Alternative Method for Detection of Aproximal Caries

Occlusion of the occlusal caries to the proximal has been widely demonstrated in epidemiological studies. Unlike occlusal surfaces, the proximal surface can not be directly detected visually due to the presence of neighboring teeth. Therefore, the dentist relies on demineralization signs in the bitewing radiographic image as a support of clinical examination for early detection of aproximal caries.1



Recent meta-analysis studies have shown that visual and radiographic examination have high specificity but low sensitivity for early detection of aproximal caries. This suggests that conventional methods have a risk of developing non-cavity lesions causing irreversible tooth decay before lesions are detected.1

Based on searches from several in vitro and in vivo studies, various new methods have been proposed for aproximal caries detection as described below.11. Cone Beam Computed Tomography (CBCT)

It is a modification of Medical-CT that produces three-dimensional images. Several studies have reported the use of CBCT for enamel and dentine caries detection, compared with conventional methods, CBCT became the gold standard in aproximal caries detection because it has a higher sensitivity.2 However, the expensive cost makes this method difficult to apply in general in day-to- day.3

2. Fiber-Optic Trans-Illumination (FOTI) and Digital Imaging Fiber Optic Transillumination (DIFOTI)

FOTI is a simple technique that uses white light for dental transilumination. The FOTI principle shows the result of transillumination of demineralized enamel regions resulting in dark shadows due to changes in light scattering and the absorption of photon beams.4 Friedman and Marcus suggest this technique to detect caries. This method is also widely accepted as a valid method for detecting caries.5

DIFOTI has the same principle as PHOTI, and uses light for dental transilumination accompanied by a camera coupled charge device (CCD). The advantages of DIFOTI over bitewing radiography are low radiation, reducing the discomfort of patients due to sensors or film, higher sensitivity for early detection of caries.6

3. Near-Infrared Digital Imaging Transillumination (NIDIT)

Methods using the same transillumination principle as FOTI and DIFOTI were introduced in Europe in 2012 (DIAGNOcam, KaVo, Biberach, Germany) and in the United States in 2013 (CariVu, DEXIS, LLC, Hatfield, PA, USA). This device uses near infrared lights to transiluminate teeth. This system transmits light through the gingiva, alveolar bone, tooth root, and to crown.7

4. Optical Coherence Tomography (OCT)

It is a non-invasive, non-radiation technique that uses infrared light to produce a true cross-sectional view of the network. This tool constructs images from the backlight that is scattered from the transiluminated tissue, based on the difference in optical absorption and the scattering properties of tissue.8 This method has been widely used in the branch of medical science. In dentistry it is used for early caries detection, a cracked dental diagnosis, and assesses the marginal integrity of the restoration.9

5. Laser Fluorescence (LF)

Detection of caries LF (DIAGNOdent pen, KaVo) is based on the principle that when red light is directed at the teeth, caries-related changes in dental tissue lead to increased fluorescence.10 This fluorescence change is caused by protoporfyrin, the photosensitive pigment present in carious tissue due to metabolic activity bacteria.11 Healthy teeth produce little or no fluorescence, while carious teeth produce fluorescence proportional to caries level. LF also provides a value from the point of application that can be used to estimate the depth of the carious lesion.10

6. LED Fluorescence

This method detects a difference in the reflection and refraction of infrared energy from the red light-emitting diode (LED) carried by the fiber-optic cable to the tooth. The presence of a carious lesion will cause a change in this trait. Another fiber optic cable serves as a photodetector that transmits light captured to a microprocessor, comparing signals with specified parameters. The caries detection method based on this principle was introduced as Midwest Caries I.D. (Dentsply, York, PA, USA) .12

7. Ultrasound

Ultrasonography uses sound waves with a higher frequency than humans can hear. This frequency limit is approximately 20 kHz. Ultrasound imaging offers several advantages including simplicity, low cost, no harmful side effects, and images that are exactly the real conditions. For caries detection, ultrasonography is based on substantial differences in sonic conductivity between sound and demineralization of enamel. An in vitro study evaluated ultrasonic caries and radiographic detection equipment for proximal caries detection, with histology as the gold standard.13

8. Frequency-Domain infrared Photothermal Radiometry and Modulated Luminescence (PTR / LUM)

The manufacturer claims that the system can detect caries from 50 μm to 5 mm depth, including under sealant and around margin restoration, unaffected by stain or calculus. The caries detection method of PTR / LUM exhibits higher sensitivity and specificity than visual, radiographic, and LF examination for early occlusal caries detection. An in vitro study evaluated the performance of PTR / LUM, and was regarded as the gold standard for early detection of aproximal caries.14


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