Short communication: Influence of preformed metal crowns (Hall technique) on the occlusal vertical dimension in the primary dentition.

AIM: This was to investigate the measure of propping, or occlusal interference and opening the bite after placement of preformed metal crowns (PMC) using the Hall technique and in how many days it took for the open bite to return to normal.

METHODS: For this study school children living in the rain forest of Suriname were selected. The distance between the tip of the mandibular and maxillary primary canines was measured just before and after treatment with PMCs and again after 15 and 30 days.

RESULTS: In 48 children the mean distance between the canine tips reduced from 2.45 mm before to 0.54 mm directly after treatment. After 15 days the distance increased again to 1.96 mm and after 30 days (with the remaining 8 patients) to 2.75 mm. The reduction of the overbite seems to be caused by intrusion of the crowned molar and its antagonist.

CONCLUSION: Although the overbite had equilibrated after 30 days, additional research is necessary in a larger study to draw more decisive conclusions.