Effects of Low-Intensity Pulsed Ultrasound on Implant Osseointegration in Ovariectomized Rats

Area of Science:

• Biomaterials Science
• Orthopedic Surgery
• Regenerative Medicine

Background:

• Osteoporosis compromises bone quality, increasing the risk of implant failure.
• Osseointegration, the direct structural and functional connection between bone and implant, is crucial for dental and orthopedic implants.
• Low-intensity pulsed ultrasound (US) is a non-invasive therapeutic modality with potential to modulate bone healing.

Purpose of the Study:

• To evaluate the efficacy of low-intensity pulsed ultrasound (US) in enhancing peri-implant bone healing and osseointegration in an established osteoporotic rat model.
• To determine the optimal duration of US treatment for improving bone-implant integration.

Main Methods:

• Ovariectomy was performed on 72 rats to induce osteoporosis, followed by bilateral tibial implant placement.
• One tibia received daily low-intensity pulsed US (40 mW/cm²), while the contralateral tibia served as a control.
• Rats were divided into 6 groups based on US treatment duration (2-12 weeks); outcomes assessed included bone-implant contact, peri-implant bone volume, and implant fixation strength via micro-CT, histology, and removal torque tests.

Main Results:

• Low-intensity pulsed US significantly increased bone-implant contact and peri-implant bone volume at multiple time points compared to controls.
• Removal torque tests demonstrated improved implant fixation strength in the US-treated group from 6 weeks onwards.
• Histological analysis confirmed a favorable bone response to ultrasound stimulation.

Conclusions:

• Low-intensity pulsed ultrasound (US) effectively enhances new bone formation and osseointegration in osteoporotic bone.
• US may serve as a valuable auxiliary treatment to improve implant success rates in patients with compromised bone quality.
• Further research is warranted to fully elucidate the underlying mechanisms of US action in bone regeneration.