Histomorphometry of Longer-Term Implant Interfaces

Objective: The relative stabilities of calcium phosphate (CaP) biomaterial multiphasic coating (plasma sprayed) and particulates (polycrystalline CaP) during bone remodeling were evaluated for longer-term ( >10 year) dental implants. The hypothesis was that the kinetics and mechanisms of osteoclastic interactions would be significantly different. Methods: Three individual post mortem mandibular custom osseous integrated implant devices were processed non decalcified at six transverse locations (18x) to produce multiple (>54) slides. Slides were evaluated by histologic and histomorphometric optical microscopy methods in consultation with a pathologist to select 8 slides for bone-implant interface reactions focused on cells identified by staining. Results: Prior AADR/IADR abstracts and papers have shown conditions of osseous integration, interface biomechanical properties of nano-hardness and -modulus, and microtensile strength. Current analyses show uniquely different interactions where environment and osteoclasts at the bone interface: (1) removes the CaP coating followed by bone deposition along the exposed alloy (Co-Cr-Mo) surfaces with direct bone contact; (2) partially removes (roughens) the surfaces of the polycrystalline CaP particulates with continued osseous integration; and (3) overall opinions from histomorphometric characteristics supporting opportunities for longer-term clinical function. Conclusions: Analyses of bone-implant interfaces and osteoclasts from non decalcified sections of three (>10 year) post mortem custom dental implants showed very different interactions where CaP coatings were being replaced, particulate CaP were partially replaced, and osseous integration and clinical function were maintained. IRB #X050823001 CMBD Core NIH P30-AR403 Special recognition: D. Martin, DMD and Donors