In today’s economic environment, laboratory costs can play a factor in acceptance of treatment. A difference of a few hundred dollars may be the decision point for some patients. Additionally, this also plays a factor when dealing with PPO insurance plans that often set the allowable fee at, or below, a UCLA or CAD/CAM abutment laboratory fee as charged to the practitioner. With this in mind, in-office custom abutment fabrication can provide a high-quality abutment at a lower cost, allowing the clinician to work within the patient’s financial and/or insurance boundaries. As a comparison, an in-office custom milled abutment will typically have a cost range between $75 and $100 (depending on the manufacturer). Whereas, the laboratory fee for a UCLA abutment is typically in the $250 range and a CAD/CAM can be more than $325 per abutment.
Before the introduction of the UCLA abutment, the only abutment available was a stock abutment, which either the dental laboratory technician or practitioner would mill; this was done chairside, or on a model creating a customized abutment. Today, this is still offered in some circumstances, and manufacturers have developed what are termed “milling abutments” to allow this to be offered in more situations. A milling abutment is essentially a solid abutment that has bulk added to it. This allows one to change angles as needed when creating a custom abutment, something that may not be possible with a standard stock abutment (Figure 1). Until recently, executing this process in the office was a challenge, as the rotary instruments we had at our disposal to fit our high-speed handpieces did not efficiently cut titanium. Friction-grip carbides in a titanium abutment adjustment kit (Figure 2). Abutments (kit 4475 [KOMET USA]) are now available specifically for shaping (black ring, golden shank) and finishing (red ring) titanium. This can be accomplished either intraorally, or extraorally. The author recommends that, unless minor customization is required, it is better to customize the abutments extraorally. This article will now address the steps for extraoral abutment customization using milling abutments.
IN-OFFICE EXTRAORAL CUSTOM ABUTMENT FABRICATION
When significant abutment customization is needed, it is easier to create the abutment extraorally versus attempting to do so intraorally. This is especially true if a milling abutment is going to be used, as these require more metal be removed. The process starts with an implant impression and fabrication of a soft-tissue model. To fabricate a soft-tissue model in the office, place the analog on the impression head within the impression and inject Soft-Tissue Moulage (Kerr Lab) 3 mm around the analog’s crestal and allow to set. A stone model is then poured and models are articulated (Figure 3).
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Figure 3. Occlusal view of the stock titanium abutments showing nonparallelism. |
Figure 4. Anterior view of the stock abutments on the soft-tissue model showing nonparallelism. |
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Figure 5. The abutments are reduced using the cross-cut carbides to indicate the gingival margin and parallelism. |
Figure 6. Soft-tissue removed, casts occluded to check occlusal reduction and margins have been refined. |
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Figure 7. Occlusal view showing parallelism of the abutments with circumferential margins. |
Figure 8. View of the abutments showing parallelism. |
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| Figure 9. Occluded view of the finished custom abutments. |
Figure 10. Buccal view of the finished abutment heads. |
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Figure 11. Lingual view of the finished abutment heads. |
Figure 12. Occlusal view of the finished abutment heads showing circumferential margins. |
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Figure 13. Intraoral buccal view of the custom abutments. |
Figure 14. Intraoral lingual view of the custom abutments. |