DDS Orthodontics and Pediatric Dentistry 2 — Questions and Answers
Question 1: Pulp therapy for a carious primary molar with a normal radiograph and no spontaneous pain, but mechanical pulp exposure, is best treated by:
- Direct pulp cap with calcium hydroxide
- Indirect pulp cap
- Pulpotomy with mineral trioxide aggregate (MTA) or ferric sulfate (Correct answer)
- Immediate extraction
Correct answer: Pulpotomy with mineral trioxide aggregate (MTA) or ferric sulfate
A pulpotomy removes the coronal pulp, which is inflamed from caries proximity, while preserving vital radicular pulp tissue; MTA or ferric sulfate are current evidence-based agents for primary tooth pulpotomy.
Question 2: The primary function of a space maintainer after premature loss of a primary second molar is to:
- Stimulate eruption of the underlying premolar
- Prevent mesial drift of the permanent first molar into the extraction space (Correct answer)
- Guide the permanent canine into proper position
- Maintain the vertical dimension of occlusion
Correct answer: Prevent mesial drift of the permanent first molar into the extraction space
After loss of a primary second molar, the permanent first molar tends to drift mesially, reducing arch length needed for the permanent second premolar; a space maintainer prevents this migration.
Question 3: Molar-incisor hypomineralization (MIH) affects which teeth?
- All primary molars and primary incisors
- First permanent molars and permanent incisors (Correct answer)
- Second permanent molars and canines
- All permanent posterior teeth
Correct answer: First permanent molars and permanent incisors
MIH is defined by demarcated qualitative enamel defects affecting one to four first permanent molars, frequently accompanied by affected permanent incisors.
Question 4: Rapid palatal expansion (RPE) is used to correct:
- Mandibular prognathism
- Bilateral posterior crossbite due to maxillary arch constriction (Correct answer)
- Class II malocclusion by advancing the mandible
- Deep overbite with supraocclusion of incisors
Correct answer: Bilateral posterior crossbite due to maxillary arch constriction
RPE applies transverse forces to open the midpalatal suture, widening the maxillary arch to correct bilateral posterior crossbites caused by maxillary skeletal constriction.
Question 5: Which type of tooth movement requires the most force in orthodontics?
- Tipping
- Torque (root movement)
- Intrusion
- Translation (bodily movement) (Correct answer)
Correct answer: Translation (bodily movement)
Bodily translation requires the entire tooth to move with the root and crown moving equally, demanding greater PDL stimulation area and more controlled force than simple tipping.
Question 6: The recommended fluoride concentration in community water fluoridation as updated by the US Department of Health and Human Services (HHS) is:
- 0.5 ppm
- 0.7 ppm (Correct answer)
- 1.0 ppm
- 1.2 ppm
Correct answer: 0.7 ppm
In 2015, HHS revised the recommended community water fluoride concentration to 0.7 mg/L (ppm) nationwide, down from the previous range of 0.7–1.2 ppm.
DDS Orthodontics and Pediatric Dentistry 2
Pulp therapy for a carious primary molar with a normal radiograph and no spontaneous pain, but mechanical pulp exposure, is best treated by: