The Canary System is the Anchor for an Office Prevention Program

In early December,a study was published in Community Dentistry and Oral Epidemiology looking at the outcomes from 1,000 patients in 22 dental practices at the University of Sydney in Australia that were involved in a preventive program. The conclusions are not surprising in that some preventive / remineralization programs can prevent or halt the growth of caries. What is challenging is how they measured outcomes over the long term.

The key to a successful preventive / remineralization program, is to engage the patient in changing behaviours and using the appropriate tools for remineralizing these early lesions. The other important element is to provide the dental team with an instrument or device to measure changes in lesion size or volume over time.

Currently we rely upon visual examination and radiographs to detect lesions and try to monitor their progress. This has many challenges especially since a lesion may be increasing in size beneath the tooth surface while it continues to exhibit a brown or white stain on the tooth surface. Radiographs are not capable of measuring subtle lesion volume changes in interproximal region and can’t detect smooth surface lesions. Many times in clinical practice I had used the “latest” preventive home and office therapy only to find that 2 years later cavitation had developed. During this time the lesion did not change visually and we tried to ascertain whether the patients were following our home care advice.

The Canary System is the only device that can detect and measure caries on all tooth surfaces and around the margins of restorations. It measures changes in the crystal structure of the tooth and not fluorescence or glow from stain or oral bacteria on the tooth surface. This allows the dental team to detect lesions and monitor their response to various preventive therapies. In developing our system we also created patient reports and audible readings so that patients can become actively involved in their preventive care. In our two clinical trials and from discussions with our users, we find that patients are more engaged in their care when they can become involved in monitoring their progress. Having a device to provide a measurement, a scale that patients understand and audible and printed reports we find, gets the patients involved in their care and we get much better compliance in the long term.

Visit the company web site for more information.

Caries Detection: Issues to Consider Before Purchasing Systems

Caries detection is a very interesting, important and evolving area in clinical dentistry. Caries is one of the major diseases dentist detect and treat.  Our current tools do present some challenges.  X-Ray and visual exam were introduced in the last century and really are designed to detect very large lesions.

There are some issues to consider before purchasing a system.  The first is to consider what is the particular device detecting and how does it do it?

Visual and radiography are considered the gold standard for caries detection but they have significant limitations. Visual exam obviously only shows surface changes and sub-surface shadowing, if there is a large stained lesion.

•  Radiographs are good for detecting large interproximal caries (at least halfway into enamel) but they are only providing a 2-dimensional view of the lesion and the surrounding tooth structure or restorations will mask the lesion. There are a number of case studies on our web site which illustrate the shortcomings of dental radiographs.

DIAGNODent, Spectra, QLF and SOPRO are all fluorescence devices and they detect fluorescence or “glow” from bacterial porphyrins or stain and not anything related to the tooth surface, cracks or caries. Most of the fluorescence does not come from Strep Mutans or Lactobacillus organisms but from other bacterial found in the oral cavity.

CARIVU is simply trans-illumination much like we did with visible light over 40 years ago. The difference is that the system uses infra-red to illuminate the tooth. This will find caries in the interproximal region and larger lesions on the walls of some restorations but they are still relying upon visual inspection of the image. When one moves to smooth surface or detecting caries around restoration margins or pits and fissures, trans-illumination is challenged.

The Canary System uses laser based energy conversion technology to examine and measure the status of the tooth crystal structure. It can detect caries on all tooth surfaces, around the intact margins of restorations and beneath sealants. Since it can measure changes in tooth crystal structure, we have used it in clinical trials to monitor changes in lesions when treated with various preventive therapies. The latest human clinical trial done at the University of Texas compared Canary to digital radiography. They found that The Canary System detected 92% of the lesions whereas radiographs found 67% of the lesions. Most of our research papers and publications are on our web site and we continue to release data as do other researchers working independently with our system.

I would recommend that before one “dives” into this market that they look carefully at what and how these systems work and the research backing each of the claims. In my opinion these are the ideal characteristics for a caries detection system:

1. High sensitivity & specificity for caries detection
2. Detects & monitors de & re-mineralization
3. Detects smooth surface, root surface, occlusal surface & interproximal lesions
4. Detects caries around restoration margins
5. Non-invasive & safe
6. Repeatable measurements
7. Imaging and or image capture
8. System for recording & storing measurements
9. Patient Education and Motivation
10. In-vitro and in-vivo data & publications including clinical trial data demonstrating the ability of the system to detect and monitor carious lesions
11. Minimal or no preparation of the tooth surface prior to taking a reading
12. Ability to detect and monitor erosion lesions

The key is to understand what the device is measuring.

 In reviewing a number of the devices on market, their research is weak and if present, the experimental design is not great.

We do need to move away from visual exam and radiography for detection, monitoring and management of caries. The key is to find the right device to provide you with the appropriate clinical information.

Disclosure:  Dr. Stephen Abrams is President Quantum Dental Technologies – The Canary System.

The Canary System is More Accurate Than X-Rays for Detecting Proximal Caries

Just published in the Journal of Investigative and Clinical Dentistry on May 27, 2015:

Proximal caries lesion detection using the Canary Caries Detection System: an in vitro study

 Authors:  Janja Jan, Wan Zaripah Wan Bakar, Sapna M. Mathews, Linda O. Okoye, Benjamin R. Ehler, Christopher Louden, Bennett T. Amaechi


Objective:  This study investigated the accuracy of the Canary System (CS) to detect proximal caries lesions in vitro, and compared it with conventional methods: International Caries Detection and Assessment System (ICDAS) II and bitewing radiography (BW).

Methods:  Visible proximal surfaces of extracted human teeth were assessed by ICDAS-II before setting them in five manikin mouth models. Then contacting proximal surfaces in mouth models were assessed by BW and CS. Histological validation with polarized-light microscopy served as a gold standard. Pairwise comparisons were performed on area under the curve (AUC), sensitivity, and specificity of the three methods, and corrected using Bonferroni’s method. Sensitivities and specificities were compared using a test of proportions and AUC values were compared using DeLong’s method.

Results:  The CS presented significantly higher sensitivity (0.933) than ICDAS-II (0.733, P = 0.01) and BW (0.267, P < 0.001), and ICDAS-II higher sensitivity than BW (P < 0.001). There were no significant differences between their specificity values: 0.825 (CS), 0.65 (ICDAS-II), and 0.875 (BW). The AUC of CS (0.862) was significantly higher than of ICDAS-II (0.681, P < 0.001) and BW (0.577, P < 0.001).

Conclusion:  The Canary System demonstrated greater accuracy in detecting proximal lesions than ICDAS-II (visual exam) and BiteWing X-Rays, although without significantly higher specificity.

So what does this all mean?  This study done on extracted teeth concludes that The Canary System is more accurate than the current gold standard, x-rays, for detecting caries between teeth.  X-Rays are only designed for detecting decay on this one surface while The Canary System can detect decay on all tooth surfaces, beneath opaque sealants and around and beneath the intact margins of crowns and fillings.

The Canary System is the solution for the detection and monitoring of tooth decay.

Are X-Rays and Visual Exams The Best Tools for Detecting Tooth Decay?

Can Radiographs and Visual Exam Detect Pit and Fissure Caries?

Radiographic and visual examinations are satisfactory if there is a substantial cavitated lesion.  Detecting early pit and fissure caries is challenging.  Radiographic imaging is of minimal diagnostic value because of the large amounts of surrounding enamel[i] [ii].  A number of studies have found the dental explorer inefficient for the diagnosis of occlusal caries.[iii] [iv]  There are a number of the concerns with the use of the explorer in detecting pit and fissure caries:

  • Since cavitation in pit and fissure caries occurs late in the disease process, using an explorer stick to detect caries only finds larger lesions,
  • Probing an occlusal pit or fissure could convert a small lesion into a larger one[v],
  • The probing could produce irreversible traumatic defects in areas that have the potential to remineralize,
  • Probing can inoculate the fissure with microorganisms from other intraoral sites[vi] [vii],
  • A stick or catch with an explorer may be due to fissure morphology or probe pressure rather than a carious lesion.

Can Radiographs Detect Enamel Lesions in Interproximal Areas (Between Teeth)?

Radiographs do perform well in detecting carious lesions in interproximal areas, especially if the area of decay is at least half way through the enamel or into dentin   In terms of early lesion detection, radiographs are not able to detect small lesions in the order of 50 – 100 μ (microns) in the interproximal areas, which could remineralize if detected early and suitable preventive measures instituted[viii].   One study using bitewing radiographs for detection of interproximal caries found 10.6% of enamel caries, 17.8% of dentine caries and 40.2% of deep dentine caries.  This indicated that at best bitewing radiographs could detect deep lesions less than 50% of the time[ix].  This low sensitivity for detection of enamel lesions in interproximal regions is not unusual and may be due to the irregular shape and low contrast of these small early lesions[x].

An extensive review of the literature by Dove[xi] found that “overall the strength of the evidence for radiographic methods for the detection of dental caries is poor for all types of lesion on proximal and occlusal surfaces”.  He further stated that “it is beneficial only if the intervention is the surgical removal of tooth structure and detrimental if it is used for non-invasive remineralization methods”.  Pretty and Maupome in their review of radiographic diagnostic procedures concluded that “for interproximal lesions a clinician using radiographs can be very certain of the lack of disease in apparently sound surfaces (97% specificity) but not as certain that disease is indeed present in suspect interproximal surfaces (54% sensitivity)”[xii].  Radiographs and visual examination are a valid diagnostic tool for the detection of larger lesions[xiii] [xiv] but there is need for more sensitive methods.

X-Rays are a good screening tool for looking at the bone level around teeth or at the edges of deep fillings below the gum line but they do have limitations.   X-Rays and Visual Exam are still common and standard tools for detecting tooth decay but one needs to look at the crystal structure of the tooth in order to detect and measure tooth decay or defects in teeth.  The Canary System offers the solution.

A recent clinical trial led by the University of Texas found that The Canary System found 92% of the decay between teeth while x-rays only found 62% of the lesions.  This study was reported at the March 2015 meeting of the International Association of Dental Research.

Visit for more information.

[i]  McKnight-Hanes C, Myers DR, Dushku JC, Thompson WO, Durham LC. “Radiographic recommendations for the primary dentition: comparison of general dentists and pediatric dentists”. Pediatr Dent. 1990 Jul-Aug;12(4):212-216

[ii]  Flaitz CM, Hicks MJ, Silverston LM. Radiographic, histologic, and electronic comparison of basic mode videoprints with bitewing radiography. Caries Res. 1993; 27(1): 65-70.

[iii]  Penning C, van Amerongen JP, et al, “Validity of probing for fissure caries diagnosis. Caries Res 26:445-9, 1992

[iv]  Lussi A, “Comparison of different methods for the diagnosis of fissure caries without cavitation”. Caries Res 27:409-16, 1993

[v]  Yassin OM. In vitro studies of the effect of a dental explorer on the formation of an artificial carious lesion.” ASDC J Dent Child. 1995 Mar-Apr;62(2):111-117

[vi] Ekstrand K, Qvist V, Thylstrup, A, “Light microscopic study of the effect of probing in occlusal surfaces”:, Caries Research, 1987; 21: 368 – 374

[vii] Penning C, Van Amerongen JP, Seef RE, ten Cate, JM “Validity of probing for fissure caries diagnosis”, Caries Research, 1992; 26(6): 445 – 449

[viii] Backer DO, “Post-eruptive changes in dental enamel”, J Dent Res 1966; 45: 503 – 51

[ix] Senel, B., K Kamburoglu, K., Ücok, Ö., Yüksel S. P., Özen, T., Avsever, H., “Diagnostic accuracy of different imaging modalities in detection of proximal caries”,  Dentomaxillofacial Radiology (2010) 39, 501–511

[x] Pontual A. A., de Melo, D. P., de Almeida, S. M., Boscolo, F. N., Haiter Neto, F., “Comparison of digital systems and conventional dental film for the detection of approximal enamel caries”,  Dentomaxillofacial Radiology (2010) 39, 431–436

[xi] Dove, S. B., “Radiographic Diagnosis of Dental Caries in Consensus Conference on Dental Caries Management Throughout Life, March 2001, Journal of Dental Education, 2001; 65 (10): 985 – 990

[xii]  Pretty, I. A., Maupome, G., “A Closer Look at Diagnosis in Clinical Dental Practice:  Part 3. Effectiveness of Radiographic Diagnostic Procedures”, JCDA, 2004; 70(6): 388 – 394

[xiii] Li, G., Yoshiura, K., Welander, U., Shi, X-Q McDavid W. D., “Detection of approximal caries in digital radiographs before and after correction for attenuation and visual response. An in vitro study”,  Dentomaxillofacial Radiology (2002) 31, 113 – 116

[xiv] Rockenbach, M. I., Bauer, E., Nilza, V., da Costa, P., “Detection of proximal caries in conventional and digital radiographs: an in vitro study”,  Stomatologija, Baltic Dental and Maxillofacial Journal, 10: 115-120, 2008

Healing Tooth Decay

Healing tooth decay; what a novel idea!  Aren’t oral health care providers already doing this?  Isn’t the placement of a restoration healing dental caries?  Not really. Restoring the effects of tooth decay by restoring a tooth is not really “healing” the tooth. It is treating the after effects of the disease.  Healing is defined as curing, helping to heal or growing back sound tissue.  One could argue that dental restorations do restore tissue but are we really healing dental caries or could we possibly heal caries by actually re-crystallizing or remineralizing the damaged enamel surface?  The answer is yes, we are already doing this but there are new techniques and approaches that can help us.

The key is to find the right system to monitor tooth decay or dental caries and then the right combination of preventive or remineralization products to actually stabilize or re-crystalize early areas of tooth decay.

The Canary System is the only system on market that can monitor changes in the tooth crystal structure.  It can become the anchor in a dental preventive program to monitor therapeutic outcomes.

Lots more information to share in the next few blogs.

What Causes Dental Caries or Tooth Decay and Can it Be Reversed?

Dental caries or tooth decay is a disease that results in the destruction of tooth structure.  It arises from an overgrowth of specific bacteria that can metabolize fermentable carbohydrates and generate acids as waste products of their metabolism.  Streptococci mutans and Lactobacillus are the two principal species of bacteria involved in dental caries and are found in the plaque biofilm on the tooth surface [i] [ii] [iii].  When these bacteria produce acids, the acids diffuse into tooth enamel, cementum or dentin and dissolve or partially dissolve the mineral from crystals below the surface of the tooth.  If the mineral dissolution is not halted or reversed, the early subsurface lesion becomes a “cavity”.  

The tooth surface undergoes demineralization (breakdown) and remineralization continuously, with some reversibility.  When exposed to acids, the hydroxyapatite crystals dissolve to release calcium and phosphate into the solution between the crystals.  These ions diffuse out of the tooth leading to the formation of the initial carious lesion.  The reversal of this process is remineralization.  Remineralization will occur if the acid in the plaque is buffered by saliva, allowing calcium and phosphate present primarily in saliva to flow back into the tooth and form new mineral on the partially dissolved subsurface crystal remnants[iv].  The new “veneer” on the surface of the crystal is much more resistant to subsequent acid attack, especially if it is formed in the presence of sufficient fluoride.  The balance between demineralization and remineralization is determined by a number of factors.  Featherstone describes this as the “Caries Balance”, or the balance between protective and pathological factors [v].   

These early lesions (both enamel and root surface) typically have an intact hard outer surface with subsurface demineralization.  The tooth surface remains intact because remineralization occurs preferentially at the surface due to increased levels of calcium and phosphate ions.  The clinical characteristics of these early carious lesions include:

  • Loss of normal translucency of the enamel resulting in a chalky white appearance particularly when dehydrated,
  • Fragile surface layer susceptible to damage from probing, particularly in the pits and fissures,
  • Increased porosity, particularly of the subsurface, with increased potential for uptake of stain,
  • Reduced density of the subsurface, which may be detectable radiographically (depending upon mineral loss and location) or with transillumination (depending upon location and loss of mineral),
  • Potential for remineralization with increased resistance to further acid challenge particularly with the use of enhanced remineralization treatments[viii].
In summary, bacteria consume sugars and produce acids which then breakdown the tooth surface.  In the early stages of this disease, the lesions may be remineralized or re-crystalized depending upon the conditions on the tooth surface and in the mouth.  These early lesions may appear as chalky white spots.  They may be fragile and crystal structure may be disrupted or destroyed if they are picked or probed.  This dynamic disease process can be reversed or stabilized if detected early. 
More to follow. 

[i]  Van Houte, J., “Bacterial specificity in the etiology of dental caries”, Int. Dent. J., 1980; 30: 305 – 326 

[ii] Van Houte, J., “Role of Microorganism in the caries etiology”, J. Dent. Res., 1994; 73:  672- 681 

[iii] Featherstone, J. D. B., “The Caries Balance:  Contributing Factors and Early Detection”, CDA Journal, 2003; 13 (2): 129 – 133 

[iv] Melberg, J. R., “Remineralization:  A status report for the American Journal of Dentistry, Part 1, Am J. Dent., 1988; 1 (1): 39 – 43 

[v] Featherstone, J. D. B., “The Science and Practice of Caries Prevention”, JADA, 2000; 131: 887 – 899  

[viii]   Mount, G. J., “Defining, Classifying, and Placing Incipient Caries Lesions in Perspective”, Dent Clin N. Am, 2005, Volume 49, pages 701 – 723


What is Tooth Decay or Dental Caries?

Dental caries or tooth decay, according to the United States Surgeon General report on Oral Health in America, is one of the most common chronic diseases among five to seventeen year olds[i].  In their study, it was more common than asthma, hay fever or chronic bronchitis.  Although we do not have this type of data available in Canada, one can assume that dental caries is extremely prevalent in the population.  A great deal of a general dental practitioner’s time is spent treating dental caries.  The dental profession’s understanding of caries and treatment approach has been evolving as new diagnostic devices and preventive techniques are introduced to our practices.  In 2001, the National Institute of Health’s (NIH) Consensus Conference on the Diagnosis and Management of Dental Caries throughout Life concluded:

“Dental caries is an infectious, communicable disease resulting in destruction of tooth structure by acid-forming bacteria found in dental plaque, an intraoral biofilm, in the presence of sugar.  The infection results in the loss of tooth minerals that begins with the outer surface of the tooth and can progress through the dentin to the pulp, ultimately compromising the vitality of the tooth.”[ii]

 This statement combines a number of new components from the traditional approach taught over the last twenty years in dental schools.  Our patients assume that tooth decay is caused by eating sugary foods, not that dental caries is an infectious communicable disease caused by acid forming bacteria.  One can place a number of restorations in a mouth, without treating the underlying disease.  The bacteria remain in the plaque biofilm on the remainder of the teeth capable of creating new areas of decalcification and cavitation.  Patients are beginning to expect that we can treat this disease or at least provide them with a reason as to why they or their children continue to develop carious lesions.

Over the next few blogs, I hope to provide you with some information on tooth decay, methods for detection and things patients and dentists can do to prevent decay or minimize the destruction of the tooth. 

[i] Department of Health and Human Services, “Oral Health in America:  A Report of the Surgeon General”, National Institute of Dental and Craniofacial Research, 2000, page 63 

[ii] “NIH Consensus Development Conference on Diagnosis and Management of Dental Caries Throughout Life March 26 – 28 2001”, Journal of Dental Education, Volume 65, # 10, 2001, page 1162