CSLB General Building (B) Trade Practice Test

Câu hỏi luyện tập mẫu

Một vài câu hỏi thực tế từ ngân hàng miễn phí này, kèm giải thích đầy đủ. Dùng công cụ luyện tập ở trên cho toàn bộ.

1. 1. Radiation Health & Safety

   A dental assistant is asked to explain the ALARA concept to a new hire. Which statement best describes ALARA?

   • a.Radiation exposure is safe as long as it stays under the annual legal limit
   • b.Only the patient's exposure must be minimized, not the operator's
   • c.Every reasonable step should be taken to keep exposure As Low As Reasonably Achievable
   • d.Exposure may be increased if it produces a sharper image

   Đáp án: c

   Giải thích: ALARA stands for As Low As Reasonably Achievable, meaning exposure to patients and staff should be reduced to the lowest practical level even when legal limits are not exceeded. Staying under a legal limit is a minimum requirement, not the goal, so the first option is wrong. ALARA protects both patients and operators, and image quality is achieved through correct technique rather than extra radiation.

   Nguồn: NCRP Report No. 145: Radiation Protection in Dentistry

2. 2. Radiation Health & Safety

   A dental assistant wears a personal dosimeter badge clipped at waist level. What does this badge actually do?

   • a.It blocks scatter radiation from reaching the assistant
   • b.It sounds an alarm when the exposure limit is reached
   • c.It records the assistant's accumulated occupational exposure over a monitoring period
   • d.It measures the output of the x-ray tubehead

   Đáp án: c

   Giải thích: A film or thermoluminescent dosimeter badge records the wearer's accumulated occupational dose, and the monitoring service reports readings so cumulative exposure can be tracked. The badge provides no shielding and does not alarm. Tubehead output is verified separately through equipment testing and calibration, not by a personal badge.

   Nguồn: NCRP Report No. 145: Radiation Protection in Dentistry

3. 3. Radiation Health & Safety

   Most radiation damage in soft tissue happens indirectly. Which mechanism explains this indirect effect?

   • a.X-rays ionize water in the cell, forming free radicals that then damage other molecules
   • b.X-rays strike DNA directly and always break both strands
   • c.X-rays heat the cytoplasm until proteins denature
   • d.X-rays add electrons to the cell nucleus, making it more stable

   Đáp án: a

   Giải thích: Because cells are largely water, most photons ionize water molecules and create highly reactive free radicals, which then damage DNA and other critical molecules; this is the indirect theory. A direct hit on DNA does occur but is far less common, and it does not always break both strands. Radiation injury is ionizing, not thermal, and ionization removes electrons rather than adding them.

4. 4. Radiographic Technique

   Which description matches the paralleling technique for intraoral radiography?

   • a.The receptor rests against the tooth and the beam is aimed at an imaginary bisector
   • b.The receptor is placed parallel to the long axis of the tooth and the central ray is directed perpendicular to both
   • c.The receptor is held by the patient's finger at a 45-degree angle
   • d.The receptor is placed outside the cheek and the beam passes through the face

   Đáp án: b

   Giải thích: In the paralleling technique a holding device positions the receptor parallel to the long axis of the tooth, and the central ray is directed perpendicular to both, which minimizes dimensional distortion. Aiming at an imaginary bisector describes the bisecting technique. Finger holding is discouraged because it causes movement and unnecessary exposure, and placing the receptor outside the cheek describes extraoral imaging.

5. 5. Radiographic Technique

   Films from one box consistently appear gray with poor contrast, even on unexposed control films. What is the most likely explanation?

   • a.The vertical angulation was too steep
   • b.The patient was not wearing a lead apron
   • c.The PID was too long
   • d.Film fog from a light leak, scatter radiation, or outdated or improperly stored film

   Đáp án: d

   Giải thích: Overall grayness with reduced contrast, including on unexposed control films, is classic fog caused by stray light in the darkroom, storage near a radiation source, heat and humidity, or expired film. Angulation errors distort shape, not overall density and contrast. The lead apron does not affect the image, and a longer PID improves sharpness rather than causing fog.

6. 6. Radiographic Technique

   What is the purpose of the raised identification dot on intraoral film, and how should it be oriented during placement?

   • a.It marks the lead foil side and must face away from the beam
   • b.It allows the operator to determine the patient's left and right during mounting, and the convex side faces the beam, toward the occlusal or incisal edge
   • c.It indicates the expiration date and should face the tongue
   • d.It has no clinical function and may be oriented in any direction

   Đáp án: b

   Giải thích: The identification dot establishes orientation so the mounted series can be correctly assigned to the patient's right and left; the raised convex side faces the beam and is positioned toward the occlusal or incisal edge to avoid obscuring apical structures. It does not mark the lead foil, which is on the back of the packet facing away from the beam. The dot carries no date information, and orienting it randomly makes accurate mounting impossible.

7. 7. Infection Control

   How should an instrument processing area be laid out?

   • a.Clean and contaminated items may share one counter as long as they are wiped down
   • b.In a single direction from the contaminated receiving and cleaning area, to preparation and packaging, to sterilization, to clean storage
   • c.Sterile storage should be closest to the sink for convenience
   • d.Packaging should occur before instruments are cleaned

   Đáp án: b

   Giải thích: The processing area must flow in one direction from dirty to clean, moving from receiving and cleaning through preparation and packaging to sterilization and finally to clean storage, so processed items are never recontaminated. Sharing a counter and placing sterile storage next to the dirty sink both invite cross-contamination. Instruments must always be cleaned before packaging, because debris shields microorganisms from the sterilant.

   Nguồn: CDC Guidelines for Infection Control in Dental Health-Care Settings

8. 8. Infection Control

   A countertop is visibly contaminated with blood after an extraction. Which product should be used after the visible blood is cleaned up?

   • a.Plain soap and water only
   • b.A household glass cleaner
   • c.A low-level disinfectant with no tuberculocidal claim
   • d.An EPA-registered intermediate-level hospital disinfectant with a tuberculocidal claim

   Đáp án: d

   Giải thích: Surfaces visibly contaminated with blood require an EPA-registered hospital disinfectant that is intermediate level, meaning it carries a tuberculocidal claim, after the gross contamination has been removed. Soap and water clean but do not disinfect. Glass cleaner is not a registered disinfectant, and a low-level product without a tuberculocidal claim is reserved for surfaces without blood contamination.

   Nguồn: CDC Guidelines for Infection Control in Dental Health-Care Settings

9. 9. Infection Control

   An assistant declines the hepatitis B vaccine that the employer offers. What must happen next?

   • a.The employee must be reassigned to non-clinical duties permanently
   • b.The refusal is noted verbally and no record is kept
   • c.The employee signs the required declination statement, and may still receive the vaccine free of charge later if she changes her mind
   • d.The employee must pay a fee for declining

   Đáp án: c

   Giải thích: An employee who declines must sign the required declination form, and the employer must still provide the vaccination series at no cost if the employee later decides to be vaccinated while still occupationally exposed. A verbal note is not sufficient documentation. Declining is not grounds for reassignment or for any fee or penalty.

   Nguồn: OSHA Bloodborne Pathogens Standard (29 CFR 1910.1030)

10. 10. Patient Safety & Law

    A patient with a history of angina develops crushing chest pain in the chair. Besides stopping treatment and activating emergency medical services, which drug from the office emergency kit is typically indicated?

    • a.Diphenhydramine
    • b.Albuterol inhaler
    • c.Nitroglycerin, administered sublingually
    • d.Oral glucose gel

    Đáp án: c

    Giải thích: Sublingual nitroglycerin is the standard emergency drug for angina because it dilates coronary vessels and relieves ischemic chest pain. Diphenhydramine is used for allergic reactions, and albuterol is for bronchospasm in asthma. Glucose gel treats hypoglycemia and would do nothing for cardiac chest pain, so recognizing the correct emergency category is essential.