Obliteration of the pulp canal caused by mandibular distraction: a case report

We present a 16-year-old boy with a history of ankylosis of the temporomandibular joint (TMJ) who had been treated with a costochondral graft and mandibular distraction. The distraction seems to have caused pulp canal obliteration of the lower right second premolar and lower right first molar on radiographic examination. To our knowledge this is the only reported instance of such damage related to mandibular distraction. We aim to highlight the risks of this complication and the importance of discussing it with patients as part of the process of informed consent.     

The accuracy of virtual-surgical-planning-assisted treatment of hemifacial microsomia in adult patients: distraction osteogenesis vs. orthognathic surgery

Hemifacial microsomia (HFM) is a common congenital craniofacial deformity with a high prevalence. Orthognathic surgery and distraction osteogenesis are two conventionally used treatments of HFM. The main objective of this retrospective study was to evaluate the accuracy of two treatments with the help of virtual surgical planning in adult HFM patients. Sixty-eight adult patients with unilateral HFM were enrolled in this study. Preoperative surgical planning and simulation were performed on three-dimensional computed tomography models. Orthognathic surgery or distraction osteogenesis was performed under the guidance of three-dimensional surgical templates. Postoperative evaluation of the intervention was performed by comparison of the affected ramus height, chin deviation and the occlusal cant in surgical planning and actual result. Outcome and feedback information (an average of 14 months) showed that virtual surgical planning was accurately transferred to actual surgery in both surgical approaches. There were no statistical differences between the accuracy of affected ramus height and the occlusal cant in two surgical approaches. The orthognathic group showed significantly higher accuracy in chin deviation. In conclusion, virtual surgical planning and three-dimensional surgical templates were proved to facilitate treatment planning and offer an accurate surgical result in the treatment of adult HFM patients.     

The effects of dynamic compressive loading on human mesenchymal stem cell osteogenesis in the stiff layer of a bilayer hydrogel

Bilayer hydrogels with a soft cartilage‐like layer and a stiff bone‐like layer embedded with human mesenchymal stem cells (hMSCs) are promising for osteochondral tissue engineering. The goals of this work were to evaluate the effects of dynamic compressive loading (2.5% applied strain, 1 Hz) on osteogenesis in the stiff layer and spatially map local mechanical responses (strain, stress, hydrostatic pressure, and fluid velocity). A bilayer hydrogel was fabricated from soft (24 kPa) and stiff (124 kPa) poly (ethylene glycol) hydrogels. With hMSCs embedded in the stiff layer, osteogenesis was delayed under loading evident by lower OSX and OPN expressions, alkaline phosphatase activity, and collagen content. At Day 28, mineral deposits were present throughout the stiff layer without loading but localized centrally and near the interface under loading. Local strains mapped by particle tracking showed substantial equivalent strain (~1.5%) transferring to the stiff layer. When hMSCs were cultured in stiff single‐layer hydrogels subjected to similar strains, mineralization was inhibited. Finite element analysis revealed that hydrostatic pressures ≥~600 Pa correlated to regions lacking mineralization in both hydrogels. Fluid velocities were low (~1–10 nm/s) in the hydrogels with no apparent correlation to mineralization. Mineralization was recovered by inhibiting ERK1/2, indicating cell‐mediated inhibition. These findings suggest that high strains (~1.5%) combined with higher hydrostatic pressures negatively impact osteogenesis, but in a manner that depends on the magnitude of each mechanical response. This work highlights the importance of local mechanical responses in mediating osteogenesis of hMSCs in bilayer hydrogels being studied for osteochondral tissue engineering.     

从BMSCs探讨“肾主骨生髓”理论指导下中医药治疗骨质疏松症的研究

摘要：骨髓间充质干细胞(bone marrow mesenchymal stem cells, BMSCs)是在一定条件下能够向成骨细胞分化的多能干细胞，其增殖分化与中医“肾主骨生髓”理论及骨质疏松症(osteoporosis, OP)关系密切，大量研究表明传统补肾中药诱导BMSCs增殖分化治疗OP疗效显著。本文以中医“肾主骨生髓”理论为指导，探讨“肾藏精-主骨生髓-BMSCs-OP”之间的科学内涵，并探讨“补肾生髓”理论指导下传统补肾中药通过诱导BMSCs成骨分化与OP的关系，结合补肾中药及复方诱导BMSCs治疗OP的现代医学研究，为进一步探索有效的中医药治疗方案及发挥中医药独特优势提供依据。     

Osteogénesis imperfecta. Descripción de 15 casos

Osteogenesis imperfecta (OI) is an inherited connective tissue disease. The disease has been linked to mutations in one of the type I collagen genes. The diagnosis is based on clinical and radiologic findings. The management of OI in adults is not well-established and includes physical rehabilitation, surgical procedures, the use of antiresorptive therapy and anabolic agents. The aim of the present work was to analyze the clinical and analytical characteristics of these patients in adulthood, as well as to evaluate the different treatments administered. We reviewed the cases of OI diagnosed in our center over the last 12 years (2005-2017). We describe 15 adult patients with OI.