Fall Lecture 3: Matrix Systems for Amalgam Restorations Flashcards
Occlusal portion of matrix band should be here:
1.5 - 2mm above marginal ridge of adjacent tooth and cavosurface margin, proper condensation of amalgam in margin ridge area
Gingival portion of band should extend:
0.5mm below gingiva
Proper hugging of band around tooth allows for:
proper amalgam condensation and contour developement
Which knob tightens the matrix band?
long, inner knob
Do this after wedge placement:
turn knob 1/4 turn to loosen
How to get proper contact area with adjacent tooth?
Burnish the band
What is required for adequate forces to be applied to the amalgam during condensation?
proper confinement of amalgam with matrix band
Hidden margin in Class 2 restoration:
proximal gingival margin
4 parts of Tofflemire:
Head, vise/ slide, rotating spindle, set screw
Two types of the Tofflemire retainer
straight and contra-angled (lingual placement of band)
What are the two types of the Tofflemire retainer based on?
head angulation
2 types of Tofflemire bands:
flat, precontoured
Types of flat bands:
No. 1, 2, 3, 13
Universal band:
No. 1
MOD band:
No. 2, deep gingival margins in proximal aspects of tooth
How are flat bands categorized?
thickness, 0.0010 (for tight contact, Class 2), 0.0015, and 0.0020
Benefit of thicker bands:
resist deformation during condensation
When to burnish the matrix band:
before placing in the matrix band retainer and after placing band
Place wedge before or after tightening the matrix band?
before
When might a band need to be trimmed?
subgingival cavity, trim band in unaffected side of proximal surface of tooth
2 rules for correct placement of matrix system:
Open end of retainer head toward gingiva, smaller circumference of band toward gingiva.
Issues that could arise if matrix band is too tight:
open contact, hinder condensation into proximal cavosurface margin areas.
Post placement burnishing is done with:
a ball burnisher
Other matrix systems:
AutoMatrix System (Dentsply), Denovo Matrix System, T-band Matrix
Do we only use the matrix systems for amalgam? Different systems for composite?
ask
Open side of Tofflemire head should be __ when placed around the tooth:
gingivaly
Open side of Tofflemire head should be __ when the band is installed:
up
The rotating spindle changes:
adjust distance bw slide and head
Locks and unlocks the matrix band:
set screw
When to use a contra-angled Tofflemire:
when placing on lingual side of tooth, angulation helps retainer stay up and not in way of incisors when removing, can be tilted to fit around pos teeth while ant portion is angled up and over incisors
Most commonly used Tofflemire matrix band:
No. 1, universal
Difference bw No.2 and No.3 bands:
Both have projections, 3 is narrower, for premolars, No.2, molars
Tofflemire band to use when doing a Class 2 restoration:
0.0010 inches
Beware of this when using a precontoured band:
the band must be rotated so the trailing edge does not break shape of marginal ridge when being removed
What determines whether you should use a wide or narrow band?
depth of gingival cavosurface margin
What do we check after placing the wedge?
Relationship bw the occlusal surface of the wedge and the gingival cavosurface margin, should be above margin
Bands to use for deep subgingival restorations:
bands with extensions
Turn this to decrease the size of the matrix band:
rotating spindle
Added benefit of confirming that the band is well adapted to the gingival cavosurface margin of the restoration:
helps clear any unsupported enamel
Bands good for complex restorations or amalgam core build ups:
automatrix system, built in retainer, smaller than Tofflemire retainer, cable derive wrench to tighten around tooth
Prewelded band, different sizes, no retainer needed, cut band with bur:
DeNovo Band System
Simple, inexpensive band system
T band system
