SCREW-VENT
IMPLANT AND PATENTED INTERNAL CONNECTION
- 1986
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1986
Screw-Vent Implant: Dr. Niznick
introduced the Screw-Vent® implant
in grade 1 commercially pure titanium
[Figs. 1]. The Screw-Vent incorporated
the same thread design and diameter
(3.75 mm) as the Brånemark implant,
but featured a 1.5 mm-deep internal
hexagon with a threaded shaft below
it. This patented connection provides
the stability needed between the implant
and the abutment to prevent screw
loosening and thus minimizes long-term
prosthetic complications. It also
allows screw-retained, two-piece abutments
to interlock with the internal hexagon
to prevent rotation, which made single
tooth replacement a viable option
in implant restorations. At the top
of the internal hexagon, a lead-in
bevel helps stabilize the abutment
against lateral forces and reduces
the chance of tissue being trapped
in the joint, which could result in
incomplete seating.
of the abutment. In 1992, the male
hexagon of the mating abutment was
tapered one and one-half degree to
create frictional engagement with
the internal hexagon of the implant.
This patented friction-fit connection
eliminates abutment tipping and wobble,
which are major causes of screw loosening
in other systems. Today, Paragon Implant
Company offers the industry's only
five-year guarantee against loose
screws. |
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Evolution
of the Screw-Vent and Competing Internal
Connection Implants:
The Screw-Vent
continued to evolve from 1986 through 2000
(Fig. 3). It was first offered in grade
1 commercially pure titanium, but is now
offered in titanium alloy. New Screw-Vent
diameters and surface options have also
been introduced. By 2000, the implant ultimately
evolved into the Tapered Screw-Vent with
triple lead threads. This new design further
simplifies insertion and increases initial
stability in soft bone by a patented surgical
protocol of inserting the tapered implant
into a straight socket.
The
Implant Industry Eventually Copied Dr. Niznick's
Patented Internal Design: Dr.
Niznick's internal, anti-rotational, screw-retained
connection is acknowledged as being the
most stable connection in the industry.
Over the years, numerous implant manufacturers
have attempted to copy this patented feature
in one form or another. After ensuing litigation
and/or arbitration, the following companies
have either obtained licenses on the patent,
or have been legally compelled to refrain
from making products that infringe Dr. Niznick's
U.S. Patent 4,960,381: Calcitek, Lifecore,
3i®, Steri-Oss, Straumann, Astra, Altetec,
Park Dental, Sapkos Implant Company and
Osteo-Implant Corporation (OIC®). A number
of foreign companies that manufacture Screw-Vent
clones have also been prevented from selling
their products in the United States, such
as four Israeli companies, Alpha Bio, Hi-Tech,
MIS and Medigma, and the German company,
Bego. Friadent and Straumann obtained licenses
on Niznick's internal wrench-engaging patent
in 2000. Steri-Oss developed the internal
Tri-Lobe internal connection in 1998 and
Nobel Biocare acquired Steri-Oss in 1999.
Its ads featuring the Replace Select implant
claimed that "Internal connection -
what every dentist wants".
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TRADEMARKS:
Core-Vent, SwissPlus,
Screw-Vent, Advent, Bio-Vent, Micro-Vent,
Friction-Fit, Dual Transition Selective
Surface are now Implant Trademarks of Zimmer
Dental Implant Company
1900 Aston Avenue, Carlsbad, CA 92008. Replace
Select is a trademark of Nobel Biocare. |
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