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Internal fit of cobalt-chromium and zirconia implant abutments fabricated using different techniques: a
Pedro Molinero-Mourelle1,2,3, Seyed Ali Mosaddad1,4, Rocio Cascos-Sanchez1
1Department of Conservative Dentistry and Prosthodontics, Faculty of Dentistry, Complutense University of Madrid, Madrid, Spain.
Purpose:
To evaluate the internal fit at the implant-abutment interface of zirconia and cobalt-chromium abutments fabricated using different techniques by micro-computed tomography (micro-CT).
Methods:
Twenty screw-retained abutments were divided into 4 groups (n = 5): milled zirconia (ZrCAD), milled cobalt-chromium (Co-CrMill), laser-sintered cobalt-chromium (Co-CrLS), and cast cobalt-chromium (Co-CrCL). Specimens were subjected to cyclic loading (300,000 cycles, 200 N) and thermocycling (10000 cycles, 5 to 50 °C). Internal fit was assessed by micro-CT at 3 regions and 3 spatial planes (180 measurements). Data were analyzed with Kruskal-Wallis and Bonferroni-Holm tests (α = 0.05).
Results:
Significant differences in internal fit were found (p < 0.05). Co-CrLS showed the highest internal gap values (26.75 ± 7.05 μm, 87.00 ± 3.26 μm, 86.50 ± 5.76 μm). Significant differences were observed between Co-CrLS and ZrCAD (Region 1, p = 0.003), Co-CrMill (Regions 1 and 2, p = 0.003-0.004), and Co-CrCL (Regions 1 and 3, p = 0.003-0.001). Total values also differed between Co-CrMill and Co-CrLS (p = 0.012) and Co-CrCL and Co-CrLS (p = 0.002).
Conclusions:
Internal fit differed among the evaluated workflows. Laser-sintered cobalt-chromium abutments showed the least favorable adaptation, whereas milled and cast cobalt-chromium showed lower gap values; zirconia showed intermediate descriptive values. The clinical significance of these differences remains uncertain.
Clinical Trial Number:
Not applicable.
