Changes in the molar relationship between the deciduous and permanent dentitions: A longitudinal study

Resident: Roberts
Date: 10/9/09
Article title: Changes in the molar relationship between the deciduous and permanent dentitions: A longitudinal study
Author: Bishara, Samir, et al.
Journal: American Journal of Orthodontics and Dentofacial Orthopedics
Year: January 1998
Findings:
According to previous authors cited in this article, upto 50% of deciduous 2nd molars erupt to form a terminal plane relationship. Of the 50% of deciduous molars in flush terminal plane, 70% were cited in others places to develop into a class 1 relationship and 30% maintained an end to end relationship or developed into a class 2 relationship.
It has been suggested that for an initial cusp to cusp relationship to develop into a class 1 relationship, one of the two mechanisms has to occur.
1. Greater anterior growth of the mandible relative to the maxilla has to occur. (Measured by the Wits analysis; the difference in growth between point A and B on a cephalogram)
2. Greater leeway space in the mandible compared to that of the maxilla must be present.
This study was done to determine if indeed these two mechanisms or other dentofacial variables such as intercanine width and or arch length could propose a stronger relationship between that of the deciduous dentition and that of the permanent dentition.

Results within the population studied:
1). 61.6% of pts achieve ideal class 1 molar relationship, 34.3%- class 2, 4.1% - class 3.
2). Distal step – Class 2, mesial step – class 1, flush terminal plane 56% - class 1 and 44% class 2
3). A weak correlation was found between change in molar relationship and Wits analysis, and no correlation was found between the difference in leeway space between the maxilla and mandibular relationship.
4). This study concludes that only by looking at a number of dentofacial variables such as intercanine width, arch lengths, maxillary and mandibular relationships can molar classification be truly predicted.

Assesment: Not a bad article, oh yeah!