Go for xray to determine the extent of tooth decay. Go to a proper dental clinic,don’t look for cheap dental treatment facilities/options. At your age you require best dental treatment that lasts for years and years.

If your teeth have become black and rotten from the inside, it is crucial to seek professional dental care as soon as possible. Tooth discoloration and decay can be caused by various factors, such as poor oral hygiene, diet, tobacco use, or underlying dental conditions. Here are some steps you can take: Visit a Dentist: It's essential to consult a dentist who can accurately diagnose the condition of your teeth and provide appropriate treatment options. They may recommend fillings, root canal treatment, or other dental procedures based on your specific situation. Practice Good Oral Hygiene: Brush your teeth twice a day using a fluoride toothpaste and a soft-bristled toothbrush. Floss daily to remove plaque and debris from between your teeth. Consider using an antimicrobial mouthwash as well. Avoid Tobacco and Limit Staining Substances: Smoking and chewing tobacco can contribute to tooth discoloration and decay. Additionally, limit your intake of foods and beverages that are known to stain teeth, such as coffee, tea, red wine, and sugary or acidic drinks. Follow a Healthy Diet: Eat a balanced diet rich in fruits, vegetables, whole grains, and lean proteins. Minimize your consumption of sugary and acidic foods, as they can contribute to tooth decay. Professional Teeth Cleaning: Schedule regular professional teeth cleanings to remove plaque, tartar, and surface stains. This can help improve the appearance of your teeth and prevent further decay. Remember, every dental situation is unique, and the best course of action can only be determined by a qualified dentist after a thorough examination. It's important to follow their advice and maintain regular dental check-ups for optimal oral health.

Hello Plz share pic of that

Hi. Could you please attach a pic along for better suggestion.

These deposits are of tartar, plaque and stains that need to be removed from the teeth. Visit a dentist/ periodontist and get professional cleaning done.