Bonding

10.1055/b-0034-75534

Bonding

With regard to bonding brackets, there are generally no differences between the various ligation methods, and the same selection criteria for bonding agents therefore apply.

Bonding to the natural tooth surface. Bonding to healthy enamel is a standardized procedure that involves either mechanical bonding (acid-etch technique) or chemical bonding (glass ionomer cements), or a combination of the two components ( Table 6.2 ).

Increase in bond strength. Bonding in difficult conditions (e.g., when there is poor enamel quality, alterations in the enamel surface, deciduous teeth, composite restorations, or when moisture control is difficult) may require an adhesion booster such as Enhance (Reliance Orthodontics), which has been on the market for many years and has more recently been replaced by Assure. According to the manufacturer, this product increases the bond strength and has a greater fluoride content. Maximum Cure and Pro Seal (also Reliance Orthodontics), are also sealers but have a higher filler content than Assure and are therefore useful for sealing the tooth surface surrounding the bracket. Both products supposedly have protective characteristics, while at the same time providing bond strength comparable to that of other primers not featuring fluoride protection. The fluoride-releasing sealant is intended to protect the teeth over a 2-year period, which normally covers the duration of fixed appliance treatment.

Priming of previously filled or altered tooth surfaces. Due to the increasing numbers of adults who are seeking orthodontic treatment, orthodontists are more interested than ever to develop bonding strategies for teeth that have previously been filled with either composite, ceramic, or metal restorations. Bonding to composite almost always requires preparation of the previously polished surfaces. A chemical bond can be achieved by using a polymer conditioner (Plastic Conditioner; Reliance Orthodontics, see Table 6.3 ).

It is often necessary to bond to ceramic restorations such as veneers or crowns. The bonding techniques are similar to the bonding protocols for ceramic inlays and prosthetic restorations in restorative dentistry ( Table 6.4 ). It is often necessary to roughen the surface of metal restorations before bonding. Conditioners to increase the bond strength to metal restorations are known as metal primers (Metal Primer; Reliance Orthodontics, see Table 6.5 ). Bonding protocols for the various types of surfaces are described in Table 6.6 .

Table 6.2

Bonding to enamel

 

Mechanical macroretention

Buccal technique:-Lingual technique: microetching

Mechanical microretention

Conditioning of enamel with 30%-40% phosphoric acid

Chemical bonding

Primer-i.e., unfilled monomer or microfilled monomer penetrates into the mechanical microretentions created by enamel etching

Bonding agent

Composite or compomer

Table 6.3

Bonding to existing composite fillings, composite veneers, or acrylic denture teeth

 

Mechanical macroretention

Roughening of the surface with a microetcher or with a tungsten carbide burr

Additional bond strength enhancer

Polymer conditioner

Chemical bonding

Primer-i.e., unfilled or microfilled monomer penetrates into the mechanical macro-retentions and dissolves the polymer chains of the surrounding acrylic

Bonding agent

Composite

Table 6.4

Bonding to ceramic

 

Mechanical macroretention

Roughening of the surface with microetcher or fine diamond burrs

Mechanical microretention

Conditioning of the ceramic with 15%-20% hydrofluoric acid

Additional chemical bonding

Silane agent: porcelain conditioner (Reliance Orthodontics) or silane coupling agent (Espe)

Chemical bonding

Primer-i.e., unfilled or microfilled monomer uses both mechanical macroretention and microretention, and a chemical bond via silane coupling agents

Bonding agent

Composite

Table 6.5

Bonding to metal surfaces (gold, amalgam, and nonprecious metals)

 

Mechanical macroretention

Roughening of the surface with microetch or with fine diamonds

Mechanical microretention

Acid-etch conditioning generally not necessary

Additional chemical bonding

Metal primer based on triphosphorus methacrylate

Chemical bonding

Primer: unfilled primer or microfilled, which primarily uses mechanical retention

Bonding agent

Composite

NOTE

Table 6.6 Bonding protocols for various surfaces
 

Mechanical macroretention

Mechanical microretention

Additional chemical bond enhancers

Chemical priming agents

Bonding agents

Enamel

 

30%-40% phosphoric acid

 

Primer uses mainly mechanical micro-retention created from enamel conditioning

Composite or compomer

Dentin

 

Cleaning and “roughening” of surface to reveal dentin channels

 

Primer, mainly via dentin channels

Compomer or glass ionomer cement

Gold, amalgam, non-precious metals

Microetch and/or roughening with a fine diamond

 

Metal primer (triphosphorus metha-crylate-based)

Primer uses mainly macroretention

Composite

Composite

Microetch and/or roughening with tungsten carbide burr

 

Polymer conditioners

Primer uses macroretention and chemical bonding via dissolved polymer chains

Composite

Ceramic

Microetch and/or roughening with a fine diamond

Hydrofluoric acid 15%-20%

Silane agents

Primer uses macroretention and chemical bonding via silane coupling

Composite

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Jul 7, 2020 | Posted by in Orthodontics | Comments Off on Bonding
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