Adaptation assessment of all-ceramic self-glazed versus conventional zirconia implant abutments

Self-glazed zirconia (SGZ), produced using a novel additive 3D gel deposition technology, has recently been employed to fabricate zirconia abutments. This in vitro study aimed to evaluate the adaptation of one-piece and two-piece all-ceramic SGZ implant abutments in comparison to conventional milled zirconia abutments.

One-piece zirconia abutments and two-piece Ti-base zirconia abutments, sharing an identical 3D design, were fabricated using self-glazed zirconia via 3D gel deposition and conventional zirconia via milling, forming four groups: SGZ-A, SGZ-Ti, Lava-A, and Lava-Ti. Marginal gaps between the zirconia abutments and Ti-base were evaluated using micro-CT data, while gaps between the abutments and implant analogs were assessed on specimen cross-sections by using a stereomicroscope. Statistical analyses were conducted using the non-parametric Mann-Whitney U and Kruskal-Wallis tests with α set at 0.05.

For the two-piece zirconia abutments, the SGZ-Ti group(external gaps:31 ± 20 μm, internal gaps:4 ± 7 μm) exhibited significantly smaller marginal gaps between the zirconia abutment and the Ti-base compared to the Lava-Ti group(external gaps:79 ± 48 μm, internal gaps:51 ± 44 μm) (P<0.001). For the one-piece zirconia abutments, the SGZ-A group(18.5 ± 5.5 μm) demonstrated a significantly smaller gap between the abutment and the implant analog compared to the Lava-A group(26.5 ± 10.0 μm) (P = 0.044). No significant difference was observed among SGZ-A, SGZ-Ti and Lava-Ti groups (P>0.05).

SGZ abutments demonstrate superior adaptation compared to conventional milled zirconia abutments at both the Ti base-abutment interface and the implant-abutment interface. The adaptation of one-piece SGZ abutments is comparable to that of prefabricated Ti-base abutments.