Soft Tissue Integration of Hydroxyapatite-Coated Abutments for Bone Conduction Implants

Area of Science:

• Biomedical Engineering
• Materials Science
• Otolaryngology

Background:

• Bone conduction hearing implant surgery protocols often require soft tissue reduction around abutments to prevent skin complications.
• Optimizing soft tissue integration is crucial for implant success and patient outcomes.

Purpose of the Study:

• To evaluate the efficacy of hydroxyapatite-coated abutments in enhancing soft tissue integration for bone conduction implants.
• To compare the performance of hydroxyapatite-coated abutments with conventional pure titanium abutments.
• To determine if hydroxyapatite-coated abutments can be used without surgical removal of subepidermal soft tissues.

Main Methods:

• Forty-eight bone conduction implants with either hydroxyapatite-coated (test) or conventional titanium (control) abutments were surgically placed in sheep skulls.
• A 4-week follow-up period was employed.
• Histomorphometric analyses were conducted to assess soft tissue integration and compare the two abutment types.

Main Results:

• Histological examination revealed healthy soft tissues with minimal inflammation around both abutment types.
• Hydroxyapatite-coated abutments demonstrated significantly closer dermal adherence compared to conventional titanium abutments.
• Mean pocket depth was significantly reduced (0.4 mm vs. 1.6 mm) and epidermal downgrowth was significantly less (0.6 mm vs. 2.0 mm) with hydroxyapatite-coated abutments.

Conclusions:

• Hydroxyapatite-coated abutments significantly improve soft tissue integration around bone conduction implants compared to conventional titanium abutments.
• The improved integration is likely due to enhanced adherence at the implant-tissue interface.
• These findings suggest hydroxyapatite-coated abutments are suitable for use without extensive soft tissue reduction procedures.