TEMPERATURE-DEPENDENCE OF TOOTHBRUSH BRISTLE MORPHOLOGY - AN ULTRASTRUCTURAL-STUDY

In this study, it was demonstrated that the original forms of toothbru sh bristle ends undergo morphological changes during the preparatory p rocedures required prior to their examination by scanning electron mic roscopy (SEM). In particular, the distance of the specimens from the c athode of a traditional sputter-coater and the time of gold-palladium coating influence the temperature inside the vacuum compartment. Morov er, the temperature influences the original morphology of toothbrush b ristles. 2 segments of each toothbrush head with nylon or ultralon bri stles were cut off the brush: one was mounted vertically and one horiz ontally on stubs for SEM analysis. Different temperatures were measure d inside the sputter-coater at the level of the bristle ends, during c oating with gold-palladium alloy. The temperature at the level of the bristles that were placed horizontally was about 38 degrees C, and 59 degrees C when they were placed vertically. SEM analysis of the specim ens showed that the same toothbrush has end-rounded bristles at about 59 degrees C and non-acceptable irregular bristles at about 38 degrees C. Retraction of bristles (which appeared shortened and with increase d diameters) and superficial cracks were particularly present in the v ertically placed ultralon bristles.