Edgewise

Edgewise 

Plan 

1. Introduction.
2. Historical.
3. Material used.
4. Aims and principles of the technique.
   1.  The three specific principles of Edgewise.
      1. Controlled movement.
      2. Mastery of anchoring zones.
      3. Concept of the ideal arc.
5. Processing phases in Edgewise.
6. Conclusion.
7. Introduction:

Orthodontic mechanics obey physical laws in the same way as any mechanics, whatever the technique applied, the tooth will move according to the force it receives and the tissue reaction it generates.

The Edgewise technique is undoubtedly the one that offers the maximum control of dental movements in all three dimensions of space.

This is the most popular system today. However, it still presents some difficulties with regard to anteroposterior correction and anterior unlocking of the occlusion.

2. Historical

Edgewise is a multi-ring technique invented in 1928 by Angle and was presented at a conference in New London.

Angle was an orthodontist who dedicated his life to researching a mechanism that would allow him to treat his patients by restoring an occlusion as close as possible to the ideal occlusion. The Edgewise was the culmination of this research and the last in a series of mechanisms that were subsequently abandoned; Angle touted it as “the latest and best in orthodontic mechanisms.”

Edgewise

Edgewise

Many men would have considered this aesthetic, simple and effective device as the culmination of their research, but Dr. Angle was not one of those men and despite the success of his new device, he himself assessed its limitations.

This technique, despite its great possibilities, did not allow him to satisfy two important qualities that he required from an orthodontic appliance:

• The ability of teeth to move distally (or mesially) parallel to their axis;
• The ability to rigidly connect groups of teeth to serve as an anchor for a force intended to move other teeth or groups of teeth. It was to meet these additional objectives that the Edgewise was developed;
• When it was first introduced, this mechanism did not have a name, as the active element was a rectangular arch inserted into the bracket by the small side, it was given the name Edgewise, which means by the edge. 

3. Materials used:
   1. Fixed elements:

These are the main and accessory orthodontic attachments and their supports.

Supports: 

The rings made 

Bonded bases  : The most important innovation of recent years has been the use of metal bases bonded directly to the teeth by their internal faces, which carry a welded metal mesh, as supports for orthodontic attachments.

Advances in adhesive products have made it possible to increase the reliability of these bonds and simplify the operating method.

Main attachments:

They come in two forms: on the last ringed molars they are tubes; on all the other teeth they are locks or “brackets”:

Edgewise Bracket  : It consists of a block of metal with a transverse groove in its middle; this groove is a rectangular light slide measuring .022 x .028 intended to receive rectangular arches with a maximum dimension of .0215X.028, fitting with gentle friction.

As the Edgewise has evolved, the shape and size of the bracket have undergone many variations, but the principle of this assembly has never changed since the original bracket. The design of the bracket can vary depending on the user and their method.

Self-ligating bracket (Damon system): the Damon System bracket represents the new generation of self-ligating brackets, it offers greater clinical ease of use and greater reliability, it is a fully programmed biplot Straight Wire attachment.

Edgewise tubes  : these are tubes welded halfway up the vestibular surface of the molar bands; the rectangular lumen of these tubes has the same dimensions as those of the brackets.

Edgewise

Edgewise

Edgewise

Accessory attachments  : These are elements welded to the vestibular or lingual faces of the rings and intended to serve as application points for the auxiliary forces of the Edgewise.

The most frequently used are: 

• The round light extraoral force tube (.046); intended to receive the end of the face bows.
• The distal opening hooks welded to the vestibular surface of the last molars banded against the gingival wall of the Edgewise tube; they are used to attach the elastic rings.
• Lingual buttons or hooks (cleat lugs), located on the lingual surface of all braces except those of the incisors; they are very useful for the correction or control of rotations or inversions of articulation. 
• Eyelets can be soldered at various locations on the ring. 

2. Removable elements:

The arches are the specific active elements of the Edgewise appliance, they are made from steel wire of different sections depending on the treatment phases.

The first phases are carried out using round section wire, the most common dimensions of which are: .014 .016 .018 .020; then, as soon as the progress of the treatment allows, these arches are replaced by Edgewise arches, properly speaking, of rectangular section, the usual dimensions of which are: .017X.025, .019X.025, .021X.027, .0215X.028.

3. Auxiliary forces:

Aside from the Edgewise-specific forces generated by arcs, the Edgewise technique uses three other types of forces:

• Mono or intramaxillary forces;
• Intermaxillary forces;
• Extraoral forces.
• Intramaxillary forces: 

4. Goals and principles

The goals pursued by Angle were:

• To find a way to achieve unitary tooth movement in all three spatial directions using a single arch.
• Allow; always with a single arch to control the arch shape as well as its dimensions.
• Determine an arch shape so as to obtain as perfect stability as possible after treatment.
• The three specific principles of Edgewise

In Edgewise, the results of the arch analysis and cephalometric analysis will determine the treatment plan and the end of the treatment must be achieved in accordance with the objects through three specific principles of Edgewise:

• Three-dimensional control of dental movements;
• control of anchoring zones;
• the concept of the ideal arc.

Edgewise working arches are constructed from rectangular steel wire contoured on edge to give it approximately the shape of the arch; on these arches a certain number of plications or bends will be made so that the arch has in front of each attachment a conformation and an orientation specific to the position sought for each tooth and it is the effect of the attachment-arch assembly which will deliver the force to the tooth and cause its displacement. 

• First order curves: they are made in the horizontal plane and do not affect the flatness of the arch, they consist of accentuations of curves or bayonet folds towards the outside of the arch (offset), or towards the inside (in set); they can sometimes be exaggerated (overcorrection of rotations) but their main objective is to achieve a harmonious conformation of the arch taking into account the morphology of the dental crowns.
• 2nd order bends: these are bends made in a vertical plane, when the distal portion to the forceps is bent in the gingival direction, this bend is called a “tip back bend” and when the mesial portion to the forceps is bent in the gingival direction it is a “tip forward”. The role of 2nd order bends is to control the mesio-distal direction of the axis of the teeth. “Tip backs” are used systematically in the Edgewise technique in a phase of treatment called anchorage preparation, either in isolation on the last molars or in series on the teeth posterior to the canine, these bends affect the flatness of the arch, the introduction of an active 2nd order bend in the attachment lumen is done by a lever action. Modifications to the curve of Spee can be assimilated to 2nd order bends. There is a particular type of 2nd order bends called “artistic bends”, these are bends introduced in the finishing arches, they affect the incisal sector and are intended to give a slightly apico-divergent direction to the axes of the maxillary incisors.
• Third-order bends: these are made using two No. 442 clamps located in a plane perpendicular to the arc, the jaws of which are applied to the large surface of the arc; one of the clamps, acting as a vice, remains stationary, the other clamp performs a twisting movement. This change in the shape of the arc is called torque. Torque therefore designates a state and not a movement. It is the twisting conformation of a rectangular arc.

The torque that we are going to introduce on the arc can have two different forms: 

• Continuous torque: this is a uniform torsion affecting one or more teeth; therefore a sector of the arch limited by two points. It generally affects the incisal sector; in the lateral sectors, the axis of the pliers is always in the plane of the arch. In the anterior sector, the axis of the pliers forms an angulation with the plane of the arch. By moving the pliers along the entire anterior sector, the angulation remains the same. The anterior sector of the arch carries a continuous torque.
• Progressive torque: the torsion given to the arch in this case is not uniform. It mainly affects the premolar and molar sectors. The 442 clamp control will show that the further one moves away from the reference point towards the end of the arch, the more the angle between the axis of the clamp and the plane of the arch increases. The torque applied to an arch has the role of controlling the axis of the teeth in the vestibulolingual direction. It allows corrections to be made on the incisors indicated by the cephalometric analysis and in the lateral sectors to reestablish normal occlusal relationships between the antagonist teeth. Since torque is a change in orientation of a segment of an arch, it is necessary to define the direction of this change in orientation.

Mastery of anchoring zones

The forces used to achieve orthodontic movements of individual teeth or groups of teeth are reciprocal forces between the anchor point of the force and its point of application. The advantage of the “Edgewise” technique is that it can perform these movements by precisely controlling the movement of the anchor zones and the working zones in accordance with the treatment objectives. 

Definition of the anchor zone:

An anchorage zone can be defined as an area that resists movement under the effect of orthodontic forces. If the zone is located at the dentoalveolar level, this resistance can be variable; that is, the anchorage zone itself can undergo a desired or unwanted movement. This movement is referred to as “loss of anchorage.” To assess the degree of resistance we want

We will distinguish three types of anchoring:

• Natural anchors.
• Reinforced anchors
• The anchors prepared.

Concept of the ideal arc

The implementation of arches called “ideal arches” represents the final step in Edgewise processing. All the previous phases, with their strengths and auxiliaries, have no reason to exist other than to allow the simple introduction of ideal arches.

Curvatures of ideal arcs:

From the draft prepared on chart the curvatures of the three orders are placed on the arcs. 

First-order curves  : the purpose of these curves is to perfect the alignment of the teeth according to the ideal contour of the arch. They will take into account the morphology of the dental crowns so that after the action of this arch each tooth finds normal anatomical contact points with its collaterals. 

Mandibular arch: 

• It will not have any deformation at the level of the incisors but the anterior part of the arch will be very slightly flattened to be in line with the guide line.
• From a mark located between the lateral incisor and the canine, the arch will undergo an accentuation of its curve: the canine curvature.
• At the point of contact between the canine and the first premolar, a slight plication is made, in the shape of a bayonet, coming out outside the guide line (“offset”).
• At the point of contact between the 2nd premolar and 1st molar, a greater “offset” is created.
• Finally, at the point of contact between the 1st and 2nd molars, the mandibular arch is slightly angled towards the inside of the line. This plication is known as “toe in”.

Maxillary arch: 

• A first deformation will be made between the central incisor and the lateral incisor due to the smaller volume of the latter. This internal bayonet deformation is called “in set”.
• At the level of the lateral incisor-canine contact, the arch is brought inwards and goes around the canine with an accentuated curve.
• The following deformation is located between the 2nd premolar and the 1st molar: it is an “offset”.
• When the 2nd molars are banded, a final, slightly less marked “offset” is made between the 1st and 2nd molars.

Second-order bends: These are a function of the movements made during treatment. If a TWEED-type anchorage preparation has been made, tip-back bends will be placed on the ideal arch. Tip-back, tip-forward, and step-up bends may be necessary for overcorrection of vertical anomalies (overbites). Artistic bends are placed in the anterior sector.

3rd order curvatures:

In the mandible:

• No torque at the incisor level.
• Little or no torque at the canines 
• Progressive radiculo-vestibular torque on the lateral sectors from the premolars.

In the maxilla:

• Radiculopalatine torque in the anterior sector. 
• Variable torque on the canine depending on its morphology and the light position of the bracket .
• Progressive radiculo-vestibular torque in the lateral sectors from the premolars.

Coordination of the arcs: 

The checkpoints in the mouth after the installation of these ideal arches will be as follows:

• Concordance of environments.
• Class 1 angle relation.
• Continuity of contact points.

• Concordance between the position of the mandible in centric relation and in terminal occlusion.
• Anterior guide in propulsion with posterior distocclusion.
• Side canine guides work in lateral movements.
• Absence of interference from the non-working side in lateral movements.
• the coordination of arch shapes;
• Adjustment of 2nd and 3rd order curvatures;
• Hypercorrection of the vertical and anteroposterior directions

7. Conclusion :

In all cases where the treatment involves tooth movement, the Edgewise technique offers the most rigorous mechanical possibilities. Since its invention, it has given rise to various methods.

Edgewise

Deep cavities may require root canal treatment.
Interdental brushes effectively clean between teeth.
Misaligned teeth can cause chewing problems.
Untreated dental infections can spread to other parts of the body.
Whitening trays are used for gradual results.
Cracked teeth can be repaired with composite resins.
Proper hydration helps maintain a healthy mouth.
 

Edgewise