Certified Dental Technician (CDT) Exam Prep 2026 | 200
Practice Questions with Answers & Rationales | Dental
Laboratory Study Guide
SECTION A – Complete Dentures & Removable Prosthodontics
1. A 72-year-old edentulous patient with severely resorbed mandibular ridge presents for a complete
denture. During jaw relation recording, you notice the denture base rotates anteriorly when the patient
opens wide. What is the most likely cause?
A. Overextended labial flange
B. Insufficient posterior palatal seal
C. Lack of adequate relief for the mental foramen
D. Inadequate border molding in the retromylohyoid area
Answer: D
Explanation: Rotation on opening indicates poor extension or lack of seal in the retromylohyoid region,
which controls horizontal mandibular movement.
2. A complete denture patient complains of soreness on the lingual aspect of the mandibular ridge near
the premolars. Intraoral exam reveals a sharp bony prominence. Which anatomical structure is most
likely causing this?
A. Genial tubercles
B. Mylohyoid ridge
C. Mental foramen
D. Retromolar pad
Answer: B
Explanation: The mylohyoid ridge can be sharp and undercut; insufficient relief in denture base causes
lingual soreness in the premolar area.
3. During processing of a maxillary complete denture, the acrylic resin undergoes volumetric shrinkage.
Which area is most critical to compensate for shrinkage to maintain peripheral seal?
A. Posterior palatal seal area
,B. Labial frenum notch
C. Hamular notch
D. Midpalatal raphe
Answer: A
Explanation: Posterior palatal seal must be slightly compressed; shrinkage here would break the seal.
Processing compensations include adding wax in this zone.
4. A dentist requests a lingualized occlusion for a mandibular complete denture opposing a maxillary
conventional denture. Which articulator setting is most critical to achieve this?
A. Incisal guidance at 10 degrees
B. Balancing side contacts with 0.5 mm separation
C. Condylar inclination set to patient’s protrusive record
D. Immediate side shift (Bennett movement) set to 15 degrees
Answer: C
Explanation: Lingualized occlusion relies on proper condylar guidance to allow maxillary palatal cusps to
contact mandibular central fossae without balancing interferences.
5. A lab receives a mandibular denture for rebasing. The old denture has a cracked base but good
occlusion. The technician removes the teeth and processes new acrylic. After curing, the teeth do not fit
the cast. What is the most likely error?
A. Failure to use a stone index of tooth position before removing teeth
B. Overpacking the acrylic during trial packing
C. Using a long curing cycle at 165°F
D. Not soaking the teeth in monomer before packing
Answer: A
Explanation: Without a silicone or stone index to preserve the original tooth arrangement, teeth shift
during rebasing, leading to misfit.
6. A patient with a flabby maxillary anterior ridge requires a complete denture. Which impression
technique minimizes tissue displacement in this area?
A. Single-step mucocompressive impression
,B. Window technique with minimal pressure in flabby zone
C. Dual-arch impression with heavy-body material
D. Vacuum-formed splint with self-curing acrylic
Answer: B
Explanation: The window technique (relieving the tray over the flabby tissue) allows impression material
to record the tissue at rest, not compressed.
7. During try-in of a maxillary complete denture, the central incisors are 3 mm below the lip line at rest,
but the patient shows excessive tooth display when smiling. The lab remakes the denture. What
measurement was likely omitted?
A. Interpupillary line orientation
B. High lip line measurement in repose vs. smile
C. Vertical dimension at rest minus 2 mm
D. Horizontal overlap of canines
Answer: B
Explanation: High lip line during smile determines incisal edge position; using only rest lip line leads to
excessive display upon smiling.
8. A complete denture processed with heat-cured acrylic exhibits porosity throughout the palatal region.
The flask was packed with a dry/powder ratio of 3:1 (polymer:monomer). Which correction is most
appropriate?
A. Decrease curing temperature to 140°F
B. Increase monomer to achieve 2.5:1 ratio
C. Add a plasticizer to the mix
D. Apply pressure of 2,000 psi during packing
Answer: B
Explanation: Porosity from insufficient monomer (dry mix). Correct ratio for heat-cured acrylic is ~2.5:1
(polymer:monomer) by volume.
9. A mandibular denture fractures repeatedly along the midline. The denture has a lingual flange
thickness of 1.5 mm. What reinforcement should the technician add in the remake?
A. High-impact acrylic only
, B. Metal mesh embedded 1 mm from tissue surface
C. Glass fiber reinforcement in the incisal third
D. Increase palatal thickness to 3 mm
Answer: B
Explanation: Metal mesh (stainless steel or chrome-cobalt) placed within the acrylic, not on tissue side,
significantly increases fracture resistance in thin areas.
10. A patient cannot achieve suction with a new maxillary denture. The posterior palatal seal is absent.
Which anatomical landmark should the technician mark on the master cast to create a proper seal?
A. Fovea palatinae
B. Vibrating line (junction of movable and immovable tissue)
C. Greater palatine foramen
D. Hamular process
Answer: B
Explanation: The posterior palatal seal is placed along the vibrating line, just posterior to the fovea
palatinae, to create a complete seal.
11. When setting mandibular posterior teeth for a Class II skeletal relationship (retrognathic mandible),
which modification optimizes stability?
A. Set all posterior teeth in crossbite
B. Set second molars as mesial cantilevers
C. Reverse articulation (maxillary lingual cusps contacting mandibular buccal cusps)
D. Use 20-degree cuspal teeth with maxillary teeth set 2 mm buccal
Answer: C
Explanation: Reverse articulation (lingualized occlusion with maxillary buccal cusps contacting
mandibular central fossae) improves stability in Class II.
12. A technician notices that a complete denture’s occlusal vertical dimension (OVD) is 4 mm excessive
at try-in. The teeth were set with a Fox plane guide set at 110 mm from the incisal edge to the ala-tragus
line. What is the immediate corrective action?
A. Reduce the mandibular posterior teeth occlusal height
Practice Questions with Answers & Rationales | Dental
Laboratory Study Guide
SECTION A – Complete Dentures & Removable Prosthodontics
1. A 72-year-old edentulous patient with severely resorbed mandibular ridge presents for a complete
denture. During jaw relation recording, you notice the denture base rotates anteriorly when the patient
opens wide. What is the most likely cause?
A. Overextended labial flange
B. Insufficient posterior palatal seal
C. Lack of adequate relief for the mental foramen
D. Inadequate border molding in the retromylohyoid area
Answer: D
Explanation: Rotation on opening indicates poor extension or lack of seal in the retromylohyoid region,
which controls horizontal mandibular movement.
2. A complete denture patient complains of soreness on the lingual aspect of the mandibular ridge near
the premolars. Intraoral exam reveals a sharp bony prominence. Which anatomical structure is most
likely causing this?
A. Genial tubercles
B. Mylohyoid ridge
C. Mental foramen
D. Retromolar pad
Answer: B
Explanation: The mylohyoid ridge can be sharp and undercut; insufficient relief in denture base causes
lingual soreness in the premolar area.
3. During processing of a maxillary complete denture, the acrylic resin undergoes volumetric shrinkage.
Which area is most critical to compensate for shrinkage to maintain peripheral seal?
A. Posterior palatal seal area
,B. Labial frenum notch
C. Hamular notch
D. Midpalatal raphe
Answer: A
Explanation: Posterior palatal seal must be slightly compressed; shrinkage here would break the seal.
Processing compensations include adding wax in this zone.
4. A dentist requests a lingualized occlusion for a mandibular complete denture opposing a maxillary
conventional denture. Which articulator setting is most critical to achieve this?
A. Incisal guidance at 10 degrees
B. Balancing side contacts with 0.5 mm separation
C. Condylar inclination set to patient’s protrusive record
D. Immediate side shift (Bennett movement) set to 15 degrees
Answer: C
Explanation: Lingualized occlusion relies on proper condylar guidance to allow maxillary palatal cusps to
contact mandibular central fossae without balancing interferences.
5. A lab receives a mandibular denture for rebasing. The old denture has a cracked base but good
occlusion. The technician removes the teeth and processes new acrylic. After curing, the teeth do not fit
the cast. What is the most likely error?
A. Failure to use a stone index of tooth position before removing teeth
B. Overpacking the acrylic during trial packing
C. Using a long curing cycle at 165°F
D. Not soaking the teeth in monomer before packing
Answer: A
Explanation: Without a silicone or stone index to preserve the original tooth arrangement, teeth shift
during rebasing, leading to misfit.
6. A patient with a flabby maxillary anterior ridge requires a complete denture. Which impression
technique minimizes tissue displacement in this area?
A. Single-step mucocompressive impression
,B. Window technique with minimal pressure in flabby zone
C. Dual-arch impression with heavy-body material
D. Vacuum-formed splint with self-curing acrylic
Answer: B
Explanation: The window technique (relieving the tray over the flabby tissue) allows impression material
to record the tissue at rest, not compressed.
7. During try-in of a maxillary complete denture, the central incisors are 3 mm below the lip line at rest,
but the patient shows excessive tooth display when smiling. The lab remakes the denture. What
measurement was likely omitted?
A. Interpupillary line orientation
B. High lip line measurement in repose vs. smile
C. Vertical dimension at rest minus 2 mm
D. Horizontal overlap of canines
Answer: B
Explanation: High lip line during smile determines incisal edge position; using only rest lip line leads to
excessive display upon smiling.
8. A complete denture processed with heat-cured acrylic exhibits porosity throughout the palatal region.
The flask was packed with a dry/powder ratio of 3:1 (polymer:monomer). Which correction is most
appropriate?
A. Decrease curing temperature to 140°F
B. Increase monomer to achieve 2.5:1 ratio
C. Add a plasticizer to the mix
D. Apply pressure of 2,000 psi during packing
Answer: B
Explanation: Porosity from insufficient monomer (dry mix). Correct ratio for heat-cured acrylic is ~2.5:1
(polymer:monomer) by volume.
9. A mandibular denture fractures repeatedly along the midline. The denture has a lingual flange
thickness of 1.5 mm. What reinforcement should the technician add in the remake?
A. High-impact acrylic only
, B. Metal mesh embedded 1 mm from tissue surface
C. Glass fiber reinforcement in the incisal third
D. Increase palatal thickness to 3 mm
Answer: B
Explanation: Metal mesh (stainless steel or chrome-cobalt) placed within the acrylic, not on tissue side,
significantly increases fracture resistance in thin areas.
10. A patient cannot achieve suction with a new maxillary denture. The posterior palatal seal is absent.
Which anatomical landmark should the technician mark on the master cast to create a proper seal?
A. Fovea palatinae
B. Vibrating line (junction of movable and immovable tissue)
C. Greater palatine foramen
D. Hamular process
Answer: B
Explanation: The posterior palatal seal is placed along the vibrating line, just posterior to the fovea
palatinae, to create a complete seal.
11. When setting mandibular posterior teeth for a Class II skeletal relationship (retrognathic mandible),
which modification optimizes stability?
A. Set all posterior teeth in crossbite
B. Set second molars as mesial cantilevers
C. Reverse articulation (maxillary lingual cusps contacting mandibular buccal cusps)
D. Use 20-degree cuspal teeth with maxillary teeth set 2 mm buccal
Answer: C
Explanation: Reverse articulation (lingualized occlusion with maxillary buccal cusps contacting
mandibular central fossae) improves stability in Class II.
12. A technician notices that a complete denture’s occlusal vertical dimension (OVD) is 4 mm excessive
at try-in. The teeth were set with a Fox plane guide set at 110 mm from the incisal edge to the ala-tragus
line. What is the immediate corrective action?
A. Reduce the mandibular posterior teeth occlusal height
