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100+ Free CDT Practice Questions

Pass your NBC Certified Dental Technician (Comprehensive Written Exam) exam on the first try — instant access, no signup required.

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Question 1
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When evaluating a dental impression, which of the following indicates an acceptable impression for laboratory use?

A
B
C
D
to track
2026 Statistics

Key Facts: CDT Exam

160

Scored Questions

NBC CDT Exam Handbook (plus 10 field-test)

2h 45m

Exam Time

NBC CDT Exam Handbook

$275

Comprehensive Exam Fee

NBC fee schedule

7

Specialty Areas

NBC: Ceramics, Complete Dentures, C&B, Digital, Implants, Ortho, Partial

$1,200

Total CDT Certification Cost

NBC: Comprehensive + Specialty + Practical

NBC's CDT Comprehensive Written Exam consists of 160 multiple-choice questions (plus 10 unscored field-test items) with a 2 hour 45 minute time limit. The exam fee is $275. Content domains include Dental Lab Materials (31-33%), Anatomy (16-18%), Safe Working Practices (16-18%), Impressions and Models (10-12%), Regulations (9-11%), Articulation (6-8%), and Theory (5-7%). Full CDT certification requires passing three exams within four years: Comprehensive ($275), Specialty ($275), and Practical ($650).

Sample CDT Practice Questions

Try these sample questions to test your CDT exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1According to FDA CFR 21 Part 820, which document must accompany custom dental devices when shipped from the dental laboratory to the dentist?
A.A marketing brochure
B.A prescription or work authorization from the prescribing dentist
C.A copy of the technician's resume
D.The patient's insurance information
Explanation: Under FDA regulations (21 CFR Part 820 — Quality System Regulation), dental laboratories must manufacture custom dental devices only pursuant to a valid prescription or work authorization from a licensed dentist. This prescription must specify the design, materials, and other requirements for the device and must be retained as part of the laboratory's quality records.
2Which federal regulation requires dental laboratories to follow Good Manufacturing Practices (GMPs)?
A.OSHA 29 CFR 1910
B.FDA 21 CFR Part 820
C.HIPAA Privacy Rule
D.EPA Resource Conservation and Recovery Act
Explanation: FDA 21 CFR Part 820 (Quality System Regulation) establishes Good Manufacturing Practice requirements for medical device manufacturers, including dental laboratories that fabricate custom dental devices. GMPs cover design controls, production and process controls, corrective and preventive actions, and documentation requirements to ensure device safety and efficacy.
3What type of occlusion is characterized by the mesiobuccal cusp of the maxillary first molar occluding in the mesiobuccal groove of the mandibular first molar?
A.Class II malocclusion
B.Class I (normal) occlusion
C.Class III malocclusion
D.Crossbite
Explanation: Angle's Class I occlusion (neutrocclusion) is defined by the mesiobuccal cusp of the maxillary first molar aligning with the mesiobuccal groove of the mandibular first molar. This is considered the ideal or normal anteroposterior molar relationship and serves as the reference point for classifying all other occlusal relationships.
4Which tooth numbering system uses numbers 1 through 32, starting with the maxillary right third molar?
A.Palmer notation system
B.Universal (ADA) numbering system
C.FDI (International) numbering system
D.ISO 3950 system
Explanation: The Universal (ADA) numbering system assigns numbers 1 through 32 to the permanent teeth, beginning with the maxillary right third molar (tooth #1) and ending with the mandibular right third molar (tooth #32). This system is the standard in the United States and is used on dental laboratory prescriptions, insurance claims, and clinical records.
5Which muscle of mastication is the primary elevator of the mandible and is responsible for closing the jaw?
A.Lateral pterygoid
B.Masseter
C.Digastric
D.Geniohyoid
Explanation: The masseter is the primary elevator of the mandible and one of the strongest muscles in the human body relative to its size. It works in conjunction with the temporalis and medial pterygoid muscles to close the jaw during mastication. Understanding the muscles of mastication is essential for designing dental prostheses that function harmoniously with the patient's musculature.
6Type III dental stone is also commonly known by which name?
A.Plaster of Paris
B.Die stone
C.Dental stone (laboratory stone)
D.Type IV improved stone
Explanation: Type III gypsum product is dental stone (also called laboratory stone or hydrocal). It has greater compressive strength and accuracy than Type II plaster but less than Type IV die stone. Type III stone is commonly used for pouring working casts, study models, and mounting casts on articulators in dental laboratory procedures.
7When mounting casts on a semi-adjustable articulator, what is the purpose of a face-bow transfer?
A.To record the patient's tooth shade
B.To transfer the relationship of the maxillary arch to the transverse hinge axis and a reference plane
C.To measure the patient's maximum opening distance
D.To determine the size of the denture teeth
Explanation: A face-bow transfer records the spatial relationship of the maxillary arch to the transverse hinge axis (or an arbitrary hinge axis point) and an anatomical reference plane (typically the orbital plane or Frankfort horizontal plane). This information allows the dental technician to mount the maxillary cast on the articulator in an orientation that closely replicates the patient's jaw relationship to the skull.
8What is the primary advantage of Type IV die stone over Type III dental stone for crown and bridge fabrication?
A.Lower cost
B.Higher compressive strength and greater dimensional accuracy
C.Faster setting time
D.Better color for shade matching
Explanation: Type IV die stone has significantly higher compressive strength (typically 35 MPa or greater) and superior surface hardness and dimensional accuracy compared to Type III dental stone. These properties make it ideal for fabricating individual dies where precise reproduction of tooth preparation margins is critical for the fit of crowns, bridges, and other fixed restorations.
9Which impression material produces the most dimensionally accurate cast when poured immediately?
A.Alginate (irreversible hydrocolloid)
B.Polyvinyl siloxane (PVS / addition silicone)
C.Impression compound
D.Zinc oxide-eugenol
Explanation: Polyvinyl siloxane (PVS), also known as addition silicone, is considered the most dimensionally accurate impression material. It has excellent detail reproduction, minimal polymerization shrinkage, long-term dimensional stability, and high tear strength. PVS can be poured multiple times without loss of accuracy, making it the material of choice for crown, bridge, and implant impressions.
10In the FDI (International) numbering system, what does the number 36 represent?
A.Maxillary right canine
B.Mandibular left first molar
C.Maxillary left second premolar
D.Mandibular right lateral incisor
Explanation: In the FDI system, the first digit indicates the quadrant (1 = upper right, 2 = upper left, 3 = lower left, 4 = lower right for permanent teeth), and the second digit indicates the tooth position counting from the midline (1 = central incisor through 8 = third molar). Tooth 36 is therefore the mandibular left (quadrant 3) first molar (tooth 6).

About the CDT Exam

The CDT Comprehensive Written Exam from NBC tests foundational knowledge across all dental laboratory technology specialties including dental materials science, oral anatomy, safe working practices, articulation, and laboratory regulations. It is the first of three exams required for full CDT certification.

Questions

160 scored questions

Time Limit

2 hours 45 minutes

Passing Score

Criterion-referenced pass/fail

Exam Fee

$275 (NBC)

CDT Exam Content Outline

31-33%

Dental Lab Materials

Gypsum, waxes, metals, alloys, plastics, resins, composites, investments, ceramics, impression materials, abrasives, and polishing agents

16-18%

Anatomy

Occlusion, tooth morphology, numbering systems, anatomic landmarks, muscles of mastication, and facial/cranial skeletal anatomy

16-18%

Safe Working Practices

Equipment safety, PPE, infection control, SDS, hazardous waste disposal, respiratory hazards, and emergency preparedness

10-12%

Impressions and Models

Impression evaluation, model fabrication, custom trays, die fabrication, and impression handling techniques

9-11%

Regulations and Scope of Practice

FDA GMPs (21 CFR 820), OSHA, HIPAA, dental practice act, and CBP labeling requirements

6-8%

Articulation

Articulators, face-bow transfers, bite registrations, centric relation, Bennett angle, and jaw movements

How to Pass the CDT Exam

What You Need to Know

  • Passing score: Criterion-referenced pass/fail
  • Exam length: 160 questions
  • Time limit: 2 hours 45 minutes
  • Exam fee: $275

Keys to Passing

  • Complete 500+ practice questions
  • Score 80%+ consistently before scheduling
  • Focus on highest-weighted sections
  • Use our AI tutor for tough concepts

CDT Study Tips from Top Performers

1Prioritize dental lab materials — this domain alone is 31-33% of the exam and covers gypsum, waxes, metals, ceramics, investments, and resins
2Know the properties and classification of dental alloys: noble vs base metal, ADA classification, and casting characteristics
3Master tooth morphology including cusp patterns, root anatomy, and numbering systems (Universal, FDI, Palmer)
4Study OSHA safety requirements for dental laboratories including SDS, PPE, respiratory protection, and hazardous waste disposal
5Practice articulator concepts: face-bow transfers, Bennett angle, condylar guidance, and centric relation

Frequently Asked Questions

How many questions are on the CDT Comprehensive exam?

The CDT Comprehensive Written Exam has 160 multiple-choice questions. NBC also includes 10 embedded field-test questions that are not scored, bringing the total to 170 items presented. Candidates are not told which items are field-test questions.

How long is the CDT Comprehensive exam?

Candidates have up to 2 hours and 45 minutes to complete the CDT Comprehensive Written Exam.

How much does the CDT Comprehensive exam cost?

The Written Comprehensive exam fee is $275. Full CDT certification requires three exams: Comprehensive ($275), Written Specialty ($275), and Practical ($650), totaling $1,200.

What are the seven CDT specialties?

NBC recognizes seven CDT specialties: Ceramics, Complete Dentures, Crown & Bridge, Digital Workflow, Implants, Orthodontics, and Partial Dentures. Candidates choose one specialty for their Written Specialty and Practical exams.

Can I take the CDT Comprehensive exam remotely?

Yes. NBC administers the CDT written examinations using computer-based testing with remote proctoring. Testing windows run monthly. You need a private workspace, a computer with webcam, and a smartphone.

How should I prepare for the CDT Comprehensive exam?

Focus on dental lab materials (31-33% of the exam) and anatomy (16-18%) as the two largest domains. Use the NBC Examination Preparation Guide and recommended textbooks. Study safety practices and FDA/OSHA regulations thoroughly.