Height Restrictions for Dual-energy X-ray Absorptiometry: What Are Our Options for Body Composition and Bone Health Precision?

ABSTRACT: Redinger, AL, Russell, JL, Allen, SMF, and Baker, BS. Height restrictions for dual-energy X-ray absorptiometry: what are our options for body composition and bone health precision? J Strength Cond Res 38(7): e359-e365, 2024-Dual-energy X-ray absorptiometry (DXA) is commonly used for testing athlete's body composition, but many athletes are too tall. The first aim was to assess the viability of combining upper- and lower-body regions of interest (ROI), creating a combined scan for tall athletes who do not fit on the table and second, to provide practical solutions to DXA users who routinely scan tall athletes. Sixty subjects (34.8 ± 11.9 years; 171 ± 9 cm) completed 2 total-body DXA scans for baseline precision testing, using GE Lunar Prodigy (LP) or Hologic Horizon A (HA) models. Next, an upper body ROI from the skull to the distal femoral condyles was combined with a flipped scan (feet-to-head) ROI encompassing the proximal tibial plateau to the distal foot. Soft and bone tissue coefficient of variance (CV%) were calculated between the baseline scans and for the newly combined ROI scan. The combined ROI scan added 0.25-0.63% and 0.01-4.35% error rates for the LP and HA, respectively. An exploratory assessment of a GE Lunar iDXA demonstrated results similar to the HA with 4%+ error. The combined ROI scan is a user-friendly and precise method for older LP systems adding less than 1% error; however, newer DXA systems cannot use the stitched scan technique. Coaches and practitioners who use newer DXAs must prioritize consistently using the same boney landmarks (head, jaw, or feet) and ROI heights to provide precise longitudinal assessments of tall athletes' bone and body composition, until larger DXA tables become available.

[Clinic-X-ray characteristics of periodontal disease in elderly patients.]

The significant prevalence of periodontal diseases in elderly patients makes the research relevant. By now, the issues of complex clinical and radiological semiotics of generalized periodontitis using high-tech research methods is not sufficiently studied. The research addressed the clinical picture and three-dimensional computed tomographic semiotics of severe chronic generalized periodontitis focusing 25 elderly patients with severe chronic generalized periodontitis. It verified the necessity to use an organ-oriented program of multiplanar (volumetric) cone-beam computed tomography coupled with the analysis of the research results, as well as a mandatory analysis of densitometry indicators of the jaw bone tissue in diagnostically significant periodontal zones.

Bone quality assessment in patients with healing mandibular fracture sites: a computed tomography investigation.

The objective of this retrospective study was to assess the bone quality of healing mandibular fracture sites by measuring the Hounsfield units (HU) on computed tomographic (CT) images obtained presurgery and postsurgery in patients treated with rigid internal fixation (RIF). The HU values of healing fracture sites were compared to those of corresponding nonfractured (control) sites on the opposing side and cervical vertebrae sites in the same patients. In total, 31 patients with 45 mandibular fractures treated with RIF underwent presurgical and postsurgical CT examinations. The scans performed after surgery (1, 3, 6, 12, or 18 months) were taken only when there was a need for radiographic evaluation due to a complaint of discomfort from the patient or when the surgeon needed to verify the postsurgical outcome, and each patient underwent only a single postsurgical CT. At the presurgical CT examination, the HU values were lower in the fracture sites than in the control sites. At 3 months postsurgery, the HU values in the fracture sites had increased as the mandibular bone healed. At 6 months postsurgery, the HU values in the fracture sites were higher than those of the control sites. At 12 and 18 months postsurgery, the HU values of both sites were similar. The HU values of the cervical vertebrae remained constant with time. These results suggest that, in patients who have been treated with RIF for mandibular bone fracture, HU values measured by CT vary across time, expressing the physiologic bone healing process.

Hypoxia caused by unilateral nasal obstruction decreases mandibular density in rats through inhibition of Cyp1a1 expression.

BACKGROUND: Oral breathing has an important impact on morphology and bone mineral density (BMD) in a mandible. This study aimed to investigate the hub genes and mechanism regulating the mandibular BMD decrease induced by nasal obstruction. METHODS: A unilateral nasal obstruction model was established in 1-week-old Wistar rats by electrocautery obstruction. BMD of the mandible was determined by micro-computed tomography. Transcriptome analysis was performed to identify differentially expressed genes (DEGs). Hub genes were identified by building protein-protein interaction network and verified by western blot. A hypoxic cell model was established in bone marrow mesenchymal stem cells (BMSCs) by using CoCl2. The expression of hypoxia-inducible factor-1α (HIF-1α), NF-kB ligand-receptor activator (RANKL), osteoprotegerin (OPG), and Cyp1a1 was detected by western blot. RESULTS: The mandibular BMD of rats in the unilateral nasal obstruction group was significantly decreased. A total of 38 DEGs were identified in nasal obstruction rats compared with normal rats. A ratio of RANKL/OPG in the mandible was elevated by nasal obstruction, while the Cyp1a1 was decreased. In vitro, the HIF-1α expression and RANKL/OPG ratio were upregulated by hypoxia while the Cyp1a1 expression was decreased. Pretreatment with Cyp1a1 activator, FICZ, could increase the expression of Cyp1a1 while attenuating the activation of HIF-1α and RANKL. CONCLUSION: Respiratory changes caused by nasal obstruction contribute to the decrease in Cyp1a1 expression in the mandible of juvenile rats, which is associated with disturbances in bone homeostasis controlled by the RANKL/OPG ratio.

Effect of implant composition on periprosthetic bone mineral density after total hip arthroplasty.

BACKGROUND: The severity of bone mineral density (BMD) loss after total hip arthroplasty (THA) depends on both implant- and patient-related factors. While implant fixation type is an important factor, but few studies have considered the effect of material composition on the same implant fixation type. In particular, differences in mechanical stiffness due to material composition are of great interest. Here, we compared changes in periprosthetic BMD after THA using proximal fixation concept stems comprising different titanium alloys, i.e., ß titanium alloys stem and α + ß titanium alloys stem. METHODS: This retrospective cohort included 122 patients (ß titanium alloys stem, 61 cases; α + ß titanium alloys stem, 61 cases) who underwent primary THA between January 2009 and December 2019. The primary outcome was the change in periprosthetic BMD from base line. Age, body mass index, diagnosis, stem size, canal flare index, surgical approach, pre-operative lumbar BMD, and pre-operative activity scores were reviewed and changes in periprosthetic BMD between the two groups were compared using analysis of covariance. The secondary outcome was radiographic response after THA. RESULTS: There was significant difference in periprosthetic BMD in zone 6 and 7 at 2 years (p < 0.05) between the two groups. There was no significant difference in other zones. A significant difference in radiographic response was noted only for the Engh classification. CONCLUSION: α + ß titanium alloys stem resulted in a significantly higher rate of BMD loss in zones 6 and 7 compared with the ß titanium alloys stem. These results may be due to differences in mechanical stiffness due to the different titanium alloy composition of the prosthetics.

New Frontiers in Osteoporosis Therapy.

Current osteoporosis medications reduce fractures significantly but have rare and serious adverse effects (osteonecrosis of the jaw, atypical femoral fractures) that may limit their safety for long-term use. Insights from basic bone biology and genetic disorders have led to recent advances in therapeutics for osteoporosis. New approaches now in clinical use include the antisclerostin monoclonal antibody romosozumab, as well as the parathyroid hormone-related peptide analog abaloparatide. Clinical trial data show significant antifracture benefits with recently approved romosozumab. Studies using abaloparatide build on our longstanding experience with teriparatide and the importance of consolidating the bone mineral density gains achieved from an anabolic agent by following it with an antiresorptive. Combination and sequential treatments using osteoporosis medications with different mechanisms of action have also been tested with promising results. On the horizon is the potential for cell-based therapies (e.g., mesenchymal stem cells) and drugs that target the elimination of senescent cells in the bone microenvironment.

Osteoporosis and periodontal diseases - An update on their association and mechanistic links.

Periodontitis and osteoporosis are prevalent inflammation-associated skeletal disorders that pose significant public health challenges to our aging population. Both periodontitis and osteoporosis are bone disorders closely associated with inflammation and aging. There has been consistent intrigue on whether a systemic skeletal disease such as osteoporosis will amplify the alveolar bone loss in periodontitis. A survey of the literature published in the past 25 years indicates that systemic low bone mineral density (BMD) is associated with alveolar bone loss, while recent evidence also suggests a correlation between clinical attachment loss and other parameters of periodontitis. Inflammation and its influence on bone remodeling play critical roles in the pathogenesis of both osteoporosis and periodontitis and could serve as the central mechanistic link between these disorders. Enhanced cytokine production and elevated inflammatory response exacerbate osteoclastic bone resorption while inhibiting osteoblastic bone formation, resulting in a net bone loss. With aging, accumulation of oxidative stress and cellular senescence drive the progression of osteoporosis and exacerbation of periodontitis. Vitamin D deficiency and smoking are shared risk factors and may mediate the connection between osteoporosis and periodontitis, through increasing oxidative stress and impairing host response to inflammation. With the connection between systemic and localized bone loss in mind, routine dental exams and intraoral radiographs may serve as a low-cost screening tool for low systemic BMD and increased fracture risk. Conversely, patients with fracture risk beyond the intervention threshold are at greater risk for developing severe periodontitis and undergo tooth loss. Various Food and Drug Administration-approved therapies for osteoporosis have shown promising results for treating periodontitis. Understanding the molecular mechanisms underlying their connection sheds light on potential therapeutic strategies that may facilitate co-management of systemic and localized bone loss.

Nanoparticle-mediated selective Sfrp-1 silencing enhances bone density in osteoporotic mice.

Osteoporosis (OP) is characterized by a loss in bone mass and mineral density. The stimulation of the canonical Wnt/ß-catenin pathway has been reported to promote bone formation, this pathway is controlled by several regulators as secreted frizzled-related protein-1 (Sfrp-1), antagonist of the pathway. Thus, Sfrp-1 silencing therapies could be suitable for enhancing bone growth. However, the systemic stimulation of Wnt/ß-catenin has been correlated with side effects. This work hypothesizes the administration of lipid-polymer NPs (LPNPs) functionalized with a MSC specific aptamer (Apt) and carrying a SFRP1 silencing GapmeR, could favor bone formation in OP with minimal undesired effects. Suitable SFRP1 GapmeR-loaded Apt-LPNPs (Apt-LPNPs-SFRP1) were administered in osteoporotic mice and their biodistribution, toxicity and bone induction capacity were evaluated. The aptamer functionalization of the NPs modified their biodistribution profile showing a four-fold increase in the bone accumulation and a ten-fold decrease in the hepatic accumulation compared to naked LPNPs. Moreover, the histological evaluation revealed evident changes in bone structure observing a more compact trabecular bone and a cortical bone thickness increase in the Apt-LPNPs-SFRP1 treated mice with no toxic effects. Therefore, these LPNPs showed suitable properties and biodistribution profiles leading to an enhancement on the bone density of osteoporotic mice.

Bone mineral density and muscle mass in adults with developmental skeletal discrepancies.

BACKGROUND: It was aimed to investigate the musculoskeletal status in individuals diagnosed with skeletal discrepancies. METHODS: This case-control study was performed on 35 patients with developmental skeletal discrepancies listed for orthognathic surgery as a case group and 33 patients who were nominated for wisdom tooth removal as a control group. All participants were aged 18-40 years and the research was carried out in the period between May 2018 and May 2019. Dual X-ray absorptiometry (DEXA) was used to assess bone mass density at three bone sites: total hip, femoral neck, and the spinal lumbar vertebrae (L1-L4). The appendicular muscle mass index (ASMI) was measured based on the four limbs from the DEXA scan. RESULTS: Our data showed that 45.7% (16) of the case group were osteopenic or osteoporotic while in the control group only 21.2% (7) were osteopenic in at least one region (total hip, femoral neck, or lumbar) (p-value = 0.03). Regarding muscle mass, there was significantly lower SMI in subjects with skeletal discrepancies (case group) compared with the control group (median (IQR) 5.9 (2.5) vs. 6.8 (2.9) (kg/m2), respectively, p = 0.04). CONCLUSIONS: There is an essential need for more studies to understand the exact interrelationship between musculoskeletal status and skeletal jaw discrepancies.

Pegbelfermin, a PEGylated FGF21 analogue, has pharmacology without bone toxicity after 1-year dosing in skeletally-mature monkeys.

Pegbelfermin (PGBF) is a PEGylated fibroblast growth factor 21 (FGF21) analogue in development for treatment of nonalcoholic steatohepatitis (NASH). Mouse models highlight potential utility of FGF21 in NASH, but also suggest negative effects on bone, though these findings are confounded by profound FGF21-related decreases in body mass/growth. This study aimed to profile PGBF-related bone effects in adult nonhuman primates after long-term, clinically-relevant exposures. Adult male cynomolgus monkeys received weekly subcutaneous PGBF (0.3, 0.75 mg/kg) or control injections for 1 year (n = 5/group). Assessments included body weight, clinical chemistry, adiponectin levels, bone turnover biomarkers, skeletal radiography, pharmacokinetics, immunogenicity, and histopathology. Bone densitometry and body composition were evaluated in vivo and/or ex vivo with dual-energy x-ray absorptiometry, peripheral quantitative computed tomography, and biomechanical strength testing. After 1 year of PGBF administration, there was clear evidence of sustained PGBF pharmacology in monkeys (peak increase in serum adiponectin of 1.7× and 2.35× pretest at 0.3 and 0.75 mg/kg PGBF, respectively) and decreased body weight compared with control at exposures comparable to those tested in humans. At 0.75 mg/kg PGBF, pharmacologically-mediated reductions in lean mass, lean area, and fat area were observed relative to controls. There were no PGBF-related effects on bone biomarkers, radiography, densitometry, or strength. Together, these data demonstrate that PGBF did not adversely alter bone metabolism, density, or strength following 1 year of dosing at clinically relevant (0.7-2.2× human AUC[0-168 h] at 20 mg once weekly), pharmacologically-active exposures in adult monkeys, suggesting a low potential for negative effects on bone quality in adult humans.

Craniofacial allometry in the OIM-/- mouse model of osteogenesis imperfecta.

Osteogenesis imperfecta (OI) is a skeletal disorder characterized by the impaired synthesis of type I collagen (Col1). This study tests the hypothesis that the craniofacial phenotype of severe OI is linked to an overall reduction in body size. 3D landmark data were collected from µCT scans of adult OIM-/- and wild-type (WT) mice and used to calculate centroid sizes (CS) and interlandmark distances (ILDs). To remove the effect of body size, ILDs were scaled against craniomandibular lengths and CS. Mann-Whitney U tests were used to compare CS and absolute/scaled ILDs between genotypes. OIM-/- mice are smaller than their WT littermates in body mass, craniomandibular CS, and absolute ILDs including skull, basicranial, palatal, mandibular, and toothrow lengths. When linear distances are scaled to CS, OIM-/- mice have a relatively short midface, short nasal bones, tall mandibular corpora, and long mandibular toothrows. Results underscore the importance of size and scaling in morphometric analyses. The deleterious effect of Col1 mutations on global skeletal dimensions combined with localized morphometric changes may underlie the facial phenotype seen in human patients with severe OI. Attempts to identify these localized changes should first account for the restricted growth and small body sizes present in individuals with OI.

Can we enhance osteoporotic metaphyseal fracture healing through enhancing ultrastructural and functional changes of osteocytes in cortical bone with low-magnitude high-frequency vibration?

Fragility fractures are related to the loss of bone integrity and deteriorated morphology of osteocytes. Our previous studies have reported that low-magnitude high-frequency vibration (LMHFV) promoted osteoporotic fracture healing. As osteocytes are known for mechanosensing and initiating bone repair, we hypothesized that LMHFV could enhance osteoporotic fracture healing through enhancing morphological changes in the osteocyte lacuna-canalicular network (LCN) and mineralization. A metaphyseal fracture model was established in female Sprague-Dawley rats to investigate changes in osteocytes and healing outcomes from early to late phase post-fracture. Our results showed that the LCN exhibited an exuberant outgrowth of canaliculi in the osteoporotic fractured bone at day 14 after LMHFV. LMHFV upregulated the E11, dentin matrix protein 1 (DMP1), and fibroblast growth factor 23 (FGF23), but downregulated sclerostin (Sost) in osteocytes. Moreover, LMHFV promoted mineralization with significant enhancements of Ca/P ratio, mineral apposition rate (MAR), mineralizing surface (MS/BS), and bone mineral density (BMD) in the osteoporotic group. Consistently, better healing was confirmed by microarchitecture and mechanical properties, whereas the enhancement in osteoporotic group was comparable or even greater than the normal group. This is the first report to reveal the enhancement effect of LMHFV on the osteocytes' morphology and functions in osteoporotic fracture healing.

Radiographic evaluation of bone density in dentulous and edentulous patients in Riyadh, KSA.

BACKGROUND: The Cone Beam Computed Tomography (CBCT) is currently being used as the most common diagnostic method to evaluate the bone density of the maxilla and the mandible for planning dental implant. Aim: The aim of the study is to check the quantitative alveolar bone density in complete or partial edentulous and dentulous male and female patients among Riyadh sample population in Saudi Arabia. MATERIALS AND METHODS: The study involved a cross-sectional analysis of 231 consecutive CBCT images of 231 different patients (115 males and 116 females). The scans were of Saudi National patients who were partially or completely edentulous without any bone infections in the maxilla and the mandible. The findings are presented as descriptive statistics and inferential statistics: student -t-test for two group means, ANOVA for three groups, Post-hoc LSD test for multiple comparisons, Levene statistics for testing the homogeneity of variances and a statistical significance at 5% level. RESULTS: Comparison of mean alveolar bone density in maxillae of dentulous male smokers showed a statistically significant difference for bucco-cortical plate and cancellous bone among different regions. In dentulous male nonsmokers, no significant difference was observed for maxillary regions, while in mandibular areas, a statistically significant difference was seen for buccal cortex, palatal cortex, and cancellous bone among different regions. While studying the scans of female dentulous patients, a statistically significant difference was observed in alveolar bone density for all the areas. CONCLUSION: Evaluation of bone density is an important step in treatment planning and this study was aimed to provide insight into bone density patterns of population in Riyadh, Saudi Arabia. Further similar studies in different populations can help in planning for more efficient treatment outcomes.

Osteoporosis Changes Collagen/Apatite Orientation and Young's Modulus in Vertebral Cortical Bone of Rat.

This study revealed the distinguished changes of preferential orientation of collagen and apatite and Young's modulus in two different types of osteoporotic bones compared with the normal bone. Little is known about the bone material properties of osteoporotic bones; therefore, we aimed to assess material properties in osteoporotic bones. 66 female Sprague-Dawley rats were used. We analyzed the volumetric bone mineral density, collagen/apatite orientation, and Young's modulus of fifth lumbar vertebral cortex for osteoporotic rats caused by ovariectomy (OVX), administration of low calcium and phosphate content (LCaP) diet, and their combination (OVX + LCaP), as well as sham-operated control. Osteocyte conditions were assessed by hematoxylin and eosin and immunohistochemical (matrix extracellular phosphoglycoprotein (MEPE) and dentin matrix protein 1 (DMP1)) staining. All osteoporotic animals showed bone loss compared with the sham-operated control. OVX improved craniocaudal Young's modulus by enhancing collagen/apatite orientation along the craniocaudal axis, likely in response to the elevated stress due to osteoporotic bone loss. Conversely, LCaP-fed animals showed either significant bone loss or degraded collagen/apatite orientation and Young's modulus. Osteocytes in LCaP and OVX + LCaP groups showed atypical appearance and MEPE- and DMP1-negative phenotype, whereas those in the OVX group showed similarity with osteocytes in the control group. This suggests that osteocytes are possibly involved in the osteoporotic changes in collagen/apatite orientation and Young's modulus. This study is the first to demonstrate that osteoporosis changes collagen/apatite orientation and Young's modulus in an opposite manner depending on the cause of osteoporosis in spite of common bone loss.

An Evaluation of Bone Mineral Density Using Cone Beam Computed Tomography in Patients with Ectodermal Dysplasia: A Retrospective Study at a Single Center in Turkey.

BACKGROUND The aim of this retrospective study was to compare the measurements of bone mineral density (BMD) combined with volumetric dental tomography measurements taken from three main regions selected on the lower mandible, the right mandibular, medial mandibular, and left mandibular regions, in patients with ectodermal dysplasia and age-matched and gender-matched controls. Measurement of BMD in Hounsfield units (HUs) were evaluated using three-dimensional (3D) cone beam computed tomography (CBCT) imaging. MATERIAL AND METHODS Mandibular bone tomography images were evaluated from 9 women and 5 men diagnosed with ectodermal dysplasia and a control group of 9 women and 5 men. The HU values obtained according to age and gender of the total 28 study participants were measured. Statistical analysis of the data used Student's t-test. RESULTS BMD in the ectodermal dysplasia group was significantly lower compared with the BMD in the control group. Comparison of the left and right mandibular angulus regions showed that the BMD of patients with ectodermal dysplasia was significantly lower when compared with the control group in both regions, but no significant difference was found between the two groups in the BMD of the central mandibular region. CBCT was found to be an effective method for the measurement of BMD. CONCLUSIONS In patients with ectodermal dysplasia, reduced BMD should be taken into consideration when planning surgical interventions involving bone tissue and when planning implant surgery. The results of this study may be of value in dentistry and other fields of medicine.

Dental imaging of trabecular bone structure for systemic disorder screening: A systematic review.

The purpose of this systematic review was to evaluate the potential use of dental imaging assessment of trabecular bone structure in the maxillomandibular complex as an adjuvant screening tool to identify systemic disorders. Five electronic databases and grey literature were searched. Studies were included if they investigated subjects with altered trabecular bone determined by dental radiographs. The QUADAS-2 assessed the risk of bias (RoB) among the studies, while the GRADE determined the strength of evidence. A total of 14 studies that included 1,466 individuals were considered eligible for the qualitative analysis. All studies presented an overall low RoB and low concern regarding applicability. Systemic disorders such as osteoporosis, osteogenesis imperfecta, diabetes, and primary hyperparathyroidism, with their respective control groups, were analyzed among the included studies. Osteoporosis was the condition presenting the most significant results, and 72% of the studies detected changes in the maxillomandibular trabecular bone structure. Studies exploring diabetic edentulous patients found less dense trabecular bone pattern (p < 0.05). In summary, periapical and panoramic radiographs, computed tomography, and cone beam computed tomography imaging could be considered useful for the assessment of the mandibular trabecular bone structure of patients affected by osteoporosis and patients with diabetes.

The effect of retraining hypofunctional jaw muscles on the transverse skull dimensions of adult rats.

OBJECTIVE: To experimentally investigate the effects of increased masticatory muscle function on the transverse cranial dimensions on adult rats with an earlier reduced masticatory muscle function. MATERIAL AND METHOD: Sixty young male rats were used. The experimental group received soft diet for a prolonged period, so that the animals developed weak masticatory muscles. A control group received ordinary hard food during the whole experimental period (27 weeks). After 21 weeks when the animals had nearly ceased their body growth the rats in the experimental group were divided into two groups. One group continued with soft diet until the end of the experiment (hypofunctional group). The other group received ordinary hard food to get the possibility to retrain their masticatory muscles (rehabilitation group). At week 21 and at the end of the experimental period (week 27), axial cephalograms were taken. Fourteen landmarks were defined to measure seven transverse distances of the skull. RESULTS: The increase of the anterior zygomatic arch width and interzygomatic width during the experimental period were larger in the rehabilitation group compared to both the normal and the hypofunctional group. CONCLUSION: Retraining of masticatory muscles in adult rats leads to increase of some transverse cranial dimensions.

Development of periprosthetic bone mass density around the cementless Metha® short hip stem during three year follow up-a prospective radiological and clinical study.

PURPOSE: The purpose of this study was to check the concept of the cementless Metha® short hip stem in order to find out whether proximal physiological load transfer can be achieved. METHODS: Fourty-three patients were included. Epidemiological factors were established. The Harris Hip Score was determined and measurement of bone mass density as well as osteodensitometric and radiological measurements was carried out pre-operatively, post-operatively, and after six, 12, 24, and 36 months. RESULTS: Harris Hip Score improved from 55.9 ± 12.4 pre-operatively to 94.8 ± 8.2 after 36 months (p < 0.001). After initial reduction of bone density in zones 1 and 7 up to six months post-operatively, there was a steady approximation of bone density to the initial values (p < 0.05). CONCLUSION: The Metha® short hip stem shows good clinical results. Furthermore, there is an increase of bone density in the proximal zones 1 and 7 between six and 36 months serving as a sign of physiological load transfer.

Effects of micro-osteoperforations on tooth movement and bone in the beagle maxilla.

PURPOSE: The purpose of this study was to determine how micro-osteoperforations (MOPs) affect tooth movements, bone turnover, bone density, and bone volume. METHODS: A split-mouth experimental design with 7 beagle dogs was used to evaluate bone surrounding maxillary second premolars that had been retracted for 7 weeks. One month after the maxillary third premolars were extracted, 8 MOPs (1.5 mm wide and 7 mm deep) were created without flaps with the use of the Propel device (6 were placed 3 mm distal to the second premolar and 2 were placed in the premolar furcation) on one randomly chosen side. The maxillary second premolars were retracted bilaterally with the use of 200 g nickel-titanium closed coil springs. Tooth movements were measured intraorally and radiographically. Microscopic computed tomography was used to evaluate the material density and volume fraction of bone distal to the premolars. Hematoxylin and eosin-stained and fluorescent sections were used to examine the bone remodeling. RESULTS: Neither the intraoral (P = 0.866) nor radiographic (P = 0.528) measures showed statistically significant side differences in tooth movements. There also were no statistically significant differences in the density (P = 0.237) or volume fraction (P = 0.398) of bone through which the premolars were being moved. Fluorescent and histologic evaluations showed no apparent differences in osteoblasts, osteoclasts, or mineralization of bone near the teeth being moved. Bone healing was evident in and near the MOP sites, which had nearly but not completely healed after 7 weeks. Regions of acellular bone were evident extending ∼0.8 mm from the MOP sites. CONCLUSIONS: MOPs placed 3 mm away from teeth do not increase tooth movements and have limited and transitory effect on bone.

A computer aided diagnosis system for measurement of mandibular cortical thickness on dental panoramic radiographs in prediction of women with low bone mineral density.

Osteoporosis detection at earlier stages can enhance the life span of an elderly individual. The aim of the study is to perform semi-automated measurement of mandibular cortical thickness (MCT) on a dental panoramic radiograph (DPR) and thereby to predict the risk of low BMD among the studied population. The study involved 76 women (mean age: 57.2 ± 12.6 years). The DPR was obtained using KODAK 8000C system. The BMD of right total hip (T-BMD) was obtained using DPX Prodigy Dual-energy X-ray absorptiometry (DXA) Scanner. The DPR obtained were subjected to image processing techniques to perform MCT measurement. The region of interest was manually selected around the mental foramen and enhanced using a median filter. The Ostu segmentation was performed and connected component labelling operation was performed to determine the lower boundary by finding the contour with maximum area. Subsequently, the haar wavelet operation was carried out to find the magnitude and thereby select the upper delineating cortical boundary. The Pearson test results revealed (r = 0.96, p < 0.01) for the standard (manual) MCT measurement against the MCT measured using the proposed semi-automated scheme. ROC analysis revealed that MCT = 2.5 mm could be an optimal threshold in spotting individuals at risk of low BMD. The results of the study revealed that the MCT measured on a DPR using the proposed approach could be helpful for identifying individuals at risk of low BMD.