Section 2. Chapter 11: Using Preventive Agents

3. For each chemotherapeutic agent listed, select the MOST closely linked description on the agent's use from the list provided.

ANS: 1H; 2F; 3B; 4G; 5C; 6E; 7I; 8A; 9D. Calcium and phosphate in saliva (1H) are involved in the remineralization process. The addition of calcium and phosphate to oral products is designed to enhance remineralization. Two professionally dispensed products are MI paste and NuvaMin. Hydrogen peroxide (2F) is used as an oxygenating mouth rinse for antimicrobial effect to reduce gingivitis and malodor, and in the treatment of NUG. Various soluble pyrophosphate formulas (3B) have an anticalculus effect by inhibiting crystal growth to retard calculus formation. These agents are only effective on supramarginal calculus formation because of the different natures and locations of supragingival and subgingival calculus. Quaternary ammonium compounds (4G) are mouth rinses that bind to oral tissues. Side effects include increased calculus formation, occasional burning sensation, and epithelial desquamation. The most common quaternary ammonium compound is cetylpridinium chloride, contained in Cepacol, Scope, and Crest Pro-Health mouth rinses. Its mechanism of action is the rupture of bacterial cell walls and alteration of cytoplasmic contents. Recaldent (5C) is a complex of casein phosphopeptides and amorphous calcium phosphate, derived from milk protein. Available as a chewing gum, it is used to manage dental caries by enhancing remineralization. Those patients with inadequate saliva are likely to benefit from the availability of increased calcium and phosphate. Sodium fluoride (6E) is the only fluoride used for both water fluoridation and in professionally applied fluoride treatments. Sodium bicarbonate (7I) is used to neutralize acid from acid reflux and after vomiting in patients with bulimia or those undergoing chemotherapy. It should be used as soon as possible after the acid attack and is especially recommended to manage dental caries in patients who have inadequate saliva. It is available as a chewing gum and dentifrices or can be used by 619 rinsing with two teaspoons of baking soda mixed in 8 ounces of water, in which case it should not be swallowed to minimize the ingestion of excessive sodium. Stannous fluoride (8A) is added to dentifrices to control gingivitis, dental caries, and hypersensitivity. At the low dose required for dentifrices, staining is not usually a problem. Triclosan (9D) is a broad-spectrum antimicrobial detergent agent with antiplaque, anti-gingivitis, and anti-inflammatory actions when added to dentifrices. Triclosan is the active antimicrobial agent in Colgate Total dentifrice and is approved by the U.S. Food and Drug Administration (FDA) and accepted by the American Dental Association (ADA) to treat gingivitis.

55. Continuous use of fluoridated water from birth may result in 40% to 65% fewer carious lesions. Anterior teeth, particularly maxillary anterior teeth, receive more protection from fluoride compared with posterior teeth because of the direct contact of drinking water as it passes into the mouth and earlier eruption dates. A Both statements are true. B Both statements are false. C The first statement is true, and the second statement is false. D The first statement is false, and the second statement is true.

ANS: A Both statements are true (A). Continuous use of fluoridated water from birth may result in 40% to 65% fewer carious lesions, with many more individuals being caries free when fluoride is in the water. Anterior teeth, particularly maxillary anterior teeth, receive more protection from fluoride compared with posterior teeth because of the direct contact of drinking water as it passes into the mouth. **Choices B, C, and D do not accurately reflect the statements.

39. Sealant material often contains filler particles. The purpose of the filler is to make the sealant more resistant to abrasion and wear. A Both statements are true. B Both statements are false. C The first statement is true, and the second statement is false. D The first statement is false, and the second statement is true.

ANS: A Both statements are true (A). Filled sealant material usually contains the same or similar filler materials as composite resins: glass beads, quartz, or other particles. The filler particles themselves are slightly more resistant to abrasion and wear, and when combined in a resin-based sealant, they create a more resilient material that can withstand masticatory forces better. **Choices B, C, and D do not accurately reflect the statements.

12. The emphasis in toothbrushing instruction to prevent and control gingivitis and mild to moderate periodontitis should be on developing and maintaining an effective technique. The emphasis on toothbrushing to prevent and control dental caries should be on increasing the frequency and duration of brushing with fluoride toothpaste. A Both statements are true. B Both statements are false. C The first statement is true, and the second statement is false. D The first statement is false, and the second statement is true.

ANS: A Both statements are true (A). The effectiveness of toothbrushing technique is important to maximize biofilm removal to prevent and control gingivitis and periodontitis. The addition of fluoride dentifrice aids in removal of plaque biofilm and increases the resistance of the enamel to acid attack. Increasing the frequency and duration of toothbrushing increases the bioavailability of the fluoride to enhance remineralization, prevents demineralization, and increases the antimicrobial effect. **Choices B, C, and D do not correctly reflect the statements.

48. The purpose of converting neutral sodium fluoride into acidulated phosphate fluoride is to lower the pH of the product. Evidence-based research indicates that a pH of 4 or lower enhances fluoride uptake. A Both statements are true. B Both statements are false. C The first statement is true, and the second statement is false. D The first statement is false, and the second statement is true.

ANS: A Both statements are true (A). The primary purpose of converting neutral sodium fluoride to acidulated phosphate fluoride is to lower the pH of the product, which increases fluoride uptake into the enamel surface. Neutral sodium fluoride has a pH of around 7, and acidulation drops the pH to 3 to 5. Evidence-based research indicates that a pH of 4 or lower enhances fluoride uptake. **Choices B, C, and D do not accurately reflect the statements.

28. Detergent ingredients in dentifrices help loosen debris through their foaming action. An example of a detergent is sodium lauryl sulfate. A Both statements are true. B Both statements are false. C The first statement is true, and the second statement is false. D The first statement is false, and the second statement is true.

ANS: A Both statements are true (A). The purpose of adding a detergent agent to a dentifrice is to help loosen debris, produce a foaming action, and act as a surfactant. Sodium lauryl sulfate is the most commonly utilized detergent for dentifrices. **Choices B, C, and D do not accurately reflect the statements.

35. Sugar-free gums primarily use xylitol or sorbitol for their sweetening agents. Chewing gum may be a useful home care recommendation to stimulate saliva. A Both statements are true. B Both statements are false. C The first statement is true, and the second statement is false. D The first statement is false, and the second statement is true.

ANS: A Both statements are true (A). Xylitol, sorbitol, mannitol, and erythritol are useful sweeteners for chewing gum because they are not metabolized by oral bacteria, nor can they be used to produce acid byproducts. Chewing gum stimulates saliva that buffers acids in the mouth and enhances remineralization. Research indicates that chewing xylitol gum specifically additionally reduces the population of cariogenic bacteria. When saliva is stimulated with xylitol gum, it buffers acids secreted by the oral flora; works to flush and rinse debris from teeth; lubricates oral tissues; maintains calcium, phosphate, and other ion levels; and has antibacterial effects. Research has shown that xylitol effectively reduces caries incidence when used in sufficient quantities (6 to 10 g of xylitol gum, chewed three to five times per day). **Choices B, C, and D do not accurately reflect the statements.

24. School water fluoridation requires adjustment of the amount of fluoride to four to five times the optimal level that is required to fluoridate the community water supply. School water fluoridation is no longer recommended by the Centers for Disease Control and Prevention (CDC). A Both statements are true. B Both statements are false. C The first statement is true, and the second statement is false. D The first statement is false, and the second statement is true.

ANS: A Both statements are true. School water fluoridation requires adjustment of the amount of fluoride to 4.5 times the optimal level of fluoride that is required to fluoridate the community water supply. This is based on the fact that children consume less water at school because they are in school only part of the day, a portion of the week, and some of the months. The second statement is true. School water fluoridation is no longer recommended by the CDC for two reasons. The increase in community water fluoridation in the United States and the increase of fluoride availability from other sources have reduced the need for school water fluoridation. In addition, quality assurance for school water fluoridation is more difficult than community water fluoridation, which has resulted in fluoride spills into the water that produced excessive levels of fluoride in the school water supply. **Choices B, C, and D do not accurately reflect the statements.

11. Pit and fissure sealants should be used in combination with fluorides for prevention of other types of caries because they are primarily effective in preventing pit and fissure caries. A Both the statement and reason are correct and related. B Both the statement and reason are correct but not related. C The statement is correct, but the reason is not. D The statement is NOT correct, but the reason is correct. E NEITHER the statement NOR the reason is correct.

ANS: A Both the statement and the reason are correct and related (A). Sealants are directed toward the prevention of pit and fissure caries. Fluorides have the greatest effect in the prevention of smooth surface caries. Combining both preventive measures provides a comprehensive approach for prevention of tooth decay. **Choices B, C, D, and E do not accurately reflect the statements.

6. All the following are effective ways to control volatile sulfur compounds (VSC)-producing organisms that cause breath malodor EXCEPT one. Which one is the EXCEPTION? A Using breath mints B Brushing the tongue C Rinsing with Listerine D Using a tongue scraper

ANS: A Breath mints (A) will help to mask breath malodor but will not impact the VSCs. Research indicates that 80% to 90% of oral malodor originates from the oral cavity. **Oral malodor is caused by VSCs, which are byproducts of bacterial metabolism. Use of chemotherapeutic agents such as Listerine (C) that neutralize VSCs, combined with brushing the tongue (B) or using a tongue scraper (D), is effective against malodor if it has an oral cause.

4. Which of the following additives has been shown to control dental caries by preventing the transmission of cariogenic bacteria from mother to infant? A Xylitol B Sorbitol C Triclosan D Stannous fluoride E Hydrogen peroxide

ANS: A Chewing xylitol (A) gum in adequate amounts by mothers of young children in the first 2 years of the children's lives prevented the vertical transmission of cariogenic bacteria from caregivers to infants. **Sorbitol (B) is a nutritive sweetener that does not promote tooth decay but has not been proven to prevent the transmission of cariogenic bacteria from mother to infant. **Studies have not found this protective effect is not seen with triclosan (C), stannous fluoride (D), or hydrogen peroxide (E).

38. If a sealant was lost within the first couple of months after application, which would be the MOST likely cause of failure? A Operator error B Carious lesions C Expired materials D Patient compliance

ANS: A Failure to obtain sealant retention for longer than 3 to 6 months is almost always related to an error on the part of the operator or clinician (A). Inability to keep the field moisture free during the actual application of the sealant often has been the primary causative factor in retention failure. **A carious lesion (B) would not contribute to failure of a sealant; instead, studies have demonstrated that many times a sealant will arrest the progression of an incipient lesion. **Expired materials (C) are less likely to cause sealant failure than operator error. **Patient compliance (D) may increase the difficulty of keeping a dry field during placement, but an effective operator should be able to employ effective patient management to place the sealant effectively.

13. Which of the following foods naturally contains the MOST fluoride? A Fish and tea B Meats and eggs C Milk and cheese D Fruits and vegetables

ANS: A Fish from the sea naturally contains 1 part per million (ppm), and black tea contains from 1 to 6 ppm of fluoride (A). Fluoride is a naturally occurring compound in water and soil, so all foods contain some fluoride, especially those grown in soil that is irrigated with fluoridated water. **However, the amounts of fluoride provided in meats (B), dairy products (C), and fruits and vegetables (D) are insignificant.

64. Which of the following self-care devices is most appropriate for plaque biofilm removal from proximal tooth surfaces and shallow pockets? A Dental floss B Toothpicks C End-tuft brushes D Powered toothbrush

ANS: A Plaque biofilm removal from proximal tooth surfaces and shallow pockets is best accomplished with dental floss (A). **Before recommending interdental self-care devices such as toothpicks (B) or end-tuft brushes (C), the dental hygienist should consider the contour and consistency of the gingival tissues, gingival attachment levels, and size of the embrasures. **Powered toothbrushes (D) are not effective in cleaning proximal tooth surfaces thoroughly.

29. A patient presents with sloughing of the oral mucosa that has been present for 1 week and wonders why his gingival tissue is peeling. Which is the MOST likely cause for the patient's condition? A Allergic reaction B Brushing too vigorously C Inadequate toothbrushing D Oral manifestation of a new systemic condition

ANS: A Sloughing is most likely a result of an allergic reaction to a product (A), frequently a flavoring, preservative, whitening agent, mouth rinse product, or detergent agent in a dentifrice. The patient should be questioned as to whether there has been a recent change in the brand of oral care product to determine whether that is the causative agent for the condition. Studies have found that the detergent sodium lauryl sulfate may cause mucosal irritation in some individuals. Cinnamon flavoring is another common allergen. **Too vigorous brushing results in trauma, not sloughing (B). **Inadequate toothbrushing results in gingival erythema and bleeding (C). **Although it is possible that the sloughing is a result of an oral manifestation of a new systemic condition, this occurs less frequently than allergic reactions to products (D).

31. All of the following are important considerations for a mouth rinse marketed for xerostomia EXCEPT one. Which one is the EXCEPTION? A Is non staining B Contains fluoride C Has lubricating properties D Has moisturizing qualities

ANS: A Stain (A) is a cosmetic concern and holds no pathologic effects; if a xerostomia mouth rinse causes staining, the stain is easily removed during a patient's routine oral prophylactic treatment. **Reduction in saliva results in an increased risk for dental caries because of the important role the saliva has in re-mineralizing areas of demineralization, so the addition of fluoride (B) helps offset caries risk. **Xerostomia mouth rinses are designed to provide artificial lubrication (C) to the oral cavity while supplementing the moisturizing qualities (D) of saliva.

26. Which of the following is the LOWEST probable toxic dose (PTD) of fluoride for a child who weighs 20 kilograms? A 100 mg fluoride or 640 g NaF B 200 mg fluoride or 1280 g NaF C 640 mg fluoride or 100 g NaF D 1280 mg fluoride or 200 g NaF

ANS: A The PTD is the same as the estimated lethal dose. It is the dose that will cause toxic signs and symptoms and possibly death and should trigger therapeutic intervention and hospitalization. The PTD is 32 to 64 mg fluoride or 5 to 10 g (50 to 100 mg) NaF/kg body weight (1 kg = 2.20 pounds) (A). At the low end of this range for a child who weighs 20 kg, the PTD would be 640 mg fluoride or 100 g NaF (32 × 20 = 640; 5 × 20 = 100). The amount contained in some self-administered products is the PTD for young children. Therefore, the ADA recommends that the amount of fluoride in these fluoride products that are kept in the home be controlled. There is a need for parent education and parental supervision with the use of these products to prevent children from consuming a toxic dose. **The higher levels in choices B, C, and D do not accurately reflect the question.

62. Smokeless or spit tobacco education should include all the following teaching points EXCEPT one. Which one is the EXCEPTION? A Causes vasodilation B Affects leukocyte migration C Fosters persistence of pathogens D Increases severity of periodontal disease

ANS: A The use of smokeless or spit tobacco causes vasoconstriction (A) of blood vessels (not vasodilation), which may compromise periodontal wound healing and repair. **Patients should also be advised that use of smokeless or spit tobacco affects leukocyte migration (B) and fosters persistence of pathogens (C), which can result in increases in the severity of periodontal disease (D).

18. When the fluoride ion replaces the hydroxyl ion in the enamel structure, which of the following is the MOST stable result? A Fluorapatite B Hydroxyapatite C Carbonated apatite

ANS: A When the fluoride ion replaces the hydroxyl ion in the hydroxyapatite of enamel, the resulting fluorapatite (A) crystal becomes more stable and less soluble. **Fluorapatite is very resistant to dissolution by acid. **Hydroxyapatite (B) is the pure form of minerals in calcified structures such as enamel, dentin, alveolar bone, cementum, and even calculus. **However, in reality, hydroxyapatite exists in dental structures as carbonated apatite (C), in which it has been contaminated by carbonate and other minerals that make the tooth structure more soluble in plaque acids.

36. Which of the following situations are indications for placement of a dental sealant? (Select all that apply.) A Adeep occlusal fissure B An incipient Class I carious lesion C A deep dentinal Class I carious lesion D Shallow fissures in an adult with no history of caries

ANS: A, B Indications for dental sealants include deep pits, fissures, and shallow fossae so that bacteria, particularly Streptococcus mutans, cannot be harbored for growth (A). Research indicates the safety of sealing over incipient lesions as a way of arresting progression of the carious lesion (B). **A deep dentinal Class I carious lesion (C) needs to have a conventional restoration, as a sealant is insufficient to stop advanced caries. **Shallow fissures in an adult with no history of caries (D) are not an indication for sealants because the caries risk is extremely low in this patient.

22. Which of the following are benefits of water fluoridation? (Select all that apply.) A Greater overall oral health B Reduction of childhood caries C Savings in dental treatment costs D Reduction in cases of oral cancer E Lower rates of coronal and root caries in adults

ANS: A, B, C, E There are many benefits of water fluoridation. Reduction of caries results in lower rates of tooth loss, which is a factor in periodontal health and prevention of malocclusion, resulting in improvements in overall oral health (A). Water fluoridation is strongly correlated to reduction of childhood caries (B). Prevention of caries translates to savings in dental treatment costs for both individuals and governmental agencies (C). The primary action of fluoride is post-eruptive, so lower rates of coronal and root caries in adults are a benefit of water fluoridation (E). **Water fluoridation is not related to reduction in cases of oral cancer (D).

33. Which of the following characteristics represent ideal properties of an antimicrobial mouth rinse? (Select all that apply.) A Substantively B No adverse reactions C Promotes microbial resistance D Targets pathogenic microflora

ANS: A, B, D Chemotherapeutic agents are useful as a supplement to manual plaque removal. Ideal characteristics include: substantivity, or the ability to be slowly released over time for increased (A); FDA approval, which signifies that the products have demonstrated safety with the absence of adverse reactions in multiple clinical trials (B); and inhibition of plaque formation and growth, specifically targeting pathogenic microflora and sparing the normal microflora (D). **Chemotherapeutic agents should not promote microbial resistance (C), which would render the agent ineffective against pathogenic microorganisms.

49. Which of the following items are considered antibacterial agents for dental caries? (Select all that apply.) A Xylitol B Chlorhexidine C Dental sealants D Sodium bicarbonate E Carbamide peroxide

ANS: A, B, D, E Xylitol (A) is a sweetener that looks and tastes like sucrose but has the ability to inhibit attachment and transmission of bacteria. Chlorhexidine gluconate (B) is a broad-spectrum antibacterial agent that works by disrupting the cell membranes of bacteria. Sodium bicarbonate (D) neutralizes acids produced by acidogenic bacteria and has antibacterial properties. Carbamide peroxide (E) is found in botanical-based mouth rinses as well as serving as bleaching agent for teeth. **Dental sealants (C) are physical barriers that prevent plaque bacteria from entering pits and fissures but are not considered antibacterial agents.

46. Which of the following formulations are considered professionally applied fluoride products and have been approved by the FDA for in office use? (Select all that apply.) A 2.0 % sodium fluoride B 1.1% sodium fluoride C 5% sodium fluoride varnish D 8.0% stannous fluoride solution E 1.23% acidulated phosphate fluoride

ANS: A, C, D, E The four high-potency topical fluoride systems that have been approved by the FDA for in-office use are 2.0% sodium fluoride (A), 5% sodium fluoride varnish (C), 8.0% stannous fluoride (D), and 1.23% acidulated phosphate fluoride (E). **The remaining choice, 1.1% sodium fluoride (B) is for home care and is available over-the counter or in the dental office.

44. Which of the following strategies serve as effective patient management tools during sealant placement in children? (Select all that apply.) A Use an assistant whenever possible. B Have the parent stay in the treatment area. C Keep the child distracted and calm through conversation. D Have all supplies and materials ready before seating the child. E Employ the "Tell, Show, Do" strategy to avoid any surprises.

ANS: A, C, D, E Using an assistant improves time management to enhance patient comfort and maximizes the effectiveness of moisture control to ensure long-term retention of the sealant (A). Keeping the child distracted and calm through conversation (C) is another technique for gaining cooperation with the child during the sealing process. Children have a much shorter attention span compared with adults, so being organized by having all supplies and materials ready before seating the child for a sealant procedure prior to seating is beneficial (D). Employing the "Tell, Show, Do" strategy of explaining, showing on models, and demonstrating the procedure to prevent any surprises orients children and helps calm any anxiety they might have about receiving sealants (E). **Having the parent stay in the treatment area (B) is not always helpful because the child may focus attention on the parent rather than paying attention to the dental hygienist.

69. A female patient reports an allergic reaction when wearing certain types of jewelry. Which of the following agents should be reduced in the fabrication of her new crown for tooth #30? A Zinc B Nickel C Copper D Chromium

ANS: B As a preventive measure, the fabrication of the new crown should include the reduction of nickel (B) as part of its composition because nickel has the highest incidence of allergic response. **Zinc (A), copper (C), and chromium (D) are more biocompatible with oral tissues and less likely to cause an allergic response.

9. Which of the following dentifrice ingredients should be avoided if a nonabrasive dentifrice is recommended? A Triclosan B Baking soda C Stannous fluoride D Carbamide peroxide

ANS: B Baking soda (B) as a dentifrice ingredient in whitening toothpastes and should be avoided if a nonabrasive dentifrice is recommended. **Triclosan (A) is added to dentifrices as an antibacterial agent and is nonabrasive. **Stannous fluoride (C) is added to dentifrices as an anti-caries, antibacterial, and desensitizing agent, but is not an abrasive ingredient. **Carbamide peroxide (D) is added to whitening toothpastes but is not abrasive.

70. Which of the following conditions would indicate bonded retainer failure? A Occlusal wear B Tooth mobility C Presence of biofilms D Stripping of attached gingiva

ANS: B Bonded retainers are designed to stabilize teeth and to control orthodontic alignment; therefore tooth mobility (B) would be a sign of retainer failure. **Occlusal wear (A), the presence of biofilms (C), and the stripping of attached gingiva (D) are not signs of retainer failure.

42. When preparing a tooth for sealant placement, the amount of time required for the acid etchant to remain in place depends on the operator's clinical judgment. If the tooth surface presents with a white chalky or frosty appearance on drying after rinsing the etchant, it is a good clinical indicator that the etching period was insufficient and should be repeated. A Both statements are true. B Both statements are false. C The first statement is true, and the second statement is false. D The first statement is false, and the second statement is true.

ANS: B Both statements are false (B). It is imperative to follow manufacturer's directions, not operator judgment, for using the acid etchant during sealant application. Although some variance exists among products, generally the etching time is 20 to 30 seconds. A white chalky or frosty appearance after rinsing and drying indicates that sufficient time was allowed for etching and that enough enamel tags have been created on the surface to adequately retain the sealant after placement. **Choices A, C, and D do not accurately reflect the statements.

37. Which of the following BEST describes the purpose of using an etchant or tooth conditioner during the sealant application process? A Bonds the sealant material to the tooth B Increases the surface area for the sealant material C Removes debris and stain from the surface to be sealed D Enhances uptake of fluoride from the sealant material

ANS: B Etching the enamel with 35% to 37% orthophosphoric acid removes the outer 5 to 10 micrometers of enamel, creating an uneven, roughened surface. The irregularities in the surface are termed tags, and they increase the surface area for the sealant material (B), increasing adhesion of the sealant to the tooth and enhanced long-term retention. **Etchants do not bond the sealant to the tooth (A) because sealants are retained by micromechanical retention using the enamel tags. **Etchants are not the appropriate material for cleaning the surface of the tooth before sealant placement (C); most manufacturer instructions recommend using a pumice flour paste or air polishing for debris removal. **The etchant does not contribute to fluoride adsorption by the tooth (D), fluoride slowly leaches from the sealant material into the surrounding enamel over time.

8. Which of the following is considered the major mechanism of action of fluoride in the inhibition of dental caries progression? A Antimicrobial effect on acidogenic bacteria B Enhancement of remineralization in the demineralization- remineralization cycle C Formation of fluorapatite during the development of enamel prior to eruption D Inhibition of demineralization through fluoride adsorption by enamel mineral crystals

ANS: B Fluorides enhance the remineralization of enamel in the continual demineralization-remineralization cycle (B), and this post eruptive remineralization is believed to be the major mechanism of action of fluoride in the inhibition of dental caries progression. **Other benefits include fluoride's antimicrobial effect on acidogenic bacteria (A), the formation of fluorapatite during the development of enamel prior to eruption (C), and inhibition of demineralization through fluoride adsorption by the enamel mineral crystals (D). The salivary level of fluoride is the critical factor in these post eruptive benefits. Water fluoridation continues to have a post eruptive topical effect because it is excreted into the saliva.

1. Which of the following statements describes the incorporation of chemotherapeutic agents in the control of bacterial components of plaque biofilm? A Replaces brushing and flossing B Supplements brushing and flossing C Recommended for use by all patients D No antibacterial role in plaque biofilm control

ANS: B Incorporation of chemotherapeutic agents in plaque biofilm control is always recommended as a supplement to brushing and flossing (B). **Chemotherapeutic agents are never a replacement for brushing and flossing (A). The use of chemotherapeutic agents is recommended when regular and routine oral hygiene care is insufficient to control gingivitis, dental caries, or malodor, based on the level of risk of the patient and the effectiveness of oral hygiene. **With high-risk patients, chemotherapeutic agents are recommended to control the bacterial components of biofilm (C). **Patients who practice effective oral hygiene and are in a low-risk category for periodontal diseases and dental caries do not need chemotherapeutic agents to control these diseases (D).

21. Mild to moderate fluorosis occurs at which of the following parts per million (ppm) levels? A < 1 ppm B > 2 ppm C > 5 ppm D > 10 ppm

ANS: B Mild to moderate fluorosis occurs at levels of greater than 2 ppm (B). The ideal level of fluoride in community water supplies is 0.7 ppm for all geographic locations in the United States. The Environmental Protection Agency (EPA) recommends de-fluoridation if water supplies have a fluoride level greater than 2 ppm. **At levels less than 1 ppm (A), fluorosis is rare. **Levels of fluoride greater than 5 ppm (C) and 10 ppm (D) will result in severe fluorosis in most populations. The EPA mandates de-fluoridation if water supplies contain greater than 4 ppm of fluoride.

58. Which of the following preventive measures can be beneficial in the reduction of anterior disc displacement (RADD) and/or control the symptoms? A Oral surgery B Occlusal splint C Occlusal adjustment D Orthodontic treatment

ANS: B Occlusal splint (B) therapy can be beneficial in the treatment or prevention of RADD and restoring normal jaw function such as chewing and talking. **Oral surgery (A) is a treatment choice rather than a preventive control measure. **Occlusal adjustment (C) and orthodontic treatment (D) are not beneficial in the treatment or prevention of RADD.

54. During the placement of dental sealants, which of the following is used as an etching agent? A 25% phosphoric acid B 35% phosphoric acid C 10% carbamide peroxide D 15% carbamide peroxide E 15% hydrogen peroxide

ANS: B Once isolated, cleaned and dried, the enamel surface is etched with a solution of 35% to 50% phosphoric acid (B). **Carbamide and hydrogen peroxide solutions (C, D, E) are used for bleaching, whereas 25% phosphoric acid (A) is not the standard concentration used in dentistry.

68. A 65-year-old patient with a history of uncontrolled high blood pressure who is currently taking medication to lower blood pressure and a diuretic presents for an emergency dental appointment. Which of the following preventive agents is safe for this patient? A Sugar B Oxygen C Norepinephrine D General anesthesia

ANS: B Oxygen (B) is the appropriate preventive agent for this patient, as it will lower the blood pressure. **This is designed to prevent hypoxia, which can cause an increase in blood pressure. **Sugar (A) may be appropriate for a patient in a hypoglycemic emergency. **Norepinephrine (C) is not available for use as a vasoconstrictor in the United States. **Some patients with severe hypertension may be excluded from safe use of general anesthesia (D) as per the American Society of Anesthesiologists (ASA).

17. Which of the following first aid steps should be taken FIRST if a child swallows a toxic dose of fluoride? A Have the child drink milk B Induce vomiting C Administer cardiopulmonary resuscitation (CPR) D Administer oxygen

ANS: B The first step in the administration of first aid if a child swallows a toxic dose of fluoride is to empty the stomach of excess fluoride by inducing vomiting (B). **Any fluoride remaining in the stomach can be neutralized by having the child ingest a calcium-rich product such as a glass of milk (A) or calcium antacids, which will chemically bind with the fluoride so it will not be absorbed into the bloodstream. **Symptoms depend on the amount swallowed and include increased salivation, nausea, vomiting, abdominal pain, diarrhea, cramps, cardiac arrhythmia, and coma, resulting in death if not treated. If symptoms continue, the emergency medical services (EMS) should be activated; the individual should be taken to the hospital, and the stomach may have to be pumped. CPR (C) and oxygen (D) would only be necessary if early first aid measures fail.

67. Which of the following is the primary purpose of a mandibular advancement device (MAD)? A Eliminate bruxism B Increase upper airway volume C Replace positive airway pressure D Retain tongue in forward position

ANS: B The primary purpose of a mandibular advancement device (MAD) is to increase upper airway volume (B) for patients with sleep-related breathing disorders. **Although use of MADs may eliminate or reduce bruxism (A) and may be used to replace cumbersome positive airway pressure (C) mechanisms, these are not the primary purposes of the oral device. **Specific tongue-retaining devices (TRDs) are used to retain the tongue in a forward position (D), thus opening the airway.

57. Which of the following conditions can be prevented by a fixed or removable prosthodontic appliance? A Impaction B Supra-eruption C Occlusal reduction D Periodontal disease

ANS: B Tooth replacement with a fixed or removable prosthodontic appliance can prevent the occurrence of supra erupted teeth (B) in the opposing arch. **Placement of a prosthodontic appliance will not prevent tooth impaction (A). **Occlusal reduction (C) is a therapeutic procedure that aids in occlusal adjustments. **Periodontal disease (D) is caused by biofilm and prevention occurs through biofilm reduction and removal.

34. Which of the following products are commonly associated with staining of teeth, tongue, and tooth-colored restorations? (Select all that apply.) A Listerine B Chlorhexidine C Stannous fluoride D Crest Pro-Health

ANS: B, C, D Chlorhexidine (B) is notable for brown staining of teeth, tongue, and tooth-colored restorations. Stannous fluoride (SnF2) (C) may produce an extrinsic black line stain when used for therapeutic purposes. Crest Pro-Health mouth rinse (D), with Cetylpyridinium chloride (CPC), stannous fluoride, and sodium hexametaphosphate as active ingredients, has been connected with light extrinsic staining with long-term use. **Listerine (A) is generally NOT associated with staining.

51. Which of the following are the methods of classification for sealants? (Select all that apply.) A Cost B Color C Placement site D Sealant content E Polymerization method

ANS: B, D, E Sealants are classified by their color, which may be clear, tinted, or opaque (B); their content, which may be filled, unfilled, or glass ionomer (D); and by their method of polymerization, which may be either autopolymerization or photopolymerization (E). **Cost (A) and placement site (C) are not considered in sealant classification.

19. Which of the following statements is MOST correct regarding the benefits of water fluoridation? A The benefits of water fluoridation continue even after it is discontinued. B Water fluoridation does not benefit adults because their teeth have already erupted. C Partial exposure to water fluoridation provides benefits in proportion to the amount of fluoride in the water. D Because of current multiple exposures to fluorides, water fluoridation is no longer considered cost effective and is not recommended by public health experts.

ANS: C Even in suboptimal levels of water fluoridation, there are still benefits in proportion to the amount of fluoride in the water (C). **Further, even in children who receive the secondary pre-eruptive benefits during tooth development, the caries reduction benefits of water fluoridation do not remain if it is discontinued because the primary action of the fluoride occurs in the post-eruptive period through the salivary reservoir of fluoride (A). It was once believed that the primary action of systemic fluoride consumption was pre-eruptive, in which case adults would have limited benefit from water fluoridation. **However, currently, the evidence for the post-eruptive action of fluoride is much stronger, making fluoride beneficial to everyone (B). **Although it is true that multiple exposures to fluorides are now available through food sources as well as dentifrices, rinses, and other products, the addition of fluoride to the community water supply still significantly reduces the caries incidence in the population, saves considerably more in treatment costs than the cost of implementing fluoridation, is more cost effective than any other method of caries control, and has social equity (D).

25. A 5-year-old child presents to the dental office in a community in which the water is not fluoridated and the natural level of fluoride in the water is 0.2 ppm. Which of the following daily dosages of sodium fluoride (NaF) supplement tablets should be prescribed for this child? A No supplement B 0.25 mg NaF C 0.50 mg NaF D 1.0 mg NaF

ANS: C For children age 3 to 6 years, 0.50 mg NaF is recommended if the community water supply contains 0.3 ppm or less fluoride (C) **0.25 mg is recommended if it contains 0.3 to 0.6 ppm fluoride (B) **and no supplementation (A) is recommended if it contains more than 0.6 ppm. **1.0 mg/day (D) would only be given in ages 6 to 16 for a water supply of less than 0.3 ppm. **The ADA has recommended the dosage for fluoride supplements based on the age of the child and the amount of fluoride in the water. Use of supplements above the recommended dose may cause fluorosis. The ADA recommendations are listed below.

5. Which of the following over-the-counter mouthrinses has been accepted by the ADA and approved by the FDA to control and treat plaque biofilm and gingivitis? A Chlorine dioxide B Chlorhexidine gluconate (Peridex) C Essential oils (Listerine and generic versions) D Cetylpridinium chloride (CPC), Crest Pro-Health, Scope

ANS: C Listerine and its generic versions (C) are the only ADA-accepted, over-the-counter mouth rinses used to treat plaque biofilm, gingivitis, and volatile sulfur compounds producing organisms that cause malodor. **Chlorine dioxide (A) is an oxygenating agent found in mouth rinses such as Oxygene, Clo-Syst II. These agents do not have ADA or FDA endorsement, and long-term studies have not shown their beneficial effects on plaque or gingivitis reduction. **Chlorhexidine gluconate (Peridex) (B) also has ADA acceptance and FDA approval for treatment of gingivitis but is only available by prescription. **Quarternary ammonium compounds such as Cetylpridinium chloride (CPC), the active ingredient in Crest ProHealth (D) have been shown to be effective against plaque and gingivitis but do not have ADA or FDA endorsement for reducing the volatile sulfur compounds linked to oral malodors.

60. Negative outcomes for failure to remove or smooth an overhanging restoration include all the following EXCEPT one. Which one is the EXCEPTION? A Bony defects B Tissue irritation C Occlusal trauma D Food entrapment

ANS: C Overhanging restorations cause interproximal problems that do not include occlusal trauma (C). **Removal of an overhanging restoration is recommended because it can cause negative outcomes such as bony defects (A), tissue irritation (B), and food and plaque entrapment (D), which in turn contributes to periodontal disease advancement.

10. Which of the following actions should be performed before the placement of dental sealants? A Application of fluoride B Dental prophylaxis C Caries risk assessment D Oral hygiene instruction

ANS: C Risk assessment (C) is the first approach in prevention. By identifying the risk factors, preventive recommendations can be individualized to the patient's needs. **Fluoride treatment (A) is recommended after sealant application to remineralize enamel surfaces etched during sealant preparation. **Dental prophylaxis (B) is not necessary before placement of dental sealants, although the surfaces should be cleaned in preparation for sealant application. **Oral hygiene instruction (D) is part of comprehensive dental hygiene treatment but does not necessarily have to be done before pit and fissure placement.

53. Dental sealants may be filled or unfilled resins or glass ionomers that contain fluoride. Glass ionomer sealants are the sealant of choice for occlusal surfaces. A Both statements are true. B Both statements are false. C The first statement is true, and the second statement is false. D The first statement is false, and the second statement is true.

ANS: C The first statement is true, and the second statement is false (C). Both filled and unfilled resins and glass ionomers may be used for dental sealants. The second statement is false. Glass ionomer materials are susceptible to wear and loss and are not the best choice for the high rates of wear that occur on occlusal surfaces, even though they contain slow-release fluoride, which enhances the caries resistance of the tooth. **Choices A, B, and D do not accurately reflect the statements.

32. One suitable option for an antiplaque mouth rinse recommendation is chlorhexidine. Chlorhexidine is readily available as an over-the-counter medication. A Both statements are true. B Both statements are false. C The first statement is true, and the second statement is false. D The first statement is false, and the second statement is true.

ANS: C The first statement is true, and the second statement is false (C). Chlorhexidine is used as an antimicrobial agent to destroy bacterial cell membranes; controlling microbial levels in patients at high risk for caries or periodontal disease. It is recommended as a prescription antiplaque agent (not available over-the-counter) for high-risk patients because it inhibits bacterial colonization and prevents pellicle formation. Its substantivity promotes bacterial suppression for several hours at a time. **Choices A, B, and D do not accurately reflect the statements.

7. Chlorhexidine has been shown to be effective as an antimicrobial to control dental caries in patients who are at high risk for caries. The recommended protocol is the same as that used to control gingivitis. A Both statements are true. B Both statements are false. C The first statement is true, and the second statement is false. D The first statement is false, and the second statement is true.

ANS: C The first statement is true, and the second statement is false (C). Chlorhexidine is used in two ways to treat dental caries. Professionally, it is used as a cavity cleanser during restorative treatment. It is also prescribed as a self-administered oral rinse of 0.12% chlorhexidine gluconate. The protocol for the rinse for control of gingivitis is to rinse twice a day for 30 seconds with 15 milliliters (mL) of chlorhexidine for up to 6 months. In contrast, the protocol for prevention of dental caries is to rinse once a day with 15 mL for 1 minute for 1 week of each month until the bacterial load is reduced, as measured by a salivary bacterial culture. **Choices A, B, and D do not accurately reflect the statements.

23. There are greater caries reduction benefits from combining several methods of self-administered topical fluoride products with water fluoridation rather than one method alone. Combining several methods of topical fluorides and water fluoridation will cause fluorosis in the adult patient. A Both statements are true. B Both statements are false. C The first statement is true, and the second statement is false. D The first statement is false, and the second statement is true.

ANS: C The first statement is true, and the second statement is false (C). Fluoride has a dose-response relationship, so exposure to multiple sources of fluoride, especially in lower concentrations administered daily, increases the caries reduction benefits. High-risk patients will benefit from the combination topical fluoride products to the consumption of fluoridated water. The second statement is false. Fluorosis occurs only when fluoride is ingested in excessive amounts during the late secretion to early maturation stage of enamel formation in the course of tooth development. Once tooth development is complete, any amount of topical fluoride exposures, whether in combination with water fluoridation or not, is not a risk factor for fluorosis. Swallowing of topical fluoride products regularly by young children during tooth development has the potential to cause fluorosis, so children should be supervised when using topical fluoride products. **Choices A, B, and D do not accurately reflect the statements.

40. Modern sealant products polymerize or "cure" through use of a blue light source. The disadvantage of using a light-cured system is that clinicians may experience wrist fatigue if necessary precautions are not utilized. A Both statements are true. B Both statements are false. C The first statement is true, and the second statement is false. D The first statement is false, and the second statement is true.

ANS: C The first statement is true, and the second statement is false (C). Light-curing or light activation of sealant material is the most commonly used curing method today. The light source emits a white light through a blue filter, which reacts with a specific catalyst within the resin to produce the polymerization reaction. Long-term consequences of optical discomfort can be avoided by utilizing a protective dark yellow/orange shield, either on the light source or as protective operator eyewear. The weight of the curing light is not heavy enough nor is it manipulated long enough to cause wrist fatigue to the clinician. **Choices A, B, and D do not accurately reflect the statements.

47. When fluoride reacts with stomach acid, the reaction product is hydrogen fluoride. The initial symptoms of chronic fluoride toxicity are nausea, gastrointestinal pain, and vomiting. A Both statements are true. B Both statements are false. C The first statement is true, and the second statement is false. D The first statement is false, and the second statement is true.

ANS: C The first statement is true, and the second statement is false (C). When fluoride is swallowed, it reacts with acids present in the stomach; the reaction product is hydrogen fluoride, and this is considered acute fluoride toxicity, which produces initial symptoms of nausea, gastrointestinal pain, and vomiting. Chronic fluoride toxicity, on the other hand, occurs over a length of time when the enamel is forming and leads to Hypomineralization of the enamel, or dental fluorosis. **Choices A, B, and D do not accurately reflect the statements.

61. Communication can be considered a preventive agent when a dental professional identifies harmful habits and encourages changes in patient behavior; therefore, the dental professional should avoid discussing a patient's recreational drug use. A Both the statement and the reason are correct and related. B Both the statement and the reason are correct but NOT related. C The statement is correct, but the reason is not. D The statement is NOT correct, but the reason is correct. E NEITHER the statement NOR the reason is correct.

ANS: C The statement is correct, but the reason is not (C). Communication can be considered a preventive agent when a dental professional identifies harmful habits and encourages changes in patient behavior; therefore, the dental professional should discuss all conditions and observations, including drug use, related to the patient and behaviors. **Choices A, B, D, and E do not accurately define the statement.

59. Which of the following is a best practice for the use of an oral irrigator? A Flush gingival sulcular areas directly. B Gradually increase the intensity of the stream to high. C Direct the stream perpendicular to the long axis of the tooth. D Use in limited access areas without soft-tissue inflammation.

ANS: C When an oral irrigator is being used, the stream of water should be directed perpendicular to the long axis of the tooth (C), just above the interproximal papilla. **The irrigating stream should not be aimed directly into the gingival sulculus (A). **The stream intensity should remain on low (B). **The irrigator is useful in limited access areas with soft-tissue inflammation present (D

30. Your patient has just concluded orthodontics therapy and is upset about the white areas in the former location of the brackets. Which of the following would be the BEST dentifrice recommendation for this patient? A Anti caries dentifrice with fluoride B Antiplaque dentifrice with triclosan C Whitening dentifrice to even out enamel coloration D Remineralization dentifrice with fluoride and calcium phosphate

ANS: D A re-mineralizing dentifrice with fluoride and calcium phosphate (D) will promote reversal of incipient carious or "white spot lesions" by enhancing the uptake of fluoride and minerals into the enamel surface. White spot demineralized lesions often result from orthodontic therapy because of compromised oral hygiene during treatment. The re-mineralized area is a harder, stronger fluorapatite crystalline structure within enamel that can better withstand bacterial acid attacks. **An anti-caries dentifrice with fluoride (A) is beneficial but is not as effective as a dentifrice specifically formulated for remineralization. **The effectiveness of triclosan (B) is in relation to control of inflammation and gingivitis, not dental caries. **A whitening dentifrice to even out enamel coloration (C) would not effectively treat the white spot lesions.

52. The dental hygienist has finished placing a pit and fissure sealant and discovers a bubble in the cured sealant material. Which of the following actions is MOST appropriate? A Using a high-speed hand piece and smooth the surface B Adding more sealant material and polymerizing the area C Leaving the bubble; mastication will remove the imperfection D Re-etching, washing and drying the tooth, and applying additional material

ANS: D Air bubbles leave a void and do not provide effective caries prevention. The best action is to re-etch the tooth (D) so that the surface feels hard and smooth and firmly bonded to the tooth. Air bubbles should not be present. **Smoothing the area (A) could expose the void and leave an unprotected enamel surface, and adding more sealant material (B) could interfere with occlusion. **Leaving the bubble and expecting mastication to fix the problem (C) is not a good solution, since most sealants today are filled and are resistant to occlusal wear.

71. Education for a patient who wears an obturator should include all the following teaching points EXCEPT one. Which one is the EXCEPTION? A Food takes longer to clear the oral cavity. B Soft-food consumption increases caries risk. C Tenacious nature of nasal fluids promotes biofilm retention. D Systemic fluorides are contraindicated due to risk of choking.

ANS: D Due to the increased risk of caries development, topical and systemic fluorides (D), along with dental sealants and use of therapeutic doses of xylitol-containing products are indicated. **Caregivers and patients who wear obturators to cover palatal defects should be educated about the longer time needed to clear the mouth of foods (A), the relationships between soft-food consumption (B) and biofilm retention, and the tenacious nature of nasal fluids (C) with an increased risk of caries development.

65. Characteristics of patient-centered tobacco cessation communication include all the following EXCEPT one. Which one is the EXCEPTION? A Listening B Collaboration C Eliciting of information D Emphasis on expert authority

ANS: D Emphasis on the patient's autonomy, rather than the expert authority (D), places the responsibility for change on the patient. **Characteristics of patient-centered communication includes listening (A), collaboration (B) that honors the patient's experience and perspectives, and the drawing out or eliciting of information (C) to learn about the patient's beliefs, values, and motivation levels.

2. Which of the following fluoride compounds is NOT used in professionally administered fluoride products to prevent dental caries? A Sodium fluoride (NaF) B Stannous fluoride (SnF2) C Acidulated phosphate fluoride (APF) D Sodium monofluorophosphate (MFP)

ANS: D MFP (D) is NOT used in professionally administered fluoride products to prevent dental caries, although it is found in many widely used dentifrices. **NaF (A), or neutral fluoride, is preferred for professional applications for patients with mucositis, sensitivity, and esthetic restorations. NaF is the active agent in professionally applied fluoride varnish. **SnF2 (B) is available in professionally dispensed gels for dentinal hypersensitivity and as professional rinses, although the rinses have largely been replaced by other professional fluorides. **APF (C) provides the greatest uptake when used for professional topical fluoride gel and foam applications because of the low pH.

45. Which of the following concentrations of neutral sodium fluoride is considered a professionally applied fluoride (in-office administration) agent? A 0.1% B 0.5% C 0.2% D 2.0%

ANS: D Neutral sodium fluoride 2.0% (D) gel or foam is a professionally applied agent available by prescription and used twice annually or as caries incidence requires. **Neutral sodium fluoride 0.1% (A) is used in over-the-counter dentifrices twice daily, whereas NSF 0.5% (B) is used in over-the-counter rinses twice daily. NSF 0.2% (C) is used once a week in rinses, also available over-the-counter.

63. Which of the following preventive measures is recommended for a patient taking medication to lower blood pressure? A Use iodized salt. B Limit fatty food. C Add zinc supplements. D Restrict sodium intake.

ANS: D Restriction of dietary sodium intake (D) is effective in lowering the mean blood pressure. **Although iodine is necessary for metabolic needs, the use of iodized or plain salt (A) should be restricted in individuals with high blood pressure. **Consumption of fatty foods (B) is a concern for patients with high cholesterol (HDL). **Zinc supplements (C) can adversely affect HDL levels and should not be advocated for indiscriminate use.

20. Which of the following is the MOST commonly used fluoride compound in water fluoridation? A Sodium fluoride B Stannous fluoride C Hydrofluosilicic acid D Sodium silicofluoride

ANS: D Sodium silicofluoride (D) is the most commonly used compound in community water fluoridation, and the least expensive because it is a byproduct of fertilizer production. **Three fluoride compounds are used for water fluoridation: sodium fluoride (A), sodium silicofluoride (D), and Hydrofluosilicic acid (C). The type of fluoride selected by a community is determined by the type of equipment used for fluoridation, which is dependent on the size of the community (the volume of water being treated). **Stannous fluoride (B) is used in professionally applied topical gels, foams, and solutions, not in community water fluoridation.

41. Which of the following BEST describes the purpose for the use of a sealant material with fluoride added? A It increases the long-term retention of the sealant. B It adds to the resistance against wear and abrasion. C It acts as a long-term reservoir for fluoride in the oral cavity. D It inhibits caries growth in the enamel surrounding the sealant.

ANS: D Studies currently demonstrate evidence of fluoride release into the surrounding enamel as a means of inhibiting caries growth (D). **Although research has shown that fluoride-incorporated sealants have high retention rates up to 48 months following placement, after that, their long-term retention decreases dramatically, failing to add to the overall retention (A). **Sealants with fluoride added do not have any additional resistance against wear and abrasion (B). **Adding fluoride to the sealant material has not been shown to serve as a reservoir for continuous fluoride uptake and release into the oral cavity (C).

43. Which of the following represents the ADA's recommendation for maintaining a dry field during sealant placement? A Use of cotton rolls B Use absorbent pads C Use of a rubber dam D Use of two operators

ANS: D The ADA recommends the use of two operators to maintain a dry field during sealant placement, allowing one clinician to focus on moisture control (D). **Cotton rolls (A) and absorbent pads (B) are effective during sealant placement, but the presence of a second operator is more effective. **A rubber dam (C) is very effective in isolating and maintaining a dry area; however, many dental hygienists prefer not to use this technique because of the extra time involved in placement and the potential for patient discomfort.

27. All of the following statements are true EXCEPT one. Which one is the EXCEPTION? A Fluorosis can be controlled in the population by controlling the risk factors. B The trend in the United States is an increase in the prevalence of slight fluorosis in children. C The new CDC recommendation to reduce fluoride levels in water supplies indicates that some public health care professionals consider the level of fluorosis to be a public health problem. D The rate of fluorosis is continuing to increase because of the high level of fluoride in children's toothpaste.

ANS: D The concern about increasing fluorosis has led to the recent development of children's dentifrices with lower or no fluoride, not high levels (D). **Fluorosis can be controlled in the population by controlling the risk factors (A) such as fluoride ingestion during the development stage of enamel formation. This begins as early as 22 months for the maxillary central incisors when children cannot control swallowing during tooth brushing and continues for several years until enamel has formed on all permanent teeth. **The trend over the last few decades has been an increase in fluorosis, especially in the very mild to mild categories, primarily because of children inadvertently swallowing fluoride dentifrices (B). **The new CDC recommendation to lower the optimal level of fluoride in community water supplies to 0.7 ppm for all geographic areas of the United States is in response to health care professionals' concern that higher rates of fluorosis have become a public health problem (C).

56. Fluoride is added to the surface of enamel before tooth eruption. The uptake of fluoride depends on the level of fluoride in the oral environment and the length of time of exposure. A Both statements are true. B Both statements are false. C The first statement is true, and the second statement is false. D The first statement is false, and the second statement is true.

ANS: D The first statement is false, and the second statement is true (D). Fluoride is added to the surface of the enamel after tooth eruption. The second statement is true. The uptake of fluoride depends on the level of fluoride in the oral environment and the length of time of exposure. **Choices A, B, and C do not accurately reflect the statements.

16. Fluoride supplements are recommended by the FDA because research has shown them to be safe to the developing fetus. Research has demonstrated that fetal plasma fluoride levels increase as a result of prenatal fluoride supplementation, but the benefit of prenatal fluoride to the child is minimal. A Both statements are true. B Both statements are false. C The first statement is true, and the second statement is false. D The first statement is false, and the second statement is true.

ANS: D The first statement is false, and the second statement is true (D). The FDA does not recommend fluoride supplements because the benefit to the developing fetus is minimal, not because of any safety concerns. This is because enamel formation of permanent teeth occurs after birth and the primary benefits of fluoride occur after teeth erupt following birth. There are no ill effects of optimal fluoride consumption by the mother on the development of the fetus.

15. Ingested fluoride is excreted primarily through saliva. Excretion of fluoride through saliva is the reason that water fluoridation has post eruptive caries reduction benefits in both children and adults. A Both statements are true. B Both statements are false. C The first statement is true, and the second statement is false. D The first statement is false, and the second statement is true.

ANS: D The first statement is false, and the second statement is true (D). The primary excretion of excess fluoride is in urine, not saliva. Saliva is a secondary means by which fluoride is excreted, providing topical benefits. The second statement is true. When fluoride is consumed regularly through water, food, supplements, or all of these, saliva provides continual intraoral bioavailability of fluoride for enhanced remineralization, prevention of demineralization, and an antimicrobial effect. **Choices A, B, and C do not correctly reflect the statements.

50. Topically applied fluorides are most effective for prevention of dental caries formation in the pits and fissures of teeth. Dental sealants should be the primary preventive consideration by the dental hygienist for reduction in pit and fissure caries of teeth. A Both statements are true. B Both statements are false. C The first statement is true, and the second statement is false. D The first statement is false, and the second statement is true.

ANS: D The first statement is false, and the second statement is true (D). Topically applied fluorides are most effective for preventing dental caries formation on the smooth surfaces of teeth and least effective in pits and fissures. The second statement is true. Dental sealants are highly effective in reducing caries in the pits and fissures of teeth and should be a primary preventive consideration for dental hygienists. **Choices A, B, and C do not accurately reflect the statements.

66. Use of a properly fitted mouth guard while an individual plays sports helps to protect against all the following conditions EXCEPT one. Which one is the EXCEPTION? A Bruxism B Clenching C Head injuries D Mouth breathing

ANS: D Use of a properly fitted mouth guard while an individual is playing sports is not designed to prevent mouth breathing (D). **A properly fitted mouth guard can prevent bruxism (A), clenching (B), and head injuries (C).

14. Fluoride is stored in the body in which of the following two locations? A Blood B Liver C Saliva D Teeth E Bones

ANS: D, E Excess fluoride is stored in the hard tissues of bones and the developing enamel of teeth (D, E). **Ingested fluoride is absorbed from the acid pH environment of the stomach and upper intestine by blood (A) and is carried in blood plasma throughout the body as ionic fluoride. **The liver (B) does not store fluoride. **Excess fluoride is excreted rapidly primarily in urine but also in saliva. Saliva serves as a temporary reservoir of fluoride for continual topical benefit (C). The kidneys are responsible for excreting excess fluoride, so kidney health is important to maintain the fluoride balance in the body. Patients on kidney dialysis must use mineral free water that has been treated with reverse osmosis to remove fluoride and other chemicals.