Textbook for Orthodontic Therapists. Ceri Davies
way:In and out (first‐order bend): to achieve this, the base of the bracket is manufactured differently. For example, lateral incisors sit slightly back from the central incisors, therefore the base of this bracket will be thicker than the brackets for the central incisors.Tip (second‐order bend): each bracket slot is cut at a certain angulation to help achieve the correct angulation for each individual tooth; this differs for each bracket.Torque (third‐order bend): each bracket has different torque percentages within the bracket slot. The thicker the wire, the more torque is created. If the desired torque is not achieved, bends within archwires can be placed to help with this type of movement.
Preformed archwires are used with this appliance, as this allows teeth to move gradually from their original position into their desired position.
Brackets come in different slot sizes:0.018 × 0.025 in., with the working wire being used = 16 × 22 ss (stainless steel)0.022 × 0.028 in., with the working wire being used = 19 × 25 ss (more commonly used).
Depending on the degree of crowding the patient presents with, the appliance can be used on non‐extraction or extraction cases.
Still in good use today, the preadjusted edgewise appliance has three common bracket prescriptions:AndrewsRothMBT = McLaughlin, Bennett, Trevisi.
Different orthodontists created these three common bracket prescriptions. It was known that each orthodontist had different views on how much torque should be built within the bracket slot. Therefore, each bracket prescription contains different values of torque, with MBT containing the highest value of torque out of the three.
Advantages of the edgewise appliance:
Reduced chair time.
Amount of wire bending is minimised.
Sliding mechanics for tooth movement.
Good finishing.
Disadvantages:
Larger inventory of brackets is required, as each individual tooth has different requirements of in and out, tip and torque.
Ignores individual biological variation.
Increased friction has implications and increases anchorage considerations.
1.5 Tip Edge Appliance
Peter Kelsing:
Developed the tip edge appliance in 1986.
Is an American orthodontist, born in La Porte, Indiana, and is the son of Harold Kesling who was also an orthodontist.
Peter also has one son called Chris Kesling who followed in both his father’s and grandfather’s footsteps and works as an orthodontist at the same practice in Westville, Indiana.
Tip edge appliance:
Developed based on the best features of the Begg appliance (round wires, light forces) and the preadjusted edgewise appliance (detailed finishing).
There are three stages of treatment when using this appliance:Stage 1: Align teeth, correct incisor and molar relationship, crossbites and rotations.Stage 2: Start space closure and maintain stage 1 corrections.Stage 3: Correct inclination of teeth.
Each bracket incorporates the inbuilt prescriptions (in and out, tip, torque).
Round archwires are used for the initial tipping and aligning stage and the later stages have the use of the rectangular archwires, which gives more control over tooth movement and helps with the final detailing.
To ensure full engagement, the archwire is engaged into the bracket slot by the use of elastomeric modules or metal ligatures.
1.6 Self‐ligating Appliance
Self‐ligating appliance (Figure 1.6):
Developed in 1990.
Became very popular among non‐extraction orthodontists and was initially used on non‐extraction cases.
Self‐ligating brackets incorporate a door/clip which ensures full engagement, and holds the archwire in place within the bracket slot.Figure 1.6 Self‐ligating appliance.
There are two types of self‐ligating bracket:Passive: has a slide mechanism which is passive and places no active force on the archwire.Active: Places an active force on the archwire.
Once engagement of the archwire has been made by the door/clip, the archwire is free to move in brackets, making the appliance free‐sliding.
The circumference of the arch is increased, due to space being created on expansion to align teeth, leading to the wide smiles we see today.
Inter‐arch elastics are used in conjunction with self‐ligating appliances to help improve the patient’s occlusion.
Self‐ligating appliances are known to reduce chairside time as adjustments are quicker.
Different types of torque are available within the brackets, such as standard/high/low torque.
Manufacturers claim that self‐ligating appliances produce lower friction.
Examples of self‐ligating systems:
Damon® – 3, 3mx, Q, Clear (Ormco Corporation, Orange, CA, USA).
Clarity™ SL (3M, St Paul, MN, USA).
Harmony (ASO International, Tokyo, Japan).
SmartClip™ (3M).
SPEED System™ (Haspeler Orthodontics, Cambridge, ON, Canada).
In‐Ovation C® (Dentsply Sirona, Woodbridge, ON, Canada).
Advantages:
Provides low friction.
Achieves full archwire engagement.
Quick and easy to use.
No elastomeric modules, which makes oral hygiene easier to control.
Patient can go for longer intervals between appointments.
Disadvantages:
If there is a fault in the door/clip, it means the whole bracket is faulty, therefore a new bracket would be needed.
Appliance can be harder to ligate wire; it is important to make sure the wire is fully engaged in the bracket slot for the door to close.
Higher cost in brackets.
Difficulty in finishing due to the incomplete expression of the archwires.
1.7 Advantages and Disadvantages of all Types of Buccal Appliances
Advantages:
Appliances allow good working access.
Once the clinician is experienced they are easy to work on.
Chairside working time is reduced.
Can achieve excellent finishing and detailing – archwire bending is easier.
Aesthetic brackets and archwires, which are popular with patients.
Quicker treatment time as opposed to lingual appliances.
Disadvantages: