Ortho Flashcards
The Foramen Magnum presents which two midline cephalometric landmarks?
The OPISTHION is the midpoint on the POSTERIOR MARGIN of the foramen magnum.
The BASION is located at the midpoint on the ANTERIOR MARGIN of the foramen magnum.
What are the Cranial Base planes?
CRANIAL BASE PLANES
Base located on Cranium
- Basion-nasion (Ba-N)
- Sella-nasion (S-N)
- Frankfort horizontal plane (Po-Or)
What is the Frankfort Horizontal Plane?
PO
βFrank drove to the Post-Officeβ
ππ β
FRANKFORT HORIZONTAL PLANE
A cephalometric plane joining the anthropometric landmarks of PORION and ORBITALE
the reproducible position of the head when the upper margin of the EAR openings and lower margin of the orbit of the EYE are horizontal.
used to orient a human skull or head usually so that the plane is horizontal
β called also eye-ear plane,
What is a cephalometric plane?
A PLANE by definition connects THREE or more points.
A LINE by definition connects TWO or more points.
These two terms are often used synonymously.
Skeletal Crossbites most frequently occur in what skeletal class occlusion?
πππ
SKELETAL CROSSBITES BOTH ANTERIOR AND POSTERIOR.
CLASS 3 πππ
Excess OVERJET is usually accompanied by what Skeletal class?
CLASS 2
A deep OVERBITE is usually associated with which skeletal class?
CLASS 2
FINGER SPRING ACTIVATION
SINGLE CANTILEVER
USES:
2-3 mm of Activation
1mm/month
Single Cantilever
- One helixes
- One activation arm
- Usually MD movement
HELIX should be OPPOSITE to the DIRECTION of INTENDED tooth movement
Z-SPRING
DOUBLE CANTILEVER
Z-SPRING
DOUBLE CANTILEVER
- Second Beam with a Second Helix
- 2mm of activation per Helix
- Usually FL direction
Canine relationship.
What does it best predict?
Canine Relationships:
BEST PREDICTOR of SAGITTAL relationship into the permanent dentition.
- Mesial step canines - usually results in Class I relationship
- Distal step / End-on canines - usually results in Class II to end-on permanent dentition
- Excessive mesial step (with incisor crossbite) - usually results in Class III permanent dentition
Normal: Class 1
The maxillary canine occludes with the distal half of the mandibular canine and the mesial half of the mandibular first premolar.
Distal: Class 2
β¨The mesial incline of the maxillary canine occludes ANTERIORLY with the distal incline of the mandibular canine. β¨The distal surface of the mandibular canine is POSTERIOR to the mesial surface of the maxillary canine by at least the width of a premolar.
Mesial: Class 3
Distal surface of the mandibular canines are mesial to the mesial surface of the maxillary canines by at least the width of a premolar.β¨
How long should a Thumb Sucking Appliance be worn?
Generally, a thumb or finger sucking habit will be broken in 6-8 months. During this 6-8 months, dental changes such an open bites tend to close spontaneously.
For most MILD to MODERATE thumb sucking habits this will be 3- 6 MONTHS of total wear.
A PERSISTENT thumb sucker wears a device for thumb sucking for up to a YEAR. In cases where a thumb sucking habit returns after initial treatment a new habit appliance is fabricated.
Thumb-sucking habits are normal reflexes from birth to three years of age. The majority of children naturally outgrow their thumb-sucking habit between two and four years of age. Aim to encourage halting the habit by age three. However, habits that persist after the age of five or six risk oral complications.
What is a Herbst Appliance used for?
β¬
οΈ
β‘οΈ
π
CLASS 2
The Herbst appliance moves the β‘οΈ LOWER JAW FORWARD β‘οΈ while putting β¬ οΈ BACKWARD PRESSURE on the UPPER JAW β¬ οΈ It attaches to the back molars on both sides of the upper and lower jaws. It is often used a long with braces.
Normally, the appliance is worn for at least 12 MONTHS π. Improvement in bite and appearance can usually be seen much sooner.
What is the Sagittal Plane?
The sagittal plane is an anatomical boundary that exists between the left and right sides of the body. The sagittal planes runs PARALLEL to the LONGITUDINAL AXIS of the organism, or from the mouth to the tail.
What markers determine the Vertical Dimension (Facial Height)?
Nasion-Menton
70% complete by age 3.
90% prior to adolescent growth spurt.
Brachyfacial (HYPOdivergent)
growth characteristics
- POSTERIOR β¬οΈ face height GREATER than anterior face height
- COUNTER-CLOCKWISE rotation
- FLAT mandibular plane
- DEEP overbite
Dolichofacial (HYPERdivergent)
Growth characteristics
- ANTERIOR β¬οΈ vertical facial growth greater than posterior condyle growth
- CLOCK β° WISE rotation
- STEEP mandibular plane
- OPEN bits tendency
What facial dimension shows the LEAST amount of change?
WIDTH
Greatest rate observed between 2-6 years
What facial dimension has the LONGEST growth pattern?
DEPTH
(anteroposterior)
Growing rates at different times
(differential growth)
What does the MOYERS and the TANAKA / JOHNSON space analysis measure?
MIXED DENTITION ANALYSIS
They predict the combined widths of the unerupted canines and premolars from the widths of the MANDIBULAR incisors.
Width of 23-26
β¬οΈ
C+1PM+2PM Both Arches
The mandibular incisors were chosen because of their early eruption.
The maxillary incisors π« are not used since they show a lot variability in size.
Remember that the width of the lower incisors is used to predict upper canine and premolars widths too
MOYERS: Mixed Dentition Analysis
-use of probability charts. In the tables, 75% level of probability is used as it is the most practical from a clinical standpoint.
TANAKA / JOHNSON Analysis:
They simplified Moyers 75% level of prediction table into a formula to predicted the width of maxillary canine and premolars (in one quadrant):
πππππ ππππππ; πππππππππ π€πππ‘hπ = π€πππ‘h ππ πππ’π πππ€ππ πππππ πππ + 11ππ
πΏππ€ππ ππππππ; πππππππππ π€πππ‘hπ = π€πππ‘h ππ πππ’π πππ€ππ πππππ πππ + 10.5ππ
What does the NANCE analysis measure?
A method of assessing the arch length for the permanent dentition first defined by H. N. NANCE in 1947.
It is the DIFFERENCE in LENGTH of the space occupied by the
primary canine and two primary molars
PC + P1M + P2M
ββspace diffββ
C + 1PM + 2 PM
and the space occupied by the permanent canine and two premolars on each side of the arch.
What 2 ortho markers are located on the FORAMEN MAGNUM?
BASION (Ba)
-Most anterior point
OPISTHION (Op)
-Most posterior point
What is the BOLTON Analysis?
A
β
A
TEETH - MEASUREMENT - ARCH -COMPARISON
Determines the discrepancy between size of maxillary and mandibular teeth. This analysis helps to DETERMINE the optimum INTER-ARCH RELATIONSHIP.
A
β
A
An Overall Analysis measures the sum of mesio-distal width of all 12 (first molar to first molar) mandibular teeth and compares them to the 12 maxillary teeth. The overall ratio known to be 91.3%.
The Anterior analysis measures the sum of Mesio-distal width of front 6 mandibular teeth and compares them to maxillary teeth. The anterior ratio is known to be 77.2%.
An overall ratio of more than 91.3% means that the mandibular teeth are bigger when compared to normal.
A ratio smaller than 91.3% would mean the mandibular teeth are smaller than normal.
What can Airway compromise/ mouthbreathing due to impact facial growth?
Management options?
β¬οΈ increase vertical dimension / skeletal OPENBITE
-Refer to ENT for possible:
Allergy management
Tonsil/adenoids removal
Followed by PALATAL EXPANSION
Importance of the Sella Turcica in Ortho.
S
It is a saddle-like bony formation on the upper surface of the body of SPHENOID bone.
Seen on LATERAL cephalometric radiographs and sella point is routinely traced for various cephalometric analyses.
During embryological development, the sella turcica area is the key point for the migration of the NEURAL CREST CELLS to the frontonasal and maxillary developmental fields.
The prevalence of sella turcica bridging is high in class III malocclusions and dental anomalies.
What is the general treatment strategy for a DEEP OVERBITE?
Often associated with?
C2D2
EXTRUDE posterior teeth and allow rotation of mandible DOWNWARD.
Maxillary molar extrusion via cervical headgear
CLASS 2 DIVISION 2
Palatal Crib Appliance
Indications?
When?
Length of Treatment?
Interferes with digit placement and tongue π thrust
Once INCISORS are in TRANSITION, 6-10 years of age.
Planned for 6 MONTHS wear, HABIT usually CEASES in WEEKS.
MAXILLA to CRANIUM
Diagnostic Reference?
Angle?
Relation to Film edge?
Maxillary length?
SNA
Sella-Nasion-A point
What is the Downs Analysis?
Balance of face is determined by POSITION of MANDIBLE
- uses FRANKFURT HORIZONTAL PLANE as a REFERENCE plane base (Porion to Orbital)
- by that determines retro, pro, or orthognathism
-FACIAL ANGLE:
-Inside inferior angle
-Uses intersection of NASION - POGONION plane to FH (Na - Pg)
-Average angle: 87.8. +/- 3.5
> 87 = Prognathism
< 87 = Retrognathism
What is the sequence for serial extractions?
βCD4β
MANDIBLE
- Mand Primary Canine
- Mand Primary 1st Molar
- Mand Permanent 1st Premolar
C
D
4
What would be the purpose for using an asymmetric headgear bow? (Unequal arms)
In UNILATERAL CLASS 2 cases if you want to distalize one side.
As the difference in outer bow length became greater, β¬οΈ asymmetric effects increased.
β¬οΈ
Greater distal force in the longer arm side was associated with greater lateral force towards the shorter arm side and more net yawing moment.
When should a Frenectomy be done if the frenulum fibers are causing a diastema greater than 2mm?
Opinion vary but this is an AAPD 2019 article.
βThere is general agreement between pediatric dentists and orthodontists that a frenectomy should not be performed before the PERMANENT CANINES ERUPT and that the operation should follow orthodontic closure of the space.β
What is the Y-Axis on a cephalometric film measure?
Direction of MANDIBULAR growth.
S-Gn (Sella turcica to Gnathion) to the FH plane.
Gnathion - the most inferior point of the mandible in the midline.
Average Angle: 59 degrees
Angle greater > 59: class 2, vertical growth
Angle smaller < 59: class 3, horizontal growth
Functional Shift Anterior Crossbites?
Causation?
Clinical Observations?
Tx?
CAUSATION:
In a growing child, the UPPER ARCH can be UNDERDEVELOPED because of AIRWAY ISSUES or abnormal habits like thumb sucking.
This can lead to an ABNORMAL CONTACT POINT high cuspids that interfere with the childβs ability to close properly and make contact with the posterior teeth.
OBSERVE: (PBSP)
the PRIMATE SPACING in the upper and lower anteriors. In a functional cross-bite, there is usually NO SPACING in the UPPER arch.
A skeletal Class III exhibits normal spacing.
In a functional Class III, the bite is usually deep. In a skeletal Class III, itβs normal or end-to-end.
Size of the maxilla. If narrow and high-vaulted, it tends to be functional.
Mandibular plane angle. If the angle of the mandible appears parallel to the floor, this is indicative of a functional Class III.
TREATMENT:
They donβt go away on their own. This is especially true of functional anterior (Pseudo Class III) cross-bites, and they are especially critical. You must correct them. Opting out makes you the causative factor behind a host of far-reaching, prohibitively expensive problems β most significantly the development of a permanent Class III dentofacial/mandibular abnormality.
Treat it with a REMOVABLE APPLIANCE that will effectively jump the cross-bite by proactively directing the growth of the premaxillary segment and the teeth. You can alleviate the interference points, and allow the maxillary arch to once again encompass the lower arch. That done, the patient has an opportunity to return to normal function.
Leeway Space
What is it?
How much space does it provide?
Leeway space is the SIZE DIFFERENTIAL between the PRIMARY POSTERIOR teeth (canine, first and second molars labeled C, D and E in the picture), and the PERMANENT canine and first and second premolar
Per QUADRANT:
Maxillary space of 1.5mm / 3mm total
Mandibular space 2.5mm / 5mm total
EARLY vs LATE Mesial shifts
EARLY MS:
PRIMATE SPACES
- Occurs about 6 years old
- Incoming 6 year permanent molars
- seen in @65% of patients (those who have primate space)
LATE MS:
- Exfoliation of the Second Primary molars
- Occurs around 11 years old
- seen in ALL patients
Moss Functional Therapy
BONE GROWTH - FUNCTION OVER FORM
Phenomenological description of bone growth.
Soft tissues and capsules drive growth control.
It proposes that βthe origin, development and maintenance of all SKELETAL UNITS are SECONDARY, compensatory and mechanically OBLIGATORY RESPONSES to temporally and operationally prior demands of related functional matrices.
bones do not grow but are grown, thus stressing the ontogenetic primacy of FUNCTION OVER FORM.
How can it be determined that a patients class III malocclusion is dental?
Flaring of the Mandibular Incisors
What is the most common cause of Class III malocclusion?
The most common cause of Class III malocclusions is excessive growth of the mandible.
The molar position of these patients is referred to as mesio-occlusion, whereas the anterior relationship shows a negative overjet.
What is the ortho problem most identified in primary teeth?
Posterior Crossbite
Last dimension to grow in face?
Height
Mandibular movement downward and forward is due to?
Displacement
What sutures are most and least affected by Rapid Palatal Expansion?
A>P
MOST:
Circummaxillary Sutures
-Significant width increases in the intermaxillary, internasal, maxillonasal, frontomaxillary, and frontonasal sutures.
-The greatest increase in width was recorded for the intermaxillary suture
-The midpalatal suture showed the greatest increase in width at the central incisor level
LEAST:
Posterior (zygomatic interface) craniofacial structures.
Frontozygomatic, zygomaticomaxillary, zygomaticotemporal, and pterygomaxillary sutures showed nonsignificant changes.
Most Common Malocclusion?
Class I
The bite is normal, but the upper teeth slightly overlap the lower teeth.
CLASS I MALOCCLUSION THE MESIOBUCCAL CUSP OF THE UPPER FIRST PERMANENT MOLAR OCCLUDES WITH THE MESIOBUCCAL GROOVE OF THE LOWER FIRST MOLAR, BUT LINE OF OCCLUSION IS INCORRECT BECAUSE OF MALPOSED TEETH, ROTATIONS OR OTHER DISCREPANCIES.
What conditions are favorable for serial extractions?
The most favorable morphologic factors for serial extraction include:
- Class 1 malocclusion, a favorable morphogenetic pattern β one that does not change,
- a flush terminal plane or a mesial step relationship of the primary second molars
- minimum overjet and minimum overbite.
- arch length discrepancy by 10mm or more
- Permanent teeth congenitally absent
RPE
2 turns in 7 days = ?
.25mm x 2 x 7 = 3.5mm
Pacifier usage on the Palatal Vault
Infantsβ palatal tissues are highly plastic and readily reflect the influences of sucking habits.
Duration and intensity of pacifier sucking, as well as the size and shape of the pacifier, all are factors that contribute to the extent of the deformation.
When the children were 12 months old, researchers found palatal tissue deformations in 96 percent of the pacifier-using children.
What is a functional shift?
When upper jaw or dental arch is narrow patient needs to slide the jaw to one side in order to fit the teeth together. This shift is called functional shift.
Expansion is required to address this issue.
What malocclusion has the highest chance of asymmetrical growth
Functional shift
What conditions are favorable for serial extractions?
The most favorable morphologic factors for serial extraction include:
- Class 1 malocclusion, a favorable morphogenetic pattern β one that does not change,
- a flush terminal plane or a mesial step relationship of the primary second molars
- minimum overjet and minimum overbite.
- arch length discrepancy by 10mm or more
- Permanent teeth congenitally absent
RPE
2 turns in 7 days = ?
.25mm x 2 x 7 = 3.5mm
Differential growth of jaws and the cephalocaudal gradient growth are characteristic findings during the adolescent growth spurt. These growth patterns normally result in what PROFILE changes in adolescents?
Becomes LESS CONVEX with maturation
Downward And Forward
Lateral Cephalometric Analysis utilize what landmark to most assess sagittal positioning of the MAXILLA?
Point A
Most concave point of anterior maxilla.
What does the cephalometric Y axis suggest?
Direction of MANDIBULAR growth
Angle Formed between the Sella (S) and Gnathion
(GN) line and the FH plane.
59 degrees average
β¬οΈ Increase of Y-Axis is suggestive of greater vertical growth of the mandible.
Angles increases β¬οΈ with CLASS II facial patterns
What is the Molar relationship on the Crossbite side of a Functional Unilateral Posterior Crossbite?
X-Bite side: CLASS II
Non-X bite side: Class 1 or 3
What percentage of Posterior Crossbites in school-age children normally exhibit a Functional Shift of the Mandible as a component of the Crossbite pattern?
More than 90%
> 90% of posterior crossbites in mixed dentition have a Functional Component.
What is the change in Arch Length Dimension of the Mandible by LATE MESIAL SHIFT of the First Permanent Molars π¦·
A DECREASE β¬οΈ of 2-3mm per QUADRANT
4-6mm total arch
How much does the Intercanine Arch Width change in the Mandible between the primary and final permanent dentition?
Intercanine width - The distance between the cusps of the canines
β¬οΈ Increase of MANDIBULAR = 2.4 Mean (0-5mm)
β¬οΈ Increase of MAXILLARY = 3.0 Mean (
0-6.5mm)
What is a common finding in Class II Div II patients?
Excessive Overbite
Retroclined Central Incisors
The maxilla was prognathic in both malocclusions. (I/II)
A Class II skeletal pattern and reduced interincisal angle were common features of Class II/1 malocclusion, while a Class II skeletal pattern, increased interincisal angle, and skeletal deep bite were common features of Class II/2 malocclusion.
The most frequented encountered SKELETAL DYSPLASIA related to MALOCCLUSION is?
Mandibular Retrognathia
A condition in which the lower jaw is set further back than the upper jaw, making it look like a person has a severe overbite.
What facial type is most present in Class II Div II patients
BRADYFACIAL
In Class II, Division 1 patients, with an excess overjet and proclined maxillary incisors.
Of all the Primary molars, which Molar would the LEAST amount of space loss occur if lost early?
MAX1
Loss of Maxillary 1ST Primary Molar AFTER 6 year Molar erupted
Where should a finger spring appliance force be located on an Incisor that is being pushed to correct a lingual Crossbite?
Middle to upper 1/3 of the crown
Growth Modification of the Mandible using a Functional Mandibular Advancement Appliance is directly targeting which of the following structures?
Mandibular Condyle
Which plane of space matures earliest in dentofacial development?
TRANSVERSE (Horizontal)
- Least amount of change of any facial dimension
- Facial Width
- Greatest rate observed between 2-6 years
- Lower face width (Bigonal) 85% complete by the time first molars erupt
What is the first dimension of growth to treat orthodontically?
Transverse (width)
For both the maxilla and mandible, on average, growth in width is completed in advance of that in length, which ceases before growth in the vertical dimension.
The transverse dimensions of the jaws and dental arches do not tend to alter during puberty, as growth in width is largely completed before the growth spurt.
For males and females, growth of the MAXILLA in all dimensions is completed before that of the mandible*
Growth in length usually continues until 14β17 years in girls and 17β19 years in boys, while vertical growth may extend into the late teens in girls and into the twenties in boys.
Primary vs Secondary Bone Grafting.
When?
PRIMARY: when it occurs early in life
SECONDARY: when it is placed in the mixed dentition before or after eruption of the canines
TERTIARY: when it is placed in the permanent dentition
Action of Class II Elastics?
Best for what facial types?
Reciprocal
Brings Mandibular molars forward with only a slight distalization of the Maxillary Molars.
Can also cause elongation of Mandibular molars and Maxillary Incisors.
Good for Brachyfacial and Mesofacial types
What is the sequence for a non-skeletal ortho case in order?
- Level and Aligning
- Correction of Molar Relationship and Space Closure
- Finishing: Root paralleling, Torque of Incisors, Vertical Incisal relationship, Midline discrepancies, Tooth-Size discorepencies.
W Arch vs Quad Arch?
Similarities and Differences
Both effective in Crossbite Correction
Both forces are equivalent
Quad: more flexible, great range of action,
More bulky for reminder if finger habit is an issue.
Facemask / Reverse headgear
When?
Who?
How?
What?
- After 6 year molars and Permanent Incisors have erupted up to the age of 10.
- Used for children with a-p and Vertical maxillary deficiency. NOT for a combination on maxillary and Mandibular problems
- Anchorage is obtained by force on the chin and forehead.
Maxillary teeth should be splinted together as one unit.
Forward force of maxillary teeth by elastics attached from teeth to appliance - Backward displacement of the Mandibular teeth, Forward displacement of the Maxillary teeth occur. (Not forward movement of the Maxilla)
What teeth, order, and timing, are typical for serial extractions?
Extractions in this order:
- Primary Canine
- Primary 1st Molar
- Permanent 1st Premolar
Interval between extractions is 6-15 months
Type of space loss after a Primary Maxillary Second Molar is lost early?
Space loss after premature extraction of second primary molar in THREE weeks time frame.
An increased amount of space loss in the maxillary arch may be due to significant MESIAL ROTATION of the first molars around the PALATAL ROOT.
MESIO-LINGUAL Rotation
Cortical plates anterior to the molar narrow after extraction, preventing the Molar from advancing directly, limiting its movement to rotation
Condyle degeneration results in causing what type of malocclusion?
Bilateral vs Unilateral
Bilateral:
Anterior open bite is a very common finding in patients with TMJ degenerative diseases.
Unilateral:
Posterior open bite associated with unilateral condylar resorption. Associated with mandibular shift to the affected side. The result is an anterior open bite associated with a posterior open bite on the contralateral side, with occlusal contact occurring only on the posterior region of the affected side
RPE indications and rate per day
The main object of RME is to correct maxillary arch narrowness but its effects are not limited to the maxilla as it is associated with 10 bones in the face and head.
Typically .5mm of lateral expansion per day is achieved by instructing the patient to activate the screw 1/4 turn in the morning and 1/4 turn at night.
approximately 1mm per week is the maximum rate at which the tissue of the midpalatal suture can adapt.
The main resistance to midpalatal suture opening is probably not the suture itself, but in the surrounding structures particularly the sphenoid and zygomatic bones.
Anatomically, there is an increase in the width of the nasal cavity immediately following expansion thereby improves in breathing. The nasal cavity width gain averages of 1.9 mm, but can be as wide as 8 to 10 mm.
What would a Chin Cup be used for?
How does it work?
Improves Class III malocclusion through:
- Posterior repositioning of the mandible
- Redirection of mandibular growth backwards and/or downwards.
- Closing of the gonial angle
- Remodelling of the mandible and temporomandibular joint (TMJ)
- Retardation of mandibular growth, and
retroclination of mandibular incisors
Pull directed Below the Condyle results in a downward and backwards growth on Mandible
Pull directed Through Condyle if no Mandible angle change is desired.
Once Mineralization is complete what is not possible?
Interstitial Growth
- Interstitial growth is the LENGTHENING of the bone resulting from the growth of cartilage and its replacement with bone tissue.
- occurs in hyaline cartilage of epiphyseal plate, increases LENGTH of growing bone.
Primary canine interferences result in?
Posterior Crossbite
Equilibrate interference if possible, if not expand Maxilla.
Most common cause of Class III malocclusion?
Maxillary Deficiency
What is the Curve of Wilson?
The curve, viewed from the front, that contacts the buccal and lingual cusps of the molars, being lower in the middle due to the lingual inclination of the long axes of the mandibular molars.
Deepens Posteriorly
What is the curve of Spee?
The curvature of the mandibular occlusal plane beginning at the premolar and following the buccal cusps of the posterior teeth, continuing to the terminal molar.
The pull of the main muscle of mastication, the masseter, is at a perpendicular angle with the curve of Spee to adapt for favorable loading of force on the teeth.
The long axis of each lower tooth is aligned nearly parallel to their individual arch of closure.
It is of importance to orthodontists as it may contribute to an increased overbite. A flat or mild curve of Spee was essential to an ideal occlusion.
What is Synchondrosis?
Where the connecting medium is hyaline cartilage, a cartilaginous joint is termed a synchondrosis.
Sometimes, this is a temporary form of joint called epiphyseal growth plate, where the cartilage is converted into bone before adult life.
They are immovable joints between bones of the cranial base.
Does ortho increase the risk for TMD?
NO
There is no evidence for a cause-effect relationship between orthodontic treatment and temporomandibular disorders, or that such treatment might improve or prevent them.
The Maxilla is formed by?
Intramembranous Ossification
The DIRECT CONVERSION of MESENCHYMAL tissue into bone is called intramembranous ossification. This process occurs primarily in the bones of the SKULL.
What is an unwanted complication of protraction headgear to correct a Class III occlusion?
The upward and forward rotation of the maxilla during protraction is a major unwanted side effect.
Total Face Height markers on Ceph?
Nasion to Menton
N = nasion, the most anterior point of the FRONTONASAL suture in the midsagittal plane
Me = menton, the most inferior point of the outline of the SYMPHASIS in the midsagittal plane
Orthodontic Anchorage
What is it?
What considerations are needed for it?
Resisting movement of a tooth or number of teeth.
-Unplanned or unwanted tooth movement can have dire consequences in a treatment plan, and therefore using anchorage stop a certain tooth movement becomes important.
Multi-rooted, longer-rooted, triangular shaped root teeth usually provide more anchorage than the single-rooted, short-rooted and ovoid rooted teeth.
What are non-radiograph space analysis
Moyerβs
Tanaka Johnson
Ballard and Wylie
What are strictly radiographic space analysis?
Nanceβs
Huckabaβs
Combination of radiographic and prediction charts for space analysis?
Hixon and Oldfather
Staley Kerberos
How does a trans-palatal arch work?
Passive prevention of rotation of the Maxillary first molars, holds them in place
Development of Vertical Height of Maxilla
When analysing the positions of the anterior teeth on the underlying bone and within the face, it is often obvious that the incisors are positioned well forward (regardless of overjet) in longer faces, often with more convex lip profiles. Equally, it is common for the incisors in shorter faces to appear relatively upright (even retroclined), often with more concave lip profiles.
Vertical growth carries the chin downward, while anteroposterior growth carries it forward.
The major sites of bony additions contributing to the facial growth include the facial sutures, maxillary alveolar processes, mandibular condyle and mandibular alveolar processes.
If vertical growth increments at the facial sutures and the maxillary and mandibular alveolar processes exceed the condylar growth, the mandible would rotate backward. However, if growth at the condyle exceeds the total vertical growth at the facial sutures and alveolar processes, the mandible would rotate forward.
These growth changes significantly alter the lower facial height and the position of chin horizontally and vertically.
What is the growth center for the Mandible?
How does it grow?
Condylar head
The primary growth centre of the mandible, grows in upward and backward directions with the resultant downward and forward displacements of the mandible and carries the mandibular dentition away from the vertebral column and cranial base.
What facial type and conditions is most frequent candidate for four bicuspid extractions.
Because of the need to avoid undue opening of the vertical relationship during treatment and to avoid increasing lip protrusion and convexity, extractions of premolar teeth (with or without enhanced vertical and anteroposterior anchorage) may be necessary in DOLICHOFACIAL patients,
For negative discrepancies of more than 10 mm extraction is almost always required, preferably of first premolars because second premolar extraction is not suitable for large discrepancies
Does extraction of four bicuspids affect facial height?
NO change in patientβs facial height with bicuspid extraction.
The Cephalometric measurement that most directly assesses vertical growth is?
FMA were found to be the most reliable indicators
Frankfurt to Mandibular Plane Angle
What are some conditions that are a disadvantage for functional appliances?
Distal and intrusive movement of maxillary molars
Mesial movement of mandibular molars
Retrusion of maxillary incisors,
Protrusion of mandibular incisors
What is the most anterior point of the chin on a Cephalometric Film?
What is this landmark used for?
Pogonion (Pog)
Facial Plane: N-Pog
What percentage of patients have anterior crowding if Baume II
50%
Baume reported two consistent morphologic arch forms of the primary dentition:
Generalized spaces between the teeth were present (type I)
Teeth were proximal contact without spacing
(type II)
Type 1 - 2/3 of kids
Type 2 - 1/3 of Kids
Where is the Basion (Ba) on a Cephalometric radiograph?
Itβs connection to the Nasion (Na) divides what?
Midpoint on the anterior margin of the Foramen Magnum
Line that defines the cranium from the face.
Arch Size Discrepancy results in what?
Posterior Crossbite
What is the average mesial-distal width of the Permanent Incisors?
Maxillary arch:
Central incisors (9.05 mm in males and 8.62 mm in females) Lateral incisors (7.07 mm in males and 6.95 mm in females).
Mandibular Arch:
Central incisors was lesser (5.68 mm in males and 5.55 mm in females) Lateral incisors (6.31 mm in males and 5.98 mm in females)
What does Hilgers Pendulum Appliance used for?
The Pendulum Appliance is used to distalize the molars for the correction of Class II.
It produces a wide swinging arc of force from the midline of the palate to the upper molars producing a pendulum motion of the spring.
A high vaulted palate makes a child more susceptible to what common infection?
Acute Otitis Media
Which maxilla expansion appliance has the highest rate of failure?
Quad Helix
SNA
Normal range?
+/- indications?
Maxilla to Cranium:
82 degrees +/- 3
\+ = Max prognathism - = Max retrognathism
Which tooth is most Important in a Sagittal relationship?
Canine
What is Cephalocaudal Growth?
The cephalocaudal trend, or cephalocaudal gradient of growth, refers to the pattern of changing spatial proportions over time during growth. (Head to body)
By the time of birth the head has decreased to approximately 30% of total body length.
In adults, the head represents approximately 6% of the body length.
T / F
Ossification of the maxilla begins later than the Mandible?
True
T / F
The cranial base grows less during adolescence relative to its final size than does the mandible or maxilla?
True
It completes a large portion of growth prenatally and during infancy and childhood.
T / F
The βcephalocaudal growth gradientβ theory (CCGG) suggests that the maxilla completes its growth before the mandible.
True
However, The timing of cessation of maxillary and mandibular growth may be closer in some individuals than clinicians assume.
T / F
The cranial vault (which encloses the brain) bones are formed by endochondral ossification.
FALSE
The cranial vault (which encloses the brain) bones are formed by INTRAMEMBRONOUS ossification.
The Maxilla and Mandible are formed by what type of bone formation?
Endochondral Formation
Endochondral bone formation can be found in the bones associated with joint movements and some parts of the skull base.
The measurement values for facial thirds; soft tissue glabella to soft tissue subnasal to soft tissue menton, ideally have what ratio?
1:1 ratio
Children with Flush Terminal Plane in their Primary dentition will usually transform into what Class?
Of the sides with a flush terminal plane, FTP, relationship in the deciduous dentition, 56% progressed to a Class I molar relationship and 44% to Class II in the permanent dentition.
The presence of a mesial step in the deciduous dentition indicates a greater probability for a Class I molar relationship and a lesser probability for a Class II molar relationship.
Maxillary Canine Impaction
Buccal vs Lingual
Buccal canine impaction is mostly associated with anterior transverse (dental and skeletal) deficiency and incisor impaction.
Palatal impaction is mostly associated with small or missing lateral incisors, consistent with the guidance theory.
Which appliances are commonly used in ortho to treat Class II malocclusion by displacing the mandible forward?
Herbst and Frankel
What is the most common reason for Class III malocclusion?
Excessive growth of the mandible.
The molar position of these patients is referred to as mesio-occlusion, whereas the anterior relationship shows a negative overjet.
What is the 3 classifications of the Angleβs relationship?
Normal occlusion:
-The mesiobuccal cusp of the upper first molar occludes with the buccal groove of the lower first molar.β¨- The mesial incline of the maxillary canine occludes with the distal incline of the mandibular canine. The distal incline of the maxillary canine occludes with the mesial incline of the mandibular first premolar.
Class II malocclusion:
-The mesiobuccal cusp of the upper first molar occludes anterior to the buccal groove of the lower first molar. β¨-The mesial incline of the maxillary canine occludes ANTERIORLY with the distal incline of the mandibular canine. β¨The distal surface of the mandibular canine is POSTERIOR to the mesial surface of the maxillary canine by at least the width of a premolar.
Class III malocclusion:
- The mesiobuccal cusp of the upper first molar occludes posterior to the buccal groove of the lower first molar.
- Distal surface of the mandibular canines are mesial to the mesial surface of the maxillary canines by at least the width of a premolarβ¨. Mandibular incisors are in complete crossbite.
Flush Terminal Plane usually ends in what classification by what means?
At the time the primary second molars are lost, both the maxillary and mandibular molars tend to shift mesially into the leeway space, but the mandibular molar normally moves mesially more than its maxillary counterpart.
Late Mesial Shift
This differential movement contributes to the normal transition from a flush terminal plane relationship in the mixed dentition to a Class I relationship in the permanent dentition.
A forward protraction face mask result in what?
Anterior displacement of the maxillary complex ( β¬οΈ increase in SNA)
Anterior displacement of upper teeth β‘οΈ
Lingual inclination of lower incisors β¬ οΈ
B ackward-downward rotation of the mandible π (increase in AFAI, SN.GoGn and FMS β¬οΈ)
Decrease in SNB β¬οΈ
Nasal Index
Types?
Nasal Index = Nasal Breadth / Nasal Height x100
Leptorrhine (long and narrow or Caucasian)
Mesorrhine (medium or Asian)
Platyrrhine (broad and flat or African)
SNB
Normal range?
+/- indications?
80 degrees
\+ = Mand prognathism - = Mand retrognathism
Brodie Crossbite (Scissor)
A severe transverse discrepancy, when all buccal cusps of the mandibular molars are telescoped within the lingual cusps of the maxillary molars.
What Ortho Line separates the Cranium from the Face?
Basion - Nasion (BN)
Relative to the cranial base, the Maxilla is translated (moves) in what direction through normal growth patterns?
Down and forward
Functional crossbite occurs because of?
Occlusal Interference
Which is determinant of direction of growth?
FMA
FMA: the angle between the Frankfort horizontal (orbitale β porion) and mandibular plane.
Distal step goes into Class II what %?
100%
Lip Bumpers
Purpose?
Side Effects?
The lip bumper appliance is designed to gain space and make room for your mandibular teeth.
It does this by moving your molars toward the back of your mouth or allowing the front teeth to drift forward.
- Can cause the first molar to tip distally
- Increase in the arch width seen in the intercanine and deciduous intermolar and premolar distances.
- Incisor proclination
Growth modification of the Mandible using a functional Mandibular advancement appliance is directly targeting which of the following structures?
Mandibular Condyle
A negative ANB would indicate what?
CLASS 3
How can it be determined that a patientβs class III malocclusion is dental?
Flaring of mandibular incisors
Appliances for correction of class III malocclusion in growing patients?
Fixed: Class III elastic with skeletal anchorage -Skeletal effect Removable Modified Baltersβ Bionator III -Dental effect Frankel III -Skeletal/dental
Removable: Reverse twin block -Dental effect Eschler/progenic appliance (removable mandible retractor) -Dental effect Double-piece corrector -Dental effect Tandem appliance -Skeletal/dental
Extra-Oral
Chin cap - Skeletal
Face mask - Skeletal
Headgear for mandibular arch - Skeletal/dental
What does chin cup do?
Restricts growth of Mandible
FMA
High values vs Low Values findings
High: Anterior Open Bite
Low: Deep Bite
What needs rectangular versus round wire?
Torque
What is the most forward marker on the chin
Pogonion
The Facial Plane consists of what line?
N-pogonion
Facial Plane and Cranial Base
What is the common point?
NASION
Facial Plane: Nasion-Pogonion
Cranial Base: Nasion-Sella
