Effects of ultraviolet irradiation equipment on endodontic disease–related bacteria

Considering the particular danger of remote skin reactions to ultraviolet irradiation (UVI), it is advisable to use ointments with antioxidant activity to reduce its negative effect on the skin. The rationale for the choice of ointments with antioxidant activity was the fact that they reduce the damaging effect of ultraviolet radiation in the erythemal and early post-erythemal period. The presence of a regular connection between the development of the early and late periods has given reason to assume the protective effect of ointments on the remote skin reactions. Objective: to study the effect of thiotriazoline ointment and thiotriazoline ointment with silver nanoparticles on the state of the morphological structures of the skin of guinea pigs after local UVI. Material and methods of research. The study involved 132 albino guinea pigs weighing 400-500 g, divided into 4 groups: 1 - intact, 2 - control (guinea pigs subjected to local UVI), 3 and 4 main ones. The third main group included guinea pigs that after UVI were administered thiotriazoline ointment in the treatment and prophylactic regime, the fourth main group included guinea pigs that after UVI were administered thiotriazoline ointment with silver nanoparticles in the same mode as Group 3. Ointments were applied 1 hour before irradiation and daily until erythema disappeared. Ultraviolet erythema was caused by irradiation in 1 minimum erythemal dose. After 2, 4 hours, on the 3rd, 8th, 15th, 21st, 28th day, the fragments of irradiated skin were investigated using histochemical and morphometric methods (fibroblast density and epidermis thickness). Results. Morphological changes in the skin after applying ointments with antioxidant activity were unidirectional. It was revealed that in the early periods after irradiation, thiotrazoline ointment and thiotrazoline ointment with silver nanoparticles do not affect changes in the thickness of the epidermis, but statistically significantly reduce the density of fibroblasts in the dermis on the 3rd day of the experiment compared to the control group. In the later periods, under the influence of thiotriazoline ointment, a gradual decrease in the thickness of the epidermis, which reached the norm by the end of the experiment, was observed. On the 8th day, the maximum density of fibroblasts was recorded, in the subsequent periods of the experiment, the index gradually decreased, which was accompanied by collagenization of the papillary layer in the loci of damage to collagen and elastic fibers detected in 50% of cases. In later times, under the influence of thiotriazoline ointment with silver nanoparticles, the processes of restoring the morphological structures of the skin occurred faster. In parallel with the decrease in the density of fibroblasts in the loci of the previous damage to the collagen and elastic fibers of the papillary layer, thickening of collagen fibers was observed, replacing them with segments of destruction of elastic fibers. In this group, at the end of the experiment, the collagenization locus was small, single, occurring in 16.7% of cases. Conclusions Ointments with antioxidant activity exert a positive effect on the state of morphological structures of the skin, damaged as a result of local UVI, in erythemal and post-erythemic periods. In the early periods after the local UVI, there was a general tendency for the effect of both ointments, as they reduced the density of fibroblasts on the 3rd day, but did not result in complete normalization. In the late period after local UVI , under the influence of thiotriazoline ointment and thiotriazoline ointment with silver nanoparticles, thickness of the epidermis (by 21st and 15th day, respectively) and density of fibroblasts (by the 28th day) decreased to normal while without treatment both indicators exceeded the norm by several times for 28 days of the experiment.

Download Full-text