To observe the clinical efficacy in patients treated with two different eruption blocking appliances.

Totally 40 children (21 boys, 19 girls), aged 6.5-8.5 years old, having premature eruption of permanent tooth were randomly divided into 2 groups, with 20 cases in each group: group A (wearing traditional band and loop appliance of eruption blocking during the whole day) and group B (wearing modified band and loop appliance of eruption blocking during the whole day). The patients had regular check every 3 months until the root of premature premolar developed 1/2. The efficacy of the two appliances was evaluated on the following aspects: space maintenance, losing ratio of bands, tooth mobility and prevalence of dental caries of the premolars.

The efficacy on space maintaining and eruption impaction were not statistically different (P＞0.05), but prevalence of dental caries of the teeth in group A was higher than that of group B (P＜0.05).

The modified band and loop appliance of eruption blocking is effective and good for tooth health.