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Inside Dental Technology
September 2014
Volume 5, Issue 9
Peer-Reviewed

Practical Implant Techniques That Will Impress Your Dentists

Little things add up when building relationships

Todd R. Schoenbaum, DDS, FACD

In addition to the obvious qualities that a clinician expects to see in restorations, the dental technician’s team has practical options to use for impressing the dentist on the next implant case. The dentist already anticipates that the restorations will have accurate and passive fit, good occlusion and interproximal contacts, and exceptional esthetics. However, restoring implants generally requires a more knowledgeable and skillful dentist, and as such, dentists are expecting more from the technician. Here are a few simple items that will help to impress upon dentist-clients that your laboratory goes above and beyond to help them achieve excellence.

Cleanliness

All too often, a laboratory sends the dentist implant crowns and abutments that have residual polishing debris, damaged and filthy model work, and fit checker and stone debris on or inside the crown and abutment (Figure 1 and Figure 2). What this says is that the delicacy and integrity of the implant site is of little concern to that particular technician and perhaps he or she is not giving the case the same level of concern that the dentist is. Cleanliness counts. The peri-implant tissues (Figure 3) are significantly more delicate than around a sound natural tooth, and keeping it free of debris is imperative.

Any debris retained also has the potential to significantly affect the fit of the abutment and the restoration. Poorly fitting abutments will increase occlusal adjustments, produce more leakage, and increase the possibility for screw loosening or breakage.

Packaging and Instructions

The packaging that technicians use to return restorations tells a story for the dentist. Before the package is even opened, the dentist gets an idea, whether true or not, about what is inside. How much does this laboratory or technician value the work? High quality and care put into the packaging tells the dentist something special is inside, something that took great skill and training to create. Poor-quality work in a fancy package won’t fool the dentist, but the packaging should outwardly reflect the care the technician put into the craft.

Most dentists have been properly trained in implant prosthodontics, but inevitably some will not have the knowledge and skill required for the cases they send to the laboratory. They may not call to ask for the technician’s help or guidance, making it good practice for the laboratory to include a brief set of directions when returning the case to the dentists. Include the following:

Abutment material

Margin positions on the abutment (i.e., -0.5 mm facial, 0 mm lingual)

Crown material

Shade prescribed

Manufacturer suggested torque value

Screw type (i.e., 0.050 hex, 0.048 hex, unigrip)

How has the intaglio of the crown been treated? (steam cleaned, etched, silanated)

Suggested procedure sequence (i.e., remove healing abutment, insert abutment and verify fit, torque to 20 Ncm or 35 Ncm, fit crown and verify contacts and margins, obturate access hole, cement crown, clean excess cement thoroughly)

Abutment material, margin position on the abutment, crown material, and shade should have been dictated on the prescription form or discussed with the dentist before the case was started. This discussion is especially important for a dentist who may be less experienced.

Fresh Clinical Screws

The screw used to attach the abutment or crown to the patient implant should never be used in the laboratory and should remain in its original packaging. Implant screws are highly engineered to produce and maintain a specific level of tension between the implant and abutment. Many have a special coating to help ensure this happens.

When clinical screws are used during the fabrication of the restorations, they inevitably stretch (the screws and threads actually stretch), become dirty (Figure 4), and lose some coating. Some damage to the screw head may occur (Figure 5). This problem is significantly more likely to result in the screw being stripped when torqued into place. All this leads to an extremely critical component being damaged or compromised. In the laboratory, laboratory screws should be used (and reused) and not sent along with the case. The dentist may find it confusing to determine which screw is which (or it could be indicated in the directions).

Access Point for Cemented Restorations

It is often said that cemented crowns are nonretrievable. This is not true. To retrieve it, the clinician must drill through some sort of porcelain, metal, and/or zirconia and may not know where to drill. To make the clinician’s job easier, the technician should mark the crown where the access would need to be if removal is ever needed. Before the final glaze of the crown, estimate the access point on the crown that would allow access to the screw channel (Figure 6). Create a small divot (~0.5 mm to 1 mm) using a fine diamond bur (Figure 7). In this depression, place a highly opaque porcelain stain (such as ochre or white) (Figure 8), apply the rest of the glaze or stain as desired, and fire. The resulting crown will now have a “bulls eye,” telling all future clinicians (oftentimes not the original treating clinician) where to drill the hole should the crown need to be accessed. It’s simple and fast, and significantly improves the ease of retrievability.

Screw-Retained Crowns

Following placement, torqueing, and obturation of the screw-retained crown, the dentist will be covering the access hole with composite. Getting the composite that covers the access to have a reasonable match to the crown (Figure 9) can be challenging. Before final delivery of the crown, it is useful to have the access hole ready to be covered. I generally prefer to cover the dark metal near the occlusal with a thin layer of A1 or A3 composite opaquing resin to minimize grayness. The porcelain surrounding the access should also be beveled and etched with hydrofluoric acid. If these steps are completed preoperatively, the crown is significantly simpler and faster to deliver.

Stained Zirconia Abutments

Even with the implant in the proper position, gingiva may recede. If this happens, it would be esthetically beneficial if the abutment resembled a normal root surface (Figure 10). The precolored or prestained zirconia helps minimize the “white stripe” effect. However, applying a zirconia stain to the surface to bring it down a few shades helps to significantly camouflage the abutment.

Conclusion

Ideally, these tips will help laboratories create stronger and mutually beneficial relationships with dentists because the little things mentioned above make treatments better for patients.

Acknowledgment

The author would like to thank Yi-Yuan Chang, MDC, for the exceptional laboratory work in Figures 6 through 8 and Figure 10.

About the author

Todd R. Schoenbaum, DDS, FACD
Assistant Clinical Professor, Division of Restorative Dentistry, Director of Continuing Education, UCLA School of Dentistry
Los Angeles, CA

Figure 1. Residual debris in the implant analog and on the abutment will prevent complete seating of the restorations. This will inevitably lead to an increase in problems with fit, contamination, and screw loosening. It may also compromise the health of the peri-implant tissues.

Figure 1

Figure 2. Residual debris in the implant analog and on the abutment will prevent complete seating of the restorations. This will inevitably lead to an increase in problems with fit, contamination, and screw loosening. It may also compromise the health of the peri-implant tissues.

Figure 2

Figure 3. The peri-implant tissues are significantly more delicate than those around a natural tooth. All reasonable measures should be taken to protect the integrity of the seal around the implant and the abutment.

Figure 3

Figure 4. Clinical implant screws are carefully engineered to ensure proper preload, tension, and torque levels. The contamination of these screws will negatively affect their reliability.

Figure 4

Figure 5. These clinical screws were being used in the laboratory during fabrication. A worn-out or incorrect driver was being used, and the screws are now nearly stripped. This would be difficult for the clinician to notice without a microscope. When he or she attempts to torque the screws into place, they will likely strip. Clinical screws should not be used in the laboratory at any time.

Figure 5

Figure 6. A surveyor can be used to approximate the location and angulation of the screw-access channel. This will then be transferred to the overlying crown.

Figure 6

Figure 7. A fine diamond bur is used to create a small divot at the location (from Figure 6) where the screw channel can be accessed at a future date if needed. Opaque porcelain stain is being placed into that depression.

Figure 7

Figure 8. Upon completion of the glaze firing, the screw-access “bulls eye” is clearly visible and any future clinician will know where to drill should the screw need to be accessed.

Figure 8

Figure 9. Well-sealed and esthetic obturation of the access channel on screw-retained restorations can be difficult for many clinicians. It can be made significantly easier by opaquing the inner metal, beveling the occlusal, and performing proper etching.

Figure 9

Figure 10. Zirconia abutments can be hand stained to resemble adjacent root surfaces. Should the gingiva recede at a future date, the implant will still appear normal.

Figure 10

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