Bristle end rounding of manual toothbrushes and reproducibility of end rounding classification.

Purpose: To evaluate the bristle end rounding quality of the toothbrushes selected. Furthermore the reproducibility of the bristle tip classification method was assessed.

Methods: Fifteen different manual toothbrushes were examined by taking into account the traumatic potential of toothbrushing caused by sharp and edged bristle end geometry.

[Overfilling into the mandibular canal as an endodontic complication. A review].

As a consequence of traumatic and toxic injury of the inferior alveolar and the mental nerves, disturbances of sensibility may develop during and after root canal treatment. Several reasons are possible. In most cases, however, such disturbances are the result of root canal filling materials that have been pressed into the mandibular canal.

[Bristle anchoring and bristle end-rounding in adults' toothbrushes].

Scanning electron microscopic study of bristle heads of 8 toothbrush brands commercially available in the Federal Republic of Germany and Switzerland has shown qualitative variations in the rounding of bristle ends. The percentage of acceptable end rounding of the bristles was for 4 brands above 75% and for 2 brands 55-56%. For 2 products, the percentage was below 40%.

[SEM study and clinical observations of "Turner teeth"].

The altered structure of "Turner-teeth" was examined under the scanning electron microscope. The enamel surface revealed developmental disorders such as bowl-shaped pits, Tomes' process pits and enamel craters with rounded borders. On the fractured surfaces of yellowish discolored enamel, localized islands of pathological enamel were found.

[Electron microscopic research on the structures of exposed cementum].

In this study the ultrastructure of exposed cementum just below the cemento-enamel junction was investigated. In a surface layer of exposed cementum measuring up to 4 microns in depth, newly formed crystallites were observed. These crystallites were 660-1800 A long and 130-260 A thick.

[Bristle end rounding and anchoring in children's toothbrushes].

This scanning electron microscopic study of eight toothbrushes for children has shown differences in quality and quantity of the rounding of bristle ends. While four products which were examined for the first time were partially deficient, the preparation of the other toothbrushes had clearly improved in comparison to previous products. Quotas of acceptable end rounding of the bristles varied considerably between 14.

Ultrastructure of the predentinal-dentinal border zone of human teeth exposed to basic chromium (III) sulfate. A method for contrasting of collagen fibrils.

An electron microscopic investigation was undertaken to study a method for contrasting predentine collagen fibrils by their cross-striations after exposure of tissue to chromium solution for various periods. After 1 day of treatment, the cross-striations of collagen fibrils in predentine were clearly visible. The contrast of the cross-striations increased with longer periods of exposure to chromium.