DDS Prosthodontics and Restorative Dentistry 1 — Questions and Answers
Question 1: The Angle classification of malocclusion is based on the relationship between which teeth?
- Upper and lower central incisors
- Maxillary and mandibular first permanent molars (and maxillary canine to lower first premolar) (Correct answer)
- Upper and lower second premolars
- Maxillary and mandibular canines only
Correct answer: Maxillary and mandibular first permanent molars (and maxillary canine to lower first premolar)
Angle's classification uses the mesiobuccal cusp of the upper first molar relative to the buccal groove of the lower first molar (and canine to premolar) as reference points.
Question 2: Which restorative material has the highest compressive strength and is most indicated for posterior stress-bearing restorations?
- Glass ionomer cement
- Composite resin
- Amalgam (Correct answer)
- Zinc phosphate cement
Correct answer: Amalgam
Dental amalgam has compressive strength of approximately 380–550 MPa, superior to composites and glass ionomers, making it durable for load-bearing posterior restorations.
Question 3: In complete denture fabrication, the Gothic arch (needle point) tracing is used to determine:
- The vertical dimension of occlusion
- The centric relation position of the mandible (Correct answer)
- The horizontal overlap (overjet) of the anterior teeth
- The curve of Spee for posterior teeth placement
Correct answer: The centric relation position of the mandible
The Gothic arch (arrowhead) tracing records centric relation — the apex of the arrow points to the most retruded, unstrained condylar position.
Question 4: The function of a surveyor in removable partial denture fabrication is to:
- Measure the vertical dimension of the edentulous ridge
- Determine the path of insertion and location of undercuts on abutment teeth (Correct answer)
- Calculate the occlusal vertical dimension at rest
- Evaluate the fit of the final metal framework on stone casts
Correct answer: Determine the path of insertion and location of undercuts on abutment teeth
A dental surveyor identifies the height of contour, undercut areas, and parallel surfaces on abutment teeth to design the path of insertion and RPD framework.
Question 5: Post-operative sensitivity after posterior composite resin placement is most commonly attributed to:
- Fluoride release from the composite
- Polymerization shrinkage creating gap formation at the cavity margins (Correct answer)
- Allergic reaction to bis-GMA resin
- Excessive occlusal contacts on the new restoration
Correct answer: Polymerization shrinkage creating gap formation at the cavity margins
Composite polymerization shrinkage (approximately 1.5–3%) can create microleakage gaps at the dentin interface, allowing fluid movement in dentinal tubules and causing post-op sensitivity.
Question 6: The path of insertion of a complete denture is established perpendicular to:
- The occlusal plane of the posterior teeth
- The mean foundation plane of the residual ridges (Correct answer)
- The Frankfort horizontal plane
- The incisal plane of the anterior teeth
Correct answer: The mean foundation plane of the residual ridges
The path of insertion of a complete denture is determined perpendicular to the mean foundation plane, ensuring maximum border seal and minimal tissue displacement.
DDS Prosthodontics and Restorative Dentistry 1
The Angle classification of malocclusion is based on the relationship between which teeth?