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

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