A preliminary study of effects of low-intensity pulsed ultrasound (LIPUS) irradiation on dentoalveolar ankylosis.

The purpose of this experiment was to investigate whether low-intensity pulsed ultrasound (LIPUS) irradiation can inhibit dentoalveolar ankylosis in transplanted rat teeth. LIPUS irradiation (the pulsed ultrasound signal had a frequency of 3.0 MHz, a spatial average intensity of 30 mW/cm2, and a pulse ratio of 1:4) was performed on the face over the re-planted teeth of rats for 4 weeks. After the rats were euthanized, we measured mobility (Periotest value [PTV]) of the transplanted and control teeth using a Periotest. Finally, we performed histological evaluation to detect ankylosis. PTVs tended to be significantly lower for re-planted teeth than for control teeth. Histological evaluation revealed that the roots of all re-planted teeth were coalescent with alveolar bone. Furthermore, no ankylosis was observed in three-fifths of the re-planted teeth following LIPUS irradiation. These results indicate the potential efficacy of LIPUS to inhibit dentoalveolar ankylosis.

Functional role of TGF-ß receptors during palatal fusion in vitro.

OBJECTIVE: Reported expression patterns for TGF-ß receptors (TßR-I, -II, and -III) during palatogenesis suggest that they play essential roles in the mechanisms leading to palatal fusion. The purpose of this study was to compare the functions of the three TßRs during palatal fusion. METHODS: Using organ culture of mouse palatal shelves, expression levels of TßR-I, -II, and -III were suppressed by transfecting the siRNAs siTßR-I, -II, and -III, respectively. Phosphorylation of SMAD2 was examined as an indicator of downstream signalling via each TßR. Linkage between TGF-ß signalling and critical events in palatal fusion led to the use of, MMP-13 expression as an outcome measure for the function of the TGF-ß receptors. RESULTS: The siRNA treatment decreased the expression level of each receptor by more than 85%. When treated with either siTßR-I or -II, palatal shelves at E13+72 h were not fused, with complete clefting in the anterior and posterior regions. The middle palatal region following treatment with either siTßR-I or -II had fusion from one-half or one-third of the palatal region. Treatment with siTßR-III resulted in a persistent midline seam of medial edge epithelium (MEE) in the anterior region with islands of persistent MEE in the middle and posterior regions of the midline. Treatment with all three siTßRs altered the pattern of SMAD2 phosphorylation. Palatal shelf cultures treated with siTßR-I or -II, but not -III, showed altered MMP-13 expression levels. CONCLUSION: The ability to identify and recover MEE and palatal mesenchymal cells during palatal fusion will aid in the evaluation of the different mechanistic events regulated by each TßR during palatogenesis.