biocompatibility of dental material and the test related to biocompatabilty

1. BIOCOMPATIBILITYOF DENTALMATERIALS
Presented By :-
Mayank Aggarwal
PG 1st Year

2. Contents
• Introduction
• Definition
• Requirement of dental materials
• Tests for evaluation of biocompatibility
• Allergic responses to dental materials
• Standards that regulate the measurement of biocompatibility
• Biocompatibility of dental materials
• Reaction of other oral soft tissues to restorative materials
• Reaction of bone & soft tissues to implant materials
• References
• Conclusion

3. INTRODUCTION
3
• Biocompatibility refers to the study of interaction of various
materials with human tissues.
• Materials used in dentistry come into direct contact with the hard tissues
of teeth, the oral mucosa, the pulp & the periapical tissues.
• Due to this intimate, long term contact, the materials
Should exhibit a high degreeof biocompatibility.
• For the biocompatibility of a biomaterial , it is not only important that
minimal diffusible substances are released when it isin body contact, but the
material must also solve the purposeforwhich it has been designed.

4. Biocompatibility is formally defined as the ability of a material to elicit an
appropriatebiological response in a given application in the body. (CRAIG)
4
COMPATIBILITY: (To compath-to sympathize with) :A state in which two things are
able to exist or occur together without problems or conflict.
BIOMATERIAL:A synthetic material used to replace part of a living system or to
function in living tissue.
General definition: The ability of a biomaterial to perform its desired function with
respect to a medical (or dental) therapy, without eliciting any undesirable local or
systemic effects in the recipient or beneficiary of that therapy, but generating the
most appropriate beneficial cellular or tissue response in that specific situation,
and optimizing the clinically relevant performance
of that therapy (Williams, 2008)

5. • They should not sensitize and produce allergic
reactions.
• They should not undergo biodegradations.
• They should not be carcinogenic.
• They should not contain any toxic diffusible substances
which get released and enter into the circulatory system.
• They should not be harmful to soft & hard tissues of the
oral cavity in particular and the whole body in general.
BIOCOMPATIBILITY REQUIREMENTS
5

6. WHYIS BIOCOMPATIBILITY RELEVANT TO THE
DENTIST ?
5
BIOCOMPATIBILIY
Safety of
the patient
Safety of the
dental staff
Regulatory
compliance
issue
Legal
liability

7. BIOLOGICAL INTERFACE
6
• PLACEMENT OF A MATERIAL IN THE BODY CREATES AN INTERFACE
THAT ISNORMALLY NOT PRESENT.
• THIS INTERFACE IS NOT STATIC, RATHER IT IS THE SITE OF MANY DYNAMIC
INTERACTIONS BETWEEN THE MATERIAL & THE BODY THROUGH WHICH THE
BODY MAY ALTER THE MATERIALOR THE MATERIAL MAY ALTER THE BODY.
.
The activity of this interface depends on
1. The location in the body.
2. Its duration in the body.
3. The properties of the material.
4. Health of the host.
4 types of interaction can take place:
1. Between the material and oral cavity.
2.Between the material and the pulp (Via the dentinal
tubules).
3. Between the material and periodontium.
4. Between the material and the periapical bone.

8. ADVERSEFFECTSOFDENTAL MATERIALS
8

9. TOXICITY
• Toxicity of a material describes the ability to damage a
biological systembychemical means.
• Placement of a foreign material in the body carries the
possibility of toxicity
• Dental materials may release certain substances
which can cause toxicity.
9

10. IMMUNOTOXICITY
• Substances leached from materials can alter immune system
cells, resulting in enormous biological consequences because
ofthe amplifying natureofimmune cells.
• This may lead to:
• 1. IMPAIRED HOST DEFENCE.
• 2. TISSUE DAMAGE.
• Glutathione content of human monocytes which helps in
maintaining oxidative stressin cells: mercuryions areknown to
increase whereaspalladium ions decreasethe cells’ glutathione
content.
9

11. SYSTEMIC TOXICITY
10
SYSTEMIC TOXICITY
Here site of application & site of adverse
reactions are different.
Almost all dental materials release substances
into the oral cavity, from where they may enter
the systemic circulation via different routes.
According to the time frame:
 1. Acute (up to an exposure period of 24 h)
2. Subacute (up to 3 months)
3. Chronic toxicity are differentiated

12. LOCAL TOXICITY
11
Inflammation of the gingiva in
contact with a porcelain-
fused-to-metal crown
Pulp necrosis after
application of resin fillings
•Substances released from dental
materials may generate a reaction
(e.g., inflammation or necrosis) in
adjacent tissues such as oral
mucosa/ gingiva, pulp or alveolar
bone.
• There may be other factors
like:
1. Bacterial accumulation on the
surface, at the margin, or under
a material.
2. Mechanical/physical
irritation, such as pressure
caused by dentures.

13. INFLAMMATION
12
inflammatory responseis complex
but involves the Activation of
host’s immune
Systemto ward offsome threat
Histologically,the inflammatory response
is characterized by
Edemaofthe tissue.
Inflammatory cells infiltration such as
neutrophils (in the short term) or
monocytes.

14. ALLERGY
• An allergic reaction to a substance can be triggered if the organism
waspreviously sensitizedto thiscompound.
• Dental materials may cause allergies of type I (immediate reaction)
and typeiv (delayed reaction).
13
IgE, IgG
-Monocytes & Tcells

15. CONCURRENT- ALLERGY
• If an individual is allergic to a
particular element, then it may
be assumed that he will also
allergic to chemically similar
elements. For e.g.–Nickel and
palladium.
CROSS-ALLERGY
• It is generated by 2 allergen that
are frequently present at same
time within a material oral
environment. e.g.–Ethylene glycol
dimethacrylate (EGDMA)
Hydroxyethyl Methacrylate
(HEMA)
ALLERGY

16. 14
Contact urticaria : A local immediate
erythemal or pruritic reaction at the site
of epidermal or mucosal contact
following occupational exposure to latex
proteins in disposable gloves
Delayed reaction : Specific sensitized T
lymphocytes, which react with the allergen and
release lymphokines, eliciting an inflammatory
reaction.
e.g. Pronounced gingivitis of an orthodontic patient
(nickel- containing device) who revealed positive
reaction in a
patch test. The most important differential diagnosis
would be
“plaque-associated” inflammation

17. OTHER REACTIONS
15
Genotoxicity
Refers to the ability of
substance released from
materials to cause alterations of
the genome
Mutagenicity
It is the ability of a substance
to pass genetic damage on the
next generation.
e.g. – Ni, Cu and Be are known
mutagens.
Carcinogenicity:
It is the ability of a material or
substance released from it to
induce malignant tumours
.
Teratogenicity:
It is the ability of certain
substance to cause
malformation during embryonic
development
.

18. LEVELS OF BIOCOMPATIBILITY
• GENERAL BIOCOMPATIBILITY :
Determines the toxicity of the material at a cellular level.
• IMMUNOLOGICALBIOCOMPATIBILITY :
Determines of how an individual reacts to the material.
• Tests performed to determine the body’s immunological response are:
1. Clifford Materials Reactivity Test
2. Kinesiologic testing
When evaluating a Clifford test, a material that tests NS (not suitable) should
not be used. On the other hand, materials that test S(suitable) should, ideally,
be further tested.

19. BIO-ENERGETIC BIOCOMPATIBILITY:
• Using Electro dermal Screening (EDS) and Applied Kinesiology (AK or
Muscle Testing),interaction between body & material is determined
on an energetic level.
• If energetically incompatible materials are used, interferences are
created on the meridians associated with the teeth being restored.

20. MEASURING THE BIOCOMPATIBILITY:
Biocompatibility of a material cannot be evaluated by using a single
test rather than a group of various techniques.
The material needs to be evaluated by conducting a series of structured in vivo
and in vitro test
Autian (1970) was the first to propose a structured approach in biocompatibility testing:
1. Non specific toxicity (Cell culture or small laboratory animals): These tests are
carried out on models which do not simulate clinical situation.
2. Specific toxicity (Usage tests e.g. in sub human primates):Theses Tests are
conducted on models which simulate the clinical situation.
3. Clinical testing in humans.

21. • In 1984, it was Lange land who proposed a sequence which was later
adopted as the ISO technical report 7405.
Initial Test
Secondary Test
Usage
Test
(Cytotoxcity ,
Mutagenicity)
(Sensitization,
Implantation test ,
Mucosal Irritation)

22. • According to Phillips there are three basic types of tests used to measure
biocompatibility of dental materials
In-vitro Test Animal Test Usage Test

23. IN VITRO TEST
18
• Done outside a living organism
• Placement of a material or its component in contact
with a cell system, enzyme or other biological
system
• Test tube, cell culture dish, flask , or other
container
CLASSIFICATION OF IN VITRO TESTS
DIRECT TEST
INDIRECT
TEST
MATERIAL CONTACT EXTRACT CONTACT

24. 1. TESTS FOR CYTOTOXICITY
• CELL DEATH – measure CELL NUMBER OR GROWTH before and after
exposure to that material.
• DIRECT CONTACT TEST cells are placed in a well of a cell-culture dish,
where they attach. The material is then placed in the testsystem.
• If the material is not cytotoxic, cells will remain attached to the well and will
proliferate over time.
• If the material is cytotoxic, cells may stop growing or exhibitcytopathic
changes or detach from the well
The morphology of the fibroblasts
indicates that they are alive and are not
suffering from a toxic response
The fibroblasts are rounded19
and detached indicating that
they are either dead or dying.

25. MEMBRANE PERMEABILITY
20
Measures cytotoxicity by the ease with which a dye can pass
through a cell membrane, because membrane permeability is
equivalent to or very nearly equivalent to cell death
Dyes are of two types:
1. Vital dyes: They are actively transported into viable cells, where they are
retained unless Cytotoxic effects increase the permeability of the membrane.
Ex: Neutral red
2. Non vital dyes: These are not actively transported and are taken up if
membrane permeability has been compromised by cytotoxicity.Ex:Trypanblue

26. TESTS THAT USEBARRIERS(INDIRECTTESTS)
1. Agar overlay method,
• A monolayer cell culture is used.
• The cell stained with neutral red vital stain dye.
• Then agar layer is placed over the cells on which the
test material is incubated for 24 hrs.
• Agar forms a barrier between the cells and the
material.
• If the test material is cytotoxic, it will lead to loss of
dye within cells as lysis occurs.
24

27. Millipore filter assay,
• A cellulose acetate filter having 0.45µm filter is
used
• Cells are grown on one side of the filter and the
test material placed on the opposite side of filter.
• Any leachable substance from the test material
must diffuse through the pores to exert a
cytotoxic effect on the cells.
27

28. DENTIN DISC BARRIER TEST
• A DENTIN DISK FORMS A BARRIER BETWEEN THE TEST
MATERIALAND THE TARGETCELLS
25
• The material is placed on one side
(A)of the dentin disk (B) in the
device used to hold the dentin
disk.
• Collection fluid (cell culture
medium or saline) is on the other
side of the disk (C).
• Components of the material may
diffuse through the dentin and
reach the culture.

29. MUTAGENESISASSAYS
1. AMESTEST:
• It uses mutant stocks of salmonella
typhimurium that require exogenous
histidine.
• Native stocks of bacteria do not
require exogenous histidine.
• If the mutant stocks bacteria are
treated with a mutagen there will
be a mutation back to the normal
state and growth in histidine free
medium will occur. 26
2. STYLES CELL TRANSFORMATION TEST :
done in mammalian cell.
Assess the effect of a biomaterial
on a cell’s genetic material

30. 21
TESTS FOR CELL METABOLISM OR CELL
FUNCTION:
NBT(nitro blue tetrazolium)
WST(water soluble tetrazolium)
• Use biosynthetic or enzymatic activity of cells to assess Cytotoxic
response
• Usually assess DNA synthesis or Protein synthesis
Types:
• MTT(dimethyl- thiazole -diphenyl - tetrazolium bromide)
• XTT(methoxy -nitro –sulphophenyl- tetrazolium –carboxanilide salt
ASSAYS

31. IN VITRO TEST
27
ADVANTAGES
•Quick to perform
•Least expensive
•Can be standardized
•Large scale screening
•Good experimental control
DISADVANTAGES
•Questionable relevance to the
final in vivo use of the material
•Lack of inflammatory or other
tissue protective mechanisms in
the in vitro environment

32. ANIMAL TEST
• USUALLY INVOLVING MAMMALS SUCH AS MICE, RATS,
HAMSTERS, ORGUINEA PIGS, AND ARE DISTINCT FROM
USAGE TESTS IN THAT THE MATERIAL IS NOT PLACED IN THE
ANIMAL WITH REGARDTO ITS FINAL USE
32

33. 1.MUCOUS MEMBRANE IRRITATION TEST
• Determines whether the material causes inflammation to mucous membrane or
abraded skin
• Placing the test materials and positive and negative controls into contactwith
rabbit oral tissue.
• The animals are then sacrificed and biopsy specimens are prepared for
histological evaluation of inflammatory changes.
33

34. 2.SKIN- SENSITIZATION TEST
• The materials are injected
INTRADERMALLY to test for
development of skin hypersensitivity
reactions.
• The injection is followed by adhesive
patches containing the test substance.
• If hypersensitivity developed from
initial injection, the patch will elicit an
inflammatory response. 30

35. 3. IMPLANTATION TESTS
• For implantation tests, materials are implanted
subcutaneously, intramuscularly, or in the
bone of an experimental animal .
• After different periods of implantation of the
material in the tissues (between 1 week and
several months), the adjacent tissue is
investigated macroscopically and
microscopically.
• After a short implantation time (1–2 weeks),
degrees of inflammation surrounding the
implant will primarily be assessed.
31
Formation of an abscess at the
interface between material and
connective tissue

36. ANIMAL TEST
32
ADVANTAGES
interactions
•Response more
comprehensive than in
vitro test
•More relevant than in
vitro test
DISADVANTAGES
•Allows complex systemic •Questionable relevance to the final
in vivo use of the material
•Expensive
•Time consuming
•Legal/ethical concerns
•Difficult to control
•Difficult to interpret and quantify

37. IN USAGE TEST
33
LARGER ANIMALS or IN HUMAN VOLUNTEERS
Requires that material be placed in a situation identical to
its intended clinical use
GOLD STANDARD
• DENTAL PULP IRRITATIONTEST
• MUCOSAAND GINGIVAL USAGETEST
• INTRAOSSEOUS IMPLANT TEST

38. 1. DENTAL PULPIRRITATION TEST
34
TEST MATERIAL PLACED IN CLASS V CAVITY
PREPAREDIN INTACT, NON CARIOUS TEETH
TEETH REMOVED, SECTIONED FOR MICROSCOPIC
EXAMINATION
TISSUE NECROSIS AND INFLAMMATION GRADED
ACCORDING TO INTENSITY
RECENT APPROACH IS TO USE TEETH WITH
INDUCED PULPITIS WHICH ALLOW
EVALUATION OF THE TYPE AND AMOUNT OF
REPARATIVE DENTIN FORMED AS AN
INFLAMMED PULP REACTS DIFFERENTLY TO
RESTORATIVE MATERIALS

39. 2. INTRAOSSEOUS IMPLANT TEST
• MATERIALS USED FOR DENTAL
IMPLANTS ARE INSERTED INTO THE
JAW.
• Criteria for implant success
• Early implant success 1-3 years
• Intermediate implant success 3-7 years
• Long term implant success >7 years
• Tests used
 Passage of periodontal probe along side of the
implant
 Mobility of the implant
 Radiographic evidence
35
Available data from these studies show that implants based on titanium or
ceramics, are generally well tolerated by the surrounding tissue.

40. 3.MUCOSA AND GINGIVAL USAGE
TESTS
• Materials are placed in cavity preparations with sub gingivalextensions.
• Slight, moderate or severe based on amount of inflammatory cells depending on
the number of mononuclear inflammatory cells (mainly lymphocytes and
neutrophils) in the epithelium and adjacent connectivetissues
• Disadvantages:
• Presence of plaque
• Preexisting inflammation in the gingival tissue
• Surface roughness of the restorative material
• Over contouring and under contouring of therestoration.
40

41. IN USAGE TEST
41
ADVANTAGES
•Relevance to the use of
material is assured
DISADVANTAGES
•Very Expensive
•Time consuming
•Major Legal/ethical concerns
•Can be Difficult to control
•Difficult to interpret and quantify

42. TEST PROGRAMS FOR THEBIOLOGICAL
TESTING OF DENTAL MATERIAL
• Test method describe the manner in which test are to be used.
• The test programs that can be adopted are.
Linear progression of
test
Non-Linear
Progression of test

43. STRATEGIES FOR EVALUATING BIOCOMPATIBILITY
41
• A, the earliest strategy, in which the testing strategy is focused on toxicity only.
Unspecific toxicity refers to tests not necessarily related to the use of the material,
whereas tests under specific toxicity are more relevant. Clinical trials are
equivalent to usage tests in this scheme.
• B, the contemporary strategy used in most standardsdocuments

44. • Disadvantages
• 1. It is seen that the materials that cleared the first two tests were not
entirely harmless at the clinical usagelevel.
E.G. ZOE when tested in vitro completely kills every cell in the
culture, but in clinical practice, the same cement has been
successfully used for many years with no evidence of pulp damage.
• 2. It is time consuming since it is performed in asequential manner.
42

45. NEWER SCHEMES FOR THE PROGRESSION
• A, the pyramid scheme of is retained, but it is acknowledged that primary
and secondary tests will play a continuing (but decreased) role as the
progress of the testing continues.
• B, the usage test has the most stature and the most common progression of
43
tests is from primary to secondary to usage, but the need to go through
several iterations between testing types is acknowledged.

46. supplementary tests to assess the biological reaction to materials.
44
STANDARDS THAT REGULATE THE
MEASUREMENT OF BIOCOMPATIBILITY
• ANSI/ADA SPECIFICATION 41
• This was approved by the council on scientific affairs in 1972 and was
updated in 1982 to include tests for mutagenicity.
• This specification uses the linear paradigm for materials screening and
divides testing into initial, secondary, and usage tests.
• ISO 10993-
• It is the international standards for testing the biocompatibility of dental
materials. It is published in 1992.
• Unlike ANSI/ADA document no. 41, the IS0 10993 standard is not
restricted to dental materials. The standard divides tests into initial and

47. Classification of medical devices according to
Medical Devices Directive

48. Biocompatibility Of Various
Dental Materials
45

49. BONDING AGENTS
46
• May penetrate upto 0.5 mm in dentin and cause
supression of cellular metabolism for upto 4
weeks
• HEMA 100 times less cytotoxic than Bis-GMA
• Release of MMPs from dentin by virtue of
interaction with acid components of dentin
adhesives causes degradation of adhesive bond
by enzymatic action on exposed collagen
within the hybrid layer.
• The application of an MMP inhibitor, such as
chlorhexidine, has been shown to minimize this
effect.

50. RESIN BASED COMPOSITES
47
The dental personnel commonly complain of contact dermatitis
and asthma caused by methacrylates
• Moderate cytotoxic reactions in cultured cells over 24 to 72 hours
of exposure
• Light-cured resins are less cytotoxic than chemically cured
systems highly dependent on the curing efficiency of the
light and the type of resin system.
• The pulpal inflammatory response was low to moderate after 3
days when they were placed in cavities with 0.5 mm of
remaining dentine followed by an increase in reparative dentin .
• With a protective liner or a bonding agent, the reaction of the
pulp to resin composite materials is minimal.

51. Extraoral allergic reactions (type I)
after application of a pit and fissure
sealant
Allergic contact dermatitis of a dentist
after contact with resin-based
composites
48

52. Chemical burn after inadvertent
contact of phosphoric acid with
gingiva
Gingivitis adjacent to a cervical
composite resin filling

53. PRECAUTIONS
• Beneath a composite resin restoration, a suitable base
should be placed to protect the pulp from material
components and bacterial toxins
• Inhalation of composite resin particles during grinding and
shaping of a newly placed restoration should be prevented by
suitable measures such as a rubber dam or the use of
suction/water coolant.
• Protective shields should be attached to the end of the light
guide of polymerization lamps to protect the eyes of dental
personnel
• Dental personnel should always avoid any contact of sk50in or
even gloves with resin-based composites or dentin adhesives,
including during instrument cleaning and waste

54. DENTAL CASTINGALLOYS
51
The biological response to an alloy depends on the biological effects
of released elements, the quantities released, the duration of tissue
exposure to these elements, and other factors
A number of factors influence the corrosion of dental alloys :
• Composition of the alloy (particularly at the surface)
• Surface structure (roughness, presence of oxides)
• Crevices, pits
• Thermal treatment/history
• Combinations of alloys (gold coating, soldering)

55. 52
SYSTEMC
TOXICITY
The number of elements released from the
dental alloys is far below the dietary intake;
for e.g. the amount of zinc released (< 0.1µg
/day ) is far below the daily dietary intake
(14,250µg /day).
No studies have demonstrated
systemic toxicity due to cast alloys
LOCAL TOXICITY When there is a release of elements from the
alloys, and if it is present in more conc. in the
sulcus than in saliva, then epithelial cells of the
sulcus will be more prone to cytotoxicity.
Ni, Cr, Co - Cytotoxic.

56. 53
Allergic
Reactions
The incidence of nickel allergy is 15% and that of
Co and Cr is 8%.
Cross –reactive allergy can occur for Pd and Ni.
Lichenoid reactions have also been reported in
the oral mucosa adjacent to casting alloys.
OTHER
REACTIONS
Vapor form of elements such as beryllium is a
common mutagenic threat.
Beryllium is also a documented carcinogen in
either the metallic or ionic state.
Beryllium-containing particles that are inhaled and
reach the alveoli of the lungs may cause a chronic
inflammatory condition called BERYLLIOSIS

57.  gingivitis due to the PFM crowns;
after removal of the crowns and
seating of temporaryy resin crowns
57

58. Gold coating of nickel-based
and cobalt-based alloys.
58
Pronounced redness of the
palate beneath the denture base.

59. Perioral allergic reaction after insertion
of nickel-containing orthodontic wires
(CuNiTi)
Lichenoid reaction of
the mucosa contacting an alloy
59

60. Pronounced gingivitis after seating
of ceramic crowns, despite good oral
hygiene
Dental lab –Inhaled beryllium –
berylliosis.
60

61. GLASS IONOMER CEMENTS
61
Systemic
Toxicity
No evidence of systemic toxicity with
conventional or resin modified glass ionomer
cement (RMGIC)
Local Toxicity 1. Unset GIC is Cytotoxic to the pulp. The
Cytotoxcity is attributed to the acidity of
the cement and release of fluoride ions .
2. Dentin present between the pulp and the
cement acts like a buffer.
3. Dentin should be moist before the cement
is placed in the prepared cavity.
If dentin is over dried , the cement will
withdraw water needed for the setting
reaction from the dentinal tubules, which will
result in pain.

62. Local
Toxicity
4. RMGIC is cytotoxic in the uncured stage but is only slightly
cytotoxic after curing.
Allergic
reaction
1. Conventional GIC : No reported allergic reaction.
2. RMGIC : Allergy due to HEMA in some individuals. [So wearing
of gloves is recommended to avoid direct contact.]
Other
reactions
1. No evidence of mutagenic or carcinogenic reactions

63. LINERS,VARNISHES,AND NONRESIN CEMENTS
63
• CALCIUM HYDROXIDE
• ZINC PHOSPHATE
• ZINC POLYCARBOXYLATE CEMENT
• ZOE CEMENT

64. CALCIUM HYDROXIDE CEMENT
60
Systemic
toxicity
No reported systemic reaction
Local toxicity Indirect pulp capping material:
1. Exerts antibacterial effect.
2. Tertiary dentin formation.
3.Decreases the permeability of dentin. NOTE:
Tertiary dentin will be triggered only if the
remaining dentin thickness(RDT) is 5 to 10 µm.
Direct pulp capping material: When in direct
contact with the pulp, produces superficial
coagulation necrosis.
This acts like a stimulus for the differentiation of
secondary odontoblasts that lay down tertiary
dentin.

65. ZINC PHOSPHATE CEMENT
65
Systemic toxicity No reported systemic reaction
Local Toxicity The acidity of the cement initially after mixing is very
high due to presence of phosphoric acid (pH is around
3.5 during application).
Subsequently, it increases towards neutrality within
24-48 hours.
Precautions to be taken are as follows:
1. The powder/liquid ratio should never be reduced
to increase the working time, as this increases the
acid content.
2. The placement of a protective layer of a dentin
bonding agent, ZOE, varnish, or calcium
hydroxide is needed.
Allergic Reaction No reported allergic reaction
Other reaction No evidence of mutagenic or carcinogenic reaction

66. Zinc phosphate cement that
was left in the sulcus after
cementation results in
periodontal destruction and
bone loss
66

67. ZINC POLYCARBOXYLATE CEMENT
67
Systemic
Toxicity
No reported systemic reaction.
Local
Toxicity
1. The pH of freshly mixed cement is 3 - 4.
After 24 hours is 5 –6.
2. 2. In spite of the acidic nature of the
cement, it procedures minimal irritation to
the pulp. The reasons for this areas follows:
Liquid is more rapidly neutralized by the
powder I. e its pH rises more rapidly than Zn
phosphate.
3. The poly acrylic acid molecule is larger in
diameter than the dentinal tubules which
limit its diffusion into the tubules

68. ZINC OXIDE EUGENOL CEMENT
64
•
Systemic
toxicity
No reported systemic reaction
Local Toxicity Pulp reaction
1. The cement can produce a cytotoxic
reaction when directly applied to the pulp.
2. If there is a complete dentin layer between
the pulp and the cement, no inflammatory
reaction will occur.
[LEAST IRRITATING OFALL THECEMENTS: pH 6.6 - 8
i.e. Mild pulpal response]
• Eugenol has the capability to blocktransmission
of action potentials of the nerves, hence, this
cement has an obtund ant (soothing) effect when
used in deep cavities.

69. Allergic Reaction Eugenol can induce an allergic response
in some individuals. Allergic contact
dermatitis has also been reported in
dental personnel handling the cement.
Other reaction Eugenol was mutagenic in the
mouse micronucleus test .This
effect could not be reproduced in
transgenic Mice. Based on these
findings, the use of ZOE materials is
not harmful.
69

70. PRECAUTIONS DURING CEMENTATION
70
Apply petroleum jelly to the surrounding soft tissues
Clean the excess cement after luting the prosthesis
Any residues of cement left in the gingival sulcus will lead to
inflammation

71. DENTALCERAMICS
67
SYSTEMIC
TOXICITY
Risk of silicosis among dental technicians due to
inhalation of ceramic dust.
Silicosis is a lung diseases characterized by
shortness of breath, cough, fever, and cyanosis.
Dust removal measures should be followed
in the laboratory.
LOCAL TOXICITY Most ceramics are biocompatible .
ALLERGIC
REACTION
No reported allergic reaction.
OTHER
REACTIONS
Zirconium oxide ceramics show some
amount of radioactivity due to
contaminants such as thorium and
uranium.

72. IMPRESSION MATERIALS
68
Addition Silicone
Hydrocolloids
Polysulphides - contain lead peroxide, among others,
which can cause acute and severe systemic toxic effects
when swallowed or inhaled
Polyether
ZnoE
 least biocompatibility applies to condensation
silicones
NONTOXIC
ALLERGIC REACTIONS

73. • Direct and repeated skin contact by dental personnel, however,
should be avoided.
• Contact with the eyes, which may happen when mixing a liquid
catalyst into a putty impression material by hand, should also be
avoided, such as by wearing protective glasses or by using a paste
catalyst.
• It is important for the subgingival area of the sulcus to be carefully
controlled for remnants of impression material, particularly in
patients with deep periodontal pockets.
69

74. POLY-METHYLMETHACRYLATE RESINS
Denture base materials:
 MMA Monomer is the main
cause for hyper sensitization
• Hypersensitivity has been
documented to the acrylic and
diacrylic monomers, certain curing
agents, antioxidants, amines, and
formaldehyde
• For the patients most of these materials
have been reacted in polymerization
and thus are less prone
• Two aspects are of particular importance:
monomer– polymer conversion and
residual monomer content.
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75. True allergy of oral mucosa to denture base material is very rare
Residual monomer (methyl methacrylate) is believed to be responsible
for allergic reactions in susceptible patients
Allergic acrylic stomatitis – diffuse erythema, edema & occasionally
small vesicles and erosions
 Heat polymerized is better than Autopolymerized resin
75

76. DENTIST SUFFERING FROM AN ALLERGY
TO METHYL METHACRYLATE CONTACT
DERMATITIS
PRONOUNCED INFLAMMATION OF THE
PALATAL MUCOSA BENEATH A POLYMETHYL
METHACRYLATE DENTURE WITH PAPILLARY
HYPERPLASIA
76

77. SOFT DENTURE LINERS & ADHESIVES
 Release of plasticizers
 Extremely cytotoxic
 Denture adhesives show severe
cytotoxic reactions in-vitro
Large amount of formaldehyde
Allowed significant microbial growth
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78. REACTION OF BONE & SOFT TISSUES TO
IMPLANT MATERIAL
A) REACTION TO CERAMIC IMPLANT MATERIAL
VERY LOW TOXICEFFECTS.
OXIDIZED STATE CORROSION RESISTANT
• B) REACTIONS TO RESORBABLE MATERIALS
• Well-tolerated by tissues in vivo
• Resorbability of these materials depends on the volume of material
implanted and because these materials degrade into acidic
byproducts which may invoke an inflammatory response.
• E.G. Co-polymer of polylactic acid (PLA) and polyglycolic acid (PGA), natural
polymers such as cross-linked collagen, starch, andcellulose.
• USED FOR RESORBABLE SUTURES, FRACTURE FIXATION PLATES AND
SCREWS, GUIDED TISSUE MEMBRANES, AND CONTROLLED74
DRUG-
RELEASE SYSTEMS.

79.  C) REACTION TO PURE METALS & ALLOYS
 ‘Metal’ oldest type of oral implantmaterial
 Initially selected on the basis of the ‘ease
of fabrication’
 Stainless steel, chromium-cobalt-
molybdenum, titanium and its
alloys
 Most commonly used is titanium(Ti-6Al-4V)
 Titanium’s biocompatibility is associated
with its fast oxidizing capacity.
 Corrosion resistant & allows osseointegration
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80. SOFT TISSUE :
 Epithelium forms a bond
with implant similar to that of
tooth
 Connective tissue apparently does
not bond to the titanium, but forms
a tight seal that seems to limits
ingress of bacteria & its products
76
In recent years, Titanium
allergy has been noted at a
low prevalence rate of
0.6% and presents with
urticaria, eczema, redness
of the mucosa.

81. BARRIER MATERIALS
Latex :
1.The incidence of latex allergy is about 9.7% and 6% among patients
and dental staff, respectively.
2.Latex products can produce either:
1. Type 1 immediate atopic/anaphylactic reaction - due to proteins
present in natural latex
2.Type 1V delayed hypersensitivity reaction (allergic contact
dermatitis): due to accelerators and antioxidants used in latex
manufacturing.
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82. Precaution to be taken are as follows:
Non latex synthetic materials such as nitrile and styrene ethylene
butadiene styrene should be used.
Polyethylene or polyvinyl chloride rubber dams can be used instead of
latex
•Contact urticaria following
occupational exposure to
latex proteins in disposable
gloves
•severe irritative hand dermatitis (no78n
allergic) caused by frequent hand
washing and wearing of disposable
gloves

83. CONCLUSION
• Due to rise in number of patients with allergies from different materials,
the practicing dentists should be aware about the allergies documented to
known materials
• For establishing diagnosis, it is essential to obtain proper history
related to allergy, clinical examination and confirmatory tests.
• It is mandatory for the clinician to know and understand the
biocompatibility of the dental materials, so as to provide maximum
advantage & minimum risk to the patient.
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84. REFERENCES
87
• Restorative dental materials (13th edition) – G. Craig & John H.
Powers
• Biocompatibility of dental materials –Gottfried Schmalz &
Dorthe Arenholt – Bindslev
• PHILLIPs’Science of dental material (11th edition)

85. 89