Operative Lec
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Recommended Reading List • New developments in dental adhesion. Perdigao, J. Dental Clinics of North America. 51(2):333-57, viii, 2007 Apr. • A critical review of the durability of adhesion to tooth tissue: methods and results results. De Munck, Munck J. J et al. al Journal of Dental Research. 84(2):118-32, 2005 Feb. • Dental adhesives of the future. Tay, F. R. Pashley, D. H. Journal of Adhesive Dentistry. 4(2):91-103, 2002. • Future directions in bonding resins to the dentine-pulp complex. Bouillaguet, S.Wataha, J. C. Journal of Oral Rehabilitation. 31(4):385-92, 2004 Apr.
Dental Bonding Oper 5001 Dr. Daniel C. N. Chan
Interface 1
DENTAL ADHESION
Adhesive
Steps in Forming Good Adhesion (1) Clean adherend
Adhesive System or Luting Cement
Interface 1
(2) Good wetting
Interface 2
Adherend 1
DENTAL JOINT
Adherend 2
(3) Intimate adaptation
(4) Bonding
ENAMEL, DENTIN > Liner, Base, Cement > Post and Core > Dental Amalgam > Implant >
< Composite, Amalgam < Cast Inlay, Onlay, or Crown < All-Ceramic Inlay, Onlay, or Crown < Veneers, Maryland Bridges < Orthodontic Brackets
(5) Good curing
© 2004, Bayne and Thompson, UNC School of Dentistry.
– + chemical physical mechanical bonding bonding bonding
© 2004, Bayne and Thompson, UNC School of Dentistry.
© 2004, Bayne and Thompson, UNC School of Dentistry.
BOND STRENGTH TESTING What are good bond strengths? 2
1
4 3
Macro SBS
SBS 18-35 MPa (typically ≅ 20 MPa) TBS
10-12 MPa (typically ≅ 10 MPa)
µSBS
40-80 MPa (typically ≅ 60 MPa)
3c 3b
3a 3a 3b
© 2004, Bayne and Thompson, UNC School of Dentistry.
3c
µTBS 40-80 MPa (typically ≅ 60 MPa)
µTBS
1
PERFORMANCE FACTORS 5 Categories of Factors Affecting Performance (1) OPERATOR Technical ability, Age, Eyesight, ...
(2) DESIGN SL, Bevels, Outline Form, ….
Microtensile Bond Strength Testing and Failure Analysis of Hybrid and Flowable Composites Jones, Cindy T./Chan, Daniel C. N./Pashley, David/ Fernando de Goes, Mario/Nelson, Steven K.
(3) MATERIALS Composition, Product age, T, %RH, ...
(4) INTRAORAL LOCATION Anterior-Posterior, Maxillary-Mandibular, Lingual-Facial, Premolar-Molar, Tooth Flexure, ...
(5) PATIENT F-exposure, Diet, Oral Hygiene IQ, Caries Risk, ...
J Adhes Dent 8 (2006), No 1
© 2004, Bayne and Thompson, UNC School of Dentistry.
ENAMEL MICROSTRUCTURE Quick Review DENTIN / SBMP / Z100
1. 2. 3.
Conditioning Priming Bonding
.
0
10
30
40
Shear Bond Strength (MPa + s.d.) © 2004, Bayne and Thompson, UNC School of Dentistry.
ENAMEL BONDING SYSTEMS 89v/o HA, 6% Organic, 5% Water
FROSTY APPEARANCE
Advantages of enamel etching increases surface area increase wettability increase retention decrease marginal leakage and stain
SBS = 20 MPa
2
Enamel surface morphology Featureless Types 1, 2 and 3 Cli i l Clinical significance: i ifi prismless deciduous & aprismatic cervical enamel
Ideal dentin bonding agent biocompatible bond instantly retentive to dentin bond strength > polymerization shrinkage bond strength > thermal expansion does not hydrolysis
Advantages of enamel etching
Compositon of Enamel and Dentin by Weight and Volume 100 90 80 70 60 50 40 30 20 10 0
95 86 70 50
18 12
12
Dentin Wt %
Enamel Vol %
4 1 Enamel Wt %
2525
Inorganic Organic Water
increases surface area increase wettability increase retention decrease marginal leakage and stain
2 Dentin Vol %
3
• Acid etching of enamel increases retention and adaptation of resin restorations by: • 1. increasing the surface area 2. conditioning the surface for better wetting 3. creating surface irregularities for better mechanical locking 4. producing enamel irregularities ranging from 5-30 micrometers in depth • • A. 1, 2 and 4 • B. 1 and 3 • C. 2 and 3 • D. all of the above
Resin/etched enamel interface wettability: increase contact angle: decrease critical surface tension: low surface tension; high surface energy
DENTIN MICROSTRUCTURE Quick Review
Dentin Zones ?
3 v/o
28 v/o
Dentin is a living tissue! diameter of tubules: 2.5 microns at the pulpal side, 0.5 micron i at DEJ 30,000 tubuli per square mm in the middle
4
As a function of depth or different regions within the same tooth Intertubular dentin: 96% of superficial dentin; 2% near the pulp Peritubular dentin: 3% of superficial p dentin;; Dentinal fluid: 1% of superficial 22% near the pulp
Chan
Degree of mineralization Sclerotic dentin Young dentin 1.
Occlusion of the tubules by mineral crystals 2. Contain a hypermineralized surface that resists the etching action of both self-etching primers and phosphoric acid. 3. Bacteria are often detected Resin bonding to cervical sclerotic dentin: a review. Tay, F. R. Pashley, D. H. Journal of Dentistry. 32(3):173-96, 2004 Mar.
Goals of acid etching dentin Remove the intrinsic weakness of the S.L. Demineralize the superficial dentin matrix Uncover both intertubular and peritubular dentin Acid--exposed collagen Acid
Smear layer and plugs
Vargas
Van Meerbeek
Methods to achieve dentin bonding Chelation to hydroxyapatite Bonding to collagen E Entanglement l through h h polymerization with intact collagen matrix (hybrid layer, interdiffusion zone)
Disadvantage of etching dentin Increase in dentin permeability; increased outward flow of fluid ~96% Increase in dentin wetness Increased potential for pulpal irritation Potential for denaturing of collagen Discrepancy between depth of demineralization and depth of resin penetration
5
Smear layer (S.L.) and bonding
The buffer capacity of dentin is adequate q to pprotect itself and the pulp from transient acid attack
Reduces dentin permeability Weak cohesive strength Easily removed by acids Most primers can alter the S.L. and increase the micromechanical penetration and attachment to the dentin surface
Intra- and Intertubular Permeability
Micromechanical retention by the interdiffusion of the adhesive resin system into an acidacid-exposed collagen network on the surface of the dentin ⇒ hybrid layer
Diffusion of Different Sizes Monomer
Wet & Dry Bonding
Collapsed of the fully demineralized zone (red)
Smaller molecules diffuses faster
6
Surface roughness Resin tags Hybrid layer
Total Etch Systems
Self--Etching Adh Self
E+nP E+n P+B Æ E+n E+nP PB or nEP nE P+B Æ nE nEP PB Designing Bonding Systems Self-Etching SelfPrimer
US Companies
Self-Etching SelfAdhesive
Japanese Companies hydrophobic “restorative material”
BONDING AGENT PRIMER ETCHANT ???
2=
1=
E + nP nP + B Æ E + nP nPB
Self--Etching Primer Self
B=
B=
Bis-GMA, TEGDMA BisAcetone or Alcohol
MMA, BisBis-GMA, TEGDMA, (Polymers), Acetone or Alcohol
=2
nP =
nPB =
HEMA … , HEMA, (Polymers), Alcohol, H2O, Acet
HEMA … , TEGDMA HEMA, (Polymers), Alcohol, H2O, Acet
=1
E=
E=
nEP =
nEP =
H3PO4, H2O
H3PO4, H2O
Acid Monomer, HEMA, H2O
Acid Monomer, HEMA, Polymer, (TEGDMA), H2O, Alcohol
hydrophilic tooth structure
© 2004, Bayne and Thompson, UNC School of Dentistry.
© 2004, Bayne and Thompson, UNC School of Dentistry.
Total--Etch Systems Total
E+nP E+n P+B
or nEP nEP + B Æ nE nEP PB
Self--Etch Systems Self
E+nPB E+ nPB
nEP+ nEP +B
nEPB nEP B
Self-Etching SelfPrimer
Self-Etching SelfAdhesive
A comparison of contemporary adhesives revealed that the three-step etch-and-rinse adhesives remain the 'gold standard' in terms of durability.
hydrophobic
Hybrid Layer
Hybrid Layer
Hybrid Layer
Hybrid Layer
Any kind of simplification in the clinical application procedure results in loss of bonding effectiveness. effectiveness
hydrophilic
Reliable Bonding
No Postoperative Sensitivity 1. Store in the refrigerator and use quickly. 2. Use steel or carbide burs (not diamonds) for dentin surfaces to be bonded. 3. Apply multiple layers and agitate applicator. 4. SEPs (and SEAs) should be “air dried” >10s, and “not air thinned.”
© 2004, Bayne and Thompson, UNC School of Dentistry.
3 4
5. Consider H PO etch, as well, if significant enamel involved in preparation surfaces.
Only the two-step self-etch adhesives approach the gold standard and do have some additional clinical benefits. A critical review of the durability of adhesion to tooth tissue: methods and results. De Munck, J. et al. Journal of Dental Research. 84(2):118-32, 2005 Feb.
7
Total-etch three-step – Clearfil New Bond (Kuraray) 1978* – Scotchbond Multi Multi--Purpose (3M) – Optibond (Kerr) – All All--Bond 2 (Bisco) 1
etch
2
prime
Total-etch two-step – Single Bond (3M) – Optibond Solo (Kerr) – Prime&Bond* and 2.1 and NT (Caulk)
1
2
etch
prime & bond
3
bond
Self--etch oneSelf one-step Prompt LL-Pop* (ESPE)
1 etch & prime & bond
ADHESIVE
PRIMER
8
Prime and bond NT unit dose Immediately apply generous amounts of Prime&Bond NT adhesive to thoroughly wet the tooth surfaces. These surfaces should remain wet for 20 seconds, which may necessitate applying additional adhesive.
Prime and bond NT unit dose Gently air dry for 5 seconds. Surface should have a uniform glossy l appearance Light cure Prime&Bond NT adhesive for 10 seconds.
Formation of a hard tissue barrier after pulp cappings in humans. A systematic review Olsson H. Petersson K. Rohlin M. International Endodontic Journal. 39(6):429-42, 2006 Jun. • To evaluate the evidence on the formation of a hard tissue barrier after pulp capping in humans. 171 publications; 21 studies. • The majority of studies on pulp capping using calcium hydroxide based materials reported formation of hard tissue bridging, studies on other pulp capping materials such as bonding agents presented inferior results.
The current consensus is that dentin bonding agents bond primarily _______________ to tooth structure. y A. chemically B. mechanically C. via hydrogen bonding D. by fusion
Marginal leakage, a persistent problem when bonding resin to dentin, can result in which of the following? A. sensitivity B. marginal staining C. recurrent caries D. all of the above E. none of the above
Which of the following is/are true of the etching solution? 1. Is usually 37% phosphoric acid solution or gel 2. Is allowed to over-etch the immediate vicinity of the fissure 3. Is applied liberally to the central fissure area but not allowed to contact other surfaces of the tooth 4. Is left on the tooth for 60 seconds and then rinsed away with water for 15 seconds.
9
Dental Bonding Oper 5001 Dr. Daniel C. N. Chan
Interface 1
DENTAL ADHESION
Adhesive
Steps in Forming Good Adhesion (1) Clean adherend
Adhesive System or Luting Cement
Interface 1
(2) Good wetting
Interface 2
Adherend 1
DENTAL JOINT
Adherend 2
(3) Intimate adaptation
(4) Bonding
ENAMEL, DENTIN > Liner, Base, Cement > Post and Core > Dental Amalgam > Implant >
< Composite, Amalgam < Cast Inlay, Onlay, or Crown < All-Ceramic Inlay, Onlay, or Crown < Veneers, Maryland Bridges < Orthodontic Brackets
(5) Good curing
© 2004, Bayne and Thompson, UNC School of Dentistry.
– + chemical physical mechanical bonding bonding bonding
© 2004, Bayne and Thompson, UNC School of Dentistry.
© 2004, Bayne and Thompson, UNC School of Dentistry.
BOND STRENGTH TESTING What are good bond strengths? 2
1
4 3
Macro SBS
SBS 18-35 MPa (typically ≅ 20 MPa) TBS
10-12 MPa (typically ≅ 10 MPa)
µSBS
40-80 MPa (typically ≅ 60 MPa)
3c 3b
3a 3a 3b
© 2004, Bayne and Thompson, UNC School of Dentistry.
3c
µTBS 40-80 MPa (typically ≅ 60 MPa)
µTBS
1
PERFORMANCE FACTORS 5 Categories of Factors Affecting Performance (1) OPERATOR Technical ability, Age, Eyesight, ...
(2) DESIGN SL, Bevels, Outline Form, ….
Microtensile Bond Strength Testing and Failure Analysis of Hybrid and Flowable Composites Jones, Cindy T./Chan, Daniel C. N./Pashley, David/ Fernando de Goes, Mario/Nelson, Steven K.
(3) MATERIALS Composition, Product age, T, %RH, ...
(4) INTRAORAL LOCATION Anterior-Posterior, Maxillary-Mandibular, Lingual-Facial, Premolar-Molar, Tooth Flexure, ...
(5) PATIENT F-exposure, Diet, Oral Hygiene IQ, Caries Risk, ...
J Adhes Dent 8 (2006), No 1
© 2004, Bayne and Thompson, UNC School of Dentistry.
ENAMEL MICROSTRUCTURE Quick Review DENTIN / SBMP / Z100
1. 2. 3.
Conditioning Priming Bonding
.
0
10
30
40
Shear Bond Strength (MPa + s.d.) © 2004, Bayne and Thompson, UNC School of Dentistry.
ENAMEL BONDING SYSTEMS 89v/o HA, 6% Organic, 5% Water
FROSTY APPEARANCE
Advantages of enamel etching increases surface area increase wettability increase retention decrease marginal leakage and stain
SBS = 20 MPa
2
Enamel surface morphology Featureless Types 1, 2 and 3 Cli i l Clinical significance: i ifi prismless deciduous & aprismatic cervical enamel
Ideal dentin bonding agent biocompatible bond instantly retentive to dentin bond strength > polymerization shrinkage bond strength > thermal expansion does not hydrolysis
Advantages of enamel etching
Compositon of Enamel and Dentin by Weight and Volume 100 90 80 70 60 50 40 30 20 10 0
95 86 70 50
18 12
12
Dentin Wt %
Enamel Vol %
4 1 Enamel Wt %
2525
Inorganic Organic Water
increases surface area increase wettability increase retention decrease marginal leakage and stain
2 Dentin Vol %
3
• Acid etching of enamel increases retention and adaptation of resin restorations by: • 1. increasing the surface area 2. conditioning the surface for better wetting 3. creating surface irregularities for better mechanical locking 4. producing enamel irregularities ranging from 5-30 micrometers in depth • • A. 1, 2 and 4 • B. 1 and 3 • C. 2 and 3 • D. all of the above
Resin/etched enamel interface wettability: increase contact angle: decrease critical surface tension: low surface tension; high surface energy
DENTIN MICROSTRUCTURE Quick Review
Dentin Zones ?
3 v/o
28 v/o
Dentin is a living tissue! diameter of tubules: 2.5 microns at the pulpal side, 0.5 micron i at DEJ 30,000 tubuli per square mm in the middle
4
As a function of depth or different regions within the same tooth Intertubular dentin: 96% of superficial dentin; 2% near the pulp Peritubular dentin: 3% of superficial p dentin;; Dentinal fluid: 1% of superficial 22% near the pulp
Chan
Degree of mineralization Sclerotic dentin Young dentin 1.
Occlusion of the tubules by mineral crystals 2. Contain a hypermineralized surface that resists the etching action of both self-etching primers and phosphoric acid. 3. Bacteria are often detected Resin bonding to cervical sclerotic dentin: a review. Tay, F. R. Pashley, D. H. Journal of Dentistry. 32(3):173-96, 2004 Mar.
Goals of acid etching dentin Remove the intrinsic weakness of the S.L. Demineralize the superficial dentin matrix Uncover both intertubular and peritubular dentin Acid--exposed collagen Acid
Smear layer and plugs
Vargas
Van Meerbeek
Methods to achieve dentin bonding Chelation to hydroxyapatite Bonding to collagen E Entanglement l through h h polymerization with intact collagen matrix (hybrid layer, interdiffusion zone)
Disadvantage of etching dentin Increase in dentin permeability; increased outward flow of fluid ~96% Increase in dentin wetness Increased potential for pulpal irritation Potential for denaturing of collagen Discrepancy between depth of demineralization and depth of resin penetration
5
Smear layer (S.L.) and bonding
The buffer capacity of dentin is adequate q to pprotect itself and the pulp from transient acid attack
Reduces dentin permeability Weak cohesive strength Easily removed by acids Most primers can alter the S.L. and increase the micromechanical penetration and attachment to the dentin surface
Intra- and Intertubular Permeability
Micromechanical retention by the interdiffusion of the adhesive resin system into an acidacid-exposed collagen network on the surface of the dentin ⇒ hybrid layer
Diffusion of Different Sizes Monomer
Wet & Dry Bonding
Collapsed of the fully demineralized zone (red)
Smaller molecules diffuses faster
6
Surface roughness Resin tags Hybrid layer
Total Etch Systems
Self--Etching Adh Self
E+nP E+n P+B Æ E+n E+nP PB or nEP nE P+B Æ nE nEP PB Designing Bonding Systems Self-Etching SelfPrimer
US Companies
Self-Etching SelfAdhesive
Japanese Companies hydrophobic “restorative material”
BONDING AGENT PRIMER ETCHANT ???
2=
1=
E + nP nP + B Æ E + nP nPB
Self--Etching Primer Self
B=
B=
Bis-GMA, TEGDMA BisAcetone or Alcohol
MMA, BisBis-GMA, TEGDMA, (Polymers), Acetone or Alcohol
=2
nP =
nPB =
HEMA … , HEMA, (Polymers), Alcohol, H2O, Acet
HEMA … , TEGDMA HEMA, (Polymers), Alcohol, H2O, Acet
=1
E=
E=
nEP =
nEP =
H3PO4, H2O
H3PO4, H2O
Acid Monomer, HEMA, H2O
Acid Monomer, HEMA, Polymer, (TEGDMA), H2O, Alcohol
hydrophilic tooth structure
© 2004, Bayne and Thompson, UNC School of Dentistry.
© 2004, Bayne and Thompson, UNC School of Dentistry.
Total--Etch Systems Total
E+nP E+n P+B
or nEP nEP + B Æ nE nEP PB
Self--Etch Systems Self
E+nPB E+ nPB
nEP+ nEP +B
nEPB nEP B
Self-Etching SelfPrimer
Self-Etching SelfAdhesive
A comparison of contemporary adhesives revealed that the three-step etch-and-rinse adhesives remain the 'gold standard' in terms of durability.
hydrophobic
Hybrid Layer
Hybrid Layer
Hybrid Layer
Hybrid Layer
Any kind of simplification in the clinical application procedure results in loss of bonding effectiveness. effectiveness
hydrophilic
Reliable Bonding
No Postoperative Sensitivity 1. Store in the refrigerator and use quickly. 2. Use steel or carbide burs (not diamonds) for dentin surfaces to be bonded. 3. Apply multiple layers and agitate applicator. 4. SEPs (and SEAs) should be “air dried” >10s, and “not air thinned.”
© 2004, Bayne and Thompson, UNC School of Dentistry.
3 4
5. Consider H PO etch, as well, if significant enamel involved in preparation surfaces.
Only the two-step self-etch adhesives approach the gold standard and do have some additional clinical benefits. A critical review of the durability of adhesion to tooth tissue: methods and results. De Munck, J. et al. Journal of Dental Research. 84(2):118-32, 2005 Feb.
7
Total-etch three-step – Clearfil New Bond (Kuraray) 1978* – Scotchbond Multi Multi--Purpose (3M) – Optibond (Kerr) – All All--Bond 2 (Bisco) 1
etch
2
prime
Total-etch two-step – Single Bond (3M) – Optibond Solo (Kerr) – Prime&Bond* and 2.1 and NT (Caulk)
1
2
etch
prime & bond
3
bond
Self--etch oneSelf one-step Prompt LL-Pop* (ESPE)
1 etch & prime & bond
ADHESIVE
PRIMER
8
Prime and bond NT unit dose Immediately apply generous amounts of Prime&Bond NT adhesive to thoroughly wet the tooth surfaces. These surfaces should remain wet for 20 seconds, which may necessitate applying additional adhesive.
Prime and bond NT unit dose Gently air dry for 5 seconds. Surface should have a uniform glossy l appearance Light cure Prime&Bond NT adhesive for 10 seconds.
Formation of a hard tissue barrier after pulp cappings in humans. A systematic review Olsson H. Petersson K. Rohlin M. International Endodontic Journal. 39(6):429-42, 2006 Jun. • To evaluate the evidence on the formation of a hard tissue barrier after pulp capping in humans. 171 publications; 21 studies. • The majority of studies on pulp capping using calcium hydroxide based materials reported formation of hard tissue bridging, studies on other pulp capping materials such as bonding agents presented inferior results.
The current consensus is that dentin bonding agents bond primarily _______________ to tooth structure. y A. chemically B. mechanically C. via hydrogen bonding D. by fusion
Marginal leakage, a persistent problem when bonding resin to dentin, can result in which of the following? A. sensitivity B. marginal staining C. recurrent caries D. all of the above E. none of the above
Which of the following is/are true of the etching solution? 1. Is usually 37% phosphoric acid solution or gel 2. Is allowed to over-etch the immediate vicinity of the fissure 3. Is applied liberally to the central fissure area but not allowed to contact other surfaces of the tooth 4. Is left on the tooth for 60 seconds and then rinsed away with water for 15 seconds.
9
