Controversial Issues that Effect the Dental Implant Industry
Analysis of the Shortcomings of Tri-Dental's® Matrix Implants in Contrast to GEN5™ Implants from Paragon™ Implant
March 22, 2023 | Dr. Gerald Niznick
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TRI-Dental® Implant Company started in 2014 with an implant copying many of the features of the Tapered Screw-Vent sold today by Zimvie and developed by Dr. Niznick in 1999. These include the internal hex/bevel connection (Niznick 1987 US Pat. #4,960,381), friction-fit abutment (Niznick US Pat. #5,334,024), triple-lead threads & SBM (HA) blasted surface.
The Matrix implants are available bone-level and with a 2mm concave, anodized extender, each with two platform diameter options. Implants are available in only 4 diameters ranging from 3.3mmD to 4.7mmD. For single tooth restorations, the short extension of a zirconia or printed crown engages the single vertical projection for anti-rotational stability. Multi-unit restorations seat only on the top shoulder of the implant without any internal connection to resist tipping forces during chewing. The threads of the Matrix do not get progressively deeper towards the apex for increased stability. The threads and blasted surface extend to the top of the implant which could contribute to peri-implantitis.
The Matrix implant is designed for direct attachment of the restoration to the top of the implant. It comes in a bone-level version and with a 2mm concave extension which it calls “Multi-level”. The internal shaft, which is available in only 1 diameter, has a lead-in bevel of about 10 degrees and a single projection for anti-rotation of a single unit crown. This projection is not needed for multi-unit restorations. The Matrix implants come in only 4 diameters with the 4.7mmD being thee widest. TRI Implant claims of “faster workflow, cost savings, and increased precision by 73%” are not supported by any evidence and are not realistic. Screw-retained restorations to eliminate the need for cement is nothing new and is certainly available with all implant systems. The FDA approved the Matrix Implant on the requirement “the manufacture of these abutments and restorations will be at TRI Dental Implant Int. AG. facilities.” This may preclude in-office manufacture of crowns but certainly such resin based, printed crowns will not maintain as smooth surface as a titanium abutment.
The Matrix implant with the 2mm pink anodized neck extension is misnamed “Multi-level” because it is just a single level platform. The need for different heights of abutments to accommodate for different thicknesses of soft tissue has been recognized for decades, both in Multi-unit Abutments, Overdenture Abutments and abutments for cemented restorations.
TRI Implant published an abstract of a loading study with its Matrix implant that does not comport with the loading studies required for FDA marketing approval. It only goes to 1.2M cycles with 50Ncm of load whereas the FDA required studies got to 5M cycles to determine point of failure. Such a fatigue test does not show if the crown/implant margin is opening during cyclic loading, a shortcoming of external hex implants that lead to micro-leakage and screw loosening. The Matrix “Multi-level” Implant, compared to Paragon’s GEN5+™ implant, neither offers vertical flexibility in placement and restoring, nor the high level of stability achieved with the GEN5+™ friction-fit, internal hex connection collar that can be removed to connect directly to the implant should recession occur and the metal becomes exposed.
Four misconceptions is TRI CEO’s explanation of the advantages of the Matrix implant:
1. Because of the relatively flat top surface of the Matrix implants, two implants could diverge 100 degrees and still be able to seat the bridge:
While this may be true, it overlooks the reason for angled MUAs, namely to redirect the trajectory of the prosthetic fixation screw to come through the occlusal of the prosthetic teeth in a position that allows tightening of the screw. Dr. Dunlop, in his effort to avoid the maxillary sinuses and increase the A-P spread in the lower jaw, sometimes needs to place implants at an angle approaching 50 degrees. The angled MUA allows him to redirect the fixation screw to a position that would be close to where it would have been had the implant been placed straight and parallel with the other implants, allowing easier attachment and removal of the prosthesis.
2. Because there is no abutment, the fixation screw can be made with a considerably wider diameter, adding to its strength:
While this may be true, the advantage of narrow-diameter fixation screws is that there is minimal disruption of the occlusal surfaces of the bridge. Wider screws require a wider access hole.
3. Because there is no abutment, the dentist saves on cost:
While this may be true with some systems that charge $200+ for MUA or a ASC abutment, one has to compare the cost of the Matrix implant ($275 before discounts) to other companies that have a U.S. list price of less than that for the implant and the abutment of your choice.
4. Because of the fixed 2mm height of the neck of the Matrix “tissue level” implant, the dentist can avoid having to inventory and select from a variety of abutments… thus a very thin catalog:
While this may be true, healing collars, MUAs, Locator Abutments and abutments with contoured margins for cemented restorations all come with varying cuff heights for a very important reason…. tissue thickness varies in height. It is a long-standing principal that to maintain an oral hygiene and minimize biofilm formation on an implant, it is preferable to have a smooth titanium or zirconium surface for trans-mucosal tissue contact than printed composite restorations that can be susceptible to scratching when cleaning by currents or have surface imperfections from fabrication.
The picture on the left shows the placement of Multi-level Matrix implants using a tissue punch surgical protocol. Because of the varying thickness of the soft tissue, the tops of the implants are mostly sub-gingival. This is in contrast to attaching MUAs that projects through the tissue for improved visibility.
