Bone Density Analysis Research Articles

Forensic age estimation in adults based on multidetector computed tomography analysis of bone density in the medial meta-epiphyseal region of clavicle.

The aim of this study was to investigate the potential of using multidetector computed tomography (MDCT) to measure the bone mineral density (BMD) in the medial meta-epiphyseal region of clavicle (MERC) for adult age estimation. A total of 1064 chest MDCT scans from individuals aged 21 to 102years were utilized to determine the MERC BMD. The Mimics software was used for the BMD measurements, and the average BMD of both MERC was also calculated. Regression analysis was conducted with chronological age as a dependent variable and MERC BMD as an independent variable to establish a mathematical model for age estimation. The mean absolute error (MAE) was calculated to evaluate the accuracy of the regression model using an independent validation sample. Among all the models, the cubic regression model showed the highest correlation between MERC BMD and chronological age and also provided the most accurate age prediction for both males and females (MAE = 9.41 for males, MAE = 10.38 for females). Our study suggests that BMD measured by MERC can be utilized for age estimation in adults when more reliable indicators are not available.

Machine Learning Models Can Define Clinically Relevant Bone Density Subgroups based on Patient Specific Calibrated CT Scans in Patients Undergoing Reverse Shoulder Arthroplasty

Reduced bone density is recognized as a predictor for potential complications in reverse shoulder arthroplasty (RSA). While humeral and glenoid planning based on preoperative computed tomography (CT) scans assist in implant selection and position, reproducible methods for quantifying the patients' bone density are currently not available. The purpose of this study was to perform bone density analyses including patient specific calibration in an RSA cohort based on preoperative CT imaging. It was hypothesized that preoperative CT bone density measures would provide objective quantification of the patients' humeral bone quality. This study consisted of three parts, (1) analysis of a patient-specific calibration method in cadaveric CT scans, (2) retrospective application in a clinical RSA cohort, and (3) clustering and classification with machine learning models. Forty cadaveric shoulders were scanned in a clinical CT and compared regarding calibration with density phantoms, air muscle, and fat (patient-specific) or standard Hounsfield unit. Post-scan patient-specific calibration was used to improve the extraction of three-dimensional regions of interest for retrospective bone density analysis in a clinical RSA cohort (n=345). Machine learning models were used to improve the clustering (Hierarchical Ward) and classification (Support Vector Machine (SVM)) of low bone densities in the respective patients. The patient-specific calibration method demonstrated improved accuracy with excellent intraclass correlation coefficients (ICC) for cylindrical cancellous bone densities (ICC>0.75). Clustering partitioned the training data set into a high-density subgroup consisting of 96 patients and a low-density subgroup consisting of 146 patients, showing significant differences between these groups. The SVM showed optimized prediction accuracy of low and high bone densities compared to conventional statistics in the training (accuracy=91.2%; AUC=0.967) and testing (accuracy=90.5 %; AUC=0.958) data set. Preoperative CT scans can be used to quantify the proximal humeral bone quality in patients undergoing RSA. The use of machine learning models and patient-specific calibration on bone mineral density demonstrated that multiple 3D bone density scores improved the accuracy of objective preoperative bone quality assessment. The trained model could provide preoperative information to surgeons treating patients with potentially poor bone quality.

Exploring bone density analysis on routine CT scans as a tool for opportunistic osteoporosis screening

The primary aim of this study was to evaluate computed tomography (CT)-based bone density analysis at the level of thoracic vertebra 12 (Th12) as a screening method for decreased bone density in patients admitted to the intensive care unit (ICU). Interobserver variability was analyzed. Secondary aims were to assess the prevalence of CT-based low bone density upon ICU admission in a cohort of COVID-19 patients and to assess the potential effect of long-term ICU stay on bone density in these patients. Retrospective single-center cohort study. ICU of the Leiden University Medical Center (LUMC), the Netherlands. Patients admitted to the ICU of the LUMC between March 1st, 2020 and February 1st, 2022 with a diagnosis of COVID-19, and a length of ICU stay of ≥ 21 days. In the included patients both baseline chest CT scans (obtained upon ICU admission) and follow-up chest CT scans (obtained ≥ 21 days after ICU admission) were available for analysis. A total of 118 CT scans in 38 patients were analyzed. There was a good interobserver variability, with an overall mean absolute difference (between measurements of three observers) of 9.7 Hounsfield Units (HU) and an intraclass correlation coefficient (ICC) of 0.93 (95% CI 0.88–0.96). The effect of intravenous contrast administration on bone density measurements was small (+ 7.5 HU (95% CI 3.4–11.5 HU)) higher in contrast enhanced CT images compared to non contrast enhanced CT images). Thirty-seven percent of patients had a bone density < 140 HU, suggestive of osteoporosis. No significant difference was found between bone density upon ICU admission and bone density at follow-up (≥ 21 days after ICU admission). Vertebral CT-based bone density analysis using routine CT scans is an easily applicable method to identify ICU patients with decreased bone density, which could enable enrollment in osteoporosis prevention programs. A high prevalence of low bone density was found in our cohort of ICU patients. There were no changes observed in bone density between baseline and follow-up measurements.

Establishing a Murine Osteoporosis Protocol for Biomaterials Testing

Osteoporosis is one of the most common disorders of bone metabolism, this being a condition that causes pain, frequently causing fractures, as a result of the reduction of bone mass and density. The purpose of this study is the establishment and testing of an experimental protocol to induce osteoporosis in laboratory rats by ovariectomy, at 9 months old. It is desirable that osteoporosis is successfully induced so that various biomaterials for treating pathologic bone healing can be further tested. For this study, 20 Sprague-Dawley rats were split into 2 groups of 10 individuals, which were then operated, while 10 were left as control. Clinical examination was performed each week, but mainly 4 months after surgery, biochemistry and osteodensitometry were determined by CT - scanning to compare the differences between the ovariectomized group and the control group. The rats were humanly euthanasied at 20 weeks post ovariectomy and histological analyses were performed. Biochemistry revealed that progesterone level was decreased by ~50%, calcium values were decreased, alkaline phosphatase was increased and the Ca:P ratio was also altered. Nevertheless, the analysis of bone density (BMD) revealed a decrease in the ovariectomized group compared with the control group and the histological analysis confirmed the induction of osteoporosis pathology. In conclusion, osteoporosis by means of estrogenic deficit, was successfully induced in 9-month-old Sprague-Dawley rats.

Suppression of bone resorption by Mori Radicis Cortex through NFATc1 and c-Fos signaling-mediated inhibition of osteoclast differentiation.

Mori Radicis Cortex (MRC) is the root bark of the mulberry family as Morus alba L. In Korea, it is known as "Sangbaegpi". Although MRC has demonstrated anti-inflammatory and antioxidant effects, its specific mechanisms of action and impact on osteoporosis remain poorly understood. To investigate the antiosteoporosis effect of MRC, we examined the level of osteoclast differentiation inhibition in receptor activator of nuclear factor kappa-Β ligand (RANKL)-induced-RAW 264.7 cells and animal models of ovariectomy (OVX) with MRC. Serum analysis in OVX animals was investigated by enzyme-linked immunosorbent assay (ELISA), and bone density analysis was confirmed by micro-computed tomography (micro-CT). The expression analysis of nuclear factor of activated T cells 1 (NFATc1) was confirmed by immunohistochemistry (IHC) in femur tissue. In addition, osteoclast differentiation inhibition was measured using tartrate-resistant acid phosphatase (TRAP). mRNA analysis was performed using reverse transcription-polymerase chain reaction (RT-PCR), and the protein expression analysis was investigated by western blot. Micro-CT analysis showed that MRC effectively inhibited bone loss in the OVX-induced rat model. MRC also inhibited the expression of alkaline phosphatase (ALP) and TRAP in serum. Histological analysis showed that MRC treatment increased bone density and IHC analysis showed that MRC significantly inhibited the expression of NFATc1. In RANKL-induced-RAW 264.7 cells, MRC significantly reduced TRAP activity and actin ring formation. In addition, MRC significantly inhibited the expression of NFATc1 and c-Fos, and suppressed the mRNA expression. Based on micro-CT, serum and histological analysis, MRC effectively inhibited bone loss in an OVX-induced rat model. In addition, MRC treatment suppressed the expression of osteoclast differentiation, fusion, and bone resorption markers through inhibition of NFATc1/c-Fos expression in RANKL-induced RAW 264.7 cells, ultimately resulting in a decrease in osteoclast activity. These results demonstrate that MRC is effective in preventing bone loss through inhibiting osteoclast differentiation and activity.

Abstract 5387: Host-derived CCL2 drives prostate cancer bone metastasis via CCND2/STAT3 pathway

Abstract Overexpression of tumor-derived CCL2 has been shown to partially promote prostate cancer (PCa) bone metastasis, but the function of host-derived CCL2 is not fully understood. We first developed a mouse model using intracardiac injection and obtained highly metastatic PCa cell subclones through in vivo selection. The highly metastatic tumor cells were injected intracardially into CCL2 knockout (CCL2 KO) mice and wild-type (WT) controls, and the tumor cell growth and metastasis were monitored weekly by bioluminescence imaging. The osteolytic lesions were evaluated by radiography, micro-computed tomography (microCT) and immunohistochemistry (IHC) staining. The cells in the bone microenvironment were analyzed by flow cytometry. Also, RNA sequencing (RNA-seq) analysis was performed on the cells either from CCL2 KO mice or WT controls. We found that a loss of host-derived CCL2 significantly retarded tumor growth in bone and prolonged mouse survival. In addition, bone density analysis revealed a decrease in osteolytic lesion in CCL2 KO mice, compared to WT controls. Systemically, CCL2 deficiency reduced the proportion of granulocyte-myeloid-derived suppressor cell (G-MDSC) populations with immunosuppressive function and decreased the PCa conditioned medium (CM)-induced osteoclast formation. The enrichment analysis revealed that the dysregulated genes in bone metastatic cells from CCL2 KO mice were significantly enriched in several biological processes, including vitamin metabolism, monoatomic anion homeostasis, immune response, and bone growth. Additionally, we also confirmed that the CCND2/STAT3 pathway is apparently suppressed in the cells from CCL2 KO mice. This study demonstrated that targeting the host-derived CCL2 might be a novel potential anti-metastatic approach. Supported by the NSFC projects (81972766, 81972420, 82173336), as well as grants from the Science and Technology Project of Shenzhen (JCYJ20190809161811237, JCYJ20210324104214040). Key words Host-derived CCL2; Prostate cancer; Bone metastasis; osteoclast; CCND2 Citation Format: Jie Meng, Ming Chang, Siyuan Qin, Xin Huang, Weiping Liang, Haibo Tong, Jian Zhang. Host-derived CCL2 drives prostate cancer bone metastasis via CCND2/STAT3 pathway [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5387.

Correlation of CT-based bone mineralization with drilling-force measurements in anatomical specimens is suitable to investigate planning of trans-pedicular spine interventions

This interdisciplinary study examined the relationship between bone density and drilling forces required during trans-pedicular access to the vertebra using fresh–frozen thoraco-lumbar vertebrae from two female body donors (A, B). Before and after biomechanical examination, samples underwent high-resolution CT-quantification of total bone density followed by software-based evaluation and processing. CT density measurements (n = 4818) were calculated as gray values (GV), which were highest in T12 for both subjects (GVmaxA = 3483.24, GVmaxB = 3160.33). Trans-pedicular drilling forces F (Newton N) were highest in L3 (FmaxB = 5.67 N) and L4 (FmaxA = 5.65 N). In 12 out of 13 specimens, GVs significantly (p < 0.001) correlated with force measurements. Among these, Spearman correlations r were poor in two lumbar vertebrae, fair in five specimens, and moderately strong in another five specimens, and highest for T11 (rA = 0.721) and L5 (rB = 0.690). Our results indicate that CT-based analysis of vertebral bone density acquired in anatomical specimens is a promising approach to predict the drilling force appearance as surrogate parameter of its biomechanical properties by e.g., linear regression analysis. The study may be of value as basis for biomechanical investigations to improve planning of the optimal trajectory and to define safety margins for drilling forces during robotic-assisted trans-pedicular interventions on the spine in the future.

The Density-Weighted Foot Center Is Different to the Geometric Foot Center

Category: Basic Sciences/Biologics; Hindfoot Introduction/Purpose: It has become a reality with the advent of weight bearing CT (WBCT) that weight bearing (WB) is a significant element to be considered when analyzing foot and ankle images. Some knowledge has begun to accumulate on the effect of WB on bone positioning, but the effect of WB on bone mineral density (BMD) distribution, apart from being a long for accepted truth since the works of Julius Wolff, could not until now be visualized other than on the biological level. Now, Hounsfield Units allow for bone density analysis on WBCT. The objective of the study was to compare the relative positions of the geometric foot center (GC) and the density-weighted foot center (DC). We hypothesized those to be different. Methods: Ethics approval was obtained. Thrity two feet from our WBCT database were retrospectively randomly selected (Curvebeam Pedcat, Hatfield PA, USA). Datasets were analyzed using Bonelogics software (Disior, Paragon 28, USA). Bone segmentation was performed to obtain all bone orientations and volumes excluding tibia and fibula and all phalanges. The data was computed to obtain the geometric centers (from bone surface coordinates), which were considered as reference and were given a value of 0. Therefore density-weighted centers (from all bone data including density) were calculated. The difference between the two centers represented the shift which was assessed along the sagittal axis (anterior shift), transversal axis (lateral shift) and craniocaudal axis (upward shift). Statistical analysis was conducted using STATA package. Results: The mean age and Body Mass Index of the cohort were 57.2 ± 9.6 years and 22.2 ± 2.8 kg/m2, respectively. The 3D displacement vector between GC and DC had a norm of 10.01 mm. We found that DC was significantly shifted anteriorly by 8.9 ± 0.3 mm (range, 5.6 mm to 13.4 mm), medially by 0.4 ± 0.8 mm (range, -1.3 mm to 0.3 mm) and upwardly by 4.2 ± 0.14 mm (range, 2.8 mm to 5.9 mm) (p &lt; 0.001 in all cases). Conclusion: Our hypothesis was confirmed: the geometric and weighed foot centers were different. DC was more anteriorly and slightly medially situated. Both centers were situated at the interface between the talus and cuboid. The more anterior position may be explained by the fact that human foot is responsible for anteriorly orientated longitudinal movement on average. We deem that BMD is a significant dimension in WBCT datasets that cannot be ignored in the development of new measurement tools that are not currently standardized. Alignment based purely on bone outer shape without considering BMD may not be representative of their true biomechanical state.

Reliability of Grayscale Value for Bone Density Determination in Oral Rehabilitation using Dental Implants.

Quality and quantity of jaw bones have been previously classified in literature using different methods. Imaging modalities such as computed tomography (CT), successfully determine bone density of jaws. This study aims to establish the role of cone-beam CT (CBCT) in determining the density of cortical and cancellous bones at different jaw sites. Eighty-three possible implant sites in healthy patients were evaluated using NewTomGiano CBCT machine. Cross-sections were obtained and cortical and cancellous bone densities on different aspects of the virtual implant in terms of Hounsfield unit (HU) were determined using New Net Technologies software version 6.1 and were classified according to software from D1 to D4. Data were entered into SPSS software (version 19.0) and were statistically analyzed. The mean HU showed the highest value for cortical and cancellous in the anterior mandible (mean HU 1874.01 and 1131.73, respectively) followed by the posterior mandible (mean HU 1789.20 and 872.95, respectively) and least in posterior maxilla (mean HU 1068.26 and 830.04, respectively). Maximum D1 bone type was found in cortical bone and D2 bone type was noted in cancellous bone area. Males showed very highly significant cortical bone thickness (P < 0.001) whereas females showed more cancellous bone thickness but the results were nonsignificant. A high degree of concordance between different regions of jaw bones with a strong correlation between the four bone types was obtained. Bone density plays a pivotal role in determining the prognosis of the implant. CBCT has proven to be beneficial in bone density analysis.

Analysis of Bone Density and Bone Morphometry by Periapical Radiographs in Dental Implant Osseointegration Process.

This research aimed to analyze the differences in bone density and bone morphometry by periapical implant radiography in the dental implant osseointegration stages. This experimental research uses 12 periapical radiographs of tibial bones from a New Zealand white rabbit (Oryctolagus cuniculus). The analysis was performed on day 3, 14, and 28 of the osseointegration stages with density, trabecular thickness (Tb.Th.), trabecular separation (Tb.Sp.), and trabecular number (Tb.N.) as parameters. The implant used is a titanium alloy and coated by SA (sunblasted with alumina acid) of 4 mm in diameter and 7 mm in length. The radiographic assessment of the osseointegration process is obtained with the region of interest (ROI) segmentation results. Additionally, each ROI was analyzed for bone density and morphometry using the open-source ImageJ software with the BoneJ plugin. The significant difference was evaluated by analysis of variance (F-test) with p < 0.05 and nonparametric Kruskal-Wallis test with p < 0.05. Analysis of the osseointegration images of dental implants at day 3, 14, and 28 with the periapical X-ray modality shows significant differences (p < 0.05) in the parameters measuring density and trabecular thickness (Tb.Th.). In the variables of trabecular separation (Tb.Sp.) and number (Tb.N.) (p > 0.05), there is no significant difference. Based on the results, density and trabecular thickness (Tb.Th.) showed a significant difference between healing times. However, trabecular separation (Tb.Sp.) and trabecular number (Tb.N.) showed no difference in healing time.

Micro-CT evaluation of bone grow concept of an implant with microstructured backtaper crestally and sub-crestally placed. Preliminary study in New Zealand rabbits tibia at one month

&lt;abstract&gt; &lt;p&gt;The primary purpose of this study was to determine the accuracy of micro-computed tomography (micro-CT) as a novel tool for the 3D analysis of bone density around dental implants in tibia rabbits. Six male New Zealand rabbits were used in our evaluation. One Copa SKY® (Bredent Medical GmbH &amp;amp; Co. K.G.) with a 3.5 mm diameter by 8.0 mm in length was placed within 12 tibia rabbits divided into two experimental groups: Group A (crestal placement) and Group B (sub-crestal placement). The animals were sacrificed at four weeks. Micro-CT evaluations showed a high amount of bone around all implants in the tibia rabbit bone. There was an increased formation of bone around the Copa SKY implants, mainly in the implants that were placed crestally. The most frequent density found in most implants was a medullary bone formation surrounding the implant; the density three (D3) was the most common type in all implants. The 3D model analysis revealed a mean bone volume (B.V.) of 31.24 ± 1.24% in crestal implants compared with the 43.12 ± 0.43% in sub-crestal implants. The mean actual contact implant to bone (B.I.C.) in the sub-crestal group was 51.76 ± 0.86%, compared to the 42.63 ± 0.75% in the crestal group. Compared to crestal implants, the Copa Sky implant placed sub-crestally allows for the formation of bone on top of the neck, thereby stimulating bone growth in tibia rabbits.&lt;/p&gt; &lt;/abstract&gt;

Internal calibration for opportunistic computed tomography muscle density analysis.

Muscle weakness can lead to reduced physical function and quality of life. Computed tomography (CT) can be used to assess muscle health through measures of muscle cross-sectional area and density loss associated with fat infiltration. However, there are limited opportunities to measure muscle density in clinically acquired CT scans because a density calibration phantom, allowing for the conversion of CT Hounsfield units into density, is typically not included within the field-of-view. For bone density analysis, internal density calibration methods use regions of interest within the scan field-of-view to derive the relationship between Hounsfield units and bone density, but these methods have yet to be adapted for muscle density analysis. The objective of this study was to design and validate a CT internal calibration method for muscle density analysis. We CT scanned 10 bovine muscle samples using two scan protocols and five scan positions within the scanner bore. The scans were calibrated using internal calibration and a reference phantom. We tested combinations of internal calibration regions of interest (e.g., air, blood, bone, muscle, adipose). We found that the internal calibration method using two regions of interest, air and adipose or blood, yielded accurate muscle density values (< 1% error) when compared with the reference phantom. The muscle density values derived from the internal and reference phantom calibration methods were highly correlated (R2 > 0.99). The coefficient of variation for muscle density across two scan protocols and five scan positions was significantly lower for internal calibration (mean = 0.33%) than for Hounsfield units (mean = 6.52%). There was no difference between coefficient of variation for the internal calibration and reference phantom methods. We have developed an internal calibration method to produce accurate and reliable muscle density measures from opportunistic computed tomography images without the need for calibration phantoms.

Radiodensity Analysis of Lateral Column Superconstruct Fixation Sites in Midfoot Charcot Neuroarthropathy

Lateral column deterioration and subsequent loss of function poses a challenge for limb preservation in patients with Charcot neuroarthropathy (CN). Application of “superconstructs” provides stability and clinical improvement to an often-ulcerated lateral foot. This study examines radiodensity in Hounsfield units (HU) to compare bone quality of lateral column fixation targets using computed tomography (CT) scans between patients with and without midfoot CN. A retrospective chart review identified control (nondiabetic, non-CN; n = 29) and midfoot CN (n = 21) groups. Patient demographics and medical history were collected. Two reviewers measured the mean HU of circular regions of interest centered on the fourth and fifth metatarsal heads as well as the anterior, middle, and posterior thirds of the calcaneus. Radiodensity was compared between groups, among calcaneal locations, Eichenholtz stages and Brodsky types. A p value ≤.05 was considered statistically significant. Age and body mass index were not significantly different between groups. The CN group exhibited greater HU than the control group at the metatarsal head and calcaneus (p < .001). The anterior calcaneus exhibited greater HU than the posterior calcaneus in the CN group (p = .02). The difference in HU was not statistically significant between Stages 0-1 and Stages 2-3 or midfoot Brodsky Types. Indirect bone density analysis revealed an increased density in CN compared to control patients with no significant difference between midfoot CN stages or types. The anterior calcaneus was the densest rearfoot bone among the CN patients, a result that may have implications in surgical fixation.

Predicting Pedicle Screw Pullout and Fatigue Performance: Comparing Lateral Dual-Energy X-Ray Absorptiometry, Anterior to Posterior Dual-Energy X-Ray Absorptiometry, and Computed Tomography Hounsfield Units.

As the prevalence and associated health care costs of osteoporosis continue to rise in our aging population, there is a growing need to continue to identify methods to predict spine construct integrity accurately and cost-effectively. Dual-energy x-ray absorptiometry (DEXA) in both anterior to posterior (AP) and lateral planes, as well as computed tomography (CT) Hounsfield units (HU), have all been investigated as potential preoperative predictive tools. The purpose of this study is to determine which of the 3 bone density analysis modalities has the highest potential for predicting pedicle screw biomechanics. Lumbar spine specimens (L2, L3, and L4) from 6 fresh frozen cadavers were used for testing. AP-DEXA, lateral-DEXA, and CT images were obtained. Biomechanical testing of pedicle screws in each vertebrae was then performed including pullout strength and fatigue testing. Statistical analysis was performed. Pullout strength was best predicted by CT HU, followed by AP-DEXA, then lateral-DEXA (R 2 = 0.78, 0.70, and 0.40, respectively). Fatigue testing showed a significant correlation of relative rotation between HU value and AP-DEXA bone mineral density (R 2 = 0.54 and R 2 = 0.72, respectively), and there was a significant correlation between relative translation and HU value (R 2 = 0.43). There was a poor correlation between relative rotation and lateral-DEXA (R 2 = 0.13) as well as a poor correlation between relative translation and both AP- and lateral-DEXA (R 2 = 0.35 and R 2 = 0.02). CT is the only modality with a statistically significant correlation to all biomechanical parameters measured (pullout strength, relative angular rotation, and relative translation). AP-DEXA also predicts the biomechanical measures of screw pullout and relative angular rotation and is superior to lateral-DEXA. CT may provide an incremental benefit in assessing fatigue strength, but this should be weighed against the disadvantages of cost and radiation. The results of this study can help to inform clinicians on different bone density analyses and their implications on pedicle screw failure.

Analysis of CBCT Bone Density Using the Hounsfield Scale

Assessing bone density in prospective dental implant sites is crucial both for choosing the implant type and for planning a drilling procedure that will ensure the implant’s primary stability and osseointegration. This study aimed to investigate possible differences between the bone densities of various edentulous sites in the maxilla and mandible. The study was conducted on a group of forty partly edentulous patients who underwent radiological examination by scanning the areas of interest using cone beam computed tomography (CBCT). Hounsfield units (HU) were analyzed using dedicated software. Higher HU were observed at the site of mandibular central incisors compared to the site of maxillary central incisors. The HU values in the mandibular first molars region were higher than those of the maxillary first molars. Buccal vs. lingual or palatal cortical HU values did not differ significantly. Within the limitations of this study, it can be stated that an objective assessment of site-specific bone density before the installation of dental implants may provide valuable clinical information for the selection of implant size and the planning of a patient-specific drilling protocol.

Correlation of Lisfranc Injuries With Regional Bone Density

Lisfranc injuries present a challenge due to their ubiquity though frequent missed diagnoses. A paucity of data exists associating the contribution of bone density to injury type. This investigation compares the regional bone density between Lisfranc injury types using computed-tomography (CT)-derived Hounsfield units. A retrospective chart review identified patients with gross ligamentous and avulsion-type Lisfranc injuries determined by CT examination of the second metatarsal base and medial cuneiform. Regional bone density was assessed by averaging the Hounsfield units of the first metatarsal base, navicular, cuboid, calcaneus, and talus between 2 reviewers. Density was compared between injury type, isolated concomitant forefoot, and mid/hindfoot fractures. One hundred thirty-four patients were separated into avulsion (n = 85) and ligamentous (n = 49) groups. No statistically significant difference in patient body mass index, age, smoking status, or Quenu and Kuss injury pattern was observed between groups. The regional bone density of the cuboid (p = .03) and talus (p = .04) was greater in the ligamentous group. Lower extremity concomitant mid/hindfoot fracture patients exhibited greater regional bone density in the ligamentous group in all assessed bones (p ≤ .04) except the calcaneus. Ligamentous injuries of the Lisfranc complex are associated with increased regional bone density among patients sustaining concomitant mid/hindfoot fractures. This study expands the utility of regional bone density analysis in foot and ankle trauma.

Biomechanical Analysis of Different Framework Design, Framework Material and Bone Density in the Edentulous Mandible With Fixed Implant-Supported Prostheses: A Three-Dimensional Finite Element Study.

The objective of this finite element study was to investigate the effect of different framework designs, framework materials, and bone densities on the stress distribution of fixed implant-supported prostheses for edentulous mandibles. Under the condition of 2-mm cortical bone, 16 models were created in the edentulous mandible to simulate different framework designs (1-piece or 3-piece frameworks) with different framework material (pure titanium, zirconia, polyetheretherketone, or carbon fiber-reinforced polyetheretherketone) in-high or low-density trabecular bone. Then, vertical loading and oblique loading at 75° were applied to the anterior and posterior regions. The stress distribution and stress concentration region of implant and peri-implant bone with different combinations were compared by finite element analysis. The use of the 1-piece zirconia framework in high-density trabecular bone improved stress distribution on implants and peri-implant bone. The region of stress concentration is located in thebuccal cervix of the distal implants and the distobuccal portion of the cortical bone in all models. To improve the stress distribution on fixed implant-supported dentures for edentulous mandibles, the 1-piece framework and zirconia represent the better combination. Under the condition of 2-mm cortical bone thickness, the full-arch zirconia framework had minimum von Mises stress on implants and peri-implant bone in all models, and high trabecular bone density greatly decreased the stress on cortical bone.

Advanced platelet-rich-fibrin (A-PRF +) has no additional effect on the healing of post-extraction sockets of upper third molars. A split mouth randomized clinical trial.

This study evaluated the effects of advanced platelet-rich fibrin (A-PRF +) on the healing of upper third molar post-extraction sockets. Sixteen patients who underwent extractions of the upper third molars (18 and 28) were included in this randomized split-mouth study. The alveoli on the test side were filled with A-PRF + , while the control side was maintained with blood clot. The side that received treatment was randomly defined. Alveolar bone regeneration was evaluated by CBCT scans to assess healing stage, bone density, and fractal analysis 1week and 90days post-extraction. Additionally, pain, edema, bleeding, and soft tissue alveolar repair were evaluated by clinical analyses 3, 7, 14, 30, and 90days after the surgical procedure using a visual analog scale. There were no clinical differences regarding treatments in any experimental period. In the tomographic evaluation, at 7days, the alveoli treated with A-PRF + presented a suggestive sign of higher bone density than the control alveoli, which was not confirmed 90days after the surgical procedure. Thus, the use of A-PRF + does not demonstrate a clinical advantage in the repair of post-extraction sockets of upper third molars.

The Importance of Correlation between CBCT Analysis of Bone Density and Primary Stability When Choosing the Design of Dental Implants-Ex Vivo Study.

This study aims to determine the correlation between the mean value of bone density measured on the CBCT device and the primary stability of dental implants determined by resonant frequency analysis. An experimental study was conducted on a material of animal origin: bovine femur and pig ribs. Two types of implants were used in this study: self-tapping and non-self-tapping of the same dimensions. Results of the experimental study showed a statistically significant correlation between bone density expressed in HU units and the primary stability of self-tapping and non-self- tapping dental implants expressed in ISQ units in bovine femur bones and self-tapping implants and pig rib bones. There was no statistically significant correlation between non-self-tapping dental implants in pig rib bones. Self-tapping and non-self-tapping implants did not show statistical significance in the primary stability in bones of different qualities. The analysis of bone density from CBCT images in the software of the apparatus expressed in HU units can be used to predict the degree of primary stability of self-tapping and non-self-tapping dental implants in bones of densities D1 and D2, and self-tapping dental implants in bones of the lower quality D4.

COMPARATIVE ANALYSIS OF DENS ITOMETRIC DETERMINATION OF BONE TISSUE IN THE CASE OF LOSS OF THE MASTICATORY TEETH OF THE MANDIBLE

Conducting densitometric studies aimed at objectifying and improving the accuracy of estimating the structural parameters of the bone become fundamental in the rehabilitation of patients to meet their functional, prosthetic and aesthetic needs. Today, the results of bone density analysis determine the priority in choosing a new method of direct implantation with immediate load or search for an alternative to existing ones that guarantee the predictability of the result concerning the physiological terms of osteogenesis, directed bone regeneration and other reconstructive surgical interventions. Based on 243 computed tomographic digital scans taken by the VaTech PaX-I 3D Green extraoral system, bone density was analyzed in conventional grayness units (CGU) in the projection of the missing 3.7, 3.6, 4.6, 4.7 teeth and 136 studies were selected as objects for this work, which provide proper information and signifi cant cognitive importance. The maximum mineralization of bone tissue in the toothless distal areas of the lower jaw, both on the left and right sides, was established in individuals of the fi rst study group (25-45 years) with values of pronounced density on sagittal sections of horizontal planes in the projection of 3.6 tooth M=1246.6±63.13 CGU and in projection 4.6 tooth, where M=1158.8±47.04 CGU. The lowest values of bone density were determined in individuals of the third study group (61-75 years) on sagittal sections of vertical planes in projections of 3.7 tooth, where M=736.8±42.63 CGU, and 4.7 tooth, where M=778.8±51.79 CGU. The result of the analysis of this work confi rms the hypothesis of age-related dependence of changes in bone density on the time of tooth loss. It was found that early loss of the masticatory teeth leads to high indicators, with an increase in bone density towards distalization of the terminal defect of dentition. Conversely, the lack of functional action on bone tissue leads to a decrease in its density in the age aspect, and, accordingly, the exhaustion of the trabecular layer, which contributes to the progression of atrophic processes.