Often seen as one of the more complex treatment options for patients with terminal dentition, restoring full arch implant bridges should be a simple and methodical process due to the state of digital technology.
Digital pre-operative planning of tooth set up, implant placement and implant capture is paramount. Following a simple workflow we can ensure all of these points are addressed to prove prosthetic delivery of a titanium/acrylic hybrid within 4 days.
Traditional techniques
Once implants and abutments are placed the traditional technique of taking impressions is time consuming and can bring inaccuracies negating the preoperative planning and surgical results.
Intra Oral Scanning Technique (IOS)
The development of IOS for full arch prosthetics is utilised more and more. The scanner pieces small images together using common 3-dimensional points. The accuracy of each image captured and the algorithms of the scanner software needs to be at the highest level to ensure all these small images are pieced together accurately. The scan path is also important in ensuring the final prosthesis will be passive. The final fit of the bridge is dependent on the type of scanner used, the implant scan bodies used and the user’s scanning technique.
Structured light Scanning
Intraoral scanners use a technology called structured light scanning, projecting a light source with different shapes over the surface of an object, calculating the distortion to determine the shape of the scanned object. If there is excess moisture or debris around the scanning sites (common at surgery), the scans become difficult and potentially distorted resulting in in-accuracy of the abutment positions.
Icam4D
Icam 4D takes stereo photogrammetry and doubles it using 4 cameras. The technology also allows the user to take multiple view angles to capture and integrate the data. This allows difficult sites like pterygoid placement easier to capture.
Using these images the data is calculated to determine the position using dots which are etched onto the scan body precisely. These dots are known to the algorithm producing a position of the implants. The advantage of icam4d photogrammetry is that we capture the images extra orally – the system can identify all implant positions at once so we avoid any errors caused by image stitching.
Because the system is only looking to identify known dots on the scan bodies the accuracy is not affected by excess moisture or debris in the scan field, therefore we can scan an arch with extreme accuracy within 20 seconds.
Planning
During the pre-operative planning stage, we use intraoral scans or impressions, photos and CBCT scans.
Alignment of the photos and the scans provides the ability to create a 3-dimentional smile design with the ideal tooth set up. Then surgical guides are produced to assist with implant surgery and abutment placement.
Surgery
Following the surgical guides implants and abutments are placed and a soft tissue and Icam4D scan is taken.
Immediate Design
The new scans and abutment positions are aligned to the preoperative design and a try in or aesthetic verification bridge is 3D Printed and tried in. A scan is taken of the bridge in the mouth and any adjustments needed are transferred to the final design.
Final Delivery
Once the aesthetics are confirmed with the try bridge the immediate hybrid bridge is designed, milled, and delivered over the next 2-3 days.
Using technology to its full capacity provides a level of confidence with full arch restorations that is unmatched and your patient will be provided with the highest possible treatment of care with superior clinical results.
Published in Bite Magazine Oct 12 23, 2023
