Can yellow teeth become white again by brushing after not brushing for a long time?

Extrinsic tooth discoloration caused by prolonged lack of brushing can often be resolved through cleaning and proper oral hygiene. However, if it has progressed to intrinsic discoloration, simply brushing teeth is unlikely to improve the condition, and professional treatment will be necessary. It is recommended to visit a hospital promptly for appropriate examinations to assess your health status and follow medical advice for proper management.

Not brushing teeth for an extended period allows food debris, dental plaque, and tartar to accumulate on the tooth surface, leading to extrinsic staining and yellowing of teeth. In such cases, consistently brushing with fluoride toothpaste, using dental floss to clean between teeth, and employing interdental brushes 1–2 times per week to remove plaque can gradually restore the natural color of teeth within 1–2 weeks. If tartar buildup is significant, professional scaling at a hospital or dental clinic should be performed first, followed by routine oral care to maintain whitening results.

If tooth discoloration persists for a long time, external pigments may have penetrated deeply into the enamel. Additionally, chronic plaque irritation may lead to pulp necrosis, causing internal tooth discoloration. In these cases, daily brushing cannot remove deep stains, and tooth color cannot be improved through routine cleaning alone. Professional treatments such as in-office whitening (e.g., cold light bleaching) or dental veneers are required to restore a white, bright smile.

For daily care, it's important to establish a regular tooth-brushing habit and avoid prolonged neglect of oral hygiene. Limit consumption of substances that promote staining, such as coffee, strong tea, and tobacco; rinse your mouth promptly after consuming them. Schedule dental check-ups and professional cleanings every six months to one year to prevent recurrence of tooth discoloration and maintain both the health and appearance of your teeth.