[Hydrodynamics of dental dentinal fluid]. / Gidrodinamika dentinnoi zhidkosti zuba.

BACKGROUND: Dentinal fluid is very close in its physical and mechanical properties and composition to blood plasma, which makes it a potentially aggressive biological environment for modern adhesive systems. An in-depth study of the physiological processes of the functioning of tooth dentin remains relevant in order to solve problems associated with its artificial restoration. PURPOSE OF THE STUDY: Study using computer simulation speed of movement and pressure distribution of dentinal fluid in the dentinal tubule of the tooth to assess the possibilities of their regulation. MATERIAL AND METHODS: To model the distribution of flow velocity and pressure of dentinal fluid in the dentinal tubule, the finite element method (Fluent ANSYS computer program) was used. RESULTS: Immediately behind the spherical tip of the odontoblast, there is a rapid increase in the hydraulic diameter of the flow section of the dentinal tubule, and, accordingly, a decrease in capillary pressure, while the tip of the odontoblast creates a large local hydraulic resistance. The resulting distribution of pressure drop in the damaged dentinal tubule is consistent with the fact that fluid movement is due, to a greater extent, to the capillary effect rather than the inlet pressure into the dentinal tubule. CONCLUSION: By changing the length of the odontoblast process, it is possible to influence the parameters of the hydrodynamics of dentinal fluid in the space of the dentinal tubule.

[Clinical analysis of the cleaning effectiveness of toothbrushes of various types in children aged 6-15 years after a single brushing]. / Klinicheskii analiz ochishchayushchei effektivnosti zubnykh shchetok razlichnogo tipa u detei 6­15 let posle odnokratnoi chistki zubov.

OBJECTIVE: The purpose of the study is to conduct a comparative analysis of the cleaning effectiveness of toothbrushes of various types in children aged 6-15 years after a single tooth brushing. MATERIAL AND METHODS: A parallel, randomized, open clinical trial was conducted aimed at evaluating the effectiveness of toothbrushes of various types in children aged 6-15 years. The study involved 180 children of both sexes aged 6-15 years, who were divided into 3 age categories: 6-8 years (n=60), 9-11 years (n=60) and 12-15 years (n=60). In each age category, 3 groups of 20 people were randomly formed who received toothbrushes of different types: groups I, IV and VII - a manual brush with a multi-level brush field, groups II, V and VIII - a manual brush with an even brush field, groups III, VI, IX - an electric brush with the technology of reciprocating and pulsating movements. After the dental examination, the children were taught the standard method of brushing their teeth. The cleaning efficiency of toothbrushes was evaluated using the hygiene index PI (S. Turesky, 1970) before and after a single tooth brushing. The nonparametric Wilcoxon test was used to compare the indicators of one group in dynamics, and the Mann-Whitney test was used to identify differences between groups. RESULTS: A comparative analysis showed that the efficiency of the electric brush in all age groups was significantly higher compared to manual brushes having an even brush field, and in children 12-15 years old it was higher compared to both manual brushes. In the age groups of 6-8 years and 9-11 years, a manual brush with a multi-level brush field, intersecting tufts of bristles and a power projection showed high cleaning efficiency, which did not significantly differ from the indicators of plaque reduction after using an electric brush (Mann-Whitney criterion, p>0.05). CONCLUSION: An electric toothbrush is the most effective means of oral hygiene in children. In children aged 6-8 years, a high cleansing effect was achieved with a manual brush having a multi-level brush field. In the hygienic education of children of this age, it is necessary to pay more attention to the formation of the correct technique of brushing teeth with the help of manual brushes corresponding to age characteristics.