Part 1: Evidence for Radiographic Examinations in Paediatric Dentistry
Paediatric dental care must be both effective and minimally invasive. This will be a 3-part practical series of posts on radiographs in children. In Part 1, we focus on the evidence supporting the use of intra-oral radiographs, while Part 2 will address the practical “how-to” of performing these radiographs in a child-friendly manner, and Part 3 will look at OPGs and CBCTs.
One of the more challenging parts of an examination on a child can be radiographs (x‑rays). Anecdotally, it is one of the poorer taught and practiced components of paediatric dentistry. Common misconceptions include “you do not need x‑rays on children” and “if they cannot tolerate it – that’s OK…”. In reality, radiographs are a critical diagnostic tool that support early detection of decay and proper treatment planning.
Where Does Decay Occur in Primary Teeth?
Decades of research and clinical experience have demonstrated that, in children, the majority of carious lesions develop on the interproximal surfaces of the teeth. Unlike occlusal decay—which can often be detected visually—early and moderate interproximal lesions are hidden between the teeth and may progress unnoticed during routine clinical examinations.
Exceptions: Enamel hypomineralisation can result in atypical breakdown and decay (e.g. occlusal and lingual surfaces of lower 2nd primary molars), but these cases remain the exception rather than the rule.
Why Are Intra-Oral Radiographs Important?
Usually, by the time you can see a carious lesion in the mouth, it has been present for several months or even years. Detecting these lesions early allows for preventive measures, such as improved oral hygiene, use of 1450 ppm toothpaste, flossing, and silver diamine fluoride (SDF) applications. This is particularly important in children, as invasive procedures can be challenging to perform effectively.
Failing to take intra-oral radiographs when a lesion is clinically suspected also diminishes your ability to treatment plan effectively. It is also MEDICO-LEGALLY indefensible to perform invasive dental procedures (fillings, pulpal treatments, and extractions) without a radiograph. We wouldn’t do this to adults, so why do we do it to kids? Often, it’s simply because it is harder!
When Should We First Take Bitewings or Occlusal Images?
There is limited evidence on this topic, with expert opinion guiding most recommendations. Risk factors must also be considered. For example, decay rates in Australian children are much higher (nearing 50%) compared to some European countries.
Bitewing Radiographs:
In general, if the interproximal spaces are closed, we will take the first set of bitewings at around 4 years of age (approximately 18–24 months after eruption of the 2nd primary molars). If no clinical issues are noted at this age, we may defer radiographs if the child struggles, but we emphasize to the child and parent that they will be obtained at the next visit.Occlusal Images:
Even with closed anterior contacts, interproximal decay can be detected easily clinically. As such, we do not recommend these for screening. More so, they are generally reserved for when decay is clinically evident, or for cases of trauma or suspected anomaly.
What About at Recalls?
The timing for repeat radiographs depends on your treatment plan, the child’s risk factors, and any active lesions. We created the below table which is what we do in our practice.
What About Other Imaging? Eg, OPGs and Bitewing Function
OPGs tend to have lower resolution and are primarily used for assessing dental development rather than detecting early carious lesions. With excessive overlap, they cannot accurately assess lesion depth, leading to inappropriate treatment if used in isolation - this includes with the Bitewing function. Essentially, OPGs are not a substitute for comprehensive intra-oral radiographic treatment planning.
ALARA: Minimizing Radiation Exposure
Adhering to the ALARA (As Low As Reasonably Achievable) principle is essential when working with paediatric patients. Here are several strategies to minimize radiation exposure without compromising diagnostic quality:
Rectangular Collimation:
Use rectangular collimation to narrow the x‑ray beam, thereby reducing scatter and minimizing the exposed area.Optimized Exposure Settings:
Adjust exposure times and settings according to the child’s size and age. Pediatric-specific protocols help reduce the radiation dose while maintaining image quality.Digital Radiography:
Digital radiography is what we should be using on children. Failure to use this completely fly’s in the face of ALARAShielding:
Many guidelines are recommending against lead aprons now, with the jury out on thyroid collars (as the beam does not commonly go near here and scatter can be ‘trapped’ by the collar. In our practice we do not use either.Proper Positioning and Technique:
Ensure accurate sensor or film placement to prevent the need for repeat exposures. A well-taken radiograph on the first attempt is key to minimizing overall radiation exposure.Regular Equipment Maintenance:
Keep radiographic equipment calibrated and maintained to ensure it operates at peak efficiency, thereby avoiding unnecessary radiation doses.
Children are many time more vulnerable to radiation exposure than us old adults. So we do need to be careful that we do the least number of x-rays we can. .
Conclusion and Next Steps
The evidence is clear: intra-oral radiographs, particularly bitewing images, are an indispensable tool in paediatric dentistry. With most decay occurring interproximally, early detection through radiographic examination not only enables timely preventive care but also supports appropriate treatment planning. In
Part 2 of this series, we will get to the practical stuff! - dtailing the step-by-step techniques and patient management strategies for performing radiographs in a child-friendly manner. And in Part 3, we will explore the roles of OPGs and CBCTs in paediatric dental imaging.
Stay tuned for the next installment, where theory meets practical application!