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1st to use extraoral force to correct protruding teeth (head gear)
Norman Kingsley
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father of orthodontics
classified malocclusion
Edward Angle (1855-1930)
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Angle normal occlusion def:
best balance, harmony, proportions of mouth in relation to other features require full complement of teeth that occupy normal position
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Edgewise appliance (1941)
- Charles Tweed
- modifying via techniques
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developed cephalometric radiograph
- Broadbent
- (post WWII)
- skeletal problems
- functional jaw orthopedics
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modern ortho
- emphasis on dental/facial esthetics (including soft tissues)
- more pt involement in tx planning
- more adults (multidisciplinary care)
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modern ortho goal
create best balance or occlusion, esthetics, stability, long term maintenence and restoration of dentition
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AAO definition
supervision, guidance, and correction of the growing and mature dentofacial structures, including those conditions that require movement of teeth or correction of malrelationships and malformations of related structures by the adjustment of relationships between and among teeth and facial bones by the application of forces and/or the stimulation and redirection of the functional forces within the craniofacial complex
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Angle vs Soft Tissue Paradigm
- ANGLE
- Primary goal: ideal occlusion
- secondary goal: ideal jaw rltn
- Hard/soft tissue rltn: ideal hard tissue -> ideal soft tissue
- Diagnostic: dental casts, ceplometric
- Tx approach: obtain ideal dental and skeletal rltn, assume soft tissues OK
- Function emphasis: TMJ relation to occlusion
- Stability: related to occlusion
- SOFT TISSUE
- Primary goal: normal soft tissue proportions and adaptations
- secondary goal: functional occlusion
- Hard/soft tissue rltn: ideal soft tissue -> ideal hard tissue
- Diagnostic: clinical examination of intra-oral and facial soft tissues
- Tx approach: Plan ideal soft tissue rltionships then place teeth and jaws as needed
- Function emphasis: soft tissue movement in relation to display of teeth
- Stability: related to soft tissue pressure/equilibrium
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Why
do non-orthodontists need to understand orthodontics?
To track the developing dentition and occlusion to provide interceptive therapy
To address esthetic and functional desires of the fully dentate patient
- To provide the highest quality comprehensive care to the partially edentulous
- patient
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What cells responsible for initial crowding to diastema in palatal expansion?
- elastic supracrestal fibers
- connect teeth together, stretch and will close diastema
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can you use removable to close diastema?
no, only point contacts, only tipping no translation
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what movement can be exclusively done with fixed appliances?
translation
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tensile forces stimulate ___ on bone surface
apposition
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compressive forces ___ on bone surfaces
inhibit apposition
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changes in function stimulate ___
remodeling of affected skeletal components
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servosystem theory
- cranial base and nasal septum not susceptible to modification (nasal septum theory
- periosteal & condylar cartilage may be (remodeling)
- sutural surfaces are susceptible (sutural)
- change in function promotes condylar remodeling (functional matrix-> soft tissue GC)
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growth modification
- increase traverse maxilla
- encourage/discourage AP growth of mand or max
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max growth modification, protraction
- force: heavy (500-1000 g much more than teeth)
- duration 12 hrs, 12-18 months
- protraction: 1000 g force, 12-24 hrs 9-12 months
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mandibular restraint
heavy force needed 24 hurs a day 6 years+
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mandibular aumentation based on what growth philosphy
- functional matrix (form follows function)
- holding in protrusion or opening stimulates condylar growth
- via pressures from muscles and soft tissues
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bionator
- mandibular growth modification
- not used much anymore
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twin block
2 removable to position mandible for growth modification
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MARA
mandibular anterior re-positioning appliance
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functional appliances force summary for mandibular growth
heavy, 24 hrs 12-18 months
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3 dimentions of bracket movement
rotation(ligation), torque(edgewise insertion square wire), tip/angulation
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1st order movement
- in-out bends: buccal lingual position, rotational
- variation in bracket base thickness
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2nd order movement
- MD tip: slot angulation
- crown root angulation: long axis angulation
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3rd order movement
- buccal lingual torque, slots of brackets different angles
- crown-root angulation
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pre-adjusted brackets "straight wire" movements
torque, angulation, in-out(thickness), off-sets (rotation)
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bracket placement relationship occlusal gingival
- arch-wire to incisal edge
- shorter is intrusion
- longer is extrusion (typically canine)
- too high: intrusion and lingual root movement
- too low: extrusion and buccal root movement
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angular bracket position
line scribe line with long axis of tooth
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archwire materials
- stainless steel: stiff, remembers form used later), correcting molar relationship and space closure (rectangular stainless steel)
- beta titanium
- nitinol (thermally active cold shaped): more flexible doesn't have shape memory, leveling and aligning
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what wire material is used to correct molar relationship and space closure?
- rectangualr stainless steel
- translation
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what wire material is used for leveling and aligning
- NiTi
- tip, rotate, extrusion, intrusion
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what wire material is used for detailing and finishing?
- stainless steel
- root uprighting, rotation extrusion, intrusion
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PDL reorg period
3-4 months post appliance removal
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gingival reorg
- collagenous: 4-6 months
- elastic supracrestal fibers: 1 year
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why are retainers used
mesial drift, entropy, gravity and poor growth persistence
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hawley retainer
- standard retainer
- acrylic, bow, clasp
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howley rentention
adams clasp, c clasp
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retainer recommendations
- 24 hrs 8-12 months
- taper off
- one night a week
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removable appliances with spring for what movement?
tipping 3-4 mm
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active retainer indications
- minor crowding or relaps
- simple crown tipping, no root angulation
- simple rotations
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spring retainers
send models to lab, lab cutos teeth out and places in ideal position and builds spring retainer to fit that position
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crozat appliance
- retenetive clasps
- body wire, lingual extensions
- minor tooth movement, arch development or molar rotation
- not used much anymore
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trutain
- clear aligner material (suck down stent)
- rigid to resist deformation
- flexible to provide ortho force
- multi-point contact
- need accurate PVS impression
- cannot be used for skeletal issues
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Light Pressue PDL
- FRONTAL RESPORTPITON
- sec: compress pressure, dilate tension
- min: dec blood flow, cytokines
- hours: metabolic, cellualr changes
- 4 hours: PDL differenctation cAMP
- days: remodel bony socket (frontal)
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Heavy PDL pressure
- sec: vessel occlude
- min: no blood
- hours: cell death
- days: differention in marrow undermining
- 7-14 UNDERMINING RESORPTION removes lamina dura by compressed PDL
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tooth movements
- translate
- root upright
- tip
- rotation
- extrusion
- intrusion
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