A Study of the Relationship between the Development of Skeletal Malocclusion and the Tooth Crowding in Posterior Part of Dentition

1992 Fiscal Year Final Research Report Summary

• Project/Area Number: 03670983
• Research Category: Grant-in-Aid for General Scientific Research (C)
• Allocation Type: Single-year Grants
• Research Field: 小児・社会系歯学
• Research Institution: Kanagawa Dental College
• Principal Investigator: SATO Sadao Kanagawa Dental College, Dept. of Orthodontics, Associate Professor, 歯学部, 助教授 (00084799)
• Co-Investigator(Kenkyū-buntansha): AKIMOTO Susumu Kanagawa Dental College, Dept. of Orthodontics, Assistant Professor, 歯学部, 講師 (70147990)
• Project Period (FY): 1991 – 1992
• Keywords: Discrepancy / Skeletal Malocclusion / Over Eruption / Vertical Dimension / Monkey / Mandible / Growth

Research Abstract

In order to clarify the relationship between the development of skeletal malocclusion and the over eruption of molars due to posterior tooth -to-denture base discrepancy, a model experiment using monkeys have done in this study. Metal crowns were made and fixed on the right and left maxillary first molars of experimental animals to increase the vertical dimension of occlusion. This procedure was duplicated after one month of fixing the first crown and providing the increasing 2mm of the vertical dimension totally.
Growing animal indicated that the forward displacement of the mandible followed by the condylar growth was associated with increasing the molar height. This response of the mandible induced the anterior cross bite of occlusion. However, adult animal showed that the backward rotation of mandible was induced by the increasing vertical dimension, providing the anterior open bite occlusion. These findings are suggesting that the molar over eruption due to posterior discrepancy is one of the important etiologic factors in the development of skeletal malocclusion such as skeletal class III and skeletal open bite.