Abstract
We applied MPBA modified facial masks to the skeletal reversed occlusion in the deciduous dentition and examined the effects of theappliance.
The materials consist of 22 lateral cephalograms of 11 Japanese girls, which were taken before and after the treatment and 39 lateral cephalograms of 13controls, which were observed in natural growth.
The following results were obtained:
1) Forward movements of point A, Ptm and the unerupted upper permanent incisors were statistically significant. However counter-clockwise rotation of NF and forward movement of Or and PNS were not significant.
2) Clockwise rotation of the mandible occured significantly.
3) The ratio of the movement of the four points which contributed to the improvement of the reversed occlusion was that backward movement of point B and the labial tipping of the upper deciduous incisor were about one third of the overall movements respectively and forward movement of point A and lingual movement of lower deciduous incisor were about one sixth of the overall movements respectively.
From these results, it was seen that the MPBA causes the effective changes in skeletal class III patients in deciduous dentition, namely growth acceleration on the maxilla and clockwise rotation on the mandible.
