fized prosth 2 final

too subgingival finishline

contraindication for digital impression

traditional impression (PVS)

best method of impression for deep subgingival finish line

scan, CAD design, model, CAM mill, crystalize/sintering, stain/glaze

steps of digital workup for crown

0.3mm

MINIMUM thickness of ZIRCONIA COPING (3Y zirconia)

fracture strength greatly decreases (3000 down to 100)

what happens once feldspathic porcelain is layered on top of coping (zirconia)

monolithic zirconia

for POSTERIOR teeth the most common material utilized with digital workflow is:

restricted CAM options, limited choices of restorative materials

DISADVANTAGES of DIGITAL SCANNING with E4D Dentist system or CEREC (CAD/CAM both done in office)

complete systems and efficiency

ADVANTAGES of DIGITAL SCANNING with E4D Dentist system or CEREC

non-restricted CAM options, more choices of restorative materials

ADVANTAGES of DIGITAL SCANNING with TRIOS/open system

TRIOS/open system

Designed for digital impression-taking and integration with dental lab workflows, lab does the designing and crown production

true

T/F ZIRCONIA restorations based on DIGITAL IMPRESSIONS are comparable to the conventional impression with regard to the marginal fit

true

T/F NO statistical sig. was observed between digital and conventional impressions regarding the marginal discrepancy of SINGLE UNIT CERAMIC crowns

triple tray

impression tray used for SINGLE CROWN

most distal abutment

when is a TRIPLE TRAY CONTRAINDICATED (NOT ALLOWED)

making provisional

what method can serve as a last check of proper reduction prior to taking final impression

immediately check clearance, patient comfort, time, efficiancy

ADVANTAGES of digital workflow

Wet milling

MILLING METHOD needed for LITHIUM DISILICATE and TITANIUM

Dry milling

MILLING METHOD for ZIRCONIA

wet milling

milling method that provides superior, smoother finishes on delicate materials

dry milling

milling method that is faster, cleaner, and better for high-production, opaque restorations

wet milling

Use water or specialized coolant to manage heat, preventing material damage during the milling of sensitive materials like glass-ceramics, hybrid composites, and titanium

dry milling

Use compressed air or suction to remove debris, designed for softer materials like pre-sintered zirconia, PMMA, and wax.

sinter

zirconia at 1,500 degrees for 8.5hrs

60 to 1,200

SINTERING of zirconia after milling increase the strength from ____ to ____ MPa

crystalize

lithium disilicate at 850 degrees for 60min after milling

true

T/F LITHIUM DISILICATE is used for same day crown delivery due to the quickness of the crystalization stage

150 to 360

crystalization of LITHIUM DISILICATE after milling increases the strength from ____ to ___ MPa

pre sintering it is very soft (60MPa)

why can zirconia be milled by DRY MILLING?

work to be performed, materials to use, accurate impressions, casts, occlusal reg.,

what information/materials should the dentist provide the lab with

crown margins, post palatal seal, denture borders, design of removable partial dentures

what is under the responsability of the DENTIST to identify prior to sending work to the lab

true

T/F the dentist should furnish instruction regarding preferred materials, coloration, and description of prosthetic teeth to be utilized for fixed or removable prosthesis

true

T/F the dentist needs to provide verbal or written approval to proceed with a laboratory procedure, or make any appropriate changes to the written instructions as the dentist deems necessary

true

T/F anything sent to the lab should be disinfected

return to lab

what should the dentist do if fit or shade selection is incorrect

true

T/F the lab technician should follow the guidelines set by the dentist's written instructions when fabricating a restoration

diagnostic cast

replicas or models of a patients dental structures for diagnosis and treatment planning

arbitrary hinge axis

facebow that approximates the HORIZONTAL transverse axis and rely on anatomic average values

earbow and kois dento-facial analyzer

examples of arbitrary hinge axis facebows

kois dento-facial analyzer

an average axis facebow that relates maxillary incisal edge position, maxillary occlusal plane, dental midline, and facial midline to the HORIZON

horizon

what does the KOIS DENTO-FACIAL analyzer use as a reference plane

diagnostic waxing

a waxing of intended restorative contours on dental casts for the purpose fo evaluation and planning restorations

duplicate cast, matrices, stents, and reduction guides

tools made from diagnostic casting that are necessary for a number of surgical and restorative procedures

clear finishline and soft tissue contour

criteria for a good MASTER CAST

false

T/F if the prepped tooth is on #15 (the most distal tooth) it is satisfactory to use a triple tray to take the impression

alginate in stock metal tray

If a full arch impression is needed, what material is used for the OPPOSING tray

PVS in plastic tray

If a full arch impression is needed what meterial is used for the PREP tray

bite/occlusal clearance is not accurate

why can triple tray not be used for prep on most distal abutment?

monolithic

which type of restoration is STAINED?

laminated

which type of restorations is LAYERED?

lithium disilicate and zirconia (monolithic materials)

which materials can be used for MILLING?

diagnostic waxing and interim restorations

the lab determines restoration contour from?

working casts, material selection, restoration contour, occlusal scheme, shade

what should the dentist provide to the lab for restoration fabrication

true (remains in MIP ideally)

T/F for a single posterior crown patients occlusal scheme is NOT changed

fully balanced

bilateral, simultaneous, anterior and posterior occlusal contact of teeth in centric and eccentric postitions

fully balanced

which occlusal/guidance scheme has the primary purpose of stabilizing mucosal supported removable prostheses

mutually protected occlusion

posterior teeth prevent excessive contact of anterior in MIP. anterior disengage posterior in all mandibular excursive movements

mutually protected occlusion (MPO)

what occlusal scheme is the goal

before preparation

when should shade be selected?

natural light

ideal lighting for shade selection

neutral color

ideal surrounding when selecting shade

hue

color, ex: red, green yellow, determined by wavelength of light

chroma

saturation, intensity/strength of hue (from white base)

value

lightness or darkness of a color (brightness)

A

VITA hue category that is REDDISH BROWN

B

VITA hue category that is REDDISH YELLOW

C

VITA hue category that is GRAYISH

D

VITA hue category that is REDDISH-GRAY

true

T/F the clinical success of a crown or bridge depends on how we deliver the definitive prosthesis

true

T/F ceramic material can be used for every indirect restoration

retention

cements with HIGH COMPRESSION and TENSILE STRENGTH have stronger ______

high compression and tensile strength

components of cement that provide stronger retention

luting

cementation with little to no chemical adehesion, relies on MECHANICAL retention

bonding

cementation forms chemical and/or micromechanical bond to tooth

bonding

which type of cement have improved retention and strength of restoration

true

T/F tooth preparation design will influence the choice of cement

3-4

an increase wall height of _____ mm was associated with sig. increase in fracture resistance and can compensate for missing interproximal wall

true

T/F retentive features in crown preparations are for METAL substrates ONLY

rounded

ZIRCONIA preparations must always be _____ to account for milling burs

negative error (too much material taken away)

OVERMILLING to account for sharpness of a preparation is considered

true

T/F restorative materials will influence the choice of cement

sandblast, rinse/dry, prime with adhesive (20sec), air dry (5 sec)

pretreatment for metal and ceramo-metal restorations

true

T/F regardless of their applications or fabrications technique, after firing, dental porcelains are composed of at least 2 phases

glassy, crystalline

dental porcelains have a ______ phase surrounding a _____ phase

60

FELSPATHIC porcelain is ___% vol glass

35

LITHIUM DISILICATE is ____ %vol glass

<5

ZIRCONIA is ____ vol% glass

hydrofluoric acid

silica contaning CERAMICs are able to be ETCHED by

9.5% hydrofluoric acid gel for 1 min

what is used to etch FELDSPATHIC PORCELAIN and LEUCITE-REINFORCED glass ceramic

fluorosilicate (must be rinsed off, inhibits bonding)

what is formed when felspathic porcelain is etched?

4.5% hydroflouric acid for 20 sec

what is used to etch LITHIUM DISILICATE

feldspathic and leucite have higher glassy (silica) matrix content

why do FELDSPATHIC porcelain and leucite reinforced glass ceramic require a HIGHER concentration of hydrofluoric acid for a longer period of time than lithium disilicate

true

T/F acid conditioning of ceramic with hydrofluoric acid reduces stress concentrators and increases overall strength

1

after etching with HF, ceramic surface should be rinsed with water for ___ min

extraorally

HYDROFLUORIC acid etching (of the prosthetic) should be done ____

false

T/F hydroflouric acid etching is reccommended for ZIRCONIA

silane coupling agent

After etching dental glass-ceramics (like lithium disilicate or feldspathic porcelain) with hydrofluoric acid (HF), a ________is the primary, gold-standard priming material used to create a chemical bond

small amount of glass matrix and dense crystal network

why is etching zirconia with HF (hydroflouric acid) not recommended?

sandblasting with 50 micron aluminum oxide for 10-20sec

how is ZIRCONIA prepped for cementation?

true

T/F clinicians should use airborne particle abrasion to clean and rough zirconia INTAGLIO surfaces to provide micromechanical retention

false

T/F clinicians should use airborne partical abrasion to clean and roughen lithium disilicate based ceramic INTAGLIO surfaces to provide micromechanical retention