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Terms in this set (207)
_____ is a specialty of dentistry that deals with the diagnosis, prevention and correction of malpositioned teeth and jaws, misaligned bite patterns. It can also focus on modifying facial growth, known as dental facial orthopedics
Ortho means.... dontics refers to....
Ortho= straight or correct
So orthodntics means striaght or correct teeth
First observation of tooth moving appliances is
_______ is the father of modern dentistry and invented the bandolet, the first described ortho appliance
_____ is the father of modern orthodontics
Prevalence of malocclusions were reported to be between ___ and ___%
35 and 95%
*but estimate is only 35-50% need ortho
Palmer notation numbers teeth how?
1-8 in each quad starting from the incisors
A-E for primary teeth
____ tooth is one present at birth. Could be a supernumerary due to aberration in development of dental lamina or could be normal central incisor
*Extraction is not recommended
Formation of primary teeth begin _____ in utero. Calcification begins _____ in utero
Formation begins 6 weeks in utero
Calcification begins 14-17 weeks in utero
_______ is a histologically landmark in primary tooth enamel corresponding to the event of birth
The 1st tooth is usually ____ and erupts around ____ months of age
Usually Mn incisor
Around 6-8 months of age
All primary teeth should be erupted by ____ months of age. Concern if later than ____
Should be erupted by 30 months
Concern if later than 36 months
Sequence of eruption of the primary teeth by letter of tooth is
Central, lateral, 1st molar, canine, second molar. Same in both arches
As a rough guide can use four month rule as eruption timeline guide. What months would each erupt then?
First molars-16 months
Second molars-28 months
Normal features of the primary dentition compared to permanent are
-Spaced anteriors and primate space
-Shallow overbite and excess overjet
-Flush terminal plane
-Vertical; inclination of the incisors
-Ovoid arch form
SPacing of the primary anterior teeth is required for proper alignment of the permanent incisors. Permanents are ___mm wider
In the Mx arch, the primate space is located between the _____, where in the Mn arch the space is between ____
Mx= between lateral incisor and canine
Min= between canine and 1st molar
If the primary dentition has a distal step, it always becomes a CLass
Pattern of exfoliation and eruption of permanent teeth is
1) Elongation of the root of the permanent tooth
2) Resoprtion of the root of the deciduous tooth
3) Movement of the permanent tooth towards the alveolar crest
4) Vertical growth of the alveolar process
2 things need to happen in pre-emergent eruption:
-Resorption: of overlying bone and roots of primary teeth
-Eruption: mechanism itself pushes tooth into created space
Normally, the rate of tooth eruption is such that the apical area _____ while the crown ____
Apical area remains at the same place while the crown moves in the occlusal direction
______= rapid eruption to occlusal surface after gingival penetration then, as teeth occlude, process slows considerably
Post emergent spurt
_______= eruption matches vertical Mn growth during adolescence
Juvenile occlusal equilibration
_____= after growth has stopped, rate of attrition during adulthood
Adult occlusal equilibration
A post emergent spurt typically has ___mm over 6-8 weeks
4mm. Mainly 8pm-1am overnight
What is the diff between active and passive eruption?
Active: tooth moves in direction of occlusal plane
Passive: exposure of tooth by apical migration of gingiva
The primary dentition is relatively stable from ____ years of age. Early phase of the mixed dentition is when ______. Late phase of mixed dentition is when ______
Stable from 3-6 years of age
Early phase= first molars and incisors present
Late phase= Canines, premolars and second molars present
Sequence of eruption of the permanent dentition with palmar notation is....in Mx and Mn
Mx= 6, 1, 2, 4, 5, 3, 7, 8
Mn= 6, 1, 2, 3, 4, 5, 7, 8
What is the 3 year rule used for in tooth development?
For one specific tooth from crown completion to eruption to root completion
Ex: 1st molar= 3 yrs of age crown complete, 6 years eruption, 9 years root completion
At the dental age of 8 what should we expect to be erupting?
At the dental age of 6 expect what to erupt?
Min centrals, Mn and Mx first molars
Teeth usually emerge with ____ of the root formed
______ in sequence of eruption is much more of a concern than general delay or acceleration
A permanent tooth on one side generally erupts within ___ months of its counterpart on the other side
Essential factors for a smooth transition to permanent dentition are
-Normal sequence of eruption
-Tooth size and jaw in harmony
Permanent anterior teetha re each ____mm wider than primaries which is why general spacing is important in the primary dentition
The leeway space per quadrant is
Mx= 1.5mm each quad so 3mm total
Mn=2.5mm each quad so 5mm total
What is early mesial shift?
Mesial migration of the erupting Mn permanent molar, uses the Mn primate space and occurs around 6 years of age
What is late mesial shift?
Mesial migration of erupted Mn permanent molar after the loss of primary second molar
Uses leeway space and occurs around 11 years of age
If you have premature loss of primary second molars ALWAYS consider
Using a space maintainer until arrival of second premolar
______= transitional crowding, erupting permanent incisors are larger than the space available at that time
When incisor liability happens, solutions that the mouth does are
Expansion at the canines
Proclination of the anteriors
Space primary dentin
Use Mn primate space
A transitional 1-3mm ____ is very common the the anterior teeth and usually resolves with eruption of permanent canines
*Diastemas less than 2mm usually resolve on their own
The "Ugly duckling" phase involves
-Midline diastema often present
-Distally angled Mx incisors
-Teeth upright and space closes with eruption of canine
How does a Class I molar relationship develop?
Often have a mesial step in primary dentition that resembles Class I
If flush terminal plane in primary the Mandible can move forward for a Class I
*If Mn grows significantly then could result in Class III
If a child had over retained primary teeth what should you do?
Try to have them wiggle out primaries and if they can't , removal of primary teeth allows for spontaneous correction
If a tooth is ankylosed, you need to consider how much growth is remaining for the child? If minimal growth.....If substantial growth....
Minimal growth= maintain tooth to keep bone for a possible implant later
Substantial growth still= extract the tooth cause if you don;t could create a vertical defect
What is the difference between growth and development?
Growth= increase in size or number. Anatomic phenomenon
Development= Increase in complexity or specialization. Progress towards maturity. Physiologic and behavioral phenomenon
______ refers to a description of the average changes in craniofacial structures that occur with growth on the GROUP/POPULATION level
_____ refers to the string tendency for certain skeletal relationships within the face to remain constant with growth (Class II growers tend to maintain Class II growth) at the INDIVIDUAL level
______= structures farther away from the brain tend to grow more and longer than those which are closer to the brain
Cephalocaudal gradient of growth
How do the different planes of the face grow generally?
-Transverse dimension of the face/jaws stops growing soonest(width)
-AP dimension stops next
-Vertical dimension grows the longest
Growth of the jaws falls between the _____ and _____ growth curves
Neural and general growth curves
The _____ follows the general body curve more closely than the ____
Mandible follows general body curve more than the maxilla
What growth variability is of concern and should further study that individual?
Look for deviation from the usual pattern-Patients outside 2 standard deviations (97%) may warrant further study
How do we know when the adolescent growth spurt (peak growth velocity) will occur?
Look at: Chronolgical age, dental age, puberty, skeletal maturation
The _______ is the most obvious and easily determined. Calculated from the child's date of birth. Wide variation in indictable timing of pubertal growth spurt
WHat are the 3 stages girls go through with puberty?
Stage 1: Starts at the beginning of physical growth spurt
Stage 2: PEAK velocity. 1 year after stage 1. Secondary sexual characteristics develop(breasts, pubic and axillary hair)
Stage 3: 1-1.5 years after stage 2. Onset of menarche. Growth spurt complete
What are the 4 stages boys go through in puberty?
Stage 1: Fat spurt
Stage 2: 1 year after stage 1. Spurt in height. Decrease in subcutaneous fat
Stage 3: PEAK velocity. 8-12 months after stage 2. Facial Hair. Increase in muscle mass
Stage 4: 15-24 months after stage 3. Growth ends
What are the three parts of the Hand-wrist that you can look at to determine skeletal maturation?
Sesamoid, middle pharynx of 3rd finger, radius
If ossification of the sesamoid part of the thumb area has not occurred then
PRE-peak growth rate
When looking at the middle pharynx of the 3rd finger, what signifies pre-peak velocity, peak velocity, and growth complete in skeletal maturation?
Pre-peak velocity= WIDENING of the epiphysis
Peak velocity= CAPPING of the epiphysis
Growth complete= FUSION of the epiphysis
If fusion of the radius is attained then
Growth of the skeleton is nearly complete
Can we predict the timing of an adolescent growth spurt(peak growth velocity)?
Probably NOT for any given individual
-Can take our best guess
Average growth predictions (between age 7 and 25) indicate...
-Strong tendency to maintain overall facial type
-Normal pattern of growth is favorable towards Class II correction(later Mandibular growth)
-Class III tendencies can worsen with age
-Malocclusions rarely correct spontaneously
What is the difference between and infant and adult in terms of
-Forehead: child=upright and bulbous
adult=more sloping back
-Eyes: child=Large and wide set relative to the face
Adults=not much wider
-Ears: child=appear low
Adult=move down during growth
-Nasal region: child= vertically shallow
Adult=large vertical and lateral expansion of the nasal sinus
-Mandible: child= proportionally underdeveloped and recursive, more V shaped
Adult= more U shaped
____ of all growth is competed by age 10-12 so before ortho tx
______= increase in size of individual cell
_______= increase in number of cells
_____= increase in size independent of number or size of cells
Secrete extracellular material
_____ parts of the body usually grow by interstitial growth versus ____ grow by surface apposition
Soft tissues and most cartilage=interstitial
Hard tissues like bone and some cartilage=surface apposition
_________ ossification= cartilage is transformed into bone
_____ ossification= secretion of bone matrix directly within connective tissue without a cartilage intermediate
_____ of bone often drives modeling and remodeling
Modeling = ____ bone
Remodeling= ____ bone
Modeling = NEW bone
Remodeling= EXISTING bone
Growth in the ____ is entirely the result of periosteal activity at the inner and outer surfaces of the bones(cortical drift) and apposition along cranial sutures or fontanelles
What happens to bone on the interior vs exterior of the cranial vault?
Removal of bone on the inner surface
Addition of bone on exterior of cranial vault
Formation= entirely Intramembranous bone
Controlling factors= Brain development
In microcephaly what is happening?
Brain stopped growing so no need for cranial vault to grow so childs head is very small
With cranial vault growth, the anterior cranial fossa grows ____ due to cortical drift of frontal bone
Also, frontal sinus _____ and frontal prominence _____
anterior cranial fossa grows FORWARD due to cortical drift of frontal bone
Also, frontal sinus INCREASES in size and frontal prominence INCREASES
Formation= Endochondral ossification to bone
Controlling factors= Brain development, olfactory area
Due to the cranial base, the middle cranial fossa grows ____ and ____ leading to displacement of Mx and Mn ____ and _____
DOWNWARD and FORWARD
Majority of endochondral cranial base growth completed by age
Formation= Intramembranous (surface remodeling of anterior surface and palate-apposition of bone at sutures connecting cranium and cranial base)
Controlling factors= Airway/sinus and naso-cartilage
Growing of the masomaxillary complex leads to
Hard palate and base of nasal cavity move downward (cortical drift)
Increase in nasal passage leading to increased Mx vertical dimension
The mid-palatal suture is opened until _____. It is important to know this because...
13-15 years old
Important to know because is posterior cross bite, correct it before the sutures close
Principal sites of growth in the Mandible are
-Posterior surface of the ramus(increase length of Mn)
-Condylar and coronoid processes(increase vertical height of ramus)
Formation= Primarily intramembranous bone formation, but both endochondral(condyle) and periosteal activity are important for Mn growth
Controlling factors= Condylar cartilage?, function(pharynx and tongue)
-_____ of ramus along anterior border happens during growth for _____
-_____ on posterior border of ramus in order to maintain ramus size
-_______ growth at condyle and coronoid process leading to displacement of Mn ____ and ______
-RESORPTION of ramus along anterior border happens during growth for SPACE FOR MOLARS
-BONE DEPOSITED on posterior border of ramus in order to maintain ramus size
-UP AND BACKWARD growth at condyle and coronoid process leading to displacement of Mn DOWN and FORWARD
Growth of the face in three planes of space happens in what order?
1) Width= completed first (age 12, before growth spurt), includes width of dental arches
2) Length= continue to grow through puberty (age 14-15 females)
3) Height/vertical= can continue through adulthood
How does lip growth relate to growth of jaws?
Grows later and longer than jaws. The catch up alter (can be reductio of "gummy" smile
-Increase in thickness in adolescence and vertical dimension
Growth of the nasal bone completed around age _____. Growth of nose after this only due to...
Growth of nose after only due to cartilage and soft tissues
Maturationa nd aging changes bug features of the face include
-Decreased incisor show on smile
-Decrease lip fullness
-Increase Mn incisor crowding
____of growth is a location where growth occurs(sutures)
____ of growth is a location at which independent, genetically controlled, where growth is initiated
Condyle is a growth _____
_____ and ____ are the two tissues that comprise the skeleton
Cartilage and bone
In correlation to age, how does bone formation nd bone resorption differ over time?
Age 0-20 BF>BR
Age 20-50 BF=BR
Age >50 BF<BR
There are two types of bones and how are each formed?
Flat bones- formed by intramembranous bone formation
Long bones-endochondral bone formation
_____ ossification is a complex multi step process requiring the sequential formation and degradation of cartilaginous structures.
Endochondral - important for postnatal growth, fracture repair and bone modeling
What are the components of bone?
What does the 60-70% inorganic component of bone include?
-acts as a reservoir for calcium, phosphate and magnesium ions
90% of the organic matrix of bone is composed of
Type I collagen
What other collagen types besides I are present in bone ECM?
III, V, X, XI
Osteoblasts are ___ shaped on the sides of cells
The main function of an osteoblast is
Secretion of a complex mixture of bone matrix proteins(osteoid)
The other four functions of osteoblasts besides Secretion of a complex mixture of bone matrix proteins(osteoid) are
2) Regulate mineralization of osteoid
3) Effector of systemic mineral homeostasis
4) Endocrine regulator of glucose metabolism
5) Local regulation of osteoclastic differentiation and bone resorption
Osteoblasts have three possible fates which are...
1) Become embedded in bone matrix and become an osteocyte
2) Bone lining cell, involved in maintaining bone formation and resorption dynamics
3) Apoptosis(Cell death)
______: found deeply embedded in bone. Orginally osteoblasts which become trapped in the bone. Serve role as a ______
Serve role as a mechanosensor
_______= bone lining cell responsible for bone resorption. Found in contact with the bone surface and in Howship's lacunae. Usually ______ osteoclast per resorptive site
Usually one or two osteoclast per resorptive site
The first sign of bone resorption is ______ and then osteoclasts can attach. Then become polarized and form a ____ zone. Causes resorption, detachment and cell death
First sign= retraction of bone lining
Form sealing zone
The resorptive space is highly ___, producing ____ within the space
Why do we need to resorb bone?
To replace the old, worn out bone by new bone tissue. Releases calcium and phosphate trapped in the bone. Used for helping of bone fractures, eruption of teeth and ortho tooth movement
What is the role of RANKL?
Stem cell binds to RANKL and causes differentiation of osteoclast
What blocks osteoclast differentiation?
OPG binds to RANKL and blocks osteoclast differentiation
During bone remodeling, where do RANKL activator cells of osteoclast differentiation come from?
Osteocytes have them attached so they can remodel bone with osteoclasts
Inflammatory cytokines such as ___ and ____ also promote osteoclast formation
Bone remodeling occurs in a sequential manner, often referred to as the _____ cycle
Activation-Resorption-Formation (ARF) cycle
What mechanisms recruit osteoblasts to sites of resorption?
-Factors released from bone matrix (BMPs, TGF-beta, etc)
-Ephrins(cell to cell communication)
-Factors released by osteoclasts (S1P, Cthrc1)
What does Wnt and Wnt antagonists do?
Wnt= induce bone formation and osteoblastogenesis. Suppresses osteoclastogenises and bone resorption.
This is a good target for glucocorticoid induced osteoporosis
What is sclerostins role in bone formation?
It is a ligand for LRP5 and prevents Wnts from activating bone formation
-Lack of sclerotin can lead to high bone mass disease.
Sclerotin is produced by mature osteocytes
What are current therapies used to treat osteoporosis?
Estrogen and gonadal steroids
How do sex steroids play an important role in bone cell metabolism?
* Overall function=maintain a steady state in bone metabolism to prevent bone loss
Regulate osteoblast and osteoclast activities. Reinforce coupling of these cells through other paracrine factors
At menopause how much bone loss do women undergo and how long?
Rapid trabecular bone loss period that can last 5-10 years. 8-10 years after menopause, a second slower and continuous phase of bone loss occurs where trabecular and cortical bone is lost for the rest of her life
What do glucocorticoid drugs do to bone?
Generally used to treat asthma, rheumatoid arthritis and other inflammatory diseases
-Reduces osteoblast activity so fracture prevalence for adults taking these for 5 years or more is 30%
____ drugs inhibit bone resorption by osteoclasts. Would be expected to inhibit ortho tooth movement
bisphosphonate (either nitrogen containing-affecting ruffled membrane required for bon resorption or non-nitrogen-metabolized in osteoclast resulting in cell death)
What us the use for denosumab(prolia)?
Bone metastases, treatment induced bone loss, multiple myeloma, and bone erosion and RA
Less reactions then bisphosphonates
If you want to decrease the expression of sclerostin(as it prevents bone formation by prevent Wnts) then you could
Give PTH treatment
-PTH treatment and mechanical stimulation reduced expression of sclerostin which lead to increased bone formation
Antibodies against ____ have also shown promise in treating osteoporosis
Under normal circumstances, the PDL is ____mm in size
With intermittent/heavy forces(1 sec or less) of occlusion how does the PDL respond?
-Fluids and ligaments stabilize against gross dispalcement
-Alveolar bone bends
With light/steady forces(soft tissue pressure) of occlusion how does the PDL respond?
Can lead to minor tooth movements (no pain)
Phsyiological took movement happens how...
1) Normal process, very slow (years)
2) Primarily a periodontal phenomenon
3) Not associated with inflammation/pain
Orthodontic tooth mouvement happens how...
1) mechanically induced
3) Primarily periodontal phenomenon
4) Use light, prolonged pressure and tooth moves then bone around tooth remodels
5) Often associated with some inflammation/pain
The two types of bone remodeling are
1) Frontal resorption
2) Undermining resorption
-Occurs in regions of LIGHT forces
-Osteoclasts derived from PDL blood vessels
-Bone resorption of lamina dura occurs on FRONTAL surface
-Survival of MOST cells in PDL, relatively painless
-Occurs in regions of HEAVY forces
-PDL compressed, localized blood flow stopped(NECROSIS)
-HYALINIZATION occurs in PDL
-Osteoclasts derived from trabecular bone spaces
-Bone resorption is DELAYED, resorption of lamina dura is from arrow surface
-Typically associated with more PAIN
There is a _____side of ortho tooth movement and a _____side.
Tensiona nd compression
-NUmber of osteoclasts ______, derived directly from blood,
-Bone is ______
-Takes about _____ to initiate a cellular response within the PDL space and 2-5 days to initiate ________
-NUmber of osteoclasts INCREASE, derived directly from blood,
-Bone is RESORBED
-Takes about 4-6 HOURS to initiate a cellular response within the PDL space and 2-5 days to initiate BONE REMODELING
-Number of osteoblasts/fibroblasts _____, derived from mesenchymal cells
-Fibroblasts remodel the collagen/PDL fibers
-New osteoid is laid down
-TIming ______ resorption
-Number of osteoblasts/fibroblasts INCREASE, derived from mesenchymal cells
-Fibroblasts remodel the collagen/PDL fibers
-New osteoid is laid down
-TIming LAGS BEHIND resorption
A patient must wear a removable appliance AT LEAST ___ hours to initiate ortho movement
Clinically, with orthodontic movement see what?
-Rapid movement within hours
-Then steadies off for two weeks in LAG PHASE and then after can initiate movement again in POST-LAG PHASE
What happens in the LAG phase of ortho movement?
-Little or no tooth movement occurs, with exception of some settling in the PDL space
-Undermining resorption occurring(waiting for resorption of lamina dura)
-Can extend up to 2-3 weeks
What happens in the POST LAG phase of ortho movement?
-Lamina dura has been resorbed and tooth movement begins again
-Bone resorption continues primarily through frontal resorption
-Process can continue for extended periods of time if steady/light force levels can be maintained
How do each of these tissues change with ortho movement?
Enamel: No effect
Cementum: Localized perforations, repairs
Dentin: Resorption in areas of cementum, perforation possible(repaired with cementum)
Pulp: Modest and transient inflammation - potential loss of tooth vitality in history of trauma and endo treated teeth CAN be moved
How do each of these tissues change with ortho movement?
PDL: Compression of blood vessels/fibers on leading side. Dilation of blood vessels/stretching fibers on back
Bone: Alveolar bone remodeled, bone RESORPTION in zones of COMPRESSION and bone deposited in zones of tension
What are the different types of force application and how long is there duration and decay?
-Continuous forces= NEVER declines to zero, NiTi coil spring
-Interrupted forces: Declines to zero(has recovery periods), Power chain
-Intermittent forces: Declines to zero, Removable appliance)head gear, elastics)
The longer the force is applied, the more the teeth will move. Need ___ hours at least per day in mouth
4-6 hours at least
The force magnitude in ortho is _____ grams
______ forces are currently considered to be the most effective at inducing tooth movement
Heavy forces on ortho generally increase risk of
The simplest force when applied on a crown to move is
There are 6 types of forces. order them by amount of force needed
Bodily movement (translation)(70-120gm)
Medications: ____ and ____ can increase ortho tooth
Prostaglandins and Vitamin D
Short term use of ____ for acute pain has no relevance for ortho but LONG terms would be expected to DECREASE ortho tooth movement
Traditionally cephalometric X-rays usually went off of the ______ plane but the natural head position is actually better but....
Used to go off Frankfort plane
Head position better but HARD to standardize between different patients
Why are cephalometric radiographs important?
-Limitations of dental casts
-Evaluation of skeletal and dental relationships/etiology of the malocclusion
-Discovery of ortho treatment changes/effects
-Provides indication of future growth potential and direction
Cephs are NOT good for _____ Screening
Pathology(so other x rays still important)
A steep mandibular plane angle correlates with ______ anterior facial vertical dimensions and _____ malocclusion
LONG anterior facial dimensions and ANTERIOR open bite malocclusion
What information can we get from a FRONTAL AP cephalometric?
-Mx/mn transverse discrepancies
-Porportions and ratios (vertical relationships, horizontal relationships, asymmetries)
Which of the following are uses for cephalometric in orthodontics?
Analysis of treatment results
longitudinal studies of growth
ALL of the above
The goal of a cephalometric analysis is to
-Evaluate the relationships of the 5 major functional components of the face(Cranial base, maxilla, mx teeth, mn teeth, mandible)
-Recognize and evaluate changes/results from ortho tx
-Assess facial growth
-Comparative analysis to other populations
-Relate to changes over time of same individual
In a cephalometric analysis, for soft tissue we look at
Facial contour, proportions, lip positions
The goal when doing different analyses is to have all of
the data sets match (whether you compare to race, ethnicity, normal distribution, have them all match)
What is the tracing technique for a cephalometric radiograph?
Start by tracing soft tissue profile, then cranial base. Then maxilla and related structures, then mandible and related structures
Trace the average of bilateral structures(ex: inferior border of Mn)
Most anteriorly positioned incisor is traced too unless grossly displaced in comparison to other incisors
Anterior nasal spine, the anterior tip of the sharp bony process of the maxilla at the lower margin of the anterior nasal opening
Articulate-point at the jxn of posterior border of ramus and the inferior border of posterior cranial base
Basion, lowest point on the anterior rim of foramen magnum
Gonion- the midpoint of the curvature of the angle of the mandible connecting the posterior ramus and the inferior border of the mandible
Gnathion- point between the anterior Pog and inferior Me points of the bony chin
Mention-the lowest point on the symphyseal shadow of the mandible
Nasion-most anterior point on the pronto-nasal suture in the mid-sagittal plane
Orbitale-lowet point on the inferior rim of the orbit
Posterior nasal spine-posterior spine of the palatine bone constituting the hard palate
Pogonion- the most anterior point on the bony chin (chin button)
Porion-most superiorly positioned point of the external auditory meatus
Subspinale= most posterior midline point of the concavity between ANS and most inferior point on the alveolar bone overlying Mx incisors
Supramentale-most posterior midline point in the concavity of the mandible between the most superior point on the alveolar bone overlying the incisors and Pog
Sella-the geometric center of the pituitary fosse
Frankfort horizontal- plane through orbital and porion
Sella-nasion, plane through sella turcica and nasion
Facial plane- plane through nasion and pogonion
Occlusal plane-plane through terminal molar and split in center between upper and lower incisors
Mandibular plane- plane through menton and gonion
Esthetic line-line touching soft tissue nose and chin which gives assessment of upper/lower lip projection
What are SNA and SNB values used for?
Assessment of AP position of maxilla and mandible to anterior cranial base
Normal values of SNA and SNB are
SNA: 82 +/- 4
SNB: 80 +/- 4
What does an SNA angle less than 82 degrees signify if 82 is the normal value?
Maxillary retrognathism (maxilla further back than usual)
If the SNA values or SNB values are less than their given normal value that means
retrognathic respectively to either jaw
If the SNA values or SNB values are greater than their given normal value that means
prognathic respectively to either jaw
What does ANB tell us in cephalometrics?
General idea of the AP discrepancy of the maxillary to the mandibular apical bases
ANB normal value is
2 +/- 2. If larger value than this mean that apical bases far apart from each other
A-NP signifies what?
A point of the maxilla in relation to the cranium and upper face.
Normal: 0 +/- 1
(should have A point pretty parallel to nasion)
Facial angle(FA) means
A-P position of the mandible in relation to the cranium dn upper face. Angle in which the facial line (Nasion to Pog) intersects the FH(Frankfort horizontal)
Normal FA is 88 +/- 3.5. If angle is 84 what does that mean?
Mandible is retrognathic(farther behind the nasion than normal.
Mandibular plane angle is a vector of growth and key indicator of ______. It is the angle between the Mn and ______
Key indicator of case difficulty
Angle between Mn and Frankfort horizontal
Normal MP is 22+/-4. If 26 then
steeper plane of the Mandible
A well balanced face has what UFH(upper face height) and LFH(lower face height) %
UFH is measured by
Nasion to ANS(anterior nasal spine)
LFH is measured by
ANS to Me(Menton)
Mx incisor to SN(sella nasion plane) is normally 102 +/- 5. If it is 111 then
protruded maxillary incisors
Md incisors to MP(mandibular plane) is usually 90+/-4. If it is 102 what does that mean?
Protruded Mn incisors
Maxillary incisor and Mn incisor AP position is an assessment of
amount of incisor protrusion
Normal=4mm Mx incisor to NA line and Md incisor to NB line
Interincisal angle is an assessment of
Degree of incisor proclination
E plane should have lips..
BEHIND the plane, to the left.
Norm=-4 upper lip, -2 lower lip
An acute angle for the nasolabial angle from base of nose to tangent of upper lip may indicate
If ANB value is negative what does that indicate?
Class 3 patient, mn incisors in front of mx incisors
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