O ne of the factors causing the failure of tooth restoration is the forming of the secondary caries surrounding the restoration which is caused by the microorganism activities happening in between the restoration materials and teeth. The microorganism which become the primary cause of caries or secondary caries is Streptococcus mutans. The secondary caries itself can be prevented to happen by improving the tooth flour contents. In the recent development of dentistry agent study, glass ionomeric cement is the best option as an anti-caries agent due to its natural characteristic in continuously releasing the flour ion and in being so adhesive physicochemically on enamel and dentine, that it can improve the enamel ability towards the demineralization process as well as prevent the growth of microorganisms in the oral cavity. The glass ionomeric cement itself is very sensitive to water or oral fluids, particularly when cement hasn’t become completely hard. In that condition, an easily-to-be-cracked or a fragile restoration may be created because the cement matrix formation is hampered. The best solution to prevent the glass ionomeric cement from being contaminated by water during the cement hardening process is to put coating materials, i.e. varnish. The varnish content itself which consists of natural or synthetic resin in an easily evaporating organic solvent is proved effective in creating mechanical characteristic and cement adhesion toward tooth tissue and in preventing the microleakage and the formation of secondary caries.