First Semester Flashcards
Rank the hierarchy of evidence from strongest to weakest (8 total)
1) Meta-Analysis
2) Systematic review
3) RCT
4) Cohort (prospective)
5) Case control (prospective)
6) Case control (retrospective
7) Case series/ case report
8) Expert opinions
Describe the Moyers space analysis
Utilizes casts and a Boley gauge
Measure the MD width of lower 4 incisors.
Use a chart to predict the MD of the maxillary canine and premolars and mandibular canine and premolars.
Tends to overpredict by 1.7mm
Describe the Hixon mixed dentition analysis
This utilizes casts, PA radiograph of premolars, and boley gauge
Use a long cone to take the PA radiograph of premolars
Measure MD width of one side of the mandibular arch, then the MD width of the premolars.
Use a chart to predict the MD of the canine and premolars for one side at a time
Tends to underpredict by 0.5mm
Describe the Nance mixed dentition analysis
Cast, boley gauge and PA radiograph of canine and premolars.
Measure width of the lower 4 incisors, then the MD width of canine and premolars in radiograph.
Tends to overestimate by 3mm
Describe the Tanaka Johnson mixed dentition space analysis
Utilizes casts and boley gauge.
Measure MD width of lower 4 incisors then divide this value by 2
For the maxilla, add 11
For the mandible, add 10.5
This predicts the MD width of the incisors, canine, and premolars for one side
Tends to overestimate by 1.1mm
What is the purpose of the Bolton Analysis?
To determine if there is a tooth size discrepancy
What is the process for performing a Bolton analysis?
Measure the MD width of each tooth from mandibular first molar to first molar, then the MD width of each tooth in the maxillary arch from first molar to first molar. With this data, you perform an overall analysis and an anterior 6 analysis. In the overall analysis, the ratio of mandibular to maxillary teeth is 91.3 +/- 2. In the anterior 6 analysis only canine to canine is included. The ratio of mandibular to maxillary is 77.2 +/-2
What are the treatment implications of a Bolton discrepancy?
If the overall percentage is greater than 91.3 +/- 2, or anterior 6 percentage greater than 77.2 +/- 2, there is mandibular excess tooth mass.
If the percentages are greater than the normal values, there is mandibular excess (when compared to maxilla)
Bolton’s analysis helps you determine which arch has the tooth size discrepancy, thus aiding in treatment planning. For example, if there is a mandibular excess, IPR of lower arch and/or build up of maxillary teeth are options.
What are the two main points to achieve an esthetic result?
Symmetry and proportion
True or false… the eye is very good at detecting when symmetry is off
True
Describe Kokich’s study regarding symmetry.
The orthodontist’s, general dentist’s, and lay person’s perception of symmetry was compared by distorting 8 different characteristics and seeing at what point the individual would consider it unaesthetic. The variables included were crown length, crown width, incisal plane, lateral incisor gingival height, height between lip and gingiva, crown angulation, gingival embrasure, and midline. A line of reference for the face would be the tip of “Cupid’s bow” of the upper lip, intraorally was the embrasure between the central incisors. In an esthetic patient there would be symmetry between the left and right side of the face
Describe how proportion is important for facial esthetics
People find proportional things esthetically please. A lot of what is considered esthetics follows the golden rule which is 1.618. An example of this would be having a central incisor where the crown length is 1.618 times longer than the crown width or the apperance of the central incisor being 1.618 times wider than the visible lateral incisor. For the face, it is broken down into horizontal thirds and vertical fifths of the face which should all be proportional to one another.
Who believed that the maxillary incisors are key in esthetics in treatment planning?
Sarver
What happens if the maxillary incisors are proclined too much? (regarding esthetics)
It can limit the amount of tooth display, which is unaesthetic
Who believed the lower incisor should lie over the basal bone. If it were achieved, occlusion and esthetics should follow suit.
Tweed
What is the smile arc?
When viewed from a frontal view, the arc of the maxillary teeth should follow the arc of the lower lip
Sarver looked at the smile arc from an oblique view
What are some esthetic changes that occur with age?
Lips thin Nose and chin soft tissue increase Profile flattens MPA flattens Incisor display and gingival display decreases due to increasing length of upper lip Start to develop wrinkles
According to research done by Kokich, how does the perception of esthetics of lay people, dentists, and orthodontists differ?
The orthodontist was the only one to notice a deviation of the midline where it was unethetic. Everyone was unable to detect a difference in the lateral incisor gingival height as being unaesthetic. Overall, the orthodontist had a better perception of when something was off relative to the general dentist and lay person.
Vertical proportions of the face viewed from both frontal and lateral views can be evaluated by splitting the face into thirds with lines running horizontally. Describe the relationship of these thirds.
The superior third borders (superior = hairline, inferior = Eyebrows)
Middle third borders (superior = eyebrows, inferior = junction of nose and upper lip)
Inferior third borders (superior = junction of nose and upper lip, inferior = soft tissue menton)
The inferior third can be further split into additional thirds. The upper one third should approximate the junction of nose and upper lip, to the interlabial junction. The lower two thirds should approximate the interlabial junction to soft-tissue menton.
What are some racial influences in facial esthetics?
African Americans tend to have fuller lips
Fuller lips is considered esthetic in Caucasian’s too, however it is not as naturally common
Who believed that facial esthetics should be evaluated not only in static but a dynamic way?
Sarver
According to Sarver, what is the difference between the static and dynamic esthetic analysis?
The static smile, AKA posed smile, and dynamic smile (AKA Unposed/spontaneous/animated smile).
He liked to videotape his patients for their dynamic smile. Also he liked to look at different angles. You can evaluate not just from a frontal view but from an oblique view. From the frontal view, there should be at least 75% of incisors display and there should be some degree of buccal corridors. From the oblique view, the maxillary incisors should follow the lower lip
What diagnostic information does the Wits analysis provide?
The AP relationship of the mandible relative to the maxilla. It is a linear measurement (not angular)
How is the Wits analysis measured?
Draw a line through functional occlusal plane (cusp tips of first molar to first premolar)
Draw a Line perpendicular from A point to functional occlusal plane.
Draw a line perpendicular from B point to functional occlusal plane
Measure the distance between the lines perpendicular to occlusal plane
How does the Wits analysis compare to ANB?
Wits is a linear measurement whereas ANB is an angular measurement
How do you draw the functional occlusal plane when performing the Wits analysis?
Connect point from cusp tips of first molar to first premolar
Is the Wits analysis a good replacement for ANB? Why or why not?
It is not a good replacement, but can be used as a supplement to ANB. It may be difficult to accurately determine where the functional occlusal plane is due to superimpositioning in the ceph or just difficulty finding the points in general.
Steiner chevrons (AKA Steiner Sticks) provide a summary of ceph analysis in a simplified view. Describe the 5 measurements included in the chevrons.
ANB = most superior placed value
U1-NA (maxillary incisor angulation) = Upper left value
U1-NA (mm) = upper right value (measures protrusion of upper incisor)
L1-NB (mandibular incisor angulation) = lower left value
L1-NB (mm) = lower right value (measures AP position of lower incisors)
According to Steiner’s chevrons, what are the ideal values for ANB, U1-NA, U1-N perpendicular to FH, L1-NPo, and Po-NB?
ANB = 2 degrees U1-NA = 22 degrees U1-NA = 4mm L1-NB = 25 degrees L1-NB = 4mm
Big picture, what do the Steiner chevrons represent? How can you use this info to aid you in diagnosing and treatment planning your patients?
The possible compensation/camouflage that can be done. It is a dental compensation for a skeletal problem. It shows the limit of how teeth can be moved in patients with varying skeletal problems based on what the ANB is
What do mixed dentition analyses do and what is their purpose?
The purpose of a mixed dentition analysis is to help tell you if you will have enough space available for the developing permanent canines and premolars. This will help you determine treatment objectives. For example, how much additional space would be needed for permanent dentition to erupt, and if so, how much
Name some additional aging effects
Decrease turgor of soft tissue Skin becomes less resilient Philtrum height greater than commisure height, looking like a frown Increased lower incisor display Increase depth of nasolabial fold Crows feet around eyes The M of upper lip flattening
What orthodontic concepts are important to help minimize the effects of premature aging
Better to err on side of too gummy smile in young patient because lower lip will lengthen with age
Don’t want to procline incisors too much because it will decrease incisors and gingival display
If pt has thin lips and flat profile, probably not a good idea to extract
Consonant smile arch where incisal edges follow lower lip is better than maxillary incisal edges lined up at expense of non-consonant smile with lower lip (reverse smile arch ages the pt)
According to the study done by Kokich, what are the most noticeable things to lay people?
Incisal plane
Incisor angulation
Crown length
According to Kokich, off-centered midline were detectable at __mm by orthodontists, whereas it was undetectable in dentists nd laypeople.
4mm
True or false… Wits doesn’t tell you what the jaw problem is coming from , just simply that there is a discrepancy between the two arches. ANB however, relates the descrpancy to the cranial base.
True
Wha are the norms for the Wits analysis for males and females?
Males = -1 Females = 0
(If the number is more negative it means that the pt is more class 3 and if it is more positive it means they are more class 2)
What are the pros and cons of using ANB over Wits?
ANB relates discrepancy to cranial base
ANB can be inaccurate if headposition is inaccurate
If nasion is placed incorrectly you will have inaccurate ANB
Rotation of the occlusal plane/jaws can lead to inaccuracies in ANB measurement
What are the pros and cons of Wits over ANB?
Don’t have to accurately find nasion. Eliminates clockwise/counterclockwise rotation of occlusal plane affecting measurement.
If the occlusal pane is placed incorrectly it can cause inaccuracies
Difficult to determine correct occlusal plane
Which type of dental trauma is most likely to lead to pulpal necrosis?
Intrusion
If a pt presents to your office with a luxation injury that requires splinting of the injured tooth, is it better to use rigid wire or flexible wire to splint the teeth together? Why?
Flexible, a stiff wire can result in ankylosis
Out of the mixed dentition analyses which is the most accurate and which is the least accurate? Do they tend to overpredict or underpredict?
Hixon and Oldfather is the most accurate, it tends to under predict by about 0.5mm
The Nance analysis is the least accurate, it tends to overpredict by 3mm
Which mixed dentition analysis uses radiographs AND a prediction chart?
Hixon and Oldfather
Which mixed dentition analysis uses radiographs WITHOUT a prediction chart?
Nance analysis
Which mixed dentition analyses do not use radiographs at all? How accurate are they both?
Johnston-Tanaka analysis
Moyers analysis
Both are about 75% accurate, but usually results in overprediction
What are 4 possible causes to a gummy smile?
Vertical maxillary excess
Upright maxillary incisor angulation
Excessive smile animation
Short philtrum height
Incisor display at rest in adolescents should be at least ___mm. Should you intrude if there is excess (4-5mm)?
2mm
No. It would prematurely age the patient
Typically is it better to err on the side of too much or too little buccal corridor?
Too little (more full smile)
However, too full a smile by obliterating the buccal corridors completely can look fake
What are the two major concepts from Sarver and how are they different form previous concepts?
Concerned with the upper incisor and soft tissue profile when diagnosing and treatment planning cases. Concerned with the effects of aging on the soft tissues of the face
Concept is diffferent in that soft tissue is what ultimately directs treatment directions and decision-making, NOT the cephalometric numbers (Angle focused on occlusion first thinking esthetics would follow, not Sarver).
Meeting ABO criteria does not necessarily mean an esthetic smile
Expanding dental arches to increase hard tissue support for the lips and cheeks or enlarging the facial skeletal surgically to increase hard tissue support is usually more esthetic
3/4 view of face, video recordings, and resting vs dynamic soft tissue relationship can be of value in diagnosis
UPPER (not lower, according to Tweed) incisors are key to esthetics in orthodontic treatment planning.
Time (aging) is an important dimension in determining esthetics.
Should identify and quantify POSITIVE aspects of pts esthetics so they are not comprimised in trying to fix wht is wrong
What are the three types of smiles Sarver evaluated in his diagnostic video recordings?
Commisure smile (Mona Lisa smile, corners turn up)
Cuspid smile (upper lips move)
Complex smile (upper and lower lips move)
In an esthetically pleasing face, the philtrum should be no more than ___ [shorter/longer] than the commissure height.
2-3mm shorter
In an ideal smile, how much maxillary incisor should show with an animated smile?
100% plus some gingival display
Does vertical soft tissue growth occur to a greater extent in males or females?
Males
Is it better to err on the side of more or less chin projection in an orthognathic case? Why?
Less chin projection because the chin soft tissue will continue to grow with age. Short term, a prominent chin would be ok, but it would look bad as the pt ages
Define the soft tissue paradigm
Treatment planning is based on static and dynamic soft tissue relationships of the face, lips, and periodontium
What are the major concepts from Kokich’s article in regard to perception of variation?
Orthodontists notice deviations sooner than lay people and GPs
We need to treat to the lay persons perception (what they notice) and not necessarily what we notice
Dental and tissue discrepancies are potentially more unaesthetic when they are asymmetric rather than symmetric
According to the article by Kokich, when should you treat?
To the lay person’s perception:
When midline is over 4mm off Lateral width less than 4mm Crown angulation off by 2mm Cant at 3mm Gingival embrasures at 3mm And gummy smile at 4mm or more
True or false.. forward or backward position of the pt’s nasion can change the ANB reading to insinuate a discrepancy that is more or less severe than in reality
True
What is natural head position?
Standardized and reproducible
Important for using extracranial verticals
Critical in lateral cephs, but even more so in PA cephs
What happens if a pt’s head is turned too far down when taking a lateral ceph (not in natural head position)?
They appear more class 2
How is natural head position found?
Tell pt to sit upright and look straight ahead at a distant point at eye level
Use a short mirror
Place patients in natural head position with the ear rods exactly concentric (however, this wil only lead to a good head position if the external meati are exactly symmetric)
How is natural head position compared to Frankfurt horizontal?
FH is defined as a line from porion to orbitale
FH is good for studying skulls, but not natural head position
If FH is tilted up or down, discrepancies in facial typing cephs and phots disappear?
The profile with the Eastman normal was rated as the most attractive. What is the Eastman normal?
LAFH/TAFH = 55%
Attractiveness scores reduced as the lower face proportions increased from the normal value
Images with reduced lower face proportions generally scored higher (more attractive) than those with increased lower face proportions
Images with a reduced lower face proportion were less likely to be judges as needing treatment than corresponding images with an increased lower face proportion
Older subjects were less critical when rating the attractiveness of vertical skeletal discrepancy
What are two factors that contribute to the fact that incisor display diminishes with age?
inferior migration of the surrounding soft tissue
attrition and wear of the anterior teeth
Maximum display of incisors occurs at age __ for females and age ___ for males
11
12
maximum lip incompetency also occurs at these ages
Name five things that could contribute to a gummy smile
vertical maxillary excess
upright maxillary incisor angulation
excessive smile animation
short philtrum height
delayed passive eruption
Desirable incisor display at rest is ___, but if there is excess of 4-5mm (in a young patient) you don’t want to intrude because….
2mm
it would prematurely age the patient
Philtrum height should be no more than ___ shorter than commissure height
2-3mm
True or false… clinical appearance of anterior teeth almost always should override traditional cephalometric measurements
true
Why do the chevrons (Steiner sticks) not include ANB values over 8 or under -1?
They are not good candidates for camouflage and surgery should be considered
True or false.. asymmetric alterations of the dentition make the teeth less attractive to only dental professionals but not lay people
false
In regards to examining the ratio of LAFH/TAFH, older subjects were [more/less] critical when rating the attractiveness of vertical skeletal discrepancies
less
In regards to what is considered esthetic in African American populations, in more recent times, lips are [thinner/fuller] and more [anteriorly/posteriorly] positioned, and the nasolabial angle was more [acute/obtuse] than in previous decades.
fuller
anteriorly
acute
What was the primary reference plane used by Steiner? Why?
SN (anterior cranial base)
The advantages of using SN vs FH: S and N are moved very little whenever the head deviates from natural head position. sometimes it is hard to locate orbitale and porion (S and N are easier)
What were the primary reference planes used by Downs?
FH and facial axis (AKA Y axis: line drawn from S-Gn)
Describe the Facial axis (Y axis).
Line drawn from S-Gn
A larger angle of FH-Y axis is seen in class 2 patients and a smaller angle in class 3 patients. the Y axis is an indication of downward, forward, or rearward position of the chin in relation to the upper face.
What was the primary reference plane(s) used by Tweed?
Mandibular plane
FH
used the MP-FH vs MP-SN (Steiner).
related MP-FH-lower incisor angle*
What were the primary reference planes used by Ricketts?
FH, and facial axis (Pt-Gn line and Ba-N; lesser angles represent retroclined chins - class 2)
What is Ricketts esthetic line?
extends from soft tissue tip of nose (En) to the soft tissue chin point (Dt)
upper lip should be 2-4mm posterior to E line for maximum esthetics
According to Ricketts, what was referred to as the dental plane?
A-Po line
The goal of cephalometric analysis is to evaluate the vertical and AP horizontal relationships of the 5 major functional components of the face. what are these 5 components?
cranium/cranial base
skeletal maxilla
skeletal mandible
maxillary dentition/alveolar process
mandibular denttion/alveolar process
What are the main purposes of lateral cephs?
diagnosis and treatment planning
monitoring treatment changes and final outcome
monitor growth
What are some of the cons of cephalometric?
ignores facial esthetics
not absolute (only use as a guideline)
cephs are compared to norms, but “beauty is not the norm”.
2D image of 3D object
anatomic landmarks not consistently identifiable
distortions are possible
What does VTO stand for? what is the purpose of VTO?
Visual treatment objective
useful for treatment planning
used to help get a “feel” of a case by predicting outcomes
better than static synthesis of a tracing in time
Regarding a bolton discrepancy, results less than ___mm are rarely considered to be clinically significant
1.5mm
What is the ideal Bolton ratio (overall ratio)?
91.3
What is the ideal Bolton anterior 6 ratio?
77.2
The ideal Bolton ratios assumes what two things?
proper angulation of incisors
normal thickness on the labiolingual surface of anterior teeth
A study in 1996 found that __% of ortho patients have significant anterior tooth-size discrepancy. another study found __%. thus it is important for clinicians to routinely include a tooth-size analysis in the initial case work up
30%
23%
Overprediction of the mixed dentition space analysis (over predicting size of permanent teeth) can result in what consequence? Which space analysis is the only one that does not over predict?
unnecessary extractions
All methods of mixed dentition space analysis tend to over predict, except for the hixon-oldfather equation
Clinically significant measurement errors can occur when the Bolton tooth-size analysis is performed on casts that have at least __mm of crowding.
3mm
The size and frequency of these errors evidenced considerable inter-individual variation
Which is more accurate in performing Bolton analysis on stone models, Boley gauge or needle-point dividers?
Boley gauge
In children, diastemas larger than __mm are at risk of not closing with normal development
2mm
True or false… upright position of anterior teeth (root facially) can increase spacing in maxillary arch.
true
What are seven keys for on-time finishing?
- appropriate diagnosis and treatment planning (in most cases, treatment should be delayed until eruption of second molars)
- efficient appliances (reduce need for pt compliance)
- realistic treatment time estimates (err on side of overestimation)
- progress reviews: give frequent updates to parents and pts
- pt incentives
- practice management software to help you monitor pts
- make it a priority to finish on time
What information does the facial angle provide? what is the average value?
tells you about protrusion/retrusion of the Mn
average = 87.8 (a prominent chin increases this angle)
Tweed believed that the incisor MN plane angle should be __ degrees for stable results
90 degrees
What is the ideal ANB value?
2 degrees
Calculations have indicated that tipping lower incisor forward 3 degrees results in a total dental arch length increase of ___mm
2.5mm
Natural head position is a standardized a reproducible orientation of the head in space when one is focusing on a distant point at eye level. to achieve uniformity in craniometric research, the ___ was agreed upon.
Frankfort Horizontal
___ developed VTO
Ricketts
According to Ricketts in 1961, SN change has been found useful because the maxilla seems to grow forward at almost an identical rate with ___
nasion
True or false.. the MPA increases with age
false. it decreases (flattens) with age due to differential jaw growth
What is the purpose of the Wits appraisal?
to identify instances in which the ANB reading does not accurately reflect the extent of AP jaw dysplasia.
What are some factors that can make the ANB value inaccurate?
rotation of the jaws
Inclination of palatal plane
abnormal vertical facial dimension
abnormal nasion position
AP positioning of the jaws
ANB reading is reliable indication of AP jaw discrepancy if patients have a ___ greater than 37 or less than 27 degrees.
MPA
What are two factors that affect the Wits reading?
occlusal plane
vertical alveolar dimension
[Wits appraisal/ANB angle] changes significantly with age whereas the other does not
ANB angle
Vohies and Adams (1951) developed a polygon that expresses a large group of ___ graphically. Describe how it works.
cephalometric readings
They used the max and min ranges of each Down’s measurements and plotted these figures on both sides of the vertical mean. All the reading that would indicate a class 2 trend on are on the left and class 3 on the right. The skeletal polygon is on the top and dental on the bottom. Solid lines represent extremes of the range
According to Downs, the Mandibular plane is tangent to the ___ and the ___
gonial angle
lower point of the symphysis (menton)
In regards to the Y axis, class 2 are more likely to have a [smaller/larger] angle, whereas class 3 a [smaller/larger] angle.
larger
smaller
Why did Steiner prefer to use the anterior cranial base (SN) as the line of reference to which the jaws would be related?
the advantage of using these two midline points is that they are moved only a minimal amount whenever the head deviates from the true profile position or is rotated
In Steiner’s S-line, Lips in a well-balanced face should touch a line extending from __ to __
the soft tissue contour of the chin
the middle of an S formed by the lower border of the nose
Tweed’s main treatment goal was ___. He believed that ___ philosophy would result in dentitions that would end up collapsing. He believed there was too much tooth mass for the ___. He stated that the mandibular incisors must always be positioned…
Stability
non-extraction
Basal bone
in an upright position on the alveolar process and over medullary bone. 90 degrees +/- 5 degrees
True or false… the philtrum lengthens at a greater rate than the commissure over time
true. Thus, this leads to flattening of the upper lip vermillion border (Sarver)
According to Dickens, Sarver, and Profit, what are the causes of a gummy smile?
VME upright maxillary incisors excessive smile animation Short Philtrum height altered passive eruption
What are the three basic requirements for assessing dento-facial esthetics in orthodontics? (according to Sarver in the article “re-emergence of the esthetic paradigm”)
- a dynamic and static 3D evaluation of face derived primarily from clinical examination (including 3/4 view)
- a determination of lip-tooth relationship and anterior tooth display at rest and during facial animation (frontal and 3/4 view more important than profile view)
- an analysis of dental and skeletal volume of the face as it affects the soft tissue.
True or false… females show less maxillary incisors and more mandibular incisors at rest and on smile than males.
false… males show less maxillary incisors and more mandibular incisors at rest and on smile than females
The lower third of the face is the most important third for orthodontists because its the area we have the most control over. in the lower third, the upper lip should make up the upper __ and the lower lip and chin should make up the lower __
1/3
2/3
Does vertical soft-tissue growth occur to a greater extent in males or females?
males
Why is the 3/4 view an important assessment?
it is the facial angle that is observed naturally the most
the nasal form is best evaluated in oblique view because the nasal dorsum can be seen in more 3D
the lower face is better evaluated for throat form and chin-neck continuity
can observe the smile arc more posteriorly
In the female face, increased prominence of the upper or lower lip is considered more esthetic
upper lip over the lower lip
In the Kokich study, orthodontists noticed an off-centered midline at ___ whereas GPs and lay people noticed at ___
4mm
not even at 4mm
In the Kokich study, orthodontists and dentists noticed an off incisal plane at ___mm where as lay people noticed at ___mm
1mm
3mm
According to the Kokich study, what was the most easily detected discrepancy by orthodontists and general dentists?
incisal plane asymmetry
However, lay people didn’t notice until it was off by 3mm
The incisal plane is supposed to be parallel to the ___
inter pupillary line
Why are midline discrepancies often unnoticed?
if the incisal plane is ok. …meaning the contact between the two central incisors is perpendicular to the incisal plane which is parallel to interpupillary line.
What is the best reference for the facial midline in most individuals?
tip of Cupid’s bow (top middle of upper lip)
What is the best reference for the dental midline?
papilla between centrals
Should you correct a midline that is off centered by less than 4mm if incisal plane is ok, and posterior occlusion is ok?
no. Research does not support correcting midlines less than 4mm for purely esthetic purposes
Should you treat the incisal plane if the mediolateral inclination of incisors deviates by 1-2mm?
yes. this is far more noticeable than a midline deviation. Treat by uprighting the roots to be perpendicular with interpupillar line (do this at the expense of “off” incisal edges if necessary, you may need enameloplasty or restorative to fix incisal edges)
What are the three ways to treat incisal plane asymmetry? (depending on diagnosis of course)
surgery
ortho
restorative
How do you determine if an asymmetric incisal plane needs surgery?
Compare the incisal plane with posterior occlusal plane. if they BOTH deviate from inter pupillary line, problem is unilateral asymmetric growth and needs to be corrected by surgery. If only anterior plane is off but posterior is on with inter pupillary line, finger habit or attrition could have altered the incisal plane (needs ortho or restorative to fix)
What are possible treatments for a gummy smile?
maxillofacial surgery periodontal surgery orthodontic intrusion (possibly with restorative)
How do you determine if a patient who displays excessive gingiva anterior and posterior, with normal sized crowns, is a candidate for maxillofacial surgery?
see how much maxillary teeth show at REST. if 3mm or less, do NOT refer for surgery. in this case, they have a hyper mobile lip (not many good treatment options)
If they display well over 3mm of tooth at rest, they have VME and could be referred for surgery
If patient displays excessive gingiva anterior only, but has short clinical crowns, what should you look at next to determine diagnosis and treatment options?
depth of sulcus
if deep, pt has altered passive eruption. in this case gingivectomy can be performed (assuming enough keratinized attached gingiva)
If sulcus is normal (~1mm) pt has short anatomical crowns. either perio surgery to apically position gingival margins (however this exposes the roots and shortens crown-root ratio), or orthodontic intrusion with restorations to increase crown length
What is the fourth dimension orthodontists now consider in diagnosis and treatment planning?
time
Define commissure smile
AKA Mona Lisa smile
corners of mouth turn upward due to pull of zygomaticus major muscles
Define cuspid smile
entire upper lip is elevated without corners of the mouth turning upward
define complex smile
upper lip moves up while the lower lip moves inferiorly
According to Spear and Ackerman (2003) should we treat the social smile or the enjoyment smile?
social smile because it is repeatable
Ackerman developed a ratio called the smile index. explain what this is
it describes the area framed by the vermillion borders of the lips during the social smile.
The smile index is determined by dividing the intercommissure width by the interlabial gap during smile
Does the smile index involve the social smile or the enjoyment smile?
social smile
The smile index is determined by dividing the ___ by the ___ during smile
intercommissure width
interlabial gap
although some argue that 100% + of maxillary incisors is esthetic during smile, tooth display less than ___ during smile is considered inadequate
75%
How is buccal corridor measured?
Measured from mesial line angle of maxillary first premolar to interior portion of the commissure
The transverse smile dimension is a function of both __ and __ of the maxillary and mandibular arches
arch width
AP position (bringing the wider portion of the arches forward fills up negative space)
True or false.. the broader the arch form the more likely the smile arch will flatten
true
From which dimension is overjet and incisor angulation best visualized
sagittal (profile view)
The transverse characteristics include what three things?
arch form
buccal corridor
transverse cant of occlusal plane
in the study “the influence of lower face vertical proportion of facial attractiveness” in 2005, images with [increased/decreased] lower face proportions were more likely to seek treatment than the corresponding images with [increased/decreased] lower face proportions
increased
decreased
True or false… the study “correlations between cephalometric and facial photographic measurements of craniofacial form” in 2007 demonstrated that the ceph is the method of choice for patient care, however photographs might be better for large-scale epidemiological studies
true
photographic estimates of vertical facial height are best representative of cephs because landmarks such as N and Me are not influenced by excessive soft tissue in these areas (less soft tissue, the better the photograph is at estimating the bony landmark)
Is it Christmas break yet?!?
ALLLLMOST!!! xD
Which is typically easier to read/more accurate for determining stage of growth, hand/wrist radiograph or cervical vertebrae in ceph?
Hand-wrist radiograph is easier to read and tends to be more accurate, however it is less convenient than a ceph. So, first take a ceph, if identifying the stage of growth is critical and you’re not sure about the ceph reading, take a hand-wrist
Do Invisalign algorithms for IPR then to round up or round down?
round up. So be conservative with the IPR recommendations with Invisalign
Which arch, mandibular or maxillary arch is most likely to be in excess (Bolton discrepancy)?
mandibular
What would happen if you proline the lower incisors without leveling the arch?
you end up pushing the mandible down and back (open the bite)
Which type of pt, dolicho, meso, or brachy tends to take longer to level and align?
brachy and normal
dolicho will move quickly. but be careful, they can come back with a reverse curve of speed and an anterior open bite.
Why should you keep torque on the upper incisors as you are retracting them?
If you don’t, the incisors can become too upright by flaring the roots facially (called “rabbitting back incisors) and this can actually open space in the maxillary arch as functional overjet is lost.
The MBT prescription puts ___ degrees of ___ torque in the maxillary incisors even though not that much torque is needed. why?
17
positive
wire/slot slop (finishing arch wire in MBT is 19x25SS)
What are Dr. Minick’s 3Cs tat contribute to crowding?
crowding
curve of speed
class correction
What does Dr. Minick recommend to treatment plan borderline extraction cases?
If you are going to do a “therapeutic diagnosis” give yourself 6-9 months to line up the teeth. You should be able to make the decision to extract or not within that timeframe. Plan a consult 6 months from start to discuss necessity of extractions or not
What are two undesirable esthetic side effects of arch expansion when viewed from the frontal dimension?
Buccal corridor can be obliterated
smile arc may be flattened
What are three ways the palatal plane can be canted anteroposterioly to cause an anterior open bite?
downward cant of posterior maxilla
upward cant of anterior maxilla
variations of both
According to Sarver, what is the most accepted attribute of an esthetically please smile?
smile arc
conventional prescriptions call for 0.5mm difference between central to lateral slots. Sarver/Ackerman recommences 1-1.5mm difference
According to the Kokich article, when did orthodontists, dentists, and lay people discern crown length discrepancy was considered unesthetic?
Orthodontist: 1mm
GP: 1.5mm
Lay people: 2mm
According to the Kokich article, when did orthodontists, dentists, and lay people discern crown width discrepancy was considered unesthetic?
Orthodontists: 3mm
GP: 3mm
Lay people: 4mm
According to the Kokich article, when did orthodontists, dentists, and lay people discern crown angulation (mediolaterally) discrepancy was considered unesthetic?
Orthodontists: 2mm
GP: 2mm
Lay people: 2mm
According to the Kokich article, when did orthodontists, dentists, and lay people discern a midline discrepancy was considered unesthetic?
orthodontists: at 4mm
GP: not even at 4mm
Lay people: not even at 4mm
According to the Kokich article, when did orthodontists, dentists, and lay people discern an open gingival embrasure discrepancy was considered unesthetic?
Orthodontist: 2mm
general dentists: 3mm
Lay people: 3mm
According to the Kokich article, when did orthodontists, dentists, and lay people discern a gingival margin discrepancy was considered unesthetic?
Ortho, GP, Lay people: not even at 4mm
According to the Kokich article, when did orthodontists, dentists, and lay people discern an incisal plane discrepancy was considered unesthetic?
orthodontist: 1mm
GP: 1mm
Lay people: 3mm
According to the Kokich article, when did orthodontists, dentists, and lay people discern a gingiva-to-lip discrepancy was considered unesthetic?
orthodontist: 2mm
GP: 4mm
Lay people: 4mm
According to the Kokich article, what was considered the most noticeable esthetic feature by orthodontists?
tooth position
According to the Kokich article, what was considered the most noticeable esthetic feature by general dentists?
tooth color (orthodontists also ranked tooth color high)
According to the Kokich article, what was considered the most noticeable esthetic feature by lay people?
mouth expression and lip shape (out of dental and perioral features)
lay people rated hairstyle as most esthetic feature overall
all three groups ranked eyebrow expression last
What did the kokich article find about obsessive-compulsive personality tendency in discerning esthetics?
no significant findings show that OC personalities are elated to perceptions in esthetics
In regards to photography accurately estimating landmarks, which points are the most reliable?
estimates on vertical facial height
N and Me (not as heavily influenced by excessive soft tissue)
How is philtrum height measured?
from subspinale to most inferior portion of UL on vermillion tip beneath philtral columns
How is commissure height measured?
line constructed from alar bases through subspinale
Measure from commissures perpendicular to the line described above
What is the normal vertical height range of U1s in males and females?
9-12mm
- 6mm males
- 6mm females
What is one procedure described by Sarver that can be used to immobilize the upper lip in hyper mobile lip cases with gummy smile?
V-Y cheiloplasty to lengthen UL
According to DeSmit and Dermaut (1984), vertical profile characteristics were [more/less] important than AP characteristics in facial esthetics
more
However a different study done by Johnston (2005) found that over 70% of subjects with AP discrepancies over 3 standard deviations from the mean would seek treatment. (more seek treatment for AP than vertical discepacancies)
Conflicting Data
Which teeth are at most risk for endo issues?
teeth with mature apices and hx of trauma (rapid movements decrease blood supply)
True or false… ortho treated teeth have decreased pulp sizes than non-ortho treated teeth
true
what is the success rate of RCT? does it depend most on the RCT or the restoration?
90%
restoration
Can you move a RCT treated tooth?
Yessir!
ortho forces involve the PDL, so RCT teeth move just as readily and to the same distance as teeth with vital. pulp
Should you orthodontically move teeth that need RCT?
controversial
some say you can place calcium hydroxide until end of ortho treatment.
some say you can complete during treatment
Can you move a tooth with apex-genesis
Yup!
Can you move a tooth with specification?
Yeah totally
ortho can be initiated before completion of calcified barrier. if MTA application you can start immediately
some advocate to wait 6 months in presence of PARL
Can you move a tooth with REP (regenerative Endodontics procedure)?
YASSS
it will respond similarly to vital teeth
Can you move a tooth with internal resorption?
OH YEAH!
although some evidence suggests you would get a better outcome if pausing 1 year before ortho treatment
Can you move a tooth with external cervical resorption?
you betcha!
however, some evidences suggests you would Get a better outcome when pausing 1 year before ortho treatment
true or false.. orthodontic forces are considered controlled trauma
true
True or false.. odontoclasts and osteoblasts readily bind to pre-dentine/pre-cementum
false
What is the overall incidence of external inflammatory resorption in ortho treated teeth?
28.8%
If there is no bacterial involvement in external inflammatory resorption, it will [continue/stop] when orthodontic forces stop. If bacterial involvement, what should be done?
stop
RCT and calcium hydroxide to stop the resorption
can you move a tooth with external inflammatory resorption?
fo shizzle my nizzle
however there is a chance you’d induce more resorption. better outcome when 1 year pause before ortho treatment
Can you move a tooth that had endo surgery?
hell yeah
there is a lack of literature though. be careful because buccal bone could be compromised (take a CBCT)
If replantation, wait 3-9 months
__% of children aged 6-18 experienced dental trauma in 2017. __% of these cases were avulsion. [females/males] tend to have more dental injuries
11%
0.5%-16%
males
Which teeth are the most traumatized teeth?
maxillary centrals
If a patient has had previous dental trauma, they have a __x more chance of getting a new injury
5times
Does a mouth guard protect against dental trauma sufficiently?
low level of evidence and lack of agreement in literature
best appliance is a well-fitted appliance. ortho-modified version should not lock teeth in position, should have a smooth, flat occlusal surface, protect soft tissues and ortho appliances
Historically, it was thought that overjet >4mm increased susceptibility of trauma. recent studies show…
they have the same prevalence of trauma than regular population, so there is no need for early ortho treatment
What type of splint should you use to stabilize a traumatized tooth?
flexible, short-term splint (depends on extent of occlusal trauma (2-4 weeks))
periodontal and pulp healing better with slight mobility and function of the tooth
When should the orthodontist reposition a traumatized tooth that was intruded?
wait 4 weeks after trauma (if no spontaneous re-eruption occurs)
Mature teeth, less than 3mm after 4 weeks
In order to move forward with comprehensive ortho, you should wait __ months after minor injuries, ___ months for moderate to major injures, and ___ for root fractures.
3 months
6 months to 1 year
1-2 years
If vertical growth of posterior maxilla exceeds anterior maxilla, it could affect the relationship of occlusal plane and smile arc, how can you remedy this situation?
use HPHG to keep maxillary posteriors superior to incisors
What is the “orthodontic dilemma” regarding esthetics?
esthetics are paramount to tx planning orthodontic and orthognathic cases, but rigid rules cannot be applied to this process. … so we optimize dent-facial esthetics with flexible guidelines
What are Sarver’s guidelines of esthetics
- 3D clinical eval.
- lip/tooth relationship (Upper incisors key)
- dental/skeletal volume
Are there greater dimensions of philtrum and commissure height in males or females?
males
amount of incisor display at rest, gingival display on smile, percent incisor display on smile, and lip separation all decreased after adolescence in both males and females, particularly beyond the age of __
20
True or false… when a patient ages, their ability to elevate the lip on smile is lost.
false.. although the lips sag downward at rest, the ability to elevate the lip on smile is retained
true or false.. when the occlusal plane is used to evaluate the relationship between the upper and lower dentures (Wits), clockwise/counterclockwise rotation becomes irrelevant
true
because the reference plane common to both dentures is the occlusal plane
Can you orthodontically move teeth into a periodontal defect (has not been treated with GTR)?
yes, as long as the inflammation is under control
If a periodontal defect has been treated with GTR, can you orthodontically move a tooth into that area?
yes, but you must wait a minimum of 8-12 weeks to move into the graft to prevent resorption of the graft.
Why does a thick biotype respond better to buccal tooth movement than thin biotype?
thick biotype reacts more favorably to buccal tooth movement because it is made up of 50% bundle bone. Thick biotype reacts to insult by increased pocket depth, not necessarily recession.
Before starting ortho, when should you refer to perio for a graft of thin marginal tissues?
if less than 2mm of keratinized gingiva (one of which must be attached gingiva)
where is keratinized tissue width the smallest?
mandibular canine and premolar region
fenestrations (windows) are more common in the [mandible/maxilla] whereas dehiscences (full collapse) are more common in the [mandible/maxilla]
maxilla
mandible
Which teeth, anterior or posterior, respond better to root-buccal tooth movement?
posterior
True or false… moving teeth back into the alveolar envelope after bone damage has occurred WILL allow for creeping attachment and better result with gingival graft
true.
What is the difference between Down’s Y-axis (growth axis) and Rickett’s Facial axis?
Down’s Y axis (AKA growth axis)= Angle between FH and S-Gn. The y axis is an indication of downward, forward, or rearward position of the chin in relation to the upper face.
Rickett’s Facial axis = Pt-Gn Line and Ba-N. Average = 90 degrees. Lesser angles = more class retroclined chins (class 2)
What is the facial plane (Ricketts)? What is the facial angle?
Facial plane = N-Pog
Facial angle = angle between N-Pog and FH. Helps determine horizontal chin position
How does the Ricketts analysis evaluate protrusion of the lower incisors?
L1 - A-Pog (A-Pog = dental plane) in mm
L1 should be 1mm anterior to dental plane
How does the Ricketts analysis evaluate the proclination of the lower incisors?
L1 - A-PO angle (note that A-PO is different than A-Pog!!!)
average is 28 degrees
What is Rickett’s mandibular plane? MPA?
Mandibular plane = Go-Gn
MPA = Go-Gn and FH average = 26
what is Rickett’s convexity at point A?
measure from point A to the facial plane (N-Pog)
clinical norm is 2mm
Explain Rickett’s upper molar to PtV measurement
Distance from pterygoid vertical (back of maxilla) to distal of the upper molar
Should = pts age +3mm
Assists in determining whether the malocclusion is due to upper or lower molar position and identifying if extractions are necessary
Describe Rickett’s condylar axis
DC to Xi point
used to describer morphologic features of the mandible
DC = point in the center of the condyle neck along the Ba-N plane
Xi = geometric to FH and pterygoid vertical planes
Describe Rickett’s corpus axis
Xi to PM
used to describe the morphology of the mandible and to evaluate dentition changes
Xi - keyed geometrically to FH and to the pterygoid vertical planes
PM = superpogongion (point at which the shape of the symphysis mentalist changes from convex to concave)
What is the DC point?
point in the center of the condyle neck along the Ba-N plane
What is the PT point?
junction of the pterygomaxillary fissure and the foramen rotundum
What is the C1 point?
condyle
A point on the condyle head in contact with and tangent to the ramus plane
What is the difference between A6 and B6?
A6 = upper molar B6 = lower molar
Points on occlusal plane located to the distal surface of the crowns
Define Gnathion (Gn)
point at the intersection of the facial and mandibular planes
What is the difference between Pog and PO?
Pog = point on the bony symphysis tangent to the facial plane
PO = intersection of the facial plane and the corpus axis
What is the TI point?
point of intersection of the occlusal and facial planes
Frankfort Horizontal is a plane that connects __ to __
porion
orbitale
What is PtV?
vertical line drawn through the distal radiographic outline of the pterygomaxillary fissure and perpendicular to the FH
What plane divides the face and cranium?
Basion-Nasion plane
Describe Down’s AB plane
measures the relation of the anterior limit of the apical bases to each other relative to the facial line
Points A and B are joined by a line which is extended to form an angle with the line N-Pog
Estimates the difficulty in obtaining correct axial inclination and incisor relationship
Describe Down’s MPA
Relates line tangent to Gonial angle to lowest point on the symphysis (Me)
Note that Down’s MPA is measured differently than Rickett’s!
Describe Down’s Y-Growth axis
S-Gn. acute angle with FH = facial angle. Larger = class 2
Describe Down’s Facial angle
measures degree of retrusion or protrusion of the lower jaw in relation to the upper face
N-Pog intersecting with FH
Larger angle = more prominent chin
What is the Mean SNA angle?
82
What is the mean SNB angle?
80
What is the mean interincisal angle?
130
True or false.. According to Steiner, ideally the distance between Pog to NB line is equal to L1 to NB line both equalling 4mm
true however a 2mm discrepancy between the two is acceptable. over 4mm discrepancy means corrective measures indicated
Define Basion
lowest point on the anterior rim of the foramen magnum
How do you find Gonion?
point of curvature of the angle of the mandible located by bisecting the angle formed by lines tangent to the posterior ramus and the inferior border of the mandible
Define porion
most superiorly positioned point of the external auditory meatus
