Fibro-osseous and bone disease · Oral Pathology
Bone & Jaw Pathology MCQ
Fibro-osseous lesions, giant cell lesions, Paget disease, osteomyelitis, osteoradionecrosis, and medication-related osteonecrosis of the jaw, plus the benign and malignant bone tumors. 25 MCQs and 8 INBDE patient cases.
25 practice MCQsQuick-reference tableMnemonics + clinical pearlsFull distractor explanations
High-yield review
Concept summary and clinical relevance.
Quick-reference structure first, then detailed coverage. Mnemonics in amber, clinical pearls in blue.
Beyond the teeth, the jawbones develop their own diseases: fibro-osseous and dysplastic lesions, giant cell and metabolic bone disease, infection, the drug- and radiation-related necrosis that dentistry must actively prevent, and benign and malignant tumors. The reading clues are age, the radiographic texture (ground-glass, cotton-wool, sunburst, onion-skin), whether the related teeth are vital (cemento-osseous dysplasia), and the warning signs (paresthesia, rapid growth) that flag malignancy. The single highest-value idea is prevention: make the patient dentally fit before antiresorptive therapy or head and neck radiation.
Bone and jaw conditions
| Condition | Feature | Clue |
|---|---|---|
| Fibrous dysplasia | Ground-glass bone, painless swelling | Young patient; may be part of McCune-Albright |
| Cemento-osseous dysplasia | Lesions at apices of VITAL teeth | Do not treat endodontically; teeth are vital |
| Paget disease | Cotton-wool bone, jaw enlargement | Older patient; elevated alkaline phosphatase |
| Osteomyelitis | Bone infection, sequestrum | Pain, swelling, often after extraction |
| ORN / MRONJ | Exposed necrotic bone | Prior radiation or antiresorptive drugs |
| Osteosarcoma | Sunburst, symmetric PDL widening | Most common primary bone malignancy |
Fibro-Osseous and Dysplastic Lesions
- Fibrous dysplasia is a fibro-osseous lesion of young patients: a painless, slowly enlarging, unilateral swelling with a ground-glass radiographic texture, caused by a GNAS mutation; the polyostotic form with cafe-au-lait spots and endocrine abnormalities is McCune-Albright syndrome.
- Ossifying fibroma is a well-demarcated benign neoplasm that, unlike the diffuse fibrous dysplasia, can be enucleated; the distinction matters for management.
- Cemento-osseous dysplasia occurs at the apices of teeth that are VITAL: the periapical type favors the anterior mandible, and the florid type is multiquadrant (often in middle-aged women), evolving from radiolucent to mixed to radiopaque.
- The key clinical trap is to recognize cemento-osseous dysplasia on vital teeth and leave it alone rather than mistaking it for periapical disease and starting unnecessary root canal treatment.
Clinical pearl, Vital teeth change everything in fibro-osseous disease
Periapical and florid cemento-osseous dysplasia sit at the apices of vital teeth, so the worst error is to read them as periapical pathology and perform endodontic treatment on healthy teeth. Pulp test first. These lesions are usually asymptomatic and need no treatment, though florid disease in dense bone raises the long-term risk of infection if it becomes exposed. Fibrous dysplasia is monitored or conservatively contoured, not aggressively resected, because it can regrow.
Giant Cell Lesions and Metabolic Bone Disease
- The central giant cell granuloma is an intraosseous radiolucency favoring the anterior mandible that can cross the midline; cherubism is a familial, bilateral giant cell process in children that gives a cherubic facial fullness.
- When a giant cell lesion is found, hyperparathyroidism must be excluded, because the brown tumor of hyperparathyroidism is histologically a giant cell lesion; check serum calcium and parathyroid hormone, and look for loss of the lamina dura.
- Paget disease of bone affects older patients with disorganized bone turnover: the jaw enlarges (a denture or hat no longer fits), the radiograph shows a cotton-wool pattern, alkaline phosphatase is elevated, and hypercementosis makes extractions difficult.
- Paget disease carries a small risk of transformation to osteosarcoma, so new pain or rapid change in a patient with Paget disease is taken seriously.
Clinical pearl, A giant cell lesion is a reason to check calcium
A central giant cell lesion of the jaw should prompt screening for hyperparathyroidism, because the brown tumor of hyperparathyroidism looks the same under the microscope. A simple serum calcium and parathyroid hormone (with the radiographic clue of lost lamina dura) can uncover a systemic cause. In Paget disease, the combination of an enlarging jaw, cotton-wool bone, and elevated alkaline phosphatase is the classic triad, and hypercementosis warns of difficult extractions.
Osteomyelitis, Osteoradionecrosis, and MRONJ
- Osteomyelitis of the jaw is a bone infection, more common in the mandible and often following an odontogenic infection or extraction; it presents with deep pain and swelling, and a sequestrum (a fragment of dead bone) may form. Treatment is drainage, removing the source, and antibiotics.
- Osteoradionecrosis is exposed, non-healing necrotic bone in a field of prior head and neck radiation, where the tissue is hypovascular, hypocellular, and hypoxic; extractions after radiation are the classic trigger.
- Medication-related osteonecrosis of the jaw (MRONJ) is exposed bone (or bone probed through a fistula) persisting over about eight weeks in a patient on antiresorptive (bisphosphonate, denosumab) or antiangiogenic therapy, without prior radiation; risk is higher with intravenous (cancer-dose) drugs and with extractions.
- For both ORN and MRONJ, prevention is far easier than treatment: complete needed extractions and make the patient dentally fit before radiation or antiresorptive therapy begins.
Clinical pearl, Prevention is the whole game for ORN and MRONJ
Before head and neck radiation or before antiresorptive therapy, the patient should be made dentally fit: extract hopeless teeth and complete invasive work first, then favor conservative, non-surgical care afterward. Once established, exposed necrotic bone is difficult to treat (ORN may involve hyperbaric oxygen; MRONJ is staged and often managed conservatively). The dental team's biggest contribution is the pre-treatment clearance that prevents these complications.
Bone Tumors: Benign to Malignant
- Tori (palatinus and mandibularis) and exostoses are benign bony outgrowths that need no treatment unless they interfere with a denture; an osteoma, especially when multiple, can signal Gardner syndrome (with intestinal polyposis and supernumerary teeth).
- Osteosarcoma is the most common primary malignancy of bone; in the jaws it can show a sunburst periosteal reaction and a symmetric widening of the periodontal ligament space around a tooth, often in younger patients.
- Ewing sarcoma (children, with an onion-skin periosteal reaction) and chondrosarcoma are other primary bone malignancies to recognize.
- Metastasis is actually the most common malignancy found in the jawbones (from breast, lung, prostate, kidney, and thyroid primaries), favoring the posterior mandible and sometimes causing numbness of the lip and chin (the numb chin sign).
Clinical pearl, Numbness and rapid change are red flags
New numbness of the lower lip and chin (the numb chin sign), unexplained tooth mobility, rapid swelling, or a symmetric widening of the periodontal ligament space are sinister and suggest malignancy (primary or metastatic) until proven otherwise. These warrant prompt imaging, biopsy, and referral, not watchful waiting. By contrast, tori and exostoses are benign and need attention only when they interfere with function or a prosthesis.
Core Recall Check
25 board-style MCQs.
Active recall is the highest-yield study method. Pick an answer, check it, and read why every distractor is wrong.
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Keys: A-E or 1-5, Enter to check
- Question 1ModerateA painless, slowly enlarging, unilateral jaw swelling with a ground-glass radiographic appearance in a young patient suggests:
- Question 2HardPolyostotic fibrous dysplasia with cafe-au-lait skin macules and endocrine abnormalities is:
- Question 3HardCompared with fibrous dysplasia, an ossifying fibroma is:
- Question 4HardMixed or radiopaque lesions at the apices of VITAL anterior mandibular teeth, found incidentally, most likely represent:
- Question 5ModerateThe most important management point for cemento-osseous dysplasia on vital teeth is to:
- Question 6ModerateA central giant cell granuloma most characteristically occurs in the:
- Question 7ModerateBilateral giant cell lesions of the jaws in a child, with a familial pattern and cherubic facial fullness, describe:
- Question 8HardWhen a central giant cell lesion of the jaw is identified, an important systemic condition to exclude is:
- Question 9ModerateAn older patient whose denture no longer fits, with cotton-wool bone on radiograph and an elevated alkaline phosphatase, most likely has:
- Question 10ModerateA recognized complication of Paget disease relevant to dentistry is:
- Question 11ModerateOsteomyelitis of the jaw is most common in the:
- Question 12ModerateA fragment of dead, separated bone within a focus of osteomyelitis is called a:
- Question 13ModerateInitial management of acute osteomyelitis of the jaw includes:
- Question 14ModerateOsteoradionecrosis develops in bone that has been:
- Question 15ModerateThe most effective way to reduce the risk of osteoradionecrosis is to:
- Question 16ModerateMedication-related osteonecrosis of the jaw (MRONJ) is most associated with which drug class?
- Question 17ModerateThe most effective strategy to prevent MRONJ is to:
- Question 18HardThe risk of MRONJ is generally highest in patients receiving:
- Question 19ModerateThe most common primary malignancy of bone, which in the jaws may show a sunburst pattern and symmetric widening of the periodontal ligament space, is:
- Question 20HardAn onion-skin periosteal reaction in a child's bone lesion is classically associated with:
- Question 21HardThe most common malignancy found within the jawbones overall is:
- Question 22HardNew numbness of the lower lip and chin (the numb chin sign) associated with a jaw lesion should raise concern for:
- Question 23EasyA bony hard, broad-based growth in the midline of the hard palate that is asymptomatic is most likely a:
- Question 24HardMultiple osteomas of the jaws, especially with supernumerary teeth, should prompt evaluation for:
- Question 25HardFocal sclerotic (radiopaque) bone at the apex of a tooth with chronic low-grade pulpal inflammation is termed:
Clinical Reasoning Cases
INBDE patient cases.
8 ADA INBDE-format patient cases on bone & jaw pathology. Each case is a shared patient box plus linked questions with full distractor explanations.
INBDE Patient Cases
Bone & Jaw Pathology INBDE Patient Cases →
8 patient cases · 40 linked questions
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Author
Dr. Isaac Sun, DDS
Founder, KYT Dental Services. These MCQs are reviewed by a practicing clinician and offered as an educational reference for dental students.
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