Tissue Resorption Research Articles

Wear and corrosion characteristics of nano-crystalline tantalum nitride coatings deposited on CoCrMo alloy for hip joint applications

Osteolysis is the resorption or removal of bone tissue, which is associated with the accumulation of polyethylene particles and misalignment of hip joint implant components. The mechanical properties, adhesion, tribological, and corrosive properties of single-layered tantalum nitride (TaN) coatings on biomedical grade cobalt alloy were evaluated to determine the potential of these coatings to prevent osteolysis in hip joint replacement applications. The TaN coatings were deposited directly on biomedical grade CoCrMo alloy disks using a hybrid system of Plasma Enhanced Chemical Vapor Deposition (PECVD) and Physical Vapor Deposition (PVD) at different deposition temperatures. By increasing the deposition temperature from 350 °C to 500 °C, the mechanical properties and adhesion improved remarkably, without a significant change in the crystal structure according to XRD and XPS results. The ball-on-disk wear testing results showed that the wear rate of the polyethylene balls decreased by 5% when sliding against the TaN-500C sample compared to sliding against the uncoated alloy and was 23% lower than the TaN-350C sample. The electrochemical corrosion results indicated that the TaN coating deposited at 500 °C is about 15% more noble than the uncoated alloy, which allows the rapid formation of a protective passive layer. These results suggest that TaN is a promising coating for CoCrMo alloy to improve the lifetime of hip joint implants.

Influence of PRGF and PRF on postextractive alveolus regeneration: a randomised controlled trial.

Healing of postextraction alveolus is a complex process that involves soft and hard tissue regeneration. Pain, swelling, difficulty in opening the mouth, delayed bone tissue healing, alveolitis, and horizontal or vertical resorption of bone tissue are the main problems that impact on consequent treatment. Blood concentrates PRGF (plasma rich in growth factors) and PRF (platelet-rich fibrin), which are rich in growth factors, create better conditions for postextraction alveolus healing, enhance quality of soft tissues and bone regeneration, and decrease pain. The study objective was to compare physiologic healing of the postextraction zone with PRF- and PRGF-induced changes. In total, 43 patients were randomly divided into three groups: control group (mandibular molar extraction and filling of postextraction alveolus with hemostatic sponge containing gentamicin), group 2 (postextraction alveolus filled with PRGF), and group 3 (postextraction alveolus filled with PRF). Bone regeneration was evaluated in CBCT scans after 1 month. Pain was evaluated using the visual analog scale (VAS). After evaluating VAS results 1 day after surgery the lowest pain score was in the PRGF group. Tooth alveolus vertical and diagonal dimensions in the control group were significantly (P = .017) smaller than in the PRGF group. The vertical dimension of the alveolar ridge did not change significantly (P = .859) in the PRGF group; however, it was significantly reduced (P = .04) in the PRF group. One month after surgery the age of the control group was inversely proportionally correlated with the height and diagonal dimension of callus. Both blood concentrates had great anti-inflammatory properties, but PRGF had better osteoblastic properties and resulted in lower postoperative pain.

Инструментальные и биохимические показатели состояния костной ткани при остеомаляции и остеопорозе

Актуальность. Снижение минеральной плотности костной ткани (МПКТ), возникающее при остеомаляции (ОМ) и остеопорозе (ОП), сопровождается уменьшением прочностных свойств костных структур и ростом риска переломов. Несмотря на одинаковый клинический исход (переломы), морфоструктурные, этиологические и патогенетические характеристики ОП и ОМ качественно различаются. Цель исследования: изучить диагностические критерии остеомаляции и остеопороза в постменопаузе. Материалы и методы. Обследовано 157 постменопаузальных (ПМ) женщин в возрасте 57,5 ± 1,2 года, у 103 из которых был диагностирован ОП (группа І) и у 24 морфометрически был установлен диагноз остеомаляции (ОМ) (группа ІІ), контрольную группу (III) составляли 30 практически здоровых женщин. Проведена рентгеновская денситометрия (остеоденситометр Hologic Discovery (USA)). Уровень 25(ОН)D в сыворотке крови определяли иммуноферментным методом на анализаторе EUROIMMUN (Германия). Маркер резорбции КТ С-терминальный телопептид коллагена 1-го типа (СТх), остеокальцин (ОК) и паратгормон (ПТГ) — иммунохемилюминесцентным методом, уровень фосфора — спектрофотометрическим методом на анализаторе Cobas 6000 (Roche Diagnostics, Швейцария). Уровень остеопротегерина (ОПГ) определяли методом иммуноферментного анализа на аппарате AxsymSystem (Abbot, Германия), статистическую обработку проводили с помощью прикладных программ Microsoft Office Excel и Statistica 10.0. Для математической обработки использовали t-критерий Стьюдента. При оценке силы связи коэффициентов корреляции использовали шкалу Чеддока. Результаты. Анализ полученных данных показал снижение МПКТ (р < 0,05) в І и ІІ группах. Однако BMD neck, Т-критерий neck, Z-критерий neck в группе женщин с ОМ были значимо снижены (р < 0,05) в сравнении с группой с ОП. Уровни 25(ОН)D, ОК, ОПГ были также снижены (р < 0,05) во ІІ группе женщин по сравнению с І группой. Были получены более высокие (р < 0,05) показатели ПТГ и СТх в группе пациенток с ОМ в сравнении с группой лиц с ОП. Корреляционный анализ полученных результатов показал связь уровня 25(ОН)D с показателями структурно-функциональных изменений КТ: 25(ОН)D и СТх (r = –0,669; р = 0,001), 25 (ОН)D и BMD neck (r = 0,736; р = 0,002). Также выявлена прямая связь между BMD neck и СТх (r = –0,463; р = 0,002). Выводы. У ПМ женщин с ОМ в сравнении с ПМ женщинами с ОП выявлены значимо большие (р < 0,05) изменения структурно-функционального состояния КТ, биохимических маркеров резорбции и ремоделирования КТ, а также более низкий (р < 0,05) уровень 25(ОН)D. Содержание 25(ОН)D обладает высокой информативностью в плане прогнозирования и диагностики снижения МПКТ и риска переломов. Биохимический маркер резорбции СТх обладает высокой информативностью в плане прогнозирования, своевременной диагностики и эффективности лечения снижения МПКТ.

Influence of Soft Tissue and Crestal Bone Resorption in Moderate Cigarette-Smokers and Nonsmokers: A 5-Year Study.

This study aimed to determine the impact of implant placement depth (bone-level [BL] and subcrestal [SC]) on soft-tissue inflammatory parameters bleeding on probing (BOP), probing depth (PD), and crestal bone resorption (CBR) in moderate cigarette-smokers and nonsmokers at 5 years postplacement. Patient details were recorded, including sex, age, smoking history, duration of implants in function, implant arch location, and daily toothbrushing and flossing habits. Peri-implant BOP, PD, and CBR were measured in all groups, and group comparisons were done; a probability score < .05 was selected as a value for statistical significance. Fifty-three patients (27 smokers, 26 nonsmokers) had BL implants, and 55 patients (28 smokers, 27 nonsmokers) had SC implants. Among all patients, PD was higher in smokers than nonsmokers (P < .05). The peri-implant sites that demonstrated BOP were higher (P < .05) in nonsmokers than smokers. Among smokers, the CBR was higher in those with BL implants than those with SC implants (P < .05). Among nonsmokers, there was a difference in BOP, PD, and CBR at the 5-year follow-up. At 5 years, SC implants demonstrated less CBR than BL implants. Peri-implant PD is higher in smokers than nonsmokers, irrespective of the implant placement depth.

Protocols for radiological diagnosis of various clinical forms of pathological tooth resorption using cone-beam computed tomography

Resorption of hard tissues in a permanent tooth is manifested by the loss of cement or dentin of the tooth. At the initial stages of development, the disease is asymptomatic, which significantly complicates early diagnosis and reduces the likelihood of a successful outcome of treatment. The pathogenesis of the disease has been studied, while the main etiological factor is not known. The researchers point only to the main factors predisposing to the development of tooth resorption. The prevalence of this condition continues to be studied using the new capabilities of cone-beam computed tomography (CBCT), which allows for the earliest and most reliable diagnosis. The three-dimensional X-ray image of the tooth structures makes it more possible to visualize dentin defects at all root levels, and when they are localized on different surfaces. It is this aspect in the diagnosis of pathological tooth resorption that is crucial, since it determines the treatment tactics in general, and the creation of access in conservative surgical treatment. This method of radiation diagnostics has become the standard for examining a dental patient in the clinics of the Department of Dentistry of the MED Clinic System. The algorithm of reading and interpreting the data of computer tomograms, developed in SPBINST, is also used. Examination of dental patients involves the use of CBCT for the preparation of a comprehensive treatment plan, during all types of endodontic treatment, and for monitoring during follow-up in dynamics.

Prosthetic rehabilitation of maxillary lateral incisors agenesis using dental mini-implants: a multicenter 10-year follow-up

ObjectivesImplants are used to replace congenitally missing lateral incisors but often the space across the alveolar crest is too narrow to permit their use. This multicenter study (Dental Clinic of the University of Foggia, Odontostomatology Clinic of the University of L’Aquila) evaluated the efficacy of mini-implants in cases of maxillary lateral incisor agenesis with severe osseous atrophy in 10-year follow-up.Materials and methodsForty-seven mini-implants have been inserted in 35 patients affected by lateral incisors agenesis (23 single and 12 bilateral ageneses). All patients underwent orthodontic opening of the space of the upper lateral incisors. After the insertion of the implants, the immediate, non-functional loading, positioning of crowns, presence of pain during percussion and mini-implant function, horizontal and vertical movement when a force of 5 N was applied, ridge loss, and plaque index have been evaluated 1 month after loading, 1 year after loading, and then every 5 years in the following 10 years. Little’s test was used to evaluate the assumption that data of loss to follow-up implants are missing completely at random (MCAR) and that a complete-case scenario could be adopted. Wilcoxon test was carried out to look statistically significant differences between the various parameters resulting in the complete-case scenario and those assumed for the worst scenario. The software R (v. 3.6.1, 2019) was employed to perform the statistical analysis.ResultsThe results obtained over 10 years range from 89% of success rate in a worst-case scenario to the 100% using a complete-case analysis with satisfactory values of marginal bone resorption and good conditions of the peri-implant tissue. Ten-year follow-up using complete-case analysis shows survival rates of 100% for implants with no signs of peri-implantitis, stability of the marginal bone levels and soft tissue around the dental implants.ConclusionsThe data collected show very good implant stability, absence of progressive peri-implantitis, and satisfactory aesthetical results in time (no signs of infraocclusion).Clinical relevanceMini-implants can be considered a valid and stable over time solution in the restorative treatment of maxillary lateral incisors agenesis.

3D-Printed Regenerative Magnesium Phosphate Implant Ensures Stability and Restoration of Hip Dysplasia.

Osteoarthritis of the hip is a painful and debilitating condition commonly occurring in humans and dogs. One of the main causes that leads to hip osteoarthritis is hip dysplasia. Although the current surgical methods to correct dysplasia work satisfactorily in many circumstances, these are associated with serious complications, tissue resorption, and degeneration. In this study, a one-step fabrication of a regenerative hip implant with a patient-specific design and load-bearing properties is reported. The regenerative hip implant is fabricated based on patient imaging files and by an extrusion assisted 3D printing process using a flexible, bone-inducing biomaterial. The novel implant can be fixed with metallic screws to host bone and can be loaded up to physiological loads without signs of critical permanent deformation or failure. Moreover, after exposing the hip implant to accelerated in vitro degradation, it is confirmed that it is still able to support physiological loads even after losing ≈40% of its initial mass. In addition, the osteopromotive properties of the novel hip implant is demonstrated as shown by an increased expression of osteonectin and osteocalcin by cultured human mesenchymal stem cells after 21 days. Overall, the proposed hip implant provides an innovative regenerative and mechanically stable solution for hip dysplasia treatment.

Консервативне лікування порушень метаболізму кісткової тканини у хворих на вітамін-D-залежний рахіт ІІ типу з генетичним ушкодженням формування колагену І типу

Мета дослідження: визначити вплив консервативної терапії на генетично зумовлені порушення метаболізму кісткової тканини у хворих на D-залежний рахіт ІІ типу з генетичним ушкодженням формування колагену І типу. Матеріали та методи. На базі консультативно-поліклінічного відділу ДУ «Інститут травматології та ортопедії НАМНУ» було обстежено та проліковано 13 пацієнтів із діагнозом вітамін-D-залежного рахіту ІІ типу з генетичним ушкодженням формування колагену І типу (ВДЗР(COL1)). Консервативне лікування пацієнтів з даним рахітоподібним захворюванням проводилось у 4 етапи. Перший етап включав повне обстеження пацієнта щодо рівня кальцію, фосфору крові та сечі, кальцидіолу та кальцитріолу крові, показників паратиреоїдного гормону та остеокальцину, а також маркера кісткоутворення P1NP і маркера остеорезорбції β-CTx. На першому етапі в обов’язковому порядку діти проходили генетичне дослідження для виявлення змін (поліморфізму) в алелях рецепторів до вітаміну D та колагену І типу. Обстеження на наступних етапах проводилось у повному обсязі, окрім генетичних досліджень. Результати. Виявлено, що генетично зумовлене порушення рецепції вітаміну D призводить до значного акумулювання активного метаболіту вітаміну D у сироватці крові, що при поєднанні даної патології з генетично детермінованим порушенням формування колагену І типу вірогідно впливало на процеси кісткоутворення/кісткоруйнування із залученням механізмів компенсації остеомаляційного процесу (система «паратгормон — вітамін D — остеокальцин»). Всебічне вивчення метаболізму вітаміну D та біохімічних показників життєдіяльності кісткової тканини у хворих на ВДЗР(COL1) дозволило впритул підійти до розуміння деяких питань патогенезу та сутності остеомаляційних, а в подальшому — остеопоротичних змін різного ступеня, об’єктивувати ці зміни у відповідних показниках біохімічного дослідження та залежно від змін розробити різні схеми медикаментозної корекції порушень кісткового обміну при даному захворюванні. Висновки. Порушення рецепції до кальцитріолу в поєднанні з генетично зумовленим порушенням формування колагену І типу відображає найбільш тяжкі порушення метаболізму кісткової тканини при вітамін-D-залежному рахіті, що, у свою чергу, викликає в організмі дитини, яка росте, прискорення кісткового обміну та прогресування остеомаляційних процесів поряд зі значним прискоренням розсмоктування кісткової тканини. Це, на нашу думку, пов’язано з формуванням недосконалого колагену, який організм дитини намагається перебудувати, хоча дане припущення потребує подальшого вивчення.

Is the determination of bone turnover markers and vitamin D useful in the diagnosis of degeneration spine disease?

Abstract: Degenerative disease of the lumbar spine is one of the most common diseases of the human musculoskeletal system and a significant public health problem. The main manifestation of degenerative spine disease is back pain, which in most cases is treated symptomatically rather than causally. The diagnosis of degenerative spine disease has been previously based on medical history and diagnostic imaging. Recently, much attention has been devoted to the biochemical indicators of bone and cartilage metabolism, which are well understood among patients with osteoporosis. Bone turnover markers indicate the metabolic activity of bone and cartilage. They occur in blood serum, urine, and synovial fluid in the form of collagen-derived proteins or enzymes, involved in the formation or resorption of bone and cartilage tissue. The study below was aimed at assessing the usefulness of determining the markers of bone turnover and cartilage damage in the blood serum of people with degenerative disease of the lumbar spine diagnosed by MRI. The biochemical diagnostics included the measurement of inflammatory parameters. The results show that the degenerative disease of the spine is local, accompanied by inflammation, and vitamin D deficiency is among the factors leading to its development.

Корекція порушень ремоделювання кісткової тканини при довготривалій кортикостероїдній терапії

Актуальність. При тяжких дерматозах зазвичай призначаються препарати кортикостероїдних гормонів досить тривалими курсами і навіть довічно, у зв’язку з чим діагностика виникнення побічних ефектів від тривалого використання системних глюкокортикостероїдів (ГКС), зокрема порушень кісткового обміну, а також їх профілактика є важливою складовою комплексної терапії тяжких дерматозів. Тому розробка методів ранньої діагностики, лікування і профілактики появи порушень ремоделювання кісткової тканини під впливом тривалої глюкокортикостероїдної терапії у хворих на тяжкі дерматози вкрай актуальна для сучасної дерматології. Мета дослідження — підвищення ефективності та безпечності лікування хворих на тяжкі дерматози шляхом запобігання або мінімізації розвитку побічних ефектів лікування глюкокортикостероїдними гормонами. Матеріали та методи. У дослідження було залучено 134 хворих на тяжкі дерматози (акантолітична пухирчатка, бульозний пемфігоїд, дерматоз Дюрінга, еритродермія тощо). Використовувалися клініко-анамнестичні, біохімічні, цитологічні, імуноферментні, інструментальні та статистичні методи дослідження. Результати. У хворих у результаті тривалої системної глюкокортикостероїдної терапії виявлялося вірогідне зниження кісткової фракції лужної фосфатази у 2,1 раза, рівня остеокальцину — у 6,6 раза і підвищення рівня С-кінцевого телопептиду у 2,2 раза. За даними ультразвукової денситометрії, остеопенію було виявлено у 35,5 %, остеопороз — у 64,5 % пацієнтів. Для корекції ремоделювання кісткової тканини призначалися препарати кальцію з вітаміном D3 та антирезорбтивний засіб. У результаті відзначалося підвищення зазначених показників, що свідчило про відновлення процесів остеосинтезу та нормалізацію процесів резорбції кісткової тканини, що підтверджувалося підвищенням мінеральної щільності кісткової тканини в 1,8 раза. Для запобігання розвитку порушень процесів ремоделювання кісткової тканини в комплексному лікуванні призначалися препарати антирезорбтивної дії, кальцію і вітаміну D3 в поєднанні із системними ГКС протягом усього курсу терапії. Висновки. Проведене дослідження дозволило підвищити ефективність та безпеку терапії хворих на тяжкі дерматози шляхом запобігання або мінімізації розвитку побічних ефектів лікування глюкокортикостероїдами.

Deferoxamine Reduces Inflammation and Osteoclastogenesis in Avulsed Teeth.

Replacement and inflammatory resorption are serious complications associated with the delayed replantation of avulsed teeth. In this study, we aimed to assess whether deferoxamine (DFO) can suppress inflammation and osteoclastogenesis in vitro and attenuate inflammation and bone resorption in a replanted rat tooth model. Cell viability and inflammation were evaluated in RAW264.7 cells. Osteoclastogenesis was confirmed by tartrate-resistant acid phosphatase staining, reactive oxygen species (ROS) measurement, and quantitative reverse transcriptase–polymerase chain reaction in teeth exposed to different concentrations of DFO. In vivo, molars of 31 six-week-old male Sprague–Dawley rats were extracted and stored in saline (n = 10) or DFO solution (n = 21) before replantation. Micro-computed tomography (micro-CT) imaging and histological analysis were performed to evaluate inflammation and root and alveolar bone resorption. DFO downregulated the genes related to inflammation and osteoclastogenesis. DFO also reduced ROS production and regulated specific pathways. Furthermore, the results of the micro-CT and histological analyses provided evidence of the decrease in inflammation and hard tissue resorption in the DFO group. Overall, these results suggest that DFO reduces inflammation and osteoclastogenesis in a tooth replantation model, and thus, it has to be further investigated as a root surface treatment option for an avulsed tooth.

Osteoclastic Activity in Orthodontic Tooth Movement- A Review

It is a well-known concept that bone remodeling occurs during orthodontic tooth movement. The orthodonticliterature is vastly full of information about the changes occurring on the periodontal ligament level.However, changes occurring in the alveolar bone are being elucidated. What we know about bone resorptionhas changed a lot in the last few decades. The osteoclast is the only cell to nibble and breakdown the bone,and also aids in formation and resorption of bone tissue. In this review, we briefly describe the phases andtheories of tooth movement and also the changes involved during orthodontic tooth movement.

Labelling experiments in red deer provide a general model for early bone growth dynamics in ruminants

Growth rates importantly determine developmental time and are, therefore, a key variable of a species' life history. A widely used method to reconstruct growth rates and to estimate age at death in extant and particularly in fossil vertebrates is the analysis of bone tissue apposition rates. Lines of arrested growth (LAGs) are of special interest here, as they indicate a halt in bone growth. However, although of great importance, the time intervals between, and particularly the reason of growth arrests remains unknown. Therefore, experiments are increasingly called for to calibrate growth rates with tissue types and life history events, and to provide reliable measurements of the time involved in the formation of LAGs. Based on in vivo bone labelling, we calibrated periods of bone tissue apposition, growth arrest, drift and resorption over the period from birth to post-weaning in a large mammal, the red deer. We found that bone growth rates tightly matched the daily weight gain curve, i.e. decreased with age, with two discrete periods of growth rate disruption that coincided with the life history events birth and weaning, that were visually recognisable in bone tissue as either partial LAGs or annuli. Our study identified for the first time in a large mammal a general pattern for juvenile bone growth rates, including periods of growth arrest. The tight correlation between daily weight gain and bone tissue apposition suggests that the red deer bone growth model is valid for ruminants in general where the daily weight gain curve is comparable.

The Obesity nd Periodontal Disease

Obesity is multifactorial disease affecting developing and developed countries worldwide. It is systemic condition associated with several diseases with increased rate of morbidity and mortality. It is major public health problem with various comorbidities affecting general as well as oral health. Periodontitis is an inflammatory condition resulting in destruction of supporting structures of teeth, connective tissue, periodontal ligament and alveolar bone resorption. There is possible correlation of obesity and periodontal disease. This article aim to review about the relationship about periodontitis and obesity and recommend some possible measures to detect cases at an early stage .

ETIOPATHOGENETIC MECHANISMS OF PERIODONTAL DISEASES AGAINST THE BACKGROUND OF VIRAL LIVER DISSEASES

The article presents a review and analysis of relevant available literature sources on etiopathogenetic mechanisms of periodontal disease and liver diseases of viral aetiology, and, in particular, hepatitis B and C viruses. Significant prevalence, pronounced polymorphism of clinical hepatic and extrahepatic manifestations, the incidence rate of liver cirrhosis and hepatocellular carcinoma allows us to consider hepatitis of viral aetiology as a medical and social challenge. Multi-vector liver dysfunctions can cause oral presentations in this group of patients, and in particular, in their periodontal tissues. Viral liver damage is associated with significant impairment of the microbiocenosis in gingival sulcus and periodontal pockets. Dysbiotic changes are characterized by an increase in the number of opportunistic pathogens and anaerobic periodontal pathogens. Exacerbation of dysbiosis along with deterioration of oral hygiene occurs as a consequence of reduced local resistance and hyposalivation due to the sialotropic properties of hepatitis C virus. Significant pathogenetic role in the development of periodontal disease is played by disorders of metabolic and synthetic functions of the liver, as well as hormonal imbalance, metabolic disorders, immune-mediated damage, induction of autoimmune mechanisms and cytokine imbalance. The formation of hepatogenic osteopenia and osteoporosis enhances the loss of bone mass of the alveolar processes in the jaws and, accordingly, the resorption of bone tissue with the further progression of more aggressive forms of generalized periodontitis.

The pathogenesis of bone metastasis in solid tumors: a review

Owing to its frequent occurrence and severe clinical picture, bone metastasis is an important problem in the clinical course of tumor diseases. Bone metastasis develops when the physiological remodeling process is disrupted by tumor cells via the same molecular mechanisms used by native bone cells. The process includes molecular crosstalk between osteocytes and osteoblasts and osteoclasts. Osteolytic bone metastasis, most often seen in breast cancer, is characterized by promoted differentiation and function of osteoclasts and reduced osteoblast function. Tumor cells take advantage of factors released by bone tissue resorption, thus establishing a vicious cycle that promotes the metastatic process. In osteoblastic metastasis, most often seen in prostate cancer, osteoblast function and differentiation are promoted, while osteoclast activity is reduced, resulting in net gain of bone tissue. Mechanisms involved in the early stages of bone metastasis and cancer cell dormancy have been understudied, and their exploration may pave the way for potential therapeutic strategies. Tumor affects the bone marrow microenvironment via exosomes, soluble factors, and membrane-bound ligands. In this way, an initial lesion is established, which after a variable duration of disseminated tumor cells dormancy progresses to an overt condition. The current review deals with basic mechanisms involved in bone metastasis formation and propagation. We illustrated a disparity between the diversity and number of factors included in the disease pathophysiology and the number of available and developing therapeutic options. We also examined new therapeutic strategies affecting molecular pathways.

MO084THE INFLUENCE OF INTRAVENOUS CORTICOSTEROIDS ON PLASMA SIRTUIN-1 AND SCLEROSTIN LEVELS IN PATIENTS WITH PRIMARY GLOMERULAR DISEASE

Abstract Background and Aims SIRT-1 is member of seven protein family that are involved in the cellular response to inflammatory, metabolic, and oxidative stress. The sirtuin family is a group of class III histone deacetylases. The best known of the family is SIRT-1. It may induce organ protection through inactivation of apoptosis and anti-inflammatory action. Sclerostin is a glycoprotein produced by the osteocytes and an inhibitor of Wnt signaling. Increased activity of sclerostin increases the resorption of bone tissue and inhibits osteogenesis. It has been hypothesized that by deacetylating histones SIRT-1 could negatively regulate sclerostin gene. That mechanism requires a confirmation in clinical setting. This exploratory study was designed to assess the influence of high doses of intravenous methylprednisolone on plasma SIRT-1 and sclerostin levels in patients with primary glomerular disease. Method The study included 40 patients (25 M, 15 F; mean age 53.1±14 years, mean eGFR 58.9±31.3 ml/min) in different stages of chronic kidney disease. 20 patients had eGFR below the median value of 46 ml/min. The main inclusion criterion was the clinical and histopathological diagnosis of primary glomerular disease and urine protein excretion &amp;gt;2.0 g/24h. The main biopsy-proven diagnoses were IgA nephropathy (13 patients) and focal segmental glomerulonephritis (FSGS) (13 patients). The patients were hospitalized to receive scheduled intravenous pulses of methylprednisolone 20-30 mg/kg/day for three consecutive days followed by oral prednisone 0.8-1.0 mg/kg/day. The blood was taken before the administration of methylprednisolone to assess SIRT-1, sclerostin, calcium, phosphate and PTH and urine for was taken for the measurement of calcium, phosphate and albumin to creatinine ratio. The same laboratory tests were repeated after 4, 7 and 30 days of steroid therapy. Results Plasma SIRT-1 during increased significantly during steroid administration (Fig.1). Plasma sclerostin did not change significantly during the study however a statistically significant correlation between the changes of SIRT-1 levels and sclerostin was found. In a multiple regression model the changes of plasma sclerotin induced by steroid therapy explained the largest part of the variance of the respective changes of plasma SIRT-1. Conclusion Plasma SIRT-1 increases during high-dose corticosteroids therapy. The negative relation between the changes of plasma SIRT-1 and plasma sclerostin may suggest a protective role of SIRT-1 against the rapid bone loss induced by corticosteroids.

Zoledronic acid modulates osteoclast apoptosis through activation of the NF-κB signaling pathway in ovariectomized rats.

Bone mass loss (osteoporosis) seen in postmenopausal women is an adverse factor for implant denture. Using an ovariectomized rat model, we studied the mechanism of estrogen-deficiency-caused bone loss and the therapeutic effect of Zoledronic acid. We observed that ovariectomized-caused resorption of bone tissue in the mandible was evident at four weeks and had not fully recovered by 12 weeks post-ovariectomized compared with the sham-operated controls. Further evaluation with a TUNEL assay showed ovariectomized enhanced apoptosis of osteoblasts but inhibited apoptosis of osteoclasts in the mandible. Zoledronic acid given subcutaneously as a single low dose was shown to counteract both of these ovariectomized effects. Immunohistochemical staining showed that ovariectomized induced the protein levels of RANKL and the 65-kD subunit of the NF-κB complex mainly in osteoclasts, as confirmed by staining for TRAP, a marker for osteoclasts, whereas zoledronic acid inhibited these inductions. Western blotting showed that the levels of RANKL, p65, as well as the phosphorylated form of p65, and IκB-α were all higher in the ovariectomized group than in the sham and ovariectomized + zoledronic acid groups at both the 4th- and 12th-week time points in the mandible. These data collectively suggest that ovariectomized causes bone mass loss by enhancing apoptosis of osteoblasts and inhibiting apoptosis of osteoclasts. In osteoclasts, these cellular effects may be achieved by activating RANKL-NF-κB signalling. Moreover, zoledronic acid elicits its therapeutic effects in the mandible by counteracting these cellular and molecular consequences of ovariectomized.

Pregnancy, orthodontics and bone resorption

Pregnant women present different changes in the skeletal system, such as the increase in calcium throughout this period, there are also small reductions in bone density. Orthodontic tooth movement is based on the principles of tissue resorption and formation at the level of the surrounding bone and periodontal ligament. It should be noted that there are multiple factors that affect the speed of this type of movement. During pregnancy and lactation, certain alterations in orthodontic dental movement may be perceived, caused by changes in bone homeostasis, alterations in tooth resorption and observed bone deposition. In this article we will cover topics such as the physiology and history of pregnancy, as well as the analysis of various articles related to orthodontic dental movement in pregnant women.

X-RAY BASED IMAGING AND 3D RECONSTRUCTION OF DENTAL PATHOLOGIES ON THE EXAMPLE OF PALAEOANTHROPOLOGICAL FINDING

Abstract. Findings from Bronze Age burials of Shengavit settlement have become a source of multiple studies referred to anthropological, and especially odontological, research based on 3d imaging and image processing techniques. The currently presented case is an example of palaeopathological analysis of bone tissue resorption caused by complications of dental pathologies. Thus by analogy with diagnostic procedures in clinical dentistry, conventional x-ray based cone-beam tomographic scanning have been applied and have shown its effectiveness as a study method. Through CBCT imaging we managed to reveal a hidden pathological process in the body of the studied semi-mandible fragment, though initially another pathological area located on the same finding was planned to be studied. Application of micro-computed tomography has improved analytical, or diagnostic, part of the current palaepathological study. It has brought to finding unusual morphological features hypothetically causing bone resorption as a complication of dental pathological conditions. However our intention to obtain 3d reconstructions as evidence supporting the most likely version required several attempts to correct image processing in line with the increase of imaging resolution.