Graduate Presentations Apr 19 Mike Sherman Apr 21 Danica Nelson Aleksander Skardal Curtis Lee Apr 24 Seth Hills Ben Christensen Jungkym Kim 9/18/2018
Medical Adhesives and Sealants Frequently, presenters must deliver material of a technical nature to an audience unfamiliar with the topic or vocabulary. The material may be complex or heavy with detail. To present technical material effectively, use the following guidelines from Dale Carnegie Training®. Consider the amount of time available and prepare to organize your material. Narrow your topic. Divide your presentation into clear segments. Follow a logical progression. Maintain your focus throughout. Close the presentation with a summary, repetition of the key steps, or a logical conclusion. Keep your audience in mind at all times. For example, be sure data is clear and information is relevant. Keep the level of detail and vocabulary appropriate for the audience. Use visuals to support key points or steps. Keep alert to the needs of your listeners, and you will have a more receptive audience. 9/18/2018
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. 9/18/2018
Adhesive A substance capable of holding materials together by surface attachment (performance). A general term that includes cement, glue, mucilage and paste. 9/18/2018
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. 9/18/2018
Adhesives and Sealants-Biomaterials? Join components of medical devices-Mechanical fastening; Prevent corrosion; Fill space – smooth contours-joining prosthesis to bone; Wound sealing & closure 9/18/2018
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.) 9/18/2018
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). 9/18/2018
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. 9/18/2018
Adhesives are Polymers Thermoplastics Thermosets Available as solids, liquids and pastes and most can be supported by films of various thickness. 9/18/2018
Adhesives Acrylics Epoxies Polyurethanes Silicones 9/18/2018
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 9/18/2018
Surface Treatment No treatment (low cost poor reproducibility); Solvent wiping; Vapor degreasing; Mechanical abrasion; Plasma treatment; Etching; Chemical deposition-primers, organosilanes 9/18/2018
Modes of Failure Structural failure Adhesive failure Cohesive failure A uniform stress pattern in an adhesive joint is seldom produced by the application of external force. 9/18/2018
Urethanes Urethane polymerization-diisocyanate and a diol or diamine Condensation polymerization; Two part system- mix, spread and cure; Flexible joint and sealing agent. 9/18/2018
Poly (methyl methacrylate) PMMA R-Group Bone Cement 9/18/2018
Selection of the starting monomers C4-C12-alkyl acrylates supply the initial adhesion owing to the low glass transition temperature (Tg). 9/18/2018
Cure Profile of Condensation versus Addition Polymerization Condensation polymer Degree of Cure -----> Time 9/18/2018
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. 9/18/2018
DMSO (dimethyl sulfoxide) or acetone serve as removers. 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 removers. 9/18/2018
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. 9/18/2018
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. 9/18/2018
Light Cure Systems Designed for high speed cure on demand medical product assembly; Solvent free; and, Wide range of viscosities designed for automated dispensing 9/18/2018
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). 9/18/2018
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. 9/18/2018
Flexible Adhesive Applications Bonding/sealing tracheal tubes made of silicone rubber. Bonding/sealing extruded silicone parts, colostomy, ileostomy, urostomy bags and appliances. Sealing of inflators. 9/18/2018
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; 9/18/2018
Surgical Drapes 9/18/2018
Benefits of Adhesives Joins dissimilar materials Even stress distribution Fills large gaps Seals and bonds Easily automated Aesthetically acceptable 9/18/2018
Limitations of Adhesives Requires cure Requires fixture time Can be messy Requires chemicals in plant 9/18/2018
Substrate versatility Rapid cure Adhesion to polyolefins with primers Chemistry Benefits Limitations Typical Applications Cyanoacrylate Substrate versatility Rapid cure Adhesion to polyolefins with primers Thermoplastic resin when cured Poor peel strength, rigid Refrigeration required Catheter components Tube-set bonding Polyolefin bonding 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 9/18/2018
Applications in Dentristry 9/18/2018
ADHESIVE DENTISTRY Indications Replace carious and fractured tooth structure. Fill erosion or abrasion defects. Correct unaesthetic shapes, positions, dimensions, or shades. Cement crowns. 9/18/2018
Indications-continued Bond orthodontic brackets. Treat hypersensitivity. Repair fractured porcelain, amalgam, and resin restorations. Core build up foundations. 9/18/2018
Sealants 37% phosphoric acid for 30 seconds 2. Apply sealant 1. Etch enamel 3. Light cure PREVENTIVE DENTAL MATERIALS To prevent disease or injury to the teeth and supporting tissues Flouride gels, pit and fissure sealants, mouth protectors TOPICAL APPLICATION OF FLOURIDE Acidulated phosphate-flouride gels (Na and H flouride & orthophosphoric acid) Reduction in dentalcaries of approx 40% were observed in 2 studies of 2 years’ duration in which the gel was applied annually. PIT AND FISSURE SEALANTS A reduction in smooth surface caries has been accomplished by: Flouridation of communal water supplies topical application of fluoride during enamel development individual plaque control programs. 84% of dental caries in children ages 5 to 17 involve pits The purpose of the pit and fissure sealant is to penetrate all cracks, pits and fissures on the occlusal surfaces of both deciduous and permanent teeth to seal off these susceptible areas. Most commercial pit and fissure sealants are: - BIS-GMA (bisphenol glycidyl methacrylate) - Urethane dimethacrylate Chemistry similar to that of the dental composites Very fluid to penetrate the pits and fissures and etched areas on enamel 37% phosphoric acid for 30 seconds Courtesy of 3M Dental Products 9/18/2018
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). 9/18/2018
Enamel surface etched with 10% maleic acid gel for 15 seconds 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) 9/18/2018
Enamel surface etched with 10% maleic acid gel for 60 seconds 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). 9/18/2018
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. GLASS IONOMER CEMENTS Finely ground aluminosilicate glass Liquid is a polycarboxylate copolymer The chemical reaction gives rise to a cross-linked gel matrix Bonding to tooth tissue occurs between the polycarboxylate molecules and calcium on the surface of the tooth. There are other cements like: Zinc oxide eugenol cements Zinc polycarboxylate cements For Cementation of inlays, veneers, orthodontic bands and brackets, resin-bonded bridges etc. 9/18/2018
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 9/18/2018
Most Common Dental Resin bisphenol A glycol dimethacrylate triethylene glycol dimethacrylate 9/18/2018
Flouride Release 9/18/2018
Composites 9/18/2018
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Fractured incisors http://www.seattle-dentist.com/chipped-teeth.htm 9/18/2018
LINKMAX Packaging Self-Etching Primer EP-B 50 Yellow & 50 Pink Micro-Tips Packaging Self-Etching Primer EP-A Mixing Pad LINKMAX A3 Cartridge Ceramic Primer LINKMAX Clear Cartridge Metal Primer II Package Dispensing Dish 9/18/2018 Micro-Tip Handle Mixing Spatula
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 9/18/2018
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. 9/18/2018
• • • • BONDING PORCELAIN Etchant Etchant Ceramic Primer LINKMAX LINKMAX Self-Etching Primer Self-Etching Primer Porcelain Inlay Ceramic Primer Etchant LINKMAX Ceramic Primer LINKMAX Self-Etching Primer Self-Etching Primer Porcelain Veneer Etchant 9/18/2018
BONDING METAL PROSTHESIS TO TOOTH STRUCTURE Metal Primer II Metal Crown LINKMAX Self-Etching Primer 9/18/2018
The future Adhesive dentistry Biocompatible materials Improving the properties of adhesive materials. e.g. wear resistance, strength Biocompatible materials Antibacterial, bioactive, drug delivery Increasing use of implants Shorter healing periods Poorer quality bone Less bone Growing natural teeth 9/18/2018