2. Outline
Introduction
Definition
Historical background
Biological response in the dental environment
Oral Anatomy That Influences the Biological Response
Special biological interfaces
The oral immune system
Requirement for dental material Biocompatibility
Local and systemic effects of materials
Adverse effects from dental materials
Toxicity
Inflammation
Allergy
Mutagenicity
Key Principles That Determine Adverse Effects from Materials
3. Measuring Biocompatibility
In Vitro tests
Cytotoxicity Tests
Tests for Cell Metabolism or Cell Function
Tests That Use Barriers (Indirect Tests)
Other Assays for Cell Function
Mutagenesis Assays
Animal Tests
Usage Tests
Dental Pulp Irritation Tests
Dental Implants in Bone
Mucosa and Gingival Usage Tests
Correlation Among In Vitro, Animal, and Usage Tests
Using In Vitro, Animal, and Usage Tests together
Standards That Regulate the Measurement of Biocompatibility
ISO 10993
ANSI/ADA Specification 41
Diagnostic tests on patients
4. Classification of biomaterials from perspective of biocompatibility
Biocompatibility of Dental Materials
Reactions of Pulp
-Restorative materials &cements
-Pretreatment& postoperative materials
Root canal filling materials
Reaction of Other Oral Soft Tissues to restorative Materials
Reaction of Bone and Soft Tissues to Implant materials
Reactions to Ceramic Implant Materials
Reactions to Implant Metals and Alloys
Reactions to Resorbable Materials
Materials for short-term Application
Current Biocompatibility issues in dentistry
Measuring the biocompatibility of materials
6. Definition:
The ability of a material to elicit an
appropriate biological response in a
given application in the body.
a single material may not be biologically
acceptable in all applications.
an interaction between the body and
the material
Placement of a material in the body
creates an interface :
dynamic (material body)
between materials and the pulp
(P) via the dentin (D), the
periodontium (PD), the periapical
bone (PA), or the oral cavity (OC)
in general.
7. Interface activity depends on:
- location of material
- its duration in body
- its properties
- health of host
how the material will be used
must be defined.
biocompatibility= color
The biological response will
change if changes occur in the
host, the application of the
material, or the material itself.
8. Historical background:
Using humans as research subjects today without some
previous testing of the biological properties of a material is
unethical and illegal.
Today, the field of biocompatibility testing has reached a
point where some prediction of biological properties is
possible and the future will likely provide the ability to
design materials that elicit customized biological responses.
9. Worldwide, most countries allow the use of only
those dental materials that have successfully
passed a special certification process
11. Oral Anatomy that Influences the
Biological Response
Several aspects of oral anatomy influence the
biocompatibility of dental restorative materials. The
anatomy of the tooth, the periodontal attachment,
and the periapical environment have profound
influences on the biological response to materials,
and all are sites of interface between materials and
tissues in dentistry.
12. The enamel-dentin-pulp environment:
- The enamel:
Permeable to some substances, such
as the peroxides in bleaching agents,
not permeable to material
components, bacteria, or bacterial
products.
- The dentin:
composite nature: dentin bonding.
dentinal tubules: serve as conduits by
which material components, bacteria, or
bacterial products may reach the pulp.
smear layer: decrease permeability but
prevents resin penetration.
13. - The pulp:
Pulp supplies the cells, allows the tooth to
form secondary or reparative dentin.
-The periodontal attachment:
gingival sulcus is a unique
microenvironment
- The periapical area:
the junction of the pulp of the tooth and
the alveolar bone below it. (Endodontic
materials )
15. The implant-bone interface:
A:Osseointegration:
With titanium alloys
(low degradation rates & surface oxides )
B:Biointegration:
with ceramics and ceramic-
Coated metallic implants.
(degradation of the ceramic)
A: approximation must be closer than 10 nm
B:implant and bone are fused and continuous with one
another
16. The oral immune system
The immune system plays an important role in the
biological response to any material. The immune
system in the oral environment appears to behave
somewhat differently in oral epithelium and
connective tissue than in the rest of the body, and
the biological responses to materials in the mouth
may not always parallel to those seen in other
locations.
18. Requirements for dental material
Biocompatibility
1. Should not be harmful to pulp & soft tissues.
2. Should not contain toxic diffusible substances.
3. Should not produce allergic responses.
4. Should not be carcinogenic.
5. Should not be mutagenic.
20. Local effects: are a function
of the ability of substances to be
distributed to these sites, their
concentrations, and exposure
times .
Site: the pulp, peridontium, the
root apex, or buccal mucosa or
tongue.
-inflammation or necrosis
21. Systemic effects: are a
function of the distribution of
substances released from
materials.
Enter the body via ingestion and
absorption in the gut, inhaled
vapor, release at the tooth
apex, or absorption through the
oral mucosa.
( simple diffusion or transport via
the lymphatic or blood vessels).
22. The systemic biological response depends on:
(1) The duration and concentration of the exposure.
(2) The excretion rate of the substance.
(3) The site of the exposure.
24. Toxicity:
Earliest response studied.
Even today, the first screening test used for
almost all materials is a toxicity test.
Earlier material containing LEAD posed a
risk to patient due to toxic property of lead
25. Inflammation:
Histologically, the inflammatory response is
characterized by edema of the tissue with
an infiltration of inflammatory cells.
The contribution of dental materials to
inflammatory reactions is especially
important because pulpal and
periodontal diseases are largely chronic
inflammatory responses to long-term
infections.
26. Allergy:
Allergic reaction occurs when the body
specifically recognizes a material as foreign and
reacts disproportionately to the amount of the
material present.
Type I : immediate atopic or anaphylactic
reaction.
Type II :cytotoxic hypersensitivity reaction.
Type III : immune complex hypersensitivity reaction.
Type IV: delayed hypersensitivity.
27. Allergic Responses to Dental
Materials
1. Allergic Contact Dermatitis
2. Allergic Contact Stomatitis
3. Allergy to Latex products
28. 1. Allergic Contact Dermatitis
Susceptibility & prior
sensitization necessary.
Usually occurs where body
surface makes direct contact
with allergen.
e.g. Monomers of bonding
agent, Acrylic component of
dental cements, nickel & resin
monomers
distal part of fingers & palmer
aspect of fingertips
Allergic contact
dermatitis on the
fingertip of a dentist
after contact with
resin-based
composite
Allergic reaction of
type IV (reaction on
the hands,
distant from the
exposure site) after
exposure to nickel
during an
orthodontic
treatment
29. 2. Allergic Contact Stomatitis
Most common adverse
reaction to Dental Materials.
A) Local/contact type lesions
B) Systemic/distant lesions
Common allergens :- chromium,
cobalt, mercury, eugenol,
components of resin based
materials, & formaldehyde
A:Pronounced
gingivitis of an
orthodontic
patient
(nickel-containing
device)
B:Persisting
perioral and
labial eczema
of an
orthodontic
patient (copper–
nickel–titanium
wires).
30. 3. Allergy to Latex Products
Dermatitis of hand
(eczema) most
common adverse
reaction
Localized rashes &
swelling to wheezing &
anaphylaxis.
31. Mutagenicity:
Mutagenic reactions result when the
components of a material alter the
base-pair sequences of the DNA in
cells.
Several metal ions from dental
materials such as nickel, copper,
and beryllium are known mutagens,
and some components of other
materials such as root canal sealers
have been shown to be mutagenic.
Resin-based materials have been
identified as having some
mutagenic potential.
33. The first factor:
Metal corrosion or Material degradation
Corrosion results in the release of substances from a material
into the host.
the biocompatibility of the material depends to a large
degree on the degradation process.
The biological response to the corrosion products depends
on:
- the amount
- composition
- location in tissues.
34. Corrosion is determined not only by a material's
composition but also by the biological
environment .
For example:
salivary esterases accelerate breakdown of
dental resins.
Ingestion of acidic substances may alter corrosion
of alloys.
35. The second factor :
Surface characteristic
The surface is the part of a material that the body "sees”.
the surface composition, roughness, mechanical properties,
and chemical properties are critical to the biocompatibility
of the material.
36. The surface characteristics influence biocompatibility in
other ways.
For example:
Chemically:- Titanium oxides promote osseointegration
-The surfaces of some materials chemically attract
lipopolysaccharide periodontal inflammation
Rough surface promotes corrosion.
Roughness may also promote the adherence of bacteria and
promote periodontal inflammation
38. In Vitro tests
Cytotoxicity Tests
Tests for Cell Metabolism or Cell Function
Tests That Use Barriers (Indirect Tests)
Other Assays for Cell Function
Mutagenesis Assays
Animal Tests
Usage Tests
Dental Pulp Irritation Tests
Dental Implants in Bone
Mucosa and Gingival Usage Tests
39. In Vitro tests
done outside a living organism
require placement of a material or a component of a
material in contact with a cell enzyme, or some other
isolated biological system
The contact can be either
-Direct: the material contacts the cell system without
barriers
Direct tests subdivided into those in which :
- the material is physically present with the cells
- some extract from the material contacts the cell
system.
-Indirect: a barrier of some sort between the material and
the cell system.
40. Advantages:
1. Quick to perform
2. Least expensive
3. Can be standardized
4. Large-scale screening
5. Good experimental
control
6. Excellence for
mechanisms of interactions
Disadvantages:
1. Relevance to in vivo is
questionable
41. Standardization:
Primary cells:
-taken directly from an animal
and cultured.
-grow for only a limited time.
-retain many of the
characteristics of cells in vivo.
Continuously grown
cells or cell lines:
-have been transformed previously to
allow them to grow more in culture.
- they do retain.
-do not retain all in vivo
characteristics
Two types of cells can be used for in vitro assays.
42. 1.Cytotoxicity Tests:
assess cell death caused
by a material by
measuring cell number or
growth before and after
exposure to that material.
44. 2. Tests for Cell Metabolism or Cell
Function
use the biosynthetic or enzymatic activity of
cells to assess cytotoxic response.
measure (DNA) or protein synthesis
They are analyzed by adding radioisotope
labeled precursors to the medium and
quantifying them on DNA and protein
45. 1. MTT test: (MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-
diphenyl tetrazolium bromide]
Colorimetric assay
MTT is a yellow, soluble molecule
If the cell is able to reduce the MTT
the resulting Formazen formed is
proportional to the enzymatic
activity(Mitochondrial
dehydrogenase)
Formazen quantified by dissolving
it and measuring the optical
density of the resulting solution
alternatively the formazen can be
localized around the test sample
by light or electron microscopy Alive Dead
46.
47. 2. NBT (nitroblue tetrazolium).
3. XTT [2,3-Bis-(2-methoxy-4-nitro-5sulfophenyl)-2H-
tetrazolium-5-carboxanilide salt],
4. WST (a water-soluble tetrazolium)
Other formazen generating chemicals
All being Colorimetric assays based on different
tetrazolium salts.
48. 5. Alamar Blue tests:
quantitatively measure cell
proliferation using a
fluorescent indicator that
allows continuous monitoring
of cells over time.
The amount of fluorescence
produced is proportional to
the number of living cells.
49. 3. Tests That Use Barriers
(Indirect Tests)
Because direct contact often does not exist between cells
and materials during in vivo use, several in vitro barrier tests
have been developed to mimic in vivo conditions.
1. Agar overlay method:
-The cell layer, which has been previously stained
with neutral red (NR), is covered with a thin layer of agar
(A).
-Samples are placed on top of the agar for a time. If the
material is cytotoxic, it will injure the cells and the neutral
red will be released, leaving a zone of inhibition.
50. 2. Millipore filter assay:
Monolayer of cells is grown on a
filter that is turned over so that test
materials are placed on the filter
and leachable diffusion products
are allowed to interact with the
cells.
After exposure, the toxicity in the
Millipore filter test is assessed by the
width of the cytotoxic zone around
each test sample
Material tested
Filter
Cell layer
Cell layer
Filter
51. 3. Dentin disk barrier test method:
-The material is placed on one side of
the dentin disk.
-Collection fluid (cell culture medium
or saline) is on the other side of the
disk.
Components of the material may
diffuse through the dentin and the
effect of the medium on cell
metabolism can then be measured.
52. 4. Other Assays for Cell Function:
These assays measure cytokine production by
lymphocytes and macrophages, lymphocyte
proliferation, chemotaxis, or T-cell resetting to sheep red
blood cells.
The in vivo significance of these assays is yet to be
ascertained, but many show promise for being able to
reduce the number of animal tests required to assess the
biocompatibility of a material.
53. 5. Mutagenesis Assays:
Assess the effect of a biomaterial on a cell’s
genetic material.
1. The Ames test:
Mutant strains of the bacteria
Salmonella tymphimurium were used.
These bacteria contain mutations in the
enzyme that synthesize histidine.
Histidine is responsible for further
synthesis of proteins.
54. 2. Styles’ cell transformation 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.
55. Animal Tests:
Involving mammals such as mice,
rats, hamsters, or guinea pigs.
The use of an animal allows many
complex interactions between the
material and a functioning,
complete biological system to
occur.
56. Advantage:
1. Allows complex
systemic interactions
2. Response more
comprehensive than in
vitro tests
3. More relevant than in
vitro tests
Disadvantages:
1. Relevance to use of
material is questionable
2. Expensive
3. Time consuming
4. Legal/ethical concerns
5. Difficult to control
6. Difficult to interpret and
quantify
57. 1. The mucous membrane irritation test:
Determines whether a material causes inflammation to
mucous membranes or abraded skin.
2. Skin sensitization test:
Materials are injected intradermally to test for development
of skin hypersensitivity reactions, followed by secondary
treatment with adhesive patches containing the test
substance.
Two test methods are recommended using guinea pigs:
The maximization test
The Buehler test
58. The maximization test
Component called the Complete Freund’s
Adjuvant (FCA) is used.
FCA has a tendency to release antigens
steadily.
1. The experimental material is intradermally
injected into the animal with FCA and
evaluated after 7 days.
2. On the 7th day, the same substance is
topically applied for the next 2 days. This
enhances the sensitivity of the tests.
3. After14 days, the skin reactions are
appraised.
59. The Buehler test
This test is very similar to the maximization test. The major
advantage of this test is the elimination of the FCA component.
Buehler test is considered to be more protective for the animals
than the maximization test.
Allergy test on a guinea pig; the
redness of the back
skin is typical of an allergenic
material
60. 3. Implantation tests:
-evaluate materials that will contact
subcutaneous tissue or bone.
-The location of the implantation site may
include connective tissue, bone, or muscle.
-most subcutaneous tests are used for materials
that will directly contact soft tissue during
implantation, as well as endodontic and
periodontal treatment materials.
-Implantation periods can range from 1 week
to many months.
-Inflammation adjoining the implanted material
is evaluated.
Formation of an abscess at
the interface between
material and connective
tissue
61. Usage Tests:
done in animals or in human study participants.
the material is placed in a situation identical to its
intended clinical use.
Fidelity of the test :time, location, environment, and
placement technique.
usage tests in animals usually employ larger animals
that have similar oral environments to humans, such as
dogs, mini-swine or monkeys.
62. Advantage:
1. Relevance to use of
material is assured
Disadvantages:
1. Very expensive
2. Very time consuming
3. Major legal/ethical issues
4. Can be difficult to control
5. Difficult to interpret and
quantify
63. 1. Dental Pulp Irritation Tests:
1. Materials are placed in class 5 cavity
preparations in intact, noncarious teeth.
2. At the conclusion of the study, the
teeth are removed and sectioned for
microscopic examination , with tissue
necrotic and inflammatory reactions
classified according to the intensity of
the response.
Normal pulp inflammed pulp
Modification : teeth with induced
pulpitis, which allow evaluation of the
type and amount of reparative dentin
formed.
64. 2. Dental Implants in Bone:
Three commonly used tests to predict implant
success:
(1) penetration of a periodontal probe along the side of
the implant
(2) mobility of the implant
(3) radiographs indicating either osseous integration or
radiolucency around the implant.
A bone implant is considered successful if it
exhibits:
- no mobility,
- no radiographic evidence of peri-implant radiolucency,
has minimal vertical bone loss and is completely encased
in bone
- absence of persistent peri-implant soft tissue
complications.
65. 3. Mucosa and Gingival Usage Tests:
1. Tissue response to materials with direct contact of gingival and mucosal
tissues is assessed by placement in cavity preparations with subgingival
extensions.
2. An evaluation period of around 7-30 days exists.
3. The material’s effect on gingival tissues are observed
Responses are categorized as slight, moderate, or severe, depending on
the number of mononuclear inflammatory cells in the epithelium and
adjacent connective tissues.
Difficulty : preexisting inflammation in gingival tissue
surface roughness of the restorative material,
open or overhanging margins
over- or under-contouring of the restoration.
66. Correlation Among In Vitro,
Animal, and Usage Tests
In the field of biocompatibility, some scientists
question the usefulness of in vitro and animal
tests in light of the apparent lack of correlation
with usage tests and the clinical history of
materials.
However, lack of correlation is not surprising in
light of differences among these tests.
67. In vitro and animal tests often measure aspects of
biological response that are more subtle or less
prominent than those observed during a
material’s clinical use.
Furthermore, barriers between the material and
tissues may exist in usage tests or clinical use, but
may not exist in the in vitro or animal tests.
Thus, it is important to remember that each type
of test has been designed to measure different
aspects of biological response to a material, and
correlation is not always to be expected.
68. Using In Vitro, Animal, and
Usage Tests together
The most accurate and cost-effective means to
assess biocompatibility of a new material is a
combination of in vitro, animal, and usage tests.
NO single test will be adequate to completely
characterize biocompatibility of a material.
69. Early combination schemes
a pyramid testing protocol
First: “unspecific toxicity” tests
of any type with conditions
that did not necessarily
reflect those of the material’s
use.
Then: specific toxicity tests
with conditions more relevant
to the use of the material.
Finally: a clinical trial of the
material.
70. The contemporary strategy
initial, secondary, and usage
tests.
tests were broadened to
encompass biological reactions
other than toxicity, such as
immunogenicity and
mutagenicity
concept of a usage test in an
animal was also added (versus
a clinical trial in a human).
71. Two newer testing schemes
-First, all tests (in vitro, animal,
and usage) continue to be of
value in assessing biocompatibility
of a material during its
development and even in its
clinical service.
-Second, these new schemes
recognize the inability of current
testing methods to accurately
and absolutely screen in or out a
material.
-Finally, they incorporate the
philosophy that assessing the
biocompatibility of a material is
an ongoing process.
72. Standards That Regulate the
Measurement of Biocompatibility
ANSI/ADA Specification 41
Three categories of tests are
described in the 2005 ANSI/ADA
specification:
initial, secondary, and usage tests.
The ANSI/ ADA specification No. 41, 1982
addendum, added two assays for
mutagenesis— the Ames test and the
Styles’ cell transformation test.
73. ISO 10993
This is the most recent ISO standard available for
biocompatibility testing of dental materials.
The standard divides tests into initial and supplementary tests
to assess the biological reaction to materials.
- Initial tests: are tests for cytotoxicity, sensitization, and
systemic toxicity. Some of these tests are done in vitro, others in
animals in non-usage situations.
- Most of the supplementary tests, to assess things such as
chronic toxicity, carcinogenicity, and biodegradation, are
done in animal systems, many in usage situations.
75. 1) Allergy tests
These tests are further divided as:
• Patch test: Delayed hypersensitivity reactions
• Prick test: Immediate hypersensitivity reaction
• Radioallergosorbent test: Alternative to prick test
• Immunotoxicological test Methods
76. Patch test
• identify delayed type hypersensitivity
(type IV ) as the cause for an allergic contact
dermatitis.
1. Allergens are loaded on to adhesive tapes to
patient’s back.
precautions : sun exposure, increased sweating
or scratching the target area.
The classical signs include redness, itching,
blisters.
2. Skin is evaluated after 2-3 days.
3. A second evaluation after 5-7 days should be
conducted
• Epimucosal…….saliva ???????
77. Prick test:
• detect an immediate-type
allergic reaction or the Type I.
1. The allergen is placed as a
drop on the skin, and the skin is
pierced through the drop.
2. Presence of any positive
reaction is detected after a
period of 5-30 min.
Prick test on the forearm; persons suffering from
a latex allergy frequently show cross-reactions
with various fruits,such as apricots, peaches,
avocados, and bananas.
78. Radioallergosorbent test (RAST)
• in vitro substitute of prick test.
• detect immediate hypersensitivity.
1. The allergen is linked to a material that is insoluble and
the serum taken from the patient is added.
2. The allergen evokes a response by binding to the
antibody if the added serum has antibodies to it.
3. Further on radiolabelled IgE antibody is added, and a
complex reaction occurs with the already linked insoluble
material. IgE antibodies that did not react and form a
complex are washed away.
• It is a quantitative test in the sense, the linked
radioactivity determines the amount of serum IgE
released for a given allergen.
79. Immunotoxicological test
Methods
• mainly for metals
1. lymphocyte transformation test (LTT)
2. memory lymphocyte immunostimulation assay (MELISA)
• still under scientific evaluation. Thus, these methods have
not yet been scientifically approved as routine tests
80. 2) Intraoral voltage:
A metallic taste or a
galvanic shock !!!!!!!!!!!!
This electrical phenomenon
can be measured using
intraoral voltage devices..
81. 3) Evaluation of pulp sensitivity:
demonstrate functional nerval
structures
used for pulp diagnosis and is
mainly based on the application
of cold and of electric current.
Thermal examination by……
A limitation: -only indicate the
presence of functioning nerval
structures.
- cannot be used to prove
vitality or specific inflammatory
reactions of the pulp.
82. 4) Analysis of Intraoral Alloys:
Removable restorations
and dentures
polished metallic micrograph
sections in combination with
energy dispersive x-ray analysis,
or EDX
Fixed restoration
chip test
83. 5) Analysis of Metals in saliva and
Biopsies:
A defined amount of “morning saliva” is collected and,
after chemical pulping, is analyzed, such as by atomic
absorption spectrometry (AAS).
Biopsies, for instance from the gingiva adjacent to
metal restorations, were also used to determine the
metal content. Metal concentrations in biopsies are
usually analyzed by AAS after chemical pulping.
Limitation: extremely difficult to set a reproducible value
for each patient.
88. Bonding Agents
-these reagents are cytotoxic
to cells in vitro if tested alone.
-However, when placed on
dentin and rinsed with water
between applications of
subsequent reagents,
cytotoxicity is reduced.
-A dentin thickness of 0.5 mm
has proven adequate.
90. Resin-Based Materials
• Freshly set Vs 24 hrs. after.
• light-cured resins Vs chemically
cured systems.
• Remaining dentin.
• O2 inhibited layer.
Estrogenicity: Bisphenol A
E-screen assay: relies on growth
response of breast cancer cells
that are estrogen sensitive.
91. Amalgam and Casting Alloys
• corrosion products
• low-copper amalgams
Vs high copper.
• Copper
• Rough or Polished
• Cavity lining Necessary
WHY???????????????
92. Glass Ionomers
• Light-cured ionomer
systems
• The fluoride release:
therapeutic but showed
cytotoxicity in vitro.
• high molecular-sized
polyacrylic acid
93. Liners, Varnishes, and Non-resin Cements
I. Calcium hydroxide cavity liners:
Forms: -Saline suspensions
- Modified forms
suspension Vs cements containing resins
necrosis neutrophils infiltrate into the
subnecrotic zone dystrophic
calcification dentin bridge
formation.
94. II. Resin-based copal varnishes:
No thermal insulation
Not below resins
They may 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
95. III. Zinc phosphate cement:
-thermal conductivity = that of enamel
-Focal necrosis in implantation tests.
- placement of a protective layer .
IV. Zinc polyacrylate cements
(polycarboxylate cements):
release of Zn and fluoride ions +
a reduced pH.
Reparative dentine formation is minimal
with these cements
96. V. ZOE cements:
- ZOE may form a temporary seal
against bacterial invasion.
- Mild, chronic inflammatory
reaction, with some reparative
dentin formation.
100. Endodontic materials
EDTA
- leakage into periapical tissues
during root canal preparation
alter the inflammatory response
of periapical lesions.
-poor antibacterial and
antifungal properties.
101. Sodium hypochlorite
Most complications :
accidental injection beyond
the root apex, which might
cause vigorous tissue reactions
(pain, swelling, and
hemorrhaging).
Conc. 0.5–1%
102. Calcium hydroxide
The best and most
effective intracanal
antibacterial agent.
apical root closure and
bone healing
103. Formocresol
-Tissue irritants and highly toxic.
- Adverse effects………..
-However, in pulpotomy procedures
used in very low concentrations
and in minute quantities, so the
adverse effects might be more
theoretical.
107. Reaction of Other Oral Soft
Tissues to restorative Materials
interproximal areas & under removable appliances.
Cements
Resin composites
Amalgams
108. Casting alloys
Base metal alloys used contain several other non-
noble transition metals, such as Cr, Co, Ni, Mo & Fe,
which might have an adverse effect on cells if they
are released.
Nickel allergy: nickel-based alloys, Stainless steels
Palladium sensitivity: stomatitis, oral lichenoid
reactions
Co–Cr alloys: have an excellent history of
biocompatibility, but there are some reports of tissue
sensitivity.
Ni orthodontic wire
109. Denture base materials (methacrylates):
immune hypersensitivity reactions of gingiva
and mucosa.
dental and laboratory personnel patients
110. Soft denture liners and denture adhesives:
-Significant epithelial
changes, presumably from
the released plasticizers.
-Adhesives also allowed
significant microbial growth.
111. Reaction of Bone and Soft
Tissues to Implant materials:
Reactions to Ceramic Implant Materials:
bioactive & nonbioactive
112. Reactions to Implant Metals and Alloys:
oxide layer
release titanium into
the body
113.
114. Reactions to Resorbable Materials
The materials provoke a physiologic
response to replace the material with
regenerated tissues.
Examples:
resorbable sutures
fixation plates and screws
guided tissue membranes
Resorb-x® plates & meshes
115. Materials for short-term Application
Impression materials
- If unintentionally left.
- Allergy.
123. Defining the Use of a Material
There are several factors that must be
considered when trying to measure the
biological response.
• Location of material
• The duration of material in the body
• Stresses placed on material
124. References
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