10 exam-style questions with answers and explanations, straight from our 1,030-question bank. Tap an answer to check yourself. When you're ready, take the scored version in the free practice test.
The Orthodontics exam has 240 questions and runs 5 hours.
These 10 free Orthodontics questions are organized by exam domain, so you can see how each part of the Certification in Orthodontics blueprint is tested. Reveal the answer and explanation under each question.
A lateral cephalogram obtained for treatment planning shows definite concavities along the inferior borders of C2, C3, and C4. The bodies of C3 and C4 are both horizontally rectangular: their widths exceed their posterior heights. In the six-stage cervical vertebral maturation method, these findings correspond to:
Correct answer: C - CS4, a circumpubertal maturation pattern
A 13-year-old referred for delayed eruption retains numerous primary teeth. Imaging reveals multiple supernumerary teeth and unerupted permanent successors. Medical records document hypoplastic clavicles and delayed closure of cranial sutures. Which disorder-gene pairing unifies the dental and skeletal findings?
Correct answer: A - Cleidocranial dysplasia - RUNX2
In an experimental tooth-movement study, increasing the continuous orthodontic load is followed by a lag in displacement rather than faster movement. Histology shows an acellular zone in the compressed periodontal ligament; osteoclasts are removing adjacent alveolar bone from its marrow-facing surface. Which tissue response explains this sequence?
Correct answer: C - Hyalinization followed by undermining resorption
At an orthodontic review, a 17-year-old mentions a reproducible right TMJ click on opening and closing. It has been present for several years. Opening is unrestricted, and there is no pain, locking, tenderness, or recent occlusal change. The patient asks whether braces must be stopped to protect the joint. What is the most appropriate response?
Correct answer: A - Document the finding, reassure the patient, and continue treatment with symptom monitoring
In a randomized split-mouth trial, each patient receives a fluoride-releasing bracket adhesive on one side and a conventional adhesive on the other. New white-spot lesions are recorded for each bonded tooth after 12 months. The investigators pool the teeth into two treatment groups and calculate confidence intervals as though every tooth came from a different patient. Which revision addresses the principal analytical error?
Correct answer: C - Account for the paired treatments and correlation among teeth within each patient
A prepubertal 8-year-old becomes unresponsive in the orthodontic office. Two trained healthcare rescuers are present, emergency services have been activated, and an AED is being brought. Despite effective bag-mask ventilation with oxygen, the child remains poorly perfused with a pulse of 48/min. No advanced airway is in place. Under the 2025 AHA/AAP pediatric resuscitation recommendations, which action is indicated now?
Correct answer: D - Begin CPR using 15 compressions followed by 2 breaths with both rescuers
An 8-year-old has a right posterior crossbite and a mandibular dental midline displaced to the right in maximum intercuspation. During guided closure, the midlines initially coincide and the posterior teeth meet cusp-to-cusp on both sides; the mandible then slides right into intercuspation. The maxillary arch is symmetrically narrow, and no persistent facial asymmetry is present. Which diagnosis best accounts for the apparently unilateral crossbite?
Correct answer: B - Bilateral maxillary transverse deficiency with a functional mandibular shift
An incisor with reduced but stable periodontal support is represented by a two-dimensional force model. A horizontal 0.8-N bracket force has a perpendicular lever arm of 12 mm about its center of resistance, producing a clockwise moment. An existing couple supplies 6.0 N·mm counterclockwise. No other orthodontic loads act. To obtain initial translation while preserving the 0.8-N force, which ADDITIONAL couple is required?
Correct answer: B - 3.6 N·mm counterclockwise
A patient has equally undersized maxillary lateral incisors. The six mandibular anterior teeth total 38.0 mm in mesiodistal width, and the six maxillary anterior teeth total 46.0 mm. A restorative setup will retain all mandibular widths and enlarge only the two maxillary lateral incisors, by equal amounts. Using an agreed target anterior Bolton ratio of 77.2%, approximately how much additional width should be reserved for EACH lateral incisor?
Correct answer: B - 1.6 mm per lateral incisor
A skeletally mature patient with a marked Class III jaw discrepancy has only a small reverse overjet because the upper incisors are proclined and the lower incisors are retroclined. Combined orthodontic-orthognathic treatment is planned, with sufficient alveolar space for decompensation. Which presurgical incisor change should the patient be prepared for?
Correct answer: A - Upper incisor retroclination and lower incisor proclination, increasing the reverse overjet
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