Dental implant treatment is an increasingly popular solution for replacing missing teeth. As a result, more clinicians are dedicating time and resources to training in the most advanced techniques and investing in up-to-date technology. Most clinicians have a preference for specific implant systems and components, and this familiarity with one or two systems increases confidence when recommending dental implant treatment to patients. The components used in treatment are continually evolving as newer techniques are developed. The implant abutment is particularly important, providing the interface between the implant and the prosthetic restoration. Implant abutments have to offer long-term strength, high stability, excellent biocompatibility, and resistance to corrosion. Previously, clinicians often chose stock abutments, but more are turning to custom milled abutments. The benefits of customized abutments are recognizable, especially when restoring anterior teeth.
What Are the Advantages of Custom Milled Abutments?
Custom milled abutments have many advantages:
- They help achieve a passive fit
- The final restorations are manufactured to the patient’s exact gingival architecture, achieving an optimal emergence profile and a more esthetically pleasing outcome
- It is easier to correct the angulation of the implants
- Fewer chair-side adjustments are required, and appointments can be smoother and faster, helping to increase the efficiency of a dental office
Custom abutments may be milled from titanium or from zirconia.
Designing and Manufacturing Custom Milled Titanium Abutments
Custom abutments are manufactured in several different ways. One of the most common ways utilizes CADCAM manufacturing technology. Before this, custom abutments were created using a plastic sleeve, which allowed the technician to develop a wax-up in the desired abutment form.
Presently, computer-aided virtual design technology has rendered the wax-up unnecessary. Instead, the master cast is generated from an implant-level impression that includes the soft tissue contours situated around the implant. The master cast and opposing cast are scanned and virtually articulated using design software. Virtual design allows the technician to create an abutment specifically for each patient. Using design technology, it is even possible to create virtual crown shapes to guide the design of the abutment, allowing the technician and clinician to visualize all anatomic aspects of the final restoration. Once the design is complete, the files are transferred to a milling machine, where a titanium blank or rod is milled into the custom-designed abutment. Virtual files allow multiple abutments to be created, so the patient can wear a nice provisional crown while the technician still has a duplicate to create the final restoration. But, this treatment approach will incur higher costs for the clinician, and ultimately for the patient.
After a titanium abutment is milled, it is hand finished if required. The extent of finishing depends on whether the abutment has been produced with its retentive grooves and surface anatomy or whether these will be contoured before polishing. Often CADCAM technology provides superior surface finishes compared to hand polishing.
Why Choose Titanium Abutments Coated with Titanium Nitride?
Titanium abutments can also be coated with titanium nitride, giving the abutment a gold hue. Clinicians may desire a gold-hued surface when esthetics are an important consideration. When tissue is thin, a naturally colored titanium abutment shines through the gingival margin, negatively affecting the esthetic outcome of treatment. Using a titanium abutment with a gold hue ensures that the gingival tissues are not discolored. However, this type of abutment is not suitable for use underneath all types of all-ceramic crowns. Abutments coated with Titanium nitride are not suitable for use with e.max crowns or with high translucency zirconia.
Manufacturing Custom Milled Zirconia Abutments
Custom milled abutments can also be manufactured from zirconium rods. The demand for zirconia abutments is increasing and they can be a good option for cases where esthetics are particularly important and where the patient has thin gingival tissues. Crowns and bridges can be fabricated using higher translucency materials when tooth colored abutments are chosen.
The zirconia used to manufacture custom abutments is stabilized with yttrium trioxide. This stabilized form of zirconia has excellent mechanical properties and is highly suitable for use in the mouth. The behavior of the stabilized zirconia is very similar to stainless steel and it has a flexural strength of approximately 1200 to 1300 MPA. For comparison, the flexural strength of PFMs is approximately 1400 MPA. Stabilized zirconia can resist cyclical loading stresses and its white color can be modified to mimic the natural shades of teeth. Zirconia abutments can be kinder to the peri-implant issues compared with titanium and the risk of an inflammatory reaction is decreased.
Custom abutments provide a good workable solution for clinicians wishing to achieve an optimal treatment outcome for the patient. They allow clinicians to carefully manage the soft tissues, thus creating a more desirable emergence profile. It’s easier for the patient to maintain oral hygiene when gingival tissues are correctly contoured. Patients frequently regard dental implant treatment as a premium service, and, as such, they expect to receive implant restorations that meet these demands. Custom milled abutments ensure that implant-supported restorations are esthetically pleasing and have excellent functionality. Clinicians moving from using stock abutments to custom abutments will almost certainly find improved implant treatment results.
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