Protocol to Digitized Removable Denture

In this blog, I will resume the steps process to produce digital denture, it will help you with dicision making to go completely digital, or to combine both methods, traditional and digital procedures. When the clinician know his options, he will take a bold step without worrying. 

Let’s see what metadata says:

• Digital complete dentures are suitable for all skeletal relationships 
• Arbitrary articulators are sufficient
• There is no evidence that any impression’s method is superior
• scanning strategy is crucial to successfully acquire data records 
• Combined methods for clinical stages are possible ( refers to previous blogs to learn more)
• The CAD- CAM’s denture fabrication can be done by various protocols based on clinical steps required
• A trial printed prosthesis is available if needed
• Milled method is always better to choose specially for patient with Aesthetic concerns

Depending on the clinician confort level, and the patient needs and his specific health condition, the digital denture can be produced successfully. Studies state high levels of patients’ satisfaction.From one to two appointments, or three to four appointments, choose what serves better your patient.

Focus  

The steps to digital plan includes: a digital Imaging and Communication in Medecine File known as a (DICOM file), an intra oral scan, or PVS impression, a digital teeth setup, and a digital manufacturing. The planning implant placement on the software and the fabrication of surgical guide are also steps that can be done digitally too. Depending on the case, choose the best protocol for the best outcomes.

Before to start your plan, it is important to prospect about available methods and systems utilized by the laboratory. Knowing what the  laboratory services are, is primordial. Not all laboratories have full services for digital production. You should Keep informed about the methods of manufacturing and the systems used, you can ask your laboratory what they are using, and what are your options.

 

Just by choosing Digital denture design and manufacturing as an option for your treatments, numbers of appointments are reduced with superior fit. This is a one step, or two steps production indicated to fast replacement of the denture. By one call from your client, it is almost done, isn’t it amazing!!

• Using digital data, already available without repeated procedures
• Using old denture to create data, and replace the old denture 
• Produce an immediate denture for nursing home patients, medicaly compromised patients, and other cases as evaluated by the clinician.

During the two steps protocol, in the first appointment the interocclusal record is registred and scanned with an IOS scanner if availble. The data electronically sent to the laboratory for manufacturing, new denture is produced and sent back to the clinician for delivery, done.

• For clinicians, planning for implant, you can use digital prototype denture as a reference to radiographic guide and to produce a surgical guide too. It will help with 3D placement of the implants. D’une Pirre deux coups, as we say in French 😄, the data generated can be used as a guide for framework fabrication and milling method of the definitive prostheses. 

What about relines and adjusments associated with IOS use? Metadata states that it is not recommended due to a need of repeated adjustments of the intra and extra borders of the denture  bearing tissues.

Reline and adjustment with this method will not let you achieve an optimal fit of the digital denture. It is important to use conbined methods for relines to enhance the stability of the denture. Use traditional impression, data acquisition scan in laboratory, and digital manufacturing.

These methods of one and two steps protocol may not be recommended for clinician with patient looking to improve the aesthetic, the prostheses may not have the desired result.  Clinician needs a try-in procedure to have an approval from the patient to avoid any disappointment. Use the option of three, or four steps protocol.

Where there is no need to rush, it is better to use traditional methods for data acquisition. This means using traditional impression (master casts) and bite blocks/rims for records, then transfer it to digital records. This is a case for four appointments protocol. A prototype denture can be tested before producing the final denture, the clinician will be able to make changes as required. In three steps protocol, all is degitized for trying on the set up. 

How it works? Digital denture’s production includes three basic steps protocol, 

• Data acquisition using IOS 
• data processing using CAD
• prosthesis manufacturing using CAM

The choice for the steps process will be determined by Assessing the OVD loss, which includes the pre- treatment records: incisor height measurment, phonetic evaluation, vertcal dimention in resting position, interocclusion distance, incisal display at rest, facial third assessment. The Facial analysis, which includes the mid-line, the closest speaking space, the occlusal plane, the highest lip-line, the tooth lengh, position, and inclination, the tooth shape and shade, and the tissue shade.

The three steps protocol, in the first appointment master impretions are made based on the existing denture, or using thermoplastic, the heat modabble stock impression trays. The mold selection and the facial analysis for the existing denture done in the same appointment, all sent to the laboratory.

If an Intraoral scanner available records should be done in this appointment and sent to the laboratory on DICOM file. It is important to check with the laboratory or with the manufacturer the mold teeth availability.

The second appointment, a trial denture sent by laboratory to the clinician, it’s a digitally printed bases with posterior molars teeth, the anteriors teeth are set on the occlusal rims already done by computer for the upper and lower denture. These are to be validated by the clinician and the patient. The phonetic is to be assessed too. The validation of the set-up includes the mid-line, canines positions, smile line, and highest lip-line. The laboratory sets digitaly the central incisors at 12 mm anterior to the posterior border of the incisive papilla, and the canine tips on the line that passes through the Centre of the incisive papilla. According to the upper seated teeth, the lower is set over the crest of the ridge. The occlusal plan is estimated based on the retromolar pads, the hamular notches, and the incisal edges. Once the clinician validates all and send back the bases, if any changes made, the laboratory uses an extraoral snan as he did for the casts models and manufacture digitally the future prostheses. The last appointment is for delivery, where the dentures are ajusted, finished, and polished. 

Refer to the blog Digital Removable Denture Methods to choose for your patient, the method for manufacturing for the final denture. You will find a great advices and a well explanation of all the systems.

In the case of four appointment protocol, this is similar to traditional method, the second appointment is for molds and shade selection, for data acquisition with the creation of (DICOM file). Occlusal wax rims are ajusted exactly like in conventional method followed by trying on set up in the third appointment, For the final appointment, you can choose to print the denture, or make a trial with prototype denture before printing the final denture, in this case you will add one appointment.

Note, that digital primescan methods for the intraoral scanner to be googled, the stategy you use to record data is very important to avoid repetitive procedures, it should be done in three minutes as one of the pacific conferences said😄. All in one time, and avoid moving scan many times on the same region, this will create many layers, the system can’t read it. This apply to extra scanner too. 

refer to the blog’ photo.

The trial bases will be clinicaly ajusted, the wax occlusal rims are used to reccord the inter-relationships, it will be digitized using extraoral scanner. The files are integrated to the case, and all is ready to CAD phase, the design. As I said previously, in this step you can choose to print the prototype.

The CAD ( stereolithography) file, STL is sent to milling software that directs the milling machine CAM, to perform series of movement and produce the desinged denture. This is the most used method to produce dental prosthesis denture. You can read more in my previews blog on the procedures.

If you are planing purchasing a 3D printer, have advices from expert. Look at the services after sales, if the trainings and support services are included, the ease of use of the printer, the space available in your clinic, the footprint, the consumables, the post curing/ the post washing, the material used if it’s hollow or solid, the maitenance guide, accessories gloves & masks. The printer should be set before starting to print, to avoid re-do.

You can make an order for counselling for more information.

Hope this blog helped you and answered some of your questions, don’t hesitate to contact me for advices. I will be more then happy to serve you, thank you for reading me, and I am thinking to make an FAQ available to resume all the digital denture process in one blog.

Stay connected , thanks.

References

The Terms CAD- CAM stand for computer- aided design & computer- aided manufacturing.

www.nassdeviceservices.com, 

www.dentalcare.com/en-us/ce-courses/ce662

https://www.pdconf.com/ncs2024/