Local application of Usag-1 siRNA can promote tooth regeneration in Runx2-deficient mice.

Runt-related transcription factor 2 (Runx2)-deficient mice can be used to model congenital tooth agenesis in humans. Conversely, uterine sensitization-associated gene-1 (Usag-1)-deficient mice exhibit supernumerary tooth formation. Arrested tooth formation can be restored by crossing both knockout-mouse strains; however, it remains unclear whether topical inhibition of Usag-1 expression can enable the recovery of tooth formation in Runx2-deficient mice. Here, we tested whether inhibiting the topical expression of Usag-1 can reverse arrested tooth formation after Runx2 abrogation. The results showed that local application of Usag-1 Stealth small interfering RNA (siRNA) promoted tooth development following Runx2 siRNA-induced agenesis. Additionally, renal capsule transplantation of siRNA-loaded cationized, gelatin-treated mouse mandibles confirmed that cationized gelatin can serve as an effective drug-delivery system. We then performed renal capsule transplantation of wild-type and Runx2-knockout (KO) mouse mandibles, treated with Usag-1 siRNA, revealing that hindered tooth formation was rescued by Usag-1 knockdown. Furthermore, topically applied Usag-1 siRNA partially rescued arrested tooth development in Runx2-KO mice, demonstrating its potential for regenerating teeth in Runx2-deficient mice. Our findings have implications for developing topical treatments for congenital tooth agenesis.

Loss of Stemness, EMT, and Supernumerary Tooth Formation in Cebpb-/-Runx2+/- Murine Incisors.

Adult Cebpb KO mice incisors present amelogenin-positive epithelium pearls, enamel and dentin allopathic hyperplasia, fewer Sox2-positive cells in labial cervical loop epitheliums, and reduced Sox2 expression in enamel epithelial stem cells. Thus, Cebpb acts upstream of Sox2 to regulate stemness. In this study, Cebpb KO mice demonstrated cementum-like hard tissue in dental pulp, loss of polarity by ameloblasts, enamel matrix in ameloblastic layer, and increased expression of epithelial-mesenchymal transition (EMT) markers in a Cebpb knockdown mouse enamel epithelial stem cell line. Runx2 knockdown in the cell line presented a similar expression pattern. Therefore, the EMT enabled disengaged odontogenic epithelial stem cells to develop supernumerary teeth. Cebpb and Runx2 knockdown in the cell line revealed higher Biglycan and Decorin expression, and Decorin-positive staining in the periapical region, indicating their involvement in supernumerary tooth formation. Cebpb and Runx2 acted synergistically and played an important role in the formation of supernumerary teeth in adult incisors.

Maxillary Hypoplasia With Congenital Oligodontia Treated by Maxillary Distraction Osteogenesis.

It is known that congenitally missing teeth can often cause differences in craniofacial morphology; however, there are few reported cases of orthognathic surgical treatment for these patients. Herein, the authors report a rare case of maxillary hypoplasia with congenital oligodontia treated by maxillary distraction osteogenesis with internal device. A 17-year-old male presenting with multiple tooth agenesis and maxillary recession was referred to our hospital for orthognathic surgical treatment. Preoperative simulation surgery was performed using Full-Color 3-dimensional salt model. After surgery, improvement in maxillary recession and occlusal stability was observed. This report demonstrates the advantages of the method used herein, which includes reduction in operating time with increase in the safety of the procedure.

The Relationship Between Cephalogram Analysis and Oxygen Desaturation Index During Sleep in Patients Submitted for Mandibular Setback Surgery.

OBJECTIVES: The aim of this study was to examine the relationship between morphologic factors of mandibular protrusion patients and clinical indices of obstructive sleep apnea (OSA). METHODS: Fifty-two Japanese patients divided into 2 groups: 1 jaw surgery group (30 patients) and 2 jaw surgery group (22 patients). Morphologic changes were studied using cephalograms taken before surgery and 1 year after surgery. Functional changes studied using impulse oscillometry and pulse oximetry during sleep, both of which are clinically useful measures in assessing OSA, taken before surgery and 1 year after surgery. RESULT: Lower face cage area significantly decreased in 1 jaw group than in 2 jaw group patients. Positive significant correlation was found between changes in 3% oxygen desaturation index (ODI) and changes of tongue area and vertical position of the hyoid bone in 1 jaw surgery group. Multiple regression analysis indicates that tongue area and airway area were independently significant predictors of 3% ODI in 1 jaw group patients. CONCLUSION: In 2 jaw surgery, maxillary surgery compensated for the effect of mandibular setback surgery. Mandibular setback surgery to mandibular protrusion patients was performed within the range of adequate movement distance, but precautions for risk of postoperative obstructive sleep apnea syndrome should be considered.