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Early Implant Placement:
Guided or Unguided

As more clinicians move to early implant placement, we are getting a lot of questions about whether the procedure should be guided or unguided. Of course, guided implant placement is great technology, but for a clinician with years of experience doing unguided implant placement it becomes a question of not which method is better, but when is guided placement indicated over unguided. The direct answer to this question is the state of mineralization of the tissue and the clinician’s experience with early implant placement.

One of the major advantages of early implant placement over immediate placement is that the implant is being placed completely into healthy, vital, mineralizing tissue filled with active osteoblasts as opposed to a significant portion of the implant being in non-living material. When you place an immediate implant, even when using our graft material (Immediate Graft), you hope you get full mineralization to the collar of the implant. However, with immediate implants, it is not uncommon to be left with some angular defects near the coronal portion of the implant or a failure to integrate. If you are using cadaver graft material, you never get integration to the grafted portion of the implant and the graft site breaks down over time.

The following graph compares:

  • Bone loss over time for implants placed in mature bone (blue)
  • Bone loss over time for an immediate implant grafted with cadaver bone (red)
As the graph shows, grafting immediate implants with cadaver bone grafts results in progressive bone loss over time:
Literature that confirms cadaver bone does not integrate to the implant surface:
Literature that confirms that cadaver bone grafts around immediate implants break down over time:

Evidence based dentistry is a common talking point, except when it runs into dogma. Virtually every dentist is taught to pack cadaver bone around immediate implants even though good science tells us it is not supporting the implant which leads to progressive marginal bone loss over time. Yet, 90% of those reading this article will get up from the computer and go pack cadaver bone around their next immediate implant because that is what they are taught irrespective of the science against it.

Early implant placement using Socket Graft places the implant in healthy vital tissue, avoiding the important shortcomings associated with immediate implant placement.

When we discuss the timing of early implant placement, there is no time frame that is necessary the clinician needs to wait before placing the implant after extraction. The process of bone regeneration occurring in the socket is a continuum that results in healthy vital bone in the socket and on the implant. Therefore, it does not matter when you introduce the implant into this healing continuum. There are, however, practical considerations. Any time point under two weeks will present the clinician with mostly graft material in the center of the socket that is OK for implant placement, but the remaining tissue in the socket will be easily disturbed and damaged with anything other than precise drilling and implant placement. This tissue will not support pilot drills and repeated drilling to align the osteotomy will damage the early mineralizing tissue. Therefore, very early implant placement needs to be guided.

So, based on the stability of the socket tissue, anything 3 weeks or less for incisors and bicuspids should be guided. For molars, anything 4 weeks or less should be guided. These time frames are for those who are just gaining experience with the methodology and with experience, the clinician will be able to better understand which cases are acceptable for unguided placement even at earlier time frames.

There is another major factor irrespective to whether the clinician is placing the implants guided or unguided and that is the anatomy of the socket. When a molar is removed, the interradicular septum should also be removed so the osteotomy will hit solid bone near the apex. In this manner, when the osteotomy is being drilled, you are not slipping off angled bone, causing the implant to be off center. Likewise for an incisor or bicuspid, when the tooth is removed, use a side cutting bur to remove any bone that will come in contact with the implant in the coronal 50% of the socket so this bone does not displace the implant when it is placed. A good practice is to use the final burr for the proposed implant to drill out the socket at the time of the extraction.

Many of these concepts are contrary to traditional dogma. Dogma teaches us that a high torque placement in dense bone produces the best integration, but this is false. The mineralized portion of bone has virtually no blood supply and no regenerative cells (osteoblasts). The vascular supply and all regenerative cells reside in the soft tissue (stroma) between the mineralized portion of bone. Highly mineralized bone sacrifices regenerative potential for implant torque and stability. In addition, dense mineralized bone has very few and often no active regenerative cells because they are “resting” and need to be awakened to produce integration. However, this is not the case with early implant placement because you are placing your implant in tissue filled with millions of actively mineralizing osteoblasts.

With our new understanding, let’s apply this knowledge to a few cases.

In this case, a molar was extracted and grafted with Socket Graft Injectable. This scan was taken 3 weeks post extraction at the time of membrane removal and implant placement. Incipient mineralization is identifiable in the extraction socket. This case illustrates why at 3 weeks after extraction the implant placement needs to be guided. At three weeks, the mineralization is not easily identified at the crest, so unless the case is planned and guided, the clinician will have no clinical indication as to the depth of placement of the implant. Also, the presence of the interradicular septum would make using pilot drills nearly impossible to drill the osteotomy cleanly without slipping off the septum damaging the newly mineralizing tissue in addition to displacing the position of the implant.

Day of placement.
The implant was placed guided 3 weeks after extraction. 35 NCm of torque. While the placement is excellent, even with being guided, it does appear that the interradicular septum did cause the implant to be displaced a small degree to the mesial. This is why we advise removal of interradicular septum at the time of extraction.
This image was taken 5 weeks after implant placement. The torque reading is now 74. In 5 weeks, the degree of torque has doubled. This increase in torque proves the ability of the grafted socket to rapidly produce integration to the implant surface.
14 months after being in function, mineralization at the crest is excellent. The excellent result of this case was largely dependent on it being planned and placed guided.

Another molar case of early implant placement demonstrates when an unguided placement can produce excellent results.

5 week early molar implant:
Pre-op
Note the dense interradicular septum
3 weeks post extraction and grafting with Socket Graft Injectable. The mineralization is nearing the crest. Note the interradicular septum had been removed to within a few mm of the root apex.
5 weeks after extraction
Membrane removal 5 weeks after extraction and day of implant placement.
After removal of the membrane, we applied cotton gauze soaked with an antimicrobial solution to reduce bacteria on the surface of the implant site.
Day of implant placement, 5 weeks after extraction.
The crest is evident as is the gingival margin. The clinician can measure the distance from the crest to the top of the gingiva to determine the depth of implant drilling. There is approximately 4 mm of gingiva over the crest (see arrows). Therefore, when determining the depth of drilling for the osteotomy, incorporate the 4 mm of gingiva to the length of the implant to provide for the proper depth marking on the drills. For example, if the implant is 11 mm, add 4 mm to compensate for the thickness of gingival margin so you will drill to the 15 mm mark on your drill.
Excellent placement of the pilot drill was a result of removing the interradicular septum at the time of extraction, which allowed for the pilot drill to reach a flat surface of bone at the apex of the socket. The degree of mineralization also stabilized the pilot for taking alignment radiographs.
Day of unguided implant placement.
Placing the implant at the time of membrane removal and implant placement with a healing abutment maintains gingival volume for improved esthetics and oral hygiene. The gingiva present at this time frame would be lost if the implant placement is delayed 3 to 6 months, resulting in poor esthetics and difficult oral hygiene due to the shrinkage of gingiva. With the healing abutment flush with the gingiva, the gingiva is maintained with little chance of contact, therefore avoiding possible failure to integrate. While an accelerated time frame is beneficial to both the patient and the clinician, this is not the main motivating factor for the patient. When the patient learns that the implant is placed without incisions, flaps, exposure of the bone, or sutures, they then insist on early implant placement.

For early implant placement, the time of implant placement and the time between placement and restoration is continually evolving as clinicians continue to use shorter time periods. The first case, performed by Dr. Matt Bickel, shows placement 3 weeks after extraction and provided excellent integration 5 weeks after placement. At this time, implant placement at 3 weeks after extraction and restoration at 4 weeks after placement appears to be a reasonable goal.

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