Implant Procedures 101

Many practitioners have found implant procedures to be too difficult or too much trouble to perform. Now that restorative components for most implant systems allow for cemented restorations, implant procedures for most clinical situations can be completed in two or three one-hour appointments. This article will review an easy-to-follow restorative philosophy using single- and two-to-three-unit implant restorative procedures that are similar to conventional dental procedures.

Dr. Jansen will present "Why You Should Treatment-Plan More Implant and Esthetic Dentistry" at the CDA Scientific Session in Anaheim. His presentation will be from 9 to 11:30 a.m. on Saturday, April 15, in Room San Simeon A/B of the Anaheim Hilton and Towers.

Dental-implant surgical and restorative components and dental impression materials are the top two categories of items that dentists spend their money on. More than twice as much money is spent every year on implant-related products (an estimated $175 million) than on impression materials (an estimated $80 million). However, while most practitioners use impression materials frequently, most don’t perform implant procedures. In fact, the average restorative dentist does not do implant procedures, and the average restorative dentist who does do implant procedures only performs them on two to three patients a year. Most practitioners have found implant procedures to be too difficult or too much trouble to perform. Now that restorative components for most implant systems allow for cemented restorations, implant procedures for most clinical situations can be completed in two or three one-hour appointments. This article will review an easy-to-follow restorative philosophy using single- and two-to-three-unit implant restorative procedures that are similar to conventional dental procedures.

In the past, most restorative dentists did not feel comfortable with implant procedures because of the variety designs available. Often, a restorative dentist would work with a surgeon who used a particular implant system; and, six months later, the same surgeon would be using a different system. Some surgeons change implant systems or implants within a system every 18 to 24 months because of perceived advances in design. Restorative doctors have found implant procedures difficult, the learning curve long, and office support staff unsure of how much time to allow for implant procedures or how many appointments to schedule to complete a treatment. The end result has often been an implant restoration with a lab bill that was more than expected, and frustration with the amount of time to needed complete treatment and with complications such as screw loosening. Today, with changes in restorative philosophy, implants restorations are being cemented and things are much different. Implants are getting easier to restore and more restorative practitioners will start working with them. Restoring dental implants can be very similar to doing conventional dentistry.

Posterior single-tooth restorations can be done in one restorative appointment after the implant has been placed. This is done by making a orientation guide (index) at the time the implant is placed (Figure 1). Different ways of indexing the implant at the time of surgery have been described.^2-4 Various components can be used to orient or index the implant at the time of surgery using impression copings, gold cylinders, or special indexing components, depending on the implant being used.

Figure 1. An orientation guide in place being attached to the adjacent teeth.

While an implant is being placed during the surgical appointment, the orientation or index can be made. Composite or resin can be placed on the orientation component and on several of the adjacent teeth. Once the material is set, the orientation guide is removed and set aside. The implant placement procedures are then completed. The implant is then allowed to integrate for the predetermined amount of time. The patient returns to the restorative dentist’s office for impressions six to eight weeks after the surgery. This allows for any changes in the edentulous area to be recorded. An impression of the implant can be made at the time of implant surgery, but very little information is gained about the soft tissue in the surgical field.

A cast is made from the impression of the patient after the implant has been placed. With this cast and the orientation guide made at the time of surgery, a model with an implant analog or replica can be fabricated. This model allows for laboratory procedures to be done while the implant is integrating (Figure 2). The laboratory fabricates a custom abutment (prepared tooth form) and a cementable restoration. A screw-through restoration could also be fabricated. For a posterior restoration -- where esthetics is not a concern -- the restoration is placed after the allowed time for integration. This final restoration may be placed (Figures 3 and 4) in the surgeon’s office, thereby decreasing chairtime in the restorative dentist’s office.

	Figure 2. A model fabricated using the orientation guide can represent the position of the implant in relation to the hard and soft tissues.
	Figure 3. Stage-two procedures being performed, exposing the implants.
	Figure 4. The final restoration is placed at the time of stage-two surgery.

For anterior areas, or areas of esthetic concern in the posterior, the orientation guide (index) is made at the time of surgery (Figure 1) and sent to the lab. Again, six to eight weeks after the surgery, the patient returns for an impression of the edentulous area. This is done to record changes that may have occurred in the edentulous ridge due to surgery. The lab technician needs an accurate reproduction of the soft tissue architecture. The lab uses this model and the orientation guide to fabricate a model on which the custom abutment, final metal coping less veneer material, and provisional are fabricated (Figure 5). Due to potential tissue changes, a temporary -- rather than definitive -- restoration is made.

Figure 5. Custom abutment coping and provisional made prior to stage-two procedures.

The custom abutment can be made from various materials. Prepable abutments are made from titanium, gold, or ceramic cast to cylinders made from plastic or gold, or from titanium and are computer generated (Procera, Nobel Biocare USA Inc., Yorba Linda, Calif.).

Once the implant is ready for stage-two procedures, or loading, the patient returns to the surgeon’s office to have the custom abutment placed (Figure 6). The provisional is then placed on the custom abutment. This is an excellent time for the surgeon to determine if any soft tissue modification will be needed around the restoration or custom abutment. Again, the restoration is not completed because of the unpredictability of the soft tissue. The tissue is allowed to mature around the provisional for four to six weeks. The coping that was made is stored for the following appointment.

Figure 6. Custom abutment being placed at the time of stage-two surgery

The patient leaves with a fixed restoration on the implant. No longer does the patient have a removable stayplate. In the past, one of the most difficult challenges for the restorative dentist was making a provisional for the single-tooth implant patient after surgery. The surgeon would normally place a healing abutment and have the patient continue to wear a stayplate. The stayplate would need to be modified to fit over the healing abutment, which was placed on the implant. This area of the stayplate, the acrylic tooth junction, often became weak and broke.

Once the soft tissue has matured around the provisional, the provisional is removed and the coping (the cementable restoration minus the veneer material) is placed on the custom abutment (Figure 7). A centric relation record is made, followed by an impression picking up the coping (tissue impression). Both of these are sent to the lab. There is a huge advantage in making this tissue impression with a coping that is made in the lab on a custom abutment. This allows the practitioner when chairside to be assured that even if the custom abutment margins are subgingival, the coping and tissue impression will capture the finish line on the custom abutment margin. Many claims are made by manufacturers about the ease of use of prepable abutments chairside. Not only are prepable abutments difficult to prep at the chair, but if the margin is placed subgingival, cord packing and retraction procedures around implants are difficult. There is no periodontal ligament to limit the cord or to pack against. With the above method, the coping acts as an impression coping, capturing the abutment finish line regardless of its placement.

Figure 7. Copings in place after soft tissue maturity are ready for a tissue impression.

The lab fabricates a tissue cast from the tissue impression using lab resin and a paper clip or lab bur. No implant or abutment lab analogs are needed. The lab applies a veneer material to the coping on a model that represents the mature tissue around the custom abutment. These procedures are done in the laboratory ceramic department using conventional lab procedures and conventional pricing, not in the implant department with implant pricing. This difference can reduce the lab bill. Most laboratory procedures involving implant fabrication have surcharges and cost more than conventional procedures. The final restoration is then ready to be placed on the custom abutment (Figure 8). Cotton or restorative material is placed over the screw access opening of the custom abutment. A soft (temporary) or hard (definitive) cement may be used to retain the final restoration.

Figure 8. Final restorations in place.

For multiple-implant restorations, only two or three appointments are needed. For single implants that did not have an orientation guide made at the time of surgery and multiple-unit implant restorations, the doctor will always make an impression during the first appointment after the allowed implant healing time. Only a plastic stock tray, impression material, and implant impression copings are needed. Pick-up impression copings are recommended over transfer impression copings because of their better accuracy. Corresponding healing abutments and impression copings should be used (Figures 9 and 10). Regardless of whether a one-stage or two-stage implant placement protocol is used, healing abutments should be in place.

	Figure 9. Healing abutments in place.
	Figure 10. Corresponding impression copings in place.

The healing abutments are removed and an impression coping placed. For multiple implants, one healing abutment at a time is removed, starting with the most posterior implant. Slight downward pressure and rotation is used while inserting (with fingers) the impression coping into the implant. This allows for tactile verification of proper seating of the coping/implant interface.

Radiographic verification should be made to confirm proper seating. The tray is tried in and modified accordingly to allow for the screw in the impression coping to be loosened form the set impression material. If more than one impression coping is being used and they are adjacent, they should be connected to increase the accuracy of the impression procedure. A rigid registration material is recommended (Blue moose, Parkel, Figure 11), composite or cold cure resin can also be used. The impression is made and the copings picked up in the impression tray. The healing abutments are replaced, and jaw relations (centric or maximum intercuspal position records) are made. The patient is instructed to return in 10 to 15 working days for the second appointment.

Figure 11. Pick-up impression copings with a rigid registration material connecting the two.

The impression is sent to the laboratory and laboratory procedures are begun. Custom abutments can be fabricated in an ideal fashion. For all intents and purposes, these abutments are "prepped teeth" (Figure 12). Once the custom abutments are made, no special lab procedures are done. Procedures go back to conventional dentistry at conventional dentistry lab fees. If the restoration is being placed where esthetics is not a concern, the restoration is completed. If esthetics is a concern, or the clinical situation does not dictate finishing in two appointments, a framework (Figure 13) and provisional are fabricated along with the custom abutments. If the clinical situation does not dictate finishing in two appointments, a provisional will be placed on the custom abutment after the framework is tried in. This could be the situation if there are multiple implants that will be splinted together.

	Figure 12. Custom abutments in the laboratory.
	Figure 13. Framework on custom abutments in the lab.

At the second appointment, the healing abutments are removed and the custom abutments are placed. This is done one implant at a time, starting with the most posterior healing abutment. The healing abutment is removed and the custom abutment is placed immediately. With many flat-top implant systems, the tissue can collapse around the implant, making seating of the restorative components difficult. Once the healing abutment is removed, the custom abutment should be placed quickly. Radiographic verification of proper seating of the custom abutments should be made. Once confirmation of proper seating is made, the framework can be tried in, or, if completing, the final restoration is placed. The time allotted for this appointment is close to the amount of time allotted for conventional procedures of a similar situation. If one allows 30 minutes to try-in and cement a three-unit fixed partial denture on two abutment teeth, he or she should allow a similar amount of time when trying in and cementing a fixed partial denture on two implant custom abutments. For the practitioner doing these procedures for the first time, 45 minutes should be adequate. Placement of one or two custom abutments should take no longer than five to 10 minutes.

Often, the tissue will need to mature around a provisional for the practitioner to evaluate soft tissue contours. In this situation, the provisional is placed and the coping and or framework stored for a third appointment. The patient leaves with a provisional restoration, and the tissue is allowed to mature.

Once the tissue has matured, the patient returns for the third appointment. The provisional is removed, and the framework is placed. Jaw relations (centric or maximum intercuspal position records) are done, and the framework picked up in with a tissue impression as previously described (Figure 14). The margin placement can be 1 mm plus subgingival, and no retraction cord is needed. The framework is made in the lab to fit the custom abutment perfectly.

Figure 14. Left, cross-section view of tissue impression with picked up framework. Right, resin dies in framework prior to pouring tissue cast.

Once an impression is made, the provisional is placed and the patient told to return in 10 to 15 working days. The framework in the tissue impression is sent to the lab, and a tissue model is made (Figure 15). No implant or abutment analogs are needed. Resin dies are made, and the cast is mounted in the proper fashion. The final veneer material is placed, and the restoration is completed. The restoration is now ready to be placed (Figure 16). Time allowed for the insertion procedure on multiple implants is similar to that allotted for a similar conventional procedure on multiple-tooth preparations.

	Figure 15. Tissue cast with framework removed.
	Figure 16. Final restoration completed on the tissue cast in the laboratory.

For single restorations, a final cement of the practitioner’s choice can be used. For multiple units, a soft cement such as Optow Trial Cement (Teledyne Getz, Elk Grove Village, Ill.), Improv (Steri-Oss, Yorba Linda, Calif.). or Provolink (Ivoclar Vivadent, Amherst, N.Y.) is recommended. Zinc-oxide eugenol-based cements can be used but can be more difficult to remove. Multiple-unit restorations should be removed annually to check the individual implants for mobility.⁵

Cemented restoration have many advantages and few disadvantages.^6-8 One contraindication for cemented single- or multiple-implant restorations is a restoration with very little interarch distance. If a similar situation was found in a conventional dental situation, the practitioner would use the most retentive cement available. With implant dentistry in areas where minimum retention can be achieved on the custom abutments, the option of screw retention is used. Screw-retained restorations offer the ultimate in retention. Multiple-unit implant restorations that are cemented with soft cements can be difficult to remove. A new instrument from Kavo, the Coronoflex (Kavo America, Lake Zurich, Ill.), makes removing these restorations easier.

The above procedures describe implant dentistry performed similarly to conventional dentistry. Only two or three goal-oriented appointments of no longer than an hour are needed. Most manufacturers have components that allow for these types of restorations. For practitioners who have had frustrations in the past with restorative implant procedures, times have changed. Today, implant restorative procedures can be easy for the patient, staff, and dentist.

Author

Curtis E. Jansen, DDS, maintains a full-time private practice limited to prosthodontics in Monterey and Salinas, Calif.

References

1. Personal communication. Presidents and or CEOs of Ivoclar North America, Noble Biocare Steri-Oss, Implant Innovations Inc., and Astra Tech.

2. Hochwald DA, Surgical template impression during stage I surgery for fabrication of

a provisional restoration to be placed at stage II surgery. J Prosthet Dent, 66(6): 796-8, 1991.

3. Reiser G, Dornbush JR, and Cohen R, Initializing restorative procedures at first stage surgery with a positional hex: A case report. J Perio Rest Dent, 12(4):279-93, 1992.

4. Prestipino V and Ingber A, Implant fixture position registration at the time of fixture

placement surgery. Pract Perio Aesthetic Dent 4(9):23-7, 1992.

5. Jemt T, Linden B, Lekholm U, Failure and complications in 127 consecutively placed

fixed partial prostheses supported on Branemark implants: from prosthetic treatment

to first annual check-up. Int J Oral Maxillofac Implants 7:40-4, 1992.

6. Pauletto N, Lahiffe B, Walton J, Complications associated with excess cement around crowns on osseointegrated implants: a clinical report. Int J Oral Maxillofac Implants 14:865-8, 1999.

7. Keith S, Miller B, et al, Marginal discrepancy of screw-retained and cemented metal-ceramic crowns on implant abutments. Int J Oral Maxillofac Implants 14:369-78, 1999.

8. Hebel KS, Gajjar RC, Cement-retained versus screw-retained implant restorations:

Achieving optimal occlusion and esthetics in implant dentistry. J Prosthet Dent

77:28-35, 1997.

To request a printed copy of this article, please contact/Curtis E. Jansen, DDS, 34 Dormody Court, Monterey, CA 93940.