3. INTRODUCTION
Dental bonding is a dental procedure in which a
dentist applies a tooth-colored resin material (a
durable plastic material) and cures it with visible,
blue light.
• Tooth bonding techniques have
various clinical applications
including operative dentistry and
preventive dentistry as well
as cosmetic and pediatric
dentistry, prosthodontics,
and orthodontics
4. DEFINITION
• Bonding agents can be defined as material
of low viscosity, when applied on the tooth
surface forms thin film after setting.
• This thin film strongly
bonded to tooth surface,
on which the viscous
composite restorative
resin is applied. This
sets forming an
integrated resin
restoration.
5. COMPONENTS:
ETCHING: dissolution of substrate, removed by rinsing to
enhance intimate contact of adhesive.
PRIMING: cleaning, structural
alteration and increasing
adhesiveness of the substrate.
ADHESIVES: monomer (or
related) that penetrates and
establishes intimate contact with
conditioned tissue substrate,
polymerizes, and forms a strong
bond between a such substrate
and restorative material.
Etching
Priming
Adhesi
ve
6. 1. The procedure must be safe and biologically acceptable.
2. The level of bond strength must be clinically significant to avoid
discoloration at the margins and secondary caries.
3. The bond strength must be routinely achieved so that
predictable results are obtained.
4. The bond must be established
quickly in order to permit
immediate finishing.
5. The bond must be stable in
vivo for a clinically significant
period of time.
7. 1. The material should be retentive to dentin at a clinically
acceptable level, and it should be able to withstand intraoral
forces of occlusion and mastication.
2. The bond should be instantaneous once the material has set.
3. The material and technique must be biocompatible.
4. The material should resist the forces of
polymerization shrinkage of composite resins
and the coefficient of thermal expansion and
contraction to eliminate microleakage.
5. The material should create a long-lasting
bond to dentin
8. Dentin bonding is highly
sensitive technique because:
of fluid flow in the dentinal
tubules
deep dentin has more tubules
(more fluid, hence lower Bond
Strengths)
varies from tooth to tooth in
the same mouth (anterior
teeth Shear Bond Strengths >
molars)
9. Challenges of Bonding to
Dentin
Dentin is 17 percent collagen by volume. This collagen is
inaccessible due to surrounding hydroxyl apatite crystals.
Micromechanical retention with dentin depends only on
dentinal tubules. These tubules contain fluid which would be
an impediment to bonding.
The number of tubules available for bond also varies
depending on location, with deep dentin having more tubules
than superficial dentin.
Dentin bonding also varies with physiologic or pathologic
changes in dentin, direction of tubules and the type of dentin
available for bonding
12. primer and bonding resin applied to
etched enamel and dentin by total
etching the preparation with 40%
phosphoric acid.
They penetrate the intertubuler dentin
for a depth of 2-4 micrometers forming
a resin dentine interdiffusion zone or
hybridization zone.
13.
14. hybridization is defined as “the phenomena of
replacement of the hydroxyapatite and water of the
dentin surface by resin, this resin in combination with
collagen fiber , forms a hybrid layer (zone).”
15. They have the ability to bonds as strongly to dentine as to
enamel (total etch) .
Ability to bond to moist dentin.
Multiple bottles system.
3 step application etching + primer +bonding
Bonds strength 17 to 25 Mpa (high bond strength).
Multiple substrate bonding to, porcelain and indirect
composite.
Ex: All-bond 2, Optibond FL and Scotch Bond multipurpose.
17. These are essentially distinguished by being
“two-step” system.
Primer and bonding agent are available in
single bottle.
Easy to use and predictable.
Reduced postoperative sensitivity .
19. It was introduced in late 1990 and early 2005:
Self-etching primers simultaneously condition (etch)
and prime the dentin (and enamel).
Two primary types of self-etching primers
exist:
1. Two-step, self-etch adhesives, where
an acidic self-etch primer is used
instead of phosphoric acid to etch the
enamel and dentin, followed by the
application of the adhesive.
2. One-step "all-in-one" adhesives where
etching, priming and bonding occur
simultaneously through application of the
self-etch primer.
20. • Simple to use.
• Eliminates variables associated
with “wet bonding”.
• Depth of etch is self-limiting.
• Sensitivity is reduced, even with incomplete
coverage (smear plugs still intact in areas not
covered).
21. • Bond strengths to enamel are typically lower than
for total-etch adhesives.
• Some materials do not adequately etch uncut
enamel.
• Bond strengths to auto-curing composites are poor.
• Clinical performance not yet time proven; bond
durability questionable, especially for all-in-one types
(hydrolysis).
The bond strength to dentin and enamel is lower
than the fourth and fifth generation system.
22. There are still concerns about the quality of bonding of SE
adhesives to enamel. If enamel is left unprepared, it is
resistant to etching and adhesion with most SE adhesives.
For preparations that include both dentin and enamel,
it is recommended that the enamel should be prepared
with a diamond bur to optimize the bond to the enamel.
Currently, the use of an SE is
contraindicated adhesive for
- restoring Class IV incisal edge fractures.
- esthetic facial veneering.
- diastema closures with direct composite
resin and bonding porcelain veneers.
23. Literature is abundant comparing bond strengths of the
total etch and self etch adhesives on enamel and dentin
of human permanent teeth but there is a relatively
paucity of data regarding dental adhesion to primary
dentin.
Higher bond strength values were
obtained for permanent dentin
compared to primary dentin.
Similar results have been obtained in studies which
had reported that:
This lower bond strength values in primary teeth
were related with the physical, micro morphological
and chemical differences between primary and
permanent teeth.
Comparing the Bond strength between
the primary and permanent dentin
24. • Gel etchants need to be washed
longer > liquid.
• Common wash times 5 - 15 sec
• Patient’s breath can reduce
bond strength.
• All-purpose bonding agents
contain large amounts of
solvent (must be evaporated).
25. • Bond Strengths of all systems are lower for dentin
than for enamel.
• Layering of bonding/ flowable agents to thicken
surface layer greatly reduces microleakage.
• Filled resins increase toughness of adhesive (not
strength).
• For wet/moist bonding: best with use of cotton pellet.
• Refrigeration extends shelf life of all Dentin Bonding
Agents.
27. The choice may be Confusing.
It is easy for the clinician to believe
that a new system is better over the
old ones but this may not always be
true.
SO:
Chemistry is more important than the
company.
Technique is more important than the
material.
What we have to
choose:
