Written by Stephen M. Miller, DMD, Stephanie C. Lacina, BA, and David C. Gakenheimer, PhD Monday, 31 August 2009 19:00
Seeing is believing! When intraoral cameras came on the scene in the early 1990s, patients were "wowed" by what they could see and the new way in which they could better relate to their own dental treatment. Dr. Woody Oakes, founder of Excellence in Dentistry, said "a picture is worth a thousand words; an intraoral dental image 10,000 words." Now we have digital radiology and computer-aided diagnostic (CAD) tools to derive information that might otherwise not be seen by the unaided eye.
This paper describes one such CAD technology and how it can help provide your patients better dental care and increase your business.
THE DIAGNOSTIC CHALLENGE
Diagnosing proximal dentinal caries can be a difficult task when relying solely upon visual inspection of radiographs. Improved methods of caries detection are of interest because timely treatment is so important for preventative care and is in the best interest of the patient. Ultimately, this kind of technology may save patients from painful and more expensive treatments.
Digital radiographs offer several major advantages over film. They provide the ability to make adjustments to the brightness, contrast, and sharpness within the image which can sometimes make caries more visible. In addition, they are available nearly instantaneously. According to some studies,1-12 digital radiography by itself does not provide an advantage over film in the difficult task of diagnosing interproximal caries. Yet, digital radiography has made other technological advancements possible that have played a positive role in improving caries detection. Such technological advancements, such as smart software, provide an invaluable service to the daily dental practice. This technology not only improves patient care through early detection, it provides a valuable patient education tool. One such software, known as the Logicon Caries Detector (PracticeWorks Systems), demonstrates how digital technology makes improved patient care a reality while also providing dentists with an easily demonstrated patient education tool. Quite often, patients do not accept recommended dental treatment for a myriad of reasons—from not being able to see the lesion in the radiograph—to wondering why they need treatment, since their tooth is not causing them pain. Smart software makes it possible to put the patient at ease by educating them through the latest technology.
UNIQUE IMAGE ANALYSIS TECHNOLOGY
Digital sensors collect thousands of shades of gray, while normal computer monitors are only capable of displaying 256 shades of gray. Image quality, the ambient lighting conditions, and time constraints, all affect a doctor’s visual capacity to resolve the shades of gray on the monitor and diagnose radiographs. Smart software programs make it possible to extract additional information from a digital radiograph that is not visually obvious. In turn, such software programs have the potential to increase earlier detection of the caries disease, allowing dentists to treat a significant number of additional surfaces in need of restoration that may have otherwise gone undetected.
In one study,13 it was proven that the Logicon Caries Detector program allowed doctors to detect 20% more cases of caries in need of restoration than they could from visual inspection only. The Logicon Caries Detector was first introduced in 1998 (after receiving a US patent14 and being cleared by the FDA15) as an add-in software program to the Trophy (now Kodak) RVG intraoral sensor system (available from PracticeWorks Systems), and it has been upgraded in response to requests from its many long-time users.
The current version of Logicon Caries Detector (version 4.0) includes the following: custom full-screen filters for sharpening and adjusting the brightness and contrast to make the caries easier to see with the naked eye; a new edge finding algorithms to enable the software to automatically work around small overlaps and reduce the need for manual tracing; a density analysis tool to find demineralized tooth material and patterns thereof associated with tooth decay; a region of interest adjustment tool to find the deepest extent of the caries with a manual over-ride; an embedded database of known caries cases to compare to new calculations; built-in training tools; and e-mail functions to help communicate to third parties including patients, insurance companies, and the manufacturer.
The program also displays 3 diagnostic aids: (1) an outline of the decay region on the radiograph showing the depth of the caries; (2) a plot of the tooth density change across the caries site; and (3) the probability that caries is present with a restoration decision threshold for caries entering the dentin. All of these features lend an extra hand to the dentist in improving patient care by promoting early detection of carious lesions, and providing aids that the patient can easily understand.
To demonstrate how effective smart software can be in aiding the daily dental practice, and how valuable it can be for putting a patient at ease, the authors of this article are presenting how the Logicon software aided Dr. Miller’s practice in a typical daily office environment to provide improved patient care and patient education.
For one patient, Dr. Miller’s recommendation to treat a couple of cavities was a bit disconcerting since the decay was not visually obvious to him in a digital radiograph taken of his teeth. This, combined with a Logicon Caries Detector analysis, made the patient extremely nervous and worried about accepting treatment. Despite the fact that he had been a longtime patient and expressed full confidence in Dr. Miller’s abilities, he was unfortunately still uncomfortable. The patient stated that "There is a distinct problem when a patient sees graphic outlines of caries, and graphs in red, indicating that cavities should be treated, but does not see the cavities themself."16 His nervousness inspired him to go home and research online how the Logicon program works.
Still unconvinced, he decided to contact the dentist for further clarification. The dentist pointed out that, in his experience, almost all caries show some visual evidence. Yet, oftentimes the evidence is apparent in the enamel but not necessarily in the dentin, making the determination of the depth of the decay quite challenging. Dr. Miller explained how the software outlines the caries site on the radiograph, and shows the tooth density change across the caries site due to demineralization of the tooth material as a result of the decay. This is based on the physics of the tooth, as captured in the image, which the software then compares to a database of known caries problems collected in a dental school.
The restoration decision threshold employed in the software is based on a comparison of the caries features in the new image to the histologically confirmed cases in the database. One can then visually see the caries outline on the radiograph and in the density plot, and then determine whether the decay is going into the dentin visually. While the human eye cannot detect all of the shades of gray in a radiograph, the software can analyze all of the shades of gray, look for the complete caries pattern, and outline it on a tooth.
Armed with this information and a better understanding of how this smart software worked as an important diagnostic aid in the dental practice, the patient finally felt confident in allowing the treatment. After discussing the software with the dentist, the patient decided that his doctor’s explanations described a system for caries diagnosis that "is superior to caries diagnosis done with x-rays alone [and visually]…I find it hard to conceive that it could be otherwise."
This particular patient benefited not only from early caries detection, but also from the additional education the doctor was able to provide from this diagnostic aid. After receiving treatment, the patient concluded that the "software system was a useful and important adjunct for detecting caries and making treatment decisions. He said, "It might help me keep all of my teeth!" In this case, the dental practice benefited by having a reliable diagnostic aid that allowed optimal care, while being able to put the patient’s fears at ease through educating him about his disease.
For those readers who are not completely familiar with this diagnostic technology, the Logicon program works in the following way:
Figure 1 shows the initial radiograph, as captured by the Kodak RVG 6100 intraoral sensor displayed in the Logicon software (launched from the RVG software). This sensor has a resolution greater than 20 line pairs per mm, and is the highest resolution intraoral sensor on today’s market. As one can see, even with this high quality image the decay is not blatantly obvious.
Figure 2 shows the same image in Logicon 4.0, enhanced with the software’s sharpening filter to increase the visibility of caries sites and the dentino-enamel-junction (DEJ). This unique filter, included in the Logicon software, enhances the enamel region of the tooth to help expose any radiolucencies that are caused by caries. There is clear evidence of decay into the dentin in the distal surface of tooth No. 5. In the mesial surface of tooth No. 4, there appears to be decay in the enamel but it is not visually clear whether it enters the dentin.
Figure 3 shows the Logicon density analysis results for the mesial surface of tooth No. 4. The software finds evidence of decay just penetrating the dentin; the probability a lesion is present in the dentin exceeds the decision threshold for restoration based on comparison to what is in its database of histologically confirmed cases of dentin caries. This case shows the value of the software since this surface would likely not have been restored at this time, based on the visual evidence in the radiograph alone.
In the case of the distal interproximal surface of tooth No. 5, the visual evidence of decay into the dentin certainly supports restoring the tooth. However, the Logicon analysis may be useful for patient education. Figure 4 shows the result. The software finds a classic decay pattern with the decay penetrating the enamel and narrowing as it reaches the DEJ, and then spreading out as it enters the softer dentin. The program predicts a high correlation with the dentinal lesion cases in our database, and the probability greatly exceeds the decision threshold for treatment as shown on the lesion probability chart. Although Logicon was not needed to diagnose this surface, the analysis can be helpful for patient education.
Finally, Figure 5 shows a picture taken of the preparation site when Dr. Miller restored these surfaces. The decay found in the teeth correlates with the predictions and results of the Logicon software. The decay was found to be just barely penetrating the dentin on the mesial of tooth No. 4, and more significant decay was present on the distal surface of tooth No. 5, where it had clearly spread into the dentin.
In summary, smart software makes important diagnostic technology possible. This aids doctors in their daily practice by increasing the aptitude for diagnosing caries, and the ability to reassure patients through educational tools that they need treatment. This all results in improved patient care. At the same time, patients benefit from smart software as they receive earlier treatment, saving them from more costly painful procedures in the future, while receiving peace of mind thanks to the educational value of the software.
- White SC, Yoon DC. Comparative performance of digital and conventional images for detecting proximal surface caries. Dentomaxillofac Radiol. 1997;26:32-38.
- Uprichard KK, Potter BJ, Russell CM, et al. Comparison of direct digital and conventional radiography for the detection of proximal surface caries in the mixed dentition. Pediatr Dent. 2000;22:9-15.
- Syriopoulos K, Sanderink GC, Velders XL, et al. Radiographic detection of approximal caries: a comparison of dental films and digital imaging systems. Dentomaxillofac Radiol. 2000;29:312-318.
- Nair MK, Nair UP. An in-vitro evaluation of Kodak Insight and Ektaspeed Plus film with a CMOS detector for natural proximal caries: ROC analysis. Caries Res. 2001;35:354-359.
- Hintze H, Wenzel A, Frydenberg M. Accuracy of caries detection with four storage phosphor systems and E-speed radiographs. Dentomaxillofac Radiol. 2002;31:170-175.
- Abreu M Jr, Mol A, Ludlow JB. Performance of RVGui sensor and Kodak Ektaspeed Plus film for proximal caries detection. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2001;91:381-385.
- Han WJ. A comparison of film and 3 digital imaging systems for natural dental caries detection: CCD, CMOS, PSP and film [in Korean]. Korean J Oral Maxillofac Radiol. 2004;34:1-6.
- Khan EA, Tyndall DA, Ludlow JB, et al. Proximal caries detection: Sirona Sidexis versus Kodak Ektaspeed Plus. Gen Dent. 2005;53:43-48.
- Schulte AG, Wittchen A, Stachniss V, et al. Approximal caries diagnosis after data import from different digital radiography systems: interobserver agreement and comparison to histological hard-tissue sections. Caries Res. 2008;42:57-61.
- Hintze H. Diagnostic accuracy of two software modalities for detection of caries lesions in digital radiographs from four dental systems. Dentomaxillofac Radiol. 2006;35:78-82.
- Castro VM, Katz JO, Hardman PK, et al. In vitro comparison of conventional film and direct digital imaging in the detection of approximal caries. Dentomaxillofac Radiol. 2007;36:138-142.
- Alkurt MT, Peker I, Bala O, et al. In vitro comparison of four different dental X-ray films and direct digital radiography for proximal caries detection. Oper Dent. 2007;32:504-509.
- Gakenheimer DC. The efficacy of a computerized caries detector in intraoral digital radiography. J Am Dent Assoc. 2002;133:883-890.
- Yoon DC, Wilensky GD, Neuhaus JA, et al, inventors; Logicon Inc, assignee. Quantitative dental caries detection system and method. US patent 5 742 700. April 21, 1998.
- US Food and Drug Administration, Center for Devices and Radiological Health. Device Approvals and Clearances: Logicon Caries Detector. PMA No. 980025. September 1998.
- Private communication between Dr. Stephen Miller and a patient via e-mail, May 26, 2008.
Disclosure: Dr. Miller lectures for and receives an honorarium for his teaching services from PracticeWorks.
Disclosure: Stephanie Lacina is presently an employee and the Product Specialist for Logicon Caries Detector for PracticeWorks Systems, a Carestream Health company.
Disclosure: Dr. Gakenheimer is presently an employee and the Product Line Manager for Logicon Caries Detector for PracticeWorks Systems, a Carestream Health company.
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