Abstract: Objective: To compare the clinical effect of Palodent and circumferential matrix systems in filling the paired posterior teeth. Methods: One hundred and two paired cavities with classⅡcavities which met with the inclusion criteria were randomly divided into study group(Palodent group) and control group( circumferential group). One doctor-in-charge completed all the cavity filling. Immediately after cavity filling,one week later and one year later,questionnaires were filled by another doctor to evaluate the comfort level,food impaction,anatomical shape,marginal ridge,proximal contact and gum inflammation. Results: There were significant differences on indexes of comfort level, food impaction, anatomical shape, marginal ridge, proximal contact, gum inflammation between the two systems. Conclusion: Palodent matrix system is better than circumferential matrix system in filling the peired posterior teeth.

Key words: The paired posterior teeth matrix system, Resin filling , Proximal contact