2025 Edition

NBDHE Dental Hygienist Practice Test

Take this FREE NBDHE sample practice test below to see how prepared you are for a dental hygienist certification exam.

The NBDHE Dental Hygienist exam has 350 questions and has two components - Discipline Based and Dental Hygiene Patient Cases. The first component covers these main exam sections: Scientific Basis for Dental Hygiene Practice; Provision of Clinical Dental Hygiene Services and Principles of Community Health and Research. The second component of patient cases contains at least one each of geriatric, periodontal, pediatric, special needs and medically compromised patient cases.

For complete practice, check out the NBDHE Practice Exam Kit with 750 questions and fully explained answers, including 20 Patient Case Testlets.

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1.	Hypersensitivity of a root lessens as the tooth forms which of the following?
		a. Periodontal Ligament
		b. Pulp
		c. Cellular cementum
		d. Enamel
Cementum is the thin, hard dentinal tissue layer that covers the roots of a tooth. Cellular cementum is associated with the apical half of the root that extends onto the inner wall of the pulp canal; the pulp supplies the nerve endings of the tooth. The cellular cementum must form to reduce the hypersensitivity of a root. Another plausible answer is enamel, as enamel is the hard outer layer covering the crown of the tooth. However, the keyword here is root: Enamel protects the crown of the tooth, whereas cellular cementum protects the root. The periodontal ligament does not serve to protect at all; its purpose is for attachment. It is the tissue between the tooth and the bone that holds the tooth in place. Incorrect answer. Please choose another answer.

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2.	What nerve supplies the intrinsic muscles of the tongue?
		a. Trochlear
		b. Trigeminal
		c. Glossopharyngeal
		d. Hypoglossal
		e. Accessory
All intrinsic muscles of the tongue are innervated by the Hypoglossal (CN XII) Nerve. “Glossal” is derived from the Latin word for tongue “glossa,” so this derivative can be used to remember that words associated with the tongue will have “glossal” in them. Glossopharyngeal also relates to the tongue, but is the nerve that regulates swallowing, as glossopharyngeal refers to both the mouth and the throat (pharyngeal/pharynx) along with the tongue. The Trochlear nerve is one of the cranial nerves that functions to control eye movement. The Trigeminal nerve is the nerve most commonly talked about in dentistry as it is the nerve that is responsible for transmitting sensory, motor, and other stimuli to the head and neck, but it does not supply the intrinsic muscles of the tongue. Incorrect answer. Please choose another answer.

3.	Which of the following is the most radioresistant?
		a. Glands
		b. Reproductive organs
		c. Bone Marrow
		d. Skin
		e. Nerves
Neurons are non-proliferating cells. Non-proliferating cells are more resistant to radiation than proliferating cells. Glands, reproductive organs, bone marrow, and skin all have proliferating cells, making these structures all radiosensitive. Incorrect answer. Please choose another answer.

4.	Fluoride is typically introduced in all of the following ways except by:
		a. Drinking water
		b. Vitamins
		c. Injection
		d. Toothpaste
		e. Mouthwash
Fluoride is not available as an injectable supplement. Fluoride is commonly found in toothpaste and mouthwash, as well as ingestible vitamins for children. Another plausible answer may have been drinking water as fluoride is not in all available water, such as well water, but fluoride was added into most drinking water as a Public Health Service in 1945. Incorrect answer. Please choose another answer.

5.	Gingivitas is considered controlled when:
		a. the gums reach the crown.
		b. no deep pockets appear in the gums
		c. the gums appear firm
		d. the plaque has been removed
		e. there's no bleeding around the gums
Bleeding is the number one sign of gingivitis, as it occurs as an immune response due to localized irritants around the gums (plaque, food debris, etc.) Receding gums and deep pocketing may be a sign of gingivitis but in the context of this question, it are not the correct answer. A patient may have gums that do not reach the crown of the tooth but are healthy and stable. Once the gingiva starts to recede, it will not come back to its original position along the crown. Also, a deep pocket is usually a sign of gingivitis/periodontitis, but it can occur without either condition, such as when a tooth has a fracture in one of its roots. The gums may be completely healthy otherwise, but a clinician may record a localized 8-9mm pocket if a root fracture is present. Incorrect answer. Please choose another answer.

6.	A flat stone may be used to sharpen a curette by hand. The face of the curette should be at what angle to the stone?
		a. 50-65 degrees
		b. 75-85 degrees
		c. 90-100 degrees
		d. 100-110 degrees
		e. 125-135 degrees
The face of the curette should be at a 100-110 degree angle to properly access the cutting edge of the curette. Insufficient angulation can alter the contour of the curette which can cause the instrument to weaken and dull quickly and potentially become unsafe for scaling. Incorrect answer. Please choose another answer.

7.	Radiographic intensifying screens are used for:
		a. magnification
		b. sharpening the image
		c. reducing the patient dose
		d. reflecting harmful rays
		e. expediting the processing time
Intensifying screens use light to produce photons needed for the x-ray. This reduces mAs needed to produce a specific density. They also reduce blur and exposure time, all of which reduces patient dose significantly, as it minimizes the potential for retakes. Incorrect answer. Please choose another answer.

8.	After an outbreak of herpetic gingivostomatitis, the herpes simplex virus may remain dormant in which of the following?
		a. Sensory ganglion
		b. Salivary Glands
		c. Blood
		d. Ligaments
		e. Lymph nodes
Herpetic gingivostomatitis (also known as “cold sores”) is an infection caused by the herpes simplex virus (specifically type 1 or HSV-1). Neurons in the sacral ganglia are the site of all types of herpes simplex virus latency. Incorrect answer. Please choose another answer.

9.	Which of the following is the most significant characteristic of an overdenture?
		a. No natural teeth remain
		b. Natural teeth remain
		c. Used with an overbite
		d. Used with an underbite
A denture is a dental prosthesis used to replace missing teeth and restore a patient's dentition. A full denture is a removable dental prosthesis used when no natural teeth remain. An overdenture is a dental prosthesis that is attached to remaining natural teeth or dental implants, that is typically fixed or permanent. It could be used with an overbite or underbite and therefore could be a characteristic of an overdenture, however it is not ideal as this is not the preferred occlusion, and ideally corrected prior to needing any dental prosthesis. While these characteristics are not wrong, they are not the most significant. The main feature/characteristic of an overdenture is that in can be placed in conjunction with remaining natural teeth. Incorrect answer. Please choose another answer.

10.	A dental carie is another name for:
		a. a dental instrument
		b. the gum line
		c. a cavity
		d. Plaque build-up
		e. Gingivitis
Dental caries is the dental terminology used to describe tooth decay, also known as a cavity. The term originates from the Latin word for decay, which is “caries.” Incorrect answer. Please choose another answer.

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11.	Which of the following is one of the main reasons for a root canal?
		a. The tooth is cracked
		b. The pulp can't be fixed
		c. Gums are bleeding
		d. A cavity is present
		e. Enamel is worn off
A root canal is needed when the pulp within a tooth becomes infected with deep decay, or when the pulp cannot be fixed. Other plausible answers are when the tooth is cracked and when a cavity is present. It is true that a cavity is likely present, but the key concept here is that the cavity needs to be deep within the pulp in order for a root canal to be indicated. Also, a crack or fracture in the tooth may indicate the need for a root canal, but again, a root canal is the indicated treatment if the crack is deep enough into the crown of the tooth where it permeates into the pulp and cannot be treated with a simple restoration or crown. Incorrect answer. Please choose another answer.

12.	Vital whitening is performed on which of the following?
		a. Dentures
		b. Tooth with no live nerve
		c. Tooth with live nerve
		d. Cavities
		e. Tooth roots
The keyword here is “vital;” a vital tooth is a live tooth, or a tooth with a live nerve. It is important to note that a patient should not whiten a tooth with a cavity as the bleaching component in a whitening solution can cause more damage to the already demineralized carious lesion. Incorrect answer. Please choose another answer.

13.	A vasoconstrictor does which of the following when used in conjunction with Lidocaine?
		a. Helps the drug get into the blood stream
		b. Helps the numbing drug work
		c. Helps the drug resist breaking down
		d. Makes the numbness wear off
		e. Makes the numbness last longer
Local anesthetics are used to numb a localized area before a procedure to ensure patient comfortability. Local anesthetics cause dilation of blood vessels in the surrounding area which causes the anesthetic to be absorbed or spread quickly into the bloodstream. The use of a vasoconstrictor constricts the blood vessels which keeps the anesthetic in the localized area for a longer period of time, hence making the numbness last longer. It does not help the drug resist breaking down; breaking down would be incorrect terminology here. It stops absorption of the drug into the bloodstream. A vasoconstrictor does help the drug get into the bloodstream and help the numbing drug work (choices a and b), however the two main purposes of a vasoconstrictor are to help reduce bleeding and to prolong the duration of the anesthetic. It prolongs the duration of the anesthetic by delaying absorption into the bloodstream. Bleeding reduction is not a listed choice, so the best answer here would be choice e. Incorrect answer. Please choose another answer.

14.	When a periapical abscess forms, it indicates what?
		a. The gums are infected
		b. Tooth enamel is worn thin
		c. A cavity
		d. A dead or dying tooth root
		e. Plaque build-up
An abscess indicates the presence of infection. A periapical abscess refers to the infection in the root of a tooth. A root canal is the indicated treatment once the root is infected, or dead/dying. Gum infections do not lead to a periapical abscess. An individual can present with gingivitis or even periodontitis and never experience a periapical abscess as a gum infection is typically superficial. Thinning of tooth enamel will not lead to a periapical abscess. Teeth are constantly experiencing wear and tear and may slowly break down or thin over time. This can lead to sensitivity issues, but likely will not lead to an abscess. Answer C is a plausible choice as a cavity could lead to an abscess if it becomes so deep it reaches the pulp/the roots, but this is not the best answer as a simple cavity can be restored and will not lead to a periapical abscess. Plaque build-up can lead to gum irritation or even a gum infection, but as stated before, it is unlikely to cause an abscess. If a periapical abscess is formed, it indicates that something significant is going on with the root of the tooth. For any periapical condition, think “root”. Incorrect answer. Please choose another answer.

15.	If a dentist is placing a bonded filling, she will do which of the following to ensure the filling bonds to the tooth?
		a. X-ray the tooth
		b. Scrape the tooth
		c. Polish the tooth
		d. Etch the tooth
		e. Drill the tooth
The process of etching a tooth needs to be completed in order for the material of the bonded filling to adhere to the enamel. Etch is composed of an acid gel that demineralizes and roughens the enamel so that the filling material can bond to the tooth. All of the answers listed above are steps in the procedure of filling or restoring a tooth, but when referring to the process of bonding specifically, etching the tooth is the specific step necessary to ensure the filling bonds to the tooth. Incorrect answer. Please choose another answer.

16.	A pedicle graft uses a flap of tissue from which part of the mouth?
		a. From a neighboring tooth
		b. From the roof of the mouth
		c. From the inside cheek
		d. From any location it can be found
		e. From the bottom of the mouth
A pedicle graft utilizes the tissue from the gingiva surrounding the tooth indicating the need for a graft, as the cells and composition of the tissue are the same, providing optimal success of adherence of the graft. This type of grafting is preferred for small areas needing grafting, as it doesn't cut off blood flow and has a high success rate. Another plausible answer as it is the most common method, is obtaining tissue from the roof of the mouth. This is called a free gingival graft however, and is used for larger areas needing grafting and extra support, such as the entire row of mandibular anteriors rather than one individual tooth where a pedicle graft can be utilized. Incorrect answer. Please choose another answer.

17.	Where does the bone for a bone augmentation typically come from in an implantation procedure?
		a. Tibia
		b. Radius
		c. Chin or Ramus
		d. Hip
		e. Humerus
Similarly to pedicle grafting, bone augmentation for implantation procedures comes from the chin or ramus as the cells in the bone are the same and are more likely to accept the implant following surgery. Another plausible answer would be the hip, as bone for other bone grafts of the body typically come from the iliac crest, or hip area. For dental bone grafts, the bone will be taken from the chin or jaw however. Incorrect answer. Please choose another answer.

18.	A veneer will correct all of the following except:
		a. Slightly crooked teeth
		b. A tooth with a cavity
		c. Chipped teeth
		d. Gaps between teeth
		e. Teeth with different lengths
Veneers are similar to crowns (also known as caps) in that they are shells attached to teeth typically treatment planned for cosmetic purposes on anterior teeth, specifically maxillary anterior teeth. Veneers are a great solution to improve slightly crooked teeth, chipped teeth, to make teeth of different lengths uniform, and can even assist with closing gaps between teeth. If the tooth treatment planned for a veneer has an existing cavity, the cavity would be treated prior to the veneer being placed. Incorrect answer. Please choose another answer.

19.	Patients should give informed consent to all dental procedures. Which of the following is not a part of informed consent?
		a. Informing patients of the risks of treatment
		b. Patient's agreement to care
		c. Having a discussion of the treatment options with the patient
		d. Getting the patient's or guardian's signature
		e. Obtaining a dental history of the patient
Obtaining a dental history of the patient is the very first step of all dental appointments but is not a step in the process of informed consent. Informed consent involves complete comprehensive discussion of the treatment the patient will be receiving and their consent to proceed with it. Incorrect answer. Please choose another answer.

20.	Which nerve is the most significant to dentistry?
		a. The abducent nerve
		b. The hypoglossal nerve
		c. The facial nerve
		d. The trigeminal nerve
The trigeminal nerve is the most significant nerve in dentistry, because it is the nerve that supplies all nerve innervation to the face and the mouth. This is the main nerve associated with injury, infection, and pain that a dentist or dental professional would need to take into consideration when planning dental procedures. Incorrect answer. Please choose another answer.

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21.	The following are all regions of the face, except:
		a. Mental region
		b. Labial region
		c. Zygomatic Region
		d. Infraorbital Region
There are 8 regions of the face which include the orbital region, infraorbital region, nasal region, zygomatic region, buccal region, parotid region, oral region, and mental region. The word "labial" refers to the lips, but the oral region is the region used when referencing the mouth. Incorrect answer. Please choose another answer.

22.	Where might you find the majority of the papillae on the tongue?
		a. The ventral surface of the tongue
		b. The lateral surface of the tongue
		c. The dorsal surface of the tongue
While there are papillae on the ventral and lateral surfaces of the tongue, the majority are found on the dorsal surface. Foliate papillae are found on the lateral surfaces of the tongue. Lingual papillae are found on the ventral surface of the tongue. Four different types of papillae are found on the dorsal surface: filiform, fungiform, foliate, and circumvallate papillae. Incorrect answer. Please choose another answer.

23.	Which of the following are muscles of mastication?
		a. Masseter
		b. Lateral Pterygoid
		c. Medial Pterygoid
		d. Temporalis
		e. All of the above
The muscles of mastication include all of the muscles listed above. It is commonly thought that the buccinator muscle is one of the muscles for mastication. However, the buccinator is considered to be one of the assistant muscles of mastication, not one of the four main muscles. Incorrect answer. Please choose another answer.

24.	Which specialty of dentistry is the Palmer Notation Method most commonly used in?
		a. Orthodontics
		b. Periodontics
		c. Endodontics
		d. Oral Surgery
The Palmer Notation Method is most commonly used in orthodontics, where it is used to label and identify both primary teeth and adult teeth using a symbol to designate quadrants. All other dental specialties (periodontics, endodontics, and oral surgery) utilize the Universal Numbering System in the U.S. The FDI Numbering System is the numbering method used in other countries outside of the U.S. Incorrect answer. Please choose another answer.

25.	What is the term for when the maxillary arch horizontally overlaps the mandibular arch by 1-3 mm?
		a. Overbite
		b. Overjet
		c. Underbite
		d. Crossbite
Overjet is the term used for when the maxillary arch horizontally overlaps the mandibular arch by about 1-3mm. Another plausible answer and another type of overlap would be overbite, but overbite is the term used for when the maxillary arch vertically overlaps the mandibular arch by about 1-3mm. Underbite is the term used for when the mandibular arch vertically overlaps the maxillary arch by 1-3mm. Crossbite is the term used for when there is a misalignment in the occlusion (or the bite) and the maxillary teeth close together distally (or behind) the mandibular teeth. The maxillary teeth should place facially to the mandibular teeth in ideal occlusion (Class I Occlusion). Incorrect answer. Please choose another answer.

26.	Which of the following parafunctional habits affect malocclusion of the jaws?
		a. Clenching
		b. Tongue thrust
		c. Lip incompetence
		d. Abfraction
		e. All of the above
Parafunctional habits are repetitive habits that affect the formation of the dentition and other structures within the oral cavity. Clenching affects facial muscles, causing them to be overactive and enlarged, and also wears down the enamel on the teeth, causing wear facets and attrition. Tongue thrusting can result in an overjet and misalignment of teeth. Lip incompetence involves the inability to close one's lips together at rest, which causes lower facial strain and can lead to mouth breathing and dryness of the oral cavity. Abfraction causes loss of tooth structure which can overall affect the dentition, by forcing some teeth to compensate in alignment and in function for others. Incorrect answer. Please choose another answer.

27.	Hutchinson incisors and Mulberry molars are developmental disturbances caused by which
		a. Congenital heart disease
		b. Psoriasis
		c. Fetal alcohol syndrome
		d. Congenital syphilis
Syphilis may lead to a variety of symptoms and potential defects. Developmental disturbances occur while the fetus is developing. Congenital conditions and diseases are those that are present at birth. Another plausible answer may have been congenital heart disease or fetal alcohol syndrome as both of these affect the fetus and are present at birth. However, Hutchinson incisors and Mulberry molars occur due to defects in the formation of tooth cusps, which is caused by congenital syphilis. Incorrect answer. Please choose another answer.

28.	Something that deviates from what is standard or normal is called a(n):
		a. Anomaly
		b. Syndrome
		c. Disorder
		d. Atrophy
Anomalies deviate from the standard, the normal, or the expected. Another possible answer may have been a disorder, however a disorder is classified by a disruption. An anomaly typically is safe and benign, and has no overall effect on the individual (E.g. a birthmark or a supernumerary tooth/an extra tooth). A syndrome is an entire group of symptoms when all present together represent a certain condition or disease. Atrophy is the term used to describe a decrease or degeneration in tissue, whether it be muscular, glandular, etc. All of the other choices listed describe a disruption to the norm, where as an anomaly is a differentiation from the norm, but does not have any significant effects. Incorrect answer. Please choose another answer.

29.	The following are terms used to describe the clinical appearance of a soft tissue lesion, except:
		a. Macule
		b. Pedunculated
		c. Radiolucent
		d. Vesicle
Radiolucent is a term used to describe how a structure appears on a radiograph/x-ray. A radiolucent structure is almost completely transparent to radiation. The other descriptors describe lesions physically assessable on soft tissue such as the gingiva, for example. Incorrect answer. Please choose another answer.

30.	Which of the following immunologic diseases has the common characteristic of a "target" or "bull's eye" lesion?
		a. Sjögren Syndrome
		b. Systemic Lupus Erythematosus
		c. Pemphigus Vulgaris
		d. Erythema Multiforme
All of the conditions listed may produce some type of lesion on the skin. Erythema Multiforme produces bulls-eye-shaped lesions, specifically. Another plausible answer may have been Systemic Lupus Erythematosus, as it also refers to erythema (redness/inflammation) within the name of the disorder. With this condition however, a common characteristic is a butterfly rash spread across the cheeks and nose of the face. Incorrect answer. Please choose another answer.

31.	Which of the following infectious diseases is caused by coxsackievirus?
		a. Herpangina
		b. Hand-foot-and-mouth disease
		c. Measles
		d. Mumps
		e. All of the above
Coxsackievirus is an enterovirus that falls within a family of RNA viruses. All of the above infectious diseases are viral infections caused by the coxsackievirus. Incorrect answer. Please choose another answer.

32.	All of the following match the pneumonic for the ABCDEs of melanoma, except:
		a. A - Asymmetric
		b. B - Base
		c. C - Colors
		d. D - Diameters larger than 6 mm
		e. E - Evolving
The pneumonic for the ABCDEs of melanoma was created to be used as a memorable reference when evaluating lesions found on the skin for melanoma. The "B" in the ABCDEs is for "Borders," as the lesion's borders should be evaluated. An irregular border can be a sign that a lesion should be further evaluated or biopsied. Incorrect answer. Please choose another answer.

33.	Which of the following systemic diseases has a direct systemic link to periodontal disease?
		a. Grave's disease
		b. Addison's disease
		c. Celiac disease
		d. Diabetes mellitus
Diabetes is the only disease listed above with scientific literature proving a direct systemic link to periodontal disease. Scientists are currently evaluating the link between periodontal disease and CHF and periodontal disease and Alzheimer's, however, there is not enough literature at this time. Smoking has also been proven to have a direct link to periodontal disease. Incorrect answer. Please choose another answer.

34.	Which of the following medications has a side effect of dry mouth?
		a. Zoloft
		b. Adderall
		c. Risperdal
		d. Gabapentin
		e. All of the above
Dry mouth is a common side effect to many different types of medications. Common families of medications that may cause dry mouth include: anticholinergics, antidepressants (Zoloft), stimulants (Adderall), opioids, antipsychotics/mood disorder medications (Risperdal) and anticonvulsants (Gabapentin). Incorrect answer. Please choose another answer.

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35.	Scurvy is a clinical condition that results from which vitamin deficiency?
		a. Vitamin C
		b. Vitamin D
		c. Vitamin B
		d. Vitamin K
Scurvy results from a severe lack of Vitamin C. Oral manifestations of scurvy include swollen, bleeding gums that may become purple and spongy. Vitamin C is essential for tissue repair and healing wounds, such as bleeding gums. Incorrect answer. Please choose another answer.

36.	Oral thrush is a fungal infection in the mouth caused by:
		a. Streptococcus
		b. Candida albicans
		c. Treponema denticola
		d. Porphyromonas gingivalis
Oral thrush, also known as Oral candidiasis, is a fungal infection caused by the fungus Candida albicans. It causes white lesions throughout the oral cavity (specifically on the tongue, back of throat, and cheeks) and a cotton-like feeling in the mouth. All of the other choices are bacteria that can be found in the mouth. Streptococcus is commonly found in the normal flora of the mouth. Treponema denticola and Porphyromonas gingivalis are present in an individual who has periodontal disease. Incorrect answer. Please choose another answer.

37.	All of the following are oral manifestations of a patient who presents with bulimia, except:
		a. Enamel erosion
		b. Dental caries
		c. Hypersalivation
		d. Tooth sensitivity
		e. Parotid enlargement
Patients that present with bulimia tend to binge eat and then purge their food. The excessive acidity in the mouth due to consistent purging causes enamel erosion, which may lead to tooth sensitivity and potentially dental caries as well. The acidity causes dryness in the mouth so hypersalivation would not be an oral manifestation of bulimia. Incorrect answer. Please choose another answer.

38.	Which of the following requires a patient to premedicate prior to their dental appointment?
		a. A recent heart attack
		b. A recent surgery
		c. The start of a new medication
		d. Hip or knee replacement surgery
The protocol for a major joint surgery such as a hip or knee replacement requires a patient to take an antibiotic premedication prior to their dental appointment to protect against infective endocarditis. The length of time a patient needs to premedicate prior to a dental appointment depends on their surgeon. A surgeon may require a lifetime premedication protocol, or to premedicate for six months after the replacement surgery. The office/clinician should document clearance from the surgeon and have the surgeon's instructions for premedication on file for the patient. Another plausible answer may have been a recent surgery as some surgeries do require premedication such as a major joint surgery, however small/minor surgeries do not require any premedication. Incorrect answer. Please choose another answer.

39.	Complete tooth displacement from the socket following extensive trauma is called?
		a. Impaction
		b. Diastema
		c. Exfoliation
		d. Avulsion
When extensive trauma occurs to the mouth (such as from a car accident, being struck in the face with a ball, a frontwards fall, etc.), a tooth can become completely displaced from its socket. This is called avulsion. Exfoliation is the term used for the natural shedding of the teeth, such as when a child loses a baby tooth to make room for an adult tooth to erupt in its place. Incorrect answer. Please choose another answer.

40.	What is the primary cause of the condition known as Early Childhood Caries (ECC)?
		a. Delayed eruption of primary teeth
		b. Sleeping with a bottle
		c. Congenital syphilis
		d. Vitamin B deficiency
A baby that sleeps with a bottle of milk is the primary cause of ECC, which is a condition involving extensive acute caries. Milk, even breast milk, has a lot of sugar in it that can cause rapid formation of caries in a child's primary teeth. The guardian of the child should remove the bottle and use a damp cloth or baby brush to clean out and remove the sugar from the child's mouth after feeding. Incorrect answer. Please choose another answer.

41.	When taking a dental radiographic, if the tube head is improperly positioned, and the center of the beam misses the center of the sensor/film cutting off the edge of the focal spot and creating a blank space, it is known as:
		a. Cone cut
		b. Elongation
		c. A ghost image
		d. Foreshortening
Cone cut is a common placement error, where the tube head is improperly positioned and the resulting image displays a curved white area from the light reflecting the cone of the tube head. Another plausible answer would be a ghost image as that choice makes sense due to the description of the error involving a blank space. However, a ghost image occurs from the scattering of light and usually results in a shadow from another source such as from the spine or a cataract. Incorrect answer. Please choose another answer.

42.	When would you take a periapical image instead of a bitewing?
		a. To detect caries
		b. To evaluate bone levels
		c. To see the root of a tooth
		d. To evaluate an older restoration
Bitewings are the more commonly used radiograph. They allow the clinician to see a close up of the interproximal areas, or in between the contacts of the teeth. This allows the dentist to detect caries and evaluate older restorations. You can also detect changes in bone levels over time by comparing older bitewings. You would take a periapical image when you want to see the root of the tooth to evaluate for an abscess, deep decay, or other pathology. Incorrect answer. Please choose another answer.

43.	All of the following indicate the need to perform scaling and root planing (SRP) on a patient, except:
		a. Heavy wall of supragingival tartar
		b. Bleeding when probing
		c. Generalized 4+mm pockets
		d. Radiographic bone loss
		e. Presence of subgingival calculus
A heavy wall of supragingival tartar, even when completely covering the teeth, is not a true indicator of the need for SRP. Some patients build up heavier, and actually need shorter recall appointments or a debridement, but the amount of tartar itself does not indicate this type of treatment. SRP is needed when both scaling and planing of the root need to be performed, due to tartar stuck subgingivally causing bleeding gums and deep pockets. If tartar is not removed, this can eventually lead to bone loss, which can be detected radiographically. Incorrect answer. Please choose another answer.

44.	What is enamel primarily composed of?
		a. Calcium
		b. Water
		c. Organic matrix
		d. Hydroxyapatite
Enamel's composition can be broken down to: 87% hydroxyapatite, 11% water, and 2% organic matrix. Another plausible answer would have been Calcium, as hydroxyapatite is partially composed of calcium as well as the organic matrix. However, the main structural component of tooth enamel is the substance, hydroxyapatite itself. Incorrect answer. Please choose another answer.

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45.	Acidity produced when the bacteria in foods break down causes demineralization of enamel. At what level pH does enamel begin to demineralize?
		a. Below 4.5
		b. Below 5.5
		c. Below 7
		d. Below 8
pH has to drop below 5.5 to begin demineralizing enamel. Below 7 is another plausible answer, as once the pH drops below 7 it begins to enter into an acidic state. However, acidity does not start to break down enamel until it drops below 5.5. Incorrect answer. Please choose another answer.

46.	Which protein found in saliva is the most prominent defender against bacterial injuries within the oral cavity?
		a. Amylase
		b. Mucin
		c. Lysozyme
		d. Lactoferrin
Lactoferrin has antibacterial properties to fight against Gram-positive and Gram-negative bacteria. It acts as a protective barrier on mucosal surfaces and can potentially be used as a natural antibiotic. Incorrect answer. Please choose another answer.

47.	Drugs are classified into five categories, or Schedules, to differentiate between drugs used for medical use and to identify drugs with higher drug dependency. Which category does heroin fall under?
		a. Schedule I
		b. Schedule II
		c. Schedule III
		d. Schedule IV
		e. Schedule V
Schedule I is the category of drugs with no acceptable medical use and that have a high risk of dependency and abuse. Heroin is in Schedule I. This question may be tricky, as some people may think the higher the schedule, the more intense the drug, and assume heroin would fall under Schedule V. However, Schedule V have the lowest potential for abuse, such as Robitussin. Incorrect answer. Please choose another answer.

48.	Which drug is considered a broad spectrum drug since it can kill a wide variety of bacteria, but should not be given to children under 12 or pregnant women as it can cause discoloration on developing teeth?
		a. Ampicillin
		b. Tetracycline
		c. Fluoride
		d. Erythromycin
Tetracycline is an antibiotic that is known for causing staining on a child's teeth when ingested by a pregnant woman or to the child while their teeth are still developing. Fluoride can also cause staining to the teeth if ingested in excess. This condition is called fluorosis, however fluoride is not a drug. Incorrect answer. Please choose another answer.

49.	Where is the incisive papilla located?
		a. Tongue
		b. Attached gingiva
		c. Hard palate
		d. Free gingiva
The incisive papilla is located at the midline of the anterior hard palate between teeth #8 and #9, or the central maxillary incisors. Most of the papillae in the oral cavity are located on the dorsal surface of the tongue, however this specific structure is located on the roof of the mouth. Incorrect answer. Please choose another answer.

50.	Which of the following natural sugars are considered the best substitute for traditional sugar?
		a. Xylitol
		b. Stevia
		c. Fructose
		d. Lactose
Xylitol is a natural sugar that actually has remineralizing properties and can be used to prevent cavities. Stevia is a great substitute for traditional white sugar, but the best substitute for your teeth and enamel is xylitol. Incorrect answer. Please choose another answer.

Quality starts with who wrote the material.

Our practice exam writer

Sharon Boyd, RDH

, has been a registered dental hygienist for over 10 years. She specializes in creating educational material for dental studies and has been a head continuing education curriculum writer for an American Dental Association CERP provider.

Abby Altergott, RDH

, has been a registered dental hygienist for over 8 years. She has worked in the specialties of oral surgery, periodontics and orthodontics.

Licensing of dental hygienists in the U.S. is regulated by the individual states. Currently, all states and the District of Columbia, Puerto Rico, Guam and the Virgin Islands recognize exam results from the National Board of Dental Hygiene Exam (NBDHE). The exam assesses a hygienist’s ability to understand relevant information including basic biomedical, dental and dental hygiene sciences and the ability to apply the information into a problem-solving context.

The NBDHE consists of 350 questions. There are 2 components to the NBDHE:

Discipline-based questions on the following three areas:

Scientific Basis for Dental Hygiene Practice
Provision of Clinical Dental Hygiene Services
Community Health/Research Principles.

Dental Hygiene Patient Cases containing 12-15 patient cases addressing the following knowledge and skill areas:

Assessing patient characteristics
Obtaining and interpreting radiographs
Planning and managing dental hygiene care
Performing periodontal procedures
Using preventive agents
Providing supportive treatment service
Professional responsibility

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