Experimental Model for the Study of Reparative Bone Regeneration in the Reconstruction of the Lower Jaw.

An experimental in vivo model has been developed on the rabbit mandible to study reparative regeneration of alveolar bone after intercortical split osteotomy and the role of the periosteum in the process of reparative osteogenesis. The peculiarity of this model is fixation of the periosteum over the reconstruction zone, which allows preserving the bone block displaced during surgery and leads to the formation of an organotypic structure of the regenerate with cortical and spongy bone.

[The use of an individualized mini plate for the distalization of teeth]. / Ispol'zovanie individualizirovannoi miniplastiny dlya distalizatsii zubov.

The case of treatment of a 32-year-old patient with complaints about the aesthetics of a smile and the absence of teeth 17 and 46 is presented. During the examination, it was established: the retraction position of the teeth in the frontal part of the upper jaw, the closure of the molars according to the II class of the second subclass of Engl (distal bite), the vestibular position of the teeth 13, 23. To change the spatial position of the lower jaw, the fixation of the bracket system on the upper jaw was performed. and also an individualized mini-plate was installed in the area of the zygomatic alveolar ridge on the right and left, for distalization of the dentition of the upper jaw with the help of orthodontic traction applied from the teeth to the mini-plates. This clinical example demonstrates the possibility of using individualized mini-plates for distalization of the upper dentition, as an alternative and more stable method of treatment in such clinical cases.

Micro X-ray Spectral Analysis and Comprehensive In Vivo Study of Modified Titanium Implants.

We developed a technique for the complex modification of the surface of dental implant made of VT1-0 titanium that included sequential mechanical treatment and irradiation with powerful ion beams. The chemical composition and physical properties of the surface of titanium implants (VT1-0 grade) sandblasted with subsequent acid etching, as well as subjected to complex treatment (sandblasting and irradiation with powerful ion beams) were evaluated using micro-X-ray spectral analysis. In in vivo experiments, osseointegrative properties of the implants subjected by these treatments were compared. Microrentgenospectral analysis of dental implants subjected to irradiation with powerful ion beams revealed higher indicators of surface cleanliness; in in vivo experiments, morphometric analysis also demonstrated high osseointegrative properties.

[The possibilities of endoscopic treatment of sialolithiasis]. / Vozmozhnosti éndoskopicheskogo metoda pri lechenii patsientov so sliunnokamennoi bolezn'iu.

The endosialoscopy method has opened the possibility of atraumatic removal the stones from large salivary glands. The advantage of endosialoscopic extraction of sialolithes over traditional methods of ductotomy and removal of the gland does not cause doubts, but the indications for its use are not yet clearly defined. This study analyzes the results of 75 surgical endoscopic interventions for salivary stones extraction.

[Comparative analysis of different types of implant-abutment interface on the basis of three-dimensional finite element analysis data]. / Sravnitel'nyi analiz biomekhaniki pri razlichnykh uzlakh sopriazheniia implantata i abatmenta na osnovanii dannykh trekhmernogo konechno-élementnogo modelirovaniia.

The purpose of the study was to perform a comparative static and dynamic finite element analysis of various taper and cylindrical implant-abutment connections in three-dimensional (3D) models including: abutment, fixing screw, implant, cortical bone, cancellous bone. 3D implant model was IRIS LIKO-M system (Russia) 4 mm diameter and 10 mm length. All the models (M1-M6) were built in the same way. While maintaining the external design of IRIS LIKO-M implant, they differed only by taper angle 1.25°, 5°, 9° and its height - 0.45 and 1.85 mm; the models (M7, M8) had a cylindrical connection with a joint height of 0.45 and 1.85 mm. The bone model was 6 mm width, included cortical layer was 3 mm and the inner cancellous bone. The results of static FEA of an occlusal load showed that implant with 1.85 mm abutment connection transfer strain from edge of a cortical bone to its inner layer thus preventing marginal bone resorption. The best results showed implant model with conical taper 5° and 1.85 mm height: the smallest von Mises stress in cortical layer at tightening of the fixing screw and at masticatory load, and the larger margin of safety of an implant, the abutment and the fixing screw. The results of dynamic FEA of implant with cylindrical connection demonstrate that the gap between an abutment and an implant may occur and lead to fixing screw loosening or fracture. At the same time, the implant design with knot of interface of conical type 5° remains tight at dynamic load.

[Incidence and risk factors of oral diseases in pregnant women]. / Rasprostranennost' i faktory riska razvitiia osnovnykh stomatologicheskikh zabolevanii u beremennykh.

The prevalence of tooth caries and periodontitis in pregnant women has been studied; susceptibility of pregnant women to a high risk of development of dental pathology. Proven factors that modify the risk of tooth caries, periodontitis of mild and moderate severity in pregnancy are age over 30 years, repeated childbirth and pregnancy, complications of the gestational period, and for periodontitis, additionally - diseases of the digestive system, musculoskeletal system , anemia and metabolic-endocrine disorders.

[Clinical features and treatment of patients with class III malocclusion combined with and increase and lengthening of the nose]. / Klinika i lechenie patsientov s zubocheliustnymi anomaliiami III klassa po klassifikatsii Énglia, sochetaiushchimisia s uvelicheniem i udlineniem nosa.

The aim of the study was to study the effect of orthognathic surgery using the developed method of correction of dentoalveolar anomalies on the shape of the nose in patients with Class III tooth-jaw anomalies, according to Engle's classification, combined with an increase and lengthening of the nose. In the period from 2014-2017 on the basis of FGBBO VO 'PIMU' of the Ministry of Health of Russia treated 45 patients with maxillofacial anomalies, among them 31 people diagnosed with upper retro microburnia, lower macrognathia, Engle III class, skeletal type. All patients were between the ages of 21 and 45, without severe co-morbidities. We evaluated the nasolabial angle (ÐCm-Sn-UL) characterizing the projection of the tip of the nose in patients with a skeletal form of mesial occlusion and an increase and extension of the tip of the nose before and after surgical treatment. According to the data of various authors, the value of the nasolabial angle in the norm varies from 97 to 110°. The mean nasolabial angle before the operation was 83.52±2.02°, which is much less than the recommended value, which indicates a pronounced elongation and 'droop' of the tip of the nose. The average value after the operation was 94, 90±1.88°, which on the average is 11° more than the initial data. These data indicate a change in the projection of the tip of the nose and an increase in the angle of Sm-Sn-UL, thereby improving the appearance of the patient.

[Mathematical rationale and results of clinical use of IRIS short implants]. / Matematicheskoe obosnovanie i rezul'taty klinicheskogo ispol'zovaniia korotkikh implantatov IRIS.

The aim of the study was to provide a mathematical justification of the possibility of using 6.5 mm IRIS implants and to evaluate the results of orthopedic treatment in patients with partial loss of teeth. For the calculations was constructed of a composite three-dimensional computer models: the abutment screw-implant-bone. A total of 3 models were prepared: M1-implant in the spongy bone tissue, this model corresponds to the implantation on the HF when replacing one molar; M2-2 implants in the spongy bone tissue located at a distance of 4 mm connected via abutments, this model corresponds to the implantation of RF when replacing two molars; M3-implant in the cortical bone tissue, this model corresponds to the implantation of LF when replacing one molar. Loading of implants was carried out by occlusive force applied to its end surface. The results of the calculations showed that the equivalent stresses and limiting stresses of compression-tension are within the permissible values, which were obtained by us earlier in respect of the irregular implants and are consistent with the results of calculations for other systems of short implants. The clinical part of the work consisted in the treatment of 27 patients with partial loss of teeth, who had 41 iris evolution implants with a diameter of 5 mm, length of 6.5 mm after 3 years, there was a slow bone resorption in the cervical region not exceeding 0.35 mm, which corresponds to generally accepted international standards. During the first three years of operation there were no cases of loss of established implants. Thus, the data of mathematical modeling by finite element method and retrospective three-year analysis of prosthetics on IRIS evolution implants with length of 6.5 mm showed that the use of short implants in the recovery of upper and lower jaw molars is an effective method with a high success rate at long - term and resorption level of 0.34 mm.

[Orthotopic bone implants for bone regeneration]. / Organotipichnye kostnye implantaty - perspektiva razvitiia sovremennykh osteoplasticheskikh materialov.

Biotechnology industry is rapidly developing. The elaboration of new biomaterials for bone reconstruction is one of the most perspective directions in tissue engineering. There are millions of surgical operations associated with use of bone graft materials every year. In this article we tried to analyze and systematize data about advanced technologies and modern trends in the preparation of bio-composite bone graft materials. Special attention is given to 3D-prototyping that allows making bone implants with individual form. Introduction of molecular biology technologies such as activating specific cytokines and growth factors at the right time makes it possible to optimize bone regeneration process. The article has also some suggestions on further improvement of the bone engineering technology.

Plasma Electrolytic Oxidation for Dental Implant Surface Treatment.

Current technologies of plasma electrolytic oxidation (PEO) for modifying the surfaces of dental implants made of the Grade IV titan alloy provide predictable long-term results in implant dentistry. The aim of the study is to evaluate the efficacy of PEO technology comparing two types of surface modification of dental implants made of VT1-0 medical titanium alloy. Materials and Methods: 50 IRIS dental implants (Scientific Production Company LICOSTOM, Russia), 10-mm long and 4 mm in diameter, were manufactured from the VT1-0 alloy. The implant surface was treated by two PEO methods: 1) in the aqueous solution of alkaline electrolyte without any additional modifiers (PEO-Ti); 2) in the aqueous solution of orthophosphoric acid-based electrolyte containing calcium carbonate (PEO-Ca). Implants made of VT1-0 alloy after milling and without additional treatment served as control samples. The implant surfaces were studied by electron microscopy and energy dispersive X-ray spectrometry. Some of the implants were installed in sheep, samples were obtained at 2, 4, and 8 weeks and studied by microcomputer tomography. Results: Regardless of the electrolyte composition, a highly developed porous surface was formed in the samples with PEO-modified surfaces. The surface of the PEO-Ti samples in a simple unmodified electrolyte was characterized by a large number of open pores with a wide range of size distribution from 200 nm to 3 µm. The pore size distribution was of a monomodal character, with a maximum near 0.23 µm. The PEO samples in the Ca-containing electrolyte had pores also in a wide range from ~80 nm to ~7 µm. The pore distribution, in contrast to PEO-Ti, was bimodal in nature, with the main maximum in the region of 1.05 µm and the concomitant maximum near 2.45 µm.The obtained surfaces of both types (PEO with Ca and Ti) possessed high purity and optimal microroughness for osseointegration. Both types of PEO treatment (PEO with Ca and Ti) have demonstrated a similar osseointegrative potential, nevertheless, the surface of the PEO-Ca showed a better contact with the implant surface (49.8%) than PEO-Ti (42.4%) obviously due to the presence of calcium in its composition. Conclusion: The PEO-formed implant surfaces demonstrate high osseointegrative properties after any variants of treatment and show the potential for application in osteoporosis.

Inferior alveolar nerve preservation during resection and reconstruction of the mandible for benign tumors as a factor improving patient's quality of life.

This prospective study aimed to evaluate neurosensory disturbance and quality of life in patients who underwent mandibular resection for benign tumors and whose inferior alveolar nerve (IAN) was either preserved or sacrificed. Mandibular resection was indicated owing to the presence of osteoradionecrosis in 25 patients and ameloblastoma in 15 patients. Resection was unilateral in 24 patients and bilateral in 16 patients. The authors assessed the inferior alveolar nerve's sensory dysfunction by measuring the electroexcitability of skin receptors using an electro-odontometer. Study participants' quality of life was estimated with the oral health impact profile (OHIP)-14 and short-form (SF)-36 questionnaire. All the patients in whom the inferior alveolar nerve was sacrificed experienced persistent numbness in the area of innervation with mental nerve on the affected side. The average pain threshold reached preoperative levels (point 1-22.7 ± 2.5, p-value = .025; point 2-25.8 ± 2.7, p-value = .023) 6 months after the operation in patients in whom the IAN was preserved (point 1-23.7 ± 2.3, p-value = .022; point 2-25.4 ± 2.8, p-value = .025). The results of the OHIP-14 and SF-36 showed that patients with preserved IANs had a significantly better quality of life than the patients in whom the IAN was sacrificed. The results of OHIP-14 twelve months after the operation in unilateral resection: control group - 16.0 ± 1.6, p-value = .029; study group - 8.0 ± 0.8, p-value = .029, and in bilateral resection: control group - 26.0 ± 3.2, p-value = .044; study group - 9.0 ± 0.7, p-value = .027. The possibility of sparing the inferior alveolar nerve should not be ignored when planning mandibular resection and reconstruction.

Application of Barophoresis in Chronic Generalized Periodontitis: a Mathematical Substantiation.

The aim of the study was to evaluate the use of barophoresis for the delivery of liquid-air drug substances to the gums using a mathematical model of the interaction of the drug mixture with periodontal tissues. Materials and Methods: The solution to the problem was preceded by generation of a geometric CAD model of the device and nozzle for barophoresis, including the nozzle and injector geometry. The Ansys SpaceClaim software package was used to generate the CAD geometry. Results: When solving the problem of finding the optimal distance from the nozzle to the gum surface, the numerical modeling showed that at a distance of 5 mm, the volume fraction of liquid in the mixture is 18-20%. The mixture actually breaks through the gum, filling 0.8 mm of the gum thickness and spreading symmetrically to the sides at a distance of up to 3 cm, forming a cavity. At a distance of 10 mm from the nozzle to the gum surface, the liquid volume fraction in the mixture close to the gum lies in a narrow range of values of 5 to 7%. The mixture touches the surface of the gums, penetrating slightly - at a distance of 0.30-0.45 mm. At a distance of 15 mm from the nozzle to the gum surface, the volume fraction of liquid in the mixture near the gum lies in the range of 2-5%. The mixture slightly touches the gum surface, getting inside at a distance of up to 0.2 mm, having practically no effect on the gum. Conclusion: The developed mathematical model confirmed the feasibility of application of barophoresis in the treatment of chronic generalized periodontitis. The optimal distance from the nozzle to the surface should be considered to be 10-15 mm. This distance is safe and allows the drug delivery to a depth of 0.45 mm.

[Development and preclinical studies of insulating membranes based on poly-3-hydroxybutyrate-co-3-hydroxyvalerate for guided bone regeneration].

Bone tissue damages are one of the dominant causes of temporary disability and developmental disability. Currently, there are some methods of guided bone regeneration employing different osteoplastic materials and insulation membranes used in surgery. In this study, we have developed a method of preparation of porous membranes from the biopolymer poly-3-hydroxybutyrate-co-3-hydroxyvalerate (PHBV), produced by a strain of Azotobacter chroococcum 7B. The biocompatibility of the porous membranes was investigated in vitro using mesenchymal stem cells (MSCs) and in vivo on laboratory animals. The cytotoxicity test showed the possibility of cell attachment on membrane and histological studies confirmed good insulating properties the material. The data obtained demonstrate the high biocompatibility and the potential application of insulating membranes based on PHBV in bone tissue engineering.

Crystallization of oral fluid components in patients with type 1 diabetes mellitus.

We systematized and described morphological criteria characterizing crystalline aggregates in mixed saliva from patients with type 1 diabetes mellitus.