Masyuk N.Y., Gorodetskaya I.V.
Thyroid status and structural and functional resistance of hard dental tissues
Vitebsk State Order of Peoples’ Friendship Medical University, Vitebsk, Republic of Belarus
Vestnik VGMU. 2017;16(2):97-105.
Objectives. To study the effect of iodine-containing thyroid hormones on the enamel resistance of the teeth of animals maintained on the cariogenic diet, subjected to stress and the combination of the indicated influences, as well as to estimate its mechanisms.
Material and methods. The study was performed on 130 mongrel male rats. There were groups of animals kept (1) on the diet of Stephen during 60 days, (2) in the overcrowded conditions (40 animals in the cage during the first month and 30 animals in the cage during the second one), (3) under the conditions of the combination of both factors influence. To simulate hypothyroidism thyreostatic mercazolil was administered to rats intragastrically in 1% starch paste: during the first 30 days in the dose of 25 mg / kg, during the next 30 days in the half dose. The introduction of L-thyroxin was performed in the same way in the close to physiological doses: from 1,5 to 3,0 mcg / kg during 28 days, then in the dose of 1,5 mcg / kg till the end of the experiment. Structural and functional stability of the hard dental tissues was estimated with the help of the enamel resistance test. The remineralization capacity of the saliva was assessed by its mineralizing potential and by the type of microcrystallization.
Results. It has been proved that hypothyroidism reduces the body’s resistance to stress, the small doses of L-thyroxin increase the resistance of the enamel under the influence of the cariogenic diet, stress, and their combination.
Conclusions. The dependence of structural and functional resistance of hard dental tissues on the iodine-containing thyroid hormones is connected with their influence on the mineralizing properties of the saliva (the decrease in hypothyroidism, and normalization under the influence of L-thyroxin) and its microcrystallization (the disturbance in hypothyroidism, the improvement under the action of the close to physiological doses of L-thyroxin).
Key words: iodine-containing thyroid hormones, stress, resistance, saliva, microcrystallization.
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Information about authors:
Masyuk N.Y. – postgraduate of the Chair of Normal Physiology, Vitebsk State Order of Peoples’ Friendship Medical University;
Gorodetskaya I.V. – Doctor of Medical Sciences, professor of the Chair of Normal Physiology, Vitebsk State Order of Peoples’ Friendship Medical University.