A biomaterial can be defined as any substance other than a drug that can be used for any period of time as part of a system that treats, augments, or replaces any tissue, organ or function of the body.
2. BIOLOGICAL REQUIREMENTS OF
DENTAL MATERIALS
A dental materials should:
1. Be nontoxic to the body.
2. Be non-irritant to the oral or other tissues.
3. Not produce allergic reactions.
4. Not be mutagenic or carcinogenic.
3. CLASSIFICATION OF MATERIALS FROM
A BIOLOGICAL PERSPECTIVE
A. Those which contact the soft tissues within the
mouth
B. Those which could affect the health of the dental
pulp
C. Those which could affect the periapical areas of
the tooth such as root-canal medicaments, filling
materials, etc.
D. Those which affect the hard tissues of the teeth
E. Those used in the dental laboratory for
fabricating dental appliances, which when
handled may be accidentally ingested or inhaled
4. EXAMPLES OF HAZARDS FROM
CHEMICALS IN DENTAL MATERIALS
• Some dental cements are acidic and may
cause pulp irritation.
• Polymer based filling materials may contain
irritating chemicals such as unreacted
monomers, which can irritate the pulp.
• Phosphoric acid is used as an etchant for
enamel.
• Mercury is used in dental amalgam, mercury
vapor is toxic.
5. • Dust from alginate impression materials may
be inhaled, some products contain lead
compounds.
• Monomer in denture base materials is a
potential irritant.
• Some people are allergic to alloys containing
nickel . Dental applications of nickel alloys
include orthodontic wires, fixed and
removable partial dentures, etc.
• Some dental porcelain powders contain
uranium.
6. • Eugenol in materials like restorations and
impressions can cause irritation and burning
in some patients.
• Laboratory materials have their hazards, such
as cyanide solution for electroplating, vapors
from low fusing metal dies, silicious particles
in investment materials, fluxes containing
fluorides asbestos, etc.
• Some periodontal dressing materials have
contained asbestos fibers.
7. • A biomaterial can be defined as any substance
other than a drug that can be used for any
period of time as part of a system that treats,
augments, or replaces any tissue, organ or
function of the body.
8. PHYSICAL FACTORS AFFECTING PULP
HEALTH
MICROLEAKAGE
• A microscopic space always exists between the
restoration and the prepared cavity.
• The use of radioisotope tracers, dyes, scanning
electron microscope and other techniques have
clearly shown that fluids, microorganisms and
oral debris can penetrate freely along the
interface between the restoration and the tooth
and progress down the walls of the cavity
preparation.
9. • Microleakage can result in:
• Secondary caries
• Stain or discoloration can also develop.
• Sensitivity
10. THERMAL CHANGE
• The temperature fluctuations can crack the
restorative materials or produce undesirable
dimensional changes in them because of
thermal expansion and contraction.
• Patients may often complain of sensitivity in a
tooth with a metallic restoration when they
are eating hot or cold foods.
• Protection from thermal changes , the dentist
must place a layer of insulating cement (called
base) under the restoration.
11. • GALVANISM
• Another cause for sensitivity is the small
currents created whenever two different
metals are present in the oral cavity .
• The presence of metallic restorations in the
mouth may cause a phenomenon called
galvanic action or galvanism. This results from
a difference in potential between dissimilar
fillings in opposing or adjacent teeth.
12. • These fillings in conjunction with saliva as
electrolyte make up an electric cell.
• When two opposing fillings contact each
other, the cell is short circuited and the
patient experiences pain.
• Stainless steel develops a higher current
density than either gold or cobalt chromium
alloys when in contact with an amalgam
restoration
13. CLASSIFICATION OF ADVERSE
REACTIONS FROM DENTAL MATERIALS
• 1. Toxic
• 2. Inflammatory
• 3. Allergic
• 4. Mutagenic
Adverse effects may also be classified as:
• 1. Local- A local effect is a result of the direct contact of the material to
the regions immediately adjacent to the material. Example of a local
reaction is the allergic response of the oral mucosa to the denture seen in
some individuals.
• 2. Systemic- A systemic reaction is caused by the absorption of the
material into the body through local absorption, ingestion or inhalation.
14. TOXICITY EVALUATION
Toxicity test are classified as:
Level I Tests (Screening Tests)
• The material is first checked for acute systemic
toxicity and for its cytotoxic, irritational, allergic
and carcinogenic potentials.
Level II (Usage Tests)
• The material is tested in experimental animals
similar to how it is used in humans.
15. Level III (Human Trials)
• Once the material has passed screening and
usage tests in animals, it is ready for trials in
humans. The reactions and performance
under clinical conditions are studied.
16. THERAPEUTIC EFFECTS OF DENTAL
MATERIALS
• Zinc oxide Eugenol cement has a pain relieving
effect on irritated pulp.
• Calcium hydroxide pulp capping agent
promotes the formation of secondary dentin
and helps repair dentinal tissue.
17. INFECTION CONTROL
• There are many ways by which
microorganisms can spread:
1. Contaminated instruments and needles.
2. Direct splashing of saliva and blood into the
mouth or on to wounds.
3. Breathing of contaminated aerosol from the
air-rotor handpiece.
4. Through contaminated dental materials.
18. DISINFECTION OF DENTAL MATERIALS
Impressions
• Impressions are the main source of spread of infection
among the dental materials.
• The disinfectant must not affect its properties and accuracy.
• Materials may be disinfected by:
1. Immersion in a disinfectant
2. Spraying with a disinfectant
3. Incorporating the disinfectant into the material as part of its
composition.
