Background: Depending on the insufficiency of radiographic techniques in investigating changes in grafted sites, this study aimed to evaluate the ability of measuring speed of sound (SOS) as a safe technique for the evaluation of bone graft healing.
Materials and Methods: A total of 20 patients in need of sinus augmentation were recruited for this study. Cone-beam CT scans were obtained presurgically, after 4 months, and after 6 months from surgery per patient. A hydroxyapatite HA and tricalciumphosphate TCP (75:25) grafts were applied for sinus elevation. Speed of Sound (SOS) measurements within the grafted sites were performed in bucco-palatal direction presurgically, directly after surgery, 6 weeks, 3 months, 4 months and 6 months after surgery. At the time of implant placement, bone core biopsies were harvested and sections from the graft core were histomorphometrically analyzed. The new vital bone formation %VB was correlated with SOS measurement outcomes using a statistical model.
Results: Twenty patients underwent sinus augmentation for a total of 20 sinuses. Two sinuses developed an infection after grafting resulting in a 90% success rate for the sinus grafting procedure. An 18 sinuses were used in the final statistical analysis. SOS measurements revealed a mean of 1538.18±28.02 m/s directly after surgery and 1794.21±43.54 m/s after 6 months. Histomorphometric analysis revealed that mean %VB was 20.64±5.36, mean percent of remaining graft material was 23.67±2.99, and average percent of non-mineralized connective tissue was 55.68±4.29. SOS values significantly correlated with %VB (r =0.696, P<0.001). No correlation found between radiographic density of the grafted sites after 6 months and SOS or histomorphometric results.
Conclusions: Measuring sound transmission velocity within the grafted sites is a safe and active technique for the expression of graft content changes and structure and evaluating graft healing.
Keywords: Cone-beam CT, speed of sound, graft, density.DOC-20190406-WA0003