This document provides information about dental materials from a group of students at Women's University in Sialkot, Pakistan. It defines dental materials and the science of dental materials. It discusses the ideal characteristics, selection, evaluation, and properties of dental materials. The properties discussed include thermal, optical, corrosion, hardness, adhesion, cohesion, electrical, biological, and mechanical properties. It provides examples and definitions for each type of material property.

2. GC. WOMEN UNIVERSITY, SIALKOT.
MEMBERS = ANAM FATIMA, BUSHRA, TEHREEMA, TABINDA, AMMARA AND
AQSA.
TOPIC:

3. Introduction
 DEFINITION:
“Dental materials are used to replace tooth structure lose,
usually due to dental caries but also tooth wear and dental trauma’’.
 SCIENCE OF DENTAL MATERIALS:
“It defines the study of composition and properties of dental
materials and the manner in which they interact with the
environment they are placed”.

4. The science of dental materials is the basic science which deals
with the physical, mechanical and biological properties of the
dental materials. This study give the knowledge that helps
to choose the material and allow to manipulate effectively.
 WHY WE STUDY DENTAL MATERIALS
 Safety—handling, disposal, patient safety
 Maintenance—cleaning, polishing, instrumentation
 Delivery—behavior of material, manipulation of
material, assisting in the delivery of material
 Patient education—options of material choices, maintenance

5. History of dental materials
from ancient time to 1700s
 Replacement of teeth.
 Ivory- Which was carved
 Porcelain- Filled into teeth shapes.
 Wax and Gypsum-which were used for impressions and models
 Zinc oxide–eugenol and zinc phosphate, which evolved as
fillings and cements to "glue” the restoration to the tooth

6. In 1980s---
 Amalgam-A white filling material, widely used.
 Porcelain-Used for inlays and crowns.
In 20th century—
 Polymers and composite introduce.
 Cast material used for crown bridges and partial dentures.
 Alloys are made of gold, titanium and chromium.
In 21th century–
 Ceramic materials and new technologies are coming day by day.
 Basic concepts and uses are same.

7. Ideal characteristics of Dental
material
 Should be Biocompatible
♣ Non-toxic, Non-irrigating , Non-allergic.
 Mechanical stable and durable
♣ Strong and resist to fracture.
 Resistant to corrosion
♣ Does not deteriorate over time.
 Dimensionally stable
♣ Little change by temperatures and solvents.

8.  Minimal conduction
♣ Insulate against thermal and electrical changes.
 Esthetic
♣ Look like oral tissues.
 Easy to manipulate
♣ Minimal efforts and time needed.
 Adheres to tissues
♣ Retain onto, seals the tooth structure.
 Should be cleanable and repairable.
 Should be tasteless and odorless.
 Should be cost effective.

9. Selection of
Dental materials
 Variety of the materials are available
so they requires proper selection.
 Proper selection leads to success for
Restoration.
 Selection is subjected to the need and
type of restoration.

10. Evaluation of dental materials
Proper evaluation and testing of materials required before
Application.
STEPS FOR EVALUATION:
 Standard specification (Quality level maintenance)
 Clinical trials (for indicating suitability of materials )
 Laboratory evaluation (information and data regarding to material )

11. properties of dental materials

12. THERMAL PROPERTIES
THERMAL CONDUCTIVITY:
It is define as:
“The rate of heat flow per unit temperature gradient”.
It is factor which determines the ease with which the heat is transferred to
the material.
It is represented by “K” and its unit are Cal s-1 cm-2 or W m-1 oC

13. THERMAL DIFFUSIVITY:
It is the measure of transient heat flow and can be defined by the
equation:
α = K/ (CP × ρ)
Where K is the Thermal conductivity, CP is the heat capacity and ρ is the
density.
Its units are mm2/sec.
High value of diffusivity is preferred in denture base materials.
Materials Thermal diffusivity(mm2
/sec)
Acrylic resins 0.123
Enamel 0.469

14. EXOTHERMIC REACTIONS:
 Many dental materials involves mixing of two or more components followed by setting and the
chemical reaction during setting is exothermic in nature.
 This property is needed for dental pulp protection.
 Some typical values of temperature rise recorded for small samples of some dental materials
are:
SPECIFIC HEAT:
 It is the quantity of heat needed to raise the temperature of one gram of substance by 1oC.
 It is represented by CP and its unit is J/g/ oC
 For metallic filling, CP of the materials should be low so it reduces heat conduction.
Materials Temperature rise (oC)
Zinc phosphate cement 1.9
Composite resins 4.0
Materials Specific heat(J/g/oC)
Dental amalgam 0.23
Acrylic resin 1.46

15. OPTICAL PROPERTIES
COLOUR:
Color selection is very important.
It depends on many physical factors.
Important parameters used to define color are:
 Hue:
It is refers to a property associated with the color of object whether it is
green, red or blue.
It is the basic color of an object.
CHROMA:
Measures the intensity of color.
It is a degree of saturation of particular hue.
The low value of chroma indicates the weak color.
.

16. Value:
It is defined as the relative lightness, darkness of a color or brightness of an
object.
• Value of 0= black
• Value of 10 = white
TRANSLUCENCY:
Property of a substance that permits passage of light but disperses the light.
Object cannot be seen through the material in it.
Example: Some translucent materials used in dentistry are porcelain,
composite resins and dental plastics.
TRANSPARENCY:
Property of a substance that allows the passage of light in such a manner
that little distortion takes place.
Object can be clearly seen through the material in it.
Example: Glass

17. CORROSION
Term specifically characterizes the chemical reactivity of metals and alloys.
So, it is a property of metals and alloys and they are good conductors.
Corrosion can be classified into two types:
CHEMICAL CORROSION:
It occur when metals reacts to form compounds such as oxides and sulfides.
It is also known as “Non-aqueous corrosion”.
Example: blackening of a surface of dental amalgam if chemically reacts with
sulfur compound in the air.

18. ELECTROCHEMICAL CORROSION:
It occurs by electrochemical reaction .
It is also known as “Aqueous corrosion”.
Occurs in oral cavity where the electrolyte is saliva.
o Discoloration and corrosion occurs in:
• Amalgam restoration
• Soldered appliances

19. HARDNESS
 Hardness is one of the major property of in the comparison of restorative
material.
 It is defined as “the property of material that enable it to resist deformation,
that occur usually by penetration of another material”.
 It is also known as resistance of a material to bending, scratching or cutting.
 The most common concept of the hard and soft substance is their relative
resistance to indentation.
Examples:
• Ceramics
• Concrete
• Super hard materials

20. ADHESION PROPERTY
 It is the force of attraction between the
molecules/atoms of two different surface as they
are brought into contact.
It is the surface property of dental material, in
which a Dentist applies a tooth-colored resin
material (a durable plastic material) and cures it
with visible, blue light. This ultimately “bonds” the
material to the tooth and improves the overall
appearance of teeth.
If the adhesion property between tooth colored
resin material is effective then appearance of teeth
improve otherwise not.
Examples:
• plaque or calculus attaching to the tooth structure.
• Saliva attaching to denture surface on tissues.

21. COHESION PROPERTY
The force of attraction between molecules/atoms within one materials.
 It is not a surface property.
 It is the property of dental material sticking together or to stick with tooth.
 Cohesive forces are also called interatomic binding force
CLASSIFICATION:
Primary cohesive forces/bonding
Ionic bond
Covalent bond
Secondary cohesive forces/bonding
Vander walls forces
Hydrogen bonding

22. ELECTRICAL PROPERTY
 It is the ability of metal to ionize by
losing electron.
 If there is a high difference in the
electrode potential of material in contact
with the same solution like gold and
aluminum an electric current may
developed and the patient may fell
discomfort.
 Galvanism is one of the most important
phenomenon of electrical property of
dental material.
o Fig. Indicate the measurement of
electrical property of a corrode teeth .

23. GALVANISM
 The presence of metallic restoration in the mouth
may cause a phenomenon called galvanic action or
galvanism.
 Galvanic action mostly caused by aluminum and
gold metal alloy.
 This result from a difference in potential between
dissimilar filling in adjacent teeth. These filling in
conjunction with saliva or bone fluids such as
electrolytes make upon electric cell.
 This cell is short circuited, and if the flow of current
occurs through the pulp, the patient experience
pain and the more anodic restoration may corrode
like gold with amalgam.

24. ORAL GALVANISM
 Oral galvanism is claimed to occur
when two or more dissimilar metals
in dental restorations which are
bathed in saliva, or a single metal in
contact with two electrolytes such as
saliva and pulp fluid tissue, produce
an electric current.
 when associated with pain, the term
galvanic pain is used.
 So, always used properly coated
dental metal covering restoration
material.

25. BIOLOGICAL PROPERTIES
The dental material should be biocompatible.
It should be non toxic.
It should be non irritant.
It should be non carcinogenic non allergic potential.
It should be harmless to the patient when placed into its mouth and does
not cause galvanic action.
It should be harmless to the manufacturer.

26. MECHANICAL
PROPERTIES
 It is one of the major property of
dental materials.
 It is the ability to withstand the
various mechanical force placed
on them during the use as
restoration.
 There are various types of
mechanical forces that act upon
on dental material are as follows,
Mechanical
forces
Stress
Strain
Ductility
Toughness
Brittleness
Malleability

27. STRAIN:
 It is the change in dimension per unit
dimension caused by externally applied
force.
Strain= Elongation / original length
Percentage of elongation = strain × 100%
STRENGTH:
 It is maximal stress require to
fracture a material”.
 Also defined as the average level of
stress at which a material exhibits
a certain amount of plastic
deformation.
 It can be measured as the resistance
of a material to externally applied
forces.
STRESS:
 It is a force per unit area induced
in a body in response to some
external forces.
 For a given, the smaller the area
applied to, the larger the value of
the stress.
 Stress common in mouth because
biting forces are small

28. DUCTILITY:
 It is the ability of the material to
withstand permanent deformation
under tensile stress without
fracture(plastically deformed
material).
 Examples:
o Low carbon steel
o Aluminum
o Bubble gum
MALLEABILITY:
It is the ability of the material to
withstand permanent deformation
under tensile stress without
fracture(plastically deformed
material)”
 Examples:
o Low carbon steel
o Aluminum
o Bubble gum

29. TOUGHNESS
 Toughness is the ability of a material to
withstand both plastic and elastic deformation.
 Toughness is measure as the amount of energy
absorbed by a material before actual fracture or
failure takes place.
 It is the total area under the stress – strain
curve.
 Example: Wrought iron and Mild steel
BRITTLENESS
 If a material showed no or very
little plastic deformation on
application of load it is
described as being brittle.
 In other words a brittle
material is fracture at or near its
proportional limit.
 Examples: Glass and Dental
amalgam

30. CLASSIFICATION OF DENTAL MATERIALS:
TEMPORARY DRESSING
 Cement
 Impression material
 Restorative material
DIRECT RESTORATIVE MATERIAL
Amalgam
 Composite resins
 Glass ionomer cement
INDIRECT RESTORATIVE MATERIAL
 Porcelain
 Gold

31. TEMPORARY DRESSING:
A dental filling which is not intended to last in the long term.
 A paste based on filled polymer composition
 Interim material
Therapuetic properties
USE: root canal therapy
Examples:
o Zinc oxide eugeonl.
o Kelvin

32. CEMENTS:
 Substance that hardens to act as base liner , filling material or prosthesis
to tooth structure
COMPOSITION:
 water based acid base include zinc phosphate and oil based include zinc
oxide .
REACTION:
formed by acid base .
PROPERTIES:
 Biocompactable
 Provide insulation
USES:
 used to adhere enamel and dentin
 used to bond indirect restoration.

33. IMPRESSION MATERIAL:
 Negative imprints of teeth and soft oral
tissue from which a positive
representation can be cast.
COMPOSITION:
plaster of paris, polysulfides, addition silicones,
agar hydrocollide, polyethers, metal oxide
PROPERTIES:
 Economical, insulative, disinfective, dimension stability
USES:
 Implantology
 Prosthodontics
 Board moulding

34. RESTORATIVE MATERIAL:
 It is used to restore the function,integrity and morphology of missing tooth
structure.
TYPES:
DIRECT RESTORATIVE MATERIAL:
They are directly placed into cavity on tooth and shape to fit it
AMALGAM:
Metallic filling material
COMPOSITION: A mixture of mercury(43-54%) and powdered alloys made of
zinc,silver,tin and copper.
USE: It adhere to tooth structure with the help of
Cements which lock the filling.
PROPERTY: Superior strength.

35. COMPOSITE RESINS:
 filling is a tooth-colour plastic and glass mixture used to restore decayed teeth
COMPONENTS: matrix,filler,coupling agent
USE:
It is used to fill a carious lesion involving highly visible areas.

36. GLASS IONOMER CEMENT:
 A cement that consists of basic glass and
acidic polymer which sets up by acid base
reaction between them
GLASS: Acid decomospeable glass
ACIDIC POLYMER : Typically polyarcylic acid
ESSENTIAL ELEMENTS:
 Acid-base setting reaction
 Ionexchange adhesion without tooth
 Continually ion activity
CURE:
 Auto cure
 Dual cure

37. INDIRECT RESTORATIVE MATERIAL:
 Tooth or teeth to receive the restoration are first prepared, then a dental
impression is taken by dentist
Types:
 PORCELAIN:
 It is hard and brittle and always used for molar teeth
 GOLD:
 Excellent durability, wear well, and do not
Cause excessive wear to the opposing teeth

38. DENTAL CROWNS:
DEFINITION:
Dental crown is a tooth shaped cap that is placed over a
tooth to cover a tooth to restore its shape and size, strength and
improve its appearance.
WHY IT IS NEEDED?
 To protect weak tooth .
 To restore an already broken teeth.
 To hold dental bridge in place .
 To cover dental implant.
 To save teeth that has been damaged by decay

39. TYPES OF CROWN:
Classification of crowns is based upon the material that is
used for their production and it includes:
STAINLESS STEEL:
 These are prefabricated crowns that are used on permanent teeth as
temporary measure.
METALS:
 These type of crowns withstand biting and chewing forces and probably last the
longer in terms of wear down .
PORCELAIN FUSED TO METAL:
These crowns can be colour matched to adjacent teeth (unlike metal crown).

40. ALL RESIN:
 They are less expensive and usually only used for temporary crown . They are
prone to fractures.
ALL CERAMIC OR ALL PORCELAIN:
Dental crowns provide natural colour and good for front teeth.
Advantages :
 Support a teeth that has been damaged
 Anchor dental bridge .
 Add length or width to mishaped teeth
disadvantages :
 Infection and shifting of crown
 Allergic reaction and poor bite
 Tooth decay

41. TOOTH BRIDGES:
INTRODUCTION:
Dental bridge is a fixed device that replace one or more missing
teeth.
 Missing teeth can effect ability to chew , alignment of teeth and
shape of face.
 Dental bridges can be made up of metal , porcelain or ceramic
material or a metal base with a porcelain or ceramic coating.
 It is a permanent device that can’t be taken out of mouth.

42. Types of bridges :
All types fill a space by one or by more missing teeth with an artificial tooth .
Types include:
TRADITIONAL BRIDGES:
Consist of artificial tooth attached to two or more crowns . Crowns are mean to
support it.
CANTILEVER BRIDGES:
They replace a missing teeth that has only one teeth on side of it .
MARYLAND BRIDGES:
Typically used for front teeth because they create more natural appearance.

43. Advantages:
Improve dental occlusion.
 prevent shifting of teeth due to missing teeth.
Disadvantages :
 Extra forces placed on supporting teeth.
 Not able to floss bridge must be other aid.
 Lack of stimulation of bone leads to jaw bone defect.
 Risk for decay under bridge.

44. NANOTECHNOLOGY IN DENTISTRY
NANOTECHNOLOGY
Nanotechnology deals with the physical, chemical, and
biological properties of structures and their components at
nanoscale dimensions.
Now a days, nanotechnology playing a very important role
in dental material. This is known as “NANODENTISTRY”.
New nanomaterials for dental treatments boast impressive
antibacterial, decay-resistant and biomimetic properties. In
combination with stem cells, they are even capable of
regenerating dental tissues.

45. INTRODUCTION:
In dentistry, composites consisting of inorganic fillers such as
radiopaque glass, quartz or ceramic particles and an organic resin
matrix based on a mixture of dimethacrylates, are used for the
restoration of teeth.
 Important properties of the dental restorative materials can be
improved by means of nanotechnology. Furthermore, nanofillers can
contribute to increasing the modulus of elasticity or improving the
optical properties of the dental composites and are useful as starting
compounds for the synthesis of new low temperature processable
dental ceramics.
Inorganic-organic hybrid materials can be used as monomer matrix in
dental restoratives to diminish their polymerization shrinkage and
improve their wear resistance and biocompatibility.

46. NANOROBOTS:
Although medical robots are not anticipated to have an effect on
dentistry in the near future, it is not too early to consider their potential
effects.2 Dental nanorobots are able to move through teeth and
surrounding tissues by using specific movement mechanisms.
Nanocomputers that have been previously programmed via acoustic
signals used for ultrasonography can control nanorobotic functions.
Nanorobots (dentifrobots) left by mouth wash or toothpaste on the
occlusal surfaces of teeth can clean organic residues by moving
throughout the supragingival and subgingival surfaces, continuously
preventing the accumulation of calculus. These nanorobots, which can
move as fast as 1 to 10 micron/second, are safely deactivated when
they are swallowed

47. FUNCTIONS OF NANOROBOTS:
Induce local anesthesia
Avoid patients discomfort
Major tooth repair
Dentofrobots
NANOTECHNOLOGY TOOTHPASTE:
 The small nanoparticles of hydroxyapatite prevent the tooth from
decaying it also rebuilds the teeth by placing a coating on the tooth to
protect it from future damage.
If hydroxyapatite is swallowed it does not upset the stomach, and it is
not as toxic as regular toothpaste.

48. NANO COMPOSITES:
The increasing interest in esthetic restorations in recent years has led to
further development of materials that have the same color as that of teeth
Nanoparticles allow the production of composites with a smooth surface
after the polishing process and confer superior esthetic features to the
material. Composite resins containing such particles are easy to shape and
have a high degree of strength and resistance to abrasion
The fillers in Nano-composites have higher translucence since they are
smaller than the wavelength of light, allowing the generation of more
esthetic restorations with a vast range of color options.

49. NANOCOMPOSITE ARTIFICIAL TEETH:
 In artificial teeth, inorganic fillers in Nano-dimensions are diffused
homogenously without any accumulation in the matrix. Therefore, the
smoothness of the surface can be preserved even when the teeth are eroded.
nanocomposite artificial teeth are more durable than acrylic teeth and microfill
composite teeth.
 have a higher resistance to abrasion.
composite resin artificial teeth containing nanofiller show superior color.

50. TISSUE ENGINEERING AND DENTISTRY:
Potential applications of tissue engineering and stem cell research in dentistry
include the treatment of orofacial fractures, bone augmentation, pulp repair,
periodontal ligament regeneration, and implant osteointegration.
Tissue engineering enables the placement of implants that eliminate a
prolonged recovery period,
 it is biologically and physiologically more stable than previously used
implants, and can safely support early loading.
 The main reason for preferring nanoparticles is that the range of dimension of
these structures is the same as that of cellular and molecular components.

51. FUTURE FIELDS IN DENTISTRY:
Nanotechnology will offer perfect therapeutic methods for esthetic
dentistry. All teeth that undergo treatment such as fillings or crowns will be
restored with natural biologic materials in a manner that is
indistinguishable from natural dentition.
Dentin sensitivity is another pathology that is suitable for nondental
treatment. dental nanorobots can seal specific tubules by using natural
biomaterials within a few minutes and provide a quick and permanent
recovery from this condition.
The durability and appearance of teeth can be improved by inserting
artificial materials such as sapphire or diamond into the outer layers of the
enamel with covalent bonds.