Cusp Build-up and Pin Placement Flashcards
The mandibular molar has ___ buccal cusps, ____lingual cusps, ___ buccal groove(s), and ___ lingual groove(s) that extend from the occlusal surface.
3 B cusps
2 L cusps
2 B grooves
1 L groove
How many fossae are in the mandibular molar?
3 (mesial, central, distal)
*mesial and distal are triangular grooves
Mandibular 1st Molars:
The four _____ridges (of mesiobuccal/mesiolingual cusps, and of distobuccal/distolingual cusps) join to form two ______ ridges.
triangular
transverse
True or False: When viewed from the buccal, the 3 buccal cusps of mandibular molars are all close to the same height.
True
However, remember that the distal cusp is narrower mesiodistally
Name the three buccal cusps of mandibular molars.
mesiobuccal, distobuccal, and distal
Placement of a class II amalagam, with the cusp build-up on most of the buccal surface, involves placement with a ________ Toffelmire retainer and an extended-width matrix band.
contra-angle
How is the condensing technique modified when doing a cusp build-up?
“overfill condensing” must be used to account for height of missing cusp
Why would a dentist place a pin?
to HELP RETAIN amalgam when one or more cusps have been lost
Pin holes are drilled entirely within _____ and generally extend _____ deep, with _____ of the pin exposed within the preparation.
dentin
2 mm deep
2 mm exposed
How many pins are placed per cusp?
one
How many pin types are there? What are the types?
three
- Threaded/Screw Type (hole smaller than pin size)-screw
- Cemented (hole larger than pin size)-cement
- Friction Lock (hole smaller than pin size)-tap it in
What is the “general rule” for rubber dam isolation of posterior teeth?
punch holes for ONE tooth behind and TWO teeth in front
True or False: During a cusp build-up procedure, a dentin protector is recommended.
True (ex. copal varnish)
Why can’t a “universal retainer” be used for an MODBA preparation/build-up?
tooth structure must be re-built on the buccal, the part of the band that enters into the retainer slots will not adapt well to the buccal aspect of the tooth
During placement of the matrix band and wedge, the band must extend ______ occlusal to the future marginal ridge and _____ gingival to the gingival margin.
- 5 - 1.5 mm occlusal
0. 5 -1.0 mm gingival
True or False: The marginal ridge should be convex from buccal to lingual.
False, CONCAVE
True or False: Base should not be placed on enamel.
True
If extension of the preparation (from a primary groove toward the cusp tip) is ______ to _____ the distance, consider capping the cusp.
1/2 to 2/3
>2/3 usually cap
Complex amalgam restorations can be used as ____, ____, or ______ restorations.
- Definitive (patient couldn’t afford a crown)
- Foundation (RUC)
- Control (pulp, perio, or caries issues)
Why would amalgam be used as a “control restoration?”
- Pulpal Questions
- Periodontal Questions
- Acute Caries Present
- Severe Caries Present
*Control other issues before placing definitive crowns!
We use the TMS pin system. What does TMS stand for?
thread mate system
What is the drill diameter and pin diameter of the “Regular TMS” pin system? All other pins in this system are ______diameter.
Regular:
Pin = 0.78mm
Drill = 0.68mm
Other pins are of smaller diameter
(minim 0.61, minikin 0.48, minuta 0.38)
Pins used at OSU are made of _____ alloy
titanium
What is the pin characteristic that allows pins to snap off after drilling into the tooth?
“Self Shearing” Pin (small area that is NOT threaded)
The pin drill is ____-shaped and is ____-limited
pear
depth
Make sure the latch-head handpiece is set in the ____direction when using the pin system.
forward
True or False: Pins should be placed at line angles and 2 drill widths in from the DEJ.
True
How deep is a retentive well? How far into the tooth from the DEJ?
- 5 mm deep from pulpal floor
0. 5 mm in from DEJ
What is the “2-2-2-2 Rule?”
2 mm pin hole depth
2 drill diameters inside the DEJ
2 mm length of pin
2 mm amalgam over the pin
If close to the pulp, _____ can be used as an indirect pulp cap to stimulate dentin.
calcium hydroxide (or RMGI)
True or False: ZOE should not be used under composite.
True
What is the purpose for using copal varnish?
seal tubules and prevent sensitivity
