The effect of zinc complex of N-isopropenylimidazole on the morphological characteristics of gum tissues in experimental endodontic-periodontal lesions in rats Authors

Introduction: Combined inflammatory and destructive processes affecting the dental pulp and tissues of the periodontal complex are among the most problem diseases of the dental system. Current therapy with use of available pharmacological agents does not always allow achieving the expected positive result. In addition, often the lack of information about morphological processes in the tissues of the dental system, in particular the gums, with endodontic-periodontal lesion (EPL) limits the ability of dentists to carry out targeted pharmacotherapy with both traditional and, in particular, new medications. The aim of the study was to evaluate the morphological characteristics of gum tissues in a therapeutic context of N-isopropenylimidazole zinc complex derivative in experimental endodontic-periodontal lesion in rats. Materials and Methods: A simulation of EPL in rats was performed in two ways: simultaneous induction of acute periodontitis and parodontitis by pulp extraction and natural infection of the pulp cavity, as well as by ligation of the necks of lower incisors. The research protocols included 5 groups of animals: 1st – intact group (control-1); 2nd – animals with simulated EPL (control-2); 3rd – animals with simulated EPL and treated with Metrogyl Denta® gel (M-D); 4th – animals with simulated EPL and treated with N–isopropenylimidazole zinc complex derivative gel under the laboratory code Pilim-1; and 5th – animals with simulated EPL and treated with the combination of M-D + Pilim-1. The gum of the lower incisors was taken for morphological studies. Slides were stained with hematoxylin and eosin. Computer morphometry was performed using the ImageJ software. Results and Discussion: The substances M-D, Pilim-1 and, especially, the combination of M-D+Pilim-1 (against the background of chlorhexidine bigluconate used as oral rinse) for 14 days in rats with simulated EPL cause a significant improvement of the morphological structure of the gum with minimal residual dystrophy and sclerosis. The combination M-D + Pilim-1 led to a 1.3-time increase in epithelial thickness, and a 1.5-time decrease in acanthosis depth in comparison with M-D, while the number of capillaries and their diameter had no significant differences. Compared with Pilim-1, the epithelial thickness increased 1.5 times, and the acanthosis depth and the number of capillaries decreased 1.6 and 1.4 times, respectively, whereas the diameter of the capillaries did not change significantly. The pronounced protective effect of the combination M-D + Pilim-1 on the morphological structure of the gingival mucosa of rats with simulated EPL may be associated with antimicrobial, anti-inflammatory, regenerating, angioprotective and antioxidant properties of both M-D and Pilim-1 separately, and, possibly to a greater extent, of the combination M-D + Pilim-1. Conclusion: The substances M-D, Pilim-1 and, especially, the combination M-D + Pilim-1 (against the background of chlorhexidine bigluconate used as oral rinse) for 14 days in rats with simulated EPL have a protective effect on the epithelial structure and the connective tissue of the proper mucous plate, manifested in active normalization of pathological changes and significant restoration of their organotypic structure

Bioactivity and osteointegration of hydroxyapatite-coated stainless steel and titanium wires used for intramedullary osteosynthesis

Abstract A lot of research was conducted on the use of various biomaterials in orthopedic surgery. Our study investigated the effects of nanostructured calcium–phosphate coating on metallic implants introduced into the bone marrow canal. Stainless steel or titanium 2-mm wires (groups 1 and 2, respectively), and hydroxyapatite-coated stainless steel or titanium wires of the same diameter (groups 3 and 4, respectively) were introduced into the tibial bone marrow canal of 20 dogs (each group = 5 dogs). Hydroxyapatite coating was deposited on the wires with the method of microarc oxidation. Light microscopy to study histological diaphyseal transverse sections, scanning electron microscopy to study the bone marrow area around the implant and an X-ray electron probe analyzer to study the content of calcium and phosphorus were used to investigate bioactivity and osteointegration after a four weeks period. Osteointegration was also assessed by measuring wires’ pull-off strength with a sensor dynamometer. Bone formation was observed round the wires in the bone marrow canal in all the groups. Its intensity depended upon the features of wire surfaces and implant materials. Maximum percentage volume of trabecular bone was present in the bone marrow canals of group 4 dogs that corresponded to a mean of 27.1 ± 0.14%, while it was only 6.7% in group 1. The coating in groups 3 and 4 provided better bioactivity and osteointegration. Hydroxyapatite-coated titanium wires showed the highest degree of bone formation around them and greater pull-off strength. Nanostructured hydroxyapatite coating of metallic wires induces an expressed bone formation and provides osteointegration. Hydroxyapatite-coated wires could be used along with external fixation for bone repair enhancement in diaphyseal fractures, management of osteogenesis imperfecta and correction of bone deformities in phosphate diabetes

Limb lengthening and deformity correction in patients with severe fibular hemimelia: experience of the children's university hospital in Belgrade

Background Fibular hemimelia (FH) is a congenital disease manifested by valgus deformity and instability of the knee joint, shortening and deformity of the tibia, hypoplasia and deformities of the foot and ankle. The aim of this paper was to determine the efficacy of the strategy of separate reconstruction of the foot along with correction of tibia deformity, and then tibial lengthening in patients with FH of types 3 and 4 according to Paley. Methods This retrospective study is based on an analysis of the treatment of 12 children with severe FH. The patients, aged no older than 24 months, were treated for foot reconstruction along with correction of tibial deformity followed by a separate stage of tibial lengthening. Tibial lengthening was performed in the age 4.6 ± 1.2 years. The long-term result of treatment was evaluated at least 1 year after the end of tibial lengthening. Evaluation criteria after tibia lengthening were external osteosynthesis index, amount of lengthening, assessment of outcomes according to Lascombes. Walking ability was assessed using Gillette questionnaire. Results The approach we used gave excellent and good results in 83 % of cases after the first reconstructive stage. Complications and recurrences of deformities encountered during the first stage were eliminated during subsequent planned limb lengthening. The average magnitude of lengthening was 6.4 ± 2.4 cm (37.2 ± 12.4 % of the initial segment length). The index of external osteosynthesis was 22.9 ± 12.2 days/cm. Monofocal distraction osteosynthesis was used in 9 cases and bifocal osteosynthesis in three cases. The results of lengthening were classified by Lascombes as IA in 7 cases, IB in four cases, 2B in one case. Discussion In severe FH, the question of reconstruction or early amputation remains open. There are two opinions on the staging of reconstructive orthopedic surgery and tibial lengthening in young children with severe FH. Conclusion The strategy of reconstruction of the foot and ankle joint at an early age (16-24 months) in children with severe FH followed by lengthening of the lower leg (at the age of 4-6 years) proved to be effective and can be used when it is chosen by the patient's parents. In 3C type cases, the use of external fixation to correct the deformity and simultaneously lengthen the tibia at the first stage is an alternative reasonable strategy option

The effectiveness of Soderm® – forte gel and a new injectable dosage form of Rexod® in the complex treatment of experimental periodontitis in rats

Introduction: Insufficient effectiveness of traditional drug therapy in a treatment of patients with chronic generalized periodontitis, as well as high social significance of this problem, determines the need to search for new drugs and their compositions aimed at solving it. Aim of the study: To increase the efficacy of complex treatment of periodontitis with the administration of Soderm®-Forte gel and a new injectable form of Rexod®. Materials and methods: Experiments were performed in 50 male Wistar rats. Experimental periodontitis (EP) was simulated by ligation of the necks of lower incisors. We studied the animals with intact periodontium, untreated EP, and when traditional drug therapy (TDT), as well as the combinations of TDT with Soderm®-Forte gel and additionally with the new injectable dosage form (NIF) of Rexod® were administered. The general condition, behavior, nutrition and body weight of the animals were evaluated. The Schiller-Pisarev test and the Muhlemann-Cowell bleeding index were used, and the amount of crevicular fluid (CF) was measured. The contamination of the marginal gum with microorganisms was determined. Results and discussion: The TDT in EP has a moderate therapeutic effect, which does not lead to a sufficiently high pharmacotherapeutic effect, whereas the combinations of TDT with Soderm®-Forte and, to a greater extent, TDT with Soderm®-Forte and NIF of Rexod® have high therapeutic efficacy, which is statistically confirmed by a sharp decrease in the amount of CF, the Schiller-Pisarev test and the Muhlemann-Cowell bleeding index, as well as absolute suppression of pathogenic microorganisms. Conclusion: The combinations of TDT with Soderm®-Forte gel and NIF of Rexod® in EP in rats can significantly increase the effectiveness of the treatment. The data obtained indicate the expediency of the administration of Soderm®-Forte gel, as well as its combination with NIF of Rexod® in dental practice in the complex therapy of patients with periodontitis

Comparative Efficiency of Removable Mini-Implant Retained Dentures Using Different Attachments in Edentulous Patients

Aim. To compare the efficiency of removable mini-implant retained dentures using different types of attachment.Materials and methods. The study included 51 edentulous patients. The patients were divided into three groups according to the attachment type and abutment shape: 1) ball-and-socket attachment, ball abutment (n = 26); 2) locator attachment, equator abutment, XiVE LOCATOR system (n = 14); 3) bar attachment (n = 11). Removable dentures were made of ordinary acrylic plastic. The placement of intraosseous dental implants with their sublingual engraftment was performed according to the traditional two-stage delayed-load procedure. The efficiency of implants was evaluated using the method of M.Z. Mirgazizov and the eponymous index. The dynamics of vertical bone resorption around implants was determined using dental panoramic radiography (6 months, 1 and 2 years after the treatment). A periotest was performed 6 months after the end of the orthopaedic treatment.Results. The one-year survival rate of implants reached 96.2% in group 1, amounting to 100% in groups 2 and 3. The two-year survival rate came to 92.3% in group 1, reaching 92.9% and 100% in groups 2 and 3, respectively. Inflammatory phenomena characteristic of peri-implantitis were noted one year after the implant placement in 7.7% (n = 2) of patients in group 1 and in 7.1% of patients in group 2, with no inflammatory phenomena being observed in group 3. Two years after the implant placement, peri-implantitis was observed in 19.2% and 21.4% of patients in groups 1 and 2, respectively, coming to 9.1% in group 3. The periotest revealed that six months after the placement, implant stability was higher in group 3 for both the lower and upper jaw (in comparison with groups 1 and 2), as evidenced by the shift in periotest values towards the negative part of the scale.Conclusion. The study revealed that bar attachment, as well as locator attachment (equator abutments), of removable dentures supported by mini implants is more efficient as compared to the ball-and-socket attachment

The effect of the composition of Soderm®-Forte gel and the new injectable form of Rexod® on pathology findings in gingival tissue in experimental periodontitis in rats

Introduction: Periodontitis is the most important problem of modern dentistry. The development of new medicines and treatment regimens for patients with periodontal complex lesions is a strategic direction of modern pharmacology and dentistry. In this view, pride of place goes to morphological research, which allows not only to study the effect of drugs on pathomorphological changes in periodontal tissues, but also to estimate their therapeutic effectiveness. Aim of the study: to determine the nature of the effect of the composition of Soderm®-Forte gel and the new injectable form of Rexod® on the pathology findings in gingival tissue of rats with experimental periodontitis. Materials and methods: Experimental periodontitis (EP) was induced in rats by ligature method. The study was performed according to the following algorithm: animals with intact periodontium; animals with untreated EP; animals with EP treated with traditional drug therapy (TDT); animals with EP treated with combinations of TDT with Soderm®-Forte gel and TDT with Soderm®-Forte gel and the new injectable form (NIF) of Rexod®. For pathomorphological examination, biopsy specimen was taken from the gingival margin of the lower incisors. The ImageJ software was used for computer morphometry. Results and discussion: Examination of the gum samples revealed moderate therapeutic effects of the TDT. The combinations of TDT with Soderm®-Forte gel and, to a greater extent, TDT with Soderm®-Forte gel and the NIF of Rexod® showed high pharmacotherapeutic efficacy, manifested in rapid regeneration of the gingival tissues. Conclusion: The combination of TDT, Soderm®-Forte gel and the NIF of Rexod® shows the most beneficial effect on the pathological processes in the gum. The pharmacotherapeutic effect of the studied combination promotes the earliest regeneration of damaged gum tissues and reduces the risk of persistent pathology changes in them

Impacts of environmental change on biodiversity and vegetation dynamics in Siberia

Biological diversity is the basis for, and an indicator of biosphere integrity. Together with climate change, its loss is one of the two most important planetary boundaries. A halt in biodiversity loss is one of the UN Sustainable Development Goals. Current changes in biodiversity in the vast landmass of Siberia are at an initial stage of inventory, even though the Siberian environment is experiencing rapid climate change, weather extremes and transformation of land use and management. Biodiversity changes affect traditional land use by Indigenous People and multiple ecosystem services with implications for local and national economies. Here we review and analyse a large number of scientific publications, which are little known outside Russia, and we provide insights into Siberian biodiversity issues for the wider international research community. Case studies are presented on biodiversity changes for insect pests, fish, amphibians and reptiles, birds, mammals and steppe vegetation, and we discuss their causes and consequence

Influence of the Dielectric Matrix on the Electrical Nanocomposites Based on Oxidized Multi-Walled Carbon Nanotubes

В данной работе рассмотрено влияние окислительных обработок на свойства многослойных углеродных нанотрубок (МУНТ). Рассмотрены экспериментальные температурные зависимости электропроводности (в диапазоне температур 4,2-293 К) и полевые зависимости магнетосопротивления (в полях до 9 Тл при температуре 10 К) образцов МУНТ с модифицированными окислением поверхностными слоями, а также композитов на их основе. Установлено, что окисление поверхностных слоев МУНТ в растворах кислот ведет к изменению температурных зависимостей электропроводности. Введение МУНТ в диэлектрическую матрицу полиметилметакрилата (ПММА) приводит к температурной зависимости проводимости, близкой к типичной для прыжковой проводимости с переменной длиной прыжка для трехмерного случая.In this paper we consider the effect of oxidative treatments on the properties of multiwalled carbon nan- otubes (MWNT). The experimental temperature dependence of electrical conductivity (in the temperature range 4,2-293 K) and field dependence of magnetoresistance (in fields up to 9 Tl at 10 K) of the samples with MWCNT modified by oxidation of the surface layers, as well as the composites based on them. It was established that the oxidation of the surface layers of MWCNTs in acid solutions leads to a change in the temperature dependence of electrical conductivity. Introduction of MWCNTs in a dielectric matrix of polymethylmethacrylate (PMMA) leads to the dependence of the conductivity close to that typical for hopping conductivity with variable hopping length, three-dimensional case

Influence of the Dielectric Matrix on the Electrical Nanocomposites Based on Oxidized Multi-Walled Carbon Nanotubes

В данной работе рассмотрено влияние окислительных обработок на свойства многослойных углеродных нанотрубок (МУНТ). Рассмотрены экспериментальные температурные зависимости электропроводности (в диапазоне температур 4,2-293 К) и полевые зависимости магнетосопротивления (в полях до 9 Тл при температуре 10 К) образцов МУНТ с модифицированными окислением поверхностными слоями, а также композитов на их основе. Установлено, что окисление поверхностных слоев МУНТ в растворах кислот ведет к изменению температурных зависимостей электропроводности. Введение МУНТ в диэлектрическую матрицу полиметилметакрилата (ПММА) приводит к температурной зависимости проводимости, близкой к типичной для прыжковой проводимости с переменной длиной прыжка для трехмерного случая.In this paper we consider the effect of oxidative treatments on the properties of multiwalled carbon nan- otubes (MWNT). The experimental temperature dependence of electrical conductivity (in the temperature range 4,2-293 K) and field dependence of magnetoresistance (in fields up to 9 Tl at 10 K) of the samples with MWCNT modified by oxidation of the surface layers, as well as the composites based on them. It was established that the oxidation of the surface layers of MWCNTs in acid solutions leads to a change in the temperature dependence of electrical conductivity. Introduction of MWCNTs in a dielectric matrix of polymethylmethacrylate (PMMA) leads to the dependence of the conductivity close to that typical for hopping conductivity with variable hopping length, three-dimensional case