Paediatric Dental Radiography and Radiology — Clinical Decision Framework
Overview and Learning Outcomes
This document summarises principles and practical guidance for paediatric dental radiography, emphasising how radiographic decisions differ from adults. It focuses on choosing the right image at the right time for the right child, balancing diagnostic need with radiation protection.
By the end of this document you should be able to:
- Justify why a particular radiograph is indicated.
- Recognise when radiographs are not indicated.
- Select the most appropriate imaging modality for the clinical question and individual child.
- Apply a consistent, patient-specific framework for radiographic decision making.
Key Concepts: Why Children Are Different
- Children are more radiosensitive than adults and have a longer lifetime for potential radiation effects to manifest; radiation decisions require greater justification.
- Developing dentitions (primary, mixed, erupting permanent teeth and tooth germs) complicate interpretation.
- Primary teeth have thinner enamel/dentin and broad contacts, so caries and infection often progress faster and may be hidden clinically.
- Children tolerate discomfort and intramural devices less well; failed positioning increases risk of repeat exposures and cumulative dose.
- Behaviour/cooperation influence what is technically achievable; aim for diagnostically adequate images rather than perfect ones.
Radiation Protection Frameworks
- ALARA — As Low As Reasonably Achievable: minimise dose.
- LADA — As Low As Diagnostically Acceptable: dose must produce a diagnostic image.
- Extension for paediatrics (abbreviated during the lecture): as low as diagnostically acceptable, indication-oriented, and patient-specific (referred here as ALADIPE). Core idea: radiographic decisions are indication-driven and tailored to the child.
Practical implications:
- Justify every radiograph with a clear clinical question.
- Choose the smallest exposure that answers the question.
- Tailor exposure and technique to the child’s size and behaviour.
- Accept diagnostically adequate images to avoid unnecessary repeats.
- Document indication and how findings influence management.
Decision-Making Checklist (Ask BEFORE any radiograph)
- What am I trying to diagnose?
- Will this image change management?
- Is there a lower-dose alternative that would answer the question?
- Can I realistically obtain a diagnostic image today with this child?
If answers are unclear or negative, the radiograph is likely not justified.
Common Radiographic Modalities — Roles, Advantages, Limitations
| Modality | Primary indications | Advantages | Limitations / Cautions |
|---|---|---|---|
| Bitewings (horizontal) | Interproximal caries detection, lesion monitoring, restorations, pulp status in primary molars | Sensitive for proximal caries posteriorly; low dose | Underestimates early clues; not needed if open contacts, low caries risk, recent films, or teeth near exfoliation |
| Vertical bitewings | Developing premolars, view of periapical/furcation regions in primary molars, limited closure | Helpful when child cannot fully close; extends periapical view | Technique sensitive |
| Periapicals (PA) | Trauma, periapical pathology (esp. permanent teeth), root morphology, endodontics | Problem-focused, useful for root fractures, working length | Not screening; can be hard to tolerate in young children |
| Occlusal (maxillary/mandibular) | Localisation of supernumerary/unerupted teeth, anterior trauma, large anterior field with single exposure | Large field with one intraoral exposure; often better tolerated than multiple PAs | Technique and angulation critical; size 4 or size 2 for small mouths |
| Panoramic (OPG) | Overview of dental development, eruption patterns, impacted/posterior supernumeraries, pre-op assessments | Broad overview, typically easier for children | Low sensitivity for anterior caries; distortion, magnification, movement artefact; not a replacement for intraoral images |
| Cone Beam CT (CBCT) | Localisation of impacted/supernumerary teeth, complex root resorption, complex trauma, surgical planning | 3D detail that may change management | Higher dose; use smallest FOV necessary; strict justification and reporting requirements (jurisdictional) |
Bitewing Radiography: Practical Guidance
- Primary role: detect interproximal caries (especially lesions beyond enamel); monitor progression and restorations.
- Indications: clinical suspicion of proximal caries, lesions not visualised clinically, or when management would change.
- When NOT to take: open contacts, low caries risk/no clinical concerns, recent radiographs, newly erupted or soon-to-exfoliate teeth, or when image would not change management.
Technique and practical tips:
- Film/sensor size: size 0 for most children (better tolerated than size 1/2).
- Holders: paediatric-friendly holders reduce cone cutting and repeats (red rim holders, QuickBite). If holders intolerable: use foam or paper tabs adhesive to phosphor plate covering.
- Patient positioning: seated upright, occlusal plane parallel to the floor, head stabilized.
- Bite: ask child to bite down slowly (not snap); consider demonstrating and practising without film.
- Behaviour management: tell-show-do, let child inspect sensor/camera, use simple instructions (“still as a statue”), countdown technique (press exposure at “2” to avoid last-second movement).
- Tube angulation: slight downward vertical angulation (approx. 5–8° relative to occlusal plane); tube often positioned more anteriorly than adult bitewings.
- Special anatomies: high narrow palate — position film closer to midline; seat film against palate and ask slow closure rather than lateral insertion.
Vertical Bitewings
- Useful when a child cannot tolerate or maintain firm closure for horizontal bitewings.
- Permit the child to be slightly open while still visualising contact points.
- Indications: young children, poor cooperation, viewing developing premolars, alveolar bone level assessment, and furcation/focal pathology in primary molars.
Occlusal Radiographs (Maxillary and Mandibular)
- High-value but underused in paediatrics: give a large field from a single intraoral exposure; often better tolerated.
- Indications:
- Maxillary occlusal: locate mesiodens/supernumeraries, assess unerupted/impacted incisors/canines, anterior trauma, double teeth, position of successional teeth.
- Mandibular occlusal: localisation of unerupted mandibular incisors, supernumeraries, anterior caries/periapical pathology, trauma.
- Film: size 4 typically (size 2 for smaller mouths) — usually only half the film is inserted (posterior part over molars).
- Stabilisation: ask child to bite gently on film; consider taping a tongue depressor to the film if biting too hard; parents may assist holding (ensure child’s/parent’s fingers are not in the beam).
- Technique:
- Patient upright, occlusal plane parallel to the floor.
- Maxillary occlusal tube: angle ≈ 65° downward, positioned over bridge of nose. Aim for roots and unerupted teeth (not just crowns).
- Mandibular occlusal tube: angle ≈ 45° upward, aimed through the chin.
Periapical Radiographs (PA)
- Indications in children: dental trauma (root fractures, displacement), periapical pathology (more reliable in permanent teeth), root morphology, endodontics, and investigating anomalies.
- Trauma series: three anterior PAs from different horizontal angles plus a maxillary occlusal to identify root fractures.
- Technique: paralleling technique preferred but may not be tolerated; use appropriately sized film and holders (ring kits, snap-a-ray, or alternatives). If repeats required and diagnostic image cannot be obtained, consider different modality.
Panoramic Radiography (OPG)
- Strength: broad overview of growth, eruption patterns, missing/supernumerary teeth (esp. posterior), impacted teeth, gross pathology.
- Common use: assessing ectopic canines (palpation absent by 9–10 years), pre-operative overview prior to GA.
- Advantages: less intraoral discomfort, single small anterior bite.
- Limitations:
- Low sensitivity for caries (especially anterior).
- Narrow anterior focal trough; anterior teeth may be distorted or missing.
- Susceptible to movement artefact and positioning errors in children.
- Special notes: some OPG machines can perform extraoral bitewing-like images for posterior contacts when intraoral imaging is not tolerated — they are NOT equivalent to intraoral bitewings and do not show anterior teeth.
Cone Beam CT (CBCT)
- Provides 3D detail but with higher dose than 2D imaging.
- Indications in children (only when 3D information will change management):
- Precise localisation of impacted/supernumerary teeth close to adjacent roots.
- Complex trauma or root resorption assessment.
- Complex surgical or endodontic planning.
- Principles:
- Strict justification: only when necessary to change management.
- Use the smallest field-of-view (FOV) and lowest exposure settings consistent with the diagnostic task.
- Consider short exposure times and lower resolution settings for children who cannot remain still.
- Jurisdictional requirements: training and reporting may be mandatory (example: Western Australia requires recognised CBCT training and a radiologist report). Check local regulations.
- Avoid routine or indiscriminate use.
Timing and Frequency — No Routine Schedules; Individualised Care paedsradiographfrequency
- There is no set age to start radiographs and no justification for routine time-based schedules independent of clinical need.
- Timing must be linked to caries risk, dental development, behaviour, and whether imaging will change management.
- General guidance for bitewing intervals (examples; treat as flexible guides, not rules):
| Caries risk | Suggested bitewing interval |
|---|---|
| Low risk | Every 24–36 months |
| Moderate risk | Typically 12–24 months (individualise) |
| High / Extreme risk | Shorter intervals (e.g., 6–12 months) |
- Regular review and adjustment of intervals is required as risk status changes.
- Imaging used to: monitor initial lesions, detect new caries early when teeth are restorable, and assess response to preventive measures.
Clinical Case: Mesiodens in a 7-Year-Old — Imaging Pathway and Rationale
Summary of timeline and decisions:
-
Presentation (age 7): referred for orthodontic assessment with prior extensive dental treatment and extractions of primary molars.
- Imaging: OPG taken to assess overall growth, eruption status, unerupted teeth, and root development.
- Findings on OPG:
- Dental age consistent with chronological age.
- No third permanent molars visible.
- Early erupted premolars/teeth with short roots (consistent with previous extractions).
- Space loss and reduced spacing for maxillary canines.
- Inverted midline supernumerary (mesiodens) between 11 and 21 (labelled 11s), slight distal displacement of 11.
- Possible dens invaginatus (dental anomaly) noted on unerupted teeth 35 and 45.
- Decision: No immediate surgery; child’s central incisors have erupted and orthodontic treatment planned in ~2 years. Aim: localise the mesiodens with lower-dose imaging.
- Next image chosen: Maxillary occlusal radiograph (lower dose than CBCT), using vertical tube shift technique to determine buccal/palatal position.
-
Interpretation using tube-shift (SLOB) principle:
- SLOB rule: Same Lingual / Opposite Buccal — movement of object relative to reference when tube angulation changes indicates buccal vs palatal position.
- Observations between occlusal and OPG images:
- Incisal edge of mesiodens moved down relative to the reference (root apex of 11) when tube angulation changed in the same direction → indicates palatal position (slight palatal).
- Root tip position unchanged relative to CEJ → suggests root lies between 11 and 21 in same plane.
- Conclusion: occlusal + OPG provided sufficient localisation for monitoring.
-
Two years later (age 9): patient now scheduled for full fixed orthodontic treatment; orthodontic team requests removal of the mesiodens to allow space closure.
- Management changed from monitoring to surgical removal — clinical question now requires precise 3D localisation relative to adjacent roots and assessment of surgical risk.
- Imaging decision: Limited field-of-view CBCT justified for surgical planning and informed consent. Smallest FOV used; decision aligned with ALADIPE principles.
- Outcome: CBCT confirmed earlier localisation and provided necessary detail for safe surgical planning.
Clinical lessons from the case:
- Imaging escalation is driven by change in management. Initial low-dose imaging may be sufficient for monitoring.
- Use tube-shift techniques to localise teeth before escalating to CBCT when possible.
- CBCT is appropriate when 3D information will change management and when it reduces overall risk (e.g., reduces surgical risk).
Practical Behaviour Management Tips to Minimise Dose
- Tell-show-do: reduce anxiety and movement.
- Let child inspect sensor/camera; demonstrate placement.
- Stabilise head (headrest) and seat upright (occlusal plane parallel to floor).
- Ask for slow closure; practise without film first.
- Take highest-value image first in case cooperation deteriorates.
- Countdown technique: press exposure on “2” to avoid last-second movement.
- Avoid placing fingers between film and teeth; if parents assist, ensure fingers out of beam path.
Documentation and Legal Considerations
- Document indication for each radiograph and how findings influence treatment decisions.
- Record justification for not taking radiographs when relevant.
- For CBCT, document justification, FOV selection, and ensure scans are reported by appropriately qualified personnel where required by jurisdiction.
- Local regulations vary — check training/reporting requirements for CBCT and other modalities in your practice location.
Key Takeaways
- Justification first: every radiograph must answer a clear clinical question.
- Choose the simplest, lowest-dose image that will answer that question; escalate only when the information will change management.
- Tailor imaging to the individual child (size, behaviour) and accept diagnostically adequate images to avoid unnecessary repeats.
- Behaviour management is an effective dose-reduction tool (fewer repeats).
- No routine, time-based schedules — timing should be risk-based and individualised.
- Document clinical reasoning and how imaging influenced care — good documentation supports safe, defensible practice.
Recommended action: review basic radiography physics and clinical techniques (covered in prior units) and integrate those principles with the paediatric-specific guidance presented here for safe, evidence-based imaging in children.