Diagnosis practice questions for the periodontics Qualifying Exam
Diagnosis is where the 2017 classification is tested hardest. Expect charts and histories that ask for the stage, grade or case definition, and findings from radiographs, CBCT, labs and vital signs that change what you do next.
2027 ABP blueprint domain: Diagnosis
14%of our mock exams
~28of 200 full-length mock questions
126questions on this domain in the bank
What the blueprint covers
The 2027 Qualifying Exam blueprint lists these objectives for this domain:
Interpreting medical, dental and social history, vital signs, lab values and medical consultations
Extra-oral and intra-oral examination, including oral cancer screening and TMD analysis
Interpreting 2-dimensional radiographs and 3-dimensional imaging
Evaluating teeth, restorations, implants, oral hygiene and occlusion
Risk assessment, caries risk and pulp vitality, and the limits of microbial and host-marker tests
Diagnosis with the classification of periodontal and peri-implant diseases and conditions
High-yield areas
Staging by interdental CAL, radiographic bone loss, tooth loss and complexity factors
Grading by bone loss over age, and the smoking and HbA1c modifiers
Periodontitis case definition versus gingivitis on a reduced periodontium
Peri-implant health, mucositis and peri-implantitis when baseline radiographs are missing
Cairo recession types, endo-periodontal lesions and primary versus secondary occlusal trauma
How to study it
Stage and grade every chart you see, out loud, until the decision rules are automatic. Then practice the edge cases: missing baseline radiographs, a single tooth that changes the stage, and a patient whose HbA1c or smoking shifts the grade.
Free practice questions: Diagnosis
4 questions from the bank, with the full rationale and source. Pick your answer, then open the rationale.
Question 1 of 4 · hardDiagnosis
A 61-year-old woman has completed periodontal therapy. Her maxillary central incisors have about 50% radiographic bone loss, healthy gingiva and probing depths of 3 mm. Which additional finding would best indicate that these teeth have secondary occlusal trauma?
Stable mobility unchanged over 1 year
Bone loss that has not changed since therapy
Wedge-shaped cervical lesions on both teeth
Mobility that increases between visits
Facial gingival recession of 2 mm on both teeth
Show answer and rationale
Answer: D. Mobility that increases between visits
A (incorrect): Reduced support with stable, nonprogressive mobility is an adapted state. It does not by itself establish secondary occlusal trauma.
B (incorrect): Stable bone levels reflect reduced but stable support, not injury. Without progressive mobility, reduced support alone does not indicate occlusal trauma.
C (incorrect): There is no credible evidence that traumatic occlusal forces cause non-carious cervical lesions, so these lesions do not indicate occlusal trauma. They point to another cause.
D (correct): A reduced periodontium is meaningful for secondary occlusal trauma only when mobility is progressive, showing that the forces exceed the adaptive capacity of the site. Progressive mobility may come with migration and pain on function, and splinting may be needed for comfort.
E (incorrect): Observational evidence indicates that occlusal forces do not cause gingival recession. Recession is not a sign of occlusal trauma.
Source: Jepsen S, Caton JG, Albandar JM, et al. Periodontal manifestations of systemic diseases and developmental and acquired conditions: Consensus report of workgroup 3 of the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions. J Clin Periodontol. 2018;45(Suppl 20):S219-S229. Occlusal Trauma and Traumatic Occlusal Forces: Should we still distinguish primary from secondary occlusal trauma. https://doi.org/10.1111/jcpe.12951
Question 2 of 4 · easyDiagnosis
A mandibular first molar (#30) has a furcation through which a probe passes from buccal to lingual. Gingival recession has exposed the furcation entrance, so the furcation can be seen clearly without probing. Using the Glickman classification, how should this furcation be recorded?
Glickman grade I
Glickman grade II
Glickman grade III
Glickman grade IV
Hamp degree II
Show answer and rationale
Answer: D. Glickman grade IV
A (incorrect): Grade I is an incipient lesion with a suprabony pocket and slight bone loss in the furcation. This furcation is through-and-through, which is far beyond grade I.
B (incorrect): Grade II involves loss of interradicular bone and pocket formation, but a portion of the alveolar bone and PDL remains intact. This furcation is through-and-through.
C (incorrect): Grade III is a through-and-through lesion whose entrance remains covered by soft tissue. This furcation is visible because of recession.
D (correct): Grade IV is a through-and-through lesion with gingival recession, leaving the furcation clearly visible. Both features are present here.
E (incorrect): Hamp degree II is a horizontal loss of more than 3 mm without through-and-through involvement. This lesion passes through, and the question asks for the Glickman grade.
Source: Pilloni A, Rojas MA. Furcation involvement classification: a comprehensive review and a new system proposal. Dent J (Basel). 2018;6(3):34. Table 1, Review of classifications of furcation involvement (Glickman). https://pmc.ncbi.nlm.nih.gov/articles/PMC6162379/
Question 3 of 4 · moderateDiagnosis
At a new-patient examination 6 weeks ago, a 52-year-old man who smokes had a 10 mm homogeneous white patch on the left lateral border of the tongue that did not wipe off. A sharp cusp on the adjacent molar was smoothed at that visit. Today the lesion is unchanged in size and appearance. Which is the most appropriate next step?
Perform brush cytology and biopsy only if the result is positive
Use autofluorescence imaging to decide whether a biopsy is needed
Biopsy the lesion, or refer him to a clinician who will
Re-examine the lesion in 6 months to check for change
Send a salivary biomarker test before deciding on biopsy
Show answer and rationale
Answer: C. Biopsy the lesion, or refer him to a clinician who will
A (incorrect): Cytologic adjuncts are not recommended for evaluating these lesions. Cytology is reserved for patients who decline biopsy or referral, and a negative result would still require follow-up.
B (incorrect): Autofluorescence, tissue reflectance and vital staining are not recommended for evaluating potentially malignant disorders. Their accuracy is too poor to triage a persistent lesion.
C (correct): When a lesion has not resolved after follow-up and a potentially malignant disorder cannot be ruled out, the clinician should biopsy it or refer the patient. The lateral tongue is a high-risk site, and smoking adds concern.
D (incorrect): Periodic follow-up is for seemingly innocuous lesions. Once the lesion persists after the likely cause has been removed, further waiting delays a possible diagnosis of dysplasia or carcinoma.
E (incorrect): Commercially available salivary adjuncts are not recommended and should be used only in research. They cannot replace histologic diagnosis.
Source: Lingen MW, Abt E, Agrawal N, et al. Evidence-based clinical practice guideline for the evaluation of potentially malignant disorders in the oral cavity: A report of the American Dental Association. J Am Dent Assoc. 2017;148(10):712-727. Table 3, Recommendations 1, 2 and 4; definitions of seemingly innocuous and suspicious lesions. https://jada.ada.org/article/S0002-8177(17)30701-8/fulltext
Question 4 of 4 · easyDiagnosis
A 30-year-old woman reports aching in both cheeks that worsens with chewing. On the DC/TMD examination, palpation reproduces her familiar pain. To confirm a diagnosis of myalgia, which muscles must be examined?
Lateral and medial pterygoid
Masseter and sternocleidomastoid
Digastric and masseter
Temporalis and both pterygoids
Temporalis and masseter
Show answer and rationale
Answer: E. Temporalis and masseter
A (incorrect): The DC/TMD myalgia diagnosis does not rest on the pterygoids; the lateral pterygoid area is only a supplemental site. Familiar pain must be found in the temporalis or masseter.
B (incorrect): The sternocleidomastoid is a cervical muscle. Pain there may suggest a cervical or widespread pain disorder rather than masticatory myalgia.
C (incorrect): The digastric is not part of the required myalgia examination. The diagnosis rests on the temporalis and masseter.
D (incorrect): Only the temporalis and masseter are required, and this choice omits the masseter. Pterygoid findings are not part of the required examination.
E (correct): Myalgia under the DC/TMD requires familiar pain in the temporalis or masseter on palpation or on maximum opening, together with a history of pain modified by jaw function. Other muscles are not required for the diagnosis.
Source: Schiffman E, Ohrbach R, Truelove E, et al. Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) for Clinical and Research Applications: recommendations of the International RDC/TMD Consortium Network and Orofacial Pain Special Interest Group. J Oral Facial Pain Headache. 2014;28(1):6-27. Table 3, Myalgia diagnostic criteria; Examination protocol. https://pmc.ncbi.nlm.nih.gov/articles/PMC4478082/
For exam preparation only, not clinical advice.
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