Cracked teeth are generally observed in dental practice and are always nightmare to the patients due to their unpredictable symptoms and diagnostic conundrum for the dental practitioner due to their variable and unusual clinical presentation. Cracked teeth are the common cause of tooth loss after periodontal diseases and caries. The treatment of diseases related to teeth are typically lengthy and include a considerable morbidity. Current teeth crack detection method includes optical assessment with or without the aid surgical loupes and microscopes etc. However, liquid penetrant test is one of the cheapest and easiest method of cracked teeth inspection. Penetrants are either visible dye penetrants of fluorescent dye penetrant. In this study, an investigation of the effectiveness of caries detection dye and fluorescence dyes for detection of cracked teeth has been conducted. The test results indicated that the dye penetrant liquid leaked into the small cracks and dents of the animal and human teeth and made those defects visible.