Effects of Implanting Torques on Implant Osseointegration in an Animal Model

Objective: To investigate the effect of insertion torque on implant osseointegration in an animal model. Methods: First, the first to fourth premolars of nine healthy adult beagles’ mandibular were extracted to form an edentulous area, and then the beagles were equally divided into three groups with different torques (low torque: 10–30 Ncm; medium torque: 30–50 Ncm; high torque: > 70 Ncm). Three implants were placed on each side of the edentulous area of the beagles (54 total), and the dogs were observed for 8 weeks. Implant performance and removal torque values (RTV) were determined at 1, 4, and 8 weeks after surgery. In addition, the expression ratios of OPG and RANKL mRNAs in the surrounding bone tissue were determined. Results: None of the 54 implants showed loosening or loss, and no significant bone resorption was observed. The removing torques and the expression ratios of OPG and RANKL mRNAs showed differences at 1 and 4 weeks after surgery, while they converged at 8 weeks after the surgery (p > 0.05). Conclusion: The osteointegration process lasted approximately 8 weeks depending on the difference in parameters, and all parameters showed the same values even though the insertion torques at the beginning were different.

Ionizing Radiation Activates Mitochondrial Function in Osteoclasts and Causes Bone Loss in Young Adult Male Mice

The damaging effects of ionizing radiation (IR) on bone mass are well-documented in mice and humans and are most likely due to increased osteoclast number and function. However, the mechanisms leading to inappropriate increases in osteoclastic bone resorption are only partially understood. Here, we show that exposure to multiple fractions of low-doses (10 fractions of 0.4 Gy total body irradiation [TBI]/week, i.e., fractionated exposure) and/or a single exposure to the same total dose of 4 Gy TBI causes a decrease in trabecular, but not cortical, bone mass in young adult male mice. This damaging effect was associated with highly activated bone resorption. Both osteoclast differentiation and maturation increased in cultures of bone marrow-derived macrophages from mice exposed to either fractionated or singular TBI. IR also increased the expression and enzymatic activity of mitochondrial deacetylase Sirtuin-3 (Sirt3)—an essential protein for osteoclast mitochondrial activity and bone resorption in the development of osteoporosis. Osteoclast progenitors lacking Sirt3 exposed to IR exhibited impaired resorptive activity. Taken together, targeting impairment of osteoclast mitochondrial activity could be a novel therapeutic strategy for IR-induced bone loss, and Sirt3 is likely a major mediator of this effect.

Case Report: Prophylactic Plate Fixation for Incomplete Atypical Ulnar Fractures Resulting From the Use of Denosumab for Bone Metastases

Patients with bone metastases are treated with long-term bone resorption inhibitors such as bisphosphonates and denosumab. However, resorption inhibitors have been known to cause fractures, such as atypical femoral fractures (AFFs). In recent years, there have been an increasing number of reports of atypical ulna fractures (AUFs) caused by bone resorption inhibitor usage. Treatment of AUFs is complicated, especially when they occur in patients with bone metastases, because it is difficult to discontinue bone resorption inhibitor treatment without the risk of aggravating metastatic lesions. Prophylactic surgery is recommended in AFFs when fractures are predicted, but there are few reports of prophylactic surgery for AUFs. Here, we report a case of incomplete AUF in a 74-year-old woman which was surgically treated with prophylactic plate fixation. The patient had been using denosumab for 6 years to treat bone metastases due to thyroid cancer. After surgery, no fractures were observed for 2 years without discontinuing denosumab, and her forearm function was adequate. AUFs are rare and difficult to treat, so oncologists who treat bone metastases need to pay special attention to diagnose this incomplete AUF before the fracture worsens. We believe that detection of a possible fracture and prophylactic surgery can improve prognosis.

Band acro-osteolysis in a black female: a case report and review of literature

Acro-osteolysis is a bone resorption reaction that progresses slowly in the distal phalanx of the hand and foot and is associated with various diseases. It can be classified as idiopathic or secondary. Although the mechanism of acro-osteolysis has not been fully elucidated, the chronic ischemic injury appears to have a significant effect, and bone metabolism dysregulation due to the accompanying calcinosis or peripheral neuropathy also appears to contribute. Acro-osteolysis can show various clinical and radiological features, and differential diagnosis of the underlying etiology is essential. It is a rare sporadic disease worldwide, and the authors experienced a patient with acro-osteolysis suspected of idiopathic cause in a black woman, so we report this case with literature reviews.

Immunohistochemical features of the bone tissue of the lower extremities in patients with type 2 diabetes mellitus

Background: Diabetic neuroosteoarthropathy is a serious disabling complication of diabetes mellitus, which, in the absence of timely correct treatment, can lead to high amputations of the affected limb. At present, the reasons and mechanism of the development of Charcot’s foot are not completely clear. It is extremely important to determine the pathophysiological mechanisms of DNOAP formation and to search for reliable markers-predictors of this pathology.Aim: To study the immunohistochemical characteristics of the bone tissue of the lower extremities in patients with diabetic neuroosteoarthropathy in comparison with patients with diabetes mellitus without this pathology.Materials and methods: During the foot surgery, a bone fragment of the foot was harvested for immunohistochemical study of receptor markers for PINP, PIIINP, and RAGE in the group of patients with DNOAP compared with the control group.Results: The study included 20 patients with type 2 diabetes mellitus and were divided into 2 groups: 10 patients with DNOAP made up group 1, 10 patients without DNOAP — group 2.Patients in both groups were comparable in AGE, experience with type 2 diabetes, and glycemic control.During the immunohistochemical study, a significant increase in the staining intensity of receptor markers for PINP, PIIINP, and AGE was recorded in the group of patients with DNOAP compared with the control group (p <0.05).Conclusion: For the first time, an immunohistochemical study of markers of bone resorption and AGE was carried out in persons with DNOAP. The results obtained indicate impaired collagen formation and, as a consequence, impaired bone formation and bone resorption in patients with DNOAP: in group 1, a statistically significant increase in the expression of PINP, PIIINP, and RAGE was revealed.

EGFL6 Promotes Bone Metastasis of Lung Adenocarcinoma by Enhancing Osteoclast Differentiation and Stimulating Cancer Cell Metastasis

Background Lung cancer is still the most fatal cancer today with approximately 30%-40% of these patients will develop bone metastasis. Lung adenocarcinoma (LUAD) is the most common and aggressive type of lung cancer. The relationship between LUAD and bone metastasis and its underlying mechanism remains unclear. This study proved that epidermal growth factor-like domain multiple 6 (EGFL6) was highly expressed in LUAD specimens of patients, and the expression level was positively correlated with bone metastasis of LUAD. Method The expression of EGFL6 in cancer tissues was detected by IHC. CCK-8, colony formation assay, migration and invasion assay, wound healing assay, immunocytochemistry, RT-PCR, Western blotting, ELISA, bone resorption, TRAP staining and H&E staining were performed. A nude mouse model of LUAD-induced bone destruction was established by injecting A549 cells in different EGFL6 expression levels. Results EGFL6 is elevated in LUAD and is associated with bone metastasis. In vivo, implantation of human adenocarcinoma A549 cells with a higher expression of EGFL6 not only increased tumor growth rate but also bone resorption of tibias in nude mice. In vitro, the secretion of EGFL6 from A549 cells increased osteoclast differentiation but had little effect on osteogenic differentiation. To reveal the underlying mechanism, we demonstrated that EGFL6 enhanced osteoclast differentiation through activating nuclear factor-kappa B (NF-κB) and downstream c-Fos/NFATc1 signaling pathways, and in addition promoted the proliferation, migration and invasion of A549 cells through enhancing the epithelial mesenchymal transformation (EMT) and promoting Wnt/β-catenin and PI3K/AKT/mTOR signaling pathways. Conclusions We unveil EGFL6 as a predictor in bone metastasis of LUAD and underscore the relevance of EGFL6 as a therapeutic target.

Cerium oxide nanozyme attenuates periodontal bone destruction by inhibiting ROS-NFκB pathway

Periodontitis, an inflammatory disease of oxidative stress, occurs due to the excess reactive oxygen species (ROS) contributing to cell and tissue damage that in turn leads to alveolar bone resorption...

Analysis of osteoblast, osteoclast levels and radiographic patterns in the healing process of bone fractures (preliminary research)

Objectives: The healing process of a bone fracture goes through many phases. The hard callus phase was critical where the original structure was conducted. The hard callus growth depends on osteoblasts and osteoclasts active, and this condition can be analyzed on the radiograph. This study aimed to examine the analysis of bone fracture healing between osteoblasts and osteoclast numbers and radiographic patterns. Materials and Methods: The study used 12 male Wistar rats with an incomplete fracture in the right femur made by a dental tapered bur with 0.3 mm in length and 0.2 mm in depth. Digital radiographic examinations were carried out on days 0, 5, 10, 17, and 25 after fracturing in a lateral position. Furthermore, a radiographic analysis was performed using Image-J to obtain changes in the value of length and depth in the healing area. The research was conducted to find the radiopaque and radiolucent patterns and the number of osteoblasts and osteoclasts. Results: This study resulted in a change in the radiograph pattern. Callus formation resulted in fracture areas with a smaller distance from day 0 to day 25. The bone healing process begins with granulation tissue formation, followed by the gradual replacement of the connective tissue and bone. This process is comparable to the increase in osteoblasts up to day 25, which blocks bone resorption. Osteoclasts regulate bone resorption, and their number increases after 10 and 17 days to replace bone formation. Osteoclasts decline after 25 days because osteoblasts inhibit them, which control bone formation. Conclusion: The conclusions were obtained there are changes in the radiograph pattern. The radiopaque increased while the radiolucent decreased; the osteoclast pattern tended to be stable and lowered while the osteoblasts increased during the fracture healing process. The correlation of all the factors is very closely related.