Radiologic evaluation of reparative osteogenesis in experimental animals during implantation of different compositions of osteoplastic materials

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Introduction: The problem of effective planning of reconstructive surgeries occupies an important place in the structure of dental pathology. The method of guided tissue regeneration is widely used in dental implantation, characterized by constant improvement of surgical treatment techniques, the use of high-tech materials, and the use of cone-beam computer diagnostics (CBCT). In 1976, J. Melcher substantiated the concept of guided regeneration of periodontal tissues by proving that the tissues surrounding the root (periodontium, bone tissue, gingival epithelium) are capable of "repopulation", which causes the healing of periodontal tissues after periodontal surgery. The technique of guided tissue regeneration has found wide application in dental implantation, various options for its use are associated with the use of various osteoplastic materials and membranes on which the timing of bone tissue regeneration and the success of the operation depend [1, 2, 5, 7]. Autogenous bone augmentation is the gold standard for the treatment of extensive bone defects before implantation [1, 6, 7]. The high incidence of tooth adentia and bone tissue deficiency in the area of ​​planned implantation leads to the search for and development of new osteoplastic materials [2]. Currently, researchers propose using autogenous bone from the zygomatic alveolar ridge [1], allogeneic mineralized and demineralized bone matrix [3, 4], a combined transplant and cortical bone of the femoral diaphysis [5] as autogenous bone. There are no studies in the literature showing the effectiveness of NRCT techniques using different volumes and combinations of autogenous bone chips and xenogeneic bone material in an experiment during NRCT, so we attempted to study this pressing issue [6, 7]. Objective: to evaluate bone regeneration in experimental animals using various combinations of autogenous bone and xenogenous material using cone beam computed tomography.
Material and methods: The experiment also involved 80 male chinchilla rabbits. For the NRCT operation, Russian biomaterials were used - xenogenous bone material (XBM) Xenograft Mineral "Cardioplant", which is calcium hydroxyapatite made from calf tissue that does not contain collagen. Bioresorbable barrier membrane Bioplate "Cardioplant" made of natural collagen. Autogenous bone chips (ABS) were collected from the lower jaw, through extraoral and intraoral access. The animals were divided into groups: 1st control group (12 rabbits) - only XBM was used. The 2nd group (36 animals) was divided into subgroups that used different ratios of autogenous shavings from the lower jaw and xenogeneic osteoplastic material. Subgroup 2A (12 animals) used a composition of a mixture of 25% CCM and 75% AKS; Subgroup 2B (12 animals) - used a mixture of 50% CCM and 50% AKS; Subgroup 2B (12 animals) - used a mixture of 75% CCM and 25% AKS. Group 3 (36 animals) used the ilium and various compositions of CCM as an extraoral donor zone. Subgroup 2A (12 animals) used a mixture of 25% CCM and 75% AKS; Subgroup 3B (12 animals) - used 50% CCM and 50% AKS; - Subgroup 3B (12 animals) - a mixture of 75% KKM and 25% AKS was used. Different volumes of osteoplastic materials were collected using a specially designed measuring spoon (Patent of the Russian Federation for Utility Model No. 221268). Radiological diagnostics of the dynamics of reparative osteogenesis in animals was performed using an Orthophos XG3D/Ceph (Sirona) computed tomograph on the 30th, 90th and 180th days after surgery.

Results. Analysis of the results of radiation diagnostics in experimental animals allowed us to establish differences in the dynamics of osteogenesis processes. On the 30th day, all animals had unclear contours of bone tissue in the surgical intervention area. On the 90th day of observation, active bone tissue restoration processes were determined in all groups. Bone tissue density in animals of group 1 (control group) was significantly lower than in animals of groups 2 and 3. A weak radiographic shadow in the area of ​​the bone defect filled with xenograft is due to the absence of bone-substituting material - autobone. On the 180th day of the experiment, osteogenesis processes continued in all animals. Analyzing CBCT, it can be noted that bone regenerates in animals where a mixture of autobone and xenograft was present (groups 2 and 3) had better results in increasing the density of newly formed bone tissue. Comparative analysis of neoosteogenesis in rabbits with ACS from the intraoral zone (Group 2) and ACS from the ilium (Group 3) also had differences. The best indicators of bone regenerate density were determined in Group 2 2B - subgroup - (a mixture of 50% CCM and 50% ACS); 2B subgroup (a mixture of 75% CCM and 25% ACS), as well as in animals of subgroup 3B of group 3 (75% CCM and 25% ACS). The obtained result allows us to conclude that an increase in the volume of ACS by 25% - 50% and CCS - over 50% leads to an increase in the effectiveness of surgical intervention. Discussion. Analyzing the obtained results, we can conclude that bone tissue reparation depends on the amount of osteoplastic materials. The analysis of the results obtained by the CBCT method allows us to conclude that the optimal ratio of the components of the BCM and the ACM from an extraoral source is a mixture of osteoplastic materials consisting of a ratio of 75% and 25%, respectively. It has been experimentally proven that a decrease in the quality of bone regenerate occurs with an increase in the volume of ACM (75%) from the extraoral zone.
Our results are consistent with the data of previous studies [8], in which one of the problems limiting the use of autogenous bone from the extraoral zone is the high content of monoblasts - osteoclast precursor cells. Therefore, 25% of ACM from an extraoral source in a composition with BCM is the optimal volume that allows for the maximum use of the osteoinductive potential of autogenous bone, while minimizing resorptive processes during bone tissue remodeling.
Conclusion. Based on the conducted studies, it can be assumed that when using only artificial xenogenic material, bone tissue reparation occurs within 180 days after the surgical intervention. The presence of autogenous plastic material in the composition of osteoplastic compositions significantly increases its osteoinductive properties, and in turn, the osteoconductive properties of the xenogenic material ensure the stability of the volume of the resulting regenerate. During plastic surgeries, it was determined that the osteoinductive effect of autogenous bone taken from the intraoral zone of the lower jaw is higher than that of the same volume of autograft taken from the extraoral zone (ilium) of experimental animals. To summarize the above, it can be stated that the best results in the course of experimental osteoplastic operations were obtained with the implantation of a composition consisting of a volume of: 75% artificial xenogenic material Xenograft Mineral and 25% autogenous bone chips obtained from the angle of the lower jaw (intraoral donor zone).

About the authors

Yulia Osipova

Saratov State Medical University

Author for correspondence.
Email: osipova-sgmu@mail.ru
ORCID iD: 0000-0002-0669-2867
SPIN-code: 6219-1210
Scopus Author ID: 6603352420
ResearcherId: Y-9513-2018

Doctor of Medical Sciences, Professor

Department of Therapeutic Dentistry

Russian Federation, Saratov, ul. Bolshaya Kazachya 112

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