Morphological features of bone tissue in "disuse atrophy" on the example of a segment of the human lower jaw: clinical experience of treatment

Current real-time science and technology techniques based on ENDORET PRGF technologies and the implementation of their results in practical medicine, provide ample opportunities for the use of cell autotransplantation for guided tissue regeneration, including in the treatment of "disuse atrophy" of the human lower jaw bone tissue with early tooth loss. The purpose of this work is to ensure the principles of biological feasibility and physiological capacity, technical rationality. The pathology in the distal segment of a lower limb, which is a vertical atrophy of bone tissue was confirmed by the methods of computed tomography, Vatech PaX-I 3D Green systems of extra-oral radiography with a scan size range of 16x9 cm, a focal spot of 0.5 mm (IEC60336) with a gray scale of 14 bits with a size of 0.2/0.3 voxel. Using ENDORET PRGF technology, according to the approved BTI protocol, autocellular grafts that have provided a positive result that meets the basic principles of the goal in restoring the mechanisms of physiological processes of normal quantitative and qualitative morphology of bone tissue, with its biological characteristics were obtained. The results of the study showed that bone tissue on a scale of shades of gray based on the classification of Hounsfield, is not characterized by a single biotype and in the area of missing 3.6 tooth belongs to the second biotype, and in the area of missing 3.7 tooth to the first biotype by its density. The indicators of densitometric determination confirmed excessive mineralization of the trabecular layer, ie vertical atrophy of bone tissue, which is in the sagittal section in the projection of the missing 36 teeth with a maximum number of 881 gray standard units (GSU), M=315 GSU (where, M is the average value of absolute number); sagittal section in the projection of the missing 37 teeth with a maximum number of 1726 GSU, M=1173 GSU. This clinical experience with the use of autocellular grafts in the treatment of "disuse atrophy" of the bone tissue of the jaws, which is essentially scientifically-research in nature, based on modern, at the same time available technologies of cell engineering and technical progress, provides a predictable result of clinical observation and deserves further research and practical testing.


Introduction
Every scientist or clinician in his professional development seeks to master and apply available universal [22,24,32,46] at the same time relevant techniques in real time for the development of science and technology [8,26] to implement their results in practical medicine. Studies using cell autotransplantation technologies [2,6] for guided tissue regeneration [7,20,33] including bone regeneration [1,14,17], which are among such directions, have become popular in 2015-2016, which is confirmed by scientific publications of both domestic and foreign scientists. Many of them are based on ENDORET PRGF technologies [41], which improves and, in our opinion, combines existing PRF techniques (platentrichfibrin -platelet-enriched fibrin).
Significant improvement of regenerative processes through the use of the patient's own blood [18,20] is a unique product concept of autogenous, universal and safe method of application, which contains growth factors and cytokines stored in the fibrin matrix and provide stimulating properties of tissue regeneration through the processes of angiogenesis, proliferation, cell migration and extracellular matrix synthesis.
The purpose of this work is to ensure the principles of biological feasibility and physiological capacity, technical rationality. The solution to this problem is selection of treatment methods and creation of conditions for restoration of barrier [9,30], remodeling [10] functions, and also restoration of masticatory efficiency by methods of implantation [4,16] with uniform distribution of occlusive load, formation of an oral lump (food grinding), providing phonetic and aesthetic requirements of the patient.

Materials and methods
The anamnesis of the disease of the patient J. was clarified by the methods of clinical researches, the main etiological factor -early tooth loss, which became the consequent mechanism of atrophy of bone tissue of the cellular part of the lower jaw. Using computed tomography techniques, including Vatech PaX-I 3D Green extra-oral radiography systems with a scan size range of 16x9 cm, minimizing the possibility of artifacts caused by patient movement. Focal spot 0.5 mm (IEC60336) with a gray scale of 14 bits with a size of 0.2/0.3 voxels and due to the short scan time, high-quality images were obtained (Fig. 1, 2), which remain and provide the best opportunities for diagnosis, while protecting the health of patients.
For guided bone regeneration, autocellular grafts were obtained using ENDORET PRGF technology, according to the approved BTI protocol. Using a vacutainer, autologous blood was collected in four sterile 9 ml tubes with 0.9 ml of 3.8 % sodium citrate per 8.1 ml of blood, followed by centrifugation (580 g) for 8 minutes at room temperature using a centrifuge for PRGF System V (VTI, Spain). Blood in vitro was divided into four layers: the upper layer -plateletpoor plasma (F1), the second -platelet-rich plasma (F2), the third layer ±0.2 ml of leukocytes, the lower layer -a clot of red blood cells. The resulting plasma in the upper two layers was divided into two fractions (F1 and F2) using a device for moving plasma PTD2. To activate coagulation and form a clot or fibrin membrane, calcium chloride (0.5 ml per 1 ml of plasma) was added to the selected fractions and the desired effect was achieved for 10 min in a PLAZMOTERM H furnace at a temperature of 36.8 °C.
The study was conducted in compliance with the basic provisions of GSR (1996)

Results
Detailed analysis of computed tomography images in sagittal sections of the segment of the lower jaw on the left, in the projection of the missing 36 (first study segment, SS1), 37 (second study segment, SS2) teeth showed that bone tissue on a scale of shades of gray based on Hounsfield classification, is not characterized by one biotype and in the area of SS1 -refers to the second biotype, and in the area of SS2 refers to the first biotype by its density. However, the indicators of densitometric determination with excessive mineralization of the trabecular layer (   in the projection of the missing 37 teeth -with a maximum number of 1726 GSU, M=1173 GSU. The reconstruction models are presented in the figures (1D, 2D) to visualize and confirm the described.
Morphometric values also show that there is a vertical atrophy of this segment and it is: SS1 -horizontal width of the upper edge of 2 mm, the distance to the mandibular canal -11.3 mm; SS2 -horizontal width of the upper edge of 2.4 mm, the distance to the mandibular canal -11.9 mm.
Given the research, taking into account the components of the updated clinical analysis, there are a number of tasks that must be considered when choosing methods of treatment and rehabilitation of the patient, namely: vertical loss of bone tissue of the cellular part and the body of the lower jaw (secondary final defect on the left of lower jaw); corticalization of the trabecular layer; unfavorable conditions for reconstructive operations, in particular bone tissue splitting; complex morphology of the body shape (sshaped) of the lower jaw; limited availability of the operating field; "complicated proposal" of choice methods; young age; trauma; unpredictable result.
Informed voluntary consent of the patient for treatment and surgery and anesthesia was obtained in accordance with the drawn up and agreed treatment plan, which provided: the stages of treatment (fig. 5); the anesthesiaregional anesthesia; the use of autocellular grafts -guided regeneration of bone tissue using endoret prgF technology, Spain); the use of bone tissue allograft; the restoration of dentition defects using subcortical implants; the providing of a therapeutic effect and control of bone tissue mineralization and the prognosis of the formation of "biological height to width" around the implants [38].
The V class (Cawood, 1988) was received after installation of implants Ø 4.0X7.5 mm in the projection of SS1 and SS2, which is presented in Fig. 6 and their positioning on the edentulous jaw.
Although high primary stabilization of implants with a force of 65H, the result of their positioning in this clinical case, with a vertical defect, requires augmentation with osteoplastic materials with the predicted result of restoration of the vertical bone defect and achievement of positive remodeling processes [40]. Inorganic foreign body "causes" the reaction of bone tissue, with the manifestation of constant processes of resorption and appositional growth [43]. Important clinical results are the creation of conditions under which stable osteointegration of alloplastic material is achieved, in this case both of the implant and the bone augmentation [47,51].
To achieve osteogenesis in the guided regeneration of bone tissue, we have provided: he presence of a matrix with osteoconductive properties (see Fig. 3-A, B, C); the processes of release of growth factors (see Fig. 3-B); the differentiation of osteogenic cells; the conditions of adequate blood supply; the stability and protection of blood clot in time (see Fig. 3-E; see Fig. 4-A, D, C).
The autologous membrane [30] of the fibrin clot (see      (Fig. 7). No less exciting clinical stage is postoperative radiological control in the early and long periods of dispensary supervision. The X-ray shadow with differentiation of shades of gray that is positive and expected result of the given treatment is accurately visualized on 3D reconstruction models of the presented image. Also, the protocol of preparation and installation of implants on observance of the basic principles of biological expediency and physiological ability and technical rationality that is shown in Fig. 8 is observed.

Discussion
After the analysis of the primary medical documentation of the patient J. (form 043 / o and radiological images), the absence of the follicular bud of 38 tooth was revealed. After all, during follicular growth and in the direction of its vertical movement, there is an appositional growth of the cellular part of the lower jaw. This factor negatively affected the development of bone tissue of the jaw segment and thus contributed to the development of "disuse atrophy" and corticalization of the trabecular layer of the bone. Its morphological adjustment, due to the early loss of 36, 37 teeth also attracts attention. Constant movements and the corresponding pressure from the tongue, as well as functional movements and strength of the masticatory muscles led to deformation of the body with the acquisition of a "sigmoid" shape of the jaw (Fig. 9).
The known significance of the mechanical effect on bone mass, described in W olf's transformation law (1892), any change in function leads to anatomical and structural changes in the tissues and organs involved in this function.
From a clinical point of view, physiological osseointegration as well as desosteointegration depend directly on the presence of teeth, which transfer functional load to bone tissue and thus stimulate constant remodeling processes, during which it is resorbed by osteoclasts, at the same time replaced by new biological material, depending on the state of the human macroorganism or "controlled" impact [27][28][29][35][36][37], with its qualitative and quantitative characteristics. Otherwise, the lack of load does not create conditions for bone remodeling processes, ie does not promote its regeneration, which distorts the biological basis and leads to corticalization or "devastation" of the trabecular layer.
Therefore, such bone tissue, as shown by clinical practice, needs to be restored by using biocompatible materials [31,35,42], which will stimulate bone regeneration without scar tissue formation, ie increased ossification and control of the effectiveness of coenzyme vitamin D3 [21].
The architecture of bone tissue in the ratio of the cortical to the trabecular layer directly depends on its blood supply. High bone density, respectively, has a high risk, in this case, to the development of atrophy in the vertical direction, both of the cell and the body segment of the lower jaw.
We know the studies of the authors who compared and   Metabolic processes in trabeculae significantly exceed metabolic activity in a number of diseases [3,19,23,39,45]. Also, the reduction of the functional load on the bone significantly affects the magnitude of biopotentials and the activity of osteoblasts, as a result of which the process of resorption again prevails over the process of osteogenesis.
Analyzing the presented scheme of "metabolic" transformations of bone tissue (Fig. 10), which is characterized by their patterns, it was found that the lack of indirect effects is asynchronously reflected in the qualitative characteristics in the ratio of organic component to mineral saturation, thereby determining its quantitative morphology as in this clinical case, led to the development of "disuse atrophy".
To date, the choice of clinician has a significant number of methods [5, 11-13, 15, 25] and materials [34], which contribute to some extent to achieve the goals or objectives. However, due to the volume of their clinical protocols, as well as technical support and economic justification, it deprives the doctor of proper use, or their fragmentary use does not give the expected result [44]. It is, taking as a matrix basis autologous "products" obtained using ENDORET PRGF technology, we have a positive result that meets the basic principles of the goal to ensure the mechanisms of physiological processes of normal quantitative and qualitative morphology of bone tissue, with its biological characteristics which highlights the novelty of the study in this work.
No less important factor is the simplicity of the method, because one macroorganism is the donor and recipient, ie the patient himself, who is always "available" and eliminates significant clinical risks, contraindications to transplantation and its rational ergonomics and thus gains priority among existing methods in practical application [46 48-50]. Therefore, based on the prospects of further research in this area, we see a detailed study of changes in bone density of the human lower jaw with the loss of teeth of people of different ages of postnatal ontogeny.
This manuscript is based on the observance of moral and ethical norms and has no signs of conflict of interest between the authors and the patient.

Conclusion
This clinical experience with the use of autocellular grafts in the treatment of "disuse atrophy" of the bone tissue of the jaws, which is essentially scientifically-research in nature, based on modern, at the same time available technologies of cell engineering and technical progress, deserves further research and practical testing