Low-dose rhBMP2/7 heterodimer to reconstruct peri-implant bone defects: a micro-CT evaluation

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Orthopedic Research

Background:

• Peri-implant bone defects pose challenges for dental implant success.
• Bone morphogenetic proteins (BMPs) are crucial for bone regeneration.
• BMP-2 and BMP-7 homodimers have shown efficacy, but heterodimers offer potential advantages.

Purpose of the Study:

• To compare the micro-architectural bone regeneration induced by low-dose BMP-2/7 heterodimer versus BMP-2 and BMP-7 homodimers in peri-implant defects.
• To evaluate the dynamic changes in bone micro-architecture over time.

Main Methods:

• Peri-implant bone defects were surgically created in minipig calvaria around titanium implants.
• Defects were treated with collagen sponges containing low-dose BMP-2/7 heterodimer, BMP-2, or BMP-7.
• Micro-computed tomography and histology were used to assess bone volume, architecture, and bone-implant contact at 2, 3, and 6 weeks.

Main Results:

• BMP-2/7 significantly increased relative bone volume (BV/TV) and improved bone structure (lower SMI) compared to BMP-2 and BMP-7 at 6 weeks.
• Significant differences in trabecular number, thickness, and separation were observed across all time points.
• BMP-2/7 demonstrated higher bone-implant contact (BIC) at 2 weeks.

Conclusions:

• Low-dose BMP-2/7 heterodimer promotes superior and faster bone regeneration in peri-implant defects.
• The findings suggest BMP-2/7 is a promising therapeutic agent for enhancing osseointegration.