Dental bonding in dentistry

In this article, we talk in depth about dental bonding dental bonding and why it plays such an important role in restorative dentistry, as well as the types of adhesive systems, existing techniques and the latest developments in the field.

Why is dental bonding important in restorative dentistry?

Dental bonding allows restorative materials to bond firmly to enamel and dentin. materials to bond firmly to enamel and dentin.. This process involves a biochemical and mechanical interaction between dental substrate and adhesive, which is necessary to achieve a good clinical result. In this way, it contributes to preserving tooth structure, preventing leaks that cause secondary caries and improving the retention of the restoration and dental esthetics.

For this purpose, adhesive systems are used, products composed of one or more components, which prepare the tooth surface and facilitate adhesion. In direct direct restorations, such as composite resin fillingssuch as composite fillings, dental adhesion prevents the material from shifting, fracturing or detaching. In indirect indirect restorationssuch as crowns or veneers, it ensures a strong bond, helping to preserve healthy tooth tissue.

Types of adhesive systems

Advances in adhesive systems today offer many more options, being less invasive and more resistant. less invasive and more resistant in the long term. The main types are 3-step adhesives, 2-step adhesives, self-etching systems and universal adhesives.

1. 3-step adhesives (etch-and-rinse)

This is the classic system and consists of three phases. It starts with acid etching to create a rough surface rough surface with microporosities on the tooth. Then comes the application of the adhesive using two liquids: primer and bond. The primer contains amphiphilic monomers capable of working on wet dentin, while the bond is the adhesive that will bond to the restorative material. Finally, blue light curing is applied for hardening and bonding.

2. 2-step adhesives

In this method, some products are combined are combined to speed up the procedure. First, the tooth is etched with phosphoric acid to prepare the tooth, then a solution is applied that already contains both the primer and the bond. The mixture is applied to the surface and light cured with blue light.

Self-etching systems (self-etch)

Use an acid primer that etches and conditions the tooth surface in a single step. On enamel, etching is less aggressive, so the result is more superficial, while on dentin the primer removes the smear layer without exposing the tubuli. It is very useful in enamels with fluorosis or hypomineralization as it reduces the risk of interference caused by residual water.

4. Universal adhesives

These are the most versatileThey can be used for many types of teeth and clinical conditions, including enamel with fluorosis or hypomineralization. They can be used as etch-and-rinse or self-etch and, in the latter case, it is important to apply the adhesive with active pressure to improve adhesion.

Dental bonding techniques

The success of the adhesion, beyond the system used, also depends on the correct also depends on the correct application of the system. Therefore, it is important to prepare the dentin and enamel well, to control humidity and insulation, and to be meticulous when applying the adhesive.

1. Enamel and dentin preparation 

As mentioned above, the tooth surface is prepared before applying the adhesive. With 37% phosphoric acid in the form of a colored gel, a rough surface is created on the enamel: it is left for 15 to 60 seconds, according to the manufacturer's instructions, rinsed with water and air-dried. For normal, healthy enamel, 15 seconds is sufficient, while for teeth with fluorosis or hypomineralization the process is extended until a chalky white surface is achieved.

When the enamel presents defects in its development may have organic residues that interfere with adhesion, so deproteinization is used to remove them. The following can be applied sodium hypochlorite (NaClO 5 or 5.25%) can be applied before or after etching.

2. Moisture control and insulation

Moisture can alter the outcome of a dental restoration if it is not well controlled. The presence of water or saliva where the adhesive where the adhesive is to be placed can affect the penetration and polymerization of the adhesive, causing the restoration to peel off or cause sensitivity.

3. Adhesive application

Each adhesive needs to be applied in a specific way and has a specific time for both placement and light curing. On the other hand, during active active application the adhesive should be rubbed in order to better penetrate the tooth surface. In addition, just the right amount of adhesive should be used, enough to cover the tooth well without leaving too thick a layer that could reduce the strength of the bond.

4. Common mistakes and how to avoid them

Among the most common mistakes when using dental adhesives are too much or too little acid etching. Too little etching does not properly form the rough surface necessary for the component to bond, while too much etching can lead to excessive demineralization of the enamel and in dentin, prolonged exposure to acid can reduce bonding efficiency.

Then, if the enamel and/or dentin come into contact with saliva after etching, the bond is after etching, the bond is weakened. Absolute isolation with a rubber dam will keep the area clean and dry. Also, if the light curing is insufficient, either because it is used for a short time or because it is underpowered, the adhesive will not cure well. The lamp must be of high quality and respect the exposure times indicated by the manufacturer.

New developments in dental bonding

One of the recent improvements in adhesive materials and techniques consists of the application of the most advanced advanced functional monomers: they bind better to hydroxyapatiteThe most advanced functional monomers: they bind better to hydroxyapatite, achieving a stronger adhesion that reduces post-treatment sensitivity and improves marginal sealing. There are also the easy-to-use, minimally invasive infiltrating resins that penetrate enamel defects (DDE) to disguise opacities and stop demineralization, as well as acid etching techniques to achieve a better bonding pattern on teeth with dental fluorosis or hypomineralized teeth.

Finally, it is worth mentioning the experimental phase studies studies being carried out with silver nanoparticles, laser engraving and microfiltration with methacrylate. Continuing education is the only way to keep abreast of advances in dentistry.