There is an ever increasing need for better, i.e. more sensitive and specified methods of caries diagnosis. Especially diagnosis of early caries when changes are reversible by remineralisation is crucial in preventive dentistry.

            Objectives: to evaluate sensitivity and specificity of visual examination, radiological method, diagnostic laser and impedance spectroscopy verified by histological examination.

            Methods: the study was conducted on occlusal surfaces of 48 extracted for orthodontic or periodontal reasons, not filled molars. The teeth were examined by visual examination (without magnification), radiological method ((Digora System), diagnostic laser device (Diagnodent) and ac impedance spectroscopy in two-electrode system in the range of frequeny from 100 to 400 KHz. An Autolab 30 Analyser linked to a PC was used to carry out the impedance measurements and to collect the data. Obtained data were analysed by means of the software Zplot and Zview.

Agreement between two independent examiners – κ value was counted for every examined method and it oscillated from 0.72 to 1 depending on the method.

After all measurements were completed 40 μm thick tooth sections were examined using light microscope (Olimpus BX 50). Demineralisation depth in enamel and dentin was evaluated.

Obtained results were subjected to statistical analysis using U Mann-Whitney and Wilcoxon tests.

Results: are presented in the table.

	METHODS
	Visual examination	Diagnodent	Radiological examination	Impedance spectroscopy
				T	Rb	j
SENSITIVITY	71,0%	93.5%	48.4%	77.4%	67.7%	100%
SENSITIVITY for early caries changes	50%	87.5%	12.5%	56.3%	37.5%	100%
SPECIFICITY	88.2%	94.1%	100%	100%	100%	100%

 

Conclusion: on the basis of the obtained results it can be concluded that parameter j (phase angle) of the impedance method has the highest sensitivity (100%) and specificity (100%).