ISO 8627

Significance

Stiffness in the bristles is one of the most important properties of a toothbrush that can either enhance or reduce its overall effectiveness in cleaning the teeth and ensuring their safety. Stiff bristles can harm the gums and wear out the enamel, and soft bristles can be ineffective for plaque removal. International Standard (ISO) 8627 set the rules for an internationally recognized system of objectively determining toothbrush stiffness, which to date has been used to communicate the relative performance of toothbrushes between manufacturers and regulators. The three-tier system (soft, medium, hard) became a commercial norm that remains in effect for labeling toothbrushes and setting consumer expectations today worldwide.

Scope

ISO 8627 applies to conventional manual toothbrushes and provides the relevant information concerning testing machines required for objective stiffness evaluation of the tufted area. The standard establishes a structured grading scheme that classifies toothbrush bristle stiffness into three categories—soft, medium, and hard—giving manufacturers a clear, standardized framework for product characterization and quality control. Presto's precision force testing instruments are well-suited to the load measurement and deflection assessment demands of this standard, enabling toothbrush manufacturers and testing laboratories to determine bristle stiffness with accuracy, repeatability, and confidence.