Maximum Bone Research Articles

Therapeutic approach in periimplantitis

Peri–implantitis is a frequent a polyetiological disease. Currently its treatment is a challenge, the treatment algorithms still being unclear. Purpose of the study: Evaluation of etiological factors of complications in implant– prosthetic rehabilitation and comparative analysis of available management methods. Materials and methods: 47 patients and 108 implants were included in the study. The parameters of interest were: gender, age of the patients, number of affected implants, spreading of peri–implantitis according to the teeth position and distribution between the jaws, possible etiological factors, distribution of defects according to Schwarz classification, level of bone resorption, applied treatment. Results: Among 34 treated implants, an improvement was achieved in 6 cases, among 72 extracted implants favourable conditions were obtained in all cases. Priority is given to maximum bone preservation and the possibility of subsequent replantation. Radical surgical treatment in extensive defects shows greater predictability than conservative treatment.

Craniofacial Fibrous Dysplasia in Fronto-Orbital Region: A Single-Center Retrospective Study of 38 Cases

This study presents the clinical characteristics, imaging manifestations, and surgical experience in 38 patients diagnosed with craniofacial fibrous dysplasia in fronto-orbital region (foFD). We retrospectively analyzed the clinical data from 38 patients who had surgery for foFD. The surgical procedure typically involved extensive tumor removal, followed by immediate reconstruction of the frontal bone and orbit using synthetic materials. Additionally, 9 patients underwent simultaneous microscopic decompression of the optic canal. Common clinical manifestations included progressive fronto-orbital bone deformity (35), proptosis (28), orbital dystopia (21), and visual impairment (9). The disease primarily affecting the frontal bone (38), the sphenoid bone (28), and the ethmoid bone (24). The optic canal was involved in 9 patients with functional impairment. Computed tomography scans in all 38 cases revealed satisfactory repair material positioning and complete resolution of frontal deformities. Among the 9 patients who underwent optic canal decompression, 7 experienced partial recovery of visual acuity after surgery. In the surgical treatment of foFD, it is crucial to achieve maximal bone resection and repair skull defects, while decompressing the optic canal can provide significant benefits for patients with decreased visual function preoperatively. The use of preformed artificial materials offers advantages in aesthetic restoration after lesion excision.

BORS/BJR TRAVELLING FELLOWSHIP ABSTRACT: THE EFFECT OF INCREASING BONE LOSS ON THE PRIMARY STABILITY OF METAPHYSEAL SLEEVES IN THE PROXIMAL TIBIA. AN EXPERIMENTAL STUDY USING SAWBONE TIBIAS

AbstractApproximately 20% of primary and revision Total Knee Arthroplasty (TKA) patients require multiple revisions, which are associated with poor survivorship, with worsening outcomes for subsequent revisions. For revision surgery, either endoprosthetic replacements or metaphyseal sleeves can be used for the repair, however, in cases of severe defects that are deemed “too severe” for reconstruction, endoprosthetic replacement of the affected area is recommended. However, endoprosthetic replacements have been associated with high complication rates (high incidence rates of prosthetic joint infection), while metaphyseal sleeves have a more acceptable complication profile and are therefore preferred. Despite this, no guidance exists as to the maximal limit of bone loss, which is acceptable for the use of metaphyseal sleeves to ensure sufficient axial and rotational stability. Therefore, this study assessed the effect of increasing bone loss on the primary stability of the metaphyseal sleeve in the proximal tibia to determine the maximal bone loss that retains axial and rotational stability comparable to a no defect control.Methodsto determine the pattern of bone loss and the average defect size that corresponds to the clinically defined defect sizes of small, medium and large defects, a series of pre-operative x-rays of patients with who underwent revision TKA were retrospectively analysed. Ten tibiae sawbones were used for the experiment. To prepare the bones, the joint surface was resected the typical resection depth required during a primary TKA (10mm). Each tibia was secured distally in a metal pot with perpendicular screws to ensure rotational and axial fixation to the testing machine. Based on X-ray findings, a fine guide wire was placed 5mm below the cut joint surface in the most medial region of the plateau. Core drills (15mm, 25mm and 35mm) corresponding to small, medium and large defects were passed over the guide wire allowing to act at the centre point, before the bone defect was created. The test was carried out on a control specimen with no defect, and subsequently on a Sawbone with a small, medium or large defect. Sleeves were inserted using the published operative technique, by trained individual using standard instruments supplied by the manufacturers. Standard axial pull-out (0 – 10mm) force and torque (0 – 30°) tests were carried out, recording the force (N) vs. displacement (mm) curves.ResultsA circular defect pattern was identified across all defects, with the centre of the defect located 5mm below the medial tibial base plate, and as medial as possible. Unlike with large defects, small and medium sized defects reduced the pull-out force and torque at the bone-implant interface, however, these reductions were not statistically significant when compared to no bony defect.ConclusionsThis experimental study demonstrated that up to 35mm radial defects may be an acceptable “critical limit” for bone loss below which metaphyseal sleeve use may still be appropriate. Further clinical assessment may help to confirm the findings of this experimental study. This study is the first in the literature to aim to quantify “critical bone loss” limit in the tibia for revision knee arthroplasty.Declaration of Interest(a) fully declare any financial or other potential conflict of interest

Candy box technique for the fixation of inferior pole patellar fractures: finite element analysis and biomechanical experiments

BackgroundMaintaining effective reduction and firm fixation in inferior pole patellar fractures is a highly challenging task. There are various treatment methods available; although tension-band wiring combined with cerclage wiring (TBWC) is the mainstream approach, its effectiveness is limited. Herein, we propose and evaluate a new technique called candy box (CB), based on separate vertical wiring (SVW), for the treatment of inferior pole patellar fractures. Specifically, we provide biomechanical evidence for its clinical application.MethodsFive fixation models were built: SVW combined with cerclage wiring (SVWC); TBWC; modified SVW with the middle (MSVW-A) or upper (MSVW-B) 1/3 of the steel wire reserved, and CB. A finite element analysis was performed to compare the displacement and stress under 100-N, 200-N, 300-N, 400-N and 500-N force loads. Three-dimensional printing technology was utilized to create fracture models, and the average displacement of each model group was compared under a 500-N force.ResultsThe results of the finite element analysis indicate that CB technology exhibits significantly lower maximum displacement, bone stress, and wire stress compared to that with other technologies under different loads. Additionally, in biomechanical experiments, the average force displacement in the CB group was significantly smaller than that with other methods under a 500-N force (P < 0.05).ConclusionsCB technology has the potential to overcome the limitations of current techniques due to its superior biomechanical characteristics. By incorporating early functional exercise and ensuring strong internal fixation, patient prognosis could be enhanced. However, further clinical trials are needed to fully evaluate the therapeutic effects of CB technology.

Finite element analysis of five internal fixation modes in treatment of Day type Ⅱcrescent fracture dislocation of pelvis

To compare the biomechanical differences among the five internal fixation modes in treatment of Day type Ⅱ crescent fracture dislocation of pelvis (CFDP), and find an internal fixation mode which was the most consistent with mechanical principles. Based on the pelvic CT data of a healthy adult male volunteer, a Day type Ⅱ CFDP finite element model was established by using Mimics 17.0, ANSYS 12.0-ICEM, Abaqus 2020, and SolidWorks 2012 softwares. After verifying the validity of the finite element model by comparing the anatomical parameters with the three-dimensional reconstruction model and the mechanical validity verification, the fracture and dislocated joint of models were fixed with S 1 sacroiliac screw combined with 1 LC-Ⅱ screw (S 1+LC-Ⅱ group), S 1 sacroiliac screw combined with 2 LC-Ⅱ screws (S 1+2LC-Ⅱ group), S 1 sacroiliac screw combined with 2 posterior iliac screws (S 1+2PIS group), S 1 and S 2 sacroiliac screws combined with 1 LC-Ⅱ screw (S 1+S 2+LC-Ⅱ group), S 2-alar-iliac (S 2AI) screw combined with 1 LC-Ⅱ screw (S 2AI+LC-Ⅱ group), respectively. After each internal fixation model was loaded with a force of 600 N in the standing position, the maximum displacement of the crescent fracture fragments, the maximum stress of the internal fixation (the maximum stress of the screw at the ilium fracture and the maximum stress of the screw at the sacroiliac joint), sacroiliac joint displacement, and bone stress distribution around internal fixation were observed in 5 groups. The finite element model in this study has been verified to be effective. After loading 600 N stress, there was a certain displacement of the crescent fracture of pelvis in each internal fixation model, among which the S 1+LC-Ⅱ group was the largest, the S 1+2LC-Ⅱ group and the S 1+2PIS group were the smallest. The maximum stress of the internal fixation mainly concentrated at the sacroiliac joint and the fracture line of crescent fracture. The maximum stress of the screw at the sacroiliac joint was the largest in the S 1+LC-Ⅱ group and the smallest in the S 2AI+LC-Ⅱ group. The maximum stress of the screw at the ilium fracture was the largest in the S 1+2PIS group and the smallest in the S 1+2LC-Ⅱ group. The displacement of the sacroiliac joint was the largest in the S 1+LC-Ⅱ group and the smallest in the S 1+S 2+LC-Ⅱ group. In each internal fixation model, the maximum stress around the sacroiliac screws concentrated on the contact surface between the screw and the cortical bone, the maximum stress around the screws at the iliac bone concentrated on the cancellous bone of the fracture line, and the maximum stress around the S 2AI screw concentrated on the cancellous bone on the iliac side. The maximum bone stress around the screws at the sacroiliac joint was the largest in the S 1+LC-Ⅱ group and the smallest in the S 2AI+LC-Ⅱ group. The maximum bone stress around the screws at the ilium was the largest in the S 1+2PIS group and the smallest in the S 1+LC-Ⅱ group. For the treatment of Day type Ⅱ CFDP, it is recommended to choose S 1 sacroiliac screw combined with 1 LC-Ⅱ screw for internal fixation, which can achieve a firm fixation effect without increasing the number of screws.

Cortical bone microdamage affects primary stability of orthodontic miniscrew.

The aim of this study was to investigate the effects of orthodontic miniscrew pitch and thread shape on microdamage in cortical bone. The relationship between the microdamage and primary stability was also examined. Ti6Al4V orthodontic miniscrews and 1.0-mm-thick cortical bone pieces from fresh porcine tibia were prepared. The orthodontic miniscrews had custom-made thread height (H) and pitch (P) size geometries, and were classified into three groups: control geometry; HCPC (HC; thread height=0.12 mm, PC; pitch size=0.60 mm), geometry with a narrower pitch; HCPN (HC; thread height=0.12 mm, PN; pitch size=0.30 mm), and geometry with a taller thread height; HTPC (HT; thread height=0.36 mm, PC; pitch size=0.60 mm). The orthodontic miniscrews were inserted into a pilot hole in the cortical bone, and maximum insertion torque and Periotest value were measured. After insertion, the samples were stained with basic fuchsin. Histological thin sections were obtained and the bone microdamage parameters, i.e., total crack length and total damage area, and insertion state parameters, i.e., orthodontic miniscrew surface length and bone compression area were calculated. The orthodontic miniscrews with the taller thread height resulted in lower primary stability with minimal bone compression and microdamage; however, the narrower thread pitch led to maximum bone compression and extensive bone microdamage. A wider thread pitch reduced microdamage, and decreased thread height resulted in increased bone compression, ultimately resulting in increased primary stability.

Alveolar Bone Morphologic Predictors for Guided Bone Regeneration Outcome in Anterior Maxilla

This study aimed to explore the influence of alveolar bone morphologic variables on the outcome of guided bone regeneration (GBR) in the anterior maxilla region. Twenty-eight patients who received single maxillary anterior tooth delayed implant placed simultaneously with GBR were recruited. Baseline data including age, gender, implant site, implant brand, and bone graft materials were recorded. The resorption rate of the grafted bone (RRGB), labial bone width at 0 mm, 2 mm, and 4 mm apical to the implant platform at Tn (LBW0Tn, LBW2Tn, LBW4Tn), implant angulation (IA), maximum bone graft thickness (MBGT), bone graft volume (BGV), and the initial bone morphologic variables bone concavity depth (BCD) and bone concavity angulation (BCA) were measured. The Pearson correlation analysis, analysis of variance (ANOVA), and optimal binning method were used to explore the potential predictors for GBR. Among 28 patients, the labial bone width of implant and bone graft volume decreased significantly when measured 6 months after surgery. The mean percentage of RRGB was 49.78%. RRGB was not correlated with gender, age, bone graft material, IA, MBGT, bone graft volume at T1, implant site, and implant brand (P > .05). BCD and BCA were each moderately correlated with RRGB (r=-0.872 [P < .001] and r=0.686 [P < .001], respectively). A BCD ≥1.03 mm and a BCA <155.30° resulted in a significantly lower percentage of RRGB (P < .001). A significant grafted bone materials volume reduction was detected after GBR with collagen membrane and deproteinized bovine bone mineral (DBBM). The initial bone morphology can influence GBR outcome, and a bone concavity with a depth ≥1.03 mm and an angulation <155.30° led to a lower RRGB. BCD and BCA can be used as variables to predict the outcome of GBR.

Computed Tomographic Evaluation of Buccal Shelf Dimensions in South Indian Patients With Sagittal Skeletal Class III Malocclusion: A Retrospective Study.

Background Computed tomographic evaluation of mandibular buccal shelf region in skeletal class III malocclusion cone beam computed tomography (CBCT) studies have been reported to have great alteration in the thickness of mandibular buccal shelf region owing to the different growth patterns and ethnic variations. The aim of this study was to determine the total and cortical bone thicknessin the mandibularbuccal shelf(MBS) region for extra-alveolar mini-screw placement in South Indian patients with sagittal skeletal class III malocclusion. Material and methods This retrospective computed tomographic study consisted of archived files of the Dravidian population with class III skeletal base that met the eligibility criteria. The total bone and cortical bone thickness of the buccal shelf regions were evaluated in relation to three anatomical sites at various depths and angulations. One-way ANOVA and Tukey honestly significant difference (HSD) post hoc tests were used for statistical analysis. Pearson correlation coefficient was performed to compare if any relation existed between bone thickness and the growth pattern. Results The maximum bone thickness in the buccal shelf region in our study was found at the distal portion of the second molar root, 8-12 mm from its cementoenamel junction (CEJ) and at 30-45 ° angulation (p-value<0.005). There was a positive correlation between the hypo-divergent growth pattern and the thickness of the bone. Conclusion Based on the sites recorded, the preferred site for mini screw placement in Class III patients is the distobuccal cusp region with respect to the second molarat a depth of 8-12 mmand at angulation of 30-45 °. There was a moderate correlation with hypo-divergent growth patterns, suggestive of a wider and thicker mandibular buccal shelf region in these subjects.

Virtual Three-Dimensional Model Analysis in the Assessment of the Maxillary and Mandibular Donor Sites on Cone-Beam Computed Tomography Images.

Using the Mimics software to assess the maxillary and mandibular donor sites on cone-beam computed tomography (CBCT) images. This cross-sectional study was conducted on 80 CBCT scans. Data in DICOM format were transferred to the Mimics software version 21, and a maxillary and a mandibular mask according to cortical and cancellous bones were virtually created for each patient based on Hounsfield units (HUs). Three-dimensional models were reconstructed, and boundaries of donor sites, including mandibular symphysis, ramus, coronoid process, zygomatic buttress, and maxillary tuberosity, were defined. Virtual osteotomy was conducted on the 3D models to harvest bone. The volume, thickness, width, and length of harvestable bone from each site were quantified by the software. Data were analyzed by independent t-test, one-way ANOVA, and Tukey's test (alpha = 0.05). The greatest harvestable bone volume and length differences were observed between ramus and tuberosity (P < 0.001). The maximum and minimum harvestable bone volumes were found in symphysis (1753.54 mm3) and tuberosity (84.99 mm3). The greatest difference in width and thickness was noted between the coronoid process and tuberosity (P < 0.001) and symphysis and buttress (P < 0.001), respectively. Harvestable bone volume from tuberosity, length, width, volume from symphysis, and volume and thickness from the coronoid process was significantly greater in males (P < 0.05). The harvestable bone volume was the highest in symphysis, followed by ramus, coronoid, buttress, and tuberosity. The harvestable bone length and width were the highest in the symphysis and coronoid process, respectively. Maximum harvestable bone thickness was found in symphysis.

Evaluation of the Relationship between Mandibular Third Molars and Adjacent Second Molars - Panoramic Radiography vs. CBCT

BACKGROUND&#x0D; Negative effects of third molars (3Ms) on the periodontal conditions of adjacent second molars (2Ms) depending on the level of impaction are quite common. Radiographic evaluation is of great importance in such cases. Therefore, the purpose of this study was to compare the efficacy of panoramic radiography (PR) and cone-beam CT (CBCT) images to determine the amount of bone loss on the distal side of 2Ms in relation to mandibular 3Ms.&#x0D; METHODS&#x0D; Radiographic data of 491 patients selected consecutively from the database were scanned. After applying the exclusion criteria, PR and CBCT images of a total of 97 patients were analyzed. The chi-square test was used to determine whether there was a relationship between the independent variables. The measurement of the agreement between PRs and CBCTs was calculated using Cohen's kappa coefficient.&#x0D; RESULTS&#x0D; 97 patients (47 females and 50 males) aged between 18-67 years (33.79±12.23 years) were included in this study. Most of the patients were in their 20s (41.2%). Moderate agreement was found between measurements made using PR and CBCT to determine bone loss in the distal side of the 2M. While bone loss was recorded in 53.7% of the teeth as a result of measurements made with PRs, this prevalence was determined as 61.5% in measurements made with CBCTs. (κ=0.448; P&lt;0.001). There was no difference in terms of bone loss according to gender and location, while the highest rate of bone loss was observed in individuals aged 50 and over. In addition, a maximum bone loss was detected when 3M's position was horizontal and Class III / Level C according to Winter and Pell &amp; Gregory classifications, respectively.&#x0D; CONCLUSIONS&#x0D; In individuals with 3M teeth, it is critical to use radiographs at regular intervals to monitor the periodontal status of 2M teeth, even in the absence of symptoms. In cases where severe bone loss is observed or suspected to be severe, CBCT provides detailed information and facilitates the clinician in planning any intervention.

3D MRI PD‐SPACE‐COR Predicting Safety Margin for Coracoid Transfer

The maximum bone length available for coracoid process transfer varies among individuals, while no preoperative guideline has been developed for predicting the safety margin (SM) in Latarjet shoulder reconstruction. The aim of the study was to evaluate the 3D MRI proton density (PD)-weighted sampling perfection with application-optimized contrasts using different flip-angle evolution (SPACE) sequence in preoperatively predicting SM for coracoid transfer. The post-multiplanar reconstructed images were obtained from 24 volunteers (17 males, seven females) to determine the clarity and sensitivity of the PD-SPACE-COR and PD-SPACE-FS-COR protocols. Furthermore, the distance from the coracoid tip to the lateral edge of the attachment of trapezoid ligament (TL) was measured. To evaluate the accuracy of 3D MRI prediction, a cadaveric cohort has been launched in 32 shoulders (nine males, seven females). The distance between the tip of coracoid process and the outmost edge of TL footprint, namely, the SM, was measured. A better sensitivity was found in PD-SPACE-COR in detecting coracoclavicular ligaments (CCLs), including TL and conoid ligament (CL), compared to PD-SPACE-FS-COR by ranking, McNemar test (P= 0.001), and kappa coefficients (κ=0.51, P= 0.43). The SM determined by the PD-SPACE-COR protocol was 24.28 ± 2.17 mm while that by cadaveric morphometry was 25.53 ± 2.84 mm. No difference was found between measurements (P= 0.78). This research provides new insights for preoperatively geometrical planning coracoid transfer by 3D MRI PD-SPACE-COR, which motivates personalized medicine in orthopedics.

Effects of PTH glandular and external dosing patterns on bone cell activity using a two-state receptor model-Implications for bone disease progression and treatment.

Temporal aspects of ligand specificity have been shown to play a significant role in the case of pulsatile hormone secretion, as exemplified by parathyroid hormone (PTH) binding to its receptor (PTH1R), a G-protein-coupled receptor expressed on surfaces of osteoblasts and osteocytes. The latter binding reaction regulates intracellular signalling and subsequently modulates skeletal homeostasis via bone remodelling. PTH glandular secretion patterns dictate bone cellular activity. In healthy humans, 70% of PTH is secreted in a tonic fashion, whereas 30% is secreted in low-amplitude and high-frequency bursts occurring every 10-20 min, superimposed on the tonic secretion. Changes in the PTH secretion patterns have been associated with various bone diseases. In this paper, we analyse PTH glandular secretion patterns for healthy and pathological states and their link to bone cellular responsiveness (αR). We utilise a two-state receptor ligand binding model of PTH to PTH1R together with a cellular activity function which is able to distinguish various aspects of the stimulation signal including peak dose, time of ligand exposure, and exposure period. Formulating and solving several constrained optimisation problems, we investigate the potential of pharmacological manipulation of the diseased glandular secretion and via clinical approved external PTH injections to restore healthy bone cellular responsiveness. Based on the mean experimentally reported data, our simulation results indicate cellular responsiveness in healthy subjects is sensitive to the tonic baseline stimulus and it is 28% of the computed maximum responsiveness. Simulation results for pathological cases of glucocorticoid-induced osteoporosis, hyperparathyroidism, initial and steady state hypocalcemia clamp tests indicate αR values significantly larger than the healthy baseline (1.7, 2.2, 4.9 and 1.9-times, respectively). Manipulation of the pulsatile glandular secretion pattern, while keeping the mean PTH concentration constant, allowed restoration of healthy baseline values from these catabolic bone diseases. Conversely, PTH glandular diseases that led to maximum bone cellular responsiveness below the healthy baseline value can't be restored to baseline via glandular manipulation. However, external PTH injections allowed restoration of these latter cases.

Dosimetric Comparison of Different Radionuclides Used in Metastatic Bone Disease Treatment.

This study aimed to determine the critical organ doses in 223Ra, 89Sr, 153Sm, and 32P treatments via dosimetry using the phantoms. The OpenDose was used to calculate S values (mGy MBq-1s-1) for bone surface, red bone marrow, urinary bladder wall, testes, ovaries, uterus, and kidneys using male (ICRP110AM) and female (ICRP110AF) phantoms. The cortical thoracic spine was modeled as metastasis. Moreover, the absorbed doses were computed via MIRD formalism according to the activities of 3.3, 148, 2220, and 370 MBq for ICRP110AM and 4.015, 148, 2701, and 370 MBq for ICRP110AF in 223Ra, 89Sr, 153Sm, and 32P treatments, respectively. Whilst the maximum bone surface doses were found as 1.22E+02 and 8.51E+01 mGy at 32P treatment, the minimum bone surface doses were calculated as 8.42E-02 and 8.26E-02 mGy at 223Ra. In terms of the comparison of red bone marrow, urinary bladder wall, and kidney doses, 153Sm and 89Sr treatments showed maximum doses of 2.45E-03, 1.50E-03, 3.23E-07, 5.45E-06, 1.20E-01, 1.49E-01 mGy and the minimum doses with 3.46E-05, 1.99E-05, 6.33E-09, 8.77E-09, 1.19E-04, 1.15E-04 mGy, respectively. The maximum testes and ovaries-uterus doses were found as 6.17E-08, 7.40E-06, 3.46E-07 mGy in 153Sm treatment, and minimum testes and ovaries doses as 1.70E-09, 1.34E-07 mGy in 223Ra. The minimum uterus dose with 7.03E-09 mGy was determined in 89Sr treatment. It is observed that 223Ra produces low critical organ doses in the treatment of painful bone metastasis. Among the beta-emitting radionuclides, 89Sr stands out by showing optimal dosimetric results.

ОСНОВИ БІОМЕХАНІЧНОГО АНАЛІЗУ ЗУБНИХ ІМПЛАНТАТІВ З МИТТЄВИМ НАВАНТАЖЕННЯМ

Success of immediately loaded dental implant can be achieved by selecting appropriate implant dimensions through establishing their correlation with interfacial strains which are responsible for bone healing and osseointegration process. This study aim was to correlate maximal bone strains induced by variable-sized implants with functional loads for the purpose of their comparing with mean experimental functional load. 3D models of 24 implant-bone assemblies were designed and finite element analysis was performed in ANSYS 15. Maximal first principal strains were analyzed. Current ultimate functional load values, corresponding to 3000 μstrain of pathological bone turnover, were determined and compared with 120.92 N mean experimental functional load to evaluate the success prognosis. Strains were found directly dependent on bone quality and implant dimensions. So, bone strains alone have an impact on immediate loading success. It is favorable for tested implants placed in type III bone, if functional load does not exceed 120.92 N. Type IV bone is completely unacceptable for immediate loading

Development of a Colorimetric Scale as an Aid for Estimating Temperature of Burnt Bone

Background: Forensic pathologists, archeologists, and forensic anthropologists are often required to interpret burnt bones. One of the key factors for an accurate interpretation of the remains and the events leading to incineration is the estimation of the maximum exposure temperature of the human remains. Several types of research focus on temperature estimation, using color assessment, histology observations, and mechanical changes, which can help in the most accurate interpretation. The color of burnt bone is inevitably related to the time and temperature(s) to which it was exposed, the size and condition of the bone, and the environment. Nevertheless, it can be possible to estimate exposure temperature based on visual observation and analysis. Objective: Development of a colorimetric scale for photographic documentation and the color calibration of burnt bone. Method: This paper proposes a patented prototype scale with calibrated colors of burnt bone colors at different temperatures, based on the existing RGB color published data as a visual aid in the interpretation and estimation of the maximum temperature exposure of burnt bone. Results and Discussion: Authors are aware that the estimation of the maximum temperature of burnt bone cannot be determined solely by colors. Visual color recognition is prone to errors. Conclusion: The proposed device should be considered a tool during photography of burnt bone and aid in interpreting temperature estimates.

How Many Generations are Available for Study? Expectations and Applications of Historical Ecological Insight from Bones Lying on Modern Landscapes

Skeletal remains lying on landscape surfaces are useful for evaluating historical states of living populations, but across how much time can such resources inform management and conservation? Further, how do differences in environmental setting impact the breadth of the available timeseries? Using radiocarbon dated bones from across the globe, we evaluated the relationship between the maximum duration that bones persist on landscapes and the mean annual temperature of each locality. We found that bones can persist for several millennia in cold (high-latitude) settings and that there is a strong link (R2 &gt; 0.9, p &lt; 0.01) between local temperature and the logged duration of maximum bone persistence. This relationship provides an initial expectation for the duration across which skeletal remains from different settings can provide historical ecological context. Across the Holarctic, caribou (Rangifer tarandus) are the most abundant large mammal and arguably the most economically significant one for multiple human cultures, including serving as a key nutritional and cultural resource. For migratory caribou, movements between winter ranges and spring calving grounds are among the longest annual migrations of any terrestrial species and maintaining access to these areas is a top conservation priority. But how long have herds used particular calving grounds? Shed female antlers lying on the tundra provide insight into historical calving geography because they are shed within days of giving birth. Following antler surveys across the Coastal Plain calving grounds (Arctic National Wildlife Refuge, Alaska) of the Porcupine Caribou Herd (PCH), we radiocarbon dated three highly weathered female antlers. Antler ages ranged between ~1,600 and &gt;3,000 calendar years ago. These antlers provide the first physical evidence of calving activity on the PCH calving grounds from previous millennia and substantiate the long ecological legacy of the Coastal Plain as a caribou calving ground.

Differences in clinical and radiographic features between bilateral and unilateral adult degenerative temporomandibular joint disease: A retrospective cross-sectional study

To study the correlations of clinical findings and the severity of osseous alterations between bilateral and unilateral degenerative joint disease (DJD) of the temporomandibular joint (TMJ). Forty-eight joints from 35 adult patients with DJD were retrospectively examined. The joints were divided into two groups: bilateral DJD (BDJD) (26 joints) and unilateral DJD (UDJD) (22 joints). We collected data on patient characteristics and symptoms, including pain on palpation, limited mouth opening, pain during mandibular movement, and joint noises. Cone beam Computed Tomography (CBCT) was used to assess bony changes, including maximum condylar bone change, severity of erosion, severity of osteophytes, glenoid fossa changes, and superior joint space measurements. Data were correlated between subgroups. There was no significant difference between the two groups in terms of age or gender. However, pain on palpation was significantly more common in UDJD joints (81.8%) compared to BDJD joints (53.9%). Limitation of mouth opening was also significantly more common in BDJD cases (61.5%) compared to UDJD cases (22.7%). The number of joints with painless degeneration was more common in BDJD TMJs (38.4%) than in UDJD TMJs (9%). There was no significant difference between the two subgroups with regard to pain during mandibular movements or joint sounds and severity of bony changes. This study provided important results outlining clinical the clinical profiles of DJD patients. While painful degeneration was more frequent in UDJD joints, painless degeneration was higher in BDJD joints. Limitation of mouth opening was more common in BDJD patients.

Thermomechanical damage in cortical bone caused by margins of surgical drill bit: A finite element analysis

Background and ObjectiveConventional surgical drill bits suffer from several drawbacks, including extreme heat generation, breakage, jam, and undesired breakthrough. Understanding the impacts of drill margin on bone damage can provide insights that lay the foundation for improvement in the existing surgical drill bit. However, research on drill margins in bone drilling is lacking. This work assesses the influences of margin height and width on thermomechanical damage in bone drilling. MethodsThermomechanical damage—maximum bone temperature, osteonecrosis diameter, osteonecrosis depth, maximum thrust force, and torque—were calculated using the finite element method under various margin heights (0.05-0.25 mm) and widths (0.02-0.26 mm). The simulation results were validated with experimental tests and previous research data. Results: The effect of margin height in increasing the maximum bone temperature, osteonecrosis diameter, and depth were at least 19.1%, 41.9%, and 59.6%, respectively. The thrust force and torque are highly sensitive to margin height. A higher margin height (0.21-0.25 mm) reduced the thrust force by 54.0% but increased drilling torque by 142.2%. The bone temperature, osteonecrosis diameter, and depth were 16.5%, 56.5%, and 81.4% lower, respectively, with increasing margin width. The minimum thrust force (11.1 N) and torque (41.9 Nmm) were produced with the highest margin width (0.26 mm). The margin height of 0.05-0.13 mm and a margin width of 0.22-0.26 produced the highest sum of weightage. ConclusionsA surgical drill bit with a margin height of 0.05-0.13 mm and a margin width of 0.22-0.26 mm can produce minimum thermomechanical damage in cortical bone drilling. The insights regarding the suitable ranges for margin height and width from this study could be adopted in future research devoted to optimizing the margin of the existing surgical drill bit.

Usefulness of quantitative bone SPECT/CT for evaluating medication-related osteonecrosis of the jaw treatment response.

For assessment of therapeutic response in medication-related osteonecrosis of the jaw (MRONJ) cases, the clinical usefulness of quantitative bone single-photon computed tomography-computed tomography (SPECT/CT) results was investigated. Sixteen patients (18 lesions) with a clinical diagnosis of MRONJ underwent bone SPECT/CT scanning before and during/after anti-inflammatory therapy given for 3 or more months. The GI-BONE software package was used to determine standard uptake values (SUVs), including maximum (SUVmax), peak (SUVpeak), and mean (SUVmean), and metabolic bone volume (MBV) and also total bone uptake (TBU). In both responders (downstage) and non-responders (upstage or no change), differences in quantitative values between the first and second SPECT/CT examinations were analyzed using a Wilcoxon test. Following therapy, significant reductions in SUVmax, SUVpeak, SUVmean, MBV and TBU values for 11 lesions were noted in the responders after therapy (p = 0.003, p = 0.006, p = 0.004, p = 0.003, and p = 0.002, respectively). On the other hand, those for the seven lesions in the non-responder group were not significantly different (p = 0.17, p = 0.16, p = 0.26, p = 0.96, and p = 0.12, respectively). Results for SUVmax change showed sensitivity and specificity values of 45.5% and 85.7%, respectively, for differentiating responders from non-responders, with -37.3% the optimal cutoff value. Those for MBV change were 72.7 and 85.7%, respectively, with -29.4% the optimal cutoff value. Those for TBU change were 81.8% and 85.7%, respectively, with -36.3% the optimal cutoff value. The present findings showed that therapeutic response in MRONJ cases could be determined by use of quantitative SUV, MBV, and TBU values based on bone SPECT/CT findings.

Intake and growth histories modulate bone morphology, microarchitecture, and mineralization in juvenile green turtles (Chelonia mydas)

Abstract Compensatory growth (CG) is accelerated growth that occurs when food availability increases after food restriction. This rapid growth may be associated with sublethal consequences. In this study, we investigated the effects of food restriction and subsequent realimentation and CG on bone structure in juvenile green turtles (Chelonia mydas). Turtles were fed ad libitum food for 12 weeks (AL), restricted food for 12 weeks (R), or restricted food for 5 weeks followed by ad libitum food for 7 weeks (R-AL). R-AL turtles demonstrated partial CG via enhanced food conversion efficiency (FCE) upon realimentation. After the 12th week, gross morphology (GM), microarchitecture, and mineralization of the right humerus of each turtle were analyzed. Many GM measurements (including proximal and maximal bone lengths, bone widths, and shaft thickness), most measurements of bone microarchitecture (excluding cortical and trabecular thickness and trabecular separation), and all mineralization measurements were labile in response to intake. We examined the possibility that changes in nutrient allocation to bone structure during realimentation facilitated CG in previously food-restricted turtles. Restoration of bone lengths was prioritized over restoration of bone widths during CG. Furthermore, restoration of trabecular number, connectivity density, and bone volume fraction was prioritized over restoration of cortical bone volume fraction. Finally, diaphyseal bone mineralization was partially restored, whereas no restoration of epiphyseal bone mineralization occurred during CG. Shifts in nutrient allocation away from certain bone attributes during food restriction that were not rectified when food availability increased probably provided an energy surplus that enhanced the conversion of food to growth and thus powered the CG response. Our study revealed how resource allocation to various bone attributes is prioritized as nutritional conditions change during development. These “priority rules” may have detrimental consequences later in life, indicating that conservation of green turtle foraging grounds should be given high priority.