RDA EXAM CALIFORNIA EXAM 2026 (Actual Exam)
Questions with verified Answers (Latest Update
2026) UPDATE!!
1. Which of the following is the primary purpose of wearing gloves in dental practice?
A) To protect the patient from the assistant's hand flora
B) To provide a barrier against bloodborne pathogens
C) To improve grip on instruments
D) To keep hands clean
Answer: B
Rationale:
Gloves serve as a critical barrier to prevent the transmission of bloodborne pathogens such as hepatitis B,
hepatitis C, and HIV between the dental assistant and the patient. They are a key component of standard
precautions and must be changed between patients and whenever torn or contaminated.
2. What is the recommended contact time for an EPA-registered hospital disinfectant used on
environmental surfaces?
A) 10 seconds
B) 1 minute
C) 10 minutes
D) 30 minutes
Answer: C
Rationale:
Most EPA-registered hospital disinfectants require a contact time of 10 minutes to achieve effective kill of
microorganisms on environmental surfaces. The contact time is specified on the product label and must be
followed exactly for disinfection to be effective.
3. Which of the following must be sterilized between patients?
A) X-ray film holders
B) Lead apron
,C) Dental chair
D) Light handle covers
Answer: A
Rationale:
X-ray film holders (positioning devices) are semicritical items that contact mucous membranes or are
contaminated with saliva and blood. They must be sterilized or receive high-level disinfection between
patients. Lead aprons, dental chairs, and light handles are covered with barriers or disinfected with an EPA-
registered disinfectant.
4. What is the correct sequence for donning personal protective equipment (PPE)?
A) Gloves, mask, eyewear, gown
B) Gown, mask, eyewear, gloves
C) Mask, gloves, gown, eyewear
D) Eyewear, gown, mask, gloves
Answer: B
Rationale:
The correct sequence for donning PPE is: gown first, then mask, then eyewear, and finally gloves. Gloves are
put on last to avoid contaminating the other PPE. Hand hygiene must be performed before donning PPE.
5. What is the maximum acceptable level of radiation exposure for a dental assistant per year?
A) 0.5 rem (5 mSv)
B) 1 rem (10 mSv)
C) 5 rem (50 mSv)
D) 10 rem (100 mSv)
Answer: C
Rationale:
The annual occupational exposure limit for radiation workers is 5 rem (50 mSv) per year. The ALARA (As
Low As Reasonably Achievable) principle should always be followed to minimize exposure. Pregnant
workers have a lower limit of 0.5 rem (5 mSv) for the entire pregnancy.
6. Which of the following is the most effective method for sterilizing dental instruments?
A) Chemical disinfection
B) Autoclave (steam under pressure)
2
,C) Dry heat oven
D) Ultrasonic cleaning
Answer: B
Rationale:
The autoclave uses steam under pressure to achieve sterilization, which is the most effective and commonly
used method in dentistry. It kills all microorganisms, including spores. Dry heat is also effective but requires
longer times. Chemical disinfection and ultrasonic cleaning are not sterilization methods.
7. What is the purpose of a spore test in a dental office?
A) To test for hepatitis B
B) To monitor the effectiveness of the sterilization process
C) To test for tuberculosis
D) To test water quality
Answer: B
Rationale:
Spore tests (biological monitors) use Geobacillus stearothermophilus spores to verify that the autoclave is
killing even the most resistant microorganisms. They should be performed at least weekly and documented.
They do not test for specific diseases or water quality.
8. When should dental assistants perform hand hygiene?
A) Only before patient care
B) Only after patient care
C) Before and after patient care, and after removing gloves
D) Only when hands are visibly soiled
Answer: C
Rationale:
Hand hygiene must be performed before and after every patient contact, after removing gloves, and after
touching contaminated surfaces. Even if gloves are worn, hand hygiene is required because gloves can have
microscopic tears and contamination can occur during removal.
9. Which of the following is a critical item in dentistry?
A) Dental chair
B) X-ray machine
3
, C) Surgical scalpel
D) Light handle
Answer: C
Rationale:
Critical items are those that penetrate soft tissue or bone, such as surgical instruments, scalpels, and forceps.
They must be sterilized between patients. Semicritical items contact mucous membranes but do not
penetrate. Noncritical items contact intact skin.
10. What is the correct order for removing PPE?
A) Gloves, eyewear, gown, mask
B) Mask, gloves, gown, eyewear
C) Gown, mask, gloves, eyewear
D) Eyewear, gown, gloves, mask
Answer: A
Rationale:
The correct sequence for removing PPE is: gloves first (most contaminated), then eyewear, then gown, and
finally mask. Hand hygiene must be performed immediately after removing all PPE. Mask is removed last to
avoid contaminating the face.
11. Which type of radiograph shows the entire tooth and surrounding bone?
A) Bitewing
B) Periapical
C) Occlusal
D) Panoramic
Answer: B
Rationale:
A periapical radiograph shows the entire tooth from crown to root apex, along with surrounding bone.
Bitewings show the crowns of upper and lower teeth and interproximal areas. Occlusal shows a larger area
of the arch. Panoramic shows the entire dentition and jaws.
12. What is the recommended position of the dental assistant during radiograph exposure?
A) Behind the patient
B) At least 6 feet from the tubehead, out of the primary beam
4
Questions with verified Answers (Latest Update
2026) UPDATE!!
1. Which of the following is the primary purpose of wearing gloves in dental practice?
A) To protect the patient from the assistant's hand flora
B) To provide a barrier against bloodborne pathogens
C) To improve grip on instruments
D) To keep hands clean
Answer: B
Rationale:
Gloves serve as a critical barrier to prevent the transmission of bloodborne pathogens such as hepatitis B,
hepatitis C, and HIV between the dental assistant and the patient. They are a key component of standard
precautions and must be changed between patients and whenever torn or contaminated.
2. What is the recommended contact time for an EPA-registered hospital disinfectant used on
environmental surfaces?
A) 10 seconds
B) 1 minute
C) 10 minutes
D) 30 minutes
Answer: C
Rationale:
Most EPA-registered hospital disinfectants require a contact time of 10 minutes to achieve effective kill of
microorganisms on environmental surfaces. The contact time is specified on the product label and must be
followed exactly for disinfection to be effective.
3. Which of the following must be sterilized between patients?
A) X-ray film holders
B) Lead apron
,C) Dental chair
D) Light handle covers
Answer: A
Rationale:
X-ray film holders (positioning devices) are semicritical items that contact mucous membranes or are
contaminated with saliva and blood. They must be sterilized or receive high-level disinfection between
patients. Lead aprons, dental chairs, and light handles are covered with barriers or disinfected with an EPA-
registered disinfectant.
4. What is the correct sequence for donning personal protective equipment (PPE)?
A) Gloves, mask, eyewear, gown
B) Gown, mask, eyewear, gloves
C) Mask, gloves, gown, eyewear
D) Eyewear, gown, mask, gloves
Answer: B
Rationale:
The correct sequence for donning PPE is: gown first, then mask, then eyewear, and finally gloves. Gloves are
put on last to avoid contaminating the other PPE. Hand hygiene must be performed before donning PPE.
5. What is the maximum acceptable level of radiation exposure for a dental assistant per year?
A) 0.5 rem (5 mSv)
B) 1 rem (10 mSv)
C) 5 rem (50 mSv)
D) 10 rem (100 mSv)
Answer: C
Rationale:
The annual occupational exposure limit for radiation workers is 5 rem (50 mSv) per year. The ALARA (As
Low As Reasonably Achievable) principle should always be followed to minimize exposure. Pregnant
workers have a lower limit of 0.5 rem (5 mSv) for the entire pregnancy.
6. Which of the following is the most effective method for sterilizing dental instruments?
A) Chemical disinfection
B) Autoclave (steam under pressure)
2
,C) Dry heat oven
D) Ultrasonic cleaning
Answer: B
Rationale:
The autoclave uses steam under pressure to achieve sterilization, which is the most effective and commonly
used method in dentistry. It kills all microorganisms, including spores. Dry heat is also effective but requires
longer times. Chemical disinfection and ultrasonic cleaning are not sterilization methods.
7. What is the purpose of a spore test in a dental office?
A) To test for hepatitis B
B) To monitor the effectiveness of the sterilization process
C) To test for tuberculosis
D) To test water quality
Answer: B
Rationale:
Spore tests (biological monitors) use Geobacillus stearothermophilus spores to verify that the autoclave is
killing even the most resistant microorganisms. They should be performed at least weekly and documented.
They do not test for specific diseases or water quality.
8. When should dental assistants perform hand hygiene?
A) Only before patient care
B) Only after patient care
C) Before and after patient care, and after removing gloves
D) Only when hands are visibly soiled
Answer: C
Rationale:
Hand hygiene must be performed before and after every patient contact, after removing gloves, and after
touching contaminated surfaces. Even if gloves are worn, hand hygiene is required because gloves can have
microscopic tears and contamination can occur during removal.
9. Which of the following is a critical item in dentistry?
A) Dental chair
B) X-ray machine
3
, C) Surgical scalpel
D) Light handle
Answer: C
Rationale:
Critical items are those that penetrate soft tissue or bone, such as surgical instruments, scalpels, and forceps.
They must be sterilized between patients. Semicritical items contact mucous membranes but do not
penetrate. Noncritical items contact intact skin.
10. What is the correct order for removing PPE?
A) Gloves, eyewear, gown, mask
B) Mask, gloves, gown, eyewear
C) Gown, mask, gloves, eyewear
D) Eyewear, gown, gloves, mask
Answer: A
Rationale:
The correct sequence for removing PPE is: gloves first (most contaminated), then eyewear, then gown, and
finally mask. Hand hygiene must be performed immediately after removing all PPE. Mask is removed last to
avoid contaminating the face.
11. Which type of radiograph shows the entire tooth and surrounding bone?
A) Bitewing
B) Periapical
C) Occlusal
D) Panoramic
Answer: B
Rationale:
A periapical radiograph shows the entire tooth from crown to root apex, along with surrounding bone.
Bitewings show the crowns of upper and lower teeth and interproximal areas. Occlusal shows a larger area
of the arch. Panoramic shows the entire dentition and jaws.
12. What is the recommended position of the dental assistant during radiograph exposure?
A) Behind the patient
B) At least 6 feet from the tubehead, out of the primary beam
4
