Curve of Spee - from orthodontic perspective

Abstract

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. An excessive COS is a common form of malocclusion that may be addressed in many ways, including posterior extrusion, anterior intrusion, and incisor proclination. The specific approach to leveling of COS should be selected based on each patient's needs. Soft tissue, crown–gingival relations, occlusal plane, and skeletofacial concerns are among the special considerations for treatment planning for leveling of COS.

Curve of spee: a literature review

“…A variation of this practice is to proceed with maxillary exaggerated COS wires or/and mandibular reverse COS. Increasing step bends in an archwire similarly levels the COS. Other methods consist of the use of a bite plate, which permits the posterior teeth to erupt. In addition, altering bracket placement heights helps to level the COS as well 30 . A main concern is that every millimetre of extrusion increases the incisor overlap by between 1.5-2.5 mm 29,30 .…”

“…The indications for extrusion of posterior teeth are short lower facial height and moderate-to-minimal incisor display 29,30 . On the other hand, the disadvantages are instability in non-growing patients, increase in the interlabial gap, excessive incisor exhibition and worsening of gingival smile 21,30,32 . Furthermore, extruding posteriors could cause a rise in lower facial height and patients with strong facial muscles have a tendency to relapse after the orthodontic treatment 33 .…”

“…The intrusion of incisors is a necessa-ry method to level COS particularly for patients with a large vertical dimension, excessive incision-stomion distance and a large interlabial gap. 29,30,34 . The four most common techniques are: Burstone 19 , Begg and Kesling 35 (1977), Ricketts 36 (1976) and Greig 37 (1983).…”

“…The four most common techniques are: Burstone 19 , Begg and Kesling 35 (1977), Ricketts 36 (1976) and Greig 37 (1983). The four methods apply tipback twists at the molars to provide an intrusive force at the incisors and recognise the extreme significance of a light and continuous force application 29,30 . On the other hand, this orthodontic treatment has a notable risk factor associated with external apical root reabsorption 38,39 .…”

Evaluation of the Depth of the Curve of Spee, Overjet, and Overbite in Class I, Class II, and Class III Malocclusion Among Patients at University of North Sumatera Dental Hospital

“…Andrews proposed that flattening the occlusal plane should be the treatment goal in orthodontics. The value of the curve of Spee depth as the sixth key to normal occlusion should be considered and quantified in space management procedures to prevent incisor flaring and consequently assuring aesthetics and the stability of both the treatment results and function [3,4].…”