Implants and Ortho (Bibona) Flashcards
What are some reasons why Temporary Anchorage Devices (TADs) have become popular?
- Commercial availability
- Ease of placement
- Lack of patient cooperation
- Possibility of achieving better anchorage control during mechanotherapy
What is the term for resistance to unwanted tooth movement. With respect to ortho, it is the resistance to reaction forces that is provided by other teeth, by the palate, head or neck, and by anchors screwed to the jaws?
Anchorage
Which one of Newton’s Laws does Anchorage seek to minimize?
Newton’s 3rd Law: for every action there is an equal and opposite reaction
What is an important aspect of orthodontic treatment with respect to tooth movement?
Maximize desired tooth movement while minimizing undesirable side effects
What is central to achieving ideal overjet and overbite correction?
Anchorage control
What type of anchorage are Temporary Anchorage Devices (TADs) used for ?
Stationary or absolute anchorage
The stationary / absolute anchorage of TADS is synonymous with what?
Skeletal anchorage
What is the type of anchorage where the TAD receives reactive forces of a moving tooth / teeth?
Direct anchorage
What is the type of anchorage where the TAD is connected via a bar or a wire to a stabilized tooth, which receives the reactive forces of tooth movement?
Indirect anchorage
TADs can be used to do what to posterior teeth?
Protraction of posterior teeth
TADs can be used to do what to anterior teeth?
Retraction of anterior teeth to distal
What is the stability of TADs based on: mechanical retention or osseointegration?
Mechanical retention
Do TADs osseointegration?
No
What is the max torque a TAD is placed with?
5-10 Ncm torque. Any more than that causes compression necrosis.
What are 4 things affecting TAD stability?
- Thickness of cortical bone
- Implant design
- Implant site preparation
- Insertion torque
How much cortical bone is needed for TAD stability?
1-2mm
What are 3 considerations for the location of a TAD?
- Root proximity
- Cortical bone thickness
- Gingival type
Where do they think the TAD is best placed with respect to the gingiva?
Mucogingival junction
What are 3 things to determine with respect to biomechanics considerations before placing TADs?
- Desired tooth movement
- Desired force system and its equilibrium
- Side effects on the teeth and the anchorage system
What are 5 indications for TADs (5 tooth movements)?
- Intrusion of maxillary teeth
- Distalization of molars and groups of teeth
- Canine retraction and intrusion retraction mechanics
- Anterior open bite correction
- Molar protraction and maximum anchorage
What ortho can be done if there is a supererupted maxillary molar decreasing area for mandibular restoration?
Molar intrusion
What must be considered when intruding a tooth with respect to bone levels?
Surrounding bone levels. Want it higher with the tooth to avoid causing a perio defect as the tooth intrudes and takes bone with it
How many TADs are placed to intrude a tooth?
Two (one on each side). Buccal plate attached to zygomatic buttress and one in the palate.
What would happen if only a TAD was placed on the buccal?
Would only tip the molar in that direction
With respect to resistance where should the TAD be placed for molar intrusion?
At the center of resistance
Will there be some relapse after molar intrusion?
Yes, so sometimes go a little further than needs.
If you an have anterior open bite patient with anterior crowding and want to level and align them first with ortho, where is the only way for the teeth to go?
Flare out, therefore the open bite opens a bit more.
What is another way to close an anterior open bite?
Place a transpalatal arch and a buccal TAD to intrude the maxillary molars
What is the purpose of the TPA when closing an anterior open bit with TADs by intruding the maxillary molars?
Aides the intrusion and stops the buccal tipping
How does using a TPA and a Buccal TAD close an anterior open bite?
Intrudes the molars lowering the maxillary occlusal plane, causing the mandible to rotate up, which closes some of the distance to the maxillary anteriors
How will an anterior open bite closing be finished after the maxillary molar instrusion via TPA + Buccal TAD?
Some anterior extrusion to close
What is the force system in a buccal TAD?
The force is intruding apically. The system is buccal to the center of rotation, so the tooth will roll buccally as it intrudes. That is why you place a palatal TAD or TPA.
For every ___ mm of molar intrusion you get a ___ mm of closure in the anterior open bite?
1mm intrusion 2mm closure (or 2mm increase in overbite)
What is a problem with molar protrusion (bringing molars anterior) especially if it is a unilateral molar protrusion?
Shift of the midline towards side being protracted. Opposite arch problems for the arch that is used as anchorage to protract the opposite molar.
What is the TAD for molar protraction a good choice?
It saves the midline
Protrusion of molars uses what type of anchorage: direct or indirect?
Direct, the TAD receives all the force to move the molar forward
How could indirect anchorage be used to protract a molar?
Attach a group of anterior teeth to the TAD, then use this stabilized group of anterior teeth as the anchorage that protracts the molar (the anteriors are protected from midline shift because their anchorage is the TAD)
How can asymmetric space closure be accomplished with TADs?
With simultaneous protraction and retraction.
What are 2 things that TADs provide?
- Maximum anchorage
2. Ability to do asymmetric mechanics
TADs are based on principles of what?
Biomechanics
