Our mouth plays host to colonies of bacteria that are generally beneficial to us, chiefly by aiding in the initial process of digestion or protecting the teeth and gums. Such microorganisms are known as probiotics. However, there are many other types of bacteria that cause damage to the gums and teeth, leading to a variety of dental disorders such as plaque buildup, tooth decay, gum disease, and periodontitis. Such bacteria thrive on food particles in the mouth (particularly sugary and starchy foods) and form corrosive acids that eat away the teeth and affect the gums.

The National Institutes of Health informs that sticky carbohydrate-loaded foods (bread, candies, and dried fruits) are the worst enemies of the teeth, since they cling on to the teeth for longer time periods and eat away the outer protective layers of the teeth. Also, frequently munching on some snacks or sipping sodas as a routine is not a recommended practice. Children oftentimes tend to keep food in their mouths for longer time without swallowing them, which can also cause tooth decay. 

Some of the foods that damage your teeth include: 

• Food, such as bread, and snacks, such as chips, cookies, lollipops, and candies, which stick to the teeth and gums
• Sodas (including diet sodas) and other carbonated frizzy drinks: These contain acids that eat away the enamel of the teeth, leading to tooth enamel loss
• Fruit juices of lemon, orange, and lime that are rich in citric acid
• Food and drinks, such as alcohol and caffeinated beverages, that cause the mouth to dry up (reduced saliva quantity in the mouth). Dry mouth can be caused by aging or certain health conditions and can be aggravated by spicy or salty foods
• Chewing on ice cubes, or other such hard substances, like candy, regularly can injure the teeth

Oral bacteria that cause tooth decay and cavities cannot be eliminated from the mouth; however, they may be controlled and managed by regularly cleaning the mouth after eating any meal and practicing good dental hygiene. The prevention of plaque and tartar buildup in the mouth that lead to tooth cavities and other dental diseases may be undertaken by maintaining oral hygiene, using fluoride dental products (toothpastes and mouth rinses), avoiding starchy and sugary foods (which are the worst foods for your teeth), undertaking regular visits to the dentist, and eating foods that are good for the teeth and promote healthy bacteria in the mouth.

References:

Bader JD, Rozier G, Harris R, et al. Dental caries prevention: The physician's role in child oral health systematic evidence review [internet]. Rockville, Md. Agency for Healthcare Research and Quality (US); 2004 Apr.

http://www.mouthhealthy.org/en/nutrition/food-tips/9-Foods-That-Damage-Your-Teeth (accessed on 12/17/2014)

http://www.healthdirect.gov.au/teeth-cleaning (accessed on 12/17/2014)

http://www.urmc.rochester.edu/encyclopedia/content.aspx?ContentTypeID=1&ContentID=4062 (accessed on 12/17/2014)

http://www.nlm.nih.gov/medlineplus/ency/article/001055.htm (accessed on 12/17/2014)

http://womenshealth.gov/publications/our-publications/fact-sheet/oral-health.html?from=AtoZ (accessed on 12/17/2014)

http://www.mayoclinic.org/diseases-conditions/cavities/basics/prevention/con-20030076 (accessed on 12/17/2014)

Helpful Peer-Reviewed Medical Articles:

Selwitz, R. H., Ismail, A. I., & Pitts, N. B. (2007). Dental caries. The Lancet,369(9555), 51-59.

Sheiham, A. (2006). Dental caries affects body weight, growth and quality of life in pre-school children. British dental journal, 201(10), 625-626.

Dugmore, C. R., & Rock, W. P. (2004). A multifactorial analysis of factors associated with dental erosion. British dental journal, 196(5), 283-286.

Islam, B., Khan, S. N., & Khan, A. U. (2007). Dental caries: from infection to prevention. Medical Science Monitor, 13(11), RA196-RA203.

Sheiham, A. (2001). Dietary effects on dental diseases. Public health nutrition, 4(2b), 569-591.

Kantovitz, K. R., Pascon, F. M., Rontani, R. M. P., & Gaviao, M. B. D. (2006). Obesity and dental caries-A systematic review. Oral Health and Preventive Dentistry, 4(2), 137.

Dye, B. A., Shenkin, J. D., Ogden, C. L., Marshall, T. A., Levy, S. M., & Kanellis, M. J. (2004). The relationship between healthful eating practices and dental caries in children aged 2–5 years in the United States, 1988–1994. The Journal of the American Dental Association, 135(1), 55-66.