Implant Restorations Using Digital Workflowsby Matthew Race
Advancements in digital technology have simplified the restorative implant workflow, making treatment more comfortable for the patient by providing the clinician with state of the art equipment that allows them to achieve the levels of accuracy and efficiency that were previously difficult to consistently reproduce. We will use a real case to take a look at the simplified workflow for the clinician and explain the laboratory processes that sit in the background, between digital implant impressions and the restorative appointment to give an overview of the new and exciting digital implant workflow.
Digitising implant level impressions has obvious benefits to the clinician and patient. It is valuable for the clinician to understand the processes that sit between the clinical steps to realise the potential benefits that digitising the clinical stage has upon laboratory processes and restorative outcomes.
Fig.1 - Taking a Digital Impression of the Healing Cap
Fig.2 - Core3dcentres Scan Body
Fig.3 - Taking a Digital Impresssion of the Scan Body
Fig.4 - Final Digital Impression of the Scan Body. Geometry allows Angulation, Articulation and Rotation to be recorded.
The process begins when the clinician takes a digital implant level impression. This can be achieved a number of ways and in this particular case was performed using an iTero digital impression system combined with core3dcentres scan bodies. First a scan is taken of the implant site over the top of the healing cap. (Fig.1) A scan body is then placed on the implant and a scan is taken in situ (Fig.3). The opposing is then scanned and so too is the bite. The scan body informs the scanner of the position, rotation and angulation of the underlying implant by combining the image of the scanbody with core3dcentres implant library using the geometry for reference, indicated in Fig.4. The digital impression, shade and (optional) digital photograph are then forwarded to Race Dental Laboratory. The clinician will receive a digitally printed model, with the correct emergence profile, the analogue in place and a custom abutment and crown ready for the final patient appointment.
For the laboratory the process begins when the digital impression is received from the clinician. The file is received, the model is created and the restorative procedure evolves. At Race Dental Laboratory we use 3Shape’s design software due to its accuracy and consistent results (Fig.5 - 10). We start by designing the fully contoured restoration to fit harmoniously in the mouth and then design the customised abutment to fit within it to marry intimately between the crown and the implant fixture. This is an important difference to other systems that use off the shelf abutments or require the abutment to be designed first, meaning the crown has to be designed around the abutment leading to compromised aesthetics and function. By designing the crown first we get the optimal final restorative result and work back towards the implant itself.
Once the crown and abutment have been designed they are sent digitally to core3dcentres production centre for manufacturing and are returned within 24-48 hours. When the crown and abutment arrive back in the laboratory they are paired with the digitally printed model from core3dcentres and the relevant hardware and the technician proceeds in hand finishing the crown checking contacts, fit, interdigitation, emergence profile, marginal ridges,contours, anatomy, morphology, occlusion and colour. The occlusion is verified from a digital bite provided from the digital scan. As this is taken with no interfering material the occlusion can be set correctly every time.
Fig.11 - Printed Implant Level Model with Analogue + Ti Base in place
Fig.12 - Milled Monolithic Crown ready for Bonding to Titanium Base
Fig.13 - Articulated Implant Level Model
When a digital photograph of the natural dentition has been provided by the clinician (Fig.14), we are able to add relevant labial characterisation, wear facets and nuances and stain and glaze the restoration to harmoniously blend within the mouth.
To finalise the restoration the screw access hole is blocked out, the Ti base is sandblasted with 50 micon Aluminium Oxide at around 3Psi to create mechanical retention and then using an alloy primer, it is primed for added retention and cleansing (Fig.15). A 50/50 mix of ceramic primers A + B is then used to prime the bonding surface of the Zirconia. The two parts are then bonded together using the manufacturers instructions.
To finish we then perform a manual high lustre polish of the occlusion with extra focus on triangular ridges, marginal ridges and all working and shearing anatomy to ensure minimal wear to any opposing dentition (Fig.15).
The final result is a highly aesthetic, extremely durable Monolithic Translucent Zirconia Opalite Crown to be placed onto the implant giving the patient an outstanding implant restoration.