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Ball implants vs Locator attachments as effective solutions for an unstable overdenture prosthesis

Ball implants vs Locator attachments as effective solutions for an unstable overdenture prosthesis

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.
4-implant, Ackermann bar, mandibular overdenture

4-implant, Ackermann bar, mandibular overdenture

This case shows the placement of four implants immediately after extractions, and the final rehabilitation with a denture over an Ackermann bar.


Several years’ edentulism has left ridge bone collapsed.

The only places where the implants can be set are exactly where the four remaining teeth are.

But it even in these places the cortical layers are very thin and concave. There are even bone defects after the extractions, too.

On the left side, I fill the gaps between corticals and implants with Bio-Oss bone graft and cover it with a Bio-guide resorbable collagen membrane fixed by the healing screws.

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On the patient’s right side, more of the same. Thin, almost transparent, concave corticals, leaving groove defects after extractions. Same procedure, as before. Graft and membrane.

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Two week’s healing, prior to removal of stitches, and Ackermann bar screwed over the implants.

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Clamps under the denture hold onto the bar.

IMGP9604 IMGP9603 Prosthesis by Dr. Jon Igaralde, DDS