Bio-Materials
meaning they are man made used to replace tissue or function in intimate contact with living tissue
dental materials
can be used for preventive or restorative purposes
heavy pressure
during scaling, the use of sonic and
ultra sonic scaling or air polishing and inappropriate
use of polishing agents may gouge or scratch the
surface of a restoration
Cavitron SofTip
Ultrasonic Implant Insert is the latest addition to the large variety of Cavitron Inserts designed for superior access and patient comfort.
The Cavitron SofTip Implant Insert removes plaque and calculus around titanium implants and abutments, allowing you
Dental materials placed and used in the oral cavity must be
biocompatible (must not impede or adversely affect living tissue)
durable
non reactive in acid or alkaline conditions
compatible with other materials
esthetically acceptable
Dental materials placed and used in the oral cavity must be
compatible
in an environment of moisture
to differing stresses / forces
to differing temperatures
to acid levels
Force & Stress
Materials must withstand varying degrees of force through the muscular action of pushing or pulling an object during mastication, bruxism, or clenching.
Normal biting force varies among individuals and from one area of the mouth to another.
Normal mastica
COMPRESSIVE FORCE
Pressure applied to compress or condense
Applies to posterior teeth
Large occlusal surfaces resist a crushing force
TENSILE FORCE
Pressure applied in opposite directions to stretch an object
When biting forces are used to stretch a material, the tooth is exerting tensile force
SHEARING FORCE
Pressure applied when two surfaces slide against each other or in a twisting or rotating motion
Eg: a ligature cutter or scissor used for cutting
STRESS
When force is exerted on a tooth, the tooth or material creates resistance to counteract the force
Amount of force exerted from within an object
strain
Distortion or deformation occurring when an object cannot resist stress
The amount of change that the force has produced
FLEXURAL STRESS
also known as bending stress. placed on the occlusal surface of a bridge bending the bridge downward and tensile forces on the tissue side of the bridge stretch upward in response
strength
Amalgam and composite resins more closely replicate enamel in compressive strength
Porcelain is more likely to fracture under compressive
FATIGUE FAILURE
During mastication, stresses occur repetitively over time.
Failures rarely occur in a single-force application
They occur when stress is frequently repeated
These repeated stresses may produce microscopic flaws that grow over time resulting in fracture
MOISTURE / ACIDITY
The oral cavity is continually in contact with moisture
This moisture varies from acid to alkaline depending on foods, beverages, medications, plaque biofilm, genetic makeup (saliva),
Normal resting pH of saliva = 6.2 to 7.0 (neutral)
It can fluctuate hig
GALVANISM
The result of the presence of dissimilar metals in the mouth along with moisture and acidity
The salts of the saliva facilitate the movement of electric current being transmitted between dissimilar metals
The phenomenon of electric current being transmitt
Thermal conductivity
is the ability of the materials to transmit
heat or cold
Thermal expansion
dental materials in the mouth are
subjected to temperature changes. If the thermal expansion
of the restoration does not match the expansion of the tooth
Micro leakage may occur
restorative materials
have different rates of expansion and contraction that differ enough from tooth structure that the marginal integrity of the restoration may be compromised
Make up the largest classification
Restores or replaces lost tooth structure, teeth, or oral tissue
percolation
continual expansion contraction
space between the tooth surface and restoration
MICROLEAKAGE
The space between the walls of the preparation and the
restoration is called the interface.
If the interface is not sealed,
fluids and microorganisms can
penetrate between tooth
structure and restorative
materials.
RETENTION
Retention may be secured through mechanical or chemical adhesion (ie: dental cements) or bonding mechanisms
Mechanical retention involves the use of undercuts or other projections into which the material is locked in place
Undercuts used in an amalgam pre
BONDING
Tooth surface is prepared with acid etch technique to create microscopic pores in enamel and dentin
Bonding materials flow into the tooth structure
Restorative materials are then placed that adhere chemically to the bonding material
BIOCOMPATIBILITY
Dental materials must be biocompatible; they must not impede or adversely affect living tissue
Materials may be acceptable for use on hard tissue but not on soft tissue
Some materials may be therapeutic in small amounts or if in contact with tissues for s
ESTHETICS
Materials in dentistry must be esthetically acceptable
Tooth color are predominantly seen in the yellow and brown range
Chroma
intensity or strength of the color
Teeth are pale in color
Value
how light or dark the color is
Teeth have value ranges in the light scale
The color of teeth is also determined by the way they reflect light
Opaque
light is completely absorbed by the object
Transparent
light passes directly through an object
DETECTION OF RESTORATIVE MATERIALS
Tooth colored restorative materials may be identified by appearance, location, tactile sensitivity, and radiographs
illumination and air aids in their identification
Tactile evaluation of the tooth surface may be the most reliable means of clinical assess
PHYSICAL PROPERTIES
Materials used in restorative dentistry need to be stiff and strong
Eg: restorations and crowns
Materials used for taking impressions are flexible and stretch a great deal
three basic forms that materials may take on
Solid
Liquid (have volume, no shape)
Gas (no definition, or volume)
Most dental materials are usually a combination of more than one form of matter
SOLIDS
Primary bonds hold solids together, giving them strength and stability. For a solid to be considered stable the crystalline structure(molecules/atoms) are arranged in a regularly spaced pattern
If the pattern are arranged in a random form with no pattern
DENSITY
Measure of weight of a dental material as compared with its volume
Measure of the compactness of matter eg: how much matter can be squeezed into a given space
The denser a material is, the less air or spacing there is between atoms
HARDNESS
The resistance of a solid to penetration or indentation
Hardness is used to define a material's resistance to wear and abrasion
Knoop Test
widely used and hardness is generally reported using this measure.
Rockwell Test
measures hardness by using a steel ball to indent the material.
ULTIMATE STRENGTH
The maximum amount of stress a material can withstand without breaking
A material does not necessarily have to break when subjected to external force; it may deform
If the deformation is not permanent and the material recovers from the force completely, i
STIFFNESS
The resistance to deformation of a biomaterial and is measured by Young's elastic modulus
Stiffer materials have a higher modulus
Example: restorative materials should have a modulus that is compatible with tooth structure
High (ME) value indicates that t
PROPORTIONAL LIMIT
The greatest stress a structure can withstand without permanent deformation
When a material is subjected to a force causing stress, the strain or change in the material that accompanies the stress is reversible up to a certain point
When stresses exceed t
RESILIENCE
The resistance of a biomaterial to permanently deform
TOUGHNESS
The ability of a biomaterial to resist fracture
MALLEABILITY
The ability for a material to be compressed without breaking
DUCTILITY
The amount of dimensional change a material can withstand without breaking
Materials with poor ductility are classified as "brittle
LIQUIDS
Molecules in a liquid state are not confined to patterns; they can flow
Viscosity
is the resistance of a liquid to flow
Thin fluids have low viscosity
Thick fluids have high viscosity
The viscosity of a liquid usually decreases as the temperature increases ie: viscosity and temperature are inversely related
Thixotropic materials
are liquids that flow more easily under mechanical forces
DIRECT RESTORATIVE MATERIALS
Materials fabricated directly in the mouth
Eg: Amalgam
Eg: Composite
INDIRECT RESTORATIVE MATERIALS
Materials fabricated indirectly outside the mouth and then placed intra-orally
Eg: Porcelain
THERAPEUTIC MATERIALS
Used in the treatment of disease
PREVENTIVE MATERIALS
Prevent occurrence of oral disease
Promote oral health
COMPOSITION
Most materials combine two components chairside to form the resulting material
2 components include:
water and powder
liquid and powder
paste and liquid
paste and paste
paste and initiator
NOTE: Many components are classified as catalyst and base; the cat
REACTION
A reaction occurs when components are mixed together
Most reactions of the two components result in a solid structure
The reaction may be physical or chemical
Dental material goes through stages before it reaches its ultimate state
Manipulation Stage
mixing and working time
Reaction Stage
initial and final set
MIXING TIME
The amount of time the operator has to bring the components together into a homogeneous mix
WORKING TIME
The time permitted to manipulate the material in the mouth
INITIAL SET TIME
This time begins when the dental material no longer can be manipulated in the mouth
FINAL SET TIME
The material has reached its ultimate state
CHEMICAL-SET MATERIALS
Set through the timed chemical reaction of the catalyst and base
Eg: periodontal dressing (Coe-Pack)
LIGHT-ACTIVATED MATERIALS
Set by using a blue light
Eg: composite resins
DUAL-SET MATERIALS
Begin with the initial blue light source and then continue with a chemical-set reaction
MANIPULATION
Dental materials should be measured and dispensed according to the manufacturer's recommendations
Changing the ratios of the materials by adding more catalyst (accelerator) may result in a faster reaction
Increasing the amount of liquid or water may resul
IMPRESSION MATERIAL
Impression materials are used to make replicas (models / casts) of teeth restorations and preparations made for restorative treatments and other supporting oral tissues both hard and soft including: a)gingiva
b)max- acurate soft palate c) acurate hard pal
Formation
chemical physical change (sol - liquid)
IDEAL MATERIAL
ease of manipulation
reasonable cost
appropriate setting time and characteristics
accuracy in clinical use
sufficient mechanical strength
dimensional stability
non-toxic or irritating
acceptable to the client
readily disinfected
compatible with die and ca
HYDROCOLLOIDS
water based colloids that function as elastic impression materials
Sol
liquid state in which colloidal particles are suspended, by cooling or chemical reaction it can change into a gel
Gel
a semisolid state in which colloidal particles form a framework that traps liquid ( e.g. Jell-O)
AGAR
80% - H2O
8 - 15% - agar-agar (form seaweed)
colorants
flavors
Potassium sulfate
Borax
Alkyl benzoate
reversible hydrocolloid
ALGINATE
Sodium alginate
Calcium sulfate dehydrate
diatomaceous earth
colorant
flavor
Inhibitors
Potassium sulfate
Trisodium phosphate (controls rate of setting - regular or fast set)
REVERSIBLE HYDROCOLLOID
They have been used for over 60 years
One of the most popular type of elastic impression materials
Take accurate impressions of teeth and tissue with undercuts
Main use for impressions of operative and crown and procedures
IRREVERSIBLE HYDROCOLLOID
alginate hydrocolloid is the most widely used impression material
change from a sol phase to a gel phase via chemical reaction and cannot be reversed
not accurate enough for final impressions
IRREVERSIBLE HYDROCOLLOID Advantages
good for subgingival impression
working in a "wet" environment
pouring models
IRREVERSIBLE HYDROCOLLOID disadvantage
shrinkage - syneresis
swelling - imbibition
poor tear strength
client care - burning "tissues
CRITERIA FOR AN ACCEPTABLE ALGINATE IMPRESSION
all teeth and alveolar processes
peripheral roll and frenums
no large voids, few small air bubbles
good reproduction of detail
free of debris
no distortion
attached firmly to tray
Maxillary
palatal vault and hamular notch
Mandibular
retromolar areas and lingual extensions
TAKING AN ALGINATE IMPRESSION
Objective
Tray Selection- kids vs adult, med,lg
Dispensing
Mixing - water, then powder
Loading- back to front, man- lingual 2 increments
Seating- placing in patient mouth.
Removal- snap DO NOT rock
Handling
How to control gag reflex... - breath through no
TROUBLESHOOTING ALGINATE IMPRESSIONS
Premature set
Slow set
Grainy mix
Incomplete coverage of teeth / tissues
Voids / Bubbles
Distortion
Torn
Excess alginate
ELASTOMERIC MATERIAL
used where teeth are present and material flexibility is needed for removal from the oral cavity or teeth
used for impressions of preparations and for demanding or highly accurate reproductions
they have qualities similar to rubber
they are composed of a
POLYSULFIDE
material will harden or set by means of chemical reaction
relatively stable
accurate impression (98% retention)
greater tear strength
used for crown and bridge, partial and complete denture
unpleasant taste, odor, stains clothing
adversely affected by hea
mercaptan" rubber or rubber base
oldest of the elastomers also known
SILICONE MATERIAL
designed as improvement over polysulfide impression material
viscosity less than polysulfide - easier to mix
a special adhesive is used to provide retention to custom tray
available as addition reaction and condensation reaction
available as light, regula
CONDENSATION SILICONE
it was developed as an alternative to polysulfide
two paste system or paste-liquid
easy to mix, pleasant tasting, odorless
shorter working and setting times
mixing reaction causes ethyl alcohol to form and be released causing shrinkage of the impression
u
ADDITION SILICONE
This is an improvement over the condensation silicone materials
two paste system
no by products are formed during mixing
lowest dimensional change of any of the rubber impression material
more dimensional stability and accuracy
clean and easy to use, with
POLYETHER
possible good alternative to polysulfide impression material
very accurate
used in crown and bridge preparations
more hydrophilic than other elastomers
available in light, medium, and heavy viscosity
stiffest of all the elastomers
difficult to remove from
IMPRESSION TRAYS
manufactured in several form stock trays: Rim Lock, Perforated and Custom Made stock trays
variety of sizes
perforated trays allow for the flow of alginate through the perforations and lock alginate into the tray
rim lock trays have a small rim around the
Gypsum
products are used mainly for making positive
reproductions or replicas of oral structures, often referred to as
casts, dies or models.
Gypsum is a mineral found in nature in various parts around the
world known as calcium sulfate dihydrate and has been us
Gypsum powder products
produced by heating gypsum and driving off part of the water of crystallization by a process called
calcination
resulting product is known as calcium sulfate
hemihydrate.
exothermic reaction
by-product of the chemical reaction is heat
Casts
hard replicas of hard and soft tissue of the patient's oral cavity made from gypsum products; often referred to as models
Diagnostic Casts:
generally made from dental plaster or stone and used for patient education, treatment planning, and tracking the progress of treatment, as with orthodontic models
poured in plaster because of the low need for physical properties AKA: Model Plaster, Labora
Working Casts
casts generally made from one of the dental stones that are strong enough to resist the stresses of fabricating an indirect restoration or prosthesis
require good strength and accuracy and are poured in dental stone
Dies
replicas of prepared teeth that are generally removable from the working cast
require dimensional accuracy and strength and poured in high strength stone AKA: Improved Dental Stone
Strength of gypsum
related to the amount of water used in producing the "model"
A product with less water has a higher density of crystals and is therefore a denser and stronger product
ACCURACY
setting expansion occurs with all gypsum products
plaster @ 0.30% - high strength stone @ 0.10%
occurs as crystals join
The control of setting expansion is critical for accurate models and dies
It is important that expansion be held to a minimum eg; if ex
DETAIL
The greater the porosity of the gypsum product the less surface detail is reproduced
Compatibility of impression materials and die materials can influence your quality of surface reproduction
Silicone and polyether form the best surface detail with gypsum
SOLUBILITY
Set gypsum products are not highly soluble in water
The more porous the gypsum the more soluble the material is
Do not expose models to water for a long period of time
PLASTER (TYPE I)
Rarely used today and has been replaced with less rigid , elastic impression material
MODEL PLASTER (TYPE II)
Processed in open vats @ 115oc
Powder consists of porous, irregular particles
Used where strength is not a critical requirement
Used to secure casts to the articulator or preliminary casts
White in colour
Available in regular and fast set
Frequently used
DENTAL STONE (TYPE III)
Made by carefully controlled calcination under steam pressure in a closed container and a higher temperature
Material more uniformed in shape and less porous
Stone is stronger and more expensive than plaster
Ideal for making casts for complete and partial
HIGH STRENGTH (TYPE IV)
Produced by calcining the gypsum in a 30% calcium chloride solution with increased pressure and powder grinding
Material is very dense and cuboidal in shape
AKA: die stone
Used for making casts or dies for inlay and crowns
Pink or green in colour
EXPANSION (TYPE V)
Developed in response for the need for higher strength and high expansion dental stones due to greater casting shrinkage of newer bas metal used for dental castings
Recent addition to the list of ADA gypsum products
Available in blue or green
Most costly
WATER / POWDER RATIO
Model Plaster
45 ml of H2O : 100 grams of plaster
Dental Stone
30 ml of H2O : 100 grams of stone
High Strength Stone
23 ml of H2O : 100 grams of stone
High Strength / Expansion Stone
20 ml of H2O : 100 grams of stone
MANIPULATION 2
Water aids in wetting and helps the material flow
Powder is sifted into the water to help prevent clumps forming
Water evaporates as the gypsum product sets (exothermic reaction)
Room temperature water or cooler
The measured amount of water is placed into
INITIAL SETTING TIME - WORKING TIME
After mixing for 1 minute, the working time begins
In this time, the semifluid mixture is poured into the impression using a mechanical vibrator
As the viscosity of the mixture increases, the material will no longer flow and loses its glossy appearance
Fo
FINAL SETTING TIME
When the material can be separated from the impression it has minimal hardness and resistance to abrasion
Usually between 45 - 60 minutes
Models will be cool and dry (completed exothermic reaction)
Two to three times harder after 24 hours
DOUBLE POUR
The anatomic portion of one or both arches is poured and left in the upright position
After approximately 10 minutes, a second mix is produced
This mix is placed on a glass tile or base former
The filled impression is inverted onto the base and the periph
SINGLE-STEP
One mix of gypsum is produced to pour the anatomic and art portions of the cast
After pouring the impression, the remaining material is used for the base
This material is placed on a glass tile or in a base former, the impression is inverted onto it, and
BOXING
Boxing was is used to surround the impression, forming a wall into which the gypsum is poured
The wax should not distort the impression
It should extend .5 inches higher than the highest point of the impression
The base should be parallel to the occlusal
EVALUATION OF DIAGNOSTIC CASTS
Anatomic and art portion is free of air voids
The union between art and anatomic portions forms a continuous surface
The occlusal plane is parallel to the bottom of the base and the base is of adquate thickness
There is sufficient material extending past
TRIMMING
Produces an attractive and symmetric model
Provides a base of sufficient bulk for stability
Bases should be soaked in water for 5 to 10 minutes before trimming to saturate the stone making it easier to trim
Exercise care when using the model trimmer
Alway
EVALUATION OF TRIMMED DIAGNOSTIC CASTS
Anatomic portion makes up 2/3 of total depth
Base portion makes up 1/3 of total depth
Bases should be parallel with the occlusal plane
Posterior portions of retromolar pad is visible
Posterior portions of maxillary tuberosity is visible
Side and anterior
PROVISIONAL COVERAGE
AKA: TEMPORARIES
A restoration that temporarily occupies the place of a permanent restoration, usually 3 weeks.
In complex prosthodontic, pedodontic and endodontic cases, provisional restorations can last for longer period of time
The increased demand for
PREFORMED CROWNS
This method is time saving eg: in an emergency situation if the client presents a fractured tooth
This method does not consistently produce successful temporization
Since the prepared tooth is much smaller than preformed shell, a reline (acrylic/composite
STAINLESS STEEL CROWNS
Most durable - lasts months or years
Generally used to restore primary teeth
Adv: malleability, marginal integrity, occlusion
ALUMINUM SHELL CROWNS
Used for posterior teeth
Lined with acrylic/composite
Cemented with temporary cement
Softness - allows for easy manipulation of contact, occlusion and margins but can contribute to wear
Adapted using crown and bridge scissors
POLYCARBONATE CROWNS
Classified as being rigid - adapted with acrylic burs and discs
Indicated for anterior teeth-aesthetically pleasing
CELLULOID CROWN FORMS
Clear forms which are filled with acrylic or composite which match tooth shade and then inserted onto prepared tooth
The form is initially cut using crown and bridge scissors to fit the tooth
Small holes are placed on occlusal surface to allow excess mate
CUSTOMIZED PROVISIONALS
Allows for better fit and function
Allows multi-unit temporary bridges
Improves client satisfaction due to superior aesthetics
DIRECT TECHNIQUE
Provisional is fabricated directly on the tooth
A template is obtained prior to preparation
The template is then filled with material and reinserted into the mouth
Eg: acrylic and composite provisional crown materials in hand mix or automix
INDIRECT TECHNIQUE
The template is made on the study model
The fabrication of the provisional is usually done on the model
Eg: silicone putty, thermoplastic wax, vacuum-formed plastic templates
PROSTHETIC DENTISTRY
Involves the restoration or replacement of missing tissues or teeth.
A good prosthetic device should maintain tooth position, function, appearance, and protect both hard and soft oral structures.
REPLACING MISSING TEETH
An important step in maintaining a healthy smile is to replace missing teeth
When teeth are missing, the remaining ones can change position, drifting into the surrounding space
Teeth that are out of position can damage tissues in the mouth
In addition, it
CROWN
AKA: CAP
The dental crown procedure utilizes tooth-shaped coverings made of metal, ceramic, or porcelain to restore strength and eliminate discomfort
Indications for crown according to CDA:
1) a tooth that has had endodontic therapy
2) a tooth that is hea
METAL CROWNS
Although their metallic color makes them a poor choice for highly visible teeth, dental crowns made of metal can be an ideal option for repairing decayed or damaged back teeth.
They are extremely durable and can be applied with less removal of the natural
CERAMIC CROWNS
All ceramic crowns may be made of porcelain, resins, or dental ceramic materials.
They create an extremely natural-looking appearance and are typically used on front teeth.
The tooth-colored ceramic material is translucent, like the enamel of your natural
PORCELAIN FUSED TO METAL CROWNS
Dental crowns made of porcelain fused to metal are stronger than all-ceramic versions and more aesthetically pleasing than those made of metal
However, their metal shell gives porcelain fused to metal crowns an opaque appearance
Because they lack the refl
POST & CORE CROWN
Placing a Post and Core is a procedure that is required in order to rebuild and strengthen a tooth that had root canal treatment
It adds the proper support necessary to restore a tooth with a crown
The post is a metallic or reinforced fiber structure that
CAPTEK
an advanced metallurgic technology for producing high hold metal substructures for crowns and bridges
It produces precision fitting copings for all conventional crowns, bridges, inlays and onlays
Benefits include outstanding aesthetics, high biocompatibil
DENTAL IMPLANTS
usually made out of titanium
Dental implants are the preferred method to replace single or multiple missing teeth, even partial or full dentures.
Dental implants do not involve the preparation of natural teeth and are considered to be a more conservative
BRIDGE
A fixed bridge refers to a prosthesis that will span the area of a missing tooth, known as a pontic.
The procedure involves the preparation of two or more abutment teeth.
Once this has been accomplished, an impression is made and sent to the dental labora
VENEERS
Veneers are very thin and are bonded on the front of anterior teeth
Dentists use some of the same techniques to bond plastic resins for minor smile corrections
Veneers are about 0.3mm to 0.5mm in thickness but are very strong once bonded to the teeth
They
VENEERS CAN BE DONE:
1) to close spaces between the teeth (diastemas)
2) to whiten dark yellow or stained teeth
3) to restore broken or chipped teeth
4) to restore stained or washed out restorations
5) to enhance permanently stained or discolored teeth
6) to correct crooked t
ADVANTAGES OF VENEERS OVER CROWNS
1) There is no "dark line" that is sometimes seen with older anterior crowns
2) They transmit light better and, therefore, have a more translucent appearance giving a natural, esthetic look
3) They do not require massive grinding of tooth structure
PARTIAL DENTURE
A partial denture is a removable dental appliance that replaces multiple missing teeth
It can be attached to the teeth with clasps (clasp or conventional partial) or it can be attached to the teeth with crowns with precision attachments (hidden clasps)
Bo
COMPLETE DENTURES
A complete denture replaces all the teeth
Complete dentures are either conventional or immediate
A conventional denture is placed in the mouth about a month after all the teeth are removed to allow for proper healing
An immediate denture is placed as soon
INLAY
similar to a filling and lies inside the cusp tips of the tooth
They are custom-made to fit the prepared cavity and are then cemented into place
Dental inlays are used to treat teeth that have decay or damage lying within their indented top surfaces
They
ONLAY
Onlays are made of a strong, natural-looking material, such as porcelain
Onlays are larger restorations, extending over one or more sides of your tooth, and can be used similar to a crown
A conservative tooth restoration that requires far less tooth remov