A COMPARATIVE STUDY BETWEEN THREE GENERIC IMPLANTS |
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- SCOPE
The
scope of the present protocol is to compare:
- The
state-of-the-art manufacture of contact areas between implants
and prosthetic abutments, in order to determine the horizontal
and vertical gap of the components of each one of the implant
systems studied.
- The
reverse torque needed to unscrew the fastening screws of the
abutments.
- Work
hypothesis focuses on the difference of the tapping of the
internal thread of the implants, which would have an influence
on their quality standard.
- FUNDAMENTALS
/ PRECEDENTS
- OsseoMate
II implants are internally threaded by the Single Point system.
With this system, the thread is made using a tool formed by
a shank and a hard-metal insert with the profile of the thread,
digitally controlled by a screw-swiss CNC turning machine.
This process is carried out in the same machine that manufactures
the piece, with no need of a second operation. This process
guarantees a perfect alignment of the internal thread with
the implant axis. The Single Point system cuts the threads
in the internal hole creating the thread M2 x 0.4 and thus
guaranteeing a tolerance of 6H.
- Lot
1 & Lot 2 implant samples are internally threaded by a
different method.
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REFERENCES
- QAP#002Q.
Discovery, Audit, Clearance and Suppliers Control System.
- Production
Order S#058. Threaded-Implant Assembly.
- Metric
Threads (tolerance of M2 x 0.4 – 6H), IRAM 5053 or DIM
13 Standards.
- QAP#040:
Calibration Program.
- QAP#068:
Calibration Standards.
- DOCUMENTATION
Prepare
a final report and include, discuss, or make reference to, the
following (according to what is required):
- Any
deviation from this protocol or abnormalities that might take
place during the comparative study.
-
Copies of calibration records of all instruments associated
with the comparative-study process.
-
Copies of partial records that concern the completion of this
protocol, be them from QA/QC or of external contractors.
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PROCEDURE
- Obtain
5 random samples of each implant brand name.
- Lot
1 Implants
-
Lot 2 Implants
- OsseoMate
II Implants
- Take
each implant out of its original container and inspect visually
the pieces, verifying their condition.
- Write
down Lot number and origin in Appendix I. Work with one Implant
Lot at a time, performing the correspondent production line
set-up.
- Take
a random sample of each Implant Lot, put the implants inside
a sealed plastic bag and label them with their origin, part
number, Lot number, and the legend “INTI”. It will
be sent to INTI, where they will carry out a study on sweep
electronic microscopy in order to see the contact areas between
implants and prosthetic abutments, with the aim of establishing
the horizontal and vertical gap of the components of each
implant system studied. Put the other 4 Lot Implants in a
sealed plastic bag and label them with their origin, part
number, Lot number, and the legend “ENGINEERING”
in order to subject them to dimensional cheking: 1) tolerance
of the internal thread of M2 x 0.4 – 6H, 2) major diameter
of the implant head, 3) tolerance of the fastening screws,
and 4) measure the unscrewing torque as it follows:
- Fix
the implant to the “torque fixture” and then fit
the torque fixture to an adequate torque sensor.
- Begin
by mounting a fastening screw from each Lot on the 0.048 Hex
Driver Tool and place it vertically on the internal thread
of the implant.
-
Make yourself sure that abutments are properly positioned
and screw the fastening screw onto the bottom of the implant,
manually but without tightening.
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Place a torque wrench calibrated to 30 Ncm on the 0.048 Hex
Driver Tool so as to have the arrow directed clockwise when
seen from above. Turn the torque wrench clockwise until the
shank of the torque wrench “breaks”. This will provide
an adjustment force calibrated exactly to 30 Ncm.
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DO NOT OVERTIGHTEN THE SCREWS.
- Then
comes the disassembly, connected to the Norbar torque sensor
so as to obtain the counter-clockwise torque applied through
the record of the maximum value of the unit. These operations
will be repeated 5 (five) times for the same implant, registering
values (I,II,III,IV y V) in the Appendix. The accuracy in
the measurement of the torque is ± 1%, and final measurement
uncertainty will depend on the repeatability of the results.
- The
operations 5.7.1 to 5.7.5 will be repeated for all other implants
registering force values for each case.
- Continue
in the same way with the other 2 Implant Lots registering
the following specifications:
- Torque
for the 3 Implant Lots (4 implants/lot and 5 measurements
per implant)
- Tolerance
checking of M2 x 0.4 – 6H of the implant internal thread
(verifying with go/no go gage).
-
Dimensional checking of the fastening screws for each Lot
(mean diameter and major diameter)
- With
Appendix I results, calculate averages and deviations (statistics)
for each test group.
- Write
a report analyzing the information comparatively and express
there all possible conclusions.
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