**Contemporary methods** [21]

1.Electrical conductance measurement (Caries meter L):

The tooth surface is inserted with conducting gel and is gently air-dried. Every tooth surface is dampened between the measurements to establish proper contact between the electrode and tooth surface. The device has colour codes to indicate the extent of caries as given in **Table 4**.


#### **Table 2.**

*Different systems for evaluation on clinical examination.*


**Table 3.** *Gorelick index scoring.* 2.Quantitative light fluorescence (QLF):

According to Rodrigues et al. in 2011, there are two devices used in QLF. They are DIAGNOdent device and DIAGNOdent pen. The device consists of a laser diode, photo diode and a long pass filter [27]. A tip is placed on the tooth surface at a certain angle and fluorescence values are calculated as in **Table 5**.

3.Light-emitting diode fluorescence:

LED fluorescence is based on the principle of difference in optical property. There are two available systems: Midwest caries (MID) and Vista Proof (VP). MID probe is a small battery-operated device with a portable handpiece and a probe [27]. When the probe touches the demineralized tooth surface there is an audible signal with a colour change from green to red as given in **Table 6**.

4.Frequency-domain infrared photothermal radiometry and modulated luminescence (PTR/LUM) [21]:

A recent technology called the Canary system has been introduced in the year 2011. This system consists of a laser tip along with an intra-oral camera. The laser tip is placed on the tooth surface that has to be examined and the WSL is recorded based on the scoring from 0 to 100 on the digital display. The scores and inferences are given in **Table 7**.


#### **Table 4.**

*Colour codes and inference of caries meter L.*


#### **Table 5.**

*Scoring of DIAGNOdent device.*


#### **Table 6.**

*Scoring of Midwest caries device (LED fluorescence).*

*White Spot Lesions and Remineralization DOI: http://dx.doi.org/10.5772/intechopen.101372*


**Table 7.**

*Scores and inference of PTR/LUM.*
