**3. Results**

Table 1 lists the measured the average carious lesion depths of 44 teeth on digital images (radiograps, RVG, and tomographic) and histologic observation.

The Bland-Altman plot test revealed that the percentage agreement between radiographic and histologic measurements was 93.2% while 6.8% of the points were beyond the ±2 (Std. Dev.) of the mean difference. On the other hand, 90.9% agreement were observed between both RVG and histologic measurement and volumetric CT and histologic measurement. 9.1% of the points were beyond the ±2 (SD) of the mean difference for both comparisons.


is comparable to the radiation from a single Panorex, while a dental CT scan is roughly

It is also possible to detect the relationship of the caries lesions with pulp chamber as 3-D. Therefore, the superpositions were eliminated with this system. The aim of this study was to compare the new dental volumetric tomography, RVG and conventional radiography in

Randomly chosen 44 extracted and unrestored premolars and molars teeth with appoximal carious lesions were embedded in silicone (Optosil- Bayer Dental, Leverkusen, FRG) blocks in sets of 4 (2 premolars and 2 molars in contact), simulating as far as possible their presumed anatomical relationships. Extra 3 posterior teeth (One of them with a 1 cm metal wire fixed on occlusal, the others drilled in depth of 3 mm round hole in proximal contacts)

D (Agfa Dentus M 2D, Germany) and E (Cea Dent, Ced D, Sweden) – speed radiographic films were used to take x-ray. Exposures were standardized at 18 impulses (0.3 s) from a model Kodak C6 320 FFD (70 kVp, 8 mA) radiation source (Kodak-Trophy ETX, France) that is also then integrated with the imaging system *(Kodak RVG 5000)* with distance of 20 cm holder device (short cone) (Dentsply Gendex Rinn, Milano, Italy). Films were processed immediately after exposure in fresh Kodak Readymatic processing solutions by means of a Velopex automatic temperature controlled processor (Extra-x, London, England). Processed radiographs were scanned to the computer for the measurement of carious lesions depths linearly in software. For the digital imaging, the sensor was fixed with the holder and

The NewTom (NewTom 9000; Quantitative Radiology, Verona, Italy) CBCT machine was used for the volumetric CT imaging. The teeth blocks were inserted to the centre of a water filled glass model have a volume to simulate a human head. Exposure was; 110 kVp, 5,2 mA for 36 s. The depth of carious lesions was measured linearly in software (NewTom 3G, generation 2). For the validation criteria, the roots of teeth were discarded and the crowns were sectioned as mesiodistally by a low speed diamond saw (Isomet 100 precission saw, Buchler, Germany) for histological measurements under the stereomicropcopy (Leica MZ 75, Heerbrugg, Germany). Bland-Altman plot test was used to describe agreement between software and histologic

Table 1 lists the measured the average carious lesion depths of 44 teeth on digital images

The Bland-Altman plot test revealed that the percentage agreement between radiographic and histologic measurements was 93.2% while 6.8% of the points were beyond the ±2 (Std. Dev.) of the mean difference. On the other hand, 90.9% agreement were observed between both RVG and histologic measurement and volumetric CT and histologic measurement. 9.1% of the points were beyond the ±2 (SD) of the mean difference for both comparisons.

equivalent to 6-8 times that amount, depending on bone density.

determination of the depth of approximal carious lesions.

were mounted for the calibration and control.

Trophy dental unit was exposured for the 0.18 s.

measurements of approximal carious lesion depths.

(radiograps, RVG, and tomographic) and histologic observation.

**3. Results** 

**2. Materials & methods** 


*\*(Bland-Altman analysis: Radiographic-histologic: 93.2%, RVG-histologic and Volumetric-histologic: 90.9%)* 

Table 1. Carious lesion depths (mm) measured linearly in software and histologically.

Volumetric Tomography in Determination the Caries 185

(a)

(b)

The present study has demonstrated that the volumetric tomography images have the

In the most of studies (Velders et al., 1996; Svanæs et al., 2000; Wenzel, 2001; Khan et al., 2004; Young & Featherstone, 2005), the proximal carious lesion was evaluated by using the visual criterion. Although the visual criterion used was somewhat subjective, it represented the best clinical representation of a proximal carious lesion. In previous similar in vitro studies (Jesse, 1999; Kooistra et al., 2005), the gold standard for comparisons was histological section of the extracted teeth. Caries depth was evaluated in these sections based solely on the microscopic evaluation of a color change between involved and uninvolved dentin.

The singular purpose of the radiographic capture device (DDR sensor or conventional film) is to capture the X-ray photon density pattern as it emerges from the subject tissues. The photon dispersion pattern that emerges from the tissues is a function of the tissues and the radiation source. An image would be sharper if the beam originated from a point source

potential to be the practical extraoral imaging modality for proximal caries detection.

Fig. 3. Photographs of conventional radiographs, D (a) and E (b) speed films.

**4. Discussion** 

The stereomicroscopy measurements revealed that the real caries depth was determined with the new volumetric tomography (fig.1) while RVG (fig.2) and similarly conventional radiography (fig.3) imaged less depth than it.

Histologic examination of the teeth confirmed that the dental volumetric CT also appears to be very promising in caries lesion imaging.

Fig. 1. Digital image of Volumetric CT.

Fig. 2. Digital image of RVG.

The stereomicroscopy measurements revealed that the real caries depth was determined with the new volumetric tomography (fig.1) while RVG (fig.2) and similarly conventional

Histologic examination of the teeth confirmed that the dental volumetric CT also appears to

radiography (fig.3) imaged less depth than it.

be very promising in caries lesion imaging.

Fig. 1. Digital image of Volumetric CT.

Fig. 2. Digital image of RVG.

(a)

(b)

Fig. 3. Photographs of conventional radiographs, D (a) and E (b) speed films.
