Combatting periodontal (gum) disease
Gum or periodontal disease -- one of the commonest causes of adult tooth loss -- is an almost entirely preventable condition. Caught early it can be reversed by good oral hygiene and regular dental visits.
Gum disease, or to give the condition its correct name, periodontal disease (from the Greek peri: for around and odont: for tooth) is popularly regarded as an inevitable part of aging, associated with bad breath and lengthy dental treatments. About nine out of 10 Canadians experience occasional gum inflammation (inflamed gingival tissues), but it's now clear that good oral hygiene and professional dental care can prevent periodontal disease or reduce it to a level that need not permanently weaken tooth attachment.
Not an inevitable part of growing older
While periodontal disease is a serious threat to dental health, it need not accompany normal aging. The modern dental approach is to regard periodontal disease as an avoidable infection that can be prevented or kept well under control by sound antibacterial measures including: good home mouth-care and regular, professional cleaning by a dentist or dental hygienist. Thorough tooth brushing and, more importantly, between-the-teeth cleaning, (e.g., by flossing) go a long way in preventing periodontal disease and helping us keep our teeth to a ripe old age. But estimates show that fewer than half of all Canadians regularly visit a dentist and many fail to practise even the minimum amount of daily mouth-care needed to keep gum infection at bay. Many are particularly negligent about daily between-the-teeth cleansing -- although periodontal disease usually starts between the teeth.
Bacteria in plaque largely to blame
When the 17th century Dutch microscopist, Anton Van Leeuwenhoek, examined the whitish matter scraped from the surface of his own teeth under his newly invented microscope, he was amazed to see hundreds of tiny creatures, which he called "small living animalcules that moved very prettily." In today's terms, the substance Van Leeuwenhoek had dislodged from his teeth was dental plaque, and the animalcules he observed were some of the mobile bacteria commonly teeming in it. As we know today, bacteria in plaque are the primary cause of virtually all periodontal diseases. Plaque is the soft, gummy deposit on teeth, dentures and fillings that makes them feel unpleasantly furry in the mornings (when it has had a chance to accumulate overnight). Plaque consists of a complex community of different bacteria, their nutrients and waste products. Scientists estimate that one gram of adult human plaque contains no less than 1,700,000,000,000 (1.7x[10.sup.11]) organisms of a few hundred different species. Plaque starts to form minutes after the teeth are brushed, and within 12 hours of even the most through tooth cleansing, gluey, organized, bacterial colonies begin to coat the teeth. After 24 hours the bacteria in plaque already adhere tenaciously to the tooth surfaces -- which explains why it's wise to brush teeth more than once a day! Plaque tends to accumulate particularly quickly when salivary flow is low and the mouth is dry -- as during sleep, times of stress, and in people on certain medications, e.g., antihistamines, sedatives, antihypertensives or blood pressure pills (such as diuretics), which decrease salivary flow. Medication-induced reduction of saliva and increased risk of periodontal disease can be particularly troublesome in the elderly. The greater the amount of plaque, the greater the chance of irritating the gingival (gum) tissues. Besides its quantity, the types of bacteria in plaque influence the kind and extent of periodontal disease. While some types of bacteria in plaque live in harmless harmony within the mouth, others are pathogenic (health-damaging) strains that injure the teeth and tissues around them. For instance, one harmful bacterial strain in plaque, Streptococcus mutans, is considered responsible for dental caries (tooth decay) while other bacteria -- present in subgingival plaque beneath the gumline -- attack the gingival tissues (gums) themselves rather than the teeth. As plaque accumulates, it gradually acquires more and more destructive bacteria that, together with their toxic metabolic by-products, attack the oral tissues and trigger the body's inflammatory response. Just like an inflammatory response elsewhere in the body, several defence reactions occur. Special protective white blood cells accumulate -- such as bacteria-digesting neutrophils (large white cells important to immune defences) and macrophages (giant, bacteria-fighting cells). A biochemical chain reaction is unleashed which produces the redness, swelling and bleeding typical of early periodontal disease. Certain types of bacteria may cause "bad breath" by producing volatile sulfur compounds such as hydrogen sulfide (which smells like rotting eggs). Calculus or mineralised plaque -- popularly known as tartar -- is another substance that collects on the teeth when calcium and phosphate in saliva crystallize plaque into hard, discoloured deposits clearly visible to the naked eye. Like coral in the ocean, calculus provides a rough surface or calcified niche on which bacteria can proliferate within a "protected" environment. Thus calculus contributes sizeably to bacterial irritation of the gingival tissues. Calculus cannot be removed by mere brushing and flossing but requires professional scaling (cleaning). Since periodontal disease is directly due to plaque accumulation (a mild bout may arise if someone simply stops brushing the teeth), a superficial episode can be reversed by scrupulous plaque removal and anti-bacterial measures -- good home oral hygiene and regular visits for plaque removal from areas a toothbrush can't reach by a dentist or dental hygienist. Each professional dental scaling session is followed by a "post-cleansing" shift in the bacterial composition of plaque, altering the balance in favour of less harmful types for a while, giving the oral tissues a period of grace in which to recover their health. Dental hygienists are an integral part of some dental practices and, in addition to the direct care given by a dentist, they help to educate people about good oral health. Acting as preventive specialists, working under a dentist's supervision, they focus on the prevention of periodontal disease and tooth decay. The dental hygienist examines and assesses the health of all tissues in the mouth and throat, records the findings and discusses them with the supervising dentist, also cleaning the teeth -- scaling them to remove deep-seated plaque and calculus, and polishing them to remove stain. When appropriate, fluoride and sealants are applied to prevent tooth decay. In addition, the hygienist demonstrates the best way to clean teeth in order to minimize plaque build-up. After cleaning by a hygienist, the dentist examines the mouth. While a dentist is responsible for general dental care, when patients have serious periodontal disease, they may be referred to a periodontist for specialized care.
Distinguishing the two main categories of periodontal disease
Periodontal disease, a general term for a number of conditions affecting the tissues around the teeth, lumps together minor and serious conditions. Thus some of the frightening statistics suggesting that "almost everyone will get gum disease," are exaggerated as they include both mild, easily reversible forms (gingivitis) and harder-to-treat, deeper infections of tooth-supporting structures (periodontitis). Gingivitis (from the Latin for gums) is a relatively common, reversible inflammation that affects many adolescents and adults at some time during their lives, generally producing at worst no more than a little bleeding, swelling and redness around the gumline. It is completely curable with good oral hygiene and professional care. Moderate periodontitis, a less common but more persistent bacterial infection, affects about 40 per cent of adults. It may extend deep into the tissues that support the teeth, penetrating not only the gingiva, but also the periodontal ligaments, cementum and the jaw bone itself. Advanced periodontitis, which affects about 10 per cent of the population, can have lasting consequences -- including loosening of the teeth and their eventual loss.
Ordinary gingivitis -- often just an annoyance
Gingivitis often arises during adolescence, when tooth-cleaning is sloppy, but is usually a disease in name only, causing little "dis-ease" -- little pain and discomfort (except for the form once called trench mouth).
Other types of gingivitis
* Acute, necrotizing, ulcerative gingivitis (ANUG) -- also known as trench mouth -- is an extremely unpleasant infection, characterized by painful gingival ulcers, acute inflammation and fetid, bad breath. Severe cases may involve swollen lymph glands, fever and malaise. Factors that aggravate trench mouth include: stress, anxiety, fatigue, immune system defects, severe nutritional deficiencies, smoking and gross neglect of oral hygiene. Although becoming rare, ANUG has recently surfaced again as an early infection in people with AIDS or those who carry HIV (human immunodeficiency/AIDS viruses). * Steroid or hormone-induced gingivitis. The rise in estrogens and progestogens during adolescence and pregnancy or in women using oral contraceptives may exacerbate pre-existing gingivitis. * Medication-induced gingivitis. Some drugs, such as phenytoin (Dilantin), used for epilepsy, or cyclosporin, used for immunosuppression in organ transplants, may cause unusually severe gingival enlargement and inflammation. * Malnutrition can aggravate periodontal disease, especially severe protein deficiency and a lack of folic acid (Vitamin B), Vitamin C or zinc -- rare in North America today. * Other factors that may exacerbate gingivitis include: diabetes, mal-aligned teeth (a bad bite/occlusion) and faulty restorative dental work (e.g., poorly contoured fillings, bridges and crowns) which hamper good mouth cleaning, making it hard to keep plaque down. Faulty fillings near the gumline are known to cause a local shift in periodontal bacteria, favouring disease-inducing strains.
Gingivitis may progress to the more serious periodontitis
During the 1950s, dental scientists believed that gingivitis and periodontitis formed one continuum -- that untreated gingivitis inevitably led to periodontitis, which in turn, if left unchecked, inexorably led to tooth loss. This belief has changed. Although in some people gingivitis progresses to periodontitis, it does not always do so and some cases of periodontitis don't advance at all or deteriorate very slowly. The reasons for the transition from a mild gingival inflammation to a deep infection, or periodontitis, are obscure. It may depend on a complex interaction between specific bacteria, individual resistance, the immune response and barriers to infection. The progress of periodontal disease -- from a mild inflammatory condition to a deep infection -- is insidious, silent and hard to detect even by an observant person, often giving few signs of its advance until some bone loss has occured. Periodontitis can advance unnoticed, giving no pain or discomfort until considerable tooth loosening has occurred. It is usually detectable only by careful, expert periodontal examination with the right instruments. At present it's not possible to predict in whom the mere redness and tissue puffiness of gingivitis is likely to progress to the more serious periodontitis. Since there's no easy way to identify those at greatest risk, everyone is encouraged to eliminate gingivitis, get rid of the bacteria and reduce plaque formation.
Periodontitis -- a much nastier disease
Periodontitis is a slowly progressing infection that flares in cycles of destructive bacterial activity, advancing little by little, down the root of the tooth. As with gingivitis, the bacteria in plaque initiate periodontitis when the oral environment becomes receptive to pathogenic bacteria, allowing them to flourish -- favouring the emergence of certain anaerobic (non-oxygen using) forms that penetrate deep under the gingival tissues (sometimes down to the bone). The tissue destruction weakens tooth attachment so that the teeth become jiggly or loose. (Fortunately, fewer people actually lose their teeth due to severe periodontitis than was once believed.) As the infection progresses, the swollen tissues recede and detach from the tooth surfaces, forming deep pockets or spaces between the gingiva and the teeth. The fast-moving, anaerobic bacteria responsible for periodontitis thrive in the oxygen-less environment and cannot be removed by normal home cleaning procedures. While plaque removal may help to control moderate periodontitis, it is not enough for severe cases. As the infection deepens and periodontal pockets form, the destructive process becomes irreversible, so that lost or damaged tissues can't be regenerated simply by removing the bacterial agents. Periodontitis is generally associated with specific types/species of highly pathogenic (destructive) bacteria (e.g., Bacteroides, Treponema, Wolinella, Actinobacillus, Fusobacterium, Eikenella, Capnocytophaga and Peptostreptococcus). Just as physicians refer to the bacteria that cause different types of pneumonia (e.g., pneumococcal or viral pneumonia), dental experts may speak of Bacteroides or Actinobacillus -- associated periodontitis, according to the microorganisms responsible.
Diagnosing and treating periodontal disease
To assess the amount of periodontal damage or bone loss, dentists use X-rays, and an instrument called a periodontal probe, marked off in millimetres, inserted into the periodontal pocket to judge its depth and determine the extent of bone resorption (disappearance). In the earlier stages of disease (pockets four to six millimetres or less in depth), professional scaling and planing to remove most of the harmful plaque and calculus, together with meticulous home mouth care may be all that's needed. Unfortunately, about 15 per cent of cases resist all known treatments, and for such unresponsive cases finding the "right antibiotic" would be an invaluable adjunct to therapy. One modern treatment approach tries to identify the specific bacteria responsible and reduce or eradicate them with appropriate antibiotics. Special commercial laboratories that use DNA probes can now assist dentists in determining the specific bacteria contributing to periodontal damage so that patients may be treated more accurately with selected antibiotics. The University of Toronto Department of Periodontics runs a consulting service for patients plagued by recurrent periodontal deterioration. People may be referred to this service only by their own specialists for microbial analysis to help decide which antibiotics might be most helpful. Currently under review are better ways to deliver mini-doses of antibiotics (locally-acting forms) directly to the sites of infection. Already, tetracycline, metronidazole or the antiseptic chlorhexidine, administered by slow-release resin strips tied around teeth, can deliver high doses right to the sites of infection without over-medicating the whole body.
Some forms attack young people
Localized juvenile periodontitis is a particular form of periodontal disease that strikes mainly teenagers and young adults, affecting primarily the front teeth and first molars. An uncommon condition (about one to three per 2,000 people), it tends to run in families -- perhaps affecting 50 per cent of family members. Two particular features of juvenile periodontitis may help to shed light on adult periodontitis. Firstly, a specific bacterium (Actinobacillus actinomycetem-comitans) has been linked to the disease. Secondly, some patients have a specific defence system flaw -- their protective neutrophils (white blood cells) do not migrate normally to the site of infection and fail to ingest and kill the bacteria. This combination of host dysfunction with attack by a specific bacterium leads to rapid early tooth loss -- even during the teen years. Fortunately, the condition responds well to correct antibiotic treatment. Success in identifying the microbial cause of juvenile periodontitis and treating it with accurately targetted antibiotics has spurred research into antibiotic treatments for recurrent adult periodontitis.
Periodontal surgery may be needed for extensive disease
Periodontal surgery exposes the affected area so that the debris that causes infection can be more effectively removed. The gingiva/gum tissue is then re-attached in a way that reduces the periodontal pockets (spaces) and impedes bacterial colonization. Periodontal surgery is generally considered a last resort for treating advanced disease. Flap surgery, the most common form of periodontal surgery, is undertaken when the bone is involved, to lift away a gingival "flap," exposing the tooth root for rigorous cleaning and the bone for minor contouring or placement of various grafting materials. Then the gingiva is sutured back in place. New forms of surgery, including a method called "guided tissue regeneration," currently receiving much coverage, may promise better results for the future. Whereas in the past dentists could stop the bacterial activity, they could not restore tissue that was already lost. The new surgical approach tries to encourage growth of cells from the periodontal ligament over the exposed root surface to stimulate a healing process which may "regenerate" lost supporting tissue. The increased risk of root surface decay following surgery makes it absolutely essential that surgical patients stop snacking on sweets, maintain meticulous hygiene and return for frequent professional care, including application of fluoride to root surfaces.
Researchers pioneer new approaches
Among the hottest areas of periodontal research is a search for better biological methods to measure disease activity in order to pinpoint those most likely to develop active periodontal disease. To this end, many new diagnostic aids are being developed, including high-tech measuring devices to record disease progress more accurately. University of Toronto dental researchers have helped to develop such methods. An automated aluminium, computer-assisted periodontal probe can now measure even minor losses of tooth attachment and chart their progress by a highly accurate technique. This method may pave the way for devices by which dentists can automatically track the course of periodontal disease by computer. A recent chemical test measures small amounts of the destructive enzyme, collagenase, produced by a patient's own white blood cells in response to inflammation -- to identify periods of disease activity. Testing gingival fluid (or even an oral water swish) for its collagenase content would give a more direct, less laborious diagnostic test to identify periods of bacterial activity and to monitor the success of treatment.
The bottom line
Since periodontal diseases are directly linked to plaque formation, the best way to prevent them is by meticulous plaque removal using good oral hygiene, -- supplemented by regular dental visits for professional cleaning and check-ups to detect early signs of periodontal disease. Regular visits to the dentist should start when a child's primary teeth are in, between the age of two and three. For the treatment of entrenched periodontitis, professional care, sometimes including the use of antibiotics and, perhaps also in future, anti-inflammatories, offers a most promising outlook.
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