Second Semester Flashcards
Describe the characteristics of a patient that would be at high risk of substantial external root resorption?
Already short roots
Conical/blunted root tips
Teeth need to be moved a long distance (closing extraction space)
Pt needs camouflage treatment (roots may bump against cortical plate)
Describe the two normal postural lip positions
Relaxed: lips apart, relaxed, and hanging loosely with no contraction
Closed lip: lips are lightly touching to seal the oral cavity, minimal contraction to achieve this anterior closure
Describe the abnormal lip position present in a class 2 div 1 case with significant overjet.
Closed lip: light contact between lower lip and maxillary incisors
Greater mentalis strain is noted to achieve closure
Describe three techniques to find the relaxed lip position
For all three techniques, FH should be parallel to floor.
1) lightly jiggle mandible up and down as if trying to locate CR
2) Stroke the lips with fingers to relax lips and form the space between lips
3) instruct pt to relax lips
Which is the least reliable method to find relaxed lip position?
Instructing the patient to relax their lips
When evaluating lip posture should the teeth be together or apart?
Together
The interlabial gap is influenced by what two things?
Length of the lips
Variation in skeletal height in the anterior portion of face
It has been noted that the malocclusion with the shortest upper lip length is class ___
2 div 1
A useful plane to evaluate lip protrusion is ____
Subnasale - soft tissue pogonion
On average, the upper lip is ___ and the lower lip is ___ anterior to the subnasale-soft tissue pogonion line
- 5mm
2. 2mm
What is the typical angle for the nasolabial angle?
74 degrees
The ___ should be considered the most important element in determining a stable position for the incisors
Lips
True or false… a retruded lip pressed against a lower incisor is less suggestive of the desirability of protruding the lower incisor during treatment than a lip that is protruded and lying away from the incisor
True
Normally, a relaxed lower lip will contact the ___ at the ___
Lower incisor
Junction of its incisal and middle thirds
True or false… if the interlabial gap is large, protrusion of the teeth is more stable.
False
Without considering growth, the most dramatic facial changes following retrusion of teeth are seen in cases where there is a ___
Large interlabial gap
___ relaxed lip posture is associated with protrusive dentition and ___relaxed lip posture is associated with retrusive dentition
Protrusive
Retrusive
Describe the lower lip resting position in Class 2 div 1 and Class 2 div 2.
Class 2 div 1: lower lip rests lingual to the upper incisors and exerts labial pressure
Class 2 div 2: lower lip rests labial to the upper incisors and exerts lingual pressure
What is the soft tissue facial angle?
Angle between FH and line from soft-tissue nasion to soft-tissue chin
91+/- 7 degrees
How did Holdaway measure nose prominence?
Line perpendicular to FH, tangent to vermillion of upper lip. Measure of tip of nose to this line
Normally 16mm . (<14 = small, >24 = large)
How did Holdaway measure the superior sulcus depth?
Used the same line to measure nose prominence
3mm ideal (less than 1.5 should be avoided)
This is the most frequently criticized area with retraction of anterior teeth
Holdaway found that upper lip thickness measured at the vermillion follows tooth movement. Notably, very thick lips (~__mm) will be slow to follow tooth movement, very thin lips (~___mm) will be fast to follow tooth movement
16mm+
12mm-
The lips and chin should line up near the ___
H line
What is the ratio for esthetic balance of upper face (glabella to subnasale) to lower face (subnasale to soft-tissue menton)?
1:1