Fixed appliances Flashcards
What is a fixed appliance?
- An appliance which is fixed to the teeth and cannot be removed by the patient that is able to produce precision tooth movements
4 advantages of fixed appliances over removable appliances?
- 3d control of tooth
- Complex tooth movements
- Control of root
- Less dependant on compliance
3 disadvantages of fixed appliances?
- Risk of iatrogenic damage
- Requires excellent oral hygiene
- Poor intrinsic anchorage
What type of movements can be produced by a removable appliance?
- Simple tooth movements - tipping
What are 2 advantages of removable appliance over fixed appliance?
- Good intrinsic anchorage
- Less iatrogenic damage
3 disadvantages of removeable appliances compared to fixed appliances?
- Greater compliance required
- Can be lost
- No control over root movement
5 indications of fixed appliance?
- tooth alignement
- correction of rotations
- Centreline corrections
- Overbite and overjet reduction
- Closing and creating spaces
What are andrews six keys (treatment goals)
- Tight approximal contacts with no rotations
- Class I incisors
- Class I molars
- Flat occlusal plane or slight curve of spee
- Long axis of the teeth have a slight mesial inclincation except lower incisors
- The crowns of the canines back to the have a lingual inclination
Other than brackets , bands , and archwire
List 4 other components of a fixed appliance?
- Modules
- Auxiliaries
- Anchorage components
- Force generating components
What is this?
Bracket
What is this?
Archwire
What is this ?
Elastic module
What is this?
Molar tube
What is this?
Molar band
3 components of a bracket?
- Bracket slot
- Bracket base
- Tie wings
What 3 materials can be used in brackets?
- Metal - SS, CoCr, Ti, Au
- Polymers
- Ceramics
What is required before placing a band?
Require space , can be achieved by placing separators
What are bands made of?
Stainless steel
What is included in the bracket prescription?
- Tip
- Torque
- In and out control
What type of retention is between brackets and tooth with composite and acid etch?
- Micomechanical retention
What would you use to bond molar bands?
GI
5 materials that can be used in archwire?
- SS
- NiTi
- CoCr
- Beta titanium
- Composite or glass
3 featured of nickel titanium archwire?
- Flexible
- Good shape memory
- Exerts light continuous force
What is meant by shape memory?
- can return to original shape
- Cannot be bent
in relation to friction, compare NiTi to SS archwire?
NiTi has higher friction than SS
2 feature of SS archwire?
- low friction - slide teeth
- Formable as can bend and create loops
4 force generating components that have sliding mechanics?
- Elastic power chain
- NiTi coils
- Intra-oral elastics
- Active ligature
Explain how teeth can move by elastics or springs?
Teeth move by utilising the energy stored in the elastic or spring
What is this?
Elastomeric chain
What is this?
Nickel titanium coil springs
What are these?
Intra-oral elastics
What is anchorage?
- Resistance to unwanted tooth movement can be explained by newton 3rd law which states that every force has an equal but opposite reactionary force
What is the first aspect of treatment planning in fixed ortho?
Anchorage
What is this type of anchorage?
- Simple- using 2 teeth (one big and one small)
What is this type of anchorage?
Compound - using two teeth to move a smaller tooth
What is this type of anchorage?
Reciprocal - using two teeth of equal size
What is this type of anchorage?
Absolute
What is absolute anchorage?
Using temporary anchorage devices which are non osseointegrating mini screws
What is this?
- Cortical anchorage
What are the advantages of cortical anchorage?
- Cortical plates provide increased resistance to tooth movement and maintains intermolar width
One example of cortical anchorage?
Nance palatal arch utilises the palatal vault for anchorage
What type of anchorage is this?
Intermaxillary anchorage using intraoral elastics
6 dental features that have a high relapse potential?
- Diastemas
- Rotations
- Palatally ectopic canines
- Proclination of lower incisors
- Anterior open bite
- Instanding upper lateral incisors
What is this type of retainer? what does it consist of and what does it do? What is the disadvantage of it ?
- Hawley removable retainer
- Labial bow to control incisors and canines
- Not well tolerated in the lower arch
A patient ask when they should wear their pressure formed retainers , what would you say?
All the time except for eating or drinking then only at night
What type of brackets cause the highest risk of enamel wear?
Ceramic
How long does average fixed appliance takes?
18-24 months
How long does hypodontia cases take ?
24-30 months
How long does orthognathic cases take?
24 -30 months
When would you make adjustments to fixed appliances?
every 4-8 weeks
What are the initial problems encountered with fixed appliances? (4)
- Pain
- Mucosal irritation
- Ulceration
- Appliance breakage
