les journÉes dentaires internationales du quÉbec...

LES JOURNÉES DENTAIRES INTERNATIONALES

DU QUÉBEC 2016

PRESENTS

SMILE LINE ESTHETICS WITH CROWNS, VENEERS AND IMPLANTS

BY

DOCTOR GEORGE PRIEST

SUNDAY, MAY 29, 2016 FROM 8:30 A.M. TO 3:30 P.M.

ROOM 513EF

ENDORSEMENT AND RESPONSIBILITY DISCLAIMER The Journées dentaires internationales du Québec (JDIQ) and their sponsor, the Ordre des dentistes du Québec (ODQ), make every effort to present high calibre clinicians in their respective areas of expertise. The presentations of the speakers in no way imply endorsement of any opinion, product, technique or service presented in the courses. The JDIQ and the ODQ specifically disclaim responsibility for any material presented.

Smile line esthetics with crowns and veneers George Priest, DMD

© 2016 Priest Prosthodontics, LLC1

George Priest, DMD

Board Certified Prosthodontist

Hilton Head Island, SC

Smile line esthetics with

crowns veneers and implants

Part 1

Agenda

• The smile line defined

• Smile line concepts and full crown

restorations

• Esthetics and ceramic veneers

• Esthetic integration of dental implants

Agenda


restorations



Frush JP, Fisher RD. The dynesthetic

interpretation of the dentogenic concept. J

Prosthet Dent 1958;8(4):558-581.

The smile line is a curve whose path

follows the incisal edges of the

central incisors through the tips of

the canines and this curve is in

harmony with the upper border of

the lower lip

The illusion of the smile line

The only true curve is in the

occlusal plane

“Smile line” is primarily created

by tilting the occlusal plane

upward or downwardPriest G. Optimal smile line esthetics for edentulous and

dentate patients. Am J Esthet Dent 2012;188-198.

TILTING THE PLANE upward

posteriorly OR downward anteriorly

INCREASES THE CURVE

TILTING THE PLANE downward

posteriorly OR upward anteriorly

REVERSES THE CURVE



Occlusal plane angle and

facial esthetics

Examining facial images of dentate subjects with

digitally altered occlusal plane angles, observers

preferred smiles with angles between 5 and 15

degrees and a 0 degree angle was judged as the

most unattractive.

Batwa W, Hunt NP, Petrie A. Effect of occlusal plane on

smile attractiveness. Angle Orthod 2012;82:218-223.

Occlusal plane and face bow

accuracy

• 5 facebow systems tested on a

phantom head

• None of the systems tested exactly

replicated the sagittal and coronal

orientation of the occlusal plane

Maveli TC, et al. In vitro comparison of the maxillary

occlusal plane orientation obtained with five facebow

systems. J Prosthet Dent 2015;115:566-573.

Campers Plane

• Campers lane fell within 5 degrees

of the actual occlusal plane in only

42% of examined subjects

Priest G, Wilson M. An evaluation of benchmarks for

esthetic orientation of the occlusal plane. J Prosthet Dent;

accepted for publication 5/11/16.



Agenda


restorations

Tooth proportions

• 146 extracted teeth

• Measured anatomic lengths, from CEJ as opposed to clinical lengths

• Approximately 1 mm longer than clinical crown lengths

• Low ratios dominated by length

• Increased width/length ratio has aging effect

Magne P, Gallucci GO, Belser UC. Anatomic crown

width/length ratios of unworn and worn maxillary teeth in

white subjects. J Prosthet Dent 2003;89:453-461.

Average tooth proportions

Width Length W/L

Central9.10

(8.46-11.07)

11.69

(10.70-13.5)

0.78

(0.71-0.84

Lateral7.07

(5.51-8.22)

9.75

(8.19-11.51)

0.73

(0.57-0.83)

Canine7.90

(6.80-9.02)

10.83

(9.71-12.94)

0.73

(0.60-0.82)

Premolar7.84

(6.61-8.84)

9.33

(7.66-10.45)

0.84

(0.65-0.95)



Tooth proportions• U. Seville, 412 healthy adults

• Measured clinical lengths, from margin, as opposed to anatomical lengths

• Golden proportion not found

• Sex should be taken into account when estimating tooth size

• Significant differences, men having greater values for both length and width

Orozco-Varo et al. Biometric analysis of the clinical crown

and the width/length ratio in the maxillary anterior region. J

Prosthet Dent 2015;113:565-570.

Average tooth proportions

Width Length W/L

Central8.71 10.23 0.85

Lateral6.75 8.59 0.79

Canine7.81 9.93 0.79

Digital caliper

• Measures– Sizes and proportions of teeth

– Sizes and proportions of waxings

– Implant spaces

–Orthodontic spacing

– Edentulous spaces

– Interarch space

– Sizes for denture tooth selection



Restoration and preparation

(not stump) shade• Take several digital images from

different angles

• Keep tabs in same plane as teeth

• Images next to prepare and

unprepared teeth

• Eliminate glare

• Do not send hard copies

• Email, FTP, Rx Connect

Lithium disilicate crowns

• Preparations much more

conservative than for metal ceramic

crowns

Priest G. Increasing all-ceramic treatment

durability in the esthetic zone using lithium

disilicate restorations. J Cosmet Dent

2011;27:99-108

Teaching all ceramic crowns

• All North American dental schools

include teaching and placement of

PFM restorations in their curriculum,

but only one-third teach ceramic-

based crowns

Ben-Gal G, et al. Teaching new materials and

techniques for fixed dental prostheses in dental

schools in the United States and Canada: a survey.

J Prosthodont 2015;24:598-601.



Shade selection protocol

• Take several digital images with

selected tab(s) in place– Examine on monitor to verify accuracy

– Adjust shade and take new images if shade change

• Images are for comparative purposes

only. Lab is to match tabs, not images!

• Lab (or dentist) should also take images

of final restorations adjacent to tabs

prior to seating appointment

21

Cementation protocol for

lithium disilicate crowns• Unlike zirconia, lithium disilicate is

etchable

• Silinate internal surface

• Apply bond to teeth

• Seat with dual cure resin cement

–Kurrary Panavia F

–Ivoclar Multilink

–VOCO Futurabond and Bifix

Cementation protocol, lithium disilicate

• U. North Carolina

• Lithium-disilicate glass-ceramic crowns

can be either cemented or bonded, but

at this time it is recommended that they

be etched and bonded using a self-

adhesive dual-cure resin cement.

Ahmed SN, et al. Evaluation of contemporary ceramic materials. J Esthet

Restorative Dent 2015;27:59-62.



Cementation protocol, lithium disilicate

• U. Poland

• Zirconia ceramic disks bonded to bovine

incisors using zinc phosphate, zinc

polycarboxylate, Eco-Link, Panavia F

2.0, Clearfil SA Cement, MaxCement

Elite and GC Fugi Plus

• Strongest bond between zirconia and

tooth obtained with Panavia F. 2.0

Prylinska-Czyzewska A, et al. Various cements and their effects on bond

strength of zirconia ceramic to enamel and dentin. Int J Prosthodont

2015;28:279-281.

Sensitivity prevention• Remove primers from refrigerator and

allow to reach room temp

• Do not overdry prep. Surface should

be moist/glistening to avoid pooling

• Scrub primer on dentin 15 secs,

enamel 30 secs. Avoid overetching

• Air dry primer to discontinue etch

• Prep should show uniform gloss

• Avoid contamination

Success of lithium disilicate• Italy, private practice study, 12-72 mos.

• 860 lithium disilicate crowns

• Teeth, implants, abutments, onlays and

veneers

• Modified CDA criteria

• Cumulative survival and success, 95-100%

Fabbri G, et al. Clinical evaluation of 860 anterior and

posterior lithium disilicate restorations: retrospective study

with a mean follow-up of 3 years and a maximum

observational period of 6 years. Int J Periodont Restorative

Dent 2014;34:165-277.



Success of lithium disilicate• Ege U, Izmir, Turkey

• 121 lithium disilicate crowns in 35 patients

between 2001 and 2007

• 10 crowns fractured

• Cumulative survival rate 87.1% after mean of

40.6 months

• Location did not affect survival. Endo treated

teeth without post and core exhibited higher

failure rate

Toman M, et al. Clinical evaluation of 121 lithium disilicate

all-ceramic crowns up to 9 years. Quintessence Int

2015;46:189-197.

Marginal display• Tongi U, China

• 100 single metal-ceramic crowns on maxillary

centrals for 100 patients

• Failure free rate over 5-years for thin biotype,

78%, significantly lower than thick gingival

biotype, 94%

• Restored teeth with thin biotype exhibited more

gingival recession (1 mm) than control teeth

(0.3 mm)

Tao J, et al. A follow-up study of up to 5 years of metal-

ceramic crowns in maxillary central incisors for different

gingival biotypes. Int J Periodontics Restorative Dent

2014;34:e85-e92.

Communicate with the lab

• Communication and involvement are

essential for success

• How you communicate as significant

as what you communicate

• Review envisioned result with lab

• Provide too much detail as opposed to

too little

• Scripted digital images for

communicating color and contours



Cord retraction is procedure

and biotype specific

• Crowns– Two cords for thicker biotype, one for thin

• Thinner biotype retracts more apically than

thick

• May leave the single cord when impressing

– Thinner cords for thinner biotype

– Two cords when hemorrhage control an

issue

–Cord always need with subgingival

restorations

Cord retraction technique

• Select the first cord predicated on

biotype and sulcular depth

• Cleanly cut piece slightly longer

than you need and use a good pair

of scissors

• Beginning from the palatal or lingual

aspect, place the cord around the

tooth

Cord retraction technique

• As you reach other end, cleanly cut

cord so it approaches, but doesn’t

overlap, the other end

• Select the next cord, usually one

gauge larger and repeat process,

beginning at a different location on

palatal or lingual aspect of tooth

• If entire cord not visible, laser

excess or add small piece of cord



2 cord impression technique

• Protects soft tissue

• Little to no bleeding when leaving

first cord in place

• Subgingival margins completely

visible

• Provides thicker band of impression

material, less likely to tear

Impression accuracy

• Full arch impressions using Identium,

Impregum and alginate

• Significant differences between alginate

and other materials

• Identium VSE 17µ “extremely accurate”

<Impregrum 35µ<alginate 162µ

• TRIOS Color, most accurate tested

scanner, 42µ

Ender A, Attin T, Mehl A. In vivo precision of conventional

and digital methods of obtaining complete-arch dental

impressions. J Prosthet Dent 2016;115:313-320.

Zirconia based crowns

To form a strong bond to zirconia-based

ceramics, the bonded surface must be

mechanically roughened (sandblasting),

free of contaminants, and chemically

primed prior to cementation.

Bunek SS, Swift EJ Jr. Contemporary ceramics and cements. J

Esthet Restorative Dent 2014;26:297-301.




While phosphoric acid can be an

effective cleaning agent for saliva-

contamination for lithium disilicate, it is

contraindicated for zirconia. Best way to

treat contaminated surfaces is by

sandblasting or using Ivoclean

Alex G. Universal adhesives: the next evolution in adhesive

dentistry? Compendium 2015;36:15-26.


• Italian Academy of Prosthetic Dentistry

• 398 patients in private practices

• 1,132 porcelain veneered zirconia

based crowns

• Observed for 5 years

• 98%cumulative survival rate

Monaco C, et al. Clinical evaluation of 1,132 zirconia-based

single crowns: a retrospective cohort study from AIOP Clinical

Research group. Int J Prosthodont 2013;26:435-442.


• U. Penn survey of 13 private

practitioners

• 2,182 single crowns over 7.4 years

• Made by 1 lab using Noritake CZR

• 99.3% and 99.2% survival of PFMs

and PFS crown

Mozer F, et al. A retrospective survey on long-term survival

of posterior zirconia and porcelain-fused-to-metal crowns in

private practice. Quintessence Int 2014;45:31-38.




• 7 laboratory studies of 142 eligible met

study criteria

• In all studies, enamel wear rates were

lower between zirconia/enamel than

enamel/enamel

• Polishing recommended for full-contour

zirconia restoration due to favorable

wear behavior

Passos SP, et al. In vitro wear behavior of zirconia opposing

enamel: a systematic review. J Prosthodont 2014:23:593-601.

Zirconia based crowns• 148 patients with 618 single-or multiple-

unit zirconia-based (Lava) crowns from

Jan 2007 to Dec 2008.

• A core and/or veneer fracture that

required replacement of restoration

considered a failure

• At 5-year follow-up, no zirconia core

fractures, 12 veneer fractures. CSR

98.1%Güncü MB et al. Zirconia-based crowns up to 5 years in function: a

retrospective clinical study and evaluation of prosthetic restorations and

failures. Int J Prosthodont 2015;28:152-157.

Ceramic Crown Properties Hierarchy

• Strength

– Full contour zirconia

– Full contour lithium

disilicate

– Layered zirconia

– Layered lithium

disilicate

• Esthetics

– Layered lithium

disilicate

– Layered zirconia

– Full contour lithium

disilicate

– Full contour zirconia



Ceramic strengths

• U. North Carolina

• Layered e.max more esthetic, but seem

to fracture at twice the rate of monolithic

crowns

• One problem with layered zirconia is

cohesive chipping of veneer ceramic, 5X

more frequent than with PFM



Ceramic strengths

• Monolithic zirconia restorations have

only been in use for a few years, so no

long-term clinical trials available

• Relatively opaque, so major indication

for posterior teeth where esthetics not

critical, especially for second molars



Retention

• Relatively retentive preps: Dual cure

resin cement or conventional

cement

• Short and non-retentive preps: Dual

cure resin cement like Panavia F

• Short preps on molars: full zirconia

with dual cure resin cement:,

sandblasted internal surface,

Ivoclean and Panavia F



One-step impression technique

• Remove top cord when using 2 cord

technique

• Inject light bodied material

• Blow material into sulcus until you

can see the margins

• Inject again

• Seat tray with medium bodied

material

Review of intraoral scanners

• Cerec (now Omnican), Lava (now

True Definition), iTero, E4D (now

Planscan), TRIOS

Ting-shu S, Jian S. Intraoral digital impression

technique: a review. J Prosthodont 2015;24:3213-321.

Impressions vs. intraoral scan:

cost• Impression

materials:

$15-$20

• Stock trays:

$1 to $3

• Model stone:

$2

• Lab fee to pour cast:

$5

• Intraoral scanner:

$10,000 to $45,000

• License fee: $1,000

to $5,000 per year

• Radid prototype or

3D milled models:

$5 to $10



Convenience and comfort:

impression

• Tray selection

• Impression materials can be messy

• Set time from 2-5 minutes

• Problematic with gaggers

• Separate occlusal record material

• Missed margins cannot be corrected

• Positive pressure can capture

obscure margins


intraoral scan• No material mess

(unless using Ti oxide spray)

• Scan time 1-5 minutes

• Gagging rarely a problem

• Occlusion easily scanned

• Articulation?

• Missed margins easily “patched”

• Scanner only captures margins it can

“see”


intraoral scan• Retraction more critical

• Clearance can be digitally checked

• Some offer shade matching capabilities

• Convergence/undercuts digitally examined

• Expedited delivery to lab

• Instant lab feedback



Intraoral scanner accuracy

• 10 impressions of single central

incisor on typodont with PVS

• 10 with Lava COS and iTero

• Average gap for conventional

impression, 112 microns

• Lava COS and iTero, 90 microns

Abdel-Azim T, et al. Comparison of the marginal fit of lithium

disilicate crowns fabricated with CAD/CAM technology by

using conventional impressions and two intraoral digital

scanners. J Prosthet Dent 2015;114:554-559.


• Polyether, vinylsiloxanether, direct

scannable vinylsiloxanetyher and

irreversible hydrocolloid tested on full-

arch reference model

• Conventional impressions showed high

accuracy except polyether and alginate

• Digital impression, Cerec Bluecam,

Omnicam, iTero and Lava COS, higher

deviations


• Digital impressions do not show

superior accuracy compared to

highly accurate conventional

impressions techniques for full-arch

• However, they provide excellent

clinical results within their limitations

Ender A, Mehl A. In-vitro evaluation of the accuracy of

conventional and digital methods of obtaining full-arch dental

impressions. Quintessence Int 2015;46:9-17



Intraoral scanner accuracy• Full-arch impression using Identium,

Impregum and alginate

• Trios color 42.9µ<TRIOS 47.5µ<Cerec

Omnicam 48.6µ<Cerec Bluecam 56.4µ<3M

True Definition 59.7µ<iTero 68.1µ<3M Lava

COS 82.8µ

• Precision of complete arch scans approaches

or exceeds some conventional systems

Ender A, Attin T, Mehl A. In vivo precision of conventional and

digital methods of obtaining complete-arch dental impressions.

J Prosthet Dent 2016;115:313-320.

Conclusions: Crowns

• Establish or reestablish optimal smile line

esthetics

• Apply principles of esthetics including tooth

color, proportion, gingival architecture

• Waxing followed by provisional restoration is

the esthetic template

Conclusion: Crowns (cont’d)

• Maintain soft tissue health throughout

treatment

• Digitally communicate with (scripted images)

and remain involved with the lab

• New ceramics offer significant esthetic and

functional advantages

• Digital dentistry and intraoral scanning is

becoming the new reality



Agenda

• Esthetics and ceramic veneers

Veneer longevity

• Beier et al. Int J Prosthodont 2012

• Sadowsky S. J Pros Dent 2007

• Layton D, Walton T. Int J

Prosthodont 2013

• Fradeani et al. Int J Periodontics

Restorative Dent 2005

• Petridis HP, et al. European J

Esthet Dent 2012

Conventional Preparation Design

• Gingival and proximal chamfer

• Incisal wrap-over with chamfer

• Maintain proximal contact areas

• Gingival proximal “elbow”



Contemporary veneer technique

• Gingival chamfer only

• Prepare thorough proximal areas in

selected teeth

• No gingival elbow

• Incisal butt joint

• Rounded line angles

Priest GF. Benefits of proximal extensions for ceramic veneer

preparations. Pract Proced & Aesthet Dent 2004;16:265-272.

Facial reduction

Chamfer in

gingival aspect

only

Incisal reduction



Spear FM. Esthetic correction of anterior dental

misalignments: conventional versus instant

(restorative) orthodontics. J Esthet Restorative

Dent 2004;16(3):149-164.

Overriding principle of “instant

orthodontics” is:Will the tooth or teeth

require restoration even if orthodontic

treatment is initiated?



Posterior tooth display

• Premolars were partially visible in more

than 80% of smiles and displayed more

than 65% of their crown length during

smiling.

• Gingival display was greater for

premolars than for central incisors

Kapagiannidis D, Kontonasaki E, Bikos P, Koidis P. Teeth and

gingival display in the premolar area during smiling in relation

to gender and age. J Oral Rehabilitation 2005;32(11):830-837.

Gummy Smile

• One of most frequent causes of

gummy smile is altered eruption

• High smile lines in 29% of people

• APE (altered passive eruption)

determined by failure of passive

dental eruption, giving rise to

excessive gingival overlap on

anatomical crown

Gummy Smile• AAE (altered active eruption) primary

failure of active dental eruption

phase, which results in tooth failing

to emerge sufficiently from alveolar

bone.

• APE may not need surgical guide

whereas AAE may

Verdi S, et al. Gummy smile and short tooth syndrome – part 2:

periodontal surgical approaches in interdisciplinary treatment.

Compendium 2016;37:247-252.



Envision the end result

• Waxing of size and proportions

duplicated in stone

• If significant contour changes,

vacuum matrix made on cast to

serve as preparation guide

• PVS putty matrix for provisional

restorations

• Shade selection prior to anesthesia

Clear matrix from waxing vs.

composite resin mock-up

• Mock-up is labor intensive

• Veneers may be bonded to composite

resin

• Preparation depth easily gauged using

clear matrix

• Matrix does not capture sufficient

detail for making provisional

restoration

Tapered burs automatically

reduce less gingivally and

more incisally



Veneer preparation

Coarse burs

• Komet

TurboDiamond:

T5856 018 and 016.

• Komet

TurboDiamond:

T5878 014

Finishing burs

• Komet Finishing

8856: 018, 016, 012

Finishing strips for

smoothing and

rounding margins

Depth cutting burs

not recommended

• Leave rougher surface

• Teeth require different depths of

preparation– Older worn teeth versus younger intact teeth

– Alteration of contours: overpreparation in some

areas and underpreparation in others

Depth of preparation

• NYU, 580 veneers in 66 patients followed

up to 12 years

• 42 veneers failed (7.2%)

• Veneers with margins in dentin 10x more

likely to fail than those bonded to enamel

• Survival rate of 99% for veneers confined to

enamel and 94% with enamel only at

margins

Gurel G, et al. Influence of enamel preservation on failure rates

of porcelain laminate veneers. Int J Periodontics Restorative

Dent 2013;33:31-39.



Depth of preparation

• 80 extracted teeth in 8 groups

• All-ceramic crown prep for mandibular

central had highest reduction (65%),

lowest was ceramic veneer for maxillary

central (30%)

• Veneers offer significant advantage over

complete coverage preps

Al-Fouzan AF, Tashkandi DA. Volumetric measurements of

removed tooth structure associated with various preparation

designs. Int J Prosthodont 2013;26:545-548.

Veneer preparation• Single operator prepared 3 groups of 5 maxillary

central incisors to a depth of 0.5 mm using dimple,

depth-groove and freehand methods of

preparation. No significant difference between the

3 techniques in conserving enamel

• Neither the use of a custom-depth orientation bur

nor a sectioned index necessarily eliminates the

subjectivity involved in the tooth preparation any

better than the techniques used in this study

Cherukara GP, Davis GR, Seynmour K, Zou L,

Samarawickrama DYD. Dentin exposure in tooth preparations

for porcelain veneers: A pilot study. J Prosthet Dent

2006;94(5):414-420.

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