Hydroxyapatite paste (BoneSource) used as an onlay implant for supraorbital and malar augmentation

Area of Science:

• Biomaterials Science
• Craniofacial Surgery
• Regenerative Medicine

Background:

• Alloplastic materials are used for bone augmentation in craniofacial reconstruction.
• Hydroxyapatite cement offers potential as a biocompatible bone graft substitute.
• Evaluating novel materials like hydroxyapatite paste is crucial for improving surgical outcomes.

Purpose of the Study:

• To assess hydroxyapatite paste as an alloplastic implant for supraorbital and malar augmentation.
• To compare the performance of hydroxyapatite paste with Medpor implants in vivo.
• To evaluate bone ingrowth, biocompatibility, and adverse effects of hydroxyapatite paste implants.

Main Methods:

• Cylindrical hydroxyapatite paste and Medpor implants were placed as onlay grafts in rat supraorbital rims and malar regions.
• Implants were evaluated after 6 months for bone ingrowth, infection, migration, resorption, and tissue response.
• Histological and gross examination were used to assess implant integration and surrounding tissue effects.

Main Results:

• Hydroxyapatite paste implants showed excellent adherence to native bone with evidence of bony ingrowth (approx. 12%).
• No implant migration or gross infection was observed with hydroxyapatite paste.
• While Medpor implants showed some resorption, hydroxyapatite paste implants exhibited minimal resorption, though 20-25% volume loss occurred in some cases.

Conclusions:

• Hydroxyapatite paste is a viable alloplastic material for supraorbital and malar augmentation due to its biocompatibility and adherence.
• The material demonstrated potential for bone regeneration and integration, with fewer adverse effects compared to Medpor.
• Further investigation into the resorptive properties of hydroxyapatite paste is recommended before widespread clinical application.