How can we help?

You can also find more resources in our Help Center.

219 terms

Ortho Final Spring 2012

STUDY
PLAY
requirements for normal occlusion
No open bite
minimal overjet
minimal overbite
normal tooth size
max intercuspation w/o shift
Dr. Andrews 6 keys to normal occlusion
Molar Key
crown angulation = mesiodistal tip
crown inclination
no rotations
no spaces and all teeth in contact
occlusal plane = flat to slight spee
___ is the distal surface of the distobuccal cusp of the maxillary 1st molar should be in contact with the mesial surface of the mesiobuccal cusp of the mandibular 2nd molar
Molar Key
The 2nd key to normal occlusion is the ___ which is a ___ and when the ___ is more distal than incisal
crown angulation
mesial tip of long axis/crown
gingival portion of long axis of clincal crown
____ determines the mesio-distal space occupied
crown angulation
crown inclination for:
- upper and lower anteriors
upper posteriors
lower posteriors
- labial crown inclination
- Lingual
-Lingual (progressively inclined as move back)
T/F Roated teeth take up more space than non rotated teeth
True
Flat occlusal plane permits ____
max intercuspation
____ is the father of modern ortho, credited with much of occlusal concept
Edward H. Angle
Angles 2 postulates
Upper 1st molar = key to occlusion
MB cusp of upper molar should occlude in buccal groove of lower molar
____ is a smooth curve passing through central fossa and over cingula of max teeth and buccal cusps/incisal edges of mandibular teeth
Line of Occlusion
Normal molar relationship
line of occlusion is incorrect due to malposed/rotated teeth
Class I Malocclusion
Lower molar = distally positioned relative to upper (overbite)
Line of Occlusion NOT specified =
Class II Malocclusion
Protruding Upper Incisors
Class II Division I
Retrusive Upper Incisors
Class II Division II
Lower molar is mesially positioned relative to upper molar (UNderbite)
Line of occlusion not specified =
Class III
Class II jaw relationship
mandible distal =retronagthic
usually with class II moalr relationship
Class II growth pattern
Down and Back growth of mandible
Class III jaw relationship
Mandible mesial = pronagthic
Class III growth pattern
forward growth of mandible
Profitt and Ackerman's 5 major characteristics
1. facial proportions and aesthetics
2. alignment and symmetry w/in distal arches
Skeletal and dental relationship:
3. Transverse plane
4. anterioposterior plane
5. Verticle plane
convex facial profile=
class II jaw
Concave facial profile =
class III
_____ = anterior or posterior inclination of the lower face relative to forhead - does not indicate facial/dental disproportions
Divergence
Intra-Arch alignment and symmetry takes into account ____
crowding, spacing, symmetry
transverse deviation includes ___ where max posteriors are lingually postioned relative to mandibular teeth
posterior crossbite
___ =upper molars are lingual to normal
bilateral max lingual x-bite
____ is when lower molars are buccally postioned on 1 side
unilateral mandibular buccal x-bite
___ is due to displacement of teeth from normal positoned adequate palatal width
Dental Crossbite
_____ is due to inadequate palatal width
skeletal x-bite
Overjet =
horizontal overlap of incisors (should ideally be 2-3mm)
US population have 35% with normal occlusion and 65% w/ malocclusion - ___ with an Unknown cause
5% (so majority of malocclusion the cause is known)
Etiologic factors of malocclusion include
specific causes, genetics, environment
_____ = chemical agents producing embryo defects
Teratogens
IntraUterine molding, trauma to mandible and jaw fractures are ____
skeletal growth disturbances
____ can affect Jaw growth
muscle dysfunction
Musculature usually pulls jaw ____
down and forward
_____ caused by excessive growth hormone release by ______ pituitary tumor which results in excessive ____ growth
Acromegaly
Anterior
Mandibular
Unknown cause, unilateral excessive mandibular growth, common in females 15-20 yrs old
Hemimandibular Hypertrophy
Sclerotic bone, heavy fibrous gingiva, CC (Cleidocranial Dysplasia) and ankylosed premolar are all characteristics of
eruption interference
____ is multiple supernumerary teeth which lead to mechanical interference of normal tooth eruption
CCD = Cleidocranial Dysplasia
early loss of primary teeth leads to ___
Drifting
*** 2 ways genetics can lead to malocclusion inheritance
1. disproportion between size of teeth and size of jaw = crowding or spacing
2. disproportion between upper and lower jaws = improper occlusal relationshps
T/F primitive man had better occlusion
True - if they didn't they were natural selected out of population cause they couldn't eat correctly
____% of dental/Facial variation can be attributed to heredity factors
40%
Heritability of skeleton = __
Heritability of dentition = ____
because environment leads to ____
High
Low
dental variation
What is the strongest genetic influence
mandibular prognathism = hapsburg jaw
2 theories of environmental influence
Equilibrium = pressure from cheeks, jaw
Functional influence = form/function
____ would be a equilibrium effect on dentition
tongue pressing against and moving teeth after a stroke
____ is a functional influence on dentofacial development
thumbsucking
narrow+ steep maxillar, anterior open bite, tongue lowers and pressure on upper molars, cheek pressure contricts upper arch are results of =
thumbsucking
altered respiration (i.e. breathing through outh) can result in
adenoid facies
what are the 2 purposes of ortho records
treatment start point
additon of info from clinical exam
3 major categories of ortho records
health of teeth and structure
allignment and occlusal relations
facial and jaw proportions
standard ortho records (Steps)
interview
exam w/ photo, radio, cephalo
study casts
collection of diagnostic database
class II skeletal jaws are possible candidates for
head gear for skeletal modification
___ determines vertebral maturation and predicts remaining growth
cephalometric radiograph and hand wrist
____ around crowded incisors possibly leads to dehiscence of tissue when tooth is aligned
inadequate attached gingiva
Smile analysis includes
Social smile and emotional smile
full smile wants ___% incisal display
100%
____= distance btw max posterior teeth and inside of cheek (ideally minimal as possible)
buccal corridor
smile arc is contour of upper anterior incials in relations to ____, the goal is ___
curve of lower lip during social smile
match contour of lower lip
All the following are ____:
tooth proportions
golden proportion
height/width of max centrals
width of tooth should be 80% height
gingival height/shape/contour
connectors and embrasure (black triangles)
MICRO-aesthetics
For lateral cephalometric x-rays you evaluate
dentofacial proportions and clarify the anatomic basis for a malocclusion
Study casts allow eval of
arch length
Bolton = tooth size discrepancies
Bite registration
____ = don't want to move teeth around because prone to perio problems
Diabetics
Facemask therapy is used with ____
Class III underbite = pulls UPPER jaw forward
E line =
Nose to Chin
analysis of width of teeth and add them up to compare upper to lower jaw
Bolton Analysis
____ is the space mesial to canine in the max and distal to the canine in the mand
Primate space
____ is the difference between space needed and available for incisors
incisor liability
where does extra space for incisors come from
dental arch increase in width
labial positioning of the central permanant incisors
canines move back in mandibuar arch
Permanant canines and premolars are smaller than primary and result in ____
Leeway space
___ is used for correction of crowding and molar drift
leeway space
mesial migration closes space by ____
holding molars back (lower lingual holding arch)
to measure space available
measure arch perimter from 1st molar to other 1st molar
over contact points of posterior teeth and mesial edges
ehat are the 2 ways to measure
divide dental arches into straight line segments
or contour a peice of wire for measurment all at once
Amount of space required measured by ___(3)
mesiodistal of each tooth
contact pts to contact pt
sum width of individual
3 assumptions of space analysis
1. Anterioposterior position of incisor is correct
2, space available does not change due to growth
3. teeth present and normal sized
An arch length analysis for mixed dentition estimates if there is enough space for ____
permanant canines and premolars if molars are held in current position
only done in lower arch
mixed analysis helps determine
extraction cases
post treatment incisal stability
only in lower arch
3 most common analyses
direct
estimation from porportional table
Johnston-Tanaka and Hixon-Oldfather
Use ____ when trying to discriminate between cases with just enough space for canines and premolars, and severely crowded cases
Mixed dentition analysis
Direct measurment by radiograph uses
periapical
must compensate for picture enlargment
analysis with little predictive value but can assess crowding
direct measurment
lower canines and premolars need at least
23 mm spacing
____ uses average of erupted teeth, no x-ray, measures SA (MD of 4 lower incisors and CDE space of each side) and SR (width of 4 lower incisors + 21 (= width of 3+4+5)
Johnston-Tanaka
____ is combo of radiographs and predicitive table, SA-SR (Direct measure of 4, 5 from periapical and incisors from cast), predicts unerupted canines and uses predictive graph = best predictive method
Hixon-Oldfather
analysis good for a combo of all ethnicities
direct measure of radiograph
If SA=SR what must be preserved
Leeway space to prevent mesial migration
If SA<SR by 1-4 mm (crowding) then
space regaining mechanics
i.e. headgear, expansion and lip bumper
If SA<SR by 5+mm (crowded)
tooth mass reduction by interprox rediuction or extraction
_____ = borrow leeway space, remove lingual sheath, place contact area @ incisal 1/3, adjust at 6 months
Lower Lingual Arch preservation
T/F Arch length analysis can be done with mixed dentition
True
___% of US population have size difference in teeth
5%
Most common tooth size discrepancy =
Lateral max incisors (Peg)
tooth size analysis from permanant dentition =
Bolton Analysis
less than ____ tooth size discrepancy is rarely significant
1.5mm
Standardized radiographic head film with reference landmarks to make measurements
Cephalometrics
Cephalometrics are used to diagnose and treat by evaluating ____
dentofacial proportions and clarify anatomic basis for malocclusion i.e. how the major components of the face realte
cephalometrics are used in ortho to
diagnose and treat
growth eval
treatment eval
treatment prediction
x-ray to patient midsaggital place distance
5 ft
pt midsaggital place to cassette
15 cm
Any malocclusion is result of ____ between ___ and ____ which is affected by jaw relationshp
interaction
jaw position
position of teeth
cephalometrics can
distinguish between skeletal and dental contribution to malocclusion
_____ is produced by:
protrusion of max teeth
mandibular dificiency
downward/ backward rotation of mandible from excessive verticle growth of maxilla
Class II Division I malocclusion
Most important clinical use of cephalometrics
evaluation of ortho treatment
i.e. growth and treatment
3 major cephalometric superimpositions
SI on anterior CB along SN line
SI on maxilla
SI on mandible
what is the objective of cephalometric analyssi
visualize skeletal and dental contributions to malocclusion
13 major cephalometric landmarks
sella (S)
nasion (N)
basion (B)
Articular (Ar)
Porion (P)
Orbitale (Or)
Anterior Nasal Spine (ANS)
Posterior Nasal Spine (PNS)
Point A
Point B
Pogonion (POG)
Menton (Me)
Gonion (Go)
lowest point of anterior margin of foramen magnum
Basion
Intersection point between shadow of zygomatic arch and posterior arch of manibular ramus
Articular (Ar)
Midpoint of upper contour of Ext Auditory Canal
Porion (P)
Inferior part of orbital
Orbitale
Inner most point on contour of premaxilla between anterior nasal spine and upper incisor
Point A
Innermost point on contour of mandible between incisor tooth and chin
Point B
most anterior point or contour of chin
pogonion
most inferior point on mandibular symphysis
Menton
midpoint of contour connecting Ramus and body of mandible
Gonion
Cephalometric reference planes
anterior cranial base - sella - nasion
franfort
palatal
occlusal
mandibular
facial (nasion-pognion)
E plane = nose tip to pogonion
SNA = AP of maxilla and cranial base
>82 degrees =
< 82 degrees
maxilla forward
maxilla back/recessed
SNB = AP position of mandible to cranial base
>80 =
<80 =
prognathic mandible (protrusive)
retrusive = retronagthic
ANB =
differences between SNA and SNB
>2 ANB =
<2 =
Class II = overbite (retronathic mandible)
class III = mandible ahead of maxilla = pronathic mandible
High steep mandibular plae angle =
openbite
low mandibular plane angle
deepbite
IMPA =
Incisor Mandibular Plane Angle
mandibular plane and long axis of lower incisor
larger than 90 degrees = proclination of lower incisor
Analysis where a well proportioned face has horizontal planes converging at 1 point
Sassouni Analysis
Treatment Goals with cephalometrics
ideal OJ/OB, coincident midlines, class I molars and canines, coordiate arches and facial aesthetics
Surgical options =
maxilla
maxilla + genioplasty
maxilla and mandibular (+genioplasty)
mandible oinly ( genioplasty)
Analysis which includes:
REF planes, NA perpendicular, Harvold analysis, mandibular position, U1 = point A perpendicular, L1 = A-Pog (rickets)
McNamara's Analysis
Analysis of Max and Mand lengths
Harvold's
Tangent side (away from movement) stimulates=
side that tooth is moving towards stimulates ___
osteoblasts
osteoclasts
5 mechasnical concepts in Ortho
force
center of resistance
center of rotation
Moment (want this to be minimal)
couple
_____ occurs when force applied to center of mass
bodily movement = good
____ = point of concentrated resistance to movement
Center of Resistance CR
for a tooth, the CR is located
embedded portion - root
Normal location of CR =
1/3-1/4 between alveolar bone and apex of root
multirooted teeth = furcation
Force appled x distance (F x D)
Moment M
if there is further distance the moment will be ____, thus you must decrease ____ so dooth does not tip
greater
force applied
you can cancel the moment by ___, thus producing bodily movement
coupling C
_____ is 2 forces aplied in equal magnitude, opposite direction, which produces PURE rotation around the CR
Coupling
how is horizontal movement achieved
by cancelling out the moment by coupling
How do we apply coupling IN the bracket
engage the wire which has shape memory, if bent the wire will go back. The wire will try to straighten and will apply force, producing rotation through coupling
engaging a wire in an angulation bracket thus resulting in angulation is ___
2nd order coupling
engaging a rectangular wire in a bracket slot resulting in inclination is ___
3rd order coupling = torque
The simplest way to determine tooth movement is the ratio between
moment produced by applying force to the crown of tooth Mf and counterbalancing moment generated by bracket coupling
What is the simplest ortho momemnt
uncontrolled tipping
___ is motion of object that has force applied at a distance from CR, and counterbalancing couple to regulate roation
0<Mc/Mf<1
controlled tipping
Controlled tipping has Center of Rotation around
Root apex
____= Mc/Mf = 1
compression of PDL is uniform from alveolar crest to apex
twice as much force as for tipping = 70-120 gm
Bodily movemtn
Root movement applies the greatest stress at __
root apex
force concentrated over small area at apex, light force required 10-20 gm
Intrusive movement
Only tension, no compression on PDL, same force as tipping 35-60 gm
Extrusive movement
Forces for tooth movement:
tipping
50-120
bodily movement
35-60
10-20
extrusion
35-60
bodily movment
root uprighting
70-120
rotation
intrusion
35-60
4 Edward Angle appliances
E Arch
Pin and Tube
Ribbon Arch
Edgewire
Early appliance only used to tip teeth
E-arch
Horizontal slot appliance, excellent root position, and evolved into what we use today
Edgewise
Edgewise Brackets:
Bends In and Out =
Tip and Angulation =
Inclination and Torque=
1st order
2nd order
3rd order
BL inclination =
Torque
you can only apply torque with a ____
rectangular wire
Torque is ____ as each corner applies equal/opposite force
coupling
_____ can change when applying a couple
center of rotation
Stainless steel results in a ___ of strength and ___ in slot size
Increase strength
reduction of slot size
.022 bracket slot advantage
sliding teeth along wire for space closure
.018 bracket slot advantage
torque
Straight Wire Prescription:
Varying bracket thickness =
variation in bracket slot angles (roots)=
cariation of bracket slot inclination (facial)
1st order
2nd order
3rd order
brackets do the work -less bends in wire =
Andrew's straight prescription wire
this bracket has a clip built into the bracket which holds wire in position, is quick, easy and lesss friction
Self ligating brackets
Usual sequence of appliance
diagnose and treatment plan
separation for banding
banding +/- bending brackets
engage arch wire
To place a band, you need to _____ for ____
create space
5-7 days
Usual patients that require banding=
surgery pts
Young Pts
HEadgear with high force
What type of wire is used 1st?
Light wire - never stainless steel
Step 1 involves
LEveling and alignment
Before closing space on fixing Class II molar relationship you must
Align
Wires have ___, teeth will thus ____
memory
conform to shape of wire
3 major steps of comprehensive ortho treatment
1. level and Align
2. Correct molar relationships and space closure
3. Finishing retention
____ is almost always required and may be fixed or removable
REtention = lingual bar or Hawley retainer
Interarch elastics (use of 1 arch) typically used for
Class II
What is needed for Bio response
tooth, healthy PDL, Bone, Applied force
Tooth movement depends on _____
PDL and turnover of Bone (bone biology)
In the PDL, ____ transmits force applied to teeth, the most important being ____
Collagen fibers
Transseptal
Fibroblasts, Osteoblast/Clasts, UNdifferentiated Pluripotent cells, vascular and neural cells, and viscoelastic fluids acting as shock absorbers are all _____
cells found within PDL
Bone turnover depends on ____+____
Systemic and Local Forces
______ are derived from perivascular cells
OsteoClasts
_____ are derived from Undifferentiated mesenchymal cells
OSteoblasts
What are the 2 theories that Local Control of bony changes adhere to
Bioelectric
Pressure tension
The bioelectric theory includes pressure causing flow of current called _____ which signals a change in bone metabolism
Piezoelectricity
What causes bony changes
piezoelectric bursts
ionic migration
fluid flow
____ is important in skelton maintenence and how bone adapts to functional demands
peizo-electric current
____ has little to do with tooth movement
peizoelectricity
2 ways to enhance tooth movement
bioelectric potential
electromagnetic fields
Pressure-Tension generates ___ through PDL
Change in blood flow
Decrease Blood flow and increased Osteoclast Bone resorption
Pressure side
Increase Blood flow and OSteoblast bone deposition
Tension side
Tooth movement occurs in these 3 stages
blood flow alteration
form/release of chemical messengers
activation of cells
Tooth movements Steps:
Force
tooth
PDL/Bone
Bioelectricity, Blood flow, microfracture
OB Tension, OC Pressure
Resorption of bone in front, deposition behind
OC attack _____ during pressure for frontal resorption
Lamina Dura
PDL Changes = Frontal resorption
Light FOrce
Shut off of blood flow to PDL
Hyalinaization = sterile necrosis
cells come from bone marrow, resorption behind lamina dura
delay of movement - followed by rapid move
undermining resorption
possible PDL damage
HEavy Force
____ results from:
Single forece applied
occurs about CR
max rpessure at apec and alveolar crest
min pressure at CR
Tipping
only after a force is applied for ____ do nucleotide levels in PDL increase which stimulate cell differentiation
4 hrs
Threshold for tooth movement force duration
4-8 hrs
3 things ORtho appliances control
Level of force
duration
distribution
PDL remodel time
Lingual fiber remodel time
bone remodel time
90 days
232 days
6 months
3 basic properties of elastic material
strength, stiffness, range
Ideal AW material for ortho =
High strength, High Range, High Formibility
low stiffness
solderable/weldable
Shape memory occurs with ___
Stainless Steel wire
After teeth are sligned ____ resistance is needed
Higher
____ does not have formability because of shape memory= cannot be soldered/welded or applied a hook
Ni-Ti
____ has shape memory in large range, flexible and bends almost 80 degrees and relieves force and goes back to original shape
Ni-Ti
How do you increase length and decrease stiffness
Loops
Optimum ortho movement is produced by
Light, continuous force
What do you use when teeth are very crooked
Ni-Ti w/ light force, high range, flexible arch wire because of shape memory
____ used intrarch for movement of mandible forward
Class II elastics
To move bodily, you must cancel ____ by ____
Moment
coupling
invisalign attachments are for ___
stability and retention
applied couple to try to have root control and movement
___ are used from lingual of upper molar to buccal of lower molar.
Cross elastics
Cross elastics are stong but have a ___
extrusive force