Choosing your bristles softness/hardness
The question of the most desirable bristle hardness is not settled. Bristle hardness is largely dependant on the diameter of the bristles. The diameter of bristles are normally 0.15mm (extra soft), 0.2mm (soft), 0.3mm (medium) and 0.4mm (hard). Toothbrush manufacturers have minor changes to these dimensions based on their overall brush design and market strategy.
Additional parameters that finally determine the hardness of the bristles in a brush depends on the length of the bristle, number of bristles in each tuft, flexibility of the material used to make bristles and quality of trimming/polishing of the bristle ends.
The choice of bristle hardness depends on the teeth health, age of the person, brushing habits and also the region where it is being used.
Soft or medium bristles are ideal choice as the hard bristle cause damage to the teeth as well as the gums, especially on vigorous brushing and the extra soft bristles just don’t cleans the teeth with proper efficacy.
For adults in D&E markets such as India, soft or medium bristles are suitable for everyday use. In developed markets, preference is to use either extra soft of soft bristles. For children, extra soft bristles are recommended.
Your choice depends on your specific dental needs and what feels more comfortable for you. It is always better to get advice from your dentist when you visit them. Until your next visit to the Dentist, it is safer to use either soft or medium bristles. In a recently conducted survey, user preferences were 44% for medium, 40% for soft, 13% for extra soft and mere 3% for hard bristles.