NBDE Part II 5

Question 1

A 10-year-old patient has a pulp exposure on tooth #19 (mandibular first permanent molar) due to caries. The tooth is asymptomatic and radiographs show no periapical pathology. The treatment of choice is:

Accepted Answer

Pulpotomy with mineral trioxide aggregate (MTA)

Answer

MTA pulpotomy is the treatment of choice for carious pulp exposures in young permanent teeth with closed or open apices, providing the best success rates for vital pulp therapy.

Question 2

Which of the following describes the working width (apical enlargement) principle during root canal preparation?

Accepted Answer

The canal should be enlarged at least 3 ISO sizes larger than the first file to bind at the apex

Answer

Enlarging at least 3 ISO sizes beyond the initial apical binding file ensures adequate debridement and disinfection of the apical third.

Question 3

Which class of malocclusion is characterized by a mesially positioned mandibular first molar relative to the maxillary first molar?

Accepted Answer

Class III

Answer

Angle Class III malocclusion is defined by the mesiobuccal cusp of the maxillary first molar occluding posterior to the buccal groove of the mandibular first molar, indicating a mesial molar relationship.

Question 4

Which type of bone graft has both osteogenic and osteoinductive properties and is considered the gold standard in periodontal regeneration?

Accepted Answer

Autograft from the iliac crest or intraoral sites

Answer

Autografts contain living osteogenic cells and growth factors, providing osteogenesis, osteoinduction, and osteoconduction — the only graft with all three properties.

Question 5

A dentist notices an asymptomatic, well-defined unilocular radiolucency at the apex of a vital tooth #8. The MOST likely diagnosis is:

Accepted Answer

Nasopalatine duct cyst

Answer

The nasopalatine duct cyst appears as a heart-shaped or round radiolucency between the maxillary central incisors in a vital tooth and is the most common non-odontogenic cyst of the jaws.

NBDE - National Board Dental Examination Practice Test

NBDE - National Board Dental Examination Practice Test

NBDE Part II 5