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Medicina (Kaunas, Lithuania) Jun 2022Background and Objectives: The gold standard for a successful prosthetic approach is the osseointegration of an implant. However, this integration can be a problem in...
Background and Objectives: The gold standard for a successful prosthetic approach is the osseointegration of an implant. However, this integration can be a problem in cases where the implant needs to be removed. Removing the implant with minimal damage to the surrounding tissues is important. Osteocytes cannot survive below −2 °C, but epithelial cells, fibroblasts, and other surrounding tissue cells can. Remodeling can be triggered by cryotherapy at temperatures that specifically affect osteocyte necrosis. In this study, we aimed to develop a method for reversing the osseointegration mechanism and for protecting the surrounding tissues by bone remodeling induced by CO2 cryotherapy. Materials and Methods: In this study, eight 2.8 mm diameter, one-piece mini implants were used in New Zealand rabbit tibias. Two control and six implants were tested in this study. After 2 months of osseointegration, a reverse torque force method was used to remove all osseointegrated implants at 5, 10, 20, and 30 Ncm. The osseointegration of the implants was proven by periotest measurements. Changes in bone tissue were examined in histological sections stained with toluidine blue after rabbit sacrifice. The number of lacunae with osteocyte, empty lacunae, and lacunae greater than 5 µm and the osteon number in a 10,000 µm2 area were calculated. Cryotherapy was applied to the test implants for 1 min, 2 min, and 5 min. Three implants were subjected to cryotherapy at −40 °C, and the other implants were subjected to cryotherapy at −80 °C. Results: Empty lacunae, filled osteocytes, lacunae >5 µm, and the osteon count around the implant applied at −40 °C were not significantly different from the control implants. The application of −40 °C for 1 min was found to cause minimal damage to the bone cells. The implants, which were applied for 1 min and 2 min, were successfully explanted on the 2nd day with the 5 Ncm reverse torque method. Test implants, which were applied cold for 5 min, were explanted on day 1. Tissue damage was detected in all test groups at −80 °C. Conclusions: The method of removing implants with cryotherapy was found to be successful in −40 °C freeze−thaw cycles applied three times for 1 min. To prove implant removal with cryotherapy, more implant trials should be conducted.
Topics: Animals; Dental Implants; Osseointegration; Rabbits; Tibia; Titanium; Torque
PubMed: 35888569
DOI: 10.3390/medicina58070849 -
Journal of Medicine and Life May 2022Nutrient canals (NCs) are passages containing neurovascular bundles (blood vessels, lymph vessels, and nerves). Best visualized on mandibular anterior intraoral...
Nutrient canals (NCs) are passages containing neurovascular bundles (blood vessels, lymph vessels, and nerves). Best visualized on mandibular anterior intraoral periapical radiographs (IOPAR), their presence is usually associated with underlying pathological such as diabetes mellitus (DM), hypertension (HTN), advanced periodontitis, calcium deficiency, tuberculosis, and disuse atrophy. This study aimed to (a) evaluate NC prevalence in patients with DM, HTN, and chronic periodontitis and (b) correlate the detection of NCs as an important preliminary screening tool for inherent systemic diseases like DM, HTN, and chronic periodontitis and as an investigative clue in age and gender determination. This cross-sectional study was conducted on 200 subjects. Patients with complaints of pain in the mandibular anterior teeth, deep dentinal caries, abrasion, and attrition were subjected to IOPAR of the mandibular anterior teeth region to assess NCs. An increased frequency of NCs in DM (84%), HTN (66%), and periodontitis (52%) with a significant p-value was observed. Most NCs were seen beyond the root apex (72.4%). A notable association between the duration of disease and the presence of NCs in the diabetic and hypertensive cohorts (p-value 0.047 & 0.012, respectively) was observed. However, we could not establish any association between the prevalence of nutrient canals with age and gender. Our study suggested that a higher frequency of NCs on mandibular anterior IOPAR may be employed as an ancillary screening and investigative support in underlying systemic disorders.
Topics: Chronic Periodontitis; Cross-Sectional Studies; Haversian System; Humans; Hypertension; Mandible; Periapical Periodontitis; Prevalence
PubMed: 35815094
DOI: 10.25122/jml-2022-0009 -
Journal of Maxillofacial and Oral... Jun 2022Osteomyelitis is inflammation of medullary cavities, haversian system and adjacent cortex of bone. It is devastating to patients when invasive.
BACKGROUND
Osteomyelitis is inflammation of medullary cavities, haversian system and adjacent cortex of bone. It is devastating to patients when invasive.
AIM
The purpose of this study is to retrospectively review patients diagnosed with diabetic maxillary osteomyelitis and evaluate factors relating infection & diabetes.
METHODOLOGY
Case records of patients diagnosed with diabetic maxillary osteomyelitis were studied. Patient's demographic data, predisposing factors, etiology, clinical features, culture sensitivity reports, microbiology, treatment and complications were studied. Diabetic status was confirmed by glycosylated hemoglobin (HbA1c) test. Duration of diabetes and anti-diabetic medication adherence was also studied.
RESULTS
There were 28 patients diagnosed with diabetic maxillary osteomyelitis, (23-male; 5-female). Majority of the patients (60.7%) belonged to fourth & fifth decades. Twenty (71.4%) patients had poorly controlled diabetes (HbA1c > 8%). All patients reported with random blood sugar > 200 mg/dl. Thirteen patients (46.4%) were diagnosed for diabetes on admission and 11 patients (39.3%) had poor anti-diabetic medication adherence. Predominant etiology was odontogenic infection (50%). Cases of bacterial osteomyelitis (50%) were more frequent than those of fungal osteomyelitis (32.1%). Recurrence was observed in three cases.
CONCLUSION
Non-cognizance about diabetes mellitus can prove devastating for maxillofacial region and may prove fatal for the patient.
PubMed: 35712438
DOI: 10.1007/s12663-020-01371-6 -
BioMed Research International 2022This study was conducted to better understand the specific behavior of the intraosseous fluid flow. We calculated the number and distribution of bone canaliculi around...
This study was conducted to better understand the specific behavior of the intraosseous fluid flow. We calculated the number and distribution of bone canaliculi around the osteocytes based on the varying shapes of osteocytes. We then used these calculated parameters and other bone microstructure data to estimate the anisotropy permeability of the lacunar-canalicular network. Poroelastic finite element models of the osteon were established, and the influence of the osteocyte shape on the fluid flow properties of osteons under an axial displacement load was analyzed. Two types of boundary conditions (BC) that might occur in physiological environments were considered on the cement line of the osteon. BC1 allows free fluid passage from the outer elastic restraint boundary, and BC2 is impermeable and allows no free fluid passage from outer displacement constrained boundary. They both have the same inner boundary conditions that allow fluid to pass through. Changes in the osteocyte shape altered the maximum value of pressure gradient (PG), pore pressure (PP), fluid velocity (FV), and fluid shear stress (FSS) relative to the reference model (spherical osteocytes). The maximum PG, PP, FV, and FSS in BC2 were nearly 100% larger than those in BC1, respectively. It is found that the BC1 was closer to the real physiological environment. The fluid flow along different directions in the elongated osteocyte model was more evident than that in other models, which may have been due to the large difference in permeability along different directions. Changes in osteocyte shape significantly affect the degrees of anisotropy of fluid flow and porous media of the osteon. The model presented in this study can accurately quantify fluid flow in the lacunar-canalicular network.
Topics: Bone and Bones; Haversian System; Osteocytes; Porosity; Stress, Mechanical
PubMed: 35677099
DOI: 10.1155/2022/3935803 -
Methods and Protocols May 2022Raman spectroscopy has recently been used for quantitative analyses of cortical bone tissue and related materials, such as dentin and enamel. While those analyses have...
Raman spectroscopy has recently been used for quantitative analyses of cortical bone tissue and related materials, such as dentin and enamel. While those analyses have proven useful as potential diagnostic tools, the Raman spectrum of bone encrypts a wealth of additional molecular scale details about structure and crystal arrangement, which are yet to be unfolded. Such details directly link to both bone physiology and pathology. In this work, a triple monochromator spectrometer with high spectral resolution, employed in polarized light configurations, was used to extract quantitative details about the preferential crystallographic orientation of apatite and collagen components in a human proximal femoral cortical bone sample. This body of information was then used to model the bone structure at the nanometric scale through a methodology that could be key in assessments of bone structure in health and disease.
PubMed: 35645349
DOI: 10.3390/mps5030041 -
Frontiers in Bioengineering and... 2022Femoral neck fracture (FNF) is the most serious bone disease in the elderly population. The multiscale mechanical response is a key to predicting the strength of the...
Femoral neck fracture (FNF) is the most serious bone disease in the elderly population. The multiscale mechanical response is a key to predicting the strength of the femoral neck, assessing the risk of FNF, and exploring the role of mechanosensation and mechanotransmission in bone remodeling, especially in the context of aging bone. Multiscale finite element (FE) models of the proximal femur for both young and elderly people were developed. The models included organ scale (proximal femur), tissue scale (cortical bone), tissue element scale (osteon), and cell scale [osteocyte lacuna-canalicular network (LCN) and extracellular matrix (ECM), OLCEM]. The mechanical responses of cortical bone and osteocytes in the mid-femoral neck and the differences in mechanical responses between these two scales were investigated. The mechanical responses of cortical bone and osteocyte showed significant differences between the elderly and the young. The minimum principal strains and mean SEDs of cortical bone in the elderly were 2.067-4.708 times and 3.093-14.385 times of the values in the young, respectively; the minimum principal strains and mean SEDs of osteocyte in the elderly were 1.497-3.246 times and 3.044-12 times of the values in the young, respectively; the amplification factors of minimum principal strain in the inferior (Inf), anterior (Ant), and posterior (Post) quadrants in the young were 1.241-1.804 times of the values in the elderly, but the amplification factor of minimum principal strain in the superior (Sup) quadrant was 87.4% of the value in the elderly; the amplification factors of mean SED in the young were 1.124-9.637 times of the values in the elderly. The mass and bone mineral density (BMD) of cortical bone in the femoral neck is closely related to the mechanical response of osteocytes, which provides a new idea for improving cortical bone quality. Perhaps cortical bone quality could be improved by stimulating osteocytes. Quadrantal differences of bone quality in the mid-femoral neck should be considered to improve fracture risk prediction in the future.
PubMed: 35600894
DOI: 10.3389/fbioe.2022.893337 -
Bone Reports Jun 2022Antlers are paired deciduous bony cranial appendages of deer that undergo a regular cycle of growth, death and casting, and constitute the most rapidly growing bones in...
Antlers are paired deciduous bony cranial appendages of deer that undergo a regular cycle of growth, death and casting, and constitute the most rapidly growing bones in mammals. Antler growth occurs in an appositional mode and involves a modified form of endochondral ossification. In endochondral bones, calcified cartilage is typically a transient tissue that is eventually completely replaced by bone tissue. We studied the distribution and characteristics of calcified cartilage in hard antlers from three deer species (, , ), i.e., in antlers from which the skin (velvet) had been shed. Remnants of calcified cartilage were regularly present as part of the trabecular framework in the late formed, distal antler portions in all three species, whereas this tissue was largely or completely missing in the more proximal antler portions. The presence of calcified cartilage remnants in the distal antler portions is attributed to the limited antler lifespan of only a few months, which is also the reason for the virtual lack of bone remodeling in antlers. The calcified cartilage matrix was more highly mineralized than the antler bone matrix. Mineralized deposits were observed in some chondrocyte lacunae and occasionally also in osteocyte lacunae, a phenomenon that has not previously been reported in antlers. Using synchrotron radiation-induced X-ray fluorescence (SR-XRF) mapping, we further demonstrated increased zinc concentrations in cement lines, along the inner borders of incompletely formed primary osteons, along the walls of partly or completely mineral-occluded chondrocyte and osteocyte lacunae, and in intralacunar mineralized deposits. The present study demonstrates that antlers are a promising model for studying the mineralization of cartilage and bone matrices and the formation of mineralized deposits in chondrocyte and osteocyte lacunae.
PubMed: 35519288
DOI: 10.1016/j.bonr.2022.101571 -
Journal of Fish Biology Jul 2022The authors studied the morphology of the upper and lower jaws, vertebrae and dorsal-fin rays of the teleost fish Xiphias gladius to analyse the skeletal architecture...
The authors studied the morphology of the upper and lower jaws, vertebrae and dorsal-fin rays of the teleost fish Xiphias gladius to analyse the skeletal architecture and ossification pattern. The analogies and differences among these segments were investigated to identify a common morphogenetic denominator of the bone tissue osteogenesis and modeling. The large fat glands in the proximal upper jaw and their relationship to the underlying cartilage (absent in the lower jaw) suggested that there is a mechanism that explains rostral overgrowth in the Xiphiidae and Istiophoriidae families. Thus far, the compact structure of the distal rostrum has been interpreted as being the result of remodeling. Nonetheless, no evidence of cutting cones, scalloped outer border of osteons and sequence of bright-dark bands in polarized light was observed in this study, suggesting a primary osteon texture formed by compacting of collagen matrix and mineral deposition in the fat stroma lacunae of the bone, but without being oriented in layers of the collagen fibrils. A similar histology also characterizes the circular structures present in the other examined segments of the skeleton. The early phases of fibrillogenesis carried out by fibroblast-like cells occurred farther from the already-calcified bone surface inside the fat stroma lacunae. The fibrillar matrix was compacted and underwent mineral deposition near the previously calcified bone surface. This pattern of collagen matrix synthesis and calcification was different from that of mammalian osteoblasts, especially concerning the ability to build a lacuno-canalicular system among cells. Necrosis or apoptosis of the latter and refilling of the empty lacunae by mineral deposits might explain the anosteocytic bone formation.
Topics: Animals; Bone and Bones; Collagen; Fishes; Mammals; Minerals; Osteoblasts; Osteogenesis; Perciformes
PubMed: 35481825
DOI: 10.1111/jfb.15069 -
Bioactive Materials Jan 2023Calcium phosphates (CaP) represent an important class of osteoconductive and osteoinductive biomaterials. As proof-of-concept, we show how a multi-component CaP...
Calcium phosphates (CaP) represent an important class of osteoconductive and osteoinductive biomaterials. As proof-of-concept, we show how a multi-component CaP formulation (monetite, beta-tricalcium phosphate, and calcium pyrophosphate) guides osteogenesis beyond the physiological envelope. In a sheep model, hollow dome-shaped constructs were placed directly over the occipital bone. At 12 months, large amounts of bone (∼75%) occupy the hollow space with strong evidence of ongoing remodelling. Features of both compact bone (osteonal/osteon-like arrangements) and spongy bone (trabeculae separated by marrow cavities) reveal insights into function/need-driven microstructural adaptation. Pores within the CaP also contain both woven bone and vascularised lamellar bone. Osteoclasts actively contribute to CaP degradation/removal. Of the constituent phases, only calcium pyrophosphate persists within osseous (cutting cones) and non-osseous (macrophages) sites. From a translational perspective, this multi-component CaP opens up exciting new avenues for osteotomy-free and minimally-invasive repair of large bone defects and augmentation of the dental alveolar ridge.
PubMed: 35441115
DOI: 10.1016/j.bioactmat.2022.03.012 -
Bone Jul 2022Despite their ability to reduce fracture-risk and increase Bone Mineral Density (BMD) in osteoporotic women, bisphosphonates are reported to reduce formation of new...
Despite their ability to reduce fracture-risk and increase Bone Mineral Density (BMD) in osteoporotic women, bisphosphonates are reported to reduce formation of new bone. Reduced bone formation has been suggested to lead to accumulation of microfractures and contribute to rare side effects in cortical bone such as atypical femur fractures. However, most studies are limited to trabecular bone. In this study, the cortical bone remodeling in human iliac bone specimens of 65 non-treated and 24 alendronate-treated osteoporotic women was investigated using a new histomorphometric classification of intracortical pores. The study showed that only 12.4 ± 11% of the cortical pore area reflected quiescent pores/osteons in alendronate-treated patients versus 8.5 ± 5% in placebo, highlighting that new cortical remodeling events remain to be activated. The percent and size of eroded pores (events in resorption-reversal phase) remained unchanged, but their contribution to total pore area was 1.4-fold higher in alendronate versus placebo treated patients (66 ± 22% vs 48 ± 22%, p < 0.001). On the other hand, the mixed eroded-formative pores (events with mixed resorption-reversal-formation phases) was 2-fold lower in alendronate versus placebo treated patients (19 ± 14% vs 39 ± 23% of total pore area, p < 0.001), and formative pores (event in formation phase) was 2.2-fold lower in alendronate versus placebo treated patients (2.1 ± 2.4% vs 4.6 ± 3.6%, p < 0.01), and their contribution to total pore area was 2.4-fold lower (1.3 ± 2.1% vs 3.1 ± 4.4%, p < 0.05). Importantly, these differences between alendronate and placebo treated patients were significant in patients after 3 years of treatment, not after 2 years of treatment. Collectively, the results support that cortical remodeling events activated during alendronate treatment has a prolonged reversal-resorption phase with a delayed transition to formation, becoming increasingly evident after 3-years of treatment. A potential contributor to atypical femur fractures associated with long-term bisphosphonate treatment.
Topics: Alendronate; Bone Density; Bone Remodeling; Bone and Bones; Cortical Bone; Diphosphonates; Female; Humans
PubMed: 35413490
DOI: 10.1016/j.bone.2022.116419