Intracutaneous irritation assessment of a zirconia barrier material (Zirbone) for bone augmentation: rabbit study according to ISO 10993-10:2010 and ISO 10993-12:2021

Abstract

Zirconia barriers have been proposed as an alternative to titanium meshes for guided bone regeneration (GBR) and bone augmentation, but systematic biocompatibility testing is required before clinical use. This study evaluated the intracutaneous irritation potential of a zirconia barrier device (Zirbone) according to ISO 10993‑10. Polar (physiological saline) and non‑polar (cottonseed oil) extracts of Zirbone were prepared in accordance with ISO 10993‑10 and ISO 10993‑12 at an extraction ratio of 3 cm²/mL for 72 ± 2 h at 37 ± 1 °C under gentle agitation. Three young, healthy New Zealand albino rabbits (same sex, ≥ 2 kg) were used. For each animal, 0.2 mL of polar and non‑polar extracts were injected intracutaneously at five sites on one flank, and 0.2 mL of the corresponding extraction media alone were injected at five sites on the contralateral flank. Erythema and edema were scored at 24, 48 and 72 h using standardized scales, and the primary irritation index (PII) was calculated for each extract by comparison with its control solvent. No erythema or edema was observed at any sites injected with the polar solvent or polar Zirbone extract during the 72‑h observation period. In contrast, very slight to well‑defined erythema without edema was observed at sites injected with the non‑polar solvent and non‑polar Zirbone extract at all time points in all animals. The PII was 0.00 for the polar extract and 0.07 for the non‑polar extract, both well below the ISO 10993‑10 acceptance threshold of 1.0 for non‑irritant materials. These findings indicate that polar and non‑polar extracts of the zirconia barrier device Zirbone are non‑irritant according to ISO 10993‑10 and support its local biocompatibility and potential safe use as a barrier material in GBR and bone augmentation procedures.