Oral health is an integral part of general health and well-being. Good oral health enables individuals to communicate effectively, to eat and enjoy a variety of foods, and is important in an overall quality of life, self-esteem and social confidence. Oral diseases are highly prevalent and their impact on both society and the individual is significant. Pain, discomfort, sleepless nights, limitation in eating leading to poor nutrition, and time off school or work because of dental problems are all common effects of oral diseases.Oral diseases are however largely preventable. Although advances in clinical operative techniques have made dental treatment more effective and acceptable, treatment approaches alone will never eradicate oral diseases. Effective dental public health approaches are therefore required to prevent oral diseases and promote oral health across the population.What do we mean by dental health? Dental health refers to all aspects of the health and functioning of our mouth especially the teeth and gums. Apart from working properly to enable us to eat, speak and laugh, teeth and gums should be free from infection, which cause dental caries, inflammation of gums, tooth loss and bad breath. Dental cavities are the most common disorder affecting the teeth. The main factors controlling the risk of dental cavities is oral hygiene, exposure to fluoride and a moderate frequency of consumption of decay-causing foods  such as cakes, biscuits, chocolates, sweets and other confectionaries.Periodontal disease, also known as gum disease, is caused by infection and inflammation of the gum, the periodontal connective tissues and the alveolar bone and can cause tooth loss.Why is dental health important? The health of our teeth and mouth are linked to overall health and well-being in a number of ways. The ability to chew and swallow our food is essential for obtaining the nutrients we need. Apart from the impact on nutritional status, poor dental health can also adversely affect speech and self-esteem. Dental diseases impose both financial and social burdens as treatment is costly and both children and adults may miss time from school or work because of dental pain.Why and how are dental cavities formed? Dental cavities, the most common disorder affecting the teeth, are an infectious transmissible disease where acids produced by bacteria dissolve the teeth. Certain bacteria such as Streptococci mutans and Lactobacilli are decay causing. They cause a sticky film, known as dental plaque, on the surface of the tooth. Bacteria in dental plaque use fermentable carbohydrates to form acids. Fermentable carbohydrates are sugars and other carbohydrates from food and drink that can be fermented by bacteria. The acids formed dissolve minerals such as calcium and phosphate from the tooth. This is called demineralisation.However, tooth decay is not inevitable. Saliva clears food debris from the mouth, neutralises acids produced from plaque bacteria and provides calcium and phosphate to the teeth in a process called remineralisation. Saliva also acts as a reservoir for fluorides from toothpaste. Fluoride helps control dental caries by re-mineralising the teeth and inhibiting bacterial acid production, which reduces or slows the decay process. Susceptibility to dental cavities varies between individuals and between different teeth within one person’s mouth. The shape of the jaw and oral cavity, tooth structure and the quantity and quality of saliva are all, important factors when determining why some teeth are simply more susceptible to decay than others. For example, some teeth may have pits, small cracks or fissures that allow bacteria and acids to infiltrate more easily. In some cases, the structure of the jaw/dentition renders teeth more difficult to clean or floss. The quantity and quality of saliva determines the extent to which teeth re-mineralise. For example, relatively fewer caries are generally found in the lower front part of the mouth where teeth are more exposed to saliva.The type and number of caries-causing bacteria present in the mouth is also relevant. All bacteria can turn carbohydrates into acids but certain families of bacteria such as Streptococci and Lactobacilli are more powerful acid producers. The presence of this type of bacteria in plaque increases the risk of decay. Some people have higher levels of decay-causing bacteria than others do, due to neglected or inappropriate oral hygiene. A smile is the shortest distance between two people and reflects the best about the person practicing it.Teeth are important, for not only the smile and speech, but for their contribution to the structure of the face and the jaw.An increase in oral hygiene including regular brushing and flossing to remove plaque and the use of fluoridated toothpaste, combined with regular dental check-ups, is responsible for the improvement of oral health. Fluoride inhibits demineralisation, encourages remineralisation and increases the hardness of the tooth enamel making it less acid soluble. The proper amount of fluoride helps prevent and control caries. Fluoride can be supplied systemically through fluoridated community drinking water, other fluoridated beverages or by supplementation. Alternatively, it can be provided topically direct to the tooth surface via toothpaste, mouth rinses, gels and varnishes. Brushing and flossing helps concomitantly to the fluoride application to remove bacteria from the mouth and reduce the risk of both caries and periodontal disease. Regular dental check-ups can help detect and monitor potential problems. Regular plaque control and removal can help diminish the incidence of dental caries. If very little plaque is present, the amount of acid formed is insignificant and decay cannot occur.Some foods help protect against tooth decay. For example, hard cheese increases the flow of saliva. Cheese also contains calcium, phosphate and casein, a milk protein, which protects against demineralisation. Finishing a meal with a piece of cheese helps counteract acids produced from carbohydrate foods eaten at the same meal. Milk also contains calcium, phosphate and casein, and the milk sugar, lactose, is less cavity causing) than other sugars. Consumption of fresh fruits and vegetables are also important for oral health as they play a big role in the prevention of oral cancer.Good oral hygiene and the use of fluoride are now considered the main factors responsible for preventing tooth decay and promoting good oral health. The following advice is also important for keeping teeth caries-free. Start dental care early, brush baby’s teeth with a fluoride toothpaste as soon as they appear in the mouth. Do not habitually allow infants to fall asleep while drinking from a bottle of milk,  formula, juice or sweetened drink. These sweet liquids pool around the baby’s teeth for long periods of time and can lead to "baby bottle tooth decay”.  Brush teeth twice a day with fluoride toothpaste. If possible, clean between the teeth with dental floss or toothpicks once a day. Do not eat after cleaning teeth at bedtime as salivary flow decreases as we sleep.  Visit the dentist about every 6 months for a check-up. And seek dentist’s advice before using aesthetic products (e.g teeth whiteners) that could have a deterious effect on the teeth. Do not nibble food or sip drinks continuously. Allow time between eating occasions for saliva to neutralise acids and repair the teeth. People at high risk from tooth wear and erosion   should take special precautions, such as decreasing the frequency and contact with acidic foods and drinks and avoiding brushing teeth immediately after consuming acidic foods, drinks, citrus fruits and juices. This allows time for remineralisation to occur. Fluoride mouthwashes and sugar-free chewing gum may be useful after taking acidic food or drinks as they encourage remineralisation.Sugar-free chewing gum is "tooth friendly” as it helps increase saliva flow and clears food debris from the mouth. Good dental health is the responsibility of individuals, communities and governments although their relative importance varies. Therefore, responsibility for preventing tooth decay lies largely with the individual. Dental professionals play an essential role in monitoring dental health and treating or preventing any problems. Access to good dental care, including regular check-ups is vital. For some people, especially those from lower socio-economic groups, access to dental professionals may be limited. These groups are important targets for dental health education programmes. Schools also play an important role in educating children on the importance of good oral hygiene and diet. Improving and maintaining dental health through prevention and promotion is more effective way to achieve good health in the long term.Clinical prevention and health education approaches are very costly and are dependent upon the availability of appropriately trained dental health personnel. To achieve effective oral health gains, dental health strategies based upon the common risk factor approach are significant and have to be adhered to. If the above advice on how  to ensure dental health is followed, Rwandan population will have  free-caries mouths and other oral diseases such as oral cancer.Lt Col Frank Rwema (MDPH), is an Oral Health Specialist working in the Preventive Dentistry Department at Rwanda Military Hospital.