Orthodontic #7 – Unidontia

1. A patient, when in full intercuspation, shows a right side posterior crossbite and a lower midline that is deviated to the right. At initial contact there are bilateral posterior crossbites and coincident midlines. The most likely cause of this finding is

true unilateral crossbite.

occlusal interference and functional shift.

two ideal occlusions.

severe temporomandibular dysfunction.

2. Frontal cephalogram is used to evaluate which type of malrelation:

Facial asymmetry

Overbite

Overjet

Sn-GoGn angle

3. Maxillary skeletal arch expansion

is easiest in the preadolescent patient.

decreases arch space.

increases overbite.

requires surgery in skeletally immature patients.

4. Stationary anchorage in orthodontics means:

Equal and opposite movement in anchor unit

Use of opposite arch for anchorage

Abutment is not free to tilt

The abutment tooth is free to tilt

5. Which type of malocclusion should be corrected as early as possible?

Anterior open bite associated with a lip or digit sucking habit.

Cross-bite associated with a functional shift of the mandible from initial contact to maximum intercuspation.

Class II Division 2 associated with an increased anterior overbite.

Class II Division 1 associated with an anterior open bite.

6. In a mouth breather, tonicity of upper lip is

Increased

No change

Slightly affected

Decreased

7. The most appropriate time for surgical treatment of a patient with mandibular prognathism is

just after the end of the prepubertal growth spurt.

just after eruption of the second permanent molars.

following the completion of growth.

just before eruption of the second permanent molars.

8. Interceptive orthodontic treatment using appliances to treat the effects of oral habits should

occur during the early to middle mixed dentition.

start at the same time as comprehensive orthodontic treatment.

start in the primary dentition.

be delayed until the completion of growth

9. Areas of isolated gingival recession are most frequently seen on teeth that are

nonvital.

labially prominent in the arch.

moderately mobile.

ankylosed.

10. Incisal liability in the maxillary and mandibular arch is:

5 mm maxilla, 7 mm mandible

7 mm maxilla, 5 mm mandible

4 mm maxilla, 6 mm mandible

6 mm maxilla, 4 mm mandible

11. Ulnar sesamoid bone calcification starts in

Birth

Puberty

Prepubertal growth spurt

3 months after birth

12. In Downs analysis, an increase in Y axis is suggestive of:

Horizontal growth pattern

Skeletal dysplasia

Vertical growth pattern

Average growth pattern

13. Which condition is appropriately treated at an early age?

two deciduous molars nearly in crossbite

mild crowding of lower permanent incisors

deviated midline in the absence of a functional shift

posterior crossbite with a functional shift

14. Mesioangular ectopic eruption of a permanent mandibular first molar causing resorption of distal surfaces of the roots of the primary 2nd molar should be treated by:

Removing the soft tissue overlying the occlusal surface of permanent molar

Extracting the primary second molar

Disking of the distal surface of the primary second molar

Use of a brass wire to move the permanent molar distally

15. Adolescent age group is defined as:

14-20 years

10-14 years

6 – 10 years

10-18 years

16. The most appropriate treatment following the extraction of a first primary molar in a 4 year old child is

extraction of the contra-lateral molar.

to perform space analysis.

regular assessment of arch development.

insertion of a space maintainer.

17. In a case with Class II malocclusion in a growing child, why is deep bite corrected before overjet:

To achieve faster tooth movement

To reduce palatal trauma due to traumatic deep bite

To remove mechanical obstruction in normal mandibular anterior shift

To aid in bonding brackets to lower anterior teeth

18. The importance of proximal caries in deciduous 1st Molar for an orthodontist is:

Loss of arch length

RedUcticin in, arch length due to growth of mandible

Class I Occlusion

Flush terminal plane malocclusion

19. An Angle Class II, division 1 malocclusion can be differentiated from an Angle Class II, division 2 malocclusion based upon the

inclination of maxillary incisors.

severity of the Angle Class II malocclusion.

molar relationship.

amount of overbite.

20. Which of the following Class II Division 1 malocclusion(s) is/are most likely to be corrected with a cervical headgear?

Prognathic maxilla, decreased lower face height, increased over bite.

Open bite, prognathic maxilla, prognathic mandible.

Increased lower anterior face height, prognathic mandible, retrognathic maxilla.

Retrognathic mandible, retrognathic maxilla, open bite.

Question 1 of 20