“Try to make a 3D-printed shell complete denture for a complete arch reconstruction”

A new case series has documented the testing and use of 3D-printed shell complete dentures as a diagnostic tool in implant planning and provisional restoration fabrication to expedite full-arch restoration. Dental Tribune International spoke with lead researcher Dr Francisco X. Azpiazu-Flores of the Department of Prosthodontics of the Indiana University School of Dentistry in Indianapolis in the US about how the research highlights the potential of this approach to simplify and streamline the process and to save clinical and laboratory time, offering enhanced aesthetic outcomes and functional results.

Dr Azpiazu-Flores, what are 3D-printed shell complete dentures?
The 3D-printed shell complete denture is a diagnostic appliance. Its main purpose is to define the position of the future artificial teeth at the desired vertical dimension in centric relation, all indispensable elements for a successful full-mouth restoration with dental implants. The anterior tooth position is defined with the shell complete denture, and the incisal edge position can be modified digitally in the 3D-modelling software during the design stage by using intra-oral and extra-oral photographs as a reference, or if needed, it can be adjusted chairside using dental composite to achieve the aesthetic outcome the patient wants. After defining these parameters and validating them intra-orally, patient satisfaction should be optimal.

Can you elaborate on the accuracy of 3D-printed shell dentures in replicating aesthetic and functional features such as incisal edge position, midline alignment and occlusal plane orientation?
The shell complete denture can preserve the aesthetics of the patient’s existing prosthesis if these are adequate, and if changes to the artificial teeth are required for either functional or aesthetic purposes, they can be modified digitally or chairside. The incisal edge position, midline and occlusal plane orientation can be adjusted by adding or removing material as needed to this diagnostic appliance. Since this appliance is only meant to help visualise and define the desired prosthetic contours, the clinician can adjust extensively without concerns about the adjustments affecting its long-term durability.

“It is a straightforward method.”

What challenges have you encountered with the digital workflow when creating 3D-printed shell dentures for full-arch restoration? Are there specific cosmetic considerations or adjustments that are more difficult to manage compared with traditional methods?
A possible limitation of the shell complete denture is that, if it is made from a complete denture with unstable posterior occlusion or deficient anterior tooth relationships and the clinician is not able to identify and adjust this digitally or chairside, these unfavourable elements can transfer to the shell complete denture and subsequently to the planning of the dental implants, leading to imprecise implant planning and placement. Additionally, learning how to use the modelling computer program requires time. However, most dentists nowadays are very familiar with using such software, so the learning time shouldn’t be too great.

How do 3D-printed shell complete dentures affect facial and lip support compared with the conventional method? Are there specific techniques you use to ensure optimal aesthetic outcomes for soft-tissue support?
Facial and lip support are important parameters whenever rehabilitating edentulous patients. Traditionally, flangeless complete dentures or artificial tooth arrangements are used to evaluate these parameters. With the 3D-printed shell complete denture, once the artificial tooth position has been defined and validated intra-orally, a 3D-printed flangeless appliance can be created using the contours of the artificial teeth of the shell complete denture. This requires an additional appointment; however, it is a required step for full-arch restoration of the maxilla.

Is there anything else you would like our readers to know about this case series or any other research you are working on?
I would like to encourage them to try to make a 3D-printed shell complete denture for their next full-arch restoration with dental implants! It is a straightforward method that will make their work easier. Also, I encourage them to expand the applications of this technique by customising the design of the appliance to fit their clinical scenario!

Currently, I’m working on other protocols to accelerate restoration with multiple or single implants. If readers are interested in checking them out, they can refer to my ResearchGate profile.