1. Institute of Mechatronic Engineering, Chng Shiu University,
A Comparison of Precision of Fit, Rotational Freedom, and Torque Loss with Copy-Milled Zirconia and Prefabricated Titanium Abutments
Good morning everyone
My name is
The topic of my presentation is A Comparison of Precision of Fit, Rotational Freedom, and Torque Loss with Copy-Milled Zirconia and Prefabricated Titanium Abutments
Chen, Yi-Jung
Institute of Mechatronic Engineering, Chng Shiu University,
Taiwan

2. Outline 1.Introduction 2. Purpose 3. Materials and Methods 4. Results
5. Conclusions
I’ve divided my talk into 5 parts

3. 1. Introduction – False tooth
The first I want introduce false tooth and implant
False tooth have two kind, one is
Fixed prosthodontics the other is Complete denture
Fixed prosthodontics
The Advantages are good for chew , not affect the speech and fall
The Disadvantage is need Grind the teeth on both sides
Complete denture
Advantages are Less power load, you can removed and cleanig
The Disadvantage are Interfere with speech and can not chew
Fixed prosthodontics
Complete denture

4. 1. Introduction – Implant (1/2)
Most of the Advantages about dentures implant have
But its expensive and Treatment time is longer

5. 1. Introduction – Implant (2/2)
The show how to implant
first the implant body put into the gums and then close few month
Screw and abutment are locked into implant , and put the crown

6. 2. Purpose
compare copy-milled zirconia abutments with standard prefabricated
titanium abutments in terms of horizontal and vertical misfit, rotational freedom, and torque loss.

7. 3. Materials and Methods 1. Measurement of concentricity
2. Marginal discrepancy of each abutment within
the implant was measured using the VMM.
3. Measure the rotational misfit between implants
and abutments
4. Loss of applied torque was measured
Twenty regular-platform dental implants with a standard external hexagon of
0.7 mm were used. The implants were randomly divided into two groups. In one group,
prefabricated titanium abutments were used, while in the other group,
custom-made zirconia abutments were fabricated.

8. measurement of concentricity
3. Methods
measurement of concentricity
The first part of the study involved measurement of concentricity,
as well as direct measurement of the internal hexagon and the bearing surfaces of the titanium and zirconia Abutments.
The three-dimensional lateral walls of each hexagon were measured using a video
measuring machine The mean data derived in this manner were then used to determine
whether the titanium and zirconia abutments had comparable measurements.

9. marginal of each abutment within the implant discrepancy
3. Methods
marginal of each abutment within the implant discrepancy
the marginal discrepancy of each abutment within the implant was measured using the VMM.
Implants in each group were embedded in a holder, and zirconia or titanium abutments were secured to the implants by applying 32 Ncm of torque to the abutment screws.
To measure the vertical discrepancy, the sample holder was placed in the VMM so that the implant-abutment interface was positioned horizontally.
A line was traced parallel to the implant platform surface and another was traced to the bottom surface of the abutment.
The distance between the two surfaces was then measured. Then, to determine the horizontal misfit of each specimen, the sample holder was placed in the
VMM so that the implant-abutment interface was positioned vertically.
A vertical line was traced parallel to the outer surface of the implant platform and another was traced to the outer surface of the abutment.
The horizontal distance between these two lines was measured and defined as the horizontal misfit.
The measurements were made at four predetermined reference locations around each abutment,
and the mean values were reported as the horizontal and vertical misfit of each specimen.

10. measure the rotational misfit between implants and abutments
3. Methods
measure the rotational misfit between implants and abutments
to measure the rotational misfit between implants and abutments, the implants were fixed in a holder and the abutments were placed on the corresponding implants; next, a flag was attached to each abutment. Afterward, each abutment was rotated counterclockwise until further rotation was impossible.Subsequently, the abutment was turned clockwise, and the scan was repeated. The angle between the flags in these two pictures was measured as the rotational freedom .

11. loss of applied torque was measured
3. Methods
loss of applied torque was measured
In the fourth part of the study, the loss of applied torque was measured. To determine the torque loss, the implants were positioned in the holding device. Then, each zirconia or titanium abutment was placed by applying 32 Ncm of torque to a new abutment screw using a digital torque wrench , according to the manufacturer’s recommendations. After 5 minutes, the abutment screw was removed, and the torque required to loosen the screw was mea-sured. This procedure was repeated three times for each specimen. The torque loss values were reported as a percentage of the applied torque.

12. 4. Results
The geometric measurements, marginal discrepancies, rotational freedom, and torque loss of both zirconia and titanium abutments are presented in Table 1.
There were statistically significant differences in rotational freedom, horizontal discrepancy, and geometric measurements between the two abutments. The mean percentages of torque loss for the prefabricated titanium and custom-made zirconia abutments were 36.3% ± 4.9% and 44.3% ± 10.3%, respectively.
Although the zirconia abutments showed greater torque loss, the Student test revealed no statistically significant difference between the two groups for this measure.

13. 5.Conclusions
Prefabricated titanium abutments exhibited a mean rotational freedom of 0.99 ± 0.13 degrees, while the zirconia abutments showed a significantly higher mean rotational freedom of 8.28 ± 0.69 degrees.
The average rotation error is 1.21 ± 0.57 degrees.
Present values for the rotational freedom of copy-milled zirconia abutments were greater than 5 degrees, which is considered the acceptable
Several studies have found a direct correlation between rotational freedom and screw loosening at the implant-abutment interface.

14. Thank you