Intermittent PTH administration improves alveolar bone formation in type 1 diabetic rats with periodontitis.

BACKGROUND: Periodontitis is an infectious disease that manifests as alveolar bone loss surrounding the roots of teeth. Diabetes aggravates periodontitis-induced alveolar bone loss via suppression of bone formation. Intermittent parathyroid hormone (PTH) administration displays an anabolic effect on bone. In this study, we investigated the effect of intermittent PTH administration on alveolar bone loss in type 1 diabetic rats with periodontitis. METHODS: Rats were divided into control (C), periodontitis (P), periodontitis treated with PTH (P + PTH), diabetes with periodontitis (DP), and diabetes with periodontitis treated with PTH (DP + PTH) groups. To induce type 1 diabetes, rats were injected with streptozotocin and periodontitis was induced bilaterally by applying ligatures to the mandibular first molars for 30 days. During the experimental period, the P + PTH and DP + PTH groups were subcutaneously injected with PTH (40 µg/kg) three times per week, whereas the C, P, and DP groups were injected with citrate buffer. To observe the mineralization of the alveolar bone, the DP and DP + PTH groups were injected with calcein on days 10 and 27, and with alizarin red on day 20. Thirty days after ligation, histological findings and fluorescence labeling were analyzed in the furcations of the mandibular first molars. Sclerostin-positive osteocytes were assessed by immunohistochemical analyses. RESULTS: The DP groups had smaller areas of alveolar bone than the other groups, and the DP + PTH group had a larger alveolar bone area than the DP group. The DP group had less osteoid formation than the C group, whereas the DP + PTH had greater osteoid formation than the DP group. Fluorescence labeling results revealed that the DP + PTH group had more mineral deposition on the alveolar bone than the DP group. The DP + PTH group exhibited lower percentage of sclerostin-positive osteocytes in alveolar bone than the DP group. CONCLUSIONS: Intermittent PTH administration diminishes alveolar bone loss and sclerostin expression in osteocytes, but increases osteoid formation and mineralization, suggesting that intermittent PTH administration attenuates diabetes-aggravated alveolar bone loss by the induction of bone formation. PTH-induced bone formation may be related to the regulation of osteocytic sclerostin expression in type 1 diabetic rats with periodontitis.

Clinical outcomes of gingivoperiosteoplasty for unilateral cleft lip and palate performed in early childhood.

Conventional gingivoperiosteoplasty (GPP) performed during infancy adversely affects maxillary development. However, the outcomes of this procedure in early childhood have rarely been reported. Therefore, we examined the postoperative outcomes of GPP conducted in patients aged 1.5 years with unilateral cleft lip and palate (UCLP). This study included 87 non-syndromic patients with complete UCLP who had undergone early two-stage palatoplasty during the 1999-2004 period. The protocol comprised soft palate plasty at 1 year of age and hard palate closure at 1.5 years of age. In the GPP group (n = 34), we introduced the GPP procedure during hard palate closure; in the non-GPP group (n = 53), the labial side of the alveolar cleft remained intact. We examined computed tomography images taken at 8 years of age to observe bone formation at the alveolar cleft site. We also conducted cephalometric analysis to examine maxillary development at 12 years of age. Bone bridges at the alveolar cleft site were observed in 92% and 5.6% of the GPP and non-GPP groups, respectively. Moreover, 56% of the GPP group did not require secondary alveolar bone grafting (sABG), whereas all the patients in the non-GPP group underwent sABG. No statistically significant differences were noted in the maxillary anteroposterior length (GPP: 45.5 ± 3.7 mm, non-GPP: 45.9 ± 3.5 mm, p = 0.67) and sella-nasion-point A angle (GPP: 75.6 ± 4.5°, non-GPP: 73.8 ± 12.6°, p = 0.49). This study's findings suggest that GPP performed at 1.5 years of age minimises the necessity of sABG and does not exert a negative influence on maxillofacial development.

Plasmid encoding miRNA-200c delivered by CaCO3-based nanoparticles enhances rat alveolar bone formation.

Aim: miRNAs have been shown to improve the restoration of craniofacial bone defects. This work aimed to enhance transfection efficiency and miR-200c-induced bone formation in alveolar bone defects via plasmid DNA encoding miR-200c delivery from CaCO3 nanoparticles. Materials & methods: The CaCO3/miR-200c delivery system was evaluated in vitro (microscopy, transfection efficiency, biocompatibility) and miR-200c-induced in vivo alveolar bone formation was assessed via micro-computed tomography and histology. Results: CaCO3 nanoparticles significantly enhanced the transfection of plasmid DNA encoding miR-200c without inflammatory effects and sustained miR-200c expression. CaCO3/miR-200c treatment in vivo significantly increased bone formation in rat alveolar bone defects. Conclusion: CaCO3 nanoparticles enhance miR-200c delivery to accelerate alveolar bone formation, thereby demonstrating the application of CaCO3/miR-200c to craniofacial bone defects.

The restoration of craniofacial bone defects is surgically complex and requires the combined use of bone grafts and regenerative biomaterials. miRNAs are small biomolecules that have been shown to improve bone regeneration in large bone defects. The aim of this work was to develop a nanoparticle-based delivery system to sustain the release of miRNAs to improve the restoration of craniofacial bone defects. The results of this study demonstrated that CaCO₃ nanoparticles extend the delivery of miRNAs to enhance bone formation in a craniofacial bone defect animal model in a therapeutically safe manner that improves upon conventional nanoparticle materials for bone regeneration. The findings attest to the regenerative properties of miRNAs and further indicate the potential application of CaCO₃-based nanoparticles in restoring large bone defects.

Silk Fibroin/Collagen/Hydroxyapatite Scaffolds Obtained by 3D Printing Technology and Loaded with Recombinant Human Erythropoietin in the Reconstruction of Alveolar Bone Defects.

The fast osteogenesis of the large alveolar fossa and the maintenance of the height of the alveolar ridge after tooth extraction have always been a clinical challenge. Therefore, this work describes the creation of innovative silk fibroin/collagen/hydroxyapatite (SCH) biological scaffolds by 3D printing technology, which are loaded with recombinant human erythropoietin (rh-EPO) for the reconstruction of bone defects. Low-temperature 3D printing can maintain the biological activity of silk fibroin and collagen. The SCH scaffolds showed the ideal water absorption and porosity, being a sustained-release carrier of rh-EPO. The optimized scaffolds had ideal mechanical properties in vitro, and MC3T3-E1 cells could easily adhere and proliferate on it. In vivo experiments in rabbits demonstrated that the composite scaffolds gradually degraded and promoted the accumulation and proliferation of osteoblasts and the formation of collagen fibers, significantly promoting the reconstruction of mandibular defects. In this study, a novel composite biological scaffold was prepared using 3D printing technology, and the scaffold was innovatively combined with the multifunctional growth factor rh-EPO. This provides a new optimized composite material for the reconstruction of irregular mandible defects, and this biomaterial is promising for clinical reconstruction of alveolar bone defects.

High-Frequency, Low-Intensity Pulsed Ultrasound Enhances Alveolar Bone Healing of Extraction Sockets in Rats: A Pilot Study.

Most studies of the beneficial effects of low-intensity pulsed ultrasound (LIPUS) on bone healing have used frequencies between 1.0 and 1.5 MHz. However, after consideration of ultrasound wave characteristics and depth of target tissue, higher-frequency LIPUS may have been more effective on superficially positioned alveolar bone. We investigated this hypothesis by applying LIPUS (frequency, 3.0 MHz; intensity, 30 mW/cm(2)) on shaved right cheeks over alveolar bones of tooth extraction sockets in rats for 10 min/d for 2 wk after tooth extraction; the control group (left cheek of the same rats) did not receive LIPUS treatment. Compared with the control group, the LIPUS group manifested more new bone growth inside the sockets on histomorphometric analysis (maximal difference = 2.5-fold on the seventh day after extraction) and higher expressions of osteogenesis-related mRNAs and proteins than the control group did. These findings indicate that 3.0-MHz LIPUS could enhance alveolar bone formation and calcification in rats.