Angle Pearls Special Section RETENTION Interim Retainers Editor's Note: This is our third "Angle Pearls" column, edited by Dr. Gerald Nelson. We have three components of the Edward H. Angle Society of Orthodontists in the PCSO. All Angle members from the PCSO are welcome to submit their pearls to him for future issues. Conventional interim retainer Modified interim retainer When used in the mixed dentition, the retainer on the left has drawbacks: The retainer on the right is the one that serves best the purpose of an interim retainer. It holds the arch length from molar to incisor and leaves the buccal segments completely free to transition without doctor monitoring. Dr. Gerald Nelson UCSF Orthodontic Division The plastic is not trimmed away from emerging teeth, so when the permanent premolars erupt, they could be forced buccally into crossbite. The deciduous second molars are clasped instead of the permanent first molars. This prevents you from continuing the retainer through the transition and loss of the deciduous second molars. Summer 2018 PCSO Bulletin Below is an example of a lab request. Mark the plastic border away from the buccal segments and indicate a bite plane if appropriate. 49