Intra-oral pick-up of Tibases depends on the pick-up material completely encasing the Ti base and engaging the undercuts. This can be tricky! One little tip I learned from Dr Kenneth Kurtz is to pre-polymerize the parts prior to pick-up. The benefit to this is that you've added pick-up material around the Ti base in a clean and controlled environment, perfectly engaging the undercuts. Then, with the parts in place, ready for pick-up, the pick-up material need not engage undercuts, but simply make contact with the pre-polymerized material on the Ti bases. Check out this photo as evidence of this principle:
You see that Ti base second from the right? There is less than 50% coverage of the pick-up material of the Ti base? Without precoating, this Ti base would not have picked up inside the denture, and even if it had, it would not have been stable. However, there is a thin layer of pre-polymerized acrylic around that Ti base. Because I had precoated the Ti bases, all four of those Ti bases picked up and were rock solid stable! Pre coating is a MUST! Here is an easy way to pre-coat the Smart Denture Conversion Ti Bases with a thin and uniform coat:
This is my favorite way to do a mandibular pick-up. Prepare adequate depth wells to accommodate Smart Denture Conversions Ti bases secured to the multi-unit abutments with the Separable Fasteners. Cut the LINGUAL flanges and distal extensions of the denture so that the patient can rotate into the prepositioned mandibular denture in ideal occlusion with the upper denture. "Bond" the denture to the opposing dentition/denture/prosthesis using a small amount of Triad gel on the canines and first molars (you may need to use the Triad Bonding Agent). Be sure any part you don't want to be picked up in the denture are blocked out with Kool-Dam, by Pulpdent (i.e., sutures or parts of the multi-unit abutment exposed above the gingiva). Now, inject your pick-up material of choice into the intaglio of the suspended mandibular denture and around the Ti bases being picked up. Manipulate the patient closed into centric relation using chin point guidance being sure the patient doesn't deviate from centric relation during the cure time. Once material is cured, chip the Triad gel nubs away and remove the lower denture from the multi-unit abutments and proceed with the laboratory process to complete the prosthesis. Voila!
See how the mandibular denture has the lingual flanges removed and I also removed the distal extensions. This particular case also had the buccal flanges removed, but that isn't necessary, nor preferred in an immediate situation. The buccal flange serves as an indicator of appropriate vertical dimension.
One thing I love about Smart Denture Conversions is that I can use it either at time of surgery (if stability allows) or after a period of osseointegration. Today I converted a maxillary denture to fixed provisional on 5 implants. The implants were placed six months ago and due to insufficient primary stability, we placed healing abutments instead of loading. Today, I removed the healing abutments and placed 17 degree MUAs on the 3 anterior implants and 30 degree MUAs on the 2 posterior implants. Because the tissue had conformed to the straight healing abutments there was a significant amount of tissue "bunching" up over the MUAs. Because the separable fasteners are very low torque, I couldn't use the separable fasteners immediately on the 2 posterior implants. I placed the 3 anterior Ti bases with the separable fasteners and the 2 posterior Ti bases with the normal prosthetic screws (so I could torque it and be sure for complete seat.
I then sent the patient for a panoramic radiograph while I stepped to the adjacent operatory and extracted a tooth for another patient (#7 if you wanted to know). When the panoramic was completed, I reviewed it and saw that the Ti bases were completely seated. Sufficient time had elapsed for the tissue to relax around the 2 posterior Ti bases, so I switched out the normal prosthetic screws for the separable fasteners. Now the tissue was not impeding the separable fastener from completely seating the Ti base. Ready for pick-up. Today I used Sterngold's EZ Pick-up which is a bis-GMA product and requires preparation of the denture with a bonding agent light cured in the Triad 2000 curing unit for 2 minutes. I used 2 syringes: 1 was used by my assistant to fill the denture while I used the 2nd to inject directly around the Ti bases in the patient's mouth. Denture was inserted and patient set the bite. We waited a full 5 minutes. Removed the prosthesis with no troubles and began our laboratory phase.
We used this as our final impression as well, so I made a master cast and duplicated the prosthesis on the master cast with alginate to later be digitized with my lab scanner (Straumann Series 7). It's actually less patient time in the chair for me to do it this way than to do the digitization with the patient in the chair. However you choose to do it, be sure to index the master cast prior to any scanning or duplicating. This will greatly assist the design phase.
So, we now have everything we need to submit to the lab for the final prosthesis, but first we are going to play around with design to try to improve some of the patient functional and esthetic concerns. We will do this simply with inexpensive 3D printed prototypes until the patient "buys off" on the proposed design. Luckily the patient wants to flare the teeth a little and move them anteriorly which should improve the screw access channel on the mandibular left anterior implant which currently comes straight out the facial of #24. (Not a big deal in the interim with Smart Denture Conversions because I didn't have to destroy the tooth in the conversion process!)
I'm frequently asked about taller ti bases for the Smart Denture Conversion Kits. The issue is that generally with All-on-X cases, there is excessive tissue resulting from significant bone reduction. Transosseous sutures resolve the tissue issue and make the pick-up of shorter Ti bases much more predictable. Short Ti bases require less adjustment of the denture which results in faster procedure and stronger prostheses. Here is a simple technique for doing the transosseous sutures.
Although I don't have the data to support this scientifically (yet), I am convinced that the monolithic polymethyl methacrylate (PMMA) denture is the best denture to use for a conversion prosthesis (rather than a denture with denture teeth or teeth that are adhered to a denture base, or even a 3D printed denture.) I found a pretty easy way to make a denture in preparation for the the conversion prosthesis combining the ease of CAD/CAM and convenience of injection molding (Ivobase). Enjoy the slides:
Here you can see the teeth made out of Alike PMMA and then Ivobase denture base acrylic injection molded to the full arch of teeth. Note the lack of porosity in the Alike teeth and Denture Base material. The acrylic in the intaglio area is Alike PMMA used to pick up the Smart Denture Conversion Ti base. You can see porosity in that acrylic, but also note the homogeneity of the prosthesis.