EXPERIMENTAL AND MORPHOLOGICAL ASSESSMENT OF THE INFLUENCE OF HYDROXYAPATITE-CONTAINING OSTEOTROPIC MATERIAL AND ELECTRICAL STIMULATION ON REPARATIVE OSTEOGENESIS OF THE LOWER JAW.

OBJECTIVE: Aim: The aim of the study was to reveal the peculiarities of reparative osteogenesis in experimental lower jaw defect under the conditions of hydroxyapatite-containing osteotropic material application and electrical stimulation. PATIENTS AND METHODS: Materials and Methods: An experiment was conducted on 48 mature male rats of the WAG population. All animals were divided into 4 groups (12 animals in each group). Group 1 included rats that were not subjected to any manipulations. Group 2 included rats that were modeled with a perforated defect of the lower jaw body. Group 3 included rats that were modeled with a perforated defect similar to group 2, the cavity of which was filled with synthetic bone graft "Biomin GT" (RAPID, Ukraine). Group 4 included animals that were modeled with a perforated defect similar to groups 2-3, the cavity of which was filled with synthetic bone graft "Biomin GT". In animals of group 4, a microdevice for electrical action was implanted subcutaneously in the neck area on the side of the simulated bone defect. Morphological and statistical methods were used. RESULTS: Results: The research carried out by the authors proved that the use of the above-mentioned bone replacement material helps to increase the regenerative potential of the bone tissue of the lower jaw, but does not lead to the formation of a full-fledged bone regenerate, as evidenced by the results of the morphometry of the regenerate (the specific volume of lamellar bone tissue accounted for 54.9%); disordered localization of bone beams, which were characterized by reduced signs of mineralization; the presence in connective, osteogenic fibroreticular and lamellar bone tissues the encapsulated bone graft granules with the presence of inflammatory cell infiltration. In cases the combined use of synthetic bone graft "Biomin GT" and electrical stimulation, the authors noted more intensive reparative osteogenesis processes in the bone defect of the lower jaw compared to cases when only one bone graft was used, but they also did not lead to the formation of a full-fledged bone regenerate. CONCLUSION: Conclusions: The experimental and morphological study conducted by the authors proved that the use of hydroxyapatite-containing osteotropic material ("Biomin GT"), especially in cases of its combined use with electrical stimulation, significantly activates reparative osteogenesis in the bone defect of the lower jaw, which does not lead to the formation of a full-fledged bone regenerate.

MORPHOLOGICAL CHARACTERISTICS OF REPARATIVE OSTEOGENESIS IN THE RATS LOWER JAW UNDER THE CONDITIONS OF USING ELECTRICAL STIMULATION.

OBJECTIVE: Aim: The purpose of the study was to identify the morphological features of reparative osteogenesis in the rats lower jaw under the conditions of using electrical stimulation. PATIENTS AND METHODS: Materials and Methods: An experiment was conducted on 24 mature male rats of the WAG population. Two groups were formed. Group 1 included 12 rats that were modeled with a perforated defect of the lower jaw body. Group 2 included 12 animals that were modeled with a perforated defect similar to group 1. In animals, a microdevice for electrical action was implanted subcutaneously in the neck area on the side of the simulated bone defect (a temporary Videx AG 4 battery; a constant sinusoidal electric current of an unchanging nature 1 milliampere, frequency 30 W). The negative electrode connected to the negative pole of the battery was in contact with the bone defect. The battery and electrode were insulated with plastic heat shrink material. Morphological and statistical methods were used. RESULTS: Results: The positive effect of electrical stimulation on reparative osteogenesis was due to a decrease in the severity of hemodynamic disorders, activation of angiogenesis in granulation tissue, which was one of the components of the regenerate that filled the bone defect, matured and turned into connective tissue; stimulation of the proliferative potential of fibroblastic cells and cells with osteoblastic activity in granulation tissue; increasing the proliferative potential of osteoblastic elements of bone tissue bordering the cavity; stimulation of macrophage cells and processes of cleansing the bone cavity from fragments of a blood clot and alteratively changed tissues; formation of clusters of adipocytes in the loci of connective and granulation tissue of the regenerate; the process of metaplasia of connective tissue into bone tissue; an increase of the foci of hematopoiesis in the intertrabecular spaces of lamellar bone tissue. CONCLUSION: Conclusions: A comprehensive clinical and experimental study conducted by the authors proved that electrical stimulation activates the reparative osteogenesis in the lower jaw, which occurs through direct osteogenesis and does not finish on the 28th day of the experiment.

THE RELATIONSHIP OF CLINICAL AND MORPHOLOGICAL DATA IN COMMINUTED FRACTURES OF THE LOWER JAW.

OBJECTIVE: The aim is to establish the relationship between some clinical, physiological and morphological parameters in patients with the consequences of an acute injury considering the features of pathological and reparative changes in the bone fragments of the lower jaw formed during a fracture using clinical and morphological methods. PATIENTS AND METHODS: Materials and methods: The material of the study was bone fragments of the lower jaw, removed during osteosynthesis operations in 20 patients with traumatic comminuted fractures. Also, the material of the study was the data obtained during the examination of the above patients. Morphological parameters characterizing the state of the fragments tissues removed during surgical treatment of fractures of the lower jaw and clinical parameters characterizing the patient's condition in cases of traumatic fractures of the lower jaw treatment were identified for frequency and correlation analysis. Different of frequency of individual indicators' gradations cases was determined by the χ-square test, correlations between parameters (correlations of pairs of parameters "clinic - morphology", "clinical and laboratory data - morphology") - by calculating the Pearson association coefficient. RESULTS: Results: The main pathological and reparative changes are determined in the bone fragments of the lower jaw after a traumatic fracture: osteomedullary ischemic necrosis (traumatic bone infarction), nonspecific productive inflammation, endosteal and periosteal bone regenerates. The severity and frequency of pathological and reparative changes in the bone fragments of the lower jaw vary, leading to various correlations between clinical and morphological indicators of the fragment tissues conditions. Reliable correlations were established between individual clinical and morphological indicators of the state of bone fragments corresponding to the values of the association coefficient in the range of 0.3-0.7, in particular: in the pair "age of the patient" - "endosteal regenerates" - the dependence is negative, of medium strength, significant (p<0.05); in the pair "age of the patient" - "periosteal regenerates" - the dependence is negative, of medium strength, significant (p<0.05); in the pair "fragment surface area" - "osteonecrosis" - the relationship is negative, weak, significant with the probability of error in assessing the value |ra| p<0.1; in the pair "locus of a fracture in the lower jaw" - "type of inflammation in the bone marrow" - the dependence is positive, of medium strength, highly reliable (p<0.01). CONCLUSION: Conclusions: A comprehensive clinical and morphological examination made it possible to calculate quantitative data that characterize the frequency parameters of the occur¬rence of certain pathological changes in the bone fragments of the lower jaw after a fracture and the features of individual clinical and morphological parameters conjugation in patients with the consequences of a mechanical jaw injury. The obtained data on the correlation dependences of the type "clinic - morphology" can be used to predict the severity of morphological parameters according to the known values of clinical parameters in patients with the consequences of mandibular fractures.