Effect of Pattern Elevation on the Fit of Co-Cr Copings Produced for Implant Abutments

Ahmad Abdel Aziz Mahmoud

Abstract


Objectives: The study's purpose was to evaluate the efficacy of pattern elevation compared to other
methods used for fit manipulation of metal copings produced for implant abutments
Methods: Seventy-seven pattern resin and eleven wax patterns were produced for Friadent 4.5mm
diameter straight abutment and were assigned into eight groups. Four resin groups were elevated from
the abutment for 250μ, 500μ, 750μ and 1000μ respectively in order to produce a die spacer effect, then
were recapped and remargined with resin, one resin group was elevated for 1000μ then was recapped
and remargined with wax, while the other two groups were used without any elevation. The patterns
were invested and cast with Co-Cr alloy. One resin group (no pattern elevation) was invested separately
and followed a different heating cycle prescribed by the manufacturer to produce extra investment
expansion.
After casting, the copings were subjected to sequential fitting rounds. The amount of vertical marginal
gap was measured after each fitting cycle. And the data were analyzed statistically by ANOVA and
Dunnett C Post hoc test.
Results: The 1000 μ-elevated wax recapped and remargined group showed significantly better marginal
fit at the beginning of the fitting process and less time needed to reach target marginal adaption zones.
Compared to the control group (no elevation-pattern resin), only the wax, and 500 μ elevated groups
did also show significantly less fitting time.
Conclusion: Pattern elevation is effective in reducing the fitting time. However, the recapping and
remargining process has a significant influence on effectiveness.

Keywords


Marginal fit, Die spacer, Implant, Pattern resin, Pattern elevation, Crown fit

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