This article aims to detail the case requirements for making the final, implant-supported prosthesis on multi-unit abutments (MUAs). It can be used, with minor differences, for implant-level prostheses as well. The workflow is separated into conventional and digital; both of which will be outlined below.
Conventional Workflow (No IOS)
Conversion Model + Prosthesis Duplicate
If a conversion model and a prosthesis duplicate are available, the only requirements will be:
- Impressions of the arch for soft tissue and MUAs (no transfer copings).
- Impressions of the opposing arch.
- Bite registration.
Preliminary Impressions
If no conversion model nor prosthesis duplicate are available, an open-tray, preliminary full-arch impression needs to be taken at the abutment level. Another impression of the opposing arch should also be taken. A third impression of the patient’s existing prosthesis is required, as well as a bite registration with the opposing arch.
Verification Jig & Wax Rim/Jaw Relationship Records
Taking a verified final impression is a key step to ensure workflows success. An implant verification jig, then a custom tray, should be used to take the final impression.
When trying in and adjusting the wax rim, verification of midline, incisal edge position, lip support, smile line/occlusal plane, vertical dimension of occlusion (VDO), and phonetics are required.
Bite registration after fully contouring the wax rim and measuring the VDO is needed.
Provisional Implant Prosthesis (Test Drive)
One screw test should be verified. The provisional stage allows the patient to “test drive” the restoration. At this point, final occlusal adjustments/modifications can be made and recorded in an impression then sent back to be duplicated in the final restoration.
The patient’s feedback should be evaluated and recorded. The color and shade of the final restoration should be confirmed as well.
Delivery of the Final Restoration
The provisional restoration should be returned to the lab so that minor occlusal adjustments could be implemented in the final CAD/CAM design. The final prosthesis is milled from a block of monolithic zirconia, without the need for veneering material, offering maximal resistance to wear, chipping, and fracture.
Digital Workflow (IOS)
Conversion Model + Prosthesis Duplicate
If a conversion model and a prosthesis duplicate are available, the only requirements will be:
- IOS of the arch for soft tissue and MUAs (with and without scan bodies).
- IOS of the opposing arch.
- Bite IOS.
Preliminary Digital Impressions
If no conversion model nor prosthesis duplicate are available, a scan body IOS is taken at the abutment level, as well as an IOS of the opposing arch. An IOS of the patient’s existing prosthesis should also be taken and bite scans with the opposing arch.
PMMA Try-in/Jaw Relationship Records
One screw test should be verified.
When loading and adjusting the try-in, verification of midline, incisal edge position, lip support, the smile line/occlusal plane, vertical dimension of occlusion (VDO), and phonetics are required.
Bite IOS after full adjustments and confirming the VDO is also needed.
Provisional Implant Prosthesis (Test Drive)
One screw test should be verified. The provisional stage allows the patient to “test drive” the restoration. At this point, final occlusal adjustments/modifications can be made and recorded in an impression then sent back to be duplicated in the final restoration.
The patient’s feedback should be evaluated and recorded. The color and shade of the final restoration should be confirmed as well.
Delivery of the Final Implant-Supported Prosthesis
The provisional restoration should be returned to the lab so that minor occlusal adjustments could be implemented in the final CAD/CAM design. The final prosthesis is milled from a block of monolithic zirconia, without the need for veneering material, offering maximal resistance to wear, chipping, and fracture.
How to Fast-Track the Workflow
Both conventional and digital workflows will be fast-tracked if we obtain the following:
- Scans/impressions of existing fixed temporary prosthesis.
- Conversion Model(s) [available to order].
- Duplicate of the fixed temporary prosthesis [available to order].
- Photos of the patient’s smile wearing his or her existing prosthesis.
By using a conversion model, the process of implant verification can be skipped.
PMMA prosthesis duplicate allows the patient to walk out with their temporary restoration while we use the duplicate to convert the provisional implant-retained prosthesis into the final temp.
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