Amount Of Bone Research Articles

Bone turnover, areal BMD, and bone microarchitecture by second-generation high-resolution peripheral quantitative computed tomography in transfusion-dependent thalassemia.

Thalassemic osteopathy includes low bone mass and impaired bone microarchitecture. We aimed to evaluate the prevalence and determinants of bone quantity (osteoporosis) and quality (microarchitecture) in a cohort of adult patients with transfusion-dependent thalassemia (TDT). Patients with TDT (n = 63) and age- and BMI-matched controls (n = 63) were recruited in the study. Areal bone mineral density (BMD) was measured using DXA Hologic scanner. P1NP and β-CTX were estimated by electrochemiluminescence assay. Bone geometry and volumetric BMD (vBMD) were estimated by second-generation high-resolution peripheral quantitative computed tomography. Bone turnover marker β-CTX was significantly lower in the TDT group, but there was no difference in P1NP levels. Low bone mass (Z ≤ -2) was present in greater proportion of patients both at lumbar spine (LS) (54 vs 0%; p = .001) and femoral neck (FN) (33 vs 8%; p = .001). Hypogonadism was associated with low BMD at FN (OR 10.0; 95% CI, 1.2-86; p = .01) and low hemoglobin with low BMD at LS (OR 1.58; 95% CI, 0.96-2.60; p = .07). The mean trabecular bone score was also significantly lower in patients compared with controls (1.261 ± 0.072 vs 1.389 ± 0.058). Total, cortical and trabecular vBMD were significantly lower in cases than controls. The trabecular number and cortical thickness were significantly lower and trabecular separation higher in cases than controls. Adults with TDT have significantly lower areal, cortical and trabecular vBMD. The bone microarchitecture is also significantly impaired in terms of lower number and wider spacing of trabeculae as well as lower cortical thickness and area at both radius and tibia.

Crestal approach for maxillary sinus augmentation in individuals with limited alveolar bone height: An observational study.

In cases where the bone presence is <4 mm, the lateral approach is typically the first approach considered. Nevertheless, for patients who prefer minimally invasive procedures or wish to reduce postoperative discomfort, the crestal approach is a viable option. The objective of this study was to investigate the potential of crestal sinus augmentation for achieving adequate bone in individuals with residual bone measuring <3 mm. The study comprised 11 participants (63.6 ± 10.9 years of age) who were treated at Seoul St. Mary's Hospital between 2021 and 2023 and received crestal approach sinus augmentation due to insufficient bone density of <3 mm using the crestal approach kit. Pre-augmentation and post-augmentation cone-beam computed tomographic images were analyzed using the imaging software to measure vertical bone height, bucco-palatal width, and mesio-distal width. Before the intervention, the height of the vertical bone was 2.1 ± 0.5 mm, while the width from buccal to palatal was 10.6 ± 2.9 mm, and the width from mesial to distal was 9.9 ± 1.2 mm. Following the intervention, these measurements increased to 8.8 ± 0.9 mm, 12.2 ± 2.2 mm, and 10.2 ± 1.2 mm, respectively. The change in height of the vertical bone was 6.7 ± 1.0 mm, in bucco-palatal width was 1.6 ± 1.4 mm, and in mesio-distal width was 0.3 ± 0.4 mm. The results revealed a significant rise in the height of the vertical bone and bucco-palatal width. Crestal sinus augmentation has been demonstrated to be a highly effective approach for achieving an adequate quantity of bone in patients with residual bone <3 mm. Nonetheless, further observation is required to evaluate the long-term prognosis of the procedures.

A proposal for the combined analysis of bone quantity and quality of human cortical bone by quasi-brittle fracture mechanics

Quasi-brittle fracture mechanics is used to evaluate fracture of human cortical bone in aging. The approach is demonstrated using cortical bone bars extracted from one 92-year-old human male cadaver. In-situ fracture mechanics experiments in a 3D X-ray microscope are conducted. The evolution of the fracture process zone is documented. Fully developed fracture process zone lengths at peak load are found to span about three osteon diameters. Crack deflection and arrest at cement lines is a key process to build extrinsic toughness. Strength and toughness are found as size-dependent, not only for laboratory-scale experimental specimens but also for the whole femur. A scaling law for the length fracture process zone is used. Then, size-independent, tissue fracture properties are calculated. Linear elastic fracture mechanics applied to laboratory beam specimens underestimates the tissue toughness by 60%. Tissue fracture properties are used to predict the load capacity of the femur in bending within the range of documented data. The quasi-brittle fracture mechanics approach allows for the assessment of the combined effect of bone quantity and bone quality on fracture risk. However, further work is needed considering a larger range of subjects and in the model validation at the organ length scale.

Caloric Restriction Diet Attenuates Systemic Bone Fragility after Radiotherapy

Bone fragility is a well-documented long-term side effect of radiotherapy, which currently has no preventative treatments. In this study, we applied a caloric restriction (CR) diet to attenuate both local and systemic bone loss after irradiation (RTx) in an established female Balb/c mouse model (4 consecutive daily doses of 5 Gy to the right hindlimb only). CR mice were tapered down to a 30% reduced calorie diet (RTx/CR) one week before irradiation, while regular diet (RD) mice received food ad libitum (RTx/RD). Unirradiated (sham) mice received either a 30% CR diet (SH/CR) or received food ad libitum (SH/RD). Irradiated, contralateral, and unirradiated hindlimbs were evaluated at 2, 4, and 8 weeks postirradiation using micro-computed tomography (μCT) to assess bone morphology and 3-point bending to quantify femur strength. Histological analysis of irradiated and unirradiated tibiae was performed to examine general bone tissue cytology and serum biomarker analysis was performed using terminal blood draw samples. After treatment, femur strength and metaphyseal bone quantity was decreased in irradiated and contralateral femora of RTx/RD mice compared to SH/RD femurs; this finding is consistent with previous studies. RTx/CR mice had positive effects when compared to RTx/RD mice, including increased strength relative to body mass in both the irradiated and contralateral limb, increased trabecular bone mass, and decreased marrow adiposity. However, a number of adverse effects were also observed, including a significant decrease in body mass and decreased cortical bone. Overall, CR shows promise as a preventative treatment for postirradiated bone fragility, yet questions remain to be addressed in future studies. Ideal diet duration, impact to normal tissue, and mechanism of action must be explored to better understand the clinical implication of a CR diet.

Bone Preservation in Femoral Intercondylar Box Cut - A Comparative Study between Older and Newer Generation Implants.

This study was conducted to compare the quantity of intercondylar bone removed during femoral box osteotomy for implantation of three contemporary newer generation posterior stabilized (PS) total knee arthroplasty designs Attune PS (DePuy), Anthem (Smith and Nephews), and NexGen Legacy (Zimmer) with the older version from the same manufacturers. We compared the maximum volumetric bone resection required for the housing of the PS mechanism of these six designs. Bone removal by each PS box cutting jig was three-dimensionally measured. The differences between the three designs were analyzed by the Kruskal-Wallis test. The Mann-Whitney U-test was used for pairwise comparisons. The level of significance was set at P < 0.05. The newer generation implants save approximately 33% of bone that was resected from the box cut as compared to the older versions. DePuys Attune PS saved 27.1% bone as compared to Sigma PS resecting 6.96 cm3 of bone, and Zimmers Persona saved 40.57% bone as compared to NexGen from the intercondylar box cut resecting 6.18 cm3. Smith and Nephew s Anthem and Genesis have no difference in their box volume with both resecting 7.8 cm3 of bone. Irrespective of implant size, the Attune PS (DePuy) and Nexgen Legacy (Zimmer) cutting jigs always resected significantly less bone than did the jigs of older generations. There was no significant difference in the bone removed during femoral box osteotomy in the newer and older generations of Smith and Nephew.

Simulation of depth-dose curves and water equivalent ratios of energetic proton beams in cortical bone.

We have determined the depth-dose curve, penetration range, and water equivalent ratio for proton beams of clinical energies in cortical bone by means of a detailed and accurate simulation that combines molecular dynamics and Monte Carlo techniques. The fundamental input quantities (stopping power and energy loss straggling) for the simulation were obtained from a reliable electronic excitation spectrum of the condensed-phase target, which takes into account the organic and mineral phases that form it. Our simulations with these inputs, which are in excellent agreement with the scarce data available for a cortical bone target, deviate from simulations performed using other stopping quantities, such as those provided by the International Commission on Radiation Units and Measurements in its widely used Report No. 49 [M. J. Berger et al., Stopping powers and ranges for protons and alpha particles, International Commission on Radiation Units and Measurements, Bethesda, Maryland, 1993]. The results of this paper emphasize the importance of an accurate determination of the stopping quantities of cortical bone to advance towards the millimetric precision for the proton penetration ranges and deposited dose needed in radiotherapy.

Carbonate Apatite Honeycomb Scaffold-Based Drug Delivery System for Repairing Osteoporotic Bone Defects.

Osteoporotic bone defects are difficult to repair in elderly patients. This study aimed to repair osteoporotic bone defects using a combination of bone tissue engineering (BTE) and drug delivery systems (DDS). Herein, honeycomb granules (HCGs) composed of carbonate apatite microspheres were fabricated as BTE scaffolds. Each HCG possesses hexagonal macropores and abundant interconnected micropores between the microspheres. Owing to these multiscale interconnected pores, HCGs can readily contain antibodies against sclerostin (Scl), which causes imbalances in bone homeostasis. Anti-Scl antibody-loaded HCGs (Scl-Ab-HCGs) regulate the release of Scl-Abs in response to the pH of the osteoporotic environment. In ovariectomized rabbit osteoporotic femurs, HCG monotherapy forms new bone with less osteocyte damage (fewer empty bone lacunae) and fewer osteoclasts than osteoporotic bone; however, it is insufficient to prevent receptor activator of nuclear factor-kappa B ligand (RANKL) overexpression. Consequently, HCG monotherapy restores bone quantity better than no treatment but not to normal levels. In contrast, new bone tissue formed by Scl-Ab-HCG-based DDS predominantly expresses osteocalcin rather than RANKL, similar to normal bone, and shows a similar osteocyte apoptosis level, bone quantity, and osteoclast number as normal bone. Thus, Scl-Ab-HCG-based DDS is a promising approach for osteoporotic bone defect repair.

The Value of Mandibular Indices on Cone Beam Computed Tomography in Secondary Causes of Low Bone Mass.

Background: As implant treatment cases increase, many cases of failure/side effects also occur. Generally, dental clinics determine the density of the jawbone using cone beam CT (CBCT). Considering the known potential role of this tool for bone assessment in primary osteoporosis, this study evaluated patients with secondary endocrine causes of low bone mass. Methods: The study included 83 patients with endocrine causes of osteoporosis who were evaluated by dual-energy X-ray absorptiometry (DXA), trabecular bone score (TBS), and mental foramen (MF) region CBCT. The following CBCT indices were measured: anterior (A)-thickness of inferior mandibular cortex 10 mm anterior from MF; molar (M)-thickness of inferior mandibular cortex 10 mm posterior from MF; posterior (P)-thickness of inferior mandibular cortex 25 mm posterior from MF; symphysis (S)-thickness of inferior mandibular cortex equidistant from the centers of right and left MF. Results: The highest correlation coefficient in the secondary causes group was between the A index and the lumbar BMD (r = 0.375, p = 0.001) and the P index and the femoral neck BMD (r = 0.38, p = 0.001). Hypercortisolism seems to be the most predictable cause of secondary osteoporosis using the A, M, and P indices. The A, M, and P indices showed predictive values of the bone micro-architecture that was evaluated using TBS score, and were statistically significant. The symphysis index does not significantly predict osteoporosis or impaired bone micro-architecture. Conclusions: These findings support the potential usefulness of A, M, and P CBCT-derived radiomorphometric mandibular indices in secondary osteoporosis, underlining the well-known effects of these pathologies on bone micro-architecture rather than bone quantity.

Cone Beam Computed Tomography Panoramic Mandibular Indices in the Screening of Postmenopausal Women with Low Bone Mass: Correlations with Bone Quantity and Quality.

This study examined the potential use of computed tomography panoramic mandibular indices on cone beam CT (CBCT) for assessing bone density in postmenopausal women with low bone mass. The study enrolled 104 postmenopausal women who underwent dual-energy X-ray absorptiometry (DXA) using a DXA scanner and mental foramen region CBCT alongside the NewTom VGi EVO Cone Beam 3D system. We assessed the relationship between the following DXA parameters: lumbar, femoral neck, and total hip T score, bone mineral density (BMD), and lumbar trabecular bone score (TBS). The following panoramic mandibular indices were also considered: the computed tomography mandibular index superior (CTI(S)), computed tomography mandibular index inferior (CTI(I)), and computed tomography mental index (CTMI). The study revealed moderate correlations between CBCT indices and BMD/TBS scores: CTMI showed the highest correlation with the femoral neck T-score (r = 0.551, p < 0.0001). TBS scores were also moderately correlated with CBCT indices: CTMI showed a moderate positive correlation with TBS (r = 0.431, p < 0.0001); CTI(S) had a similar moderate positive correlation with TBS (r = 0.421, p < 0.0001). AUC values ranged from 0.697 to 0.733 for osteoporosis versus the osteopenia/normal group and from 0.734 to 0.744 for low versus normal bone quality groups, p < 0.0001. The comparison of the values of the studied indices between low versus normal bone quality (quantified with TBS) groups showed high sensitivity but low specificity. CBCT-measured indices CTI(S), CTI(I), and CTMI are useful in assessing patients with low bone mass to improve, by specific treatment, the prognosis of dental implants.

Comparative Evaluation of Primary Stability in Truncated Cone Implants with Different Macro-Geometries in Low-Density Polyurethane Blocks Simulating Maxillary Sinus Rehabilitations

After tooth loss, particularly in the posterior maxilla, the alveolar ridges undergo bone resorption. Therefore, ensuring the appropriate quantity and quality of alveolar bone is crucial for accurate implant positioning and achieving optimal esthetic and functional results. This study aimed to evaluate biomechanical parameters (insertion torque: IT, removal torque: RT, and implant stability quotient: ISQ) of distinct truncated cone implant designs (Sinus-plant and SLC) on polyurethane blocks simulating type D3 and D4 bone. SLC implants exhibited significantly higher IT, RT, and ISQ values compared to Sinus-plant implants, except in the 10 pounds per cubic foot (PCF) density block with a cortical layer for the IT (24.01 ± 0.91 vs. 23.89 ± 1.66 Ncm). The IT values for SLC implants ranged from 13.95 ± 0.19 Ncm in the lowest density block to 37.94 ± 0.45 Ncm in the highest density block, consistently providing significantly higher primary stability with an ISQ of approximately 70 in the highest density block. Despite lower ISQ in the lowest density block (48.60 ± 0.52 and 48.80 ± 0.42 in buccolingual and mesiodistal directions), it was deemed acceptable considering the inadequate bone densities in the maxillary region. These findings on SLC suggest potential clinical advantages, including reduced procedure duration and costs, improved stability, and the possibility of immediate implant placement following sinus augmentation, thereby streamlining the rehabilitation process.

Importance of local and systemic factors in preventing implant displacement in the mandibular body: a scoping review of existing literature

BackgroundThe aim of this research was to analyse the current literature on displaced dental implants in the mandibular body, including local and systemic variables related to their cause, and to identify the most frequent location.MethodsThe study conducted a search of three databases (Pubmed, Scopus, and Web of Science) using specific index terms such as ‘dental implant’, ‘displacement’, ‘dislocation’, ‘displaced’, and ‘mandible’. The analysis focused on the direction of displacement and the characteristics of the bone tissue (bone quality, density, and quantity) in cases where dental implants were displaced.ResultsA total of 371 articles were obtained. Thirteen of these articles were selected and read in full. To define bone quality, the Lekholm and Zarb classification, modified by Rosas et al., was used. The type II-B bone, which is characterized by thick cortical bone surrounding cancellous bone with extremely wide medullary spaces, presented the largest number of complications. Twenty-two cases were found in which the displacement direction was horizontal. Of these, four were displaced vestibularly, fourteen lingually, and four remained in the center. Additionally, 24 cases presented vertical displacement, with 12 displaced towards the inferior border of the mandible, 9 towards the middle or adjacent to the inferior dental nerve canal, and 3 above the inferior dental nerve canal.ConclusionThe accidental displacement of implants within the mandibular body is associated with various risk factors, including the characteristics of the bony trabeculum and the size of the medullary spaces. It is reasonable to suggest that only an adequate pre-surgical diagnostic evaluation, with the help of high-resolution tomographic images that allow a previous evaluation of these structures, will help to have better control over the other factors, thus minimizing the risk of displacement.

Prosthodontic criteria for maxillary immediate occlusal loading, surgical classifications of atrophic maxillae, and presentation of a new implant/anatomic classification system for immediate maxillary rehabilitation.

Immediate full-arch occlusal loading for patients with atrophic edentulous maxillae satisfies critical needs for this specific type of edentulous patient after placement of implants with high levels of primary implant stability. The needs include improved aesthetics, limited immediate improved function, and elimination of removable prostheses. Classification systems exist for edentulous maxillae but they do not include specifics regarding posterior implant placement. In conjunction with anterior implants, posterior implants improve Anterior/Posterior (A/P) spreads, decrease cantilevered segments (CLs), and likely will improve implant and prosthetic success rates. The purposes of this article include presenting a new classification system that outlines the different types of implants now available which will likely achieve the requisite primary stability for immediate fixed rehabilitation. This proposed classification system identifies a relationship between different implant options currently available and the remaining quantity of bone in the first and second maxillary molar zones. The available literature regarding current classification systems was reviewed. The benefits and limitations of each system were described. The parameters associated with Immediate Occlusal Loading (IOL) for full arch maxillary prostheses include: posterior cantilever lengths of full arch fixed prostheses; existing A/P spread considerations for full arch prostheses; and introduction of a new classification system for atrophic posterior maxillary edentulous ridges were identified. Currently, there are no available classification systems that outline specific implant options for posterior maxillae which will likely achieve the minimum primary stability needed for immediate rehabilitation. A new classification system was proposed where the rationale was to show clinicians that when a certain amount of bone remains in the posterior maxilla, there are specific implants designed to maximize primary stability. High implant primary stability is required for rehabilitation with immediate fixed implant-supported provisional prostheses. The proposed classification system assists clinicians in understanding what implant geometry is available and can be expected to achieve the requisite primary stability for immediate occlusal loading based on the available bone in the posterior maxillary molar zone. This article reviewed current classification systems for edentulous maxillary patients, as well as clinical parameters required for full arch, immediate occlusal loading. It also presented a new classification system to assist clinicians in selecting appropriate implants and surgical techniques for immediate fixed rehabilitation of patients with atrophic maxillae.

Evaluation of the Long-Term Success and Patient-Related Outcomes of Zygomatic Implants in Atrophic Maxillary Ridges.

Introduction Zygomatic implants (ZIs) have emerged as a promising option for rehabilitating completely edentulous patients with severe maxillary atrophy. These implants anchor into the zygomatic bone, bypassing the need for extensive grafting procedures. Success rates in dental and craniofacial implant surgeries can be influenced by several surgical factors, including suture techniques, flap design, and treatment planning. The research aimed to present the clinical outcomes and complications in individuals with severely resorbed maxillae who underwent prosthodontic rehabilitation using the Quad Zygoma Protocol (QZP) and the Anatomy-Guided Approach (AGA), focusing on long-term assessment. Material and methods Data for this retrospective study were extracted from the institution's patient database, involving a meticulous review of patient records. This comprehensive examination encompassed demographic data, preoperative assessments, details of surgical procedures, postoperative complications, and subsequent follow-up evaluations. Patients with severe maxillary bone deficiencies resulting in complete edentulism, due to inadequate bone quality and quantity in both anterior and posterior regions, were selected for inclusion. Exclusion criteria were applied to individuals with incomplete records or insufficient follow-up data, as well as those who underwent alternative treatment modalities or presented with comorbidities potentially impacting implant outcomes. The selected patients underwent treatment utilizing the QZP, with each participant subjected to a minimum three-year follow-up period. The implant survival rate, prosthetic success, complications, and Oral Health-Related Quality of Life using the OHIP-14 questionnaire were assessed. Results At the end of the follow-up period involving 12 patients (eight men, four women) with 43 ZIs - 37 from Neodent, four from Nobel Biocare, and two from Norris - with a mean duration of 4.3 years (range: 1.2-5.4), the overall success rate stood at 99.08%, with only 1 out of 42 implants failing. All patients received immediate loading with an acrylic prosthesis, proving effective in 98.2% of cases. The most common issues observed were localized soft tissue inflammation (35.7%) and sinus inflammation (12.5%), occurring after mean follow-up periods of 1.2 and 3.5 years, respectively. In 12 patients, the mean score of the OHIP-14 questionnaire was 1.6 ± 2.6, with a follow-up period of 5 ± 0.6 years. Conclusion The QZP has consistently demonstrated excellent long-term success in restoring severely reduced maxillary structures. An immediate loading approach could aid in stabilizing ZIs through cross-arch support.

Transalveolar sinus lifting using autogenous chin graft containing implant in atrophic posterior maxillary alveolar ridge

Abstract Background Posterior maxillary implant rehabilitation is a critical procedure because of the diminished bone quality and quantity, especially in severe atrophic posterior maxilla which affect the stability of the implant and raises the demand of the sinus floor elevation, bone augmentation and ensuring implant stability in order for the implant to succeed. Transalveolar sinus lifting is a valuable technique in reaching and augmenting the floor of the sinus without penetrating the sinus membrane or causing sinusitis and to avoid numerous surgical interventions. Patients and methods This is a prospective, interventional clinical study that was carried out on 10 adult patients who had missed posterior maxillary teeth and wanted to restore it, with less than 5 mm residual bone height and greater than 7 mm bone width which treated with transalveolar sinus lifting using corticocancellous bone block containing the implant from the chin bone. All patients are followed-up clinically and radiographically by cone beam computed tomography. Results Our technique was performed successfully in all cases without any signs of infection or sinusitis and all implants inserted were clinically stable after 6 months with radiographic significant increase in the bone height and density around the implants. Conclusion Transalveolar sinus lifting using press-fitted corticocancellous bone block containing implant from chin bone was found to be highly effective technique for posterior maxillary rehabilitation in severe atrophic posterior maxilla.

Treatment of total edentulousness by fixed implant-supported prostheses

Total edentulousness presents considerable obstacles to patients in terms of aesthetics, function, and general well-being [1]. Fixed implant-supported prostheses have emerged as a possible treatment option, providing more stability, comfort, and chewing efficiency than typical removable dentures [2]. To obtain predictable and effective outcomes, it is critical to use good case selection, detailed treatment planning, and interdisciplinary teamwork [3]. Considerations for bone quantity and quality, occlusal systems, and maintenance methods are also highlighted in order to maximize long-term prosthetic success and patient happiness [4]. This case report presents the interdisciplinary management of implant-prosthetic treatment and demonstrates the effectiveness of dental implants in the oral rehabilitation of completely edentulous patients, with a focus on the all-on-six treatment approach.

Developing and Investigating a Nanovibration Intervention for the Prevention/Reversal of Bone Loss Following Spinal Cord Injury.

Osteoporosis disrupts the fine-tuned balance between bone formation and resorption, leading to reductions in bone quantity and quality and ultimately increasing fracture risk. Prevention and treatment of osteoporotic fractures is essential for reductions in mortality, morbidity, and the economic burden, particularly considering the aging global population. Extreme bone loss that mimics time-accelerated osteoporosis develops in the paralyzed limbs following complete spinal cord injury (SCI). In vitro nanoscale vibration (1 kHz, 30 or 90 nm amplitude) has been shown to drive differentiation of mesenchymal stem cells toward osteoblast-like phenotypes, enhancing osteogenesis and inhibiting osteoclastogenesis simultaneously. Here, we develop and characterize a wearable device designed to deliver and monitor continuous nanoamplitude vibration to the hindlimb long bones of rats with complete SCI. We investigate whether a clinically feasible dose of nanovibration (two 2 h/day, 5 days/week for 6 weeks) is effective at reversing the established SCI-induced osteoporosis. Laser interferometry and finite element analysis confirmed transmission of nanovibration into the bone, and microcomputed tomography and serum bone formation and resorption markers assessed effectiveness. The intervention did not reverse SCI-induced osteoporosis. However, serum analysis indicated an elevated concentration of the bone formation marker procollagen type 1 N-terminal propeptide (P1NP) in rats receiving 40 nm amplitude nanovibration, suggesting increased synthesis of type 1 collagen, the major organic component of bone. Therefore, enhanced doses of nanovibrational stimulus may yet prove beneficial in attenuating/reversing osteoporosis, particularly in less severe forms of osteoporosis.

CBCT in Dental Implantology: A Key Tool for Preventing Peri-Implantitis and Enhancing Patient Outcomes.

(1) Introduction: Trust is a cornerstone of the patient-physician relationships. Unforeseen complications in the health care system could jeopardize patients' trust in their physicians. (2) Aim: This article presents a quantitative figure regarding foreseeing the necessity of a three-dimensional quantitative visualization of bone structure and concurrently preparing for an ancillary procedure by a dentist to successfully perform the surgery that could minimize unforeseen complications; (3) Materials and method: This retrospective study has been derived based on an analysis of 1134 patients who had received 4800 dental implants from January 2001 to August 2020, out of which 200 cases were randomly selected for this study. Each procedure during implant treatment was categorized as OPG (Orthopantomography) or OPG with CBCT as per all the procedures which included and were coded as follows, 1: Surgery & Restoration, 2: GBR (Guided Bone Regeneration), 3: GTR (Guided Tissue Regeneration), 4: Block Bone Graft, 5: Spreading, 6: Splitting, 7: Internal Sinus, 8: External Sinus, 9: PRF (Platelet Rich Fibrin). Any of the 200 cases in which implant placement could not have been performed for reasons related to a lack of CBCT were selected for this study. The surgery was aborted halfway through without implant placement in these cases due to a lack of bone quantity and/or lack of primary stability. These cases were registered for re-evaluation and statistical analysis; (4) Results: 7% of the cases that used OPG alone led the surgeon to unexpectedly abort in the middle of the surgery without implant placement. All (100%) of the patients who had CBCT during treatment planning were able to receive implants during the surgery. None of the patients left the surgery without receiving implants if CBCT was used (0%); (5) Discussion: Radiographic image quality is defined as the amount of information within the image that allows the radiologist to make a diagnostic decision with a particular level of certainty (Martin et al., 1999) and hence the importance of CBCT. The unexpected 7% of devastating situations for patients who started surgery but did not have implant placement led to [A] aborting the surgery, [B] procedural difficulties requiring an alternative treatment plan, [C] a negative impact on the patient's behavior, and [D] wanting to change doctor due to a lack of trust; (6) Conclusion: This study indicates that in implant dentistry patients' mistrust could be avoided by 7% if CBCT is obtained. It also shows the significance of cone-beam computed tomography as an adjunct to panoramic radiography during the diagnosis and treatment planning phase. The use of panoramic radiography alone can lead to a 7% likelihood of misdiagnosis. A lack of CBCT during treatment planning negatively affects the outcome of surgical procedures.

Assessment of cone-beam CT technical image quality indicators and radiation dose for optimal STL model used in visual surgical planning.

The aim of this study was to identify cone-beam computed tomography (CBCT) protocols that offer an optimal balance between effective dose (ED) and 3D model for orthognathic virtual surgery planning, using CT as a reference, and to assess whether such protocols can be defined based on technical image quality metrics. Eleven CBCT (VISO G7, Planmeca Oy, Helsinki, Finland) scan protocols were selected out of 32 candidate protocols, based on ED and technical image quality measurements. Next, an anthropomorphic RANDO SK150 phantom was scanned using these 11 CBCT protocols and 2 CT scanners for bone quantity assessments. The resulting DICOM (Digital Imaging and Communications in Medicine) files were converted into Standard Tessellation Language (STL) models that were used for bone volume and area measurements in the predefined orbital region to assess the validity of each CBCT protocol for virtual surgical planning. The highest CBCT bone volume and area of the STL models were obtained using normal dose protocol (F2) and ultra-low dose protocol (J13), which resulted in 48% and 96% of the mean STL bone volume and 48% and 95% of the bone area measured on CT scanners, respectively. The normal dose CBCT protocol "F2" offered optimal bone area and volume balance for STL. The optimal CBCT protocol can be defined using contrast-to-noise ratio and modulation transfer function values that were similar to those of the reference CT scanners'. CBCT scanners with selected protocols can offer a viable alternative to CT scanners for acquiring STL models for virtual surgical planning at a lower effective dose.

The influence of cortical end plate upon ultrasound transit time spectroscopy estimated bone assessment

Quantitative ultrasound (QUS) is considered a reliable tool for routine assessment of bone. However, none of the QUS parameters has a direct measure of bone quantity or quality. The concept of ultrasound transit time spectroscopy (UTTS) has recently offered the possibility of effective estimates of bone volume fraction (BVF) as an indicator of bone density. This study aimed to investigate the influence of cortical end plate thickness around the cancellous bone on the measurement accuracy of UTTS solid volume fraction (UTTS-SVF). Two categories of cortical discs were designed and three-dimensional printed; category (I) is planer discs of constant different thickness and category (II) is variable-thickness step-wedge discs. In this experimental and simulated study, the discs were placed coaxially with the 3D-printed cylindrical iliac crest cancellous bone sample. A through-transmission 1 MHz ultrasound pulses were recorded, from which the deconvoluted TTS were derived. Then UTTS-SVF was determined and compared with the measured SVF via microcomputed tomography (μCT-SVF) showing a high agreement with an average of 94% ± 3.7% and 95% ± 4% for the planar cortical discs and 95.3% ± 5.5% and 96.5% ± 3.7% for variable-thickness step-wedge cortical discs for experiment and simulation respectively. The variations between the derived UTTS_SVF and the standard μCT-SVF are assumed to be due to the existence of phase interference within the cortical discs. Hence, the cortical end plate creates a negative influence on the derived UTTS-SVF.

#2223 Glycosylated hemoglobin levels and bone phenotype in patients with end-stage kidney disease

Abstract Background and Aims Diabetes mellitus is common as both cause and comorbidity of patients with chronic kidney disease (CKD). Both diabetes and CKD are states of increased fracture risk compared to healthy controls, with multiple potential contributing mechanisms. In type 2 diabetes, hyperglycemia contributes to the accumulation of advanced glycation end-products and osteocyte dysfunction, and it may play a pathogenic role in bone fragility. In this study, we wanted to examine the association between glycemic status and bone phenotype in patients with end-stage kidney disease (ESKD). Method This is a cross-sectional cohort study of 626 patients with CKD G5-5D referred for kidney transplantation between April 2006 and December 2013. Patients with type 1 diabetes were excluded. Patients were divided into quartiles based on HbA1c. Laboratory parameters of bone mineral metabolism (including biointact parathyroid hormone (PTH), fibroblast growth factor-23 (FGF23), and sclerostin), and bone turnover markers (bone alkaline phosphatase (BALP), trimeric pro-collagen type 1 N-terminal pro-peptide (intact P1NP), and tartrate-resistant acid phosphatase 5b (TRAP5b)) were measured. Bone mineral density (BMD) assessed by dual-energy X-ray absorptiometry (DEXA) (n = 537), bone histomorphometry (n = 180), and bone trabecular score (TBS) (n = 192) were available for subsets of patients. Results The median HbA1c were 4.8% in Q1, 5.1% in Q2, 5.4% in Q3, and 5.9% in Q4. Age and BMI differed across quartiles, with the highest age and BMI in Q4. Differences in bone turnover markers were found, with decreasing bone formation (BALP and intact P1NP) and decreasing bone resorption (TRAP5b) with ascending quartiles (Fig. 1). No differences across quartiles were found for FGF23, or circulating levels of sclerostin; however a weak, positive correlation between HbA1c and sclerostin was noted (rho = 0.08, p = 0.047). Overall, BMD at lumbar spine, femoral neck, and total hip increased across quartiles, the highest values in Q4 (Table 1). There were no differen in bone histomorphometry or TBS based on glycemic status. Conclusion Chronic hyperglycemia associates with suppressed bone turnover and higher BMD in patients with ESKD, even in non-diabetics. Potential mechanisms linking glucose metabolism to bone quantity and quality requires further investigation.