dental surveying

1. Steps in Surveying
Preparation
Trim sharp edges of a master model with a
plaster knife if needed. Do not trim it with a
model trimmer because water will wet the
model’s surface and the block-out pink wax will
not stick to it.
Do not wet a model, if you want wax to stick to
its surface: block out.
Wet a model, if you do not want wax to stick to
its surface: rims, set up and wax up for try in.
1

2. Read Job1 Work Order,
mark the clasp type on the
master model,
44: L-bar, 34: L-bar
2
Preparation (continued)
TAFE TEACHING LABORATORY WORK ORDER
DATE: Semester 2, 2012 OPERATOR: Dr. A. Clasp
TEETH: SHADE:______________MOULD_____________
JOB TYPE: Mandibular Kennedy Class I (Job 1)
DATE/TIME COMMENTS
SPECIAL TRAY
MMR
TRY IN
RETRY
CASTING
FINISH Week 8, Semester 2, 2012 Finish Job 1 and fit to Master Model.
RESTS: None
CLASPS: 3.4 L-Bar
4.4 L-Bar
MAJOR CONNECTOR: Acrylic
RECIPROCATION: Acrylic
IMMEDIATE EXTRACTIONS:
None
PATIENTS NAME: Mr B. Partial
JOB 1: Mandibular Kennedy Class I

3. Analysing master model
Place and secure master model on the survey table.
3
For left-hander For right-hander
Locking nut:
secure model
on the survey
table
Locking nut:
change and
secure tilt of
survey table
Suggestion: In order to tilt the survey table
easily

4. Analysing master model (continued)
Adjust the survey table to make the occlusal plane
parallel to bench(Zero Tilt).
4
Occlusal plane
Occlusal plane parallel to bench-Zero Tilt
bench

5. Tilt survey table to move the anterior part down,
eliminate undesirable undercuts: 3.4, 4.4 – distal
surface, this is the anterior-posterior tilt for this case.
Analysing master model (continued)
5
3.4-distal surface –
undesirable
undercut -eliminate
4.4-distal surface –
undesirable
undercut -eliminate
down

6. Analysing master model(continued)
Using the analysing rod, lightly contact all teeth surfaces and soft
tissue surfaces to find out where undercuts are. When analysing
tooth, the tip of the rod should be at the level of the free gingival
margin :
Tooth undercut: Anterior Teeth -lingual surface – no undercut
3.4-distal surface –undesirable undercut
3.4-lingual surface –no undercut
3.4-Buccal surface –desirable undercut (clasp)
4.4-distal surface –undesirable undercut
4.4-lingual surface –undesirable undercut
4.4-Buccal surface –desirable undercut(clasp)
Tissue undercut: No tissue undercut
6

7. 3.4-distal surface
7
3.4-buccal surface
3.4-langual surface
4.4-distal surface 4.4-langual surface 4.4-buccal surface

8. Tilt survey table to move the master model laterally (left
side up-right side down or left side down-right side up ) to
minimise and equalise desirable undercuts: 3.4, 4.4 – buccal
surface, this is the left-right tilt for this case.
8
34-Buccal surface –
desirable undercut
(L-bar clasp)
44-Buccal surface –
desirable undercut
(L-bar clasp)

9. Determine the path of insertion
The master model must stay on the survey
table (same plane) until the block out and
trim back finished. Then the master model
can be removed for duplication
9
Anterior-posterior tilt: decided Left-right tilt: decided

10. Tripoding Model
After the path of insertion has been decided, it must be
recorded for future reference. This procedure is referred to as
tripoding. The simplest method of tripoding consists of placing
marks at three widely spaced points on the dental model while
the vertical arm of the surveyor is held at a fixed vertical
position. This will establish three points in the same horizontal
plane and permit the model to be accurately repositioned.
Tripod marks are scribed into the model so that a model may
be taken off the survey table and replaced in the same position
as it was originally in. This allows a duplicate model to be
positioned in the same survey position (horizontal plane) as the
master model was in. The tripod marks must be scribed
reasonably deep, so that they will can be identified in the
duplicate model.
10

11. Tripod master model (continued)
1.Move the analysing rod down until it touches one side
of the land area on the model (near retromolar pad).
Then lock the rod in this position. 2. Move the locking
rod horizontally to anterior area (near midline). 3. Move
the locking rod to other side land area on the model (near
retromolar pad).
11
Down & touch first
Then
Lock nut
1 2
3

12. Tripod master model (continued)
If the locked rod can touch the land area and the
anterior part of the master model, then scribe the model
at these three points and circle the marks with a
permanent marker so
the three marks can be
identified after duplication.
12
The mark is
engraved onto the
model using a le-
cron carver

13. Survey
Unlock the vertical arm and replace the analysing rod with the
red carbon marker. Run the marker around 3.4, 4.4 – buccal,
distal and lingual surfaces and lingual gingival margin of six
anterior teeth. When marking survey lines, ensure that the
carbon tip follows close to the free gingival margin so that you
do not register a false height of contour (survey line).
13
Buccal
Distal
Lingual &
Gingival margin

14. The survey instrument draws the survey lines on the
model so that we can be sure that no rigid part of a
partial denture lies in an undercut. This will affect the
path of insertion and removal the denture. If there were
undercuts, then the partial denture would not fit into
the master model, or if it was forced into the patient’s
mouth, it would snap into place and be impossible to
remove in the clinic.
It should also be noted that oral mucosa can have
undercuts present, as well as teeth. Remember to survey
the mucosa as well as the teeth on the master model.
14
Survey (continued)

15. The denture base (major connector) is
entirely marked on the model showing
flanges and finishing lines around teeth
(food lines in the palate for maxillary
model). The rests and clasps are also drawn
on.
No partial denture can be designed without
surveying the master model.
15
Draw design on master model
(copy the clinician’s design from work order)

16. Draw design on master model (continued)
(copy the clinician’s design from work order)
16
1. Draw denture finish line: must above survey line on every tooth
2. Draw clasps: L-bar
clasp on 3.4 & 4.4.
the smile face: all
under survey line

17. Block out undesirable undercuts (below survey
lines only, not above survey lines) and gingival
margins with pink wax
17
Block out (continued)

18. As well as the undesirable undercuts being blocked
out with wax, the gingival margins of the teeth that
will be covered by the denture base are relieved
with wax. This is because the pressure of the
denture base on the cervical margins can cause pain
and ulceration to the patient.
During surveying, if the area of the mucosa that a
bar clasp arm will cross has an undercut, then this
area must be block out. This is because the clasp
arm could ulcerate the mucosa, if it comes into
contact with mucosa.
18
Block out (continued)

19. Cut back block out wax
19
Replace the carbon marker with
the wax scraper. Trim the
excess pink wax on the distal
and lingual surfaces of 3.4 and
4.4 until the scraper contacts
the tooth surface. Do not
damage the tooth surface.
Use a la cron to remove the
excess pink wax around the
gingival margin.

20. 20
Cut back block out wax (continued)
The master model after block
out and trim back (undesirable
undercuts and gingival margin).
The master model is ready for
duplication, now it can be removed
from the survey table