Resorption Process Research Articles

Developmental Defects of Enamel Tissue from Etiology to Minimally Invasive Treatment Procedures

The development process of tissue and organs in the living body is managed by genetic components and is affected by systemic diseases or environmental factors such as trauma, chemicals and radiation. Depending on the development phase that these factors occur, conditions such as deviations from normal growth and development, and the disruptions of tissue quantity and quality may occur. Disruption of the normal functioning of the amelogenesis steps for various reasons causes defections of enamel matrix formation, resorption, and subsequent calcification process. Clinically, this situation appears as defects characterized by features ranging from diffuse opacities to the complete absence of tooth enamel. Developmental enamel defects, the prevalence of which varies between 10% and 80%, cause problems that negatively affect individuals' quality of life, such as aesthetic problems, hypersensitivity, rapidly progressing caries, and tooth tissue loss. The aim of this study was to investigate the developmental enamel defects, their relationship with the development stages of the enamel, the etiological factors, in the light of current information. Clinical management of these defects and rehabilitation with minimally invasive approaches were evaluated with exemplary cases. Keywords: Developmental enamel defects, amelogenesis, enamel hypoplasia, enamel hypomineralization, amelogenesis imperfecta. DOI: 10.7176/JSTR/6-09-07

Algorithm for the use of allergy tests

The article describes the current practice of the relationship between clinicians and laboratory doctors.The dependence in the formation of the list and content of laboratory services on the tasks put forward by the clinician is traced. These may be tests based solely on extractable markers, tests may include extract components, it is possible that in the future the tests will be epitope.The process of protein resorption into the internal environment of a macroorganism is described. The extremely important role of the microbiome of the mucous membranes and the skin in the translational destruction of protein structures is emphasized. The determining factor is that the path of penetration, bypassing the habitat of the microbiome, does not exist. The emphasis is placed on the fact that an allergological reaction is possible only in the case where protein destruction does not lead to complete degradation to amino acids, preserved protein structures, penetrating into the internal environment, are perceived by the immune system as an antigen (allergen) with the subsequent launch of a cascade of humoral and cellular reactions. This suggests that the basis of the pathogenesis of an allergic disease is the insufficiency of protein destruction factors, which are involved both from the macroorganism and from the microbiome.Normalization of the functioning of these factors should lead to the recovery of the allergic patient. ASIT should be considered as a palliative. The main and only resorption mechanism is passive diffusion. The determining role of the degree of dissociation of electrolyte solutions created by protein molecules is estimated. The microbiome is presented as an additional organ, chimeric for a macroorganism, whose role is to form barrier, protective functions, preventing the penetration of antigenic structures into the internal environment. It is concluded that the main task of the allergist doctor at the stage of diagnosis should be the desire to identify sensitization to protein homologs that make up one group. This approach makes it possible to assess the spread of sensitizationamong proteins of homologs of various nature of origin, thereby assessing the most widespread pathological process in a particular patient. Laboratory tests for the production of Simesta take into account the ideas presented, for this reason they are arranged in a system with a thought-out sequence of use, depending on the clinical manifestations and the results of the previous study. In the line of proposals there are tests of the original layout, not offered by other manufacturers. These are linear blots collected exclusively on a group basis, namely the Profilins Polcalcins blot, the PR-10, nsLTP blot, the Storageproteins blot, the Serum albumins, Lipocalins blot, the Tropomyosins blot. The test application algorithm is divided into three levels, flexibly using with reference to a specific clinical situation, the clinician’s doctor has the opportunity to obtain the most possible information at the lowest possible cost. Assessing the prospects for the development of allergology, an assumption is made about the development with subsequent implementation of epitope tests into practice, the results of the study on which will make it possible using mathematical tools to model the structure of the protein structure that has penetrated the internal environment. This will determine the missing factors of the destruction of the allergen in a particular patient, which will lead to pathogenetic treatment.

Severe Root Resorption after Obturating a Primary Molar Using Zinc Oxide and Eugenol at Different Follow-up Periods – A Case Report

AIM: The aim of this study is to present severe root resorption following obturation of the primary molar with zinc oxide eugenol (ZOE) at different follow-up periods.
 CASE REPORT: We present the case of a 6-year-old boy with decayed lower primary molars. Pulpectomy for pulpally involved primary molars was performed. ZOE has been used as root canal filling material and follow-up was done at 3, 6, and 9 months.
 CONCLUSION: External root resorption was detected at 3 months and the resorptive process continued till 9 months. This finding emphasizes the need for alternative filling material with less irritating properties.

Latest generation stents: is it time to revive the bioresorbable scaffold?

Bioresorbable scaffolds (BRS) have been introduced in the last decade in percutaneous coronary interventions. Despite several advantages being postulated, the negative results from the mid-term follow-up of the Absorb trials have tempered enthusiasm for these innovative devices. The Absorb scaffold was associated with higher rates of target-lesion failure and scaffold thrombosis when compared to current metallic stents, and for this reason was withdrawn from the market. This failure has to be considered multifactorial, involving technical and technological aspects. Continuous engineering refinements in BRS technology, means newer-generation devices are available in clinical practice, and several more are under preclinical and clinical assessment. Thinner and smaller struts, associated with a faster resorption and reendothelialization process, are at the basis of promising preclinical results for new BRS. In this review we summarize the Absorb scaffold experience and focus on the latest evidence concerning emerging new BRS, to explore if a "BRS revival" is conceivable.

Assessment of Cytocompatibility and Anti-Inflammatory (Inter)Actions of Genipin-Crosslinked Chitosan Powders.

Chitosan is a polysaccharide commonly used, together with its derivatives, in the preparation of hydrogel formulations, scaffolds and films for tissue engineering applications. Chitosan can be used as such, but it is commonly stabilized by means of chemical crosslinkers. Genipin is one of the crosslinkers that has been considered that is a crystalline powder extracted from the fruit of Gardenia jasminoides and processed to obtain an aglycon compound. Genipin is gaining interest in biological applications because of its natural origin and anti-inflammatory actions. In this paper, the ability of chitosan-based materials crosslinked with genipin to exert anti-inflammation properties in applications such as bone regeneration was studied. Powders obtained from chitosan–genipin scaffolds have been tested in order to mimic the natural degradation processes occurring during biomaterials implantation in vivo. The results from osteoblast-like cells showed that specific combinations of chitosan and genipin stimulate high permissiveness towards cells, with higher performance than the pure chitosan. In parallel, evidences from monocyte-like cells showed that the crosslinker, genipin, seems to promote slowing of the monocyte-macrophage transition at morphological level. This suggests a sort of modularity of pro-inflammatory versus anti-inflammatory behavior of our chitosan-based biomaterials. Being both the cell types exposed to microscale powders, as an added value our results bring information on the cell–material interactions in the degradative dynamics of chitosan scaffold structures during the physiological resorption processes.

The Disease Process, Diagnosis and Treatment of Invasive Cervical Resorption: A Review.

Invasive cervical resorption (ICR) is a localized, subepithelial, supra-osseous resorptive process of the tooth. Although there are several predisposing factors associated with ICR, its etiology and pathogenesis are poorly understood. The damage to the protective layer on the external root surface appears to allow for the attachment of clastic cells and initiate the resorptive process, which is confined by the inner protective pericanalar resorption-resistant sheet surrounding the root canal space. The use of cone-beam computed tomography (CBCT) is recommended for the diagnosis and assessment of a resorptive lesion. Based on the thorough evaluation of the size and location of the ICR lesion using CBCT, surgical or nonsurgical treatment can be chosen to address the source of the resorption. This review discusses the current status of knowledge regarding the biology of ICR lesions as well as their external or internal treatment using hydraulic calcium silicate-based materials. Future clinical outcome studies are necessary to evaluate the impact of hydraulic calcium silicate-based materials on the healing of ICR lesions.

Features of the Metabolism of Organic and Inorganic Matrix of Bone Tissue in Patients with Degenerative-Dystrophic Changes in the Hip Joint

Summary. In 77 patients (37 men and 40 women) of different age groups who underwent hip joint replacement, the content of calcium, phosphorus, creatinine, alkaline phosphatase and hydroxyproline in blood serum was determined. The results of a study of biochemical markers showed the predominance of osteoporotic processes in patients of elder age groups, as is evidenced by an increase in the level of free hydroxyproline and a decrease in protein-bound hydroxyproline in blood serum, as well as by an increase in the level of hydroxyproline in daily urine excretion compared with reference indices. A decrease in calcium excretion with age both in men and women can be associated with a decrease in calcium intake and its absorption in the gastrointestinal tract, which is typical for the elderly. Calcium has the greatest importance in metabolic disorders of bone tissue. Maintaining the normal state of bones in adults is associated with continuously ongoing process called “bone remodeling”. Violation of remodeling in the direction of increasing bone resorption and reducing bone formation is considered as the main reason for the development of osteoporosis. The processes of bone formation and resorption are displayed in the blood and urine at the level of various enzymes from bone tissue, by products of bone matrix synthesis or cell destruction products. Biochemical markers of osteoporosis manifestations are specific, expressing bone synthesis and resorption processes. The violations of bone metabolism reflect most objectively not the absolute indicators of mineral metabolism and metabolites of the main bone tissue protein (collagen), but the coefficient of their ratios.

Irisin deficiency disturbs bone metabolism.

Balancing the process of bone formation and resorption is important in the maintenance of healthy bone. Therefore, the discovery of novel factors that can regulate bone metabolism remains needed. Irisin is a newly identified hormone-like peptide. Recent studies have reported the involvement of irisin in many physiological and pathological conditions with bone mineral density changes, including osteopenia and osteoporotic fractures. In this study, we generated the first line of Osx-Cre:FNDC5/irisin KO mice, in which FNDC5/irisin was specifically deleted in the osteoblast lineage. Gene and protein expressions of irisin were remarkably decreased in bones but no significant differences in other tissues were observed in knockout mice. FNDC5/irisin deficient mice showed a lower bone density and significantly delayed bone development and mineralization from early-stage to adulthood. Ourphenotypical analysis exhibited decreased osteoblast-related gene expression and increased osteoclast-related gene expression in bone tissues, and reduced adipose tissue browning due to bone-born irisin deletion. By harvesting and culturing MSCs from the knockout mice, we found that osteoblastogenesis was inhibited and osteoclastogenesis was increased. By using irisin stimulated wildtype primary cells as a gain-of-function model, we further revealed the effects and mechanisms of irisin on promoting osteogenesis and inhibiting osteoclastogenesis in vitro. In addition, positive effects of exercise, including bone strength enhancement and body weight loss were remarkably weakened due to irisin deficiency. Interestingly, these changes can be rescued by supplemental administration of recombinant irisin during exercise. Our study indicates that irisin plays an important role in bone metabolism and the crosstalk between bone and adipose tissue. Irisin represents a potential molecule for the prevention and treatment of bone metabolic diseases.

Teeth resorption at cement - enamel junction (CEJ) - Microscopy analysis

The cement – enamel junction (CEJ) gains a growing interest in clinical dentistry, due to an increasing number of idiopathic tooth resorption leading to the inevitable loss of permanent dentition. Therefore, in this research study, we investigated healthy and under resorption teeth to verify junctions’ morphology in relation to the resorption process, its initiation, and propagation. Using light and scanning electron microscopy we examined the three types of CEJ: 1) coronal cementum, 2) abutment) and 3) the gap between cementum and enamel. With energy-dispersive X-ray spectroscopy (EDX) we analyzed the Ca and P concentration along the CEJ border. The study indicated the strict correlation between the gap junction and tooth resorption, due to the dentine exposure to the oral environment.

Nutritional deficiency and placenta calcification underlie constitutive, selective embryo loss in pregnant South American plains vizcacha, Lagostomus maximus (Rodentia, Caviomorpha)

Plains vizcacha females are able to ovulate up to 800 oocytes per estrus cycle. However, just 10–12 embryos are implanted and only two of them, those located nearest the cervix, are gestated to term. Between 26 and 70 days post-coitum, a constitutive resorption occurs from the embryos located proximal to the ovary, extending progressively toward those distally implanted. Our previous studies on the dynamics of gestation in L. maximus, led us to hypothesize some kind of placental and nutritional insufficiency as the basis for the resorption process. We analyzed histology and arterial architecture of the reproductive tract in pregnant and non-pregnant females. Uterine horns are irrigated through the uterine artery, a branch of the internal iliac artery, in an ascending way from the cervix; segmental arteries irrigating the embryo vesicles become thinner as they approach the ovary. Contrast solution administered during angiographies accumulated in the placenta of embryos closest to cervix. Thus, blood stream favors the embryos nearest the cervix, indicating a gradual nutritional deficiency of those closest to the ovary. Besides, placenta becomes calcified early, at mid-gestation, during the resorption process. Finally, the detection of specialized endothelial venules and inflammatory cells suggest the concurrent participation of immunological processes in embryo vesicles undergoing resorption.

SAT-364 Brown Tumor of the Mandible in Severe Uncontrolled Primary Hyperparathyroidism

Background: Brown tumors are a part of the complex “osteitis fibrosa cystica” which is a diffuse resorptive process of the bone resulting from uncontrolled hyperparathyroidism. Although these brown tumors were fairly common in the past1, the incidence of brown tumors is now extremely rare in the United States due to early diagnosis and treatment of hyperparathyroidism. Here we describe an unusual presentation for osteitis fibrosa cystica. Clinical Case: A 38 year old woman was admitted to the hospital with rapidly growing facial swelling in June 2019. The swelling initially appeared in January 2019 and had rapidly increased in size since April 2019. The mass was malodorous, painful and interfered with oral intake. The patient smoked 1 pack per day for 13 years. A CT scan of the head and neck with contrast showed a 3.6 x 4.5 x 3.3 cm mass destroying the right mandibular body, involving the right platysma muscle and displacing the central and lateral incisor teeth and was concerning for malignancy. The initial impression was that this was likely a squamous cell carcinoma with local and perhaps distant metastases, complicated by humoral hypercalcemia of malignancy and she was admitted for management.Upon admission, her calcium level was 14 mg/dL, albumin 4.1 g/dL, phosphorus 1.4 mg/dL PTH level was 890 pg/mL and vitamin D level was 22 ng/mL. Since the high PTH did not fit with hypercalcemia of malignancy, further evaluation was undertaken. A thyroid ultrasound showed a 4.6 x 1.8 x 1.5 cm isoechoic, heterogeneous lesion in the left lower pole, and Tc-99 sestamibi scan suggested parathyroid origin. The biopsy of the mouth lesion showed fibro histiocytic proliferation with multiple giant cells, negative for malignancy and consistent with a brown tumor. CT scan of the chest, abdomen and pelvis did not reveal any other masses or lytic lesions. . A skeletal survey showed another 2 cm lytic lesion in the proximal left humeral metaphysis which was not biopsied.On parathyroidectomy, the patient was found to have an enlarged left inferior parathyroid gland measuring 3.3 x 3.0 x 0.8 cm weighing 7.093 grams. Intraoperatively PTH level decreased from 890 pg/mL to 69 pg/mL. Her calcium levels returned to normal post-operatively and she was discharged home. Pathologic examination report revealed the mass to be a parathyroid adenoma. The patient reports a reduction in the size of her mandible mass since the surgery.Conclusion: Although uncommon, brown tumors can be seen in uncontrolled primary hyperparathyroidism. The mandible is a common site, though, as in this case, it is less common for it to be the only site affectedReference:1. Rosenberg, E. H. (1962). Hyperparathyroidism. A review of 220 proved cases with special emphasis on findings in the jaws. Oral Surg Oral Med Oral Pathol Oral Radiol Endod, 15(2), 84–94.

The Emerging Roles of Long Noncoding RNAs in Bone Homeostasis and Their Potential Application in Bone-Related Diseases.

Increasing evidence has announced the emerging roles of long noncoding RNAs (lncRNAs) in modulating bone homeostasis due to their potential regulating effects on bone-related cells' proliferation, migration, differentiation and apoptosis. Thus, lncRNAs have been considered as a promising gene tool to facilitate the bone regeneration process and then to predict and cure bone-related diseases such as osteosarcoma, osteoporosis, and osteoarthritis. In this review, we first enumerated several kinds of dysregulated lncRNAs and concisely summarized their regulating role in bone formation as well as resorption process. The related mechanisms were also discussed, respectively. Then, the positive or negative behavior of these lncRNAs in bone-related diseases was elucidated. This review provides an in-depth sight about the lncRNA's clinical values and limitations, which is conducive to explore new gene targets and further establish new therapeutic strategies for bone-related disease.

The Surgical Management of External Cervical Resorption: A Retrospective Observational Study of Treatment Outcomes and Classifications

IntroductionThe aims of this study were to assess the survival and clinical success of patients with teeth with external cervical resorption (ECR) who underwent surgical repair, to assess the reliability of using 2 different classification systems for ECR (Heithersay 2-dimensional classification and Patel 3-dimensional classification), and to identify if a 3-dimensional classification is a viable alternative. MethodsA retrospective study was performed in a teaching dental hospital in England. The inclusion criteria were limited to patients who underwent surgical management of ECR between 2015 and 2018. Both periapical radiographs and cone-beam computed tomographic scans of 13 patients were assessed by 2 independent dental practitioners using the Heithersay and Patel classifications. The same radiographic assessment of those records was then repeated 3 weeks later by 1 operator. These data were tested using the Cohen kappa analysis to determine inter- and intraobserver agreement. ResultsA total of 14 teeth affected with ECR were identified in 13 patients (6 women and 7 men) with a mean age of 41 years. The mean follow-up was 20 months. At follow-up, survival was noted in all cases; however, clinical success describing endodontic success, comprehensive restorative integrity, and arrest of the resorptive process was only met in 11 cases. Although helpful in describing the lesions, both classification systems displayed considerable limitations in predicting treatment outcome. A measure of Cohen kappa regarding interobserver reliability found the Heithersay classification to provide a moderate level of agreement (0.69), whereas the Patel classification provided a weak level of agreement (0.40). ConclusionsECR is a complex, aggressive, and uncommon form of external resorption. The long-term success of the treatment is predictable but strictly related to careful case selection and operative skill. In reference to ECR classifications, ambiguity still exists between their distinctive categories, leading to moderate and weak levels of interobserver agreement. Further improvement is required to enhance their use in future research.

Paediatric Metabolic Bone Disease: A Lifetime Ahead.

Beyond its functions in locomotion, support and protection of vital organs, bone also interacts with other organs to adjust mineral balance in response to physiological requirements. Bone remodelling is a continuous process of bone resorption and formation for the purpose of maintaining healthy bone mass and growth. Any derangement in this process can cause bone disorders with important clinical consequences. The most prominent features of bone diseases in children include early bone fractures, deformities and pain, which can persist and worsen later in life if an accurate and timely diagnosis is not achieved. Biochemical and genetic testing usually help to discriminate the aetiology of the disease, which determines the subsequent management and follow-up. This review focuses on major genetic metabolic bone diseases in children, their pathophysiological mechanisms, the potential therapeutic interventions and the possible consequences in adulthood of the disease and its treatments.

Features of the exchange of connective tissue and certain microelements in pregnant women with a risk of postterm pregnancy

Purpose of the study: to investigate the serum content of certain trace elements and synthesis markers (Total P1NP) and collagen resorption (β-CrossLaps) in pregnant women with a risk of postterm pregnancy and their role in this pathology.Materials and methods. Main group included 80 pregnant women with a risk of postterm pregnancy. Control group consisted of 34 pregnant women without a risk of postterm pregnancy demostrating physiologic cervical maturation. Enzyme immunoassay was used for measurement of synthesis markers (Total P1NP - N-terminal propeptide of type I collagen), connective tissue resorption (ß-CrossLaps), and trace elements - Na, K, Mg, P, total and ionized Ca.Results. Significant decrease in the concentration of Total P1NP was noted In pregnant women with a risk of postterm pregnancy compared with the control group (50.90 ± 4.27 ng/ml, p <0.05). The average value of connective tissue resorption marker β-CrossLaps in pregnant women of the main group was significantly higher than in the control ones (0.420 ± 0.02 ng/ml and 0.300 ± 0.02 ng/ml respectively). The total Ca was 1.98 ± 0.03 mmol/L that is 7.9% and 10.4% less than the lower limit of the physiological norm and in the control group (2.21 ± 0.04 mmol/l, p < 0.05) respectively. Mg in the main group was 0.68 ± 0.02 mmol/L, that is at the lower limit of the norm, and 20.9% less than in the control group (0.86 ± 0.03 mmol/L; < 0.05). The total serum vitamin D in pregnant women of the main group was 25.4% less than in the control group (23.62 ± 1.61 ng/ml, p <0.05).Conclusions. An imbalance of the most microelements significant for the normal functioning of connective tissue and processes of transmission of nervous excitation in combination with a deficiency of vitamin D contributes to a cascade of reactions that inhibit the timely restructuring of the cervix structure before childbirth. Pregnant women with a risk of overexposure are characterized by a predominance of type I collagen resorption processes over its synthesis processes, which is probably one of the reasons for the insufficient maturation of the cervix on the eve of childbirth.

Expression of PTHrP and RANKL in acquired middle ear cholesteatoma epithelium

Background: Regarded as the most important clinical characteristic of middle ear cholesteatoma, the exact mechanism of bone resorption in cholesteatoma still remains unknown.Objectives: To investigate protein expression of PTHrP and RANKL in acquired middle ear cholesteatoma epithelium and analyze their functional roles in the etiopathogenesis of bone resorption in middle ear cholesteatoma.Material and methods: A total of 22 patients who underwent surgical treatment for middle ear cholesteatoma were recruited in the study. Protein expression of PTHrP and RANKL in middle ear cholesteatoma and normal postauricular skin was investigated by immunohistochemical staining. Correlations between bone resorption degree and expression of PTHrP and RANKL were also analyzed.Results: Protein expression of PTHrP and RANKL in cholesteatoma epithelium significantly increased when compared with normal postauricular skin epithelium. In cholesteatoma epithelium, a significantly positive association was observed between PTHrP and RANKL expression. Meanwhile, obviously positive correlations between protein expression of PTHrP and RANKL and bone resorption degree were discovered.Conclusions and significance: The increased protein expression of PTHrP and RANKL in cholesteatoma epithelium, and their associations with the degree of bone resorption, revealing that PTHrP might promote bone resorption process in middle ear cholesteatoma through RANKL signaling pathway.

PDK1 is important lipid kinase for RANKL-induced osteoclast formation and function via the regulation of the Akt-GSK3β-NFATc1 signaling cascade.

Perturbations in the balanced process of osteoblast-mediated bone formation and osteoclast-mediated bone resorption leading to excessive osteoclast formation and/or activity is the cause of many pathological bone conditions such as osteoporosis. The osteoclast is the only cell in the body capable of resorbing and degrading the mineralized bone matrix. Osteoclast formation from monocytic precursors is governed by the actions of two key cytokines macrophage-colony-stimulating factor and receptor activator of nuclear factor-κB ligand (RANKL). Binding of RANKL binding to receptor RANK initiates a series of downstream signaling responses leading to monocytic cell differentiation and fusion, and subsequent mature osteoclast bone resorption and survival. The phosphoinositide-3-kinase (PI3K)-protein kinase B (Akt) signaling cascade is one such pathway activated in response to RANKL. The 3-phosphoinositide-dependent protein kinase 1 (PDK1), is considered the master upstream lipid kinase of the PI3K-Akt cascade. PDK1 functions to phosphorylate and partially activate Akt, triggering the activation of downstream effectors. However, the role of PDK1 in osteoclasts has yet to be clearly defined. In this study, we specifically deleted the PDK1 gene in osteoclasts using the cathepsin-K promoter driven Cre-LoxP system. We found that the specific genetic ablation of PDK1 in osteoclasts leads to an osteoclast-poor osteopetrotic phenotype in mice. In vitro cellular assays further confirmed the impairment of osteoclast formation in response to RANKL by PDK1-deficient bone marrow macrophage (BMM) precursor cells. PDK1-deficient BMMs exhibited reduced ability to reorganize actin cytoskeleton to form a podosomal actin belt as a result of diminished capacity to fuse into giant multinucleated osteoclasts. Notably, biochemical analyses showed that PDK1 deficiency attenuated the phosphorylation of Akt and downstream effector GSK3β, and reduced induction of NFATc1. GSK3β is a reported negative regulator of NFATc1. GSK3β activity is inhibited by Akt-dependent phosphorylation. Thus, our data provide clear genetic and mechanistic insights into the important role for PDK1 in osteoclasts.

СРАВНИТЕЛЬНАЯ ОЦЕНКА ЭФФЕКТИВНОСТИ ЭНДОДОНТИЧЕСКОГО ЛЕЧЕНИЯ ХРОНИЧЕСКОГО АПИКАЛЬНОГО ПЕРИОДОНТИТА

Subject. One of the possible causes of the development of chronic apical periodontitis is the presence of facultative and obligate-anaerobic microflora, due to the vital activity of which there is a process of resorption of the periapical periodontal tissues and a violation of the microcirculation of the mucous membrane in the area of the transitional tooth fold with apical periodontitis, and modern endodontic treatment does not always contribute to them stabilization.
 The goal is a comparative study of the effectiveness of the impact of various methods of endodontic treatment of chronic apical periodontitis using x-ray, densitometric, microbiological methods and laser dopplerography in the short and long term.
 Methodology. Under our supervision, there were 110 patients aged 20 to 30 years with chronic apical periodontitis who underwent an analysis of bone density, an assessment of the state of microcirculation of the mucous membrane in the area of the transitional fold of the causative tooth, and microbiological examination of the contents of the root canal depending on the application of the scheme endodontic treatment. Depending on the obtained clinical diagnostic data, patients with chronic apical periodontitis were divided into two clinical groups: in I, endodontic treatment was carried out according to the scheme developed by us, in II — using the standard method of endodontic treatment.
 Results. In the group of individuals with the proposed method of endodontic treatment during microbiological examination, there was a positive trend in the qualitative and quantitative decrease in gram-positive facultative anaerobic bacteria (Enterococcus spp. And β-hemolytic streptococci), according to the data of radio-visual imaging and dental computed tomography, a tendency toward faster stabilization of indicators optical density of periapical tissues, analysis of laser dopplerography data proved a significant normalization of the state microcirculation of the mucous membrane in the area of the transitional fold in the near and long term compared with the standard method.
 Conclusions. The results of a comparative study of the proposed method of endodontic treatment of chronic apical periodontitis convincingly showed its advantage.

Micromorphological assessment of bone tissue remodeling in various hip degeneration conditions.

The reorganization of bone tissue is closely associated with its metabolism and changes in its internal structure. Metabolism of the bone, which results from the simultaneous processes of resorption and formation of new bone tissue, may depend on the presence and type of arthritis. The objective of the study was to assess, based on the morphological features and mineral composition of bone tissue, changes in the femoral head in various types of hip joint degeneration. The study group consisted of 21 patients surgically treated for hip joint degeneration. They included 17 women, aged 30-70 years (mean age 52.5 years), and 4 men, aged 38-51 (mean age 48.5 years). The assessment of the morphological condition of the bone and the mineral composition of bone tissue took into account quantitative and qualitative relationships among the mineral components and bone matrix. The structure of spongious bone tissue was analyzed in histological studies, with special attention paid to osteogenesis and osteoclastic processes and the advancement of degeneration. Three main types of degenerative changes in bone tissue of the examined femoral head were recognized: osteoporosis with a prevalence of coarse-fiber bone tissue and decreased osteogenic activity; osteolysis with few osteogenesis centers; and intensified reorganization of bone tissue. In more than half of the examined samples, coarse-fiber bone tissue was replaced by newly formed bone tissue. We observed bone resorption and osteogenesis, which indicate normal homeostasis of the bone tissue. Uneven saturation of spongious bone with mineral components was found. The content of organic and inorganic bone components measured with Ca : P and C : Ca + P ratios had similar values in all types of changes. Only the bone with intense osteolysis contained a smaller quantity of carbon (4.96-8.13%). Our observations indicate an intense adaptive reorganization of bone tissue depending on external and internal factors, including biomechanical condition.

Carbon/Inorganic Hybrid Nanoarchitectures as Carriers for Signaling Elements in Electrochemical Immunosensors: First Biosensor for the Determination of the Inflammatory and Metastatic Processes Biomarker RANK‐ligand

AbstractThis work reports the development of the first integrated electrochemical immunosensor for the determination of the ligand receptor activator nuclear factor‐κB (RANKL), a biomarker that plays an important role in the regulation of bone resorption process and, as reported recently, in oncology by modulating the immune system response facilitating the tumor growth and metastatic process during cancer development. The developed platform involves a sandwich‐type immunoassay with covalent immobilization of biotinylated capture antibodies onto streptavidin/4‐aminobenzoic acid (p‐ABA) grafted screen‐printed carbon electrodes (bCAb‐Strep/p‐ABA‐SPCE) and the use of an hybrid nanomaterial composed of gold nanoparticles (AuNPs) and multi‐walled carbon nanotubes (MWCNTs) as nanocarrier of multiple detector antibody and HRP molecules. Amperometric detection with the H2O2/hydroquinone (HQ) system allowed the construction of a linear calibration plot for RANKL standards between 10.4 and 1,000 pg mL−1 with a LOD of 3.1 pg mL−1. The determination implied simple handling protocols and short assay times. The developed immunosensor was applied to the determination of RANKL in human serum of patients diagnosed with colorectal cancer (CRC) or rheumatoid arthritis (RA). Each determination required only 5 μL of undiluted serum and took less than 2 h counting since the preparation of blocked‐bCAb‐Strep/p‐ABA‐SPCE.