Orthodontics Practice Questions
Orthodontics is a large branch with many named concepts, classifications and growth landmarks. This set covers growth and development, orthodontic diagnosis, treatment planning, biomechanics, appliances, interceptive orthodontics, the orthodontic-surgical interface, periodontal and TMD considerations, retention and relapse, and root resorption and other complications. General dentists are not expected to be orthodontists, but the AFK, INBDE, ORE and ADC do expect you to recognise malocclusions, know when interceptive treatment helps, understand basic force systems, and refer at the right time.
10 questions · answers and explanations revealed as you go · no sign-up
Questions
Question 1 of 10
Retention & Relapse
Why is relapse risk often elevated soon after appliance removal?
The answer is C.
After active tooth movement, periodontal ligament and gingival fiber systems need time to reorganize, and newly remodeled bone and occlusion may not yet provide full stability. This creates early relapse potential. Bone does not disappear, teeth do not routinely ankylose, and growth does not stop at debonding.
Question 2 of 10
Orthodontic-Surgical Interface
What is the purpose of postsurgical orthodontic finishing?
The answer is A.
After jaw repositioning and initial healing, orthodontic finishing refines intercuspation, tooth positions, arch coordination, and settling within the surgical plan. It is not intended to reverse skeletal correction or induce ankylosis. Retention is planned after active treatment rather than abandoned during healing.
Question 3 of 10
Root Resorption & Orthodontic Complications
Which force characteristic increases root-resorption risk?
The answer is A.
Heavy and prolonged orthodontic loading can increase periodontal injury and the risk or severity of inflammatory root resorption. Risk also depends on movement, duration, anatomy, and susceptibility. Light controlled mechanics and pauses after detected progression are risk-reduction strategies rather than guarantees.
Question 4 of 10
Appliances
What type of orthodontic appliance is an activator?
The answer is B.
The activator is a removable functional appliance that positions the mandible and alters the functional environment during growth. It generally requires substantial patient cooperation and is often worn for extended periods. It is not a surgical plate, periodontal barrier membrane, or instrument for root canal preparation.
Question 5 of 10
Orthodontics & Periodontal/TMD Considerations
How should an isolated painless temporomandibular joint click usually be interpreted?
The answer is B.
A reproducible painless click without locking or functional limitation is common and may need documentation and observation rather than treatment. Change in symptoms warrants reassessment. A click alone does not prove destructive disease, mandate surgery, or automatically contraindicate orthodontic care.
Question 6 of 10
Treatment Planning
Which strategy can create limited space without extracting a permanent tooth?
The answer is A.
Selected cases may gain limited space through arch development, molar distalization, proclination within periodontal limits, or carefully controlled interproximal enamel reduction. Choice depends on diagnosis and stability. Untreated disease, deliberate narrowing, and passive brackets do not provide a sound space-management strategy.
Question 7 of 10
Growth & Development
During orthodontic diagnostic records collection, what is the key purpose of obtaining dental study models (or digital scans)?
The answer is B.
Study models or digital scans provide three-dimensional records of the dentition allowing measurement of arch length, arch width, tooth size, crowding/spacing, overjet, overbite, and the occlusal relationship. Bolton analysis (tooth size discrepancy) is also performed on models.
Question 8 of 10
Orthodontic Diagnosis
A cephalometric analysis of a 12-year-old male patient with an Angle Class II malocclusion reveals an SNA angle of 88 degrees (normal = 82 degrees) and an SNB angle of 80 degrees (normal = 80 degrees). Which of the following is the correct diagnosis for this skeletal discrepancy?
The answer is A.
The SNA angle measures the position of the maxilla relative to the anterior cranial base. An increased SNA angle (88 vs norm of 82) indicates maxillary prognathism.
Question 9 of 10
Orthodontic Treatment Biomechanics
Which orthodontic archwire delivers a light continuous force over a large range of activation?
The answer is D.
Nickel-titanium archwires have superelastic properties that deliver a relatively light, continuous force over a wide range of activation, making them ideal for initial alignment of severely displaced teeth.
Question 10 of 10
Interceptive Orthodontics
What may accompany a unilateral posterior crossbite in a child?
The answer is B.
A narrow maxillary arch can cause premature contacts that deflect the mandible laterally into maximum intercuspation, creating an apparent unilateral crossbite and midline shift. Identifying the centric relation–intercuspation discrepancy guides treatment. Root fusion and universal canine loss are unrelated.
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