Bonding Mechanism

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CONSERVATIVE OPERATIVE DENTISTRYPage 1
Lecture: Bonding Systems (Enamel, Dentin, Compomer, Amalgam, Resin Cement) OVERVIEW OF BONDING SYSTEMS:
A. Goals of Bonding (and Adhesion):
1.Sealing
2.Retention
B. Definitions and Terminology for Adhesion:

1.Terminology for adhesion:
a. Adhesive- material forming the layer
b. Adherend- substrate being bonded
c.System (EBS, DBS) and
agents (EBA, DBA, ABA)
2.Adhesive systems:
a. Adhesive layer
(Adherend/ Adhesive)
b. Adhesive joint
(Adherend-1/ Adhesive/ Adherend-2)

Bonding system applications:Adherend-1:
SealantEnamel
Surface SealersComposite
Enamel bonding systemEnamel
Dentin bonding systemDentin
Amalgam bonding systemEnamel/Dentin
Composite cementEnamel/Dentin
Crown and Bridge CementEnamel/Dentin
Orthodontic bonding systemEnamel
Maryland bridge cementEnamel
Porcelain veneersEnamel
PFM repairsMetal/Porcelain

AdherendAdhesiveDENTAL
ADHESION

DENTAL
AdherendAdherendADHESIVE
JOINT

Interface #1Interface #2

Adhesive:Adherend-2:
Sealant
Sealer
EBAComposite
Primer-DBAComposite
ABAAmalgam
BA/Comp/BA Inlays
BA/Comp/BA Metal/Ceramic
CompositeBracket
CompositeMetal Alloy
CompositePorcelain
Composite

C. Steps in Formation of Good Adhesion (for Retention):

(1) Clean adherend

(2) Good wetting

(3) Intimate adaptation

(4) Bonding

(5) Good curing

-
+
physical chemical
bondingbonding mechanical bonding

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Dental Materials"Enamel-Dentin-Amalgam Bonding and Composite Cements"Page 2 D. Bond Strengths (Measure of Destruction of Adhesion): (1 MPa = 145 psi)
1A. Shear Bond Strength (SBS):
> SBS = (1.5-2) x TBS;
> SBS = (1/3-1/4) x TBS
> Enamel bonding = 18-22 MPa
> Dentin bonding = 10-35 MPa
> Amalgam bonding = 3-22 MPa
> SBS for dentin = 165 MPa

2A. Tensile Bond Strength (TBS):

E. Factors determining performance:

1B. Micro-Shear Bond Strength (SBS)

2B. Micro-Tensile Bond Strength (TBS)

1.Operator factors (etching, washing, drying, and bonding techniques)
2.Design (preparation) and Substrate factors (smear layer, moisture content, ...)
3.Materials factors (product, modulus, thickness, ...)

4.Tooth location factors (lesion size and shape, local morphology, flexure, arch)
5.Patient factors (F exposure, diet, age, occlusal stress, ...)
F. Design (functions) of bonding systems (3,2,1-components):
1.Conditioning (clean and/or...
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