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COMPARISON OF DIFFERENT METHODS OF EXCAVATION CONTROL FOR MINIMALLY INVASIVE CARIES TREATMENT

Table 7 . Changes in the colors of dentine of Group 4

HSB Level

H ( Hue ) 0 S ( Saturation ) % B ( Brightness ) % N Mean ± Std . Dev Mean ± Std . Dev Mean ± Std . Dev

1-st level 8 37.38 ± 3.02 23.38 ± 7.11 73.63 ± 5.29

2-nd level 8

36.75 ± 3.69

15.75 ± 8.12 75.88 ± 4.36 3-rd level 8 34.75 ± 4.74 11.38 ± 6.19 78.00 ± 3.67 Control 8 40.88 ± 4.22 6.63 ± 2.26 77.50 ± 4.11

say that in fluorescence control , affected dentine remains demineralized to a greater extent in the studied depth of 1 cm . Our results show another very interesting trend that “ non-infected dentine ” does not necessarily have the classical yellow characteristic of healthy dentine . The non-infected dentine , obtained by fluorescence control is partially demineralized and it must be preserved without the need of “ over excavation ” of dentine . A similar in vitro study was carried out by Benarjee et al . on 12 extracted carious molars . 3 , 22 Researches for micro hardness ( at Knoop ), emission of auto fluorescence signal [ using a confocal laser scanning microscope ], and digital photo images on the sliced surfaces of tooth samples in set points were conducted . The results obtained are used for direct comparisons between color , auto fluorescence and micro hardness of each lesion . The authors demonstrated that a correlation , which is not absolute , exists between the changes in the analyzed parameters . According to them , the transmission of fluorescent signal stops before reaching a dentinal layer , which micro hardness values are close to those typical for healthy dentine . This dentine layer is of a light yellow to

3 , 16 , 22

light brown color and a relative hardness . That allows researchers to propose the use of auto fluorescence signal emitted by carious lesions as an objective and reliable criteria for control during excavation . According to the results obtained in our previous study , 19 there is a reverse-proportional relationship between the color of the dentine and the intensity of the fluorescent signal . A similar conclusion , however for a correlation between the hardness of the dentine and intensity of the fluorescence signal is observed in other studies . 11 , 20 , 22 There is also evidence for in vivo studies demonstrating the close association and relationship between the texture and color of carious dentine and quantity 14 , 15

of microorganisms in it . The overall conclusion that can be drawn is that at the bottom of the excavated cavities , the remaining affected dentine differs in all 3 characteristics of the color , which is in the area of the brown tones and in depth hue changes to yellow , the saturation to low rates , which is indicative of a reduction in saturation and brightness changes in the direction of increasing the percentage ( towards white ). This indicates the presence of remaining demineralized dentine as the degree of demineralization decreases in depth when using the visual and tactile control and remains more uniformly demineralized when uniformly fluorescent control is used . Excavation to healthy dentine with visual and tactile-controlled method differs in color from “ non-infected dentine ” registered with the fluorescent control method , whose color is an indicator of a partial demineralization but with no microorganisms or microbial bio-products , which is a prerequisite for such dentine to be retained and it is preferred to over excavating to healthy dentine or reaching the underlying pulp . In the first case , the color is fairly close to the color of healthy controls , and the second is distinguished reliably from it .

5 . Conclusions

Our study shows that changes in the color of dentine registered by HSB system can be used as an objective method for monitoring the degree of demineralization in depth of the carious process in in vitro studies . The methods for excavation under the visual and tactile method for control provide inconsistent and non-satisfactory results : Mechanical excavation to affected dentine under the visual and tactile method for control leads to remaining of demineralized dentine up to the depth of 0.8 mm . The demineralization zone does not acquire the characteristics of healthy dentine , and cannot be defined as non-infected . In excavation to healthy dentine , the characteristics of dentine in depth match those of healthy dentine , but with high possibility of over excavation .