The anticipated result of this trial shall deliver information on the long-term effectiveness of caries infiltration and thereby result in an improvement in caries prevention within the scope of dental treatment, and prevent the progression of existing carious lesions . This is a micro-invasive form of treatment, which largely facilitates the delay or avoidance of conventional invasive initial dental treatment with the associated inevitable loss of healthy tooth structure. Further studies on the optimization of the infiltration technique can be built upon these results. In the long-term, it will be possible to use these findings to develop new prevention and treatment options for approximal carious lesion .