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100+ Free ABOMR Practice Questions

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Rectangular collimation compared with round collimation reduces patient effective dose by approximately:

A
B
C
D
to track
2026 Statistics

Key Facts: ABOMR Exam

Multi-day

Part 1 CBT

ABOMR

ACBOMR 2026

Transitioning To

Board name change

2.5 mm Al

FDA Filtration >70 kVp

Federal requirement

3 yrs

OMFR Residency

Application requirement

ABOMR is the OMFR specialty board (NCRDSCB recognition withdrawn; transitioning to ACBOMR 2026). Part 1 multi-day CBT MCQ. Master x-ray production (bremsstrahlung + characteristic), HVL filtration (2.5 mm Al >70 kVp), CBCT FOV selection, OKC/dentigerous/ameloblastoma radiographic patterns, MRONJ criteria, TMJ MRI dynamic imaging, and ALARA dose reduction.

Sample ABOMR Practice Questions

Try these sample questions to test your ABOMR exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1Which interaction in the x-ray tube target is primarily responsible for the continuous portion of the dental x-ray spectrum?
A.Bremsstrahlung interactions
B.Characteristic radiation
C.Compton scattering
D.Photoelectric absorption
Explanation: Bremsstrahlung ('braking radiation') occurs when high-speed electrons decelerate near tungsten nuclei, releasing photons of varying energies that produce the continuous (polyenergetic) portion of the spectrum.
2Increasing kVp in a dental x-ray exposure primarily affects which beam characteristic?
A.Quantity of photons produced
B.Penetrating ability (quality) of the beam
C.Focal spot size
D.Source-to-skin distance
Explanation: kVp determines the maximum photon energy and therefore the penetrating ability (quality) of the beam. Higher kVp yields more penetrating, lower-contrast images.
3At dental kVps above 70, which photon-tissue interaction predominates and is responsible for most scattered radiation?
A.Photoelectric absorption
B.Coherent (classical) scattering
C.Compton scattering
D.Pair production
Explanation: Compton scattering predominates above approximately 70 kVp in soft tissue. It produces scattered photons that degrade image contrast and are the principal radiation safety concern.
4FDA-required minimum total aluminum filtration for a dental x-ray unit operating above 70 kVp is:
A.0.5 mm Al equivalent
B.1.5 mm Al equivalent
C.2.5 mm Al equivalent
D.3.5 mm Al equivalent
Explanation: FDA mandates 2.5 mm Al equivalent total filtration for tubes operated above 70 kVp to remove low-energy photons that would otherwise contribute only to skin dose without reaching the receptor.
5If the source-to-receptor distance is doubled, the radiation intensity at the receptor will be:
A.Doubled
B.Halved
C.Reduced to one-fourth
D.Reduced to one-eighth
Explanation: By the inverse square law, intensity is inversely proportional to the square of the distance. Doubling distance reduces intensity to (1/2)^2 = 1/4 of the original.
6Switching from D-speed (Ultraspeed) to F-speed (Insight) film produces approximately what reduction in patient dose?
A.10%
B.25%
C.50%
D.75%
Explanation: F-speed film requires roughly half the exposure of D-speed film, yielding approximately a 50% reduction in patient dose with comparable diagnostic quality.
7The unit of effective dose, accounting for radiation type and tissue radiosensitivity, is:
A.Gray (Gy)
B.Sievert (Sv)
C.Roentgen (R)
D.Becquerel (Bq)
Explanation: Sievert (Sv) measures effective dose, weighting absorbed dose by radiation type (wR) and tissue sensitivity (wT) so different exposures can be compared on equal biological footing.
8Approximate effective dose for a digital full-mouth radiographic series (FMX) using rectangular collimation is closest to:
A.5 µSv
B.30 µSv
C.150 µSv
D.1000 µSv
Explanation: A digital FMX with rectangular collimation delivers approximately 150 µSv effective dose. Round PIDs and film receptors substantially increase this.
9Which biological effect is best described as STOCHASTIC and follows a linear no-threshold (LNT) model in radiation protection?
A.Radiation-induced cataract
B.Skin erythema
C.Radiation-induced cancer
D.Acute radiation syndrome
Explanation: Radiation-induced cancer (and heritable effects) is stochastic — probability increases with dose with no defined threshold (LNT model). Severity is independent of dose.
10Compared with adults, children are more radiosensitive primarily because:
A.They have thinner cortical bone
B.Their tissues contain more water
C.Cells are dividing more rapidly and they have a longer life expectancy for stochastic effect expression
D.Their tubehead settings cannot be adjusted
Explanation: Pediatric radiosensitivity reflects rapidly proliferating tissues (high mitotic activity) and longer post-exposure lifespan during which stochastic effects (cancer) can manifest.

About the ABOMR Exam

ABOMR Diplomate certification for Oral and Maxillofacial Radiology specialists — board still administering Diplomate exams (transitioning to ACBOMR in 2026); NCRDSCB recognition was withdrawn but the credential remains active for OMFR residency-trained dentists. Two-part exam: Part 1 multi-day CBT MCQ; Part 2 MCQ + short answer with radiographic interpretation. Covers radiation physics + biology, radiologic anatomy, intra/extraoral techniques, CBCT and 3D imaging, radiographic pathology, systemic imaging (TMJ MRI, sialography), and radiation protection.

Questions

100 scored questions

Time Limit

Multi-day (per ABOMR)

Passing Score

Per ABOMR (sectional pass/fail)

Exam Fee

Per ABOMR (ABOMR (transitioning to ACBOMR 2026))

ABOMR Exam Content Outline

20%

CBCT & 3D Imaging

CBCT principles, FOV selection, artifacts, MSCT vs CBCT, indications/limitations

20%

Radiographic Pathology

OKC, dentigerous, periapical cysts, ameloblastoma, OFD, osteomyelitis, MRONJ

15%

Radiation Physics & Biology

Bremsstrahlung, HVL filtration, photoelectric vs Compton, deterministic/stochastic effects

15%

Radiologic Anatomy

Mental foramen, IAN canal, max sinus, TMJ, CBCT anatomy landmarks

15%

Intra/Extraoral Techniques

Paralleling vs bisecting, BWX, PA, pano, ceph, occlusal, technique errors

10%

Systemic & Adjunct Imaging

TMJ MRI, sialography, salivary gland imaging, head/neck MRI/CT basics

5%

Radiation Protection & Regulation

ALARA, ICRP, NCRP, FDA, CDC, dose limits

How to Pass the ABOMR Exam

What You Need to Know

  • Passing score: Per ABOMR (sectional pass/fail)
  • Exam length: 100 questions
  • Time limit: Multi-day (per ABOMR)
  • Exam fee: Per ABOMR

Keys to Passing

  • Complete 500+ practice questions
  • Score 80%+ consistently before scheduling
  • Focus on highest-weighted sections
  • Use our AI tutor for tough concepts

ABOMR Study Tips from Top Performers

1Master x-ray physics: bremsstrahlung (continuous) + characteristic; kVp = penetration, mA × time = quantity
2Memorize FDA filtration: 0.5 mm Al ≤50 kVp / 1.5 mm 51-70 / 2.5 mm >70 kVp
3Drill CBCT FOV selection: smallest that captures ROI; document rationale; ALARA
4Know cyst/tumor radiographic patterns: OKC (axial expansion, minimal perforation, high recurrence) vs dentigerous (pericoronal at CEJ) vs ameloblastoma (multilocular soap bubble)
5Apply ALARA: lead apron + thyroid collar (intraoral; lead apron only for pano), fastest receptor, rectangular collimation, long PID

Frequently Asked Questions

What is the FDA minimum aluminum filtration requirement?

FDA-required total aluminum filtration in dental x-ray tubes: 0.5 mm Al for ≤50 kVp; 1.5 mm Al for 51-70 kVp; 2.5 mm Al for >70 kVp. Filtration removes low-energy x-rays that would be absorbed by patient skin without contributing to image — reduces patient dose without reducing diagnostic quality. Total filtration = inherent (tube + collimator) + added (Al disc).

How do you select CBCT field of view (FOV)?

CBCT FOV selection follows ALARA: use the SMALLEST FOV that captures the region of interest. Small FOV (5×5 cm) — single endo case, single tooth analysis. Medium FOV (8×8 cm) — implant planning quadrant or sextant. Large FOV (16×8 cm or larger) — full max + mand, TMJ bilateral, orthognathic planning, multiple impactions. Larger FOV = higher dose to patient. Document FOV selection rationale.

What distinguishes an OKC from a dentigerous cyst radiographically?

Dentigerous cyst: pericoronal radiolucency surrounding the CROWN of an unerupted tooth, attached at CEJ; most often max canine, mand 3rd molar; corticated borders, expansion. OKC (Odontogenic Keratocyst, now KCOT in older terminology): unilocular OR multilocular radiolucency, may be pericoronal but typically mandibular ramus; expands ALONG the bone axis (anteroposterior > buccolingual) with minimal cortical perforation; high recurrence rate (~30%); associated with PTCH gene mutations in Gorlin syndrome (NBCCS) when multiple.

How should I study for ABOMR Part 1?

Plan 500-1,000 hours over OMFR residency. Master White & Pharoah Oral Radiology: Principles and Interpretation (current edition) cover-to-cover — primary text. Read Mallya & Lam Diagnostic Imaging Oral & Maxillofacial. Study CBCT physics + artifacts (Scarfe textbook). Build a personal radiographic pathology image library: 100+ each of OKC, dentigerous, ameloblastoma, periapical, MRONJ, osteomyelitis. Case logs and publications required for board application.