RDA Dental Charting, Tooth Morphology, and Occlusion 4 — Questions and Answers
Question 1: Which tooth has a distinctly heart-shaped cross-section at the cervical third?
- Maxillary central incisor (Correct answer)
- Mandibular first molar
- Maxillary first premolar
- Maxillary canine
Correct answer: Maxillary central incisor
The maxillary central incisor has a heart-shaped (triangular) cross-section at the cervical third due to its labial convexity and lingual concavity.
Question 2: In the Universal Numbering System, which tooth is #17?
- Mandibular left second molar
- Mandibular left third molar (Correct answer)
- Mandibular right third molar
- Mandibular left first molar
Correct answer: Mandibular left third molar
In the Universal system, #17 is the mandibular left third molar; numbering continues from #16 (maxillary left third molar) around the arch.
Question 3: A charting symbol of a red circle drawn around an existing restoration indicates:
- A tooth that needs to be extracted
- A restoration present that is defective or needs replacement (Correct answer)
- A tooth that is impacted
- An area of recurrent decay only
Correct answer: A restoration present that is defective or needs replacement
A red circle or outline around a charting symbol denotes an existing condition that is defective and requires treatment.
Question 4: Which cusp of the maxillary first molar is the smallest and located on the mesiolingual line angle?
- Cusp of Carabelli (Correct answer)
- Distolingual cusp
- Mesiolingual cusp
- Distobuccal cusp
Correct answer: Cusp of Carabelli
The cusp of Carabelli is an anomalous fifth cusp found on the mesiolingual surface of the maxillary first molar and is the smallest cusp.
Question 5: In Angle's Class II Division 2 malocclusion, how are the maxillary central incisors positioned?
- Labially flared
- Lingually inclined (retroclined) (Correct answer)
- Edge-to-edge
- Proclined with spacing
Correct answer: Lingually inclined (retroclined)
Class II Division 2 is characterized by a distal molar relationship with maxillary central incisors that are retroclined (tipped lingually).
Question 6: The buccal groove of the mandibular first molar separates which two cusps?
- Mesiolingual and distolingual cusps
- Mesiobuccal and distobuccal cusps (Correct answer)
- Distobuccal and distal cusps
- Mesiobuccal and mesiolingual cusps
Correct answer: Mesiobuccal and distobuccal cusps
The buccal groove of the mandibular first molar runs cervically between the mesiobuccal and distobuccal cusps on the buccal surface.
Question 7: When charting, the abbreviation 'PFM' refers to which type of restoration?
- Porcelain fused to metal crown (Correct answer)
- Partial full-mouth restoration
- Periapical fibrous mass
- Porcelain full margin
Correct answer: Porcelain fused to metal crown
PFM stands for porcelain fused to metal, a common crown type combining a metal substructure with a porcelain veneer.
RDA Dental Charting, Tooth Morphology, and Occlusion 4
Which tooth has a distinctly heart-shaped cross-section at the cervical third?