The dissertation for a Candidate Degree in Medical Sciences in specialty 14.01.22 “Dentistry”. – Shupyk National Medical Academy of Postgraduate Education, Kyiv, 2020.
The thesis is devoted to the morphofunctional substantiation of minimally invasive metallic osteosynthesis of the mandibular fractures, by creating of an anatomically functional titanium plates for the osteosynthesis of angular and medial mandibular fractures, as well as the development of a technique for optimizing the plates by taking into account the action vectors of the muscular apparatus of the mandible and osteoporotic changes in it.
The thesis is performed in accordance with the scientific research plan of the Department of Pathological Anatomy of the Medical Institute of Sumy State University «Investigation of bone changes in fractures when using nanomaterials for metallic osteosynthesis, taking into account the function of the muscular system», (state registration number №0116U006815), 2016.
Based on the morphological examinations performed on the bone tissue of the mandible, it was concluded that pathological changes in it can be considered as risk factors for postoperative complications in patients. On the other hand, studies of the surface properties of titanium plate samples showed a positive correlation between their surface roughness and microorganisms.
Computer modelling was used to design various configurations of titanium plates for osteosynthesis of both angular (π-shape, Y-shape, straight and square plates) and medial (segment plates, plates in the form of type I and type II bones) mandible fractures taking into account vector tractions of masticatory muscles and morphological changes in the bone tissue. The stress-strain analysis of the titanium plates enabled us to conclude that π-shaped plates and plates in the form of type I bone are the most efficient to satisfy all the set objectives.
The clinical study indicated that most patients admitted to the Department of Maxillofacial Surgery with mandible fractures were male. Fractures of the mandible were most common in the most able-bodied part of the population aged 20 to 30 (45,0 %). The majority of the patients were unemployed (52,5 %). Data on hospital admissions indicate that 32,5 % of patients were admitted for treatment after more than 72 hours and the vast majority of them had no temporary transport immobilization.
In our study, all patients in both groups had a unilateral mandibular fracture. The functional loading in each group was restored within 2–5 days after osteosynthesis surgery. We also identified that most of the injuries were associated with outdoor traumas (42,5 %).
After the osteosynthesis surgery, an uncomplicated postoperative course was observed in 15 patients from the first group and in 18 patients from the second group, which is 75 % and 90% respectively.
Furthermore, our study showed the duration of inpatient treatment was consequently decreased to 8,3±0,57 bed days in the second (index) group against 9,2±0,56 bed days in the first (control) group.
Key words: angular mandibular fracture, medial mandibular fracture, osteosynthesis, computer modelling, finite element method, stress-strain state, titanium plates, microbial adhesion, the force of masticatory muscles.
