update in direct restoratives
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Faculty of Dentistry
National University of SingaporeFounded 1905
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.
Faculty of Dentistry
National University of SingaporeFounded 1905
“ Dentists spend approximately 70% of their time replacing restorations ”
Minimal intervention dentistry: a review.
FDI Commission Project. Tyas et al 2000
Faculty of Dentistry
National University of SingaporeFounded 1905
DENTAL AMALGAM• bonded vs non bonded AR• longevity of AR
cavity size operator experience
• comparison with PCR• issue of mercury toxicity
Faculty of Dentistry
National University of SingaporeFounded 1905
Bonded vs nonbonded AR
• Longevity bonded AR > nonbonded AR
?
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
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. ”
Faculty of Dentistry
National University of SingaporeFounded 1905
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 …………….
Faculty of Dentistry
National University of SingaporeFounded 1905
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 ”
Faculty of Dentistry
National University of SingaporeFounded 1905
2006
• “ ……….amalgam should remain a viable dental restorative option for children ”
Journal of the American Medical Association
Environmental Health Perspectives
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
2009
• classified encapsulated dental amalgam as a class II medical device
• “ …..the material is a safe and effective restorative option for patients ”
FDA, US
Faculty of Dentistry
National University of SingaporeFounded 1905
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 ….”
Faculty of Dentistry
National University of SingaporeFounded 1905
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. ”
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
The World Alliance for Mercury-Free Dentistry called for phasing out dental amalgam by 2025 and by 2018 for baby teeth.
Faculty of Dentistry
National University of SingaporeFounded 1905
“ 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
Faculty of Dentistry
National University of SingaporeFounded 1905
Faculty of Dentistry
National University of SingaporeFounded 1905
classical classical
GI – RESIN HYBRIDS
RMGIC
PM COMP RESIN
Glass Ionomer Cements Composite Resins
Faculty of Dentistry
National University of SingaporeFounded 1905
GIC
Resin Modified GIC Antonucci et al 1988, Mitra
1988
GIC + monomers + photoinitiators
Faculty of Dentistry
National University of SingaporeFounded 1905
Issues - RMGIC
• retention • margins• wear, loss of anatomic form• colour change• fluoride leaching
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
anatomic form and wear
• occurs in the mid- to long term
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
colour stability
initial colour may be acceptable but changes over time
Faculty of Dentistry
National University of SingaporeFounded 1905
classical classical
GI – RESIN HYBRIDS
RMGIC
PM COMP RESIN
Glass Ionomer Cements Composite Resins
Faculty of Dentistry
National University of SingaporeFounded 1905
Composite Resins
Developments of CR materials bonding systems light systems
Faculty of Dentistry
National University of SingaporeFounded 1905
Material what’s new ??
• monomer /matrix• filler
Faculty of Dentistry
National University of SingaporeFounded 1905
Monomers
traditionally bis-GMA ( Bowen 1960 ) + TEGDMA
UDMA ( Foster and Walker 1974 ) and modified UDMA
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
Microhybrid and nanohybrid CR
improved strength, handling & polishability Ritter 2005
Watanabe et al 2008
reduced wear
Yap et al 2004
Yesil et al 2008
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
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.
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
Resin infiltration• Indications
non-cavitated enamel and outer 1/3 of dentine
• Contra-indications cavitated lesions root caries pit and fissure caries erosion lesions
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
Faculty of Dentistry
National University of SingaporeFounded 1905
Dentine Bonding System
• ETCHANT
• PRIMER
• ADHESIVE
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
Self – Etch Adhesives
do not require a separate etching step contain acid monomers to
‘etch/condition’ & ‘prime’ at the same time
Faculty of Dentistry
National University of SingaporeFounded 1905
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)
Faculty of Dentistry
National University of SingaporeFounded 1905
Acid Monomers
• Acids may be strong ( pH < 2 ) good for enamel bonding but poor
dentine bonding
• Optibond XTR ( Kerr ), Simplicity (Apex)
Faculty of Dentistry
National University of SingaporeFounded 1905
Self – Etch Adhesives
lower incidence of post-op sensitivityPerdiago et al
2003
Unemori et al 2004
Tay et al 2002
Faculty of Dentistry
National University of SingaporeFounded 1905
• 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
Faculty of Dentistry
National University of SingaporeFounded 1905
2-step
• inability to be self cured• requires a self cure catalyst
activator for self cure /dual cure cements for indirect procedures
Faculty of Dentistry
National University of SingaporeFounded 1905
Summary for SE systems
• use of etchant for ‘mild’ acid systems • inability to be self cured
Faculty of Dentistry
National University of SingaporeFounded 1905
Self – Etch Adhesives
• 2 – step ( Etchant + Primer, Adhesive )• 1 – step ( Etchant + Primer + Adhesive )
two - component ( require mixing ) one - component ( no mixing )
Faculty of Dentistry
National University of SingaporeFounded 1905
one – component SE• ‘ all – in – one ’ adhesive
• conditioning + priming + adhesive
• do not require mixing
Faculty of Dentistry
National University of SingaporeFounded 1905
1 step SE adhesives
• user friendly• low bond strengths
Inoue et al 2001, 2003
Bouillaguet et al 2001 Fritz & Finger 1999
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
1 step SE adhesives
• increase permeability • less mechanical durability• chemical instability • require a self-cure activator for indirect
procedures
Faculty of Dentistry
National University of SingaporeFounded 1905
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.
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
Problems with new dentine adhesives
• in-vitro data = clinical data ??• clinical validation ( if any ) :
short term• quick turnover of products
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
Summary on DBS
3 – step etch & rinse adhesives still perform best in laboratory and clinical research
Sunnegardh & van Dijken 2000van Dijken 2000, 2001
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
The Era of Light Polymerization
• control of working time• sets in seconds • colour stability • posterior restorations effectively done
Faculty of Dentistry
National University of SingaporeFounded 1905
Type of curing light
• traditional halogen light• plasma arc• argon laser• lead emitting diode ( LED )
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
Which lights cure all CR
?
Faculty of Dentistry
National University of SingaporeFounded 1905
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)
Faculty of Dentistry
National University of SingaporeFounded 1905
Polymerization of Composite Resins
Initiators camphorquinone ( CQ ) PPD ( phenylpropandione ) lucerin
• radiation absorption spectrum = lamp emission spectrum
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
How long to cure
?
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
Best Mode of Cure
?
Faculty of Dentistry
National University of SingaporeFounded 1905
• 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
Faculty of Dentistry
National University of SingaporeFounded 1905
“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
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
.
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
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
heat generation with high-power photopolymerization units should not be underestimated as a biological problem for both gingival and pulpal tissues
Summary statements
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
Practice Based Research Network
• 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
Faculty of Dentistry
National University of SingaporeFounded 1905
• 12-year survival rate : large amalgams = large composites
( high caries risk group ) large composites > large amalgams ( low caries risk group )
Practice Based Research Network
Faculty of Dentistry
National University of SingaporeFounded 1905
Safety of CR - BPA• Bisphenol A ( BPA ) found
in plastic productsdental sealantscomposite resins ??
• safety issuesestrogenic effectsaffecting reproduction and
development
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
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.”
Faculty of Dentistry
National University of SingaporeFounded 1905
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. ”
Faculty of Dentistry
National University of SingaporeFounded 1905
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. ”
Faculty of Dentistry
National University of SingaporeFounded 1905
PREVENTION
remineralization fluoride minimal intervention repair of defective restorations patient education
Faculty of Dentistry
National University of SingaporeFounded 1905
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
Faculty of Dentistry
National University of SingaporeFounded 1905
Avoid
Death spiral of restorations
Qvist 2008
Faculty of Dentistry
National University of SingaporeFounded 1905
Possible risks of replacement
Surface area increases Millar et al 1992
(CR)Brantley et al 1995Hunter et al 1995 ( CR and AR)
Faculty of Dentistry
National University of SingaporeFounded 1905
Possible risks of replacement
• 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
Faculty of Dentistry
National University of SingaporeFounded 1905
Possible risks of replacement
• destruction of tissue• possibility of endodontic therapy• cost • time
Faculty of Dentistry
National University of SingaporeFounded 1905
“ 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
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