They were classified into two group, control and experimental group. Control group brushed with nylon toothbrush and experimental group did with silicone toothbrush under the researcher's guidances.

Volunteers were examined on Plaque Index(PI), Gingival Index(GI), Probing Depth(PD), Bleeding on Probing(BP) and Recession(R) at base line, 1st. week, 2nd. week and 4th. week.

According to the results, both group have the tendency of improvement in the degrees of GI, PI and the improvement degree of GI of both group has the significant differences from base line statistically, and there are not statistically significant differences between the silicone and nylon group in respect of PI, GI values.

So based on the present study, it could be carefully ascertained that the silicone toothbrush has similar effect with nylon toothbrush in respect of PI and GI.

If it is sure that the silicone toothbrush is seldom abrasive and possibly enough to massage the gingiva, this new brush is worth to be recommended by the dentists.