biocompatibility of dental materials in prosthodontics

1. BIOCOMPATIBILITY OF DENTAL
MATERIALS
DR. FEBEL HUDA, M.D.S,DICOI,FICOI,FAD,DLD.
ORAL MAXILLOFACIAL PROSTHODONTIST AND IMPLANTOLOGIST
 DIPLOMATE FROM THE INTERNATIONAL CONGRESS OF ORAL
IMPLANTOLOGY
 FELLOW FROM THE INTERNATIONAL CONGRESS OF ORAL
IMPLANTOLOGY
 DIPLOMATE IN LASER DENTISTRY (UNIVERSITY OF GENOVA -
ITALY)
 FELLOW IN AESTHETIC DENTISTRY (UNIVERSITY OF
GREIFSWALD - GERMANY)

2. Introduction

3. ENAMEL
• 96% - Mineralized
• 1% - Organic molecules
 Amelogenins
 Enamelins
• 3% - water
• Orientation of enamel rods gives maximum
strength
• permeability - Y/N
Glycoproteins

4. DENTIN & PULP
• 20% - Organic
85% collagen
Type I collagen
Type V collagen
Type I trimer collagen
Non collagenous dentin;specific proteins
Phosphoryns
Dentin sialoprotein
Dentin matrix protein-1

5. DENTIN & PULP
Non specific proteins
Osteocalcin
osteopontin
• 70% - inorganic
• 10% - aqueous

6. DENTIN & PULP
• Dentinal tubules are surrounded by dentinal
matrix
• Tubules contain odontoblastic processes
• These processes traverse the DEJ & pulp
• Tubules from C.S area range from 20,000/mm²
near DEJ to 50,000/mm² near the pulp.

7. • Tubule diameter varies from 0.5µm at DEJ to 2.5 µm
near pulp
• Pulpal circulation maintains the intercellular
hydraulic pressure of about 24mmHg. (32.5 cm
H20)

8. DENTIN PERMEABILITY
(FLUID CONVECTION)
• Under positive hydraulic pressure-Movement of fluid in
the dentinal tubules stimulates the A-fibers producing
sharp localised pain.
• Under negative hydraulic pressure- fluid convection is
away from the pulp when concentrated solution such
as sucrose, or saturated calcium chloride are exposed
to open dentinal tubules producing sensitivity. Eg,
cervical abrasion.
• Presence of smear layer, cavity liners, sealers, debri can
reduce fluid convection.

9. DENTIN PERMEABILITY
(DIFFUSION)
• Diffusion is proportional to the length of the
dentinal tubules & roughly to the thickness of
dentin between cavity preparation & pulp.
• Ions & molecules can diffuse even against
positive hydraulic pressure.
• Smear layers are better than cavity liners &
sealers.

10. BONE
• Extracellular matrix
23% organic ( 86% type 1 collagen)
77% hydroxyapatite ( smaller & less well formed
than dentin)
Synthesized by osteoblasts ( trapped within
ECM)
Osteocytes on lacunae communicating with
cells in other lacunae through canaliculi (
destroyed- surgery, heat above 45˚C
Osteoclast

11. BIOINTEGRATION
• Ceramic coated implants – better bone
implant interphase
• Eg. Hydroxyapatite, bioglass and tricalcium
phosphate

12. OSSEOINTEGRATION BIOINTEGRATION

13. TERMINOLOGIES

14. ALLERGY
• Allergy is a hypersensitivity disorder of the
immune system.
• The concept of "allergy" was originally
introduced in 1906 by the Viennese
pediatrician Clemens von Pirquet, after he
noted that some of his patients were
hypersensitive to normally innocuous entities
such as dust, pollen, or certain foods.

15. ALLERGY
• In 1963, a new classification scheme was
designed by Philip Gell and Robin Coombs that
described four types of hypersensitivity
reactions, known as Type I to Type V
hypersensitivity
• Type I – Anaphylactic
• Type II – Cytotoxic
• Type III – Immunocomplex
• Type IV – Delayed hypersensitivity
• Type V – Serum sickness

16. MUTAGEN
• Mutagen is a physical or chemical agent that
changes the genetic material, usually DNA, of
an organism and thus increases the frequency
of mutations
• As many mutations cause cancer, mutagens
are typically also carcinogens
• But not all mutagens are carcinogens.

17. CYTOTOXICITY
• Cytotoxicity is the quality of being toxic to
cells. Examples of toxic agents are a chemical
substance, an immune cell or some types of
venom
• (e.g. from the puff adder or brown recluse
spider).

18. MEASURING
BIOCOMPATIBILITY

19. IN-VITRO TESTS
• Outside body
• In vitro – Interaction
of any material on
cell, enzyme or any
biological substance
isolated from
organism.

20. IN-VITRO TESTS
Direct – material physically in
contact with cell
Indirect – extract from the material
in contact with the cell
• Subdivided into measuring
Cell growth / cytotoxicity
Effect on genetic material in cell
Metabolic / other cell function

21. IN-VITRO TESTS
• Advantages
Quick, inexpensive, easy, standardized &
well suited for large scale screening
• Disadvantage
Questionable relevance to final in-vivo
study on same material & lack of
inflammatory and other tissue protective
measures

22. Cell type used in In Vitro studies
• Primary cells – direct from animal into culture
- limited period of growth
- maintains characteristics of cell
- to measure cytotoxicity
• Continuous cells – trasformed primary cells
- growth is in definitive
- no in vivo characterestics
- genetically and metabolically
stable ( easy to standardize)

23. CYTOTOXICITY TESTS
• Assess by measuring the cell number/ growth
after exposing to material
• Liquid- cells are placed in well of culture dish
- then places in sample
- if cell detach and stop growth –
cytotoxic
- if remains in contact with well – non
cytotoxic. Eg; bonding agent,
formocresol

24. CYTOTOXICITY TESTS
• Solid –
eg; Tablets
zone of inhibition

25. CYTOTOXICITY TESTS
Membrane permeability
Na51CrO4
(vital dyes)
Neutral Red
(vital dyes)
Trypan Blue
(non-vital dyes)

26. Membrane permeability
• Usually dyes contain auxochromes
• An auxochrome is a group of atoms attracted
to a chromophore, which are present in cells.
• Vital dyes are basic dyes they contain amino
group, that helps in cell permeability
• The basic dyes bind to negative ions to stain
the cell
• Acid ions in non-vital dyes reduce the ability of
the dyes to stain the vital cells
• Eg – chemicals, injecting drugs

27. TEST FOR CELL METABOLISM /CELL
FUNCTION
• The biosynthesis or enzymatic activity of cells
to assess cytotoxicity
• Measures – DNA synthesis
- Protein synthesis
• They are analyzed by adding radioisotope
labeled precursors to the medium and
quantifying them on DNA and protein
• Radioisotope - 3H-thymidine

28. MTT (4,5-Dimethylthylthiazol) or
CLOSE DYES TEST
• It is a colorimetric
assays
• This measures the
activity of cellular
dehydrogenases
• XTT(2-methoxy-4-
nitro-5-
sulfophenyl),MTS( 4,5-
dimethylthiazol-2-yl),
WST( water soluble
Tetrazolium salt)

29. MTT/CLOSE DYES TEST
• Which converts the MTT chemical to a
purple, insoluble formazan dyes
• If dehydrogenases are not active because of
cytoxic effect the formazan will not form
• Helps in assay the viability & proliferation of
cell
• Quantified using spectrophotometer(500-
600nm wavelength)
• Enzyme that oxidizes a substrate by
transferring hydrogen to an acceptor that is
either NAD(Nicotinamide Adenine
Dinucleotide or a flavin enzyme.

30. TEST THAT USES BARRIERS
(INDIRECT TESTS)
• Since there is no direct contact between cell
and material in vivo ( epithelium/dentin)
• AGAR OVERLAY METHOD:
AGAR NUTRIENTS, GAS, SOLUBLE TOXIC
NEUTRAL RED / FRESH CULTURE MEDIA

31. MILLIPORE FILTERFILTER
CELLULOSE ESTERS
MONOLAYER OF CELLS
1% AGAR
CYTOTOXIC
SOLID OR SOLUABLE TEST SAMPLES
CULTURE MEDIUM

32. DENTIN BARRIER TESTS
Eg; ZOE

34. MUTAGENESIS ASSAYS
• Effect of materials on a cell’s genetic material
• Genotoxic mutagens directly alter the DNA of
the cell through mutation
• Genotoxic chemical may be mutagens in
native state or may require activation or
biotransformation to be mutagens, in which
case they are called promutagens

35. MUTAGENESIS ASSAYS
• Epigenetic mutagens do not alter the DNA
themselves, but support tumor growth by
altering the cell's biochemistry, altering the
immune system, acting as hormones, or other
mechanisms.
• Carcinogenesis is the ability to cause cancer
• Mutagens may or may not be carcinogens,
and carcinogens may or may not be mutagens.

36. AMES TEST
• The test uses several strains of the bacterium
Salmonella typhimurium that carry mutations
in genes involved in histidine synthesis
• It is a auxotrophic mutant, so that they require
histidine for growth.
• The variable being tested is the mutagen's
ability to cause a reversion to growth on a
histidine-free medium
• The plate is incubated for 48 hours
• Eg ; amalgam & drugs

37. AMES TEST

38. STYLE’S CELL TRANSFORMATION TEST
• Non- mammalian test
• This assay quantifies the ability of potential
carcinogens to transform standardized cell
lines so they will grow in soft agar
• Untransformed fibroblasts normally will not
grow within an agar gel, whereas genetically
transformed cells will grow below the gel
surface

39. ANIMAL TESTS

40. ANIMAL TESTS
• Mammals such as mice, rats, hamsters, or
guinea pigs, although many types of animals
have been used.
• The use of an animal allows many complex
interactions between the material and a
functioning, complete biological system to
occur.

41. ANIMAL TESTS
Advantage :
• The biological responses in animal tests are
more comprehensive and may be more
relevant than in vitro tests
Disadvantages :
• they can be difficult to interpret and control,
are expensive, may be time consuming, and
often involve significant ethical concerns and
paperwork.

42. MUCOUS MEMBRANE IRRITATION
TEST

43. SKIN SENSITIZATION TEST
Dermal patch will be
used after injection

44. DECISION – POINT APPROACH
• tests are applied in a specific order, and
testing is stopped when anyone indicates
mutagenic potential of the material or
chemical

45. IMPLANTATION TEST
• To evaluate materials that will contact
subcutaneous tissue or bone.
• Amalgams and alloys are tested because the
margins of the restorative materials contact
the gingiva.

46. SHORT TERM IMPLANTATION
Polyethylene tubes Test material
1 – 11 weeks

47. LONG TERM IMPLANTATION
Polyethylene tubes Test material
1 – 11 weeks
1 – 2 years

48. USAGE TEST
• Usage tests may be done in animals or in
human volunteers.
• The material be placed in a situation identical
to its intended clinical use
• Larger animals that have similar oral
environments to humans, such as dogs or
monkeys are used.

49. USAGE TEST
Disadvantages
• These tests are extremely expensive, last for
long periods, involve many ethical and often
legal concerns, and are exceptionally difficult
to control and interpret accurately.

50. DENTAL PULP IRRITATION TESTS
TEST MATERIAL PLACED
ZOE
After treatment the tooth is extracted and examined
under a microscope and a photomicrometer
the thickness of reparative dentin is measured

51. DENTAL IMPLANT INTO BONE
• Failure of implants are gained from three
tests:
(1) penetration of a periodontal probe along
the side of the implant,
( 2 ) mobility of the implant, and
(3) radiographs indicating either osseous
integration or radiolucency around the
implant.

52. DENTAL IMPLANT INTO BONE
• Implant is considered successful if it
exhibits no mobility,
no radiographic evidence of peri-implant
radiolucency,
minimal vertical boneloss,
absence of persistent peri-implant soft tissue
complications
• Fibrous capsule formation is a sign of irritation
and chronic inflammation.

53. MUCOSA AND GINGIVAL USAGE TESTS
• Materials are placed in cavity preparations
with subgingival extensions.
• observed at 7 days and again after 30 days.
• Responses are categorized as slight, moderate,
or severe.

54. MUCOSA AND GINGIVAL USAGE TESTS
• A slight response is characterized by a few
mononuclear inflammatory cells (mainly
lymphocytes) in the epithelium and adjacent
connective tissue.
• A moderate response is indicated by
numerous mononuclear cells in the
connective tissue and a few neutrophils in the
epithelium.

55. MUCOSA AND GINGIVAL USAGE TESTS
• A severe reaction evokes a significant
mononuclear and neutrophilic infiltrate and
thinned or absent epithelium.

56. MUCOSA AND GINGIVAL USAGE TESTS
• Difficulties
degree of preexisting inflammation in gingival
tissue
the surface roughness of the restorative
material
overcontouring or undercontouring of the
restoration.
• 8 – 14 days of healing time should be given
after oral prophylaxis.

58. USING IN VITRO, ANIMAL, AND USAGE
TESTS TOGETHER

59. USING IN VITRO, ANIMAL, AND USAGE
TESTS TOGETHER

60. STANDARDS THAT REGULATE
THE MEASUREMENT OF
BlOCOMPATlBlLlTY
• 1926 - the National Bureau of Standards,
now as the National Institute of Science and
Technology, developed specifications for dental
amalgam.
• But failed –
(1) the fast advance of cellular and molecular
biology,
(2) the variety of tests available for assessing
biocompatibility of materials,
(3) the lack of standardization of these tests.
J Dent Res 81(10):660-663, 2002

61. STANDARDS THAT REGULATE
THE MEASUREMENT OF
BlOCOMPATlBlLlTY
• Dixon and Rickert in 1933 - investigated by
implanting the materials into pockets in sub-
dermal tissue.
• Material checked were - gold, amalgam, gutta-
percha, silicates, and copper amalgam.
• Massler (1958) on tooth pulp.
• Mitchell (1959) on connective tissue
J Dent Res 81(10):660-663, 2002

62. STANDARDS THAT REGULATE
THE MEASUREMENT OF
BlOCOMPATlBlLlTY
• 1972 – The Council on Dental Materials,
Instruments, and Equipment of ANSI/ADA
approved Document No. 41 for
Recommended Standard Practices for
Biological Evaluation of Dental Materials.
• 1972 - NIOM (Nordisk Odontologisk Material
prøvning) was founded by the Nordic in
Europe
J Dent Res 81(10):660-663, 2002

63. STANDARDS THAT REGULATE
THE MEASUREMENT OF
BlOCOMPATlBlLlTY
• 1976 - Medical Device Bill by Congress,
biological tested for all medical devices
(including dental materials) given a high
priority.
• In 1982 - an addendum was made to this
document, including an update of the Ame’s
test for mutagenic activity.
J Dent Res 81(10):660-663, 2002

64. ANSI/ADA Document 41
• Three categories of tests are described in the
1982 ANSI/ADA document: initial, secondary,
and usage tests.
J Dent Res 81(10):660-663, 2002

65. ANSI/ADA Document 41
• Primary tests - in vivo acute physiological distress
and death at the level of the whole organism.
• secondary tests - In small animals (in vivo) for
inflammatory or immunogenic potential (e.g.,
dermal irritation, subcutaneous and bony
implantation, and hypersensitivity tests).
• usage tests - (placement of the materials in their
intended contexts, first in larger animals, often
primates, and finally, with Food and Drug
Administration approval, in humans).
J Dent Res 81(10):660-663, 2002

66. IS0 10993
• The final document (IS0 10993) was published
in 1992 and is the most recent standard
available for biological testing.
• IS0 10993 contains 12 parts, each dealing with
a different aspect of biological testing
J Dent Res 81(10):660-663, 2002

67. IS0 10993
• part 2- addresses animal welfare
requirements,
• part 3 - addresses tests for genotoxicity,
carcinogenicity, and reproductive toxicity, and
part 4 deals with tests for interactions with
blood.
J Dent Res 81(10):660-663, 2002

68. IS0 10993
• The standard divides tests into "initial“ and
"supplementary" tests
• Initial tests - cytotoxicity, sensitization, and
systemic toxicity.
• Supplementary - chronic toxicity,
carcinogenicity, and biodegradation.
J Dent Res 81(10):660-663, 2002

69. BIOCOMPATIBILITY OF DENTAL
MATERIALS
REACTIONS ON PULP AND OTHER
ORAL TISSUES

70. MIRCOLEAKAGE
• Contraction on polymerization, wear, or
thermal cycling.
• Amalgam, composite, zincphosphate cement,
and silicate cement
TEST MATERIAL PLACED
ZOE

71. NANOLEAKAGE
• The leakage of saliva, bacteria, or material
components through the interface between a
material and tooth structure.
• nanoleakage refers specifically to dentin
bonding, and may occur between mineralized
dentin and a bonded material in the very
small spaces of demineralized collagen matrix
into which the bonded material did not
penetrate.

73. DENTIN BONDING
• Bonding to dentin has proven more difficult
because of its composition (being both
organic and inorganic), wetness, and lower
mineral content.

74. SMEAR LAYER
• 1- to 2-µm layer of organic and inorganic
debris.
• It was said to be impermeable but diffusion of
molecules as large as albumin (66 kDa) has
occurred through a smear layer.
• Ethylenediaminetetraacetic acid (EDTA),
sodium hypochlorite, and proteolytic
enzymes.

76. DENTIN BONDING
• Successful bonding agents are able to
penetrate into the layer of collagen that
remains after acid etching, creating a "hybrid
layer" of resin and collagen in intimate contact
with dentin and dentinal tubules
• The removal of the smear layer makes any
microleakage more significant

77. DENTIN BONDING
• The acids used to remove the smear
layer are a potential source of irritation
themselves (phosphoric,
hydrochloric,citric, and lactic acids).
• Dentin is a very efficient buffer of
protons, and most of the acid may never
reach the pulp if sufficient dentin
remains.

78. DENTIN BONDING
• A dentin thickness of 0.5 mm has proven
adequate.
• Citric or lactic acids are less well buffered

80. Restorative and lining materials

81. DENTIN BONDING AGENTS
• Many of dentin bonding agents are cytotoxic
to cells in vitro tested alone.
• But when placed on dentin and rinsed with
tap water between applications of subsequent
reagents as prescribed, cytotoxicity is often
reduced.

82. DENTIN BONDING AGENTS
• Bonding agents permeate up to 0.5 mm of
dentin to cause significant suppression of
cellular metabolism
• Hydroxyethyl methacrylate (HEMA), a
hydrophilic resin contained in several bonding
systems, is at least 100 times less cytotoxic in
tissue culture than Bis-GMA.

83. DENTIN BONDING AGENTS
• However, if the dentin in the floor of the
cavity preparation is thin (< 0.1 mm), there is
some evidence that HEMA may be cytotoxic in
vivo.
• Eg; 1st generation, 2nd generation, 3rd
generation, 4th generation.

84. COMPOSITE RESIN
• Freshly set chemically cured and light-cured
resins often cause moderate cytotoxic
reactions in cultured cells
• The cytotoxicity is significantly reduced 24 to
48 hours after setting and by the presence of a
dentin barrier.

85. COMPOSITE RESIN
• The light-cured resins are less cytotoxic than
chemically cured systems
• The pulpal inflammatory response to
chemically cured and light-cured resin
composites is low to moderate after 3 days
when they were placed in cavities with
approximately 0.5 mm of remaining dentin.

86. COMPOSITE RESIN
• It is very cytotoxic in in-vitro tests of direct
contact with fibroblasts
• Probably because of unpolymerized
components in the air-inhibited layer that
leach out from the materials.
• Some of the newer composites with non-
BisGMA non-UDMA matrices have
significantly lower cytotoxicity

87. COMPOSITE RESIN
• Polished composites show markedly less
cytotoxicity in vitro.
• bis-phenol-A and bis-phenol-A dimethacrylate
to cause estrogen-like responses in vitro.
• The effect on other oral tissues is not
significant

90. AMALGAM
• Biocompatibility of amalgam is determined
largely by corrosion products released while in
service.
• Unreacted mercury from amalgam is toxic, but
low-copper amalgam that has set for 24 hours
does not inhibit cell growth.

91. AMALGAM
• Implantation tests show that low-copper
amalgams are well tolerated than high copper.
• The cavity preparation should be lined for two
other reasons
1. Thermal conductivity with amalgam
2. Margins of newly placed amalgam
restorations show significant microleakage

92. AMALGAM
• Amalgam restorations carried into the gingival
crevice causes inflammation of the gingiva
because of products of corrosion or bacterial
plaque
• Even after 7 days after placing an amalgam, a
few inflammatory cells appear in the gingival
connective tissue, and hydropic degeneration
of some epithelial cells may be seen.

93. AMALGAM
• Although copper enhances the physical
properties of amalgam and is bactericidal, it is
also toxic to host cells and causes severe
tissue reactions in implantation tests.
• gallium-based alloys that have been used as
amalgam replacements also shows sever
reactions.

94. Amalgam and Resin
composite restorations
(miracle mix)
• The cavities, with depths of about 2 mm, were
placed halfway between the cementoenamel
junction and the root tip.
• The teeth were immediately reimplanted after
restoration

95. miracle mix
• The animals were sacrificed at intervals up to 6
months. Repair of the PDL took place in a
normal fashion except for the presence of an
intense inflammatory infiltrate in the PDL
adjacent to the amalgams through 2 weeks,
but to the resin composites through 3 to 6
months.
• This result suggests that resin composites and
amalgam release cytotoxic materials

96. AMALGAM
• In- vivo : Materials placed where they are
rinsed in saliva, these cytotoxic agents are
probably washed away before they harm the
gingiva.
• rough surfaces on alloy restorations also
caused increased cytotoxic effects so polishing
the restoration is important.

98. GLASS IONOMERS
• Glass ionomers are another type of material that
have been used both as a cement (luting agent)
and as a restorative material.
• Freshly prepared ionomer is mildly cytotoxic, but
this effect is reduced with increased times after
setting.
• The fluoride release from these materials, which
is probably of some therapeutic value, causes
cytotoxicity in in vitro tests

99. GLASS IONOMERS
• Histological studies in usage tests shows that
any inflammatory infiltrate from ionomer is
minimal or absent after 1 month.
• There have been several reports of pulpal
hyperalgesia for short periods (days) after
placing glass ionomers in cervical cavities.
• This effect is probably the result of increased
dentin permeability after acid etching or the
high pH of the restoration.

101. CALCIUM HYDROXIDE
• Cavity liners of two basic type
saline suspensions with a very alkaline pH
(above 12)
modified forms containing zinc oxide,
titanium dioxide, and resins.
• The high pH of calcium hydroxide in
suspension leads to extreme cytotoxicity

102. CALCIUM HYDROXIDE
• Calcium hydroxide cements containing resins
cause mild-to-moderate cytotoxic effects.
• The inhibition of cell metabolism is reversible
in tissue culture by high levels of serum
proteins, suggesting that protein binding or
buffering in inflamed pulpal tissue may play an
important role in detoxifying these materials
in vivo.

103. CALCIUM HYDROXIDE
• The initial response is necrosis to a depth of 1
mm or more, neutrophils infiltrate into the
subnecrotic zone.
• Eventually, after 5 to 8 weeks, only a slight
inflammatory response remains.
• Within weeks to months, the necrotic
• zone undergoes dystrophic calcification, which
appears to be a stimulus for dentin bridge
formation

104. CALCIUM HYDROXIDE
• When resins are incorporated into the
formulae, these calcium hydroxide
compounds become less irritating and are
able to stimulate reparative dentin bridge
formation more quickly than the Ca(OH),
suspensions, and with no zone of necrosis.

105. LINERS
Copal varnish
• These materials are not generally used under
resin-based materials, because resin
components dissolve the thin film of varnish.
• Since liners are used in such thin layers, they
do not provide thermal insulation, but they
initially isolate the dentinal tubule contents
from the cavity preparation.

106. LINERS
Copal varnish
• They may also reduce penetration of bacteria
or chemical substances for a time.
• Because of the thinness of the film and
formation of pinpoint holes, the integrity of
these materials is not as reliable

107. ZINCPHOSPHATE
• The thermal conductivity of this cement is
approximately equal to that of enamel
• zinc-phosphate cement elicits strong-to-
moderate cytotoxic reactions that decrease
with increased time after setting.
• Focal necrosis, observed in implantation tests

108. ZINCPHOSPHATE
• In usage test , moderate-to-severe localized
pulpal damage is produced within the first 3
days, probably because of the initial low pH
on setting (4.2 pH at 3 minutes)
• The pH of the set cement approaches
neutrality after 48 hours

109. ZINCPHOSPHATE
• Because of the initially painful and damaging
effects on the pulp of this cement when
placed in deep cavity preparations, the
placement of a protective layer of a dentin
bonding agent, ZOE, varnish, or calcium
hydroxide is recommended under the cement.

110. ZINCPHOSPHATE
• Other formulae have included calcium
hydroxide in the powder, lowering the
concentrations of phosphoric acid in the
liquid, or included materials such as copper
and fluoride ions that may function as
antimicrobial agents.
• copper ions have proven extremely toxic in
implantation tests

111. ZINC POLYCARBOXYLATE
• Developed to combine the strength of zinc
phosphate cements with the adhesiveness
and biocompatibility of zinc oxide eugenol
(ZOE).
• Inhibition of cells is seen initially but
decreases as the cement sets.
• Pulpal response similar to that caused by ZOE,
with a slight-to-moderate response after 3
days and only mild, chronic inflammation after
5 weeks.
• Reparative dentin formation is minimal

112. ZINC OXIDE EUGENOL (ZOE)
• ZOE fixes cells, depresses cell respiration, and
reduces nerve transmission with direct
contact.
• ZOE has been reported bactericidal.
• This lower concentration reportedly
suppresses nerve transmission and inhibits
synthesis of prostaglandins and leukotrienes
(anti-inflammatory)

113. ZINC OXIDE EUGENOL (ZOE)
• Usage tests - ZOE caused only a slight-to-
moderate inflammation in first week,
• And reduced to a mild, chronic inflammatory
reaction.
• Reparative dentin formation in 5 to 8 weeks.

114. Non – Restorative Materials

115. DENTURE BASE MATERIAL
• Methacrylates, have been associated with
immune hypersensitivity reactions of gingiva
and mucosa probably more than any other
dental material.
• dental and laboratory personnel are in high
risk exposed repeatedly to a variety of
unreacted components.
• Visible light-cured denture base resins and
denture base resin sealants have been shown
to be cytotoxic to epithelial cells in culture.

118. SOFT DENTURE LINERS
• Cell culture tests : have shown that some of
these materials are extremely cytotoxic
• In animal tests : caused significant epithelial
changes
• In usage : Mild cytotoxity

119. DENTURE ADHESIVES
• severecytotoxic reactions.
• The adhesives also allowed significant
microbial growth

120. IMPLANT MATERIAL
• There are four basic materials used in implant
fabrication: ceramics, carbon, metals, and
polymers (and combinations of the above).
• Have low toxicity, and are nonimmunogenic
and noncarcinogenic.

121. IMPLANT MATERIAL
• Carbon has been used as a coating and in bulk
forms for implants. Although the biologic
response to carbon coatings can be favorable,
they have been supplanted by titanium,
aluminum oxide bulk materials, and
hydroxyapatite coatings
• Although titanium and titanium alloy implants
have corrosion rates that are markedly less
than other metallic implants, they do release
titanium into the body.

122. CASTING ALLOYS
• They have generally good record of
biocompatibility
• HYPERSENSITIVITY: Nickel ( 10% - 20%)
females, palladium.
• CARCINOGENIC: beryllium, cadmium,
cromium(Cr6), nickel subsulfide (Ni2S3)
• MUTAGEN: Tin, copper, iron
Dental materials 18 (2002) 413-421

127. POLYSULFIDE RUBBER IMPRESSION
MATERIAL
• ADA measured toxicity by injecting material
into the oral mucosa of baboons for 48 h
• light-bodied materials were less toxic and
contained less lead, toxicity was not strongly
related to lead content.
• lead peroxide (PbO2) are used in materials for
radiographic detection.
J Dent Res 62(5):548-55 1, May 1983

128. POLYSULFIDE RUBBER IMPRESSION
MATERIAL
• But makes it difficult to distinguish from
coagulated blood.
• The method
• determined that Sta-tic X and Imprex are
significantly more toxic but the lead content
had no significant result.
J Dent Res 62(5):548-55 1, May 1983

130. BLEACHING AGENT
• These agents usually contain some form of
peroxide (generally carbamide peroxide) in a
gel that can be applied to the teeth either by
the dentist or at home by the patient.
• The agents may be in contact with teeth for
several minutes to several hours depending on
the formulation of the material.
• Home bleaching agents may be applied for
weeks to even months in some cases

131. BLEACHING AGENT
• In vitro studies have shown that peroxides can
rapidly (within minutes) traverse the dentin in
sufficient concentrations to be cytotoxic.
• But the cytotoxicity depends to a large extent
on the concentration of the peroxide in the
bleaching agent

132. BLEACHING AGENT
• Peroxides rapidly even penetrate intact
enamel and reach the pulp in a few minutes.
• Tooth sensitivity is very common with the use
of these agents

134. LATEX
• It was only in 1980 dentists started using
gloves.
• In March 29, 1991, the FDA issued a bulletin in
response to latex related allergy.
• Latex is made from the white milky sap from a
rubber tree.
• Ammonia is added to the sap as preservative,
this produces allergy.
• Latex is soaked is hot water to remove the
allergent but this just brings it to the surface.

136. REFERENCE
• Craig RG, Restorative dental materials, 10th ed.
• Gottfried schmalz, Biocompatibility of dental
materials, 3rd ed,2009.
• Wataha JC: Biocompatibility of dental casting
alloys: a review, J Prosthet Dent 83:223, 2000.
• deSouza Costa CA, Beling J, Hanks CT: Current
status of pulp capping with dentin adhesive
systems: a review, Dent Mater 16:188, 2000.

137. REFERENCE
• D.B. Mahler; The High-copper Dental Amalgam
Alloys; J Dent Res 76 (1) 1997
• H.A. Lyttle and G.H. Bowden; The Level of
Mercury in Human Dental Plaque and Interaction
in vitro between Biofilms of Streptococcus
mutans and Dental Amalgam; J DENT RES 1993
72: 1320.
• Werner Geurtsen; Toxicology of Dental Materials
and 'Clinical Experience'; J DENT RES 2003 82:
500.

138. REFERENCE
• Cox CF, Keall CL, Keall HJ, Ostro EO:
Biocompatibility of surface-sealed dental
materials against exposed pulps, J Prosthet
Dent 57:1, 1987.
• T.J. Spranley, Acute Tissue Irritation of
Polysulfide Rubber Impression Materials, J
DENT RES 1983 62: 548.
• Gottfried Schmalz, Materials Science:
Biological Aspects, J DENT RES 2002 81: 660

139. REFERENCE
• Y. Kawata, Cytotoxicity of Pd-Co Dental Casting
Ferromagnetic Alloys, J DENT RES 1981 60:
1403.
• G.M. Brauer, Development of High-strength,
Acrylic Resin-compatible Adhesive Cements, J
DENT RES 1983 62: 366
• Y.-L. Lee, Effects of EDTA on the Hydration
Mechanism of Mineral Trioxide Aggregate, J
DENT RES 2007 86: 534

140. REFERENCE
• Daniel A. Garcia, The Biocompatibility of
Dental Implant Materials Measured in an
Animal Model, J DENT RES 1981 60: 44
• D.B. Mahler, The High-copper Dental Amalgam
Alloys, J DENT RES 1997 76: 537

141. THANKYOU