Dentist № 2 (49) – 2023, pp. 16-21                                                                                                             SCIENTIFIC PUBLICATION

Results of microhardness study at the reinforcing “tape-composite boundary”

N.V. Novaka, V.S. Starovoytovab

aMD, PhD, DMSci, Professor, Belorussian Medical Academy of Postgraduate Education, Minsk, Belarus
bBelorussian Medical Academy of Postgraduate Education, Minsk, Belarus

https://doi.org/10.32993/dentist.2023.2(49).4

ABSTRACT
Fiber splinting constructions are a combination of elements whose combined clinical effectiveness depends on the properties of each component separately and the nature of the connections between them. The studies proved that ribbon reinforcement increases the elastic modulus and bending strength of the adhesive splinting structure, and its failure occurs more often along the boundary of the splinting ribbon and composite material connection.
The aim of the study – study of microhardness indicators at the boundary “reinforcing tape – composite”, determination of optimal thickness of the layer of composite material covering the tape.
Objects and methods. 10 groups of 10 specimens of splinting structures, with different chemical composition of reinforcing tapes, 8 of which were made with the use of tapes based on an inorganic matrix, 2 – based on an organic one, respectively. 2 groups of 10 samples each with different thickness of the composite material layer covering the reinforcing tape: 0.2 mm, 0.3 mm, 0.4 mm and 0.6 mm.
Results and discussion. Among the studied splinting structures, the lowest microhardness index was in the group of specimens based on an organic matrix and was 49.76 kgf/mm2, the highest in specimens №1 based on an inorganic matrix – 72.74 kgf/mm2. The highest microhardness values were observed for both fiberglass-based and polyethylene-based tape samples with a maximum composite layer thickness of 0.6 mm and were 74.86 kgf/mm2 and 56.28 kgf/mm2, respectively. At the same time, the microhardness of the slits with a composite thickness of 0.2 mm was the lowest for samples based on the organic matrix and ranged from 39.98 kgf/mm2 to 42.36 kgf/mm2 with an average value of 40.96 ± 1.03 kgf/mm2.
Conclusion. Thus, the thickness of the composite material layer covering the reinforcing tape in the fabrication of splinting structures influences the resistance of the splint to mechanical impact, which is fundamental for reinforcing tapes based on an organic matrix (polyethylene) and insignificant for tapes based on an inorganic matrix (glass fiber). The high microhardness and negligible dependence on the thickness of the covering layer of the composite material can expand the indications for the clinical use of tapes based on an inorganic matrix (glass fiber).

Keywords: splinting construction, microhardness, thickness of the composite material layer

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Correspondence to:  Е-mail: zubnajafeja@yandex.by