A pilot evaluation of an aluminum free glass ionomer cement using a sub-chronic osseous defect model in New Zealand white rabbits

Until recently, the development of a clinical-viable aluminum-free glass ionomer cement has been limited by either (i) suitable working times for injection, but inadequate strength for clinical consideration, or conversely, (ii) acceptable strengths with inadequate working characteristics for practical utility. Recent studies, however, point to the inclusion of germanium in these materials as a promising step toward the balancing of clinical handling characteristics with mechanical properties, but no evidence yet exists as to their biocompatibility. In the present study a pilot group of New Zealand White rabbits was implanted with a novel aluminum-free zinc-silicate glass ionomer cement (Zn-Ge GIC) in a subchronic osseous defect model, in order to evaluate the host response to these materials, with a focus on bone healing and remodeling. The Zn-Ge GIC used in this pilot elicited a tissue response characterized by mild and incomplete fibrous encapsulation which did not appear to impair osteoconduction, or osseointegration, characterized by multifocal bone-biomaterial apposition. These data, together with the growing body of literature supporting the clinical utility of Zn-Ge GICs, indicate the significant potential of these materials for hard tissue augmentation.