Enhanced bone healing around nanohydroxyapatite-coated polyetheretherketone implants: An experimental study in rabbit...

Bone integration of implants remains a central challenge in orthopedic and dental applications. While titanium is widely used, alternatives like polyetheretherketone (PEEK) offer biocompatibility and mechanical advantages. However, PEEK lacks the osteoconductive properties of metallic implants. Previous studies have explored surface modifications to enhance PEEK’s bone response. Coatings such as hydroxyapatite have been proposed to improve osseointegration. Yet, the effect of nanohydroxyapatite on PEEK implants has not been fully evaluated. This uncertainty motivated the current investigation. Researchers aimed to assess whether nanohydroxyapatite coatings could improve bone healing around PEEK implants. The study focused on threaded designs, which are commonly used in clinical settings.

The study aimed to evaluate the bone-healing response to nanohydroxyapatite-coated PEEK implants compared to uncoated controls. Researchers wanted to determine if the coating could enhance osseointegration in a rabbit model. The threaded design of the implants was selected to mimic clinical applications. The primary outcome was bone-to-implant contact, a key indicator of integration. Secondary outcomes included removal torque and bone area. The study also assessed inflammatory responses to the implants. Researchers hypothesized that the coating would improve bone formation. The rabbit tibia and femur were chosen for their relevance to human bone healing.

Researchers prepared 39 coated and 39 uncoated PEEK implants. Surface characteristics were analyzed using optical interferometry and scanning electron microscopy. The implants were surgically placed in the tibia and femur of 13 rabbits. Animals were monitored for six weeks to allow bone healing. After retrieval, removal torque tests measured implant stability. Histomorphometric analysis quantified bone-to-implant contact and bone area. Histological evaluation assessed inflammatory cell infiltration. Researchers compared outcomes between the two groups using statistical tests. The study design ensured a controlled comparison of coated and uncoated implants.

Test implants showed significantly higher removal torque values than controls. Histomorphometric analysis revealed greater bone-to-implant contact in the test group. However, bone area did not differ between the two groups. Both implant types showed similar inflammatory cell infiltration. Foreign body giant cells were observed in two-cell layers around both surfaces. The threaded design contributed to stability in both groups. Coated implants demonstrated improved bone formation compared to uncoated ones. The coating did not eliminate inflammatory responses but enhanced osseointegration.

The study shows that nanohydroxyapatite coatings improve bone formation around PEEK implants. Coated implants had higher removal torque and bone-to-implant contact than controls. The threaded design provided sufficient stability in both groups. Inflammatory responses were similar for both implant types. The coating did not increase bone area but enhanced integration. Researchers suggest that the coating may be beneficial for PEEK implants. The findings support the use of nanohydroxyapatite in improving osseointegration. Further studies are needed to confirm clinical applicability.