An Assessment of the Effect of Chemical Impregnation on the Tensile Strength of Gingival Retraction Cords Associated with Scanning Electron Microscopic Evaluation
Citation Information :
Madhok S, Kumaraswamy K, Madhok S. An Assessment of the Effect of Chemical Impregnation on the Tensile Strength of Gingival Retraction Cords Associated with Scanning Electron Microscopic Evaluation. Arch Craniofac Sci 2013; 1 (6):64-66.
Background & Objectives: Gingival retraction may damage the sulcular tissues irreversibly. Cord tearing during insertion or removal results in shreds being left behind within the gingival sulcus and supra-alveolar connective tissue. This has been attributed to the deficient tensile strength of the cords. It is crucial that retraction cords have satisfactory physico-chemical properties. There is much speculation in literature regarding the effect of hydration, types of cords, diameters of cords, effect of different chemical impregnating agents, variations in the concentrations of impregnating agents and the time for which cords are immersed in them, on the physico-chemical properties of retraction cords. The aim of this study is to assess the effect of chemical impregnation and its concentration variation on the tensile strength of cords & simultaneously evaluate its effect on the ultrastructure of cords using a scanning electron microscope (SEM).
Methods: 105 specimens of braided standard cotton cord each 10 centimeters in length were cut and randomly allocated to 7 groups (15 in each group). Specimens from Groups I to III and Groups IV to VI were impregnated with varying concentrations of Aluminium Sulfate (AS) and Ferric Sulfate (FS) respectively. Group VII was the control group. Each specimen was then subjected to tensile loading in an Instron machine and the readings when the specimens failed were recorded. Additional 2 specimens per group were taken for SEM Evaluation.
Results: The effect of impregnating agent and its concentration variation were analyzed by intra and inter group comparisons. Control group had maximum tensile strength & Group VI had minimal tensile strength. AS and FS impregnation led to a significant decrease in tensile strength of the specimens.
Conclusion: Within the limitations of this study, chemical impregnation negatively affects the ultrastructure of the retraction cords by reducing their structural integrity thereby hampering their physico- mechanical properties and weakening them.
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