately loaded bridge. 5. For the restorative phase: The ScannoGuide can be used, removing or adding the buccal flange, to check if the final restorative work will require a flange or not to support the lip. Appearance of the ScannoGuide in the CT images The radiographic template can be visualized in both the 2D and 3D reformatted CT images. The concentration of barium sulfate (BaSO 4 ) used in creation of the ScannoGuide determines the level of visibility. It s important to remember that concentrations which are too low will result in a lack of visibility of the template in the CT images. And, concentrations of barium which are too high can cause artifacts and minimize proper visualization. It is possible to vary the concentration of barium between the teeth and the base plate of the ScannoGuide, so that both parts can be visualized separately. Because teeth and base plate information have different densities of barium, they can be separated into individual 3D objects using the SimPlant Master s segmentation software. These distinct objects can be made visible or invisible within the SimPlant Planner software to allow for precise treatment planning. An 0.8 mm diameter hole can be drilled along the longitudinal axis of the tooth. This hole will appear black in the CT images and is clearly visible in 2D cross-sectional reconstructions. The following pictures illustrate what can be seen using a proper ScannoGuide in 2D and in 3D. Fig e Fabrication of a ScannoGuide Barium sulfate (Micropaque HD Oral, Lab Guebet) is used for digestive radiological exploration and is harmless for patients. It comes in a powder form and can be obtained from radiology facilities. The barium sulfate powder is mixed with the resin powder in a specific ratio. It is important to develop a gradient because this allows a separate mask of the teeth and a mask of the base. For the ScannoGuide, a mixture of 30% w/w barium sulfate is used for the The Art of Guided Implantology 2/14 Chapter 2 Diagnosis and Planning

3 teeth and a mixture of 10% w/w barium sulfate is used for the base plate. The mixture needs to be vigorously shaken before use to avoid dense spots of barium sulfate in the template. Dense spots of barium sulfate can cause artifacts in the CT images. The procedure for the fabrication of ScannoGuides is based on the same concept but using different protocols. 1. Edentulous cases Prepare acceptable denture or wax-up First, determine if the current denture is acceptable for the patient, in terms of lip support, occlusion, esthetics, etc. If the denture meets the requirements of the restorative clinician and the patient, we make an impression of the denture in silicone. Second, if the current denture is not acceptable in terms of tooth set-up, a new denture, or at least a new wax-up, must be made. The tooth set-up should reflect the final expected results in terms of lip support, occlusion, phonetics etc. Third, if the existing denture is unstable a reline using a hard resin material is mandatory prior to using the denture as a model. Fig_ Accepted denture in the patient s mouth. Silicone impressions of the denture A silicone impression of the patient s accepted denture will become the mold for the ScannoGuide. To take an impression of the underlying surface of the denture in silicone, 7 cups of silicone impression material should be sufficient. It s important that no voids remain under the flange of the denture. Do not include the flange inside the impression material. The Art of Guided Implantology 3/14 Chapter 2 Diagnosis and Planning

4 Fig_ Silicone impression Fig_ Silicone impression material Fig_ Using a scalpel, create small notches around the model for proper realignment later in the process. Fig_ Fig_ Fig_ The Art of Guided Implantology 4/14 Chapter 2 Diagnosis and Planning

5 Brush the model (avoiding the denture) with a glycerine lubricant to aid separation. Use the same mixture of silicone to form the top of the impression. Form a tight fit so there are no voids. Fig_ After setting, the two parts of the mold can be separated and the ScannoGuide process can begin. The ScannoGuide Process Because it s possible for the ScannoGuide to be transformed into a temporary denture after the CT scan, two different cold-polymerized resins are used in this process. If the temporary denture is not needed, the ScannoGuide can be created with a single colored resin. In this case: tooth-colored resin (Unifast GC Ivory) for the teeth and pink resin (Pro Base Cold, Ivoclar) for the baseplate, are used. For the tooth-colored resin mixture, combine cold-polymerizing resin, with 30% barium sulfate (Micropaque, Guerbet) by weight (70 grams resin/30 grams barium sulfate). The resin powder and barium sulfate must be vigorously shaken to ensure a homogenous mix. Measuring and blending need to be performed carefully, since the final result is affected by the concentration of barium. Insufficient barium sulfate will result in teeth not clearly visible in the CT scan and, conversely, excess barium sulfate will create artifacts in the images. Usually these mixtures are prepared in advance in the lab so that it is not necessary to make a new mix every time we have a ScannoGuide to fabricate. Fig_ Barium Sulfate powder The Art of Guided Implantology 5/14 Chapter 2 Diagnosis and Planning

6 The barium sulfate-resin mixture must be fluid enough to easily flow into the impression. Fill the entire tooth volume with the mixture. It s important to avoid air bubbles. Let this harden in a steam pot with hot water at 2 Bar pressure for 5 minutes. Fig_ Fig_ When the resin has completely hardened, remove it from the mold. Carefully trim the excess barium sulfate mixture away from the cervical contours of the teeth. Fig_ Fig_ Return the trimmed teeth to the silicone mold and gently cover with the opposite half of the mold. It may be necessary to further trim the teeth to verify a snug fit of the two parts. If there is any interference, trim the excess resin leaving the teeth in the mold to avoid damaging the model during manipulation. Fig_ Fig_ The Art of Guided Implantology 6/14 Chapter 2 Diagnosis and Planning

7 Fig_ Fig_ For the baseplate, prepare a 10% w/w barium sulfate mixture with the pink cold-polymerizing resin (Pro base Cold, Ivoclar). Combine 90 grams resin with 10 grams barium sulfate powder. The barium sulfate has a tendency to sink because of its weight, therefore it is important to thoroughly mix the ingredients. First, fill the flange area, then continue to fill the section covering the teeth. Press the two halves of the mold together manually and remove any excess resin. Secure the two halves with a rubber band and place Fig_ Fig_ Fig_ Remove the hardened model from the mold and trim any excess pink resin. Then drill holes from the center of the occlusal surface of each tooth down to the base using a Largo drill #3, following the long axis of each tooth. Fig_ Fig_ Fig_ Polish and finish the ScannoGuide to improve the appearance for the patient. Have the patient try the guide and confirm stability. For any problems of adaptation or stability in patient mouth, the ScannoGuide can be relined. When relining the ScannoGuide, the same pink mixture of resin and barium sulfate is crucial. Be sure to get a homogenous barium sulfate density and to extract the exact outline of the soft tissue. If regular, non radiopaque resin is used, the ScannoGuide will be stable, but the necessary information about the exact outline of the soft tissue surface will not be visible. Stability is essential at this step for several reasons. First, the patient must be confident in wearing the guide during the CT scan procedure. The correct fit will guarantee proper data is transferred into the scan images. Secondly, the location of the ScannoGuide determines the soft tissue contours for the mucosa supported surgical drill guide (SurgiGuide, see Chapter XX).. The Art of Guided Implantology 7/14 Chapter 2 Diagnosis and Planning

8 The patient must be instructed on how to position the ScannoGuide in the mouth and how to stabilize the guide by biting on 2 cotton rolls or on a bite template. Fig_ Proper positioning of the ScannoGuide at time of CT scan. Having the patient bite on cotton rolls has several advantages, it allows arches stabilization during CT scan, it gives a better comfort to the patient who can bite on something solid and it separates jaws avoiding artifacts from the opposite arch. There is also another way the make the patient stabilize the ScannoGuide using a resin or a radio transparent bite template including an outside extension the help the radiologist orient the Scout view in an easy way. Fig_ This kind of appliance allows the radiologist to align the patient without seeing what is inside the mouth. Appearance in the CT images The axial view clearly shows the image of teeth with open hole through. Fig_ The Art of Guided Implantology 8/14 Chapter 2 Diagnosis and Planning

9 Images of the 3D representation of the ScannoGuide: base plate and teeth in separate 3D objects. Fig_ Fig_ Fig_ Images of the ScannoGuide can be related to the ScannoGuide itself and to the original denture also. Fig_ Fig_ D images of the ScannoGuide in combination with the bone information: Here is an example of a full lower case fabricated in the same way. Fig Fig A duplicate of the accepted denture of the patient is performed to fabricate the ScannoGuide. The Art of Guided Implantology 9/14 Chapter 2 Diagnosis and Planning

10 Fig d - Fig c Fig b Fig a We can interact with three different masks: the mask of the bone, the masks of the base and the mask of the teeth depending what we need to hide or what we need to show. As we ll explain later, the use of these mask not only allows choices in implant placement, but also abutments size and type with realistic images. 2. Partially edentulous cases First, the desired tooth set-up must be determined. Both the restorative clinician and implant surgeon should share in this decision making process. A wax up of the teeth to be replaced is made on the patient s plaster cast, according to the restorative project. Using wax for the teeth is generally faster than using radiopaque teeth; however, either design is workable. Each case requires attention at this step because it will drive the whole restorative and implant process. In this case the space is too small for 3 teeth but too big for 2 two teeth. The decision has been made to place two implants and to distribute the volume with a normal sized lateral incisor, a normal sized premolar and to use the residual space for the canine. The mesial side of the The Art of Guided Implantology 10/14 Chapter 2 Diagnosis and Planning

11 canine is kept intact and the distal is reduced to keep an aesthetic effect showing teeth that look like real sized. Fig_ Make an impression of the wax up using silicone putty impression material. Fig_ Fig_ Remove the wax using hot water or steam. Apply separating fluid over the edentulous area, using a brush. Fig_ Fig_ Prepare a 30% mixture of tooth-colored resin (Unifast) and barium sulfate (Micropaque) by weight (70 grams resin/30 grams barium sulfate). The resin powder and barium sulfate must be vigorously shaken to ensure a homogenous mix. Measuring and blending need to be performed carefully, since the final result is affected by the concentration of barium. Insufficient barium sulfate will result in teeth not clearly visible in the CT scan and, conversely, excess barium sulfate will create artifacts in the images. Fill the entire tooth volume with the mixture. Replace the silicone mold over the plaster model and fix it into place with rubber bands. Place in a pressure-cooker with hot water and 2 Bar of pressure for 5 minutes. The Art of Guided Implantology 11/14 Chapter 2 Diagnosis and Planning

12 Fig_ Fig_ When the resin has completely hardened, remove it from the mold. Carefully trim the excess barium sulfate mixture away from the cervical contours of the teeth. Then drill holes from the center of the occlusal surface of each tooth down to the base using a Largo drill #3, following the long axis of each tooth. Use a drop of cyanoacrylate glue to stabilize the teeth on the plaster cast. Fig_ Fig_ To create the ScannoGuide, a transparent hard thermoplastic foil of 1.5 mm of width Euko Dur from Erkodent is used. The hard foil is heated and applied over the plaster cast using the OmniVac system for thermoplastic foils. When completed, the transparent resin is kept all over resin teeth and it is cut at 1.5 mm beyond the occlusal surface of teeth of the plaster cast. The thermoplastic foil is radio transparent and there is no need to make holes again through it. Fig_ Fig_ The Art of Guided Implantology 12/14 Chapter 2 Diagnosis and Planning

13 Fig_ Fig_ Have the patient try the guide and confirm stability. Stability is essential at this step. The patient must be confident in wearing the guide during the CT scan procedure. The correct fit will guarantee proper data is transferred into the scan images. As for the full cases, the patient will be trained to stabilize the guide biting on two cotton rolls or on a bite template. Appearance in the CT images ` Fig_ The 3D reconstruction of the CT images of a ScannoGuide shows the teeth set-up for this partially edentulous case Material Pink resin: Self curing denture base material monomer, Triplex cold Ivocal Vivadent Self curing denture base material polymer, Triplex cold Ivocal Vivadent Tooth-colored resin Unifast Trad, Ivory, Powder and Liquid. GC Dental Products Corp , Torimatsu-Cho, Kasugai, Aichi, Japan Baryum Sulfate Micropaque H.D. Oral Guerbet LARGO Drill 6x #3 The Art of Guided Implantology 13/14 Chapter 2 Diagnosis and Planning

14 Dentsply. Maillefer Zetalabor, Hard Laboratory, high precision, condensation silicone Zhermack Separating Fluid, Ivoclar Thermoforming foils, ERKODUR, Erkodent x 125 mm, Thickness 1.50 mm Super GLUE-3, Loctite Henkel France SA, 161, rue de Silly Boulongne Billancourt France The machine T&S Dental & Plastics Co. Myerstown PA USA The Art of Guided Implantology 14/14 Chapter 2 Diagnosis and Planning