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www.indiandentalacademy.com
Biological
properties of
Dental
materials.
INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalaca...
Contents
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Introduction
Biocompatibility v/s Biological properties
Components of biocompatibility
Adverse effects o...
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Advantages & disadvantages of biocompatibility tests
Correlation among the tests
How tests are used together ...
Introduction

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Biological properties of Dental
materials
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Biocompatibility = Lack of interaction
Biocompatible material = list...
Components
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Initial Physiochemical interaction
Effect of the tissue environment
Local host response
Transport...
Adverse effects from Dental
materials

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Toxicity
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Placement of a foreign material in the body carries the possibility
of toxicity
Toxicity can be of 2 types
...
Inflammation
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May result from toxicity or allergy and often it
precedes toxicity.
Oedema, inflammatory cell infiltr...
Allergy

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Allergy
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Body specifically recognizes material as foreign &
reacts disproportional to the amount of material
Gell & C...
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Type 1, 2, 3 – quickly. Eosinophils, Mast cells & B
lymphocytes
Type 4 – delayed. Monocytes & T cells
Allergic ...
Mutagenic reactions
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Alteration in base pair sequence (mutation)
2 types
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Alteration in cellular process tha...
Carcinogenic response
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Currently no dental material has been shown to be
carcinogenic for dental applications in pati...
Local & Systemic effects of
materials
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Local effects
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Pulp
Periodontium
Root apex
Oral tissues – buccal mucos...
Key principles that determine
adverse effects from materials
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A) various types of metal corrosion & other types of
mater...
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B) Surface characteristics :
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Surface is quite different from interior
Examples
 Dental casting alloy containin...
Concept of
Immunotoxicity

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Concept of Immunotoxicity
“ Based on the principle that small alteration in
the cells of immune systems by materials can
h...
Oral anatomy that influences
the Biological response
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Enamel : “seals” the
tooth
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Peroxides permeate
intact enamel
...
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Bone : Osseointegration & Biointegration
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Osseointegration
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Implant & bone closely approximate to each oth...
Measuring the Biocompatibility
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Is not simple and methods of measurement are
evolving rapidly as more is know about t...
In Vitro test
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Placement of a material
or component of it in
contact with cell,
enzyme or some other
isolated biological...
Types of cells used in In-vitro
assays
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Primary cells :
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Directly from an animal into culture
Grows for only a li...
Testing procedures & extent of
testing
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Manufacturer’s responsibility to test new material
A) Initial tests :deals wit...
Cytotoxicity tests
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Measures cell count or growth after exposure to a
material
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Method 1 :
 Place the cells in the...
Tests
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Sensitization test
Oral mucous membrane irritation test
Subcutaneous implant test
Bone implant test

www.in...
Usage tests
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Pulp &Dentine test
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Pulp capping & Pulpotomy test
Endodontic usage test
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Response of dentin...
Correlation among the tests
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Lack of correlation
Less prominent biological response
Barriers may exist
Measure dif...
Advantages & disadvantages
of Biocompatibility tests
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In-Vitro test
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Advantages
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Quick to perform
Least e...
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In- Vivo test
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Advantages
 Allows complex systemic interactions
 More comprehensive
 More relevant
Disadvantage...
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Usage test
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Advantages
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Relevance to use of material is assured

Disadvantages
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Very expensive
Time consum...
How the tests are used together
to measure the Biocompatibility

usage
secondary

primary

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progression
of

testing
...
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Non linear thinking
U
S
P

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Progression
of
Testing

All the 3 tests are done
As test progresses Usage test predomin...


Most common progression

Usage
Primary

Secondary

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‘Recognizes
complexity’
Standards that regulate the
measurement of Biocompatibility
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ANSI / ADA : earliest attempt in 1933
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1972 – The Co...
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ISO Standard 10993 :

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Not restricted to dental materials only
First published in 1992
In 2002 ISO 10993 consist...
Current Biocompatibility
issues in dentistry

www.indiandentalacademy.com



Reactions of pulp to
different materials
Micro leakage :
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If a material does not
bond or debonds at
enamel or ...
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Dentine bonding :
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Bonding to dentine is
difficult – composition,
wetness, low minerals
Smear layer formation &...
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Dentine bonding agents :
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HEMA is 100 times less cytotoxic in tissue culture
than Bis – GMA
Bis – GMA, TEGDMA, UDM...
Amalgam

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Dental amalgam :
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Toxic or not ?
In usage test response of
pulp to amalgam in shallow
or deep lined cavities
Gal...
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Dental cements

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Resin based materials :
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Resin composites –
luting or restorative
Light cured < cytotoxic...
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Glass ionomers :
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Luting agent &
restorative material
Weaker polyacrylic acid
Fluoride release
Histological st...
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Zinc phosphate :
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Luting agent & base
Thermal conductivity closer
to enamel
Pulpal damage in first 3
days du...
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Calcium hydroxide :
Suspension form

Resin containing

Highly cytotoxic

Mild to moderate cytotoxic

Necrosis 1mm or >
...
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Zinc oxide eugenol :
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Suppresses the nerve transmission
Inhibit synthesis of Prostaglandins & Leukotriens

Hamme...
Soft tissue response to the
luting cements
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Apply petroleum jelly

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Clean the excess

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Any residues of cement

www.i...
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Bleaching agents :
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Usually contain some form of peroxide
In-Vitro – traverses the dentine & in sufficient
co...
Latex
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Latex :
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6% to 7% of surgical personnel may be allergic
42% adverse reactions to occupational materials
Hypersens...
Liquid
latex

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vulcanization
sulphur + heat

solid
rubber

Soaked in hot water leaches out allergens
Allergenicity dep...
Impression materials

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Impression materials :
Price & Whitehead
(1972) – Allergic
contact stomatitis &
Foreign body response
Sydiskis ...
Casting alloys
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
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Dental casting alloys :
John c. Wataha 2000
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Release of elements is essential for adverse effects
Identifying ...
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b) Systemic toxicity
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Released metals may not be inside the body
Route of access – I.V < Peritoneal < Oral
Dis...
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d) Allergy to dental casting alloys
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Elemental release is essential for allergy
Metal ions – Haptens
Allergy & To...
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Patch test for metals – controversial
Application of metal ion to skin in the form of patch
 Injecting small amount of...
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Nickel :
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Common component
Incidence of allergy 10% – 20%
Cross reactivity between nickel & palladium (33%
...
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Beryllium :
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Used in Ni-Cr alloys in conc. of 1 – 2 wt%
Forms thin adherent oxides
Documented carcinogen
Beryll...
Reaction of other oral soft tissues
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a) Denture base
materials
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Methacrylates
Greatest potential for
hyper sen...
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True allergy of oral mucosa to denture base
material is very rare

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Residual monomer (methyl methacrylate)

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Allerg...
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b) Soft denture liners &
adhesives
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Release of plasticizers
Extremely cytotoxic
Effects are masked by
the infl...
Denture cleansers
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Used to cleanse the prosthesis
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Eg : Hypochlorite, mild acids, etc.

Biocompatible & cause no ha...
Artificial teeth

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Acrylic & Porcelain teeth

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Acrylic teeth is preferred in poor ridges

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Implants
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Reaction of bone & soft
tissues to implant material
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Materials – Ceramics, Metals, Carbons & Polymers
a) Reaction to c...
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d) Reaction to pure metals & alloys
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‘Metal’ oldest type of oral implant material
Shares the quality o...
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Soft tissue :
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Epithelium forms bond
with implant similar to
that of tooth
C.T apparently does not
bond to the tit...
Conclusion

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List of references
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Restorative dental materials by Craig & Powers
Phillips’ Science of dental m...
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Precautions to be taken in the
Lab






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Make certain the ventilation system in room
is properly functioning
During ...
Thank you
For more details please visit
www.indiandentalacademy.com

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Biological properties of dental materials /certified fixed orthodontic courses by Indian dental academy

  1. 1. www.indiandentalacademy.com
  2. 2. Biological properties of Dental materials. INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
  3. 3. Contents     Introduction Biocompatibility v/s Biological properties Components of biocompatibility Adverse effects of dental materials          Local & Systemic effects of materials Key principles that determine adverse effects from materials Concept of Immunotoxicity Oral anatomy that influences the biological response     Toxicity Inflammation Allergy Mutagenicity Carcinogenicity Enamel Dentine & Pulp Bone Measuring the biocompatibility     Invitro tests Animal tests Usage tests Clinical trials www.indiandentalacademy.com
  4. 4.       Advantages & disadvantages of biocompatibility tests Correlation among the tests How tests are used together ? Regulatory standards for measurement of biocompatibility Current biocompatibility issues in dentistry Reaction of pulp to different materials         Latex Impression materials Biocompatibility of metals Reaction of other oral soft tissues to restorative materials      Dentine bonding & Dentine bonding agents Dental amalgam Dental cements Bleaching agents Denture base material Soft denture liner & adhesives Reactions of bone & soft tissues to Implant materials Conclusion List of references www.indiandentalacademy.com
  5. 5. Introduction www.indiandentalacademy.com
  6. 6. Biological properties of Dental materials      Biocompatibility = Lack of interaction Biocompatible material = list of negatives  Non degradable  Non irritant  Non toxic  Non allergic  Non carcinogenic  Non mutagenic Total inactivity = Passive ignorance ? More appropriate – active acceptance Biocompatibility : ability of a material to perform with an appropriate host response, in a specific application. www.indiandentalacademy.com
  7. 7. Components       Initial Physiochemical interaction Effect of the tissue environment Local host response Transport of products – Systemic effects  Establishment of solid-liquid interface as any material is implanted into the tissue  Protein absorption is the first event Immediate response to injury is inflammation Very few is know about the factors  Condition of the host  Properties of the material  Context in which the material is used Eg: Biocompatible as Crown & Bridge but not as an implant material www.indiandentalacademy.com
  8. 8. Adverse effects from Dental materials www.indiandentalacademy.com
  9. 9. Toxicity   Placement of a foreign material in the body carries the possibility of toxicity Toxicity can be of 2 types  Acute toxicity.  Chronic toxicity.      Type 1: requires prolonged or repeated administration Type 2: requires very few or one dose but long lasting effects Type 1 chronic toxicity is a possibility with “Biomaterials” Eg: metal ions released by gradual corrosion of an implant According to J.J.Jacobs et al (1991)  Vanadium – lungs  Aluminium – surrounding tissues Fortunately, materials causing over toxicity are no longer used in dentistry. www.indiandentalacademy.com
  10. 10. Inflammation    May result from toxicity or allergy and often it precedes toxicity. Oedema, inflammatory cell infiltrate Current biocompatibility research www.indiandentalacademy.com
  11. 11. Allergy www.indiandentalacademy.com
  12. 12. Allergy   Body specifically recognizes material as foreign & reacts disproportional to the amount of material Gell & Coomb’s classification of immune responses       Type 1: Atopic or anaphylactic reaction Type 2: Cytotoxic hypersensitivity reaction Type 3: Immune complex disease Type 4: Delayed or cell mediated hypersensitivity Type 5: Stimulating antibody reaction Type 6: antibody dependent, cell mediated Cytotoxic reaction www.indiandentalacademy.com
  13. 13.      Type 1, 2, 3 – quickly. Eosinophils, Mast cells & B lymphocytes Type 4 – delayed. Monocytes & T cells Allergic response – individual’s immune system recognizes a substance as foreign Allergic reactions – initially dose independent, disproportionate Toxic / inflammatory reactions – dose dependant, proportionate www.indiandentalacademy.com
  14. 14. Mutagenic reactions   Alteration in base pair sequence (mutation) 2 types     Alteration in cellular process that maintain DNA integrity Direct interaction Can occur from radiations, chemicals, errors in DNA replication process Examples    Metal ions – nickel, copper, beryllium Few components of root canal sealers Resin based materials to some extent www.indiandentalacademy.com
  15. 15. Carcinogenic response   Currently no dental material has been shown to be carcinogenic for dental applications in patients However, carcinogenesis is often exceedingly difficult to prove or disprove conclusively www.indiandentalacademy.com
  16. 16. Local & Systemic effects of materials  Local effects      Pulp Periodontium Root apex Oral tissues – buccal mucosa, tongue Systemic effects  Function of the distribution of substances released from the materials     Access to the body by      Simple diffusion Lymphatics Blood vessels Ingestion & absorption in gut Inhalation Release at tooth apex Absorption into mucosa Systemic response depends on    Duration & concentration of the exposure Excretion rate of the substance Site of the exposure www.indiandentalacademy.com
  17. 17. Key principles that determine adverse effects from materials  A) various types of metal corrosion & other types of material degradation :   Biocompatibility depends on the degradation process Corrosion is determined not only by material composition but also by the biological environment Many ways for release of products in host    Metal prosthesis – releases metal ions by  Electrochemical force  Particles dislodged by mechanical forces Resin composites  Cyclic stresses  Salivary esterases www.indiandentalacademy.com
  18. 18.  B) Surface characteristics :    Surface is quite different from interior Examples  Dental casting alloy containing 70% gold may have 95% gold at its surface  Relative unpolymerized state of a sealant at its surface The surface composition, roughness, mechanical & chemical properties are critical to the biocompatibility www.indiandentalacademy.com
  19. 19. Concept of Immunotoxicity www.indiandentalacademy.com
  20. 20. Concept of Immunotoxicity “ Based on the principle that small alteration in the cells of immune systems by materials can have significant biological consequences ”  Examples:   Mercury ions increase the Glutathione but Palladium decreases Glutathione content of Monocytes HEMA may change the ability of Monocytes to direct an immune response once challenged by plaque or others agents www.indiandentalacademy.com
  21. 21. Oral anatomy that influences the Biological response  Enamel : “seals” the tooth   Peroxides permeate intact enamel Dentine & Pulp :    Smear layer Effective in reducing the hydrostatic pressure but not diffusion Acid etching www.indiandentalacademy.com
  22. 22.  Bone : Osseointegration & Biointegration  Osseointegration      Implant & bone closely approximate to each other Approximation less than 100 A No fibrous tissue in intervening space Titanium alloys Biointegration Implant & bone are fused to one another & are continuous  Occurs with Ceramic & Ceramic coated metal implants Eg: Calcium & Tri calcium phosphate, Hydroxyapatite, Bioglass  www.indiandentalacademy.com
  23. 23. Measuring the Biocompatibility   Is not simple and methods of measurement are evolving rapidly as more is know about the interactions between dental materials and oral tissues & as technologies for testing improves Classified as     In Vitro test Animal test Usage test Clinical trial – special case of a usage test in humans www.indiandentalacademy.com
  24. 24. In Vitro test  Placement of a material or component of it in contact with cell, enzyme or some other isolated biological system   Direct  Material in contact  Physically present or extract from material Indirect  Some sort of barrier www.indiandentalacademy.com
  25. 25. Types of cells used in In-vitro assays  Primary cells :    Directly from an animal into culture Grows for only a limited time Continuous cells :  Primary cells transformed to allow them to grow indefinitely www.indiandentalacademy.com
  26. 26. Testing procedures & extent of testing   Manufacturer’s responsibility to test new material A) Initial tests :deals with general biocompatibility & systemic effects of a material  Short term systemic toxicity test    Acute systemic toxicity test   Dental remedies that have significant volatility under usage condition Hemolysis test   I.V administration Inhalation toxicity test   Short time oral administration Toxicity profile In vitro evaluation of hemolytic activity of materials intended for prolonged tissue contact Emes mutagenicity & the dominant lethal test  To asses the potentialwww.indiandentalacademy.com carcinogenic activity
  27. 27. Cytotoxicity tests  Measures cell count or growth after exposure to a material   Method 1 :  Place the cells in the well of a cell culture dish  If Cytotoxic - cell may stop growing, exhibit cytopathic features or detach from the cell Method 2 :  Measurement of cytotoxicity by a change in membrane permeability  Loss in membrane permeability is equivalent or very nearly equivalent to cell death  Identifies the cells that are alive or dead www.indiandentalacademy.com
  28. 28. Tests     Sensitization test Oral mucous membrane irritation test Subcutaneous implant test Bone implant test www.indiandentalacademy.com
  29. 29. Usage tests  Pulp &Dentine test     Pulp capping & Pulpotomy test Endodontic usage test    Response of dentine & pulp Minimum experimental variables Assess response of the pulp wound & the periapical tissue Influenced by – level at which the pulp tissue is cut off & total removal of pulp tissue Bone implant usage test  To evaluate all materials that, during their intended use, penetrate the oral mucosa and the adjacent bone www.indiandentalacademy.com
  30. 30. Correlation among the tests     Lack of correlation Less prominent biological response Barriers may exist Measure different aspects of the biological response to the material www.indiandentalacademy.com
  31. 31. Advantages & disadvantages of Biocompatibility tests  In-Vitro test  Advantages       Quick to perform Least expensive Standardized Large scale screening Excellent for mechanisms of interaction Disadvantages  Relevance to In-Vivo questionable www.indiandentalacademy.com
  32. 32.  In- Vivo test   Advantages  Allows complex systemic interactions  More comprehensive  More relevant Disadvantages  Relevance to use ?  Expensive  Time consuming  Ethical concern  Difficult to control  Difficult to interpret & quantify www.indiandentalacademy.com
  33. 33.  Usage test  Advantages   Relevance to use of material is assured Disadvantages    Very expensive Time consuming Major legal / ethical www.indiandentalacademy.com
  34. 34. How the tests are used together to measure the Biocompatibility usage secondary primary    progression of testing Linear paradigm, relies on the accuracy of the primary tests (challenged by Major et al 1977) No prediction of results in usage tests www.indiandentalacademy.com Lack of correlation in In-Vitro tests
  35. 35.  Non linear thinking U S P   Progression of Testing All the 3 tests are done As test progresses Usage test predominates www.indiandentalacademy.com
  36. 36.  Most common progression Usage Primary Secondary www.indiandentalacademy.com ‘Recognizes complexity’
  37. 37. Standards that regulate the measurement of Biocompatibility  ANSI / ADA : earliest attempt in 1933    1972 – The Council on dental material, instruments & equipment of ANSI / ADA approved document no. 41 for recommended standard practices for biological evaluation of dental materials In 1982 updated to include test for mutagenicity Uses linear paradigm www.indiandentalacademy.com
  38. 38.  ISO Standard 10993 :     Not restricted to dental materials only First published in 1992 In 2002 ISO 10993 consisted of 16 parts 2 types of tests –    Initial – Cytotoxicity, sensitization & systemic toxicity. In – Vitro / animal test Supplementary – chronic toxicity, carcinogenicity & bio-degradation. Animals / Humans Specialized tests – Eg: dentine barrier test www.indiandentalacademy.com
  39. 39. Current Biocompatibility issues in dentistry www.indiandentalacademy.com
  40. 40.   Reactions of pulp to different materials Micro leakage :    If a material does not bond or debonds at enamel or dentine Previous belief Concept of nano leakage   Between mineralized dentine & bonded material. In very small spaces of demineralized matrix into which material did not penetrate Hydrolytic degradation of dentine – material bond www.indiandentalacademy.com
  41. 41.  Dentine bonding :    Bonding to dentine is difficult – composition, wetness, low minerals Smear layer formation & removal Many studies have shown  0.5mm of RDT is adequate  Dentine is a buffers of protons  Penetration of acids < 100 micrometers www.indiandentalacademy.com
  42. 42.  Dentine bonding agents :   HEMA is 100 times less cytotoxic in tissue culture than Bis – GMA Bis – GMA, TEGDMA, UDMA www.indiandentalacademy.com
  43. 43. Amalgam www.indiandentalacademy.com
  44. 44.  Dental amalgam :    Toxic or not ? In usage test response of pulp to amalgam in shallow or deep lined cavities Gallium based amalgam     Excessive gallium release, roughness, discolor Significant foreign body reaction Absorption : 1 – 3 micrograms / day Minimum dose to produce observable toxic effect is 3 micrograms / kg body weight www.indiandentalacademy.com
  45. 45.  Dental cements  Resin based materials :     Resin composites – luting or restorative Light cured < cytotoxic than chemically cured Pulpal reaction diminishes after 5 – 8 weeks Protective liner or bonding agent minimizes Pulpal reaction www.indiandentalacademy.com
  46. 46.  Glass ionomers :     Luting agent & restorative material Weaker polyacrylic acid Fluoride release Histological studies in usage test shows that any inflammatory infiltrate to ionomer is minimal or absent after 1 month www.indiandentalacademy.com
  47. 47.  Zinc phosphate :      Luting agent & base Thermal conductivity closer to enamel Pulpal damage in first 3 days due to initial low PH(4.2), reaches neutrality in 48 hours When placed in deep cavities ? Inclusion of Ca- OH to the powder or lowering the concentration of phosphoric acid www.indiandentalacademy.com
  48. 48.  Calcium hydroxide : Suspension form Resin containing Highly cytotoxic Mild to moderate cytotoxic Necrosis 1mm or > No necrotic zone shortly Neutrophil infiltration Dentine bridge formation is quick 5 to 8 weeks Slight inflammatory response wks - months Dystrophic calcification Dentine bridge www.indiandentalacademy.com
  49. 49.  Zinc oxide eugenol :    Suppresses the nerve transmission Inhibit synthesis of Prostaglandins & Leukotriens Hammesfahr 1987, initiated the search for a biocompatible resin base system incorporating Calcium hydroxide “ PRISM VLC DYCAL” www.indiandentalacademy.com
  50. 50. Soft tissue response to the luting cements  Apply petroleum jelly  Clean the excess  Any residues of cement www.indiandentalacademy.com
  51. 51.  Bleaching agents :     Usually contain some form of peroxide In-Vitro – traverses the dentine & in sufficient conc. can be cytotoxic Penetrates intact enamel & reaches the pulp in few min. May burn gingiva www.indiandentalacademy.com
  52. 52. Latex www.indiandentalacademy.com
  53. 53.  Latex :    6% to 7% of surgical personnel may be allergic 42% adverse reactions to occupational materials Hypersensitivity may be due to true latex allergy or reaction to accelerator & antioxidants White, milky sap Addition of ammonia Hydrolyses & degrades the sap proteins to produce allergens www.indiandentalacademy.com
  54. 54. Liquid latex   vulcanization sulphur + heat solid rubber Soaked in hot water leaches out allergens Allergenicity depends on collecting, preservation & processing www.indiandentalacademy.com
  55. 55. Impression materials www.indiandentalacademy.com
  56. 56.     Impression materials : Price & Whitehead (1972) – Allergic contact stomatitis & Foreign body response Sydiskis & Gerhardt (1993) – some degree of toxicity in cell culture Gabriela Mazzanti et al (2005) – no significant evidence of diffuse inflammation or local skin reaction www.indiandentalacademy.com
  57. 57. Casting alloys www.indiandentalacademy.com
  58. 58.   Dental casting alloys : John c. Wataha 2000    Release of elements is essential for adverse effects Identifying & quantifying the elements that are released is most relevant measure from stand point of Biocompatibility a) Release of elements from casting alloys Multiple phases  Inherent tendency to release elements – lability Eg: Cu, Ni, Cd, Zn & Ga – highly labile  Environmental conditions - PH  www.indiandentalacademy.com
  59. 59.  b) Systemic toxicity     Released metals may not be inside the body Route of access – I.V < Peritoneal < Oral Distribution – there is no documented proof that these material cause ‘Systemic toxicity’ c) Local toxicity    Micro environment exists around casting alloys Metal ions can cause local toxicity Increased exposure causes increased toxicity www.indiandentalacademy.com
  60. 60.  d) Allergy to dental casting alloys    Elemental release is essential for allergy Metal ions – Haptens Allergy & Toxic reaction – difficult to distinguish www.indiandentalacademy.com
  61. 61.  Patch test for metals – controversial Application of metal ion to skin in the form of patch  Injecting small amount of ion below the skin  Assessment of the response is difficult  Salt of metal ions important for response Eg: chloride, sulphate, nitrate salts  Vehicle – whether its water, oil or petrolatum can vary the response   Grimaudo N.J 2001 – true allergic hypersensitivity to dental casting alloys is rare www.indiandentalacademy.com
  62. 62.  Nickel :      Common component Incidence of allergy 10% – 20% Cross reactivity between nickel & palladium (33% & 100%) Nickel ions induces ICAM’s in the endothelium – release of cytokines It may contribute to any intraoral inflammation around nickel containing crowns www.indiandentalacademy.com
  63. 63.  Beryllium :     Used in Ni-Cr alloys in conc. of 1 – 2 wt% Forms thin adherent oxides Documented carcinogen Berylliosis   Individual is hypersensitive Inhalation of beryllium dust, salts, fumes www.indiandentalacademy.com
  64. 64. Reaction of other oral soft tissues  a) Denture base materials     Methacrylates Greatest potential for hyper sensitization Acrylic & diacrylic monomers, curing agents, antioxidants, amines, formaldehydes For the patients most of these materials have been reacted in polymerization and thus less prone www.indiandentalacademy.com
  65. 65.  True allergy of oral mucosa to denture base material is very rare  Residual monomer (methyl methacrylate)  Allergic acrylic stomatitis  Heat cured is better www.indiandentalacademy.com
  66. 66.  b) Soft denture liners & adhesives     Release of plasticizers Extremely cytotoxic Effects are masked by the inflammation Denture adhesives show severe cytotoxic reactions In-Vitro  Large amount of formaldehyde  Allowed significant microbial growth www.indiandentalacademy.com
  67. 67. Denture cleansers  Used to cleanse the prosthesis   Eg : Hypochlorite, mild acids, etc. Biocompatible & cause no harm to the patient www.indiandentalacademy.com
  68. 68. Artificial teeth  Acrylic & Porcelain teeth  Acrylic teeth is preferred in poor ridges www.indiandentalacademy.com
  69. 69. Implants www.indiandentalacademy.com
  70. 70. Reaction of bone & soft tissues to implant material   Materials – Ceramics, Metals, Carbons & Polymers a) Reaction to ceramic implant material      b) Hydroxyapatite    Very low toxic effects. Oxidized state, corrosion resistant Used as a porous or dense coating Root surface porosities > 100microns (firmly bound ) Root surface porosities < 100microns (fibrous ingrowth) Relatively non resorbable form of calcium phosphate Coating material & ridge augmentation material c) Beta -Tricalcium phosphate  Another form of calcium phosphate, has been used in situations where resorption of the material is desirable www.indiandentalacademy.com
  71. 71.  d) Reaction to pure metals & alloys        ‘Metal’ oldest type of oral implant material Shares the quality of ‘strength’ Initially selected on the basis of the ‘Ease of fabrication’ Stainless Steel, Chromium-Cobalt-Molybdenum, Titanium and its alloys Most commonly used is Titanium Titanium’s Biocompatibility is associated with its fast oxidizing capacity. Corrosion resistant & allows Osseointegration www.indiandentalacademy.com
  72. 72.  Soft tissue :   Epithelium forms bond with implant similar to that of tooth C.T apparently does not bond to the titanium, but forms a tight seal that seems to limits ingress of bacteria & its products www.indiandentalacademy.com
  73. 73. Conclusion www.indiandentalacademy.com
  74. 74. List of references              Restorative dental materials by Craig & Powers Phillips’ Science of dental materials Chemistry of medical & dental materials by J.W.Nicholson Concise Encyclopedia of medical & dental materials by David Williams Dental biomaterials by Arturo N. Natali Dent material 2005;21(4):371-74 JPD 2001 Aug;86(2):203-9 Gen Dent 2001 Sep-Oct;49(5):498-503 JPD 2000 Feb;83(2):223-34 JPD 1998 Sep;80(2):203-9 JPD 1993;69;431-5 J Biomater Appl 1987 Jan;1(3):373-81 BDJ 1972;133:9-14 www.indiandentalacademy.com
  75. 75. www.indiandentalacademy.com
  76. 76. Precautions to be taken in the Lab     Make certain the ventilation system in room is properly functioning During operation of the dental lathe wear a protective eyewear & a mask Clean & disinfect the dental lathe at least once daily Use sterile rag wheels, stones & fresh pumice for each patient's prosthesis www.indiandentalacademy.com
  77. 77. Thank you For more details please visit www.indiandentalacademy.com www.indiandentalacademy.com

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