In this issue:
Choosing an Implant Surgery Method Based on Indication – Case of the Week: Episode 166
Author
Note: The Hahn Tapered Implant System is now known as the Glidewell HT Implant System
In the Case of the Week for Episode 166 of “Chairside Live,” I decided to explore two cases to compare and contrast different implant surgery methods: guided and freehand. Each method has its pros and cons, with many factors to consider. Read through the following cases to see how I utilized each method.
Case #1: Guided Surgery
Figure 1: A patient presented with an edentulous space in the area of tooth #31, which had been missing for many years.
Figure 2: I had the lab fabricate a surgical guide based on an intraoral scan and a cone-beam computed tomography (CBCT) scan. After seating the guide on top of the adjacent teeth, I’m ready to begin the surgical process.
Figure 3: I use a tissue punch to remove the soft tissue and gain access to the surface of the bone.
Figures 4a–4d: To place the Hahn™ Tapered Implant, I use a spoon and a sleeve to guide each one of the osteotomy drills. The drills follow a step-by-step protocol, with each diameter slightly wider than the previous. As the diameter increases on the drill, I switch to a larger diameter spoon in order to create the osteotomy accurately.
Figure 5: The step-by-step process creates a very nice, clean site for implant placement.
Figures 6a, 6b: Now that the osteotomy has been drilled, I can connect the Hahn Tapered Implant to a specially designed implant mount, which allows the implant to be delivered through the surgical guide.
Figures 7a, 7b: I like to use a torque wrench to place the implant. Doing it by hand enables me to back the implant out of the osteotomy and redrill it if necessary until I reach the proper depth, as long as the bone density permits.
Figure 8: The implant is in position and ready for placement of a healing abutment.
Figures 9a, 9b: As healing abutments are available in many different heights, I like to measure the tissue and select the abutment height based on the soft-tissue thickness and how far I want the healing abutment to extend.
Figure 10: A radiograph shows the implant and the healing abutment in place.
Figures 11a–11c: After four months, the implant is fully integrated into the bone, and the patient is ready to return for impressions. I remove the healing abutment and place the impression coping for a traditional impression. Alternatively, I could have placed an implant scanning abutment at this time, and then scanned the implant and adjacent teeth for the final impression.
Figure 12: I use traditional medium-body impression material for the implant, soft tissue and adjacent teeth. I pick everything up with a tray filled with heavy-body impression material and, before sending the case to the lab, I verify that all of the vital details are captured.
Figures 13a, 13b: After taking an impression of both arches — as well as a bite registration — the case is ready to be sent to the laboratory for fabrication of the final restoration.
Figures 14a, 14b: At the next appointment, I remove the healing abutment once again and seat the screw-retained BruxZir® Solid Zirconia crown. As with the delivery of any crown, I check the mesial and distal contacts, as well as the occlusion, with the implant crown.
Figure 15: Because this is a screw-retained restoration, I torque the final delivery screw to 35 Ncm.
Figures 16a, 16b: In delivering the final restoration, I cover the screw-access hole with a suitable material, followed by composite.
Figure 17: Once my assistant finishes curing the composite on top of the implant, I check the occlusion one more time.
Figures 18a, 18b: A before-and-after comparison of this guided surgery case highlights the function and esthetics that have been returned to this formerly edentulous space.
Case #2: Freehand Surgery
Figure 19: This patient presented with a failing implant in the area of tooth #30. The implant itself was placed very well and the patient had a stock abutment with a cementable crown.
Figure 20: Cement extrusion is the likely cause of the extensive bone loss around this implant. As you can see in this picture, there is a ring of cement at the junction of the stock abutment and the final restoration.
Figures 21a–21c: I remove the implant, with the goal of placing a Hahn Tapered Implant at the site in a few months’ time.
Figures 22a, 22b: Once the implant is removed, I graft the site, which involves opening a flap and placing bone graft material.
Figure 23: After the four-month healing period, the patient is recalled for implant placement. A flap is created in the site, revealing that the bone has healed and the patient is ready to receive a new implant.
Figures 24a, 24b: I create an osteotomy for the Hahn Tapered Implant. Utilizing a CBCT scan, I am able to measure the exact size of the implant.
Figure 25: With the use of parallel pins, I verify the direction and angulation.
Figures 26a–26c: A radiograph further confirms direction and angulation, allowing me to finish creating the osteotomy with different-sized osteotomy drills.
Figures 27a, 27b: When placing the implant, I prefer a torque value greater than 35 Ncm to indicate the stability of the implant.
Figure 28: The implant is in place.
Figures 29a, 29b: I place a healing abutment, then suture the tissue around the implant and the healing abutment.
Figure 30: With two interrupted sutures in place, I try to create primary closure to help with the healing process. The patient will be brought back in for a final impression after about three to four months of healing.
Figures 31a, 31b: Once the implant has gone through a period of osseointegration, the patient returns for an impression appointment, which begins with removal of the healing abutment.
Figure 32: After I’ve placed the impression coping — and once my assistant takes a radiograph to confirm the impression coping is seated properly — I’m ready to move forward with the final impression.
Figures 33a–33d: I prefer to utilize a medium-body vinyl polysiloxane material and then pick that up with a heavy body. I don’t like to use light body because of the movement of the impression coping and the implant analog within the impression. So I want to make sure that I have a more solid, stronger material to hold onto the impression coping.
Figure 34: A BruxZir Anterior crown, milled right here at Glidewell Laboratories, is ready to be delivered. With an average flexural strength of 650 MPa, BruxZir Anterior is strong enough for a posterior restoration. I was comfortable choosing this material for the final crown.
Figure 35: I torque the restoration into place and place a suitable material and composite to cover the screw access.
Figure 36: I’m going to check the occlusion and make sure the crown is slightly out of occlusion.
Figure 37: Occlusal view of the restoration.
Discussion
Freehand surgery, where a flap is reflected and the implant is placed according to the available diagnostic information, is a cost-effective approach that is advantageous in many cases. When case circumstances indicate that freehand surgery can be safely and predictably executed, the approach will appeal to patients and doctors alike due to the reduced cost and chair time. On the other hand, guided surgery, in which the osteotomy is created with the aid of a digitally designed and printed surgical guide, has the potential to afford the highest level of precision and control. The superior level of accuracy afforded by this approach makes it ideal in situations where there are concerns related to bone volume or the proximity of vital patient anatomy; however, the increased cost and time associated with fabricating the surgical guide may not always be warranted.
Both guided and freehand surgery have their place in modern implant dentistry. The circumstances of each case and the situation of the patient ultimately dictate which approach is most appropriate. For each case, a cost-benefit analysis should be conducted to assess whether the necessity for added precision justifies the increased expense and added chair time of guided surgery.
