Standard caries diagnostic methods include a visual tactile method, as well as several radiographic methods. The former is a subjective method, while bitewing radiographs and digital radiographs (radiovisiography) enable detection of caries lesions only after 30% of hard dental tissue mineral substances have been lost. The paper presents methods based on electrical and optical phenomena that allow early caries diagnosis. Strengths and weaknesses of each presented method are discussed, basing this on recent literature review. The methods of caries detection generally used in daily clinical practice, combined with alternative methods, make it possible to significantly increase the effectiveness of dental caries diagnosis.