This post is the continuation of this last year’s post. It shows how the ridge bone grows and remodels itself around the thin neck threads of an internal hexagon ICX implant with cone-connection.
The upper second molar was extracted and the implant was placed three months later with a simultaneous internal sinus lift under low primary stability conditions. Finally, the third molar was extracted at the moment of taking the impressions for the implant crown.
Once again, you can see the beginning of this case on this post
The case was indeed very favorable regarding the amount and quality of the soft tissue, although the circumstances were right the opposite regarding the bone. Relatively good width, but scarce height and density, three months after the extraction.
This X-ray was taken on October 9, 2012, a year after setting the crown and 14 months after placing the ICX implant.
It shows how the crestal bone has remodeled itself, growing vertically around the neck threads of the implant.
The soft tissue is really healthy after one year, although the hygienic conditions surrounding the implant are certainly not the best.
Mesial tipping behind an extraction site is a normal phenomenon that can be corrected using a simple acrylic wedge and some patience, from both patient and dentist.
Here I show how to distalize a tooth in order to correct the mesial tipping without using orthodontics.
*this is the continuation of the previous post, which shows the surgical soft tissue management phase
First make your design and explain it to the patient and to your dental technician.
The goal in this case was to fit a longer disto-mesial crown on the back implant that tilts the second molar back to a more upright angle.
Notice that is is reciprocal. The crown won’t fit in the place unless the gap is made somehow bigger before the insertion.
For that we need a simple aid. That is, for example, a chairside made acrylic wedge that you make over the future crown abutments on the cast model or directly in the mouth. It can also be done in the lab, if you prefer.
There are, however, two ways to approach the solution at this point:
- You make the acrylic wedge with the actual size, then you add acrylic distal increments
- This is more precise, but it requires a second impression and thus, more time.
- You take some cast material from the mesial side of the tooth to be tipped back, then you build the acrylic wedge on the model.
- This allows to prepare the final crown and to have it ready as soon as the molar tips back and lets the crown in.
- But not valid for screwed crowns if the gap opening is more than 1″ on average.
In this clinical case I chose the second way and I gave the patient both the edge and the crowns, instructing her to take them in and out until the crowns fit in.
A second molar can hardly be tipped back if there is a wisdom tooth behind it. So I extracted the third molar and inserted the acrylic wedge on the same day.
On the hand design you may see I planned to insert the front crown and only a wedge on the back implant, but the I tested it and realized that the wedge was more stable with a double post retention. But it could have been also done with one abutment.
The wedge must adapt passively on the front and ut must have an inclined rear surface that pushes the molar back while the occlussion keeps the wedge in place.
There will be subsequently an increased bite heigth, resulting in no front contacts and premature contact on the wedge and the implants underneath.
- You may want to allow the implants a longer healing period just to assure full osseointegration.
- You need to tell the patient that he/she should not overload the implants by bitting hardly on them, and that the molar will move back gently in a few days or a few weeks, depending on different factors (bone density, extraction distally, degree of tipping vs. amount of distal movement).
- You may need to schedule some control appointments, checking how the molar moves back and the bite closes down. If that doesn’t happen, you may need to introduce some changes in your wedge design or confirm that the patient carries it at all times.
There will be a moment, days or weeks later, when the crown can be placed on the abutment and fits in with more or less pressure. This can be done by the dentist or also by the patient at home, providing he/she was properly instructed on this task. Normally it is the crown itself that pushes the tooth back the last tenths of millimiter and falls right in place.
Implants with ball retainers an Locator attachments on the lower jaw are an efficient solution to avoid the instability of a total prosthesis, especially for those patients with a big tongue (macroglosia) and little bone ridge retention.
Actually, the tongue tends to grow as we grow old, and even more when we lose teeth, because the leave more place for the tongue itself.
With the tongue movements, the prosthesis comes loose easily and that is usually uncomfortable for the patients because of the lack of confidence on the prosthesis while eating or speaking.
The lower jaw keeps normally enough bone on the anterior region, even in very atrophic cases. This case, from a 77 year-old male, shows more than enough bone kept. So 3 ICX implants, all three 15” x 3,75” were easily set on the most conveniet places of the lower anterior region.
The remainig lower left wisdom tooth was left in place. At 77 years of age and without sympoms and no influence on the therapie, it can as well stay in place.
So, after two months the healing caps are changed by ball retainers and the old prosthesis is relined in order to fit the new conectors.
The prosthesis is marked below, exactly where the contact points are.
Then comes the drilling until the prosthesis rests freeely on the gums.
Reline resin is added under the prosthesis. The patient bites in the normal position and the resin selfcures in the mouth.
The rubber rings inside the stainless steel structure can be chosen in three differente degrees of hardness and retention. They wear out like every rubber component and can be therefore easily changed.
After a few minutes cure time the retainers are already fixed and the retaining force can already be appreciated, as the prosthesis stays in the right position although the tongue and the cheeks exert the same force as before.
In this case, the three ball retainers proved not to be retentive enough for the patient. Normally a four implant solution provides a more retentive, more stable, four-point trapezoidal support. Nut the patient was running on a low budget and we had to go for a three implant display, with the central implant close to the mandibular synfisis.
By changing the three ball retainers into Locator attachments and just placing the softer plastic rings under the metal matrixes, we achieved a good degree of confort for the patient.
In this post I want to show the bone regenerating effect from the narrow threads around the neck of an implant, brand ICX, 8” long, 4,8” wide. You can see the one-year evolution control on this following post
Day O: a second molar on the left upper jaw was extracted on May 9, 2011 due to a tooth fracture. The X-ray was taken after the extraction. The wisdom tooth is kept behind to minimite the alveolar resortion.
Three months later, on August 16, 2001 the ICX 4,8″x8″ was set with 35 N primary stability, by means of a punch technique and small vertical sinuslift, using a collagen membrane and autogenous bone. The implant was set further distal to the center space, counting already on the future extraction. The wund is sealed with a platform-switch healing screw.
Two months later, on October 18, 2011, I make another X-ray check, test the stability of the implant.The bone has grown around the narrow neck threads. The bone is condensed around the apex and the impact sound is excellent, showing a good integration.
I insert the closed-impression post. Now has come the moment of the extraction of the third molar (wisdom tooth), because it is no longer necessary and, furthermore, interferes with the plastic cap that goes over the post. The impression is taken therefore after the extraction.
Nine days later, on October 27, 2011, the abutment is screwed in with 35 N torque and the crown is cemented with temporary cement until the 6-moth control.
* To see the the one-year evolution control go this post
This is a simple case of an included, not erupted, lower third molar extraction.
Incision is done down the line and around the preceding molar, as well as the vertical discharge in the middle of the vestibular side.
The flap is open and the periostium is peeled off the bone
A round drill is used with physiologic serum irrigation to remove the covering vestibular bone until the molar can be pulled off.
Luckily the molar comes out intact together with the surrounding inflammatory process.
Stitches are used to place the flap back in place.