VISUAL PERCEPTION AND VISUALIZATION-RELATED
EVALUATION
Please answer all of the following questions as well as
possible. If the question doesn’t make
sense to you, move on to the next question.
This evaluation relates to BOTH interpretation of the language wherein
the perception problem is described, AND the actual visualization required to
answer the question. The execution of
dental procedures requires that you develop a profound three dimensional sense,
that you learn to communicate in these terms, and that you relate your physical
actions to these concepts by “hand-eye” coordination. In reality – it is the hand, the eye, and the
perceptive mind that determines your success in optimizing your
performance. While this evaluation only
introduces you to the mental part of this equation – at DDS we emphasize the
complete skill set by developing each area and how everything works together.
While some of these questions are dental related and some
are strictly geometric – all relate to the need to “see” things in your mind
and relate them to descriptive language.
1.
In order to prepare the proximal surface of a
tooth for a full gold crown with a tapered diamond bur, what is the surest way
to ensure that you do not damage the adjacent tooth?
There
are two answers that you need to elaborate on:
a.
Describe how you are DOING the work so the
adjacent tooth does not have to be damaged
b.
What allows you to KNOW that you are not
damaging the adjacent tooth
2.
What is the principle method used to ensure that
the vertical angulation of your bur is appropriate before cutting the tooth
structure?
3.
Consider a FLAT plane as part of a dental
preparation. This plane may best be
described as:
a.
Perpendicular to the tooth axis
b.
Parallel to the tooth axis
c.
Neither of the above
d.
Could be either of the above
4.
If you are using a cylindrical diamond abrasive
bur with a round end to cut an axial surface of a tooth, how far should you let
the end of the bur penetrate axially into the tooth structure to achieve a
final preparation which has a gingivally sloping angle as you approach the
margin?
a.
1/3
b.
½
c.
2/3
d.
Cannot be determined
5.
In a full crown preparation for gold, the axial
walls are ROUGHLY parallel to the axis of the tooth, but must converge to some
extent. Textbooks specify 6 degress of
convergence occlusally, while the average in the dental community tends to be
much higher. Why is it important to
design a preparation with carefully controlled taper?
a.
To ensure that the laboratory can achieve
natural contours for the crown
b.
To ensure optimal retention for the crown
c.
‘To achieve “draw”
d.
To enable optimum axial reduction at the
gingival margin
e.
All of the above
f.
Only three of the above
6.
Gingival divergence of the F/L proximal walls of
a class II amalgam preparation is NOT useful for:
a.
Retention
b.
Conservative removal of F/L surface
demineralization in the enamel at the gingival 1/3 of these walls
c.
Establishing a ninety degree exit angle for the
proximal margins of these walls without undermining enamel.
7.
If you wish to view along the tooth axis for
tooth #19 (“Universal” numbering system):
a.
You look vertically downward over the patient’s
left eye
b.
You look vertically downward over the patient’s
right eye
c.
You look vertically downward using the mirror
while your line of site is parallel to the occlusal plane and along the arch.
8.
The long axis of a mandibular first molar
approaches more near to which root terminus and why?
a.
Distal because roots curve distally
b.
Distal because roots curve mesially
c.
Mesial because roots curve distally
d.
Mesial because roots curve mesially
9.
In order to achieve occlusal convergence of
opposi9te walls during crown preparation, which walls would require the largest
amount of tooth reduction, as measured by horizontal reduction measured at the
occlusal third?
a.
Mesial and distal walls for maxillary central
incisor of a typical teenager
b.
M/D walls for a maxillary central of a typical
middle-\aged patient
c.
F/L walls of maxillary first premolar
10.
Which is the wisest viewing direction to use if
you are trying to control the lingual taper during axial reduction of a man
dibular first molar of a crown preparation?
a.
Vertically downward
b.
Perpendicular to the lingual surface of the
tooth
c.
Parallel to the lingual surface, looking along
the arch
11.
What is the best viewing directrion for use
while trying to achieve a flat pulpal floor on a mandibular molar conventional
class II preparation?
a.
Vertically downward
b.
Along the arch looking as much as possible
gingivally
c.
Along the arch looking as much as possible
parallel to the pulpal wall.
12.
Consider the cycloid as a geometric form. It is made by tracing arcs between apices of
an equilateral triangle using the third apex as the center of each of the three
arcs. If a log were made with a
cycloidal cross-section and this were used to roll under a heavy flat object, how
much would that object bump up and down during the rolling?
a.
Not at all
b.
Half the radius of the arc
c.
The same as if it were a wheel of this shape
with the axis in the center.
13.
Consider the straight pin whose head, where the
shaft connects, has an outer surface which is slightly curved, following part
of the surface o f a sphere. If the pin
were to be embedded in a rubber balloon with the same surface curvature of the
head of the pin, what would be the wisest size for the balloon?
a.
Diameter equals half the length of the pin
b.
Diameter equals length of the pin
c.
Diameter larger than length of pin.
14.
Consider a glazed, raised donut, which
approximates the geometric form of a torus.
For the smallest circle that can be drawn on the surface of the torus,
which part is most parallel to the axis of the torus?
a.
The part closest to the axis
b.
The part farthest from the axis
c.
The parts on the “top” and “Bottom”
d.
Parts approximating where your teeth would cut
into it while taking a bite.
e. Both "a" and "b" above.
15.
Consider
a baseball, with the seam stitched to n the two halves of the leather, or a
tennis ball where the two halves are joined.
Each of the two pieces that are stitched together has a shape when laid
flat, like a “bumbell” – being bulbous at each end with a narrow isthmus
between. If the b all were oriented
about a vertical axis such that the bulbous ends for one piece were “upward”,
where would the axis pass through the “lower” side of the ball relative to the
isthmus of that piece?
a.
Through the seam at one side of the isthmus
b.
Exactly through the center of the isthmus –
equidistant from the seams and from the bulbous ends
c.
It does not pass through the isthmus at all on
the bottom, but does on the top.
16.
Consider a perfect CUBE. There are four lines that can be drawn
between each of the four sets of vertices that are farethest apart. They are called body diagonals. Do all four of these lines intersect?
a.
Yes
b.
No
17.
For the cube above: How many of the twelve FACE DIAGONALS
intersect another one?
a.
Twelve
b.
Six
c.
Only three
18.
For the cube above: How many face diagonals are parallel to
another one?
a.
Twelve
b.
Six
c.
Only three
19.
Can two lines be perpendicular even if they
don’t intersect?
a.
Yes
b.
No
20.
Consider a circle in two dimensions, and a
straight line which lies in the same plane as the circle. What are the possible numbers of points at
which these two objects can intersect?
a.
Two
b.
One
c.
One or two
d.
One, two or zero
21.
Consider a bur with a straight side and a
maxillary central incisor with a line drawn on the facial surface, parallel to
the incisal edge as viewed from the facial and equidistant from the incisal
edge and the CEJ at its most gingival level on the facial surface. How many possible vertical angles are there
where the bur touches the line, centered mesiodistally?
a.
Four
b.
Three
c.
Two
d.
Only one
22.
If you see an three dimensional object from one
direction and it appears to be a circle, and from a perpendicular direction it
appears to be a square, what is the actual shape of the object?
a.
It is a cube
b.
It is a cylinder
c.
It is a pyramid with a circular base
23.
Can you imagine an object that from three
different mutually perpendicular viewing directions is seen to be a circle, a
triangle and a square?
a.
Yes
b.
No, but I am sure that it doesn’t exist
c.
No, but I believe it might exist