National Board Dental Hygiene Exam NBDHE
Exam 2026 | All Questions and Correct
Answers with Rationales | Verified Answers |
Newest Version | Just Released
Which of the following is a measure of the energy needed to maintain life while at
rest and without food? ---------CORRECT ANSWER-----------------BMR
RATIONALE: Energy for basal metabolism is referred to as the basal metabolic
rate (BMR), which is a measure of energy. The specific dynamic energy (SDE) is a
measure used during metabolism of food. Protein energy malnutrition (PEM), a
potentially fatal protein deficit, is prominent in anorexic individuals, as well as
those in later stages of HIV infection. Coronary heart disease (CHD), is a disease
state, not a measure of energy.
During the intraoral examination, a translucent-to-whitish irregular film on the
buccal mucosa is noted. The film is not removable with gauze. Which of the
following conditions is MOST likely present? ---------CORRECT ANSWER----------------
-Hyperkeratinization
RATIONALE: Hyperkeratinization can result from constant low-grade irritations
such as cheek biting, which causes an abnormal layer of keratin to develop. The
client needs to be questioned regarding parafunctional oral habits. Hyperplasia
is an increase in the number of cells whereas linea alba presents as a whitish,
horizontal, elevated line on the buccal mucosa at the height of the occlusal
plane. Also whitish in appearance, leukoplakia is characterized as white patches
,that sometimes appear fissured, may cause discomfort, cannot be scraped off
and are considered precancerous.
When comparing permanent and primary molars, which of the following
statements is TRUE? ---------CORRECT ANSWER-----------------Primary molars have
larger pulp chambers.
RATIONALE: The pulp chambers of primary molars are larger than those of the
permanent molars. Second primary molars, not first primary molars, have
anatomy similar to that of the first permanent molars. Primary molars have the
same number of roots as permanent molars; note that neither primary molars
nor permanent molars are classified as succedaneous teeth. A succedaneous
tooth is a permanent tooth that replaces a primary tooth. Thus, permanent
incisors are succedaneous, but permanent molars are not. The root trunks of
primary molars are very short in comparison with those of permanent molars
John Jeffry, a 45-year-old man, calls the dental office to request an appointment
for an oral examination. After discovering that he has cerebral palsy, the office
manager tells Mr. Jeffry that he cannot be treated in the office due to his
condition. Which of the following BEST describes the behavior being
demonstrated by the office manager? ---------CORRECT ANSWER-----------------This
behavior is an example of discrimination according to the Americans with
Disabilities Act.
RATIONALE: This illegal behavior is an example of discrimination according to
the Americans with Disabilities Act (ADA). Based upon the ADA, dental practices
can neither refuse treatment based on a client's disability nor can they
prescreen clients to determine whether they will provide care. Although the
,Equal Rights Amendment affords important protection to all citizens, it has no
bearing on the provision of dental treatment.
Which of the following correctly ranks the tissues in order of MOST sensitive to
LEAST sensitive to ionizing radiation? ---------CORRECT ANSWER-----------------
Reproductive, lymphatic, endocrine, digestive, nervous
RATIONALE: In general, younger cells with a high rate of metabolism, an
increased proliferation and growth rate, and a decrease in specialization are
more susceptible to radiation-induced biologic changes. Therefore, reproductive
organs represent tissue with cells that are most radiosensitive, whereas the
nervous system is composed of cells considered to be the most radioresistant.
In descending order of radiosensitivity are lymphatic, endocrine, and digestive
tissues. An important concept, tissues that are less sensitive to radiation-
induced biological changes will be more specialized, have lower rates of
metabolism and decreased proliferation and growth rates.
Which of the following describes a dental implant that is placed on the surface of
the bone beneath the periosteum? ---------CORRECT ANSWER-----------------
Subperiosteal
RATIONALE: A subperiosteal implant is placed on the surface of the bone
beneath the periosteum. Periosseous is not a term associated with a type of
dental implant. An endosseous implant is placed into the alveolar bone whereas
a transosteal implant is placed through the alveolar bone.
, Studies of the natural history of periodontal disease have shown which of the
following to be TRUE? ---------CORRECT ANSWER-----------------Periodontal therapy
and oral self-care will slow the rate of attachment loss in periodontitis.
RATIONALE: In studies of Sri Lanka tea workers, comparison of untreated groups
with regular dental care attendees from Norway documented that periodontal
therapy and self-care slow the rate of clinical attachment loss (0.3 and 0.1 mm,
respectively). Because plaque and calculus are common in treated and
untreated clients, incidence of periodontitis is not affected by the amount these
accretions. Regarding patterns of disease progression, gingivitis will not
necessarily progress to periodontitis, nor does untreated periodontal disease
rapidly progress.
Acidic agents, such as acidulated phosphate fluoride (APF) gels and foams, can
inadvertently dissolve ceramic phases on all of the following surfaces EXCEPT one.
Which one is the EXCEPTION? ---------CORRECT ANSWER-----------------Pit and
fissure sealants
RATIONALE: Inadvertent dissolution of a ceramic phase is not a concern with pit
and fissure sealants because sealants do not contain a ceramic phase that is
vulnerable to dissolution. When a client's treatment plan includes an acidulated
phosphate fluoride gel or foam, the dental hygienist must first assure that
damage from the low pH (acidity) of the solution will not damage any existing
dental restorations. Hybrid composites have glass fillers that can be dissolved by
APF. Porcelain fused-to-metal (PFM) restorations can be partially dissolved by
APF as can CAD/CAM ceramics which are etched during the bonding procedures
by hydrofluoric acid. Also vulnerable to dissolution by APF are porcelain
veneers.
Exam 2026 | All Questions and Correct
Answers with Rationales | Verified Answers |
Newest Version | Just Released
Which of the following is a measure of the energy needed to maintain life while at
rest and without food? ---------CORRECT ANSWER-----------------BMR
RATIONALE: Energy for basal metabolism is referred to as the basal metabolic
rate (BMR), which is a measure of energy. The specific dynamic energy (SDE) is a
measure used during metabolism of food. Protein energy malnutrition (PEM), a
potentially fatal protein deficit, is prominent in anorexic individuals, as well as
those in later stages of HIV infection. Coronary heart disease (CHD), is a disease
state, not a measure of energy.
During the intraoral examination, a translucent-to-whitish irregular film on the
buccal mucosa is noted. The film is not removable with gauze. Which of the
following conditions is MOST likely present? ---------CORRECT ANSWER----------------
-Hyperkeratinization
RATIONALE: Hyperkeratinization can result from constant low-grade irritations
such as cheek biting, which causes an abnormal layer of keratin to develop. The
client needs to be questioned regarding parafunctional oral habits. Hyperplasia
is an increase in the number of cells whereas linea alba presents as a whitish,
horizontal, elevated line on the buccal mucosa at the height of the occlusal
plane. Also whitish in appearance, leukoplakia is characterized as white patches
,that sometimes appear fissured, may cause discomfort, cannot be scraped off
and are considered precancerous.
When comparing permanent and primary molars, which of the following
statements is TRUE? ---------CORRECT ANSWER-----------------Primary molars have
larger pulp chambers.
RATIONALE: The pulp chambers of primary molars are larger than those of the
permanent molars. Second primary molars, not first primary molars, have
anatomy similar to that of the first permanent molars. Primary molars have the
same number of roots as permanent molars; note that neither primary molars
nor permanent molars are classified as succedaneous teeth. A succedaneous
tooth is a permanent tooth that replaces a primary tooth. Thus, permanent
incisors are succedaneous, but permanent molars are not. The root trunks of
primary molars are very short in comparison with those of permanent molars
John Jeffry, a 45-year-old man, calls the dental office to request an appointment
for an oral examination. After discovering that he has cerebral palsy, the office
manager tells Mr. Jeffry that he cannot be treated in the office due to his
condition. Which of the following BEST describes the behavior being
demonstrated by the office manager? ---------CORRECT ANSWER-----------------This
behavior is an example of discrimination according to the Americans with
Disabilities Act.
RATIONALE: This illegal behavior is an example of discrimination according to
the Americans with Disabilities Act (ADA). Based upon the ADA, dental practices
can neither refuse treatment based on a client's disability nor can they
prescreen clients to determine whether they will provide care. Although the
,Equal Rights Amendment affords important protection to all citizens, it has no
bearing on the provision of dental treatment.
Which of the following correctly ranks the tissues in order of MOST sensitive to
LEAST sensitive to ionizing radiation? ---------CORRECT ANSWER-----------------
Reproductive, lymphatic, endocrine, digestive, nervous
RATIONALE: In general, younger cells with a high rate of metabolism, an
increased proliferation and growth rate, and a decrease in specialization are
more susceptible to radiation-induced biologic changes. Therefore, reproductive
organs represent tissue with cells that are most radiosensitive, whereas the
nervous system is composed of cells considered to be the most radioresistant.
In descending order of radiosensitivity are lymphatic, endocrine, and digestive
tissues. An important concept, tissues that are less sensitive to radiation-
induced biological changes will be more specialized, have lower rates of
metabolism and decreased proliferation and growth rates.
Which of the following describes a dental implant that is placed on the surface of
the bone beneath the periosteum? ---------CORRECT ANSWER-----------------
Subperiosteal
RATIONALE: A subperiosteal implant is placed on the surface of the bone
beneath the periosteum. Periosseous is not a term associated with a type of
dental implant. An endosseous implant is placed into the alveolar bone whereas
a transosteal implant is placed through the alveolar bone.
, Studies of the natural history of periodontal disease have shown which of the
following to be TRUE? ---------CORRECT ANSWER-----------------Periodontal therapy
and oral self-care will slow the rate of attachment loss in periodontitis.
RATIONALE: In studies of Sri Lanka tea workers, comparison of untreated groups
with regular dental care attendees from Norway documented that periodontal
therapy and self-care slow the rate of clinical attachment loss (0.3 and 0.1 mm,
respectively). Because plaque and calculus are common in treated and
untreated clients, incidence of periodontitis is not affected by the amount these
accretions. Regarding patterns of disease progression, gingivitis will not
necessarily progress to periodontitis, nor does untreated periodontal disease
rapidly progress.
Acidic agents, such as acidulated phosphate fluoride (APF) gels and foams, can
inadvertently dissolve ceramic phases on all of the following surfaces EXCEPT one.
Which one is the EXCEPTION? ---------CORRECT ANSWER-----------------Pit and
fissure sealants
RATIONALE: Inadvertent dissolution of a ceramic phase is not a concern with pit
and fissure sealants because sealants do not contain a ceramic phase that is
vulnerable to dissolution. When a client's treatment plan includes an acidulated
phosphate fluoride gel or foam, the dental hygienist must first assure that
damage from the low pH (acidity) of the solution will not damage any existing
dental restorations. Hybrid composites have glass fillers that can be dissolved by
APF. Porcelain fused-to-metal (PFM) restorations can be partially dissolved by
APF as can CAD/CAM ceramics which are etched during the bonding procedures
by hydrofluoric acid. Also vulnerable to dissolution by APF are porcelain
veneers.
