Втрати інтенсивності світлового потоку світлодіодного фотополімеризатора в скловолоконних армуючих елементах

Abstract

У роботі представлені результати лабораторного дослідження втрат інтенсивності світлового потоку світлодіодного фотополімеризатора в скловолоконних армуючих балках різної товщини і оптичної щільності адгезивних мостоподібних протезів. За застосування двох прозорих балок максимальною товщиною 2,8 мм втрати складають менше половини від вихідного рівня, у разі використання балки білого кольору товщиною 1,0 мм втрати сягають більше 90%.; В работе представлены результаты лабораторного исследования потерь интенсивности светового потока светодиодного фотополимеризатора в стекловолоконных армирующих балках различной толщины и оптической плотности адгезивных мостовидных протезов. При применении двух прозрачных балок максимальной толщиной 2,8 мм потери составляют менее половины от исходного уровня, в случае балки белого цвета толщиной 1,0 мм потери превышают 90%; The aim of the study is laboratory investigation of the light intensity losses of led photopolymerization in reinforcing elements of the bonded bridges. Object and methods of investigation. Fifty samples, which represent the fragments of glass-fibre reinforcing elements (bars having different thickness and optical density) were divided into five groups to study the light intensity losses of led photopolymerization. The laboratory study was carried out using the experimental unit. The bar samples were placed into the unit pocket between the source of light and sensing device. The light guide of dental curing light unit with the initial intensity level 1500 mW/cm2 was used as a source of luminous flux. The intensity of the light flux without sample was evaluated, the rate was taken as 100%, then the samples were placed into the unit pocket and evaluation of intensity was carried out again. The losses were determined in percent from the initial level. Results and their discussion. The maximum index of intensity losses in the luminous flux of led photopolymerization was registered in the samples of the glass-fibre white color bar with the thickness 1.0 mm (I group) – 91.93±0.41% (p<0.05). The obtained index was almost nine times more than minimum indicator of intensity losses, which was registered in the samples of transparent glass-fibre bars with the thickness 0.7 mm (II group), – 10.76±0.24% (p<0.05). The increase in the thickness of the same bar samples in two times to 1.4 mm (IV group) caused the significant (p<0.05) increase of losses almost in two times – to 18.58±0.19%. Transparent bar samples of the same thickness, consisted of two fragments connected by fluid nanophotocomposite (III group), have represented losses at level 24.31±1.01%. The significant (p<0.05) difference between the last two indicators, probably is caused by the presence of fluid nanophotocomposite layer in III group samples and losses of light intensity on the connecting edge between the nanophotocomposite layer and glass-fibre bars. If the fragments of transparent glass-fibre bars with the thickness 1.4 mm (V group samples) were connected by nanophotocomposite, the losses significantly (p<0.05) increased in comparison with III group samples almost in 2 times – to 41.11±1,15%. In case of two transparent bars application with the total thickness 2.8 mm in bonded bridges construction, the intensity losses of the light flux does not reach even the half of initial level in 1,500 mW/cm2. However, the initial intensity shoul be higher, if the glass-fibre bar even with minimum thickness of 1.0 mm, but white color was used as reinforcing element. Conclusions. Thus, in case of reasonable choice of the glass-fibre reinforcing elements for the optimal bonded bridges construction manufacturing it is necessary to consider the degree of bars optical density and their thickness, and also dependance on the estimated intensity losses of the light flux which can be determined according to the results of conducted study, to choose the source of the light flux, that is led curing light unit, with necessary initial intensity to ensure the sufficient degree of restorative material hardening.