(35) Ultrasonographic Wound Healing Evaluation of Guided Bone Regeneration with Non-Resorbable Membranes

Introduction: Guided bone regeneration (GBR) via the use of a non-resorbable membrane is indicated for reconstructing severe ridge defects before implant rehabilitation. Real-time, non-invasive, and high-image-resolution ultrasonography might be a clinical solution for objectively monitoring wound healing after GBR procedures.

Methods: In this case-series study, wound healing of five patients undergoing GBR using a non-resorbable membrane were evaluated with high-resolution dental ultrasound. B-mode and Color/Power ultrasound images were taken at the baseline and subsequent follow-up visits. Images on the occlusal, facial, and lingual sites were acquired. Soft and hard tissue dimension and blood flow changes were measured and compared within the sites and between sites with and without healing complications, i.e., soft tissue dehiscence resulting in membrane exposure.

Results: On B-mode images, the non-resorbable, membrane is shown as a hyperechoic line. Underneath the membrane the jawbone surface might not be seen during early healing period because of sound attenuation at the membrane surface. Jawbone surface could be seen after a couple months after the healing, possibly due to gradual degradation of the membrane. One case experienced an uneventful healing process, whereas the other had a compromised healing accompanied with infection. The peri-membrane space (mm) between the membrane and the jawbone surface is wider and has lower pixel density in the eventful cases. Ultrasound color pixel fraction (CPF) (%), indicative of tissue perfusion, increased significantly at 2 weeks compared to the baseline, peaked at 1 months, and returned to the baseline at 6 months. CPF is significantly higher in the eventful cases than in the uneventful case. Ultrasound jawbone width decreases across the healing period, suggesting consolidation of bone grafting materials.

Conclusions: Ultrasound-derived parameters, e.g., peri-membrane space and pixel intensity, color pixel fraction, and tissue dimension changes could be useful for making clinical decisions during GBR wound healing. With validation, high-resolution dental ultrasound can monitor and evaluate GBR wound healing at chairside and non-invasively for a personalized and timely approach.
Keywords: guided bone regeneration, Ultrasonography, Ultrasound Scan, Soft tissue, Dental Implants

Lead Author's Contributions to the Research Project. : The lead author was responsible for the acquisition of the ultrasound scans from the included subjects, analysis and perception of the taken images. Finally, data analysis and writing the manuscript.