In vitro evaluation of wear characteristics in complete arch implant-supported fixed dental prostheses: Impact of...

Wear of complete arch implant-supported fixed dental prostheses (ISFDPs) arises from interactions between framework and veneering materials under cyclic loading. However, the combined influence of these pairings on volumetric and vertical wear remains unclear.

The purpose of this in vitro study was to compare volumetric wear (ΔV) and vertical height loss (ΔH) among 6 mandibular ISFDP framework-veneer combinations and to assess within-group ΔV-ΔH correlations.

Forty-two mandibular complete arch ISFDPs (6 groups; n=7) were opposed by identical complete contour monolithic zirconia antagonists and subjected to 1 250 000 mastication cycles (80 N, 1.2 Hz, 2.0 mm vertical, 1.0 mm lateral) with thermocycling (5 to 55 °C). ΔV was quantified from pre- and posttest structured-light scans; ΔH was recorded continuously by inductive sensors. Data were analyzed with Kruskal-Wallis and Dunn (Bonferroni) tests and Spearman correlation (α=.05).

ΔV differed among groups (P<.001): medians (mm³) were PEKK-Comp 0.205, PEKK-e.max 0.405, PEEK-e.max 0.875, ZIR-e.max 1.016, PEEK-Comp 1.025, Co-Cr-Comp 1.580; PEKK-based lowest, Co-Cr-Comp highest. ΔH also differed (P<.001): medians (mm) were PEKK-Comp 0.28, PEEK-Comp 0.33, ZIR-e.max 0.38, PEKK-e.max 0.49, PEEK-e.max 0.62, Co-Cr-Comp 0.64. A strong positive ΔV-ΔH correlation occurred only in PEKK-e.max (ρ=.893, P=.007). No veneer chipping occurred during 1 250 000 cycles.

Volumetric wear was primarily influenced by framework composition and vertical wear by veneering material. PEKK-based ISFDPs exhibited the least wear, whereas cobalt chromium-composite resin combinations showed the greatest. Composite resin veneers on polymer frameworks and lithium-disilicate veneers on zirconia preserved vertical dimension better. The PEKK-lithium disilicate pairing demonstrated a consistent, predictable wear trajectory.