Sectional Matrix Reading Operative Midterm

T/F Sectional matrix techniques offer more predictable solutions to achieving contact areas when placing direct interproximal posterior composites than circumferential matrix techniques

True

What is a major barrier to sectional matrix use?

Technique sensitive, difficult for inexperienced users

What is the most common isolation technique used for placement of amalgam and composite restorations

Tofflemeyer

Amalgam is _______ placed

actively

composite is ________ placed

passively

Passive placement means

there is a limited force imparted and maintained during placement before curing

What explains the reason why composites perform less well than amalgams on posterior restorations in terms of contact point creation and food impaction

shrinkage

Sectional matrix bands are used in combination of a ______

seperating ring

Provides seperation of the teeth and stabilizes the matrix coronally, favoring contact area formation

seperating ring

A _______ is more likely than a broad area of contact with a circumferential matrix

single point of contact

________ can give a laterally positioned unsupported marginal ridge which is more susceptible to fracture, and a flatter emergence form from the embrasure with the potential to shred floss

circumferential matrices

Sectional matrices have been shown to result in ______ in the restoration at the contact area

surface concavity

a _____ in the restored surface at the contact area will be inaccessible to cleaning and tend to harbor biofilm

concavity

a sectional matrix aims to create a contact area at the level of _______ of the intact adjacent tooth

maximum convexity

T/F a matrix should be selected such that it extends beyond the extent of the cavity and can be engaged and stabilized

true

the maximum convexity of the matrix should be positioned _________ with the maximum convexity of the intact adjacent tooth to create an appropriate contact area

against and in contact

matrix should be able to be placed _______, unimpeded by contact with the adjacent tooth

passively

how is a cervical seal and stability achieved?

wooden and plastic wedges

how is seperation of teeth achieved?

wooden wedges, seperation ring

how is a well adapted matrix in contact with the adjacent tooth at point of maximum convexity achieved?

cavity design, matrix selection and placement, restorative material placement

how is coronal stability achieved?

seperating ring (active), unbonded flowable resin (passive)

Stabilization distortion (matrix moving before wedge stabilizes it) can be prevented by?

placing a finger on the matrix

T/F distorted matrices can be burnished in an attempt to re establish the shape at the contact area, but this will ALWAYS result in an uneven external topography

True

How are sectional matrices superior to circumferential matrices?

Their ability to recreate lost interproximal walls in a more anatomical way