Fixed Therapy
General
The Edgewise Technique
Plan
GENERALITIES
Historical
1/ Introduction to fixed therapies
2/ The different components of fixed orthodontic devices
2-1 The brackets
2-2 Molar rings
2-3 The arches
3/ Bracket bonding technique
THE EDGEWISE TECHNIQUE
Introduction
1/ Positioning the brackets
2/ Basic principles of the Edgewise technique
2-1 Controlled dental movements
2-2 Tooth movement in the mesio-distal and vestibulo-lingual direction
2-3 Aggression movements
3/ The stages of processing using Edgewise technique
3-1 Leveling
3-2 Anchoring preparation
3-3 Closing spaces
3-4 Finishes
3-5 Contention
Conclusion
FIXED THERAPY
Historical
Since ancient times, human beings have sought ways to achieve teeth straightening in order to have a pleasant and harmonious smile.
In 1728, the Frenchman Pierre Fauchard recommended filing teeth in cases of dental crowding and described the use of a metal plate with ligatures to straighten teeth.
Edward Angle was the great precursor of modern orthodontics since he developed the Edgewise technique in 1928.
The evolution of fixed orthodontics has allowed the transition from multi-brackets to multi-attachments.
Most of these techniques are derived from classic Edgewise, this first course is devoted to generalities and the standard Edgewise technique
1/ Introduction to fixed therapies:
Since the appearance of the Edgewise technique, our discipline has experienced noticeable and prodigious progress, thanks to the contribution of cutting-edge technologies; new therapeutic methods have emerged,
This allowed the orthodontist to optimize his therapeutic protocol and offer more comfort and aesthetics to the patient.
2/ The different components of fixed orthodontic devices
2-1/ The brackets:
These are means of fixing to teeth, there are different types of brackets:
- The so-called classic metal brackets.
- Aesthetic brackets called transparent in ceramic, composite or fiberglass.
The brackets can be self-ligating or simple requiring the placement of metal or elastomeric ligatures to fix the arch.
Fixed Therapy
2-2/ Molar rings
These are means of attachment to molars.
They are sold prefabricated and are fitted in the mouth then sealed with a glass ionomer cement having carioprotective properties by releasing fluoride.
Radiopaque separators can be placed 24 hours before to facilitate the placement of molar bands.
Depending on the clinical situation, the practitioner can use molar tubes that are easier to put in place at the molar level.
2-3/ The arches
These are means of action, these arches can be round, square or rectangular in stainless steel, NITI or other materials.
The bows are changed at regular intervals and are generally of gradually increasing caliber.
Fixed Therapy
3/ Bracket bonding techniques
- Cleaning surfaces (brushes and pumice) to remove biofilm
- Installing a spacer
- Etching 15s (ortho phosphoric acid)
- Rinse thoroughly with water
- Drying
- Applying the adhesive to the enamel surface
- Application of adhesive + composite on the mesh intrados of the BK
- Centering the bracket and adjusting the positioning using a gauge
- Removing excess glue around the bracket using a probe
- Polymerization of the glue with a halogen lamp, currently practitioners use more ergonomic LED lamps which save time in the chair.
This technique described is the most classic concerning direct bonding
Another type of bonding, indirect bonding requires the use of transfer trays, this method will be detailed in lingual technique.
It should be noted that currently with the advent of new materials the steps can be reduced, and the quality of the bonding improved in particular by the use of self-etching adhesives which make it possible to combine the steps of etching and the installation of the adhesive.
The quality of the bonded assembly can also be improved by the use of hydrophilic adhesives which are not altered by saliva contamination during this bonding step.
THE EDGEWISE TECHNIQUE
Introduction
- The introduction of the rectangular arch represents the peak of the creative effort of the great American orthodontist Edward Angle.
- This technique is the treatment of choice in many difficult cases, especially cases of treatment with extraction in mixed and permanent dentition.
- The term Edgewise is explained by the fact that the rectangular arch is inserted into the bracket lumen by its narrowest side: Edge: the narrowest side, wise being the wire.
- The Edgewise bracket throat is . 022 x . 028 inches.
- In Edgewise even the second molar is banded.
1/ Positioning and gluing the brackets:
The distance between the bracket light and the free edge of the teeth is defined for each dental unit, this distance is measured using a rectangular or star gauge, the values being as follows:
Central incisor | Lateral incisor | Canines | PM | |
Upper arcade | 4 mm | 3.5 mm | 4.5 mm | At the same level as the molar tubes |
Lower Arcade | 3.5 mm | 3.5 mm | 4 mm | At the same level as the molar tubes |
2 / Basic principle of the Edgewise technique:
2-1 Controlled dental movements:
The Edgewise technique allows control in all 3 directions of the space of the dental movements carried out and this with a constant concern to respect the physiological imperatives of occlusion. These dental movements are carried out by means of arches and auxiliary forces (extra-oral forces or inter-maxillary tractions).
2-2 Tooth movement in the mesio-distal and vestibulo-lingual direction:
Tooth movement in both mesiodistal and vestibulolingual directions in the Edgwise technique is achieved by plications or bends at the level of the first order, second order and third order arch.
2-3 Aggression movements:
These movements allow the teeth to be moved in translation, in particular to move the teeth in the lateral sectors, for canine recoil for example in the case of extractions.
3 / The stages of treatment
3-1 Leveling
- Using round section arches 0.16, 0.18, 0.20, 0.22 to allow the flattening of the arches or leveling of the arches, as well as the correction of individual dystopias, we will thus obtain at this stage a progress of the dental crowding.
- These preliminary round wire arches are called leveling arches because their purpose is to bring all the brackets into uniform alignment.
- In this way the teeth are prepared for the application of the rectangular arch at a later stage.
These arches include first -order deformations made in the horizontal plane (these deformations take into account the relative thicknesses of the crowns).
We distinguish: 1st order deformations :
- In set lateral = inward offset
- Canine off set = vestibular detachment corresponding to the canine base.
- Toe in = bayonet recess in front of the first molar.
Fixed Therapy
- Beginning of retraction of canines in case of extraction
3-2 Anchoring preparation
- Anchorage preparation: this is the fundamental element of CL II treatment, its aim is to place all the teeth of the arch in a position such that they can then resist the CL II intermaxillary traction (IMT) without tilting mesially.
- The teeth should be placed in a stable position without tilting
- Anchoring can be achieved by intraoral means such as the palatal arch, the Nance arch, the lingual arch or by extraoral means such as FEB: extraoral forces
- Overbite reduction
3-3 Closing spaces:
- Closure of residual spaces with an elastomeric chain and creation of the curve of spee in the maxilla
- Mandible anchoring preparation
- Mass tooth movement (reduction of dysmorphoses)
- Use of class II or class III mechanics depending on the case
- Sectoral retraction of molars in the case of significant class II
3-4 Finishes:
- Artistic and aesthetic finish thanks to the ideal arcs carrying 1st , 2nd (Tip back and tip forward) and 3rd order (Torque) curvatures
- Coordination of the arcades
Fixed Therapy
3-5 The restraint
Carried out after fixed orthodontic therapy , retention is a mechanical system whose objective is to fix, maintain and stabilize the dento-dental relationships over time to limit relapses and secondary migrations.
Retention in orthodontics is the treatment phase which immediately follows active treatment, therefore multi-bracket treatment.
This step uses a set of processes and devices designed to prevent relapse because the teeth have a natural predisposition to returning to their initial position before treatment;
This shows the importance of containment.
Depending on the objectives and the clinical situation, different types of contention can be considered.
The most used devices are:
- A Hawley plaque
- A tooth positioner
- A retention bonded to the composite on the palatal surfaces of the teeth
Conclusion
The Edgewise technique represents the first generation mother technique and was the first technique to introduce fixed therapy to practitioners.
Since then, this technique has continued to evolve to facilitate the practitioner’s task and improve the patient’s comfort, leading to second generation techniques such as the Ricketts technique and straight arc techniques which will be the subject of a future course.
Bibliographic references:
- Boileau MJ. orthodontics of children and young adults volume 1 (Elsevier Masson Paris)2011,233
- Garcia R anchoring and therapeutics Edgewise review of French orthodontics vol 19 n 2 1985 -32-34
- Meyer M: theory of preadjusted Edgewise appliance AJO volume 73 num 5 1979 52-53
- Viennot S. retention in adults review of French orthodontics 2011;82-145 EDP science
Wisdom teeth can be painful if they are misplaced.
Composite fillings are aesthetic and durable.
Bleeding gums can be a sign of gingivitis.
Orthodontic treatments correct misaligned teeth.
Dental implants provide a permanent solution for missing teeth.
Scaling removes tartar and prevents gum disease.
Good dental hygiene starts with brushing twice a day.