# Digital Planning Technique for Surgical Guides for Prosthetic Implants before Orthodontic Treatment
## 2 Materials and Methods  
### Digital Workflow for Aligner Treatment Supported by Implants  
First, the patient is asked to undergo a cone-beam computed tomography (CBCT) scan in order to gain information about their alveolar bone measurements and the root positions of their teeth. Then, the patient is scanned using a 3-Shape intraoral scanner (TRIOS 3, 3 Shape Trios A/S, Copenhagen, Denmark) to make virtual dental impressions and prepare a setup. A setup is a virtually created visualization of the teeth after orthodontic treatment.  
The setup is prepared after receiving the scan, which is then shown to the orthodontist and surgeon in order to evaluate whether the implantation of the teeth in question is possible before starting the orthodontic treatment. The evaluation takes into consideration factors such as tooth width, implant width, and the movements of the surrounding teeth during orthodontic treatment.  
The orthodontist and surgeon decide that implants can be placed before orthodontic treatment; therefore, the dental technician makes a pontic in setup. A pontic is a virtually created dental crown of the implanted tooth in the setup which does not change in size or move during the whole orthodontic treatment. A pontic can be created using the shape of the existing tooth, if this tooth is going to be extracted. However, if there is no tooth, a pontic can be prepared using adjacent or contralateral teeth as a reference for its anatomy. Furthermore, a pontic can be created by making a wax up of one tooth, or by using standard tooth shapes adjusted for the patient.  
The pontic is then placed in the first and final stages of the orthodontic treatment in setup. A superimposition of the first and final stages is created, and the exact position of the implant is detected. When the orthodontist approves the implant position and the whole setup, the information is given to the surgeon.  
Second, the surgeon orders a surgical guide. In situations when implant surgery is planned with orthodontic treatment, a surgical guide assists in placing implants exactly where they need to be after treatment. Moreover, a surgical guide replicates the exact surfaces of the patient's intraoral setting and helps the surgeon to drill implants into the bone with optimal accuracy. When ordering a surgical guide, a surgeon must mark whether the implant surgery will be fully guided, or pilot guided. The difference in the accuracy between a fully guided and pilot-guided implant surgery is 0.2 mm, where fully guided is more accurate [6]. A surgical guide is planned by taking into consideration factors such as the system, diameter and length of the implant. Before printing a surgical guide, approval from the surgeon must be received.  
Third, the dental technician prepares the surgical guide using 3-Shape Implant Studio Software (3-Shape Global, Copenhagen, Denmark). The programme automatically generates safe zones by matching the first and final stages of the setup and uses a prepared pontic. Afterwards, the surgical guide is printed with layers 150 microns thick from 3D printing resin of photopolymer fluid material using a RapidShape P40 (Straumann, Munich, Germany) series professional 3D printer with high-volume printing. Before giving the surgical guide to the surgeon, it is made sterile by letting it sit in a bath with Globacid ID solution for 15 min and then placing it in an autoclave for 40 min on the soft programme (a maximum of 2.3 Bar) at 121 \({}^{\circ}\)C. The flow and responsibilities of guided implantation prior to planned orthodontic treatment with aligners are shown in Figure 1.