Pediatric Dentistry I Forth Year

1. • No truly adhesive dental material. No restorative
dental material exactly duplicates the physical
properties of tooth structure.
• Gap between the walls of the prepared cavity
and the restoration interrupt acid, food debris,
and microorganisms.
• Microleakage may be the precursor of
secondary caries, marginal deterioration,
postoperative sensitivity, and pulp pathology.
Dental materials

2. • Microleakage is problem in the pediatric
patient because the floor of the cavity
preparation may be close to the pulp
• Insult to the pulp caused by the seepage
of irritants that penetrate around the
restoration and through the thin layer of
dentin, or a microscopic pulpal exposure,
may produce irreversible pulp damage.
Dental materials

3. • For true adhesion
• Bonding chemical adhesion
• Materials are the polycarboxylate and glass
ionomer cements.
• No need for the typical cavity preparation
because adhesion eliminate the need for
mechanical retention by the cavity preparation.
No need for auxiliary aids, as cavity varnishes
and etching techniques, to minimize the
microleakage around direct filling restorations.
Dental materials

4. • the surface energy of most restorative
materials, metallic ones, is higher than of
normal intact tooth structure. Therefore,
debris accumulates on the surface of
restorations more than on the adjoining
enamel high incidence of
secondary caries associated with most
restorative materials, except for those that
release fluoride ion.
Dental materials

5. Dental materials
• For disinfection procedures. Most materials are
now packaged for unit-dose delivery at chair
side, which makes infection control much easier.
• Safety handling any hazardous materials
• Environmental safety for all waste discharged
from the dental office. Disposal of hazardous
materials.

6. Dental Material Properties
WettabilitySolubilityGalvanismCorrosion
ViscosityRetentionFlow
Biting
forces
Thermal
expansionMicroleakageElasticityAdhesion
ThermalHardness
Dimensional
changeAcidity

7. Biting Forces

8. Materials Preparing for Restoration
Liner
BasesVarnish
Cements
Bonding
agents

9. Dental Cements
Varnish
Sedative Base
Liner
Luting
Cements

11. Cavity varnish
• When varnish is painted onto the cavity
preparation, the solvent evaporates and
leaves a thin resin film.
• The varnish reduce microleakage

12. Copalite Varnish

13. • CEMENTS BASE
• LUTING CEMENTS
– ZINC PHOSPHATE CEMENT setting time, fluidity,
moderate degree of intraoral solubility and film thickness.
– It does not have an anticariogenic effect, does not adhere
to tooth structure & irritant to the pulp.
• POLYCARBOXYLATE CEMENT
– a chemical bond is formed between the cement liquid and
the calcium in the hydroxyapatite in enamel and dentin.
– To remove smear layer cleaning the surface is a 10- to
15-second swabbing with 10% polyacrylic acid.
– the mix should be completed within 30 seconds.
– If the mix is too thick, insufficient acid is present to
produce bonding to the tooth.
– If excess liquid is used, the intraoral solubility increases
significantly.
CEMENTS

14. CEMENTS
• GLASS IONOMER CEMENT
• restorative material (type II) , as a luting agent (type I), and
as a base and liner material (type III).
• The powder is a fluoro-aluminosilicate glass with maleic acid,
• luting agent for cast restorations, GIC has been employed for
bonding orthodontic brackets to acid-etched enamel
• RESIN-MODIFIED GLASS IONOMER
CEMENTS
• a comonomer of acrylic acid and a methacrylate such as
hydroxyethyl methacrylate in the same manner as light-
activated restorative resin composites.

15. CEMENT BASES
• Zinc phosphate, hard-setting calcium
hydroxide, zinc oxide—eugenol, and glass
ionomer cements have sufficient strength
to serve effectively

16. CEMENT BASES
• The function of the cement base is to
promote recovery of the injured pulp and
to protect it against further insult.
• The base serves as a thermal insulator an
replaces missing dentin when it is used
under the metallic restoration.
• A base must be able to support the
condensation of the restorative material
placed over it.

17. Cement base
• A minimum thickness of cement to
promote recovery of the injured pulp and
to protect it against further insult
approximately 0.5 mm
• able to support the condensation of the
restorative material placed over it.

19. Luting Cements
• Permanent
• Temporary
• Intermediate
Compomer
Resin
Glass
Ionomer
Polycarboxylate
Zinc Oxide
Eugenol
Zinc
Phosphate
Luting

20. Temporary & Permanent
Restorations
• Biologic characteristics, have minimal
solubility, and be rigid, strong, and
resistant to abrasion.
– zinc oxide-eugenol cement mixture with
polymers
– Type II glass ionomer cements or the newer
resinmodified GICs

21. Resin based composites (RBC)
• Resin matrix (Bis-GMA) with inorganic
filler particles.
1. Filler content-
• Filled vs Unfilled
• Flowable vs packable
• Anterior vs posterior composite
2. Particle size
macro, microfilled and hybrids

22. Restorative Resins
•CONVENTIONAL COMPOSITES
matrix is bisphenol A-glycidyldimethacrylate (bis- GMA) or
urethane dimethacrylate resin. Triethylene glycol
dimethacrylate, a lower-viscosity resin 70-80% macro fillers
are ground particles of fused silica, crystalline quartz, and soft
glasses such as barium, strontium, and zirconium silicate
glass (reduces the coefficient of thermal expansion &
polymerization shrinkage and increases the hardness).
•MICROFILLED COMPOSITES
–small silica filler particle, 0.02 to 0.04 μm, microfine,
microfilled, or polishable resins
•SMALL-PARTICLE AND HYBRID COMPOSITES
–radiopaque glass particles with an average size of 0.6 to
1.0 pm in addition to 10%-20% colloidal silica. The total
filler level, 70% to 80%,

23. • LIGHT-CURED COMPOSITES
• POSTERIOR COMPOSITE RESTORATION
• The improved strength, hardness, and modulus of elasticity of
some of the newer composite resins, with their low thermal
conductivity and superior esthetics, indicate that they may
serve as alternatives for amalgam in the restoration of occlusal
and proximal surfaces in posterior teeth clinical wear of less
than 20 μm per year over a 5-year period.
Restorative Resins

24. Resin Restorations
Steps:
Etch, wash, dry or dessicate?
Enamel and Dentin adhesives
Composite selection and placement
Curing tools and techniques
Disadvantages:
1. Polymerization shrinkage
2. Technique sensitive
3. Performance of posterior composites in large, stress
bearing preparations is questionable

25. Dentin/Enamel adhesives in
Pediatric Dentistry
Dentin bonding agents or Primers:
Smear layer
Etch
Hydrophillic and hydrophobic component (HEMA)
Enamel adhesives or bonding agents:
Hydrophobic resin such as Bis-GMA
Hybrid layer copolymerized
Layer of primer, bonding resin and collagen
1. 3-step total etch
2. Total etch using prime and bond
3. Self etch primers with bonding agent
4. All-in-one adhesives e.g.- prompt Lpops

26. Acid-Etching Technique
• The enamel is etched with a solution of
phosphoric acid (35%) for 15 to 20 seconds
or gel.
• Rinse to remove the debris produced during
etching. A minimum wash time of 30
seconds
• The etched surface must then be dried for at
least 15 seconds.
• If the surface is accidentally contaminated
by saliva. Rather, the surface should be re-
etched for 10 seconds, washed, and dried.
• Resin bond strengths to etched enamel
range from 16 to 22 MPa.

27. Bonding Agents
•bis-GMA resin matrix material diluted with
a low-viscosity methacrylate monomer.

28. Amalgam
No polymerization shrinkage
Moisture forgiving
Excellent mechanical properties
Mercury toxicity
Esthetics

29. Amalgam
• SELECTION OF THE ALLOY
– Lathe-cut alloys
– Spherical alloys. amalgamate very readily with smaller
amounts of mercury & gains strength more rapidly
• HIGH-COPPER ALLOYS
– The original dental amalgam alloys were alloys of silver
and tin with a maximum of 6% copper.
– High-copper amalgam alloys have (11% to 30%) copper
have low creep.
– Creep is the tendency of a material to deform
continuously under a constant applied stress. This
associated with the marginal breakdown (ditching).
– Dental amalgam permits a maxi-mum of 3% creep, a
modern high-copper amalgam alloy should not exceed
1% creep.

30. • MERCURY/ALLOY RATIO
– Pre-filled, disposable mixing capsules containing the proper
amounts of alloy and mercury.
• The alloy/mercury ratio is accurately preproportioned.
• The need for disinfection procedures is minimized (capsule is
discarded after use).
• Exposure of dental personnel and environmental contamination by
mercury vapor is minimized.
• TRITURATION
– Depend on the composition of the alloy, the mercury/alloy ratio,
the size of mix,
– Undertriturated mix appears dry and sandy and does not
cohere into a single mass.
• Set too rapidly,
• Results in a high residual mercury content, reduced strength, and
• The increased of fracture or marginal breakdown.
Amalgam manipulation to control of
mercury

31. Amalgam
• MECHANICAL AMALGAMATORS
• Trituration speed, time, significantly influences the
rate at which some amalgams
• CONDENSATION
• to adapt the amalgam to the walls of the cavity
preparation,
• to minimize the formation of internal voids, &
• to express excess mercury from the amalgam.
• MOISTURE
– If zinc is present in the alloy, react with water,
and hydrogen gas will be formed lead to
delayed expansion
– zinc-free, high-copper alloy should be used
where moisture control is difficult.
• MARGINAL BREAKDOWN AND BULK
FRACTURE

32. Amalgam
• BONDED AMALGAM RESTORATIONS
• MERCURY TOXICITY
• Dental personnel potentially are exposed daily to mercury
through skin or by ingestion, the primary risk is from
inhalation
• The maximum level considered safe for occupational
exposure is 50 p.g of mercury per cubic meter of air
averaged over a standard 8-hour workday.
• The dental operatory should be well ventilated.
• All mercury waste and amalgam scrap removed during
placement or removal of amalgam restorations should be
collected and stored in well-sealed containers.
• When amalgam is cut, water spray and high-speed
evacuation should be used.

33. Preventive Materials
1. Fluoride gels, foam and varnish:
Used for remineralization of decalcified
enamel and incipient caries.
2. Sealants:
Indicated for preventing and arresting
incipient lesions.
Available as clear or white, filled or unfilled,
containing Fluoride or not.

34. SSC- Primary and Permanent
• Full coverage, metallic, definative
restorations
• Available as:
pretrimmed (Unitek ), precontoured and
festooned (Ni- ChroION crowns)
• Durable and costeffective

35. Summery
• Primary teeth are a temporary dentition
with known life expectancies of each tooth.
By matching the ‘right’ restoration with the
expected lifespan of the tooth, we can
succeed in providing a ‘permanent’
restoration that will never have to be
replaced.”