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If my X-rays are coming out too light or too dark, what can I tell my staff to do differently?

As much as traditional intraoral radiography has become a rudimentary part of the office standard operating procedure, it can be easy to forget that there are a ton of variables that can affect the diagnostic value of that PA or bitewing.

While we have found that different doctors have slightly different preferences when it comes to how they like to see their intraoral radiographs, one common question we get is very simply a preference to make the image lighter or darker. 

Sometimes, when the staff member asks about “brightness”, they may actually be referring to “contrast”, which is slightly different.  However, for this discussion, we will focus on simple brightness and darkness.

Understanding the Variables

If the staff understands the variables that cause the radiographs to be light or dark, it can empower them to make their own adjustments so as to provide the exact diagnostic information that the doctor is looking for.

To do this, it’s critical that your staff understand a fundamental correlation:

A dental radiograph that is too dark generally means that it was overexposed (i.e. too much radiation hitting the sensor).  A dental radiograph that is too light generally means that it was underexposed (i.e. too little radiation hitting the sensor).

The variables that can cause an underexposed or overexposed radiograph span from the size of the patient, the characteristics of the anatomy being captured (e.g. anterior vs posterior), the x-ray parameters and the technique.  Of course, this also assumes the equipment is functioning properly.

The obvious question then becomes: what adjustments can the staff make? 

Refining Technique

Technique is typically the first area to check if there has been a sudden change in the lightness or darkness of the radiograph (or if this seems to vary based on the operator).  For instance, lighter radiographs could be a result of the x-ray source being positioned slightly farther from the sensor.  Distance can have a large impact in the amount of radiation hitting the sensor, so positioning the x-ray source slightly farther from the patient’s cheek can result in a lighter radiograph. 

Keeping consistent distance can be an even bigger variable if a handheld x-ray sources is used because this device is held “free-hand” [see article about overlooked challenges of handheld].

Adjusting Parameters

If the technique is not the driver, then the operator can look to adjust the parameters of the x-ray sources.  The key parameters of most dental x-rays include the kvp (voltage), the mA (current) and the exposure time.  Increasing any of these will typically result in a darker radiograph.  On most dental x-rays, the parameter that is the easiest to adjust is the exposure time (typically in milliseconds).  Increasing the exposure time will typically result in a darker image.

So, therefore, one easy approach is:  if a darker radiograph is desired,  the staff can increase the exposure time setting on the x-ray.  If a lighter radiograph is desired, the staff can decrease the time setting on the x-ray.

Of course, this also assumes the staff is operating x-ray equipment within their specified ranges, and practicing ALARA principles.

Adjusting Filters

As with any digital imaging, software filters can also serve to adjust lightness and darkness.  Some common filters that will affect lightness and darkness include:  contrast, gamma, or brightness. 

It’s also worth noting that some software will auto-adjust the brightness.  Sometimes, if the sensor is significantly underexposed for any of the reasons mentioned above, instead of resulting in a light image, it may result in increased graininess.  This is due to the software trying to improve the image, when there is less information for the software to work with (due to lack of adequate radiation). It’s a little bit like zooming in on a low resolution image.

Conclusion

Achieving optimal lightness or darkness in dental x-rays requires a comprehensive approach that considers various factors, including technique and equipment settings. By educating the staff on some of these variables it can empower them to be involved in optimizing the images and “course correcting” when problems arise.

In February, the Journal of the American Dental Association published new recommendations aimed at enhancing radiation protection in dental radiography and cone-beam computed tomography (CBCT). They did this in partnership with the FDA. See article

One of their key recommendations is that lead aprons and thyroid collars are no longer recommended for patients during dental x-ray exams.  The main reasoning is they found a higher risk of the aprons and collars getting in the way of the imagery, which can result in more retakes

Other medical organizations have been making similar points for some time. In 2019, the American Associations of Physicists in Medicine concluded that the use of patient lead aprons should be discontinued as they were both unnecessary for safety and had the potential to jeopardize the quality of images. In 2021, the American College of Radiology also recommended discontinuing lead shielding.

Some thought leaders in radiology and medical physics have also made statements that lead aprons and other lead shields provide no additional benefit to the patient except for some psychological comfort.

So why would a dental office continue to use lead aprons?  There are at least two reasons:

First, your state (or local) laws may still require it.  The ADA position is simply a recommendation, and it does not overrule regulations that still require it.

Second, there may still be a comfort level from both staff and patients that may be hard to overcome because moving away from lead aprons may be a challenging cultural shift. Many patients and dental professionals have been conditioned to think that radiation is scary and dangerous.  Therefore, they may perceive that NOT using aprons is reckless behavior.

Furthermore, patients may see staff and doctors continue to wear shielding when in the X-ray room. There may be good reason for this as they work around x-ray modalities every day, and they enjoy no diagnostic benefits of getting the X-ray. However, this may create more concern in he patient’s mind, and may mean that the staff may have a hard time convincing them. 

In this case, it may be simply more reassuring to give the patient what they want and provide an apron for them.

There has been much controversy recently in the area of Dental Loss Ratios with Dental Insurance companies.  This brief article will attempt to lay out the sequence of events along with the key disagreements along the way.

The concept of a Dental Loss Ratio (DLR) refers to a strategy to attempt to force insurance companies to prioritize funding going toward patient care.  Specifically, it refers to a metric of how much of the company’s total spending is actually going toward patient care versus other administrative efforts like marketing, executive salaries, etc.

The strategy has its roots in the Affordable Care Act passed in 2010.  The ACA implemented a Medical Loss Ratio with the intent of holding health insurance companies accountable.

Over the years, there have been a number of states that have attempted to create and pass legislation that would force insurance companies to report and operate to a certain Dental Loss Ratio.  However, most of these efforts either stalled in the law-making process, or became significantly watered down by the time anything actually passed. 

The National Association of Dental Plans (NADP), not surprisingly, has fought against the concept of Dental Loss Ratio guidelines.  Their stated reasoning is that implementing these laws would add additional administrative costs and would also prevent smaller insurers from playing a role in the market.

In November of 2022, Massachusetts initiated a direct ballot initiative, many times referred to as “Question 2” on the ballot.  This ballot measure required dental health insurance companies to maintain a Dental Loss Ratio of at least 83%.  In other words, the companies had to spend at least 83% of their total budget on patient care.  If they failed to do so, they were required to rebate the difference directly to patients.  The ballot measure passed overwhelmingly.

The group that spearheaded the ballot initiative in Massachusetts thought this law could serve as an ideal model for other states to implement.  The ADA, who supported the efforts in Massachusetts, agreed, and set about to create a model that could be implemented in other states.

However, the path that the ADA took to create a Dental Loss Ratio implementation model created controversy in the dental community.  In particular, the group who spearheaded the effort in Massachusetts, led by Dr. Mouhab Rizkallah, became outspoken critics of the ADA strategy. [https://www.tdmr.org/ada-under-fire-for-dental-loss-ratio-compromise/]

The crux of the disagreement lies in how aggressive the model should be toward the insurance providers, and how much the NADP should have been involved in the process.  In addition, there is frustration on the part of the group that lead the Massachusetts effort that they were not involved in the ADA effort.

The ADA worked with the National Council of Insurance Legislators (NCOIL) to develop the model of how to implement the DLR.  The NCOIL pushed the ADA to gain agreement from the NADP.

The resulting model that was agreed to by the NADP was touted by the ADA as a victory because they felt it improved insurance company accountability by forcing insurance companies to measure DLRs and report DLRs to regulators.  The model also gives a commissioner the ability to “…take remediation or enforcement actions against [insurers], including ordering such carriers to rebate…” [https://ncoil.org/wp-content/uploads/2024/01/NCOIL-DLR-Model-Health-Cmte-Adopted-1-26-24.pdf]

Criticisms of the approach, and the resulting model, include:

• The definition of the DLR allows the insurer to remove costs going toward “non-profit” work from the denominator. There are some that believe this would give insurers the ability to funnel administrative costs into this bucket so as to inflate their DLR – which may erode accountability toward patient care.

• Key DLR metrics are calculated based on averages over 3 years, and targets are based on relative industry and market averages as opposed to absolute numbers. Some feel that this long time period will delay the corrective action that is desired.  Furthermore, critics feel that fluctuating targets create more opportunity for gaming the system and create less accountability.

• Some felt that the process to create the model was not as transparent as it could have been, as many key stakeholders felt they were not involved. In particular, the group who led the implementation of the DLR in Massachusetts felt that they should have been more involved in the process.

• Some also questioned whether the ADA was aggressive enough with the NADP, and if perhaps there was too much collaboration between these organizations.  For instance, Dr. Rizkallah pointed to the fact that there was never any agreement from the NADP in the Massachusetts initiative and that the result is more aggressive as a result of this independence.

In response to this, the ADA pointed out that the Massachusetts initiative was enacted based on a mechanism that allowed a ballot measure to be directly voted upon by the people.  They pointed out that there are only 14 states that even have this option.  Furthermore, even for those states where it did apply, they felt that direct ballot initiatives were extremely risky.  It appears that the ADA’s intent was to create a model that could withstand the legislative process across most states. 

As a result of the disagreement between some dentists and the ADA, a petition was created that received over 1300 signatures to prevent ratification of the ADA-recommended DLR model.  However, at the NCOIL meeting in April, it appears that it was ratified.

According to the ADA, Illinois, Nebraska, New York, Oklahoma, Pennsylvania, Rhode Island, Virginia, Washington and West Virginia have introduced DLR legislation in 2024. Arizona, Colorado and Nevada adopted legislation in 2023, and New Mexico adopted legislation in 2022.

They say that nearly all of the bills would set a minimum ratio that dental plans must meet, with a corresponding rebate requirement for plans spending less than that minimum.

The ADA just recommended that dentists use rectangular collimators on intraoral x-rays.  Why do the states disagree?

A rectangular collimator is typically an adapter that can be placed over the round cone of a dental intraoral x-ray source that limits the radiation being emitted to a smaller rectangular shape.  The purpose is to reduce patient radiation by limiting the x-ray to only the radiation that will hit the sensor (or film).

In February, the Journal of the American Dental Association published new recommendations aimed at enhancing radiation protection in dental radiography and cone-beam computed tomography (CBCT). They did this in partnership with the FDA. 

(see more detail here)

One of the recommendations is to use rectangular collimation for intraoral imaging because it has been shown to reduce effective dosage to patients “by more than 40%”.

But there is only one problem.

Dentists can’t get rectangular collimators.

At the time that the ADA published their report, there was only one state that required rectangular collimation on dental x-ray machines:  Colorado.  Ironically, that same month, the Colorado Board of Health rescinded this requirement.

The reason?     “…distributors and manufacturers have universally indicated that the add-on collimator devices envisioned by the current rule have been discontinued, are no longer being manufactured, and are not available for purchase on the open market. While some web sites continue to advertise the devices, the reality is that they are not available.”

The main reason that offices have stopped using them is that rectangular collimators can make it harder for the staff to take consistently diagnostic images.  This is because a rectangular collimator results in less margin for error in capturing the desired anatomy.  There is a higher probability of cone cut because the x-ray source must be more precisely aimed to hit the receptor.  

In February, the Journal of the American Dental Association published new recommendations aimed at enhancing radiation protection in dental radiography and cone-beam computed tomography (CBCT). They did this in partnership with the FDA.

This is a big deal because this is the first update to to recommendations on dental imaging safety and radiation protection from the Council in over a decade.

(download the full paper here)

They found that:

• 320 million dental imaging procedures (including intraoral, panoramic, and CBCT) were conducted in the United States in one year (2016)
• This was over 46% of all diagnostic imaging and nuclear medicine procedures nationwide

Here are the key recommendations:

• Lead aprons and thyroid collars are no longer recommended for patients during dental x-ray exams.  The main reasoning is they found a higher risk of the aprons and collars getting in the way of the imagery, which then results in more retakes
• Digital sensors are recommended over film because digital sensors result in a “dramatic” decrease in the dose per acquired image
• Intraoral x-rays should operate between 60kV and 80kV
• Operator should stand at least 2 m from the x-ray tube head (i.e. the source) and at 90 to 135 degrees from the beam path when other barriers are not available
• CBCT should NOT be used as the primary or initial modality
• Handheld x-rays should be stored securely when not in use so as to assure they are not used by an untrained person

We’ll be sharing more analysis and implications on these items in upcoming posts

What are the different types of dental x-ray machines and what are their advantages and disadvantages?

Many health clinics, hospitals, and traditional dental facilities may be considering adding dental x-ray to their facilities for the first time. However, they might not be fully aware of the key equipment needed for this purpose. This article aims to provide a comprehensive summary of the different types of dental x-ray machines along with their key options.

There are two fundamental types of dental x-ray: intraoral and extraoral.

Intraoral X-ray Machines

Intraoral x-ray machines create radiographs of the teeth by placing the sensor inside the patient’s mouth, while the x-ray source remains outside, typically against the patient’s cheek.

To capture intraoral dental x-rays, clinics will typically require the following equipment:

X-ray Source: The dental x-ray source is the machine that is generating the x-ray. When many dental professionals refer to the “intraoral x-ray machine”, they are referring to this component.  There are typically three main types of dental x-ray machines.

• Wall Mounted X-rays: These units offer a more powerful output, resulting in better images even with less-than-ideal technique. However, they require mounting to a wall and cannot be easily moved to different locations.
• Handheld X-rays: Handheld units are easily portable, allowing for movement to different locations. However, their power output is typically only about 25% of wall-mounted units, which can make it difficult for inexperienced staff to consistently capture good images.
• Mobile X-rays: Mobile units are as powerful as wall-mounted x-rays but offer the ability to move through the clinic. However, they are not as compact as handheld units and require some floor space.

Learn more about dental x-ray products

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