Abstract: Objective To compare the clinical effects between flowable composite resin and glass ionomer in filling interproximal early caries of primary molars. Methods Self control method was used. 45 teeth were included in each group. The conservation condition of each group in 3 months, 6 months, 12 months was observed. Results The general failure rate of glass ionomer was significantly higher than flowable composite resin in the restoration of interproximal early caries of primary molar(P＜0.05). The failure rate gradually became higher and higher over time. There was not a significantly difference until 1 year later after the restoration(P＜0.05). As for the characteristics of antifracture and abrasive resistance，flowable resin was better than glass ionomer among various failed reasons analysis(P＜0.05). Conclusion Suitable material should be selected according to different cases because every material has its two sides, although the general failure rate of ionomer is higher than the flowable resin in filling interproximal caries of primary molars.

Key words: 【Key words】flowable composite resin, glass ionomer, primary molar, interproximal early caries