Posterior_Direct_Restorations Salvatore_compressed

FIG 3-34 (a to d) Schematic and radiographic representation of the L&M classification.

A more recent classification, termed E-D, differs from the L&M classification in that it divides the dentin into thirds. Another difference lies in the fact that E indicates involvement of enamel and D indicates involvement of dentin, based on radiographic evidence of the caries lesion25–27 (Fig 3-35).

FIG 3-35 (a to e) Schematic and radiographic representation of the E-D classification.

It is legitimate to question the usefulness of a new classification. As already mentioned, and as will be seen later, a demineralized tooth tissue area does not necessarily mean cavitation is present. In vivo assessments carried out on patients27 show that the probability of cavitation being present in permanent teeth based on radiographic involvement (E-D classification) is as follows:

E1: 0%

E2: 10.5%

D1: 40.9%

D2 to D3: 100%

The importance of this more up-to-date classification is therefore immediately apparent: in the L&M classification, stage D3 also includes part of the central third of the dentin, which corresponds to stage D2 in the E-D classification. In the latter classification, D2 is always associated with cavitation. This is important because in the absence of cavitation, it is possible to consider minimally invasive intervention methods that do not necessarily require a classic restorative approach to the lesion.28

Laser fluorescence

Laser fluorescence is based on the use of a diode laser able to detect signs of cariogenic bacterial activity inside tooth grooves (Fig 3-36).20 This investigation method results in an easily recordable numeric score. It is particularly recommendable for regular checkups on suspect lesions in grooves, fossae, and foramina that are visibly inaccessible in low-risk patients, where a deep groove or early lesion that is no longer active is considered sound and therefore does not require restoration, only regular monitoring (see Fig 3-16). If the numeric score associated with the area in question remains consistently low and unchanged (or barely fluctuating) during these checkups, the area is likely to be free of caries activity. If the numeric score increases significantly compared with previous scores during regular checkups or an increasing trend is observed, the area under examination is more likely to be subject to caries activity.

FIG 3-36 Diode laser instrument.

The scores provided by the equipment range from 0 to 99, and the results can be interpreted as follows based on histologic investigations29:

0 to 5: Healthy tissue

6 to 14: Demineralization of the outer part of the enamel

15 to 20: Demineralization of the outer and inner part of the enamel 21 to 99: Lesion of the dentin

As with other diagnostic tests, laser fluorescence has its limitations21,29,30:

The reading is impaired when strong pigmentations, plaque, and/or calculus are present.

Where grooves are very deep, the laser beam may not be able to correctly interpret the lesion.

The examination can be impaired by excessive moisture or dehydration.

It is not very sensitive (risk of false positives). Equipment cost is high.

Limitations due to contaminants in the grooves can be reduced by always applying the same preparation protocol for the area to be analyzed. For example:

Cleaning of the surface with air flow of glycine or erythritol at different angles for 7 seconds (Fig 3-37)

FIG 3-37 Standardized cleaning stage.

Use of a prophylactic brush and glycine or erythritol powder (Fig 3-38)

FIG 3-38 Further cleaning using small rotating brushes coated with glycine powder.

Rinsing of the surface for 10 seconds

Drying of the surface for 5 seconds

Visual inspection and removal of any residue

Repetition of cleaning procedure until acceptable conditions are achieved

Transillumination

Fiber-optic transillumination (FOTI) is an effective aid in the identification of caries lesions because demineralized tissue interacts with light in a different way compared with healthy tissues.20 When used to detect interproximal lesions, a highintensity white light source31 is applied to the buccal or palatal surface and observed through the occlusal surface (posterior teeth) (Fig 3-39) or the surface opposite the light (anterior teeth). A dental curing light can be converted to a FOTI light by applying a special additional tip (Fig 3-40). Enamel lesions look like gray shadows, and dentinal lesions look orange or blue. Although data relating to the

sensitivity and specificity of this method are conflicting, there is plenty of evidence in the literature to support its use to detect interproximal lesions in both the anterior and posterior sectors,20,21 particularly when combined with the ICDAS II visual detection method, which can only benefit from this support. The FOTI technique, when combined with visual examination, is currently one of the most effective diagnostic systems. It can be used for anterior teeth but is not recommended for posterior sectors. The latter can be diagnosed using a digital system known as DiFOTI (digital imaging FOTI). This displays images on a screen in grayscale and stores them in the memory of the computer to which the system is connected (by means of dedicated software) (Fig 3-41). Unlike the FOTI technique, which can be performed using a simple and inexpensive fiber-optic lamp, DiFOTI requires more complex equipment as well as a computer and software for processing and storing images.

FIG 3-39 Caries lesions affecting the distal wall of a premolar identified using the FOTI technique.

FIG 3-40 A dental curing light can be converted to FOTI by applying an additional terminal.