Transcript Document

Graduate Presentations
Apr 19
 Mike Sherman
Apr 21
 Danica Nelson
 Aleksander Skardal
 Curtis Lee
Apr 24
 Seth Hills
 Ben Christensen
 Jungkym Kim
7/17/2015
1
Medical
Adhesives
and Sealants
7/17/2015
2
Adhesion
Definition:
The state at which two surfaces are held together by
interfacial forces, which may consist of all known
chemical attractive forces, as well as mechanical
interlocking action or both.
7/17/2015
3
Adhesive


A substance capable of holding materials together by
surface attachment (performance).
A general term that includes cement, glue, mucilage and
paste.
7/17/2015
4
Sealant

A material applied to a joint in paste or liquid form that
hardens or cures in place, forming a barrier against gas
or liquid entry.
7/17/2015
5
Adhesives and SealantsBiomaterials?




Join components of medical devices-Mechanical
fastening;
Prevent corrosion;
Fill space – smooth contours-joining prosthesis to bone;
Wound sealing & closure
7/17/2015
6
Adhesive Materials can be
classified in a number of ways:





Natural or synthetic polymer base;
Thermoplastic or thermosets;
Physical form (one or multiple component, films, etc)
Functional type (structural, hot melt, pressure sensitive;
Chemical families (epoxy, silicone, etc.)
7/17/2015
7
General Considerations in the
Application of Adhesive Bonding





When applied adhesives have to 'wet' the surface;
They need to be mobile and flow into all the tiny surface
features of the substrate;
If the adhesive does not wet the substrate well, poor
adhesion is likely to be the result;
Once good wetting takes place, an adhesive needs to
become solid and not flow at all. This is called setting or
curing (polymerization); and,
Positional indication (imaging).
7/17/2015
8
Adhesive Joint
Breaking strength is determined by:
 Mechanical properties of the materials of the joint;
 The extent of the interfacial contact (number, extent, type
and distribution of voids);
 Presence of internal stresses;
 The joint geometry; and,
 The details of mechanical loading.
7/17/2015
9
Adhesives are Polymers



Thermoplastics
Thermosets
Available as solids, liquids and pastes and most can be
supported by films of various thickness.
7/17/2015
10
Adhesives




Acrylics
Epoxies
Polyurethanes
Silicones
7/17/2015
11
Bonding Mechanisms




Mechanical Interlocking;
Formation of covalent bonds across the interface;
Electrostatic attraction-dominant
Forces are not significant beyond 0.5 nm-therefore
contact is necessary
7/17/2015
12
Surface Treatment







No treatment (low cost poor reproducibility);
Solvent wiping;
Vapor degreasing;
Mechanical abrasion;
Plasma treatment;
Etching;
Chemical deposition-primers, organosilanes
7/17/2015
13
Modes of Failure
A uniform stress pattern in an adhesive joint is seldom
produced by the application of external force.

Structural failure

Adhesive failure

Cohesive failure
7/17/2015
14
Urethanes




Urethane polymerization-diisocyanate and a diol or
diamine
Condensation polymerization;
Two part system- mix, spread and cure;
Flexible joint and sealing agent.
7/17/2015
15
Poly (methyl methacrylate)
PMMA
R-Group
7/17/2015
Bone Cement
16
Selection of the starting
monomers

C4-C12-alkyl acrylates supply the initial
adhesion owing to the low glass transition
temperature (Tg).
7/17/2015
17
Degree of Cure ----->
Cure Profile of Condensation
versus Addition Polymerization
Addition polymer
Condensation
polymer
Time
7/17/2015
18
Methyl 2- cyanopropanoate
R-Group
Methyl -cyanoacrylate monomer polymerizes in the presence
of trace amounts of almost any electron-donor compound (the
initiator) by anionic vinyl polymerization, examples include
water, alcohols, amines, carboxylate ions, and electron rich
olefins.
7/17/2015
19
• Medical grade products currently available contain
either butyl, isobutyl or octyl esters. They are
bacteriostatic and painless to apply, break down
harmlessly in tissue by hydrolysis and are essentially
inert once dry.
•Butyl products are rigid when dry, but provide a strong
bond; octyl products are more flexible when dry, but
produce a weaker bond.
•Histoacryl Blue (n-butyl cyanoacrylate) has been used
extensively for a variety of surgical applications
including middle ear surgery, bone and cartilage grafts,
repair of cerebrospinal fluid leaks, and skin closure -adhesives appear are basically safe.
• DMSO (dimethyl sulfoxide) or acetone serve as
7/17/2015
removers.
20
The Market




The global medical and surgical sealant market is $542
million and growing rapidly (19% annually), driven
particularly in the U.S.
Adhesives and sealants are a critical component of
medical devices.
As medical devices become smaller and more complex,
greater demands are being made on the materials and
components used in them.
Medical devices are being exported from the U.S. to
foreign countries at an increasing rate.
7/17/2015
21
Considerations


speed of application;
This is an area where UV-curable adhesives have made
the strongest technological advances of any of the newer
technologies currently on the market.
7/17/2015
22
Light Cure Systems



Designed for high speed
cure on demand medical
product assembly;
Solvent free; and,
Wide range of viscosities
designed for automated
dispensing
7/17/2015
23
Light Cure Adhesives




consist essentially of low or medium molecular weight
resins (called oligomers), monofunctional or
multifunctional monomers, photoinitiators and/or
photosensitisers;
wavelengths of 250-365nm.
typically 5-15 seconds at 80-100 mW/cm2 is sufficient for
curing adhesive
visible light curing materials (e.g. resins used in dental
restoration or for bonding and sealing photo-optic
devices) can be cured with blue light (wavelength =
470nm).
7/17/2015
24
Typical Applications




Bonding latex balloon onto
PVC lumen in catheters.
Bonding high pressure latex
balloons onto urethane
lumens in high pressure
catheters, catheters for
angioplasty, thermodilution,
or foley catheters.
Bond needle to tubing in
winged infusion sets
Hypodermic needle.
7/17/2015
25
Flexible Adhesive Applications



7/17/2015
Bonding/sealing tracheal
tubes made of silicone
rubber.
Bonding/sealing extruded
silicone parts, colostomy,
ileostomy, urostomy bags
and appliances.
Sealing of inflators.
26
Pressure-Sensitive Adhesives





Arcylics on PET
Labels-many medical devices require a label that can be
printed after the adhesive has been applied and/or can
be written on after application to the device.
Adhesive tapes for attaching equipment drapes in sterile
environment applications.
Lidding-effective protective barrier against contamination
for storage or shipping;
EKG electrode bonding;
7/17/2015
27
Surgical Drapes
7/17/2015
28
Benefits of Adhesives






Joins dissimilar materials
Even stress distribution
Fills large gaps
Seals and bonds
Easily automated
Aesthetically acceptable
7/17/2015
29
Limitations of Adhesives




Requires cure
Requires fixture time
Can be messy
Requires chemicals in plant
7/17/2015
30
Chemistry
Benefits
Limitations
Typical Applications
Thermoplastic resin
when cured
Poor peel strength,
rigid
Refrigeration
required
Catheter components
Tube-set bonding
Polyolefin bonding
Cyanoacrylate
Substrate versatility
Rapid cure
Adhesion to
polyolefins with
primers
Light-Curable
Acrylic
Substrate versatility
Good resistance
properties
Cure on demand
Capital expenditure
for light-cure
equipment
Needle assembly
Anesthesia masks
Heat exchangers
Oxygenators
Tube-set bonding
Epoxy
Substrate versatility
Superior thermal
and chemical
resistance
Low shrinkage
High gap filling
Poor peel strength,
rigid
Exothermic reaction
Two-part systems
require mixing
Needle assembly
Deep section potting
Polyurethane
Substrate versatility
High peel
Good resistance
properties
Moisture sensitivity
Primers required for
some substrates
Two-part systems
require mixing
Deep section potting
Bonding of tips onto
various components
7/17/2015
31
Applications in Dentristry
7/17/2015
32
ADHESIVE DENTISTRY
Indications
 Replace carious and fractured tooth structure.
 Fill erosion or abrasion defects.
 Correct unaesthetic shapes, positions,
dimensions, or shades.
 Cement crowns.
7/17/2015
33
Indications-continued




Bond orthodontic brackets.
Treat hypersensitivity.
Repair fractured porcelain, amalgam, and resin
restorations.
Core build up foundations.
7/17/2015
34
Sealants
2. Apply sealant
1. Etch enamel
37% phosphoric
acid for 30
seconds
3. Light cure
Courtesy of 3M Dental
Products
7/17/2015
35
Enamel surface etched with 35% and 10%
phosphoric acid gels for 15 and 60 seconds.
Areas with preferential removal of prism core
material and the prism peripheries relatively
intact (SEM X2000).
7/17/2015
36
Enamel surface etched with 10% maleic acid
gel for 15 seconds. The apatite crystals were
partially removed from the prism core, but the
type I etching pattern may be observed (SEM
X2000)
7/17/2015
37
Enamel surface etched with 10% maleic acid
gel for 60 seconds. The topographical view of
the prism core structure is similar to the
etching patterns produced by 35% and 10%
phosphoric acid gels (SEM X2000).
7/17/2015
38
Glass-ionomers
• Most commonly referred to as glass ionomer cements
(GIC's).
• These are materials which consist of an aqueous
polyacrylate and a fluoroaluminosilicate glass.
• These set by an acid-base reaction in the presence of
water.
• These cements appear to adhere to tooth structure by
formation of ionic bonds as a result of chelation of the
carboxyl groups in the acid with the calcium and/or
phosphate ions in the apatite of enamel and dentin.
7/17/2015
39
COMPOSITION
POWDER = CALCIUM
FLUOROALUMINOSILICATE GLASS
 Silicon
13.3%
Phosphorus 2.5%
 Aluminum
13.3%
Fluoride
22.7%
 Calcium
17.3%
Oxygen
28.0%
 Sodium
1.6%
 LIQUID = POLYACRYLIC ACID OR
 COPOLYMER OF ACRYLIC ACID
 WATER
7/17/2015
40
Most Common Dental Resin
bisphenol A glycol dimethacrylate
triethylene glycol dimethacrylate
7/17/2015
41
Flouride Release
7/17/2015
42
Composites
7/17/2015
43
7/17/2015
44
7/17/2015
45
Fractured incisors
http://www.seattledentist.com/chippedteeth.htm
7/17/2015
46
50 Yellow & 50 Pink
Self-Etching Primer Self-Etching Primer
Micro-Tips
EP-B
EP-A
LINKMAX
Packaging
Mixing Pad
LINKMAX A3
Cartridge
Ceramic Primer
LINKMAX Clear
Cartridge
Dispensing Dish
Metal Primer II
Package
7/17/2015
Mixing Spatula
Micro-Tip Handle
47
Paste Pak Dispenser
• Produces Ideal Consistency Every Time.
• Dispenses The Exact Mixing Ratio No Matter How Little Or
How Much Material Dispensed.
• Metering Slide Enables The User To Control The Volume Of
Material Dispensed To Reduce Waste.
More
Less
7/17/2015
48
Dual Cure: Light Cure & Self Cure
• Temporary Light-Cured Linkmax Removes Easily With Hand
Instrument One Minute After Seating.
• No Radical Clean-Up Procedure Should Be Required.
• Light-Cure Each Surface Of Restoration 20 Seconds.
• When Used Under Metal Or When Cement is Difficult To Expose
To Light, Linkmax Self-Cures In 6 Minutes From Placement Of
Prosthesis.
7/17/2015
49
BONDING PORCELAIN
•
••
•
Etchant
Etchant
Ceramic Primer
LINKMAX
Self-Etching Primer
Ceramic Primer
LINKMAX
Self-Etching Primer
Porcelain Inlay
Ceramic Primer
Etchant
LINKMAX
Ceramic Primer
LINKMAX
Self-Etching
Primer
Porcelain
Veneer
7/17/2015
Self-Etching
Primer
Etchant
50
BONDING METAL PROSTHESIS TO TOOTH STRUCTURE
Metal
Primer II
Metal
Crown
LINKMAX
SelfEtching
Primer
7/17/2015
51
The future

Adhesive dentistry


Biocompatible materials


Antibacterial, bioactive, drug delivery
Increasing use of implants




Improving the properties of adhesive materials. e.g. wear
resistance, strength
Shorter healing periods
Poorer quality bone
Less bone
Growing natural teeth
7/17/2015
52