The aim was to evaluate the theoretical long-term treatment costs of direct class II molar restorations (amalgam, composite, glass ionomer) using the Median Survival Times (MSTs) derived from longevity studies conducted in the Nordic countries as time for replacement. Theoretical long-term cost calculations were based on fee schedules from all Public Dental Services (PDS) in Sweden, for patients, Social Insurance Offices (SI), and total cost. Costs over 10 years were calculated and sensitivity calculations were conducted in order to demonstrate the effect of different MSTs on the long-term cost development. Glass ionomer molar class II restorations had the lowest and composite restorations had the highest initial total cost. The highest total cost over 10 years was seen for composite restorations. Amalgam restorations had the lowest long-term total cost, except when the costs were based on the shortest MSTs for each material. As there were considerable differences in the long-term costs for class II molar restorations with different materials, the importance of cost-analyses over time cannot be enough emphasised when decisions about resource allocation in the dental health insurance system are considered.