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