ОРТОПЕДИЧНА СТОМАТОЛОГІЯ

. According to the results of the study, it was found that out of 86 patients examined, 44 patients (51.16%) of both groups used soldered bridges, 42 (48.84%) - full-cast bridges. Pathological manifestations of the negative effects of soldered dentures in the oral cavity and gastrointestinal tract were detected in 41 of 44 patients, which is 47.7% of the total number of patients examined. Out of 42 patients (48.84%) in both groups, 11 (12.8%) had full-cast bridges. Soldered bridges cause 35% more complications in the oral cavity and digestive system than full-cast dentures. Negative manifestations and exacerbation of somatic pathology when using fixed dentures are observed 3 times more often in patients with hyperacid gastritis.


Background
The full-arch restoration and total tooth loss are the most important issues of specialized dental care for the population. Prosthetic treatment not only eliminates aesthetic deficiencies and restores the impaired function of the dentoalveolar system but also has significant preventive value in prophylaxis of gastrointestinal diseases [2].
The issue of the interaction between oral cavity tissues and various types of dentures is one of the key concerns in prosthodontics. The use of different types of dental prostheses is an intervention that alters the biological equilibrium in the tissues of the oral cavity and the body as a whole, especially in the case of fixed dentures. The extent and nature of these changes depend on several factors, such as the patient's overall somatic condition, the construction material used for the denture, the prosthetic manufacturing technology, etc. [1].
The materials used for dental prostheses and the technologies for their application are constantly being improved. However, according to literature data, the incidence of complications after prosthetics remains relatively high [6,12,13]. Most state-ofthe-art construction materials for different types of dental prostheses are not biologically inert to the human body. As a result, in 4-11% of cases, patients experience unpleasant sensations that, in terms of intensity, become the cause of intolerance to dental prostheses. The presence of somatic pathology in the gastrointestinal tract further exacerbates the situation. The analysis of the literature sources has found that wearing dentures causes an increase in pathological manifestations not only in the tissues of the oral cavity but also in complications affecting the tissues of the gastrointestinal tract [2,7,9].
The oral cavity and its mucous membrane are the first link in the human digestive system and come into direct contact with dental prostheses. The processes of absorption also start in the oral cavity and then continue in the esophagus, stomach and intestines. Therefore, ions that enter the oral fluid from the dentures to some extent reach various sections of the gastrointestinal tract and have a certain impact on the condition of the gastric and intestinal mucosa [2,8].
Our analysis of domestic and foreign studies shows that different types of dental prostheses made from various dental materials can cause three main types of pathological effects on the tissues and organs of the oral cavity and certain organs and systems of the human body, namely, chemical-toxic, electro-galvanic (damage caused by galvanic current) and allergic effects [3,10]. Some authors, based on specific clinical cases of intolerance to dental materials, argue for the need to examine potential wearer of fixed dentures for compatibility not only with construction materials but also with materials used for retaining such prostheses [12].
In prosthodontics, a wide range of construction materials is used for manufacturing the fixed bridges, including stainless steel alloys, ceramic masses, zirconia, polymer materials, and others. The reason for the development of pathological impact of metal materials in dental prostheses on the condition of the oral cavity is the release of metal alloy ions into saliva [5].
O.I. Roschuk conducted research on the negative consequences of metal and metal-containing fixed dentures on the status of protein-carbohydrate components, oxidant-antioxidant and cytokine homeostasis in patients with duodenal ulcer disease. The author states that the use of fixed dentures made of metals exacerbates somatic pathology, therefore, the further development of effective programs for pathogenetic correction of the adverse ef-fects of metal and metal-containing fixed dentures on the recurrence of duodenal ulcer disease is relevant. This is especially important considering the progressing tooth loss [11].
Electrochemical corrosion in the oral cavity not only causes changes in the tissues of the oral cavity but also leads to alterations in the immune and enzymatic systems of the body. Corrosion products from stainless steel alter the activity of enzymatic systems in saliva, blood and the immune defense of the mucous membranes throughout the gastrointestinal tract [10].

Purpose
The study aimed at investigating the impact of fixed dental prostheses made from different construction materials on the tissues of the oral cavity and the gastrointestinal tract in chronic gastritis.

Methods and Material
We examined patients from the gastroenterology unit who were admitted for inpatient treatment for chronic gastritis and were using fixed dental prostheses. A total of 86 patients were included in the study.
Prosthetic treatment and the conduct of planned research were carried out in all patients with their informed consent for such treatment and further participation in the study in accordance with the Helsinki Declaration of the World Medical Association regarding ethical principles for medical research involving human subjects [4].
During the examination, we took into account complaints of burning sensation, itching, redness of the gingival mucosa, gingival swelling, increased salivation or dryness in the oral cavity, heightened perception of acidity and the presence of microcurrents in the oral cavity.
During the objective examination, we took into account the type of denture and visually determined the material from which it was made. We also considered the type and number of abutment elements, the compliance of the denture with clinical and technological requirements, the duration of its wearing and the diagnosis of the underlying disease for which the patient was undergoing hospital treatment. Based on these criteria, the patients were divided into groups and subgroups. Group 1 (n=49) involved patients with chronic hyperacid gastritis, while Group 2 (n=37) included patients with chronic hypoacid gastritis. In each group, two subgroups were identified: subgroup A comprised patients wearing fixed soldered bridges and subgroup B comprised patients wearing full-cast bridges.
In all patients, a complete blood count was performed. For the analysis of the oral fluid content of microelements, the samples were collected and examined. To detect elements from the prosthetic materials, a biochemical analysis of gastric juice and urine was conducted using the ionometric method.

Results and Discussion
The objective examination has found that 22 patients of subgroup A, Group 1, were using fixed sol-dered bridges with titanium nitride coating and acrylic resin veneering. The average duration of wearing dentures was 6±1.35 months. 13 out of 22 patients complained of gum itching, burning sensation, dryness in the oral cavity and increased acidic taste; 4 patients reported itching of the cheek mucosa in contact with the plastic veneering. Laboratory tests revealed metal "intolerance" in 9 patients of this subgroup, which accounted for 40.9%. Allergic stomatitis caused by acrylic veneering was diagnosed in 4 patients (18.2%) of subgroup A. 5 patients of subgroup A, Group 1, complained of the occurrence of microcurrents in the oral cavity, increased salivation and irritability. Based on the results of the objective examination and laboratory tests, galvanic phenomena were identified in these patients.
It should be noted that 18 patients of subgroup A experienced exacerbation of their underlying disease following the first month of wearing dentures.
During the objective examination, it was determined that 3 patients of subgroup B, Group 1, were using full-cast bridges, 5 patients were using fullcast dentures with acrylic resin veneering and 19 patients were using full-cast metal-ceramic bridges. The average duration of wearing dentures in this subgroup was 15±2.46 months.
Patients who were using full-cast metal bridges (3 individuals, 11.1%) did not have any complaints. Among the 5 patients (14.8%) using full-cast dentures with acrylic resin veneering, 4 of them reported gum swelling around the denture, occasional pain, unpleasant odor and burning sensation. Out of the 19 patients (70.3%) who had been using fullcast metal-ceramic fixed dental prostheses, 4 patients (14.8%) experienced complaints of gum itching, burning sensation of the mucous membrane and discomfort while chewing and at rest. Objective examination revealed hyperemia and swelling of the gingival mucosa at the dentures.
In the patients of Group 2, subgroup A, out of 22 patients (59.45%), 9 patients (24.3%) had complaints of oral burning sensation, dryness and changes in taste; 7 patients complained of gum itching, increased perception of acidity, occasional occurrence of electric currents, especially during eating. 6 patients of this subgroup did not have any complaints. The average duration of wearing dentures in this subgroup was 10 ± 1.44 months.
Out of the 15 patients (40.5%) of subgroup B, 12 patients (32.4%) used full-cast metal-ceramic bridges, and 3 patients (8.1%) used full-cast metal dentures. Only 3 patients of this subgroup had complaints, including swelling of the mucosa at the dentures, discomfort during chewing, deterioration of taste sensation, and occasional occurrence of oral burning sensation. The average duration of wearing dentures in subgroup B was 18±1.64 months.
Along with complaints related to wearing dentures reported by patients in both groups, deteriorations in overall well-being related to the underlying disease and changes in blood and gastric juice parameters were also observed.
To eliminate complications associated with wearing dentures, patients of both groups who had the most pronounced pathological symptom complex and laboratory confirmation were offered repeated prosthetic treatment. This was especially recommended for all patients of subgroup A of both groups who were using soldered bridges.
In patients who received treatment for their underlying disease of the gastrointestinal tract without elimination of heterogeneous metals from the oral cavity and removing soldered bridges with titanium nitride coating, a significant increase in the amount of manganese, nickel and lead was found in the gastric juice. Additionally, higher levels of iron and copper were detected in the urine.
In individuals who previously underwent prosthetic treatment with replacement of dental constructions, taking into account their individual characteristics in the choice of prosthetic materials, a decrease in the number of microelements in the gastric juice and urine was observed. 2. Out of the 42 patients (48.84%) of both groups who used full-cast dentures made of various construction materials, 11 patients (12.8%) experienced certain problems.
3. Soldered bridges during their wearing cause by 35% more complications in the oral cavity and digestive organs compared to full-cast dentures.
4. Patients with hyperacid gastritis experience negative manifestations and exacerbations of somatic pathology by 3 times more frequently when using fixed dentures.

Perspectives of further research
The scientific data obtained from observations regarding the negative impact of the fixed dentures on the tissues of the oral cavity and the gastrointestinal tract require the follow-up in-depth and comprehensive study of pathological lesions to develop mechanisms for their prevention.