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Orthodontic appliance is a device that is used to produce changes in the relationships of the teeth and the skeletal structures.
TYPES OF ORTHODONTIC APPLIANCES
- REMOVABLE .
- FIXED .
They are designed to be placed & removed by the patient as directed by the orthodontist.
TYPES OF REMOVABLE APPLIANCES
1. INTRAORAL .
2. EXTRAORAL .
1. INTRAORAL APPLIANCES
Types are Either
I. Removable such as :
1. Functional appliances.
2. Active retainers.
3. Passive retainers & positioners.
II. Fixed :
Is a removable device that is frequently used during growth to correct skeletal imbalance and produce changes in the differential growth rate , before placement of fixed appliances .
Are used to achieve minor tooth movement (tipping movement) .
RETAINERS & POSITIONERS
Are removable appliances that are used to hold or retain alignment of the teeth after fixed appliance therapy.
Are constructed to maintain the spaces for the permanent teeth after deciduous teeth loss .
2. EXTRAORAL APPLIANCES
It is an appliance that is worn outside the mouth to gain force from the head & neck to change the differential growth rate.
- Is an orthopedic device that can be used in conjunction with fixed or removable appliances ,it is used to control growth & tooth movement.
- It is made of two parts :
Facebow & the traction device .
* It is used to stabilize or move the maxillary 1st molar distally to create more space in the arch.
* It has an intra & extra oral parts ,the intra will fit into the buccal tube of the maxillary 1st molar .The outer part of the bow attaches to the traction device .
It applies the extraoral force used to achieve the desired Tx results .
It has four types :
High pull ,cervical ,combination & chin cap .
HIGH PULL : It is a caplike device that fits around the pt head &hooks perpendicular to the occlusal plane. It is used to control growth of the maxilla or retraction of anterior teeth.
Cervical pull : It fits around the pt’s neck. The exerted force is parallel to the occlusal plane. It is used to stabilize or distalize the 1st maxillary molars
Combination : It is a combination of high pull & cervical traction devices It exerts a force along the occlusal plane & upward .
Chin cap : It is a combination of high-pull strap & a chin cup that fits on the mandible. It controls mandibular growth in Cl III patients .
- They are attached to the teeth which are removed by the orthodontist.
- It is called braces.
- It can move teeth in six directions:
Mesially, distally , lingually, facially, apically & occlusally ,as well as rotationally.
COMPONANTS OF FIXED APPLIANCE:
- Attachments include bands (esp on 1st & 2nd molars) & brackets bonded directly to the teeth (esp on anterior & premolar teeth) .
- Axillaries (attach arch wire to brackets & bands to move teeth such as tubes, hooks & elastics .
- Arch wires are attached to the brackets by bending the wire it will give force & pressure that cause teeth to move in the desired direction .
After decision has been made that fixed appliance should be used Tx plan will be discussed & pt will be prepared to receive separators.
SEPARATION OF TEETH
Separator is a device that force or wedge the teeth a part so bands can be fitted easily.
It involves three separating methods :
Brass wire separators ,steel separating springs, & elastomeric separators.
1. ORTHODONTIC ATTACHMENTS ARE :
– Bands are preformed stainless steal rings which has to be selected properly on diagnostic cast or by visual inspection of the size.
– They are divided into maxillary & mandibular (R & L).
CEMINTATION OF ORTHODONTIC BANDS
Cement has to have strength to aid in retention with enamel as (zinc phosphate), as well as a time-released fluoride to prevent decay under the bands as (glass ionomer) .
- The most common type is the edgewise brackets .
- It is made of stainless steal & attached to a backing pad ,it has four wings to attach the arch wire to it after placing it horizontally .
- It has auxiliary attachments such as headgear tubes ,edgewise tubes ,labial hooks ,lingual arch attachments .
PREPARATION OF TEETH
- Teeth should be polished by pumice & rubber cup to remove pellicle & food debris .
- Acid etching will be placed on the tooth surface for 15 seconds then washed & dried .
- Monomer agent will be applied on the tooth surface as well as the bracket .
- In addition to the agent the boding material will be placed on the bracket only .
- The bracket pressed on the tooth surface & the excess will be removed .
2. ARCH WIRES
- It is shaped like a horse shoe ,when it is tied to the brackets it provides sufficient force to move teeth .
- It has several types with each has different properties eg Nickel titanium ,Stainless steal wires .
- In addition it has different shapes & sizes (Round ,Square & Rectangular).
It has tow types :
1. Ligature wires are twisted around the bracket to hold the wire in place .
Kobyashi hooks has a hook for attachment of elastics .
2. elastomeric ties are made of plastic or rubberlike material & available in many colors .
3. Power products it can move teeth & the tow commonly used types are elastic chain ties (to close spaces) & elastics (rubber bands) from one tooth to another in the same arch or teeth in opposing arches to move teeth in certain direction.
ASSISTANTS RESPONSIBILITIES :
- Assistant should check the pt appliance for any
- Broken or missing arch wires
- Loose brackets & bands
- Loose or broken or missing ligatures
- Loose or broken or missing elastics .
2. Oral hygiene & dietary instruction: -Should be given to avoid food trapment & plaque accumulation because bad oral hygiene will lead to rampant caries & periodontal disease .
-Also ice ,popcorn ,nuts & sticky foods should be avoided because they will cause band loosening , bracket popping off & arch wire bending .
- When Tx finished the appliance will be removed & teeth should be cleaned and polished .
- All records will be retaken (Impression , radiographs and photographs ) .
- As well as a removable or fixed retainer will be constructed .
Is necessary to :
- Allow gingival & periodontal tissues reorganization .
- Support unstable teeth to prevent relapse .
- Control growth changes .
TYPES OF RETENTIVE APPLIANCES
1. POSITIONERS .
2. HAWELY RETAINERS .
3. LIGUAL RETAINERS .
- Is a custom appliance made of rubber or pliable acrylic that fits over the dentition after orthodontic Tx completion .
- It is designed to :
Ø Retain teeth in desired position .
Ø Allows alveolus rebuilding around the teeth before retainer is given .
Ø Massage the gingiva .
2. HAWELY RETAINER
It is constructed of clear ,self-polymerizing acrylic to hold wire clasps on molar teeth .
In maxilla it covers the palate ,while in the mandible it covers the anterior floor of the mouth .
It passively hold the teeth after fixed appliance removal ,also it allows some tooth movement to close band spaces & control incisors
3. LINGUAL RETAINER
It is a cuspid to cuspid fixed retainer which is fabricated from light stainless steal wire & bent to rest against the lingual surface of the teeth to maintain incisor position during late growth .