Effect of Ultrasound on Healing of Dentoalveolar Fracture ex-vivo

Objective: To examine the effect of low intensity pulsed ultrasound (LIPUS) on a fractured dentoalveolar structure in an ex-vivo rat mandible organ culture with or without dentine matrix protein (DMP).

Method: Mandibles were dissected from eight 28-day-old male Sprague Dawley rats and sectioned into 1.5mm transverse slices. A standardized fracture in the alveolar bone was performed in all slices and they were divided into 5 groups: control, 5min LIPUS 10min LIPUS, 0.001mgg/ml DMP and 10min DMP plus LIPUS. Mandible slices were incubated for 7 days then they were processed for histological examination. Analysis of the results was made using quantitative histomorphometric analysis using Metamorph software, which involved calculating the cell densities in the various cell layers (bone, dentine and periodontal ligament fracture and healing areas).

Result: One-Way ANOVA with a Bonferroni Post Hoc test revealed a significant increase in cell density in all layers of 5min, 10min LIPUS groups when compared with control group. There was a significant decrease in cell density in layers in DMP group with no significant difference in cell density in all layers between 5min & 10min ultrasound (P>0.05).However, there was a significant increase in cell density in DMP+LIPUS in compare to control DMP.

Conclusion: Our results suggest that application of LIPUS to a dentoalveolar fracture in an ex-vivo culture system may enhance healing by increasing the cell density in the periodontal ligament and alveolar bone especially when combined with DMP.