Advances in caries management: how improvements in technology have affected dentistry's approach to managing tooth structures.

CARIES DETECTION TECHNOLOGY

During most of the 20th century, if changes in the hard surface of the tooth were detected they were either "watched" or treated surgically. During the past few decades, a better understanding of the process of demineralization and scientific developments in diagnostic systems and dental materials has facilitated change in dentistry's approach to the management of demineralized lesions. The "minimally invasive" approach to treating demineralized lesions incorporates detecting, diagnosing, and treating these areas earlier, and employing more of a medical model than the traditional surgical model. Dental assistants should understand this approach in order to take a more active role in caries prevention and treatment.

TRADITIONAL CARIES DETECTION

Until recently, we have relied upon visual, tactile, and radiographic techniques to detect changes in tooth structure. We look at color, translucency, and hardness using relatively crude instruments such as explorers and radiographs to make decisions about the extent of the changes to the tooth surface and to guide us to the best treatment decisions. (1) In general, this approach has low sensitivity and high specificity, meaning a large number of early lesions may be missed. (2)

Sensitivity is the probability that a test will correctly identify the presence of a specific condition, or in this case the probability that the test will detect changes in the tooth structure; that it will detect demineralization. Low sensitivity can miss significant amounts of decay or produce false negatives.

Specificity is the probability that a test will correctly identify the absence of a specific condition, or in this case it will correctly recognize sound enamel as sound. Low specificity may produce false positives.

Reliability is the dependability or consistency of a measurement method. Quality of radiographs taken, lighting, and amount of pressure applied with an explorer all impact the reliability of these traditional methods of detection.

EARLY CARIES DETECTION

A limitation that can affect decisions to restore rather than monitor changes to the tooth structure over time is the ability to detect the earliest signs of disease. The accuracy of dental radiographs and visual inspection when used for demineralization (caries) detection is insufficient. (3) Research is ongoing to improve methods of early caries detection to allow us to fully implement new approaches to the management of dental caries.

Since the 1990s, the introduction of innovative technologies has expanded the opportunities to practice early intervention of these lesions. Adjunctive detection methods available to dental practitioners include:

Digital fiber-optic transillumination: Clinicians have routinely used transillumination to identify lesions located on the interproximal surfaces of anterior teeth. A digital fiber-optic transillumination instrument, now commercially available, uses safe white light to transilluminate the tooth surface and an image relay mirror and camera to display the image on the computer monitor. This technology images all (occlusal, interproximal and smooth) coronal tooth surfaces.

Infrared fluorescence. Infrared fluorescence measures reflected light, or laser fluorescence, of the tooth structure. A two-way optic device quantifies the reflected laser light energy. Clean, healthy tooth structures reveal little to no fluorescence. Increased fluorescence reflects greater amounts of bacterial materials and is an indication of caries.

Red-infrared reflectance technology is commercially available as the Midwest Caries I.D.[TM] (www.cariesid.com). This hand-held device uses infrared and red light emitting diodes (LED) and fiber optics to distribute light to the tooth structure (Figure 1, right). This technology detects mineral loss in enamel by measuring the light reflectance and refracation difference of infrared light on decalcified enamel as compared to healthy enamel. The device helps detect demineralized lesions earlier in the process, allowing for more conservative treatment.

Infrared light travels into the enamel as if it were relatively transparent. When the light hits demineralized enamel, it is scattered and attenuated, a detection fiber optic collects light from the examined area and sends that light to a photo-detector that measures returned collected light. This photo-detector then transmits the signal to a microprocessor that compares signal levels with defined parameters. When healthy tooth substance is detected, the green LED stays on resulting in a nonred color illuminating the tooth (Figure 2, left). When demineralization is detected, the processor deactivates the third LED (green), illuminating only the red LED, and pulses at a higher intensity (Figure 3, left). The lesion is identified by an audible tone, and a visual signal (red or nonred) on the tooth. The intensity or speed of the beep is proportional to the extent of demineralization. This device can be used on a wet surface and seems to offer hope for achieving reliable, accurate detection of the earliest stages of enamel demineralization.

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Dental teams should be resolute in early intervention to promote health, as opposed to focusing solely on treatment of disease. The practice of performing comprehensive risk assessments and dental examinations allows early detection of changes in tooth structure in time to intervene prior to the need for surgical treatment. In addition, dental professionals should strive to provide true prevention, where possible, with programs designed to disrupt or reduce the transmission of caries-causing bacteria and improve the resistance of the tooth structure to acid attack.

CARIES MANAGEMENT

Conservative Caries Management

The ideal outcome of conservative caries management is to preserve tooth structure and reduce the number of decayed and surgically treated teeth. The guiding principles are to:

* Assess the individual risk for caries.

* Detect demineralized tooth structure early enough so that the early, noncavitated lesion can be reversed or at least arrested from progressing by chemical means rather than by surgical intervention (placing fillings),

* Use fluoride and other agents to enhance remineralization.

* Reduce the bacterial challenge by the use of antibacterial therapy.

* Use minimally invasive restorative procedures to conserve tooth structure.

The longevity of the tooth is much greater in the conservative caries management model; many more teeth are preserved as caries-free. Those teeth that require restorative work have much smaller restorations leading to fewer fractures in the long term. (4)

Caries Management by Risk Assessment (CAMBA)

CAMBRA or Caries Management by Risk Assessment is a method of assessing caries risk and making dental treatment recommendations based on a patient's caries risk. Risk assessment forms are an instrument for dental professionals to record disease indicators and risk factors such as number of carious lesions in the past three years, current bacterial challenge, caries history, dietary habits, current prescription medications, saliva flow, medical conditions, and oral hygiene habits. Completion of a risk assessment form and determination of the level of risk for each patient is critical to making treatment recommendations based on the patient's level of risk. (5)

Every team member should understand the role a thorough risk assessment plays in the treatment planning process. Once a patient's risk has been identified as low, moderate, or high, the team can make evidence-based decisions on the appropriate therapy for that patient. The treatment plan, including use of antimicrobials, fluoride, sealants, the frequency of radiographs and periodic oral exams will all be determined by the caries risk level of the patient and knowledge of the contributing risk factors for that patient. (6)

THERAPY FOR REMINERALIZATION

We now understand more about the demineralization/remineralization process than ever before. This better understanding offers the opportunity to preempt cavitation of demineralized lesions and intervene at a much earlier stage, offering a different type of treatment. This is a paradigm shift from the traditional way of treating the disease. This opportunity presents us with an obligation to understand what products are currently available to assist the clinician in sound recommendations for patient interventions. (7)

For many years fluoride has been considered the primary treatment to remineralize early carious lesions. Fluoride reduces decay by helping to prevent demineralization and by remineralizing early lesions. Caries is a dynamic process that can be characterized by mineral transfer, from the tooth to the surrounding environment (demineralization) and from the surrounding environment to the tooth (remineralization). (8)

The key is to reduce mineral transfer out of the tooth during acid attacks, and to promote transfer into the tooth following acid attacks. This can be achieved by ensuring the availability of fluoride, calcium and phosphate adjacent to the tooth during and after an acid attack.

Several products are now available to slow the progression of caries and remineralize enamel subsurface lesions. It has been suggested that casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) reduces mineral transfer out of the tooth during acid attacks. However, very few clinical studies have been published comparing the effectiveness of CPP-ACP, thus, scientific evidence for its clinical effectiveness on remineralization is not yet available. (8)

Bioactive glass materials have been used in medicine and dentistry for years. This unique material (NovaMin[R]) has numerous novel features, including the ability to act as a biomimetic mineralizer, matching the body's own mineralizing traits, while also affecting cell signals in a way that benefits the restoration of tissue structure and function. Bioactive glass is considered a breakthrough advance in remineralization technology. This is because the current standard treatment for tooth remineralization and prevention of decay is slow acting and is dependent on adequate saliva as a source of calcium and phosphorus.

NovaMin[R], when in contact with saliva or water, first releases sodium ions. This elevates the pH into the range essential for hydroxyapatite formation (7.5-8.5). The calcium and phosphate are released to supplement the normal levels found in saliva. This increase in ionic concentration, combined with an increase in pH, causes the ions to precipitate onto the tooth surface and form calcium hydroxycarbonate apatite (HCA) to remineralize the defect and to occlude open tubules. Studies have shown that this new mineral is a form of crystalline hydroxyapatite that is just like natural tooth mineral.

An in vitro study demonstrated that treatment with a NovaMin[R]--containing prescription fluoride dentifrice improved hardening of white-spot lesions compared to fluoride-only dentifrice. From that study) preliminary data also indicated that NovaMin[R]--containing fluoride dentifrices have greater potential to remineralize and repair whitespot lesions than fluoride--only dentifrices. (9) An additional in vitro study indicated that incorporation of NovaMin[R] into fluoride dentifrices could arrest the tooth decay process earlier than currently available fluoride dentifrices. (10)

NovaMin[R] is found in two new NUPRO[R] NUSolutions[TM] products. NUPRO[R] NUSolutions[TM] Prophy Paste delivers the benefits of tooth desensitization, tubular occlusion and stain removal; it integrates a desensitization treatment into standard prophy treatment. NUPRO[R] NUSolutions[TM] Remineralizing and Desensitizing Take-Home Paste contains 5% NovaMin[R] and 5000 ppm sodium fluoride for the prevention of caries and the relief of tooth sensitivity.

CONCLUSION

As our profession and professional knowledge continues to evolve, our diagnostic procedures, techniques and therapeutic options will follow. We owe it to our patients and to ourselves to continue to evolve in an effort to provide the very best care. Dental health care providers now have the ability to address the infectious agents causing caries; we can now eliminate or reduce their effect rather than surgically removing the damage created.

The goal is to implement the technologies and products for prevention, early detection and intervention such as fluoride varnish, dental sealants, caries detection devices, and remineralization treatment that will ultimately result in conservative, long-lasting dentistry. The dental assistant can be instrumental in bringing these new technologies to day-to-day clinical practice.

REFERENCES:

(1.) Lussi A. Validity of diagnostic and treatment decisions of fissure caries. Caries Res 1991; 25(4): 296-303.

(2.) Ismail AI. Visual and Visuo-tactile Detection of Dental Caries. J Dent Res 83(Spec Iss C):C56-C66, 2004.

(3.) B. Nyvad. Diagnosis versus Detection of Caries. Caries Res 2004;38:192-98.

(4.) Tyas MJ, Anusavice KJ, Frencken JE, Mount GJ. Minimal intervention dentistry: a review. FDI Commission Project 1-97. Int Dent J 2000;50(1):1-12.

(5.) Featherstone JD. The caries balance: contributing factors and early detection. J Calif Dent Assoc 2003;31(2):129-33.

(6.) Jenson L, et al. Clinical Protocols for Caries Management by Risk Assessment. J Calif Dent Assoc 2003:35 (10):714-23.

(7.) Spolsky VW, Black BP, Jenson L. Products--old, new, and emerging. J Calif Dent Assoc. 2007 Oct;35(10):724-37.

(8.) Azarpazhooh A, Limeback H. Clinical Efficacy of Casein Derivatives: A Systematic Review of the Literature. J Am Dent Assoc 2008; 139; 915-24.

(9.) Burwell AK. Improved Healing of White Spot Lesions in Vitro. J Dent Res 87 (Spec Iss B): 0109, 2008 (www.dentalresearch.org).

(10.) Alaudin SS, Fontana M. Evaluation of NovaMin[R] as an adjunct to fluoride for caries lesion remineralization. NovaMin Research Report. Available at: http://www. novamin.com/pdf/research_reports/Evaluation_of NovaMin.pdf. Accessed April 13, 2009.

Karen Hays, RDH, BS, is the Western Clinical Educator for DENTSPLY Professional. She has over 20 years of experience in dentistry, including teaching both clinical Dental Hygiene at Chabot Community College and Dental Assisting at Heald College. She has published articles and held local positions in the California Dental Hygiene Association. Karen graduated in 1985 from Gulf Coast Community College in Florida as a Certified Dental Assistant and in 1993 from Pensacola Junior College with an Associate of Science degree in Dental Hygiene. She completed her bachelor's degree in dental hygiene at the University of Bridgeport Fones School of Dental Hygiene. Karen has developed and presented educational programs to dental and dental hygiene students, professional associations, dental societies and study clubs.