الفهرس 
Overview and historical backgroundOnly 14 pages are availabe for public view
 |  | from | 88 |  |  |
| | | from | 88 | | |
Abstract
Curve of Spee is a naturally occurring phenomenon in the human dentition. This normal occlusal curvature is required for an efficient masticatory system. The presence of a curve of Spee (COS) of variable depth is common finding in the occlusal arrangement and is sixth key of occlusion. The understanding of COS in the field of orthodontics is very important as orthodontists deal with it in virtually every patient they treat. The importance of this curve lies in its effect on space requirements during leveling of teeth. The purpose of this study was to assess the depth of the curve of Spee of mandibular arch in different malocclusion groups of Egyptian sample and to evaluate the relationship of mandibular curve of Spee to dental arch width, length and symmetry in different malocclusion groups. The sample enrolled in this study consisted of study casts of 240 patients with different classes of malocclusion within the age range of 17-25 years. All dental casts were transformed into digital format by a 3- dimensional (3D) model laser scanner (Zirkon Zahn fully automated optical structured, light Scanner S600 ARTI, ITALY) (Fig 13), Each digital image of the dental casts was transferred to a personal computer to be analyzed by an investigator (SOLIDWORKS) software. The results of this study were: • The highest measurements of curve of Spee are seen in class II division 2 subjects followed by class II division 1then class I and the smallest measurements were seen in class III subjects. • The inter-canine width highest measurements were seen in class III subjects followed by class I then class II division 1 and the smallest measurements were seen in class II division 2 subjects. • The measurements of inter-1st molar width were nearly similar in class I, class II division 1, class II division 2 and class III. • The arch length highest measurements were seen in class III subjects followed by class I then class II division 1 and the smallest measurements were seen in class II division 2 subjects.