Fixed Appliances Orthodontics
Question 1. Explain the various components of fixed appliance. Discuss the advantages and limitations of fixed appliance.
Answer.
Orthodontics Fixed Appliance
Fixed appliances are those that are fitted on to the tooth surface and can only be removed by the operator.
Advantages of Fixed Appliances Orthodontics
- The orthodontist does not depend on the patient for timely wear and management of appliance.
- It is possible to bring about various types of tooth movements, e.g. bodily movement, rotation, intrusion and extrusion.
- Multiple tooth movements are possible simultaneously, so the treatment duration is considerably reduced.
- More precise tooth movement is possible.
- Complicated malocclusion can be treated.
- Offer better control over anchorage.
- Grossly misplaced teeth can be corrected.
- Fixed appliances efficiently treat the problem as compared to removable appliance.
- Closure of space following the extractions is best achieved by fixed appliances.
- Both crown and root movement along with establishing normal incisor relationship is possible by fixed appliances.
- Control over force distribution is precise to the individual tooth.
Read And Learn More: Orthodontics Question And Answers
Disadvantages/Limitations of Fixed Appliances Orthodontics
- Most important disadvantage is oral hygiene maintenance.
- More time consuming to fix and adjust thus take more chair side time.
- More conspicuous than removable.
- Required special training of operator.
- Damaged appliance cannot be removed by patient.
- Patient visit the orthodontist at regular interval.
- It is more expensive than removable.
- Greater possibility of producing adverse tooth movement.
- Rate of tooth movement depends on individual’s biological response.
- Effects of the treatment are restricted to dentoalveolar structure.
- Fixed appliances cannot correct the skeletal discrepancy.
- Esthetically, they are less pleasing.
- Frequent breakage can cause improper correction.
Components of Fixed Appliances Orthodontics
Orthodontics Fixed Appliances Active Components
- Arch wires
- Springs
- Elastics
- Separators.
Orthodontics Fixed Appliances Passive Components
- Bands
- Brackets
- Buccal tubes
- Lingual attachments
- Lock pins
- Ligature wire.
Active Components
- Arch wires
- Active components of fixed appliance.
- They can bring about all types of tooth movements.
- Various tooth movements are brought about by medium of brackets and bruccal tubes.
Orthodontics Fixed Appliances Classification of arch wire
Orthodontics Fixed Appliances Based on material use:
- Gold and gold alloys
- Stainless steel
- Nickel titanium alloys
- Beta titanium
- Cobalt chromium nickel alloys
- Optiflex arch wire.
Orthodontics Fixed Appliances Based on cross-section
- Round
- Square
- Rectangular
- Multistranded.
Orthodontics Fixed Appliances Based on modifications incorporated in arch wires
- Plain arch wires
- Arch wires with loop.
Orthodontics Fixed Appliances Ideal Requirements of Orthodontic Wires
- Spring back
- Softness
- Formability
- Resilience
- Biocompatibility
- Joinability
- Friction.
Arch wire escort the face to teeth through brackets and is used for achieving all types of tooth movements.
Spring
Use to bring about various tooth movements.
Types of orthodontic springs
Coil springs
- They are of two types i.e. open coil spring and closed coil spring.
- Both open and close coil springs are used to close the space between teeth.
- Open coil spring: They are compressed between the two teeth to open the space between them.
- Closed coil spring: They are stretched between the teeth to close the space.
- Uprighting spring: They are used for root movement in mesial or distal direction.
- Rotation spring: They correct the rotated teeth
- Torquing spring: They move the root in lingual or palatal direction.
Elastic
- Active part of fixed orthodontic appliance.
- Resembles a rubber band.
- Made up of latex rubber.
- Made in various diameter.
- They are color coded.
- Force applied by elastic depend on diameter.
Types
Class 1 elastic: used in intra-arch.
Generally used to close the space and retraction of teeth.
Class 2 elastic: They are intermaxillary.
- Used between lower molar and upper anterior teeth.
- Used to treat class 2 malocclusion.
Causes retroclination of anterior teeth and mesial movement of lower molars.
Class 3 elastic: They are intermaxillary elastics stretched between upper molar and lower anterior.
- Used to treat class 3 malocclusion
- Retraction of lower anterior teeth.
Crossbite elastics: It is used to treat molar crossbite box elastics: used to correct anterior open bite.
Elastic used between upper and lower anteriors
Various forms:
- Elastic chains (E-chain)
- Elastic thread
- Elastic modules
- Ligating rings.
Separators
- They are the active components of the fixed appliances and bring the separation of teeth as well as create the space between two adjacent teeth for the purpose of banding.
- Indicated in tight interdental contact to break the contact.
Principle of separator
- It wedges the teeth in a place between adjacent teeth.
- It leads to the tooth movement and separation of teeth for easy placement of bands.
Types of separators
Classification based on the material used
- Metal separators
- 0.020” brass wire
- Kesling’s separating spring
- Elastic separator
- Elastic thread
- Maxian elastic separator
- Elastomeric rings or doughnut
Classification based on duration of action
- Slow separators
- Brass wire separator: This is a soft brass wire of 0.5 to 0.6 mm diameter which is rotated via the embrasure between the teeth and should be cut short as well as tucked between the teeth and left for 5 to 7 days.
- Kesling’s spring separator: It exerts a scissor like action when kept for a week.
- Rapid separators
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- Ring separators or Doughnut or elastic ring: They are small elastic rings which pass via the contact using special plier/applicator. As it is stretched, the elastic ring encircle interdental contact area contracts and teeth are separated.
- Elastic separators or dumbbell separators: This is stretched and is passed via interdental contact area and brings the separation of teeth by regaining its original length. This is effctive after 2 to 3 days of placement.
Question 2. Write short note on parts of fied appliances.
Or
Write short note on components of fied appliances.
Or
Write short note on components of fied orthodontic appliances.
Or
Write short note on various active and passive components of fixed orthodontic appliances.
Answer.
Passive Components
Bands
These are the thin strips of stainless steel which are adapted to the contour of tooth to which other orthodontic attachments are welded or soldered. Examples are:
- Buccal tubes: They hold the arch wires and inner bow of facebow attachment.
- Lingual sheath: They receive and attach the lingual arch wire.
- Molar hooks, lingual buttons and cleats: They engage elastic bands and modules.
Bands are mainly used for the posterior teeth.
Classification of Bands
- Based on Tooth Used
![Orthodontics Fixed Appliances Based on Tooth Used](https://bdsnotes.com/wp-content/uploads/2023/05/Orthodontics-Fixed-Appliances-Based-on-Tooth-Used.png)
- Based on Fabrication
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- Preformed: They are readymade in assorted sizes
- Custom made: They are made specially as per the requirement of patient. They are contoured by orthodontists using special pliers.
Brackets
- Force needed for the orthodontic tooth movement is transmitted from active components via brackets.
- Brackets have one or more slots which accept the wire.
Classification of Orthodontic Brackets
- Based on the technique
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- Edgewise brackets
- Begg brackets
- Preadjusted edgewise
- Lingual orthodontic brackets.
- Based on the type of material
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- Metallic brackets
- Plastic brackets
- Ceramic bracket.
- Based on method of fixing
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- Bondable
- Weldable.
Buccal Tube
- Passive part of fixed orthodontic appliance.
- Fixed on buccal surface of molars.
- Also known as “molar tube”.
- Weldable or bondable.
- May have double or triple tube.
Lingual Attachments
- Fixed on lingual aspect of teeth.
- Used for engaging elastics, e.g. lingual buttons, lingual deals eyelets, ball end hook.
Lock Pins
- Used to secure arch wire to brackets with vertical slot such as ribbon arch brackets.
- Usually made of brass.
- Various types of lock pins are stage I, stage II, stage III and T pins.
Ligature Wire
- Used to secure the arch wire to the brackets.
- Made of soft stainless steel.
- Usually require for edgewise types of brackets.
Modules
- Modules are used to fix arch wire to bracket slot.
- Modules are the elastomeric rings which are used in the preadjusted edgewise technique.
Question 3. Write short note on orthodontic brackets.
Answer. These are passive parts of fixed orthodontic appliance.
- They act as handles so transmit the force from the active components to teeth.
- Brackets have one or more slots that accepts the wires.
Classification of Brackets
Based According to Slot Type
- Ribbon arch Brackets
- Brackets have vertical slot facing occlusal or gingival direction.
- Used with round wire
- Used in Begg fied appliance.
- They bring tipping of teeth in labiolingual or mesiodistal direction.
- Edgewise type of Brackets
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- They have horizontal or rectangular slot
- Used in straight wire and edgewise technique
- They provide more control over tooth movement and permit tipping of teeth.
According to Mode of Attachment to Tooth
- Weldable Brackets
- Brackets those are welded or soldered over bands.
- These brackets have a metal flange that can be welded to the band.
- Bondable Brackets
- Brackets that are bonded directly over the enamel.
- The under surface of bondable brackets has a meshwork or groove.
Based on Material
- Metallic brackets:
- Most commonly used
- Made by steel
- Can be recycled, sterilized, not expensive.
- They resist deformation and fracture.
- Esthetically unpleasing and may corrode.
- Ceramic brackets:
- Made by aluminium oxide or zirconium oxide.
- Dimensionally stable.
- Durable, resist, staining in oral environment.
- Disadvantage: They are very brittle, fracture or crack under undue forces.
- Plastic brackets:
- Made by polycarbonate
- Esthetic-tooth color or transparent.
- Disadvantage: Tend to discolor.
- Poor dimensional stability: Friction between plastic brackets and metal arch wire is very high.
Question 4. Write short note on edgewise appliance.
Answer. The edgewise appliance was introduced to orthodontics in 1925 by Dr Edward H Angle.
- He deviced a metal bracket having a rectangular slot of 0.022” × 0.028” dimension facing labially.
- Slot received a rectangular arch wire of 0.022” × 0.028” dimension.
- Wire is inserted into the bracket with the narrow dimension placed occluso-gingivally.
- Mode of insertion of the wire is called edgewise and therefore, the technique was called edgewise technique.
- Unique feature of having a rectangular arch wire in a rectangular slot enabled control of tooth movement in all the three planes of space.
- Angle described the use of an ideal arch wire that incorporated certain bends called the fist, second and third order bends.
- First order bends: First order bends are those that are made in the horizontal plane, i.e. in and out bends or labiolingual corrections.
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- These are placed to compensate for differences in the buccolingual prominence of the teeth.
- Second order bends: These bends are placed to achieve correct mesiodistal axial inclination of teeth.
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- These bends are made in the vertical plane.
- They are used for anchorage preparation or uprighting teeth.
- They are also used for the paralleling of roots and elevation or depression of certain teeth.
- Third order bends: These are torsion bends. They are placed to get correct buccolingual position by moving the roots.
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Edgewise Appliance Advantages
- Ability to move teeth in all the three planes of space.
- Good control over tooth movement.
- Bodily tooth movement is possible.
- Precise finishing is possible.
Edgewise Appliance Disadvantages
- Need to apply heavy forces.
- Need for complex wire bending.
- Increased friction between the arch wire and the bracket.
- Need for extraoral forces for anchorage.
- Difficulty to open deep bites.
Question 5. Briefly differentiate between Begg’s and edgewise mechanotherapy.
Answer.
![Orthodontics Fixed Appliances Begg's Mechanotherapy](https://bdsnotes.com/wp-content/uploads/2023/05/Orthodontics-Fixed-Appliances-Beggs-Mechanotherapy.png)
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