Midpalatal Suture Density CBCT Evaluation, Sex Gender and Growth Pattern Related Variability in 392 Adolescents Treated With Rapid Maxillary Expander Appliance

The aim of this paper was to evaluate the changes in the mean bone density values of the midpalatal suture in 392 young patients treated with the Rapid Palatal Expander appliance according to sex, gender, vertical and sagittal skeletal patterns. Materials and Methods. The evaluations were performed using the low-dose protocol cone-beam computed tomography scans at t0 (preoperatively) and t1 (1 year after the beginning of the therapy). The region of interest was used to calculate bone density in Hounsfield units (HU) in the area between the maxillary incisors. Results. CBCT scan data of 196 females and 196 males (mean age of 11,7 years) showed homogeneous and similar density values of the MPS at T0 (547.59 HU - 565.85 HU) and T1 (542.31 - 554.20 HU). Class III skeletal individuals showed a significant higher BD than the II class group at T0, but not at T1. Females showed significantly higher BD than males at t0 and t1. No significant differences were found between the other groups and between two-time points in terms of bone density values of the MPS. Conclusions. Females and III class groups showed significantly higher bone density values than males and II class, respectively. No statistically significant differences were found from T0 to T1 in any groups, suggesting that a similar rate of suture reorganization occurs after the use of the RPE, following reorganization and bone deposition along with the MPS.

Medullary bone in male budgerigars (Melopsittacus undulatus) with testicular neoplasms

Medullary bone is a calcium-rich, labile bone normally occurring in female birds with each egg-laying cycle. The stimulus for formation of medullary bone is, in part, the cyclic increase in serum estrogens produced by preovulatory ovarian follicles. Increased bone density due to formation of medullary bone, particularly in pneumatic bones, has been termed polyostotic hyperostosis, even if physiologic. This study investigated the formation of medullary bone in nonpneumatic (femur) and pneumatic (humerus) bones in sexually mature male budgerigars submitted for autopsy. Of the 21 sexually mature male budgerigars submitted for autopsy, 7 (33%) had medullary bone in 1 or more bones examined. All 7 male budgerigars with medullary bone had a testicular neoplasm, which was morphologically consistent with a testicular sustentacular cell tumor, seminoma, or interstitial cell tumor. Medullary bone was not present in the 14 cases with other diseases. Medullary bone formation in pneumatic and nonpneumatic bones can occur in male budgerigars with testicular neoplasms. Radiographic increases in medullary bone density, particularly in the humerus, could provide antemortem indication of testicular neoplasia in male budgerigars.

Can routine MRI spine T1 sequences be used for prediction of decreased bone density?

Background Bone marrow signal is ideally evaluated with magnetic resonance imaging (MRI) due to its high tissue contrast. While advanced MRI quantitative methods can be used for estimating bone density, there are no readily available parameters on routine clinical MRI sequences of the lumbar spine. Purpose To evaluate whether T1 signal intensity (SI) ratio of lumbar vertebral body (VB)/cerebrospinal fluid (CSF) may predict decreased bone density. Material and Methods A retrospective study was conducted. After use of inclusion/exclusion criteria, 36 patients who had an MRI scan of the lumbar spine and a DEXA scan performed as a part of annual health visit were selected. T1 SI of the lumbar vertebral bodies and adjacent CSF were recorded. Ratio of T1 SI of L1–L4 (VB)/CSF was calculated. The corresponding bone-density values on DEXA scan measured as g/cm2 were obtained. Pearson's r correlation statistic was used to determine the correlation between these variables. Results T1 VB/T1 CSF SI ratio was between 1.308 and 2.927 (mean = 2.028). Mean T1 SI value of vertebral bodies (L1–L4) was 264.9 and mean CSF SI value was 131.9. Bone density in g/cm2 was between 0.851 and 1.398 (mean = 1.081). Pearson correlation coefficient was r = −0.619 ( P=0.0001), which shows a negative moderate correlation between the T1 VB/T1 CSF SI ratio and bone density. Conclusion A high T1 VB/T1 CSF SI ratio on routine MRI sequences may indicate decreased bone density. This ratio may be of substantial benefit in unsuspected osteoporosis/osteopenia on routine MRI lumbar spine imaging.

Bone density may affect primary stability of anterior cruciate ligament reconstruction when organic core bone plug fixation technique used

Purpose Core Bone Plug Fixation (CBPF) technique is an implant-less methodology for ACL reconstruction. This study investigates the effect of bone density on CBPF stability to identify the bone quality that is likely to benefit from this technique. Methods Artificial blocks with 160 (Group 1), 240 (Group 2), and 320 (Group 3) kg/m3 densities were used to simulate human bone with diverse qualities. These groups are representative of the elderly, middle age and young people, respectively. A tunnel was made in each test sample using a cannulated drill bit which enabled harvesting the core bone plug intact. Fresh animal tendon grafts were prepared and passed through the tunnel, so the core bone was pushed in to secure the tendon. The fixation stability was tested by applying a cyclic load following by a pullout load until the failure occurred. The selected group was compared with interference screw fixation technique as a gold standard method in ACL reconstruction. Results The Group 2 stiffness and yield strength were significantly larger than Group 1. The graft slippage of Group 1 was significantly less than Group 3. The ultimate strengths were 310 N and 363 N, in Groups 2 and 3, significantly larger than that of Group 1. The ultimate strength in fixation by interference screw was 693.18 N, significantly larger than the bone plug method. Conclusions The stability of CBPF was greatly affected by bone density. This technique is more suitable for young and middle-aged people. With further improvements, the CBPF might be an alternative ACL reconstruction technique for patients with good bone quality. Clinical relevance The CBPF technique offers an implant-less organic ACL reconstruction technique with numerous advantages and likely would speed up the healing process by using the patient’s own bones and tissues rather than any non-biologic fixations.

Oral administration of melatonin increases plasma calcium and magnesium and improves bone metabolism in aged male mice

We previously reported that the oral administration of melatonin from 4 to 20 months to male mice improved femoral bone strength and bone density during the aging. Additionally, melatonin receptor, MT2, was immunologically detected in both osteoblasts and osteoclasts of the mouse femoral bone. Thus, melatonin can act on both osteoblasts and osteoclasts to maintain bone strength during the aging process. Here, we analyzed plasma calcium (Ca2+), magnesium (Mg2+), and inorganic phosphorus ([PO4]3-) in 20-month-old male mice with or without administration melatonin (15-20 mg/kg/day) in drinking water. We found that plasma Ca2+ and Mg2+ levels in melatonin-treated mice increased significantly as compared with control mice. In [PO4]3-, melatonin administration tended to increase its plasma level, but did not reach statistical significance. The potential association between these divalent ions and metabolism markers of femoral bone was also examined. In the femoral diaphysis, the plasma Ca2+ and Mg2+ concentrations were positively correlated with periosteal and endosteal circumference which were significantly associated with the Strength Strain Index. Therefore, melatonin treatment enlarged femoral diaphysis and enhanced bone strength by increasing mineral depositions. In addition, the plasma melatonin levels were significantly positive correlation with total bone density and critical thickness in the femoral diaphysis. Since we had not observed the primary trabecular bone and osteoclasts in 20-month-old mice previously, it is suggested that plasma Ca2+ and Mg2+ are not elevated due to bone resorption. The increased plasma Ca2+ and Mg2+ by melatonin may originate from the intestinal absorption of these ions since melatonin binds to the vitamin D3 receptor, its activation is known to promote the intestinal absorption of Ca2+.

The Effect of Different Implant-Abutment Mis-Matches on Stress Distribution: A 3-Dimensional Finite Element Study

Platform-switching reduces peri-implant marginal bone loss (MBL), and the aim of this study was to compare the effect of platform-switching on stress within crestal bone using different implant-abutment mis-matches (0.65 and 1mm) under two different vertical loads (30 N vs 200 N) for implants placed in posterior jaw sites. 3-D modeling software was used for an implant of 4.5mm diameter and 13mm length. Molars were modeled using CT images of bone density in human maxilla (D3 bone) and mandible (D2 bone). Collected data were analyzed using CATIA software. In posterior mandible, stress of 30 N force with platform mis-matches of 0.65 or 1mm were 2.920 and 2.440 MPa respectively. Using 200 N force, values increased to 19.44 and 16.30 MPa. In posterior maxilla and 30 N force, stresses with mis-matches of 0.65 and 1mm were 3.77 and 3.18 MPa respectively increasing to 25.14 & 20.17 with 200 N force. The effect can be predicted to be greatest as the mis-match increases with implants placed into lower quality bone (posterior maxilla with D3 quality).

Weakening or Structural Strengthening? An Evaluation of Bone Density after MRgFUS Ablation for Treatment of Benign Bone Lesions

Previous studies suggest that interventional ablative procedures on bone lesions may weaken the bone, especially when performed through the needle approach. Our purpose was to evaluate, through Computed Tomography (CT), the effects of Magnetic Resonance guided Focused Ultrasound Surgery (MRgFUS) ablation on painful osteoid osteomas and osteoblastomas in terms of bone density and morphological changes. We retrospectively evaluated patients treated at our institution with MRgFUS for superficial, painful osteoid osteoma or osteoblastoma during the last 9 years. Inclusion criteria were procedural and clinical success, as well as the availability of pre- and postprocedural CT examinations. Imaging features assessed were perilesional/nidus density changes and the occurrence of pathological fractures during the follow-up period. Our study population included 31 osteoid osteomas and 5 intra-articular osteoblastomas in 36 treated patients. We found an increased bone density of the lesions when pre and post-treatment CT- values were compared: these differences were statistically significant, and this finding is consistent with significant bone densification at the post-treatment imaging follow-up. No pathological fractures were observed after ablation during the follow-up. MRgFUS can be considered to be the treatment of choice for benign superficial bone lesions, thanks to its minimal invasiveness, excellent effectiveness, and safety. Pathological fractures, reported in literature as a rare event using needle ablation, never occurred in our MRgFUS treatment series.