The Consideration of Dental Development In Serial Extraction

Resident’s Name: Brian Schmid DMD Date: 10/2/09
Article title: The Consideration of Dental Development In Serial Extraction
Author(s): Conrad Moorrees DDS, Elizabeth Fanning DDS and Anna Marie Groen
Journal: ?
Month, Year: January 1963
Major topic: All you ever wanted to know about serial extraction but were too afraid to ask
Type of Article: Literature Analysis
Findings: Variance in tooth size and arch size determine the presence of spacing and crowding; crowding can occur in patients with less than average tooth size or larger than average arch size. This can become complicated when predicting tooth and arch size in the developing dentition. The mean size difference between permanent and primary maxillary incisors is 7.4mm in males and 6.mm in females, with arch breadth increasing only ~3mm. In the mandible, the average difference in M-D widths is 5.1 ni males and females. On average, when primary tooth spacing is included there is enough room for the maxillary incisors and nearly enough in the mandible, leading to mild crowding there. During eruption of the maxillary incisors, 50% of children did have some crowding. During the second stage of dental development, the eruption of canines and premolars, the maxillary intercanine width increases 2mm in the maxilla and decreases slightly in the mandibular. The pattern of exfoliation, the location of the mandibular 2nd premolar and the depth of intercuspation of the 6 year molars dictates how much of the leeway space may be lost by mesial drift. Predicting adult intercanine width is difficult from age 9 years to adulthood and can vary from 1.2 to 1.6mm. In general, ¾ of root length is developed upon eruption of canines and premolars, canine being slightly longer when they pierce through the gingiva. Therefore, deciduous molars should not be extracted before ¼ root development if the tooth is near emergence or ½ if not. Primary canines should not be extracted before ½ root development of the permanent canines or the 1st premolar has already erupted. While we can predict leeway space well using dental casts and radiographs, predicting growth of arch size is very tricky and variable. It is best to be as conservative as possible when considering serial extraction and to monitor eruption of permanent teeth as well as root formation to optimize orthodontic diagnosis and proper treatment planning.

Assessment of article: Very good article.