DMD Orthodontics 3

Question 1

Which radiographic finding is the most reliable indicator of orthodontically induced external apical root resorption (EARR)?

Accepted Answer

Shortened root length with a blunted or pipette-shaped apex

Answer

Widening of the periodontal ligament space

Answer

Periapical radiolucency

Answer

Hypercementosis of the root surface

Question 2

The Tweed analysis uses a triangle formed by three cephalometric measurements. Which set of angles comprises the Tweed triangle?

Accepted Answer

FMA, FMIA, IMPA

Answer

SNA, SNB, ANB

Answer

SN-MP, ANB, SNB

Answer

ANB, IMPA, SNA

Question 3

Dental transposition is defined as which of the following tooth anomalies?

Accepted Answer

Positional interchange of two adjacent teeth occupying each other's normal position

Answer

Ectopic eruption of a tooth through an abnormal site

Answer

Formation of a supernumerary tooth in the arch

Answer

Delayed eruption of a permanent tooth beyond two standard deviations of the norm

Question 4

Anterior open bite malocclusion that develops during the mixed dentition is most commonly associated with which parafunctional habit?

Accepted Answer

Digit sucking (thumb/finger) or tongue thrusting

Answer

Bruxism (tooth grinding)

Answer

Mouth breathing without tongue thrust

Answer

Nail biting

Question 5

Which type of retainer provides the most stable long-term retention for lower anterior teeth after orthodontic alignment, reducing the risk of relapse?

Accepted Answer

Bonded fixed lingual retainer

Answer

Removable Hawley retainer

Answer

Thermoplastic (Essix/clear) retainer

Answer

Functional retainer

Question 6

In orthodontics, 'torque' most accurately refers to which type of tooth movement?

Accepted Answer

Root movement labially or lingually while controlling crown position

Answer

Rotation of a tooth around its long axis

Answer

Bodily mesiodistal translation of the entire tooth

Answer

Vertical intrusion or extrusion of a tooth

Question 7

For a skeletally mature adult patient with significant Class III malocclusion (mandibular prognathism), the most appropriate definitive surgical correction is:

Accepted Answer

Bilateral sagittal split osteotomy (BSSO) for mandibular setback

Answer

Maxillary Le Fort I advancement only

Answer

Rapid palatal expansion to correct the arch width discrepancy

Answer

Chin cup orthopedic therapy to restrain mandibular growth