GC EUROPE Unifil Bond User Manual

Technical Manual
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GC UniFil Bond Technical manual v ersion 1.10, November 2005, 1/23
Table of contents
1.0 Introduction ………………………………………………………………………. 3
2.0 Currently available adhesion concepts ……………………….. 3
3.0 Composition ………………………………………………………………………. 5
Initiators used ……………………………………………………………………… 5 Silica ……………………………………………………………………………………… 6
4.0 Application …………………………………………………………………………. 6 Self-Etching Primer …………………………………………………………….. 6 Bonding Agent .……………………………………………………………………. 6
5.0 Adhesion mechanism ………………………………………………………. 7 Self-etching primer / 4 – MET …………………………………………….. 7 Bonding agent ………………………………………………………………………. 8
6.0 Test results …………………………………………………………………………. 9 IR analysis ……………………………………………………………………………… 9 XPS analysis ………………………………………………………………………….. 9 Tensile Bond strength ……………………………………………………………. 10 Consequence of technique variables ……………………………………. 11 Consequence of variables in tooth structures ……………………… 12
7.0 Clinical investigations ………………………………………………………. 14
8.0 Literature …………………………………………………………………………….. 15
9.0 Packaging ……………………………………………………………………………. 21
10.0 Instructions for use …………………………………………………………… 22
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1.0 Introduction
The development of GC UniFil Bond is the result of GC’s commitment to understanding and seeking solutions to the variable success parameters currently restricting certain indications for composite resin restoratives.
While long-term success has been achieved with composite resin bonded to all enamel surfaces, the same cannot be said for bonded composite where margins are in dentine. Composite restoration failure often occurs at the interface between the composite and dentine leading to staining, microbial leakage and progression of caries.
Improvements therefore focused on solutions to the problems experienced at this interface. The many causes of interface failure include application factors (variable placement techniques, over etching, over drying, fluid contamination, surface contaminants like excess acetone), site factors (variable dentin structure i.e. tubule orientation, degree of mineralization) and stress factors (occlusal loading, tooth flexure, polymerization shrinkage stress and variable coefficients of thermal expansion).
GC UniFil Bond was developed seeking to provide solutions to many of these problems and focused on three primary objectives:
Provide strong adhesion via simple application procedures with minimal
opportunity for compromised results caused by technique variation
Provide strong adhesion to a wide variety of dentine surfaces
Maintain an effective seal by utilizing both micromechan ical int erlocking and chemical adhesion.
2.0 Currently available adhesion concepts
At present several adhesion concepts are considered for bonding to tooth surfaces. The adhesion mechanisms are divided into three major categories
- micromechanical interlocking
- chemical (ion-exchange) adhesion
- combination of above two
Micromechanical interlocking is achieved by etching both enamel and dentine
surfaces followed by application of resin bonding systems that contain functional monomers with both hydrophilic and hydrophobic groups. These monomers are able to penetrate and diffuse throughout the etched dentine surface layer to form a hybrid zone that adheres to the dentin surface. Strong micromechanical interlocking to enamel is also achieved where the resin penetrates the irregularities in the etched enamel surface forming micro resin tags.
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Mechanical retention due to resin tag formation
Chemical adhesion is the main mechanism by which glass ionomer cements are
bonded to dentine and enamel surfaces. The carboxyl group (COOH) of polyalkenoic acids (the liquid component of glass ionomer cement ) is ionized by reaction with powder into carboxylic acid ions (COO strong ionic bonds with calcium ions (Ca
2+
) in the tooth apatite. The adhesion is
-
). These ions have extremely
so strong that laboratory testing often shows cohesive failure within the cement rather than adhesive failure at the interface. Class V retention studies have shown that long term stability of this adhesion is clinically relevant.
Chemical adhesion of glass ionomers to tooth structure
A combined chemical adhesion / mechanical interlocking can be observed by
using resin reinforced glass ionomers in combination with the appropriate conditioners. These resin reinforced glass ionomer cements have grown quickly in popularity as highly successful adhesive materials for crown and bridge cementation (GC Fuji PLUS), composite lining and bonding (GC Fuji Bond LC ) and for orthodontic bonding of brackets and bands (GC Fuji ORTHO LC).
GC Fuji BOND LC GC Fuji PLUS GC Fuji BOND LC Interface with dentine Interface with dentine Interface with dentine
GC UniFil Bond represents the result of GC’s application of glass ionomer adhesion concepts into an advanced, user-friendly, resin bonding system.
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3.0 Composition
SELF-ETCHING PRIMER WT% 4-Methacryloxyethyl trimellitic acid (4-MET) Ethanol 48 Distilled water 40 HEMA 2 Initiator Trace
BONDING AGENT WT% UDMA 50 TEGDMA 30 HEMA 16 Silica Filler 4 Initiator Trace
Initiators used In GC UniFil Bond, a combination of camphorquinone and amine is used as the
catalyst. Light activation can be carried out with quartz halogen, plasma or LED curing units. To reinforce the outer enamel surface and the collagen network with a firm and stable adhesive resin layer it is crucial that monomers from both the primer and bonding agent are converted from a liquid into a solid state. When the initiators, as in GC UniFil Bond, are contained in both the primer and bonding agent solut ions, the co-polymerization of available monomers occurs more efficiently than when contained only in either one of the solutions. Although in the latter case the initiator might diffuse through both the primer and bonding agent immediately after coming into contact with each other, it is preferable that both liquids include the initiator separately.
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Silica Colloidal silica is added to control the flow of the bonding agent. This will ensure that
the operator has a better control during the application. In addition to this practical advantage, a slight increase in the modulus of elasticity could be obtained – 2.8 (0.1) GPa with silica, versus 2.6 (0.1) GPa without.
4.0 Application
Self – etching primer
Apply GC UniFil Bond self-etching primer to the dentine and enamel surfaces and leave undisturbed for 20 seconds. Then gently dry with an air syringe for 5 seconds and ensure that the primed surface has a glossy appearance. Do not rinse with water.
Bonding agent
GC UniFil Bond bonding agent is immediately applied to the primed enamel and dentine surfaces. Then gently dry with an air syrin ge to form a thin film and light cure for 10 seconds. GC GRADIA DIRECT composite can now be applied to the treated surface.
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5.0 Adhesion mechanism
At the heart of GC UniFil Bond’s performance is the 4-MET molecule in the primer solution. 4-MET is derived from 4-META by hydrolysis during the manufacturing process and compared to the latter is more hydrophilic and acidic. The functional monomer 4­MET is characterized by self etching and adhesive properties and inherently has very good diffusion properties.
4-MET
Self-etching primer / 4 - MET As can be seen from the figure below, the carboxyl group (COOH) of 4-MET can
dissociate into hydrogen (H
+
) and carboxylic (COO-) ions.
Dissociation of 4-MET when applied to tooth surfaces
This dissociation will result in both (self) etching of tooth surfaces and chemical adhesion to calcium.
Self-etching properties
Both enamel and dentine surfaces will be decalcified due to the freely availabl e hydrogen ions and consequently dissolution of the outer surfaces (1µm) of the hydroxyapatite will take place. The pH of GC UniFil Bond Primer is 2.0.
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