update in direct restoratives

Faculty of Dentistry

National University of SingaporeFounded 1905



Caries incidence globally

• Dental caries is still a major public health problem to most countries of the world

Petersen, Baez, Kwan & Ogawa 2009Future Use of Materials for Dental RestorationReport of the meeting convened at WHO HQ,

Geneva, Switzerland.



“ Dentists spend approximately 70% of their time replacing restorations ”

Minimal intervention dentistry: a review.

FDI Commission Project. Tyas et al 2000



DENTAL AMALGAM• bonded vs non bonded AR• longevity of AR

cavity size operator experience

• comparison with PCR• issue of mercury toxicity



Bonded vs nonbonded AR

• Longevity bonded AR > nonbonded AR

?



Adhesively bonded versus non-bonded amalgam restorations for

dental caries• randomized clinical trials • split mouth or paired tooth• Class I, II, or V restorations • with any adhesive• minimum follow up of 2 years

Fedorowicz et al, Cochrane Database Syst Rev 2009 ; CD007517



Adhesively bonded versus non-bonded amalgam restorations for

dental caries• “ …no evidence to show a difference in

amalgam restoration survival on the basis of whether the restoration was adhesively bonded or not.”

Fedorowicz et al, Cochrane Database Syst Rev 2009 ; CD007517



How long do direct restorations placed within the general dental services in

England and Wales survive ?• 80 000 subjects, 503 965 restorations• 11-year duration• AR mainly for posterior load bearing CR for Class III and IV GIC for Class V

Burke & Lucarotti 2009, 206:E2, discussion 26-7



How long do direct restorations placed within the general dental services in

England and Wales survive ?

• small AR showed the best 10-year survival rates ( 58%)• large MOD AR showed poorer 10-year survival rates ( 43%

)• pin placement associated with reduced survival time• CR including incisal angle – reduced survival by 2 years• GIC – 10-yr survival rate of 38%

Burke & Lucarotti 2009, 206:E2, discussion 26-7



Longevity of restorations• AR – 16 years irregardless of restoration

classification • CR – 6 years with Class 2 showing lowest longevity • High caries risk – reduced CR longevity compared

to low or moderate caries

Sunnegardh-Gronberg et al 2009



Longevity of restorations

• Operator experience dentists with 15 or more years of experience

provided restorations with > longevity for both AR and CR

Sunnegardh-Gronberg et al 2009



1997 Consensus Statement on Dental Amalgam

• ‘ No controlled studies have been published demonstrating systemic adverse effects from amalgam restorations ”

• ‘ .... the small amount of mercury released from amalgam restorations, especially during placement and removal, has not been shown to cause any …adverse health effects. ’FDI World Dental Federation & WHO



1998 • Major review of the literature

“ based on available scientific information, amalgam continues to be a safe and effective restorative material “

“ there currently appears to be no justification for discontinuing the use of dental amalgam ”

ADA’s Council on Scientific Affairs



2004

• Expert panel reviewed literature from 1996 – 2003

• “ the current data are insufficient to support an association between mercury release from dental amalgam and various complaints that have been attributed to this restorative material. ”



2006• 2 independent clinical trials • “ there were no statistically significant

differences in adverse neuropsychological or renal effects observed over the 5-year period in children whose caries are restored using dental amalgam or composite materials …………….



2006• ………. “ children ………..did not, on

average, have statistically significant differences in neurobehavioral assessments in nerve conduction velocity when compared with children who received resin composite materials or amalgam ”



2006

• “ ……….amalgam should remain a viable dental restorative option for children ”

Journal of the American Medical Association

Environmental Health Perspectives



Environmental concerns“ If environmental contamination by

mercury containing waste from dental practices is not cut down to very low levels, then it is likely to be the main reason for government action against the use of amalgam in the future ”

Eley 1997



2008

• “ …dental amalgams are effective and safe, both for patients and dental personnel and also noted that alternative materials are not without clinical limitations and toxicological hazards ”

Scientific Committee of the European Commission



2009

• Literature review from 2004 – 2009• “ the scientific evidence supports the

position that amalgam is a valuable, viable and safe choice for dental patients ”

ADA Council on Scientific Affairs



2009

• classified encapsulated dental amalgam as a class II medical device

• “ …..the material is a safe and effective restorative option for patients ”

FDA, US



2009 “ …dental amalgam remains a dental

restorative material of choice, in the absence of an ideal alternative and lack of evidence of alternatives as a better practice. If dental amalgam were to be banned, a better and more long-lasting replacement would be needed than the materials available to date ….”



2009“ …. while the harmful effects of mercury on

health and the environment are recognized, the possible adverse effects of alternative materials require further research and monitoring. Providing the best care possible to meet patients’ needs should be of paramount importance. ”



2009

“… complete ban may not be realistic, practical and achievable. It may be prudent to consider ‘phasing down’ instead of ‘phasing out’ of dental amalgam at this stage ”

Future use of materials for dental restorationReport of the meeting convened at WHO HQ, Geneva, Switzerland. 2009



Ethical issues

• correlate amalgams to adverse health symptoms/disease

• removal of amalgams to provide placebo effect

• removal of amalgams at patient’s request• amalgam - free practice



Minimata Convention on Mercury Treaty

........treaty to rein in the use and emission of health-hazardous mercury

amid pressure from dentist groups, the treaty also did not provide a cut-off date for the use of dental fillings using mercury amalgam, but did agree that the product should be phased down.

UN Environmental Program ( UNEP)

Geneva , 19th Jan 2013



The World Alliance for Mercury-Free Dentistry called for phasing out dental amalgam by 2025 and by 2018 for baby teeth.



“ majority of patients prefer a tooth – coloured material ( composite ), even when informed that the clinical longevity will be shorter than that of amalgam ”

Espelid et al 2006



classical classical

GI – RESIN HYBRIDS

RMGIC

PM COMP RESIN

Glass Ionomer Cements Composite Resins



GIC

Resin Modified GIC Antonucci et al 1988, Mitra

1988

GIC + monomers + photoinitiators



Issues - RMGIC

• retention • margins• wear, loss of anatomic form• colour change• fluoride leaching



RMGIC

• Clinical evaluations of resin-modified glass-ionomer cements

Sidhu, Dent Mater, 2010 , 26 (1) : 7-12

• Clinical performance of cervical restorations—A meta-analysis

Heintze et al, Dent Mater, 2010, 26 ( ) : 993-1000



Retention

• retention rate range from 87.5% - 100%

• 2-step SE > 3-step E & R > GIC > RMGIC > 2-step E & R > PMCR > 1-step SE



anatomic form and wear

• occurs in the mid- to long term



secondary caries

• No secondary caries was found in carious and non carious cavities

for up to 5 years.Neo et al 1996Abdalla et al 1997van Dijken et al 1999Folwaczmy et al 2001Loguercio et al 2003



Caries preventive effect of GIC and RMGIC

• 4 out of 220 studies• RMGIC restorations remain as free of

recurrent caries as did conventional GIC restorations Mickenautsch et al. Absence of carious lesions at margins of GIC and resin-modified GIC restorations. A systematic review . Eur J Prosthodont Rest Dent 2010:18:139-145



colour stability

initial colour may be acceptable but changes over time



classical classical

GI – RESIN HYBRIDS

RMGIC

PM COMP RESIN

Glass Ionomer Cements Composite Resins



Composite Resins

Developments of CR materials bonding systems light systems



Material what’s new ??

• monomer /matrix• filler



Monomers

traditionally bis-GMA ( Bowen 1960 ) + TEGDMA

UDMA ( Foster and Walker 1974 ) and modified UDMA



NEW - monomers reduce polymerization shrinkage/stress

Siloranes Weinmann et al 2005

modified UDMA – increased molecular weight eg Kalore ( GC ), Venus ( Kulzer)

N’Durance ( Septodent ) Ormocers eg Definite ( Degussa )

Wolter et al 1994



Microhybrid and nanohybrid CR

improved strength, handling & polishability Ritter 2005

Watanabe et al 2008

reduced wear

Yap et al 2004

Yesil et al 2008



NEW – modify fillers

Add polymer nonofibers, glass fibres, fused silica fibres

and titania nanoparticles dicalcium/tetracalcium phosphate nanoparticles antibacterial and remineralising agents eg fluoride, chlorhexidine, zinc oxide or quaternary ammmonium polyethyleneimine

nanoparticles, MDPM monomer



NEW

• Nanocomposites incorporate calcium fluoride nanoparticles into

dental resins high levels of calcium phosphate and fluoride release

achievable at low filler particle levels due to high surface areas of nanoparticles

addition of nanoparticles do not affect mechanical properties of resin

Xu et al 2010



Bulk fill CR

• high depth of cure (4-5 mm)• reduce incremental placement

less porosities less time

• use below the restoration (flowable) or as a restorative (sculptable) material



Bulk Fill CR• Flowables

Surefil SDR Flow DentsplyX-tra Base VocoVenus Bulk Fill Heraeus KulzerFiltek Bulk Fill 3M ESPE

• Sculptables Tetric N-Ceram Bulk Fill Ivoclar/VivadentX-tra Fil VocoQuiXfil DentsplySonicFill Kerr



How did we achieve the reduction in polymerization

stress?ANSWER:

• The kinetics of the radical polymerization is regulated

• As the modulus development is slower less polymerization stress builds up.

• Call it a chemical soft start polymerization if you like.



Perfect Compatibility with metharylate-based bonding and capping composites

Any (!) cap composite*

SDR™

SDR™ Filling Technique

* EsthetX HD, CeramX, Spectrum TPH 3, Filtek Supreme, Tetric EvoCeram, Artemis, Z100, Point4, Venus, Enamel HFO, Herculite, Premise, etc ... but not Filtek Silorane



Bulk Fill CR• Flowables

Surefil SDR Flow DentsplyX-tra Base VocoVenus Bulk Fill Heraeus KulzerFiltek Bulk Fill 3M ESPE

• Sculptables Tetric N-Ceram Bulk Fill Ivoclar/VivadentX-tra Fil VocoQuiXfil DentsplySonicFill Kerr



Clinical Study Burgess & Munoz

• 3 year study • 170 Cl 1 and Cl 2 in 2 schools• 86 restorations at the end of 3 years • 6 fractures within capping agent and one

restoration replaced• no post-op sensitivity, no recurrent caries



NEW – resin infiltration• use of infiltrative resin to arrest superficial carious lesions proximally• soak up the porous lesion body with a low viscosity resin and polymerized • block diffusion pathways for cariogenic acids and seal lesions• diffusion barrier created inside lesion

Paris & Meyer-Lueckel 2007



Resin infiltration• Indications

non-cavitated enamel and outer 1/3 of dentine

• Contra-indications cavitated lesions root caries pit and fissure caries erosion lesions



Methodology for resin infiltration

15% HCl etching gel – 120 sec wash off with air-water-spray – 30 sec blow dry – 10 sec apply ethanol – 10 sec blow dry – 10 sec apply infiltrant – 5 mins, blow dry and floss light cure from buccal, occlusal and lingual – 1 min repeat infiltration step – 1 min

Paris & Meyer-Lueckel 2010



Clinical Studies for resin infiltration

• Ekstrand et al 2010 - combination of resin infiltration and fluoride varnish increased therapeutic effect > 35% compared to fluoride varnish alone

• Paris et al 2010 - Caries progression was seen in 7% of the effect group and in 37% of the control group



Take Home Messages CR Material

• development of nanocomposites has led to significant improvements in dental materials and clinical applications

• still room for improvement for nanocomposites

Chen 2010



Dentine Bonding System

• ETCHANT

• PRIMER

• ADHESIVE



Adhesion Strategies

• concept of exchanging inorganic tooth material for synthetic resin

• done in 1 , 2 or 3 application steps • classified as

Etch - & - rinse ( E & R ) Self - etch ( SEA ) ( RM ) GIC



Self – Etch Adhesives

do not require a separate etching step contain acid monomers to

‘etch/condition’ & ‘prime’ at the same time



Acid monomers

• Acids may be ‘mild’ ( pH > 2.0 ) dentine smear layer is usually alteredsclerotic and tertiary dentine , enamel not

effectively etched

• Unifil Bond (GC), Clearfil SE Bond (Kuraray), S/E Optibond Solo Plus (Kerr)



Acid Monomers

• Acids may be strong ( pH < 2 ) good for enamel bonding but poor

dentine bonding

• Optibond XTR ( Kerr ), Simplicity (Apex)




lower incidence of post-op sensitivityPerdiago et al

2003

Unemori et al 2004

Tay et al 2002



• etching and priming occurs to the same depth of penetration

• no guesswork with ‘how wet is wet’• less aggressive and more superficial

interaction with dentine , tubules largely obstructed with smear layer which is altered and infiltrated by primer



2-step

• inability to be self cured• requires a self cure catalyst

activator for self cure /dual cure cements for indirect procedures



Summary for SE systems

• use of etchant for ‘mild’ acid systems • inability to be self cured




• 2 – step ( Etchant + Primer, Adhesive )• 1 – step ( Etchant + Primer + Adhesive )

two - component ( require mixing ) one - component ( no mixing )



one – component SE• ‘ all – in – one ’ adhesive

• conditioning + priming + adhesive

• do not require mixing



1 step SE adhesives

• user friendly• low bond strengths

Inoue et al 2001, 2003

Bouillaguet et al 2001 Fritz & Finger 1999



1 step SE adhesives

• simplify steps• time saving• make them more user-friendly• at the expense of quality or durability

of resin bonds ?Tay 2002



1 step SE adhesives

• increase permeability • less mechanical durability• chemical instability • require a self-cure activator for indirect

procedures



Degradation of dentine adhesives

deterioration in the strength and structural integrity of resin-dentine bonds created with total-etch (Armstrong et

al 2004, Carrilho et al 2007 ) and self-etch ( Sano

et al 1999, Hashimoto et al 2000 ) techniques over time.



Problems with current adhesive systems

• earlier systems were too hydrophobic and recent adhesives tend to be overly hydrophilic, impairing adhesion

• increasing acidity of adhesive systems• mixing of hydrophilic and hydrophobic

components in 1 system



complex mixture of hydrophobic and hydrophilic components in an organic solvent ( acetone or ethanol )

phase separation in one-component HEMA – free SE adhesive

Van Landuyt et al 2005

shelf life problems a reduced bond strength

Van Landuyt et al 2009 Sadek et al 2005

1 step SE adhesives



Problems with new dentine adhesives

• in-vitro data = clinical data ??• clinical validation ( if any ) :

short term• quick turnover of products



Summary on DBS

“ None of today’s systems yet appears able to guarantee leakage-free margins for a significant amount of time, especially at the dentine site ”

Van Meerbeek et al 1998De Munck et al 2003



Summary on DBS

3 – step etch & rinse adhesives still perform best in laboratory and clinical research

Sunnegardh & van Dijken 2000van Dijken 2000, 2001



A critical review of the durability of adhesion to tooth

tissue

• 3-step E & R adhesives remain the “gold standard ” in terms of durability

• 2-step self - etch adhesive approach the gold standard

Munck et al 2005



Dental Adhesives

• In vitro studyBond strength of 11 adhesives to dentine

• The 3-step total etch system had the highest bond strength > 2 step SE > 1-step SE

Sarr et al 2010



Take Home Message Bonding Systems

• In vivo bonding to enamel when the substrate is etched with phosphoric acid for 30 seconds is adequate and reliable

• Dentine quality of bond is related to many variables formation of hybrid layer is mandatory not totally eliminated leakage bond failures still a problem

Ferrari and Garcia-Godoy 2002



SUMMARY on Bonding Systems

Etch and Rinse systems ..… perform better on enamel than Self-Etching systems which may be more suitable for bonding to dentin.

Milia et al 2012



The Era of Light Polymerization

• control of working time• sets in seconds • colour stability • posterior restorations effectively done



Type of curing light

• traditional halogen light• plasma arc• argon laser• lead emitting diode ( LED )



Light-Emitting Diodes (LED)• Semiconductors

electrically-excited atoms • Gallium-nitride blue• Narrow emission spectrum

430-490 nm* peak at 470 nm* near absorption max

of camphorquinone* efficient



LED Curing Lights• Long lasting light source

minimal agingminimal decrease in output

• Less lateral heat production* Fanned

larger size; continual operation; slight noise* Fan-less

smaller size; quiet; easier infection control; portability may shut down temporarily with continual use

thermostat

• No filters• Typically cordless

Duke, Compend Contin Educ Dent 2001



Which lights cure all CR

?



Requirements for curing

• Wavelength to match resin photoinitiator

CQ photo initiator: 430-480 nm Proprietary: 380 – 480nm (broad spectra)

• Enough power to cure resin> 800mW / cm2 for regular curing (20 seconds) > 1500mW / cm2 for fast curing (5 seconds)



Polymerization of Composite Resins

Initiators camphorquinone ( CQ ) PPD ( phenylpropandione ) lucerin

• radiation absorption spectrum = lamp emission spectrum



LED Curing Lights• First Generation

high cost > arrays was better < 300 mW/cm2

did not cure all CR

• Second Generation use of chips > output power improved battery ( NiMH Energy ) did not cure all CR

• Third Generation broad band / multi spectrum



How long to cure

?



Depth of cure

For halogen

At 3 mm layers, even at 800 mW/cm2 and 80 secs exposure, there was no adequate polymerization

Rueggeberg et al 1994



Depth of cure With LED ( 1500 – 2000 mW/cm2 )

Curing time for 2 mm of CR can be reduced to 20 sec

Ernst et al 2004

Schattenberg et al 2008Kramer 2008

Rueggeberg et al 2009



Best Mode of Cure

?



• Slow increase or delay in irradianceStepped

short, low initial burstfull intensity

Rampedgradual increase

from initial low level

Pulsed delayedshort, low level burstdelay for polishingfull intensity

• Slow rate of shrinkage reducing stress

“Soft-Start” Polymerization



“Soft-Start” Studies• Laboratory studies somewhat equivocal

many show benefitsome show no improvement

• Clinical studies are limitedall show NO BENEFIT!

* El Mahdy, J Dent Res 1999 * Oberlander, Clin Oral Investig 1999* Brackett, Oper Dent 2002



Heat generation

• problem when dentine is < 1 mm – rise of 5.60C

• lower heat generation with LED ?93 % of total energy is still heat as intensity is

up to 2,000 mW/cm2

Asmussen & Peutzfeldt 2005



Name of light Type Company Power density (mW/cm2)

Astralis 10 QTH Ivoclar/Vivadent 1200

Expt 1 LED Ivoclar/Vivadent 1600

Bluephase 16i LED Ivoclar/Vivadent 2000

Expt 2 LED Ivoclar/Vivadent 3000

Park et al 2010

Curing lights – heat generation



Curing lights – heat generation

• “ …exposure times with high intensity lights ( > 1200 mW/cm2 ) should be limited to short periods ( 15 secs ) to minimize potential biologic impact ”

Park et al 2010



.

with high-power LED units of the latest generation, curing time of 2 mm thick increments of resin composite can be reduced to 20 seconds to obtain durable results

Summary statements



Summary statements

polymerization kinetics can be modified for better marginal adaptation by soft-start polymerization; however, in the majority of cavities this may not be the case



heat generation with high-power photopolymerization units should not be underestimated as a biological problem for both gingival and pulpal tissues

Summary statements



Light curing • cure in layers of

max 2 mm• keep tip close to

restoration• impossible to

“overcure”• maintain light

tip and output

Take home message



Take home message LED will be the light source for the next

generation curing light emits enough power for fast and adequate curing correct wavelength extended LED life slow degradation portability

heat management needs to be looked into



Practice Based Research Network

• large Cl 2 CR and amalgams ( 3, 4, 5-surface restorations )• restorations placed from 1983 – 2003,

min 5-year followup• 1949 Cl 2 in 273 patients

Opdam et al 2010




• Restorations placed in the high caries risk group lower survival than restorations placed in the low caries risk group

• Large CR > 12-year survival than large AROpdam et al 2010



• 12-year survival rate : large amalgams = large composites

( high caries risk group ) large composites > large amalgams ( low caries risk group )




Safety of CR - BPA• Bisphenol A ( BPA ) found

in plastic productsdental sealantscomposite resins ??

• safety issuesestrogenic effectsaffecting reproduction and

development



BPA• direct ingredient - rarely used as an ingredient

in dental products• by-product of other ingredients in CR or

sealants - CR formulated from bisGMA, bis-DMA can release very small quantities of BPA due to salivary enzymes acting on it

• trace material – bisGMA formulated from BPA as a starting ingredient



US Dept of Health and Human Services

2007“ Dental sealant exposure to BPA occurs

primarily with use of dental sealants. This exposure is considered an acute and infrequent event with little relevance to estimating general population exposures.”



FDA 2010 “ recent studies provide reason for some

concern about the potential effects of BPA on the brain, behaviour and prostate gland of fetuses, infants and children……., based on this conclusion, the FDA does not require testing of dental materials, medical devices or food packaging for BPA at this time. ”



ADA 2010

“ Based on current research, the Association agrees with the authoritative government agencies that the low-level of BPA exposure that may result from dental sealants and composites poses no known health threat. ”



PREVENTION

remineralization fluoride minimal intervention repair of defective restorations patient education



Minimally Invasive Dentistry

“ ……loss of even a part of a human tooth should be regarded as a serious injury, never to be considered lightly, and the tooth is certainly worthy of the most careful restoration ”

Markley 1951



Avoid

Death spiral of restorations

Qvist 2008



Possible risks of replacement

Surface area increases Millar et al 1992

(CR)Brantley et al 1995Hunter et al 1995 ( CR and AR)




• damage to adjacent teeth• 69% of adjacent permanent teeth• most common : depth of 0.5 – 1.0 mm

scratches and grooves• restorations placed in 35% of these

teeth after 1- 3.5 years Qvist et al 1992




• destruction of tissue• possibility of endodontic therapy• cost • time



“ The day is surely coming.... when we will be engaged in practicing preventive, ratherthan reparative, dentistry. When we will so understand the etiology and pathology ofdental cavities that we will be able to combat its destructive effects by systemicmedication.”

Dr. G. V. Black 1896

update in direct restoratives

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