Pre-milled Abutment
A pre-milled abutment blank is a mechanically manufactured post that attaches to the superior portion of the implant where it protrudes through the gingiva, and on which a restoration is fitted. The pre-milled abutment blank allows dentists, implantologists and prosthodontists to use their in-house milling equipment to produce a customized abutment for each patient. The most common material used to fabricate pre-milled blanks is titanium, although cobalt-chrome (CoCr) is also currently gaining popularity.
Creating customized abutments in-house using a pre-milled blank is more efficient and less expensive over the long term than using a stock abutment. While the initial investment of in-house milling equipment is substantial, the return on investment over time and improved accuracy and reliability of customized abutments makes manufacturing them on-site well worth the initial costs.
Stock abutments, on the other hand, are pre-manufactured, standardized designs that can work well in straight-forward restoration scenarios and are a more cost-effective solution on an individual piece basis. Customized abutments are recommended in more complex restorative scenarios such as front-tooth restorations, cases where angulation correction is necessary, or in cases where suboptimal gingiva height risks reduced esthetic results. Customized abutments are also known to have improved biomechanical strength and connection geometry, as well as reduced risk of misfit over stock abutments. These factors have driven an increase over the recent decades not only in in-house milling, but in the variety of pre-milled implant abutment blanks manufactured.
While abutment characteristics such as collar height and angulation can be customized using in-house milling equipment, pre-milled abutment blanks are available in various platform sizes (narrow, regular and wide) and connection types (conical and hex). Past platform width and connection type, pre-milled blanks can be prepared according to the needs of each restorative scenario.
Advantages:
- Cost-effective
- Highly efficient
- Fewer number of visits required
- Easy to fabricate
- Most of the preparation for customized abutments is done outside the mouth
- Improved biomechanical strength and connection geometry
- Reduced risk of screw-loosening
- Prevention of esthetic problems otherwise encountered with stock abutments
- Improved emergence profile
Indications/Contraindications:
Pre-milled abutment blanks are indicated for most restorative scenarios.
Contraindications for the use of customized abutments milled in-house from pre-milled blanks include scenarios where:
- Patients are not medically fit for surgical procedures
- There is insufficient interocclusal space
- Splinting of more than three implants is needed in a single quadrant
- Angle correction of greater than 30° is required by an implant
- Collar height is less than 1 mm below the gingival margin
- Functional loads cannot be safely supported
- Esthetic risk exists due to translucent prosthesis materials or low gingiva height
Restoration information needed to create a customized abutment:
- Diameter of the implant system
- Cuff height
- Interocclusal height
- Needed angulation of the abutment
