Latest Patient Volume Data As Dental Practices Begin Opening Up

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According to CNBC, the health care sector lost a record 1.4 million jobs in April led by more than half a million job cuts at dentist offices, as the coronavirus pandemic kept most non-emergency health care services on hold nationally.  The staggering jobs losses mark a 53% decline in dental practice employment over two months.  All but 3% of dental offices nationally were shut down except for emergency appointments last month, according to the American Dental Association, and nearly 9 out of 10 had laid off staff. 

However, as bleak as things looked in April, the first week of May saw nearly half of dental practices bringing workers back, according to the ADA.  As states begin to reopen, last week marked a dramatic increase in patient volume as well staff hiring.

 

 

 

 

 

The ADA released their latest data in which they survey members on a number of questions related to their current activity.  For the week of May 4th, they found a dramatic increase in dental practice volume.  This was marked both by the percentage of practices saying they saw an increase in patient volume…

 

 

 

…as well as the percentage of practices saying they began seeing non-emergency patients. 

 

As might be expected, not all states were seeing the same increases in these two metrics.  The tables below compare state-specific data comparing May 4th responses to those two weeks prior, and those states that began to relax stay-at-home restrictions earlier correlate with the dental practices that saw volume increases.  

* respondents for these states were less numerous and so have higher uncertainty 

While everyone would agree that we still have a long way to go until dental practices are able operate at normal levels, these data imply that the first steps have been more dramatic than many expected.  Of course, like so many other areas, all will be watching closely to make sure that relapses in infection rates don’t occur.

 

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How Should a Dental Practice Return to Work After the Coronavirus?

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The ADA found that most dental practices across the country responding to their survey have seen their current patient volume drop over 95%. 

While balancing caution with a desire to take some steps back to normalcy, every state is developing plans to ease restrictions from the COVID-19.  We have been having many conversations with dental offices that are using their current downtime to prepare for the moment when their state tells them it’s ok to start seeing non-emergency patients again.

We have found a really effective toolkit to help a dental professional plan for operation of their practice in a world post-COVID-19.  It includes proposals for communications, checklists, and strategies for keeping both patients and staff safe in the waiting room, chairside and the office.   

Download the Return to Work Toolkit

We hope you find it useful.  Please feel free to reach out if we can assist in any way.

But more importantly, please stay safe.

I’m Installing a Cone Beam in My Dental Office. What Approvals do I Need?

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As Dental Cone Beam systems become more common in dental practices, we are seeing an evolution of the requirements that regulatory bodies are mandating for installation and operation.  While the company you purchase the unit from should be able to advise you on your local requirements, it’s helpful to have some visibility into where to look and what to be concerned about.  The last thing anyone wants is an inspector telling the dental office that they are out of compliance after everything is installed.

Typically, the requirements for dental cone beam installation and operation are defined at the state level, so this is always a good place to start.  However, be aware that larger cities (e.g. New York City) may have additional unique requirements on top of or independent from the state requirements.  

While each state may vary, these are some of the common requirements that many states will ask for:

The first item involves the certification of the installer and the operator.  Most states require that the installer be registered with the state as a certified x-ray technician.  Typically, this requirement would apply to the installation of any x-ray equipment (whether it be a dental cone beam, or an intraoral x-ray).  

The second area covers the certification of the dental office layout.  Some states have requirements to submit an office plan to the state for review and approval.  Some states require evidence that a radiation physicist has reviewed the plan.  Typically, whoever is reviewing the plan will be looking to see where the dental cone beam will be located in the office relative to other activity in the office.  For instance, the reviewer may be concerned if there is a waiting room on the other side of the wall.  In addition, they will typically be evaluating what shielding exists between the CBCT and adjacent rooms.  While some states look for (or require) lead shielding, many states find traditional dry wall sufficient.  

The third area involves ongoing maintenance and quality assurance.  It is common that a state will ask that the office simply follow the recommendations of the manufacturer (which are typically outlined in their manual).  However, some states may have additional requirements.

All of these items are typically not difficult to perform and follow.  However, it is important to be aware of them.  Of course if you have any questions yourself, please don’t hesitate to give us a call, and we can do our best to assist you.

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    Assessment of Obstructive Sleep Apnea Using a Dental Cone Beam

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    Dr. Hansen is a graduate of the Marquette University School of Dentistry and University of Florida College of Dentistry. He is Interim Program Director of Oral and Maxillofacial Radiology at the University of Florida College of Dentistry where he is a Clinical Assistant Professor and has a joint appointment in the University of Florida College of Medicine Department of Radiology. He maintains a private practice in Oral and Maxillofacial Radiology with BeamReaders® and can be reached at: matt@beamreaders.com

     

     

     

    Obstructive Sleep Apnea (OSA) seems to be a hot topic in the world of dentistry. Much like temporomandibular joint dysfunction a decade ago, there is great interest in sleep disorders brought about by new diagnostic measures and treatment options. What was once the purview of the physician, OSA diagnosis and treatment is now intersecting with dentistry. With this new focus though comes misinformation with the disease and the role of the dentist, and in particular cone-beam CT, in its diagnosis. To clear up some of this confusion, let’s talk about OSA and what role imaging plays. In order to do so it’s important to have an understanding of obstructive sleep apnea, how it’s diagnosed, and what the treatment options are. So let’s begin there.

     

    Obstructive Sleep Apnea

    Obstructive sleep apnea is part of a larger spectrum of sleep diseases referred to as sleep disordered breathing or sleep-related breathing disorders. These disorders are broken into three distinct syndromes, each with its own diagnostic criteria.1

    1.  Obstructive sleep apnea-hypopnea syndrome (OSAHS or OSA), which we will focus on here.

    2.  Central sleep apnea-hypopnea syndrome (CSAHS or CSA), which is periodic cessation of breathing without airway obstruction; this is commonly seen in the setting of heart failure or stroke.

    3.  Sleep hypoventilation syndrome (SVHS), which comprises several disorders where control of breathing is impaired resulting in improper respiration.

    CSA and SVHS may overlap with obstructive sleep apneas. In the aggregate though, these syndromes do not result in obstruction of the airway and we will not consider them in our discussion.

    OSA is a chronic disease affecting around 2-4% of the adult population (3-14% men and 2-5% women) with the highest prevalence among middle-aged men of higher weight.2,3,6 It is characterized by cessation or reduction in breathing with a maintained or even increased respiratory effort.1 As the name implies this is due to obstruction, either partial or full, of the upper airway during sleep and can result in snoring, upper airway resistance syndrome, or obstructive sleep apnea. The repeated airway obstructions cause a progressive asphyxia. This creates an increased respiratory effort against the collapsed airway which continues until the individual is aroused from their sleep.2 The continuous arousal from deeper sleep and sleep fragmentation generates many of the symptoms these individuals complain of, mainly lack of concentration, daytime sleepiness, fatigue, and mood alteration. Over time these symptoms build upon themselves and, as the disease progresses, can cause impaired performance at work, reduction in quality of life, and even major work-related or road accidents.2 The risks do not end at sleepiness however, the Wisconsin sleep cohort study, established in 1988, found a significant increase in mortality over an 18 year period in subjects with OSA.4 With greater understanding of sleep apnea and its influence on health and quality of life, the rising prevalence is becoming a public health crisis.5

    An apnea is defined as cessation of airflow for 10 seconds. In adults, a hypopnea is defined by a reduction in nasal pressure by at least 30% of baseline for a duration of at least 10 seconds and accompanied by oxygen desaturation ≥ 4%.7 In patients 18 or younger a hypopnea is defined as a reduction in nasal pressure of at least 50% compared with baseline, associated with an arousal, awakening, or oxygen desaturation of at least 3%, that lasts for a duration of at least two missed breaths.7 This loss of airflows result in increased respiratory effort to overcome the obstruction. It is this stage, the evaluation of obstructions, that we look to radiographic imaging.

    An obstruction, or airway narrowing and/or abnormal anatomy, lays the groundwork for a sleep apnea. As we progress into deeper stages of sleep there is increased pharyngeal muscle relaxation and loss of the normal muscle tone which leads to an increase in upper airway resistance. It is also known that during sleep the upper airway reflex dilator response is impaired which further serves to increase airway collapsibility and resistance. When the airway collapses or becomes obstructed, we need a stronger respiratory effort to maintain the same airflow.

    For example, imagine running a marathon. At the start your muscles are fresh and oxygenated and you are likely nasal breathing. As the race progresses fatigue sets in and you likely switch to mouth breathing to overcome nasal restrictions. This is similar in a sense to OSA. We try to nasal breathe as it is more efficient but increased resistance causes us to mouth breathe. Obstructive sleep apnea is like trying to run a marathon while breathing only through a straw. As we fall asleep, we lose tone in the pharyngeal muscles. If the airway is small or abnormal to begin with, this may create the perfect condition to obstruct it. To overcome the obstruction, you need to breathe harder which is reflected in snoring, or the vibration of the pharyngeal tissues as the air moves past. A point where the airflow cannot be maintained and we have an apneic or hypopneic episode which causes an arousal. The arousal typically awakens us, muscle tone is restored, respiratory effort is balanced, and we gradually fall back into deeper sleep to start the cycle over again.

    This is the major benefit of cone-beam CT imaging. it provides an anatomical evaluation of the airway at a lower radiation dose and cost than traditional multi-detector CT to detect possible obstructions. By allowing the dentist to evaluate the airway and correlate those findings with clinical examination and history, it puts them in the driver’s seat in identifying potential OSA sufferers and improving quality of life. With estimates that OSA is undiagnosed in 82% to 93% of adults, dentists can be at the forefront in screening for the disease.8

     

    How is OSA Diagnosed

    Notice that I said dentists can be at the forefront of screening, not diagnosis, as the role of dentistry in OSA has been somewhat controversial. That is because obstructive sleep apnea is a medical diagnosis, made by a physician, and in collaboration with a polysomnogram (sleep study). A recent joint statement by the American Academy of Sleep Medicine (AASM) and American Academy of Dental Sleep Medicine (AADSM) states “patients presenting with symptoms of OSA require a face-to-face evaluation conducted by a qualified physician trained in sleep medicine”.9 The diagnosis of OSA therefore requires consultation with a physician to include clinical examination and diagnostic testing. The clinical evaluation for OSA should incorporate a thorough sleep history and a physical examination that includes the respiratory, cardiovascular, and neurologic systems.10 Furthermore, polysomnography is the standard diagnostic test for the diagnosis of OSA in adult patients in whom there is a concern for OSA based on a comprehensive sleep evaluation.10

    Diagnostic Criteria for OSA:  The Canadian Thoracic Society enumerates this by stating that diagnosis must meet certain criteria as follows.1  The individual must fulfill criterion A or B, plus criterion C:

    A.  Excessive daytime sleepiness that is not better explained by other factors.

    B.  Two or more of the following that are not better explained by other factors:

        • Choking or gasping during sleep;
        • Recurrent awakenings from sleep;
        • Unrefreshing sleep;
        • Daytime fatigue; and
        • Impaired concentration.

    C.  Sleep monitoring demonstrates five or more obstructive apneas/hypopneas per hour during sleep.

    To state concisely, it is a polysomnogram properly interpreted by a physician trained in sleep medicine, and following a clinical examination, that provides the diagnosis for OSA.

    A polysomnogram, or sleep study, is a diagnostic test designed to provide specific information about an individual through equipment and observation. This information can include O2 saturation levels, electrical activity in the brain, respiratory rates, heart rate, stage of sleep, eye movement, body movement, snoring, and unusual behaviors during sleep. This test is typically administered at a sleep clinic although home sleep apnea testing is gaining popularity. With testing at a sleep clinic being the gold standard, it is important that those utilizing home testing have the device evaluated for reliability and the results for validity. If there is any doubt then a proper polysomnogram is the preferred method.

    While the full study is interpreted, what we typically discuss is the apnea/hypopnea index or AHI. The AHI is the average number of apneic or hypopneic events during 1 hour of sleep. There are additional indexes we can look at that include respiratory effort-related arousal, commonly called the Respiratory Disturbance Index (RDI), but we will focus on AHI as that is what most are familiar with. The American Sleep Disorder Association classifies OSA as below:

                   Mild OSA = AHI 5-15

                   Moderate OSA = AHI 15-30

                   Severe OSA = AHI > 30

    It is important to note that this is for adult patients only. There is no threshold for AHI in younger individuals, as any apneic or hypopneic events classifies them with obstructive sleep apnea.11 Another commonly reported value is the O2 saturation nadir, or the lowest recorded O2 saturation value. A typical O2 nadir may be around 95% while anything less than 92% may indicate sleep apnea. Levels around 86% indicate severe hypoxia which left untreated may lead to brain damage or even death.

     

    How is OSA Treated

    Treatment of OSA is somewhat of a misnomer. In my mind, treatment means a definitive endpoint and is something we are very familiar with in dentistry. A patient presents with a carious lesion in the distal of 13 which is treated with a class II restoration. That’s it, the disease in the tooth is eradicated. A necrotic molar gets a root canal or extraction and a missing premolar gets an implant or bridge. Simple treatment treated simply.

    OSA requires a different mindset, one we aren’t used to as dentists. OSA, much like hypertension, requires management. This can come in many forms ranging from lifestyle modification to surgery, but requires the mentality that one solution does not fit all patients and that our service is not finalized at appliance insertion. Modification and adjustment of our management regimen, like titration, is important as OSA is a chronic disease. Our obligation does not end at the fabrication of an appliance.

    Before we talk about treatment though, let’s back up a bit and talk about risk factors as an understanding of them can help you understand the various treatments.  Clearly being a middle-aged male is a risk factor, so sex and age are risks. Studies have shown that men have an estimated 2 to 3 fold increase in OSA and have found a higher prevalence of the disease among middle-aged and older individuals.12 Other risks include:

    • Hypertension and cardiovascular disease.
    • Craniofacial morphology, something we as dentists are intimately familiar with. Specific areas of risk easily evaluated with CBCT:
      • Retrognathia
      • Macroglossia
      • Elongated soft palate
      • Posterior and inferior positioning of hyoid
      • Cervical spine and TMJ abnormalities
    • Familial and genetic influences play a role.
    • Multiple studies have also shown that higher weight bodies have a higher prevalence of OSA.4,12

    Understanding these risk factors, an initial treatment of OSA needs to consider the correlation of OSA with cardiovascular disease and higher body weights. Management will likely include CPAP, oral appliances, or even surgery too.

    Continuous positive airway pressure (CPAP) treatment is the gold standard for OSA. The device relies on stabilizing the upper airway with a continuous column of air that prevents collapse of the airway and resultant obstruction. CPAP is well-studied with its efficacy proven at managing OSA and reducing comorbidities. Unfortunately, CPAP adherence is low with reports of nonadherence as high as 83%.14 The pattern of CPAP adherence is established early, typically within the first week, and is a good predictor of long-term use which makes it a critical time for success.14 Generally if an individual adapts quickly and maintains compliance, they will benefit from and use CPAP. Poorly adapted or non-compliant individuals, as shown, have very high nonadherence rates. A multitude of factors influence compliance with machine-induced claustrophobia and behavioral/psychological factors playing a key role. Advancements in design and manufacturing have helped alleviate some of these factors, but the problem remains that this is a mask with attached tubing that needs to be worn throughout the night.

    Philips respironic CPAP machine

     

    Oral appliances will be most familiar to dentists as this is our primary role in management. These can be split into two categories; oral pressure therapy devices and oral appliances.

    Oral pressure therapy devices (OPTs) consist of a mouthpiece connected by tubing to a bedside station, similar to a CPAP without the mask. The device produces a gentle negative pressure in the oral cavity that pulls the tongue and soft palate forward to open up the airway and prevent collapse. OPTs have many positives including a high adherence rate and no severe adverse events.15 However, treatment success is low ranging from 25%-37% and individuals have complained of dry mouth, oral cavity discomfort, and dental discomfort.15

    Winx brand oral pressure therapy device

     

    Oral pressure therapy mechanism of action

     

    Traditional oral appliances (OAs) are similar to OPTs in that they prevent collapse of the airway. Unlike CPAP and OPTs, there is no negative or positive pressure applied to the airway. Oral appliances work by repositioning the tongue, mandible, or lifting the soft palate to increase the volume dimension of the airway. Like CPAPs, these have a unique advantage in that some can be titrated to achieve a desired result. Where CPAP titration is based on determining the ideal air pressure for treatment, oral appliance titration is based on adjusting the degree of advancement the device provides. This provides some control to the clinician but is inferior when compared to that of CPAP. However, that is not to say they provide no efficacy. In a recent meta-analysis, the authors found robust evidence that oral appliances reduce apneas and hypopneas while improving quality of sleep.16 Additionally, adherence rates for OAs are consistently higher than those for CPAP.15 Oral appliances continue to be a valid treatment option in OSA.

    Somnodent brand oral appliance

     

     

    Airway cross-sectional measurement with and without mandibular advancement appliance

    Without ApplianceWith Appliance

    Surgical treatment is an additional option available to the patient that has been extensively studied. It is generally reserved for those with bulky or misshapen tissue, or those refractory to other treatments. These surgeries range from tongue suppression and resection, maxillomandibular advancement, pharyngeal modification, and nasal cavity surgery. While many of these procedures have been shown to be effective, concerns about morbidity and adverse effects are common.15

    Lateral cephalometric demonstrating maxillomandibular advancement surgery combined with genial tubercle advancement to treat severe OSA

     

    Sagittal view cone-beam CT demonstrating uvulopalatopharyngoplasty (UP3 or UPPP) to treat severe OSA. Note the tissue recontouring in the posterior nasopharynx and shortening of the soft palate.

     

    Newer treatments for OSA include hypoglossal nerve stimulation to compensate for loss of genioglossus muscle tone during sleep, pharmaceuticals, and phenotyping to determine the specific pathophysiology of an individuals OSA.15 In reality, it is often a combination of treatments used to manage disease with lifestyle modification being first and foremost.

     

    The Role of Imaging in Obstructive Sleep Apnea

    To summarize our understanding of OSA, it is a disease whereupon the airway is narrowed or obstructed due to the tongue falling backwards and loss of tone in the pharyngeal musculature during sleep, which subsequently cause apneic and hypopneic events and a drop in blood oxygen levels. The disease is multifactorial and requires diagnosis by a trained physician aided by clinical examination and polysomnogram. There are multiple avenues of treatment with many patients requiring a combination of them to achieve control.

    So where does radiographic imaging come in?

    Well, it would stand to reason that an airway already reduced in dimension or obstructed would predispose an individual to sleep apnea; this belief forms the basis for radiographic imaging and it has now been established firmly that there is a strong correlation between airway narrowing in an awake patient and subsequent airway collapse during sleep.17

    To be clear, CBCT does not diagnose OSA. Anyone that tells you otherwise is incorrect.

    What CBCT does do is provide a detailed depiction of the airway and craniofacial anatomy that allows the clinician or radiologist to identify normal anatomy, variant anatomy, or pathological conditions that may cause obstruction of the airway. This invaluable information, combined with clinical screening, can help identify individuals that may suffer from sleep apnea. Indeed, with OSA afflicting a broad spectrum of people and dangerously underdiagnosed, dentists can serve on the front line of screening.2,3,6,8 Further supporting the dentists role in screening, CBCT made for dental treatment routinely includes portions or all of the upper airway and is made at a lower radiation dose and cost than traditional multi-detector CT used in medicine. Dentists and cone-beam CT are ideally situated for this task.

    Before we talk about how, though let’s address the elephant in the room…How does a radiograph made of a patient standing up and awake have any reliability in predicting the anatomy of a patient supine and asleep?

    Simple, it doesn’t.

    Imaging is not a magic wand that you can wave over the patient and diagnose airway collapse, but it doesn’t matter and we don’t necessarily need the patient supine and asleep. As discussed above, studies have consistently shown there is a strong correlation between airway narrowing in an awake patient and subsequent development of apneas while asleep.17 The fact that a patient is awake and standing during a CBCT doesn’t matter. A narrow airway that will only get narrower when they fall asleep does.

    Normal airway dimensional measurements

     

    Narrow airway dimensional measurements with false color added to demonstrate restriction. Patient is at moderate risk for OSA.

     

    Radiographic evaluation of the airway requires systematic and thorough review of the anatomy combined with accurate measuring. If uncomfortable or unfamiliar this is a task best left to a trained radiologist. It is important to review all anatomy in the CBCT for abnormality; however, several key areas have been identified as strongly correlating with OSA:17

    • Soft palate length
    • Oropharyngeal airway length
    • Tongue length
    • Retropalatal cross-sectional measurement
    • Retroglossal cross-sectional measurement
    • Underdeveloped maxilla and/or mandible
    • Inferiorly descended hyoid

    Come on just give me the number.

    The number, the oropharyngeal cross-sectional measurement encompassing the retropalatal and retroglossal measurements, the bane of the radiologists existence. Hyperbole aside, it is important to understand the cross-sectional measurement is just that…a measurement. It is a number generated by manual and augmented segmentation of the airway and susceptible to user variance, patient variance, and software variance. In and of itself it is meaningless, but as part of a systematic review and clinical screening, it can provide a vital understanding of the airway. The oropharyngeal cross-sectional measurement provides us with the smallest diameter of the airway, where it occurs, and whether it is predominantly mediolateral narrow, anteroposterior narrowing, or both.

    Airway cross-sectional volume measurement demonstrating moderate to severe risk of OSA

     

    The oropharyngeal cross section dates back to many of the early studies utilizing CT for airway assessment.18,19 These studies looked at anatomic abnormalities in patients with OSA to see if there were common findings and what role CT could play in screening. Across multiple studies, consistency started to arise between a cross-sectional measurement of ~50mm2 and severe obstructive sleep apnea. This baseline provides the scale that many radiologists use today:

     

    Oropharyngeal airway cross-sectional measurement

    OSA Risk

    <52mm2

    Severe

    52-110mm2

    Moderate

    >110mm2

    Mild

    Approximate risk of obstructive sleep apnea based off oropharyngeal cross-sectional measurement

     

    Key areas of evaluation also include the soft palate length, the total oropharyngeal airway length, the position of the hyoid, and any craniofacial or cervical abnormalities. In younger individuals, it is common to see tonsillar hyperplasia. This strongly correlates with obstructive sleep apnea and adenotonsillectomy is a common first-line treatment of OSA in children.20

    Long soft palate (yellow arrow) with narrow retropalatal space and large retroglossal space denoting a severe risk of OSA

     

    Inferiorly descended hyoid and narrow oropharyngeal airway space denoting severe risk of OSA

     

    Exaggerated cervical lordosis (yellow arrow) and narrow oropharyngeal airway denoting severe risk of OSA

     

    Adenoidal hyperplasia (yellow arrow) and narrow oropharyngeal airway denoting severe risk of OSA

     

    In summary, an airway evaluation is not just generating a number. It is systematic review of the entire anatomy to evaluate abnormalities and provide an understanding of clinical findings and patient concerns. Above, we just focused on the pharyngeal airway, in practice the nasal cavity, spinal architecture, TMJs, and skull base need evaluation. Our analysis extends from the tip of the nose to the epiglottis and is so much more than a single cross section. To return to our original question as to what role CBCT plays in obstructive sleep apnea evaluation, it turns out quite a bit. Generating a cross-sectional measurement can prove useful, but it is the 3-dimensional depiction of anatomy that proves of greatest benefit. If you’re on the fence about cone-beam CT and obstructive sleep apnea maybe this can help get you off it.

     

    References:

    1. Fleetham J, Ayas N, Bradley D, et al. Canadian Thoracic Society guidelines: diagnosis and treatment of sleep disordered breathing in adults. Can Respir J. 2006;13(7):387–392. doi:10.1155/2006/627096
    2. Spicuzza L, Caruso D, Di Maria G. Obstructive sleep apnoea syndrome and its management. Ther Adv Chronic Dis. 2015;6(5):273–285. doi:10.1177/2040622315590318
    3. org. (2020). Sleep breathing disorders – ERS. [online] Available at: https://www.erswhitebook.org/chapters/sleep-breathing-disorders/ [Accessed 3 Jan. 2020].
    4. Young T, Finn L, Peppard PE, et al. Sleep disordered breathing and mortality: eighteen-year follow-up of the Wisconsin sleep cohort. Sleep. 2008;31(8):1071–1078.
    5. American Academy of Sleep Medicine – Association for Sleep Clinicians and Researchers. (2020). Rising prevalence of sleep apnea in U.S. threatens public health – American Academy of Sleep Medicine – Association for Sleep Clinicians and Researchers. [online] Available at: https://aasm.org/rising-prevalence-of-sleep-apnea-in-u-s-threatens-public-health/ [Accessed 3 Jan. 2020].
    6. Kapur, V., Auckley, D., Chowdhuri, S., Kuhlmann, D., Mehra, R., Ramar, K. and Harrod, C. (2020). Clinical Practice Guideline for Diagnostic Testing for Adult Obstructive Sleep Apnea: An American Academy of Sleep Medicine Clinical Practice Guideline.
    7. Rajagopalan N. Obstructive sleep apnea: Not just a sleep disorder. Journal of Postgraduate Medicine. 2011;57(2):168. doi:10.4103/0022-3859.81866.
    8. Chiang HK, Long A, Carrico CK, Robinson R. The prevalence of general dentists who screen for obstructive sleep apnea. J Dent Sleep Med. 2018;5(3):55-60.
    9. American Academy of Sleep Medicine; American Academy of Dental Sleep Medicine. Policy Statement on the Diagnosis and Treatment of OSA. American Academy of Dental Sleep Medicine website. [Accessed 3 Jan. 2020]. http://aadsm.org/osapolicystatement.aspx. Published December 7, 2012.
    10. Kapur VK, Auckley DH, Chowdhuri S, Kuhlmann DC, Mehra R, Ramar K, Harrod CG. Clinical practice guideline for diagnostic testing for adult obstructive sleep apnea: an American Academy of Sleep Medicine clinical practice guideline. J Clin Sleep Med. 2017;13(3):479–504.
    11. Berry RB, Albertario CL, Harding SM, et al for the American Academy of Sleep Medicine. The AASM Manual for the Scoring of Sleep and Associated Events: Rules, Terminology and Technical Specifications, Version 2.5, www.aasmnet.org, American Academy of Sleep Medicine, Darien, IL 2018.
    12. Yaggi H. K., & Strohl K. P. Adult obstructive sleep apnea/hypopnea syndrome: Definitions, risk factors, and pathogenesis. Clinics in Chest Medicine, 2010;31(2), 179–186.
    13. Peppard PE, Young T, Palta M, Dempsey J, Skatrud J. Longitudinal Study of Moderate Weight Change and Sleep-Disordered Breathing. 2000;284(23):3015–3021.
    14. Weaver TE, Grunstein RR. Adherence to continuous positive airway pressure therapy: the challenge to effective treatment. Proc Am Thorac Soc. 2008;5(2):173–178. doi:10.1513/pats.200708-119MG
    15. Calik MW. Treatments for Obstructive Sleep Apnea. J Clin Outcomes Manag. 2016;23(4):181–192.
    16. Zhu, H. Long, F. Jian, J. Lin, J. Zhu, M. Gao, et al. The effectiveness of oral appliances for obstructive sleep apnea syndrome: a meta-analysis. J Dent. 2015;43 (12): 1394-1402
    17. Whyte A, Gibson D. Imaging of adult obstructive sleep apnoea. Eur J Radiol. 2018;102:176–187. doi: 10.1016/j.ejrad.2018.03.010.
    18. Li HY, Chen NH, Wang CR, Shu YH, Wang PC. Use of 3-dimensional computed tomography scan to evaluate upper airway patency for patients undergoing sleep-disordered breathing surgery. Otolaryngol Head Neck Surg 2003:129:336–342.
    19. Galvin JR, Rooholamini SA, Stanford W. Obstructive sleep apnea: diagnosis with ultrafast CT. Radiology. 1989;171:775–778.
    20. Lind MG, Lundell BP. Tonsillar hyperplasia in children. A cause of obstructive sleep apneas, CO2 retention, and retarded growth. Arch Otolaryngol. 1982 Oct;108(10):650–654. doi: 10.1001/archotol.1982.00790580044015.

     

     

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      Why Won’t My Panoramic X-Rays Show the Anterior Apices?

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      One of the most common complaints we hear with many panoramic x-ray systems is lack of visibility of the anterior apices – both upper and lower.  The office staff will work very hard on their technique, and they will make sure their panoramic x-ray is precisely calibrated and aligned.  However, with some systems, they cannot consistently capture this anatomy. 

      While technique plays an important role, there are other factors at play, and an often-overlooked root cause may be the equipment.  This is because in many cases, no matter what is done, some equipment just doesn’t have the capability.

       

      Why does this happen?

      There are a number of factors that make it difficult to capture good anteriors in a panoramic image.  For instance, unlike other parts of the dentition, scanning the anteriors means the beam must travel through the spine, which means the panoramic x-ray must increase the power in the middle of the scan to account for the additional bone.  If the panoramic x-ray is not doing this properly, it can affect this region in the resulting image.  Another factor can stem from technique.  For instance, having the patient swallow and place the tongue on the roof of the mouth can also help enhance visibility in the maxillary region of the image. 

      However (unfortunately), even if all these other aspects are done correctly, the reality is that for many panoramic x-ray machines, they still won’t have the ability to capture this anatomy for many patients.  The reason for this is a combination of anatomy and the limitation of the panoramic x-ray equipment.

       

      Background

      First, a quick explanation of how panoramic x-rays work.  Most panoramic x-rays, when they rotate about the patient, are capturing a U-shaped layer of data.  This is referred to as the “focal trough”.  Think of a rectangular piece of paper that is bent into an arc and placed on its side.       

      The anatomy that is captured in the panoramic radiograph is dependent on the location and the cross-sectional “thickness” of this focal trough.  If the anatomy falls outside of this U-shaped focal trough, it will not be clearly visible on the resulting image.  Because of this design, the anterior region is much more difficult to capture clearly in the panoramic image.  This difficulty stems from a few challenges that are working against the dental professional – some are obvious, and some are more subtle.

      First, there is the obvious reason that the anteriors are just narrower than the posteriors.  There’s just less margin for error.

      Second, for most of the dentition, the patient’s teeth are roughly vertical.  However, the anteriors (e.g. #8, #9, #24, #25) are typically not.   These teeth, particularly the mandibular anteriors, typically have a dramatic angle to their emergence profile.  As a result of this emergence profile, it can be very difficult (if not impossible on some patients) to capture the crowns and the apices of both mandibular and maxillary anteriors in the same scan.  This is because these points are not all in the same vertical plane.


      Third, the thickness of this focal trough (i.e. what anatomy can be captured) for most panoramic x-rays is also narrower when scanning the anteriors.  This is driven by the physics of most machines that are designed to rotate within a very compact space.  This narrowing means that it’s even harder to capture the full length of both mandibular and maxillary anteriors (because there is even less margin for error).  

      So what is a dental professional to do?  Simply resign herself to not getting good visibility into this region?  Take multiple scans with the patient in different positions?

       

      There is another way

      There are dental panoramic systems that are not limited to a single plane, and in fact have the ability to capture many focal troughs with one scan.  These systems do this by taking many layers of varying depths in the buccal-lingual direction (some have the ability to capture over 50 layers).  Typically, all this data is captured in a single scan, and then each layer is represented as a separate panoramic scan.  With all this data, the user has the ability to change which panoramic they would like to see with a click of the mouse.

      It’s almost like the dental professional has a stack of many panoramic x-rays with each representing a slightly different view of the anatomy – even those anterior teeth with dramatic emergence profiles. 

      Let’s take a look at an example.

      Here is a section from a typical panoramic radiograph.  In it, because of the reasons we just discussed, we can see that the image does not show the apices of the maxillary anteriors very clearly. 

      If this was taken with a panoramic x-ray that cannot capture multiple focal troughs, then the office is stuck with this image.

      Luckily, because the panoramic x-ray performing the scan has the ability to capture many focal troughs, the operator can choose from any of the other panoramic images that were captured in that scan.  Very quickly, the operator can select the image that reveals #8 and #9.  This image is from the same panoramic scan as the one above.  Same patient.  Same scan.

       

      Similarly, with the mandibular anteriors, viewing the original panoramic shows lack of clarity in the apices. 

      However, because this patient was scanned on a panoramic x-ray than can shift the focal trough, these apices can also be revealed.  Again, this is done simply by using the data captured during the original scan – no additional scans are needed.  You’ll notice that in this “layer”, the crowns are less visible.  This is because the maxillary anteriors have dramatic angles to the emergence profiles and therefore the crowns are in a very different layer than the apices.

       

      So, in summary:

       

      Luckily, ImageWorks has you covered on this front.  The panoramic modality of both our 2D Panoura 18S Panoramic X-ray, as well as our X-era Cone Beam capture over 50 layers every time a pano is taken.  This is with no additional time and no additional dosage.  Furthermore, this is done automatically for every scan, so there’s also no additional clicking, adjusting or futzing by the operator.  

      In addition, it’s worth noting that the operator can easily save as many “layers” as they like in the patient’s study as separate panoramic x-rays.   Many of our offices will take advantage of this capability by storing multiple panoramic images for a particular patient scan because it’s so quick and easy to do so.  This allows them to take full advantage of all the information the system can offer.

      If you would like more information or would like to see for yourself, give us a call.

       

      Learn more about the X-era CBCT from ImageWorks

      Learn more about the Panoura 18S Panoramic X-Ray from ImageWorks

       



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        Cone Beam Case Study: Overextended Obduration

        Posted by & filed under Uncategorized.

         

         

        Dr. Matt Hansen is Clinical Assistant Professor of Oral and Maxillofacial Diagnostic Sciences in the Division of Radiology and the College of Medicine at the University of Florida

         

        Imagine a radiograph free of superimposition and distortion, cost effective, and easily tolerated.  Now imagine full manipulability, being able to reconstruct and reformat the radiograph in any plane you desire, and the ability to diagnose and treatment plan in 3-dimensions. It’s not challenging to visualize how this could benefit health care and lead to improved patient outcomes.  Indeed this is the very reason Computed Tomography (CT) has exploded, but dentistry lagged behind our physician colleagues in use of this technology.  There were many barriers.  Limited access to CT scanners, a higher cost, concerns of radiation exposure, and lack of familiarity were all reasons for under-utilization.  Where dentists saw a problem, imaging companies and scientists saw a solution and cone-beam computed tomography (CBCT) was born.

        Cone-beam CT provided the advantages of more traditional multi-detector CTs utilized primarily in medicine, but without many of the drawbacks.  This led to rapid adoption by the field of dentistry. With the ability to now diagnose and plan treatment using 3-dimensional radiographs, CBCT is leading the digital revolution in dentistry and providing unparalleled information to drive clinical and patient confidence.

        With this in mind, I wanted to share a few example cases where the Cone Beam scan played a vital role in patient diagnosis and treatment.

         

        Endodontics

        Among clinicians, few have benefited as greatly as endodontists with the introduction of CBCT.  The ability to view complex root canal systems, free from superimposition and distortion, has been a resounding success.  CBCT does not end at canal anatomy however.  The information gained about sinus pathosis, neurovascular channels in the vicinity of treatment, resorptive defects, and root fractures are invaluable. It is easy to see why new accreditation standards for endodontic residency programs include in-depth training in CBCT. It’s easy to promote the benefits of 3D imaging, but as they say:  a picture is worth a thousand words. To illustrate: An older female presented to her dentist with a chief complaint of sensitivity in the left maxilla.  Following clinical examination which localized the pain to the premolar region, a periapical radiograph was made.

        The radiograph depicted endodontically-treated 13 with a persistent periapical radiolucency.  The obturation of 13 was over-extended and re-treatment was planned. This is an everyday occurrence in dental offices throughout the country.  In terms of confidence, we know:

        • There is an apical lucency on 13
        • The obturation is over-extended,
        • The patient has localized pain to this tooth.

        But do we know why?

        Our treatment options depend on our diagnosis. How confident are you in your diagnosis? Neither was the clinician, so they asked for a CBCT.

        In a world of grey, the CBCT was black and white.  The patient had an unobturated buccal canal (yellow arrow).  With confidence in our diagnosis, we have confidence in our treatment.

         

        Implants

        Implant dentistry has been another benefactor of 3D imaging. The ability to accurately assess bone quality and quantity, as well as the morphology and local anatomy, has dramatically increased the access of implant dentistry. Now one is able to accurately assess a site, plan the placement and surgery virtually, and then 3D-print a surgical guide. With these tools, implants are within the reach of all clinicians. It’s not just implant planning and guide creation that benefits us; it’s recognition of anatomy, accurately portrayed, that drives CBCT.

        Let’s look at a case where the CBCT prevented violation or aberrant anatomy. This was an older gentleman with failing #14 interested in replacement with an implant.  A panoramic radiograph was made for initial assessment.

        The panoramic depicted sufficient bone in the left maxilla and the patient was planned for extraction, socket preservation, and later implant placement. The patient’s healing was unremarkable. The socket preservation healed appropriately and aided in bone conservation. In preparation for surgery, a CBCT was made.  Fortuitously so, because it depicted the posterior superior alveolar neurovascular channel entering into the alveolar process at the surgical site. The yellow arrows point to the canal.

        The posterior superior alveolar neurovascular channel is the conduit for the nerve and artery of the same name.  They arise, as branches of the maxillary artery and nerve, in the pterygopalatine fossa and extend inferiorly and anteriorly along the maxillary sinus wall.  The channel can be classified into 3 main types: a canal, a groove in the sinus wall, or a combination of an intraosseous and extraosseous route. Typically, the canal is located more superior on the sinus wall, far out of the reach of an osteotomy drill, but in this case the channel had descended into the alveolar process and was located at the apex of the proposed site.  Without CBCT, we would not know this vital structure was there until it was too late. CBCT is a game changer, not just on the planning side but also in avoiding complications.

         

        Oral Surgery

        When talking about avoiding complications, it would be remiss to not discuss the great strides CBCT has made in oral surgery procedures.  From neoplasm assessment to surgical planning, CBCT has revolutionized the diagnostic work-flow of surgical practice.  Tumors can be resected with confidence, Le Forts can be planned, and fractures can be approximated and fixated with accurate knowledge of the local anatomy. Now these are limited procedures outside the scope of a general dentist office, so most would ask how does this benefit me? Look no further than the third molars.

        Third molar extraction is a common oral surgery procedure with some estimates of up to ten million wisdom teeth extracted annually. Many complications can arise from third molar extraction ranging from mild discomfort to paresthesia.  Mandibular canal location is of utmost importance when considering extraction of 17 and 32, and this is where CBCT shines. Previously a dentist could only rely upon cryptic signs such as canal darkening, narrowing, displacement, or interruption to determine mandibular canal. The sensitivity and specificity of this method tended to be poor in evaluating canal proximity. With potentially permanent and litigious complications, better evaluation is needed when there is doubt as to canal involvement.  Here is a panoramic radiograph reconstructed from a CBCT volume.

        The panoramic depicted impacted 17 and 32, with 32 being in close proximity to the mandibular canal. A CBCT was clearly justified.  The volume was evaluated and the canal was identified for the clinician.

        Upon review it was clear the canal contacted the roots of 32. A more interesting finding was noted in that the mesial root for 32 bifurcated at the apex and the canal traveled through this split. Having this information available enables the clinician to make confident and informed decisions, consenting or referring the patient as appropriate, and provide the appropriate treatment options.  An accessory mental foramen was incidentally noted in this study, an uncommon anatomical variant, and the patient was delighted to hear they were a rare and special individual.

        These are just a few examples of CBCT use in the modern dental office.  The diagnostic information gained combined with the efficiency, cost effectiveness, and relative low-dose of CBCT make it unparalleled in radiographic assessment.  Of course, with all the power that comes with 3D dentistry, having the equipment that maximizes your visibility will allow you to make the most from this modality.  The X-era CBCT from ImageWorks is the world’s first 0.2 mm focal spot CBCT, which will allow you to see most than you ever have.

        Learn more about the X-era CBCT



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          Case Study: Abscess on #24

          Posted by & filed under Uncategorized.

           

          Dr. Paul Blaisdell, Kuna, ID

           

          I recently had an X-era Cone Beam from Imageworks installed in our office.  Our staff was very excited to bring the new capability to our practice, and so far it has surpassed expectations by helping us provide a level of care for our patients that’s only possible with the information that 3D dentistry offers.  

          I wanted to share a unique case we’ve had with one of our patients.  This patient presented for a routine periodic exam. We hadn’t taken anterior PAs prior to this appointment.  However, upon seeing anterior PA’s, an apical radiolucency was noted on #24.

           

          A CBCT was taken after a negative cold test indicated a necrotic tooth.  When the CBCT was taken, we could clearly see that the abscess had completely perforated the labial bone at the apex of #24 and was close to doing so on #25.

          As we investigated more deeply, we identified another critical piece of information that would affect our treatment plan: a second canal on #24.    

           

          Had I initiated treatment on this particular tooth and kept my access very conservative, there’s a chance I would have missed the other canal. Furthermore, had I started the treatment and then found the second canal after access into the chamber, I would have had to spend time determining the anatomy of both canals.  For example, I would have had to determine if they had separate apicies.

          The X-era from Imageworks helped me in a number of ways.  First, it helped me feel very comfortable keeping this case in-house, which allowed me to keep the production.  This was an immediate quantitative benefit that shows me the system will pay for itself over a short period of time.

          Second, I was able to utilize the dramatic effect of such a high resolution volume to educate the patient in a clear and compelling way.   I was able to stress the importance of taking care of this situation.

           

          Finally, and most importantly, I’m confident that my proposed treatment plan is optimal for the patient in that it maximizes effectiveness while minimizing invasiveness.  

          This all took place just a couple for days after receiving our initial training.  While I’m an enormous fan of the image quality and information that it provides, I think my staff’s favorite part is that the machine is so easy to use. Furthermore, the team at Imageworks have been fantastic to work with, as they’ve been able to help us with any questions we’ve had along the way.

          Learn more about the X-era CBCT



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            ImageWorks Announces New X-era

            Posted by & filed under Uncategorized.

            Imageworks and Yoshida Announce Launch of Groundbreaking 0.2 mm Focal Spot Dental Cone Beam Imaging System

            Tuesday, August 13th 2019, Elmsford, NY —  Imageworks and Yoshida Dental today announced the launch of the first 0.2 mm focal spot dental cone beam imaging system in the United States.  The Panoura X-era utilizes one of the highest-precision focal spots in generating three-dimensional volumes as well as two dimensional panoramic and cephalometric images, which allows the dental professional to see a level of edge definition that is one of a kind.

            Don Vibbert, CEO of Imageworks said: “The Panoura X-era Dental Cone Beam is the first dental cone beam to be designed with this level of imaging resolution.  Dentists will be able to see a level of image edge definition that will give them absolute confidence in the plan they develop for their patient.  Our partnership with Yoshida has been a strong one for many years, and we are very excited to bring this extraordinary platform to our partners and customers in North America.”

            The X-era also utilizes one of the most powerful sensors in the industry with a 16-bit, Direct Conversion sensor.  This revolutionary design solves one of the fundamental challenges of most panoramic systems:  that the sensor material is not sensitive enough to convert x-ray directly into the digital signal.  Therefore, the system must perform multiple data conversions which degrade image precision.  The X-era’s Direct Conversion Sensor solves this problem by using an ultra-high sensitivity material that can convert x-ray directly to digital thereby avoiding the image degradation that occurs with most sensors.

            The 3D field of view creates enormous return on investment for the dental professional.  With multiple fields up to 16 cm x 8 cm, the X-era provides extraordinary flexibility whether the dental professional chooses to perform implants, endodontic evaluation, impacted tooth assessment, paranasal sinus evaluation, TMJ visualization, or airway studies.

            “We are excited to bring to the United States a platform that has helped so many dentists around the world. Our team has seen first-hand how enhanced image resolution can improve the standard of care,” said Kazutake Yamanaka, Vice president of Yoshida Dental Manufacturing. 

            Imageworks will be showing the X-era platform at the FDI ADA World Dental Congress Meeting in San Francisco on September 5th through the 7th  in booth 1066.  The X-era is available from more than three hundred dealer and service partner locations across North America.

            About ImageWorks

            Imageworks is a dental imaging manufacturer that has been creating advanced dental imaging technology for over 30 years.  Originally known as Dent-x, the company has a track record for developing imaging solutions that have revolutionized dental care.

            About Yoshida

            Since 1906, Yoshida has been synonymous with dental product manufacturing quality.  By combining decades of design and manufacturing experience with the drive of a new technology venture, Yoshida is a market share leader in Japan as well as a respected innovator in the global dental industry.

            Learn more at https://www.imageworkscorporation.com/cbct-and-panoramic-x-rays/

            For more information, contact Cathy Helwig at 914-592-6100, chelwig@imageworkscorporation.com



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              Most Common Questions When Buying a Dental Cone Beam Machine

              Posted by & filed under Blog.

               

               

              At ImageWorks, we’ve been helping dental practices make the most of their dental imaging for decades.  When it comes to dental cone beam systems, technology has come quite a way since we introduced our first generation 3D dental cone beam system in 2005 when we were called Dent-x.

              As technology advances, we are always excited to introduce a dental professional to the power and value of 3D imaging, because it is compelling for so many offices.  However, at the same time, with today’s 3D cone beam systems, we also like to say: with great power comes great responsibility.  Because of this responsibility, we think it’s important to offer information that allows new users to enter the world of 3D with eyes wide open.

              With this goal in mind, we thought it would be worthwhile to provide an overview of some of the most common questions that get asked when dental professionals are looking to implement a Cone Beam system in their office.  We hope you find this useful.

               

              What does CBCT stand for?

              Sometimes we find it useful to share a quick definition of terms, as different words can be thrown around that have similar meaning.  The abbreviation “CBCT” stands for Cone Beam Computed Tomography.  Computed Tomography is the general category of 3D medical imaging modalities that includes MRI and CAT Scan systems.  The “Cone Beam” refers to the class of CTs that are most commonly used for dental applications.  The description comes from the shape of the x-ray beam.  Sometimes these systems are referred to as “Cone Beams” or “Dental CTs” or simply Dental 3D imaging systems.

               

              Why is a Cone Beam scan so critical for implant planning?

              A dental cone beam can assist dental professionals in many ways.  These include:

                • Endodontic evaluation
                • Impacted teeth related to orthodontics
                • Paranasal sinus evaluation
                • TMJ visualization
                • Trauma evaluation
                • Immediate advanced imaging and treatment

              However, one of the most common reasons that many dental professionals bring a dental cone beam into their practice is to place implants.

              Given this fact, we are going to focus our discussion on this very common application.  There are a host of different ways that a Cone Beam system can assist with implant planning.  However, one of the most fundamental is providing visibility into the cross-sectional view of the location of the implant.  In 2012, the AAOMR published a position paper recommending that cross-sectional imaging be used for assessment of all dental implant sites. Cone-beam Computed Tomography (CBCT) is the cross-sectional imaging method of choice.  The cross sectional view provides critical information that cannot be gained from any purely 2D modality.  The example below shows the cross sectional view.

               

              What is the Field of View (FOV)?

              The Field of View (many times referred to as FOV) refers to the size of the volume captured in the scan.  Almost all CBCT systems on the market capture a volume that is shaped like a cylinder (i.e. a tin can).  Therefore, the FOV is expressed with two numbers, which are typically in cm.  The first number typically refers to the diameter of the circular face of the cylinder (the width of the tin can).  The second number refers to the height.

              The FOV typically advertised by a dental cone beam system will represent the largest FOV that can be captured by the system.  However, almost all systems will offer the flexibility to perform smaller scans as well (in other words, a system that advertises a 16 x 8 FOV will also typically offer the option of scanning smaller volumes like 8 x 8, 8 x 10, or 4 x 6, etc.  However, a system listing as a 8 x 8 FOV typically means that a larger scan is not an option with that system.

               

              How big of an FOV do I need?

              While there are many different options on the market, we sometimes put the different FOV sizes into three main groups.

              First are the very large FOV machines are those that can capture most of the cranium in a single scan (e.g. largest scan size of 16 x 16 and above).  These systems will be the most expensive and are typically used by oral surgeons or other specialists.

              Second are the smaller FOV machines (e.g. 8 x 8 or 10 x 10).  These can be an adequate dental cone beam system, as it allows capture of most of the essential anatomy.  Below is a sample of a volume in this range (3D reconstruction, axial and sagittal views):

              Potential challenges with cone beam systems that max out at this size may include:

              • Cutting off 3rd molars
              • Inability to perform airway analysis
              • Inability to capture both TMJs in a single scan
              • Little margin for error in patient positioning (i.e. suboptimal positioning may cause desired anatomy to fall outside the scanning volume)

              Third are the medium size FOV dental cone beam machines (e.g. 16 x 8).  Below are examples of a 16 x 8 volume (3D reconstruction, axial and sagittal views):

               

              What about 2D panoramic radiographs?

              Most dental cone beam systems today can also create 2D panoramic radiographs.  However, what many dentists aren’t aware of is that the panoramic capability of dental cone beams can vary dramatically.  This stems from the fact that dental cone beams typically generate their panoramic in one of two ways.  

              The first type of dental cone beam will utilize the 3D sensor to create the panoramic radiograph.  This approach will allow the manufacturer to save money.  However, the trade-off is that the panoramic radiograph will typically suffer in image quality, because a flat panel 3D sensor is not optimized for a 2D scan.

              The second type of dental cone beam possesses a separate sensor that is dedicated to and optimized for panoramic radiographs.  One example is a cone beam that has a Direct Conversion panoramic sensor, which is designed to reduce noise in panoramic and cephalometric scans.

              It’s worth noting that you would never know which type of cone beam you have by looking at it, because this is all happening “under the covers” (so to speak).  The noticeable difference will be in the panoramic scans.  

               

              What is the difference in patient dosage with a dental cone beam as compared to other modalities?

              To answer this question, it’s worth a quick definition of how dosage is typically quantified.  The most common approach to describing x-ray dosage is called “effective dosage”.  Effective dosage takes into account the anatomy being exposed in additional to the power of the exposure to provide a more accurate indication of health risk.  The typical unit of measurement is the “sievert” (Sv), or more commonly in the dental realm, the “microsievert” (μSv).

              Dosage for a cone beam scan is going to vary based on the parameters of the scan (FOV, kVp, mA, and exposure time, etc).  However, one study performed a few years ago (1) measured a number of medium sized FOV cone beams and found the effective dose to range from 83 μSv to 194 μSv.

              A typical panoramic x-ray can result in an effective dose of about 14 μSv.  A typical full mouth series (FMX) that includes 18 intraoral radiographs results in about 171 μSv of effective dose (2).

              Finally, to help patients put the dosage numbers into perspective, it may be worth comparing these to some common phenomenon from everyday life. According to the United Nations Scientific Committee on the Effects of Atomic Radiation, the average worldwide background radiation is about 2400 μSv per year or approximately 7 μSv per day.  A cross-country flight is about 30 μSv.  A medical chest CT is 7000 μSv.  While some patients can understandably get concerned about “CT” scans, it’s worth noting that dental CBCTs are a fraction of the dose when compared to medical CT scans.

               

              Will a dental cone beam system integrate with my existing systems?

              Integration is always a concern because almost every dental digital system is dependent on other parts of the workflow to deliver the quality patient care.  To organize ourselves, we will break it into two categories:  2D images (pans and cephs) and 3D volumes.

              For 2D panoramic x-rays and cephalometric images, integration is typically very straightforward, as the 2D images will be automatically exported into the office imaging software (i.e. the same software used to manage the intraoral images).  This interface may be a proprietary direct interface, or could be utilizing the industry-standard called “TWAIN”.  Either way, it’s no different than how a traditional panoramic x-ray would interface with the imaging software for an office.

              For the 3D volumes, typically the cone beam system will come with its own dedicated 3D management software.  This software will typically allow a given 3D scan to be shared throughout the office.

              There are scenarios where the office will need to use this 3D data for other purposes, like working with a lab, 3D printing surgical guides or milling crowns.  To determine if the 3D volumes integrate with the various other systems involved in these applications, there are two primary file formats that play a big role.

              The first file format to be aware of is DICOM, which is a standard format for digital medical images.  Most dental cone beam volumes are made up of hundreds of 2D DICOM files (these are the “slices” that are created by the CBCT when a scan is performed).

              Most dental cone beam systems create 3D volumes that are DICOM format.  This is important for things like opening volumes in other 3D software (if an office has a preference for 3D software that is different than that provided by the cone beam manufacturer).  DICOM format will also be important if the volume is provided to a lab who will then create the actual implant or will 3D print a surgical guide.  Typically, the lab will have specialized software that allows them to merge your DICOM format volume with data from an impression (whether this impression was generated via a physical model or optical scanner).

              The second file format to be aware of is called STL (short for stereolithography), which is the industry standard for 3D printers and CAD/CAM (Computer Aided Design/Manufacturing).  This format becomes important when 3D printing or milling is done.

              Some cone beam systems also offer the option of outputting the volume (or parts of the volume) in STL format.  This capability becomes important if an office plans to be more involved in the creation of implants, surgical guides or other appliances in-office.  If this capability is important to an office, it is worth checking whether the cone beam software can output STL formatted volumes.  Furthermore, it is also worth asking whether STL output comes standard with the Cone Beam software, or if it’s an add-on surcharge.

               

              Is there an increased legal liability with a CBCT?

              As you might expect, any time we wade into this area, our own lawyers request we remind everyone that we are not legal counsel, and you should always refer to legal professionals.  However, we are happy to share a few thoughts.

              To lose a lawsuit, typically a patient must prove that injury due to negligence was avoidable.  When it comes to placing implants, most legal advisors seem to recommend that there is much greater risk in NOT taking a CBCT scan.  This is because if there are complications and a CBCT was not taken, a court could determine that injury could have been avoided had the doctor gained additional information that a traditional dental cone beam scan could have provided.

              Regarding liability with reading a CBCT scan, the general consensus is that at a minimum, any provider who acquires CBCT scans is liable for not recognizing abnormalities or pathologies on any cuts used for the clinical indication.  

              Some dental practices attempt to protect themselves by having patients sign a waiver.  The opinion that seems be shared amongst the legal community is that waivers of liability have no legal effect and courts will ignore them.   Most jurisdictions that have considered the matter have held that physicians and hospitals cannot require patients to waive their rights to recover damages for negligence.

              Given that reading CT scans is a specialty in its own right, there is also consensus that more training is always a positive thing for the dental professionals who are acquiring 3D scans for the first time.  There are myriad courses both online and in person offering additional training on this topic.  Seeking out that training has no downside.

               

              What determines image quality?

              There are a host of different factors that can affect the resulting image quality ranging from positioning to the mode selected (modes that utilize longer scans and smaller volumes would have high resolution).  However, we thought it would be worthwhile to highlight a few key factors that can vary by equipment manufacturer.

              The focal spot size of any x-ray modality defines the edge definition of the object being imaged.  This is true whether it be a wall mounted x-ray, panoramic x-ray or dental cone beam.  The smaller the focal spot, the higher the precision of the radiographs.  This focal spot size can vary dramatically in panoramic and cone beam systems with some focal spots as large as 0.7 mm and some as small as 0.2 mm.

              The voxel size for 3D volumes represents the precision of the spatial resolution of the 3D volume.  The smaller the voxel, the higher the resolution.  It’s also important to note that the voxel size will also vary depending on the field of view that is used in a given scan.  Therefore, because (as mentioned above), most dental cone beam machines offer options for the Field of View (i.e. different size scans can be performed on the same unit) – that means that the voxel size will vary across different FOV sizes on the same cone beam machine.  The larger the Field of View, the larger the voxel size and the lower the resolution.  The voxel size of most systems will typically vary anywhere between 70 micrometers to 400 micrometers.

              For many (if not most) offices that use a dental cone beam, the panoramic x-ray modality is used more frequently than the 3D modality.  Given this, it’s important to note that not all dental cone beams create their panoramic x-ray radiographs the same way.  These typically fall into three categories:

              The first type uses the same sensor to perform both the 3D scan as well as the 2D scan.  With these systems, they are typically optimized for the 3D scans while the 2D panoramic scans can be suboptimal, which can lead to lower quality panoramic x-rays.  For instance, a typical high-quality panoramic x-ray would have a pixel size of 100 micrometers….  However, a 3D flat panel sensor with that level of resolution would typically be too expensive, so the design typically makes do with a lower resolution panoramic image.  These units may be ideal for offices for which the 3D scans are a much higher priority (and higher frequency) than the panoramic x-rays.

              The second type uses a dedicated sensor for panoramic x-rays.  However, the material used in the 2D sensor does not have the ability to convert the x-ray directly to a digital signal.  These sensors must convert the x-ray to light first, then convert the light to a digital signal.  This double conversion can result in a loss of image resolution in the resulting digital radiograph.

              The third type also uses a dedicated sensor for panoramic x-rays, but they utilize a Direct Conversion Sensor.  This means that the material used in the sensor is sensitive enough to x-ray radiation to be able to convert the signal directly to a digital signal, which allows the signal to retain its precision in the resulting digital radiograph.

               

              Are there special requirements to install and operate a dental cone beam in my office (different from other dental x-ray equipment)?

              The requirements for dental cone beam installation and operation typically are defined at the state level.  However, larger cities (e.g. New York City) may have additional unique requirements.  While the company you purchase the unit from should be able to advise you on your local requirements, there are a few main areas to be aware of.  The last thing anyone wants is an inspector telling the office that they are out of compliance after everything is installed.

              First involves the certification of the installer and the operator.  Most states require that the installer be registered with the state as a certified x-ray technician.  Sometimes, states will also ask that operators be registered as well.

              Second involves the certification of the office layout.  Some states have requirements to submit an office plan to the state for review and approval.  Some states require evidence that a radiation physicist has reviewed the plan.

              Third involves ongoing maintenance and quality assurance.  Most states ask that the office simply follow the recommendations of the manufacturer (which are typically outlined in their manual).  However, some states may have additional requirements.

              All of these items are typically not difficult to perform and follow.  However, it is important to be aware of them.

               

              Dental Cone Beam System is a big investment for any office. Understanding the pros and cons of different designs will help your team make sure there are no surprises.  If you have any questions, please give us a call to talk to one of our specialists.

               

              Learn more about ImageWorks Cone Beam Solutions

               

               

              1 –  “Effective dose range for dental cone beam computed tomography scanners”, European Journal of Radiology; Aug, 2010

              2 –  “Patient risk related to common dental radiographic examinations: the impact of 2007 International Commission on Radiological Protection recommendations regarding dose calculation” published in The Journal of the American Dental Association in 2008



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                Four Surprising Mistakes When Buying a Dental CBCT That Can Cost You Money

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                Dental CBCT has enormous diagnostic benefits that we have detailed in many places. However, we see some dental practice owners making the assumption that a positive business case will automatically flow from their investment. For many dental offices, a dental CBCT will be the largest single investment they ever make for the dental office. Creating a positive ROI for this large capex investment requires benefits that outweigh the cost. Therefore, without a plan, a good return is far from automatic.

                Based on our experience implementing dental imaging solutions for thousands of dental offices over 30 years, we have found four common mistakes.

                1. Ignoring the business case. The business case does not need to be an elaborate set of spreadsheets. It may be nothing more than a back of the envelope calculation. In addition, as with many business plans, assumptions will inevitably be required. We have heard many doctors make the point that because assumptions are required, it makes the whole exercise pointless. “How can I create a business plan if I’m just guessing at certain numbers?” Our view is that getting all the assumptions exactly right is less important. Rather, what’s more important is understanding all the benefits that can be generated, and then putting a plan in place to realize those benefits.

                The most obvious benefit is the ability to perform new services, like implants. In this case, you might estimate how many new cases you could do in a month. However, a common error is not accounting for possible opportunity cost of the procedures you are not doing when you perform these new services. In other words, if your office is operating at a healthy utilization, then the true benefit is the difference in income between the new service and the service that was displaced.

                Alternatively, perhaps you are already doing implants, and are just looking at the cost savings from sending patients out for 3rd party scans. In a similar fashion, while there are clearly savings if that scan could be done in-house, don’t forget to account for the added labor that’s now required to perform the activities that were being outsourced (including operating the unit). If your practice is not fully utilized, then this is likely a good tradeoff (because your staff has the bandwidth without adding headcount). However, if your staff is fully utilized, will this stretch your staff to the point where you will need to add headcount, which would then hurt your original business case?

                2. Ignoring Cash Flow Requirements. Even if the eventual business case for dental CBCT seems clear, for a new practice that’s just starting, there is the added challenge of managing cash flow during the start up period. Investing too early in a dental CBCT system can put the business case for the entire practice at risk if it means a higher probability of running out of cash during the start up phase.

                Typically, for a new office, most of the initial capex will be financed, which means that every month is going to have a breakeven revenue that will need to not only cover your fixed expenses, but also the monthly loan payment. Sometimes it’s useful to think about how many more patients you will need to see every month to pay for that dental CBCT. Conversely, how many fewer patients will you be required to see each month to break even if you didn’t have the dental CBCT (because your monthly loan payment is less)?

                Another scenario to consider with a start up office is: what happens if the ramp up is slower than expected? How much cash “buffer” do you have with the added expense of the dental CBCT vs if you didn’t have that incremental monthly payment? One feature to consider is if the dental CBCT capability can be added to a previously installed panoramic x-ray unit one or two years after the initial installation. This could be another very effective way to improve the cash flow for a start up that needs a panoramic on day one, but can wait to get cash flow positive before investing in a dental CBCT.

                3. Failing to budget time for training. Dental CBCTs are becoming easier to use and (for better or for worse) the software is doing more of the work. However, it still requires a knowledgeable master to fully tap into its capabilities. Given this, it’s important for the doctor and the staff to commit to investing the time to hone their skills on 3D dentistry. While clearly there are a lot of similarities between 2D imaging and 3D imaging, there are a number of fundamental differences. The good news is there are abundant resources available everywhere.

                4. Ignoring the benefits in patient perception. While the main driver for most dental professionals in implementing dental CBCT in their office is for the diagnostic capabilities, it would be foolish to overlook the value it can have with patient confidence and retention.

                One of the most underestimated values of dental CBCT that we constantly hear from dentists is the increase in case acceptance. When it comes to helping a patient visualize the recommendation of the dental professional, there are few tools more effective than the three-dimensional cross section of the patient’s anatomy that can be rotated and viewed from any angle. Using this tool, the dental professional can clearly explain the recommended plan, which makes the patient dramatically more comfortable and confident.

                In addition, we have seen dental practices realize additional benefits in patient perception through different forms of marketing. There are many that reference their dental CBCT as part of their normal marketing activities. Some display an array of sample 3D volume slices (anonymized, obviously) on monitors in the dental office. We have even seen an office place the dental CBCT in full view of the waiting room through a glass window that can be clouded for patient privacy. All of these steps help differentiate the dentist, which equates to more patient references and higher case acceptance.

                Dental CBCT has very clear diagnostic benefits for certain offices, but may not be right for everyone. To help you evaluate if it’s right for you, reach out to us to chat with one of our specialists.





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