4 questions | Applied Sciences homework help

1. Rubsamen D. Psychiatrist’s seduction of patient results in $1.5 million jury verdict. Psychiatric News, p 15, Mar 15, 1990.

Dental Care The majority of dentists work in the privacy of their own office, where they usually are not subject to review by knowledgeable colleagues. This situation, plus the fact that the harm done by poor dental care may not become apparent for many years, makes it difficult for consumers to evaluate the quality of the treatment they receive. John E. DoDEs, D.D.s.1 Chapter Seven © 1980 stephen barrett, m.d. Part Two Health-Care Approaches112 Dental diseases are among the most prevalent ail- ments in the United States. The total cost of dental services in 2009 was about $110 billion. Tooth decay (caries) affects nearly everyone. Periodon- tal (gum) disease results in greater tooth loss than any other cause. Although proper care enables most teeth to last a lifetime, about 25% of Americans older than 65 are toothless. Misconceptions about dental disease are common. Misinformation is spread by advertisers, food faddists, the media, and misguided or poorly informed health professionals. This chapter covers the causes, prevention, and treatment (both appropriate and inappropriate) of dental problems. Tobacco products, which can adversely affect tissues in the mouth, are discussed in Chapter 14. Dental insurance is covered in Chapter 23. Dentists Dentists are licensed practitioners who hold either a doc- tor of dental surgery (D.D.S.) degree or the equivalent doctor of dental medicine (D.M.D.) degree. Becoming a dentist requires a minimum of 2 years of predental college work followed by 4 years of dental school. However, almost all students entering dental school have a baccalaureate degree. There are 57 accredited dental schools in the United States. The first 2 years of dental school consist largely of basic and preclinical sciences. The last 2 years are spent primarily in dental practice under faculty supervision. State licensure is then acquired by passing a combination of national and either state or regional examinations. Dentists who wish to specialize spend 2 or more years in advanced training. To become board-certified they must then pass an ex- amination administered by a specialty board recognized by the American Dental Association (ADA). The nine recognized specialties are: DEntal public hEalth: Promotion of community dental health EnDoDontics: Prevention and treatment of diseases of the root pulp and related structures (root canal therapy) oral anD maxillofacial pathology: Diagnosis of tumors, other diseases, and injuries of the head and neck oral anD maxillofacial raDiology: Radiologic diagnosis and treatment of head and neck disorders oral anD maxillofacial surgEry: Tooth extractions; surgical treatment of diseases, injuries, and defects of the mouth, jaw, and face orthoDontics anD DEntofacial orthopEDics: Diagnosis and correction of tooth irregularities and facial deformities pEDiatric DEntistry: Dental care of infants and children pErioDontics: Treatment of diseases of the gums and related structures prosthoDontics: Treatment of oral dysfunction through the use of prosthetic devices such as crowns, bridges, and dentures Some dentists claim to specialize in “cosmetic den- tistry,” but this is not a recognized specialty. The ADA estimates that during 2006, 180,000 den- tists were professionally active in the United States, with about 165,000 in private practice. About 75% of dentists are ADA members. allieD Dental Personnel The services of dentists are complemented by dental assistants, registered dental hygienists, and dental labo- ratory technicians. Dental assistants have been part of the dental health- care team since 1885. The duties they may legally per- form vary from state to state and can depend on the extent of their training. They may include preparing patients and materials, sterilizing instruments, keeping records, and taking x-ray films. Many assistants are trained by the dentists who employ them. Others have taken a short

• Good teeth contribute not only to appearance but to the quality of life as well.
• The key to dental health is prevention, the cornerstones of which are good oral hygiene and fluoride.
• Community water fluoridation is the most effective and cost-effective way to obtain adequate fluoride intake.
• With proper care, teeth should last a lifetime. Self-care should involve daily brushing and flossing. The frequency of dental visits should be based on an assessment of cavity formation, the rate of calculus deposition, the condition of the gums, an individual’s specific needs, and any related medical issues.
• Dentists who routinely recommend removal of amalgam fillings or teeth that have undergone root canal therapy are not trustworthy and should be avoided.

KeeP these Points in MinD as You stuDY this ChaPter Key Concepts Chapter Seven Dental Care 113 commercial course or received special training for ex- panded functions. The Certified Dental Assistant (CDA) credential, administered by the Dental Assisting National Board, is recognized or required in more than 37 states. Candidates may qualify for the certification examina- tion by graduating from an accredited dental assisting education program or by having 2 years of full-time or 4 years of part-time experience as a dental assistant. The requirements for taking x-rays films or doing other advanced procedures vary from state to state.2 Registered dental hygienists (RDHs) provide clini- cal and educational services in private dental offices, schools, industrial plants, and public health and other government agencies. Their activities include perform- ing oral prophylaxis (cleaning and polishing teeth), taking and processing x-ray films, conducting caries screening, and teaching oral health care. The training of dental hygienists takes 2 years for an Associate of Arts (AA) or Associate of Science (AS) degree. There are also bachelor (BS-DH).and Master of Science (MS-DH) programs. After completing the National Board of Dental Hygiene Examination, they must pass a state or regional examination for licensure, which also entitles them to use the RDH credential. The scope of dental hygiene practice varies from state to state and has gradually expanded. Dental laboratory technicians are trained to con- struct and repair oral appliances such as crowns, bridges, and dentures. Training in dental laboratory technology is available through universities, community and junior colleges, vocational-technical institutes, and the Armed Forces. In 2008, 20 programs were accredited by the Commission on Dental Accreditation in conjunction with the ADA. Most such programs take 2 years to complete; a few can take up to 4 years.3 Certification is available from the National Board for Certification in Dental Laboratory Technology. Certified Dental Tech- nicians (CDTs) specialize in one or more of five areas: complete dentures, removable partial dentures, crowns and bridges, ceramics, and orthodontics. Dental laboratory technicians usually work under a dentist’s direction, either in the dentist’s office or in a commercial laboratory. Those who work independently, selling directly to the public, are referred to as denturists. Denturism is illegal in most states. tooth DeCaY Figures 7-1 and 7-2 show the names and locations of the teeth and their component parts. Tooth decay (dental caries) is caused by bacteria in the mouth that produce acids harmful to tooth enamel. It is a highly complex phenomenon that involves the interaction of hereditary factors, specific cariogenic bacteria, nutritional factors, dietary habits, oral hygiene, and time. Some medications and abused drugs can also cause caries. Various studies suggest that caries can be reduced by decreasing the number of decay-producing bacteria in the mouth. New caries is especially common during adolescence. Although sugar consumption has an effect on dental caries, the amount of sugar in the diet is not as important as the frequency of eating, the acid-buffering capacity of the saliva, whether the sugar is in a food that sticks to the teeth, the availability of fluoride, and the individual’s oral-hygiene practices. Food faddists teach that honey, raw sugar, and other “natural” sweets are nutritionally superior, and that Figure 7-2. Schematic cross-section of an incisor tooth in its bony socket. Enamel Dentin Gum Root canal containing nerves and blood vessels Bone (jaw) Crown Root (portion below the gum) Pulp (nerves and blood) Figure 7-1. Schematic drawing of adult teeth. The upper teeth are numbered as shown. The lower teeth are numbered from #17 (under #16) to #32 (under #1). Modified from Thibodeau GA, Patton KT. Anatomy and Physiology, ed 3. St. Louis, 1996, Mosby. Front view of upper teeth, mouth open Second premolar Upper incisor Canine First premolar Central incisor First molar Second molar Third molar (wisdom tooth) 1 16 11 10987 6 5 12 13

LEFTRIGHT

Part Two Health-Care Approaches114 white sugar is bad because it is “empty calories.” They also suggest that natural sugars are less apt to produce tooth decay. Both of these ideas are false. The vitamin content of natural sugars is minuscule. Honey is at least as cariogenic as refined sugar (sucrose) in the same con- centration. The faddists’ suggestion to substitute granola for conventional presweetened cereals is also foolish. (Granolas are made with oats, honey, dried fruit, and brown sugar.) Decay-causing germs make no distinction between sugars from different sources. They digest them all and produce acids that attack (demineralize) tooth structures. The more often a person eats between meals and the longer fermentable carbohydrates remain in contact with the teeth (as sticky sweets are most prone to do), the more the teeth are subjected to demineralization. Remineralization (healing) occurs between periods of acid exposure and is aided by fluoride ions and other substances in saliva. Whether decay occurs depends on whether demineralization exceeds remineralization. Tooth damage has been reported in users of vitamin C (ascorbic acid) tablets who chew rather than swallow them. Ascorbic acid is strong enough to erode tooth enamel over a period of time.4 Acid erosion can also be caused by frequent vomiting (pregnancy or bulimia) or high-acid foods (e.g., sucking on lemons). “Baby bottle tooth decay” is a condition of early childhood in which cavities develop in teeth that have prolonged contact with sugar-containing fluids. To pre- vent it, infants and toddlers should not be permitted to (a) sleep or walk around with a bottle filled with milk, formula, juice, or sweetened drink in their mouth, (b) sleep at night at the breast, or (c) use a pacifier that has been dipped in honey, syrup, or other sweet fluid. Dental Sealants Sealants are thin plastic coatings that can protect the chewing surfaces but not the sides of the back teeth (molars) from decay. Sealants fill the pits and fissures of the chewing surfaces and harden soon after application. They usually last for years and can be reapplied if neces- sary. They are most effective between the ages of 5 and 14 when applied soon after the permanent teeth erupt. The American Academy of Pediatric Dentistry5 advises: The natural flow of saliva usually keeps the smooth surfaces of teeth clean but does not wash out the grooves and fissures. So the teeth most at risk of decay—and therefore, most in need of sealants—are the six-year and twelve-year molars. Many times the permanent premolars and primary molars will also benefit from sealant coverage. Any tooth, however, with grooves or pits may benefit from the protection of sealants. FluoriDation Fluoride, an ion found naturally in most water supplies. can prevent the formation, slow the progression, and even reverse newly forming cavities. When sufficient quantities of fluoride are available, especially during the process of tooth development, the resultant teeth are stronger and more resistant to decay.6 In the early 1900s a Colorado dentist named Fred- erick McKay suspected that something in water caused brown stains on the teeth of members of his community. The mottled teeth also were remarkably free of decay. By 1931 a new technique for water analysis enabled Dr. McKay to identify high fluoride as the cause. Subsequent testing determined that the ideal concentration for pre- vention of caries without mottling is approximately one part of fluoride per million parts of water.7 The first community fluoridation program began in 1945. Today more than 160 million people in the United States are served by community fluoridation and about 10 million more have protective levels of naturally occurring fluoride in their water. Recognition of fluo- ride’s importance to dental health has led to dramatic declines in the prevalence and severity of tooth decay. Government surveys have found that the percentage of children with caries-free permanent teeth rose from 28% in 1971–1974 to 36.6% in 1979–1980 and 49.9% in 1986–1987.8,9 In 1999, the U.S. Centers for Disease Control and Prevention listed water fluoridation as among the 10 greatest health achievements of the 20th century.10,11 Fluorides also work when applied to the surfaces of the teeth. This occurs through fluoride in saliva (due to ingested fluoride) and through the use of fluoride toothpaste, mouth rinse, gel, and/or varnish. Unfounded Criticism Strident claims have been made that fluoridation causes cancer, birth defects, Down syndrome, allergies, and a wide variety of other maladies. But none of these claims has held up to scrutiny by qualified scientists.12–17 Former National Council Against Health Fraud president Wil- liam T. Jarvis, Ph.D., has noted: These charges seem to grow out of a mentality of distrust. Antifluoridation groups are led by many of the same people who oppose immunization, pasteurization, sex education, mental health programs, and other public health advances. Most are closely connected with sellers of alternatives to medically accepted products and services. The so-called “health food” industry justifies its existence by declaring that our conventional sources of food, water, and health care are not trustworthy. Chapter Seven Dental Care 115 Too much fluoride can cause fluorosis, which, in its mildest form, causes small, white, virtually invisible opaque areas on teeth. Severe fluorosis causes brownish mottling, which occurs mainly in areas where the natural level of fluoride in water is considerably greater than one part per million. (Severe fluorosis also occurs in certain diseases, but this is not relevant to fluoridation.) For many years, a pamphlet called “Lifesavers Guide to Fluoridation,” was distributed in communities considering fluoridation. The pamphlet cited more than 200 references to back up its claims that fluoridation was ineffective and unsafe. However, experts who examined the references found that nearly half had no relevance to community water fluoridation and that many others actu- ally supported fluoridation but were misrepresented.14

A more recent review concluded:

Opponents of water fluoridation frequently repeat that water fluoridation is associated with adverse health effects. . . . Tech- niques such as “the big lie” and innuendo are used to associate water fluoridation with health and environmental disasters, without factual support. Half-truths are presented, fallacious statements reiterated, and attempts are made to bamboozle the public with a large list of claims and quotes often with little scientific basis. Ultimately, attempts are made to discredit and slander scientists and various health organizations that support water fluoridation.15 Fluoride Supplementtion Fluoridation reduces the incidence of cavities 20% to 40% in children and 15% to 35% in adults.16 The reduction is less than it was during fluoridation’s early days, probably because of improved dental hygiene and widespread use of fluoride toothpaste. Children in areas with negligible amounts of fluoride in the drinking water should be given fluoride drops or tablets prescribed by a physician or dentist. Table 7-1 gives the recommended dosage. Children who drink adequately fluoridated water should not be given supplements. When supplements are given conscientiously from infancy through early adolescence, the level of caries protection approaches that of water fluoridation. How- ever, because few parents have sufficient motivation to carry out such a program, water fluoridation is vastly superior as a public health measure. Topical methods apply fluoride directly to the surfaces of the teeth. They have merit but are not as ef- fective as ingested fluorides that are incorporated into the tooth structure as it forms. Fluoride toothpastes and mouth rinses are available for individual use; gels, pastes, varnishes, and solutions are available for administration by dentists. Topical fluoride methods can be used in nonfluoridated communities and also offer additional caries protection in fluoridated communities. The most rigorous study of preventive dental inter- ventions, the National Preventive Dentistry Demonstra- tion Program, monitored nearly 30,000 children, ages 5 to 14, for four years. It concluded that the most effective and cost-effective way to prevent tooth decay is to drink fluoridated water from birth and have sealants applied as recommended.16 The average annual per-person cost for community fluoridation now ranges from about 50¢ in large com- munities to $3 in small ones. For most cities, every dollar invested saves about $38 in dental treatment costs.17 PerioDontal Disease “Periodontal disease” is the general term for inflamma- tory and degenerative diseases of the gums and other structures that surround the base of the teeth. A common cause of tooth loss between the ages of 30 and 70, it is usually triggered by accumulation of plaque (a soft, sticky, almost invisible film) under the gum. There are several types of periodontal disease, all resulting from bacterial infection that attacks the gums, bone, and ligaments that hold the teeth in the jaw. Concentration of fluoride in water (parts per million) Age (years) 0.0 to 0.3 0.3 to 0.6 Over 0.6 Birth to 6 months None None None 6 months to 3 years 0.25 mg/day None None 3 to 6 years 0.50 mg/day 0.25 mg/day None 6 to 16 years 1.00 mg/day 0.50 mg/day None suPPleMental FluoriDe Dosage (MilligraMs oF FluoriDe Per DaY)* Table 7-1 *2.2 mg of sodium fluoride contains 1 mg of fluoride. Includes nursing infants who usually consume little exogenous water. Commercial formulas contain no fluoride. Recommended since 1994 by the American Dental Association and the American Academy of Pediatrics.18 Part Two Health-Care Approaches116 Without adequate bone and connecting fibers, the teeth loosen and are lost. The earliest stage of periodontal disease is gingivitis, which develops when the bacteria in plaque release toxins that irritate the gums, making them red, tender, swollen, and likely to bleed. The next stage, periodontitis, occurs when toxins destroy the tissues anchoring the teeth to the bone. Gums become detached from the teeth, forming pockets that fill with more plaque. In advanced cases the gums are red and swollen and ooze pus (pyorrhea), painful abscesses may occur, and the teeth lose attachment as the supporting bone is destroyed. Without treatment, teeth can fall out or require removal by a dentist. Diabetics, who are prone to develop infections, are also at higher risk for developing periodontal disease.19 Brushing, flossing, and periodic dental care are the first lines of defense against periodontal disease—as they are against caries. Tobacco avoidance is another important strategy because tobacco use greatly increases the risk of developing gum disease. Adequate daily oral hygiene can prevent or minimize periodontal disease. Gingivitis is evidenced by redness or bleeding of the gums without discomfort. Pink color- ing on the toothbrush bristles may be the first clue that gingivitis is present. Many adults have gingival and early periodontal disease. Because the tissue damage in the later stages of periodontal is not reversible, it is imperative that early signs be recognized and treated even if they cause no discomfort. Surface plaque can be identified with a disclosing solution or tablet. These agents dye the plaque a bright color (usually red) and highlight areas that are missed during cleaning of the teeth. If plaque is allowed to re- main on the teeth, it can harden to form calculus (also called tartar or scale). Calculus is a gum irritant and can host bacteria that cause periodontal disease. Brush- ing with a dentifrice can reduce the amount of calculus above the gumline but not below it. Once calculus has built up, professional scaling is necessary to remove it. Tooth cleaning by a dentist or dental hygienist is advisable at least once a year to remove calculus, which reduces the risk of periodontal disease. Yet many people won’t go to a dentist unless they have troublesome symptoms. Properly performed professional cleaning is a meticulous procedure in which all the calculus, above and below the gumline, is carefully removed with metal instruments called scalers. An ultrasonic device can be used to remove calculus, but its use should be followed with hand-scaling to ensure that the teeth are clean and smooth. The teeth are polished after the scaling. In the late 1970s an oral hygiene program called the Keyes technique was widely promoted as a nonsurgical alternative for treating advanced periodontal disease. The technique includes microscopic examination of the plaque and cleaning the teeth and gums with a mixture of salt, baking soda, and peroxide. Several studies have shown that surgical treatment is more effective. One study found that although the baking soda mixture helped maintain oral health, it was no more effective than ordi- nary toothpaste. The researchers also found that people using the baking soda regimen were three times as likely to stop their program because it was inconvenient. The American Academy of Periodontology has concluded that the Keyes technique did not appear to provide added value over conventional periodontal therapy and was inferior in some instances.20 selF-Care Although individuals can greatly influence their oral health, many people do not take dental problems seri- ously until it is too late. Losing teeth may not be as serious as losing an eye, a hand, or a foot, but people who lose their teeth are handicapped. Dentures are not as comfortable or functional as normal, healthy teeth and can cause difficulty in eating, as well as adverse psychologic effects. Brushing and Flossing Teeth should be cleaned to remove plaque—the soft, sticky, colorless film of bacteria that is constantly forming on their surface. Acids and toxins produced by these bacteria are a major factor in both tooth decay and periodontal disease. The quantity and destructive character of plaque change with the passage of time. It takes about 24 hours for plaque to become sufficiently concentrated to begin causing damage. Pits, fissures, and areas between the teeth where toothbrushes cannot reach provide hideouts for plaque and thus are the sites of most dental problems. One thorough daily cleaning, involving both brush- ing and flossing, is usually sufficient to break up the colonies of bacteria that are continuously being built. A fluoridated dentifrice should be used. The ADA21 advises brushing twice daily. Brushing after meals is primarily for the purpose of dislodging food particles and should be accompanied by rinsing of the mouth. Myth of “Detergent Foods” The idea that eating crunchy foods such as apples and carrots helps to clean the teeth by removing plaque is a myth. At best, chewing can affect plaque on the upper third of the teeth. Areas under the gums where periodon- tal disease occurs are completely unaffected. Chapter Seven Dental Care 117 Dental ProDuCts The ADA performs independent reviews of commonly used commercial dental products. Those judged to be safe and effective are permitted to carry a statement of ADA acceptance on their packages and in their advertis- ing (Figure 7-3). Toothpastes and Gels (Dentifrices) Dentifrices commonly contain abrasives, binding agents, sudsers, coloring agents, moisturizers, sweeteners, preservatives, and water. Many contain a fluoride com- pound. A dentifrice should be abrasive enough to prevent plaque and stain accumulation but not so harsh that it injures teeth or gums.22 The more abrasive toothpastes have little effect on the hard enamel in teeth but can damage the cementum (the soft layer of the tooth just under the gum). As a person gets older, the gums may recede and expose the cementum to possible damage by abrasion. Some products can also irritate the gums themselves. Fluoride dentifrices inhibit dental caries even in adults. They are not a substitute for the fluoridation of community drinking water but are a useful adjunct. Many have been accepted by the ADA Council on Dental Therapeutics as “an effective decay preventive dentifrice that can be of significant value when used in a conscientiously applied program of oral hygiene and regular professional care.” Dentists can recommend fluoride-containing products that are within the proper range of abrasiveness based on their patients’ individual needs. Some dentifrice advertisements make claims about whitening and brightening of teeth. The basic color of the teeth is determined early in life and cannot be made whiter. Abrasive toothpastes may remove minor tooth discoloration caused by substances taken into the mouth, but these toothpastes can easily damage the softer parts of the teeth. Toothpastes and whitening strips containing urea peroxide or hydrogen peroxide can exert bleaching action. However, the wisest course of action for consum- ers who are concerned about tooth discoloration is to discuss the matter with their dentist. If gums recede so that cementum is exposed, the teeth can become sensitive. Use of a dentifrice that contains potassium nitrate (e.g., Sensodyne) lessens this sensitivity in some people.23 Oher treatments to desen- sitize teeth are available from dental practitioners. Fluoride Mouth Rinses The ADA Council on Dental Therapeutics has ac- cepted several nonprescription fluoride mouth rinses as “effective decay-preventive rinses that can be of significant value when used regularly in conjunction with a decay-preventive fluoride dentifrice in a consci- entiously applied program of oral hygiene and regular professional care.” These can be helpful to people who live in nonfluoridated communities or whose teeth are very susceptible to decay. Toothbrushes Most dentists suggest a flat brushing surface with tufts of about equal length throughout the brush and a head small enough for comfort, regardless of the number of rows. The head of the brush must be small enough to reach all important surface areas of the mouth. Soft nylon bristles are flexible, clean teeth efficiently, and usually do not damage the gums. These bristles can make contact below the gum margin to help remove plaque. Toothbrushes with hard bristles should not be used because they can damage the teeth and gums, especially when combined with a highly abrasive toothpaste. To be effective, a brush must be manipulated properly. For manual brushing, the brush should be vibrated with the bristles positioned at a 45-degree angle against the gums so that one row of Figure 7-3. The ADA Seal of Acceptance. This logo, which signifies that a product meets ADA standards of safety and effectiveness, can be displayed in ads and on product labels and packages. More than 1300 over-the-counter and professional products are involved. Participating manufacturers must submit the products for expert evaluation and agree to have their advertising preapproved. Since 1994, this program has been administered by the ADA Council on Scientific Affairs. The ADA Web site has monographs for more than 300 consumer products at www.ada.org/seal. Part Two Health-Care Approaches118 bristles can slip slightly under the gum. All tooth surfaces should also be brushed twice a day. Electric toothbrushes are useful but are not pana- ceas. Careful manual brushing can be just as effective as mechanical brushing, although some studies report that certain electric toothbrushes remove plaque more efficiently than manual brushing. An electric toothbrush is particularly helpful for people with poor coordination caused by mental or physical disabilities, patients with orthodontic bands on their teeth, or people who are un- willing to spend sufficient time for proper brushing by hand. In recent tests, Consumer Reports 24 found that its top-rated Oral-B Triumph Professional Care 9400 and the Phillips Sonicare FlexCare R910 removed 75% of plaque. Consumers Union’s consultants advise replacing one’s toothbrush every 3 months because worn bristles are less effective at removing plaque. “Toothbrush sterilizers” have no practical value because there is no danger from using a toothbrush that carries germs from one’s own mouth. Interdental Cleaners Although the toothbrush is successful in removing plaque at exposed surfaces, it cannot completely clean the surfaces between the teeth. Optimal oral hygiene requires something that can penetrate between adjacent teeth. The products designed to do this include floss, woodsticks, rubber-tip simulators, interdental brushes, and irrigators. Dental floss comes waxed or unwaxed. Although many dentists recommend the unwaxed type as better for removing plaque, people with closely spaced teeth may find it easier to use the waxed type. The important point is to floss daily in the manner prescribed by the dentist or dental hygienist. Floss holders are available for people who have difficulty manipulating the floss by hand. When teeth are hard to floss because of bridgework or gum recession, dentists may recommend a specially shaped toothpick (such as Stim-u-dent) or a rubber in- terdental tip to supplement dental floss. Interdental brushes are small, specially designed brushes for cleaning between the teeth. They have soft nylon filaments twisted into a fine stainless steel wire. They are suitable for use by patients with sufficient space between their teeth.25 Oral irrigating devices use a direct spray of water to remove loose food particles and other large materials from around the teeth. Oral irrigators cannot substitute for either brushing or flossing, but patients with orth- odontic bands, a fixed bridge, or excessive spacing between the teeth may find them helpful. Incorrect use of an irrigating device can injure oral tissues. For this reason, persons using such devices should get instruc- tions from their dentist about proper use. Sugarless Gum Chewing gum that contains sugar can contribute to tooth decay. Thus sugar-free gum is a better choice for people who chew gum frequently. Gums that contain xylitol can help decrease the risk of decay.26 Xylitol, a sugar alcohol, inhibits the growth and acid-forming ability of the bacteria (Mutans streptococci) that contribute to tooth decay. The American Academy of Pediatrics (AAP) recommends that pregnant women chew xylitol gum or mints 4 times a day to prevent or delay transmission of these bacteria to their infants. The American Academy of Pediatric Dentistry recommends that young children use the gum, but the AAP is concerned about the risk of choking and has not endorsed the practice.27 Mouthwashes Advertising has suggested that mouthwashes are effec- tive against bad breath (halitosis), can help clean the teeth, prevent or treat colds and sore throats, and help control dental plaque. Many such promotions have been misleading. Mouthwashes can freshen the breath for a few min- utes (sometimes as much as an hour), but they cannot prevent infectious diseases. Those that kill bacteria may reduce bad breath if used regularly.28 Some mouth- washes have a high alcohol content, which can cause excessive drying of the mouth. People who are troubled with bad breath should understand that this is a symptom whose cause, whether oral or systemic, should be ascertained. The common causes of halitosis include poor oral hygiene; postnasal drip; gum disease; tobacco use; and consumption of gar- lic, onions, certain alcoholic beverages, or other aromatic substances that are exhaled from the lungs and are not subject to modification by mouthwash. Halitosis can also be a symptom of infections, tumors, diabetes, and various other diseases. For many years—until stopped by federal enforce- ment actions—manufacturers suggested in their ads that mouthwashes could help prevent or cure infections. It is true that antiseptic mouthwashes can kill some germs on contact, but this has not been proven to prevent in- fections. Germs in the tiny crevices in the mouth and within infected tissues cannot be reached or washed out. Germs that are washed off the surface of infected areas are quickly replaced. Chapter Seven Dental Care 119 The plaque-control situation is less clear-cut. In 1986 the FDA approved Peridex mouth rinse, a prescription drug that contains 0.12% chlorhexidine, as safe and effective in helping to control plaque. Chlorhexidine, which has antibacterial action, can reduce plaque be- low the gumline. In 1987 the ADA Council on Dental Therapeutics concluded that: “Listerine Antiseptic has been shown to help prevent and reduce supragingival (above the gumline) plaque accumulation and gingivitis when used in a conscientiously applied program of oral hygiene and regular professional care. It has not been shown to have a therapeutic effect on periodontitis.” Listerine (a nonprescription product), which works mainly by washing away bacteria, has little or no effect on plaque below the gumline and is not nearly as effec- tive as Peridex. Mouthwashes are not substitutes for brushing and flossing and are appropriate mainly for individuals under dental care in which other measures are unable to control gingivitis. Plax, another mouthwash claimed to reduce plaque, uses sodium benzoate as its principal ingredient. A 2002 meta-analysis concluded that although Plax use appeared to offer some benefit in plaque and gingivitis reduction, the effect and benefit on oral health are likely to be small.29 Some studies have suggested that mouthwash with a high alcohol content is associated with an increased risk of oral and oropharyngeal cancer. However, recent research has found these studies to be flawed, pointing out that smokers and frequent drinkers (who are there- fore already at increased risk) are likely to use more mouthwash than people who neither smoke nor drink. Do-It-Yourself Bleaching Dentists have been bleaching teeth in their offices for decades. This is a legitimate procedure that requires care to ensure that the patient is not injured by the caustic bleaching agent. The tooth whitening marketplace has four categories: (1) professionally applied, (2) dentist- prescribed for home-use, (3) over-the-counter (OTC) applied by patients, and (4) nondental options such as mall kiosks, salons, spas, and cruise ships. In addition, dentist-dispensed bleaching materials are sometimes used at home after dental-office bleaching to maintain or improve whitening results. The ADA Council on Therapeutics urges caution about bleaching that is not professionally supervised: Tooth bleaching is one of the most conservative and cost- effective dental treatments to improve or enhance a person’s smile. However, tooth bleaching is not risk-free and only limited long-term clinical data are available on the side ef- fects of tooth bleaching. Accordingly, tooth bleaching is best performed under professional supervision and following a pre-treatment dental examination and diagnosis. . . . Patients considering OTC products should have a dental examination, and should be reminded that they may unknow- ingly purchase products that may have little or no beneficial effect on the color of their teeth and may also have the potential to cause harm.30 Pain Relievers People with toothaches sometimes seek temporary relief by applying a nonprescription pain reliever to the teeth. These products usually contain clove oil, anesthetics, and aspirin. Clove oil is a powerful germicide. It is uncertain whether the relief it provides is due to a local anesthetic effect or its irritant activity. Anesthetics such as benzocaine and butane sulfate can provide minor relief from pain, if the decayed area of the tooth is exposed and accessible. Aspirin does not provide topical anesthesia. It should never be packed into a carious tooth or placed onto the adjacent gum because its acidic nature can traumatize a nerve ending and severely burn the mucous membrane of the mouth. Ibuprofen or naproxen, taken internally, can be effective against dental pain. Dental restorations The most common material used to restore decayed teeth is amalgam, a tightly-bonded mixture of mercury and an alloy of silver, tin, copper, and zinc. Tooth-colored plastic (composite) fillings can be used in front teeth or for small, visible back fillings. Amalgam fillings are less expensive, more durable, and easier to replace than composite fillings.31,32 If much tooth structure has been lost as the result of decay or an accident, then a cast restoration is used, preferably gold. A cemented restoration that covers only part of the tooth is called an inlay or onlay. Cast metal, porcelain, and composite plastic materials can be used for this purpose. When not enough tooth is present to hold an inlay, a crown is attached to the stump to restore the ap- pearance of the entire tooth above the gumline. Crowns are usually made of a combination of metal (preferably gold or palladium alloy) and porcelain. A front crown, sometimes called a cap, is sometimes solid porcelain. When teeth are missing, teeth on either side of the space can be crowned and artificial teeth (a bridge) can be permanently fastened to the crowns. A bridge cemented to adjacent teeth is called a fixed bridge. Fixed bridge- work is generally superior to removable bridgework, but there are situations where it cannot be used. Part Two Health-Care Approaches120 The resin-bonded (Maryland) bridge, a type of fixed bridge developed by researchers at the University of Maryland, uses special materials that bond metal to tooth structures. This method enables the dentist to re- place missing teeth with a cemented restoration, without placing crowns on the adjacent teeth. It costs less than a conventional fixed bridge, but it is not as durable. “Drill-less Fillings” The Caridex is a trademarked device that uses a warm solution of sodium hydroxide, sodium chloride, sodium hypochlorite, and aminobutyric acid as its active ingredi- ent to soften decay so that it is easily scraped from the tooth with a metal instrument. This procedure is safe and allows some patients to be treated without an injection of anesthetic. However, most cavities are not sufficiently exposed, so drilling is still needed for the great major- ity of patients. The Caridex is very slow and therefore increases the cost of performing a filling. Bonding Bonding is a popular method of correcting cosmetic problems in patients with healthy gums and adequate tooth structure to which bonding material can be applied. Most dentists employ this procedure. Bonding is not an alternative to crowning. Crowns are needed if teeth are badly broken down or must anchor a bridge. To prepare a tooth for bonding, an acid solution is applied to increase adhesion. A liquid plastic is then painted on, and a paste made of plastic and finely ground quartz, glass, or silica gel is layered onto the tooth. Each layer is hardened in minutes either chemically or by shining a very bright light on the p

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