COMPARISON OF DIFFERENT METHODS OF EXCAVATION CONTROL FOR MINIMALLY INVASIVE CARIES TREATMENT
Figure 2. Hue / Saturation / Brightness( HSB) scheme
Figure 1. Scheme of the arrangement of the lines in the object of the analysis
- In the visual and tactile control method- yellow or light yellow dentine; hard consistency, slightly creaking and resistance when probing;- In the fluorescence control method with Facelight- pale red fluorescence disappears. Criteria for excavation up to affected dentine:- In the visual and tactile control method- dark yellow or light brown dentine; medium-hard consistency, a slight resistance when probing with a white trail;- In the fluorescence control method with Facelight- a weak pale red fluorescence only at the bottom of the cavity. The cavity preparation was conducted by one examiner and the evaluations were made by 3 examiners after preliminary calibration.
2.1. Preparation of extracted teeth for the experiment The extracted teeth used in this study were stored in a solution of distilled water with thymol. At least 24 hours prior to the excavation they were left in pure distilled water. After completion of the excavation and clinical assessments the roots were separated from the clinical crowns, then the samples were dried in alcohol solutions of increasing concentrations( 30 %, 70 %, 90 %). The cavities were isolated by restoration using temporary filling material( Adhesor, SpofaDental a. s. HQ, Jičín, Czech Republic). Then samples were packed with an epoxy resin in plastic cylinders 1.5 cm in diameter of and 3.5 cm in height. After resin polymerisation, the specimens were bisected in the axial axis of the tooth in the mesio-distal direction. Temporary restorations were removed from both halves, and then they were used for the purposes of that in vitro study about the applying of photographic equipment for dentinal changes characterisation during the excavation.
2.2. Original authors method Developing of methods for valuation of changes in dentine during excavation, using highly specialized digital photographic equipment and software:
Dental samples were documentary evidenced using highly specialised digital photographic equipment consisting of the following components: body- Nikon D90, lens- Nikon AF-S Micro-Nikkor 105mm f / 2.8G VR, flash- Nikon SB-R 200 Speed light Remote Kit R1( Nikon Corp., Tokyo, Japan). Photographing the objects was carried out under the following conditions- focal distance 105 mm, coefficient of approximation- 1: 1. The resulting images underwent software analysis of the color under the developed original methodology, as follows: First we put Line D- parallel to the enamel dentine junction. Then Line A- forming an angle of 94 ° with the line parallel to the enamel dentine junction and intersecting the pulp chamber, Line B and Line C- bisectors of the angle between Line A and Line D, were drawn. Three levels of depth were determined:- Level 1 – on the surface of the excavation- Level 2 – 80 pixels( 0,4 mm) down the non excavated dentine- Level 3 – 160 pixels( 0,8 mm) down the non excavated dentine The points where the three Lines cross the three Levels( Fig. 1) were analysed with the use of specialised digital software( Adobe Photoshop CS 5.5, Adobe Systems, San Jose, CA, USA). A randomly chosen point on the area of healthy dentine was used as control point. In each of the three points, as well as in the control point the color was measured for each parameter according to the color system- HSB( Hue, Saturation, and Brightness)( Fig. 2). HSB system is defined as a device-independent way for determining the color, i. e., once the color defined by this system; it can be reproduced isometrically by different devices. This system presents a color as a relationship of three parameters:- Hue- shade of color. Practically it is the color itself. Measured in linear degrees- 0- 360 °; 0 ° = red, 60 ° = yellow, 120 ° = green, etc.
- Saturation- color saturation. Measured in percentages-0 %= no color, 100 % = highest color intensity.
- Brightness- the brightness of the color. It is expressed in percentage of the black( 0 %) to white( 100 %).
Changes in the color of all points were used to
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