5. Measuring biocompatibilty
Invitro test
Animal test
Usage test
Using invitro,animal and usage tests together
Selection of biocompatible material
Biocompatibility of dental materials
Review of literature
Conclusion
Reference
5
6. “Our objective should be the perpetual
preservation of what remains rather than
the meticulous restoration of what is
missing”
MULLAR M.DE VAN
6
8. Although the concept of the ethical treatment of
patients extends back to the time of Hippocrates (460-
377 KC.), the idea that new dental materials must be
tested for safety and efficacy before clinical use is
much more recent.
As late as the mid 1800s,dentists tried new materials
for the first time by putting them into patients'
mouths.
9. Many exotic formulations were used. For example,
Fox developed a "fusible metal“ that consisted of
bismuth, lead, and tin, which he melted and poured
into the cavity preparation at a temperature of
approximately 100" C.
Even G.V. Black used patients to test many of his new
ideas for restorative materials, such as early
amalgams.
10. The current philosophy about testing the biological
properties of dental materials in a systematic way
evolved in the 1960s as the need to protect patients
became politically acute and as the number of new
materials increase.
The concept of protecting the patient as a research
subject is only 30 to 40 years old, and many of the
regulations and ethics in this area still being
challenged and defined today.
11. Dentists potential concerns about biocompatibility can be
organized in to 3 areas :
1) Safety of the patient.
Primary concern - avoid any harm to the patient.
2) Safety of Dental staff
The risk of adverse effects of biomaterials is much higher
for dental staff than for the patient. The staff may be chronically
exposed to materials when they are being manipulated or setting.
Eg:- i) Amalgam – Mercury vapour.
ii) Chronic exposure to latex and resin based materials.
11
12. iii) Regulatory compliance issues
Biocompatibility issues are closely linked to regulations that
affect dental practice.
Ex: Dental amalgam.
3) Legal Liability.
Biocompatibility issues also influence liability issues that affect
dental practitioners.
12
13. Two regulations currently govern the use of dental materials:
ANSI/ADA document No.41(1979) & addendum
No41A(1982)
ISO10993document(1993) although these documents are
different , ANSI/ADA document is currently under
revision to coordinate with the ISO document.
13
14. Biocompatible
Capable of existing in harmony with surrounding
biological environment
GPT(9)
Biocompatibility
Property of the material which remain harmoniously with the
living tissues.
Shama Bhat-2nd edition
Ability of a material to elicit on appropiate biological response
in a given application in the body.
Craig -12 edition
14
15. Biomaterial
Any substance other than a drug that can be used for
any period of time as part of a system that treats, augments, or
replaces any tissue, organ, or function of the body.
GPT(8)
Bioinert
These allow close apposition of bone on their surface
leading to intact osteogenesis.
Metals –commerically pureTi
Ti alloy (Ti6Al-4V)
Al2O3,Zr2O3
15
16. Biodegradation
The series of processes by which living systems render
chemicals less noxious to the environment.
GPT(8)
Bioactive
Having an effect on or causing a reaction in living tissue
16
17. Should not be harmful to pulp and soft tissues
Should not contain toxic diffusible substance
Should not produce allergic responses
Should not be carcinogenic
Should not undergo biodegradation
Should not show estrogenecity and contain xenoestrogens
17
19. Paracelus(1493-1541)- father of toxicology and first
modern medical scientist said that.
“All things are poison and nothing is without poison only
the dose permits something not to be poisonous”.
Latter phrase-right dose differentiates a poison for remedy.
19
20. Test organism such as cells and selected bacteria through
higher order plants and animals.
A specific response or biological endpoint.
Exposure or test period.
A dose or dose curve.
20
21. 21
Hypersensitivity is abnormal reaction
that occurs when the body is exposed
to a foreign material.
Develops only in person whose
immune system recognise the material
as foreign.
Allergic reaction can manifest as a
localised reaction in tissues which is
directly in contact with material.
Systemic manifestation are skin
eruption, itching, sneezing,
erythema,breathing difficulties.
25. Altering the base pair sequence of DNA in cells
Resin based restorative
Sealants
Ions of metal(Ni,Be,Cu) found to be mutagens.
25
26. Ability to produce material like xenoestrogens to act in
body as estrogens
Resin
bisphenolA-starting substance of BisGMA
Restorative material and few other resin are estrogenic
26
27. 27
Osseointegration –formation
of living body tissues within
10mm space from the
implant material surface
without any fibrous
connective tissues.
Material –CpTi,Ti6Al-4v
alloy,tantalum and few
ceramics.
These material does not
undergo biodegradation
easily.
28. Certain material like bioglasses which undergo
biointegration with the bone.
Directly without any interviewing space.
This material should undergo degradation.
28
29. 29
Alteration in cells of
immune system.
Mercury
Palladium
Dentin bonding agents
HEMA may indirectly
cause change in cellular
function.
31. 31
• Highly mineralised.
• More brittle than dentin.
• Solubilised to a greater extent by acid solution.
• Helps for bonding agents to provide micromechanical
retention.
32. Essential of Oral Histology and Embrology A Clinical Approach-James k Avery|Daniel j ChiegJ-Mosby
Elsevier
32
33. Essential of Oral Histology and Embrology A Clinical Approach-James k Avery|Daniel j ChiegJ-Mosby
Elsevier 33
34. 34
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.
35. 35
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.
36. Extacellular matrixwith cells and tissues .
Mineralised tissue-23%organic substance (86%typeI collagen)
77%hydroxyapatite(small and less well dentin)
Vascularity of bone serve mineral phase as a major reservoir
of calcium and phosphate ions for body’s metabolic processes.
Synthesized by osteoclast .
It have excellent self repair capacity.
36
38. 38
Consist of PDL,cementum and
alveolar bone.
Cementum and alveolar bone –
extracellular matrices.
Cells are destroyed during injury
and have no source of progenitor
cells ankylosis –bone and teeth
Researchers have investigated that
chemical and surgical methods to
limit epithelial down growth of
gingiva to enhance PDL
reattachments to tooth and bone
surface,
39. Gingiva –attached and free gingiva.
Oral mucosa –loose fibroelastic connective tissuewith a well
vascularised and innervated lamina propria and submucosa and
covered by parakeratinized stratified squamous epithelium.
Dental material chemically and physically injury OMM
Gingival tissues reaction to oral implant.
39
40. Transmucosal implant –special problem-epithelial
growth,encystification and exfoliation of implant.
Inflammatory disease around implant is implantits.
Perimplantitis-response to bacteria that attached to
implant and exist near the gingiva.
40
42. Outside body
In vitro – Interaction of any
material on cell, enzyme or
any biological substance
isolated from organism.
42
43. 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
43
44. Advantages
Quick
Inexpensive
Easy
Standardized
Well suited for large scale screening
Disadvantage
Questionable relevance to final in-vivo study.
Lack of inflammatory and other tissue protective
measures.
44
45. Primary cells – direct from animal into culture
- limited period of growth
- maintains characteristics of cell
- to measure cytotoxicity
Continuous cells – transformed primary cells
- growth is in definitive
- no in vivo characteristics
- genetically and metabolically
stable ( easy to standardize)
45
46. 46
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
49. 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
49
50. 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
50
51. 51
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)
52. 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.
52
53. 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
53
54. 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
54
55. 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.
55
56. 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
56
58. 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
58
60. 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.
60
61. Advantage :
More comprehensive.
More relevant than in vitro tests.
Disadvantages :
Difficult to interpret and control
Expensive
Time consuming
Significant ethical concerns
Paperwork.
61
62. 62
Material causes inflammation to mucous
membrane or abraded skin.
Postive and negative controls are placed in
contact with hamster cheek pouch tissue
or rabbit oral tissue.
Several week later it is examined and
gross tissue reaction in living animals are
recorded.
Animal sacrificed and biopsy specimen
are prepared for histological evaluation.
63. Guinea pigs –intradermally test solution is injected for
development of skin hypersensitivity reaction.
Result-no reaction to redness and swelling.
63
64. Tests are applied in a specific order, and testing is stopped
when anyone indicates mutagenic potential of the material
or chemical.
64
65. 65
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.
Short term tests ( 12 weeks)
Mice, rats, guinea pigs
Long term tests ( Weeks) dogs,
rabbits, sheep, goats.
66. 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.
66
67. Advantages
Relevance to use of material is assured
Disadvantages
Very expensive
Very time consuming
Major legal/ethical issues
Can be difficult to control
Difficult to interpret and quantify
67
68. Monkeys are suitable animal.
Class V cavity preparation done with minimal trauma.
ZOE and silicate cements used with positive and negative
control material respectively and left for 1-8 weeks.
Tooth is removed and examined under microscope and a
photomicrometer for reparative dentin evaluation.
68
69. Failure of implants are gained from three tests:
Periodontal probing
Mobility
Radiolucency around the implant.
69
70. 70
Implant is considered successful if
it
No mobility
No peri-implant radiolucency
Minimal vertical bone loss
Absence of persistent peri-implant
soft tissue complications
Fibrous capsule formation is a
sign of irritation and chronic
inflammation.
71. 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.
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.
A severe reaction evokes a significant mononuclear and
neutrophilic infiltrate and thinned or absent epithelium.
71
72. 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.
72
77. 1.Define the use of the material
Material play crucial role.
composition of material.
2. Define how the material has been tested
Usage test –fidelity of reproducing the clinical use
Animal or invitro test-structure of test and method are
employed.
3.Risks and benfits
No material is 100% safe/risk free.
depends on clinical judgement,common sense and data available.
Use require risk benefit analysis.
77
79. Contraction on polymerization, wear, or thermal cycling.
Amalgam, composite, zincphosphate cement, and silicate
cement
TEST MATERIAL PLACED
ZOE
79
80. 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.
80
82. 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.
82
84. Bonding to dentin is more difficult - its composition (being
both organic and inorganic), wetness, and lower mineral
content.
Successful bonding of agents creates 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.
The acids used to remove the smear layer are a potential source
of irritation themselves (phosphoric, hydrochloric,citric, and
lactic acids).
84
85. . Dentin is a very efficient buffer of protons, and most of
the acid may never reach the pulp if sufficient dentin
remains.
A dentin thickness of 0.5 mm has proven adequate.
Citric or lactic acids are less well buffered.
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.
Bonding agents permeate up to 0.5 mm of dentin to cause
significant suppression of cellular metabolism
85
86. 86
Hydroxyethyl methacrylate (HEMA), a
hydrophilic resin contained in several
bonding systems, is at least 100 times
less cytotoxic in tissue culture than
Bis-GMA.
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.
88. Freshly set chemically cured and light-cured resins often cause
moderate cytotoxic reactions in cultured cells.
The cytotoxicity reduced -24 to 48 hours after setting and by
the presence of a dentin barrier.
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.
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.
88
89. Some of the newer composites with non-BisGMA non-
UDMA matrices have significantly lower cytotoxicity.
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
89
90. •90
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.
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
91. Amalgam restorations into the gingival crevice
inflammation of the gingiva as 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.
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. 91
92. 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.
92
93. The cavities, with depths of about 2 mm, were placed
halfway between the cementoenamel junction and the root
tip.
93
94. Amalgam tattoo is an iatrogenic lesion caused by
traumatic implantation of dental amalgam into soft tissue.
Common localised pigmented lesion of oral cavity.
Clinically, amalgam tattoo presents as a dark gray or blue,
flat macule located adjacent to a restored tooth.
Most are located on the gingiva and alveolar mucosa
followed by the buccal mucosa and the floor of the
mouth.
The biologic response to the amalgam is related to particle
size, quantity and elemental composition of the amalgam.
Cosmetic surgery is done for amalgam tattoo.
If cosmetic surgery is not possible then surgical excision
and tranplantation of oral mucosal tissue is done. 94
96. Glass ionomers cement -luting agent and as a restorative
material.
Freshly prepared ionomer is mildly cytotoxic, but effect
reduces with times after setting.
The fluoride release causes cytotoxicity in in vitro tests
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. 96
97. 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
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. 97
98. 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.
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
98
99. Not used under resin-based materials, because resin
components dissolve the thin film of varnish.
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.
Reduce penetration of bacteria or chemical substances
for a time.
Thinness of the film and formation of pinpoint holes, the
integrity of these materials is not as reliable
99
101. Thermal conductivity = Enamel.
Zinc-phosphate cement elicits strong-to-moderate
cytotoxic reactions that decrease with increased time after
setting.
Focal necrosis, observed in implantation tests.
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
101
102. Initially painful and damaging effects on the pulp before
cement is placed in deep cavity preparations, protective
layer of a dentin bonding agent, ZOE, varnish, or calcium
hydroxide is recommended under the cement.
Calcium hydroxide in the powder, lowers 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
102
103. 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
103
104. 104
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).
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.
105. 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.
105
106. Cell culture tests : have shown that some of these
materials are extremely cytotoxic.
In animal tests : caused significant epithelial changes.
In usage : Mild cytotoxity
106
107. Severe cytotoxic reactions.
The adhesives also allowed significant microbial growth
107
108. Wednesday, October 07, 2015 by Malisano Dental
108
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.
109. 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.
109
110. 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
110
112. No local or systemic cytotoxic effect.
Bone response of ziroconia in vivo and inflammed.
112
113. Ceramic material ar known for their high levels of
biocompatibility .
Metal oxides-Al2O3,BaO,CaO,K2O,Li2O,Na2O,ZnOand
Zro2-dental core ceramics or dental veenering ceramics
andSiO2 are principle matrix phase component of all
veenering ceramics.
In highly acidic environment increase of rate of release of
certain metals and silicon ions.
113
114. Invitro Test Proven - Biocompatible.
Nontoxic
Non Injurious
Not Physiologically Reactive.
Light Weighted
High Strength
Excellent Durability To Chemical Agents.
Susceptible To Attack Acidic Fluoride Products.
114
116. Beryllium
Although the beryllium concentration in dental alloys rarely
exceeds 2 wt % the amount of beryllium vapor released in to the
breathing space during melting of Ni-Cr-Be alloys may be
significant over an extended period.
117. · The risk of beryllium vapor exposure is greatest for dental
technicians during alloy melting especially in the absence of an
adequate exhaust and filtration system.
· High levels of beryllium have been measured during finishing
and polishing when a local exhaust system was not used. They
were reduced to levels considered safe when exhaust fan was
used.
· Exposure of beryllium may result in acute and chronic forms of
beryllium disease – BERYLLIOSIS
118. Clinical features
Symptoms range from coughing, chest pain and
general weakness to pulmonary dysfunction.
- Contact dermatitis
- Chemical pneumonitis
119. NICKEL
•It is a great concern to dental patients with a known allergy to
this element.
•Dermatitis resulting from contact with nickel solutions was
described as early as 1989.
•Inhalation, ingestion and dermal contact of nickel or nickel
containing alloys are common because nickel is found in
environmental sources such as air, soil and food as well as in
synthetic objects such as coins, kitchen utensils, and jewellery.
121. Nickel allergy was determined by PATCH TEST LUIS-
BLANCO-DALMAN 1982, [JPD.1982: 48; 99-101] described a
standard patch test consisting of 5% Nickel sulfate solution or 5%
Nickel sulfate solution on a petrolatum base, in centre portion of a
square band-aid of good quality. This is applied on medial aspect
of upper arm, which was cleaned with a alcohol swab. This is left
in place for 48hr undisturbed. A band-aid with out any reagent is
placed adjacent to the first acts a control. After 48 hrs, band-aid is
removed and area is cleaned.
It is read after 20 min.
0 no reaction.
+ erythema is seen.
++ erythema, papules are seen.
+++ erythema, papules, vesicles are seen.
++++ edema with vesicles is seen.
123. No associated chemical or allergic reaction.
Thermal injury can occur for improper handling of
reversible hydrocolloids
Silicosis and pulmonary hypersensivity
Dustless alginate is used.
123
124. Reaction between zinc oxide and eugenol
Used for:
Surgical dressing
Bite registration
Root canal filling materials
Cementing medium
Impression of edentulous mouth
Temporary relining material for denture.
124
125. ZOE paste causes burning sensation and stinging.
Leaching of eugenol .
Zinc oxide can rect with varoius carboxylic acids.
Orthoethoxybenzoic acid is used in regards of eugenols.
125
126. 126
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.
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.
127. 127
Cause allergic problem.
Decreases by thorough
mixing of the material to
avoid contact of aromatic
sulponic ester catalyst with
mucous membrane.
128. Contain some form of peroxide (generally carbamide
peroxide) in a gel form.
Applied to the teeth either by the dentist or by the patient.
Is in contact with teeth for several minutes to several
hours depending on the formulation.
Home bleaching agents is for weeks to even months.
In vitro study-peroxides can rapidly (within minutes)
traverse the dentin in sufficient concentrations to be
cytotoxic.
Cytotoxicity depends to a large extent on the
concentration of the peroxide.
128
129. Peroxides rapidly penetrate intact enamel and reach the
pulp in a few minutes.
Tooth sensitivity is very common.
129
130. Toxicity is the peak circulation levels of local anesthetics.
concentration of local anesthetic administered to patients
are varied according to:
Age
Weight
Health.
Maximum dose -70mg to 500mg
The amount of dose - solution and vasoconstrictor.
130
131. Tissue toxicity - Rare
Can occur if administered
in high enough
concentrations (greater
than those used clinically)
Usually related to
preservatives added to
solution
Systemic toxicity - Rare
Related to blood level of
drug secondary to
absorption from site of
injection.
Range from
lightheadedness, tinnitus
to seizures and
CNS/cardiovascular
collapse
131
132. True allergy is very rare
Most reactions are from ester class - ester hydrolysis
(normal metabolism) leads to formation of PABA - like
compounds
Patient reports of “allergy” are frequently due to previous
intravascular injections
132
133. 133
Inhalation and aspiration of various dust and
toxic vapours-heating and melting of certain
alloys causes respiratory and GIT system
irritation.
Pneumoconiosis is severe fibrotic lung
disease caused by chronic exposure to
inorganic dust.
Exposure to Co-Cr,Co-Cr-Mo and Ni-Cr-Be
alloys cause pneumoconiosis in techinicians.
Benign pneumoconiosis –hard metals.
Malignant pneumoconiosis-dust from
crystalline silics,abestos or beryllium.
134. It was only in 1980 dentists started using gloves.
In March 29, 1991, the FDA issued a bulletin in response
to latex related allergy.
134
135. Processing of latex :
Natural rubber products
While milky sap from tropical trees
.
Ammonia is added to pressure.
hydrolyzes and degrades the sap proteins to
produce allergens.
136. Aerosol –particles are both liquid and solid .
Particle is less than 100 microns.
When water evaporates droplet nuclei is formed of 0.5 to
10 microns.
It can reach to pulmonary alveoli or float in air for several
hours.
Splatter –air borne particles which are larger than 50
microns in diameter.
Mixture of air,water and/or solid substance which is
50micron to several millimeter.
136
137. Aerosol and splatter production which occur with usage
of ultrasonic scalertips and burs at high speed handpiece is
considered to be very exhastive or intensive.
Source- Patient
Dental Unit Waterline
Instruments
137
139. Thermal osteonecrosis and bone drilling parameters
revisited: Augustin, G.etal(2007)
During the drilling of the bone, the temperature could
increase above 47degreeC and cause irreversible
osteonecrosis. The result is weakened contact of implants
with bone and possible loss of rigid fixation.
The aim of this study was to find an optimal conditions
where the increase in bone temperature during bone
drilling process would be minimal.
. Archives of Orthopaedic and Trauma Surgery, [Epub ahead of print].
139
140. Materials and methods-
Influence of different drill parameters was
evaluated on the increase of bone temperature.
1. Diameters-2.5, 3.2 and 4.5 mm
2. Drill speed-188, 462, 1140 and 1820 rpm
3. Feed-rate 24, 56, 84, 196 mm/min
4. Drill point angle 80, 100 and 120degree
5. External irrigation with water of 26 deg C.
140
. Archives of Orthopaedic and Trauma Surgery, [Epub ahead of print].
141. Results-
Combinations of drill speed and diameter with the use
of external irrigation produced temperatures far below
critical.
Without external irrigation, temperature values for the
same combination of parameters ranged 31.4-55.5degC.
Temperatures above critical were recorded using 4.5 mm
drill with higher drill speeds (1140 and 1820 rpm).
141
. Archives of Orthopaedic and Trauma Surgery, [Epub ahead of print].
142. There was no statistical significance of different drill point
angles on the increase or decrease of bone temperature.
The higher the feed-rate the lower the increase of bone
temperature
142
. Archives of Orthopaedic and Trauma Surgery, [Epub ahead of print].
143. Biocompatible Denture Polymers – A Review
Rahul Bhola etal (2009)
This article reviews various denture polymers for their
properties and provides suggestions on the development of
newer polymers for future clinical use.
PMMA resin continues to be the universal versatile polymer in
denture dentistry. Depending upon the type of polymerization,
PMMA resins may leach 0.1-5% of the residual monomer and
additives, mainly MMA and formaldehyde, contributing to
localized allergic reactions
143Trends Biomater. Artif. Organs, Vol 23(3),129-3l6 (2010)
144. Possible carcinogenic and embryotoxic potency of MMA.
Allergic reactions has been observed to increase with the
increased use of higher amounts of PMMA resins.
Development of newer high strength,radio-opaque acrylic
denture materials employing polymer blends, heavy metals and
block co-polymers.
Development of non-leachable plasticizer or plasticizer free
soft denture liners that could retain their softness permanently.
144
Trends Biomater. Artif. Organs, Vol 23(3),129-3l6 (2010)
145. The biocompatibility of a dental material depends on its
composition, location and interactions with oral cavity. Diverse
biological responses to these materials depend on whether they
release their components and whether those components are
toxic, immunogenic, or mutagenic at released concentrations.
Today, in development of any biomaterial one must consider
not only strength, esthetics, or functional aspects of the
material, but its biocompatibility as well. Furthermore,
demands for appropriate biological responses are increasing as
we ask materials to perform more sophisticated functions in
body. Thus considerations of biocompatibility are important to
manufactures, practitioners, scientists and patients
145
way.That is,the material maybe affected in some way by the biological environment,and equally the biological environment maybe affected by the material.
Involves activation of the host immune system to overcome external invasions.
Pulpal and periodontal disease are mainly due to longterm infections.
Histologically - edema of the tissue with infiltration of acute and chronic inflammatory cells.
Involves activation of the host immune system to overcome external invasions.
Pulpal and periodontal disease are mainly due to longterm infections.
Histologically - edema of the tissue with infiltration of acute and chronic inflammatory cells.
passage of nerve impulses through dentin. At the top, impulses are shown stimulating nerves in dentin; this is termed the direct Theory stimulation theory. In the center, an odontoblast is depicted as receptor passing impulses to nerves in the peripheral pulp
in dentin
and hence on to the brain, which is the transduction theory. At the bottom, the diagram displays concept of fluid and odontoblast movement. This movement causes ___ 2 pressure on the nerve endings, which stimas receptor ulates them. The odontoblast thus acts as a mechanoreceptor to nerve endings, which, in turn, conduct impulses to the brain. This is termed the hydrodynamic theory.
Tubules from C.S area range from 20,000/mm² near DEJ to 50,000/mm² near the pulp.
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)
Summary oftheories on the passage of nerve impulses through dentin. At the top, impulses are shown stimulating nerves in dentin; this is termed the direct Theory stimulation theory. In the center, an odontoblast is depicted as receptor passing impulses to nerves in the peripheral pulp
in dentin
and hence on to the brain, which is the transduction theory. At the bottom, the diagram displays concept of fluid and odontoblast movement. This movement causes ___ 2 pressure on the nerve endings, which stimas receptor ulates them. The odontoblast thus acts as a mechanoreceptor to nerve endings, which, in turn, conduct impulses to the brain. This is termed the hydrodynamic theory. (Modified from Bhaskar SN, edi
Hydrodynamics ---3 tor: Orban 's oral histoloW and embryolow, ed
PDL fibers extend from cementum above alveolar crest to alveolar cortical bone or cementum of adjacent teeth.
Due to the minimal release of compounds from most materials, systemic toxicity effects caused by dental materials have been considered to occur very seldomly or not at all. Screening tests for systemic toxicity are therefore justified only with certain body contact for long periods of time with a dental product. The international standardization on biological evaluation of medical devices has demonstrated a need for improved screening tests and continuous revision of the standards for testing. It is obvious that certain published studies on systemic effects of dental materials and some proposed test methods do not reflect today's demand for toxicokinetic and organ effect studies.
PMID: 7844269
a. along the side of the implant
Biocom
A. Cross-section of Class I composite restoration. B. Diagram illustrating the concepts of microleakage (right) and nanoleakage (letf) when bonding dental resins (R) to dentin (D). The dentin has been acid-etched in preparation for the application of the resin, which leaves the collagenous matrix of the dentin exposed (unshaded crosshatched area in upper right side). If the resin does not completely penetrate the collagen network (left) then a samll sapce of communication exists between the dentinal tubules (DT) and the external part of the tooth (arrow, left). This situation is called nanoleakage. On the other hand, if the resin fails to penetrate the collagen network at all, or debonds from it, then the space is much larger (arrow, right). This situation is called microleakage. In the ideal situation (center), the resin penetrates the collagen network all the way to the mineralized dentin. Nanoleakage and microleakage are both important factors in the biocompatibility of dental resin materials.
1 by inhalation of fine particle of alginate.
2is preferred to minimise the risk.
Some common toxic effects:
light headedness
shivering or twitching seizures
hypotension numbness
