Changes In Trabecular Structure Research Articles

Radiographic texture of the trabecular bone of the proximal phalanx in horses with metacarpophalangeal osteoarthritis.

Osteoarthritis (OA) is a prevalent condition in horses, leading to changes in trabecular bone structure and radiographic texture. Although fractal dimension (FD) and lacunarity have been applied to quantify these changes in humans, their application in horses remains nascent. This study evaluated the use of FD, bone area fraction (BA/TA), and lacunarity in quantifying trabecular bone differences in the proximal phalanx (P1) in 50 radiographic examinations of equine metacarpophalangeal joints with varying OA degrees. In the dorsopalmar view, regions of interest were defined in the trabecular bone of the proximal epiphysis, medial and lateral to the sagittal groove of P1. Lower BA/TA values were observed medially in horses with severe OA (P=0.003). No significant differences in FD and lacunarity were found across OA degrees (P>0.1). FD, BA/TA, and lacunarity were not effective in identifying radiographic texture changes in the P1 trabecular bone in horses with different metacarpophalangeal OA degrees.

Network Modeling Approach for the Nonlinear Dynamics of the Osseous Bio-Physics and Bio-Mathematics

Bone is termed the smart material, and its modeling is of great interest in biomechanics, biochemistry, endocrinology, and oncology. The bone health of cancer patients is directly affected by hormonal imbalances, receptor-mediated tumor-targeted processes, and disturbed bone mineral density. Researchers have used different therapeutic approaches to monitor bone health during and after cancer treatment. This paper describes a reverse process of bone rebuilding after the resorption of bone via cancer treatment. A detailed model is used for hormonal therapy, which leads to the physical changes in trabecular structure. These changes are demonstrated with the aid of artificial neural networks and Petri nets. This paper connects the structural modeling of the bone trabecula with chemical kinetics. The main goal of this study is to provide a PN model of bone metastasis and an analysis of its structural properties. These properties are very helpful in demonstrating the complex dynamics of bone metastasis. Although both ANNs and PNs are well organized in the areas of machine learning and network modeling, neither technique is without limitations. ANNs, for example, are very efficient machine-learning applications, but their utter lack of explanation capabilities classifies them as a “black-box” technique. On the other hand, PNs are an effective modeling technique, but their theory does not include machine learning. This paper provides a hybrid approach to address the two approaches in a novel manner.

Effects of Leptin and Body Weight on Inflammation and Knee Osteoarthritis Phenotypes in Female Rats.

Leptin is a proinflammatory adipokine that contributes to obesity-associated osteoarthritis (OA), especially in women. However, the extent to which leptin causes knee OA separate from the effect of increased body weight is not clear. We hypothesized that leptin is necessary to induce knee OA in obese female rats but not sufficient to induce knee OA in lean rats lacking systemic metabolic inflammation. The effect of obesity without leptin signaling was modeled by comparing female lean Zucker rats to pair fed obese Zucker rats, which possess mutant fa alleles of the leptin receptor gene. The effect of leptin without obesity was modeled in female F344BN F1 hybrid rats by systemically administering recombinant rat leptin versus saline for 23 weeks via osmotic pumps. Primary OA outcomes included cartilage histopathology and subchondral bone micro-computed tomography. Secondary outcomes included targeted cartilage proteomics, serum inflammation, and synovial fluid inflammation following an acute intra-articular challenge with interleukin-1β (IL-1β). Compared to lean Zucker rats, obese Zucker rats developed more severe tibial osteophytes and focal cartilage lesions in the medial tibial plateau, with modest changes in proximal tibial epiphysis trabecular bone structure. In contrast, exogenous leptin treatment, which increased plasma leptin sixfold without altering body weight, caused mild generalized cartilage fibrillation and reduced Safranin O staining compared to vehicle-treated animals. Leptin also significantly increased subchondral and trabecular bone volume and bone mineral density in the proximal tibia. Cartilage metabolic and antioxidant enzyme protein levels were substantially elevated with leptin deficiency and minimally suppressed with leptin treatment. In contrast, leptin treatment induced greater changes in systemic and local inflammatory mediators compared to leptin receptor deficiency, including reduced serum IL-6 and increased synovial fluid IL-1β. In conclusion, rat models that separately elevate leptin or body weight develop distinct OA-associated phenotypes, revealing how obesity increases OA pathology through both leptin-dependent and independent pathways. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Morphologic Mandibular Bone Changes on Panoramic Radiographs of Children and Adolescents with Congenital Heart Disease

Congenital heart disease (CHD) has effects on growth and development. However, information on how the structure of the mandibular bone is affected is limited. In the present study, we aim to compare mandibular bone structures of children affected with CHD and healthy ones through the fractal analysis method and radiomorphometric indices based on panoramic radiographs. The study consisted of 80 children (20 with cyanotic CHD, 20 with acyanotic CHD, 40 control) who were diagnosed with CHD and were treated through interventional therapy or followed up through medical therapy. Fractal dimension (FD) was performed in three different areas (angulus, corpus, and interdental bone) on 80 panoramic radiographs. Additionally, we assessed various radiomorphometric indices: mandibular cortical width (MCW), panoramic mandibular index (PMI), mandibular cortical index (MCI), and simple visual estimation (SVE). p < 0.05 was accepted as statistically significant in the analysis. Values of mean MCW, PMI, MCI, SVE, and FD measurements in children affected with CHD were found to be similar to the control group, regardless of whether they were cyanotic or acyanotic (p > 0.05). In this study, fractal analysis and radiomorphometric indices revealed no trabecular structure and mineral density changes in mandibular bone of children and adolescents with CHD compared to healthy subjects.

Evaluation of bony changes observed in mandibular osteotomy lines and mandibular condyles following bilateral sagittal ramus osteotomy by fractal analysis.

This study aimed to evaluate the surgically impacted trabecular changes in mandibular osteotomy lines and mandibular condyles after bilateral sagittal split ramus osteotomy using the fractal analysis method. The study population consisted of 30 patients (9 male, 21 female) diagnosed with mandibular prognathism and operated with bilateral sagittal split ramus osteotomy under general anesthesia. Fractal analyses observed the alterations on the trabecular structure of osteotomy lines, and mandibular condyles on panoramic radiographs obtained preoperatively, postoperatively, 1st week, 6th month, and 12th month. The box-counting method was used to evaluate the changes in trabecular structure by fractal analysis. P-values of less than 0.05 were considered significant. The fractal dimension values in both osteotomy lines and mandibular condyles were significantly decreased on postoperative 1st week regarding preoperative values. However, fractal dimension values commenced increasing in the following postoperative period. The fractal dimension values of the horizontal and vertical osteotomy lines reached their preoperative values on postoperative 6th and 12th month, respectively. The decreased fractal dimension values observed in the early postoperative period in the right and left condyles reached their preoperative values at the 6th postoperative month. Fractal analyses performed postoperatively can provide information about trabecular changes and bone healing of structures such as osteotomy lines directly affected by bilateral sagittal split ramus osteotomy and indirectly affected mandibular condyles. The results support that fractal analysis can be used together with clinical data in the evaluation of bone healing process.

Evaluation of change in trabecular bone structure surrounding dental implants by fractal dimension analysis and comparison with radiomorphometric indicators: a retrospective study.

BackgroundThe trabecular bone surrounding dental implant show some structural changes during healing period. The purpose of this study is to observe the change in trabecular bone with fractal dimensional analysis from baseline to 3rd month of implant placement. It was also aimed to determine the correlation of fractal dimension (FD) change with morphometric indices, mandibular cortical index (MCI) and mandibular cortical width (MCW).MethodsDigital panoramic radiographs taken from 14 patients were evaluated in this study. A total of 30 implants which were placed on mandibular premolar or molar region were included. MCI and MCW assessments were made on baseline radiograph and FD were analyzed on baseline and 3rd month radiograph. FD change by time was recorded separately for every ROI. A paired sample t-test was used to evaluate the change between FD-baseline and FD-3rdmonth values. One-way ANOVA was used to determine the relationship between FD change and MCI. FD change and MCW measurements correlation was calculated by Pearson correlation analysisResultsFD value increased in 75 of 90 implant-adjacent regions evaluated in the 3rd month and it was observed that the FD values were statistically significantly increased in the mesial, distal and apical regions at the 3rd month measurements. There was no statistically significant relationship between mean FD change and MCI, and there was no correlation between mean FD change and MCW value.DiscussionThere are many studies evaluating the resorptive changes in bone. However, there are few studies investigating whether there is a correlation between pre- and post-operative trabecular pattern with MCI and MCW. The results of this study indicate that the implants have an improving effect on bone trabeculation in the region where they are placed.

Ontogenetic changes to metacarpal trabecular bone structure in mountain and western lowland gorillas.

The trabecular bone morphology of adult extant primates has been shown to reflect mechanical loading related to locomotion. However, ontogenetic studies of humans and other mammals suggest an adaptive lag between trabecular bone response and current mechanical loading patterns that could result in adult trabecular bone morphology reflecting juvenile behaviours. This study investigates ontogenetic changes in the trabecular bone structure of the third metacarpal of mountain gorillas (Gorilla beringei beringei; n = 26) and western lowland gorillas (Gorilla gorilla gorilla; n = 26) and its relationship to expected changes in locomotor loading patterns. Results show that trabecular bone reflects predicted mechanical loading throughout ontogeny. Bone volume fraction, trabecular thickness and trabecular number are low at birth and increase with age, although degree of anisotropy remains relatively stable throughout ontogeny. A high concentration of bone volume fraction can be observed in the distopalmar region of the third metacarpal epiphysis in early ontogeny, consistent with the high frequency of climbing, suspensory and other grasping behaviours in young gorillas. High trabecular bone concentration increases dorsally in the epiphysis during the juvenile period as terrestrial knuckle‐walking becomes the primary form of locomotion. However, fusion of the epiphysis does not take place until 10–11 years of age, and overall trabecular structure does not fully reflect the adult pattern until 12 years of age, indicating a lag between adult‐like behaviours and adult‐like trabecular morphology. We found minimal differences in trabecular ontogeny between mountain and western lowland gorillas, despite presumed variation in the frequencies of arboreal locomotor behaviours. Altogether, ontogenetic changes in Gorilla metacarpal trabecular structure reflect overall genus‐level changes in locomotor behaviours throughout development, but with some ontogenetic lag that should be considered when drawing functional conclusions from bone structure in extant or fossil adolescent specimens.

Skeletal microenvironment system utilising bovine bone scaffold co-cultured with human osteoblasts and osteoclast-like cells.

A three-dimensional ex vivo bone cell culture system mimicking the skeletal system is useful for bone tissue engineering and as drug discovery platforms. The present study aimed to establish a three-dimensional skeletal culture system using native bovine bone scaffolds and human bone cells. Bovine bone scaffolds were cultured with human foetal osteoblasts 1.19 and human peripheral blood mononuclear cells for 21 days under standard culture conditions. The following groups were established: Decalcified unseeded bone scaffold (DUBS) as baseline control, decalcified seeded bone scaffold (DSBS) to mimic osteoporosis condition and undecalcified seeded bone scaffold to mimic normal condition. The scaffold's porosity and cell attachment on the scaffolds were determined using scanning electron microscopy. Histological evaluation was used to examine changes in trabecular bone structure. Dual-energy X-ray absorptiometry analysis was performed to determine the bone mineral density (BMD) and bone mineral content (BMC) of the scaffolds. A compression test was performed to examine the total biomechanical strength of the scaffolds. The trabecular thickness and number increased, while the trabecular separationwas reduced slightly in DSBS than in DUBS (P>0.05). The BMD and BMC increased significantly (P<0.05), while the compressive strength only increased slightly in DSBS than in DUBS (P>0.05). In conclusion, the ex vivo skeletal microenvironment comprising native bovine bone scaffolds seeded with bone cells is structurally, functionally and mechanically comparable with natural bone. This system may be used as a platform to understand bone physiology and screen for potential drug candidates.

Investigation of mandibular fractal dimension on digital panoramic radiographs in bruxist individuals

This study aimed to evaluate changes in mandibular trabecular bone structure in bruxism using fractal analysis on digital panoramic radiographs obtained with automatic dosing. In this prospective study, fractal analysis was performed on radiographs of 126 bruxists and 126 non-bruxists. Eight paired mandibular regions of interest were selected: the bilateral condylar and gonial regions, and the bilateral dentate regions between the apical areas of the first molar and second premolar and between the first premolar and canine. Fractal dimensions (FDs) were calculated at each site. Mean FD values in the bilateral gonial regions of the bruxists were significantly lower than those of controls (P ≤ .049). In both groups, FD values of the right dentate region anterior to the mental foramen were significantly lower than those on the left side (P ≤ .042). Females exhibited significantly lower FD values in both condylar regions in both groups (P ≤ .039) and in the right dentate regions in the controls (P ≤ .022). Correlations between age and FD in all regions were positive but nonsignificant in both groups (P > .05). FD values of mandibular trabecular bone are affected by bruxism in the gonial region and by laterality and sex differences in the condylar and dentate regions.

PKC-\u03b4 deficiency in B cells displays osteopenia accompanied with upregulation of RANKL expression and osteoclast\u2013osteoblast uncoupling

PKC-δ is an important molecule for B-cell proliferation and tolerance. B cells have long been recognized to play a part in osteoimmunology and pathological bone loss. However, the role of B cells with PKC-δ deficiency in bone homeostasis and the underlying mechanisms are unknown. We generated mice with PKC-δ deletion selectively in B cells by crossing PKC-δ-loxP mice with CD19-Cre mice. We studied their bone phenotype using micro-CT and histology. Next, immune organs were obtained and analyzed. Western blotting was used to determine the RANKL/OPG ratio in vitro in B-cell cultures, ELISA assay and immunohistochemistry were used to analyze in vivo RANKL/OPG balance in serum and bone sections respectively. Finally, we utilized osteoclastogenesis to study osteoclast function via hydroxyapatite resorption assay, and isolated primary calvaria osteoblasts to investigate osteoblast proliferation and differentiation. We also investigated osteoclast and osteoblast biology in co-culture with B-cell supernatants. We found that mice with PKC-δ deficiency in B cells displayed an osteopenia phenotype in the trabecular and cortical compartment of long bones. In addition, PKC-δ deletion resulted in changes of trabecular bone structure in association with activation of osteoclast bone resorption and decrease in osteoblast parameters. As expected, inactivation of PKC-δ in B cells resulted in changes in spleen B-cell number, function, and distribution. Consistently, the RANKL/OPG ratio was elevated remarkably in B-cell culture, in the serum and in bone specimens after loss of PKC-δ in B cells. Finally, in vitro analysis revealed that PKC-δ ablation suppressed osteoclast differentiation and function but co-culture with B-cell supernatant reversed the suppression effect, as well as impaired osteoblast proliferation and function, indicative of osteoclast–osteoblast uncoupling. In conclusion, PKC-δ plays an important role in the interplay between B cells in the immune system and bone cells in the pathogenesis of bone lytic diseases.

Chemical effect of bisphosphonates on the bone trabeculate of jaws via fractal dimension

In this contribution, the role of biphosphonate as the fundamental chemical component in newly analyzed biochemical processes is studied, using both fractal dimension analysis on the mathematical and theoretical side, and empirical evaluations of the results of some pathology problems. The main goal of this paper is to throw some empirical evidence that patients who underwent bisphosphonate based treatments may experience changes in their trabecular bone densities that worsens whenever there are radiolucent injuries caused by invasive dental procedures. As such, we conducted a comparative study between two groups of subjects, namely, people who had general and dental health conditions, and patients with certain pathologies that were being treated with bisphosphonates and even had suffered osteonecrosis. We analyzed a collection of CBCT images obtained routinely throughout the oral examination process. We use fractal dimension as an appropriate tool to detect changes in both trabecular structure and bone density. Our results highlighted significant differences between both groups. As a consequence, we postulate that bisphosphonate based treatments may provoke chemical reactions at a bone level whose changes could be quantified by routine radiological studies.

Effect of icariin on early steroid-induced osteonecrosis of the femoral head in rabbits

To explore the effect of icariin on early steroid-induced osteonecrosis of the femoral head in rabbits. Fifty mature New Zealand rabbits (weighing, 2.5-3.0 kg) were randomly divided into control group ( n=10), model group ( n=20), and experimental group ( n=20). The rabbits of model and experimental groups were injected with lipopolysaccharide and methylprednisolone to establish the animal model of early steroid-induced osteonecrosis of the femoral head. The rabbits of experimental group were feeded with icariin solution once a day for 6 weeks since the first injection of methylprednisolone, whereas the rabbits of control and model groups were given normal saline at the same time points. The left femoral heads were removed after 6 weeks and gross morphological features were evaluated. Micro-CT scan was performed to analyze the trabecular microstructure with the following parameters: trabecular bone volume to total volume (BV/TV), trabecular number (Tb.N), trabecular thickness (Tb.Tn), and trabecular separation (Tb.Sp). The Micro-CT scan was also converted to three-dimensional reconstruction images for observation. HE staining was applied to observe the trabecular structure and morphological changes of osteocytes and marrow adipocytes. It was also used to determine whether the samples of femoral heads occurred osteonecrosis based on the criteria for pathological diagnosis, and calculate the rate of empty lacunae. Seven rabbits died during the study, and 9, 16, and 18 rabbits in the control, model, and experimental groups, respectively, enrolled the final analysis. Compared with control group, the femoral head collapse and trabecular breaks were more obvious, and the trabeculae were sparse with irregular arrangement in the model group according to the results of gross observation, Micro-CT scan, and three-dimensional reconstruction images. But in the experimental group, the surface of femoral head was slight shrinking without obvious collapse, and the degeneration of trabecular structure was mild. According to bone microstructures analysis, the Tb.N, Tb.Tn, and BV/TV of femoral head in model and experimental groups were lower than those in control group, while the Tb.Sp in the model and experimental groups were significantly higher. The Tb.N, Tb.Tn, and BV/TV of femoral head in experimental group were higher than those in model group, while the Tb.Sp in the experimental group was significantly lower. The differences between groups were all significant ( P<0.05). In the model group, HE staining showed that the number of osteocytes reduced, the number of empty lacunae increased, and the marrow adipocytes piled up in the space between femoral trabeculae, some even mashed together like a cyst. In the experimental group, the trabecular structure was still relatively complete compared with model group, no obvious apoptosis of osteocytes was observed, the size and number of adipocytes were basically normal. None of the animals in control group occurred osteonecrosis of the femoral head based on the criteria for pathological diagnosis, and the incidence of osteonecrosis were 81.3% (13/16) in the model group and 66.7% (12/18) in the experimental group, and the difference was not significant ( P=0.448). The rate of empty lacunae of osteonecrotic femoral heads in the model group was 33.1%±1.4%, which was higher than that in experimental group (18.9%±0.8%) and in control group (12.7%±1.5%), and the differences between groups were significant ( P<0.05). The icariin has a protective effect on the early steroid-induced osteonecrosis of the femoral head in rabbits, which can decrease osteocytes apoptosis, improve the bone microstructure, and delay such disease processes.

Multiscale effects of spaceflight on murine tendon and bone.

Despite a wealth of data on the effects of spaceflight on tendons and bones, little is known about its effects on the interfacial tissue between these two structures, the enthesis. Mice were sent to space on three separate missions: STS-131, STS-135, and Bion-M1 to determine how spaceflight affects the composition, structure, mechanics, and gene expression of the humerus-supraspinatus and calcaneus-Achilles entheses. At the nanoscale, spaceflight resulted in decreased carbonate levels in the bone, likely due to increased remodeling, as suggested by increased expression of genes related to osteoclastogenesis (CatK, Tnfsf11) and mature osteoblasts (Col1, Osc). Tendons showed a shift in collagen fibril size towards smaller diameters that may have resulted from increased expression of genes related to collagen degradation (Mmp3, Mmp13). These nanoscale changes did not result in micro- and milliscale changes to the structure and mechanics of the enthesis. There were no changes in bone volume, trabecular structure, failure load, or stiffness with spaceflight. This lack of tissue-level change may be anatomy based, as extremities may be less sensitive to spaceflight than central locations such as vertebrae, yet results highlight that the tendon enthesis may be robust against negative effects of spaceflight.

The Effects of Quassinoid-Rich Eurycoma longifolia Extract on Bone Turnover and Histomorphometry Indices in the Androgen-Deficient Osteoporosis Rat Model.

Male osteoporosis is associated with higher rates of disability and mortality. Hence the search for suitable intervention and treatment to prevent the degeneration of skeletal health in men is necessary. Eurycoma longifolia (EL), a traditional plant with aphrodisiac potential may be used to treat and prevent male osteoporosis. The skeletal protective effect of quassinoid-rich EL extract, which has a high content of eurycomanone, has not been studied. This study aimed to determine whether EL could prevent skeletal deteriorations in gonadal hormone-deficient male rats. Ninety-six male Sprague–Dawley rats were randomly assigned to baseline, sham-operated (Sham), orchidectomised or chemically castrated groups. Chemical castration was achieved via subcutaneous injection of degarelix at 2 mg/kg. The orchidectomised and degarelix-castrated rats were then divided into negative control groups (ORX, DGX), testosterone-treated groups (intramuscular injection at 7 mg/kg weekly) (ORX + TES, DGX + TES), and EL-supplemented groups receiving daily oral gavages at doses of 25 mg/kg (ORX + EL25, DGX + EL25), 50 mg/kg (ORX + EL50, DGX + EL50), and 100 mg/kg (ORX + EL100, DGX + EL100). Following 10 weeks of treatment, the rats were euthanized and their blood and femora were collected. Bone biochemical markers, serum testosterone, osteoprotegerin (OPG), and receptor activator of nuclear factor kappa β-ligand (RANKL) levels and histomorphometric indices were evaluated. Quassinoid-rich EL supplementation was found to reduce degenerative changes of trabecular structure by improving bone volume, trabecular number, and separation. A reduction in the percentage of osteoclast and increase in percentage of osteoblast on bone surface were also seen with EL supplementation. Dynamic histomorphometric analysis showed that the single-labeled surface was significantly decreased while the double-labeled surface was significantly increased with EL supplementations. There was a marginal but significant increase in serum testosterone levels in the ORX + EL25, DGX + EL50, and DGX + EL100 groups compared to their negative control groups. Quassinoid-rich EL extract was effective in reducing skeletal deteriorations in the androgen-deficient osteoporosis rat model.

Trabecular structural changes in the mandibular condyle caused by degenerative osteoarthritis: a comparative study by cone-beam computed tomography imaging.

Temporomandibular osteoarthritis causes pain and loss of function. In advanced cases, it may also result in destruction of joint cartilage surfaces and bone structure. This study was performed to examine the potential changes in the condylar trabecular bone structure in patients with temporomandibular osteoarthritis. Condylar trabecular structures were compared between 35 healthy patients and 35 patients with temporomandibular osteoarthritis by a box-counting method using fractal dimensional analysis on cone-beam computed tomography images. The average fractal dimensions of patients with temporomandibular osteoarthritis and healthy patients were 1.18 and 1.23, respectively. This difference was statistically significant (p ≤ 0.05). Our results add to the existing preliminary knowledge regarding the osteoporotic changes that occur in the trabecular structure under the subchondral bone, which is normally not seen on radiographic images, as well as the destruction and remodeling that occur on the condyle surface, which is visible on radiographic images.

Association of sickle cell haemoglobinopathies with dental and jaw bone abnormalities.

To estimate the association between sickle cell anaemia and trait with dental and jaw bone abnormalities. Subjects (n=369) were allocated to three groups: sickle cell anaemia, trait and control. Dental shape, number, size and position and changes in pulp chamber, root and periapex were analysed by intra-oral periapical radiographs. Integrity of lamina dura, quality of cancellous bone and bone trabeculation were also evaluated. Prevalence ratios (PR) were calculated (α=0.05). Sickle cell anaemia had higher prevalence (PR:8.31) and number of teeth (PR:13.40) with external resorption; higher number of teeth with pulp calcification; partial and total loss of lamina dura; and higher prevalence of changes in trabecular structure of maxilla (PR:6.45) and mandible (PR:5.34). Sickle cell trait showed higher prevalence (PR:1.26) and higher number of teeth (PR:1.98) with partial loss of lamina dura; higher number of teeth with hypercementosis, changes in shape, size, periapex, total loss of lamina dura; and higher prevalence of changes in mandibular trabecular bone (PR:1.43). Pulp calcification and external resorption of the root were the most frequent dental alterations in sickle cell anaemia group, while in trait was higher frequency of changes in shape, size, periapex and root. Jaw bone changes were most prevalent in both homozygous and heterozygous subjects.

Evaluation of trabecular structure changes in osteoarthritis of the temporomandibular joint with cone beam computed tomography imaging

To explore the possibility of using 2-dimensional image assessments in combination with cone beam computed tomography (CBCT) in patients with temporomandibular joint osteoarthritis (TMJOA) to enhance the clinical significance and applicability of the CBCT findings on TMJOA changes. Fifty-two patients with unilateral TMJOA and 40 healthy adults who had undergone CBCT in preparation for orthodontic treatment were selected for this study. Temporomandibular joint images were acquired with CBCT. All images were classified into 4 phases (slight erosion, widespread erosion, appearance of bone maintenance, and partial loss of condylar head with a remodeled cortical surface) and 4 levels of severity (absent, slight, moderate, and extensive). Quantitative microstructural analysis, including bone value fraction (BV/TV), trabecular number (Tb.N), trabecular thickness, and trabecular separation (Tb.Sp) of each image, was performed by using a customized software. In patients with unilateral TMJOA, the affected side had significantly higher BV/TV and Tb.N and significantly lower Tb.Sp compared with the unaffected side. Compared with healthy individuals, the affected joints in patients with TMJOA had significantly higher BV/TV and trabecular thickness and significantly lower Tb.N and Tb.Sp. No significant difference was found among different phase groups or different severity levels. CBCT combined with a software investigation protocol for microstructure measurement can be used to provide reliable trabecular parameters in assessing TMJOA.

Microarchitecture of Schlemm Canal Before and After Selective Laser Trabeculoplasty in Enhanced Depth Imaging Optical Coherence Tomography.

To characterize the in vivo effect of selective laser trabeculoplasty (SLT) on the Schlemm canal (SC) in eyes with primary open-angle glaucoma (POAG). Eighty-one serial horizontal enhanced depth imaging optical coherence tomograph B-scans (interval between B-scans, ∼35 μm) of the nasal corneoscleral limbus were obtained before and 4 weeks after SLT. Fifty B-scans in the overlapping regions before and after SLT were selected for analysis based on the structures of aqueous and blood vessels as landmarks. The SC cross-sectional area (CSA) was measured in each selected B-scan and averaged to generate the mean SC CSA of the eye. SC volume in the overlapping region was calculated using commercially available 3-dimensional reconstruction software. The mean SC CSA and SC volume were compared between pre-SLT and post-SLT B-scans. Correlation analysis was performed between SC CSA changes and intraocular pressure (IOP) changes. Thirteen POAG eyes (13 patients) were included for analysis (mean age, 68.2±9.2 y). After SLT, the mean IOP was reduced from 19.8±7.6 to 14.4±3.8 mm Hg (P=0.003); the mean SC CSA increased by 8%, from 2478±550 to 2682±598 μm (P=0.029); and the mean SC volume increased from 4,304,592±954,777 to 4,658,250±1,039,956 μm (P=0.029). Increase in SC CSA had a significant positive correlation with IOP reduction after SLT (P=0.023, R=0.622). SLT expands SC in POAG patients and even more so with greater IOP reduction after SLT. Post-SLT expansion of SC may be due to increased trabecular aqueous outflow, IOP decrease, or structural changes in trabecular meshwork resulting from SLT.

Age- and Sex-Dependent Changes of Intra-articular Cortical and Trabecular Bone Structure and the Effects of Rheumatoid Arthritis

The objective of this cross-sectional study was to define normal sex- and age-dependent values of intra-articular bone mass and microstructures in the metacarpal heads of healthy individuals by high-resolution peripheral quantitative computed tomography (HR-pQCT) and test the effect of rheumatoid arthritis (RA) on these parameters. Human cadaveric metacarpal heads were used to exactly define intra-articular bone. Healthy individuals of different sex and age categories and RA patients with similar age and sex distribution received HR-pQCT scans of the second metacarpal head and the radius. Total, cortical, and trabecular bone densities as well as microstructural parameters were compared between 1) the different ages and sexes in healthy individuals; 2) between metacarpal heads and the radius; and 3) between healthy individuals and RA patients. The cadaveric study allowed exact definition of the intra-articular (intracapsular) bone margins. These data were applied in measuring intra-articular and radial bone parameters in 214 women and men (108 healthy individuals, 106 RA patients). Correlations between intra-articular and radial bone parameters were good (r = 0.51 to 0.62, p < 0.001). In contrast to radial bone, intra-articular bone remained stable until age 60 years (between 297 and 312 mg HA/cm3 ) but decreased significantly (p < 0.001) in women thereafter (237.5 ± 44.3) with loss of both cortical and trabecular bone. Similarly, RA patients showed significant (p < 0.001) loss of intra-articular total (263.0 ± 44.8), trabecular (171.2 ± 35.6), and cortical bone (610.2 ± 62.0) compared with sex- and age-adjusted controls. Standard sex- and age-dependent values for physiological intra-articular bone were defined. Postmenopausal state and RA led to significant decrease of intra-articular bone. © 2016 American Society for Bone and Mineral Research.

Stiffness and strength of bone in osteoporotic patients treated with varying durations of oral bisphosphonates.

Apparent modulus and failure stress of trabecular bone structure from 45 women with osteoporosis treated with bisphosphonates for varying durations were studied using finite element analyses and statistical modeling. Following adjustments for patient age and bone volume, increasing bisphosphonate treatment duration for up to 7.3years was associated with treatment-time-dependent increases in bone apparent modulus and failure stress. Treatment durations exceeding 7.3years were associated with time-dependent decreases in apparent modulus and failure stress from the peak values observed. The purpose of this study was to clarify the relationship between bisphosphonate (BP) treatment duration and human bone quality. This study quantified changes in the apparent modulus and failure stress of trabecular bone biopsied from patients with osteoporosis who were treated with BPs for widely varying durations. Forty-five iliac crest bone samples were obtained from women with osteoporosis who were continuously treated with oral BPs for varying periods of up to 16years. Micro-CT imaging was used to develop three-dimensional virtual models of the trabecular bone from these samples. Apparent modulus and failure stress of these virtual models were determined using finite element analyses (FEA). Polynomial regression and cubic splines, adjusted for relevant (age and BV/TV) covariates, were used to statistically model the data and quantify the relationships between BP treatment duration and apparent modulus or failure stress. Second-order polynomial models were needed to relate apparent modulus or failure stress to BP treatment duration. These models showed that these bone quality parameters (a) increased with increasing BP treatment duration up to approximately 7.3years, (b) reached a maximum at this (~7.3years) time, and then (c) declined with BP treatment durations exceeding ~7.3years. A similar result was obtained by modeling with cubic splines. Changes in FEA-derived apparent stiffness and failure stress are attributable to changes in trabecular bone structure, which in turn are related to the duration of BP treatment. These relationships are evident even after adjustments are made in the statistical models for changes in age and BV/TV. According to these models, increases in trabecular bone apparent stiffness and failure stress linked to BPs cease and appear to reverse after approximately 7.3years of treatment. Conclusions regarding optimal BP therapy duration await study of additional bone quality parameters.