PROPHYLAXIS means “to prevent”. In dentistry, the term refers to professional cleaning, scaling, and polishing of the teeth by a dental professional. The purpose of prophylaxis is the prevention of gingivitis, chronic periodontitis (gum disease), and tooth decay. Notwithstanding, it should be made clear that occasional professional prophylaxis cannot substitute for adequate daily personal oral hygiene.
Some types of primary prevention require professional intervention. Poliomyelitis, smallpox, and diphtheria can be prevented by vaccines that stimulate the formation of antibodies in the blood to combat the invading organism when we are exposed later on. There are no effective vaccines to fight the many bacteria and viruses that cause common oral diseases. Instead, we rely on preventive measures such as personal oral hygiene and periodic dental prophylaxis.
Additionally, prophylaxis aims to eliminate deposits on the teeth that cannot be removed by diligent brushing and flossing. It consists of scaling the teeth to remove tartar and coronal polishing to remove stains. Stains present no significant problem other than they may detract from your appearance. It is the tartar and plaque on the crowns and roots above and below the gum – supragingival and sub-gingival deposits – that present a health risk unless they are removed. This is because you can lose the tooth if it is not eliminated.
Plaque begins to form almost immediately after prophylaxis, but it takes about three months for toxic products in retained deposits to mature to the point where tissue damage begins to occur. In a healthy mouth, this time is extended by daily brushing and flossing. Nonetheless, plaque creeps down along the sides of the teeth into the gingival sulcus. Since plaque cannot be entirely removed from the sulcus by personal effort, periodic professional treatment, as frequently as every three months for patients with periodontal disease, is necessary to remove the remaining deposits. Thus, removing soft and hard subgingival plaque, not stain removal, is a significant function of prophylaxis. Thorough tooth brushing and flossing daily remove food debris and newly formed plaque and minimises tartar formation. But once plaque and tartar are firmly established beneath the gum tissue, professional scaling, and root planning are necessary to remove it and to maintain periodontal health.
Coronal polishing is usually performed with a rubber cup mounted on the dental handpiece, which most people call “the drill”. A small amount of polishing paste, similar to toothpaste but more abrasive, is placed in the rubber cup, which is then rotated against the exposed surfaces of the teeth to remove the stains. Stains within the recesses of tiny cracks, pits, and fissures have to be scraped off with picks and scalers or blown away with a mildly abrasive air jet. Coronal polishing of all the teeth can be accomplished in a few minutes.
Stains come in various colours, from green to brown to black. Green stains are usually found on the upper front teeth of young children – the incisors. When these teeth first come into the mouth, they are covered by a thin cuticle, a remnant of the surrounding sac in which the teeth develop. This cuticle, which is stained by bacteria and fungi normally present in the mouth, usually wears off in a few years, but sometimes professional coronal polishing is necessary to remove it. I am always reluctant to clean children’s teeth because of the potential damage to the enamel, which can never grow back. Similarly, in adults, the more the teeth are polished, the more yellow they become due to the wearing away of the opalescent white enamel with the dental abrasives used by the dental professional.
Some black and brown stains are the result of pigments produced by bacteria. Most stains in adults come from tobacco, coffee, tea, and coloured food and can usually be removed easily. However, not all stains can be removed by coronal polishing. Tobacco stains can permanently discolour teeth in heavy users. The teeth of miners exposed to copper and iron dust may be permanently discoloured green or brown. Drugs containing similar metal salts have the same effects. But by far, the worst medically induced discolouration results from an improper prescription of tetracycline, an otherwise exceptionally safe antibiotic. Tetracycline staining occurs when the drug is administered during the last half of pregnancy and the first eight years of childhood. During this period, crowns of the permanent teeth are developing, and tetracycline produces a grey, yellow, or brown discolouration that ranges from mild to severe. Because most physicians and dentists are now aware of this danger and substitute other antibiotics, tetracycline staining in children is no longer as common as it used to be. The condition is not damaging to the teeth other than their appearance. In many cases, a dentist can bleach the teeth to a natural light yellow–white hue. If repeated bleaching fails, the teeth can be resurfaced with composite or laboratory-fabricated veneers.
