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
