NBDHE Clinical Dental Hygiene Final Exam | Actual Questions
and Answers Latest Updated 2026/2027 (Graded A+)
•
Disinfectants kill MOST pathogenic microbes, not?
i. - ✔✔spores
ii. OSHA say no to what type of disinfectant due to toxic effect of fumes and corrosive? -
✔✔glutaraldehydes
iii. Disadvantages to chlorine based compounds (disinfectants) - ✔✔corrosive to metals, strong
odor
iv. Disadvantages to iodophors (disinfectants) - ✔✔can discolor some surfaces yellow
v. Disadvantages to phenols (water or alcohol based disinfectants) - ✔✔may leave film or residue
vi. Disadvantages to quaternary compounds (disinfectant) - ✔✔not corrosive, lower kill spectrum,
limited efficacy
vii. What level of surface disinfectant is used in dental offices? - ✔✔intermediate (must kill TB
organisms)
viii. Conditions for steam sterlization? - ✔✔250 degrees with 15 or 20 lbs psi for 30 min
ix. Conditions for dry heat sterilization? - ✔✔340 degrees for 1 hour or 320 degrees for 2 hours
x. Conditions for chemical sterilization? - ✔✔273 degrees for 20 minutes with 25 psi
xi. Sterility is not guaranteed with? - ✔✔external indicators
xii. Biological indicators (Spore testing) should be conducted? - ✔✔weekly
xiii. Dry heat is recommended for what type of instruments? - ✔✔metal
xiv. Know former and new BP guidelines - ✔✔
xv. Know GV blacks classifications, furcations class and mobility - ✔✔
xvi. Supragingival nutrient source is? - ✔✔saliva
xvii. Subgingival nutrient source is? - ✔✔cervicular fluid and inflammatory exudate
xviii. Black line stain is from? - ✔✔gram positive bacteria (located on cervical 1/3rd of teeth)
xix. Brown stain is from? - ✔✔tea, coffee, fruit juices, and red wine
xx. Dark brown and black stain is from? - ✔✔tobacco use
xxi. Orange stain is from? - ✔✔chromogenic bacteria in plaque
xxii. yellow brown and brown stain is from? - ✔✔chlorhexidine or stannous fluoride use (tin ion)
xxiii. Green stain is from? - ✔✔chromogenic bacteria, fungi, and gingival hemorrhage
xxiv. If stain is located on cementum, choice for removal is? - ✔✔instrumentation
Demineralization process occurs when pH drops below what for enamel? (Critical pH levels)
- ✔✔4.5-5.5
xxv. Demineralization process occurs when pH drops below what for cementum? (Critical pH levels) -
✔✔6.0- 6.7
xxvi. Fluoride interferes with? - ✔✔bacterial metabolism
xxvii. Bactericidal - ✔✔kill bacteria
xxviii. Bacteriostatic - ✔✔inhibits growth (more effective for patient)
xxix. Warmer climate level of fluoride? - ✔✔0.7
xxx. Colder climate level of fluoride? - ✔✔1.2
and Answers Latest Updated 2026/2027 (Graded A+)
•
Disinfectants kill MOST pathogenic microbes, not?
i. - ✔✔spores
ii. OSHA say no to what type of disinfectant due to toxic effect of fumes and corrosive? -
✔✔glutaraldehydes
iii. Disadvantages to chlorine based compounds (disinfectants) - ✔✔corrosive to metals, strong
odor
iv. Disadvantages to iodophors (disinfectants) - ✔✔can discolor some surfaces yellow
v. Disadvantages to phenols (water or alcohol based disinfectants) - ✔✔may leave film or residue
vi. Disadvantages to quaternary compounds (disinfectant) - ✔✔not corrosive, lower kill spectrum,
limited efficacy
vii. What level of surface disinfectant is used in dental offices? - ✔✔intermediate (must kill TB
organisms)
viii. Conditions for steam sterlization? - ✔✔250 degrees with 15 or 20 lbs psi for 30 min
ix. Conditions for dry heat sterilization? - ✔✔340 degrees for 1 hour or 320 degrees for 2 hours
x. Conditions for chemical sterilization? - ✔✔273 degrees for 20 minutes with 25 psi
xi. Sterility is not guaranteed with? - ✔✔external indicators
xii. Biological indicators (Spore testing) should be conducted? - ✔✔weekly
xiii. Dry heat is recommended for what type of instruments? - ✔✔metal
xiv. Know former and new BP guidelines - ✔✔
xv. Know GV blacks classifications, furcations class and mobility - ✔✔
xvi. Supragingival nutrient source is? - ✔✔saliva
xvii. Subgingival nutrient source is? - ✔✔cervicular fluid and inflammatory exudate
xviii. Black line stain is from? - ✔✔gram positive bacteria (located on cervical 1/3rd of teeth)
xix. Brown stain is from? - ✔✔tea, coffee, fruit juices, and red wine
xx. Dark brown and black stain is from? - ✔✔tobacco use
xxi. Orange stain is from? - ✔✔chromogenic bacteria in plaque
xxii. yellow brown and brown stain is from? - ✔✔chlorhexidine or stannous fluoride use (tin ion)
xxiii. Green stain is from? - ✔✔chromogenic bacteria, fungi, and gingival hemorrhage
xxiv. If stain is located on cementum, choice for removal is? - ✔✔instrumentation
Demineralization process occurs when pH drops below what for enamel? (Critical pH levels)
- ✔✔4.5-5.5
xxv. Demineralization process occurs when pH drops below what for cementum? (Critical pH levels) -
✔✔6.0- 6.7
xxvi. Fluoride interferes with? - ✔✔bacterial metabolism
xxvii. Bactericidal - ✔✔kill bacteria
xxviii. Bacteriostatic - ✔✔inhibits growth (more effective for patient)
xxix. Warmer climate level of fluoride? - ✔✔0.7
xxx. Colder climate level of fluoride? - ✔✔1.2
