J Adv Prosthodont.  2014 Feb;6(1):46-52. 10.4047/jap.2014.6.1.46.

A comparative study of gold UCLA-type and CAD/CAM titanium implant abutments

• Park JM
• Lee JB
• Heo SJ
• Park EJ

• KMID: 2176570
• DOI: http://doi.org/10.4047/jap.2014.6.1.46

Abstract

PURPOSE
The aim of this study was to evaluate the interface accuracy of computer-assisted designed and manufactured (CAD/CAM) titanium abutments and implant fixture compared to gold-cast UCLA abutments.
MATERIALS AND METHODS
An external connection implant system (Mark III, n=10) and an internal connection implant system (Replace Select, n=10) were used, 5 of each group were connected to milled titanium abutment and the rest were connected to the gold-cast UCLA abutments. The implant fixture and abutment were tightened to torque of 35 Ncm using a digital torque gauge, and initial detorque values were measured 10 minutes after tightening. To mimic the mastication, a cyclic loading was applied at 14 Hz for one million cycles, with the stress amplitude range being within 0 N to 100 N. After the cyclic loading, detorque values were measured again. The fixture-abutment gaps were measured under a microscope and recorded with an accuracy of +/-0.1 microm at 50 points.
RESULTS
Initial detorque values of milled abutment were significantly higher than those of cast abutment (P<.05). Detorque values after one million dynamic cyclic loadings were not significantly different (P>.05). After cyclic loading, detorque values of cast abutment increased, but those of milled abutment decreased (P<.05). There was no significant difference of gap dimension between the milled abutment group and the cast abutment group after cyclic loading.
CONCLUSION
In conclusion, CAD/CAM milled titanium abutment can be fabricated with sufficient accuracy to permit screw joint stability between abutment and fixture comparable to that of the traditional gold cast UCLA abutment.

Keyword

Gold-cast UCLA abutments; CAD/CAM titanium abutments; Cyclic loading; Detorque value; Fixture-abutment gap

MeSH Terms

Computer-Aided Design
Joints
Mastication
Titanium*
Torque
Titanium

Figure

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  Fig. 1 Schematic diagram of custom crown design.

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  Fig. 2 Detorque values measured by a digital torque gauge.

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  Fig. 3 Cyclic loading application (Mini Bionix II Test System and mounted implant-abutment-crown complex).

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  Fig. 4 Fixture-abutment gap measurement.

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  Fig. 5 Detorque values before and after 106 cycles of loading.

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  Fig. 6 Fixture-abutment gap discrepancy.

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  Fig. 7 Fixture-abutment gap discrepancy shown under light microscope of Acura 2000 system (×240). There was no major morphologic aberration at the fixture-abutment gap in all groups. A: External/UCLA, B: External/CADCAM, C: Internal/UCLA, D: Internal/CADCAM.

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